System and method for treating a gas

Abstract

The present invention includes a gas processing system for converting a hydrocarbon-containing inlet gas into effluent gas products, the system including a gas delivery subsystem, a plasma reaction chamber, and a microwave subsystem, the gas delivery subsystem being in fluid communication with the plasma reaction chamber such that the gas delivery subsystem directs the hydrocarbon-containing inlet gas to the plasma reaction chamber, and the microwave subsystem directs microwave energy to the plasma reaction chamber to energize the hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, the plasma effecting conversion of hydrocarbons in the hydrocarbon-containing inlet gas to effluent gas products comprising acetylene and hydrogen. The present invention also includes methods for using this gas processing system.

Description

Technical Field

[0001] Related Applications This application claims the benefit of U.S. Provisional Application No. 62 / 964,977, filed Jan. 23, 2020; U.S. Provisional Application No. 62 / 969,494, filed Feb. 3, 2020; U.S. Provisional Application No. 62 / 986,998, filed Mar. 9, 2020; U.S. Provisional Application No. 63 / 019,851, filed May 4, 2020; and U.S. Provisional Application No. 63 / 052,524, filed Jul. 16, 2020. The entire teachings of the above applications are incorporated herein by reference.

Background Art

[0002] Background Acetylene can be used as a chemical precursor or feedstock for industrial combustion applications such as welding and metal cutting. The commercial production of acetylene has been carried out since the early 20th century. The first method for acetylene production used coal as a raw material, but the process involved a calcium carbide intermediate. In the late 20th century, other methods mainly using heat-based processes such as thermal cracking or electric arc furnaces were developed.

[0003] Acetylene made from coal involves a three-step process: First, coal is heated to produce high-carbon-content coke; second, the coke is further heated in the presence of calcium oxide to produce calcium carbide; third, the calcium carbide is reacted with water to produce acetylene and calcium hydroxide. The first two steps require very high temperatures, while the last step is exothermic. This method for forming acetylene is still commercially used, especially in China where coal is readily available.

[0004] However, this process brings impurities from the coal and lime raw materials into the final product, so the resulting acetylene is contaminated with impurities such as phosphine, arsine, and bisulfate. Since all of these species can contaminate the catalyst for subsequent chemical reactions, it is necessary to wash them from the acetylene product before it can be used commercially. Chemically pure acetylene for further chemical processing must be 99.6% pure C2H2 with <25 ppm of phosphine / arsine / H2S. Industrial grade acetylene burned for welding and metal cutting applications can tolerate more impurities (>98.0% pure C2H2, <500 ppm phosphine / arsine / H2S). Therefore, the coal-derived production of acetylene is restricted in the United States to the formation of industrial grade acetylene; furthermore, even when coal-derived acetylene is used only for welding and metal cutting, the presence of potentially dangerous contaminants raises concerns.

[0005] As an alternative, acetylene can be prepared from hydrocarbons by partial oxidation by a process developed by BASF as described, for example, in U.S. Patent No. 5,824,834. In this process, the hydrocarbon feedstock and oxygen are preheated and then reacted in a combustion chamber to reach a temperature of >1500 °C for the gas produced. The combustion reaction is quenched with water for rapid cooling, resulting in a gas mixture of acetylene, hydrogen, carbon monoxide, steam, and by-products (referred to as "cutting gas"). This method of acetylene production produces large amounts of hydrogen (57%), carbon monoxide (26%), and methane (5.2%) along with about 7.5% acetylene. One of the by-products is soot that needs to be removed from it if the cutting gas is to be further processed. Other by-products include higher hydrocarbons such as alkanes, alkenes, alkynes, and aromatics. Removing impurities from the cutting gas and recovering the acetylene it contains involves significant engineering difficulties.

[0006] In addition to production problems, acetylene is difficult to handle and transport. It is highly explosive. When transported through pipelines, it is kept at low pressure and carried only over short distances. For industrial purposes, acetylene is pumped into cylinders at high pressure and dissolved in a solvent such as dimethylformamide, N-methyl-2-pyrrolidone or acetone. When an acetylene cylinder is opened, the dissolved gas evaporates and flows through a connecting hose to a welding and cutting torch. However, a certain amount remains dissolved in the solvent and is returned to the manufacturer in this state, so not all of the acetylene in the cylinder is available for use. With the emergence of the petrochemical industry in the mid-20th century, acetylene has continued to be used industrially (i.e., for welding, metal cutting, etc.), but acetylene has been replaced as a precursor for chemical reactions and supplanted by other feedstocks (e.g., ethylene) directly derived from petroleum rather than coal. As oil became more expensive and natural gas became cheaper, interest in acetylene increased as a platform for further chemical processing in place of oil-derived feedstocks.

[0007] Furthermore, the abundance of natural gas drives the search for more ways to use this material without burning it, to reduce its greenhouse gas impact, and to avoid conversion to CO2, another greenhouse gas from simple combustion. In addition to natural gas, other mixed gas sources such as oceanic clathrates, coalbed gas, and biogas contain methane gas. Biogas is a naturally produced mixed gas source that results from the anaerobic decomposition of organic waste materials in various human-made environments such as landfills, manure holding ponds, waste facilities, etc., and in natural environments such as peatlands, melting permafrost layers, etc. Anaerobic bacteria that occur in such environments digest the organic materials that accumulate there to produce a gas mixture mainly composed of carbon dioxide and methane. Since methane is potentially flammable, biogas with a high methane content can be dangerous as can be seen in gas mixtures from landfills. Furthermore, methane is a potential greenhouse gas. Currently, biogas recovered from organic decomposition (e.g., landfills, waste facilities, holding ponds, etc. or natural areas containing decaying organic materials) can be purified to remove CO2 and other trace gases, producing high-concentration methane for generating energy. However, simply burning methane-rich biogas produces CO2, another greenhouse gas. It is desirable to identify uses for biogas or other mixed gas sources that can harness their energy potential without burning them, and to reduce the greenhouse gas impact of methane while avoiding converting it to CO2, another greenhouse gas.

[0008] Increasing the demand for non-hydrocarbon sources of fuel supports the use of methane as a feedstock for producing hydrogen that can then be used as a power source. Prior art already exists for extracting hydrogen gas from methane in natural gas. For example, steam reforming can produce hydrogen gas and carbon monoxide; the hydrogen produced by the steam reforming process can then be used in pure form for other applications such as hydrogen fuel cells or gas turbines, where hydrogen combines with oxygen to form water without the release of greenhouse gases. Other processes such as partial oxidation can produce hydrogen-rich synthesis gas, a combustible mixture that can be used as a fuel. However, prior art for producing hydrogen from methane has drawbacks. Steam reforming is carried out at high temperatures, uses large amounts of energy, and requires expensive materials that can withstand harsh reaction conditions. Steam reforming uses a catalyst to convert methane to hydrogen, but the catalyst is vulnerable to contamination by common pollutants. Partial oxidation is a less efficient technique for producing hydrogen than steam reforming, is prone to forming soot, and has a limited hydrogen yield. Currently, more than 90% of hydrogen is produced by thermochemical processes using hydrocarbon sources, but this can also be produced by electrolysis of water and other non-carbon chemical processes.

[0009] Hydrogen, a zero-emission fuel source, can be used for a variety of commercial applications. Most hydrogen is used as a feedstock for industrial chemical processes, but hydrogen is gaining wider acceptance as a fuel source that can replace hydrocarbons. For example, hydrogen can power fuel cells or internal combustion and combines with oxygen in the atmosphere when burned. Thus, this use of hydrogen as a fuel avoids the production of carbon-based greenhouse gases such as carbon dioxide. Hydrogen is increasingly being used to power vehicles such as trucks and passenger cars and is already an established fuel for mass transit vehicles such as buses. With the emergence of a so-called "hydrogen economy" in which hydrogen is used as a fuel source for heat generation, for vehicles, and for long-distance energy transport, more demand for hydrogen is expected.

[0010] Therefore, there is a need in the art for processes that form more valuable products using a mixed gas feed source such as natural gas or biogas and / or a more refined hydrocarbon feedstock (e.g., methane, ethane, propane, and butane and combinations thereof). For these processes intended to produce acetylene, it is advantageous to use a mixed gas feed source such as natural gas or biogas and / or a more refined hydrocarbon feedstock (e.g., methane, ethane, propane, and butane) as the feedstock and to avoid the limitations of other mixed gas conversion processes or hydrocarbon combustion processes while leveraging the abundance of these feedstock materials.

[0011] At the same time, there is a need in the art for processes that can produce acetylene in a convenient and cost-effective manner using a mixed gas feed source such as natural gas or biogas and / or a more refined hydrocarbon feedstock. It is particularly advantageous to produce acetylene with minimal impurities so that the acetylene can be used safely and without substantial further processing. Furthermore, there is a further need in the art to provide alternative fuels such as hydrogen on a large scale in a realizable and efficient manner. It is desirable to carry out these processes in an economically and environmentally responsible way.

[0012] Also, acetylene has usefulness in various industrial applications, for example, as a fuel for metal cutting. This application represents a large market of comparable size to the various petrochemical applications of acetylene. Currently, the major industrial use of acetylene is as a fuel for oxyacetylene torches used to cut steel; in addition to cutting, acetylene is used in some welding, carburizing, and heat treating of steel. Oxyacetylene torches burn at a higher flame temperature (3,500 °C) than other oxygen-fuel torches such as oxygen(hydrogen (3,000 °C) and oxygen - propane (2,500 °C) torches, and oxyacetylene forms a smaller, more precise flame cone. These characteristics enable a higher quality and more precise cut than other comparable oxygen-fuel cutting methods. Further, the combustion of acetylene requires a smaller stoichiometric ratio of oxygen than other fuels such as propane, so an oxygen-acetylene torch consumes less oxygen than other oxygen-fuel torches, resulting in a reduction in oxygen operating costs. Finally, the lower flame temperature and higher oxygen requirements of other hydrocarbon fuel types such as oxygen-propane torches result in a higher risk of incomplete combustion, producing dangerous carbon monoxide in the working environment. For the reasons described above, oxygen-acetylene cutting is standard in the industry for steel cutting.

[0013] However, as described previously, there are limitations to the production and transport of acetylene. As a result, procuring acetylene for industrial cutting is expensive and logistically difficult. First, acetylene, used as a fuel for torches, must be transported and stored in small metal cylinders due to the risk of explosion. To reduce the risk of explosion, the acetylene in the cylinder is dissolved in acetone, reducing its partial pressure and thus the likelihood of explosion. Due to the presence of acetone in the cylinder with acetylene, acetylene can only be withdrawn at low flow rates (e.g., not exceeding 1 / 7 of the container content per hour) to reduce the chance that acetone will be drawn out into the outflow line with the acetylene - Acetone in the gas supply can lower the flame temperature and the quality of the cutting process. Even with a low outflow rate, the acetylene in the cylinder can be quickly depleted; once depleted, the cylinder cannot be refilled on - site without extensive safety infrastructure and expertise due to the risk of explosion. Due to their small size, the cylinders are not adequately scaled for larger operations but instead must be connected in parallel via manifolding, adding to the complexity of the planning. Also, due to the risk of explosion, the cylinders require several safety precautions when they are transported, adding cost and logistical difficulties.

[0014] A need remains in the art for a more efficient and safer method of procuring acetylene. It is desirable to avoid the need for acetone - containing cylinders as containers for acetylene gas used in metalworking. For example, it would be useful to make acetylene fuel available on - demand and as needed, avoiding the volume and flow rate constraints of cylinder storage. Also, it would be advantageous to produce acetylene in close proximity to its point of use, avoiding cylinder - specific difficulties associated with transport.

[0015] Acetylene is also useful as a precursor or substrate for various chemical reactions. One example is the production of polyvinyl chloride made from vinyl chloride monomer (VCM). To produce VCM, currently two industrial processes are used: (i) chlorination of ethylene to form dichloroethylene, followed by thermal cracking to produce VCM and HCl; and (ii) direct oxidation of acetylene. For this latter process, catalysts such as mercury chloride, activated carbon, ruthenium and gold-based catalysts are used. This latter process of direct oxidation of acetylene is particularly desirable in an environment where there is an abundant and reliable source of acetylene. However, the above-mentioned production, storage and transportation problems affect the availability of acetylene used in VCM production. Since it is advantageous to provide acetylene in a convenient and cost-effective manner, acetylene can be easily used as a precursor in VCM production. It is particularly advantageous to provide a source of acetylene for VCM production having minimal impurities, so that acetylene can be used safely without substantial further processing. Also, it is advantageous to produce acetylene for large-scale and efficient VCM production without the need for complex logistics. Desirably, the process for VCM production can be integrated with the process for producing acetylene, thus avoiding the difficulties of acetylene transportation and storage.

[0016] Another example of using acetylene as a precursor for chemical reactions is the production of vitamins A and E. Acetylene is useful as a feedstock for making these vitamins and provitamins such as β-carotene and their chemical intermediates, but its industrial use is accompanied by difficulties. As yet another example of using acetylene as a precursor for chemical manufacture, acetylene can be decomposed to produce hydrogen gas and solid carbon. The granular carbon produced by this reaction, called acetylene black, is particularly useful for forming long chains of carbon with excellent electrical and thermal conductivity in its small and uniform primary particle form. Due to its physical structure and purity, acetylene black is a more valuable material than standard carbon black. This is used, for example, in the manufacture of batteries, conductive polymers and other special products.

[0017] The introduction of acetylene to the manufacturing site as a precursor for chemical reactions such as those described above incurs high transportation costs due to its explosive nature; commercial grade acetylene can contain impurities; and the material itself can be in short supply. Further, all current technologies for making acetylene (using calcium carbide, partial oxidation or cracking) have process-specific drawbacks. Since it would be advantageous to make acetylene for vitamin manufacture or for making acetylene black with minimal impurities, acetylene can be used in these processes without substantial further processing. Also, it would be advantageous to provide a supply that can be scaled up on-site and tailored to meet the manufacturer's needs without the need for complex logistics. Desirably, the process for vitamin manufacture or acetylene black manufacture can be integrated with the process for making acetylene, thus avoiding the difficulties of acetylene transportation and storage.

[0018] Hydrogen, such as acetylene, has many uses in industrial chemistry. However, its conventional production involves technologies such as steam methane reforming and electrolysis, which require a significant energy input. Furthermore, steam methane reforming and similar industrial implementations themselves produce carbon monoxide or carbon dioxide as part of those hydrogen formation reactions, offsetting the net environmental benefits that could result from the use of hydrogen as a fuel instead of hydrocarbons. Therefore, it is desirable to produce hydrogen for use as a zero-emission fuel in a way that does not produce additional greenhouse gases and does not consume excessive amounts of energy.

[0019] Furthermore, regardless of its environmental benefits, hydrogen faces significant logistics and distribution challenges that offset its zero-carbon footprint. Conventional thermochemical technologies for producing hydrogen typically require large-scale industrial facilities that are generally located away from the end-users. Therefore, once hydrogen is produced, it must be stored and / or transported over long distances. Currently, the infrastructure for transporting hydrogen from the point of production to the point of use includes a mix of pipelines, tank trucks, tube trailers, etc. as transportation methods, all of which can add their own carbon load to the atmosphere. Also, hydrogen must be stored and transported as a cryogenic liquid or highly compressed gas, with the potential for leakage and explosion, making the industrial use of hydrogen more difficult for customers. It is advantageous to produce hydrogen in smaller facilities that can be located closer to the end-users, reducing the complexity of transporting this fuel over long distances. It is also advantageous to provide on-demand production of hydrogen, potentially eliminating the need for significantly complex logistics. SUMMARY OF THE INVENTION

[0020] Summary of the Invention In an aspect, a gas treatment system for converting a hydrocarbon-containing inlet gas to an outlet gas product is disclosed herein, the system including a gas delivery subsystem, a plasma reaction chamber, and a microwave subsystem, where the gas delivery subsystem is in fluid communication with the plasma reaction chamber and directs the hydrocarbon-containing inlet gas to the plasma reaction chamber, and the microwave subsystem directs microwave energy to the plasma reaction chamber to energize the hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, and the plasma effects the conversion of hydrocarbons in the hydrocarbon-containing inlet gas to an outlet gas product including acetylene and hydrogen. In an aspect, the hydrocarbon-containing inlet gas can be derived from a gas mixture source, which can be natural gas or biogas; in an aspect, the hydrocarbon-containing inlet gas includes a gas selected from the group consisting of methane, ethane, propane, and butane, and the hydrocarbon-containing inlet gas can consist essentially of methane. In an aspect, the gas delivery subsystem includes a delivery conduit and a gas injector, where the delivery conduit is in fluid communication with the gas injector and delivers one or more gases to the gas injector, and the gas injector delivers one or more gases to the plasma reaction chamber. The delivery conduit can include a supply gas transport circuit that delivers the hydrocarbon-containing inlet gas to the gas injector, and the hydrocarbon-containing inlet gas can include methane or can consist essentially of methane. In an aspect, the delivery conduit includes an additional gas transport circuit that delivers an additional gas to the gas injector, and the additional gas can be hydrogen. In an aspect, the additional gas transport circuit is an auxiliary gas transport circuit that delivers an auxiliary gas to the gas injector, or the additional gas transport circuit is a recycled gas transport circuit that delivers a recycled gas to the gas injector. The recycled gas can include hydrogen, or it can include a hydrogen-rich reactant gas, or it can consist essentially of hydrogen, or it can consist essentially of a hydrogen-rich reactant gas. In an aspect, the delivery conduit delivers each of the one or more gases to the gas injector through a separate path.In an embodiment, the gas injector includes an injector body portion including two or more separate coaxially arranged gas feeds, wherein a first gas feed conveys a hydrocarbon-containing influent gas through a first set of one or more nozzles to a plasma reaction chamber, and a second gas feed conveys additional gas through a second set of one or more nozzles to the plasma reaction chamber. In an embodiment, at least one of the one or more nozzles is oriented at an angle with respect to the longitudinal axis of the plasma reaction chamber or at an angle with respect to the transverse axis of the plasma reaction chamber. In an embodiment, at least one of the one or more nozzles is oriented at an angle with respect to the longitudinal axis or the transverse axis of the injector body portion. The combined gas flow from the first set of nozzles and the second set of nozzles creates a swirling flow within the plasma reaction chamber. In an embodiment, the plasma reaction chamber is disposed within an elongated reactor tube having proximal and distal ends, and the elongated reactor tube is dimensionally adapted for interaction with a microwave subsystem. The elongated reactor tube can be a quartz tube. The plasma reactor chamber can be disposed at approximately the middle portion of the elongated reactor tube. In an embodiment, the gas injector conveys the hydrocarbon-containing influent gas and additional gas to the proximal portion of the elongated reactor tube, where the hydrocarbon-containing influent gas and additional gas flow distally therefrom toward the plasma reaction chamber. The gas injector can be centrally disposed within the proximal portion, and the first set of one or more nozzles and the second set of one or more nozzles are oriented peripherally; alternatively, the gas injector is disposed at the periphery within the proximal portion, and the first set of one or more nozzles and the second set of one or more nozzles are oriented centrally. In an embodiment, the microwave subsystem includes an applicator for directing microwave energy to the plasma reaction chamber, and the plasma reaction chamber is disposed in a region of the elongated reactor tube that passes through and intersects the applicator perpendicularly. The applicator can be a single-arm applicator.In an aspect, the microwave subsystem further includes a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is conveyed by the waveguide to the applicator, and the applicator directs the microwave energy into a reaction chamber within an elongate reactor tube, thereby forming a plasma in the plasma reaction chamber. The magnetron can generate L-band microwave energy. In an aspect, the plasma in the plasma reaction chamber generates an effluent gas product, and the effluent gas product flows distally within the plasma reaction chamber toward the distal end of the elongate reactor tube. The effluent product can exit from the distal end of the elongate reactor tube and enter an effluent separation and disposal subsystem. In an aspect, the effluent separation and disposal subsystem can include a solid filter and a cold trap, and / or can include an adsorption column, and / or can include a pressure swing adsorption system adapted to remove non-hydrogen components from the effluent stream, and / or can include a temperature swing adsorption system adapted to remove higher acetylenes from the effluent stream, and the temperature swing adsorption system can include a regular cycle temperature swing adsorber.

[0021] In one aspect, the present invention relates to a system for converting a hydrocarbon-containing influent gas into an effluent gas product, the system including a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and an effluent separation and disposal system; where the gas delivery subsystem: i. is in fluid communication with the plasma reaction chamber and directs one or more gases into the plasma reaction chamber, where the one or more gases include the hydrocarbon-containing influent gas; and ii. includes a delivery conduit and a gas injector, a. where the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers one or more gases to the gas injector, and the delivery conduit includes a supply gas conveyance circuit that delivers the hydrocarbon-containing influent gas to the gas injector, b. and the gas injector delivers one or more gases into the plasma reaction chamber; the plasma reaction chamber: i. in fluid communication with an effluent separation and disposal system; ii. disposed within an elongate reactor tube having proximal and distal ends, the elongate reactor tube being dimensionally adapted for interaction with a microwave subsystem; The microwave subsystem comprises: i. directing microwave energy to a plasma reaction chamber to energize a hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma effects conversion of the hydrocarbon in the hydrocarbon-containing inlet gas to an effluent gas product, the effluent gas product including acetylene and hydrogen; ii. including an applicator for directing microwave energy to the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of the elongate reactor tube that passes through and intersects the applicator perpendicularly; and iii. further including a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, the microwave energy being conveyed by the waveguide to the applicator, the applicator directing the microwave energy to the reaction chamber within the elongate reactor tube, thereby forming a plasma in the plasma reaction chamber, where the effluent gas product flows within the plasma reaction chamber toward the distal end of the elongate reactor tube, exits the distal end of the elongate reactor tube, and forms an effluent stream that enters the effluent separation and disposal subsystem, The effluent separation and disposal system includes a short cycle temperature swing adsorption system adapted to separate hydrogen from the effluent stream.

[0022] In an aspect, the exhaust separation and disposal system includes a temperature swing adsorption system adapted to separate hydrogen from the exhaust stream, and the temperature swing adsorption system may include a short cycle temperature swing adsorber. In other aspects, the exhaust separation and disposal system includes a regular cycle temperature swing adsorption system adapted to separate higher acetylenes from the exhaust stream and a short cycle temperature swing adsorption system adapted to separate hydrogen from the exhaust stream. In an aspect, the regular cycle temperature swing adsorption system is disposed upstream from the short cycle temperature swing adsorption system.

[0023] Additionally or alternatively, in an aspect, the exhaust separation and disposal subsystem may include an adsorption column that can adsorb acetylene in an aspect, and / or may include a concentrated acid in an amount sufficient to oxidize higher hydrocarbons, and / or may include a catalyst suitable for converting higher hydrocarbons to derivative compounds separable from the exhaust stream, and / or may include a condenser, and / or may include a gas separation membrane array that can separate hydrogen from the exhaust stream in an aspect, and / or may include a hydrogen separation subsystem that can be in fluid communication with a recirculation gas transport circuit, where the hydrogen recovered by the hydrogen separation subsystem is recirculated to the recirculation gas transport circuit, and / or may include an acetylene separation subsystem.

[0024] A method for treating a hydrocarbon-containing feed gas to produce acetylene gas is further disclosed herein. The method includes providing a hydrocarbon-containing feed gas, injecting the hydrocarbon-containing feed gas into a reaction chamber, supplying microwave energy to the hydrocarbon-containing feed gas in the reaction chamber to generate a plasma, forming a gas product within the plasma, wherein one of the gas products is acetylene gas, and flowing the gas product out of the reaction chamber. In a further aspect, the invention includes a method for treating a hydrocarbon-containing feed gas to produce an effluent gas product, where the effluent gas product contains acetylene and hydrogen. The method includes injecting the hydrocarbon-containing feed gas into a plasma reaction chamber, supplying microwave energy to the hydrocarbon-containing feed gas in the plasma reaction chamber to generate a plasma, forming an effluent gas product within the plasma, where the effluent gas product contains acetylene and hydrogen, flowing the effluent gas product out of the plasma reaction chamber, and removing hydrogen from the effluent gas product by short cycle temperature swing adsorption. In an aspect, the hydrocarbon-containing feed gas is from a mixed gas source, and the mixed gas source can be natural gas or biogas. In an aspect, the hydrocarbon-containing feed gas contains a gas selected from the group consisting of methane, ethane, propane, and butane, and it can consist essentially of methane. In a particular implementation, the method further includes providing one or more additional gases simultaneously with the step of providing the hydrocarbon-containing feed gas, and the one or more additional gases can be selected from the group consisting of hydrogen, nitrogen, and recycle gas. In an aspect, the recycle gas contains a hydrogen-rich reactant gas, which can consist essentially of hydrogen. In a particular implementation, the method further includes separating acetylene gas from the effluent gas product after the step of flowing the gas product out of the reaction chamber. In a further aspect, the method further includes separating acetylene gas from the effluent gas product after the step of removing hydrogen from the effluent gas product by short cycle temperature swing adsorption. In a particular implementation, the method further includes recycling at least one of the gas products.In an embodiment, at least one gaseous product may comprise hydrogen gas or may consist essentially of hydrogen gas.

[0025] Methods for converting a hydrocarbon-containing inlet gas to an outlet gas are also disclosed herein, the method comprising providing a hydrocarbon-containing inlet gas, directing the hydrocarbon-containing inlet gas to the gas treatment system described above, and using the gas treatment system described above to treat the hydrocarbon-containing inlet gas to convert the inlet gas to an outlet gas, the outlet gas comprising acetylene. In an embodiment, the hydrocarbon-containing inlet gas is from a mixed gas source, which may be natural gas or biogas. In an embodiment, the outlet gas further comprises hydrogen. The present invention also encompasses a method for converting a hydrocarbon-containing inlet gas to an outlet gas product, the method comprising providing one or more gases, wherein the one or more gases comprise a hydrocarbon-containing inlet gas; directing the hydrocarbon-containing inlet gas to the system described herein, wherein a delivery conduit delivers the one or more gases to a gas injector, the gas injector delivers the one or more gases to a plasma reaction chamber; wherein a microwave subsystem directs microwave energy to the plasma reaction chamber to convert the one or more gases to a plasma, the plasma effecting the conversion of hydrocarbons in the hydrocarbon-containing inlet gas to an outlet gas product; the outlet gas product flows in the plasma reaction chamber towards the distal end of an elongated reactor tube, exits from the distal end of the elongated reactor tube, and forms an exhaust stream entering a waste separation and disposal subsystem; and a short cycle temperature swing adsorption system removes hydrogen from the exhaust stream.

[0026] Also disclosed herein is a gas treatment system described herein and a storage system for containing an effluent gas product produced by the system; and a metal cutting system including an apparatus for metal cutting in fluid communication with the storage system, where the apparatus withdraws the effluent gas product from the storage system and ignites them for use in metal cutting. In an aspect, the apparatus is an acetylene torch or an oxyacetylene torch. In an aspect, the metal cutting system further includes a hydrogen separation system in fluid communication with the gas treatment system described above, where the effluent gas flows to the hydrogen separation system, the hydrogen separation system separates the effluent gas into two product streams, one product stream is an acetylene-rich gas; and the apparatus for metal cutting uses the acetylene-rich gas stored in the storage system as a fuel for metal cutting.

[0027] Also disclosed are a gas treatment system and method for converting a hydrocarbon-containing inlet gas to vinyl chloride monomer (VCM). The present invention encompasses a system for converting a hydrocarbon-containing inlet gas to a VCM (vinyl chloride monomer)-containing liquid product, including a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and a VCM reactor and separator subsystem; where the gas delivery subsystem is: i. in fluid communication with the plasma reaction chamber and directing one or more gases to the plasma reaction chamber, where the one or more gases include the hydrocarbon-containing inlet gas; and ii. including a delivery conduit and a gas injector, a. where the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers one or more gases to the gas injector, and the delivery conduit includes a supply gas transport circuit for delivering the hydrocarbon-containing inlet gas to the gas injector, b. the gas injector delivers one or more gases to the plasma reaction chamber; The plasma reaction chamber is: i. in fluid communication with an effluent separation and disposal system; ii. disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem; The microwave subsystem comprises: i. directing microwave energy towards a plasma reaction chamber to supply energy to a hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma effects the conversion of hydrocarbons in the hydrocarbon-containing inlet gas to an outlet gas product, the outlet gas product including acetylene and hydrogen; ii. including an applicator for directing microwave energy towards the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of an elongate reactor tube that passes through and intersects the applicator perpendicularly; and iii. further including a power source, a magnetron, and a waveguide, the power source supplying energy to the magnetron to generate microwave energy, where the microwave energy is conveyed by the waveguide to the applicator, the applicator directing the microwave energy towards the reaction chamber within the elongate reactor tube, thereby forming a plasma in the plasma reaction chamber, where the outlet gas product flows towards the distal end of the elongate reactor tube within the plasma reaction chamber, exiting the distal end of the elongate reactor tube to form an outlet stream entering a VCM reactor and a separator subsystem, the VCM reactor and separator subsystem including a VCM reactor and a plurality of separators; i. where the plurality of separators includes a first separation system, a second separation system, and a third separation system; ii. the first separation system is an effluent separator in fluid communication with the elongate reactor tube, adapted to remove higher acetylenes and aromatics from the outlet stream to produce a purified effluent stream delivered to the VCM reactor, where the purified effluent stream includes acetylene gas; and where: (a) the VCM reactor is in fluid communication with the first separation system and the second separation system; (b) the VCM reactor receives the purified effluent stream and directs the purified effluent stream across a catalyst bed that reacts acetylene gas with a stream of hydrogen chloride gas to produce VCM; (c) The VCM reactor discharges the VCM formed therein into a gaseous VCM-containing effluent stream that is directed to a second separation system; iii. Here, the second separation system is a compression system including a compressor, a refrigeration chamber, and a liquid-gas separator, and the second separation system is adapted to compress the VCM into liquid VCM, separate the liquid VCM from the VCM effluent stream, and produce a VCM-containing liquid product and a residual gas stream; iv. The residual gas stream is directed to a third separation system in fluid communication with the second separation system, and the third separation system processes the residual gas stream to separate purified hydrogen from the residual gas.

[0028] The present invention also includes a system for converting a hydrocarbon-containing influent gas into a VCM (vinyl chloride monomer)-containing liquid product, including a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, a VCM reactor, and a separator subsystem; wherein the gas delivery subsystem is: i. in fluid communication with the plasma reaction chamber, directing one or more gases to the plasma reaction chamber, where the one or more gases include a hydrocarbon-containing influent gas; and ii. including a delivery conduit and a gas injector; a. Here, the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers one or more gases to the gas injector, and the delivery conduit includes a supply gas transport circuit that delivers the hydrocarbon-containing influent gas to the gas injector, b. The gas injector delivers one or more gases to the plasma reaction chamber; The plasma reaction chamber is: i. in fluid communication with an effluent separation and disposal system; ii. disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem; The microwave subsystem is: i. Direct microwave energy towards a plasma reaction chamber to supply energy to a hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma performs the conversion of hydrocarbons in the hydrocarbon-containing inlet gas to outlet gas products, and the outlet gas products include acetylene and hydrogen; ii. Include an applicator for directing microwave energy towards the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of an elongated reactor tube that passes through and intersects the applicator perpendicularly; and further include a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is conveyed by the waveguide to the applicator, and the applicator directs the microwave energy towards the reaction chamber within the elongated reactor tube, thereby forming a plasma in the plasma reaction chamber, where the outlet gas products flow towards the distal end of the elongated reactor tube within the plasma reaction chamber, exiting the distal end of the elongated reactor tube to form an outlet stream that enters a VCM reactor and a separator subsystem, and the VCM reactor and separator subsystem include a VCM reactor and a plurality of separators; i. where the plurality of separators include a first separation system, a second separation system, and a third separation system; ii. The first separation system in fluid communication with the elongated reactor tube is an exhaust separator adapted to remove higher acetylenes and aromatics from the outlet stream to produce a purified exhaust stream containing acetylene gas and hydrogen; iii. The purified exhaust stream enters a second separation system in fluid communication with the first separation system; iv. Hydrogen is separated from the purified exhaust stream, thereby producing another hydrogen stream and a concentrated exhaust stream containing acetylene gas; v. The concentrated exhaust stream is delivered to a VCM reactor in fluid communication with the second separation system; where: (a) The VCM reactor receives the concentrated exhaust stream and directs the concentrated exhaust stream across a catalyst bed that reacts acetylene gas with a stream of hydrogen chloride gas to produce VCM; (b) The VCM reactor discharges the VCM formed therein into a gaseous VCM-containing exhaust stream that is directed to a third separation system; vi. The third separation system in fluid communication with the VCM reactor is a compression system that includes a compressor, a refrigeration chamber, and a liquid-gas separator, and the third separation system is adapted to compress the liquid VCM, separate it from the VCM exhaust stream, and produce a liquid VCM product and a residual gas stream.

[0029] Also described is a method of making vinyl chloride monomer using the systems described herein. In one aspect, the invention relates to a method for making vinyl chloride monomer, the method comprising the steps of providing a system as described herein; treating a hydrocarbon-containing inlet gas to produce an outlet gas product, wherein the outlet gas product contains acetylene and hydrogen, and the treating step comprises injecting the hydrocarbon-containing inlet gas into a plasma reaction chamber; supplying microwave energy to the hydrocarbon-containing inlet gas in the plasma reaction chamber to generate a plasma; forming an outlet gas product in the plasma, wherein the outlet gas product contains acetylene and hydrogen; flowing the outlet gas product out of the plasma reaction chamber; and treating the acetylene produced in a VCM reactor and a separator subsystem in fluid communication with the plasma reaction chamber thereby, wherein the VCM reactor combines acetylene and hydrogen chloride gas to form VCM in the gas by a catalytic reaction within the VCM reactor, and the catalytic reaction proceeds by exposing acetylene and hydrogen chloride gas to a catalyst within the VCM reactor.

[0030] The present invention also includes a method for converting a hydrocarbon-containing feed gas into a VCM (vinyl chloride monomer)-containing liquid product, the method comprising: providing one or more gases, where the one or more gases include a hydrocarbon-containing feed gas; directing the one or more gases to the system described herein, where a delivery conduit delivers the one or more gases to a gas injector, the gas injector delivers the one or more gases to a plasma reaction chamber, and a microwave subsystem directs microwave energy to the plasma reaction chamber to convert the one or more gases into a plasma, the plasma performing the conversion of hydrocarbons in the hydrocarbon-containing feed gas into an effluent gas product; the effluent gas product flows toward the distal end of an elongate reactor tube within the plasma reaction chamber, exits from the distal end of the elongate reactor tube, and forms an exhaust stream that enters a VCM reactor and a separator subsystem; the effluent gas product includes acetylene and hydrogen; the VCM reactor and separator subsystem are in fluid communication with the elongate reactor tube; combining acetylene and hydrogen chloride within the VCM reactor to form a VCM-containing gas; and separating VCM from the VCM-containing gas as a VCM-containing liquid product.

[0031] In yet a further aspect, the present invention includes a method for treating a hydrocarbon-containing feed gas into a VCM (vinyl chloride monomer)-containing liquid product, the method comprising: injecting the hydrocarbon-containing feed gas into a plasma reaction chamber; supplying microwave energy to the hydrocarbon-containing feed gas in the plasma reaction chamber to generate a plasma; forming an effluent gas product in the plasma, where the effluent gas product includes acetylene and hydrogen; flowing the effluent gas product out of the plasma reaction chamber and into a VCM and separator subsystem, where the VCM and separator subsystem is in fluid communication with the plasma reaction chamber, the VCM and separator subsystem includes a VCM reactor, and the effluent gas product includes acetylene and hydrogen; combining acetylene and hydrogen chloride within the VCM reactor to form a VCM-containing gas; and separating VCM from the VCM-containing gas as a VCM-containing liquid product.

[0032] The present invention also encompasses an integrated acetylene - based vitamin synthesis system for synthesizing vitamin products (including, but not limited to, vitamin A, vitamin E, β - carotene, or combinations thereof) that includes a plasma - based hydrocarbon treatment system and a vitamin production system, wherein the plasma - based hydrocarbon treatment system includes a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and a set of separator subsystems, The gas delivery subsystem: i. is in fluid communication with the plasma reaction chamber and directs one or more gases into the plasma reaction chamber, where the one or more gases include a hydrocarbon - containing inlet gas; and ii. includes a delivery conduit and a gas injector, a. where the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers one or more gases to the gas injector, and the delivery conduit includes a supply gas transport circuit that delivers the hydrocarbon - containing inlet gas to the gas injector, b. the gas injector delivers one or more gases into the plasma reaction chamber; The plasma reaction chamber: i. is in fluid communication with an effluent separation and disposal system; ii. is disposed within an elongated reactor tube having proximal and distal ends, and the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem; The microwave subsystem: i. directs microwave energy into the plasma reaction chamber to energize the hydrocarbon - containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma effects the conversion of hydrocarbons in the hydrocarbon - containing inlet gas to an effluent gas product, and the effluent gas product includes acetylene and hydrogen; ii. includes an applicator for directing microwave energy into the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of the elongated reactor tube that passes through and intersects the applicator perpendicularly; and iii. Further comprising a power source, a magnetron, and a waveguide, wherein the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is transported by the waveguide to the applicator, and the applicator directs the microwave energy into the reaction chamber within the elongated reactor tube, thereby forming a plasma in the plasma reaction chamber. Here, the effluent gas product flows towards the distal end of the elongated reactor tube within the plasma reaction chamber, exits from the distal end of the elongated reactor tube, and forms an effluent stream that enters a set of separator subsystems. i. Here, the set of separator subsystems includes an effluent separator, an acetylene separator, and a hydrogen separator. ii. The effluent separator is in fluid communication with the elongated reactor tube and is adapted to remove higher acetylenes and aromatics from the effluent stream to produce a purified effluent stream containing acetylene gas and hydrogen. iii. The acetylene separator is in fluid communication with the effluent separator, separates the purified acetylene product from the purified effluent stream, thereby forming a residual effluent stream, and the acetylene separator is in fluid communication with the vitamin production system and directs at least a portion of the purified acetylene product to the vitamin production system. iv. The acetylene separator is further in fluid communication with the hydrogen separator and directs the residual effluent stream to the hydrogen separator, and the hydrogen separator separates hydrogen from the residual effluent stream to produce a purified hydrogen product. v. The hydrogen separator is also in fluid communication with the vitamin production system and directs at least a portion of the purified hydrogen product to the vitamin production system; and Here, the vitamin production system includes a vitamin reaction plant and a controller, and the controller controls the entry of a portion of the purified acetylene product and a portion of the purified hydrogen product into the vitamin reaction plant. The vitamin reaction plant synthesizes vitamin products using the purified acetylene product and / or the purified hydrogen product.

[0033] The present invention also includes a method for synthesizing a vitamin product, including the use of an integrated acetylene-based vitamin synthesis system for synthesizing the vitamin product. In certain embodiments, the method of the present invention comprises: i. treating a hydrocarbon-containing inlet gas using the system described herein to produce an outlet gas product, wherein the outlet gas product comprises acetylene and hydrogen, and wherein the treating step comprises: a. injecting the hydrocarbon-containing inlet gas into a plasma reaction chamber; b. supplying microwave energy to the hydrocarbon-containing inlet gas in the plasma reaction chamber to generate a plasma; c. forming an outlet gas product in the plasma, wherein the outlet gas product comprises acetylene and hydrogen; d. flowing the outlet gas product out of the plasma reaction chamber; and comprising; ii. separating the outlet gas product into a set of gas streams, wherein the set of gas streams comprises a first gas stream comprising higher acetylenes and aromatic impurities, a second gas stream comprising purified acetylene, and a third gas stream comprising purified hydrogen; iii. directing the second gas stream comprising purified acetylene to a vitamin production system; and iv. synthesizing a vitamin product from the purified acetylene; and comprising.

[0034] The present invention also encompasses an integrated acetylene-based synthesis system for synthesizing acetylene black, comprising a plasma-based hydrocarbon treatment system and an acetylene black production system: wherein the plasma-based hydrocarbon treatment system comprises a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and a set of separation and purification subsystems, wherein the gas delivery subsystem: i. is in fluid communication with the plasma reaction chamber and directs one or more gases to the plasma reaction chamber, wherein the one or more gases comprise a hydrocarbon-containing inlet gas; and ii. including a delivery conduit and a gas injector, wherein the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers one or more gases to the gas injector, the delivery conduit includes a supply gas transport circuit that delivers a hydrocarbon-containing inlet gas to the gas injector, the gas injector delivers one or more gases to the plasma reaction chamber; the plasma reaction chamber: i. is in fluid communication with an effluent separation and disposal system; ii. is disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with a microwave subsystem; the microwave subsystem: i. directs microwave energy to the plasma reaction chamber, supplies energy to the hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma performs the conversion of hydrocarbons in the hydrocarbon-containing inlet gas to effluent gas products, and the effluent gas products include acetylene and hydrogen; ii. includes an applicator for directing microwave energy to the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of the elongated reactor tube that passes through and intersects the applicator perpendicularly; and iii. further includes a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is transported by the waveguide to the applicator, and the applicator directs the microwave energy to the reaction chamber within the elongated reactor tube, thereby forming a plasma in the plasma reaction chamber, where the effluent gas products flow toward the distal end of the elongated reactor tube within the plasma reaction chamber, exiting the distal end of the elongated reactor tube to form an effluent stream that enters a set of separation and purification subsystems; i. Here, a set of separation and purification subsystems includes an acetylene separator in fluid communication with an elongated reactor tube, adapted to remove higher acetylenes and aromatics from the effluent stream to produce a purified effluent stream containing acetylene gas and hydrogen and an offgas stream containing higher acetylenes and aromatics; ii. The set of separation and purification subsystems further includes a hydrogen separator in fluid communication with the elongated reactor tube, the hydrogen separator separating hydrogen as a hydrogen stream from at least one of the effluent stream and the purified effluent stream; iii. The set of separation and purification subsystems produces an acetylene-rich feedstock stream; and An acetylene black production subsystem, where the acetylene black production system includes an acetylene decomposition reactor in fluid communication with the separation and purification subsystems, the acetylene decomposition reactor producing acetylene black and hydrogen from the acetylene-rich feedstock stream produced by the separation and purification subsystems.

[0035] The present invention also includes a method for synthesizing acetylene black, including the use of the integrated acetylene-based system described herein. In certain embodiments, the method of the present invention comprises: i. Providing the integrated acetylene-based system described herein; ii. Using the integrated acetylene-based system to process a hydrocarbon-containing inlet gas to produce an outlet gas product, where the outlet gas product contains acetylene and hydrogen, and where the processing step comprises: a. Injecting the hydrocarbon-containing inlet gas into a plasma reaction chamber; b. Supplying microwave energy to the hydrocarbon-containing inlet gas in the plasma reaction chamber to generate a plasma; c. Forming an outlet gas product in the plasma, where the outlet gas product contains acetylene and hydrogen; d. Flowing the outlet gas product out of the plasma reaction chamber including; iii. A step of separating the effluent gas product into a set of gas streams, where the set of gas streams includes a first gas stream containing higher acetylenes and aromatic impurities, a second gas stream containing purified acetylene, and a third gas stream containing purified hydrogen; iv. A step of directing the second gas stream containing purified acetylene to an acetylene black production system; and v. A step of synthesizing acetylene black from the purified acetylene is included.

[0036] The present invention further includes an integrated acetylene-based synthesis system for producing hydrogen, the system includes a plasma-based hydrocarbon treatment subsystem and an acetylene black production subsystem: a. Here, the plasma-based hydrocarbon treatment subsystem includes a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and a set of separation and purification subsystems, the gas delivery subsystem is: i. In fluid communication with the plasma reaction chamber, directing one or more gases to the plasma reaction chamber, where the one or more gases include a hydrocarbon-containing influent gas; and ii. Including a delivery conduit and a gas injector, where the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers one or more gases to the gas injector, and the delivery conduit includes a supply gas transport circuit for delivering the hydrocarbon-containing influent gas to the gas injector, the gas injector delivers one or more gases to the plasma reaction chamber; the plasma reaction chamber is: i. In fluid communication with a set of separation and purification subsystems; ii. Disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem; the microwave subsystem is: i. Direct microwave energy towards a plasma reaction chamber to supply energy to a hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma performs the conversion of hydrocarbons in the hydrocarbon-containing inlet gas to outlet gas products, and the outlet gas products include acetylene and hydrogen; ii. Include an applicator for directing microwave energy towards the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of an elongated reactor tube that passes through the applicator and intersects it perpendicularly; and iii. Further include a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, and the microwave energy is transported by the waveguide to the applicator, and the applicator directs the microwave energy towards the reaction chamber within the elongated reactor tube, thereby forming a plasma in the plasma reaction chamber, where the outlet gas products flow towards the distal end of the elongated reactor tube within the plasma reaction chamber, exit from the distal end of the elongated reactor tube, and form an outlet stream that enters a set of separation and purification subsystems; where the set of separation and purification subsystems is: i. Include an effluent separator in fluid communication with the elongated reactor tube to remove higher acetylenes and aromatics from the outlet stream, producing (a) a purified effluent stream containing acetylene gas and hydrogen and (b) an offgas stream containing higher acetylenes and aromatic impurities; ii. Further include an acetylene separator in fluid communication with the effluent separator to produce an acetylene-rich feedstock stream and a residual effluent stream as separated streams; iii. Further include a hydrogen separator in fluid communication with the acetylene separator, where the hydrogen separator separates hydrogen as a purified hydrogen stream from the residual effluent stream, 1. where the hydrogen stream is separable into one or more of a recycled hydrogen stream, an integrated hydrogen stream, and an external hydrogen stream, 2. the external hydrogen stream is isolated from an acetylene-based synthesis system integrated as a first isolated hydrogen stream; and b. Here: i. The acetylene black production system includes an acetylene decomposition reactor in fluid communication with a set of separation and purification subsystems; ii. The acetylene decomposition reactor produces acetylene black and hydrogen from an acetylene-rich feedstock stream, iii. The hydrogen produced by the acetylene decomposition reactor is separable from an acetylene-based synthesis system integrated as a second isolated hydrogen stream.

[0037] The present invention also encompasses a method for producing hydrogen, the method comprising: a. Providing the integrated acetylene-based synthesis system as described above, b. Treating a hydrocarbon-containing inlet gas using a plasma-based hydrocarbon treatment subsystem to produce an outlet gas product, where the outlet gas product contains acetylene and hydrogen, and the treatment process comprises: i. Injecting the hydrocarbon-containing inlet gas into a plasma reaction chamber; ii. Supplying microwave energy to the hydrocarbon-containing inlet gas in the plasma reaction chamber to generate a plasma; iii. Forming an outlet gas product in the plasma, where the outlet gas product contains acetylene and hydrogen; iv. Flowing the outlet gas product out of the plasma reaction chamber including; a. Separating the outlet gas product into a set of gas streams, where the set of gas streams includes a first gas stream containing higher acetylenes and aromatic impurities, a second gas stream that is a purified hydrogen stream, and a third gas stream that is an acetylene-rich feedstock stream; the step of separating the outlet product further includes a sub-step of discharge separation for removing higher acetylenes from the first gas stream and a step of acetylene separation for removing purified acetylene from the third gas stream; b. Isolating at least a portion of the purified hydrogen stream as a first isolated hydrogen stream; c. Directing the acetylene-rich feedstock stream to the acetylene black production subsystem to produce hydrogen and acetylene black therefrom; and d. Isolating at least a portion of the hydrogen from step e as a second isolated hydrogen stream including.

[0038] In one aspect, the systems and methods described herein further include a vacuum subsystem that maintains a first reduced pressure environment for the effluent product passing through one or more components of the emissions separation and disposal subsystem. The vacuum subsystem may create a second reduced pressure environment within an elongated reactor tube and / or the vacuum subsystem may create a third reduced pressure environment for the gas delivery subsystem. In an aspect, the vacuum subsystem creates the first, second, and third reduced pressure environments; in an aspect, the first, second, and third reduced pressure environments are in the range of about 30 to about 120 Torr. In an aspect, at least one of the reduced pressure environments is about 50 to about 100 Torr or about 60 to about 80 Torr. In an aspect, the first, second, and third reduced pressure environments are substantially similar. The pressures in the first, second, and third reduced pressure environments are "substantially similar" when the respective pressures differ by less than about 10% or less than about 5%. For example, if the pressure in the first reduced pressure environment is 70 Torr, the pressure in the second reduced pressure environment is 67 Torr, and the pressure in the third reduced pressure environment is 70 Torr, the pressures are substantially similar. In an aspect, the first reduced pressure environment has a pressure that is substantially higher than the pressure in the second and / or third reduced pressure environments. The pressure in the first reduced pressure environment is "substantially higher" than the pressure in the second and / or third reduced pressure environments when the pressure in the first reduced pressure environment is at least about 10% higher or at least about 15% higher or at least about 20% higher than the pressure in the second and / or third reduced pressure environments. In one aspect, the first reduced pressure environment has a pressure of about 120 to about 280 Torr. In a further aspect, the second and / or third reduced pressure environments have pressures in the range of about 120 to about 280 Torr, while the first reduced pressure environment may have a pressure within the same range or higher. In an aspect, the system further includes a cooling subsystem. The cooling subsystem may include at least one of a water cooling subsystem and a gas cooling subsystem.In an aspect, the gas cooling subsystem includes a nitrogen-based cooling circuit, which may include one or more enclosures for components of the system. The one or more enclosures are sufficiently sealed to confine nitrogen around the components and exclude oxygen therefrom. In an aspect, the system includes a data management and safety subsystem.

Brief Description of the Drawings

[0039] Brief Description of the Drawings

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DETAILED DESCRIPTION OF THE INVENTION

[0040] Detailed Description Systems and methods for converting C1-C4 hydrocarbons, such as unsaturated hydrocarbons and saturated hydrocarbons such as methane (e.g., from a mixed gas source such as natural gas or biogas), into hydrogen, acetylene, and other carbon-based products are disclosed in more detail herein. In aspects, these systems and methods use non-thermal plasma generated by microwave energy to perform these conversions. In aspects, the systems and methods disclosed herein can be optimized ( "tuned") to maximize the efficient production of acetylene or hydrogen as products that can be isolated for further commercialization; in other aspects, these systems and methods can be tuned to produce combinations of these gases for specific industrial purposes.

[0041] 1. Overview a. Non-thermal Plasma Plasma, the fourth state of matter, is an ionized gas: any gas can be converted into plasma by applying sufficient energy to it to create a significant density of charged species, namely electrons and ions. Plasma has some of the properties of a gas, but it differs from the normal gaseous state because it responds to both electric and magnetic fields, which are characteristics of the charged species present in the plasma state. Despite having these characteristics, plasma is electrically neutral and has a characteristic so-called quasi-neutrality. In addition to the ions and free electrons derived from the precursor gas present in the plasma, the plasma contains uncharged neutral gas species and precursor molecules that can enter into other chemical reactions. Some weakly ionized gases do not necessarily meet all of the conditions of a plasma, but can still have many plasma-like properties that affect their behavior. For example, many of the high-pressure plasmas used in industrial applications fall into this category.

[0042] One of the basic characteristics of plasma is its temperature. Since plasma can generate a much higher temperature than that obtained in conventional chemical engineering processes, it is used in chemical and industrial applications. In plasma, energy is transferred to electrons, which then transfer the energy to heavier particles through collisions. Electrons have a higher temperature than heavier particles and reach an equilibrium temperature that reflects the collision frequency and radiation processes of various particles in the plasma. These plasmas, which have an electron temperature (T e ) close to the translational temperature (T0) of the heavier particles, are defined as thermal plasmas, and the gas temperature is higher than 3,000K. In contrast, in non-thermal plasmas, high-energy electrons can coexist with species that have a substantially lower temperature. Therefore, the translational temperature T0 of non-thermal plasmas can be much lower than the electron temperature T e of the plasma, and T e can be close to 11,600K in industrial plasmas or even higher in other types of plasmas.

[0043] The energy situation of plasma is more complex when the plasma contains molecules (such as H2, N2 or CH4) instead of just atoms. Since these molecules have the ability to store energy during various rotational and vibrational motions, they have associated rotational and vibrational temperatures. These temperatures for such plasmas are generally between the translational and electron temperatures of the plasma and can affect the behavior of the plasma and its associated chemistry. The techniques disclosed herein are based on the ability of non-thermal plasmas to transfer most of the electrical input energy to energetic electrons in the constituent feed gas rather than heating the gas itself. Through electron collisions, ionization, dissociation and excitation, charged atomic and molecular species (such as electrons, ions, radicals) that can participate in chemical reactions are generated.

[0044] Methane is particularly resistant to chemical conversion due to its stability: the breaking of the C-H bonds in methane is 1664 kJ mol -1requires an enthalpy change. Using the techniques described below, non-thermal plasmas can be created and utilized to break bonds in C1-C4 hydrocarbons such as methane, and acetylene and hydrogen molecules with high effectiveness and selectivity can be generated.

[0045] b. Microwave plasma generation In an embodiment, the plasma used in these systems and methods is a microwave plasma formed by directing microwave energy with a methane-containing feed gas, as described in more detail below. Methane is used as an exemplary embodiment of this description, but it is understood that other short-chain alkanes (e.g., ethane, propane, butane) can also be used as the feed gas, either as a single gas feed gas or in combination with each other or with methane.

[0046] The microwave plasma processes described herein are gas-phase processes that use gaseous reactant precursors to form the desired gaseous products. Due to the very fast electric field oscillation frequency compared to the molecular and electron collision frequencies, microwave-generated plasmas are often highly non-equilibrium, meaning that the electron and vibrational temperatures can be significantly higher than the gas temperature. In an embodiment, collisions between charged species (electrons, ions) and neutral species (molecules, atoms, particles) in the microwave plasma transfer energy: this microwave energy-supplied plasma supports a highly reactive chemical environment due to the energy contained in the free electrons of the plasma. Due to the high ionization of the precursor gas, chemical ionization and ionization of intermediates, and high vibrational and excitation energies in the plasma, the desired chemical reactions described below proceed rapidly and efficiently.

[0047] Without being bound by theory, microwave radiation is understood to act as follows to generate a plasma from a gaseous precursor. When a precursor gas (e.g., methane) is subjected to microwave radiation that meets or exceeds the dielectric strength of such gas, free electrons (presented from background radiation or other sources) in the microwave field region can acquire sufficient energy from the microwave electric field during collisions with neutral molecules that can ionize another atom or molecule. The secondary ionized electrons are then accelerated in a direction dominated by the electric field of the microwave radiation, and the electrons also acquire energy until another ionization event is caused. This process of ionization proceeds throughout the microwave field region until a stable state is achieved. The final number of electrons in the plasma is mainly determined by the electron loss processes of the plasma such as diffusion, recombination, and attachment.

[0048] The systems and methods disclosed herein use C1-C4 hydrocarbons such as methane as the reactant precursor gas subjected to microwave radiation. Methane can be used to exemplify the reactant precursor gas suitable for use in these systems and methods.

[0049] Methane ionization in the plasma initiated by collisions with electrons supplied with energy as described above results in the formation of CH x radicals. The main initial reaction is the cleavage of the C-H bond in methane, resulting in the formation of CH3*, CH2*, CH*, H*, and C. These radicals can recombine to form two-carbon fragments as exemplified by the following equations: CH3* + CH3* → C2H6 CH2* + CH2* → C2H4 CH* + CH* → C2H2 CH3* + CH* → C2H4 CH3* + CH2* → C2H4+ H* CH3* + CH* → C2H4 CH3* + CH* → C2H2+ H2 CH2* + CH* → C2H2+ H*

[0050] In addition, methane can combine with various radicals to form a two-carbon fragment as exemplified by the following equations: CH4 + CH3* → C2H6 + H* CH4 + CH2* → C2H6 CH4 + CH2* → C2H4 + 2H* / H2CH4 + CH* → C2H4 CH4 + CH* → C2H2 + H* + H2

[0051] In addition to the illustrated reactions that form two-carbon fragments and hydrogen, higher hydrocarbons can be formed by the recombination of plasma-generated radicals with each other and with the precursor gas. As used herein, the term "higher hydrocarbon" refers to any hydrocarbon having three or more carbon atoms, whether saturated or unsaturated and including aromatics.

[0052] Furthermore, complete dehydrogenation of methane can occur, resulting in the formation of elemental carbon and hydrogen gas. Representative reactions are shown in FIG. 1. As shown in FIG. 1, some exemplary reactions for making hydrocarbons are shown within the dotted line, while the elemental products (hydrogen and carbon) are shown outside the dotted line.

[0053] In some embodiments, the parameters can be optimized to maximize acetylene formation. In other embodiments, the parameters can be optimized to maximize hydrogen formation. As a general principle, for example, if the feed gas entering the plasma reaction chamber contains less hydrogen compared to the hydrocarbon input, the output is potentially more hydrogen formed in combination with more carbon solids. In accordance with this principle, to maximize hydrogen formation, a pure hydrocarbon feed can be used, producing more of the desired hydrogen along with the amount of carbon solids. Factors that can affect product selectivity (e.g., enabling preferential formation of acetylene over other species or enabling preferential formation of hydrogen over hydrocarbon products) include, without limitation, the identity of the reactant precursor gas, addition of other gases to the system, the flow rate of any gas entering the system, the temperature and pressure within the reactor system, the amount of microwave power and flow geometry used to generate the plasma, the energy density of the reaction zone, the arrangement of the electric field around the plasma, as well as the reactor vessel geometry and dimensions. In some embodiments, static and magnetic fields can be used to affect the behavior of the plasma and thereby product selectivity.

[0054] c. Precursor gas For the systems and methods disclosed herein, C1-C4 alkane hydrocarbons (e.g., methane, ethane, propane, and butane) or other hydrocarbon gases can be used as the precursor gas alone or in combination with other gases. In some embodiments of these systems and methods, methane is the primary precursor gas. In some embodiments, methane can be combined with hydrogen and / or nitrogen when entering the plasma reaction chamber to form a single gas mixture that is energy-supplied to the plasma state. In some embodiments, methane enters the plasma reaction chamber through its own set of nozzles, while other gases (e.g., hydrogen and / or nitrogen) are added separately to the plasma reaction chamber through different sets (one or more) of nozzles. Methane can be used in a pure state or introduced into the system as a component of a commercially available gas stream.

[0055] A mixed gas supply source such as natural gas or biogas is a particularly advantageous supply source for this precursor gas. As used herein, the term "biogas" refers to a mixed gas produced by the anaerobic decomposition of organic waste in various natural or artificial environments; the term "biogas" includes all these natural or artificial environments in which such gas-producing anaerobic decomposition can occur, such as landfills, manure holding ponds, municipal waste sites, sewage treatment facilities, agricultural waste sites, permafrost degradation, etc. Biogas collected or recovered from these locations can be treated or upgraded to increase its methane content and remove impurities, making it particularly suitable as a precursor gas for the systems and methods disclosed herein.

[0056] Biogas made from feedstocks such as municipal waste, agricultural waste, plant material, sewage, manure, food waste, or other natural or artificial organic sources is typically formed in a closed system by the anaerobic digestion or fermentation of organic materials. The first stage of this process is hydrolysis, which breaks down insoluble organic polymers into sugars and amino acids that serve as substrates for the activity of anaerobic acid-forming bacteria. In the second stage, these bacteria convert the sugars and amino acids into carbon dioxide, hydrogen, ammonia, and organic acids; the acid-forming bacteria further convert the organic acids into acetic acid, ammonia, and carbon dioxide. As a third stage, another population of anaerobic bacteria, the methanogenic microorganisms, convert these fermentation products into methane and carbon dioxide. Biogas containing a mixture of methane and carbon dioxide along with gaseous by-products such as hydrogen sulfide can be collected and treated to remove carbon dioxide and undesirable gaseous products, leaving a gaseous mixture with a high concentration of methane suitable for energy generation or further processing. The methane in biogas is concentrated using the biogas upgrading process, resulting in a product with performance characteristics similar to those of fossil-derived natural gas.

[0057] Processes such as water washing, adsorption, membrane separation, amine gas treatment, etc. can be used for biogas upgrading. The upgrading process can be advantageously carried out to remove oxygen from biogas before using the biogas as a gas source. Oxygen in the feed gas can make the feed gas vulnerable to combustion; furthermore, oxygen can corrode the equipment used in the plasma-based hydrocarbon treatment system disclosed herein. Additionally, under certain circumstances, oxygen removal may be necessary to meet regulatory standards or other purity requirements. Some oxygen removal techniques are suitable for use with biogas. By way of example, oxygen can react with reduced metal species, oxidizing the metal in such a way and consuming the oxygen. The oxidized metal species are then regenerated to an active form by passing a hydrogen or carbon monoxide-containing gas stream over the metal species, generating water or carbon dioxide respectively to reduce the metal species. Metal species such as palladium or nickel could have been used to catalytically combust oxygen at >500°F using hydrocarbon species mixed with O2. As another approach, disposable solid scavengers can be used to trap oxygen. For example, Fe2S3 can react with 3 molar equivalents of molecular oxygen to form rust and elemental sulfur. As yet another approach, oxygen can be separated from other gases by molecular sieves such as 5A or 13X molecular sieves, similar to the techniques found in air separation units (ASUs). Other upgrading processes for biogas are available to those skilled in the art using routine experimentation below. The upgraded biogas can achieve a purity and quality similar to that of natural gas in U.S. pipelines and can be used for the same purposes.

[0058] Natural gas extracted from the earth is mainly methane, making methane a useful source of precursor gas for these systems and methods. Typically, it also contains higher hydrocarbons such as ethane, propane, butane, and pentane, along with non-hydrocarbon impurities. The following table (Table 1) shows an exemplary composition of natural gas.

Table 1

[0059] Natural gas is generally processed to remove most non - methane components before it can be made available for commercial or residential use, so that it is almost pure methane when it reaches the consumer. As an example, commercially available natural gas can contain about 96% methane. To transport natural gas to the consumer market after removing its impurities, there are large - scale pipeline systems in the United States, but much natural gas is discovered far from these markets and in areas remote from pipeline infrastructure (often referred to as remote or "stranded" natural gas). In an aspect, the systems and methods disclosed herein can be used in - place, for example, at the location of stranded natural gas, to convert it into acetylene and other suitable products; thus these systems and methods provide a cost - effective way to use this stranded natural gas as a feedstock.

[0060] 2. Systems and Subsystems In an aspect, the plasma - based hydrocarbon processing system disclosed herein can include six subsystems: 1) a gas delivery subsystem, 2) a microwave subsystem, 3) a vacuum subsystem, 4) a cooling subsystem, 5) an effluent separation and disposal subsystem, and 6) a data management and safety subsystem. These subsystems are described in more detail below. The integration of these subsystems is schematically shown in FIG. 2. The desired outputs from these subsystems and methods can include high - level methane conversion and high - level acetylene selectivity and / or high - level hydrogen selectivity.

[0061] As schematically shown in FIG. 2, the plasma-based hydrocarbon treatment system 200 provides for the conversion of one or more inlet gases 202, 204, and 208 into a gaseous product mixture contained in the effluent stream 212 exiting the plasma reaction chamber 214, where the plasma reaction chamber contains a plasma generated by the microwave subsystem 218. In the illustrated embodiment, the hydrocarbon inlet gas 202, such as methane, enters the plasma reaction chamber 214 separately from the hydrogen-containing inlet gas 208 resulting from the recirculation of a particular fraction of the effluent stream 212. Any auxiliary gas 204, such as nitrogen, can be introduced separately as shown or can be mixed with one or both of the other inlet gases 202 and 208. The various inlet gas flows and their directions to the plasma reaction chamber 214 are included in the gas delivery subsystem 210. The gas delivery subsystem 210 is responsible for creating the appropriate ratios of inlet gases and controlling their flow rates. Once the inlet gases enter the plasma reaction chamber 214, they are energized by microwaves generated by the microwave subsystem 218 that create a plasma state within the plasma reaction chamber 214. The effluent stream 212 carries an effluent (or “produced”) gaseous product containing acetylene, hydrogen, and a mixture of unreacted methane and higher hydrocarbons. Carbon solids can be included in the effluent gas stream 212. The exhaust separation and disposal subsystem 220 enables the separation of waste components from the effluent stream 212 so that they can be disposed of and further enables the separation of desired components to another stream if necessary for further commercialization or reintroduction to the plasma reaction chamber 214 as the inlet gas 208. For example, acetylene 224 can be separated from the effluent stream 212 in the separation / disposal subsystem 220 and can be used commercially. In an embodiment, for example, acetylene can be further purified for use in chemical reactions. In other embodiments, acetylene can be further processed either to form other compounds or elemental carbon for other uses or for disposal. In an embodiment, the carbon solids contained in the effluent gas stream 212 can be removed by the separation / disposal subsystem 220 as another product or waste material 222.In the illustrated embodiment, the recycled stream 228, which is primarily hydrogen, exits the separation / disposal subsystem and is recycled as the influent gas 208 into the plasma reaction chamber 214. In other embodiments, some or all of the hydrogen produced by the reactor can be separated from the effluent stream 212 and can be commercialized separately. In yet other embodiments, the separation of the effluent stream 212 components proceeds separately: for example, carbon can be completely separated, and the mixed hydrogen and hydrocarbon gas streams are separated for commercialization or other uses. The separation / disposal subsystem can be configured to separate a single gas or gas mixture according to specific gas treatment goals. As schematically shown in FIG. 2, the vacuum subsystem 230 is around certain system components to maintain them at low pressure. A cooling subsystem (not shown) provides appropriate cooling to each system component.

[0062] In embodiments, some system parameters can be modified to optimize hydrocarbon (e.g., methane) conversion rate and acetylene or hydrogen selectivity, such as the influent gas flow rate (SLM), influent pressure, and power per converted hydrocarbon (e.g., methane). Tables 2a and 2b show the effects of changes in these parameters in several different examples. A useful metric for comparing the results of different system parameters is the efficiency calculated as the energy (eV / CH4) used per molecule of converted methane. This metric is easily applicable to both industrial applications, such as production cost per kilogram of product, and scientific applications, such as comparison of bond strength and calculation of thermodynamic efficiency.

Table 2A

Table 2B

[0063] a. Gas Delivery Subsystem In an aspect, the gas delivery subsystem is configured to direct an inflow gas toward the plasma reaction chamber. The gas delivery subsystem includes two components, a delivery conduit and a gas injector. (i) The gas supplied to the reactor (inflow gas); (ii) a delivery conduit for transporting the inflow gas to the plasma reaction chamber, where the delivery conduit includes one or more other circuits (or "transport circuits") for gas flow, the transport circuits including a primary supply gas transport circuit, an auxiliary gas transport circuit for additional gases of the primary supply gas, and / or a recirculation gas transport circuit that enables the return of one or more generated gases (such as hydrogen) to be used as the inflow gas for subsequent reactions, and (iii) further description of the delivery conduit that introduces the component inflow gas into the plasma reaction chamber itself and the gas injector assembly in fluid communication with its component transport circuits is included in the description of this subsystem.

[0064] i. Inflow gas The inflow gas may include precursor reactant gases, such as C1-C4 alkane hydrocarbons in various combinations. The precursor reactant gas provides hydrogen or carbon for further reactions in the plasma state. In an aspect, the inflow gas is methane and hydrogen, and nitrogen is optionally combined with methane. In certain aspects, methane and hydrogen are reactants. The ratio of the reactant gas with any nitrogen additive can be empirically varied to optimize the product profile and yield.

[0065] The inlet gas used in the plasma-based hydrocarbon treatment system can be supplied directly from a supply tank, supply line, and / or by recirculation. As used herein, the term "inlet gas" means any gas added to the plasma reaction chamber in which the plasma is formed. As described in FIG. 1, the inlet gas can be a reactant gas such as methane or hydrogen that is converted into various products by the plasma state. The inlet gas can be an auxiliary additional gas, such as nitrogen. The inlet gas can be supplied from an external gas supply source called a "supply line" or from in-system recirculation, where the gas produced by the system is wholly or partially reintroduced into the plasma reaction chamber for subsequent reactions.

[0066] The inlet gas entering the system via an external gas supply source or supply line can be derived from a gas reservoir such as a storage tank or from an extrinsically located flowing gas line such as a mixed gas supply source line (e.g., a natural gas line or a biogas line). In an aspect, the inlet gas contains only (or substantially only) the reactants methane and hydrogen, and no additional gaseous additives are deliberately added. Methane in the inlet gas can be obtained as a component of a more complex flowing gas mixture such as natural gas or biogas. In an aspect, methane and optionally nitrogen are supplied from a supply line (i.e., a storage tank or a flowing gas line), and hydrogen can be supplied from a storage tank or recirculated from the product stream and directed back to the reactor.

[0067] The recirculation gas stream used for in-system recirculation is the effluent (i.e., the outflow gas) from the plasma reaction chamber, optionally separated into various component gases, and some or all of these gases are reintroduced into the plasma reaction chamber. In an aspect, hydrogen in the effluent gas product stream is separated from other gases and recycled in a purified form. In an aspect, the hydrocarbon inlet gas is introduced into the plasma reaction chamber via a flowing gas supply line, such as a natural gas line or a biogas line, and hydrogen is introduced into the plasma reaction chamber separately from the hydrocarbon inlet; this hydrogen may be derived in whole or in part from the recirculation gas stream.

[0068] In an embodiment, the recycle gas may include a hydrogen-rich reactant gas, where hydrogen is the main component and there are also some hydrocarbons that can react. In an embodiment, the recycle gas includes a hydrogen-rich reactant gas, and the hydrogen-rich reactant gas in the recycle gas is in an amount of 80% or more or about 85% or more or about 90% or more or about 95% or more of the recycle gas. The hydrogen-rich reactant gas may consist essentially of hydrogen, i.e., it may contain about 95% hydrogen or more or about 96% hydrogen or more or about 97% hydrogen or more or about 98% hydrogen or more or about 99% hydrogen or more. In an embodiment, the hydrogen-rich reactant gas includes about 90% or more or about 91% or more or about 92% or more or about 93% or more or about 94% or more of the recycle gas. In an embodiment, the recycle gas consists essentially of a hydrogen-rich reactant gas, i.e., the hydrogen-rich reactant gas includes about 95% or more or about 96% or more or about 97% or more or about 98% or more or about 99% or more of the recycle gas. In an embodiment, the recycle gas includes an inert gas such as nitrogen in addition to the hydrogen-rich reactant gas. In an embodiment, the amount of hydrogen in the recycle gas can be in an amount of 80% or more, 85% or more, 90% or more or 95% or more.

[0069] In an embodiment, the remainder of the recycle gas other than the hydrogen-rich reactant gas is nitrogen. In other embodiments, nitrogen is added as a separate auxiliary gas distinct from its presence or absence in the recycle gas. The volumes of hydrogen and nitrogen used in the system can be expressed in terms of the total methane flow. For example, the following ratios of the inlet gas feed: 1:0 to 3:0.1 methane:hydrogen:nitrogen can be used; in other embodiments, the following ratios of the inlet gas feed: 1:1 to 2:0.1 methane:hydrogen:nitrogen can be used. In an embodiment, similar ratios of methane and hydrogen can be used in the absence of nitrogen. In one embodiment, a methane flow of 300 - 400 SLM (about 11 - 14 SCFM) to the reactor can be used. In one embodiment, a methane flow of about 380 SLM (13.4 SCFM) can be used. In an embodiment, these flows are appropriate for a 100 kW reactor power.

[0070] In an embodiment, the amount of hydrogen inlet gas can be varied to select for more or less acetylene production. Increasing the amount of hydrogen entering the reactor increases the amount of this gas available to react with methane, thereby improving the conversion selectivity for acetylene production and reducing the amount of undesirable soot accumulation. In an embodiment, increasing the amount of hydrogen entering the reactor decreases the amount of ethylene in the effluent compared to acetylene.

[0071] In an embodiment, hydrogen is provided from a hydrogen cylinder. In other embodiments, hydrogen can be provided by recycling hydrogen produced by the system as a whole: i.e., hydrogen produced from a C1 - C4 hydrocarbon feedstock, such as methane during a plasma reaction, can be reused as a reactant. In one embodiment, a recycle gas transport circuit that returns hydrogen to the system as an inlet gas can be combined with another inlet source of hydrogen, such as from a hydrogen supply tank, to regulate the input of this gas. This approach can be advantageous at a particular time in the production cycle, such as at the start of the system when recycled hydrogen has not yet been produced, or to maintain a constant level of hydrogen inflow regardless of variations in the hydrogen produced during recycling.

[0072] In one aspect, the gas delivery subsystem may be pre-filled, for example, at the start of the system, to balance the mixing of gases and to harmonize gas flow and microwave energy. First, the system may be emptied and set to a pressure close to vacuum. Second, the system may be filled from an external hydrogen source either by backfilling through hydrogen introduced retrograde into the recirculation gas transport circuit or by front-filling from another hydrogen inflow line. Third, C1-C4 hydrocarbons (e.g., methane) or C1-C4 hydrocarbon / nitrogen mixtures may be added as the inflow gas and the flow is measured by a flow meter. Thus, using a pre-filled system with the appropriate gases, the reactor can be energized and the inflow gas can be processed. When the inflow gas is processed in the plasma reaction chamber, hydrogen is generated in the outflow gas product stream along with other gas products. The hydrogen captured from the outflow gas product stream can then be recycled to the system while simultaneously reducing the external hydrogen inflow. This balance of external and internal hydrogen inflows (from the external supply line and from recirculation) can facilitate a smooth start-up procedure for the overall system.

[0073] In an embodiment, methane is a major component of a hydrocarbon that comprises an influent gas for plasma-based hydrocarbon gas treatment described in these systems and methods. In an embodiment, methane can be introduced from a gas cylinder, from a pipeline, or from an influent of a mixed gas (e.g., natural gas or biogas) as previously described. A set of compressors can be used to introduce methane at an accurate pressure, e.g., a supply pressure of at least about 2 atm. When using natural gas or biogas to provide a methane feed gas, the amount of available methane can be monitored, e.g., using a bench-top gas chromatograph, and impurities in the natural gas can be identified and removed. For example, if a natural gas or biogas feed contains sulfur, the sulfur can affect the purity of the acetylene product stream; such impurities must be removed prior to treatment. Various impurities commonly found in natural gas or biogas (e.g., carbon dioxide, mercaptans, hydrogen sulfide, etc.) can be removed using a series of pre-scrubbers, where the type of scrubber selected depends on the impurities to be removed.

[0074] Desirably, the methane-containing gas mixture can contain a high concentration of methane, and thus it is substantially free of impurities or other gases. Natural gas directly derived from natural sources without commercial processing can contain about 90% or more methane. However, natural gas that is processed to be commercially available or biogas that is equivalently processed can substantially contain no non-methane gases and impurities. The hydrocarbon-containing inlet gas from such sources is presumed to consist essentially of methane, and such term refers to an inlet gas containing about 95% methane or more. Such a gas consisting essentially of methane can contain, for example, about 95% methane or more or about 96% methane or more or about 97% methane or more or about 98% methane or more or about 99% methane or more. Gases provided from natural sources such as in-situ natural gas (such as that found in mines before treatment) or biogas can contain a lesser amount of methane, but they can be pre-treated for use as a hydrocarbon-containing inlet gas so that such gases have a higher concentration of methane; in an aspect, when used as a hydrocarbon-containing inlet gas for these systems and methods, such pre-treated gases consist essentially of methane.

[0075] In an embodiment, other auxiliary gases can be used as components of the inflowing gas stream, such as additives like nitrogen, carbon dioxide and / or other reactive or inert gases. In one embodiment, nitrogen can optionally be used as a component of the inflowing feed gas; this can also be used as a sealing gas for a vacuum pump as described below. In one embodiment, the inflowing feed gas contains about 10% nitrogen, but this amount can be varied or adjusted to optimize the effectiveness and selectivity for the acetylene product; in other embodiments, nitrogen can be present in an amount in the range of about 0% to about 10%, and nitrogen is either deliberately added as a minor component of the accompanying feed gas or is present extraneously. In other embodiments, no additional nitrogen is included. In addition to its use as an inflowing gas component, nitrogen in gaseous and liquid form can be used as part of a cooling subsystem to cool various components and to provide a nitrogen “buffer” around the reactor as described below. Carbon dioxide can be included as another component of the inflowing gas, or it can be mixed into the reactor effluent and serve as an internal standard for gas chromatographic analysis of such effluent. In one embodiment, carbon dioxide is added to the effluent in an amount of 30% of the methane feed to achieve good accuracy in downstream gas chromatographic measurements. Other auxiliary gases, such as helium and argon for gas chromatography, can be used as inflowing gases along with the reactant gases.

[0076] ii. Gas delivery conduit The gas delivery conduit transports various inflowing gases (such as reactant gases, additive or auxiliary gases, and recirculation gases) to the gas injector; the gas injector delivers the various inflowing gases to the plasma reaction chamber. The gas delivery conduit includes transport circuits dedicated to specific gas flows: the feed gas is transported within the feed gas transport circuit, additional gases are transported by one or more additional gas transport circuits, and the recirculation gas(es) is / are transported by one or more recirculation gas transport circuits. In an aspect, these systems and methods use a hydrocarbon-bearing inflow stream, such as a methane stream or a mixed gas stream (such as natural gas or biogas), as the main gas feed, and the main gas feed is transported by the feed gas transport circuit. In an aspect, additional gas flows also pass through the gas delivery conduit along with the main gas feed, adding an inert gas such as nitrogen and / or adding a reactant such as hydrogen as a separate flow through their designated transport circuits. Further, in an aspect, the recirculation gas flow can be added to the mixture through the recirculation gas transport circuit as described in more detail below; the recirculation gas flow can include hydrogen as a dominant component along with nitrogen, minor amounts of other substances found in the natural gas feed, minor amounts of unreacted methane, and other hydrocarbon components produced by the plasma-based hydrocarbon processing system. In an aspect, each transport circuit is in fluid communication with the gas injector assembly and transports its gas separately to the gas injector assembly, for example, through dedicated nozzles, valves, or conduits.

[0077] A schematic diagram of an aspect of the gas delivery subsystem 300 according to these systems and methods is shown in FIG. 3. As shown in this figure, the hydrocarbon-bearing inlet gas stream 302 combines with the hydrogen-bearing inlet gas stream 304 and any auxiliary gas stream 308 and enters the plasma reaction chamber 310. In the aspect shown, the three gas streams enter a gas injector 312 (described in more detail below) that disperses the various streams in directions and at velocities such that a mixing of three separate flow vortices 314 occurs within the plasma reaction chamber 310. The gases mixed during the vortex mixing 314 enter the reaction region 318 of the plasma reaction chamber 310, where the gases are energized by microwave energy generated in the microwave subsystem 322 to form a plasma 320 within the reaction region 318 of the plasma reaction chamber 310. In the aspect shown, the inlet gases 302, 304, and 308 each enter the gas injector 312 as separate flows through separate inlets, and each enters the plasma reaction chamber 310 from its own outlet of the gas injector. The flow directions, flow velocities, and flow rates from each outlet are directed to cause a vortex mixing 314 of the gases within the plasma reaction chamber 310.

[0078] The inlet gas can be introduced into the plasma reaction chamber in a constant or variable flow pattern, in a continuous or discontinuous flow pattern, and in any combination of these patterns. In an aspect, the variable flow pattern can be regular or irregular in its variability, which can include intermittent pulses or surges of flow superimposed on the waveform underlying the flow pattern description. A sinusoidal flow pattern is an example of a variable flow pattern similar to a stepped or "boxcar" flow pattern using square waves that depict different amounts of flow profile. In an aspect, since these variable flow patterns can include periods of no flow, the variable flow pattern is discontinuous. In an aspect, the gas can be introduced simultaneously through all of the inlets, or the gas can be introduced at different times through different inlets. The gas can be introduced at different flow rates and in different flow patterns at each inlet. For example, the supply gas can be introduced continuously in a constant flow pattern, and one or more auxiliary gas flows can be introduced sporadically, i.e., discontinuously. Or, for example, the supply gas can be introduced discontinuously (i.e., with interruptions in its inflow), and one or more auxiliary gases can be introduced variably and / or discontinuously such that the auxiliary gas flows while the supply gas does not. Or as another example, the supply gas can be introduced continuously in a continuous flow pattern, and one or more auxiliary gas flows can be introduced continuously but in a different flow pattern than the supply gas. Other combinations of continuous / discontinuous patterns and flow pattern variability can be arranged to achieve specific gas treatment goals, such as to reduce soot formation in the plasma reaction chamber, or to increase acetylene selectivity, or to enable intermittent cleaning inside the reaction lumen.

[0079] As previously described, a gas that is energized to a plasma state experiences a spectrum of reactions in which a hydrocarbon feed gas is converted to other hydrocarbons and hydrogen. FIG. 3 shows an effluent stream 324 exiting the plasma 320 and containing the desired hydrocarbon product(s), certain exogenous hydrocarbon products, and hydrogen gas. The components of the effluent stream 324 are separated from each other by means of the previously described effluent separation / disposal system 328.

[0080] iii. Gas Injector The gas injector introduces various inflowing gas streams into the plasma reaction chamber through a plurality of inlets. In an aspect, a gas injector that includes flow channels for the various inflowing gas streams can be printed from a high temperature resin. This can be deployed within the reactor at a variable distance from or in fluid communication with the plasma reaction chamber within the reactor, where the term "plasma reaction chamber" refers to the region within the reactor where microwave energy encounters the feed gas stream. In one aspect, the gas injector can be disposed at the proximal end of the reactor, enabling a proximal-to-distal progression of gas flow along the long axis of the reactor. In other aspects, the gas injector can be disposed at the distal end of the reactor or at any other location along the long axis of the reactor. In an aspect, the gas injector is disposed at the center within the reactor tube and the gas flow is directed peripherally. In other aspects, the gas injector is disposed peripherally within the reactor tube and the gas flow is directed centrally. Since the gas flow exiting the nozzle can be directed at any angle along the long axis of the tube, the gas can flow axially proximally or distally. The nozzle can be arranged to produce a symmetric or asymmetric swirl flow.

[0081] In an aspect, the inflowing gas flow can be directed to the gas injector to produce a helical or swirling gas flow, which aids in mixing the various gas streams. The gas injector is configured to provide a separate nozzle or port for each such that the inflowing gas stream enters the reactor. The swirling flow can originate from a gas injector device disposed centrally within a reactor having two or more nozzles or ports, where each inflowing gas is delivered separately through its own subset of one or more nozzles or ports. In one aspect, these nozzles or ports disposed at the center of the reactor can be directed towards the periphery and angled to produce a desired gas flow pattern. In other aspects, the swirling flow can be produced by the gas flowing into the reactor through a gas injector having two or more nozzles or ports arranged along the periphery of the reactor, where each inflowing gas is delivered separately through another subset of its own of the two or more nozzles or ports. In an aspect, the swirling flow serves to confine the plasma towards the interior region of the reactor. Further swirling flow configurations such as reverse swirl flow can also be used as would be understood by one of ordinary skill in the art.

[0082] Figures 4A and 4B show aspects of a gas injector compatible with these systems and methods. FIG. 4A shows a cross-section of the proximal portion of the reaction chamber 402 of the plasma reactor 400, in which the gas injector 404 is centered; the approximate location of the cross-section shown in FIG. 4A is shown as line A in FIG. 3. The gas injector 404 shown in this FIG. 4A covers a central gas flow 408 and a second gas flow 410 that are coaxial but have different gas flows. The central gas flow 408 includes a main supply gas that may include one gas, such as methane, which is a main reactant. The second gas flow 410 includes a separate and distinct gas, such as a further gas or auxiliary gas such as hydrogen; this gas may also be a recycled gas such as hydrogen. Alternatively, the central gas flow 408 may include a further gas, and the second gas flow may include the main supply gas. In other aspects (not shown), the recycled gas flow may be maintained in a coaxial chamber separate from the flow channel for the auxiliary gas, and each flow channel has its own set of one or more gas nozzles entering the plasma reaction chamber 402. For the injector design shown in FIG. 4A, the central gas flow 408 is directed distally and is discharged from the gas injector 404 through the center of the central gas nozzle 412, which is only visible in cross-section here, and the second gas flow 410 is discharged from the gas injector 404 through the gas nozzles 412a and 412b directed towards the periphery. As shown in this figure, the second gas nozzles 412a and 412b are directed at an angle such that the second gas flows 414a and 414b enter the plasma reaction chamber 402 to form a vortex of gas within the reactor 400.

[0083] FIG. 4B shows a longitudinal cross-section of an embodiment of a gas injector 450 incorporating the principle shown in FIG. 4A. The gas injector 450 shown in FIG. 4B shows a coaxial arrangement of a central gas flow 452 surrounded by a second gas flow 454. The gas injector 450 is disposed centrally within a reactor (not shown), and the gas flows from the central gas flow 452 and the second gas flow 454 are discharged from the gas injector 450 and flow into the reactor. The second gas nozzles 458a and 458b may be arranged at an angle such that the second gas discharged from these nozzles is directed to create a swirling flow (seen in FIG. 4A). Similarly, the gas discharged from the first gas nozzle 460 may be directed to generate or contribute to a swirling flow. In an embodiment, the swirling flow created in the reactor 400 by the gas injector 450 may mix the gases and then optimize the exposure of the gas flow to the plasma.

[0084] b. Microwave Subsystem In an embodiment, the microwave subsystem includes various components used to generate, induct, and apply microwave power to form a non-thermal plasma that converts a feed gas into its products.

[0085] Schematic diagrams of aspects of the microwave subsystem are shown in FIGS. 5 and 6 below. FIG. 5 provides an overview of the components of the subsystem. As shown in FIG. 5, an aspect of the microwave subsystem 500 includes a power source 502, a magnetron 504, a waveguide assembly 508, and an applicator 510. The microwave energy generated by the magnetron 504 encounters an inflowing gas within a plasma reaction chamber 512 in an elongated reactor tube 514 (seen in cross section here), creating a plasma. The reactor tube 514 can be made of quartz, as described in more detail below. In one aspect, the power source 502 requires a 480 V, 150 A AC power source to generate low-ripple DC power of 20 kV, 5.8 A at 96% efficiency to power the magnetron. In one aspect, the magnetron 504, which is also evaluated at 100 kW, generates microwave power at an efficiency of 83 - 89%. In the aspect, the generated microwave is in the L band having a frequency of 915 MHz.

[0086] As shown in this figure, the microwave enters the waveguide assembly 508, which directs it to the applicator 510, which in turn directs the microwave to the plasma reaction chamber 512 in the reactor tube 514. In the illustrated embodiment, the waveguide assembly 508 includes two circulators 518 and 520, which direct the microwave to the applicator 510 and prevent the reflected microwave power from returning to and damaging the magnetron 504. Each circulator 518 and 520 includes a respective ferrite array 516 and 526 that deflects the reflected microwave to direct the reflected microwave to the applicator 510 and the plasma reaction chamber 512, as described in more detail below. Each circulator 518 and 520 has its respective water load 522 and 524 at its periphery to collect the reflected microwave. As shown, the second circulator 520 includes a power tuner 528 that uses a three-stub tuner 530 to reduce power in an arm distal to its connection point with the applicator. In the arm of the second circulator 520 that interfaces with the applicator 510, a three-stub tuner 532 is disposed distal to the bi-directional coupler 534; this arrangement is intended to minimize microwave reflection and optimize the microwave energy directed to the applicator 510. A quartz window 538 is inserted between the second circulator 520 and the applicator 510 to prevent arcing. When the plasma is off and the microwave is on, a standing wave is set up in the applicator 510 between the three-stub tuner 532 and the sliding shorting plate 540 on the periphery of the applicator 510, and the electric field is sufficient to initiate the decomposition of the feed gas within the reactor tube 514 including the plasma reaction chamber 512. The reactor tube 514 passes through the wide wall of the applicator 510 but does not contact the microwave waveguide 508 directly. Once the start of the plasma state is achieved, the three-stub tuner 532 can then be adjusted to match the impedance of the incoming microwave signal to the plasma load applicator 510.The microwave energy entering applicator 510 is adjusted to peak at the center of plasma reaction chamber 512 using shorting plate 540 as needed to vary the dimensions of the cavity in which the plasma is formed.

[0087] To optimize the power for generating plasma, it is desirable to match the impedance of waveguide 508 to the impedance of applicator 510 in the presence and absence of plasma. However, the plasma impedance is dynamic and can vary based on the operating pressure, gas flow, and gas composition within plasma reaction chamber 512. In an aspect, the microwave subsystem can comprise a standard three-stub autotuner 532 having three metal stubs inserted into the waveguide. The depth at which each of these stubs is inserted into the waveguide changes the phase of the microwaves entering reactor 510, enabling the power to be matched to the plasma. Measurement of the microwave power and phase in autotuner 532 allows autotuner 532 to algorithmically modify the depth of the stubs so that the reflected power (i.e., the power not absorbed by the plasma) is minimized. In an aspect, a bi-directional coupler 534 with a power diode (not labeled) attached can be included to measure the forward and reflected power in the subsystem. The coupler 534 can be adapted with two small holes that couple microwaves with known attenuation to the diode, which converts the microwaves to voltage. In an aspect, the reflected power is less than 1% of the total microwave power sent to the system. In an aspect, microwave applicator 510 is a single-mode resonant cavity that couples microwaves to the flowing gas feed in plasma reaction chamber 512. A sliding electrical short 540 can be constructed within applicator 510 to vary the total cavity length. In an aspect, the plasma for a 100 kW demo unit can generate heat higher than 10 kW, which can be removed by a water and gas cooling subsystem.

[0088] Plasma is generated in a plasma reaction chamber 512 within an elongated reactor tube 514. In an aspect, the reactor tube 514 can include a fused quartz tube having a long aspect ratio, an outer diameter of about 30 to about 120 mm, a length of about 6 ft, and a thickness that varies from about 2.5 to 6.0 mm. In one aspect, the reactor tube can have an outer diameter of 50 mm or 38 mm. In an aspect, the tube size can have an outer diameter (OD) and corresponding inner diameter (ID) of 120 / 114 mm OD / ID or 120 / 108 mm OD / ID or 80 / 75 mm OD / ID or 50 / 46 mm OD / ID or 38 / 35 mm OD / ID. In an aspect, the reactor tube 514 has a constant diameter throughout its length. In other aspects, the reactor tube 514 can have a varying diameter having a particular portion of the tube 514 with a smaller diameter and other regions with a larger diameter. In an aspect, the tube can have an outer diameter of about 50 mm at the top and about 65 mm at the bottom. In an aspect, the tube can have a narrower diameter at a preselected portion of the tube, such as approximately in the middle of the tube. Quartz is advantageous as the reactor tube 514 material because it has high temperature handling, thermal shock resistance, and low microwave absorption.

[0089] FIG. 6 shows in more detail a microwave subsystem 600, such as that shown in FIG. 5, and the paths of microwave energy 605, 607, and 615 flowing therein; in FIG. 6, certain features of the microwave subsystem 600 are schematically shown but not labeled as in FIG. 5 for clarity. As shown in the aspect shown in FIG. 6, the microwave energy generated by magnetron 604 is directed forward along forward energy path 605 from magnetron 604 to the distal end of waveguide assembly 608, from which it is reflected along the forward (forward) reflection path 607. The direction of the forward (forward) reflection path 607 is shaped by its encounter with ferrite array 626 in the second circulator 620, deflecting the reflected microwave 607 towards applicator 610 and plasma reaction chamber 612. The microwave can also be reflected retrograde from applicator 610 along retrograde (reverse) reflection path 615, which passes back through the second circulator 620 to the first circulator 618, where the microwave in this path 615 is collected by water load 622 in the first circulator 618. The retrograde (reverse) reflection path 615 is deflected by ferrite array 626 in the second circulator 620 and then by ferrite array 616 in the first circulator 618 to establish its final direction. In one aspect, the forward power in the system is about 25 kW, with 1% or less of this power being reflected and 0% of the reflected microwave energy being the goal. In aspects, the forward power in the system is about 30 kW; in other aspects, the forward power in the system is about 100 kW. In still other aspects, forward power levels of about 8 kW, about 10 kW, or about 19 - 20 kW can be used. In aspects, the system can advantageously include a forward power at a level of less than about 100 kW.

[0090] In one aspect, the microwave subsystem includes a single arm path to the plasma reaction chamber, as shown in FIGS. 5 and 6. In other aspects, a dual arm applicator path can be used, as shown in FIG. 7 below. As schematically shown in FIG. 7, the dual arm microwave subsystem 700 includes a magnetron 704 that generates microwave energy that enters a circulator assembly 703, which includes two circulators labeled "1" and "2". The microwave energy enters a power divider 706 that substantially passes through the circulator as shown in FIG. 6 and directs the microwaves into two waveguide arms 709a and 709b, where the microwaves are directed to their respective applicators 710a and 710b. In aspects, the dual arm waveguides 709a and 709b and applicators 710a and 710b can split the incident power in a 50:50 ratio, but in other aspects, the power split of a selected ratio can be engineered.

[0091] Certain maintenance criteria within the microwave subsystem can extend the life of components and optimize product output. In an aspect, for example, the reactor can be cleaned periodically. The accumulation of carbon soot can occur within the reactor tube when using non-thermal plasma technology to convert methane to acetylene, and it is understood that the presence of soot can lead to localized regions of overheating on the quartz surface and subsequent damage to the reactor tube. Also, soot accumulating distal to the microwave connection can become conductive and result in the formation of unwanted arcs. Therefore, in an aspect, regular cleaning of the reactor is contemplated to minimize these problems. Cleaning can be contemplated on a regular basis or based on discontinuous requirements for commercial operation or in response to observable characteristics of the plasma or emissions. For cleaning purposes, several steps are typically used: 1) the step of de-energizing the plasma process in the plasma reaction chamber either by turning off the microwave power that generates the plasma or by shifting the gas inflow from the process gas to an inert cleaning gas or gas mixture (e.g., pure N2 or a combination of nitrogen and air or other cleaning gases); or 2) both the steps of interrupting the supply gas inflow and introducing an inert gas mixture (e.g., nitrogen) to purge the inflow line of the combustible supply gas; 3) the step of filling the reactor with a cleaning gas (e.g., nitrogen mixed with air); 4) the step of re-energizing the plasma reaction chamber with microwave energy to form a plasma state from the cleaning gas, monitoring and adjusting the microwave energy and pressure to enable effective cleaning, etc.; 5) the step of reversing the process once the reactor tube is clean by emptying the cleaning gas or replacing the cleaning gas with the supply gas, resulting in the filling of the reactor tube with the supply gas and then energizing the supply gas to form a plasma.

[0092] In one aspect, soot deposition (and thus the need for cleaning) can be minimized by increasing the hydrogen component of the incoming gas; however, this approach has the drawback of reducing the efficiency of hydrocarbon (e.g., methane) conversion. In other aspects, soot deposition can be directly managed by periodic manual cleaning; this approach has the drawback of requiring physical intervention to access the inner surface of the reactor lumen where soot accumulates. In yet other aspects, soot deposition can be managed by periodically changing the gas inflow to the plasma reaction chamber from the hydrocarbon:hydrogen feedstock used to purify acetylene to a hydrogen:nitrogen mixture that forms a plasma that removes soot deposited on the inner surface of the reactor tube with low power. In one aspect, pure CO2 plasma can be used as the cleaning plasma. In one aspect, a hydrogen:nitrogen gas mixture can be used, with an H:N ratio of 5 - 15:1 used at a power of about 8 kW. In one aspect, this gas-based cleaning protocol can be carried out on a periodic basis (e.g., by 1 - 2 minute cleaning runs every 1 or 2 hours), with a downtime of 1 - 2% intended for cleaning from a continuous lance scheme. In other aspects, a nitrogen:air mixture in a ratio of 50:4 can be used, resulting in a cleaning time of about 3 minutes every 2 - 3 hours.

[0093] This aspect of the system includes a parallel microwave reactor setup that shares a vacuum pump and is multiplexed with a heat exchanger and isolation valves for a first reactor and a second reactor connected behind the reactor tube and for each reactor. The magnetron of the first reactor can be shut off, the reactor can be isolated by the isolation valve, and then opened to the alternating vacuum system, while the second reactor is operating to supply energy to the feedstock gas in its plasma reaction chamber. Then a cleaning plasma can be used for the first reactor. Once the cleaning is done, the cleaning gas mixture is discharged from the first reactor system, the reactor system is purged with nitrogen, then purged again with a mixture of fresh feed gas and recycled gas used in the process, and then reopened to the main vacuum system and reignited. Next, the second reactor can be cleaned using the same sequence. In some aspects, the total number of parallel reactors can be increased to include three or more reactors, and their cleaning cycles are sequenced such that the total throughput of the multiplexed system is constant and any one reactor is being cleaned. Thus, this cleaning process can be circulated through the multiplexed reactor system indefinitely, either individually or in small groups, and the cycles are specified at times such that there is no loss of product throughput over continuous use.

[0094] c. Vacuum subsystem In an aspect, the vacuum system is disposed around all components between the gas injector that provides gas inflow to the reactor and the product outflow downstream of the reactor. Maintaining a low pressure within the system contributes to its efficiency (where efficiency is measured in eV of energy per mole of methane converted to acetylene). In an aspect, a vacuum is maintained within the reactor, or a low-pressure environment is created at around about 30 to about 120 Torr or 60 to about 100 Torr or 70 to about 80 Torr. In an aspect, the low-pressure environment is at around about 120 to about 280 Torr or about 150 to about 200 Torr or about 170 Torr. In one aspect, an operating pressure of about 70 Torr is maintained for all hydrocarbon feed gases except ethane processed at an operating pressure of about 120 Torr.

[0095] Figure 8 shows a simplified schematic diagram of a plasma-based hydrocarbon treatment system 800 highlighting vacuum subsystems 802a and 802b, with arrows indicating the direction of gas flow through the system 800. Vacuum subsystems 802a and 802b cover certain components of the treatment system 800 and maintain a pressure in the range of about 30 to about 120 Torr in these components. Alternatively, the same system can maintain a pressure in the range of about 120 to about 280 Torr or about 150 to about 200 Torr or about 170 Torr in these components. As shown in Figure 8, the vacuum subsystem indicated by dashed line 802a creates a first reduced-pressure environment around the reactor 810 and its effluent stream 816 and around various components downstream from the reactor 810, all of which are described in more detail below; the vacuum subsystem indicated by dashed line 802b creates a second reduced-pressure environment around the gas delivery subsystem 804. For clarity, a part of the vacuum subsystem is identified by dashed line 802a and a part of the vacuum subsystem is identified by dashed line 802b; these two dashed lines may represent separate subsystems or they may be combined together to represent a single vacuum subsystem. The subsystems and components shown in this figure are, for clarity: (i) a gas delivery subsystem 804 that passes inlet gases such as hydrocarbon feed gas 806 and hydrogen-containing recycle gas 812 through their respective feed gas inlets (not shown) to the reactor 810; (ii) a microwave delivery system 808a that acts on the inlet gases (i.e., hydrocarbon feed gas 806 and hydrogen-bearing recycle gas 812) within the reactor 810 to form microwaves 808b that affect the chemical conversion in the two inlet gases 806 and 812 within the plasma reaction chamber 811 region of the reactor 810, where the products of these chemical conversions are discharged from the reactor 810 as effluent stream 816; (iii) an effluent separation and disposal system including an acetylene separator 814 and a hydrogen separator 818 that separate the effluent stream 816 into gaseous components, where the remainder of the distal effluent stream 816 of the acetylene separator 814 and the hydrogen separator 818 becomes the recycle gas stream 812.As previously described and as shown in this figure, certain components such as filter 820 for the effluent stream 816, heat exchanger / separator 822, and a series of pumps 824 and 828, which are located downstream from reactor 810 as indicated by dashed line 802a, are also included within the vacuum subsystem. In this figure, cold trap 830 for removing higher hydrocarbons is located outside the vacuum subsystem as indicated by dashed line 802a, similar to acetylene separator 814 and hydrogen separator 818.

[0096] The filter 820 shown in the figure is intended to remove carbon solids from the effluent stream 816. In an aspect, the plasma process produces a small amount of carbon solids as a by-product; for example, the carbon solids can be produced in the range of 0.1 - 0.5%. Therefore, it is desirable to filter the effluent stream 816 to remove these carbon solids to prevent these particles from contaminating downstream components of the system. Since filter 820 is the first surface that the effluent stream 816 encounters after leaving reactor 810, the gas in this stream is very hot (approximately 400 - 1000 °C). Therefore, the material of filter 820 is selected such that it can withstand such temperatures with or without further cooling. In an aspect, filter 820 can be made of a ceramic material or stainless steel, and cooling can be added if necessary.

[0097] d. Cooling Subsystem In an aspect, the cooling subsystem may be implemented to control the operating temperatures of the various components of the gas processing system described herein. In an aspect, the plasma formed within the reactor reaches temperatures of 2000 - 3000 K (1700 - 2700 °C) and is discharged from the reactor at a temperature of about 400 - 1100 °C. Cooling is provided to protect downstream components of the system from thermal damage. Also, it is desirable to cool the reactor itself, for example, to maintain the external temperature of the reactor tube below 500 °C. Further, since the reactor tube is more likely to retain heat during gas-based purging (as described above) and during heat to acetylene production, more cooling power may be required to intermittently protect the reactor tube from thermal stress. In an aspect, the cooling of the system includes two types of cooling: water cooling and gas cooling. Water cooling may be used for many components of the system, such as magnetrons, power sources, vacuum pumps, applicators, etc. Gas cooling may be used for other components, such as the reactor tube, the reactor itself, and various O-ring seals within the system, where appropriate. In an aspect, nitrogen is used for gas cooling. Nitrogen enhances safety as it has the additional advantage of replacing the atmosphere in the enclosed parts of the system. In one aspect, the reactor tube and the applicator may be enclosed within a sealed nitrogen purge (oxygen-free) environment, where the presence of nitrogen provides cooling by replacing oxygen in the environment surrounding the reactor system, serves as a safety mechanism, and the nitrogen gas coolant reduces the chance of explosion in the event of a leak.

[0098] e. Exhaust separation and disposal subsystem In an embodiment, the effluent stream exits the low pressure environment created by the vacuum subsystem and then undergoes further processing to separate the desired gaseous products from each other and from the waste products. Methane and other hydrocarbon-containing gases, such as ethane, propane, butane, etc., produce acetylene and hydrogen along with particulate carbon and higher hydrocarbons when energy is supplied in a non-thermal plasma as described herein. To optimize the economic aspects of the process and provide a regulated gas flow for recirculation, a set of components is placed distal to the vacuum subsystem to separate specific gaseous components in the effluent stream from each other.

[0099] In an embodiment, the plasma-based hydrocarbon treatment system and method of using the same described herein are envisioned to convert methane in a stoichiometry where the net hydrogen is positive, such that 1.5 moles of hydrogen are produced for every 1 mole of methane consumed. Thus, the effluent stream contains a mixture of hydrocarbons including the desired product acetylene along with preponderant hydrogen. In an embodiment, this hydrogen can be separated from the effluent stream using, for example, a membrane separator to separate hydrogen from the remainder of the effluent. After separation, the hydrogen can be purified and commercialized as another gaseous product; alternatively or additionally, the hydrogen can be recycled, in whole or in part, to the system as illustrated in previous figures. In other embodiments, acetylene can be separated from the effluent stream instead of or in addition to hydrogen separation. For example, acetylene can be absorbed in an absorption column and then desorbed and collected. In one embodiment, the effluent stream from the reactor can first be treated to remove particulate carbon and concentrates and then acetylene can be removed. After removing acetylene, hydrogen can optionally be removed, captured, or recycled.

[0100] The effluent stream, upon exiting the plasma reaction chamber, contains a combination of gas, volatilized higher hydrocarbons, and particulate carbon. As previously described, the particulate carbon can be filtered out immediately downstream of the reactor chamber. In an embodiment, the effluent stream can then be passed through a cold trap to remove certain higher hydrocarbons from the effluent stream as a condensate. After passing through the cold trap, the effluent stream can be further separated. For example, other higher hydrocarbons can be removed from the effluent stream as follows. These compounds are typically presumed to be waste products and can be discarded or disposed of after removal. After or simultaneously with the removal of the higher hydrocarbons, acetylene and hydrogen are separated from the effluent stream via an effluent separation and disposal subsystem. The separation process proceeds using one or more separation techniques such as adsorption techniques, absorption techniques, chemical reaction techniques, such as oxidation or catalytic conversion, etc.

[0101] i. Adsorption In one aspect, for example, the effluent stream can pass through an adsorption column, where the column contains a high surface area adsorbent material that can selectively remove acetylene or higher hydrocarbons from the effluent stream flowing therethrough. In an aspect, suitable sized materials such as activated carbon, zeolite, silica aerogel, molecular sieves, metal organic frameworks (MOFs), coordination polymers, clay, diatomaceous earth, or pumice can be mentioned as the adsorbent material. The adsorbent material can be a powder or a film, or can be formed into spherical pellets, rods or other shapes that can be useful. These adsorbent materials can be modified by firing at high temperature, ion exchange or doping with molecules that enhance the adsorption affinity or capacity. Further, combinations of two or more adsorbent materials can be used to utilize multiple physical properties. The adsorbent material can be included in a single adsorbent column or divided into multiple adsorbent columns to trap different impurities from the effluent stream at different locations. Advantageously, the adsorbent material can be selected to minimize product loss as the effluent stream passes through the adsorbent column: in some examples, the higher hydrocarbon impurities have a higher affinity for the adsorbent material than the desired product; in other examples, the impurities can displace the product molecules from the surface of the adsorbent. In either case, product loss is minimal.

[0102] Under certain circumstances, the adsorbent can be disposed of after single use if the capacity of the adsorbent and the concentration of the impurities are sufficient to remove the impurities before disposal. Under other circumstances, for example, if disposal is not feasible for economic or logistic reasons, the adsorbent can be regenerated and recycled cyclically. Methods for regenerating the adsorbent include pressure reduction, solvent washing, heating, and displacement with another gas. During regeneration, the impurities can be desorbed from the surface of the adsorbent, or they can be converted in situ to another chemical substance for which desorption is easier. If the impurities are converted to derivative molecules that can be tolerated, this molecule can be desorbed in-line and released into the process stream. If the impurities do not change on the surface of the adsorbent, they cannot be released into the downstream flow, so they can be diverted to a side stream and discharged, incinerated, or collected for waste disposal. In an aspect, an automated system can be arranged for alternation between or among a plurality of adsorbent vessels, enabling a regeneration cycle in continuous operation; such a system is referred to in the art as a swing adsorbent.

[0103] The adsorber can be used for further separation of the effluent stream after removal of higher hydrocarbons. Depending on the preferred form of adsorption and desorption, a pressure swing adsorber (PSA), a vacuum swing adsorber (VSA), or a temperature swing adsorber (TSA) can be used. For example, in one aspect, the effluent stream can be fed to a PSA system to separate hydrogen gas from the effluent stream. In a PSA system, the effluent stream is pressurized and fed to an adsorption column, in which all non-hydrogen components are adsorbed onto the adsorbent material. When all non-hydrogen materials have been removed from the stream, the purified hydrogen is discharged from the column. In an aspect, the feed for the PSA system can be the effluent stream from a plasma reactor, or it can be the gas collected from the first absorption column described above or some combination thereof.

[0104] Alternatively, for example, the effluent stream can be fed to a TSA system adapted to separate higher acetylenes from the effluent stream. As used herein, the term "higher acetylenes" refers to at least alkynes containing 3 and 4 carbon atoms, although this can also apply to all gaseous alkynes and gaseous aromatics. By use of the TSA system, higher acetylenes can be separated from the acetylene stream significantly and even completely without acetylene loss. In an embodiment, the higher acetylene molecules can displace the acetylene on the surface of the adsorbent, allowing for the highest selectivity in the separation of higher acetylenes from the acetylene stream. To achieve this, the adsorption process is advantageously terminated before the higher acetylenes themselves are displaced by even heavier molecules such as benzene. Thus, the adsorption cycle in TSA should be adjusted such that the higher acetylenes are adsorbed and retained on the adsorbent surface, but the higher acetylenes are prevented from being displaced. Accordingly, the reactor is closed to the process stream before the higher acetylenes are displaced from the adsorbent surface. The adsorbent can then be disposed of and replaced, or alternatively regenerated. In regeneration, the effluent stream is diverted from the adsorber and hot air (e.g., >300 °C or >350 °C) is passed through the adsorbent bed. Alternatively, regeneration can be carried out using hot nitrogen or some mixture of air and nitrogen. In an embodiment, the gas temperature can be from 120 °C to 350 °C. The regeneration gas mixture and temperature can vary over the course of regeneration. Regeneration can also be carried out while actively cooling the adsorbent bed, either in certain sections or in its entirety. The location and amount of any cooling can also vary over the course of regeneration. The impurities are released from the adsorbent and either discharged or combusted. In some iterations, multiple vessels can be used in continuous operation, with some vessels adsorbing and others being regenerated.

[0105] The adsorber vessel can be covered with an insulating material to maintain a high temperature during either operation and / or regeneration. The adsorber design can include many aspects known to those skilled in the art. Internal devices such as spreaders, distributors, tubes, channels, plates, screens, etc. can be used to control the process and regeneration gas flow. Additional internal devices such as screens, supports and other packing materials can be used to control the position and / or performance of the adsorbent. Further, internal objects for improving heat transfer can be used, such as materials having a higher thermal conductivity in various physical shapes such as rods, tubes, wires, spheres, etc. In an aspect, the amount of filter material can be approximately 0 to 50% of the adsorber volume. Further, the adsorber can include a design and / or system for actively cooling the bed, such as a tube and shell design.

[0106] In another aspect, the TSA can be modified to remove carbon dioxide and hydrogen sulfide in addition to higher acetylenes. By operating the TSA under pressure, the adsorbent can simultaneously remove carbon dioxide, hydrogen sulfide, higher acetylenes and aromatic mixtures (such as a mixture of benzene, toluene and xylene isomers, collectively referred to as BTX). This can be achieved by operating the TSA at a pressure higher than 5 barg. Other arrangements that enable the selective removal of impurities can be readily conceived by those skilled in the art. For example, specific impurities such as CO2 and / or BTX can be removed by a dedicated removal system before directing the gas stream to the TSA, and the operating parameters of the TSA are adjusted to remove the remaining impurities. Impurities in the gas stream such as alcohols (methanol, ethanol, butanol, etc.), sulfides and mercaptans, acetone and other small ketones, water, ammonia, carbon monoxide and carbon dioxide, oxygen, etc. can be removed by adjusting the TSA parameters and / or applying pressure by a temperature swing adsorption process.

[0107] In one aspect, the adsorption process can be modified such that acetylene and hydrogen can be separated through a temperature swing adsorption mechanism by modifying the timing of the temperature swing adsorption process or by modifying the amount of adsorbent in the TSA. In an aspect, the adsorption period for separating hydrogen and acetylene is shorter compared to the adsorption period for an adsorber fabricated in a constant size for separating acetylene from higher acetylenes, and can be referred to as "short cycle temperature swing adsorption". By exposing the gas stream to temperature swing adsorption during this shortened amount of the total TSA cycle, the short cycle temperature swing adsorption process separates hydrogen from a mixture of acetylene and higher acetylenes. Thus, short cycle temperature swing adsorption is particularly advantageous when the product mixture of acetylene and higher acetylenes is desired. The cycle for short cycle temperature swing adsorption can be understood in more detail as follows: If the length of the total temperature swing adsorption cycle (from the start of adsorption to the start of adsorber regeneration) is T x then the limited time at the start of the adsorption cycle T1 can be spent separating acetylene and the higher acetylenes entrained therewith from the hydrogen stream, and the TSA remains offline for the remainder of the adsorption cycle T2, where T2 = T x - T1. This regulated adsorption schedule for short cycle temperature swing adsorption uses the first portion of the total adsorption cycle T1 for separating acetylene and the higher acetylenes entrained therewith from hydrogen, where T1 ranges in length from 10% to 25% of the total cycle T x . To use short cycle temperature swing adsorption, a TSA system as described above is operated during the first portion of its cycle T1 to separate acetylene and higher acetylenes from the gas stream and allow hydrogen to pass through. The TSA system then remains offline for the remainder T2 of its cycle. Regenerating the TSA adsorbent at the end of T2 prepares the TSA for another separation cycle.

[0108] TSA can be used during either short or regular cycles of temperature swing adsorption after its regeneration at the end of T2, but an alternation of short and regular cycle temperature swing adsorption using the same TSA device cannot be advantageous. Instead, a single TSA device can be dedicated to the short cycle process; in such a dedicated device, regenerating the TSA adsorbent at the end of T2 prepares the device for another cycle of separating acetylene and higher acetylenes from hydrogen, namely short cycle temperature swing adsorption. The short cycle temperature swing adsorption process removes acetylene and mixed higher acetylenes from the gas stream, while hydrogen passes through the TSA, and then the hydrogen and acetylene mixture can be processed separately after passing through their TSA devices. As an alternative to varying the duration of the adsorption cycle as described above, equivalent separation can be achieved by increasing the amount of adsorbent in the TSA device without changing the time frame for exposure to the gas stream, or in conjunction with changing the time frame for exposure to the gas stream.

[0109] As described above, short cycle temperature swing adsorption separates acetylene from the incoming gas stream, along with higher acetylenes associated with the acetylene. Thus, the product produced by short cycle temperature swing adsorption is acetylene combined with higher acetylenes. In contrast, standard TSA separates higher acetylenes from the gas stream, leaving a mixture of hydrogen and acetylene, which needs to be further separated into a hydrogen fraction and a purified acetylene fraction. In contrast to the short cycle temperature swing adsorption process, standard cycle TSA is offline during the first part (T1) of the cycle having a time duration T x and operates during the later part T2 of the cycle; regular cycle TSA is online during a period that approximately corresponds to the time when short cycle TSA is offline. Similar to short cycle TSA, standard cycle temperature swing adsorbers initiate adsorbent regeneration at the end of the cycle time T x , but in contrast to short cycle TSA, standard cycle TSA remains offline during the first quarter of the cycle (T1).

[0110] For certain uses, the separation of acetylene and higher acetylenes from residual hydrogen results in commercially acceptable product yields, as carried out by a short cycle TSA process. For example, in the torch applications described in more detail below, it may be acceptable to include higher acetylenes in the acetylene product yield, and a simple separation of an acetylene / higher acetylene mixture from residual hydrogen is commercially acceptable. In such applications, the short cycle TSA can be used as a single stage to separate the acetylene and higher acetylene product yields from the residual hydrogen stream. For other uses, a substantially pure acetylene product is desired, where the higher acetylenes have been removed from the acetylene product yield. For these purposes, the use of short cycle temperature swing adsorption can be combined with standard cycle temperature swing adsorption in a multi-step process. For example, standard cycle temperature swing adsorption can remove the higher acetylenes from the gas stream as it passes through the first TSA, and then the effluent from the first TSA (such effluent is still a mixture of hydrogen and acetylene but the higher acetylenes have been removed) can be directed to a second TSA that uses short cycle temperature swing adsorption to separate the purified acetylene from the gas stream, allowing the hydrogen to pass through. Other separation mechanisms (absorption, membranes, etc.) can be used in combination with short cycle TSA to remove the higher acetylenes from the short cycle adsorption product, but the use of short cycle TSA combined with standard cycle TSA can provide an advantageous alternative to using a standard cycle TSA combined with membrane-based separation techniques that require pressurizing the gas flow, passing it through a membrane, and performing acetylene / hydrogen separation. In other aspects, a TSA such as standard TSA or short cycle TSA can be carried out while maintaining the following parameters. In a TSA system having a given adsorbent, volume, temperature, pressure, flow rate, inlet composition, and other characteristics that are constant or a function of a given time, the time for capturing a particular gas A by the TSA is T c (A), or what can be referred to as the "capture period". That is, T c(A) (Capture period for gas A) is the time between the instant the bed goes online and the instant just before the gas species A reaches an unacceptable concentration in the effluent gas stream. In a short-cycle TSA designed to capture acetylene, for example, the capture period for acetylene is T c (acetylene) or T c (C2H2). For standard TSA, the first species to be captured is the higher acetylene species, gas B, which first appears in the effluent gas stream; its capture period is T c (B). For standard TSA, the bed must be taken offline and regenerated or replaced after T c (B). Similarly, for a short-cycle TSA designed to separate acetylene from the rest of the gas stream, this must be taken offline and regenerated or replaced after T c (C2H2).

[0111] When it is advantageous to have a series of standard TSA before the short-cycle TSA, for each device, it may also be advantageous to design the adsorbent bed such that T c (B) for the standard TSA is equal to T c (C2H2) for the short-cycle TSA in terms of duration. When the adsorbent beds are designed on these aligned scales, the short-cycle TSA can be exposed to a certain amount of acetylene in each cycle.

[0112] In an embodiment, the cycle timing for a series of standard TSA can be arranged as follows before the short-cycle TSA. For standard TSA, acetylene is captured through T c (C2H2). Then, during T c which is after the end of T c (C2H2) but before the end of T r , acetylene is desorbed from the standard TSA when it is replaced by the higher acetylene that continues to be adsorbed. Therefore T cBetween (C2H2), the gas discharged from the standard TSA does not have both acetylene and higher acetylenes. T r Between, the gas passing through the standard TSA is enriched in acetylene but still does not have higher acetylenes. Since the acetylene replaced by the higher acetylenes on the standard TSA adsorbent bed is added to the outflow stream, this time T r Between, the amount of acetylene in the outflow stream from the standard TSA is greater than the amount entering the standard TSA. T c The total amount of acetylene flowing through the standard TSA adsorption bed over (B) flows out through the standard TSA outflow stream over a shorter duration T r Therefore, since acetylene is adsorbed on the standard TSA, the short cycle TSA does not adsorb acetylene during T of the standard TSA c (C2H2). T r Between, the acetylene discharged from the standard TSA reaches and is adsorbed by the short cycle TSA. If the short cycle TSA is appropriately sized to have an acetylene saturation time that meets or exceeds the higher acetylene capture period T of the standard TSA c (B), the gas exiting the short cycle TSA does not have both acetylene and higher acetylenes during its active period, i.e., over the entire T of the standard TSA c (B). At the end of this active period, both vessels can be taken offline, replaced with new vessels, and / or regenerated.

[0113] In one aspect, the stream being processed in a standard or short - cycle TSA can contain various products that have a weak affinity for the adsorbent media and thus readily pass into the effluent gas along with hydrogen. Such weakly - affinitive gases that can be present in the hydrogen - rich effluent gas include methane, nitrogen, carbon dioxide, and low - mass alkane and alkene species. In such cases, standard TSA separates higher acetylenes from the effluent gas mixture of gases that have a weak affinity for both acetylene and the adsorbent, and short - cycle TSA separates acetylene and higher acetylenes from gases with a weak affinity. As a general principle set, standard TSA can be used when the desired effluent gas contains a mixture of gases that have a weak affinity for both acetylene and the adsorbent, while short - cycle TSA can be used when the desired effluent gas contains only gases that have a weak affinity for the adsorbent. To separate acetylene from higher acetylenes and from gases that have a weak affinity for the adsorbent, standard TSA can be used in combination with short - cycle TSA, for example, in two successive steps of standard TSA followed by short - cycle TSA.

[0114] For the production of hydrogen and acetylene black, torch gas production, or other applications that may tolerate or require an impurity stream, various adsorption strategies can be implemented to separate acetylene with an ideal mixture of impurities. These strategies can include the splitting and recombination of gas streams desorbed from or passing through one or more separation modules.

[0115] For example, the splitting can be done based on gas flow, adsorbent temperature or pressure, or time - on - stream. The composition of the gas captured by the adsorbent is variable based on temperature, pressure, the period the bed is on - stream, the type of adsorbent, and other factors. Therefore, during regeneration, the composition of the gas stream released from the adsorbent bed changes as it is heated or depressurized over time. The composition of the released gas can be further controlled by separating the gas based on the temperature and pressure of the adsorbent when the gas is released.

[0116] To achieve gas separation using this technique, the regenerated TSA bed is heated over time. The adsorbent bed initially releases a hydrogen-rich gas mixture near the starting temperature. Then, nearly pure acetylene is desorbed at a moderate temperature. As the temperature further increases, a mixture of acetylene and higher acetylenes is released from the adsorbent. Finally, the heavier compounds remain and must be liberated with the aid of hot air as the regeneration gas. This TSA bed has a first portion of the released gas (i.e., the hydrogen-rich gas mixture) that is directed back towards the active TSA bed for further processing. The pure acetylene, which is the second portion of the released gas, can be used as a feedstock for chemical processing and the like as described in more detail below. The third portion, which contains acetylene and higher acetylenes, can be directed to a reactor for conversion to hydrogen and acetylene black as described in more detail below. The fourth portion, which contains the heavier compounds, is removed with the air, exhausted, and can restore the adsorbent to its initial state.

[0117] ii. Absorption In certain embodiments, the effluent stream may pass through an absorption column where a solvent flowing countercurrent to the effluent stream at an optimal flow rate preferentially absorbs higher hydrocarbons from the flowing effluent stream instead of absorbing the desired gaseous product such as acetylene. The higher hydrocarbons can then be separated from the solvent in a second column and the solvent is returned to the absorption column. Examples of solvents having a stronger affinity for higher hydrocarbons than for the desired gaseous product include methanol, ammonia, toluene, benzene, kerosene, butyrolactone, acetonitrile, propionitrile, methoxypropionitrile, acetone, furfural, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-formylmorpholine, and N-alkylpyrrolidones such as N-methylpyrrolidone (NMP).

[0118] In other embodiments, the effluent stream may pass through an absorption column, where a solvent having a strong affinity for acetylene, preferably flowing countercurrent to the effluent stream, absorbs acetylene from the flowing effluent stream. The absorbed acetylene can be removed from the solvent by heating the solvent in a second column to recover the solvent, and then the recovered solvent can be returned to the absorption column. Examples of solvents having a stronger affinity for acetylene than other effluent gases include methanol, ammonia, toluene, benzene, kerosene, butyrolactone, acetonitrile, propionitrile, methoxypropionitrile, acetone, furfural, N,N-dimethylformamide, N,N-diethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide, N-formylmorpholine, and N-alkylpyrrolidones such as N-methylpyrrolidone (NMP).

[0119] iii. Chemical Reactions In certain embodiments, higher hydrocarbons in the effluent stream can be oxidized and thereby removed from the effluent stream. For example, certain higher hydrocarbons, particularly diacetylene and substituted acetylenes such as methylacetylene and vinylacetylene, can be difficult to separate from acetylene and can be removed by conversion to non-acetylene compounds. To achieve this, the effluent stream can be passed through a column or vessel containing an oxidizing agent such as a concentrated liquid acid that can act as an oxidizing agent, such as nitric acid, sulfuric acid, phosphoric acid, etc. Higher hydrocarbons such as diacetylene and substituted acetylenes can react with the oxidizing agent or concentrated acid to produce other hydrocarbon compounds that can be more easily separated from the effluent stream. In certain embodiments, the effluent stream can be contacted with phosphoric acid on a solid support to convert higher hydrocarbons such as diacetylene and substituted acetylenes to other hydrocarbon products that can be more easily separated from the effluent stream.

[0120] In certain embodiments, the effluent stream can be passed through a catalyst bed using a catalyst comprising a transition metal, a transition metal oxide, a transition metal salt, or a zeolite to convert various higher hydrocarbons into other carbon species that can be more readily removed from the gaseous product stream. When exposed to a suitable catalyst, these higher hydrocarbons can be converted into more readily removable compounds by catalyst-derived mechanisms such as polymerization, oxidation, hydrogenation, and disproportionation. Depending on the mechanistic mode of the catalytic conversion and the products obtained, these derivatives of the higher hydrocarbons can be removed by further downstream processes such as those described herein.

[0121] iv. Other separation techniques In certain embodiments, higher hydrocarbons can be removed from the effluent stream using a condenser, which collects these compounds on a high surface area material such as silica gel, activated carbon, activated alumina, zeolite, etc. For example, certain higher hydrocarbons, such as methylacetylene and vinylacetylene, can be difficult to separate from acetylene in gaseous form, but their freezing points (5.01 °C and 10.3 °C, respectively) are in contrast to that of acetylene (-84 °C), making them suitable for removal from the effluent stream by freezing. In this embodiment, a cold bed containing a high surface area material at a temperature between -84 °C and 10 °C can effectively freeze out and remove the higher hydrocarbons from the effluent stream.

[0122] In one aspect, the effluent stream can pass through the gas separation membrane system, where gas molecules are separated by size exclusion. For example, smaller molecules such as hydrogen preferentially flow through the membrane element to form a permeate stream, while larger molecules such as methane, acetylene, higher hydrocarbons, nitrogen, carbon dioxide, and any other large molecules do not flow through the membrane (depending on the porosity of the membrane) and form a retentate stream. In one aspect, the permeate stream is a hydrogen-enriched stream and the retentate stream is a hydrogen-depleted stream. The gas separation membrane element can be formed of various materials such as: a hollow fiber polymer membrane where the polymer can be polycarbonate, polyamide, or cellulose acetate; an inorganic membrane where the inorganic material can be mesoporous silica, zeolite, metal-organic framework, or a mixed metal oxide; a metal membrane where the metal can be palladium or a palladium-silver alloy, etc. In an aspect, the feed for the membrane separation system can be the effluent stream from the plasma reactor, or it can be the collected gas from the first absorption column described above or some combination thereof.

[0123] Following these specific effluent separation membranes, in one aspect, the effluent stream containing acetylene, hydrogen, and higher hydrocarbons can be further separated into its components so that the desired gas product can be recovered. In other aspects, the effluent stream is not subjected to further separation if, for example, it is used for further chemical processing or is provided to a consumer or end user as a mixed stream.

[0124] f. Data Management and Security Subsystem Advantageously, the all-gas generation system includes interconnected data management and safety subsystems, so the safety criteria incorporated into these systems and methods are informed by data collected about the performance of the system. In an aspect, data management can include devices, procedures, and algorithms for data collection and performance diagnostics, as well as storage facilities for recording and storing data. In an aspect, performance diagnostics includes monitoring the state of the system within normal parameters to facilitate overall integration and control, as well as identifying signs of impending or ongoing failure states. Optical diagnostics can be directed with visible light cameras, mid-IR pyrometers, wide area spectrometers, etc., for surveillance of the plasma region. Device diagnostics can include pressure transducers, thermocouples, flow meters, microwave power sensors, etc. Other diagnostic devices, such as full scale spectrometers and oscilloscopes, can be used when appropriate. In an aspect, the various diagnostic aspects can be integrated and monitored automatically and / or manually during a run.

[0125] In an aspect, the manual and automatic diagnostic procedures can be integrated with safety procedures that can include a fault-interlock system. In one aspect, the diagnostic inputs can be actively monitored by hardware and software. If an anomaly is detected, a failure signal can be induced that activates a predetermined response pattern. For the most severe failures, such as a sudden reinforced pressure spike, an immediate automated "hard" shutoff can be induced. For medium severity failures where the consequences are not as severe, a slower automated shutoff that is intended to stop operation can be induced over a period of seconds. For these failures where the parameters are outside the expected range but no major consequences are expected, the operator can be warned so that appropriate actions are taken to correct the situation and clarify the failure without the need to shut down the system.

[0126] 3. Exemplary Systems and Subsystems a. 100kW Power Plasma-Based Hydrocarbon Processing System A plasma-based hydrocarbon treatment system using plasma technology to convert hydrocarbon-containing feed gas into acetylene and hydrogen can achieve advanced feedstock hydrocarbon conversion, combined with high selectivity for the production of acetylene and / or hydrogen. The system described below uses a 100 kW power source to generate microwaves that form plasma and perform chemical conversion.

[0127] The central reaction of this process occurs when methane (e.g., from natural gas or biogas) or another C2-C4 feedstock hydrocarbon is supplied to a microwave energy supply region where it is decomposed into plasma. Without being bound by theory, the plasma is hypothesized to drive the reaction of the feedstock hydrocarbon to acetylene and hydrogen by decomposing the hydrocarbon into excited CH x radicals that recombine again after the plasma energy state to form a spectrum of hydrocarbon products and hydrogen. By using C2-C4 hydrocarbons as the feedstock, the overall process efficiency can be improved compared to methane, while high selectivity for acetylene can be maintained. However, using methane such as that contained in natural gas or biogas has the advantages of high operating efficiency and cost-effectiveness.

[0128] The methane conversion process in a 100 kW power processing system (i.e., using methane as found in natural gas or biogas feeds or pure methane feeds) uses approximately 9.5 kWh per kg of the acetylene product formed, and the acetylene yield is 90%: about 90% of the feed gas used is converted to acetylene. The resulting product mixture is affected by the non-thermal nature of the plasma temperature. The gas temperature is between 3000 and 4000 K, and the vibrational and electron temperatures are 2 to 3 times higher, pushing the reaction equilibrium to form acetylene with high selectivity and with abundant hydrogen as a by-product. The hydrogen produced by the plasma reaction can be recycled back into the system as a second feed gas for use in subsequent reactions, and / or it can be separated as another gaseous product. The co-presence of hydrogen and hydrocarbons as components of the reaction reduces the formation of solids in the reaction. To achieve the desired ratio of hydrogen and methane for the reaction, as described in more detail below, the system recycles the hydrogen produced to participate in the methane-based reaction.

[0129] i. Overall system The 100 kW power-supplied plasma-based hydrocarbon treatment system includes four subsystems: gas delivery, microwave, vacuum, and cooling. The gas delivery subsystem includes two inlet lines. The first inlet line is a supply line that conveys a mixture such as natural gas continuously supplied from a local utility company or an upgraded biogas containing a mixture of mainly methane and small amounts of ethane, propane, carbon dioxide, and nitrogen (depending on the source of the raw gas mixture). This inlet is cleaned using conventional techniques before it enters the plasma reaction chamber, resulting in a nearly pure methane stream, with other residual gas mixture components present at around 100 ppm. The total flow from this inlet line can be scaled up using the overall microwave power of the system and has a flow of approximately 3 SLM methane / kW microwave power. The second inlet line conveys a recycle gas generated by the reactor, containing approximately 85% to approximately 90% hydrogen, with small amounts of methane and nitrogen, and having an unreacted nitrogen content, for example, in an amount of approximately 5% to approximately 6%. The total flow from this inlet line is also scaled up using the overall microwave power of the system and has a flow of approximately 5 SLM recycle gas / kW microwave power.

[0130] Each inlet stream is sent through its own inlet into the plasma reaction chamber, which injects its flow into the entry region of a quartz tube and flows through the tube to the region where plasma is generated. The inlets of each inlet stream are angled by a gas injector device to create a swirling flow that mixes the flows within the quartz tube so that they flow into the reaction region, i.e., the plasma reaction chamber. The flow of gas entering through each inlet is controlled by a mass flow controller adjusted to produce a hydrogen-to-methane molar ratio of 1.5 H2:1 CH4. When methane is converted to plasma, the spectrum of the reaction products is formed within the plasma reaction chamber in the quartz tube.

[0131] When methane is used as the feed gas, approximately 95% of the methane undergoes chemical changes within the plasma. Acetylene accounts for 95% of the hydrocarbons produced from the plasma energy supply reaction, resulting in an overall acetylene yield of approximately 90%. Hydrogen is another dominant reaction product from these reactions and accounts for approximately 80 volume % of the total effluent stream.

[0132] An exemplary 100 kW power supply plasma-based hydrocarbon treatment system 900 is schematically shown by the block diagram presented in FIG. 9. As shown in this figure, a central reactor 902, which includes an injection region 904, a reaction region 908, and an effluent region 910, receives two separate gas flows: (1) a feed gas 912 that includes source hydrocarbons (e.g., methane in a mixed gas such as natural gas or biogas, or a single C1-C4 hydrocarbon or a mixture of conditioned C1-C4 hydrocarbons) and (2) a recycle gas flow 914 that includes hydrogen and a mixed hydrocarbon-containing gas and optionally unreacted nitrogen.

[0133] As schematically shown in the figure, the incoming gas streams 912 and 914 are processed in reactor 902 to form an effluent stream 918 that contains acetylene, hydrogen, and a small proportion of mixed hydrocarbons. The effluent stream 918 is then separated into its gaseous components via a gas separation system 928 (e.g., adsorption, absorption, or a combination thereof), yielding an acetylene stream 920 and a hydrogen-dominated gas stream 922 that contains hydrogen 936 and a mixture of hydrocarbons 924. Thus, diverted from the main effluent stream 918 by the gas separation system 928, the acetylene stream 920 can be purified by further isolation of impurities within the purification system 926 to yield a purified acetylene gas product 932. Once the acetylene component 920 is removed from the effluent stream 918, the remaining gas stream 922 is predominantly hydrogen, along with a mixture of hydrocarbon reaction products, i.e., hydrogen-dominated. This hydrogen-dominated gas stream 922 can be subjected to further separation if desired, so that hydrogen gas is isolated as a separate gas stream 930. The hydrogen gas product stream 930 can be further purified if necessary, sold as a product, or it can be recycled back to the reactor 902 for further reaction with the feed gas 912. In this system 900, instead of recycling the hydrogen gas product stream 930, the mixed hydrogen-dominated gas stream 922 is recycled to form a recycle gas flow 914, which is reintroduced into the reactor 902 for further reaction with the feed gas 912. Mass flow controllers 940 and 942 coordinate the inflow of the feed gas 912 and the recycle gas 914 into the reactor 902 to yield a desired ratio of hydrogen to methane (or hydrogen to other feedstock hydrocarbons) within the reactor 902.

[0134] ii. Reactor The reactor identified in FIG. 9 is shown in more detail in FIG. 10. FIG. 10 schematically shows the reactor 1002, its components, and its integration with the microwave subsystem 1004. As shown and outlined by the gray shaded box, the microwave subsystem includes a power source and magnetron complex 1016 for generating microwaves and a waveguide assembly 1020 for directing the microwaves to a reaction region 1012 within a quartz tube where a microwave plasma 1018 is formed. As shown in FIG. 10, the quartz tube 1008 includes the components of the reactor: an injection region 1010, a reaction region or reaction chamber 1012, and an outflow region 1014. Within the quartz tube 1008, the microwave plasma 1018 is generated by microwaves (not shown) directed into the gas flow 1006 within the tube 1008, thereby effecting the conversion of feedstock hydrocarbons to hydrogen and various hydrocarbon-derived products. This quartz tube 1008 is inserted through the wide wall of the microwave waveguide assembly 1020. The size of the quartz tube 1008 depends on the amount of microwave power used in the system. For the system shown using 100 kW of power to generate microwaves, the quartz tube 1008 has an outer diameter of 80 mm, an inner diameter of 75 mm, and a length of 1700 mm and is maintained at a pressure of about 70 torr by a downstream vacuum pump (not shown). The relationship between the quartz tube 1008 and the microwave subsystem 1004 is described in more detail below.

[0135] As shown in FIG. 10, the recirculation gas stream 1022 is mixed with the feed gas stream 1024 within the injection region 1010 of the reactor 1002, and each stream enters the injection region 1010 of the reactor 1002 through its own inlet (not shown). The passage of each gas stream to the reactor 1002 through the gas injector device 1032 (also schematically shown in FIG. 11) affects its direction, flow rate, and velocity. As shown in FIG. 10, any gas stream(s) 1028 can be directed into the injection region 1010 and mixed with the recirculation gas stream 1022 and the feed gas stream 1024 to produce a swirling gas flow 1006. After mixing, the gas in the gas flow 1006 flows distally through the quartz tube 1008, encounters the microwave energy generated by the power source and magnetron complex 1016, and is delivered through the waveguide assembly 1020 to the reaction region 1012 of the reactor 1002. The interaction of the microwave energy and the gas within the reaction region 1012 of the reactor 1002 produces a plasma 1018. The effluent gas stream 1034 containing the reaction products exits the plasma 1018, enters the effluent region 1038 of the quartz tube 1008, and is discharged from the reactor 1002 for further separation 1040. As shown in this figure, the microwave subsystem 1004 includes the power source and magnetron complex 1016 as well as the waveguide assembly 1020; further elements of the microwave subsystem shown and described in the following figures are not shown in this figure.

[0136] Figure 11A is a schematic cross-sectional view (not to the same scale) of an embodiment of a gas injector suitable for use with a 100 kW power supply plasma-based hydrocarbon treatment system, such as the gas injector 1032 shown in FIG. 10. For illustrative purposes, the cross-sectional view of FIG. 11A corresponds to the cross-section taken along line A-A' of FIG. 10. FIG. 11A shows a gas injector 1106 disposed within the reaction chamber 1102 of the plasma reactor 1100, providing a plurality of gas flows within the reaction chamber 1102 for these gases as described above to encounter microwave energy. As shown in this figure, the gas injector 1106 provides flow paths for two separate gas flows to the reactor 1102, each gas flow being directed to the reactor 1102 through its own nozzle and flow path within the gas injector device 1106. As shown in FIG. 11A, there are four injector ports, two for the recirculation gas flows 1104a and 1104b and two for the feed gas flows 1108a and 1108b. In this figure, the two recirculation gas nozzles 1104a and 1104b are in fluid communication with a first central flow channel 1110, through which the recirculation gas flow enters the gas injector 1106 and is directed to the recirculation gas nozzles 1104a and 1104b. Similarly, there is a second centrally located channel 1112 within the gas injector 1106 for the feed gas, where this channel is separate from the first central flow channel 1110 for the recirculation gas flow. There are two nozzles for the feed gases 1108a and 1108b that are in fluid communication with the second centrally located channel 1112, and these nozzles 108a and 1108b enter the reactor 1102 at a different level from the nozzles for the recirculation gases 1104a and 1104b. The nozzles for both types of gas flows are directed in a direction conductive to the formation of a swirling gas flow within the reactor 1102. The channels for the recirculation gas 1110 and the channels for the feed gas 1112 do not cross each other, but rather provide separate gas flows to their respective nozzles 1104a / 1104b and 1108a / 1108b; neither nozzle crosses the other, but rather provides their gas flows separately to the reactor 1102.The gas flow through each nozzle can be coordinated with other gas flows in other nozzles with respect to flow rate, path length, and pressure drop.

[0137] Assuming that the channels for each gas are maintained separately from each other in the gas injector 1106, and further assuming that each separate gas flow enters the reactor 1102 through its own separate nozzle(s), those skilled in the art will understand that the relative positions of the supply gas channel 1112 and the recirculation gas channel 1110 can be rearranged, for example, as parallel channels at different heights within the gas injector 1106, as helical, or as some other arrangement different from that shown in FIG. 11A. Further, assuming that the gas flow for each component gas (i.e., supply gas and recirculation gas and any further gas) enters the reactor through its own nozzle without mixing with other gas flows, the number, configuration, and orientation of the nozzles can vary.

[0138] Figure 11B is a schematic cross-sectional view (not to the same scale) of another embodiment of a gas injector suitable for use with a 100 kW power plasma-based hydrocarbon treatment system, such as the gas injector 1032 shown in FIG. 10. For illustrative purposes, the cross-sectional view of FIG. 11B corresponds to the cross-section taken along line A-A' of FIG. 10. FIG. 11B shows a gas injector 1156 disposed in the reaction chamber 1152 of the plasma reactor 1150 that provides a plurality of gas flows into the reaction chamber 1152 for these gases to encounter microwave energy, as described above. As shown in this figure, the gas injector 1156 provides flow paths for two separate gas flows into the reactor 1152, and each gas flow is directed into the reactor 1152 through its own set of nozzles within the gas injector device 1156. As shown in FIG. 11B, there are eight injector ports or nozzles, four for the first gas flow, e.g., the recirculation gas flow (1154a, 1154b, 1154c, and 1154d), and four for the second gas flow, e.g., the feed gas flow (1158a, 1158b, 1158c, and 1158d). In the figure, the four nozzles (1154a, 1154b, 1154c, and 1154d) for the first gas flow are in fluid communication with the central flow channel 1162 through which the first gas flow enters the gas injector 1156 and is directed to the appropriate nozzles 1154a, 1154b, 1154c, and 1154d. The nozzles 1158a, 1158b, 1158c, and 1158d for the second gas flow are each supplied by a respective one of the separate flow channels 1160a, 1160b, 1160c, and 1160d. Assuming that the flow channels for the second gas flow do not mix the second gas flow with the first gas flow, other arrangements of the flow channels for supplying the nozzles 1158a, 1158b, 1158c, and 1158d for the second gas flow can be envisioned. Instead, each gas flow is conveyed by its own separate set of nozzles and its own flow channel(s).The nozzles 1154a, 1154b, 1154c, and 1154d for the first gas flow and the nozzles 1158a, 1158b, 1158c, and 1158d for the second gas flow are oriented in a direction that is conductive for the formation of a swirling gas flow within the reactor 1152. The gas flow through each of the nozzles can be coordinated with the other gas flows in the other nozzles with respect to flow velocity, path length, and pressure drop.

[0139] iii. Microwave Subsystem The microwave subsystem shown in FIG. 10 is schematically shown in more detail in FIG. 12. Referring to FIG. 10, the reaction region 1012 of the reactor 1002 can be seen to intersect the waveguide assembly 1020, where the microwaves are directed towards the gas flow 1006 when it enters the reaction region 1012 to form the plasma 1018. The microwave subsystem 1004 is the cause of generating the microwaves and directing them towards the reactor 1002.

[0140] The microwave subsystem is shown in more detail in FIG. 12. As shown in this figure, the microwave subsystem 1200 includes a power source 1208, a magnetron 1210, a waveguide assembly 1202 (including a waveguide 1212 and certain other standard microwave components described below), and an applicator 1204. The power source 1208 converts 480V, 150A AC power to 20kV - 21kV, 5.8A low - ripple DC power with a 96% conversion and supplies energy to the magnetron 1210. The magnetron 1210, evaluated at 100kW, produces continuous microwave power with an efficiency of 83 - 89%. The generated microwaves are in the L - band frequency range, approximately 915MHz. The microwaves are launched into the waveguide assembly 1202, where the waveguide 1212 directs them through other components of the system to the applicator 1204, where they interact with the gas / plasma in the plasma reaction chamber 1214. The waveguide 1212 features a 90° bend 1216. One of the components of the waveguide is an isolator 1218 to which a water load 1220 is attached and which is located distal to the magnetron 1210. By using a ferrite core 1222 to direct the microwaves to the water load 1220, the magnetron 1210 is protected from the reflected (non - absorbed) microwaves. Other components of the waveguide assembly 1202 adjust the microwaves to induce them into the plasma reaction chamber 1214 and optimize the generation of the plasma therein. The applicator 1204 provides an interface between the microwaves and a quartz tube 1224 in which the plasma is generated. The plasma is formed within the plasma reaction chamber 1214, which is the region of the quartz tube 1224, where chemical conversion occurs. As shown in the cross - section of FIG. 12, the quartz tube 1224 is disposed within the applicator 1204 but is separated from it by an air gap (not labeled).

[0141] When the plasma is off and the microwave is on, a standing wave is formed in the applicator 1204 between the three-stub tuner 1230 and the sliding shorting plate 1232 on the periphery of the applicator 1204, and the electric field is sufficient to initiate the decomposition of gas molecules in the quartz tube. The microwave energy entering the applicator 1204 uses the shorting plate 1232 to change the phase of the incoming microwave if necessary to change the length of the plasma reaction chamber 1214, and uses the three-stub tuner 1230 to adjust to reach a peak at the center of the plasma reaction chamber 1214. Once the plasma is initiated, the stub positions in the tuner 1230 can be preferentially changed to match the microwave power to the plasma and minimize the unabsorbed power. The three-stub tuner 1230 includes sensors (not shown) for power and phase and can algorithmically adjust the motor-driven stubs to minimize the unabsorbed power. A bi-directional coupler 1234 including two small pinholes connecting microwaves with known attenuation is included in the waveguide 1212 proximal to the three-stub tuner 1230. A power meter (not shown) is connected to these pinhole ports to convert the microwave power to voltage and output forward and reflected power measurements. A thin quartz window 1238 is added to the waveguide system to prevent environmental debris and dust from entering the waveguide components.

[0142] b. Torch System for Acetylene Production In an embodiment, a plasma-based hydrocarbon treatment system for producing acetylene and hydrogen can be of any scale and can deliver a range of purities and acetylene concentrations depending on the desired end use. Plasma-based hydrocarbon treatment systems described previously can be designed for small-scale applications and can be adapted to the needs of the end user. To facilitate this adjustment, the plasma-based hydrocarbon treatment system can be configured such that the effluent (discharge) stream from the reactor is separated into gas streams having different compositions, such as a stream having a higher concentration of acetylene and a stream having a higher concentration of hydrogen. Small-scale plasma-based hydrocarbon treatment systems can be designed to deliver pure gas streams or they can deliver an acetylene-hydrogen mixture with or without other gases present in the product gas flow. Small-scale systems or “mini-units” as described above can be designed to produce only an acetylene-hydrogen mixture within their reactor and the gas effluent can vary from 0.5% to 75% acetylene, so that the amount of separation required is minimized and the complexity of the system is reduced. In an embodiment, the end user can manipulate the parameters of the separation subsystem to produce the desired composition of acetylene mixed with hydrogen; in an embodiment, the parameters of the microwave plasma reactor module in the mini-unit can also be adjusted, although for larger parameter adjustments a larger unit is desirable.

[0143] In one aspect, the overall size of the plasma-based hydrocarbon treatment system can range from smaller units such as table-sized mini units (e.g., 4 feet wide × 8 feet long × 4 feet high) to larger units of 20x20x20 feet or more. In one aspect, the plasma-based hydrocarbon treatment system can be made in a fixed size to be mobile. The desired size of the mobile unit ranges from table-sized dimensions (e.g., 4x8x4) to the size of a standard shipping container. Shipping containers vary in size, but the standard 20-foot ISO shipping container size enables the transport of mobile-sized units; such containers are typically about 8 feet wide, 20 feet long, and 8.5 - 9.5 feet high. Other smaller shipping containers can be used for smaller mobile devices, e.g., having a length of 10 feet or 8 feet, combined with the height and width dimensions described above.

[0144] Such small-scale systems can be attached to small end-user devices (e.g., welding torches such as acetylene or oxyacetylene torches) or small storage facilities or storage tanks. In one aspect, a 5 kW plasma-based hydrocarbon treatment system mini unit having dimensions of 4 feet wide × 8 feet long × 4 feet high can produce an acetylene-hydrogen mixture of more than 50% acetylene in an amount sufficient to fuel at least 5 oxyfuel cutting torches for simultaneous, continuous use. In an aspect, the power range for the plasma-based hydrocarbon treatment system mini unit can range from about 1 kW to about 500 kW, and the power range is selected for the desired commercial application. Plasma-based hydrocarbon treatment systems such as this can be designed to be mobile. As described above, larger units up to the size of a standard ISO 20-foot shipping container, for example, can also be designed to be mobile. In an aspect, the mobile plasma-based hydrocarbon treatment system can be deployed to remote operations such as construction sites, demolition sites, shipyards, or pipeline or offshore oil drilling rigs depending on the availability of a gaseous mixture stream such as natural gas or biogas, electricity, and water.

[0145] FIG. 13 provides a block diagram of a small-scale and scalable plasma-based hydrocarbon treatment system 1300 suitable for industrial applications. As shown in FIG. 13, the plasma reactor 1302, substantially as described above, includes an input supply gas 1304 containing hydrocarbons such as methane, ethane, propane, butane, etc., and derived from a tank or pipeline such as a natural gas line or a biogas tank or line. This input supply gas 1304 has a preselected inflow calibrated from the system 1300 to produce an outflow (discharge) gas flow 1306 ultimately suitable for a particular industrial purpose, such as metal cutting. In an aspect, an inflow supply gas 1304 such as methane or a methane-rich mixture, such as natural gas or biogas, can be used. In an aspect, a liquid supply source of the input supply gas 1304, such as propane or butane, can be advantageous since such a supply gas source can be readily available in certain regions or facilities where natural gas sources, such as natural gas or biogas, are not available.

[0146] In this figure, the direction of gas flow is indicated by arrow 1308 and other arrows in other directions. As an example of a gas flow useful in the system 1300, a gas inflow in the range of about 0 to about 50 SLM can be selected; in one aspect, a gas inflow of 5 SLM can produce a gas outflow of about 10 SLM. In an aspect, the input supply gas 1304 enters the plasma reactor 1302 as the only gas input. In other aspects, another gas input from the recirculation gas flow 1310 enters the plasma reactor 1302 through a separate inlet nozzle (not shown) and is combined with the input supply gas 1304 within the plasma reactor 1302 using, for example, a gas injector (not shown) as described in the previous figures.

[0147] In one aspect, the effluent 1306 from the plasma reactor 1302 contains about 14% acetylene, 84% hydrogen and 2% methane, which can be further processed by other components of the system. Various carbonaceous by-products such as higher carbon products and carbon particles that can be removed prior to delivery of the gaseous product to the end user in certain aspects are included in the gaseous effluent 1306. These by-products can be removed in the solid and liquid traps 1312 and the effluent gas 1306 passes therethrough after being processed in the plasma reactor 1302. After removing the by-products, the gas stream 1306 is processed through a hydrogen separation system 1314 that can include a hydrogen separation membrane system, a short cycle temperature swing adsorber or a pressure swing adsorber that removes hydrogen. Such processing separates the acetylene-rich stream 1318 from the hydrogen-rich stream 1320 and the acetylene-rich stream 1318 is available to the end user for industrial purposes such as metal cutting. In other aspects, for example, when the gaseous emissions are to be used for welding or other industrial applications where a purified acetylene stream is not necessary, there is no advantage in removing the higher carbon products. However, since the higher carbon products can foul the hydrogen separation membrane, these species should be removed when using a hydrogen separation membrane system; alternatively, it is understood that a hydrogen separation system such as a short cycle temperature swing adsorber or a pressure swing adsorber can be used instead of the hydrogen separation membrane system when the mixed exhaust stream containing the higher carbon products is commercially advantageous.

[0148] As shown in the figure, the acetylene-rich stream 1318 that has been treated to remove higher-order carbon products and hydrogen can be directed to various end-users or storage locations 1322. For example, the acetylene-rich stream 1318 can be directed to a pressurized tank from which an end-user can withdraw a gas mixture for use in a metal cutting torch; advantageously, if the acetylene-rich stream 1318 is stored, the plasma-based hydrocarbon treatment system can be carried out intermittently at a required criterion to fill the tank(s) for later use. In one aspect, the acetylene-rich stream 1318 can contain about 50% acetylene along with other components such as hydrogen, methane, and other gaseous additives if applicable. The acetylene-rich stream 1318 can be produced at a flow of about 2.1 SLM. In one aspect, the hydrogen-rich stream 1320 can contain about 4% acetylene and 96% hydrogen and have a total flow of about 7.9 SLM. In an aspect, two or more separation membrane systems can be used to increase the concentration of acetylene in the acetylene-rich product stream 1318, but a small-scale system with a single separation membrane system can be designed to limit the overall size of the apparatus.

[0149] In the aspect of the plasma-based hydrocarbon treatment system illustrated in FIG. 13, the hydrogen-rich stream 1320 can be directed through a separator 1322 that can separate the hydrogen-rich stream 1320 into two sub-streams 1320a and 1320b, where one (1320a) is for end-use, disposal, and / or storage, and one (1320b) is for recirculation as a recirculation gas stream 1310 to the plasma reactor 1302 where the recirculation gas stream can be processed with the input feed gas 1304. The separator 1322 can be formed of components well known to those skilled in the art, such as a Y-valve, a mass flow controller, etc. The non-recirculated hydrogen-rich sub-stream 1320a can be used for discharge, disposal, collection, combustion, or otherwise if required by a particular industrial setting.

[0150] The hydrogen-rich substream 1320b used for recirculation may have the same composition as the substream 1320a that is directed towards end use, disposal and / or storage. In one aspect, a recirculation flow 1310 of about 5 SLM having a composition of about 97.5% hydrogen and 2.5% acetylene may be redirected back to the plasma reactor 1302, resulting in a recirculation flow of about 5 SLM of hydrogen. The recirculation flow 1310 is combined with the input feed gas 1304 to fuel the chemical conversion in the plasma reactor 1302 to produce the effluent gas 1306 as described above. In an aspect, the rate of recirculation may be adjusted based on the requirements of the user. For recirculation, a mass flow controller that measures the amount of hydrogen-rich gas 1320b for recirculation provides a certain consistency and the remainder is directed towards end use, disposal or storage.

[0151] FIG. 14 shows in more detail a modular plasma-based hydrocarbon treatment system 1400 suitable for small or large scale use, with the arrows indicating the direction of gas flow. As shown in FIG. 14, a gas pipeline 1404, such as a natural gas pipeline, can provide the inlet gas for the microwave plasma reactor 1402, although any source of inlet gas (e.g., a supply tank containing gas such as is available for C1-C4 alkanes or a line or tank delivering biogas) can be used. The inlet gas can be supplemented by a recycle stream 1408 containing a hydrogen-rich gas. After treatment in the microwave plasma reactor 1402, the effluent (discharge) gas passes through a heavy liquid trap 1412 that uses a combination of a cold trap and / or a carbon adsorber to remove higher hydrocarbons. As a next step, the effluent gas passes through a filter 1414 that removes particulate matter, such as carbon soot. The gas pressure is then adjusted by a vacuum pump 1418 and the gas is then compressed by a compressor 1422 and passed through a hydrogen separator 1424. The plasma reactor 1402, the heavy liquid trap 1412, the solid filter 1414 and the vacuum pump 1418 are grouped together as a reactor subsystem 1420. This can be located in the vicinity of the hydrogen recycle subsystem 1410 and the effluent management subsystem 1434, or these subsystems can be in fluid communication with each other but can be located remotely from each other for convenience in a particular industrial application.

[0152] As previously described, the hydrogen separator 1424 can include one or more hydrogen separation units; in an exemplary embodiment, each hydrogen separation unit can include one or more hydrogen separation membranes, although other configurations and separator technologies (e.g., the previously described short cycle temperature swing adsorber or pressure swing adsorber technologies for separating hydrogen) can be used. The configuration of the hydrogen separator unit can be adapted to allow for more or less acetylene enrichment in the effluent acetylene-rich stream 1428. Depending on the desired industrial application, this effluent stream 1428 can be used directly as a cut stream or it can be stored as a product stream. In one embodiment, the gas remaining after removing the acetylene-rich stream 1424 contains a high percentage of hydrogen. As previously described, this hydrogen-rich stream can be separated into two sub-streams in the separator 1432, one stream 1408 designated for recirculation and one stream 1430 for disposal, venting, combustion, commercialization or other uses as desired.

[0153] The substantially previously described effluent management subsystem can be integrated with a reactor subsystem (such as a gas delivery subsystem, a microwave subsystem and a vacuum subsystem, etc., previously described but not shown in FIG. 14) within a single mini-unit for a particular application. The size, number and complexity of the components required for the effluent separation process can affect the overall size of the system. In one embodiment, a single plasma reactor can utilize a single hydrogen separation subsystem to provide a small footprint, the subsystem including one or two hydrogen separation membranes or other separation subsystem technologies, such as pressure swing adsorption. In one embodiment, for example, a separation subsystem for hydrogen separation can be integrated with a plasma-based hydrocarbon processing system.

[0154] In an embodiment of a modular plasma-based hydrocarbon processing system using a single hydrogen separation unit having a single separation membrane, the effluent gas from the reactor may contain the following gas components at a flow rate of 10 SLM: 14% acetylene, 81% hydrogen, 2% methane, and 3% nitrogen. After treatment by a hydrogen separation unit having a single separation membrane, a hydrogen-rich stream containing the following gas components at a flow rate of 7 SLM: 4% acetylene and 96% hydrogen is formed. At the same time, an acetylene-rich stream containing the following gas components at a flow rate of 3 SLM: 50% acetylene, 27% hydrogen, 9% methane, and 14% nitrogen is formed. Using this process, 93.75% acetylene retention is achieved in the acetylene-rich stream and 86.5% of the hydrogen is recycled. The flow rates and molar ratios of the components of the various gas streams for one membrane hydrogen separation system are shown in Table 3 below: [Table 3]

[0155] The dual membrane hydrogen separation unit can extract more hydrogen from the effluent gas of the reactor, producing a hydrogen-rich stream containing 1.2% acetylene and 98.8% hydrogen at a flow of 7 SLM. Using this system, an acetylene-rich stream containing the following gas components at a flow rate of 3 SLM: 45% acetylene, 38% hydrogen, 7% methane, and 10% nitrogen is formed. The flow rates and molar ratios of the components of the various gas streams for the two-membrane hydrogen separation system are shown in Table 4 below: [Table 4]

[0156] For small-scale or modular plasma-based hydrocarbon processing systems as described herein, various industrial applications can be envisioned. As noted above, the major industrial use of acetylene is in the metalworking industry, such as metal cutting. For these purposes, a plasma-based hydrocarbon processing system appropriately sized as per this disclosure can be used directly or via a storage tank to provide fuel for metal cutting. Also, the plasma-based hydrocarbon processing system can be coupled with other systems to provide product versatility and increase efficiency in the metalworking industry. As an example, in an oxy-acetylene steel cutting facility, the plasma-based hydrocarbon processing system can be used with an air separation unit (ASU). The ASU can separate air into nitrogen-rich and oxygen-rich streams, which can then be combined with the gas stream(s) used or produced by the microwave plasma reactor unit. Using this combination of devices, an operator can produce all the gas feedstocks required for on-site steel production.

[0157] 4. Integrated Industrial Applications In an aspect, a plasma-based hydrocarbon processing system for making acetylene and hydrogen as described above can deliver any of these products to a subsystem for further processing, thus constructing a fully integrated industrial application that integrates precursor production (i.e., acetylene and / or hydrogen made by the plasma-based hydrocarbon processing system) and precursor utilization to form industrially useful products.

[0158] a. Vinyl Chloride Monomer (VCM) Production As an example, acetylene made by a plasma-based hydrocarbon processing system can serve as a precursor for other industrial processes such as VCM production. A plasma-based hydrocarbon processing system as described above can be modified so that it maximizes and optimizes the acetylene produced and can be integrated with these processes required to convert acetylene to VCM.

[0159] In an exemplary embodiment, an integrated process for VCM manufacturing can be envisioned as described in FIG. 15A. As shown in FIG. 15A, system 1500 for VCM production can be based on a plasma-based hydrocarbon processing system using certain components of the previously described plasma-based hydrocarbon processing system. More specifically, FIG. 15A shows system 1500 for VCM production including a plasma-based hydrocarbon processor 1502, a VCM reactor 1506, and a plurality of separators 1520, 1522, and 1524. The plasma-based hydrocarbon processor 1502 operates in a sustained manner according to the principles described and illustrated in the figures above; this can use any of the plasma-based hydrocarbon processing systems described herein. When integrated with the other components of the VCM production system 1500, the plasma-based hydrocarbon processor 1502 is responsible for converting one or more inlet gases into a mixture of gaseous products contained in the effluent stream exiting the plasma reaction chamber, where the plasma reaction chamber contains a plasma created by a microwave subsystem. Details of these components of the plasma-based hydrocarbon reactor are described herein and are substantially similar to similar components illustrated in previous figures.

[0160] Aspects of a plasma-based hydrocarbon processor 1502 suitable for use with an integrated VCM fabrication system 1500 are shown in more detail in FIG. 15B. The aspects shown in FIG. 15B illustrate an example of a plasma-based hydrocarbon processor 1502 suitable for use with the integrated VCM fabrication system shown in FIG. 15A. Other aspects of the plasma-based hydrocarbon processors described herein may also be used with the VCM fabrication system 1500. FIG. 15B shows a plasma-based hydrocarbon processor 1502 having a gas delivery subsystem 1510 that delivers one or more inlet gases 1504a, 1504b, 1504c to a plasma reaction chamber 1514, where the inlet gases are energized by a microwave subsystem 1508 to form a plasma, and the plasma produces chemical products exiting the plasma reaction chamber 1514 to form an effluent stream (or exhaust stream) 1512 of the effluent gas product. The effluent stream (or exhaust stream) 1512 is then subjected to downstream processing 1510 described in more detail in connection with FIG. 15A. The inlet gases 1504a, 1504b, 1504c can all include hydrogen gas, hydrocarbons such as methane (either in pure form or as components of gaseous mixtures such as natural gas), and other gases, as previously described for the plasma-based hydrocarbon processing systems disclosed herein. In an aspect, one or more of the inlet gases 1504a, 1504b, and 1504c can be recycle gases. The effluent stream 1512 includes acetylene and hydrogen as previously described for various aspects of the plasma-based hydrocarbon processing systems above.

[0161] Returning to FIG. 15A, the plasma-based hydrocarbon processor 1502 receives one or more inlet gases 1504a, 1504b, 1504c, at least one of which is a hydrocarbon gas, such as methane. In an aspect, the inlet hydrocarbon gas can be natural gas as described above for the plasma-based hydrocarbon processing system, which includes methane. Other products including acetylene, hydrogen, higher acetylenes, and higher order hydrocarbons (collectively (C3 +An effluent stream (or discharge stream) 1512 containing a mixture of (( is being released from a plasma-based hydrocarbon processor 1502. To prepare the effluent stream 1512 for use in the VCM reactor 1506, the effluent stream 1512 passes through a first separation system 1520 which is a first plurality of separators that removes higher acetylenes and aromatics (C3 + ) from the effluent stream 1512 to produce a purified discharge stream 1530 which is delivered to the VCM reactor 1506. A stream of hydrogen chloride gas 1526 is also delivered to the VCM reactor 1506. The acetylene contained in the purified discharge stream 1530 combines with hydrogen chloride gas 1524 in the VCM reactor 1506 as shown by the following formula: [Chemical formula] to produce VCM

[0162] A VCM reactor effluent 1528 entering a second separation system 1522 exits the VCM reactor 1506. This second separation system 1522 is a compression system including a compressor 1522a for compressing the VCM reactor effluent 1528 and a cold chamber 1522b for lowering the temperature of the VCM reactor effluent 1528, which can condense VCM as a liquid from the VCM reactor effluent 1528 and then remove this as a liquid form 1536 of VCM from the fluid stream by a liquid-gas separator 1522c. The cold chamber 1522b can be operated by circulating a coolant 1522d or any other mechanism well known to those skilled in the art. A stream of residual gas 1532 exits the liquid-gas separator 1522c for further processing by a third separation system 1524 which separates purified hydrogen from the residual gas 1532 leaving a gas stream 1538 that can be recycled to the plasma-based hydrocarbon processor 1502.

[0163] In one aspect, the plasma-based hydrocarbon processor 1502 can be configured substantially in the form of the 100 kw plasma-based hydrocarbon processing system described above; while this system is described as having 100 kW of magnetron power, it is understood that other amounts of power for the system can also be used to power the plasma-based hydrocarbon processor. In this exemplary aspect, the inlet gases 1504a and 1504b for the plasma-based hydrocarbon processor are natural gas (mostly methane) and recycle gas (mostly hydrogen). These inlet gases 1504a and 1504b react within the plasma-based hydrocarbon processor 1502 to produce acetylene in the outlet stream 1512. As already detailed above with respect to plasma-based hydrocarbon reactor technology, the outlet stream 1512 also contains other substances including hydrogen, higher acetylenes, aromatics, etc. Therefore, the outlet stream 1512 is processed by a first separation system 1520 to remove higher hydrocarbons such as higher acetylenes and aromatics (C3 + ). As described above, the effluent separation subsystem suitable for use as a component of the first separation system 1520 can include a prescrubber, a temperature swing adsorber, etc. As a result of its encounter with the first separation system 1520, the outlet stream 1512 diverging from the plasma-based hydrocarbon processor 1502 is free of these higher hydrocarbons (C3 +) is purified and exits as purified effluent stream 1530. The purified effluent stream 1530 is combined with hydrogen chloride gas 1526 within VCM reactor 1506, where the reaction between the two gases is catalyzed to form VCM; the VCM thus formed is discharged from the VCM reactor in VCM reactor effluent 1528, which is a VCM-containing gas stream. The VCM reactor effluent 1528 is then processed by a second separation system 1522, which compresses liquid VCM 1536 and passes the residual gas 1532 to a third separation system 1524, which provides a hydrogen separator that separates purified hydrogen product 1534 from the recycle gas stream 1538 and returns it to reactor 1502. The hydrogen separator can be, for example, an H2 membrane, an H2 pressure swing adsorber, or other techniques described herein for hydrogen separation. System 1500 for VCM production is illustrated by reference to the 100 kw plasma-based hydrocarbon treatment system described above, although other versions of the plasma-based hydrocarbon treatment systems disclosed herein are also understood to be suitable for use in this integrated system and method. System 1500 for VCM production can use a plasma-based hydrocarbon treatment system of any scale and is understood to deliver a range of purities and acetylene concentrations. By way of example, the plasma-based hydrocarbon treatment system described above for small-scale applications can be used in conjunction with the system for VCM production.

[0164] Figure 16 shows an alternative embodiment of a system for the production of VCM integrated with a plasma-based hydrocarbon treatment system using certain components of the plasma-based hydrocarbon treatment system already described. More specifically, FIG. 16 shows a system 1600 for the production of VCM that includes a plasma-based hydrocarbon processor 1602, a VCM reactor 1606, and a plurality of separators 1620, 1622, and 1624. The plasma-based hydrocarbon processor 1602 operates according to the principles described and illustrated in the figures above; this may use any of the previously described plasma-based hydrocarbon treatment systems. When integrated with the other components of the VCM production system 1600, the plasma-based hydrocarbon processor 1602 is responsible for converting one or more inlet gases 1604 into a mixture of gaseous products contained in the effluent stream exiting the plasma reaction chamber (not shown), where the plasma reaction chamber contains a plasma generated by a microwave subsystem (not shown). The details of these components of the plasma-based hydrocarbon reactor are described above and are substantially similar to the similar components illustrated in the previous figures. However, the components of system 1600 are substantially similar to those illustrated in FIGS. 15A and 15B, but their arrangement is different. As shown in FIG. 16, the inlet gas 1604 enters the plasma-based hydrocarbon processor 1602, where it is mixed with any other inlet gases (such as the recycle gas 1638) and converted into an acetylene-containing exhaust stream 1612 through its encounter with the plasma within the plasma-based hydrocarbon processor 1602. The exhaust stream 1612 then passes through a first separation system 1620, where higher hydrocarbons (C3 +)(e.g., acetylene and aromatic compounds) are removed. The purified exhaust stream 1630 exiting the first separation system 1620 passes through a second separation system 1624, which separates hydrogen from the fluid stream. The hydrogen can be recycled 1638 to the plasma-based hydrocarbon processor 1602 for further reaction there. The hydrogen separation system 1624 also produces a concentrated exhaust stream 1640 containing acetylene, which can then react with hydrogen chloride gas 1626 in the VCM reactor 1606 to produce VCM. The VCM reactor effluent 1628, which is a VCM-containing gas stream, then enters a third separation system 1622, which compresses the VCM through a series of components substantially similar to those described in FIG. 15A from the VCM reactor effluent 1628. More specifically, this third separation system 1622 includes a compressor 1622a for compressing the VCM reactor effluent 1628 and a refrigeration chamber 1622b for lowering the temperature of the VCM reactor effluent 1628, compressing the VCM from the VCM effluent as a liquid, which can then be removed from the fluid stream by a liquid-gas separator 1622c as another liquid VCM product 1636. The refrigeration chamber 1622b can be operated by circulating a coolant 1622d or any other mechanism well known to those skilled in the art. The residual gas stream 1632 exiting the liquid-gas separator 1622c mainly contains hydrogen, and the residual gas stream 1632 can then be discarded or further processed through a hydrogen separator (either by routing it (not shown) to the previously described hydrogen separator 1624 or another hydrogen separator not shown).

[0165] Figures 15A and 16 each show a VCM reactor (1506, 1606) for converting acetylene and hydrogen chloride gas to VCM. An exemplary embodiment of a VCM reactor for use with the above-described system and method for VCM production is shown in more detail in FIG. 17. The VCM reactor 1700 includes an outer housing 1702 in which a catalyst bed is supported, and in the various ways shown, it is formed of a plurality of catalyst-containing cylindrical tubes 1704. The housing can be made of stainless steel or any other suitable material known in the art. The catalyst-containing tubes 1704 can be made of glass or any other suitable material known in the art. A plurality of catalyst pellets are deployed within the catalyst-containing tubes 1704 to form a packed bed 1708. Each of the catalyst pellets 1710 includes a support 1710a attached to or in the vicinity of a plurality of catalyst particles 1710b; the support 1710a is configured with holes 1710c through which at least some of the purified effluent stream containing acetylene passes and contacts the catalyst particles, thereby increasing the surface area over which reactants can contact the catalyst particles 1710b. Reactants 1712 (acetylene and HCl gas) enter the proximal end 1714 of the catalyst-containing tubes 1704 and pass distally through the tubes 1704 to their distal ends 1718. As the reactants 1712 pass through the tubes 1704, they contact the catalyst particles therein and undergo a catalytic reaction to form the desired product VCM 1720. The VCM 1720 exits from the distal end 1718 of the catalyst-containing tubes 1704. A high reaction temperature may be desirable, in which case heated oil or any other heated substance can be circulated within the reactor to surround the catalyst-containing tubes 1704. In the embodiment shown, hot oil 1728 enters at an inlet 1722 located in the distal portion of the reactor housing 1702 and exits at an outlet 1724 located in the proximal portion of the reactor housing 1702. In an embodiment, a temperature of the hot oil of 150-220 °C is advantageous. Other temperatures can be maintained by appropriately varying the temperature of the circulating heating or cooling substance. Other modifications to the reactor design can be substituted for this example without departing from the spirit and scope of the disclosed invention as will be understood by those skilled in the art.

[0166] Catalysts suitable for use with the VCM reactor systems described herein can be prepared by one of ordinary skill in the art according to published procedures such as those described in the following references, which are well known in the art and incorporated herein by reference in their entirety. Examples of catalysts suitable for use with these systems and methods include, but are not limited to: HgCl2 on activated carbon (e.g., as disclosed in U.S. Patent 2446123); Au2(S2O3)3 on activated carbon (e.g., as disclosed in U.S. Patent 9409161), HAuCl4 on activated carbon (e.g., as disclosed in J. Catal., 2013, 297, 128 - 136); AuCl3 on mesoporous carbon materials (e.g., as disclosed in Catal. Sci. Technol., 2015, 5, 1035 - 1040); HAuCl4, H2PtCl6, RhCl3, IrCl3 and / or PdCl2 on activated carbon (e.g., as disclosed in J. Catal., 2008, 257, 190 - 198); CuCl2 and BiCl3 on silica gel (e.g., as disclosed in Fuel Process. Technol., 2013, 108, 12 - 18); (PPh3)AuCl on activated carbon (e.g., as disclosed in Catal. Sci. Technolog., 2016, 6, 7946 - 7955), RuCl3 on activated carbon (e.g., as disclosed in RSC Adv., 2017, 7, 23742 - 23750). Bimetallic catalyst systems for acetylene hydrochlorination are also suitable for use with the VCM reactor systems described herein and include AuCl, AuLa, AuBa, AuNi, AuCs, AuTiO2 and AuCoCu; a description of suitable bimetallic catalyst systems can be found in ACS Catal., 2015, 5, 5306 - 5316.

[0167] b. Vitamin A and E production As another example, acetylene and hydrogen produced by a plasma-based hydrocarbon treatment system can serve as precursors for other industrial processes such as the manufacture of vitamins A and E and their respective chemical intermediates. The plasma-based hydrocarbon treatment system described above can be modified to maximize and optimize the acetylene produced, which can be integrated with these processes required to convert acetylene into these vitamin products. Also, such a system can produce hydrogen that can be used in the manufacture of vitamin products.

[0168] In an aspect, the plasma-based hydrocarbon treatment system for producing acetylene and hydrogen described above can deliver any of these products to a subsystem for further processing, thus constructing a fully integrated industrial application that incorporates precursor products (i.e., acetylene and / or hydrogen produced by the plasma-based hydrocarbon treatment system) and precursor utilization to form industrially useful products. For example, acetylene produced by a plasma-based hydrocarbon treatment system can serve as a precursor for other industrial processes such as the manufacture of vitamins A and E, provitamin β-carotene, and their respective chemical intermediates. Acetylene, along with C3 feedstocks (e.g., acetone, diketene, ethyl acetoacetate, isopropenyl methyl ether) and hydrogen, is a critically important feedstock for the commercial production of vitamins A and E and provitamin β-carotene (collectively "vitamin products"). The plasma-based hydrocarbon treatment system described above can be modified to maximize and optimize the acetylene produced and can be integrated with these processes required to convert acetylene into these products.

[0169] Figure 18 shows a representative multi-step synthetic route that shows chemical intermediates useful for the production of vitamin A and E and provitamin β-carotene. From the perspective of the overall mass balance, 1 kg of vitamin product consists of 0.25 kg C2H2 in vitamin E, 0.27 kg C2H2 in vitamin A, and 0.29 kg C2H2 in β-carotene. The synthetic route 1800 shown in Figure 18 enables the synthesis of vitamin products using acetylene as the main hydrocarbon component. As shown in Figure 18, a common starting route (1800a including steps 1802, 1804, 1808) produces a common precursor, dehydro linalool, which is then converted to vitamin E via route 1800b (including steps 1810, 1812, 1814, 1818, 1820, and 1822), or is then converted to vitamin A via route 1800c (including steps 1824 or alternatively steps 1830 and 1832, then steps 1828, 1838, and 1840; step 1834 shows the route by which the precursor of step 1838 is formed). As used herein, the term "vitamin A" refers to and includes the four main forms of vitamin A: retinal, retinol, retinoic acid, and retinyl esters (e.g., retinol acetate). For the sake of brevity, the structure of vitamin A is shown as retinol in Figures 18, 19, and Table 5 (below). β-carotene is formed from vitamin A as schematically shown in step 1840.

[0170] In the first step of the common starting pathway 1800a (step 1802), there are two other reaction sequences up to this step: ethynylation and hydrogenation. The former involves reacting acetone with acetylene in the presence of a base / solvent combination (as described below). In this step, the peripheral hydrogen atoms of acetylene are deprotonated by the base, and the acetylide is bonded to the carbonyl of acetone. As shown in this figure, the second sequence after ethynylation is hydrogenation with Lindlar catalyst to hydrogenate the alkyne to an alkene moiety. Overall, step 1802 yields 2-methylbut-3-en-2-ol, which reacts with isopropenyl methyl ether in step 1804 to form 6-methylhept-5-en-2-one. In step 1808, acetylene reacts with 6-methylhept-5-en-2-one (from step 1804) to yield dehydrolinalool, which is a common precursor for pathways 1800b and 1800c. For convenience, the names of the reagents, intermediates, and products shown in Figure 18 are listed in Table 5. Note that the chemical structures shown in Figures 18 and 19 and Table 5 do not refer to specific E / Z and R / S stereoisomer configurations for their respective chemical names. For the sake of brevity, only a single stereoisomer structure is shown in the figures and tables. Furthermore, it is understood by those skilled in the art that the chemical names used herein refer to all possible stereoisomers, including but not limited to single stereoisomers, non-racemic mixtures of stereoisomers, and racemic mixtures of stereoisomers of the same compound.

Table 5-1

Table 5-2

[0171] The following route 1800b results in the formation of vitamin E through steps 1810, 1812, 1814, 1818, 1820 and 1822. More specifically, step 1810 hydrogenates dehydro linalool in the presence of Lindlar's catalyst to form linalool. Step 1812 combines linalool and isopropenyl methyl ether to form 6,10-dimethylundeca-5,9-dien-2-one. In step 1814, this product is first reacted with acetylene and then catalytically hydrogenated to yield 3,7,11-trimethyldodeca-1,6,10-trien-3-ol. This product is then reacted with 2-methoxy-1-propene (step 1818), forming a product which is reacted with acetylene and then catalytically hydrogenated (step 1820) to form 3,7,11,15-tetramethylhexadec-1-en-3-ol, which is converted via step 1822 by catalytic Friedel-Craft alkylation to form vitamin E according to the procedure described in CHIMIA 2014, 68, 485-491, the content of which is hereby incorporated by reference. Route 1800c results in the formation of vitamin A through step 1824 (or alternative steps 1830 and 1832) and through steps 1828 and 1838. Either step 1824 or steps 1830 and 1832 result in the formation of pseudoionone, which can then be converted to β-ionone by acidification as shown in step 1828. To form pseudoionone in step 1824, isopropenyl methyl ether is added to dehydro linalool. Alternatively, pseudoionone is formed through steps 1830 and 1832 by first converting dehydro linalool to citral by an internal rearrangement process using a vanadium catalyst and then combining citral and acetone to yield pseudoionone. Pseudoionone can then be converted to β-ionone by acidification in step 1828. Once β-ionone is formed, it can be combined with 3-methylpenta-2-en-4-yn-1-ol (formed from acetylene and methyl vinyl ketone in step 1834) to yield vitamin A.Vitamin A can, in turn, be used as a precursor to other molecules, such as β-carotene, schematically shown by step 1840.

[0172] The complex synthetic pathways underlying vitamins / provitamins, as shown in Figure 18, are controlled ethynylation reactions where acetylene selectively adds a methyl ketone group. These reactions proceed by the single deprotonation of the C-H bond of acetylene by a strong base, followed by the addition of a ketone electrophile (e.g., acetone) and C-C bond formation, as illustrated in the following formula

Chemical formula

[0173] Often, only a catalytic amount of base needs to be added to the reactor to effect the necessary deprotonation. In commercial applications, potassium hydroxide and liquid ammonia are the preferred base / solvent combination, as shown above. Other base / solvent combinations that can be used for the ethynylation reaction include, but are not limited to, potassium hydroxide / dimethyl sulfoxide, sodium / methanol, potassium hydride / tetrahydrofuran, and sodium amide / diethyl ether. The base-mediated reaction occurs once per acetylene molecule, preventing overalkylation of acetylene. This simple stepwise reaction is repeated several times in the sequence of ethynylation, hydrogenation, and condensation reactions, as shown in Figure 18, to build the long terpeneoid structure that forms the backbone of the final vitamin product. These ethynylation reactions can typically be carried out batchwise or semi-continuously using sodium hydroxide in ammonia, which deprotonates acetylene and catalytically operates to reduce the amount of base required.

[0174] Figure 19 shows the same multi-step synthesis 1900 as shown in Figure 18, with specific details in paths 1900a, 1900b, and 1900c emphasized for clarity. In this figure, dashed boxes are placed in the reaction structure to indicate these carbon atoms contributed by acetylene to the synthesis intermediates and the final product, and solid boxes are placed around the acetylene molecule itself. The illustration in Figure 19 schematically shows the centrality of acetylene to the synthesis of the vitamin product. In Figure 19, the incorporation of acetylene is seen in steps 1902, 1908, 1914, 1920, and 1934. The acetylene for each of these steps can be provided by the plasma-based hydrocarbon treatment system described herein.

[0175] A schematic example of such a plasma-based hydrocarbon treatment system useful for producing acetylene and hydrogen for vitamin production was previously described with respect to Figure 9. As previously shown in Figure 9 above and described in more detail herein, the inlet gas streams 912 and 914 are processed in reactor 902 to form an outlet stream 918 that includes acetylene, hydrogen, and a small percentage of mixed hydrocarbons. The outlet stream 918 is then separated into gaseous components via a gas separation system 928 (e.g., adsorption, absorption, or a combination thereof), resulting in an acetylene stream 920 and a hydrogen-dominant gas stream 922 that includes a mixture of hydrogen 936 and hydrocarbon 924. Thus, when diverted from the main outlet stream 918 by the gas separation system 928, the acetylene stream 920 can be purified by further isolation of impurities in a purification system 926 to yield a purified acetylene gas product 932. The purified acetylene gas product 932 is available for use in further industrial processes such as the synthesis of the vitamin products shown in Figures 18 and 19.

[0176] Using the systems and methods disclosed herein, acetylene and hydrogen can be produced on-site from natural gas or other hydrocarbon feedstocks and used in the manufacture of vitamins and provitamins. These systems and methods can enable vitamin manufacturers to control their own acetylene production capabilities and resource utilization while providing a source of high-purity acetylene.

[0177] Figure 20 shows a general scheme of the steps of a process for making vitamin product 2000 using acetylene and hydrogen produced by a plasma-based hydrocarbon treatment system disclosed herein. The scheme shown in Figure 20 can utilize various plasma-based hydrocarbon treatment systems such as those disclosed herein, and acetylene and / or hydrogen are produced using such a system, and then such produced gas(es) are used in whole or in part to make the vitamin product. Note that pathway 2002a shows the steps for making acetylene from a raw material according to these systems and methods. As a starting step, a raw material is provided 2004 for further processing, where the raw material includes a hydrocarbon-containing inlet gas and may further include a recycle gas. The raw material is then processed 2008 in a reactor having a gas delivery subsystem, a plasma reaction chamber, and a microwave subsystem as previously described, into an outlet gas product containing acetylene, hydrogen, and acetylene by-products, and the acetylene, hydrogen, and by-products are discharged from the reactor and enter a set of separators for further separation and purification steps 2010. In an aspect, the step of processing 2008 includes injecting the hydrocarbon-containing inlet gas into the plasma reaction chamber; energizing the hydrocarbon-containing inlet gas in the plasma reaction chamber with microwave energy to generate a plasma; forming an outlet gas product in the plasma, where the outlet gas product includes acetylene and hydrogen; and flowing the outlet gas product out of the plasma reaction chamber (not shown), where the outlet gas product is processed by a set of separation and purification steps 2010. The separation and purification steps 2010, including the steps of exhaust separation, acetylene separation, and hydrogen separation, result in a set of component gases including a pure acetylene product 2012, and then the pure acetylene product 2012 is distributed 2016 to enter the process for vitamin production 2018. The separation and purification steps also result in off-gases 2014 such as acetylene by-products removed or isolated from the pure acetylene product 2012 and pure hydrogen.

[0178] As described above, the pure acetylene product 2012 made by the separation and purification process 2010 is distributed 2016 for further use in vitamin production 2018. The pure acetylene may be distributed 2016 via direct delivery 2024 (i.e., with no intermediate diversion or sequestration of the gas) for this purpose; the pure acetylene product 2012 may also be distributed 2016 for storage 2022 or for a commercialization process such as bottling, either of which purposes are available for subsequent use in vitamin production 2018 (as shown in pathways 2026 and 2028). The distribution process 2016 is intended to optimize utilization of the acetylene generated by the plasma-based hydrocarbon processing pathway 2002a by adjusting the inflow of acetylene 2012 produced through this pathway 2002a to match the process needs for vitamin production 2018, for example via a feedback mechanism, where the inflow of acetylene 2012 is increased or decreased depending on the measurement of required acetylene provided by the vitamin production system. The steps shown by the pathway in 2002b show how the pure acetylene 2012 produced by the plasma-based hydrocarbon processing pathway 2002a may enter a synthesis process for producing the vitamin product 2018. One option includes acetylene bottling 2020, where the pure acetylene 2012 is bottled in compressed form and delivered 2026 to a manufacturing plant for subsequent use in making the vitamin product 2018. However, acetylene bottling 2020, as is well known in the art, is known to have commercially significant drawbacks such as safety concerns and logistical difficulties. A second option involves storage of acetylene in gas holding tanks 2022 at near atmospheric pressure with subsequent delivery 2028 for vitamin production 2018. While this approach offers advantages compared to acetylene bottling 2020, safety concerns and logistical difficulties still exist. Direct delivery 2024 of pure acetylene 2012 for vitamin production 2018 is a highly desirable option.Using the systems and methods disclosed herein and shown in the figures, a predictable source of highly purified acetylene 2012 for use in vitamin production 2018 can be provided, desirably via direct delivery 2024 to the vitamin production process 2018.

[0179] Figure 21 shows in more detail how the systems and methods disclosed herein can be integrated with systems and processes for manufacturing vitamin products. In an aspect, this figure shows how the systems and methods disclosed herein can efficiently generate highly purified acetylene suitable for direct and / or controllable delivery to the manufacturing process, and how the systems and methods disclosed herein can optimize the delivery of acetylene to the vitamin production systems and processes, while minimizing the need for auxiliary storage facilities and in line with the variable demands of these processes.

[0180] Figure 21 shows an embodiment of an integrated acetylene-based vitamin synthesis system 2100, where a plasma-based hydrocarbon processing system 2102 as described herein interfaces with a system 2150 for manufacturing vitamin products 2106, such as the vitamin products shown in the synthesis diagrams of FIGS. 18 and 19 or precursors thereof. In the embodiment shown, the vitamin manufacturing system 2150 includes a vitamin reaction plant 2104, a control system (or "controller") 2116, an acetylene storage 2142, and a hydrogen storage 2144. In the embodiment shown: (i) the reactions described in FIGS. 18 and 19 for the production of vitamin product 2106 are carried out by appropriate reactors (not shown) within the vitamin reaction plant 2104; (ii) the acetylene storage 2142 and hydrogen storage 2144 are available for storing acetylene and hydrogen gas produced by the plasma-based hydrocarbon processing system 2102 or obtained from other sources; (iii) the controller 2116 controls the flow of acetylene and hydrogen from the plasma-based hydrocarbon processing system 2102 to the vitamin reaction plant 2104 and / or, if necessary, to the storages 2142 and 2144. The embodiment shown includes storages 2142 and 2144, but it is understood that the plasma-based hydrocarbon processing system 2012 disclosed herein can also provide acetylene and / or hydrogen for direct delivery as described above without the need for storages or other containers for storing excess gas. In such an embodiment, the controller 2116 controls the flow of acetylene and hydrogen from the plasma-based hydrocarbon processing system 2102 to the vitamin reaction plant 2104 without intermediate routing changes or isolation of the gas(es), for example, from each of the acetylene and hydrogen separators. It is further understood that other arrangements or components for the vitamin manufacturing system 2150 can be envisioned by those skilled in the art as embodiments of the integrated acetylene-based vitamin synthesis system 2100 that use a plasma-based hydrocarbon processing system 2102 as described herein.

[0181] With more particular reference to FIG. 21, the plasma-based hydrocarbon processing system 2102 produces a highly purified acetylene product 2108 that can be delivered to a system 2150 for manufacturing vitamin products 2106. In the illustrated embodiment, the plasma-based hydrocarbon processing system 2102 includes a microwave reactor 2114 that includes a hydrocarbon inflow stream 2110 (e.g., natural gas) and a recycle gas stream 2112, and a plasma reaction chamber (not shown) to which the hydrocarbon inflow stream 2110 and the recycle gas stream 2112 are delivered, where they are energized by a microwave subsystem (not shown) to form a plasma that produces chemical products exiting the plasma chamber, forming an effluent stream 2118 of the effluent gas product, all as described in detail above. In the illustrated embodiment, the effluent stream 2118 is subjected to further processing and separation, such as passing through a set of separator subsystems.

[0182] The set of separator subsystems, all of which have been described in more detail previously, are: (i) an exhaust separator 2120 for the removal of higher acetylenes and aromatic impurities (C3 + ) (e.g., using a temperature swing adsorber or a prescraber) to produce a purified exhaust stream 2122; (ii) an acetylene separator 2124 for the separation of the highly purified acetylene product 2108 from the purified exhaust stream 2122 through an acetylene purification column or the like to produce a residual exhaust stream 2128; and (iii) a hydrogen separator 2130 (e.g., a pressure swing adsorber or a membrane separator).

[0183] The embodiment shown in FIG. 21 provides one sequence of the separator process and the subsystem. In the embodiment shown, the residual exhaust stream 2128 is split into two streams 2128a and 2128b. The first residual exhaust stream 2128a undergoes further treatment in the hydrogen separator 2130, from which a purified hydrogen product 2132 is separated. The other residual exhaust stream 2128b is diverted before entering the hydrogen separator 2130 and instead recycled to form a recycle gas stream 2112 (either alone or combined with other gas streams such as the residual gas stream 2136 discharged from the hydrogen separator 2130 as shown), and the recycle gas stream 2112 is available for use in the microwave reactor 2114 as previously described. The residual gas stream 2136 can be used to form the recycle gas stream 2112 either by being mixed with other recyclable gas streams such as the residual exhaust stream 2128b (as shown in this figure) and / or combined with other gas streams (not shown), or can be used alone to form the recycle gas stream 2112.

[0184] The purified hydrogen product 2132 can be directed in a hydrogen stream 2132a dedicated for final use in the vitamin reaction plant 2104; alternatively, the purified hydrogen product 2132 can be directed away from the vitamin production system 2150 in an external hydrogen stream 2132b for other sales, storage, or disposal. More specifically, the purified hydrogen product 2132a can be directed by the controller 2116 to a holding tank or other storage 2144 for use in the vitamin reaction plant 2104. The storage 2144 can be configured as a holding tank for primary storage, where the purified hydrogen 2132d is present at a preselected time based on the needs of the overall vitamin production system 2150. Similarly, the purified acetylene product 2108 can be directed in a dedicated acetylene stream 2108a for use in the vitamin reaction plant 2104; alternatively, the purified acetylene product 2108 can be directed away from the vitamin production system 2150 in an external acetylene stream 2108b for other sales, storage, or disposal. More specifically, the purified acetylene product 2108a can be directed to a holding tank or other storage 2142 for use in a system for producing vitamin products. The storage 2142 can be configured as a holding tank for primary storage, where the purified acetylene 2108d is present at a preselected time based on the needs of the overall vitamin production system 2150.

[0185] In an embodiment, the controller 2116 is arranged to receive acetylene and hydrogen from dedicated acetylene stream 2108a and dedicated hydrogen stream 2132a, respectively, and to deploy these reactants for use in the vitamin production system 2150. As shown in the schematic, the controller 2116 can pass the purified acetylene 2108 through the acetylene inflow stream 2108c to the vitamin reactor plant 2104, where the acetylene inflow stream 2108c includes the purified acetylene product 2108 produced by the plasma-based hydrocarbon treatment system 2102. Further or alternatively, the controller 2116 can redirect some or all of the purified acetylene 2108 via the storage circuit 2108d to the storage 2142 for temporary storage, and the controller can direct the release of the purified acetylene from the storage 2142 via the storage circuit 2108d so that it enters the acetylene inflow stream 2108c for use in the vitamin reactor plant 2104 to produce the vitamin product 2106. Similarly, as shown in the schematic, the controller 2116 can pass the purified hydrogen 2132 through the hydrogen inflow stream 2132c to the vitamin production system 2104, where the hydrogen inflow stream 2132c includes the purified hydrogen product 2132 produced by the plasma-based hydrocarbon treatment system 2102. Further or alternatively, the controller 2116 can redirect some or all of the purified hydrogen 2132 via the storage circuit 2132d to the storage 2144 for temporary storage, and the controller can direct the release of the purified hydrogen from the storage 2144 via the storage circuit 2132d so that it enters the hydrogen inflow stream 2132c for use in the vitamin reactor plant 2104 to produce the vitamin product 2106. Each of the storages 2142 and 2144 can further be in fluid communication with an external flow for its respective gas component (for acetylene 2108b and for hydrogen 2132b) via offload conduits (shown as dashed line 2146 for acetylene and dotted line 2148 for hydrogen).

[0186] The purified acetylene 2108 stored in the storage 2142 can be dissolved in a solvent within the storage 2142, such as solvents like N-methylpyrrolidone and dimethylformamide and / or liquid ammonia. In an aspect, the acetylene gas 2108d directed towards the storage 2142 is compressed via a compressor (not shown) before reaching the storage 2142, so that the storage 2142 can provide sufficient storage for the needs of the manufacturing facility in a smaller space. In an aspect, the acetylene gas 2108d can be compressed via a compressor (not shown) together with an inert carrier gas or a non-inert gas such as gaseous ammonia towards the storage 2142, or the acetylene gas 2108d can be compressed into a non-inert gas such as an inert carrier gas or gaseous ammonia already contained in the storage 2142. In an aspect, the acetylene 2108a can be directed by the controller 2116 to bypass the storage 2142 and can be directed as a direct delivery distribution to the vitamin reactor plant 2104 via the acetylene inflow stream 2108c; in other aspects, the acetylene 2108 required for the various steps of vitamin synthesis is obtained from the acetylene stored in the storage 2142, and the acetylene is directed by the controller 2116 from the storage 2142 to the vitamin reactor plant 2104 via the acetylene inflow stream 2108c as controlled by the controller 2116. It is understood that the controller 2116 can control the inflow 2108c of acetylene for vitamin production provided from any available source, such as any combination of the plasma-based hydrocarbon treatment system 2102, the acetylene storage 2142, and any other source (not shown) that provides acetylene of appropriate purity for vitamin production.Since similar sets of options are available for hydrogen, hydrogen 2132a can be directed by controller 2116 to bypass storage 2144 and can be directed as a direct delivery distribution to vitamin reactor plant 2104 via hydrogen inflow stream 2132c; in other embodiments, the hydrogen 2132 required for the various steps of vitamin synthesis is obtained from the hydrogen stored in storage 2144, and the hydrogen is directed from storage 2144 to vitamin reactor plant 2104 by controller 2116 via hydrogen inflow stream 2132c as controlled by controller 2116. It is understood that controller 2116 can control the inflow 2132c of hydrogen for vitamin production from any available source, such as any combination of plasma-based hydrocarbon processing system 2102, hydrogen storage 2144, and any other source (not shown) that provides hydrogen of suitable purity for vitamin production.

[0187] In embodiments, controller 2116 includes a feedback loop or similar processing system(s) that adjusts the rate of the process performed by plasma-based hydrocarbon processing system 2102 to enable the production of just the right amount of purified acetylene 2108 or hydrogen 2132 when required by vitamin production system 2104; for example, in embodiments, controller 2116 enables the intermittent production of purified acetylene 2108 or hydrogen 2132, or controls the rate of their production, or controls the diversion of their paths to an external flow outside the system, such as an external flow of acetylene 2108b or hydrogen gas 2132b. In embodiments, controller 2116 can control the amount of hydrogen extracted from residual exhaust stream 2128a by hydrogen separator 2130 and / or the controller can control the volume of residual exhaust stream 2128 that is diverted to include recirculation gas stream 2112 as 2128b. Other interfaces between controller 2116 and plasma-based hydrocarbon processing system 2102 can be envisioned by one of ordinary skill in the art to synchronize the needs of vitamin reactor plant 2104 with the output from plasma-based hydrocarbon processing system 2102.

[0188] As a further example, in some variations of system 2100, in order to allow for the intermittent production, just-in-time production, or interrupted production of acetylene and / or hydrogen for vitamin production, some variations of system 2100 may be implemented. As shown in FIG. 21, hydrocarbon inlet stream 2110 is energized in microwave reactor 2114 with recycle gas 2112 to produce acetylene and hydrogen in outlet stream 2118. As shown, outlet stream 2118 is further processed to provide purified acetylene 2108 for vitamin production system 2150. If it is necessary to stop the production of acetylene and hydrogen, for example, if the throughput of the gas(es) is not needed for vitamin production and / or sufficient gas(es) has / have been provided for vitamin production and the capacity of storage 2142 and / or 2144 is not suitable for storing excess gas, the power supply to microwave reactor 2114 can be reduced to stop the production of acetylene and hydrogen, which is included as an applicable shutoff of the delivery of hydrocarbon-containing inlet gas 2110. After such a shutoff, recycle gas 2112 can simply be recycled within system 2102 (not shown). In other embodiments, the recycled recycle gas 2112 can also bypass one or more purification steps (e.g., 2120, 2124, and 2130) if necessary. In a preferred embodiment, 2124 and 2130 are bypassed by recycling the recycle gas, and the gas(es) (2128 and 2108) discharged from acetylene purification column 2124 are recycled to re-enter acetylene purification column 2124. The gas flow paths and operating conditions for separating plasma-based hydrocarbon processing system 2102 from vitamin production system 2150 can be coordinated based on the needs of the vitamin production system or other pre-selected parameters.

[0189] In an aspect, the controller 2116 achieves this coordination. The interaction of the components of the integrated acetylene-based vitamin synthesis system 2100 mediated by the controller 2116 causes the supply side of the system (i.e., the plasma-based hydrocarbon treatment system 2102) to respond quickly to the requirements from the demand side of the system (i.e., the vitamin production system 2150), for example, quickly changing the volume of acetylene produced or starting / stopping the production of acetylene and hydrogen and their delivery to the vitamin reactor plant 2104 if necessary or redirecting more or less hydrogen-containing residual effluent stream 2128 for recirculation 2112.

[0190] The processes for the production of vitamins A and E and their precursors are well known to those skilled in the art, and the plasma-based hydrocarbon treatment system 2102 described herein provides some or all of the acetylene and / or hydrogen used in these production processes. Therefore, the synthesis processes for the production of vitamin products 2106 previously shown in FIGS. 18 and 19 are not shown in FIG. 21. However, as an example of how the system of FIG. 21 can perform the synthesis processes of FIGS. 18 and 19, a series of reactors (not shown) can be arranged within the vitamin reactor plant 2104 and filled with appropriate reagents to perform the reactions shown in FIGS. 18 and 19. The acetylene and hydrogen delivered to these reactors can be pre-compressed (not shown) if necessary. In an aspect, the reaction pathway involves the isolation of the reaction products and their further ethynylation and / or hydrogenation according to the steps in the synthesis pathway, with one or more reactions as shown in FIGS. 18 and 19, for example, providing acetylene and / or hydrogen for the ethynylation reaction and hydrogenation reaction if necessary by the steps of the synthesis pathway, and can be provided within the vitamin production system 2150.

[0191] Figures 20 and 21 show a particular order of the separator subsystem, but it is understood that in other embodiments, the ordered positions of the effluent separator, acetylene separator, and hydrogen separator may be rearranged. Figure 22 shows one arrangement of these components. As shown in Figure 22, the inflow 2206 from the plasma-based hydrocarbon treatment system 2200 described above first enters the effluent separator 2202 (collectively forming block A in the figure) for the removal of higher acetylene and aromatic impurities 2204 as described above, to form an effluent stream 2216 without higher acetylene and aromatic impurities. The effluent separator 2202 is in fluid communication with the acetylene separator 2208 (collectively forming block B in the figure) which receives the effluent stream 2216 and removes the purified acetylene product 2210 therefrom as described above. Next, the acetylene separator 2208 is in fluid communication with the hydrogen separator 2212 (collectively forming block C in the figure) for the removal of the purified hydrogen product 2214, and any remaining gas is shown as the remaining gas 2218. As shown, the remaining gas 2218 can be recycled for further use in the plasma-based hydrocarbon treatment system 2206. This arrangement is described above and shown in Figures 20 and 21. As previously described, the purified hydrogen product 2210 and the purified acetylene product 2214 are suitable for use in the vitamin manufacturing system 2220. Other arrangements of the blocks shown are also compatible with the systems and methods disclosed herein. In an embodiment, for example: block A (C + separation) may precede block C (H2 separation), which may precede block B (C2H2 separation); block C (H2 separation) may precede block A (C + separation), which may precede block B (C2H2 separation); or block C (H2 separation) may precede block B (C2H2 separation), which may precede block A (C +Following separation, it is optionally recycled based on the order of the blocks. In embodiments, one or more blocks may be omitted. For example, if pure hydrogen is provided to the system from an external source, hydrogen separation (block C) may be omitted. Or, for example, a vitamin manufacturing system may have lower purity requirements than those provided by these systems and methods, in which case block A (C + separation) may be omitted. In other embodiments, hydrogen may be provided to the vitamin manufacturing system from an external source and a lower purity for acetylene is sufficient for use; in this case, only block B (C2H2 separation) is required.

[0192] c. Acetylene decomposition As another example, acetylene produced by a plasma-based hydrocarbon treatment system can be used as a precursor for an acetylene decomposition process, which yields hydrogen gas and acetylene black. A plasma-based hydrocarbon treatment system as described above can be modified to maximize and optimize the acetylene produced, and the system can be integrated with the processes necessary to convert the acetylene to hydrogen gas and acetylene black. In embodiments, as described above, a plasma-based hydrocarbon treatment system for producing acetylene can deliver this product as a feedstock to an acetylene decomposition subsystem for further processing, so that a fully integrated industrial application integrates the precursor product (i.e., acetylene produced by the plasma-based hydrocarbon treatment system) and precursor utilization to form the desired product, which can be either acetylene black or hydrogen, and simultaneously produces either hydrogen gas or acetylene black (respectively) as useful by-products. Using the systems and methods disclosed herein, acetylene can be produced in situ from natural gas or other hydrocarbon feedstocks used for acetylene decomposition, along with the production of acetylene black and hydrogen. These systems and methods may enable manufacturers to control the efficiency of their logistics and resource use by utilizing an integrated high-purity acetylene source.

[0193] FIG. 23 provides a block diagram showing a general scheme having a series of steps for process 2300 to produce acetylene black and hydrogen using acetylene produced by the plasma-based hydrocarbon treatment system disclosed herein. Note that the scheme shown in FIG. 23 can utilize various plasma-based hydrocarbon treatment systems such as those disclosed herein, acetylene is produced using such a system, and the gas thus produced is then used in whole or in part to produce acetylene black and / or hydrogen.

[0194] Path 2302a shows the process for making acetylene from a feedstock using a plasma-based hydrocarbon processing system as disclosed previously. As an initial step in process 2300, the feedstock is provided 2304 for further processing, where the feedstock includes a hydrocarbon-containing inlet gas and may further include a recycle gas. The feedstock is then processed 2308 using a reactor having a gas delivery subsystem, a plasma reaction chamber, and a microwave subsystem as described previously to an effluent gas product that includes acetylene, hydrogen, and acetylene by-products, and the acetylene, hydrogen, and by-products are discharged from the reactor and enter a set of separators for further separation and purification steps 2310. In an aspect, the process step 2308 includes injecting a hydrocarbon-containing inlet gas into the plasma reaction chamber; energizing the hydrocarbon-containing inlet gas in the plasma reaction chamber with microwave energy to generate a plasma; forming an effluent gas product in the plasma, where the effluent gas product includes acetylene and hydrogen; and flowing the effluent gas product out of the plasma reaction chamber (not shown), where the effluent gas product is processed by a set of separation and purification steps 2310. The separation and purification steps 2310, including steps of exhaust separation, acetylene separation, and hydrogen separation, result in a set of component gases including an acetylene-rich gas stream 2312, and then stream 2312 is distributed 2316 to enter a process for manufacturing acetylene black 2302b. The separation and purification steps also produce off-gases such as acetylene by-products and pure hydrogen that are removed 2314a from the acetylene-rich stream 2312 or are added back 2314b, either in whole or in part, to enter the manufacturing process 2302b, and the acetylene-rich stream 2312 serves as a feedstock for an acetylene decomposition reactor 2318 that produces acetylene black 2330 and hydrogen 2332 from the acetylene in the acetylene-rich stream 2312. Hydrogen, which is part of the off-gas stream 2314a produced by the separation and purification steps, may be recycled (not shown) back to the start of path 2302a as a recycle gas stream that becomes one of the feedstocks 2304 for the plasma-based hydrocarbon processing system, either in whole or in part.In an embodiment, hydrogen from the off-gas stream 2314a can be collected, in whole or in part, directly or indirectly, as a desired final product.

[0195] A separation system using an adsorber as described above is well-suited to create an acetylene-rich stream 2312 that can be routed to a process for manufacturing acetylene black 2302b. As shown in this figure, the separation and purification step 2310 processes the effluent gas product such that an acetylene-rich stream 2312 results that can be separated from the off-gas (either removed from the stream 2314a or re-added to enter the manufacturing process 2302b) and that provides a source for the acetylene decomposition reactor 2318. However, the specific nature of the acetylene-rich stream 2312 can be engineered to meet the requirements of the acetylene decomposition reactor 2318 and associated processes, as generally shown in the process for manufacturing acetylene black 2302b.

[0196] In an embodiment, it may be advantageous to perform a separation and purification step 2310, such as a short cycle TSA with or without the above-described standard TSA, using an acetylene separator (not shown). In such an arrangement, the higher acetylenes captured by the short cycle TSA (e.g., without the standard TSA) may pass through the manufacturing process 2314b, be processed with the acetylene-rich stream 2312, and reach the acetylene cracking reactor 2318. In an embodiment, if, for example, the as-produced acetylene black has favorable properties when not using higher acetylenes, or if the extended regeneration time of a short cycle TSA operated without a TSA washing step introduces a disadvantage, the standard TSA may be operated prior to the short cycle TSA so that a substantially pure acetylene-rich stream 2312 is used. Other acetylene separation methods that provide acetylene with a purity greater than 90%, such as an absorption column system, may also be used. Depending on the quality of the desired acetylene black product, acetylene may be used at a lower purity by providing a stream containing higher acetylenes that is captured by a short cycle TSA without the standard TSA and enters the manufacturing process 2314b either alone or processed with the acetylene-rich stream 2312 and reaches the acetylene cracking reactor 2318.

[0197] Optionally, acceleration species can be added to compensate for either less reactive stream (either stream 2314b alone or stream 2314b mixed with the acetylene-rich stream 2312). Balancing the levels of limiting and acceleration species is important for the production of high-quality acetylene black and hydrogen from impure acetylene streams. Some limiting species such as methane, ethylene, and propadiene are found in impure streams and can decompose endothermically. Other limiting species such as hydrogen and nitrogen may be found in impure streams but do not decompose permanently. However, limiting species reduce the heat from the reaction (sap) and change the properties of the produced acetylene black; in excess, they can cool the process sufficiently to stop the reaction. Therefore, limiting species are avoided in the acetylene-rich stream 2312. Acceleration species in the acetylene mixture tend to add heat to the reaction and also change the properties of the produced acetylene black. When present in excess, they can decompose the gas mixture spontaneously or in response to a little provocation, leading to concerns about safety and reliability. For example, acceleration species such as higher acetylenes release more energy than acetylene when they decompose. Others such as oxidizing agents increase the rate of the reaction. Both limiting and acceleration species can be present in the feed stream 2312 and can be balanced against each other for further control of the properties of the produced acetylene black.

[0198] Via the reaction shown in path 2302a of FIG. 23, the plasma-based hydrocarbon treatment system produces acetylene and hydrogen in a stoichiometric ratio of 1:3 from methane, which is the main component of natural gas. The acetylene decomposition reaction involved in the production of acetylene black 2302b produces 1 mole of hydrogen 2332 for each 1 mole of reacted acetylene, along with the acetylene black itself 2330. Therefore, by converting acetylene produced from methane by the plasma-based hydrocarbon treatment system (as disclosed herein) to hydrogen and acetylene black, the total hydrogen produced is increased by only 1 / 3 up to 4 moles of hydrogen gas per 2 moles of methane. Thus, this system is advantageous for producing hydrogen; in addition to the hydrogen (shown herein as the hydrogen-containing off-gas 2314a removed from the system and the hydrogen-containing off-gas that is added again 2314b together with the acetylene-rich stream 2312 and re-enters the acetylene black production process 2302b) produced by the plasma-based hydrocarbon treatment system, the acetylene decomposition reactor 2318 produces a substantial amount of hydrogen 2332, which can be further purified if any acetylene black is considered a by-product and a second pure hydrogen product is desirable as a by-product or main final product of acetylene decomposition.

[0199] In embodiments, these systems and methods can be readily adapted to produce hydrogen as the desired final product, for example, by separating hydrogen in the separated off-gas 2314a from the acetylene by-product. Systems and methods for producing hydrogen as the desired final product are described in more detail with reference to FIG. 24 below. In embodiments, the hydrogen gas produced by these systems and methods can be recycled to the plasma-based hydrocarbon treatment system further or alternatively, as previously described. Advantageously, in contrast to hydrogen produced by other techniques such as partial oxidation of methane or natural gas, the carbon released from the feedstock in the acetylene decomposition reactor 2318 is sequestered into a second stable useful product, acetylene black 2330, instead of being released as carbon monoxide and ultimately carbon dioxide, which are common by-products of certain conventional processes.

[0200] In an embodiment, a feedstock other than methane can be used to produce acetylene via a plasma-based hydrocarbon processing system as disclosed herein; the ratio of hydrogen to acetylene produced using such a feedstock is less than 3:1, and the relative increase in total hydrogen production is greater than 1 / 3. Further, an acetylene decomposition reactor that produces acetylene black from an acetylene-rich feedstock 2312 permits a non-pure acetylene stream within a specific range, and the exact composition of this stream can affect the properties of the acetylene black product. A purification system that includes one or more adsorption steps as described above enables careful separation of the ideal mixture of products for hydrogen and acetylene black production.

[0201] As described above, the acetylene-rich stream 2312 produced by the separation and purification step 2310 is distributed 2316 to reach the acetylene decomposition reactor 2318. The acetylene-rich stream 2312 can be distributed 2316 for this purpose via direct delivery 2324 (i.e., without gas intermediate routing changes or isolation); additionally or alternatively, the acetylene-rich stream 2312 can be distributed 2316 for storage 2322 or for a commercialization process 2320 such as bottling, and either of these purposes can be utilized to provide feedstock to the acetylene decomposition reactor 2318 (as shown by paths 2326 and 2328). The steps indicated by the paths within 2302b show how the acetylene-rich stream 2312 produced by the plasma-based hydrocarbon processing path 2302a can enter the acetylene decomposition reactor 2318. In an embodiment, acetylene can be bottled 2320, where pure acetylene from the acetylene-rich stream 2312 is stored in bottles made in a commercial standard size by dissolving it in a liquid medium at high pressure; the bottled acetylene 2320 can be used as a feedstock for the acetylene decomposition reactor 2318 or can be commercialized separately.

[0202] The distribution process 2316 is intended to optimize the utilization of acetylene produced by the plasma-based hydrocarbon treatment path 2302a by adjusting the inflow of the acetylene-rich stream 2312 produced by the path 2302a to match that required by the acetylene decomposition reactor 2318, for example, via a feedback mechanism. The inflow of the acetylene-rich stream 2312 is increased or decreased according to the measurement of the required acetylene provided by the acetylene black production system.

[0203] As described above, these systems and methods can be optimized to maximize the amount and purity of hydrogen shown in this figure, formed as the hydrogen product 2332 of the acetylene decomposition reactor 2318 and as pure hydrogen separable from the offgas removed as 2314a. Further details regarding the disposition of hydrogen separable from the offgas removed as 2314a are provided below with reference to FIG. 24.

[0204] FIG. 24 shows in more detail how the systems and methods disclosed herein can be integrated with systems and processes for producing hydrogen as separate commercializable products. This figure shows aspects of the systems disclosed herein that show how these systems and methods produce highly purified acetylene suitable for direct and / or controllable delivery to manufacturing processes such as the production of acetylene black and / or the production of hydrogen gas described above. The systems and methods disclosed herein can optimize the process for producing hydrogen in partnership with the production of carbon-containing products such as acetylene black.

[0205] FIG. 24 shows an embodiment of a hydrogen and acetylene production system 2400 that first produces hydrogen gas and acetylene in a plasma-based hydrocarbon subsystem 2402 that is substantially similar to these previously described plasma-based hydrocarbon subsystems. The hydrogen gas produced by the plasma-based hydrocarbon subsystem 2402 can be recycled or commercialized separately as described below. The acetylene produced by the plasma-based hydrocarbon subsystem 2402 can be commercialized separately or used as a feedstock for a system 2450 that produces acetylene black and additional hydrogen similar to the system described above and shown in FIG. 23.

[0206] Referring to FIG. 24 in more detail, the plasma-based hydrocarbon processing system 2402 produces a highly purified acetylene product 2408 that can be delivered to a system 2450 for producing acetylene black. In the embodiment shown, the plasma-based hydrocarbon processing system 2402 includes a microwave reactor 2414 that includes a plasma reaction chamber (not shown) to which a hydrocarbon inlet stream 2410 (e.g., natural gas) and a recycle gas stream 2412 are delivered, where they are energized by a microwave subsystem (not shown) to form a plasma that produces chemical products exiting the plasma chamber, forming an outlet stream 2418 of the effluent gas product, all of which are described in detail in previous figures. In the embodiment shown, the outlet stream 2418 is subjected to further processing and separation, such as passing through a set of separator subsystems.

[0207] The set of separator subsystems, all of which have been described in more detail previously, in the embodiment shown: (i) produce a purified exhaust stream 2422, higher order acetylene and aromatic impurities (C3, using, for example, a temperature swing adsorber or a prescrubber) +(i) an effluent separator 2420 for removal of ; (ii) an acetylene separator 2424 for separation of highly purified acetylene product 2408 from the purified effluent stream 2422 through an acetylene purification column or the like, whereupon a residual effluent stream 2428 then exits the acetylene separator; and (iii) a hydrogen separator 2430 (e.g., a pressure swing adsorber, a temperature swing adsorber, or a membrane separator). The subsystem can be arranged in the order shown in FIG. 24, where the hydrogen separator 2430 is downstream of the acetylene separator 2424, so that hydrogen is separated as a highly purified hydrogen product from the residual effluent stream 2428 from which the highly purified acetylene product 2408 has already been removed. In other embodiments, the hydrogen separator 2430 can be arranged upstream from the acetylene separator 2424, so that hydrogen is removed from the purified effluent stream 2422 before the purified effluent stream enters the acetylene separator 2424. Any hydrogen removed by the hydrogen separator 2430 (either upstream or downstream from the acetylene separator 2424) can be isolated from the system either as an integrated hydrogen stream for use in integrated manufacturing or chemical processing, or as an external hydrogen stream for another commercialization, storage, or disposal, or can be recycled back into the system as a recycled hydrogen stream, all as described below.

[0208] More specifically, FIG. 24 shows one possible sequence of the separator process and subsystems. In the illustrated embodiment, the residual exhaust stream 2428 is split by a splitter 2426 into two streams, 2428a and 2428b. The first residual exhaust stream portion 2428a undergoes further processing in a hydrogen separator 2430, and a purified hydrogen product 2432 is separated therefrom, resulting in a residual gas stream 2436. The second residual exhaust stream portion 2428b is rerouted by the splitter 2426 before entering the hydrogen separator 2430 and is instead recycled to form a recycle gas stream 2412 (either alone or in combination with other gas streams such as the residual gas stream 2436 discharged from the hydrogen separator 2430 as shown); the recycle gas stream 2412 is available for use in the microwave reactor 2414 as described above. In an embodiment, the splitter 2426 can be a valve or other set of passages that controllably directs the flow of the residual exhaust stream 2428 to one or both of the first residual exhaust stream portion 2428a and the second residual exhaust stream portion 2428b. In an embodiment, the splitter 2426 is an optional feature. The residual gas stream 2436 can be used to form the recycle gas stream 2412 either by being mixed with other recyclable gas streams such as the second residual exhaust stream 2428b (as shown in this figure) and / or combined with other gas streams (not shown), or it can be used alone to form the recycle gas stream 2412.

[0209] The purified hydrogen product 2432 discharged from the hydrogen separator 2430 can be directed to one or more effluent streams 2432a, 2432b, and 2432c. The effluent gas streams 2432a and / or 2432c can be isolated from the overall processing system 2402 and used in other manufacturing processes (not shown) that can be integrated with and / or in fluid communication with the overall system 2402, or separated from the overall system 2402 as another commercial product for further sale, storage, or disposal. More specifically, one of the streams 2432a is an integrated hydrogen stream that is used in other integrated processes (not shown) where hydrogen can be used as a feedstock, such as in a chemical manufacturing process. By way of example, the purified hydrogen product 2432 can be directed to form the integrated hydrogen stream 2432a and combined with the purified acetylene product 2408 in other integrated processes such as those previously described for vitamin manufacturing. In an aspect, the purified hydrogen product 2432 can be isolated as an external hydrogen stream 2432c for further sale, storage, or disposal. As shown for the streams 2432a and 2432c, instead of or in addition to being isolated, the purified hydrogen product 2432 can be directed as a recycled hydrogen stream 2432b and can form a component of the recycled gas stream 2412, for example, by combining with the residual gas stream 2436. It is understood that the purified hydrogen product 2432 can be directed to one or more of the sub-paths 2432a, 2432b, and 2432c according to commercial requirements such as these situations where the system 2402 is integrated with other manufacturing or storage subsystems (not shown). In an aspect, a controller (not shown) directs an appropriate amount of the purified hydrogen product 2432 along one or more preselected sub-paths 2432a, 2432b, and / or 2432c.

[0210] In an embodiment, recycling hydrogen to the processing system 2402 at any point in the system downstream of the microwave reactor can be carried out as an advantageous alternative to recycling in or before the microwave reactor, so that impurities or contaminants in the recycled stream can be removed by the presence of a separation process, and the hydrogen can be further purified by the presence of a purification facility. In other embodiments, the hydrogen can be of sufficient quality such that the hydrogen can be recycled to a microwave reactor that is placed in a primary storage or holding tank and used either immediately or subsequently. As described above, since the hydrogen can be isolated instead of recycled, the hydrogen can be directed to another integrated industrial use 2342a or the hydrogen can be directed off-site 2432c for sale or use, either as a gas or a liquid.

[0211] Regardless of the use of hydrogen as the desired product (as in 2432a or 2432c), the hydrogen can optionally be further purified using a purification process such as a membrane, PSA, etc. (any process known in the art) so as to be suitable for its intended use. In an embodiment, whether or not further purified, the hydrogen can be used directly in a chemical synthesis process, can be used as fuel for a hydrogen fuel cell, can be combusted, etc., as suggested by the subpath 2432c. In an embodiment, all or part of this hydrogen stream indicated for use as an integrated hydrogen stream 2432a or an external hydrogen stream 2432c can be stored (either as a gas or compressed into a liquid), whether or not further purified, or can also be transported or distributed by pipeline or container to another location where the product is used for its intended use.

[0212] As shown in FIG. 24, the acetylene-rich stream 2408 produced by the acetylene separator 2424 is distributed by the controller 2440 for further use in the process 2450 of producing acetylene black and hydrogen. The controller 2440 enables the distribution of the acetylene-rich stream 2408 according to the requirements of the manufacturing system. The acetylene-rich stream 2408 ultimately reaches the acetylene decomposition reactor 2446 that separates acetylene into the component products of acetylene black 2448 and hydrogen 2460. Similar to these systems and methods shown in FIG. 23, the controller 2440 optimizes the use of the highly purified acetylene produced by the plasma-based hydrocarbon treatment path 2402 by adjusting the inflow of the acetylene-rich stream 2408 through the path 2402 to match the requirements of the process 2450 for producing acetylene black and hydrogen, for example, via a feedback mechanism. The inflow of the acetylene-rich stream 2408 is increased or decreased according to the measurement of the required acetylene provided by the acetylene decomposition reactor 2446.

[0213] The acetylene-rich stream 2408 can reach the acetylene decomposition reactor 2446 via direct delivery 2442 (i.e., without intermediate route change or isolation of the gas); additionally or alternatively, the acetylene-rich stream 2408 can be distributed for commercialization processes 2452 such as storage 2456 or bottling. Any of these purposes can be utilized to provide the acetylene-rich feedstock for use in the acetylene decomposition reactor 2446.

[0214] Similar to the system shown in FIG. 23, the integrated hydrogen and acetylene production system shown in FIG. 24 is advantageous for producing hydrogen. In addition to the hydrogen 2432 produced by the plasma-based hydrocarbon treatment system, the acetylene decomposition reactor 2446 produces a substantial amount of hydrogen 2460, which can be further purified if a second pure hydrogen product is desired as a byproduct of acetylene decomposition or as a major final product, and any acetylene black is considered a byproduct.

[0215] In some embodiments, these systems and methods can be readily adapted to produce hydrogen as the desired end product. For example, the hydrogen 2432 produced by the plasma-based hydrocarbon processing system can be combined with the hydrogen 2460 produced by the acetylene cracking reactor 2446 for any of the previously described hydrogen uses. For example, the hydrogen 2432 and 2460 produced from both sources can provide feedstock to another integrated chemical processing plant (not shown). As another example, the hydrogen 2432 and 2460 produced from both sources can be bottled or otherwise transported to the end user, or distributed to a backbone facility that supplies a filling station equipped with hydrogen, such as that which can be used by a hydrogen-powered vehicle. Other direct uses for the hydrogen 2432 and 2460 produced by these systems and methods can be readily envisioned by those skilled in the art, and such uses will expand as the hydrogen economy gains a greater presence in the market. In other embodiments, the hydrogen gas produced by these systems and methods can be recycled further or alternatively to the plasma-based hydrocarbon processing system as previously described. Advantageously, in contrast to hydrogen produced by other techniques such as partial oxidation of methane or natural gas, the carbon released from the feedstock in the acetylene cracking reactor 2446 (i.e., acetylene black 2448) is diverted to a second stable useful article, acetylene black 2448, instead of being released as carbon monoxide and ultimately carbon dioxide, both of which are common by-products of certain conventional processes.

Example

[0216] Example Example 1 A flow of precursor gas composed of 99.9% purity methane at 60 standard liters per minute, 99.9% purity hydrogen at 90 standard liters per minute, and nitrogen at 6 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 50 mm and an inner diameter of 45 mm maintained at a pressure of 70 torr. The precursor gas was subjected to 19 kW of incident 915 MHz microwave power in a plasma reactor device similar to that described in FIG. 3. 95.7% of the methane contained in the precursor gas was converted to hydrogen and hydrocarbon products. The hydrocarbon composition of the effluent gas exiting the reactor as analyzed by gas chromatography is described in Table 6 below.

Table 6

[0217] The effluent gas from the reactor was passed through a gas cooling and heating sink, then through a corrugated paper filter, and then discharged from a vacuum pump. The effluent gas was then passed through a cold trap operating at 10°C and a further filter.

[0218] A portion of the effluent gas was then passed through an adsorption column containing high surface area activated carbon. The composition of the effluent gas at the adsorption column outlet is shown in Table 7 below.

Table 7

[0219] After exiting the adsorption column, a portion of the effluent gas was then passed through the adsorption column. The solvent, N-methylpyrrolidone, was flowed countercurrently to the effluent gas to preferentially absorb acetylene. The solvent with acetylene absorbed was pumped to a second column for solvent recovery and heated to 120 - 140°C. In the second column, acetylene and related gases were removed from the solvent as a purified product gas stream, and the recovered solvent was recycled to the system. Table 8 below shows the composition of the purified product gas stream exiting the second column.

Table 8

[0220] Example 2 The flow of the precursor gas composed of 99.9% purity methane at 20 standard liters per minute, ethane at 20 standard liters per minute, 99.9% purity hydrogen at 95 standard liters per minute, and nitrogen at 6 standard liters per minute was supplied through the plasma reactor device described in Example 1 and reacted with an incident 915 MHz microwave power of 18 kW using the plasma reactor device used in Example 1. 97.9% of the methane and ethane contained in the supplied gas was converted into hydrogen and hydrocarbon products. The hydrocarbon composition of the effluent gas from the reactor when analyzed by gas chromatography is described in Table 9 below.

Table 9

[0221] Example 3 The flow of the precursor gas composed of 99.9% purity methane at 110 standard liters per minute and nitrogen at 11 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 80 mm and an inner diameter of 75 mm. The precursor gas was subjected to an incident 915 MHz microwave power of 11 kW in a plasma reactor device as described in FIG. 3. 50.7% of the methane contained in the precursor gas was converted into hydrogen and hydrocarbon products. 7% of the converted methane produced carbon solids and polycyclic aromatic hydrocarbons. 76% of the converted methane produced acetylene.

[0222] Example 4 A flow of precursor gas composed of 99.9% purity methane at 100 standard liters per minute, 99.9% purity hydrogen at 160 standard liters per minute, and nitrogen at 10 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 50 mm and an inner diameter of 45 mm maintained at 70 torr. The precursor gas was subjected to an incident 915 MHz microwave power of 29 kW in a plasma reactor device similar to that described in FIG. 3. 90.3% of the methane contained in the precursor gas was converted to hydrogen and hydrocarbon products. The hydrocarbon composition of the effluent gas exiting the reactor is described in Table 10 below. [Table 10]

[0223] Example 5 A flow of precursor gas composed of 99.9% purity methane at 130 standard liters per minute and nitrogen at 13 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 80 mm and an inner diameter of 75 mm maintained at 48 torr. The precursor gas was subjected to an incident 915 MHz microwave power of 24.3 kW in a plasma reactor device similar to that described in FIG. 3. 85.2% of the methane contained in the precursor gas was converted to hydrogen and hydrocarbon products.

[0224] Example 6 A flow of precursor gas composed of 99.9% purity methane at 74 standard liters per minute, 99.9% purity hydrogen at 40 standard liters per minute, and nitrogen at 88 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to an 80 mm outer diameter, 75 mm inner diameter quartz tube maintained at 70 torr. The precursor gas was subjected to an incident 915 MHz microwave power of 23.9 kW in a plasma reactor device similar to that described in FIG. 3. 95.1% of the methane contained in the precursor gas was converted to hydrogen and hydrocarbon products.

[0225] Example 7 The flow of a precursor gas composed of 99.9% purity methane at 47 standard liters per minute, 99.9% purity hydrogen at 110 standard liters per minute, and nitrogen at 5 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 80 mm and an inner diameter of 75 mm maintained at 65 Torr. The precursor gas was subjected to 15.6 kW of incident 915 MHz microwave power in a plasma reactor device similar to that described in FIG. 3. 89.7% of the methane contained in the precursor gas was converted to hydrogen and hydrocarbon products.

[0226] Example 8 The flow of a precursor gas composed of 99.9% purity methane at 90 standard liters per minute, 99.9% purity hydrogen at 135 standard liters per minute, and nitrogen at 9 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 38 mm and an inner diameter of 35 mm maintained at 105 Torr. The precursor gas was subjected to 25 kW of incident 915 MHz microwave power in a plasma reactor device similar to that described in FIG. 3. 92.0% of the methane contained in the precursor gas was converted to hydrogen and hydrocarbon products.

[0227] Example 9 The flow of a precursor gas composed of 99.9% purity butane at 15 standard liters per minute, 99.9% purity hydrogen at 90 standard liters per minute, and nitrogen at 6 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a quartz tube with an outer diameter of 50 mm and an inner diameter of 45 mm maintained at 50 Torr. The precursor gas was subjected to 17.7 kW of incident 915 MHz microwave power in a plasma reactor device similar to that described in FIG. 3. 100% of the butane contained in the precursor gas was converted to hydrogen and hydrocarbon products, having a methane yield of 0.6%.

[0228] Example 10 The flow of a precursor gas composed of 99.9% purity ethane at 30 standard liters per minute, 99.9% purity hydrogen at 90 standard liters per minute, and nitrogen at 6 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a 50 mm outer diameter, 45 mm inner diameter quartz tube maintained at 126 torr. The precursor gas was subjected to 16 kW of incident 915 MHz microwave power in a plasma reactor device similar to that described in FIG. 3. 100% of the ethane contained in the precursor gas was converted to hydrogen and hydrocarbon products, having a methane yield of 3.3%. The hydrocarbon composition of the effluent gas exiting the reactor is described in Table 11 below. [Table 11]

[0229] Example 11 The flow of a precursor gas composed of 99.9% purity propane at 8.6 standard liters per minute, 99.9% purity butane at 8.6 standard liters per minute, 99.9% purity hydrogen at 88 standard liters per minute, and nitrogen at 6 standard liters per minute was supplied through a gas injector device similar to that described in FIGS. 4A and 4B to a 50 mm outer diameter, 45 mm inner diameter quartz tube maintained at 70 torr. The precursor gas was subjected to 16 kW of incident 915 MHz microwave power in a plasma reactor device similar to that described in FIG. 3. 100% of the ethane contained in the precursor gas was converted to hydrogen and hydrocarbon products, having a methane yield of 3.2%. The hydrocarbon composition of the effluent gas exiting the reactor is described in Table 12 below. [Table 12]

[0230] Example 12 A plasma reactor system as described in Example 1 that produces 250 liters of effluent gas per minute was used. After the vacuum pump in the system, solid carbon by-products were removed by a simple in-line filter. Liquid hydrocarbon concentrates containing more than 14 carbon atoms were separated from the stream in a cold trap operating at -20 °C. Further hydrocarbons were not removed, and the effluent was passed directly through an 8-inch inner diameter stainless steel container containing 0.4 kg of blank 100-200 mesh α-alumina mixed with 1.8 kg of 100-200 mesh α-alumina doped with 3 wt% metallic palladium and 4 wt% metallic silver. The catalyst bed was maintained at 350 °C by an internal open-loop water cooling system. A gas mixture containing 50% hydrogen, 11% ethylene, 0.5% ethane, and 38.5% methane was obtained; the acetylene content in the gas mixture was deliberately maintained below 100 ppm.

[0231] Example 13 A plasma reactor system as described in Example 1 was used. A flow of 1 liter of effluent gas per minute was separated and further processed as described in this example. After the vacuum pump, solid carbon by-products were removed with a ceramic regenerable filter. Liquid hydrocarbon concentrates containing more than 10 carbon atoms were separated from the stream in a cold trap operating at -30 °C. Thereafter, the effluent gas was passed through a stainless steel container containing 20 grams of high surface area activated carbon doped with 0.01% metallic palladium. The effluent gas at this point contained 85% hydrogen, 8% acetylene, 4% ethylene, and 0.6% vinyl acetylene and the balance methane. Vinyl acetylene was removed by bubbling through a 500 mL container containing 300 mL of concentrated sulfuric acid at room temperature and then through a container containing 100 mL of room temperature water, trapping the volatilized sulfuric acid. Finally, the gas stream was dried by passing it through 10 grams of calcium sulfate desiccant.

[0232] Example 14 A precursor gas composed of 303 standard liters per minute of useful natural gas (having a composition of approximately 96.7% methane, approximately 2.7% ethane, and approximately 0.4% nitrogen), 628 standard liters per minute of 99.9% purity hydrogen, and 31 standard liters per minute of nitrogen was supplied through a gas injector device similar to that described in FIGS. 4a and 4b to a quartz tube with an outer diameter of 50 mm and an inner diameter of 45 mm maintained at 260 mbar. The precursor gas was subjected to 98 kW of incident 915 MHz microwave power in a plasma reactor device as described in FIG. 3. 90.6% of the hydrocarbons contained in the precursor gas were converted to hydrogen and hydrocarbon products. The reactor effluent gas composition excluding nitrogen as analyzed by gas chromatography is described in Table 13.

Table 13

[0233] The effluent gas from the reactor was passed through a gas cooling and heating sink, then through a corrugated paper filter, and then discharged from a vacuum pump. The effluent gas was then passed through a cold trap operating at 10°C and a further filter.

[0234] Equivalents Although the present invention has been specifically shown and described with reference to its preferred embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the scope of the invention as included in the appended claims. Unless otherwise indicated, all numbers expressing reaction conditions, quantities, amounts, ranges, etc. are to be understood as being modified in all instances by the term "about" when used in this specification and the appended claims. Accordingly, unless otherwise indicated, the numerical parameters set forth herein are approximate values that may vary depending upon the desired properties sought to be obtained by the present invention.

[0235] Furthermore, the present invention encompasses all variations, combinations, and permutations in which one or more limitations, elements, terms, and descriptive terms from one or more of the recited claims are introduced into another claim. For example, any claim that depends on another claim can be modified to include one or more limitations found in any other claim that depends on the same base claim. If elements are presented as a list, for example in the form of a Markush group, each subgroup of the elements is also disclosed, and any element(s) can be removed from the group. Generally, when the invention or an aspect of the invention is referred to as including a particular element and / or feature, it should be understood that a particular embodiment of the invention or aspect of the invention consists of or consists essentially of such element and / or feature. For the sake of simplicity, these embodiments are not specifically described herein in haec verba. Note also that the terms "comprising" and "containing" are intended to be open and to allow the inclusion of further elements or steps. When a range is given, the endpoints are included. Further, unless it is indicated otherwise or is apparent from the context and the understanding of the person skilled in the art that it is not the case, values expressed as ranges may assume any specific value or sub-range within the ranges recited in different embodiments of the invention down to one tenth of the unit of the lower limit of the range, unless the context clearly indicates otherwise. Examples of aspects of the present invention include the following. Item 1 A system for converting a hydrocarbon-containing influent gas into an effluent gas product, comprising a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and an emissions separation and disposal system; The gas delivery subsystem: i. Is in fluid communication with the plasma reaction chamber and directs one or more gases into the plasma reaction chamber, where the one or more gases include a hydrocarbon-containing influent gas; ii. Includes a delivery conduit and a gas injector, a. The delivery conduit is in fluid communication with the gas injector, the delivery conduit includes a supply gas transport circuit that delivers one or more gases to the gas injector, and the delivery conduit delivers a hydrocarbon-containing influent gas into the gas injector, b. The gas injector delivers one or more gases into the plasma reaction chamber; The plasma reaction chamber: i. Is in fluid communication with the emissions separation and disposal system; ii. Is disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem; The microwave subsystem: i. Directs microwave energy into the plasma reaction chamber to supply energy to the hydrocarbon-containing influent gas, thereby forming a plasma in the plasma reaction chamber, where the plasma converts the hydrocarbons in the hydrocarbon-containing influent gas into an effluent gas product, and the effluent gas product includes acetylene and hydrogen; ii. Includes an applicator for directing microwave energy into the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of the elongated reactor tube that passes through the applicator and intersects the applicator perpendicularly; and iii. Further includes a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is transported by the waveguide to the applicator, and the applicator directs the microwave energy into the reaction chamber within the elongated reactor tube, thereby forming a plasma in the plasma reaction chamber. Here, the effluent gas product flows through the plasma reaction chamber to the distal end of the elongated reactor tube, exits from the distal end of the elongated reactor tube, and forms an exhaust stream that enters the effluent separation and disposal subsystem. The effluent separation and disposal system includes a short-cycle temperature swing adsorption system adapted to separate hydrogen from the exhaust stream. System. Item 2 A system for converting a hydrocarbon-containing inlet gas to a VCM (vinyl chloride monomer)-containing liquid product, including a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and a VCM reactor and separator subsystem. The gas delivery subsystem includes: i. In fluid communication with the plasma reaction chamber to direct one or more gases into the plasma reaction chamber, where the one or more gases include the hydrocarbon-containing inlet gas. ii. Includes a delivery conduit and a gas injector. a. The delivery conduit is in fluid communication with the gas injector. The delivery conduit includes a supply gas transport circuit that delivers one or more gases to the gas injector and delivers the hydrocarbon-containing inlet gas into the gas injector. b. The gas injector delivers one or more gases into the plasma reaction chamber. The plasma reaction chamber includes: i. In fluid communication with the effluent separation and disposal system. ii. Is disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem. The microwave subsystem includes: i. Directs microwave energy into the plasma reaction chamber to supply energy to the hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber. Here, the plasma converts the hydrocarbons in the hydrocarbon-containing inlet gas to an effluent gas product, and the effluent gas product includes acetylene and hydrogen. ii. Includes an applicator for directing microwave energy into the plasma reaction chamber, where the plasma reaction chamber passes through the applicator and is disposed in a region of the elongated reactor tube that intersects the applicator perpendicularly; and iii. Further including a power source, a magnetron, and a waveguide, wherein the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is conveyed by the waveguide to the applicator, and the applicator directs the microwave energy to a reaction chamber within an elongated reactor tube, thereby forming a plasma in the plasma reaction chamber. Here, the effluent gas product flows through the plasma reaction chamber to the distal end of the elongated reactor tube, exits from the distal end of the elongated reactor tube, forming an effluent stream that enters the VCM reactor and the separator subsystem, and the VCM reactor and the separator subsystem include a VCM reactor and a plurality of separators; i. Here, the plurality of separators includes a first separation system, a second separation system, and a third separation system; ii. The first separation system is a discharge separator in fluid communication with the elongated reactor tube and adapted to remove higher acetylenes and aromatics from the effluent stream, producing a purified effluent stream for delivery to the VCM reactor, and the purified effluent stream contains acetylene gas; and here: (a) The VCM reactor is in fluid communication with the first separation system and the second separation system; (b) The VCM reactor rec...

Claims

1. A step of providing one or more gases, wherein the one or more gases include a hydrocarbon-containing inlet gas, and the hydrocarbon-containing inlet gas includes methane; and A step of directing the one or more gases into the system A method for converting a hydrocarbon-containing inlet gas into an outlet gas product, comprising: the system includes a gas delivery subsystem, a plasma reaction chamber, a microwave subsystem, and an exhaust gas separation and disposal subsystem; The gas delivery subsystem includes: i. being in fluid communication with the plasma reaction chamber and directing the one or more gases into the plasma reaction chamber, where the one or more gases include a hydrocarbon-containing inlet gas; ii. including a delivery conduit and a gas injector, a. the delivery conduit is in fluid communication with the gas injector, the delivery conduit delivers the one or more gases to the gas injector, and the delivery conduit includes a supply gas transport circuit for delivering the hydrocarbon-containing inlet gas into the gas injector, b. the gas injector delivers the one or more gases into the plasma reaction chamber; The plasma reaction chamber includes: i. being in fluid communication with the exhaust gas separation and disposal subsystem; ii. being disposed within an elongated reactor tube having proximal and distal ends, where the elongated reactor tube is dimensionally adapted for interaction with the microwave subsystem; The microwave subsystem includes: i. directing microwave energy into the plasma reaction chamber to supply energy to the hydrocarbon-containing inlet gas, thereby forming a plasma in the plasma reaction chamber, where the plasma converts the hydrocarbons in the hydrocarbon-containing inlet gas into an outlet gas product, and the outlet gas product includes acetylene and hydrogen; ii. including an applicator for directing microwave energy into the plasma reaction chamber, where the plasma reaction chamber is disposed in a region of the elongated reactor tube that passes through the applicator and intersects the applicator perpendicularly; and iii. further including a power source, a magnetron, and a waveguide, where the power source supplies energy to the magnetron to generate microwave energy, the microwave energy is transported to the applicator by the waveguide, and the applicator directs the microwave energy into the reaction chamber within the elongated reactor tube, thereby forming a plasma in the plasma reaction chamber ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ Here, the effluent gas product flows through the plasma reaction chamber to the distal end of the elongated reactor tube, exits from the distal end of the elongated reactor tube, and forms an exhaust stream that enters the effluent separation and disposal subsystem. The effluent separation and disposal subsystem includes a hydrogen separation subsystem that removes hydrogen from the exhaust stream. The system further includes a vacuum subsystem that creates a first reduced pressure environment for the effluent gas product passing through one or more components of the effluent separation and disposal subsystem. The first reduced pressure environment has a pressure of 120 to 280 torr. **Claim 2** The method according to claim 1, wherein the hydrocarbon-containing inlet gas includes a gas selected from the group consisting of methane, ethane, propane, and butane. **Claim 3** The method according to claim 2, wherein the hydrocarbon-containing inlet gas consists of methane. **Claim 4** The method according to claim 2, wherein the hydrocarbon-containing inlet gas includes methane. **Claim 5** The method according to claim 1, wherein the delivery conduit includes a further gas transport circuit that delivers a further gas to the gas injector. **Claim 6** The method according to claim 5, wherein the further gas is hydrogen. **Claim 7** The method according to claim 5, wherein the further gas transport circuit is an auxiliary gas transport circuit that delivers an auxiliary gas to the gas injector. **Claim 8** The method according to claim 5, wherein the further transport circuit is a recirculation gas transport circuit that delivers a recirculation gas to the gas injector. **Claim 9** The method according to claim 8, wherein the recirculation gas includes hydrogen. **Claim 10** The method according to claim 8, wherein the recirculation gas consists of hydrogen. **Claim 11** The method according to claim 1, wherein the delivery conduit delivers each of one or more gases to the gas injector through a separate path. **Claim 12** The method according to claim 1, wherein the gas injector includes an injector body portion including two or more coaxially arranged separate gas feeds, a first gas feed that transports the hydrocarbon-containing inlet gas to the plasma reaction chamber through one or more nozzles of a first set, and a second gas feed that transports a further gas to the plasma reaction chamber through one or more nozzles of a second set. **Claim 13** The method according to claim 12, wherein at least one of the one or more nozzles is directed at an angle with respect to the longitudinal axis of the plasma reaction chamber or at an angle with respect to the transverse axis of the plasma reaction chamber. **Claim 14** The method according to claim 12, wherein at least one of the one or more nozzles is directed at an angle with respect to the longitudinal axis or the transverse axis of the injector body portion. **Claim 15** The method according to claim 12, wherein the combined gas flow from the first set of nozzles and the second set of nozzles creates a vortex flow within the plasma reaction chamber.

16. The method according to claim 1, wherein the elongated reactor tube is a quartz tube.

17. The method according to claim 1, wherein the plasma reaction chamber is disposed substantially in the middle of the elongated reactor tube.

18. The method according to claim 5, wherein the gas injector transports a hydrocarbon-containing inlet gas and a further gas to the proximal portion of the elongated reactor tube, and the hydrocarbon-containing inlet gas and the further gas flow distally therefrom to the plasma reaction chamber.

19. The method according to claim 18, wherein the gas injector is disposed at the center of the proximal portion, and one or more nozzles of the first set and one or more nozzles of the second set are directed towards the periphery.

20. The method according to claim 18, wherein the gas injector is disposed at the periphery of the proximal portion, and one or more nozzles of the first set and one or more nozzles of the second set are directed towards the center.

21. The method according to claim 1, wherein the applicator is a one-arm applicator.

22. The method according to claim 1, wherein the magnetron generates L-band microwave energy.

23. The method according to claim 1, wherein the effluent separation and disposal subsystem further includes a solid filter and a cold trap.

24. The method according to claim 1, wherein the effluent separation and disposal subsystem further includes an absorption column.

25. The method according to claim 24, wherein the absorption column absorbs acetylene.

26. The method according to claim 1, wherein the effluent separation and disposal subsystem further includes a concentrated acid in an amount sufficient to oxidize higher hydrocarbons.

27. The method according to claim 1, wherein the effluent separation and disposal subsystem further includes a catalyst suitable for converting higher hydrocarbons into derivative compounds separable from the effluent stream.

28. The method according to claim 1, wherein the effluent separation and disposal subsystem further includes a condenser.

29. The method according to claim 1, wherein the effluent separation and disposal subsystem further includes a gas separation membrane array.

30. The method according to claim 1, wherein the hydrogen separation subsystem is in fluid communication with a recirculation gas transport circuit, and the hydrogen collected by the hydrogen separation subsystem is recirculated to the recirculation gas transport circuit.

31. The method according to claim 1, wherein the effluent separation and disposal subsystem further comprises an acetylene separation subsystem.

32. The method according to claim 1, further comprising a vacuum subsystem that creates a first reduced pressure environment for the effluent gas product passing through one or more components of the effluent separation and disposal subsystem.

33. The method according to claim 32, wherein the vacuum subsystem creates a second reduced pressure environment within an elongated reactor tube.

34. The method according to claim 33, wherein the vacuum subsystem creates a third reduced pressure environment for the gas delivery subsystem.

35. The method according to claim 33, wherein the vacuum subsystem creates the first, second, and third reduced pressure environments.

36. The method according to claim 35, wherein the first reduced pressure environment has a pressure that is at least 10% higher than the pressure in the second reduced pressure environment and / or the third reduced pressure environment.

37. The method according to claim 35, wherein the pressures in the second reduced pressure environment and the third reduced pressure environment are each independently 120 to 280 torr.

38. The method according to any one of claims 1 to 37, wherein the influent gas contains methane and hydrogen in a volume ratio of 1:1 to 3.

39. The method according to any one of claims 1 to 38, wherein the plasma is a non-thermal plasma.

40. The method according to claim 1, wherein the additional gas is a hydrogen-rich reactant gas.

41. The hydrocarbon-containing influent gas contains methane, the plasma is a non-thermal plasma, the delivery conduit includes an additional gas transport circuit for delivering an additional gas to a gas injector, the gas injector includes an injector body portion including two or more coaxially arranged separate gas feeds, a first gas feed for transporting the hydrocarbon-containing influent gas through one or more nozzles of a first set to a plasma reaction chamber, and a second gas feed for transporting the additional gas through one or more nozzles of a second set to the plasma reaction chamber, the effluent separation and disposal subsystem comprises: (a) an acetylene separation subsystem; (b) an absorption column; and (c) a temperature swing adsorption system adapted to remove higher acetylenes from the effluent stream and further includes at least one of the method according to claim 1.

42. The effluent separation and disposal subsystem (a) a filter for removing carbon solids upstream of the acetylene separation subsystem; or (b) a cold trap for removing higher hydrocarbons as a concentrate and further includes the method according to claim 1.

43. The method according to claim 1, wherein the hydrogen separation subsystem is downstream of the acetylene separation subsystem and is in fluid communication with the acetylene separation subsystem.

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