Oxygen-using Chemical Looping for Carbon Production

Abstract

A process for reacting hydrocarbons comprises reacting the hydrocarbons with oxygen in a reactor to produce a gas stream and a solid stream, and separating a gas stream from the solid stream. The gas stream comprises hydrogen, water, and carbon oxides, and the solid stream comprises solid carbon.

Description

Technical Field

[0001] Cross - Reference to Related Applications This application claims priority to 1) U.S. Provisional Patent Application No. 63 / 359,858, entitled "CARBON FORMATION CHEMICAL LOOPING USING OXYGEN", filed on July 10, 2022; 2) U.S. Provisional Patent Application No. 63 / 374,844, entitled "CARBON FORMATION CHEMICAL LOOPING USING OXYGEN", filed on September 7, 2022; and 3) U.S. Provisional Patent Application No. 63 / 387,249, entitled "CARBON FORMATION CHEMICAL LOOPING USING OXYGEN", filed on December 13, 2022, and all of these U.S. provisional patent applications are hereby incorporated by reference in their entirety.

[0002] Statement Regarding Federally Sponsored Research or Development None.

Background Art

[0003] Industrial hydrogen can be mainly produced by reacting hydrocarbon feedstocks (such as CH4, naphtha, biomass, coal, etc.) with oxygen - containing species (such as O2, H2O, CO2) to produce a desired mixture of H2, CO2, and H2O. Overall, the carbon input to the system exits as CO2, and the CO2 is typically either released to the environment or, in future scenarios, geologically sequestered. This results in significant additional costs, carbon taxes, or negative secondary impacts on society (such as climate change) as a result of the costs of the CO2 treatment and sequestration processes.

Summary of the Invention

[0004] In some embodiments, a process for reacting hydrocarbons includes reacting the hydrocarbons with oxygen in a reactor to produce a gas stream and a solid stream, and separating a gas stream from the solid stream. The gas stream includes hydrogen, water, and carbon oxides, and the solid stream includes solid carbon.

[0005] In some embodiments, a process for reacting hydrocarbons includes reacting the hydrocarbons with one or more oxygen-containing species in a first reactor to produce a first product stream that includes hydrogen, water, and carbon oxides, separating water from the first product stream, reacting hydrogen and carbon oxides in a second reactor to produce a second product stream that includes solid carbon, water, hydrogen, and carbon oxides, separating solid carbon from hydrogen, water, and carbon oxides, and separating water from hydrogen and carbon oxides.

[0006] In some embodiments, a reaction process for producing hydrogen and carbon includes introducing a feed stream containing hydrocarbons and an oxidant into a reactor system, producing H2 and solid carbon as products in the reactor system, separating solid carbon and H2 from one or more reactors, and recycling at least a portion of any unreacted hydrocarbons and oxidant to the inlet of the reactor system. The reactor system can include one or more reactors.

[0007] In some embodiments, a system for producing hydrogen and carbon includes one or more reactors, a feed stream containing hydrocarbons, an oxidant, a solid carbon product, and a hydrogen gas product. The reactor is configured to receive the feed stream and the oxidant and to react hydrogen and the oxidant to produce the solid carbon product and the hydrogen gas product. Hydrogen and the oxidant are reacted to produce the solid carbon product and the hydrogen gas product.

[0008] In some embodiments, a process for reacting carbon monoxide and hydrogen comprises reacting a feed stream in contact with a solid phase comprising a catalyst and carbon in a reactor to produce a product stream comprising hydrogen, carbon monoxide, carbon dioxide, water, and solid carbon; separating a solid stream comprising the catalyst and carbon from the product stream to produce a gas stream comprising hydrogen, carbon monoxide, carbon dioxide, and water; cooling the gas stream in a heat exchanger; and separating water from the gas stream after cooling to produce a dehydrated stream comprising hydrogen, carbon monoxide, and carbon dioxide. The feed stream comprises carbon monoxide and hydrogen.

[0009] In some embodiments, a heterogeneous reaction process comprises reacting a feed stream comprising hydrogen and carbon monoxide to produce a gas stream comprising hydrogen, carbon monoxide, and carbon dioxide, and producing a solid phase comprising carbon on a catalyst. The reacting step is performed in the presence of a catalyst in a reactor.

[0010] For a more complete understanding of the present disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description.

Brief Description of the Drawings

[0011]

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DETAILED DESCRIPTION OF THE INVENTION

[0012] DETAILED DESCRIPTION To address the challenges associated with hydrogen production and the simultaneous production of carbon dioxide, various forms of hydrocarbon reactions can be carried out to shift the carbonaceous product to solid carbon. This can be achieved via several different reaction pathways, including: CH4⇔C + 2H2 ΔH o = 76 kJ / mol CH4 (thermal decomposition) 2CO⇔C + CO2 ΔH o = -86 kJ / mol CO (Boudouard reaction) CO + H2⇔C + H2O ΔH o = -175 kJ / mol CO (reduction of CO)

[0013] When C, H, and O are present, it should be understood that other reactions, including water gas shift (WGS), reverse water gas shift (rWGS), methanation, and hydrocarbon reforming, occur to shift the composition towards thermodynamic equilibrium. Carbon formation reactions tend to be either strongly endothermic or strongly exothermic and require continuous addition or removal of heat from the reactor. This can be problematic because the solid surface has a tendency to accumulate carbon when the carbon formation reaction occurs. Additionally, large heats of reaction can reduce the overall thermal efficiency of the process by requiring large heat flows between streams. It is advantageous to make the net reaction in the carbon formation reactor autothermal or exothermic to eliminate the need for heat addition / removal and increase the thermal efficiency. Linking of the carbon formation reaction and / or linking of the carbon formation reaction with other complementary reactions (e.g., reforming, WGS) can be used to achieve this goal.

[0014] In the shift of carbonaceous products to solid carbon, CO2 can be used as a feedstock to make the process CO2 negative at the expense of reducing or eliminating H2 output. This can be advantageous for processes that produce CO2 but have no low-cost means of utilization or sequestration. Considering that CO2 is lower in energy than C, this process requires a significant energy input. Reacting other high-energy species (e.g., CH4) with CO2 to make the net reaction autothermal or exothermic may potentially enable low-cost CO2 sequestration as solid carbon.

[0015] As disclosed herein, a system that uses hydrocarbons (e.g., light alkanes such as CH4, naphtha, biomass, ethanol, vegetable oil, crude oil, etc.), O2, and CO2 as feedstocks and produces primarily C, H2O, and H2 can be designed to utilize a carbon formation reactor that operates autothermally, substantially autothermally, or exothermally. In some embodiments, this process can be referred to as oxidative pyrolysis, and when methane is used as a feedstock, this process can be referred to as methane oxidative pyrolysis. As used herein, the terms substantially autothermal or substantially autothermally refer to the net reaction occurring in the reactor having a heat of reaction of -50 kJ to 50 kJ per mole of carbon contained in the reactant species. This can be done in a single reactor or a series of reactors. When a series of reactors is used, the hydrocarbons and / or CO2 can first be reacted to produce primarily CO as a carbonaceous species that is fed into the carbon formation reactor together with primarily hydrocarbons (e.g., CH4, naphtha, biomass, ethanol, vegetable oil, crude oil, etc.), oxygen, carbon dioxide, and any recycle gas. This can be achieved by one of several means including hydrocarbon reforming (steam reforming, dry reforming, autothermal reforming, biomass / coal gasification, or any combination thereof), reverse water gas shift (rWGS), or CO2 electrolysis. If the CO production reactor is endothermic, an energy input source that is carbon-free (e.g., H2 combustion, electricity) is desirable. Inside the carbon formation reactor, the overall heat of reaction can be modulated near zero (e.g., autothermally) by performing other complementary reactions. This process can be efficient and can enable chemical heating that avoids complexities associated with high-temperature heat transfer mechanisms (e.g., molten heat transfer and reaction media).

[0016] In some embodiments, hydrocarbons and / or CO2 can first be reacted with O2 or H2O to primarily produce H2, CO, and H2O. This can be achieved by one of several means including hydrocarbon reforming (steam reforming, dry reforming, autothermal reforming, biomass / coal gasification, or any combination thereof), reverse water gas shift (rWGS), or CO2 electrolysis. H2O is separated, and the remaining gases are fed into the carbon production reactor together with the recycle gas. When the H2 and CO production reactors are endothermic, an energy input source that is carbon-free (e.g., H2 combustion, electricity) is desirable. Inside the carbon production reactor, the overall heat of reaction can be exothermic due to the predominance of the Boudouard and CO reduction reactions. It should be understood that the heat of reaction can be autothermal if significant methanation and reverse water gas shift reactions occur. In the process, a form of oxygen can be used to promote the production of H2O and to add heat to the reaction. The oxygen can exist in the form of elemental oxygen (O2) and / or carbon monoxide (CO). When CO is used, the CO can be directly converted to solid carbon, for example, using the Boudouard reaction or the CO reduction reaction. The CO can be generated or regenerated as needed using dry reforming of methane (DRM), the water gas shift (WGS) reaction, and the CO / CO2 shift reaction. In some embodiments, the oxygen can be introduced into the system as a seed and removed as an oxygen-containing species, for example, water (e.g., as steam or liquid water) and / or carbon dioxide (CO2) at one or more locations. Water can be selected as a target species for the removal of oxygen in some embodiments to avoid CO2 emissions from the system.

[0017]

[0018] ​In some embodiments, the process can recycle hydrocarbons, CO, and CO2 to prevent their release. Recycling of CO2 is thermodynamically more expensive than hydrocarbons, H2, or CO. The carbon formation reactor can operate with a high H2 to CO ratio and with some CO2 in the feed to suppress the Boudouard reaction and promote the reduction of CO, thereby reducing the production of more CO2 that needs to be recycled. Alternatively, a reverse water gas shift reactor can be placed downstream of the carbon formation reactor to shift CO2 and H2 to CO and H2O.

[0019] System 100 for autothermal C, H2, and H2O production from a feed containing hydrocarbons, O2, and CO2 is shown in FIG. 1. As shown, system 100 contains a single carbon production reactor 110 that receives feeds from a hydrocarbon-containing stream 106, an oxygen-containing stream 102, and a CO2-containing stream 104. The hydrocarbons can include any of those described herein, including light alkanes such as methane, ethane, natural gas, as well as other gaseous, liquid, and solid hydrocarbons (such as ethanol, crude oil, biomass, naphtha, etc.). In some embodiments, a gasification reactor can be used to convert one or more hydrocarbon-containing species into a gaseous stream. In some embodiments, the hydrocarbons can be provided as a fluidized solid or other form. Stream 102 can include an oxygen-enriched stream in some embodiments. An oxygen-enriched stream refers to any stream having an oxygen concentration higher than the atmospheric concentration of oxygen. Oxygen stream 102 can be obtained from an oxygen storage tank or through an oxygen enrichment process, such as the separation of air into nitrogen and oxygen, such as pressure swing adsorption (PSA), vacuum swing adsorption (VSA), or cryogenic separation techniques, at the desired purity. The oxygen in oxygen stream 102 can have at least about 70 volume %, at least 80 volume %, or at least 90 volume % oxygen (e.g., 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, or 100 volume % oxygen). Although shown as three separate streams in FIG. 1, the components can be provided in a single or otherwise combined stream. The recycle gas stream can also be combined with the inlet stream as described in more detail herein.

[0020] The feed stream can be preheated in a preheater 108 and introduced into the carbon production reactor 110 together with a catalyst stream 112 containing a catalyst. The individual feed streams can be at any suitable pressure and temperature, as well as one or more heat exchangers (e.g., A preheater 108, etc.) can be used to adjust the temperature of the corresponding stream. The combined stream may have a pressure of from about 1 bar to about 50 bar, or from about 5 bar to about 20 bar. The preheater 108 can be used to heat the incoming combined stream to a temperature of from about 200 °C to about 700 °C, or from about 250 °C to about 400 °C, which can be the inlet temperature to the carbon formation reactor 110.

[0021] In the carbon formation reactor 110, carbon is produced together with H2 and H2O. Various reactions can occur that can result in the production of solid carbon as well as other reaction products including hydrogen, water, CO, and CO2 according to the following reactions: 2CO⇔C+CO2 CO2+CH4⇔2CO+2H2 H2O+CH4⇔CO+3H2 O2+2CH4⇔2CO+4H2 CO+H2⇔C+H2O CO+H2O⇔CO2+H2

[0022] The reactions that occur are both exothermic and endothermic. The reaction conditions in the carbon formation reactor 110 may include a pressure of from about 1 bar to about 50 bar, or from about 1 bar to about 20 bar, and a temperature of from about 400 °C to about 1000 °C, or from about 500 °C to about 750 °C. The temperature in the reactor may be maintained by providing a thermally insulated reaction vessel and / or by providing the reactants into the reactor at the desired temperature to maintain the temperature within the desired range. The carbon formation reactor 110 can take various forms, such as a fixed bed reactor, a fluidized bed reactor, or a moving bed reactor, etc.

[0023] The reactor can promote the reaction and the production of solid carbon using a catalyst. The catalyst material can include any material suitable for catalyzing the production of solid carbon materials from carbon oxides and gaseous reducing materials. By way of example, the catalyst material can be an element of Group VI, Group VII, Group VIII, Group IX, or Group X of the periodic table (e.g., iron, nickel, molybdenum, platinum, chromium, cobalt, tungsten, etc.), an actinide, a lanthanide, their oxides, their alloys, or combinations thereof. Any metal known to be subjected to metal coking can also be suitable for use as a catalyst material.

[0024] The catalyst material can be provided within the carbon production reactor 110 (e.g., within the reaction chamber) as one or more solid structures (e.g., particles, wafers, cylinders, plates, sheets, spheres, pellets, meshes, fibers, etc.) and / or as at least a partial coating on another structure within the reaction vessel (e.g., particles of at least one material deposited on a structure such as a wafer, cylinder, plate, sheet, sphere, mesh, pellet, etc.). In some embodiments, the catalyst material can be provided as a plurality of particles or particulate matter within the reactor. The catalyst material can be stationary (e.g., as a catalyst bed) or mobile (e.g., as a fluidized bed) within the reactor. In some embodiments, a portion of the catalyst material can be mobile within the reactor and another portion of the catalyst material can be stationary within the reactor.

[0025] As an example, the catalyst for the carbon formation reaction can include an iron-based catalyst. Without intending to be limited by theory, dissociated carbon (e.g., methane dissociated in contact with iron, and / or one or more carbon oxides in the reactor) can contact iron (e.g., ferrite) in the catalyst to form iron carbide. The iron carbide can then dissociate to reform the ferrite along with a layer of carbon on the ferrite (e.g., such as graphite). The process can continue and can result in the accumulation of a carbon layer on the ferrite, and as the thickness of the carbon layer on the iron increases due to an increase in the diffusion resistance to the reactive iron core, the reaction rate can decrease. The catalyst can then be deactivated with sufficient carbon layer accumulation.

[0026] The formation of solid carbon then occurs on or around the catalyst, and as a result, the removal of solid carbon from the reaction vessel (e.g., using a separator, e.g., a cyclone, a settling chamber, etc.) can also result in the removal of the catalyst from the reactor. As a result, a small amount of catalyst may be introduced into the carbon formation reactor 110 along with the reactants, and along with this, a corresponding amount of catalyst may be removed along with the solid carbon. In some embodiments, the amount of catalyst added to the reactor may have a mass ratio of catalyst to reactants of from about 0.0001:1 to about 1:1, or from about 0.001:1 to about 0.1:1.

[0027] As shown in FIG. 1, a catalyst stream 112 containing a catalyst may be introduced into the carbon formation reactor 110. The catalyst may include an oxide, and in addition to the oxygen obtained in the oxide, the oxygen in the CO may produce some amount of water in the gaseous product stream from the carbon formation reactor 110. The product from the carbon formation reactor can then include a gaseous product stream containing CO, H2O, H2, and CO2, and along with this, the solid product stream can include solid carbon along with the catalyst or a portion of the catalyst. The solid product stream can be removed from the carbon formation reactor 110 as a separate product stream from the gaseous product stream and can be removed from the system 100.

[0028] The carbon production reactor 110 can produce solid carbon that can be removed as a solid stream and a gaseous stream containing CO, H2O, H2, and CO2. The reaction can result in an outlet temperature in the range of 400 to 750 °C, and the solid stream can be transferred to one or more heat exchangers 114, 116 to cool the solid product. The first heat exchanger 114 can serve as a heat recovery steam generator to produce steam for use within the system. A further trim cooler 116 can be used to produce a solid stream 118 that can leave the system for further processing. The solid stream can mainly contain carbon along with any amount of catalyst material contained therein. In some embodiments, the mass ratio of solid carbon to catalyst material can be in the range of about 500:1 to about 1:1, or in the range of about 50:1 to about 5:1.

[0029] The gaseous product leaving the carbon production reactor 110 can be transferred to a heat exchanger 120 to cool the product. Similar to the solid product, the hot gaseous product can be cooled in the exchanger 120 that can serve as a heat recovery steam generator to generate steam. The cooled gas stream can then be transferred to a condenser 122. The condenser 122 can be used to remove any excess water from the stream as condensed steam. In the system 100 of FIG. 1, the addition of oxygen into the carbon production reactor 110 can result in the presence of excess oxygen. The oxygen can leave the system as water in the condensed water stream, and as a result, the oxygen is removed as water rather than CO2.

[0030] The remaining gas stream from condenser 122 can mainly contain CO2, H2, and unreacted hydrocarbons, although some trace compounds may also be present. Hydrogen in the stream can be removed in separator 126 to produce hydrogen stream 124. As shown in FIG. 1, a separation unit 126, such as a pressure swing adsorption (PSA) unit, can be used to separate at least a portion of the hydrogen from the product stream from condenser 122. Although shown as a PSA unit, other suitable separation units, such as temperature swing adsorption and membrane units, can also be used to separate at least a portion of the hydrogen. In some embodiments, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% (by volume) of the hydrogen in the product stream from condenser 122 is separated in separation unit 126 to produce hydrogen product stream 124 and a recycle stream having a reduced hydrogen concentration.

[0031] The remaining unreacted hydrocarbons and CO2 in the recycle stream can be compressed in compressor 128 and cooled in heat exchanger 130 to produce stream 132, which can be recycled to the inlet of carbon formation reactor 110.

[0032] The overall system 100 can be used to convert a hydrocarbon-containing feed to produce solid carbon and hydrogen. A higher hydrogen output can be obtained by reducing or eliminating the amount of CO2 provided to carbon formation reactor 110, and more CO2 can be consumed to produce carbon by limiting or eliminating the amount of hydrogen production. The addition of oxygen to enable the reforming reaction to operate in an autothermal mode can result in the introduction of additional oxygen that is removed as water and / or CO2, although removal as water can help prevent the generation of CO2 from the system.

[0033] In some embodiments, the system can also be used to convert the CO2 introduced into the system into solid carbon and water, thereby capturing the CO2 as solid carbon. The conversion of CO2 to carbon can be improved, for example, by bypassing the separator 126, without removing all or part of the hydrogen using the separator 126.

[0034] Another embodiment of the system 200 for hydrocarbon reactions is shown in FIG. 2. The system 200 is similar in many respects to the system 100 described with respect to FIG. 1. Additional components are shown in the system 200, and any one or more of them may also be present in the system 100 of FIG. 1. As shown in FIG. 2, a hydrocarbon stream 202 containing one or more hydrocarbons, including any of those described herein, can be combined with a recycled stream 204 containing CO2 and / or an external CO2 stream 203 containing CO2, a recycle stream 206 containing unreacted hydrocarbons, and an optional water stream 208 (e.g., provided as steam, etc.) to produce a combined feed stream 210. The individual feed streams can be at any suitable pressure and temperature, and one or more heat exchangers (e.g., heat exchanger steam generator 209, etc.) can be used to adjust the temperature of the corresponding streams. The individual feed streams can be combined in any order and at any location, including by being introduced individually or in combination into the reformer 212. The combined feed stream 210 may have a pressure of from about 1 bar to about 50 bar, or from about 5 bar to about 20 bar. The heat exchanger 211 can be used to heat the incoming combined stream 210 to a temperature of from about 400°C to about 700°C, or from about 500°C to about 600°C, which can be the inlet temperature to the reformer 212.

[0035] In addition to the incoming combined feed stream 210, an oxygen stream 214 may be introduced into the system 200. One or more units, such as compressor 216 and heat exchanger 218, may be used to condition the oxygen stream 214 for introduction into the reformer 212. The oxygen stream can, in some embodiments, include an oxygen-enriched stream. An oxygen-enriched stream refers to any stream having an oxygen concentration higher than the atmospheric concentration of oxygen. The oxygen stream 214 can be obtained at the desired purity from an oxygen storage tank or from an oxygen enrichment process, such as the separation of air into nitrogen and oxygen, such as pressure swing adsorption (PSA), vacuum swing adsorption (VSA), or cryogenic separation techniques. The oxygen in the oxygen stream 214 can have at least about 70 volume %, at least 80 volume %, or at least 90 volume % oxygen (e.g., 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, or 100 volume % oxygen).

[0036] Within the reformer 212, both combustion and reforming reactions can occur, and the reformer 212 can operate in an autothermal mode with an appropriate ratio of hydrocarbon to oxygen. The exothermic combustion reaction can occur according to the following (using methane as an example): CH4 + 2O2 → CO2 + 2H2O

[0037] The resulting CO2 and water, in addition to the CO2 and water in the inlet stream 210, can then undergo one or more of the reforming reactions described herein to produce CO and H2. The use of the exothermic combustion reaction can supply the heat required to drive the reforming reaction within the reformer 212, which can reduce the need for any external heating of the reformer.

[0038] The reformer 212 can operate under any suitable conditions and catalysts to produce CO and H2. The use of the reformer 212 can enable the reforming of hydrocarbons in the feedstock, which includes the gasification of heavy feedstocks such as biomass, crude oil, and coal using oxygen or other oxygen carriers (such as H2O, CO2, etc.) (as provided in stream 214 for example). In some cases, the operation of the reformer 212 may be endothermic to some extent, and heat can be provided directly or indirectly. If any part of the heat is supplied through means other than the introduction of O2 into the reformer 212, the heat source may be generated using a CO2 - free source such as through the combustion of hydrogen, and / or using an electrical source. In some embodiments where electrical heating is used, the electricity can be generated using a green source such as wind or solar power.

[0039] In some embodiments, the reformer 212 can function using dry reforming of methane (DRM). The dry reforming of hydrocarbons occurs according to the following reaction: CH4 + CO2 ⇔ 2CO + 2H2 (ΔH of about 260 kJ / mol at 1,000 °C)

[0040] The DRM unit can carry out the reforming reaction in a reaction vessel, and the reaction vessel can contain a catalyst to improve the reforming reaction rate. The reactor can take various forms, such as a fixed - bed reactor, a fluidized - bed reactor, or a moving - bed reactor, etc. The hydrocarbon feed can contain an equimolar or approximately equimolar amount of hydrocarbons such as methane and carbon dioxide. Although described as containing methane, other hydrocarbon - containing streams, including any of those described herein, can also be used. When the DRM unit is used as the reformer 212, the feed to the reformer 212 may not contain water or may contain substantially no water.

[0041] When the DRM unit is used as reformer 212, reformer 212 may optionally contain any suitable catalyst. Exemplary catalysts can include supported or bulk catalysts containing Group VIII (columns 8-10), Group IX, or Group X metals that are catalytically active towards reforming reactions. By way of example, catalysts based on nickel, cobalt, rhodium, ruthenium, or platinum or any combination thereof can be used in dry methane reforming.

[0042] When the DRM unit is used as reformer 212, the reaction conditions within reformer 212 are a pressure of about 1 bar to about 50 bar, or about 1 bar to about 20 bar, a temperature of about 750 °C to about 1100 °C, or about 800 °C to about 950 °C, and a GHSV of about 500 h -1 ~ about 100,000 h -1 may be included. In some embodiments, the conversion of hydrocarbons (e.g., methane, etc.) in the reaction can be about 60% to about 80%. The ratio of hydrogen gas to carbon monoxide (H2 / CO) in the product stream leaving reformer 212 can be in the range of about 0.5 to about 1. In some aspects, the ratio of hydrogen gas to carbon monoxide (H2 / CO) in the product stream leaving reformer 212 can be at least about 0.1, at least about 0.25, at least about 1, or at least about 1.5, and / or the ratio of hydrogen gas to carbon monoxide (H2 / CO) in the product stream leaving reformer 212 can be less than about 10, less than about 8, less than about 6, less than about 4, or less than about 2. Additionally, some amount of unreacted hydrocarbon gas and carbon dioxide can also be present depending on the overall conversion.

[0043] In some aspects, reformer 212 can function as a steam methane reformer (SMR). The SMR unit can carry out the reaction of water with a hydrocarbon feed to produce CO and H2. An exemplary SMR reaction using methane as an example can proceed according to: CH4 + H2O ⇔ CO + 3H2 When CO2 is introduced together with hydrocarbons and water, some amount of dry reforming can also occur according to the following: CH4 + CO2 ⇔ 2CO + 2H2 CO2 + H2 ⇔ CO + H2O

[0044] The SMR unit can carry out the reforming reaction in a reaction vessel, and the reaction vessel can contain a catalyst for improving the reforming reaction rate. The hydrocarbon feed can include any of the hydrocarbon feeds described herein, such as methane. The feed to the SMR unit can also include steam. In some embodiments, the reformer can include any suitable reactor, such as a tubular reactor and a multitubular reactor, or combinations thereof.

[0045] In some embodiments, the SMR unit can include a nickel-based catalyst (e.g., a sulfur-sensitive nickel-based catalyst) and / or a sulfur-passivated nickel-based catalyst (to avoid carbon deposition). The reforming reaction for hydrocarbons, such as methane, can be endothermic, and the reaction rate depends on temperature, pressure, and catalyst type. The endothermic nature of the reforming reaction can be balanced with an exothermic reaction based on the reaction of oxygen with hydrocarbons such that the overall reaction is autothermal or substantially autothermal. Hydrocarbons can undergo the reforming reaction at high temperatures, but in the presence of a catalyst (e.g., a nickel-based catalyst), the temperature at which the hydrocarbons can be reformed can be reduced. The SMR reaction can be carried out at a temperature of about 700 °C to about 1100 °C, or about 800 °C to about 900 °C. In one embodiment, the reformer can be characterized by a reforming pressure of about 1 bar to about 30 bar.

[0046] The outlet stream from the reformer 212 can be at a reformer 212 operating temperature of about 700 °C to about 1100 °C. The outlet stream can pass through a heat exchanger 211 to cool the outlet stream while heating the combined feed stream 210. The outlet stream leaving the exchanger can be cooled to about 200 °C to about 400 °C in the exchanger 211. The outlet stream can be further cooled in a second exchanger 220 to cool the outlet stream and condense at least a portion of any remaining water. The heat exchanger 220 can be any suitable exchanger and, in some embodiments, may include a heat recovery steam generator for generating steam within the system. The stream can then be cooled to 0 °C to 50 °C, or less than 30 °C, in a condenser 222 to condense at least a portion of the water in the outlet stream. The condensed water can be removed as a water stream 224. If a higher level of water removal is required, additional or alternative units, such as a glycol dehydrator, can be used. The remaining stream 225 can then contain CO, CO2, H2, unreacted hydrocarbons, and trace amounts of water.

[0047] Stream 225 can then move to a CO2 removal unit 226 to separate at least a portion of the CO2 in stream 225 and recycle it to the inlet of the reformer. The CO2 removal unit 226 can include any suitable unit and process for removing CO2. Such units can include, for example, membrane units, cryogenic separation units, and CO2 absorption units. In some embodiments, the CO2 can be removed using a CO2 absorption process. In this process, the CO2 is absorbed into a solvent to produce a CO2-loaded rich solvent. The rich solvent so produced can then be regenerated by flash regeneration at various pressures. Such a process can remove substantially all of the CO2 in the stream, leaving a residual product stream 225 having a very low CO2 content (typically less than 2 mol%, more typically less than 1 mol%). Suitable solvents, absorbents, and flash units are generally available. The removed CO2 in stream 232 can be sent to a compressor 234 and then moved to a heat exchanger 236 to produce a recycled stream 204 as part of the inlet stream to the reformer 212.

[0048] The remaining portion of stream 225 can move to separator 228. Separator 228 can include any of the separator units described with respect to FIG. 1. Although shown as a pressure swing adsorption unit, any suitable separation unit for separating hydrogen from stream 225 can be used. The separated hydrogen in stream 230 can leave system 200. The remaining stream can be produced from CO, unreacted hydrocarbons, and trace components including water, CO2, and hydrogen (along with some potential trace compounds). The stream can move to compressor 238 and heat exchanger 240 for cooling and compression and then move as stream 242 to heat exchanger 246. An additional amount of hydrocarbons in stream 244 can be combined with stream 242 to provide the desired ratio of CO to hydrocarbons fed to carbon production reactor 250. Heat exchanger 246 can serve as a feed preheater for heating the combined feed stream fed to carbon production reactor 250. Carbon production reactor 250 can be the same as carbon production reactor 110 described with respect to FIG. 1. The catalyst in stream 248 can be moved to carbon production reactor 250 for use in the production of solid carbon. The catalyst can include any of the catalysts described with respect to stream 112 in FIG. 1.

[0049] Carbon production reactor 250 can carry out any of the reactions described with respect to FIG. 1 to produce solid carbon that can be removed as a solid stream and a gaseous stream containing CO, H2O, H2, and CO2. The reaction can result in an outlet temperature in the range of 400 to 700 °C, and the solid stream can move to one or more heat exchangers 252, 254 to cool the solid product 256. The first heat exchanger 252 can serve as a heat recovery steam generator for producing steam for use within the system. A further trim cooler 254 can be used to produce a solid stream that can leave the system for further processing.

[0050] The gaseous product can be moved to the heat exchanger 258 to cool the product. Similar to the solid product, the hot gaseous product can be cooled in the exchanger 258 which can act as a heat recovery steam generator to generate steam. The cooled gaseous product can then be moved to an optional WGS unit 260. The WGS unit can function to shift CO and water to produce CO2 and hydrogen in the gaseous stream. In the WGS unit 260, CO and water react according to the WGS reaction as follows to produce CO2 and H2: CO + H2O ⇔ CO2 + H2

[0051] The WGS reaction is exothermic and is affected by temperature, with a higher conversion of CO at lower temperatures. The inlet heat exchanger (e.g., heat exchanger 258) can be used to obtain the desired temperature of the gaseous product stream from the carbon formation reactor 250. The WGS unit 260 can take various forms including the use of one or more fixed bed reactors. If multiple reactors are used, one or more inter-stage heat exchangers (e.g., coolers, etc.) can be used to maintain the desired temperature within the reactors. The reaction conditions within the WGS unit 260 may include a pressure of about 1 bar to about 50 bar, or about 1 bar to about 20 bar, and a temperature of about 150°C to about 500°C, or about 200°C to about 400°C.

[0052] The WGS reaction can occur in the presence of a WGS catalyst. The WGS shift catalyst may be provided and supported in any suitable form for performing the WGS reaction. For example, the shift catalyst may be provided as a fixed bed arranged in a shift reactor such that gas can flow through the catalyst layer. Examples of suitable WGS catalysts can include, but are not limited to, cobalt-molybdenum (Co-Mo), nickel-molybdenum (Ni-Mo) catalysts, chromium or copper promoted iron-based catalysts, zinc oxide promoted copper catalysts, or any combination thereof.

[0053] The product stream from the WGS unit 260 can have a reduced CO and water content compared to the gaseous product stream from the carbon formation reactor 250. The product stream may then mainly contain CO2 and H2 along with small or trace amounts of CO, water, and potentially unreacted hydrocarbons from the carbon formation reactor 250.

[0054] In some embodiments, the system 200 may not have a WGS unit 260. In these embodiments, the gaseous product leaving the exchanger 258 can move directly to the condenser 262. The stream 266 can then also contain a greater amount of CO compared to a system including the WGS unit 260. The CO can then move to return to the inlet of the reformer 212 in the recycle stream 206.

[0055] The condenser 262 can be used to remove any excess water from the stream after the WGS unit 260 as the condensed stream 264. In the system 200 of FIG. 2, the addition of oxygen into the reformer 212 can result in the presence of excess oxygen. The oxygen can leave the system as water in the streams 224 and / or 264, such that the oxygen is removed as water rather than CO2.

[0056] The remaining gas stream 266 can mainly contain CO2, H2, and unreacted hydrocarbons, although some trace compounds may also be present. The hydrogen in the stream can be removed in the separator 268 to produce a hydrogen stream 269. The separator 268 can include any of the separator units described with respect to FIG. 1. Although shown as a pressure swing adsorption unit, any suitable separation unit for separating hydrogen from the stream 266 can be used. The remaining unreacted hydrocarbons and CO2 can be compressed in the compressor 270 and cooled in the heat exchanger 272 to produce a stream 206, which can be recycled to the inlet of the reformer 212.

[0057] The overall system 200 can be used to carry out the reaction of hydrocarbons to produce solid carbon and hydrogen. The addition of oxygen to enable the reforming reaction to operate in an autothermal mode results in the introduction of additional oxygen that can be removed as water and / or CO2, and removal as water can help prevent the generation of CO2 from the system.

[0058] In some embodiments, the system can also be used to convert CO2 introduced into the system into solid carbon and water, thereby capturing CO2 as solid carbon.

[0059] Another system 300 for producing solid carbon and hydrogen is shown in FIG. 3, which uses a reverse water gas shift (rWGS) reactor 304 to convert CO2 to CO using H2. As shown, an inlet stream 302 containing CO2 can be provided to the system, and can be combined with a second recycle stream 352 containing CO2 and optionally some amount of H2, in addition to a recycle stream 314 containing CO2 and H2. The combined stream, mainly containing CO2 and H2, can be heated in an exchanger 306 and then moved to the rWGS reactor 304. The exchanger 306 can include any of the exchangers disclosed herein and can heat the combined feed stream to a temperature of about 200° C. to about 700° C., depending on the nature of the rWGS reactor 304.

[0060] The rWGS reactor can convert CO2 to CO using H2 according to the following equation: CO2 + H2 ⇔ CO + H2O

[0061] The rWGS reaction can be operated in the presence of one or more catalysts. Suitable catalysts can include those selected from the group consisting of ZnO, MnO x , and alkaline earth metal oxide composites (or mixed metal) oxides. Further rWGS catalysts are known in the art.​

[0062] The rWGS reaction can be carried out in one or more suitable reactors, such as adiabatic or heated reactors. Reaction vessels, such as fixed-bed reactors or fluidized-bed reactors, can be used. For example, the rWGS reactor can include a fixed-bed catalyst disposed in one or more tubular reactors configured within an adiabatic reactor or a thermal reactor, and the tubular reactor is externally heated. The rWGS reactor can be operated at a temperature within the range of about 500 °C to about 800 °C, and any suitable pressure used within the system, such as about 1 bar to about 50 bar, or about 5 bar to about 20 bar. The conversion efficiency of CO2 to CO can exceed 30%.

[0063] The stream leaving the reverse water-gas shift (rWGS) rWGS reactor 304 can be moved to a condenser 310 to remove at least a portion of the water produced in the rWGS reactor 304. The condenser 310 can be the same as or similar to the condenser described with respect to FIGS. 1 and 2. The resulting water stream 308 can then leave the system. The remaining stream can then be moved to a CO separation system 312 to separate CO from CO2 and H2 in the stream. Various CO separation systems can be used that include a solvent-based system for selectively separating CO from the remaining components containing CO2 and H2. One exemplary solvent-based process uses the complexation / decomplexation of carbon monoxide in a solvent containing a cuprous aluminum chloride (CuAlCl4) dissolved in an organic liquid, such as toluene, known as the trademark COPure from R.C. Costello & SM Assoc. Inc., Redondo Beach, California. Other suitable separation processes can also be used, and the CO separation system 312 includes a sequential separation of H2 and CO2 (in either order) from a stream using an adsorption and / or solvent-based system. The remaining CO can then be used in the remaining part of the process.

[0064] The obtained CO2 and H2 separated from the outlet of the capacitor 310 can be recycled as stream 314 to the inlet of the rWGS reactor 304 for further conversion. Stream 316 can contain mostly CO along with any trace amounts of other components including CO2, H2, and water. Stream 316 can be moved to the compressor 318. Additional components can be combined with stream 316 before and / or after its movement to the carbon production feed preheater 326. In some embodiments, the recycle stream 358 containing unreacted hydrocarbons and CO can be combined with the CO stream 316. Additional hydrocarbons can be added from stream 322, and oxygen can be added into stream 320. The hydrocarbons in stream 322 can include any of the hydrocarbons described herein, and the oxygen can be provided as an oxygen-enhanced stream. The amount of each component can be controlled to provide the desired ratio of hydrocarbons, oxygen, and CO in the feed to the carbon production reactor 328. In some embodiments, oxygen may be added if an increase or maximization of hydrogen production from the system 300 is desired, and the oxygen addition may be reduced or eliminated if the conversion of CO2 to solid carbon is desired.

[0065] The carbon production feed preheater 326 can be any suitable exchanger described herein. The feed to the carbon production reactor 328 can be heated to a temperature of about 200°C to about 700°C before its movement to the carbon production reactor 328. The carbon production reactor 328 can be the same as the carbon production reactor 110 or the carbon production reactor 250 described with respect to FIGS. 1 and 2. The catalyst in stream 324 can be moved to the carbon production reactor 328 for use in the production of solid carbon. The catalyst can include any of the catalysts described with respect to stream 112 or stream 248 in FIGS. 1 and 2.

[0066] The carbon production reactor 328 can carry out any of the reactions described with respect to FIG. 1 to produce solid carbon that can be removed as a solid stream and a gaseous stream containing CO, H2O, H2, and CO2. The reaction can result in an outlet temperature in the range of 400 to 700 °C, and the solid stream can be transferred to one or more heat exchangers 330, 332 to cool the solid product. The first heat exchanger 330 can act as a heat recovery steam generator to produce steam for use within the system. A further trim cooler 332 can be used to produce a solid stream 334 that can leave the system for further processing.

[0067] The gaseous product can be transferred to a heat exchanger 336 to cool the product. Similar to the solid product, the hot gaseous product can be cooled in the exchanger 336 that can act as a heat recovery steam generator to generate steam. The cooled gaseous stream can then be transferred to a condenser 262, which can be used to remove any excess water from the stream after the heat exchanger 336. In the system 300 of FIG. 3, the addition of oxygen to the feed to the carbon production reactor can result in the presence of excess oxygen. The oxygen can leave the system as water in the streams 308 and / or 340, such that the oxygen is removed as water rather than as CO2.

[0068] The remaining gas stream can mainly contain CO, CO2, H2, and unreacted hydrocarbons, although some trace compounds may also be present. The stream can be moved to a CO2 separation unit 342 to remove CO2 from the stream. The CO2 separation unit 342 can be the same as or similar to the CO2 removal unit 226 described with respect to FIG. 2, and can include any suitable unit and process for removing CO2. The removed CO2 in the stream can be sent to a compressor 344 and then moved to a heat exchanger 346 to produce a CO2 stream that can be combined with hydrogen to produce a recycle stream 352, and the recycle stream 352 can be sent to the inlet of the rWGS reactor 304.

[0069] The remaining components of the stream from the condenser 338 can be moved to a hydrogen separation unit 348, where at least a portion of the hydrogen can be separated from the unreacted hydrocarbons and CO. The hydrogen separation unit 348 can be the same as or similar to the separator 126 described with respect to FIG. 1. At least a portion of the separated hydrogen can leave the system as a hydrogen stream 350. A portion of the separated hydrogen can optionally be combined with the CO2 stream from the CO2 separation unit 342 to produce a recycle stream containing a blend of CO2 and H2. The remaining components, mainly containing unreacted hydrocarbons and CO, can be compressed in a compressor 354 and cooled in an exchanger 356 and then moved back to serve as part of the feed to the carbon formation reactor 328.

[0070] An additional system 400 for producing carbon is shown in FIG. 4. The system 400 is similar to the system 300 of FIG. 3, except that a reformer for producing CO from CO2 and H2 is replaced by an electrolyzer 404. The remaining elements of the system 400 can be the same as or similar to those described with respect to FIG. 3, and similar components are not described in detail for the sake of brevity.

[0071] As shown in FIG. 4, the CO2 feed in stream 302 can be combined with a recycle stream 402 containing CO2. The electrolyzer can convert CO2 to CO and O2 using an electrolysis process. The electricity for the electrolyzer 404 can be provided by any suitable source, and in some embodiments, the electricity can be provided by a source such as solar or wind power. The outlet stream from the electrolyzer 404 can contain CO, O2, and some amount of unreacted CO2. Depending on the amount of CO2 present in the outlet stream from the electrolyzer 404, an optional CO2 separation unit may be used. If the amount of CO2 is low, no additional separation unit is required prior to the transfer of CO and O2 to the carbon formation reactor 328. The electrolyzer 404 may also operate with low pressure drop, such that no additional compression or cooling is required prior to transfer to the carbon formation reactor 328.

[0072] Additional components can be combined with the electrolyzer output stream before and / or after transfer to the carbon formation feed preheater 326. In some embodiments, a recycle stream 408 containing unreacted hydrocarbons and CO can be combined with the electrolyzer output stream. Additional hydrocarbons can be added from stream 322, and oxygen can be added into stream 320. The hydrocarbons in stream 322 can include any of the hydrocarbons described herein, and the oxygen can be provided as an oxygen-enhanced stream. The amount of each component can be controlled to provide the desired ratio of hydrocarbons, oxygen, and CO in the feed to the carbon formation reactor 328. In some embodiments, oxygen may be added if an increase or maximization of hydrogen production from system 300 is desired, and oxygen addition may be reduced or eliminated if the conversion of CO2 to solid carbon is desired.

[0073] The carbon production feed preheater 326 can be any suitable exchanger described herein. The feed to the carbon production reactor 328 can be heated to a temperature of about 200°C to about 700°C before moving to the carbon production reactor 328. The carbon production reactor 328 can be the same as the carbon production reactor 110 or the carbon production reactor 250 described with respect to FIGS. 1 and 2. The catalyst in stream 324 can be moved to the carbon production reactor 328 for use in the production of solid carbon. The catalyst can include any of the catalysts described with respect to stream 112 or stream 248 in FIGS. 1 and 2.

[0074] The carbon production reactor 328 can carry out any of the reactions described with respect to FIG. 1 to produce solid carbon removed as a solid stream and a gaseous stream containing CO, H2O, H2, and CO2. The reaction can result in an outlet temperature in the range of 400 - 700°C, and the solid stream can be moved to one or more heat exchangers 330, 332 to cool the solid product. The first heat exchanger 330 can act as a heat recovery steam generator to produce steam for use within the system. A further trim cooler 332 can be used to produce a solid stream 334 that can leave the system for further processing.

[0075] The gaseous product can be moved to a heat exchanger 336 to cool the product. Similar to the solid product, the hot gaseous product can be cooled in the exchanger 336 that can act as a heat recovery steam generator to generate steam. The cooled gaseous stream can then be moved to a condenser 338, which can be used to remove any excess water from the stream after the heat exchanger 336. The addition of oxygen to the feed to the carbon production reactor can result in the presence of excess oxygen. The oxygen can leave the system as water in stream 340, such that the oxygen is removed as water rather than CO2.

[0076] The remaining gas stream can mainly contain CO, CO2, H2, and unreacted hydrocarbons, although some trace compounds may also be present. The stream can be moved to a CO2 separation unit 342 to remove CO2 from the stream. The CO2 separation unit 342 can be the same as or similar to the CO2 removal unit 226 described with respect to FIG. 2, and can include any suitable unit and process for removing CO2. The removed CO2 in the stream can be sent to a compressor 344 and then moved to a heat exchanger 346 to produce a CO2 stream that can produce a recycle stream 402 that can be sent to the inlet of the electrolyzer 404.

[0077] The remaining components of the stream from the condenser 338 can be moved to a hydrogen separation unit 348 where hydrogen can be separated from unreacted hydrocarbons and CO. The hydrogen separation unit 348 can be the same as or similar to the separator 126 described with respect to FIG. 1. The separated hydrogen can leave the system as a hydrogen stream 350. The remaining components mainly containing unreacted hydrocarbons and CO can be compressed in a compressor 354 and cooled in an exchanger 356 and then moved back to become part of the feed to the carbon production reactor 328.

[0078] Another system is shown in FIG. 5, which depicts system 500 for autothermal or exothermal C, H2, and H2O production from a feed containing hydrocarbons, O2 (e.g., in oxygen-containing stream 502), H2O, and CO2. A hydrocarbon stream 508 containing one or more hydrocarbons can be combined with a recycled stream 551 containing CO2, CO, H2, and hydrocarbons, an external CO2 stream 509, and an optional water stream 506 (e.g., provided as steam) to produce a combined feed stream 510. The hydrocarbons in hydrocarbon stream 508 can include any of those described herein, including light alkanes such as methane, ethane, natural gas, as well as other gaseous, liquid, and solid hydrocarbons (e.g., ethanol, crude oil, biomass, naphtha, etc.). In some embodiments, a gasification reactor can be used to convert one or more hydrocarbon-containing species into a gaseous stream. In some embodiments, the hydrocarbons can be provided as a fluidized solid or other form. The individual feed streams can be at any suitable pressure and temperature, and one or more heat exchangers (e.g., heat exchanger steam generator 507) can be used to adjust the temperature of the corresponding stream. The individual feed streams can be combined in any order and at any location, including by being individually or combinatorially introduced into reformer 512. The combined stream 510 can have a pressure of from about 1 bar to about 50 bar, or from about 5 bar to about 20 bar. Heat exchanger 511 can be used to heat the incoming combined stream to a temperature of from about 400 °C to about 800 °C, or from about 500 °C to about 600 °C, which can be the inlet temperature to reformer 512.

[0079] In addition to the combined streams entering at 510, an oxygen stream 502 may be introduced into the system 500. One or more units, such as compressor 504, may be used to condition the oxygen stream 502 for introduction into the reformer 512. The oxygen stream can, in some embodiments, include an oxygen-enriched stream. An oxygen-enriched stream refers to any stream having an oxygen concentration higher than the atmospheric concentration of oxygen. The oxygen stream 502 can be obtained from an oxygen storage tank or at a desired purity via an oxygen enrichment process, such as the separation of air into nitrogen and oxygen, such as pressure swing adsorption (PSA), vacuum swing adsorption (VSA), or cryogenic separation techniques. The oxygen in the oxygen stream 502 can have at least about 70 volume %, at least 80 volume %, or at least 90 volume % oxygen (e.g., 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.1, 99.2, 99.3, 99.4, 99.5, 99.6, 99.7, 99.8, 99.9, or 100 volume % oxygen).

[0080] Within reformer 512, both combustion and reforming reactions can occur, and the reformer 512 can operate in an autothermal mode with an appropriate ratio of hydrocarbon to oxygen. The exothermic combustion reaction can occur according to the following (using methane as an example): CH4 + 2O2 → CO2 + 2H2O

[0081] The resulting CO2 and water can, in addition to the CO2 and water in the combined feed stream 510, undergo one or more of the reforming reactions described herein to produce CO and H2. The use of the exothermic combustion reaction can supply the heat required to drive the reforming reaction within the reformer 512, which can reduce the need for any external heating of the reformer.

[0082] The reformer 512 can be operated under any suitable conditions and catalysts to produce CO and H2. Use of the reformer 512 can allow for the reforming of hydrocarbons in a feedstock, including gasification of heavy feedstocks such as biomass, crude oil, and coal using oxygen (e.g., as provided in stream 502) or other oxygen carriers (e.g., H2O, CO2, etc.). In some cases, operation of the reformer 512 may be endothermic to some extent, and heat may be provided directly or indirectly. If any portion of the heat is provided through other than the introduction of O2 into the reformer 512, the heat source may be generated using a CO2-free source, such as through the combustion of hydrogen, and / or using an electrical source. In some aspects when electrical heating is used, electricity may be generated using a green source, such as wind or solar power. In some embodiments, heat may also be provided from the carbon-producing reactor 524 when operated in an exothermic mode.

[0083] In some embodiments, the reformer 512 can function using dry reforming of methane (DRM). Dry reforming of hydrocarbons occurs according to the following reactions: CH4+CO2⇔2CO+2H2 (ΔH of approximately 260 kJ / mol at 1,000°C)

[0084] The DRM unit can carry out a reforming reaction in a reaction vessel, and the reaction vessel can be The reactor may contain a catalyst to improve the reaction rate. The reactor may take a variety of forms, such as a fixed bed reactor, a fluidized bed reactor, or a moving bed reactor. The hydrocarbon feed may contain equimolar or nearly equimolar amounts of a hydrocarbon, such as methane, and carbon dioxide. Although described as containing methane, other hydrocarbon-containing streams may also be used, including any of those described herein. When a DRM unit is used as the reformer 512, the feed to the reformer 512 may be free of water or substantially free of water.

[0085] When the DRM unit is used as reformer 512, reformer 512 may optionally contain any suitable catalyst. Exemplary catalysts can include supported or bulk catalysts containing Group VIII (columns 8-10), Group IX, or Group X metals that are catalytically active towards reforming reactions. By way of example, catalysts based on nickel, cobalt, rhodium, ruthenium, or platinum or any combination thereof can be used in dry methane reforming.

[0086] When the DRM unit is used as reformer 512, the reaction conditions within reformer 512 are a pressure of about 1 bar to about 50 bar, or about 1 bar to about 20 bar, a temperature of about 600 °C to about 1100 °C, or about 800 °C to about 950 °C, and a GHSV of about 500 h -1 ~ about 100,000 h -1 may be included. In some embodiments, the conversion of hydrocarbon (e.g., methane, etc.) in the reaction can be about 40% to about 80%. The ratio of hydrogen gas to carbon monoxide (H2 / CO) in the product stream leaving reformer 512 can be in the range of about 0.5 to about 1. In some aspects, the ratio of hydrogen gas to carbon monoxide (H2 / CO) in the product stream leaving reformer 512 can be at least about 0.1, at least about 0.25, at least about 1, or at least about 1.5, and / or the ratio of hydrogen gas to carbon monoxide (H2 / CO) in the product stream leaving reformer 512 can be less than about 10, less than about 8, less than about 6, less than about 4, or less than about 2. Additionally, some amount of unreacted hydrocarbon gas and carbon dioxide can also be present depending on the overall conversion.

[0087] In some aspects, reformer 512 can function using steam methane reforming (SMR). The SMR unit can perform the reaction of water with a hydrocarbon feed to produce CO and H2. An exemplary SMR reaction using methane as an example can proceed according to: CH4 + H2O ⇔ CO + 3H2 When CO2 is introduced together with hydrocarbons and water, some amount of dry reforming can also occur as follows: CH4 + CO2 ⇔ 2CO + 2H2 CO2 + H2 ⇔ CO + H2O

[0088] The SMR unit can carry out a reforming reaction in a reaction vessel, and the reaction vessel can contain a catalyst for improving the reforming reaction rate. The hydrocarbon feed can include any of the hydrocarbon feeds described herein, such as methane. The feed to the SMR unit can also include steam. In some embodiments, the reformer can include any suitable reactor, such as a tubular reactor and a multitubular reactor, or a combination thereof.

[0089] In some embodiments, the SMR unit can include a nickel-based catalyst (e.g., a sulfur-sensitive nickel-based catalyst) and / or a sulfur passivated nickel-based catalyst (to avoid carbon deposition). The reforming reaction for hydrocarbons, such as methane, can be endothermic, and the reaction rate depends on temperature, pressure, and catalyst type. The endothermic nature of the reforming reaction can be balanced with an exothermic reaction based on the reaction of oxygen with hydrocarbons such that the overall reaction is autothermal, near autothermal, or in some cases, exothermic. Hydrocarbons can undergo a reforming reaction at high temperatures, but in the presence of a catalyst (e.g., a nickel-based catalyst), the temperature at which hydrocarbons can be reformed can be reduced. The SMR reaction can be carried out at a temperature of about 700 °C to about 1100 °C, or about 800 °C to about 900 °C. In one embodiment, the reformer can be characterized by a reforming pressure of about 1 bar to about 30 bar. The endothermic nature of the reforming reaction can be balanced with an exothermic reaction based on the reaction of oxygen with hydrocarbons such that the overall reaction is autothermal, near autothermal, or in some cases, exothermic. Hydrocarbons can undergo a reforming reaction at high temperatures, but in the presence of a catalyst (e.g., a nickel-based catalyst), the temperature at which hydrocarbons can be reformed can be reduced. The SMR reaction can be carried out at a temperature of about 700 °C to about 1100 °C, or about 800 °C to about 900 °C. In one embodiment, the reformer can be characterized by a reforming pressure of about 1 bar to about 30 bar.

[0090] The outlet stream from the reformer 512 can be at a reformer 512 operating temperature of from about 700 °C to about 1100 °C. The outlet stream can pass through the exchanger 511 to cool the outlet stream while heating the combined inlet stream 510. The outlet stream leaving the exchanger can be cooled to from about 200 °C to about 400 °C in the exchanger 511. The outlet stream can be further cooled in a second exchanger 514 to cool the outlet stream and condense at least a portion of any remaining water. The heat exchanger 514 can be any suitable exchanger and, in some embodiments, may include a heat recovery steam generator for generating steam within the system. The stream can then be cooled to from 0 °C to 50 °C, or to less than 30 °C, in the condenser 516 to condense at least a portion of the water in the outlet stream. The condensed water can be removed as the water stream 518. If a higher level of water removal is required, additional or alternative units, such as a glycol dehydrator, etc., can be used. The remaining stream 519 can then contain CO, CO2, H2, hydrocarbons, and trace amounts of water.

[0091] Stream 519 then moves to preheater 520 where it can be preheated and introduced into carbon formation reactor 524 together with catalyst stream 522 containing a catalyst. In some embodiments, an optional stream 517 of CO2 can be introduced and mixed with stream 519 to adjust the amount of CO2 and / or the ratio of CO2 to other components in stream 519 prior to its movement to carbon formation reactor 524. In some embodiments, a reduced catalyst stream 521 can be introduced and optionally combined with catalyst stream 522 prior to the movement of the catalyst into carbon formation reactor 524. The individual feed streams can be at any suitable pressure and temperature, and one or more heat exchangers (e.g., preheater 520, etc.) can be used to adjust the temperature of the corresponding streams. The combined stream can have a pressure of from about 1 bar to about 50 bar, or from about 5 bar to about 20 bar. Preheater 520 can be used to heat the incoming combined stream 519 to a temperature of from about 200 °C to about 700 °C, or from about 250 °C to about 400 °C, which can be the inlet temperature to carbon formation reactor 524.

[0092] Within carbon formation reactor 510, solid carbon is produced along with H2O. Various reactions can occur that can result in the production of solid carbon and other reaction products including hydrogen, water, CO, and CO2 according to the following reactions: 2CO ⇔ C + CO2 (Boudouard reaction) CO + H2 ⇔ C + H2O CO2 + H2 ⇔ CO + H2O

[0093] The reactions that occur are both exothermic and endothermic. The reaction conditions in the carbon production reactor 524 may include a pressure of about 1 bar to about 50 bar, or about 1 bar to about 20 bar, and a temperature of about 400 °C to about 1000 °C, or about 500 °C to about 750 °C. The temperature in the reactor may be maintained by providing a thermally insulated reaction vessel and / or providing reactants into the reactor at a desired temperature to maintain the temperature within the desired range when the reactor is autothermal or substantially autothermal. When the reactor is operated exothermically, a cooling system (e.g., H2O cooling, preheating of the reactor feed, etc.) may be used. The carbon production reactor 524 can take various forms, such as a fixed bed reactor, a fluidized bed reactor, or a moving bed reactor, etc.

[0094] The reactor can use a catalyst to promote the reaction and the production of solid carbon. The catalyst material can include any material suitable for catalyzing the production of solid carbon materials from carbon oxides and gaseous reducing materials. By way of example, the catalyst material can be an element of Group VI, Group VII, Group VIII, Group IX, or Group X of the periodic table (e.g., iron, nickel, molybdenum, platinum, chromium, cobalt, tungsten, etc.), an actinide, a lanthanide, oxides thereof, alloys thereof, or combinations thereof. Any metal known to be subjected to metal coking may also be suitable for use as a catalyst material. The catalyst may also contain carbon, and in some embodiments, the catalyst may contain substantially pure carbon. For example, solid carbon, carbon on another particulate material (e.g., sand, catalyst, etc.), or other forms of carbon can be used. This can enable the solid carbon produced in the reactor to be used as a growth medium for the production of solid carbon, thereby making it possible to produce a carbon particulate material.

[0095] The catalyst material may be provided as one or more solid structures (e.g., particles, wafers, cylinders, plates, sheets, spheres, pellets, meshes, fibers, particulate matter, etc.) within the carbon production reactor 524 (e.g., within the reaction chamber), and / or as at least a partial coating on another structure within the reaction vessel (e.g., particles of at least one material deposited on a structure such as a wafer, cylinder, plate, sheet, sphere, mesh, pellet, etc.). In some embodiments, the catalyst material may be provided as a plurality of particles or particulate matter within the reactor. The catalyst material may be stationary (e.g., as a catalyst bed) or mobile (e.g., as a fluidized bed) within the reactor. In some embodiments, a portion of the catalyst material may be mobile within the reactor and another portion of the catalyst material may be stationary within the reactor.

[0096] By way of example, the catalyst for the carbon production reaction can include an iron-based catalyst. Without intending to be limited by theory, dissociated carbon (e.g., carbon monoxide dissociated in contact with iron, and / or hydrogen or carbon dioxide within the reactor) can contact iron (e.g., ferrite) within the catalyst to form iron carbide. The iron carbide can then dissociate to reform the ferrite along with a layer of carbon (e.g., graphite, etc.) on the ferrite. The process can continue and can result in the accumulation of a carbon layer on the ferrite, and the reaction rate can decrease as the thickness of the carbon layer on the iron increases due to an increase in the diffusion resistance to the reactive iron core. The catalyst can then become deactivated with sufficient carbon layer accumulation.

[0097] The formation of solid carbon then occurs on or around the catalyst, and as a result, the removal of solid carbon from the reaction vessel (e.g., using a separator, such as a cyclone, settling chamber, etc.) can also result in the removal of the catalyst from the reactor. As a result, a small amount of catalyst may be introduced into the carbon formation reactor 524 with the reactants, and along with this, a corresponding amount of catalyst may be removed with the solid carbon. In some embodiments, the amount of catalyst added to the reactor may have a mass ratio of catalyst to reactants of from about 0.0001:1 to about 1:1, or from about 0.001:1 to about 0.1:1.

[0098] As shown in FIG. 5, stream 519 may be introduced into the carbon formation reactor 524. The catalyst may include an oxide, and in addition to the oxygen obtained in the oxide, the oxygen in the CO may produce some amount of water in the gaseous product stream from the carbon formation reactor 524. The product from the carbon formation reactor can then include a gaseous product stream containing CO, H2O, H2, CO2, and hydrocarbons, and the solid product stream can include solid carbon with or without a portion of the catalyst. The solid product stream can be removed from the carbon formation reactor 524 as a separate product stream from the gaseous product stream and can be removed from the system 100. or can include solid carbon along with a portion of the catalyst. The solid product stream can be removed from the carbon formation reactor 524 as a separate product stream from the gaseous product stream and can be removed from the system 100.

[0099] The carbon production reactor 524 can produce solid carbon that can be removed as a solid stream, as well as a gaseous stream containing CO, H2O, H2, CO2, and hydrocarbons. The reaction can result in an outlet temperature in the range of 400°C to 700°C, and the solid stream can be transferred to one or more heat exchangers 526, 528 to cool the solid product. The first heat exchanger 526 can act as a heat recovery steam generator to produce steam for use within the system. A further trim cooler 528 can be used to produce a solid stream 530 that can leave the system for further processing. The solid stream can mainly contain carbon along with any amount of catalyst material (which may be carbon in some embodiments). In some embodiments, the mass ratio of solid carbon to catalyst material can be in the range of about 500:1 to about 2:1, or in the range of about 200:1 to about 100:1.

[0100] The gaseous product leaving the carbon production reactor 524 can be transferred to a heat exchanger 532 to cool the product. Similar to the solid product, the hot gaseous product can be cooled in the exchanger 532 that can act as a heat recovery steam generator to generate steam. The cooled gas stream can then be transferred to a condenser 534. The condenser 534 can be used to remove any excess water from the stream as a condensed stream 536. A higher level of water removal may require the processes previously described herein. In the system 500 of FIG. 5, the addition of oxygen into the reformer 512 can result in the presence of excess oxygen. The oxygen can leave the system as water in the condensed water stream, and as a result, the oxygen is removed as water rather than CO2.

[0101] In some optional embodiments, a portion of the gaseous stream 535 that has moved out of the capacitor 534 can move back to the inlet stream 519 to the carbon production reactor 524. A compressor or blower unit 538, which may include cooling for its feed and heating for its discharge, can be used to recycle all or a portion of the gaseous stream 535 to the carbon production reactor 524 inlet preheater 520. The gaseous stream 535 can include H2, CO, CO2, hydrocarbons, and unseparated H2O. The stream 535 can have a higher H2 to CO ratio than the stream 519 produced from the reformer 512. By recycling all or a portion of the stream 535, the carbon production reactor 524 can be operated at a higher H2 to CO ratio than when produced by the reformer 512.

[0102] The reverse water gas shift (rWGS) reactor 540 can be used to convert CO2 in the gaseous product stream 535 to CO using H2. The inlet stream 535, which includes CO2, CO, H2, and hydrocarbons, can be heated in an optional exchanger prior to moving to the rWGS reactor 540. The exchanger can include any of the exchangers disclosed herein and can heat the combined feed stream to a temperature of about 200°C to about 700°C, depending on the nature of the rWGS reactor 540.

[0103] The rWGS reactor can convert CO2 to CO using H2 according to the following equation: CO2 + H2 ⇔ CO + H2O

[0104] The rWGS reaction can be operated in the presence of one or more catalysts. Suitable catalysts can include those selected from the group consisting of ZnO, MnO, alkaline earth metal oxide composites (or mixed metal) oxides. Additional rWGS catalysts are known to those skilled in the art. nO x and can include those selected from the group consisting of alkaline earth metal oxide composites (or mixed metal) oxides. Additional rWGS catalysts are known to those skilled in the art.

[0105] The rWGS reaction can be carried out in one or more suitable reactors, such as adiabatic or heated reactors. Reaction vessels, such as fixed-bed reactors or fluidized-bed reactors, can be used. For example, the rWGS reactor can include a fixed-bed catalyst disposed in one or more tubular reactors configured within an adiabatic reactor or a thermal reactor, and the tubular reactor is externally heated. External heat can be provided by the carbon formation reactor 524, if it is exothermic, through direct heat exchange, steam, or any heat exchange method described herein. The rWGS reactor can be operated at a temperature in the range of about 500 °C to about 800 °C, and any suitable pressure used within the system, such as about 1 bar to about 50 bar, or about 5 bar to about 20 bar. The conversion efficiency of CO2 to CO can exceed 30%.

[0106] In some optional embodiments, the catalyst stream 537 can be moved through the rWGS reactor 540 during the reaction to produce a reduced catalyst in stream 539. The resulting catalyst stream can then be moved to return to the inlet of the carbon formation reactor 524 as stream 521. In this embodiment, a catalyst (e.g., fresh catalyst, catalyst with carbon from the carbon formation reactor 524, etc.) can be present within the rWGS reactor 540 during the reaction. Various species, such as carbon or any oxygen-containing species formed on the catalyst, can be reduced based on the presence of hydrogen and other species during the rWGS reaction. In some aspects, the resulting reduced catalyst may be more catalytically active than the catalyst entering the rWGS reactor 540, and then can be used within the carbon formation reactor 524 to further produce carbon for removal from the system 500.

[0107] The stream leaving the rWGS reactor 540 can be moved to a condenser 542 to remove at least a portion of the water produced in the rWGS reactor 540. The condenser 542 can be the same as or similar to the condensers described herein. The resulting water stream 544 can then leave the system.

[0108] The remaining gas stream 541 from the condenser 542 can mainly contain CO2, CO, H2, and hydrocarbons, but some trace compounds may also be present. The hydrogen in the stream can be removed in the separator 546 to produce a hydrogen stream 548. As shown in FIG. 5, a pressure swing adsorption (PSA) unit 546 can be used to separate at least a portion of the hydrogen from the product stream from the condenser 542. Although shown as a PSA unit, other suitable separation units, such as temperature swing adsorption and membrane units, can also be used to separate at least a portion of the hydrogen. In some embodiments, at least about 50%, at least about 60%, at least about 70%, at least about 80%, or at least about 90% (by volume) of the hydrogen in the product stream from the condenser 542 is separated in the separation unit 546 to produce a hydrogen product stream 548 and a recycle stream having a reduced hydrogen concentration.

[0109] The remaining hydrocarbons and CO2 in the recycle stream can be compressed in the compressor 550 and cooled in a heat exchanger to produce a stream 551, which can be recycled to the inlet of the reformer preheater 511 described herein.

[0110] The overall system 500 can be used to convert a hydrocarbon-containing feed to produce solid carbon and hydrogen. A higher hydrogen output can be obtained by reducing or eliminating the amount of CO2 provided to the reformer 512, and more CO2 can be consumed to produce carbon by limiting or eliminating the amount of hydrogen production. The addition of oxygen to enable the reforming reaction to operate in an autothermal mode can result in the introduction of additional oxygen that can be removed as water and / or CO2, but removal as water can help prevent the generation of CO2 from the system. The addition of oxygen to enable the reforming reaction to operate in an autothermal mode can result in the introduction of additional oxygen that can be removed as water and / or CO2, but removal as water can help prevent the generation of CO2 from the system.

[0111] In some embodiments, the system can also be used to convert the CO2 introduced into the system into solid carbon and water, thereby capturing the CO2 as solid carbon. The conversion of CO2 to carbon can be improved by, for example, not removing all or part of the hydrogen using separator 546, such as by bypassing all or part of the outlet stream of condenser 542 around separator 546.

[0112] The various systems described herein can also enable the promotion of the reduction of CO in the carbon formation reaction 124, thereby reducing the production of CO2 via the Boudouard reaction. The overall process can consume a catalyst within the carbon formation reactor. However, the catalyst can be of relatively low cost such that the system is cost-effective.

[0113] The systems described herein can be configured to receive a hydrocarbon stream and to produce a hydrogen and a solid carbon stream. Oxygen can be present within the system and can be used in a process to carry out the production of solid carbon from the hydrocarbon. If oxygen is introduced into the system (e.g., in a catalyst used in the carbon formation process), the oxygen can be removed as a water stream and / or a CO2 stream. The oxygen may be removed in the water stream to avoid the release of CO2 from the overall system.

[0114] The disclosed systems can be used in various processes for carrying out the production of solid carbon from one or more hydrocarbons and / or CO2. While specific systems are disclosed, a more general process is shown in FIG. 6. As shown, a process for converting a stream containing carbon (e.g., a hydrocarbon, a carbon oxide such as carbon dioxide, etc.) can be converted to solid carbon and, if hydrogen is present in the feed stream, a product stream containing hydrogen.

[0115] FIG. 6 shows one embodiment of a system 600 for producing hydrogen and carbon. As shown, a reactor system 602 including one or more reactors can be configured to receive a feed stream including hydrocarbons 608 and an oxidant 606 and to produce a product including solid carbon 612 and hydrogen gas 618. Any of the configurations described herein can be used to carry out the conversion of hydrocarbons using an oxidant to produce hydrogen and solid carbon.

[0116] The oxidant can include any compound containing oxygen, such as CO2, CO, O2, or H2O. Although the oxidant stream 606 and the CO2 stream 610 are shown as separate streams in FIG. 6, CO2 can be part of the oxidant stream 606. The hydrocarbons can include any of those described herein. The oxidant in the oxidant stream can react with the hydrocarbons to produce one or more intermediates that can be converted to hydrogen and solid carbon.

[0117] In some embodiments, one or more catalysts 604 can be used with the reactor system 602. The catalyst can be used to produce one or more intermediates and / or solid carbon. For example, any of the catalytic reactions described herein for converting reactants, such as CO2, H2O, or hydrocarbons, to intermediates, such as CO, can use a catalyst. The catalyst can also be used to produce solid carbon. For example, an iron-based catalyst can be used to produce solid carbon on a catalyst material, which can then be removed from the reactor. The product can then include a catalyst product 614, such as a catalyst with solid carbon disposed thereon.

[0118] In some embodiments, the oxidant stream 606 can be converted within the reactor system 602 to produce water that can leave the system as a water stream 616. This process can then convert the oxygen entering the system to water rather than carbon dioxide, thereby limiting the release of carbon as a gas, e.g., CO2. In some embodiments, the oxidant can include CO2 when introduced into the system, and the reactor system 602 can convert the CO2 to solid carbon and water.

[0119] The reactor system 602 can be configured to operate autothermally or exothermally. This can be advantageous in order to limit the amount of heat that needs to be added to the reactor, which can simplify the heat transfer and heat addition processes within the reactor system.

[0120] As shown in FIG. 6, a recycle system 620 can be provided as part of the system 600. In some embodiments, the recycle system 620 can include one or more separators for removing a portion of the product stream from the reactor system 602 and recycling the separated components to the inlet of the reactor system 602. For example, any unreacted oxidant, or alternatively any oxidant in the product stream other than water, can be separated and recycled to the inlet of the reactor system 602. As another example, any unreacted hydrocarbon can be separated and recycled. In some embodiments, some amount of hydrogen can be recycled within the system as needed to assist in the production of solid carbon.

[0121] As an example of such a system, the hydrocarbon in hydrocarbon stream 608 may be methane, and the oxidant in stream 606 can include O2, H2O, and / or CO2. An iron-based catalyst can be used in the reactor system, and solid carbon can be produced on the iron-based catalyst, which can then be removed from the system along with the solid carbon product as described in more detail in the embodiments disclosed herein. In such embodiments, the catalyst may be continuously added to the reactor system, and the catalyst with solid carbon disposed thereon may be continuously removed from the reactor to provide a continuous reaction process. Further, the system can operate according to any of the embodiments disclosed herein.

[0122] The various systems described herein also avoid the need for a high-temperature reaction medium, such as molten metal and / or molten salt, by enabling a balance of reforming reactions, Boudouard reactions, and CO reduction reactions. For example, combining a carbon formation reaction with a reforming reaction can allow the reforming reaction to operate in an endothermic manner and the Boudouard reaction and CO reduction reaction to operate as exothermic reactions to generate solid carbon. The overall process can consume the catalyst in the carbon formation reactor. However, the catalyst can be of relatively low cost such that the system is cost-effective.

[0123] The systems described herein can be configured to receive a hydrocarbon stream and to produce a hydrogen and solid carbon stream. Oxygen can be present within the system and can be used in a process to carry out the production of solid carbon from the hydrocarbon. When oxygen is introduced into the system (e.g., in the catalyst used in the carbon formation process), the oxygen can be removed as a water stream and / or a CO2 stream. The oxygen may be removed in the water stream to avoid the release of CO2 from the overall system.

[0124] The disclosed system can be used in various processes for producing solid carbon from one or more hydrocarbons and / or CO2.

[0125] Various reactor systems can be used in any of the embodiments disclosed herein. The reactor system can result in the reduction of carbon monoxide and other reactions, such as the reactions described herein (e.g., the Boudouard reaction, etc.), using a catalytic reactor with a recycle stream. In addition to the embodiments disclosed herein, FIG. 7 shows one embodiment of a system and associated process for reacting carbon monoxide and hydrogen to generate solid carbon and a gaseous product.

[0126] As shown, input stream 701 can be moved to recycle stream 707 and combined with recycle stream 707 prior to moving to carbon production reactor 728. Input stream 701 can contain carbon monoxide and hydrogen, and recycle stream 707 can also contain carbon monoxide and hydrogen. In some aspects, recycle stream 707 can be about 20% to about 95%, or alternatively about 50% to about 90% of the volume of dehydrated stream 705. In some aspects, substantially all of dehydrated stream 705 can be recycled, except for some amount that can be purged from the system. In these embodiments, recycle stream 707 can be about 20% to about 95%, or alternatively about 50% to about 90% of the volume of dehydrated stream 705.

[0127] The specific ratio of carbon monoxide to hydrogen in the combined stream 702 may be adjusted by supplying different ratios of hydrogen to carbon monoxide in the input stream 701 or by adjusting the relative amounts of the input stream 701 and the recycle stream 707. In some embodiments, the ratio of hydrogen to carbon monoxide by volume in the combined stream 702 can be from about 0.1:1 to about 10:1, from about 0.25:1 to about 5:1, or from about 1.5:1 to about 6:1. In some embodiments, additional components, such as carbon dioxide, water, and oxygen, may be present in minor or trace amounts.

[0128] In some embodiments, hydrocarbons may be present in the input stream 701 and / or the recycle stream 707, or alternatively or additionally, hydrocarbons may be added to either stream in the desired amounts. Hydrocarbons can include any of those described herein. In some embodiments, the presence of hydrocarbons may suppress side reactions, such as methanation in the carbon formation reactor, improving the overall process. When present, hydrocarbons may be present in an amount of about 1% to about 50% by volume of the combined stream 702, or at least about 10% by volume of the combined stream 702.

[0129] The combined feed stream 702 can then move to the carbonaceous product preheater 726, which can be any suitable exchanger described herein, including an indirect heat exchanger, a superheater, a gas-gas counterflow heat exchanger, or another heat exchanger. The feed to the carbonaceous reactor 728 can be heated to a temperature of about 200°C to about 750°C before moving to the carbonaceous reactor 728. The carbonaceous reactor 728 can be the same as the carbonaceous reactor 110 or the carbonaceous reactor 250 described with respect to FIGS. 1-5. The catalyst in stream 724 can be moved to the carbonaceous reactor 728 for use in the production of solid carbon. The catalyst can include any of the catalysts described with respect to stream 112 or stream 248 in FIGS. 1 and 2. In some embodiments, heat integration may be used to provide a more energy efficient system. As shown in FIG. 7, the carbonaceous product preheater 726 can heat the combined feed stream 702 and cool the product stream 704 by enabling indirect heat exchange between the combined feed stream 702 and the hotter product stream 704.

[0130] The carbon production reactor 728 can carry out any of the reactions described with respect to FIG. 1 in the presence of and in contact with a solid catalyst to produce solid carbon that can be removed as a solid stream and a gaseous stream containing CO, H2O, H2, and CO2. When the feed mainly contains carbon monoxide and hydrogen, the product may contain solid carbon produced on the catalyst and water, but numerous additional reactions occurring in the reactor can produce various by-products such as carbon dioxide, hydrogen, and methane. The catalyst can include any of the catalysts described herein, for example, elemental substances, oxides, or carbides of various metals such as iron, cobalt, or nickel. The carbon production reactor 728 can operate at a temperature in the reaction zone of about 500°C to about 900°C, or about 650°C to about 800°C. The reaction can result in an outlet temperature within the range of 400 to 800°C. The carbon production reactor 728 can operate at a pressure of about 1 bar to about 80 bar, or about 5 bar to about 40 bar, or about 10 bar to about 20 bar.

[0131] The conversion between reactors can vary based on the composition of the feed stream and the reaction conditions. In some embodiments, the carbon monoxide conversion in the reactor from the combined stream 702 to the product stream 703 can be up to about 60%, including about 60%. In some embodiments, the carbon dioxide conversion in the reactor from the combined stream 702 to the product stream 703 can be up to about 70%, including about 70%. In some embodiments, the hydrogen conversion in the reactor from the combined stream 702 to the product stream 703 can be up to about 30%, including about 30%.

[0132] In some embodiments, the carbon formation reactor 728 can be thermally controlled during the reaction. Various direct and indirect heat exchanges can be used during the reaction. For example, the control of the inlet gas temperature, such as the use of liquid water, boiling water, saturated or supersaturated steam, and the use of external heat exchange, such as a cooling jacket, can be used to control the temperature of the carbon formation reactor 728 during the reaction. In some aspects, additional reactions can be used to control the temperature within the carbon formation reactor 728, which can use, for example, an endothermic reforming reaction that converts hydrocarbons occurring in heat exchange tubes within the reactor into a syngas stream containing carbon monoxide and hydrogen. In some aspects, the carbon formation reactor 728 can be cooled during the reaction.

[0133] The product and unreacted reactants, including the catalyst and solid carbon product, can leave the carbon formation reactor 728 in stream 703. Since solids are entrained within the gas stream, the overall product stream 703 can be moved to a solid separator 721 to separate at least a portion of the solids, including solid carbon and solid catalyst, from the product stream 703. Any suitable solid separator, such as a cyclone, baghouse, and filter, etc., can be used. Although a single solid separator 721 is shown in FIG. 7, a number of solid separators arranged in series and / or in parallel can be used to process the expected volumes of gas and solids. A portion of the solids from the separated solid stream 711 may be recycled to the carbon formation reactor 728. Some solids may also be removed separately from the bottom of the reactor.

[0134] The solid separator 721 may then result in a solid stream 711 that can move out of the system. In some aspects, the solid stream can include solid carbon produced on the catalyst. The solid product can be used in the as-manufactured form can be used, and / or one or more additional processes can be used to remove at least a portion of the carbon from the catalyst such that the catalyst, or a portion thereof, can be reused and returned to the carbon production reactor 728. The amount of carbon produced in the carbon production reactor 728 may be based on the amount of catalyst that has been moved through the carbon production reactor 728. In some embodiments, the ratio of carbon to catalyst can be from about 2:1 to about 200:1 by mass, or alternatively from about 10:1 to about 50:1 by mass. In some embodiments, the ratio of carbon to iron in the catalyst can be from about 2:1 to about 200:1 by mass, or alternatively from about 5:1 to about 50:1 by mass.

[0135] The remaining gaseous product stream 704 can then be moved to one or more heat exchangers 722, 723 to further cool the gaseous product stream 704. The gaseous product stream 704 can include hydrogen, carbon monoxide, carbon dioxide, and water, and may contain some amount of hydrocarbons if hydrocarbons are present in the feed stream. In some embodiments, the gaseous product stream can be moved to a carbon production feed preheater 726 to provide heat integration to the exchanger, e.g., the system. One or more additional heat exchangers 722, 723 may provide trim cooling to the gaseous product stream 704 to produce a desired temperature output for the gaseous product stream 704.

[0136] The cooled gaseous product stream can then be moved to an optional additional solid separator 725. Any suitable solid separation device, such as one or more cyclones, baghouses, or filters, can be used to further remove solids from the cooled gaseous product stream. The separated solids can be combined with the solids in stream 711 or can be processed separately.

[0137] The cooled, solid-free gas product stream 712 can then move to condenser 738, which can be used to remove and separate at least a portion of the water from stream 712. The condensed water can then move out of condenser 738 as stream 714. The remaining gas stream from the condenser can include the dehydrated stream 705. The dehydrated stream can include carbon monoxide, hydrogen, and some amount of carbon dioxide. In some embodiments, hydrocarbons, such as methane, may be present in the feed gas, and the resulting dehydrated stream may include some amount of hydrocarbons as unreacted components. In some embodiments, the dehydrated stream 705 can have, on an all-volume basis, from about 5% to 40% carbon monoxide, 20 to 60% hydrogen, 0.5 to 15% carbon dioxide, and optionally from 0 to 50% hydrocarbons.

[0138] The dehydrated stream 705 can optionally be split into a first portion that creates recycle stream 707 and a second portion that creates outlet stream 708. The first portion can be combined with feed stream 701 after being sent to a compressor, blower, series of compressors, or series of blowers 744. The relative amount of recycle stream 707 combined with feed stream 701 can be based at least in part on the compositions of feed stream 701 and recycle stream 707.

[0139] The outlet stream 708 can be moved to an optional hydrogen separation unit 748, where at least a portion of the hydrogen can be separated from the remaining components. The hydrogen separation unit 748 can be the same as or similar to the separator 126 described with respect to FIG. 1, including, for example, an adsorption unit (e.g., a pressure swing adsorption unit, a temperature swing adsorption unit, etc.). The separated hydrogen can leave the system as hydrogen stream 709. The remaining components, mainly unreacted hydrocarbons and CO, can be moved to exit the system as stream 710. If stream 710 is used within the system, a portion of stream 710 may be purged (e.g., to the atmosphere) to prevent the accumulation of inert gases in the system. If a portion is purged, the portion may be about 1% to about 20% by volume, or in some embodiments, less than about 15% or less than about 10% by volume. In some embodiments, the hydrogen separation unit 748 may be used to adjust the relative amounts of the components in the syngas 708, for example, by increasing the ratio of carbon monoxide to hydrogen. This may enable stream 710 to be used in either the reaction system described herein or any other process that accepts syngas as a feed gas.

[0140] Although not shown in FIG. 7, additional solid separation may be used with any of the streams within the system downstream of the carbon formation reactor 728. For example, any of the solid separators described herein can be used downstream of a condenser, an H2 separator, or any other unit. The resulting solid stream can be combined with the solid stream or otherwise removed from the system.

[0141] Based on the recycle stream and the separation of solids, the systems and processes described with respect to FIG. 7 may operate without or substantially without direct CO2 emissions. For example, the only CO2 emissions may occur due to the purge stream to avoid the accumulation of inert gases within the system. In some embodiments, the system is less than 3 kg of CO per kg of H2 produced 2e at a level, or alternatively less than 1 kg of CO per kg of H2 produced at a level and may operate with direct CO, CO2, and CH4 emissions. In some embodiments, the purge stream is combusted with air to convert CO and CH4 to CO2, which can reduce the CO2 emission equivalent. 2e A similar reaction system is shown in FIG. 8. The main difference between FIGS. 7 and 8 is the addition of a carbon dioxide separation unit for separating at least a portion of the carbon dioxide from the dehydrated stream 705. As shown in FIG. 8, the dehydrated stream 705 moving out of the condenser 738 can be moved to a CO2 separation unit 742 to remove at least a portion of the CO2 from the stream. The CO2 separation unit 742 can be the same as or similar to the CO2 removal unit 226 described with respect to FIG. 2 and can include any suitable unit and process for removing CO2. The removed CO2 in the stream 705 can be moved out of the system as a CO2 stream 715. The remaining portion of the gas stream can be split into a first portion 707 that produces a recycle stream and a second portion 708 that produces an outlet stream, each of which can be processed as described with respect to FIG. 7. The use of the CO2 separation unit 742 can make it possible to adjust the composition of the dehydrated stream 705 while also producing a purified CO2 stream.

[0142]

[0143] ​FIG. 9 shows a carbon production reactor 900. The carbon production reactor 900 can be used in any of the embodiments disclosed herein, including any of those described with respect to FIGS. 1-8. As shown, a feed gas stream 902 can be supplied into the carbon production reactor 900, and the carbon production reactor 900 can contain a solid catalyst 906. The solid catalyst 906 can be introduced into the process as a solid stream 904. Within the carbon production reactor 900, the solid catalyst 906 can form a bed in which the components of the feed stream 902 can react to produce solid carbon on the solid catalyst 906. A portion of the solid carbon 908 can be removed from the solid catalyst 906 and entrained with the gas stream 910 exiting the reactor. The solid carbon 912 can then be separated in one or more downstream units.

[0144] The feed stream 902 can include any of the feed streams moving to the carbon production reactors described herein. The feed stream can include carbon monoxide and hydrogen, and optionally, carbon dioxide and / or hydrocarbons including any of those described herein. In some embodiments, additional components, such as oxygen and / or water, may also be present in the feed stream 902. In some embodiments, the ratio of hydrogen to carbon monoxide by volume in the feed stream 902 can be from about 1.5:1 to about 6:1. In some embodiments, the ratio of hydrogen gas to carbon monoxide (H2 / CO) in the feed stream 902 can be at least about 0.1, at least about 0.25, at least about 1, or at least about 1.5, and / or the ratio of hydrogen gas to carbon monoxide (H2 / CO) in the feed stream 902 can be less than about 10, less than about 8, less than about 6, less than about 4, or less than about 2. When present, the hydrocarbons can be present in an amount of about 1% to about 50% by volume of the combined stream 902, or at least about 10% by volume of the combined stream 902.

[0145] The catalyst introduced into the carbon formation reactor 900 in the solid stream 904 can include any of the catalysts described with respect to stream 112 or stream 248 in FIGS. 1 and 2. In some embodiments, the catalyst can include any material suitable for catalyzing the production of solid carbon materials from carbon oxides and gaseous reducing materials. By way of example, the catalyst material can be an element of Group VI, Group VII, Group VIII, Group IX, or Group X of the periodic table (e.g., iron, nickel, molybdenum, platinum, chromium, cobalt, tungsten, vanadium, titanium, tantalum, zirconium, hafnium, etc.), an actinide, a lanthanide, an oxide thereof, a carbide thereof, an alloy thereof, or a combination thereof. In some embodiments, the catalyst may not be supported, and as a result, the catalyst components are not disposed or supported on another material.

[0146] Within the carbon formation reactor 900, the catalyst can take various forms, such as a fixed bed reactor, a fluidized bed reactor, a jet fluidized bed reactor, a moving bed reactor, or a circulating fluidized bed, etc. The carbon formation reactor can operate under any of the conditions such as the temperature, pressure, and residence time described herein. For example, the reaction may occur at a temperature of about 400 °C to about 1000 °C, or about 550 °C to about 900 °C, or about 650 °C to about 800 °C, and the reaction may occur at a pressure of about 1 to 40 bar, about 1 to 20 bar, or about 5 to 15 bar.

[0147] During the reaction, solid carbon may be formed on the catalyst particles, and a layer of solid carbon may be formed. Additional reaction products, such as hydrogen and other products, can be produced as described in more detail with respect to the various embodiments disclosed herein. The reaction products can be processed in any of the systems described herein.

[0148] In some embodiments, the catalyst particles can form a moving bed, e.g., a fluidized bed or a spouted bed in which the particles move relative to each other. For example, at least about 20%, at least about 40%, or at least about 50% of the solid material in the reactor may be fluidized by the gas phase. The relative movement of the catalyst particles can cause attrition of the carbon formed on the catalyst in addition to the catalyst itself. Additionally, the particles can disintegrate by a heterogeneous chemical reaction such as metal dusting (reduction of CO and Boudouard reaction) as schematically shown in FIG. 10. As shown, the fresh catalyst particles 930 can have an initial diameter. Although shown as round or spherical, the catalyst particles can take various shapes, and collectively, the catalyst particles can have an initial average catalyst diameter. The Sauter mean diameter may be used to represent the average diameter of equivalent spherical particles and can be used to understand the fluidization and entrainment of particulate matter. As the reaction progresses, solid carbon can be formed on the catalyst as an outer layer while disintegrating the catalyst. As the catalyst particles move relative to each other, attrition of the catalyst and solid carbon can occur. This process is schematically shown, and small catalyst particulate matter 938 and solid carbon particulate matter 936 are removed from the outer surface of the catalyst particles 932 through disintegration and attrition. The overall process can result in a decrease in the average diameter of the catalyst particles as demonstrated by the catalyst particle diameter being smaller for the catalyst particles 932 than for the initial catalyst particles 930. As the process continues, the catalyst particles may ultimately have a reduced diameter that reaches a certain minimum size, at which point the catalyst particles 934 may be considered consumed.

[0149] Returning to FIG. 9, the relative size differences between catalyst particles when disintegration and attrition occur and particulate matter is removed from the catalyst particles can be used to selectively remove solid product from the reactor using feed and product gas flow rates to fluidize and entrain the product particulate matter. The solid product can be removed continuously or in a semi-batch or batch process. For example, the gas velocity through the reactor can be periodically increased to remove solid particulate matter in a batch or semi-batch mode, or the gas flow rate can be selected with the reactor geometry to have a continuously entrained stream of particulate matter of the desired size. Although not shown, a solid outlet may also be present in the reactor to remove solid product and / or a portion of the catalyst particles from the lower portion of the reactor.

[0150] In addition to the gas phase flow rate, the density of the solid carbon and catalyst particulate matter and the geometry of the carbon formation reactor can be used to selectively remove particulate matter having an average diameter below a certain size from the carbon formation reactor. In some embodiments, the inner diameter of the reactor can be increased above the layer of particulate matter (i.e., the freeboard) to provide a lower gas velocity and allow larger particles to settle on the upper surface of the layer. In some embodiments, the carbon formation reactor can have a conical or increasing diameter towards the upper end of the reactor. In some embodiments, the inner diameter of the carbon formation reactor 900 can increase to a final diameter and then maintain the diameter to the upper end of the vessel. The shape and rate of the inner diameter expansion can be selected to provide the desired residence time of the solid particles entrained in the gas phase and enable proper size selection of the particles 912 remaining in the gas phase and removed from the carbon formation reactor in stream 910.

[0151] The ability to remove particulate matter can be enabled by differences in the size and density of particles resulting from heterogeneous chemical reactions and natural abrasion of the solid product and a portion of the catalyst material where the solid product and the catalyst material move relative to each other, allowing them to be removed from the carbon formation reactor. In some embodiments, the entrained solids in product stream 910 can have an outer mean diameter that is about one-half or less of the outer mean diameter of the solid catalyst particles in the carbon formation reactor. For example, the catalyst entering carbon formation reactor 900 in solid stream 904 can have an outer mean diameter of about 50 - 500 μm, or about 100 - 300 μm. The solid phase, including the catalyst and solid carbon on the catalyst particles within the carbon formation reactor, can have an outer mean diameter of about 20 - 400 μm, or about 50 - 250 μm. The solid particulate matter, including solid carbon particulate matter and / or solid catalyst particulate matter resulting from chemical disintegration or abrasion of the catalyst and solid carbon on the catalyst, can have an outer mean diameter of about 0.01 μm - 100 μm, or about 0.1 μm - about 1 μm.

[0152] The relative amount of carbon removed in the particulate matter stream can be greater than the amount of catalyst removed. For example, the process may result in the solid phase being removed from the carbon formation reactor as an entrained stream, and the solid phase can include solid carbon particulate matter and solid catalyst particulate matter. The solid phase removed from the reactor can be greater than about 50 wt% carbon, or greater than about 80 wt% carbon. Within the reactor, the solid phase includes solid carbon particulate matter and solid catalyst particulate matter, and the solid catalyst particles have carbon formed thereon during the reaction. The solid phase within the reactor can include less than about 50 wt% carbon, less than about 30 wt% carbon, or less than about 20 wt% carbon.

[0153] ​Once removed from the carbon formation reactor 900 in the product stream 910, the entrained solids 912 can be separated using any of the separation devices described herein, such as a cyclone, a backhouse, or a filter. The resulting solid stream from the separator can then be further processed. It is contemplated that any amount of solids in the solid stream can include a catalyst material, and it may be useful to recycle or return at least a portion of the catalyst material into the carbon formation reactor 900 to enable further production of solid carbon. To return the solid catalyst, at least a portion of the solids leaving the carbon formation reactor 900 may be separated and returned to the carbon formation reactor 900 as part of the solid stream 904 and / or as a separate solid inlet stream into the carbon formation reactor.

[0154] Size selection can be used to provide that portion of the separated solids that is returned to or recycled into the carbon formation reactor. In some embodiments, that portion returned to the carbon formation reactor can have a larger Sauter mean diameter than the remainder of the solids in the product stream leaving the carbon formation reactor. For example, that portion of the solid product returned to the carbon formation reactor can be the largest 10%, largest 20%, or largest 30% of the solids removed from the carbon formation reactor as measured by the average Sauter mean diameter of the solids in the product stream. The larger particles can also be a portion of the solids having a higher mass percentage of catalyst. In some embodiments, that portion of the solid stream returned to or recycled into the carbon formation reactor can have a higher catalyst-to-carbon mass ratio than the remainder of the solid product stream.

[0155] The carbon production reactor 900 can be used to perform any of the carbon production reactions described herein. In some embodiments, the carbon production reactor 900 can be used to react a feed stream containing hydrogen and carbon monoxide to produce a solid carbon product stream in addition to a gaseous product containing hydrogen, carbon monoxide, and carbon dioxide. The solid phase can be present in the reactor during the reaction, and the reactor includes a solid catalyst on which the solid carbon product is formed. In some embodiments, the catalyst can form a fluidized bed. Any of the catalysts described herein can be used, and in some embodiments, the catalyst can include iron, iron oxide, or iron carbide (e.g., Fe3C). The solid phase containing the solid catalyst and solid carbon can have less than about 50 wt% carbon. The movement of the solids in the fluidized bed can result in the formation of separate particulate matter of carbon and the solid catalyst. The particulate matter can be entrained in the gas phase leaving the carbon production reactor. The solids leaving the carbon production reactor can be at least about 50 wt% carbon and / or the solids can have an outer mean diameter that is at least about 50% smaller than the solid phase particles in the fluidized bed that are not entrained in the gas phase.

Example

[0156] While the present disclosure has been generally described, the following examples are provided as specific embodiments of the present disclosure and to demonstrate its implementation and advantages. It is understood that the examples are provided by way of illustration and are not intended to limit the specification or the claims in any way.

[0157] Example 1 Conversion of CO and H2 over an Fe catalyst In certain embodiments, as schematically shown in FIG. 11, a fixed bed packed with an Fe catalyst on quartz wool is operated at 650° C. for 10 hours to produce C, CO2, and H2O from CO and H2 reactants. FIG. 12 shows the experimental setup during execution, with carbon deposited on the catalyst portion. The CO conversion is greater than 50%, and the final weight ratio of C to Fe is 10. As shown in FIG. 13, carbon generally deposits at the beginning of the catalyst charge.

[0158] Although various systems, processes, and compositions have been described, certain aspects can include, but are not limited to, the following.

[0159] A first aspect is a process for the reaction of hydrocarbons, comprising reacting hydrocarbons with oxygen in a reactor to produce a gas stream and a solid stream, wherein the gas stream contains hydrogen, water, and carbon oxides, and the solid stream contains solid carbon; and separating the gas stream from the solid stream.

[0160] A second aspect can include the process of the first aspect, wherein the step of reacting the hydrocarbons with the oxygen to produce the gas stream and the solid stream is carried out autothermally or substantially autothermally.

[0161] A third aspect further includes the step of separating water and hydrogen from the gas stream to produce a second gas stream containing the carbon oxides; and recycling the second gas stream back to the reactor.

[0162] A fourth aspect can include any one of the processes of the first to third aspects, wherein the hydrocarbons are light alkanes, coal, biomass, alcohols, naphtha, crude oil, or any combination thereof.

[0163] The fifth aspect is a process of introducing carbon dioxide into the reactor, and further includes the step of reacting at least a part of the carbon dioxide with the hydrocarbon, the oxygen, the hydrogen, the water, the carbon monoxide, or any combination thereof, and can include any one of the processes of the first to fourth aspects.

[0164] The sixth aspect can include any one of the processes of the first to fifth aspects, where the step of reacting includes the step of using a solid catalyst in the reactor.

[0165] The seventh aspect can include the process of the sixth aspect, where the solid catalyst includes elements of Group VI, Group VII, Group VIII, Group IX, or Group X, actinides, lanthanides, their oxides, their alloys, or combinations thereof.

[0166] The eighth aspect can include the process of the sixth or seventh aspect, and further includes the step of generating the solid carbon on the solid catalyst, where the solid stream further includes at least a part of the solid catalyst.

[0167] The ninth aspect can include any one of the processes of the first to eighth aspects, where at least a part of the oxygen is converted to water in the step of reacting, and the water is removed from the process.

[0168] The tenth aspect can include any one of the processes of the first to ninth aspects without carbon dioxide emission.

[0169] In a 11th aspect, a process for the reaction of hydrocarbons comprises reacting a first portion of a first hydrocarbon with one or more oxygen-containing species in a first reactor to produce a first product stream comprising a first portion of hydrogen, water, and carbon oxides; separating the water from the first product stream; separating carbon dioxide from the first product stream and recycling it to the first reactor; reacting the remaining first product stream in a second reactor with a second portion of a second hydrocarbon to produce solid carbon, hydrogen, water, and carbon oxides; separating the solid carbon from the second gas product stream; separating the water from the second gas product stream; separating the hydrogen from the second gas product stream and recycling the remaining second gas product stream to the first reactor.

[0170] A 12th aspect can include the process of the 11th aspect, wherein the first portion of the first hydrocarbon and the second portion of the second hydrocarbon have the same composition.

[0171] A 13th aspect can include the process of the 11th or 12th aspect, wherein the first portion of the first hydrocarbon and the second portion of the second hydrocarbon have different compositions.

[0172] A 14th aspect can include the process of any one of the 11th to 13th aspects, wherein the step of reacting the first portion of the first hydrocarbon with the one or more oxygen-containing species in the first reactor includes reacting the first portion of the first hydrocarbon with carbon dioxide to produce carbon monoxide and hydrogen.

[0173] A 15th aspect can include the process of the 14th aspect, wherein the step of reacting the first portion of the first hydrocarbon is carried out in the substantial absence of water.

[0174] The 16th aspect can include any one of the processes of the 11th to 13th aspects, wherein the step of reacting the first portion of the first hydrocarbon with the one or more oxygen-containing species in the first reactor includes a step of reacting the first portion of the first hydrocarbon with water to produce carbon monoxide and hydrogen.

[0175] The 17th aspect can include any one of the processes of the 11th to 16th aspects, wherein the step of reacting the first portion of the first hydrocarbon with the one or more oxygen-containing species in the first reactor includes a step of introducing oxygen into the first reactor together with the first portion of the first hydrocarbon.

[0176] The 18th aspect can include any one of the processes of the 11th to 17th aspects, further comprising a step of separating at least a portion of the first portion of hydrogen from the stream prior to the step of reacting the first reactor product stream with the second portion of the second hydrocarbon.

[0177] The 19th aspect can include any one of the processes of the 11th to 18th aspects, wherein the step of reacting the first reactor product stream with the second portion of the second hydrocarbon further produces carbon dioxide, and the process further includes a step of separating at least a portion of the second portion of hydrogen from the carbon dioxide.

[0178] The 20th aspect is that the step of reacting the first reactor product stream with the second portion of the second hydrocarbon is carried out in the presence of a solid catalyst, and can include any one of the processes of the 11th to 19th aspects. The 21st aspect can include the process of the 20th aspect, wherein the solid catalyst includes an element of Group VI, Group VII, Group VIII, Group IX, or Group X, actinide, lanthanide, oxides thereof, alloys thereof, or combinations thereof.

[0179] The 21st aspect can include the process of the 20th aspect, wherein the solid catalyst includes an element of Group VI, Group VII, Group VIII, Group IX, or Group X, actinide, lanthanide, oxides thereof, alloys thereof, or combinations thereof.

[0180] The 22nd aspect can include any one of the processes of the 11th to 21st aspects, wherein the step of reacting in the first reactor is carried out autothermally or substantially autothermally.

[0181] The 23rd aspect can include any one of the processes of the 11th to 21st aspects, wherein the step of reacting in the second reactor is carried out autothermally or substantially autothermally.

[0182] The 24th aspect can include any one of the processes of the 11th to 23rd aspects, wherein the step of reacting the first reactor product stream with the second portion of the second hydrocarbon produces a product gas stream containing hydrogen, carbon monoxide, and water, and the process further includes a step of reacting the product gas stream in a water gas shift reactor to convert at least a portion of the carbon monoxide and water to carbon dioxide and hydrogen.

[0183] The 25th aspect can include any one of the processes of the 11th to 24th aspects, wherein the first portion of the hydrocarbon, the second portion of the hydrocarbon, or both include light alkanes, coal, biomass, alcohols, naphtha, crude oil, or any combination thereof.

[0184] The 26th aspect can include the process of the 11th aspect, wherein the first hydrocarbon includes methane, the one or more oxygen-containing species include carbon dioxide, the step of reacting the first reactor product stream in the second reactor includes a step of reacting the carbon monoxide in the second reactor, the step of reacting the carbon oxide with the second portion of the second hydrocarbon in the second reactor is carried out in the presence of a solid catalyst containing iron, and a solid product stream containing solid carbon is produced, and the solid product stream further includes iron and iron carbide.

[0185] Aspect 27 can include the process of Aspect 11, wherein the first hydrocarbon contains biomass, the one or more oxygen-containing species contain oxygen, the step of reacting the first reactor product stream in the second reactor includes the step of reacting carbon monoxide in the second reactor, the step of reacting the carbon oxide with the second portion of the second hydrocarbon in the second reactor is carried out in the presence of a solid catalyst containing iron, and a solid product stream containing solid carbon is produced, and the solid product stream further contains iron and iron carbide.

[0186] In aspect 28, the process includes the steps of reacting carbon dioxide with hydrogen to produce a first product stream containing carbon dioxide, carbon monoxide, and water; separating the carbon monoxide and water from the first product stream; and reacting the carbon monoxide with a portion of a hydrocarbon in a carbon formation reactor to produce a second product stream and a solid product stream, wherein the solid product stream contains solid carbon.

[0187] Aspect 29 can include the process of Aspect 28, wherein the step of reacting the carbon dioxide with the hydrogen is carried out in a reverse water gas shift reactor, and the process further includes the step of recycling the carbon dioxide and hydrogen from the first product stream to the reverse water gas shift reactor.

[0188] The 30th aspect can include the process of the 28th or 29th aspect, wherein the second product stream includes water, carbon monoxide, carbon dioxide, and hydrogen, and the process further includes: separating the water from the second product stream to produce a third product stream; separating the carbon monoxide and hydrogen from the third product stream; recycling at least a portion of the hydrogen from the third product stream to the reverse water gas shift reactor; recycling the carbon monoxide and any hydrocarbons to the carbon formation reactor; and recycling the carbon dioxide from the second product stream to the reverse water gas shift reactor.

[0189] The 31st aspect can include the process of any one of the 28th to 30th aspects, further including introducing oxygen into the carbon formation reactor together with the portion of the carbon monoxide and the hydrocarbons.

[0190] The 32nd aspect can include the process of any one of the 28th to 31st aspects, wherein the step of reacting the carbon monoxide with the portion of the hydrocarbons in the carbon formation reactor is carried out in the presence of a solid catalyst.

[0191] The 33rd aspect can include the process of the 32nd aspect, wherein the solid catalyst includes elements of Group VI, Group VII, Group VIII, Group IX, or Group X, actinides, lanthanides, oxides thereof, alloys thereof, or combinations thereof.

[0192] The 34th aspect can include the process of any one of the 28th to 33rd aspects, wherein the step of reacting the carbon monoxide with the portion of the hydrocarbons in the carbon formation reactor is carried out autothermally or substantially autothermally.

[0193] The 35th aspect can include the process of any one of the 28th to 34th aspects, further comprising the step of cooling the second product stream before leaving the carbon production reactor; and the step of reacting the water and the carbon monoxide in the second product stream in an aqueous gas shift reactor.

[0194] The 36th aspect can include the process of any one of the 28th to 35th aspects, wherein the portion of the hydrocarbon comprises light alkanes, coal, biomass, alcohol, naphtha, crude oil, or any combination thereof.

[0195] In the 37th aspect, the process for the reaction of carbon dioxide comprises the steps of electrolyzing carbon dioxide in an electrolytic cell to produce a product stream containing carbon dioxide, carbon monoxide, and oxygen; separating the carbon dioxide from the product stream; recycling the carbon dioxide to the electrolytic cell; reacting the carbon monoxide with a portion of the hydrocarbon in a carbon production reactor; and producing a second product stream and a solid product stream from the carbon production reactor, wherein the solid product stream contains solid carbon.

[0196] The 38th aspect is such that the second product stream contains water, carbon dioxide, carbon monoxide, and hydrogen, and the process further comprises the steps of separating the water, the carbon dioxide, and the hydrogen from the second product stream; and recycling the carbon monoxide and the hydrocarbon to the carbon production reactor from the second product stream. The 38th aspect can include the process of the 37th aspect.

[0197] The 39th aspect can include the process of the 37th or 38th aspect, further comprising the step of introducing oxygen into the carbon production reactor.

[0198] Aspect 40 can include any one of the processes of Aspects 37 to 39, wherein the step of reacting the carbon monoxide with the portion of the hydrocarbon in the carbon production reactor is carried out in the presence of a solid catalyst.

[0199] Aspect 41 can include the process of Aspect 40, wherein the solid catalyst includes an element of Group VI, Group VII, Group VIII, Group IX, or Group X, actinide, lanthanide, oxides thereof, alloys thereof, or combinations thereof.

[0200] Aspect 42 can include any one of the processes of Aspects 37 to 41, wherein the step of reacting the carbon monoxide with the portion of the hydrocarbon in the carbon production reactor is carried out autothermally or substantially autothermally.

[0201] Aspect 43 can include any one of the processes of Aspects 37 to 42, further including the step of cooling the second product stream leaving the carbon production reactor; and the step of reacting the water and the carbon monoxide in the second product stream in a water gas shift reactor.

[0202] Aspect 44 can include any one of the processes of Aspects 37 to 43, wherein the portion of the hydrocarbon includes light alkanes, coal, biomass, alcohols, naphtha, crude oil, or any combination thereof.

[0203] In Aspect 45, a process for the reaction of a hydrocarbon includes the steps of reacting the hydrocarbon with one or more oxygen-containing species in a first reactor to produce a first product stream containing hydrogen, water, and carbon oxides; separating water from the first product stream; reacting the hydrogen and carbon oxides in a second reactor to produce a second product stream of solid carbon, water, hydrogen, and carbon oxides; separating the solid carbon from the hydrogen, water, and carbon oxides; and separating the water from the hydrogen and carbon oxides.

[0204] Aspect 46 can include the process of Aspect 45, wherein the carbon oxide includes carbon monoxide and carbon dioxide, and the process further includes separating hydrogen from the second product stream to produce a third product stream that is mostly carbon oxide; and recycling the third product stream, which is mostly carbon oxide, to the first reactor to react with the hydrocarbon.

[0205] Aspect 47 can include the process of Aspect 45 or 46, wherein carbon monoxide is separated from the second product stream; and the carbon monoxide is recycled to the second reactor.

[0206] Aspect 48 can include the process of any one of Aspects 45 to 47, wherein hydrocarbon is present in at least one of the first product stream, the second product stream, or the third product stream, and the process further includes separating the hydrocarbon and recycling the hydrocarbon to the first reactor, the second reactor, or both.

[0207] Aspect 49 can include the process of any one of Aspects 45 to 48, wherein the step of reacting the hydrocarbon with the one or more oxygen-containing species in the first reactor includes reacting the hydrocarbon with carbon dioxide.

[0208] Aspect 50 can include the process of Aspect 49, wherein the step of reacting the hydrocarbon is carried out in the substantial absence of water.

[0209] Aspect 51 can include the process of any one of Aspects 45 to 48, wherein the step of reacting the first portion of the first hydrocarbon with the one or more oxygen-containing species in the first reactor includes reacting the hydrocarbon with water to produce carbon monoxide and hydrogen.

[0210] Aspect 52 can include the process of any one of Aspects 45 to 51, wherein the step of reacting the hydrocarbon with the one or more oxygen-containing species in the first reactor includes introducing oxygen into the first reactor together with the hydrocarbon.

[0211] Aspect 53 can include the process of any one of Aspects 45 to 52, further comprising separating at least a portion of hydrogen from the first product stream prior to the step of reacting the carbon monoxide in the second reactor.

[0212] Aspect 54 can include the process of any one of Aspects 45 to 53, further comprising dividing a portion of the second reactor product and recycling them to the second reactor.

[0213] Aspect 55 can include the process of any one of Aspects 45 to 54, wherein the step of reacting the first product stream in the second reactor is carried out in the presence of a solid catalyst.

[0214] Aspect 56 can include the process of Aspect 55, wherein the solid catalyst includes elements of Group VI, Group VII, Group VIII, Group IX, or Group X, actinides, lanthanides, carbon, their oxides, their alloys, or combinations thereof.

[0215] Aspect 57 can include the process of any one of Aspects 45 to 56, wherein the step of reacting in the second reactor is carried out autothermally or exothermally.

[0216] Aspect 58 can include the process of any one of Aspects 45 to 57, wherein the step of reacting the carbon monoxide in the second reactor produces a product gas stream containing hydrogen, carbon monoxide, and water, and the process further includes a step of reacting the product gas stream in an aqueous gas shift reactor to convert at least a portion of the carbon monoxide and water into carbon dioxide and hydrogen.

[0217] Aspect 59 can include the process of any one of Aspects 45 to 58, wherein the step of reacting the carbon monoxide in the second reactor produces a product gas stream containing hydrogen, carbon monoxide, and water, and the process further includes a step of reacting the product gas stream in a reverse aqueous gas shift reactor to convert at least a portion of the carbon dioxide and hydrogen into carbon monoxide and water.

[0218] Aspect 60 can include the process of any one of Aspects 45 to 59, wherein the hydrocarbon includes light alkanes, coal, biomass, alcohol, naphtha, crude oil, or any combination thereof.

[0219] Aspect 61 can include the process of Aspect 45, wherein the hydrocarbon includes methane, the one or more oxygen-containing species include oxygen and carbon dioxide, the carbon monoxide includes carbon monoxide and carbon dioxide, the step of reacting the carbon monoxide in the second reactor is carried out in the presence of a solid catalyst containing iron, and a solid product stream containing solid carbon is produced, and the solid product stream further includes iron oxide, iron, and iron carbide.

[0220] Aspect 62 can include the process of Aspect 45, wherein the hydrocarbon includes biomass, the one or more oxygen-containing species include oxygen and carbon dioxide, the carbon oxide includes carbon monoxide and carbon dioxide, the step of reacting the carbon oxide in the second reactor is carried out in the presence of a solid catalyst containing iron, and a solid product stream containing the solid carbon is produced, and the solid product stream further includes iron oxide, iron, and iron carbide.

[0221] Aspect 63 can include any one of the processes of Aspects 45 to 62 without carbon dioxide emission.

[0222] In Aspect 64, the reaction process for producing hydrogen and carbon includes the steps of introducing a feed stream containing hydrocarbons and an oxidant into a reactor system, wherein the reactor system includes one or more reactors; producing H2 and solid carbon as products in the reactor system; separating the solid carbon and the H2 from the one or more reactors; and recycling any unreacted hydrocarbons and at least a portion of the oxidant to the inlet of the reactor system.

[0223] Aspect 65 can include the process of Aspect 64, wherein at least one of the one or more reactors includes a catalyst.

[0224] Aspect 66 can include the process of Aspect 65, wherein the step of producing the solid carbon catalytically produces the solid carbon using the catalyst.

[0225] Aspect 67 can include the process of Aspect 65 or 56, further including the steps of continuously adding the catalyst to the reactor system; and continuously removing the solid carbon from the reactor system, wherein the solid carbon is disposed on a portion of the catalyst.

[0226] Aspect 68 can include any one of the processes of Aspects 64 to 67, further including a step of producing water as a product in the reaction system, wherein the oxidized substance leaves the reactor system as water.

[0227] Aspect 69 can include any one of the processes of Aspects 64 to 68, wherein the outlet stream from the reactor system is free of or substantially free of carbon dioxide.

[0228] Aspect 70 can include any one of the processes of Aspects 64 to 69, wherein the oxidized substance includes at least one of CO2, CO, O2, or H2O.

[0229] Aspect 71 can include any one of the processes of Aspects 64 to 70, wherein the hydrocarbon includes methane, ethane, natural gas, alcohol, crude oil, biomass, naphtha, or solid hydrocarbon. process.

[0230] Aspect 72 can include any one of the processes of Aspects 64 to 71, wherein the reactor system operates autothermally or exothermally.

[0231] Aspect 73 can include any one of the processes of Aspects 64 to 72, wherein the reactor system includes a catalyst, the catalyst includes iron, the oxidized substance includes O2, H2O, and CO2, and the hydrocarbon includes methane.

[0232] Aspect 74 can include any one of the processes of Aspects 64 to 73, further including a step of separating at least a portion of the oxidized substance in the product stream and a portion of any unreacted hydrocarbon; and a step of recycling the portion of the oxidized substance and the portion of any unreacted hydrocarbon to the inlet of the reactor system.

[0233] In a 75th aspect, a system for producing hydrogen and carbon includes one or more reactors; a feed stream containing hydrocarbons; an oxidant; a solid carbon product; and a hydrogen gas product, wherein the reactor is configured to receive the feed stream and the oxidant and to react the hydrocarbons and the oxidant to produce the solid carbon product and the hydrogen gas product.

[0234] A 76th aspect can include the system of the 75th aspect, wherein at least one of the one or more reactors includes a catalyst.

[0235] A 77th aspect can include the system of the 75th or 76th aspect, further including a water product, wherein the system is configured to convert the oxidant into water.

[0236] A 78th aspect can include any one of the systems of the 75th to 77th aspects, wherein the oxidant includes at least one of CO2, CO, O2, or H2O.

[0237] A 79th aspect can include any one of the systems of the 75th to 78th aspects, wherein the hydrocarbons include methane, ethane, natural gas, alcohol, crude oil, biomass, naphtha, or solid hydrocarbons.

[0238] A 80th aspect can include any one of the systems of the 75th to 79th aspects, wherein the one or more reactors are configured to operate autothermally or exothermally.

[0239] A 81st aspect can include any one of the systems of the 75th to 80th aspects, wherein the one or more reactors include a catalyst, the catalyst includes iron, the oxidant includes O2, H2O, and CO2, and the hydrocarbons include methane.

[0240] Aspect 82 can include any one of the systems of Aspects 75 - 81, further including a recycle system including a separator and a recycle line, wherein the separator is configured to separate at least a portion of the oxidized species and a portion of any unreacted hydrocarbons in a product stream, and to recycle the portion of the oxidized species and the portion of any unreacted hydrocarbons to an inlet of the one or more reactors.

[0241] In aspect 83, a process for the reaction of carbon monoxide and hydrogen comprises reacting a feed stream in contact with a solid phase containing a catalyst and carbon in a reactor to produce a product stream containing hydrogen, carbon monoxide, carbon dioxide, water, and solid carbon, wherein the feed stream contains carbon monoxide and hydrogen, the step; separating a solid stream containing the catalyst and carbon from the product stream to produce a gas stream containing hydrogen, carbon monoxide, carbon dioxide, and water; cooling the gas stream in a heat exchanger; and separating water from the gas stream after the cooling step to produce a dehydrated stream containing hydrogen, carbon monoxide, and carbon dioxide.

[0242] Aspect 84 can include the process of aspect 83, in which carbon dioxide is separated from the dehydrated stream to produce a separated stream containing hydrogen and carbon monoxide.

[0243] Aspect 85 can include the process of aspect 83 or 84, wherein the feed stream further contains hydrocarbons.

[0244] Aspect 86 can include any one of the processes of aspects 83 - 85, wherein the feed stream further contains carbon dioxide.

[0245] Aspect 87 can include the process of any one of Aspects 83 to 86, in which a catalyst stream containing a catalyst is added to the reactor.

[0246] Aspect 88 can include the process of any one of Aspects 83 to 87, in which a part of the solid phase in the reactor is removed from the reactor mostly by gravity.

[0247] Aspect 89 can include the process of any one of Aspects 83 to 88, in which the feed stream is heated in a heat exchanger prior to the step of reacting in the reactor.

[0248] Aspect 90 can include the process of any one of Aspects 83 to 89, in which the step of cooling the gas stream includes the step of cooling the gas stream using the feed stream in a heat exchanger to recover heat.

[0249] Aspect 91 can include the process of any one of Aspects 84 to 90, in which hydrogen is separated from the separated stream to produce a first stream containing hydrogen and a second stream containing carbon monoxide.

[0250] Aspect 92 can include the process of any one of Aspects 83 to 90, in which hydrogen is separated from the dehydrated stream to produce a first stream containing hydrogen and a second stream containing carbon monoxide and carbon dioxide.

[0251] Aspect 93 can include the process of Aspect 91 or 92, in which a part of the second stream is purged from the process to the atmosphere to prevent the accumulation of inert gas, and the part of the second stream is less than 15% by volume of the second stream.

[0252] Aspect 94 can include any one of the processes of Aspects 83 - 93, wherein any one of the gas stream, the dehydrated stream, or the separated stream has additional solids removed through filtration-based solid separation.

[0253] Aspect 95 can include any one of the processes of Aspects 83 - 94, wherein the gas stream is cooled by a steam boiler, a steam superheater, or another heat exchanger, either before or after being cooled by the heat exchanger.

[0254] Aspect 96 can include any one of the processes of Aspects 84 - 95, wherein a portion of the separated stream, called the recycle stream, is recycled and combined with the feed stream, and the recycle stream is 20% - 95% of the volume of the separated stream in terms of gas volume flow rate.

[0255] Aspect 97 can include any one of the processes of Aspects 84 - 95, wherein a portion of the separated stream, called the recycle stream, is recycled and combined with the feed stream, and the recycle stream is 50% - 90% of the volume of the separated stream in terms of gas volume flow rate.

[0256] Aspect 98 can include any one of the processes of Aspects 83 - 95, wherein a portion of the separated stream, called the recycle stream, is recycled and combined with the feed stream, and the recycle stream is 20% - 95% of the volume of the dehydrated stream in terms of gas volume flow rate.

[0257] Aspect 99 can include any one of the processes of Aspects 83 - 95, wherein a portion of the separated stream, called the recycle stream, is recycled and combined with the feed stream, and the recycle stream is 50% - 90% of the volume of the dehydrated stream in terms of gas volume flow rate.

[0258] Aspect 100 can include any one of the processes of Aspects 83 - 99, wherein the solid catalyst in the reactor comprises iron in metallic form, iron oxide, iron carbide, or any combination thereof.

[0259] Aspect 101 can include any one of the processes of Aspects 83 - 100, wherein the ratio of carbon to catalyst in the solid stream is 5:1 - 50:1 by mass.

[0260] Aspect 102 can include any one of the processes of Aspects 83 - 101, wherein the ratio of carbon to catalyst in the solid stream is 2:1 - 200:1 by mass.

[0261] Aspect 103 can include any one of the processes of Aspects 83 - 102, further comprising a step of cooling the reactor during the step of reacting.

[0262] Aspect 104 can include the process of Aspect 103, wherein the step of cooling the reactor includes a step of cooling the reactor using liquid water, boiling water, or superheated steam.

[0263] Aspect 105 can include the process of Aspect 103, wherein the step of cooling the reactor includes a step of cooling the reactor using an endothermic reforming reaction that converts a hydrocarbon stream containing hydrocarbons into a syngas stream containing carbon monoxide and hydrogen.

[0264] Aspect 106 can include any one of the processes of Aspects 83 to 105, wherein the carbon monoxide conversion in the reactor from the feed stream to the product stream is 20% to 60%.

[0265] Aspect 107 can include any one of the processes of Aspects 83 to 106, wherein the carbon dioxide conversion in the reactor from the feed stream to the product stream is 20% to 70%.

[0266] Aspect 108 can include any one of the processes of Aspects 83 to 107, wherein the hydrogen conversion in the reactor from the feed stream to the product stream is 5% to 30%.

[0267] Aspect 109 can include any one of the processes of Aspects 84 to 108, wherein the amount of hydrocarbon in the feed stream is at least about 10% by volume.

[0268] Aspect 110 can include any one of the processes of Aspects 83 to 109, wherein the volume ratio of hydrogen to carbon monoxide in the feed stream is about 0.25 to about 6.

[0269] Aspect 111 can include any one of the processes of Aspects 83 to 110, wherein the reactor is operated at a temperature of about 650°C to about 800°C.

[0270] Aspect 112 can include any one of the processes of Aspects 83 to 111, wherein the reactor is operated at a temperature of about 500°C to about 900°C.

[0271] Aspect 113 can include any one of the processes of Aspects 83 to 112, wherein the reactor is operated at an absolute pressure of about 5 bar to about 15 bar.

[0272] Aspect 114 can include any one of the processes of Aspects 83 - 113, wherein the reactor is operated at an absolute pressure of about 1 bar to about 40 bar.

[0273] Aspect 115 can include any one of the processes of Aspects 83 - 114, wherein the total conversion of all gaseous species in the reactor from the feed stream to the product stream is about 10% to about 50%, and the molar flow rate of the gas stream is about 90% to about 50% of the molar flow rate for the feed stream.

[0274] Aspect 116 can include any one of the processes of Aspects 83 - 115 that does not involve or substantially does not involve direct CO2 emissions.

[0275] In Aspect 117, a heterogeneous reaction system includes a feed stream containing hydrogen, carbon monoxide, and methane that reacts to form a gas stream containing hydrogen, carbon monoxide, carbon dioxide, and methane; and a solid phase containing carbon and a catalyst.

[0276] Aspect 118 can include the system of Aspect 117, wherein a solid - phase catalyst stream containing a catalyst is added to the reaction system, and a solid - phase product stream containing the catalyst and carbon is removed from the reaction system in a continuous, semi - batch, or batch mode.

[0277] Aspect 119 can include the system of Aspect 118, wherein the product stream is more than 50% carbon by weight.

[0278] Aspect 120 can include any one of the systems of Aspects 117 - 119, wherein the solid phase in the reaction system is less than 50% carbon by weight.

[0279] Aspect 121 can include any one of the systems of Aspects 117 - 120 where the inner hydraulic diameter of the reactor expands in the direction of the gas flow.

[0280] Aspect 122 can include any one of the systems of Aspects 118 - 121 where the product stream is entrained from the system by having an outer mean diameter that is less than or equal to one - half of the outer mean diameter of the solid phase. Aspect 122 can include any one of the systems of Aspects 118 - 121 where the product stream is entrained from the system by having an outer mean diameter that is less than or equal to one - half of the outer mean diameter of the solid phase.

[0281] Aspect 123 can include any one of the systems of Aspects 118 - 122 where a heavier stream containing carbon and catalyst is removed from the system; and the heavier stream has an outer mean diameter that is at least 1.5 times larger than that of the solid phase.

[0282] Aspect 124 can include the system of Aspect 123 where at least a portion of the heavier stream is removed from the system by gravity.

[0283] Aspect 125 can include any one of the systems of Aspects 117 - 124 where at least 50% of the solid phase is fluidized by the feed stream.

[0284] Aspect 126 can include any one of the systems of Aspects 117 - 125 where the outer mean diameter of the solid phase is 10 - 400 μm, or alternatively 25 - 250 μm.

[0285] Aspect 127 can include any one of the systems of Aspects 118 - 126 where the outer mean diameter of the catalyst stream is 50 - 500 μm, or alternatively 100 - 300 μm.

[0286] Aspect 128 can include any one of the systems of Aspects 118 - 127, wherein the Sauter mean diameter of the product stream is from 0.01 to 100 μm, or alternatively from 0.1 to 10 μm.

[0287] Aspect 129 can include any one of the systems of Aspects 117 - 128, wherein the catalyst includes Fe in metallic, oxide, or carbide form.

[0288] Aspect 130 can include any one of the systems of Aspects 117 - 129, wherein the catalyst includes Ni or Co in metallic, oxide, or carbide form.

[0289] Aspect 131 can include any one of the systems of Aspects 117 - 130, wherein the catalyst includes W, V, Mo, Ti, Ni, Ta, Zr, Cr, Hf in metallic, oxide, or carbide form.

[0290] Aspect 132 can include any one of the systems of Aspects 117 - 131, wherein the catalyst is unsupported.

[0291] Aspect 133 can include any one of the systems of Aspects 117 - 132, wherein a portion of the product stream is returned to the system in the catalyst stream.

[0292] Aspect 134 can include the system of Aspect 133, wherein the portion of the product stream returned in the catalyst stream has a Sauter mean diameter greater than that of the remainder of the product stream.

[0293] Aspect 135 can include the system of Aspect 133 or 134, wherein the portion of the product stream returned in the catalyst stream has a higher mass ratio of catalyst to C than the remainder of the product stream.

[0294] Aspect 136 can include any one of the systems of Aspects 117 - 135, where the gas stream also includes water.

[0295] Aspect 137 can include any one of the systems of Aspects 117 - 136, where the temperature of the reactor is 650 - 800 °C, or alternatively 400 - 900 °C.

[0296] Aspect 138 can include any one of the systems of Aspects 117 - 137, where the pressure of the reactor is an absolute pressure of about 1 - 40 bar, or about 1 - 20 bar, or alternatively a standard atmospheric pressure of 5 - 15 bar.

[0297] Aspect 139 can include any one of the systems of Aspects 117 - 138, where the reactor is a fluidized bed or a spouted bed.

[0298] Aspect 140 is configured to form a fluidized bed in the reactor with a solid phase including C, Fe, and Fe3C, where the solid phase has less than 50% C by weight; and the system further includes a solid product stream entrained from the reactor, where the solid product stream includes at least 50% C by weight and has a Sauter mean diameter at least 50% smaller than the solid phase in the reactor. Any one of the systems of Aspects 117 - 139 can be included.

[0299] In Aspect 141, a heterogeneous reaction process includes reacting a feed stream including hydrogen and carbon monoxide to produce a gas stream including hydrogen, carbon monoxide, and carbon dioxide, where the reacting step is performed in the presence of a catalyst in a reactor; and includes a step of generating a solid phase containing carbon on the catalyst.

[0300] The 142nd aspect can include the process of the 141st aspect, further including the step of adding a solid catalyst stream containing a catalyst to the reactor during the step of reacting; and the step of removing a solid product stream containing carbon and catalyst from the reactor in a continuous, semi-batch, or batch mode.

[0301] The 143rd aspect can include the process of the 141st or 142nd aspect, wherein the product stream is carbon in an amount greater than 50% by weight.

[0302] The 144th aspect can include the process of any one of the 141st to 143rd aspects, wherein the solid phase in the reaction system is carbon in an amount less than 50% by weight.

[0303] The 145th aspect can include the process of any one of the 141st to 144th aspects, wherein the inner hydraulic diameter of the reactor increases in the direction of gas flow.

[0304] The 146th aspect can include the process of any one of the 141st to 145th aspects, wherein the product stream is entrained from the system by having an outer mean diameter that is less than or equal to one-half of the outer mean diameter of the solid phase in the reactor.

[0305] The 147th aspect can include the process of any one of the 141st to 146th aspects, wherein a heavier stream containing carbon and catalyst is removed from the system, and the heavier stream has an outer mean diameter that is at least 1.5 times larger than that of the solid phase.

[0306] The 148th aspect can include the process of the 147th aspect, wherein at least a portion of the heavier stream is removed from the system by gravity.

[0307] Aspect 149 can include the process of any one of Aspects 141 to 148, wherein at least 50% of the solid phase in the reactor is fluidized by the feed stream.

[0308] Aspect 150 can include the process of any one of Aspects 141 to 149, wherein the solid phase in the reactor has a Sauter mean diameter of 10 to 400 μm, or alternatively 25 to 250 μm.

[0309] Aspect 151 can include the process of any one of Aspects 141 to 150, wherein the Sauter mean diameter of the catalyst stream is 50 to 500 μm, or alternatively 100 to 300 μm.

[0310] Aspect 152 can include the process of any one of Aspects 141 to 151, wherein the Sauter mean diameter of the product stream is 0.01 to 100 μm, or alternatively 0.1 to 10 μm.

[0311] Aspect 153 can include the process of any one of Aspects 141 to 152, wherein the catalyst contains Fe in the form of metal, oxide, or carbide.

[0312] Aspect 154 can include the process of any one of Aspects 141 to 153, wherein the catalyst contains Ni or Co in the form of metal, oxide, or carbide.

[0313] Aspect 155 can include the process of any one of Aspects 141 to 154, wherein the catalyst contains W, V, Mo, Ti, Ni, Ta, Zr, Cr, Hf in the form of metal, oxide, or carbide.

[0314] Aspect 156 can include the process of any one of Aspects 141 to 155, wherein the catalyst is unsupported.

[0315] Aspect 157 can include the process of any one of Aspects 141 to 156, in which a portion of the product stream is returned to the reactor in the catalyst stream.

[0316] Aspect 158 can include the process of Aspect 157, in which the portion of the product stream returned in the catalyst stream has a larger Sauter mean diameter than the remainder of the product stream.

[0317] Aspect 159 can include the process of Aspect 157 or 158, in which the portion of the product stream returned in the catalyst stream has a higher mass ratio of catalyst to C than the remainder of the product stream.

[0318] Aspect 160 can include the process of any one of Aspects 141 to 159, in which the gas stream also includes methane and water.

[0319] Aspect 161 can include the process of any one of Aspects 141 to 160, in which the temperature of the reactor is 650°C to 800°C, or alternatively 400°C to 900°C.

[0320] Aspect 162 can include the process of any one of Aspects 141 to 161, in which the pressure of the reactor is about 1 to about 40 bar, or an absolute pressure of about 1 to 20 bar, or alternatively a gauge pressure of 5 to 15 bar.

[0321] Aspect 163 can include the process of any one of Aspects 141 to 162, in which the reactor is a fluidized bed or a spouted bed.

[0322] The 164th aspect is configured to generate a fluidized bed in a reactor with a solid phase that is C, Fe, and Fe3C containing less than 50% C by weight; and the system further includes a solid product stream entrained from the reactor, the solid product stream containing at least 50% C by weight and having a Sauter mean diameter at least 50% smaller than the solid phase in the reactor, and can include any one of the processes of the 141st to 163rd aspects.

[0323] It should be further understood that this description is not limited to the specific methodologies, compounds, materials, production techniques, uses, and applications described herein, and these may be modified. It should also be understood that the technical terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the scope of the present system and method. It should be noted that when used in this specification and the appended claims (in this application or any application derived therefrom), the singular forms "a", "an", and "the" include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to "an element" refers to reference to one or more elements and includes equivalents thereof known to those skilled in the art. All conjunctions used should be understood in the broadest possible sense. Thus, the word "or" should be understood as having a logical "or" definition rather than a logical "exclusive or" definition unless the context clearly requires otherwise. It should be understood that the structures described herein also refer to functional equivalents of such structures. Expressions that can be construed as approximate should be understood as such unless the context clearly dictates otherwise.

[0324] Unless defined otherwise, all scientific and technical terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which this description belongs. Although preferred methods, techniques, devices, and materials are described, any methods, techniques, devices, or materials similar or equivalent to those described herein may be used in the practice or testing of the present systems and methods. It should be understood that the structures described herein also refer to functional equivalents of such structures. The present systems and methods are now described in detail with reference to its embodiments shown in the accompanying drawings.

[0325] Upon reading this disclosure, other variations and modifications will be apparent to one of ordinary skill in the art. Such variations and modifications may involve equivalent and other features already known in the art and may be used instead of or in addition to the features already described herein.

[0326] Although claims may be formulated for particular combinations of features in this application or any further application derived therefrom, the scope of the disclosure also includes any novel feature or any novel combination of features or any generalization thereof, whether or not it relates to the same system or method as that currently claimed in any claim, explicitly or implicitly disclosed herein, and whether or not it alleviates any or all of the technical problems. It should be understood to include.

[0327] Features described in the context of separate embodiments may also be provided in combination in a single embodiment. Conversely, for the sake of brevity, the various features described in the context of a single embodiment may also be provided separately or in any suitable partial combination. The applicant hereby notifies that new claims may be formulated for such features and / or combinations of such features during the prosecution of this application or any further application derived therefrom.

Claims

1. A process for reacting a hydrocarbon, said process comprising: reacting the hydrocarbon with oxygen in a reactor to produce a gas stream and a solid stream, said gas stream comprising hydrogen, water, and carbon oxides, and said solid stream comprising solid carbon; and separating said gas stream from said solid stream The process comprising the above.

2. The process according to claim 1, wherein the step of reacting the hydrocarbon with the oxygen to produce the gas stream and the solid stream is carried out autothermally or substantially autothermally.

3. separating water and hydrogen from said gas stream to produce a second gas stream, said second gas stream comprising said carbon oxides; and recycling said second gas stream back to said reactor The process according to claim 1, further comprising the above.

4. The process according to claim 1, wherein the hydrocarbon is a light alkane, coal, biomass, alcohol, naphtha, crude oil, or any combination thereof.

5. introducing carbon dioxide into said reactor, at least a portion of said carbon dioxide being reacted with said hydrocarbon, said oxygen, said hydrogen, said water, said carbon oxides, or any combination thereof The process according to claim 1, further comprising the above.

6. The reacting step comprises using a solid catalyst in said reactor, and said solid catalyst comprises elements of Group VI, Group VII, Group VIII, Group IX, Group X, actinides, lanthanides, oxides thereof, alloys thereof, or combinations thereof. The process according to claim 1.

7. producing said solid carbon on said solid catalyst, said solid stream further comprising at least a portion of said solid catalyst The process according to claim 6, further comprising the above.

8. A process for reacting a hydrocarbon, said process comprising: reacting the hydrocarbon with one or more oxygen-containing species in a first reactor to produce a first product stream comprising hydrogen, water, and carbon oxides; separating water from said first product stream; Reacting the hydrogen and carbon oxides in a second reactor to produce a second product stream of solid carbon, water, hydrogen, and carbon oxides; Separating the solid carbon from the hydrogen, water, and carbon oxides; and Separating the water from the hydrogen and carbon oxides comprise the process.

9. The carbon oxides include carbon monoxide and carbon dioxide, and the process comprises Separating hydrogen from the second product stream to produce a third product stream that is mostly carbon oxides; and Recycling the third product stream, which is mostly carbon oxides, to the first reactor to react with the hydrocarbon further comprise the process according to claim 8.

10. Carbon monoxide is separated from the second product stream; and The carbon monoxide is recycled to the second reactor, the process according to claim 8.

11. Hydrocarbons are present in at least one of the first product stream, the second product stream, or the third product stream, and the process further comprises separating the hydrocarbons and recycling the hydrocarbons to the first reactor, the second reactor, or both, the process according to claim 10.

12. The step of reacting the hydrocarbon with the one or more oxygen-containing species in the first reactor comprises reacting the hydrocarbon with carbon dioxide comprise the process according to claim 8.

13. The step of reacting the hydrocarbon is carried out in the substantial absence of water, the process according to claim 12.

14. The step of reacting the hydrocarbon with the one or more oxygen-containing species in the first reactor comprises reacting the hydrocarbon with water to produce carbon monoxide and hydrogen comprise the process according to claim 8.

15. The step of reacting the hydrocarbon with the one or more oxygen-containing species in the first reactor comprises introducing oxygen into the first reactor together with the hydrocarbon comprise the process according to claim 8.

16. Prior to the step of reacting the carbon oxides in the second reactor, separating at least a portion of the hydrogen from the first product stream further comprise the process according to claim 8.

17. Dividing a portion of the second reactor product and recycling them to the second reactor The process according to claim 8, further comprising

18. The step of reacting the first product stream in the second reactor is carried out in the presence of a solid catalyst, and the solid catalyst comprises elements of Group VI, Group VII, Group VIII, Group IX, Group X, actinides, lanthanides, carbon, oxides thereof, alloys thereof, or combinations thereof. The process according to claim 8.

19. The step of reacting in the second reactor is carried out autothermally or exothermally. The process according to claim 8.

20. The step of reacting the carbon monoxide in the second reactor produces a product gas stream comprising hydrogen, carbon monoxide, and water, and the process reacting the product gas stream in a water gas shift reactor to convert at least a portion of the carbon monoxide and water to carbon dioxide and hydrogen The process according to claim 8, further comprising

21. The step of reacting the carbon monoxide in the second reactor produces a product gas stream comprising hydrogen, carbon monoxide, and water, and the process reacting the product gas stream in a reverse water gas shift reactor to convert at least a portion of the carbon dioxide and hydrogen to carbon monoxide and water The process according to claim 8, further comprising

22. The hydrocarbon comprises light alkanes, coal, biomass, alcohols, naphtha, crude oil, or any combination thereof. The process according to claim 8.

23. The hydrocarbon comprises methane, the one or more oxygen-containing species comprise oxygen, steam, and carbon dioxide, the carbon monoxide comprises carbon monoxide and carbon dioxide, the step of reacting the carbon monoxide in the second reactor is carried out in the presence of a solid catalyst comprising iron, and a solid product stream comprising solid carbon is produced, and the solid product stream further comprises iron oxide, iron, and iron carbide. The process according to claim 8.

24. The hydrocarbon contains biomass, the one or more oxygen-containing species include oxygen, steam, and carbon dioxide, the carbon oxide includes carbon monoxide and carbon dioxide, the step of reacting the carbon oxide in the second reactor is carried out in the presence of a solid catalyst containing iron, and a solid product stream containing the solid carbon is produced, and the solid product stream further includes iron oxide, iron, and iron carbide, the process according to claim 8.

25. A reaction process for producing hydrogen and carbon, wherein the process comprises: introducing a feed stream containing a hydrocarbon and an oxidant into a reactor system, the reactor system including one or more reactors, the step; The step of producing H ２ and solid carbon as products in the reactor system; The step of separating the solid carbon and the H ２ from the one or more reactors; and recycling any unreacted hydrocarbon and at least a portion of the oxidant to the inlet of the reactor system The process comprising.

26. The process according to claim 25, wherein at least one of the one or more reactors contains a catalyst.

27. The process according to claim 25, wherein the step of producing the solid carbon catalytically produces the solid carbon using a catalyst.

28. continuously adding a catalyst to the reactor system; and continuously removing the solid carbon from the reactor system, the step wherein the solid carbon is disposed on a portion of the catalyst The process according to claim 25, further comprising.

29. producing water as a product in the reactor system, the step wherein the oxidant leaves the reactor system as water The process according to claim 25, further comprising.

30. The process according to claim 25, wherein the outlet stream from the reactor system is free or substantially free of carbon dioxide.

31. wherein the oxidized product contains at least one of CO ２ , CO, O ２ , or H ２ O, the process according to claim 25.

32. The hydrocarbon includes methane, ethane, natural gas, alcohol, crude oil, biomass, naphtha , or solid hydrocarbon, the process according to claim 25.

33. The reactor system includes a catalyst, the catalyst includes iron, and the oxidant includes O ２ , H ２ O, and CO ２ , and the hydrocarbon includes methane. The process according to claim 25.

34. separating at least a portion of the oxidant in the product stream and a portion of any unreacted hydrocarbon; and recycling the portion of the oxidant and the portion of any unreacted hydrocarbon to the inlet of the reactor system The process according to claim 25, further comprising.

35. A system for producing hydrogen and carbon, wherein the system comprises: one or more reactors; a feed stream containing hydrocarbons; an oxidant; a solid carbon product; and a hydrogen gas product wherein the reactor is configured to receive the feed stream and the oxidant and to react the hydrocarbons and the oxidant to produce the solid carbon product and the hydrogen gas product. The system. **Claim 36** The system according to claim 35, wherein at least one of the one or more reactors contains a catalyst. **Claim 37** A water product further comprising, wherein the system is configured to convert the oxidant to water. The system according to claim 35. **Claim 38** wherein the oxidized substance is CO ２ , CO, O ２ , or H ２ O, and the system according to claim 35, comprising at least one of them. **Claim 39** The system according to claim 35, wherein the hydrocarbons include methane, ethane, natural gas, alcohol, crude oil, biomass, naphtha, or solid hydrocarbons. **Claim 40** The system according to claim 35, wherein the one or more reactors are configured to operate autothermally or exothermally. **Claim 41** The one or more reactors contain a catalyst, the catalyst contains iron, and the oxidized substance contains O ２ , H ２ O, and CO ２ and the hydrocarbon contains methane, the system according to claim 35. **Claim 42** A recycle system including a separator and a recycle line, wherein the separator is configured to separate at least a portion of the oxidant and a portion of any unreacted hydrocarbons in the product stream and to recycle the portion of the oxidant and the portion of any unreacted hydrocarbons to the inlet of the one or more reactors. The system according to claim 35, further comprising. **Claim 43** A process for reacting carbon monoxide and hydrogen, the process comprising: reacting a feed stream in contact with a solid phase containing a catalyst and carbon in a reactor to produce a product stream containing hydrogen, carbon monoxide, carbon dioxide, water, and solid carbon, wherein the feed stream contains carbon monoxide and hydrogen; separating a solid stream containing the catalyst and carbon from the product stream to produce a gas stream containing hydrogen, carbon monoxide, carbon dioxide, and water; cooling the gas stream in a heat exchanger; and separating water from the gas stream after the cooling step to produce a dehydrated stream containing hydrogen, carbon monoxide, and carbon dioxide The process comprising. **Claim 44** The process according to claim 43, wherein the feed stream further comprises hydrocarbons.

45. The process according to claim 43, wherein the feed stream further comprises carbon dioxide.

46. The process according to claim 43, wherein the feed stream is heated in a heat exchanger prior to the step of reacting in the reactor.

47. The step of cooling the gas stream comprises the step of cooling the gas stream using the feed stream in a heat exchanger to recover heat The process according to claim 43.

48. Carbon dioxide is separated from the dehydrated stream to produce a separated stream containing hydrogen and carbon monoxide, hydrogen is separated from the separated stream to produce a first stream containing hydrogen and a second stream containing carbon monoxide, The process according to claim 43.

49. Hydrogen is separated from the dehydrated stream to produce a first stream containing hydrogen and a second stream containing carbon monoxide and carbon dioxide, The process according to claim 43.

50. A portion of the second stream is purged from the process to the atmosphere to prevent accumulation of inert gas, and the portion of the second stream is less than 15% by volume of the second stream, The process according to claim 48.

51. The process according to claim 43, wherein any of the gas stream, the dehydrated stream, or the separated stream has additional solids removed through filtration-based solid separation.

52. Before or after the gas stream is cooled by the heat exchanger, the gas stream is cooled by a steam boiler, a steam superheater, or another heat exchanger, The process according to claim 43.

53. Carbon dioxide is separated from the dehydrated stream to produce a separated stream containing hydrogen and carbon monoxide, a portion of the separated stream that produces the recycle stream is recycled and combined with the feed stream, and the recycle stream is 20% to 95% by volume of the separated stream in gas volume flow rate, The process according to claim 43.

54. A portion of the dehydrated stream that generates the recycle stream is recycled and combined with the feed stream, and the recycle stream is 20% to 95% of the volume of the dehydrated stream in terms of gas volume flow rate, the process according to claim 43.

55. The process according to claim 43, wherein the solid catalyst in the reactor comprises iron in metallic form, iron oxide, iron carbide, or any combination thereof.

56. The process according to claim 43, wherein the ratio of carbon to catalyst in the solid stream is 2:1 to 200:1 by mass.

57. A step of cooling the reactor during the step of reacting further comprising the process according to claim 43.

58. The process according to claim 57, wherein the step of cooling the reactor comprises a step of cooling the reactor using liquid water, boiling water, or superheated steam.

59. The process according to claim 57, wherein the step of cooling the reactor comprises a step of cooling the reactor using an endothermic reforming reaction that converts a hydrocarbon stream containing hydrocarbons into a syngas stream containing carbon monoxide and hydrogen.

60. The process according to claim 43, wherein the carbon monoxide conversion in the reactor from the feed stream to the product stream is 20% to 60%.

61. The process according to claim 43, wherein the carbon dioxide conversion in the reactor from the feed stream to the product stream is 20% to 70%.

62. The process according to claim 43, wherein the hydrogen conversion in the reactor from the feed stream to the product stream is 5% to 30%.

63. Carbon dioxide is separated from the dehydrated stream to produce a separated stream containing hydrogen and carbon monoxide, and the amount of the hydrocarbon in the feed stream is at least about 10% by volume, the process according to claim 43.

64. The process according to claim 43, wherein the ratio of hydrogen to carbon monoxide in the feed stream by volume is about 0.25 to about 6.

65. The process according to claim 43, wherein the reactor is operated at a temperature of about 400 °C to about 900 °C.

66. The process according to claim 43, wherein the reactor is operated at an absolute pressure of about 1 bar to about 40 bar absolute pressure.

67. The process of claim 43, wherein the total conversion of all gaseous species in the reactor from the feed stream to the product stream is from about 10% to about 50%, and the molar flow rate of the gas stream is from about 90% to about 50% of the molar flow rate for the feed stream.

68. A multiphase reaction process, wherein the process comprises reacting a feed stream comprising hydrogen and carbon monoxide to produce a gas stream comprising hydrogen, carbon monoxide, and carbon dioxide, wherein the reacting step is carried out in a reactor in the presence of a catalyst; and producing a solid phase comprising carbon on the catalyst the process comprising.

69. adding a solid catalyst stream comprising a catalyst to the reactor during the reacting step; and removing a solid product stream comprising carbon and catalyst from the reactor in a continuous, semi-batch, or batch mode the process of claim 68, further comprising.

70. The process of claim 69, wherein the solid product stream is greater than 50% carbon by weight.

71. The process of claim 68, wherein the solid phase in the reactor is less than 50% carbon by weight.

72. The process of claim 68, wherein the inner hydraulic diameter of the reactor increases in the direction of gas flow.

73. The process of claim 69, wherein the product stream is entrained from the system by having an outer mean diameter that is less than or equal to one-half of the outer mean diameter of the solid phase in the reactor.

74. The process of claim 68, wherein a heavier stream comprising carbon and catalyst is removed from the system, and the heavier stream has an outer mean diameter that is at least 1.5 times greater than the solid phase.

75. The process of claim 74, wherein at least a portion of the heavier stream is removed from the system by gravity.

76. The process of claim 68, wherein at least 50% of the solid phase in the reactor is fluidized by the feed stream.

77. The process of claim 68, wherein the solid phase in the reactor has an outer mean diameter of 10 to 400 μm.

78. The process of claim 68, wherein the outer mean diameter of the catalyst stream is 50 to 500 μm.

79. The process according to claim 68, wherein the Sauter mean diameter of the product stream is from 0.01 to 100 μm.

80. The process according to claim 68, wherein the catalyst comprises Fe in metallic, oxide, or carbide form.

81. The process according to claim 68, wherein the catalyst comprises Ni or Co in metallic, oxide, or carbide form.

82. The process according to claim 69, wherein a portion of the product stream is returned to the reactor in the catalyst stream.

83. The process according to claim 82, wherein the portion of the product stream returned in the catalyst stream has a Sauter mean diameter greater than that of the remainder of the product stream.

84. The process according to claim 82, wherein the portion of the product stream returned in the catalyst stream has a higher mass ratio of catalyst to C than the remainder of the product stream.

85. The process according to claim 68, wherein the gas stream also comprises methane and water.

86. The process according to claim 68, wherein the temperature of the reactor is from 400 °C to 900 °C.

87. The process according to claim 68, wherein the pressure of the reactor is from 1 to 40 bar absolute pressure.

88. The process according to claim 68, wherein the reactor is a fluidized bed or a spouted bed.

89. The solid phase is configured to form a fluidized bed in the reactor together with a solid phase comprising C, Fe, and Fe3C that is less than 50% C by weight; and the system further comprises a solid product stream entrained from the reactor, the solid product stream comprising at least 50% C by weight and having a Sauter mean diameter at least 50% smaller than that of the solid phase in the reactor. The process according to claim 68.

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