System, apparatus, and method for controlling the input and output pressures of an air intake engine reformer.

Abstract

Systems and methods are provided for producing end products from hydrocarbon gases, such as flare gas, using partial oxidation. Methods and systems are provided for minimizing the compression work required for an air-breathing engine reformer in a gas-to-liquid system. Methods and systems are provided for minimizing the compression work required for an air-breathing engine reformer in a gas-to-liquid system and method by one or more of: (a) reducing the amount of nitrogen; (b) increasing the engine reformer back pressure from the standard 1 or 2 bar to up to 5 bar; (c) using a turbo expander to recover much of the compression work, thereby reducing, among other things, the cost of operating the plant; and (d) using an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressure. In one embodiment, the end product is methanol.

Description

TECHNICAL FIELD

[0001] This application claims the benefit of the filing date of U.S. Provisional Application No. 63 / 304,463 filed on January 28, 2022 and claims the benefit of its priority right under 35 U.S.C. § 119(e)(1), is a continuation-in-part of U.S. Application No. 17 / 746,942 filed on May 17, 2022, is a continuation-in-part of U.S. Application No. 17 / 953,056 filed on September 26, 2022, is a continuation-in-part of U.S. Application No. 17 / 984,126 filed on November 9, 2022, claims the benefit of the filing date of U.S. Provisional Application No. 63 / 304,371 filed on January 28, 2022 and claims the benefit of its priority right under 35 U.S.C. § 119(e)(1), and claims the benefit of the filing date of U.S. Provisional Application No. 63 / 304,475 filed on January 28, 2022 and claims the benefit of its priority right under 35 U.S.C. § 119(e)(1), the entire disclosure of each of which is incorporated herein by reference in its entirety.

[0002] The present invention relates to new and improved methods, apparatuses and systems for reducing the compressor workload (e.g., compression requirements such as the number and size of compressors, and the energy required to operate the compressors) required for reformer-based hydrocarbon processing systems, such as gas liquefaction systems, including systems for recovering hydrocarbon gases such as flare gas and converting them into useful and economically feasible materials. In particular, the present invention relates to new and improved methods, apparatuses and systems for operating engines, particularly air-breathing reformers, for use in gas liquefaction systems and processes. The terms “flare gas,” “waste gas,” and similar terms are given the broadest possible meaning and shall include gases generated, produced, associated with, or manufactured by or from oil and gas production, hydrocarbon wells (including conventional and unconventional wells), petrochemical processing, refining, landfill, wastewater treatment, dairy farming, livestock production, and other municipal, chemical, and industrial processes. Therefore, for example, flare gas and waste gas shall include stranded gas, associated gas, landfill gas, vent gas, biogas, digester gas, small pocket gas, remote gas, etc. [Background technology]

[0003] Typically, flare gas is a mixture of different gases. Its composition depends on the source of the flare gas. For example, gas released during oil and gas production mainly consists of natural gas. Natural gas is more than 90% methane (CH4), and also contains ethane and small amounts of other hydrocarbons, water, N2, and CO2. Flare gas from refineries and other chemical and manufacturing operations is usually a mixture of hydrocarbons and possibly H2. Landfill gas, biogas, and digester gas are usually a mixture of CH4 and CO2, and also contain small amounts of other inert gases. Generally, flare gas contains one or more of the following gases: methane, ethane, propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, ethylene, propylene, 1-butene, carbon monoxide, carbon dioxide, hydrogen sulfide, hydrogen, oxygen, nitrogen, and water.

[0004] The majority of flare gas originates from smaller, individual point sources, such as numerous oil or gas wells in oil fields, landfills, or chemical plants. Prior to this invention, flare gas, particularly that generated from hydrocarbon production wells and other small point sources, was burned and discarded, and in some cases, may have been directly discharged into the atmosphere. This flare gas could not be economically recovered or utilized. The burning and discharge of flare gas from both hydrocarbon production and other attempts has raised serious concerns regarding pollution and greenhouse gas emissions.

[0005] In this specification, unless otherwise specified, the terms “syngas,” “synthesis gas,” and similar terms should be given the broadest possible meaning, including gases having a mixture of H2 and CO as the main components, and also potentially including CO2, N2, water, and small amounts of other materials.

[0006] In this specification, unless otherwise specified, “product gas” and similar terms should be given the broadest possible meaning, and include gases having H2, CO, and other hydrocarbons, and typically containing substantial amounts of other hydrocarbons such as methane.

[0007] In this specification, unless otherwise specified, the term “reprocessing gas” includes “syngas,” “synthesis gas,” and “product gas.”

[0008] Unless otherwise specified, as used herein, “partial oxidation,” “to partially oxidize,” and similar terms mean a chemical reaction in which a substoichiometric mixture of fuel and air (i.e., a fuel-rich mixture) partially reacts (e.g., burns) to produce synthesis gas. The term partial oxidation generally includes both thermal partial oxidation (TPOX) and catalytic partial oxidation (CPOX), which occur in catalytic reformers. The general formula for a partial oxidation reaction is as follows:

[0009] TIFF0007933880000001.tif17170

[0010] Unless otherwise noted, the ranges of values ​​used herein are intended solely as abbreviations for individually referring to each individual value within that range. Unless otherwise noted herein, each individual value within a range is incorporated herein as if it were individually listed herein.

[0011] Generally, as used herein, the term “approximately” means, unless otherwise specified, to include a variance or range of ±10%, or the greater of the experimental error or instrumental error associated with obtaining the stated value.

[0012] Unless otherwise noted, the term "CO2e" is used here to define the equivalence of other, more influential greenhouse gases (e.g., methane and nitrous oxide) to carbon dioxide on a 20-year or 100-year global warming potential basis, based on the methodology of the Intergovernmental Panel on Climate Change (IPCC) Fifth Assessment Report (AR5). The term "carbon intensity" refers to the lifecycle CO2e generated per unit mass of the product.

[0013] In this specification, unless otherwise specified, the term “crude methanol” is defined as methanol produced in the methanol synthesis loop before the removal of water, dissolved gases, and other contaminants. Crude methanol often contains 5–20 wt% water, dissolved gases (e.g., 1–2 wt% CO2), and trace contaminants (e.g., ethanol). In this specification, unless otherwise specified, the term “stabilized methanol” is defined as crude methanol that has undergone a flashing operation (e.g., a single-stage flash drum) to reduce the concentrations of dissolved gases and other light components. In many cases, the CO2 concentration of stabilized methanol is less than 1%, most commonly around 0.5 wt%. In this specification, terms such as “raw material methanol” and “initial methanol” refer to “crude methanol,” “stabilized methanol,” or both. In this specification, the term “grade methanol” is defined as methanol that meets purity standards such as the ASTM AA standard (D1152) or the IMPCA methanol reference standard.

[0014] In this specification, unless otherwise specified, the terms % and mol% are used interchangeably and refer, for example, to the ratio of the number of moles of the first component to the total number of moles of the formulation, mixture, material, or product.

[0015] In this specification, unless otherwise specified, the terms wt% (abbreviation: wt%) and mass% refer to the percentage of the weight of the first component relative to the total weight of, for example, a formulation, mixture, material, or product.

[0016] In this specification, unless otherwise specified, room temperature is 25°C, and standard temperature and standard pressure are 15°C and 1 atmosphere (1.01325 bar). Unless explicitly stated otherwise, all tests, test results, physical properties, and values ​​for temperature dependence, pressure dependence, or both are provided at standard temperature and standard pressure.

[0017] Where used herein, unless otherwise specified, “fuel-to-air equivalent ratio,” “equivalent ratio,” “fuel / air equivalent ratio,” “Φ,” or “ER,” and similar terms are synonymous and given their broadest meaning, and include the ratio of the actual fuel / air ratio to the stoichiometric fuel / air ratio. The stoichiometric air-fuel ratio is the air-fuel ratio required for ideal stoichiometric combustion to occur, in which all fuel and oxygen are consumed in the reaction, and the products are carbon dioxide and water. Global warming and environmental problems

[0018] Figure 12 shows the relative environmental impact of exhaust gas emissions compared to carbon dioxide emissions, which are already a serious problem.

[0019] The impact of methane leaks from flare gases and vents on global warming cannot be underestimated. According to a 2019 report by the International Energy Agency (IEA), approximately 200 billion cubic meters of waste gas and flare gas were burned or released into the atmosphere in 2018. Approximately 50 billion cubic meters of gas were released, and approximately 150 billion cubic meters of gas were burned in flares. The combustion aims to convert hydrocarbons into carbon dioxide, but its peak efficiency is 98%, and efficiency decreases in the presence of wind. The combination of low combustion efficiency and gas release resulted in a total emission of approximately 1.4 billion tons of CO2e in CO2e equivalent. This accounts for approximately 2.7% of the total annual anthropogenic CO2e emissions.

[0020] The background art section of this invention is intended to introduce various aspects of the technology that may be relevant to embodiments of this invention. Therefore, the preceding discussion in this section provides a framework for understanding the invention and should not be considered an endorsement of prior art. [Overview of the project] [Problems that the invention aims to solve]

[0021] The need for systems, apparatus, and methods for converting uneconomical hydrocarbon fuels (e.g., stranded gas, associated gas, unassociated gas, landfill gas, flare gas, small pocket gas, remote gas, wastewater treatment gas) into value-added, easily transportable products (e.g., methanol, ethanol, ammonia, dimethyl ether, FT liquids, and other fuels or chemicals) has grown over the years but remains unmet. In systems, apparatus, and methods for converting uneconomical hydrocarbon fuels into value-added, easily transportable products, when air-intake engines and their operation are used as reformers, and when these engines are operated under rich conditions, there has been a continued need for improved systems and methods for controlling engine operation, particularly inlet and outlet pressures and pressure differences. The present invention addresses these needs, in particular, by providing the products, apparatus, and processes taught and disclosed herein.

[0022] In general, there are significant problems, costs, and inefficiencies associated with the compression work used in some embodiments of gas liquefaction systems. This is because the pressure required in the synthesis process is usually much higher than the pressure at the outlet of the engine reformer. For example, in the case of methanol synthesis, the pressure required at the inlet to the methanol production apparatus is usually 50 bar, while the pressure at the outlet of a commercial engine is usually around 1 bar (the outlet or output of the engine is used, for example, to feed an intermediate to a methanol synthesis unit). Therefore, prior to the present invention, this 50-fold difference had to be compensated for by compression work, for example by a compressor. Embodiments of the present invention specifically solve these problems and needs by providing the articles of manufacture, apparatus and processes taught and disclosed herein. [Means for Solving the Problems]

[0023] Accordingly, there are provided methods and systems for minimizing the amount of compression work required for a gas liquefaction system utilizing an air-breathing engine reformer, having or using one or more of the following: (a) reducing the amount of nitrogen; (b) increasing the back pressure of the engine from the standard 1 bar or 2 bar up to a maximum of 5 bar; (c) recovering much of the compression work using a turboexpander to reduce, among other benefits, the costs required for plant operation; (d) utilizing an intensified synthesis loop to achieve acceptable methanol synthesis at a lower overall pressure.

[0024] Further, there are provided gas liquefaction systems and methods having an engine reformer that produces intermediate syngas at a pressure of from about 2 bar to about 5 bar as a means of reducing downstream compression requirements, a syngas compressor that compresses the syngas to a desired downstream synthesis pressure to provide high-pressure syngas, and a downstream synthesis process that converts the high-pressure syngas into a desired product.

[0025] Further, there is provided a gas liquefaction system and method having a downstream synthesis reactor that shifts the equilibrium to selectively extract the products or by-products of the synthesis reaction from unreacted syngas to achieve a high single-pass conversion rate at a lower synthesis pressure, wherein product separation is performed in situ within the synthesis reactor, in a closely coupled manner, or both, whereby the recycle loop to the synthesis reactor is reduced or eliminated, and the compression work for recompression of the recycle gas is reduced, and further, means for separating products from reactants within the reactor, which may include one or more of adsorption, absorption, membrane separation, distillation, and the like.

[0026] Further, there is provided a gas liquefaction system and method having a turboexpander downstream of the recuperator to recover energy from the gaseous product stream that is depressurized before being discharged from the system, and the recovered energy is used to reduce the net compression work for the process, thereby enabling self-sustaining operation.

[0027] Further, there are provided these methods, systems and apparatuses having one or more of the following features. Engine reformer modifications, such as inlet charge boosting or valve timing adjustments, to facilitate good volumetric efficiency and net shaft power output of the engine. Various syngas conditioning steps to remove soot, sulfur, oxygen, carbonyls, and other contaminants. Means for regenerating the adsorbent or sweep stream to recover products and return the adsorbent / sweep material to the reactor. Using the output from the engine reformer to supply heat, electricity, shaft power, or pneumatic / hydraulic power to downstream reactive separation processes. A recuperative heat exchanger for transferring heat from the high-temperature syngas stream to the inlet stream of the turboexpander to increase enthalpy and the work output of the turboexpander, an indirect heat transfer loop for recuperative heat exchange that isolates process streams, heat storage in the indirect heat transfer loop to improve heat utilization, facilitate process start-up, and suppress feedback from process disturbances, and an integrated turboexpander that includes interstage heat exchangers in the expander of a multi-stage compressor.

[0028] Therefore, a method is provided for converting a gas into a final product, the method comprising the steps of receiving a flow of a hydrocarbon fuel source from a source, the composition of which mainly consists of gaseous hydrocarbons and inert gases; partially oxidizing the fuel source in an air-intake reciprocating engine to produce a synthesis gas mixture having an H2 / CO ratio suitable for liquid synthesis; and reducing the workload of a compressor.

[0029] Furthermore, methods and systems having one or more of the following features are provided: The process of reducing the workload of the compressor includes reducing the amount of nitrogen. The process of reducing the workload of the compressor includes increasing the back pressure of an air-intake reciprocating engine. The back pressure is increased up to 5 bar. The back pressure is greater than 2 bar. The process of reducing the workload of the compressor includes using a turbo expander / heat exchanger system. The air-intake reciprocating engine is a rich-burn engine. The air-intake reciprocating engine is a variable compression ratio engine. The air-intake reciprocating engine is a compression-ignition engine. The air-intake reciprocating engine is a spark-ignition engine.

[0030] Furthermore, a system is provided for converting a gas into a final product, the system comprising an inlet port for receiving a flow of a hydrocarbon-based fuel source whose composition is mainly gaseous hydrocarbons and an inert gas from a source, the inlet port being in fluid communication with an air-intake reciprocating engine configured to partially oxidize the fuel source to produce a synthesis gas mixture having an H2 / CO ratio suitable for liquid synthesis, and means for reducing the workload of a compressor.

[0031] Furthermore, methods and systems having one or more of the following features are provided: Means for reducing the workload of the compressor include means for reducing the amount of nitrogen. Means for reducing the amount of nitrogen include an oxygen enrichment unit. Means for reducing the amount of nitrogen include a nitrogen removal unit. Means for reducing the workload of the compressor include increased back pressure of an air intake reciprocating engine. Increased back pressure is up to 5 bar. Increased back pressure is greater than 2 bar. Increased back pressure is greater than 2 bar. Means for reducing the workload of the compressor include using a turboexpander-compressor-heat exchanger. The turboexpander-compressor-heat exchanger system includes three stages. The turboexpander-compressor-heat exchanger system includes a compressor-turbine assembly. The turboexpander-compressor-heat exchanger system consists of two stages, each having a compressor, turbine, and heat exchanger. The turboexpander-compressor-heat exchanger system includes three stages, each having a compressor, turbine, and heat exchanger. Means for reducing the workload of the compressor include a reaction-separation-synthesis loop. An air-intake reciprocating engine is a rich-burn engine. An air-intake reciprocating engine is a variable compression ratio engine. An air-intake reciprocating engine is a compression-ignition engine. An air-intake reciprocating engine is a spark-ignition engine. The fuel source is flare gas. The engine is a compression-ignition engine, including a diesel cycle engine, or a premixed compression-ignition engine. The engine is a spark-ignition engine, including an Otto cycle engine. The engine is an opposed-piston, free-piston, linear internal combustion engine. The engine is a crankshaft-driven opposed-piston internal combustion engine with a crankshaft phaser, which rotates the phase of one piston relative to the phase of the other piston to change the overall compression ratio.

[0032] Furthermore, a system is provided for converting flare gas to methanol while reducing the workload of the compressor, the system comprising a first line for receiving an airflow and a second line for receiving a flare gasflow, the first and second lines being in fluid communication with an air intake engine reformer assembly, and a turbo expander assembly being in fluid communication with a third line, the engine reformer assembly being in fluid communication with the third line, the third line connecting the engine reformer assembly and the turbo expander assembly so that intermediate products from the engine reformer can flow into the turbo expander assembly, the turbo expander assembly being in fluid communication with a fourth line, a fifth line, and The system comprises a turbo expander assembly fluidly communicating with the 6th line, and a methanol synthesis assembly fluidly communicating with the 4th line, the 5th line, and the 6th line, wherein the 4th line connects the turbo expander to the methanol synthesis assembly to provide a first flow from the turbo expander to the methanol synthesis assembly, the 5th line connects the turbo expander to the methanol synthesis assembly to provide a second flow from the turbo expander assembly to the methanol synthesis assembly, and the 6th line connects the turbo expander to the methanol synthesis assembly to provide a third flow from the methanol synthesis assembly to the turbo expander.

[0033] Furthermore, methods and systems having one or more of the following features are provided: The intermediate product is synthesis gas. The first flow from the turboexpander to the methanol synthesis assembly is synthesis gas. The engine is a conventional spark-ignition reciprocating engine that achieves a variable "effective" compression ratio using camshaft phasers that rotate the intake and exhaust camshafts to act on the opening and closing of the valves. The engine is a conventional spark-ignition reciprocating engine that achieves a variable "effective" compression ratio and affects the opening and closing of the valves using a valve train with variable lift and / or variable duration. The engine has a multilink system instead of conventional connecting rods that rotate the crankshaft, and actuator motors change the endpoints of the multilink system. The engine is a two-stroke engine. The engine is a four-stroke engine. The engine speed is varied along with the engine compression ratio to achieve desired combustion and desired exhaust gas composition. The air temperature in the inlet manifold is varied along with the engine compression ratio to achieve desired combustion and desired exhaust gas composition. The air pressure in the intake manifold (e.g., boost level) is varied along with the engine compression ratio to achieve the desired combustion and exhaust gas composition. Alternatively, vapor or hydrogen can be added to the intake air or fuel, and the amount added is varied along with the engine compression ratio to achieve the desired combustion and exhaust gas composition.

[0034] Furthermore, these methods and systems are provided having one or more of the following features: The engine is operated under an ER of at least 1.5. The engine is operated under an ER of at least about 2.5. The engine is operated under an ER of at least about 2.5. The engine is operated under an ER of at least about 3. The engine is operated under an ER of at least about 3. The compression ratio is controlled between 8:1 and 14:1. Downstream of the engine, an integrated heat exchanger, compression system components, and heat exchanger are combined to prepare synthesis gas for a downstream synthesis reactor. Downstream of the engine, there is a downstream synthesis reactor system for producing useful liquid products. A cloud-based remote monitoring system, including AI-trained anomaly detection, dynamically monitors changes in variable valve timing and evaluates and responds to anomalies in the fuel supply. From a CO2e life cycle assessment perspective, when produced from flare gas, it results in negative CO2e emissions of about 40 kg CO2e per kg of final product (in this case, liquid methanol) compared to baseline liquid methanol production from pipelined natural gas. When produced from flare gas and replacing equivalent kg of methanol from pipelined natural gas, the resulting negative CO2e emissions are approximately 70 kg CO2e per kg of final product (methanol). When produced from flare gas and replacing equivalent kg of baseline methanol from coal gasification, the resulting negative CO2e emissions are approximately 130 kg CO2e per kg of final product (methanol). The final product contains methanol. The final product has materials selected from the group consisting of ethanol, ammonia, dimethyl ether, and FT liquids. The fuel source is flare gas from hydrocarbon wells. The fuel source is flare gas from oil wells. The fuel source is flare gas from unconventional oil wells. The fuel source is flare gas, and the flare gas is selected from the group consisting of petrochemical processing, refining, landfill, wastewater treatment, and livestock farming. The fuel gas flow rate is approximately 50,000 scfd to approximately 30,000,000 scfd. The fuel gas flow rate ranges from approximately 500,000 scfd to approximately 20,000,000 scfd.The fuel gas flow rate is approximately 600,000 scfd to approximately 15,000,000 scfd. The fuel gas flow rate is approximately 700,000 scfd to approximately 10,000,000 scfd. [Brief explanation of the drawing]

[0035] [Figure 1] This chart shows the equilibrium constants of methanol synthesis reactions used according to the present invention, where K1 is the equilibrium constant for the CO hydrogenation reaction (R1) in units of atm-2, K2 is the equilibrium constant for the CO2 hydrogenation reaction (R2) in units of atm-2, and K3 is the equilibrium constant for the reverse water-gas shift reaction (R3) without units.

[0036] [Figure 2] This chart shows a surface plot of the equilibrium limit carbon (CO+CO2) conversion rate to methanol as a function of reactor temperature and pressure, according to the present invention. The percentages on the left side of the chart represent the carbon conversion rate for each region of the chart corresponding to a specific temperature and pressure.

[0037] [Figure 3] This is a schematic flowchart of one embodiment of the system and process according to the present invention.

[0038] [Figure 4] This is a schematic flowchart of one embodiment of the system and process according to the present invention, highlighting the differences in methanol synthesis pressure.

[0039] [Figure 5] This table shows the compressor output as a function of engine back pressure for achieving a downstream combined pressure of 50 bar, as used in accordance with the present invention.

[0040] [Figure 6] This is a schematic flowchart of one embodiment of a system and process having a reaction product separator according to the present invention.

[0041] [Figure 7] This is a schematic flowchart of one embodiment of a system and process having reactive by-product separation according to the present invention.

[0042] [Figure 8] This is a schematic flowchart of one embodiment of a system and process having a recuperator and turbo expander according to the present invention.

[0043] [Figure 9] This table shows the compressor output (gross output and net output) in a gas-to-methanol conversion process using a turbo expander (engine back pressure 3 bar, methanol synthesis pressure 50 bar) according to the present invention.

[0044] [Figure 10] This is a schematic flowchart of a system and process embodiment showing an embodiment of an integrated turboexpander system and method (including temperature and pressure operating profiles) for use in an embodiment of a gas-to-methanol conversion system according to the present invention.

[0045] [Figure 11] For example, this is a TS diagram of the thermodynamic state point of one embodiment of the air intake process according to the present invention, which converts flare gas into synthesis gas and then into a value-added product.

[0046] [Figure 12] This is a table showing the values ​​of the global warming potential.

[0047] [Figure 13] This is a TS diagram representing one embodiment of a process, operating conditions, and thermodynamic state points for converting a flag gas to synthesis gas and then to methanol using the system shown in Figure 8, which is equipped with a spark-ignition reciprocating engine according to the present invention.

[0048] [Figure 14]This TS diagram illustrates an embodiment of the process, operating conditions, and thermodynamic state points for converting a flag gas to synthesis gas and then to methanol using the system shown in Figure 8, which has a compression-ignition reciprocating engine according to the present invention.

[0049] [Figure 15] This is a schematic flow diagram of one embodiment of a system and process having a flow-adjustable turbo expander and compressor according to the present invention. [Figure 15A] This is a schematic flow diagram of one embodiment of a system and process having a flow-adjustable turbo expander and compressor according to the present invention. [Figure 15B] This is a schematic flow diagram of one embodiment of a system and process having a flow-adjustable turbo expander and compressor according to the present invention. [Figure 15C] This is a schematic flow diagram of one embodiment of a system and process having a flow-adjustable turbo expander and compressor according to the present invention. [Modes for carrying out the invention]

[0050] The present invention generally relates to systems, apparatus, and methods for economically recovering usable fuel from hydrocarbon gases, and in particular, embodiments that achieve such recovery in smaller, isolated, or remote locations or sites for flare gases.

[0051] Generally, embodiments of the present invention include devices and systems for reducing the workload of compressors required in reformer-based hydrocarbon processing systems, such as gas liquefaction systems (e.g., compression requirements such as the number and size of compressors and the energy required to operate them).

[0052] Generally, embodiments of the present invention include devices and systems for reducing the workload of a compressor required for a reciprocating engine reformer-based hydrocarbon processing system, such as a gas liquefaction system.

[0053] Generally, embodiments of the present invention relate to systems and methods having gas liquefaction systems and gas liquefaction processes, such as processing flare gas into methanol. In these systems, an air intake engine reformer produces a synthesis gas intermediate, which is further converted to methanol in a downstream synthesis process. Examples of such gas liquefaction systems are disclosed in U.S. Patent Publication 2022 / 0388930 and U.S. Patent Applications 17 / 953,056 (filed September 26, 2022) and 17 / 984,126 (filed November 9, 2022), the entirety of which these disclosures are incorporated herein by reference. In particular, embodiments of the present invention relate to devices, systems, and methods for improving and strengthening the pressure difference associated with the air intake engine reformer in these gas liquefaction systems and gas liquefaction processes, thereby reducing the workload of the compressor required to operate these systems. Therefore, embodiments of this apparatus and system that reduce the compressor workload required for reciprocating engine reformer-based hydrocarbon processing systems are used in conjunction with or as part of these gas liquefaction systems.

[0054] Figure 1 shows the equilibrium constants for three typical reactions in methanol synthesis. Note that any two of these reactions (e.g., R1 and R2) are linearly independent, and the third (e.g., R3) is a combination of the other two. Achieving the stoichiometry of ideal synthesis gas is a direct method of producing methanol in the downstream synthesis steps according to reaction equations (1) to (3). (R1) CO + 2H2 ⇔ CH3OH ΔHr = -90.7 kJ / mol (Hydrogenation of CO) (R2) CO2 + 3H2 ⇔ CH3OH + H2O ΔHr = -49.5 kJ / mol (Hydrogenation of CO2) (R3) CO2 + H2 ⇔ CO + H2O ΔHr = 41.2 kJ / mol (reverse water-gas conversion)

[0055] The hydrogenation reactions (R1 and R2) that produce methanol from CO and CO2 are exothermic, while the RWGS reaction (R3) is endothermic. Therefore, the overall equilibrium reaction to methanol is preferable at low temperatures. However, since catalytic activity (and associated reaction rates) decreases with temperature, there is a practical minimum temperature for the reactor.

[0056] Figure 2 shows the predicted one-step carbon (CO+CO2) conversion at equilibrium as a function of reactor temperature and pressure. Lower temperatures and higher pressures are preferable to obtain higher conversion rates. These results were generated using measured equilibrium data of R1-R3 in the stoichiometry (S=2) of an ideal synthesis gas from an air intake reformer. Figures 1 and 2 reveal fundamental chemical and physical limitations, which have historically been linked to relatively high synthesis pressures and associated compression work in commercial methanol synthesis processes. This is addressed and improved by embodiments of the present invention by reducing the compressor work.

[0057] Furthermore, referring to Figure 5, the predicted compressor work (total synthesis gas compression only) is shown as a function of engine exhaust back pressure downstream of a synthesis pressure of 50 bar. These data are generated using chemical process simulations that perform mass and energy balancing for the embodiment of gas liquefaction systems and methods of the type shown, for example, in Figure 4. The synthesis gas compressor is treated as a three-stage compressor with intercooling. The isentropic efficiency of this compressor is assumed to be 75%, as is typical for industrial centrifugal and reciprocating compressors. The synthesis gas ratio-adjusted recirculation flow enters the compressor at the second stage inlet. Increasing the engine exhaust back pressure from 2 bar to 3 bar reduces the compression work by 20.4%. Further increasing the back pressure from 2 bar to 4 bar reduces the compression work by 28.0%. Therefore, the reduction in engine exhaust back pressure yield and the optimal value in the embodiment of Figure 4 would be in the range of 2 to 5 bar in order to balance the reduction in compression work with the reduction in intake and performance of the engine reformer.

[0058] Referring to Figure 9, the compressor output (gross and net) in an example implementation of a gas-to-methanol conversion process using a turbo expander, assuming an engine back pressure of 3 bar and a methanol synthesis pressure of 50 bar, is shown. These data were generated using chemical process simulations with mass and energy balances performed for specific examples of gas liquefaction systems and methods of the type shown, for example, in Figure 8. The total compressor work, consisting of a synthesis gas compressor, a primary recirculation compressor, and an inlet air compressor, is largely accounted for by the synthesis gas compressor. The total compressor output is 1055.7 kW, which is usually too high for self-sustaining operation without energy recovery. The turbo expander recovers 292.5 kW of power, reducing the compressor's power requirement to 763.2 kW. It is preferable to use the brake power generated by the engine reformer in a self-sustaining operation scenario.

[0059] The advantages of this method, apparatus, and system include, in particular, the following: 1) Lower capital investment and operating costs compared to conventional technologies; 2) Suitable for remote and distributed applications, as the process is self-sustaining in terms of power. It also improves upon conventional commercial methanol synthesis technologies, enabling small-scale, distributed, and self-sustaining applications utilizing underutilized gases.

[0060] Although methanol synthesis is used as an example in this specification, it is understood that the method and system are applicable to other similar downstream synthesis processes. Therefore, generally speaking, embodiments of the method and system described herein can be used together with, or in conjunction with, systems and methods for converting uneconomical hydrocarbon fuels (e.g., stranded gas, associated gas, landfill gas, flare gas, small pocket gas, remote gas) into high-value, easily transportable products (e.g., methanol, ethanol, ammonia, dimethyl ether, FT liquids, and other fuels or chemicals).

[0061] In one embodiment of the present invention, a system and method reduce the gas compression requirements required for the synthesis of methanol (or other downstream products such as ammonia or FT liquids) when converting strand gas to products (preferably high-value, easily transportable products such as methanol, ethanol, ammonia, dimethyl ether, FT liquids, or other fuels or chemicals) on a small, modular, and decentralized basis in an integrated system with an engine-based reformer. Gas compression requirements affect the overall capital investment and operating costs of the process and impact the overall profitability of the modular plant. Compressors used to raise the pressure of the synthesis gas exiting the engine reformer to a level suitable for downstream methanol synthesis can account for nearly half of the total capital investment of the plant. Furthermore, in practical applications, a self-sufficient plant that requires little to no external power supply is desirable. Since the majority of power requirements are accounted for by the power needed to drive the compressor, the workload of the compressor is linked to the operating costs and self-sufficiency of the plant.

[0062] Improvements to the compression work, for example, a reduction in the amount of work, in a gas-to-methanol conversion plant that uses an engine-based reformer to produce synthesis gas intermediates are provided in embodiments of the present invention. The reduction in compressor work can be achieved by several devices and processes, for example, through one or more of the following uses: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from the standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover a large portion of the compression work and reduce the operating costs of the plant; (d) using an enhanced synthesis loop to achieve methanol synthesis that is acceptable at lower overall pressures.

[0063] Monetizing strand gas resources, such as associated gases from petroleum production, typically involves converting the gas into products or intermediates that are liquid at room temperature (e.g., methanol, FT liquid) or readily condensable gases (e.g., ammonia). Both ammonia and methanol synthesis are highly exothermic, with limited equilibrium and an overall decrease in the number of moles in the reaction. Due to their exothermic nature, good conversion rates are obtained at low temperatures. However, catalytic activity decreases at low temperatures, requiring larger reactors and higher catalyst loads, thus demanding the minimum practical reactor temperature. Increasing the reactor pressure shifts the equilibrium to a higher conversion rate. In some embodiments, methanol plants synthesize methanol under nominal pressures of 50 bar, far higher than the nominal exhaust pressure from engine-based reformers, particularly air-intake engine-based reformers. This high pressure requires considerable compression work, resulting in high capital investment and operating costs. Despite the high pressure, the single-pass conversion rate remains low, so it is possible to use a recirculation loop to increase the overall conversion rate, but this would require a larger reactor and more complex and expensive downstream separation process.

[0064] In a preferred embodiment, one or more devices and processes that reduce the workload of the compressor are used as part of a small, modular, decentralized self-sufficient plant for converting strand gas into an easily transportable, replaceable product using an engine-based reformer and synthesis gas intermediate.

[0065] Embodiments of the present invention include a reciprocating engine for generating reprocessing gas, preferably synthesis gas, and are advantageous under certain circumstances, and include one or more devices and processes for reducing the workload of compressors related to or used with gas liquefaction systems and methods. Embodiments of the system are preferably modular and can be easily deployed in hard-to-access locations where flare gas is generated, in locations with limited system footprint, and combinations and variations thereof.

[0066] An objective of embodiments of the present invention is, in particular, to reduce the workload of compressors required when converting otherwise uneconomical hydrocarbon fuels (e.g., strand gas, associated gas, landfill gas, flare gas, small-scale gas field gas, remote gas) into high-value, easily transportable products (e.g., methanol, ethanol, ammonia, dimethyl ether, FT liquids, and other fuels or chemicals) using an autonomous modular system.

[0067] Embodiments of the present invention focus on a reciprocating engine and a method for operating such an engine that can handle the various combustion characteristics of fuel sources, including fuel sources (such as flare gas) generated from oil fields and landfills. One reason why these gases are uneconomical is that their fuel composition fluctuates greatly. As a result of these compositional fluctuations, combustion characteristics such as calorific value, cetane number (delay in fuel ignition timing), and octane number (resistance to pre-ignition due to compression) are affected. These variability occurs for each source, and even within the same source, it can occur from day to day (temporary), from season to season (especially biogas), and as the source changes over time. Embodiments of the present invention address and solve these problems.

[0068] Conventional air-intake reciprocating engines are typically designed to use fuels with narrow fuel specifications. For example, the compression ratio of a car's gasoline engine is selected to match the quality of the fuel used. "Regular" gasoline in the United States has an octane rating of 86-87. Higher-performance engines (e.g., with higher compression ratios) may require premium gasoline with an octane rating of 91-94.

[0069] One embodiment of the present invention is a configuration, operation, or both, for operating a commercially available reciprocating engine (e.g., a commercial engine) under rich conditions with a high fuel-to-air ratio to produce synthesis gas. To operate the engine deviating from its intended design point and to ensure good operation even with fuels exhibiting wide variations in octane and cetane numbers, this invention modifies engine operating parameters such as compression ratio, intake manifold air temperature, intake manifold air pressure, and engine speed. This embodiment applies to both compression-ignition engines (diesel cycle) and spark-ignition engines (Otto cycle). In spark-ignition engines, ignition timing can also be used to adapt engine operation to fuel variations. Preferably, this embodiment is used in a system having one or more of the apparatus and processes to reduce the workload of the compressor.

[0070] Embodiments of the present invention can be used to extract uneconomical hydrocarbon fuels, mainly gaseous hydrocarbons, from oil wells or remote locations and convert them into more valuable and easily condensable gas or liquid compounds, such as methanol. Associated gases and flare gases produced as by-products in oil fields can also be used as fuel sources. Flare gases generated in industrial processes, such as those produced in refineries, can also be used as fuel sources. Biogas generated from landfills or anaerobic digesters can also be used as fuel sources.

[0071] Embodiments of the present invention are particularly useful in small-scale plants using one or more synthesis gas engines and targeting an inlet gas flow rate of 600,000 sccd (standard cubic feet / day). The size of such plants can vary from 80,000 sccd to 3,000,000 sccd, or from 20,000 sccd to 100,000 sccd.

[0072] Embodiments of the present invention can be incorporated into one or more modular, interconnected skids or containers manufactured in a central manufacturing facility and subsequently installed on-site. The system consists of a small number of modules, which, when connected on-site, form an integrated system. This modularity of assembly allows for application to remote locations with a wide range of inlet gas supply volumes while minimizing on-site labor.

[0073] Referring to Figure 3, a general embodiment of a system and method for converting waste gas, such as flare gas, into a value-added product, such as methanol, is shown. System 100 has a reforming step 101 and a synthesis step 102. System 100 has an air intake 110, which supplies air to a compressor 111 that compresses air. The compressed air is fed through a heat exchanger 120a to a mixer 113. The system has an intake 110 for waste gas, such as flare gas. The waste gas flows through a heat exchanger 120b to the mixer 113. The mixer 113 supplies a predetermined mixture of air and waste gas to a reformer 114, as taught and disclosed herein.

[0074] The fuel-air mixture formed in the mixer 113 is preferably rich, and more preferably has an overall fuel-to-air equivalent ratio (Φ or ER) greater than 1, greater than 1.5, greater than 2, greater than 3, about 1.5 to about 4.0, about 1.1 to about 3.5, about 2 to about 4.5, about 1.1 to about 3, and greater.

[0075] It is understood that oxygen can be added to the air. Water or steam can also be injected into the air-fuel mixture, or into the air or fuel alone. Approximately 1% to 20% (mol) of water can be injected, as can approximately 10% to 15% (mol), 5% to 17% (mol), more than 5% (mol), more than 10% (mol), more than 15% (mol), and less than 25% (mol). After oxygen concentration, the combustion air can contain approximately 21% to 90% oxygen. The “air intake” reformers and air intake engines used here also include engines that use air modified with water, oxygen, or both.

[0076] The reformer 114 burns a predetermined mixture of exhaust gas and air (e.g., flare gas and air) to form a reprocessed gas (e.g., synthesis gas). The synthesis gas passes through heat exchangers 120a and 120b and flows into a filter 115, such as a particulate filter.

[0077] After passing through filter 115, the reprocessed gas (e.g., synthesis gas) flows into a guard bed reactor assembly 116 having two guard bed reactors 116a and 116b. The guard bed reactors 116 are equipped with materials, such as catalysts, to remove contaminants and other substances from the synthesis gas that could adversely affect, hinder, or contaminate subsequent equipment or processes in the system. For example, the guard bed reactors 116 may include catalysts, adsorbents, or other materials for removing sulfur (e.g., iron sponge, zinc oxide, or similar) and halogenated compounds.

[0078] After exiting the guard bed reactor 116, the reprocessing gas (e.g., synthesis gas) flows to the deoxygenation ("deoxo") reactor 117. The deoxo reactor 117 removes excess oxygen from the reprocessing gas (e.g., synthesis gas) by oxidizing the flammable compounds in the mixture (e.g., methane, carbon monoxide, hydrogen). The oxygen is converted to water. The catalyst for the deoxygenation reaction is platinum, palladium, and other active materials supported on alumina or other catalyst support materials.

[0079] System 100 includes a cooling system 150 through which a cooling fluid, such as cooling water, flows in a cooling line, such as 151. Other cooling means, such as direct air cooling, are also envisioned.

[0080] After exiting the deoxo reactor 117, the reprocessed gas (e.g., synthesis gas) flows into the heat exchanger 120c. The reprocessed gas then flows from the heat exchanger 120c to a moisture removal unit 118, such as a water knockout drum, demister, dryer, membrane, cyclone, desiccant, or similar device, where moisture is removed from the reprocessed gas (e.g., synthesis gas). Generally, the reprocessed gas (e.g., synthesis gas) exiting unit 118 should contain less than approximately 5%, 2%, 1%, and 0.1% moisture by weight.

[0081] The overall (approximate) reaction of a rich fuel-air mixture to synthesis gas through partial oxidation is represented by the following equation: ФCH4+ 2[O2+ 3.76N2] → aCO + bH2+ cCO2+ dH2O + 7.52N2 The stoichiometric coefficients a, b, c, and d are determined by chemical reaction kinetics, conservation of atomic species, and reaction conditions.

[0082] Trace components in the gas exiting the reformer may include, in addition to synthesis gas, water vapor, carbon dioxide, and various unburned hydrocarbons.

[0083] After leaving unit 118, the dry reprocessed gas (e.g., synthesis gas) is sent to the synthesis stage 102. In stage 102, the dry reprocessed gas (e.g., synthesis gas) flows to assembly 130. Assembly 130 controls the addition of hydrogen to the dry reprocessed gas (e.g., synthesis gas) from line 131. In this way, the ratio of the components of the synthesis gas is adjusted and controlled to a predetermined ratio. Hydrogen is supplied from hydrogen separation unit 139. The ratio-adjusted dry reprocessed gas (e.g., synthesis gas) leaves assembly 130 and flows into compressor 132. Compressor 132 compresses the regenerated gas (e.g., synthesis gas) to an optimal pressure for use in the synthesis unit 133, as taught and disclosed herein. Any synthesis unit 133 is a two-stage unit comprising a first reactor unit 133a and a second reactor unit 133b. Each reactor is a pressure vessel through which the process gas flows in an exothermic reaction through a catalyst layer. The catalyst layer tubes are typically immersed in a pool of cooling water at a controlled temperature and pressure. The synthesis unit 133 also includes a heat exchanger 120e.

[0084] The synthesis unit 133 converts the ratio-adjusted dry reprocessed gas (e.g., synthesis gas) into value-added products (e.g., methanol, ethanol, mixed alcohols, ammonia, dimethyl ether, FT liquids, and other fuels or chemicals). The value-added products (e.g., methanol) flow into the heat exchanger 120d. The value-added products (e.g., methanol) flow into the recovery unit 140. The recovery unit 140 recovers the value-added products (e.g., methanol) and sends them to line 141 for sale, storage, or further processing.

[0085] Generally, synthesis gas is compressed to pressures of about 15 to about 100 bar, preferably 30 to 50 bar, about 25 to about 80 bar, at least about 10 bar, at least about 25 bar, at least about 50 bar, and above and below. The temperature of the pressurized synthesis gas is about 150°C to about 350°C, preferably 250°C, about 200°C to about 300°C, about 250°C to about 375°C, above 125°C, above 150°C, above 200°C, above 250°C, above 350°C, above 400°C, and above and below. The pressure and temperature controlled synthesis gas is supplied to reactors to convert the synthesis gas into more useful, easily transportable, and economically feasible products such as methanol, ethanol, mixed alcohols, ammonia, dimethyl ether, FT liquids, and other fuels and chemicals. In a preferred embodiment, an actively cooled reactor, such as a heat exchange reactor or a boiling water reactor, and a copper-containing catalyst such as Cu / ZnO / Al2O3 are used to produce methanol from synthesis gas via a hydrogenation reaction of carbon monoxide, a hydrogenation reaction of carbon dioxide, and a reverse steam shift reaction.

[0086] Generally, in preferred embodiments, the characteristic length scale of the reactors used in this system is sufficiently small (e.g., microchannels or minichannels) and can be molded into unprecedented shapes and topologies using new 3D printing techniques for metals and other high-temperature materials, enabling compact packaging and precise control of reaction conditions. Other strategies for enhancing downstream synthetic reactions can also be considered, such as selectively removing products from the reactor in situ or in a tightly coupled manner. This can shift equilibrium-limiting reactions to higher conversion rates. This process enhancement can minimize the need for large-scale recirculation flows and allow reactions to proceed under milder conditions (e.g., low pressure), improving process safety margins and providing other benefits.

[0087] Typically, when synthesis gas is reacted to form higher-value products, unreacted hydrogen is also produced. This hydrogen can be recovered and sold, or used to power gas turbines or second generators to produce additional electricity.

[0088] Generally, the H2 / CO ratio of synthesis gas produced by an engine can be adjusted to suit the downstream conversion process. For example, in methanol synthesis and Fischer-Tropsch (FT) synthesis, the ideal H2 / CO ratio is 2-3. In ammonia synthesis and hydrogen production, the highest possible H2 / CO ratio is desirable, and this ratio can be increased, for example, by adding steam to accelerate the water-gas conversion reaction. In ammonia and hydrogen production, CO is not required in the downstream synthesis process. Therefore, the by-products of CO and CO2 can be recovered, sequestered, stored, or used for other purposes.

[0089] Furthermore, the recovery unit 140 also has a line that carries the gas separated from the value-added product (e.g., methanol) to valve 135, from where it is sent to the hydrogen separation unit 139, the recirculation loop 136, or both. The recirculation loop is equipped with a compressor 134 and valve 138 for returning unreacted synthesis gas to the synthesis unit 133. Hydrogen separation can be performed in the hydrogen separation unit 139 by membrane separation or pressure swing adsorption (PSA), etc.

[0090] Preferably, the system and process of Figure 3 has one or more devices and processes for reducing the workload of the compressor. Thus, the system and process of Figure 3 has or can use one or more of the following: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from a standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover much of the compression work, thereby reducing costs in particular among other efficiencies for operating the plant; and (d) utilizing an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressures. These devices and processes for reducing the workload of the compressor can be used in conjunction with the system and process of Figure 3, parts of the system and process of Figure 3 (e.g., modular, integrated, and combinations thereof), and combinations and variations of this embodiment.

[0091] The overall conversion process from fuel to useful products can be described using a TS diagram with the properties of air in a standard approximation of process air. Figure 11 shows a temperature-entropy (TS) diagram relating to the general operation and thermodynamics of a flare gas to methanol conversion system of the type shown in Figure 3, for example. The overall conversion process from waste gas, e.g., flare gas, to useful products, e.g., methanol, is described using the TS diagram in Figure 11. This diagram uses the properties of air in a standard approximation of process air. Figure 11 outlines a general solution and operation of a system like the one shown in Figure 3, from the standpoint of thermodynamics, temperature, and pressure. This diagram shows the process starting point under ambient conditions, high temperature and high pressure conditions for rich partial oxidation in the reformer, and high pressure and low temperature reaction for methanol synthesis. Thus, the temperature-entropy ratios are shown by dashed lines 201 for 60 atmospheres, 202 for 30 atmospheres, 203 for 8 atmospheres, and 204 for 1 atmosphere. (1 atmosphere corresponds to 1.013 bar.) The temperature and pressure of the incoming air (e.g., 110 in Figure 3) and exhaust gas (e.g., flare gas) are at point 206 (Figure 11). The operating conditions for the reforming stage (e.g., 101 in Figure 3) are shown in zone 210 (Figure 11). Zone 210 has a temperature of 900°C or higher. Zone 210 has two subzones, 210a and 210b. Subzone 210a is a low-pressure zone (less than 1 bar to about 25 bar). Subzone 210b is a high-pressure zone (about 20 bar to about 100 bar), and is a high-pressure zone in particular for rich partial oxidation conditions in the reformer (e.g., 114 in Figure 3), which are preferred conditions for embodiments of the present invention. The optimal operation for the synthesis stage (e.g., 131 in Figure 3) is shown in zone 211 for methanol synthesis. Zone 211 is characterized by a temperature of 200-300°C and a pressure of approximately 20-100 bar. The preferred zone for methanol production is 200-300°C and a pressure of 30-100 bar.

[0092] Therefore, Figure 11 illustrates conditions that may be commonly used in a system performing the conversion from flare gas to the final product (methanol in this case), preferably with a neutral energy balance (i.e., supplying all the energy necessary for the operation of the system and process, or supplying a positive surplus of energy). The specific entropy axis (horizontal axis) is in units of kJ / kg°C and represents the entropy per unit mass of air. This type of diagram is a convenient way to illustrate physical processes such as compression and expansion (nearly vertical lines between pressure levels) and heat exchange (usually at nearly constant pressure). Ideal compression and expansion are isotropic, meaning there is no change in entropy between two pressure levels. Compression by actual equipment is anisotropic, as shown by non-vertical lines. The temperature axis (vertical axis) is in °C and represents the temperature of a fluid assumed to have similar properties to air. The relationship between temperature and constant pressure lines is governed by the physical properties of the fluid. One of the advantages of TS diagrams is that they allow for a visual representation of the relationship between physical processes and components.

[0093] The partial oxidation window 210 defines the temperature and pressure range in which critical partial oxidation (POX) reactions for synthesis gas production occur. This range defines reaction conditions that result in reaction times (typically 5–50 milliseconds) that are commensurate with the combustion residence time in the reformer (e.g., gas turbine). Generally, since the POX reaction occurs at a much higher temperature than the downstream synthesis (e.g., methanol) reaction, the temperature needs to be lowered in a heat exchanger before the methanol reactor.

[0094] The methanol synthesis window 211 defines the temperature and pressure range in which methanol synthesis reactions occur. This range defines reaction conditions that yield a reasonable equilibrium conversion rate for an equilibrium-limited reaction. In this exothermic process, low temperatures are desirable to increase the equilibrium conversion rate, but the low-temperature range is limited by ensuring sufficient catalytic activity. As the pressure increases, the equilibrium concentration increases due to the net decrease in the number of moles in the reaction, but compression costs and design are required for high pressure. Figure 11 specifically illustrates the methanol synthesis window, but it can be seen that similar conditions are required for other possible downstream synthesis reactions, such as the Fischer-Tropsch synthesis.

[0095] Figure 4 shows an embodiment of a system and method for converting flare gas into a value-added product, such as methanol. System 1600 has a reforming step 1601 and a synthesis step 1602. System 1600 has an air intake that supplies air to a compressor 1611, which compresses the air. The compressed air is supplied to a mixer through a heat exchanger. The system is equipped with a flare gas intake. The flare gas flows through a heat exchanger to a mixer. The mixer supplies a predetermined mixture of air and exhaust gas to a reformer 1614, which is a reciprocating engine, as taught and disclosed herein.

[0096] The fuel-air mixture formed in the mixer is preferably rich, and more preferably has an overall fuel-to-air equivalent ratio (Φ or ER) greater than 1, greater than 1.5, greater than 2, greater than 3, about 1.5 to about 4.0, about 1.1 to about 3.5, about 2 to about 4.5, about 1.1 to about 3, and greater.

[0097] It is understood that oxygen can be added to the air. Water or steam can also be injected into the air-fuel mixture, or into the air or fuel alone. Approximately 1 to 20% (mol) of water can be injected, as can approximately 10 to 15% (mol) of water, approximately 5 to 17% (mol) of water, more than 5% (mol) of water, more than 10% (mol) of water, more than 15% (mol) of water, and less than 25% (mol) of water. After oxygen concentration, the combustion air can contain approximately 21% (mol) to 90% (mol) of oxygen. The “air intake” reformers and air intake engines used here also include engines that use air that has been reformed by adding water, oxygen, or both.

[0098] The reciprocating engine 1614 produces synthesis gas by partially burning a predetermined mixture of flare gas and air. The synthesis gas passes through a heat exchanger and flows into a filter, such as a particulate matter filter.

[0099] After passing through the filter, the synthesis gas flows into a guard bed reactor assembly, which optionally has two guard bed reactors. After leaving the guard bed reactor, the synthesis gas flows into a deoxo reactor. The deoxo reactor removes excess oxygen from the reprocessed gas (e.g., synthesis gas).

[0100] This system incorporates a cooling system that uses a cooling fluid, such as cooling water, which flows through a cooling line. Other cooling methods, such as direct air cooling, are also envisioned.

[0101] After leaving the deoxo reactor, the synthesis gas flows into a heat exchanger where it is cooled. The reprocessed gas (e.g., synthesis gas) then flows from the heat exchanger to a moisture removal unit (e.g., water knockout drum, demister, dryer, membrane, cyclone, desiccant, etc.) where moisture is removed from the synthesis gas. Generally, the synthesis gas leaving the moisture removal unit should contain only about 5%, 2%, 1%, and 0.1% moisture by weight.

[0102] After leaving the moisture removal unit, the dry synthesis gas flows into the synthesis stage 1602. In stage 1602, the dry synthesis gas flows into an assembly to which a hydrogen-rich gas is added in a controlled manner. In this way, the ratio of the components of the synthesis gas is adjusted and controlled to a predetermined ratio. The hydrogen is supplied from the hydrogen separation unit 1639. The adjusted ratio dry synthesis gas leaves the assembly and flows into the compressor 1632. The compressor 1632 compresses the synthesis gas to an optimal pressure for use in the synthesis unit 1633 (which is an optional two-stage unit comprising a first reactor unit 1633a and a second reactor unit 1633b), as taught and disclosed herein. The synthesis unit 1633 also comprises a regenerative heat exchanger.

[0103] The synthesis unit 1633 converts the ratio-adjusted dry synthesis gas into a value-added product, such as methanol. The methanol flows into a heat exchanger (i.e., a cooler) and then into the recovery unit 1640. The recovery unit 1640 recovers the condensed methanol, which then flows through the line for sale, storage, or further processing.

[0104] Furthermore, the recovery unit 1640 has a line through which unreacted gas separated from methanol flows to a T-shaped connector, from which it is sent to the hydrogen separation unit 1639, the recirculation loop, or both. The recirculation loop is equipped with a compressor and valves for returning methanol to the synthesis unit 1633.

[0105] Preferably, the system and process in Figure 4 operates as described above under the conditions shown in Figure 5. In embodiments, the system and process in Figure 4 may include one or more devices and processes for reducing the compressor workload. Thus, the system and process in Figure 4 may have or use one or more of the following: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from the standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover most of the compression work and reduce the cost of operating the plant, along with other efficiencies; and (d) using an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressures. These devices and processes for reducing the compressor workload can be used in conjunction with the system and process in Figure 4, for example, as modular, integrated, or a combination thereof, and combinations and variations of this combination method are also possible.

[0106] Referring to Figure 6, embodiments of a system and method for converting flare gas into value-added products, such as methanol, are shown. System 1800 is configured to reduce the required compression work by raising the engine back pressure higher than the ambient pressure, up to approximately 5 bar.

[0107] System 1800 comprises a reforming stage 1801 and a synthesis stage 1802. System 1800 includes an air intake that supplies air to a compressor 1811 that compresses air. The compressed air is supplied to a mixer through a heat exchanger. The system includes a flare gas intake. The flare gas flows through a heat exchanger 1820b to a mixer 1813. The mixer 1813 supplies a predetermined mixture of air and exhaust gas to a reformer 1814, which is a reciprocating engine, as taught and disclosed in this specification.

[0108] The fuel-air mixture formed in the mixer is preferably rich, and more preferably has an overall fuel-to-air equivalent ratio (Φ or ER) greater than 1, greater than 1.5, greater than 2, greater than 3, about 1.5 to about 4.0, about 1.1 to about 3.5, about 2 to about 4.5, about 1.1 to about 3, and greater.

[0109] It is understood that oxygen can be added to the air. Water or steam can also be injected into the air-fuel mixture, or into the air or fuel alone. Approximately 1 to 20% (mol) of water can be injected, approximately 10 to 15% (mol) of water, approximately 5 to 17% (mol) of water, more than 5% (mol) of water, more than 10% (mol) of water, more than 15% (mol) of water, and less than 25% (mol) of water. After oxygen concentration, the combustion air can contain approximately 21% (mol) to 90% (mol) of oxygen. The “air intake” reformers and air intake engines used herein also include engines that use air that has been reformed by adding water, oxygen, or both.

[0110] The 1814 reciprocating engine produces synthesis gas by partially burning a predetermined mixture of flare gas and air. The synthesis gas passes through a heat exchanger and flows into a filter, such as a particulate filter.

[0111] After passing through the filter, the synthesis gas flows into a guard bed reactor assembly, which optionally has two guard bed reactors. After leaving the guard bed reactor, the synthesis gas flows into a deoxo reactor. The deoxo reactor removes excess oxygen from the reprocessed gas (e.g., synthesis gas).

[0112] This system incorporates a cooling system that uses a cooling fluid, such as cooling water, which flows through a cooling line. Other cooling methods, such as direct air cooling, are also envisioned.

[0113] After leaving the deoxo reactor, the synthesis gas flows into a heat exchanger for cooling. The reprocessed gas (e.g., synthesis gas) then flows from the heat exchanger to a moisture removal unit (e.g., water knockout drum, demister, dryer, membrane, cyclone, desiccant, etc.) where moisture is removed from the synthesis gas. Generally, the synthesis gas leaving the moisture removal unit should contain less than approximately 5%, 2%, 1%, and 0.1% moisture by weight.

[0114] After leaving the moisture removal unit, the dry synthesis gas enters the synthesis stage 1802. In stage 1802, the dry synthesis gas flows to an assembly that controls the addition of hydrogen-rich gas to the dry synthesis gas. In this way, the ratio of the components of the synthesis gas is adjusted and controlled to a predetermined ratio. Hydrogen is supplied from the hydrogen separation unit 1839. The ratio-adjusted dry synthesis gas leaves the assembly and flows to the compressor 1832. The compressor 1832 compresses the synthesis gas to an optimal pressure for use in the synthesis unit 1833 (which is an optional two-stage unit comprising a first reactor unit 1833a and a second reactor unit 1833b), as taught and disclosed herein. The synthesis unit 1833 also comprises a regenerative heat exchanger.

[0115] The synthesis unit 1833 converts the ratio-adjusted dry synthesis gas into value-added products, such as methanol. The methanol flows into a heat exchanger (i.e., a cooler) and then into the recovery unit 1840. The recovery unit 1840 recovers the condensed methanol and sends it into the line for sale, storage, or further processing.

[0116] Furthermore, the recovery unit 1840 has a line that carries the unreacted gas separated from methanol to a T-connector, from which it is sent to the hydrogen separation unit 1839, the recirculation loop, or both. The recirculation loop is equipped with a compressor and valves for returning methanol to the synthesis unit 1833.

[0117] Stage 1802 has a line 1883 for recovering spent methanol from unit 1833b and sending it to heat exchanger 1820d. Stage 1802 also has a methanol desorber 1880 equipped with a pump 1881. Line 1882 for the desorber 1880 carries the methanol-rich product to heat exchanger 1820g.

[0118] In the operation of System 1800, the preferred process uses a two-stage methanol synthesis reactor, with reaction separation performed only in the second stage (Rxtr2)1833b. The first stage (Rxtr1)1833a is generally far from equilibrium, and reaction separation is not guaranteed. The example shown in this figure is reaction absorption or membrane separation by liquid sweep. Methanol is selectively removed from the reactor, producing a methanol-depleted gas stream mainly containing unreacted synthesis gas and a methanol-rich absorbent stream. Compared to other embodiments, the main recirculation loop is not used due to the improved single-pass conversion. The methane-rich absorbent passes through a valve to reduce pressure and desorb methanol. The desorbed methanol is condensed and sent to the product stream. The regenerated absorbent is pumped back to the synthesis reactor pressure and recirculated to the reactor. Since the absorbent is nearly incompressible, the pumping work of the absorbent is minimized compared to the work of the synthesis gas compressor. The reactor can use either a trickle bed or a membrane reactor (on the permeate side) for the absorption liquid. Methanol not distributed into the absorption liquid is condensed from the gas phase in a downstream separation step and mixed with the methanol product stream.

[0119] In embodiments, the system and process of Figure 6 may include one or more devices and processes for reducing the compressor workload. Thus, the system and process of Figure 6 may include or use one or more of the following: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from the standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover most of the compression work, thereby reducing the cost of operating the plant, along with other efficiencies; and (d) using an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressures. These devices and processes for reducing the compressor workload can be used in conjunction with the system and process of Figure 6, for example, as part of the system and process of Figure 6, or as combinations and variations of this association, such as modular, integrated, and combinations thereof.

[0120] In this embodiment, the system and process utilize reaction separation. This system and process typically uses a two-stage methanol synthesis reactor, with reaction separation performed only in the second stage (Rxtr2). The first stage (Rxtr1) is generally far from equilibrium, and reaction separation is not guaranteed. This system performs reaction absorption by liquid sweep or membrane separation. Methanol is selectively removed from the reactor, producing a methanol-reduced gas stream mainly containing unreacted synthesis gas and a methanol-rich absorbent stream. Compared to other systems, such as those shown in Figure 3, the single-pass conversion rate is improved, so a main recirculation loop may not be necessary, and preferably is not. The methane-rich absorbent passes through a valve to reduce pressure and desorb methanol. The desorbed methanol is condensed and sent to the product stream. The regenerated absorbent is pumped back to the synthesis reactor pressure and recirculated to the reactor. Since the absorbent is nearly incompressible, the pumping work for the absorbent is minimized compared to the work of the synthesis gas compressor. The reactor may be a trickle bed type or a membrane reactor with an absorbent (sweep) located on the membrane permeate side. Methanol not distributed to the absorbent is condensed from the gas phase in a downstream separation step and mixed with the methanol product stream. This system and process may include one or more devices or processes that reduce the workload of the compressor.

[0121] Referring to Figure 7, embodiments of a system and method for converting flare gas into a value-added product, such as methanol, are shown. System 1900 comprises a reforming step 1901 and a synthesis step 1902. System 1900 includes an air intake that supplies intake air to a compressor 1911 that compresses air. The compressed air is supplied to a mixer through a heat exchanger. The system includes a flare gas intake. The flare gas flows through a heat exchanger 1920b to a mixer 1913. The mixer 1913 supplies a predetermined mixture of air and exhaust gas to a reformer 1914, which is a reciprocating engine, as taught and disclosed herein.

[0122] The fuel-air mixture formed in the mixer is preferably rich, and more preferably has an overall fuel-to-air equivalent ratio (Φ or ER) greater than 1, greater than 1.5, greater than 2, greater than 3, about 1.5 to about 4.0, about 1.1 to about 3.5, about 2 to about 4.5, about 1.1 to about 3, and greater.

[0123] It is understood that oxygen can be added to the air. Water or steam can also be injected into the air-fuel mixture, or into the air or fuel alone. Approximately 1 to 20% (mol) of water can be injected, approximately 10 to 15% (mol) of water, approximately 5 to 17% (mol) of water, more than 5% (mol) of water, more than 10% (mol) of water, more than 15% (mol) of water, and less than 25% (mol) of water. After oxygen concentration, the combustion air can contain approximately 21% (mol) to 90% (mol) of oxygen. The “air intake” reformers and air intake engines used here also include engines that use air that has been reformed by adding water, oxygen, or both.

[0124] The reciprocating engine 1914 produces synthesis gas by partially burning a predetermined mixture of flare gas and air. The synthesis gas passes through a heat exchanger and flows into a filter, such as a particulate filter.

[0125] After passing through the filter, the synthesis gas flows into a guard bed reactor assembly, which optionally comprises two guard bed reactors. After leaving the guard bed reactor, the synthesis gas flows into a deoxo reactor. The deoxo reactor removes excess oxygen from the reprocessed gas (e.g., synthesis gas).

[0126] This system incorporates a cooling system that uses a cooling fluid, such as cooling water, which is circulated through a cooling line. Other cooling methods, such as direct air cooling, are also envisioned.

[0127] After leaving the deoxo reactor, the synthesis gas flows into a heat exchanger where it is cooled. The treated gas (e.g., synthesis gas) then flows from the heat exchanger to a moisture removal unit (e.g., a water knockout drum, demister, dryer, membrane, cyclone, desiccant, etc.) where moisture is removed. Generally, the synthesis gas leaving the moisture removal unit should contain less than approximately 5%, 2%, 1%, and 0.1% moisture by weight, respectively.

[0128] After leaving the moisture removal unit, the dry synthesis gas enters the synthesis stage 1902. In stage 1902, the dry synthesis gas flows to an assembly that controls the addition of hydrogen-rich gas to the dry synthesis gas from the line. In this way, the ratio of the components of the synthesis gas can be adjusted and controlled to a predetermined ratio. Hydrogen is supplied from the hydrogen separation unit 1939. The ratio-adjusted dry synthesis gas leaves the assembly and flows to the compressor 1932. The compressor 1932 compresses the synthesis gas to an optimal pressure for use in the synthesis unit 1933 (an arbitrary two-stage unit comprising a first reactor unit 1933a and a second reactor unit 1933b), as taught and disclosed herein. The synthesis unit 1933 also comprises a regenerative heat exchanger 1920e.

[0129] The synthesis unit 1933 converts the ratio-adjusted dry synthesis gas into value-added products, such as methanol. The methanol flows into a heat exchanger (i.e., a cooler) and then into the recovery unit 1940. The recovery unit 1940 recovers the condensed methanol and sends it into the line for sale, storage, or further processing.

[0130] Furthermore, the recovery unit 1940 has a line that carries the unreacted gas separated from methanol to a T-connector, from which it is sent to the hydrogen separation unit 1939, the recirculation loop, or both. The recirculation loop is equipped with a compressor and valves for returning methanol to the synthesis unit 1933.

[0131] Step 1902 includes line 1983 for extracting low-water methanol from unit 1933b and sending it to heat exchanger 1920d. Step 1902 also includes line 1987 for removing high-water product from unit 1833b.

[0132] System 1900 is for a gas liquefaction process of by-products from reaction separation. This process uses a two-stage methanol synthesis reactor, with reaction separation performed only in the second stage (Rxtr2) 1933b. The first stage (Rxtr1) 1833a is generally far from equilibrium, and reaction separation is not guaranteed. The example shown in this figure is membrane separation with gas washing. Water (a by-product of methanol production by CO2 hydrogenation) is selectively removed in situ from reactor 1833b (via line 1987), resulting in a water-free gas stream containing mainly unreacted synthesis gas and water-rich washing gas. In this embodiment, the main recirculation loop is not used because the single-pass conversion rate is improved. Furthermore, in this embodiment, the sweep stream (e.g., air in this embodiment) is not regenerated. The membrane reactor can use polymer or ceramic membrane materials that are permeate selectively to water and become the scavenging gas (e.g., air) on the permeate side of the membrane. Removing water shifts the equilibrium to the product side. Since CO2 is converted to CO via a reverse water-gas shift reaction, this approach is also useful for converting CO2 to the more reactive CO. Therefore, this approach is particularly attractive for synthesis gas streams containing a large amount of CO2, such as those produced by partial oxidation. Methanol is condensed from the gas phase in a downstream separation step and mixed with the methanol product stream.

[0133] In embodiments, the system and process of Figure 7 may include one or more devices and processes for reducing the compressor workload. Thus, the system and process of Figure 7 may include or use one or more of the following: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from the standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover most of the compression work, thereby reducing the cost of operating the plant, along with other efficiencies; and (d) using an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressures. These devices and processes for reducing the compressor workload may be used in conjunction with the system and process of Figure 7, for example, as part of the system and process of Figure 7, or as combinations and variations of this association, such as modular, integrated, and combinations thereof.

[0134] In this embodiment, the system and process utilize the reaction separation of by-products. This process uses a two-stage methanol synthesis reactor, with reaction separation performed only in the second stage (Rxtr2). The first stage (Rxtr1) is generally far from equilibrium, and reaction separation is not guaranteed. The example shown in this figure is membrane separation by gas washing. Water (a by-product of methanol production by hydrogenation of CO2) is selectively removed in situ from the reactor, resulting in a water-reduced gas stream containing mainly unreacted synthesis gas and water-rich scavenging gas. Compared to other systems, such as those shown in Figure 3, the single-pass conversion rate is improved, and a main recirculation loop is not required, and preferably not required. Furthermore, compared to other embodiments, such as those shown in Figure 6, regeneration of the sweep stream (e.g., air in this embodiment) may not be required, and preferably not required. The membrane reactor can use polymer or ceramic membrane materials that are permeable selective to water and permeable selective to scavenging gas (e.g., air) on the membrane permeation side. Removing water shifts the equilibrium to the product side. Because CO2 is converted to CO via a reverse water-gas shift reaction, this approach is also useful for converting CO2 to the more reactive CO. Therefore, this approach is particularly attractive for synthesis gas streams rich in CO2, such as those produced by partial oxidation. Methanol is condensed from the gas phase in a downstream separation step and mixed with the methanol product stream. This system and process may include one or more devices or processes that reduce the workload on the compressor.

[0135] Referring to Figure 8, embodiments of a system and method for converting flare gas into a value-added product are shown. System 800 comprises a reforming step 801 and a synthesis step 802. System 800 includes an air intake 810 that supplies air to a compressor 811 that compresses air. The compressed air is fed through a heat exchanger 820a to a mixer 813. The system has a flare gas intake 884. The flare gas flows through a heat exchanger 820b to the mixer 813. The mixer 813 supplies a predetermined mixture of air and flare gas to a reformer 814, which is a reciprocating engine, as disclosed and described in more detail herein.

[0136] The fuel-air mixture formed in mixer 813 is preferably rich, and more preferably has an overall fuel-to-air equivalent ratio (Φ or ER) greater than 1, greater than 1.5, greater than 2, 3, about 1.5 to about 4.0, about 1.1 to about 3.5, about 2 to about 4.5, about 1.1 to about 3, and greater.

[0137] It is understood that oxygen can be added to the air. Water or steam can also be injected into the air-fuel mixture, or into the air or fuel alone. Approximately 1 to 20% (mol) of water can be injected, approximately 10 to 15% (mol) of water, approximately 5 to 17% (mol) of water, more than 5% (mol) of water, more than 10% (mol) of water, more than 15% (mol) of water, and less than 25% (mol) of water. After oxygen concentration, combustion air can contain approximately 21% (mol) to 90% (mol) of oxygen. The “air intake” reformers and air intake engines used here also include engines that use air that has been reformed by adding water, oxygen, or both.

[0138] The reciprocating engine 814 partially combusts a predetermined mixture of flare gas and air to form synthesis gas. The synthesis gas passes through heat exchangers 820a and 820b and flows into a filter 815, which is, for example, a particulate filter.

[0139] After passing through filter 815, the synthesis gas flows to guard bed reactor assembly 816, which optionally comprises two guard bed reactors 816a and 816b. The guard bed reactor 816 contains materials such as a catalyst to remove contaminants and other substances from the synthesis gas that could adversely affect, hinder, or contaminate subsequent equipment or processes in the system. For example, the guard bed reactor 816 may contain a catalyst or other material to remove sulfur (e.g., iron sponge, zinc oxide, or similar) or halogenated compounds.

[0140] After exiting the guard bed reactor 816, the synthesis gas flows to the deoxo reactor 817. In the deoxo reactor 817, excess oxygen is removed from the reprocessed gas (e.g., synthesis gas) by oxidizing the flammable compounds in the mixture, such as methane, carbon monoxide, and hydrogen, and the oxygen is converted to water. The catalyst for the deoxo reaction is platinum, palladium, and other active materials supported on alumina or other catalyst support material.

[0141] System 800 includes a cooling system 850 that uses a cooling fluid, such as cooling water, which flows through a cooling line such as 851. Other cooling means, such as direct air cooling, are also envisioned.

[0142] After exiting the deoxo reactor 817, the synthesis gas flows into the heat exchanger 820c, where it is cooled. The treated gas (e.g., synthesis gas) then flows from the heat exchangers 820f and 820c into a moisture removal unit 818, such as a water knockout drum, demister, dryer, membrane, cyclone, desiccant, or similar, where moisture is removed from the synthesis gas. Generally, the synthesis gas exiting unit 818 should contain less than approximately 5%, 2%, 1%, and 0.1% moisture by weight.

[0143] After leaving unit 818, the dry synthesis gas enters the synthesis stage 802. In stage 802, the dry synthesis gas flows to assembly 830. Assembly 830 adds hydrogen-rich gas from line 831 to the dry synthesis gas in a controlled manner. In this way, the ratio of the synthesis gas components can be adjusted and controlled to a predetermined ratio. Hydrogen is supplied from hydrogen separation unit 839. The ratio-adjusted dry synthesis gas leaves assembly 830 and flows into compressor 832. Compressor 832 compresses the synthesis gas to an optimal pressure for use in synthesis unit 833, as taught and disclosed herein. Preferably, synthesis unit 833 is a two-stage unit comprising an optional first reactor unit 833a and a second reactor unit 833b. Synthesis unit 833 also comprises a regenerative heat exchanger 820e.

[0144] The synthesis unit 833 converts the ratio-adjusted dry synthesis gas into methanol, a value-added product. The methanol flows into the heat exchanger (i.e., condenser) 820d. The methanol flows into the recovery unit 840. The recovery unit 840 recovers the condensed methanol and sends it to line 841 for sale, storage, or further processing.

[0145] Generally, synthesis gas is compressed to pressures of about 15 to about 100 bar, preferably about 30 to 50 bar, about 25 to about 80 bar, at least about 10 bar, at least about 25 bar, at least about 50 bar, and above and below. The temperature of the pressurized synthesis gas is regulated to temperatures of about 150°C to about 350°C, preferably about 250°C, about 200°C to about 300°C, about 250°C to about 375°C, above 125°C, above 150°C, above 200°C, above 250°C, above 350°C, below 400°C, and above and below. The pressure and temperature controlled synthesis gas is supplied to reactors to convert the synthesis gas into more useful, easily transportable, and economically available products such as methanol, ethanol, ammonia, dimethyl ether, FT liquids, and other fuels and chemicals. In a preferred embodiment, methanol is produced from synthesis gas via a hydrogenation reaction of CO, a hydrogenation reaction of CO2, and a reverse steam shift reaction, using an actively cooled reactor such as a heat exchange reactor or a boiling water reactor and a copper-containing catalyst such as Cu / ZnO / Al2O3.

[0146] Generally, in preferred embodiments, the characteristic length scale of the reactors used in this system is sufficiently small (e.g., microchannels or minichannels) and can be molded into unprecedented shapes and topologies using new 3D printing techniques for metals and other high-temperature materials, enabling compact packaging and precise control of reaction conditions. Other strategies for enhancing downstream synthetic reactions can also be explored, such as selectively removing products from the reactor in situ or in close bond to shift equilibrium-limiting reactions to higher conversion rates. This process enhancement can minimize the need for large-scale recirculation flows and allow reactions to proceed under milder conditions (e.g., low pressure), thereby increasing process safety margins and providing other advantages.

[0147] Generally, the H2 / CO ratio of synthesis gas produced by an engine can be adjusted to suit the downstream conversion process. For example, in methanol synthesis and Fischer-Tropsch (FT) synthesis, the ideal H2 / CO ratio is 2-3. In ammonia synthesis and hydrogen production, the highest possible H2 / CO ratio is desirable, and this ratio can be increased, for example, by adding steam to accelerate the water-gas conversion reaction. In ammonia and hydrogen production, CO is not required in the downstream synthesis. Therefore, the by-products of CO and CO2 can be recovered, sequestered, stored, or used for other purposes.

[0148] Furthermore, the recovery unit 840 has a line that carries the gas separated from methanol to a T-shaped connector 835, from which it is sent to the hydrogen separation unit 839, the recirculation loop, or both. The recirculation loop is equipped with a compressor 834 and a valve 838 for returning methanol to the synthesis unit 833. Hydrogen separation can be performed in the hydrogen separation unit 839 by membrane separation or pressure swing adsorption (PSA), etc.

[0149] The remaining gas after hydrogen separation is sent through loop 890 and heat exchanger 820f to turboexpander 891, where the gas is exhausted. The turboexpander generates power to supplement part of the compressor's power requirements.

[0150] In one embodiment of the system in Figure 8, the reformer 814 is a spark-ignition (Otto cycle) reciprocating engine. This system can be suitably operated as shown in the TS diagram of Figure 13. The reference points (numbered 81, 82, 83, 84, 85, 86, 87, 88, 89 in Figure 8) correspond to the process conditions, i.e., state points, at their respective locations in the system in Figure 8, and these process conditions are indicated by the corresponding reference points in Figure 13. The line from state point 84a' to 84b' represents the decrease in compression ratio that occurs in response to a more reactive flare gas fuel. State point 85b relates to the synthesis gas exiting the synthesis gas reformer after turbocharger expansion. The expansion from 85 to 85b occurs within the turbocharger. The specific entropy at the start of this process is at points 81, 82 (6.9 kJ / kg°C), and the final specific entropy point of this process is at point 89 (6.95 kJ / kg°C). Therefore, the difference between the initial and final specific entropy is 0.05 kJ / kg°C.

[0151] In one embodiment of the system in Figure 8, the reformer 814 is a compression-ignition (diesel cycle) reciprocating engine. This system can be suitably operated as shown in the TS diagram of Figure 14. The reference points (numbered 81, 82, 83, 84, 85, 86, 87, 88, 89 in Figure 8) correspond to the process conditions, i.e., state points, at their respective locations in the system in Figure 8, and these process conditions are indicated by the corresponding reference points in Figure 14. The line from state point 84a' to 84b' represents the decrease in compression ratio that occurs in response to a more reactive flare gas fuel. State point 85b relates to the synthesis gas exiting the synthesis gas reformer after turbocharger expansion. The expansion from 85 to 85b occurs within the turbocharger. The specific entropy at the start of this process is at points 81, 82 (6.9 kJ / kg°C), and the final specific entropy point of this process is at point 89 (6.95 kJ / kg°C). Therefore, the difference between the initial and final specific entropy is 0.05 kJ / kg°C.

[0152] Preferably, embodiments of the spark-ignition (Otto cycle) and compression-ignition (Diesel cycle) reciprocating engines of the systems and processes of Figure 8 include one or more compressor-reducing devices and processes. Thus, the systems and processes of Figure 8 include or can be used one or more of the following: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from the standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover most of the compression work, thereby reducing the cost of operating the plant, along with other efficiencies; and (d) using an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressures. These compressor-reducing devices and processes can be used in conjunction with the systems and processes of Figure 8, for example, as part of the systems and processes of Figure 8, or as combinations and variations of this association, such as modular, integrated, and combinations thereof. Examples

[0153] The following are examples illustrating various embodiments of systems, apparatus, and processes for the conversion of waste fuel, such as flare gas. These embodiments are illustrative and may be speculative and should not be considered to limit or otherwise restrict the scope of the invention.

[0154] Example 1

[0155] Referring to Figure 10, an embodiment of a turboexpander-heat exchanger system for reducing the workload of a compressor required in a reformer-based hydrocarbon processing system, such as a gas liquefaction system, is shown. System 1000 has three stages 1100, 1200, and 1300. Each stage has a compressor-turbine assembly and a heat exchanger. Stage 1100 has a compressor 1101 driven by a turbine 1102 and a heat exchanger 1103. Stage 1200 has a compressor 1201 driven by a turbine 1202 and a heat exchanger 1203. Stage 1300 has a compressor 1301 driven by a turbine 1302 and a heat exchanger 1303. During operation, product 600, which is typically exhaust gas separated by a gas liquefaction system, is supplied to stage 1300. Product 600 can have a pressure of 50 bar or more and a temperature of less than 250°C. Product 600 flows through stages 1300, 1200, and 1100, as shown in the figure. Reactant 500, which is the material supplied by the reformer's output, e.g., synthesis gas, is supplied to stage 1100 and flows through stages 1200 and 1300, as shown in the figure, exiting at around 250°C and 50 bar. Graph 1000b shows the pressure and pressure changes as product 600b and reactant 500b pass through stages 1100a, 1200a, and 1300a. Graph 1000c shows the temperature and temperature changes of product 600c and reactant 500c as they pass through stages 1100a, 1200a, and 1300a. Points 1 and 5 on the axis of graph 1000b represent pressure in bar units.

[0156] The embodiment in Figure 10 has three stages, but one, two, four, five, or more stages are possible. System 1000 can be an integral part of a gas liquefaction system, such as the systems in Figures 3, 4, 6, 7, or 8. Alternatively, it can be a separate module (e.g., skid-mounted) operably connected to the gas liquefaction system (e.g., pipes, valves, control systems).

[0157] Example 2

[0158] In one embodiment, the system 100 in Figure 3 comprises a turboexpander-compressor-heat exchanger system, for example, shown as a compressor 132 in Figure 10. In this embodiment, the product 600 in Figure 10 is the exhaust gas from the hydrogen separation unit 139. The reactant 500 in Figure 10 is the ratio-adjusted dry reprocessed gas (e.g., synthesis gas) exiting the assembly 830.

[0159] Example 2

[0160] In one embodiment of system 100 in Figure 3, high-pressure liquid and gaseous product streams are expanded via a valve (or back pressure regulator) in a Joule-Thomson (substantially isothermal and isobaric) expansion process. In this configuration, auxiliary power is required for compression because there is insufficient power for self-sufficiency.

[0161] Example 4

[0162] In one embodiment, the system 1600 in Figure 4 comprises a turboexpander-compressor-heat exchanger system, such as the compressor 1632 shown in Figure 10. In this embodiment, the product 600 in Figure 10 is the exhaust gas from the hydrogen separation unit 1639. The reactant 500 in Figure 10 is the ratio-adjusted dry reprocessing gas (e.g., synthesis gas) supplied to the compressor 1632.

[0163] Example 5

[0164] In one embodiment, the system 800 in Figure 8 comprises a turboexpander-compressor-heat exchanger system, for example, shown as a compressor 832 in Figure 10. In this embodiment, the product 600 in Figure 10 is the exhaust gas from the hydrogen separation unit 839. The reactant 500 in Figure 10 is the ratio-adjusted dry reprocessing gas (e.g., synthesis gas) exiting the assembly 830. In this embodiment, the turboexpander 891 may not be used, but it may still be used for excess exhaust gas that is not used in the operation of the turboexpander-compressor-heat exchanger in Figure 10.

[0165] Example 6

[0166] In embodiments of the modular systems and methods of the type shown in Figures 3, 4, 6, 7, 8, or 15, the system and method utilize a nominal air-intake engine having means for producing pressurized synthesis gas under rich conditions. This synthesis gas may have a pressure greater than 1 bar, greater than 2 bar, greater than 3 bar, greater than 4 bar, greater than 5 bar, about 2 bar to about 5 bar, or about 3 bar to about 5 bar when discharged from the engine reformer. In this system, for example, the temperature of the synthesis gas when it enters the compressor is about 50°C, while the temperature is between 40°C and 60°C, or higher or lower.

[0167] Example 7

[0168] In embodiments of the modular systems and methods of the type shown in Figures 3, 4, 6, 7, 8, or 15, the system and method utilize a nominal air intake engine having means for producing pressurized synthesis gas under rich conditions. Furthermore, the system includes means for reducing nitrogen content, such as an oxygen enrichment unit, an air separation unit, or a nitrogen removal unit for removing nitrogen from the synthesis gas. In this system, nitrogen is reduced, for example, by 10%, 20%, or more.

[0169] Example 8

[0170] In embodiments of the modular systems and methods of the type shown in Figures 3, 4, 6, 7, 8, or 15, the system and method utilize a nominal air-intake engine having means for operating under rich conditions and producing pressurized synthesis gas. The system further includes a turbo-expander or expansion turbine, such as a turbine drive shaft, which is expanded using the excess high-pressure gas to produce work. In this system, for example, the turbine inlet pressure is approximately 50 bar and the turbine outlet pressure is approximately 3 bar.

[0171] Example 9

[0172] In embodiments of the modular systems and methods of the type shown in Figures 3, 4, 6, 7, 8, or 15, the system and method utilize a nominal air intake engine having means for producing pressurized synthesis gas, operating under rich conditions. Furthermore, the system includes an enhanced synthesis loop for methanol synthesis at lower pressures, such as for the reaction separation of products or by-products. In this system, for example, the conversion rate of single-pass methanol synthesis is increased by 5%, 10%, or more or less.

[0173] Example 10

[0174] In one embodiment, the exhaust back pressure of the engine reformer is increased to reduce the compression requirements of the downstream synthesis gas. The exhaust pressure is expected to be reasonably increased from a typical value near atmospheric pressure (approximately 1 bar) to 5 bar or more. Given that the downstream synthesis pressure is typically set to 50 bar, increasing the exhaust back pressure of the engine reformer reduces the overall pressure ratio required to compress the synthesis gas, thereby reducing the compressor's work (kJ / kg) or power (kW). Since the engine reformer is self-supporting, increasing the exhaust back pressure does not directly affect the upstream compression work. However, increasing the back pressure affects the engine's volumetric efficiency and the engine's net traction force. Considering these trade-offs, an optimal back pressure of an intermediate value is suggested. The back pressure is determined by the flow resistance of the downstream process. Various improvements to the engine reformer (e.g., turbocharging the engine reformer inlet air, changing engine valve timing to reduce or eliminate valve overlap) are expected to maintain acceptable engine performance as the exhaust back pressure increases.

[0175] Example 11

[0176] In one embodiment, reaction separation is used to selectively remove reaction products (or by-products) in order to shift the equilibrium to the product side according to Le Chatelier's principle. The product (e.g., methanol) or by-product (e.g., water) is removed from the synthesis reactor in situ or in a tightly coupled manner. Tight coupling means separation within the loop without expensive and energy-intensive downstream separation. Separation can be carried out by adsorption, absorption, membrane separation, distillation, etc. Reaction separation enables good single-pass conversion and reduces or eliminates the need for energy-intensive and capital-intensive separation and recirculation loops. More importantly, from the perspective of this solution, reaction separation eliminates the need to increase the reactor pressure, and as a result, the compression work required for the process can be reduced. For adsorption separation, various adsorbents selective for methanol or water (e.g., silica alumina) and various adsorption devices (e.g., packed bed, moving bed, moving bed simulator) can be used. In absorption separation, various absorbents (e.g., tetraethylene glycol dimethyl ether, commonly TGDE or Tetragrime, or squalane) can be used with various absorption devices (e.g., dropping beds, bubble columns). In membrane separation, various polymer materials (e.g., sulfonated tetrafluoroethylene-based fluoropolymer copolymers such as Nafion®) or ceramic materials (e.g., zeolites) can be used to separate and remove methanol or water in various membrane module configurations (e.g., hollow fiber bundles, spiral types, plate types). Optionally, membrane separation can be performed using a sweep stream of gas (e.g., air) or liquid (e.g., TGDE) on the permeate side. Reactive distillation (RD) can also be used to selectively remove methanol from reactants based on differences in volatility. In any RD, various improved (e.g., split-wall column distillation) or hybrid (e.g., extractive distillation with TGDE, etc.) distillation approaches can be used.

[0177] Example 12

[0178] In one embodiment, reaction separation is used to selectively remove reaction products (or by-products) in order to shift the equilibrium to the product side according to Le Chatelier's principle. The product (e.g., methanol) or by-product (e.g., water) is removed from the synthesis reactor in situ or in a tightly coupled manner. Tight coupling means separation within the loop without expensive and energy-intensive downstream separation. Separation can be carried out by adsorption, absorption, membrane separation, distillation, etc. Reaction separation enables good single-pass conversion and reduces or eliminates the need for energy-intensive and capital-intensive separation and recirculation loops. More importantly, from the perspective of this solution, reaction separation eliminates the need to increase the reactor pressure, and as a result, the compression work required for the process can be reduced. For adsorption separation, various adsorbents selective for methanol or water (e.g., silica alumina) and various adsorption devices (e.g., packed bed, moving bed, moving bed simulator) can be used. In absorption separation, various absorbents (e.g., tetraethylene glycol dimethyl ether, commonly TGDE or Tetragrime, or squalane) can be used with various absorption devices (e.g., dropping beds, bubble columns). In membrane separation, various polymer materials (e.g., sulfonated tetrafluoroethylene-based fluoropolymer copolymers such as Nafion®) or ceramic materials (e.g., zeolites) can be used to separate and remove methanol or water in various membrane module configurations (e.g., hollow fiber bundles, spiral types, plate types). Optionally, membrane separation can be performed using a sweep stream of gas (e.g., air) or liquid (e.g., TGDE) on the permeate side. Reactive distillation (RD) can also be used to selectively remove methanol from reactants based on differences in volatility. In any RD, various improved (e.g., split-wall column distillation) or hybrid (e.g., extractive distillation with TGDE, etc.) distillation approaches can be used.

[0179] Example 13

[0180] Small-scale plants target an inlet gas flow rate of 3,000,000 standard cubic feet / day (SCFD). The size of such plants varies from 50,000 SCFD to 15,000,000 SCFD. The plants are assembled in one or more modularly interconnected skids or containers at a central manufacturing plant before being installed on-site. The system consists of a small number of modules that, when connected on-site, form an integrated system. Modular assembly allows for adaptation to various inlet gas supply volumes, minimizing on-site labor and enabling application in remote locations. The modular nature further enhances the flexibility of deploying and redeploying these assets, reduces initial capital expenditure and project financial risk, allows process output to match flare gas supply, and shortens time to market by enabling parallel manufacturing and on-site preparation of modules. This plant has one or more of the following features: (a) reducing the amount of nitrogen; (b) increasing the engine back pressure from the standard 1 or 2 bar to a maximum of 5 bar; (c) using a turbo expander to recover a large portion of the compression work and reduce the plant's operating costs; and (d) using an enhanced synthesis loop to achieve acceptable methanol synthesis at lower overall pressures.

[0181] Example 14

[0182] In embodiments of the system including the components described in Examples 10 and 12, a complete system that is balanced in terms of mass flow rate and energy is shown in Figure 15.

[0183] Referring to Figures 15 and 15A through 15C, schematic diagrams of the system and process systems utilizing embodiments 10 and 13 in the gas liquefaction system 1400 are shown. The system and process 1400 comprises a reformer subsystem 1440, a methanol subsystem 1460, and a turboexpander (e.g., turbocompressor) subsystem 1480. An enlarged view of the reformer subsystem 1440 (and other components) is shown in Figure 15A. An enlarged view of the methanol subsystem 1460 is shown in Figure 15B. An enlarged view of the turboexpander subsystem 1480 is shown in Figure 15C. (Lines or pipes A, B, C, and D provide fluid flow and fluid communication between the three subsystems.)

[0184] Referring to Figure 15A, the reformer subsystem 1440 has an air intake 1445 for receiving an airflow and a hydrocarbon gas intake 1446 (e.g., flare gas intake) for receiving a hydrocarbon gas flow (e.g., flare gas). The reformer subsection comprises a turbocharger 1441, an air preheater 1442, an air intake reformer 1449, a mixer 1444, and a desulfurization unit 1447. Furthermore, a deoxo unit 1433 is shown on the line from the reformer subsystem 1440 to the turboexpander subsystem 1480. Arrows indicate the direction of flow in the system and process.

[0185] Referring to Figure 15B, methanol synthesis subsystem 1460 has a compressor 1461, a mixer 1462, a CO2 membrane unit 1463, and a hydrogen membrane unit 1464. Subsystem 1460 has a reactor unit 1469 and a heat exchanger 1474. Subsystem 1460 further has heat exchangers 1471, 1472, a methanol condenser 1465, and a methanol deaerator 1466. This system has an exhaust gas oxidation unit 1467 for the supply air 1468 and an associated heat exchanger 1475. System 1460 has a compressor 1473, a heat exchanger 1474, and a mixer 1470. The system has arrows indicating the direction of flow in the system and process.

[0186] Referring to Figure 15C, the turbo expander subsystem 1480 comprises a heat exchanger 1481, a heat exchanger 1481, and a knockout drum 1483. The subsystem 1480 further comprises a compressor 1484 and a turbine 1485. The turbine (turbo expander) 1485 also comprises a balance valve 1486 and a mixer 1487. The subsystem 1480 comprises a heat exchanger 1488 and a water knockout drum 1439. The subsystem 1480 comprises a compressor 1490 and a turbine (turbo extractor) 1493, to which a balance valve 1491 and a heat exchanger 1492 are associated. The subsystem 1480 also has a splitter 1494, a heat exchanger 1495, a heat exchanger 1496, and a drain drum 1497. The system has arrows indicating the direction of flow in the system and process.

[0187] This system utilizes the high-pressure flow from the chemical process and the thermal energy (heat) available in the process to generate axial work via a turbo expander. This axial work drives the initial compression system for the incoming process fluid. Additional turbine work is generated by reheating between stages on the turbine side. Intercooling between compression stages reduces the amount of work required for compression. Separate bypass (wastegate) control valves are used to control the turbocompressor. The pressure at the outlet of the initial compression system matches the pressure at the outlet of the retained gas (exhaust gas) from the hydrogen separation unit, allowing the flow to be integrated into a single compressor and pressurized to the pressure required for the methanol process. For a system that typically processes 58 kg / h of hydrocarbon gas, this turbocompressor system uses an external axial output of 98 kW, such as an electric motor. e From 60kW e The load on the cooler will be reduced to 258 kW. The condensation temperature of the process fluid will be raised from 30°C to 60°C, and as a result the cooler load will be reduced to 258 kW. th From 20kW th It will be reduced to [amount].

[0188] It is not necessary to provide or explain the theories underlying any novel and groundbreaking production rates, performance, or other beneficial functions or properties that are subject to or related to the embodiments of the present invention. However, in order to further develop the technology in this important field, particularly in the field of hydrocarbon exploration, production, and downstream transformation, various theories are presented herein. These theories, while presented herein, do not limit, restrict, or narrow the scope of protection granted to the invention as described in the claims unless expressly stated otherwise. These theories are neither required nor practiced in order to utilize the present invention. Furthermore, it is understood that the present invention may lead to new, previously unknown theories that describe the operation, activity, resource production, chemical, and functional characteristics of embodiments of the methods, articles, materials, apparatus, and systems of the present invention. Moreover, such subsequently developed theories do not limit the scope of protection granted to the present invention.

[0189] Various embodiments of the apparatus, systems, activities, methods, and operations described herein, in addition to the illustrated embodiments and disclosed herein, may be used together with, in, or by them in various processes, industries, and operations. Various embodiments of the apparatus, systems, methods, activities, and operations described herein may be used in combination with other processes, industries, and operations that may be developed in the future. They may also be used in combination with existing processes, industries, and operations that may be partially modified based on the teachings herein. Furthermore, they may be used in combination with other types of gas recovery and value stabilization systems and methods. Moreover, various embodiments of the apparatus, systems, activities, methods, and operations described herein can be used with each other in various different combinations. Thus, for example, the configurations described in various embodiments herein can be used with each other. For example, the components of an embodiment having A, A', and B and the components of an embodiment having A', C, and D can be used alone or with each other in various combinations according to the teachings herein, such as A, C, D, and A, A', C, D, and A', B, and D. Therefore, the scope of protection granted to the present invention should not be limited to specific embodiments, configurations, or arrangements described in specific embodiments, examples, or embodiments in specific figures.

[0190] The invention can be embodied in forms other than those specifically disclosed herein, without departing from its spirit or substantial features. The embodiments described herein are considered in all respects only as illustrative and not limiting.

Claims

1. A method for converting a gas into a liquid final product, a. A process for receiving a flow of hydrocarbon-based fuel source whose composition is mainly gaseous hydrocarbons and inert gases from a supply source, b. A step of partially oxidizing the fuel source in an air-intake rich-burn reciprocating engine operated under rich fuel conditions to produce a synthesis gas mixture having an H2 / CO ratio suitable for the synthesis of the final liquid product, c. A step of performing a step of reducing the workload of a synthesis gas compressor while maintaining the pressure of the downstream synthesis reactor system, wherein the reduction in the workload of the synthesis gas compressor compensates for the energy required to operate the synthesis gas compressor. d. A step of flowing the synthesis gas mixture into the downstream synthesis reactor system, where the liquid final product is produced from the synthesis gas mixture, Includes, A method for reducing the workload of the synthesis gas compressor, wherein the step of flowing a gas stream to a turbo expander.

2. The method according to claim 1, wherein the pressure in the downstream synthesis reactor system is at least 50 bar.

3. The method according to claim 1, wherein the step of reducing the workload of the synthesis gas compressor further includes increasing the back pressure of the air intake rich burn reciprocating engine.

4. The method according to claim 3, wherein the back pressure increases to 5 bar.

5. The method according to claim 1, wherein the pressure of the downstream synthesis reactor system is 25 bar to 80 bar.

6. The method according to claim 1, wherein the turbo expander has a heat exchanger, thereby constituting a turbo expander-heat exchanger system.

7. The method according to claim 1, wherein the step of reducing the workload of the synthesis gas compressor further includes reaction, separation, and synthesis.

8. The method according to any one of claims 1 to 7, wherein the air intake rich-burn reciprocating engine is a variable compression ratio engine.

9. The method according to any one of claims 1 to 7, wherein the air intake rich-burn reciprocating engine is a compression ignition engine.

10. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is a spark ignition engine.

11. A system for converting gas into a liquid final product, a. An inlet port for receiving a flow of a hydrocarbon-based fuel source whose composition is mainly gaseous hydrocarbons and inert gases from a supply source, b. A H configured to operate under rich fuel conditions, which partially oxidizes the fuel source to be suitable for the synthesis of the final liquid product. ２ An air intake rich-burn reciprocating engine that is fluid-communicated with an inlet port that produces a synthesis gas mixture having a CO ratio, c. A synthesis gas compressor configured to receive the flow of the synthesis gas mixture from the air intake rich burn reciprocating engine, d. Means for reducing the workload of the synthesis gas compressor while maintaining the pressure of the downstream synthesis reactor system, e. The downstream synthesis reactor system is configured to receive the flow of the synthesis gas mixture from the synthesis gas compressor and thereby produce the liquid final product from the synthesis gas mixture, Equipped with, A system in which the means for reducing the workload of the synthesis gas compressor includes a turbo expander configured to compensate for the energy required to operate the synthesis gas compressor.

12. The system according to claim 11, wherein the pressure of the downstream synthesis reactor system is 50 bar or more.

13. The system according to claim 11, wherein the pressure of the downstream synthesis reactor system is 25 bar to 80 bar.

14. The system according to claim 11, further comprising means for reducing the amount of nitrogen.

15. The system according to claim 11, wherein the means for reducing the workload of the synthesis gas compressor has increased back pressure of the air intake rich burn reciprocating engine.

16. The system according to claim 15, wherein the increased back pressure is a maximum of 5 bar.

17. The system according to claim 15, wherein the increased back pressure is greater than 2 bar.

18. The system according to claim 11, wherein the turbo expander has a heat exchanger, thereby constituting a turbo expander-compressor-heat exchanger system.

19. The system according to claim 18, wherein the turbo expander-compressor-heat exchanger system is configured in three stages.

20. The system according to claim 18, wherein the turbo expander-compressor-heat exchanger system comprises a compressor-turbine assembly.

21. The system according to claim 18, wherein the turbo expander-compressor-heat exchanger system is configured in two stages, each stage comprising a compressor, a turbine, and a heat exchanger.

22. The system according to claim 21, wherein the turbo expander-compressor-heat exchanger system is configured in three stages, each stage comprising a compressor, a turbine, and a heat exchanger.

23. The system according to claim 11, wherein the means for reducing the workload of the synthesis gas compressor includes a reaction-separation-synthesis loop.

24. The system according to any one of claims 11 to 23, wherein the air intake rich-burn reciprocating engine is a variable compression ratio engine.

25. The system according to any one of claims 11 to 23, wherein the air intake rich-burn reciprocating engine is a compression ignition engine.

26. The system according to any one of claims 11 to 23, wherein the air intake rich-burn reciprocating engine is a spark-ignition engine.

27. The method according to any one of claims 1 to 7, wherein the fuel source is flare gas.

28. The system according to any one of claims 11 to 23, wherein the fuel source is flare gas.

29. The system according to claim 11, wherein the air intake rich-burn reciprocating engine is a compression-ignition engine including a diesel cycle engine, or a premixed compression-ignition engine.

30. The system according to claim 11, wherein the air intake rich-burn reciprocating engine is a spark-ignition engine including an Otto cycle.

31. The system according to claim 11, wherein the air intake rich-burn reciprocating engine is an opposed-piston, free-piston, linear internal combustion engine.

32. The air intake rich-burn reciprocating engine is a crankshaft-driven opposed-piston internal combustion engine, and is equipped with a crankshaft phaser that rotates the phase of one piston relative to the phase of the other piston to change the overall compression ratio, according to claim 11.

33. The method according to any one of claims 1 to 7, wherein the air intake rich-burn reciprocating engine is a conventional spark-ignition reciprocating engine that achieves a variable "effective" compression ratio by utilizing a camshaft phaser that rotates the intake camshaft and exhaust camshaft so as to act on the opening and closing of valves.

34. The method according to any one of claims 1 to 7, wherein the air intake rich-burn reciprocating engine is a conventional spark-ignition reciprocating engine that achieves a variable "effective" compression ratio by utilizing a valve train with variable lift and / or variable duration to act on the opening and closing of the valves.

35. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine comprises a multilink system instead of a conventional connecting rod that rotates the crankshaft, and an actuator motor changes the endpoint of the multilink system.

36. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is a two-stroke engine.

37. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is a four-stroke engine.

38. The method according to any one of claims 1 to 7, wherein the engine speed is varied along with the engine compression ratio to achieve desired combustion and desired exhaust gas composition.

39. The method according to any one of claims 1 to 7, wherein the air temperature in the inlet manifold is varied along with the engine compression ratio to achieve a desired rich burn combustion and a desired exhaust gas composition.

40. The method according to any one of claims 1 to 7, wherein the air pressure in the inlet manifold, which defines the boost level, is varied in conjunction with the engine compression ratio to achieve a desired rich burn combustion and a desired exhaust gas composition.

41. The method according to any one of claims 1 to 7, wherein steam or hydrogen is added to the incoming air or fuel, and the amount of the addition is varied along with the engine compression ratio to achieve a desired rich burn combustion and a desired exhaust gas composition.

42. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is operated under an ER of at least 1.

5.

43. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is operated under an ER of at least about 2.

44. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is operated under an ER of at least about 2.

5.

45. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is operated under an ER of at least about 3.

46. The method according to any one of claims 1 to 7, wherein the air intake rich burn reciprocating engine is operated under an ER of at least about 2.

5.

47. The method according to any one of claims 1 to 7, wherein the compression ratio of the air intake rich burn reciprocating engine is controlled between 8:1 and 14:

1.

48. The method according to any one of claims 1 to 7, wherein an integrated heat exchanger, a compression system component, and a heat exchanger are combined downstream of the air-intake rich-burn reciprocating engine to prepare synthesis gas for the downstream synthesis reactor.

49. The method according to any one of claims 1 to 7, wherein a cloud-based remote monitoring system, including AI-trained anomaly detection, dynamically monitors changes in variable valve timing and evaluates and responds to anomalies in the fuel supply.

50. CO ２ From an e-life cycle assessment perspective, when produced from flare gas, the amount of CO2 per kg of final product (in this case, liquid methanol) is approximately 40 kg CO2 compared to baseline liquid methanol production from pipelined natural gas. ２ Negative CO of e ２ The method according to any one of claims 1 to 7, which results in the emission of e.

51. When produced from flare gas and replacing equivalent kg of methanol from pipelined natural gas, the resulting negative CO ２ The emissions are approximately 70 kg CO2 per 1 kg of final product (methanol). ２ The method according to any one of claims 1 to 7, wherein e.

52. When produced from flare gas and replacing the equivalent kg of baseline methanol from coal gasification, the resulting negative CO ２ The emissions are approximately 130 kg CO2 per kg of final product (methanol). ２ The method according to any one of claims 1 to 7, wherein e.

53. The method according to any one of claims 1 to 7, wherein the final liquid product comprises methanol.

54. The method according to any one of claims 1 to 7, wherein the final liquid product comprises a material selected from the group consisting of ethanol, ammonia, dimethyl ether, and F-T liquid.

55. The method according to any one of claims 1 to 7, wherein the fuel source is flare gas from a hydrocarbon well.

56. The method according to any one of claims 1 to 7, wherein the fuel source is flare gas from an oil well.

57. The method according to any one of claims 1 to 7, wherein the fuel source is flare gas from an unconventional oil well.

58. The method according to any one of claims 1 to 7, wherein the fuel source is flare gas, and the flare gas is selected from the group consisting of petrochemical processing, refining, landfill, wastewater treatment, and livestock farming.

59. The method according to any one of claims 1 to 7, wherein the flow rate of the fuel source is approximately 50,000 scfd to approximately 30,000,000 scfd.

60. The method according to any one of claims 1 to 7, wherein the flow rate of the fuel source is approximately 500,000 scfd to approximately 20,000,000 scfd.

61. The method according to any one of claims 1 to 7, wherein the flow rate of the fuel source is approximately 600,000 scfd to approximately 15,000,000 scfd.

62. The method according to any one of claims 1 to 7, wherein the flow rate of the fuel source is approximately 700,000 scfd to approximately 10,000,000 scfd.

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