A method for generating hydrogen and oxygen streams and supplying them to a reverse water-gas shift reactor.

Abstract

A method for generating hydrogen and oxygen streams and sending the hydrogen and oxygen streams to a reverse water-gas shift reactor is described, comprising: supplying a water stream to an electrolytic system configured to form a hydrogen stream at a first pressure and an oxygen stream at a second pressure; and sending the hydrogen stream, carbon dioxide stream, and oxygen stream to a reverse water-gas shift reactor, wherein the first pressure is lower than the second pressure.

Description

Technical Field

[0001] The present invention relates to a method for generating a hydrogen stream and an oxygen stream and sending the hydrogen stream and the oxygen stream to a reverse water gas shift reactor.

Background Art

[0002] It is known to produce liquid hydrocarbons by performing a Fischer-Tropsch reaction on synthesis gas containing hydrogen and carbon monoxide. In order to increase the carbon monoxide content of the gas supplied to the Fischer-Tropsch reaction to a preferred level, it is useful to subject a carbon dioxide gas stream to a reverse water gas shift reaction with hydrogen to convert at least a portion of the carbon dioxide and hydrogen to carbon monoxide and water.

[0003] Reverse water gas shift reactors are known. Such a reactor comprises a reverse water gas shift vessel comprising a burner and optionally a fixed bed of a reverse water gas shift catalyst. The reactor is supplied with a hydrogen, carbon dioxide, and an oxygen stream that burns a portion of the hydrogen, thereby generating heat for the endothermic reverse water gas shift reaction.

[0004] International Publication No. 2022079407(A1) describes a method for synthesizing hydrocarbons from synthesis gas. This method involves the use of a water electrolytic cell to produce hydrogen and oxygen as feedstock for a synthesis gas unit equipped with a reverse water-gas shift reactor. For each molecule of oxygen produced by electrolysis, two hydrogen molecules are also produced. A typical reverse water-gas shift reaction uses an excess of hydrogen compared to oxygen on a molar basis. The nature of the reverse water-gas shift reactor means that the oxygen feedstock experiences a greater pressure drop compared to the hydrogen feedstock when it enters the reactor. As a result, the oxygen feedstock needs to be supplied at a higher pressure than the hydrogen feedstock, typically at about 5 bara. This may be achieved by producing hydrogen and oxygen in the electrolytic cell at a lower desired hydrogen pressure, and then increasing the oxygen pressure to a higher desired oxygen pressure using an oxygen compressor, after which the oxygen is fed into the reverse water-gas shift reactor. However, the use of an oxygen compressor increases the CAPEX and OPEX of this method and raises safety concerns. Alternatively, hydrogen and oxygen may be produced in the electrolytic cell at a higher desired oxygen pressure, and the hydrogen may be sent to a reverse water-gas shift reactor after its pressure is reduced to a lower desired hydrogen pressure. However, the need to reduce the pressure of a large hydrogen flow rate reduces the efficiency of this method.

[0005] The present invention aims to address at least some of the problems related to the prior art, or to provide at least a commercially acceptable alternative solution. [Overview of the Initiative]

[0006] One aspect of the present disclosure is a method for generating a hydrogen stream and an oxygen stream and sending the hydrogen stream and the oxygen stream to a reverse water-gas shift reactor, wherein the method is The water flow Hydrogen flow at the first pressure, and To provide to an electrolytic system configured to form an oxygen flow at a second pressure, This includes supplying hydrogen, carbon dioxide, and oxygen streams to a reverse water-gas shift reactor. This relates to a method by which the first pressure is lower than the second pressure. [Brief explanation of the drawing]

[0007] [Figure 1] This is a diagram of a first embodiment of the method according to the present invention. [Figure 2] These are diagrams of second and third embodiments of the method according to the present invention. [Modes for carrying out the invention]

[0008] This disclosure relates to a method for generating hydrogen and oxygen streams and supplying hydrogen and oxygen streams to a reverse water-gas shift reactor, wherein this method is The water flow Hydrogen flow at the first pressure, and To provide to an electrolytic system configured to form an oxygen flow at a second pressure, The present invention relates to a method comprising supplying hydrogen, carbon dioxide, and oxygen streams to a reverse water-gas shift reactor, wherein the first pressure is lower than the second pressure.

[0009] The present invention may be carried out using an electrolytic system comprising a single electrolytic unit having a single type of electrolytic cell that provides a hydrogen flow at a first pressure and an oxygen flow at a second pressure. The single type of electrolytic cell may comprise a plurality of electrolytic subunits, each functioning similarly to perform electrolysis. Preferably, the present invention is carried out using an electrolytic system comprising a first electrolytic unit and a second electrolytic unit, each electrolytic unit comprising one or more electrolytic cells. Therefore, the present invention is To provide a first water flow and a second water flow, The first water flow is sent to the first electrolysis unit to form a first hydrogen flow and a first oxygen flow at a first pressure, The second water flow is sent to the second electrolysis unit to form a second hydrogen flow and a second oxygen flow at a second pressure, The first hydrogen stream and the second hydrogen stream are mixed, To form a mixed hydrogen flow, The method includes supplying a mixed hydrogen stream, a carbon dioxide stream, and a second oxygen stream to a reverse water-gas shift reactor.

[0010] Each aspect or embodiment defined herein may be combined with any other aspect or embodiment unless expressly indicated otherwise. Specifically, any feature indicated as preferred or advantageous may be combined with any other feature indicated as preferred or advantageous.

[0011] Advantageously, the method of the present invention avoids the need to compress the oxygen stream before sending it to the reverse water-gas shift reactor. This can improve the efficiency and safety of the method. In addition, there is no need to reduce the pressure of the hydrogen stream before sending it to the reverse water-gas shift reactor. As a result, the efficiency of the method can be increased.

[0012] Reverse water-gas shift reactors are known in the art. Under a reverse water-gas shift reaction, carbon dioxide and hydrogen are converted as follows:

[0013] [ka]

[0014] International Publication No. 2022079408(A1) discloses a typical reverse water-gas shift reactor. A reverse water-gas shift reactor typically converts some carbon dioxide and some hydrogen into carbon monoxide and water. As is understood, not all hydrogen is converted. This is because the resulting synthesis gas needs to contain hydrogen, for example, to later undergo the Fischer-Tropsch reaction. A typical reverse water-gas shift reactor may include a long-necked swage-connected vessel lined with refractory material. The feed gas typically enters the combustion region via a distributor to ensure a uniform flow and therefore uniform mixing. At the top of the vessel in the combustion region, oxygen is added to the hydrogen-concentrated environment via a burner nozzle. The long-necked design and the use of a high-momentum oxidizer jet burner provide a mixed and burned uniform feed gas to the catalyst bed. This ensures excellent reaction performance and physical stability of the catalyst. High mass flow and momentum transfer generate a relatively short, clear flame front, which minimizes back radiation at the burner tip, thereby preventing overheating of the burner tip. The lower part of the reactor contains a fixed catalyst bed where an endothermic reverse water-gas shift reaction takes place. This is situated above a refractory dome, often called a "refractory arch." The refractory arch has slots to allow the outlet gas to pass through, and a catalyst underbed of alumina balls exists to prevent catalyst loss through the refractory arch slots. An internal refractory lining is used to contain the high temperatures inside the reactor and is installed within a support shell. The shell is placed within a boiler feedwater jacket, which helps to remove heat loss by maintaining the shell temperature at around 100°C through water evaporation. Maintaining the shell temperature at 100°C minimizes thermal expansion and keeps the refractory material in a compressed state.

[0015] This method includes supplying a water flow to an electrolytic cell system. The water flow may be supplied in the form of liquid water or vapor.

[0016] In some arrangements, the electrolysis system consists of a single electrolysis unit with a single type of electrolytic cell. In such an arrangement, the single electrolysis unit may include an electrolytic cell having an anode that generates an oxygen stream at a higher pressure than a cathode that generates a hydrogen stream. However, this arrangement can generate excess pressurized oxygen that needs to be safely depressurized before being sent for use in other processes. In addition, the configuration of a single electrolytic cell can result in more or larger equipment being evaluated for higher oxygen pressures, resulting in higher manufacturing costs. Therefore, the electrolysis system preferably comprises a first electrolysis unit and a second electrolysis unit, each electrolysis unit comprising one or more electrolytic cells, and the method providing a first water stream and a second water stream; sending the first water stream to the first electrolysis unit to form a first hydrogen stream and a first oxygen stream at a first pressure; sending the second water stream to the second electrolysis unit to form a second hydrogen stream and a second oxygen stream at a second pressure; mixing the first hydrogen stream and the second hydrogen stream to form a mixed hydrogen stream; sending the mixed hydrogen stream, a carbon dioxide stream, and the second oxygen stream to a reverse water gas shift reactor.

[0017] This method includes providing one or more, preferably first and second, electrolysis units. Electrolysis units are known in the art. An electrolysis unit typically comprises a single type of electrolytic cell and associated auxiliary equipment. Suitable electrolysis units include, for example, alkaline electrolytic cells, polymer electrolyte membrane electrolytic cells (including proton exchange membrane electrolytic cells and anion exchange membrane electrolytic cells (also known as alkaline exchange membrane electrolytic cells)), and solid oxide electrolytic cell stacks, where the membrane can be either proton-conductive or oxygen-ion-conductive.

[0018] When there is a single electrolysis unit, hydrogen and oxygen can be produced at the pressure required for the reverse water gas shift reactor using a single polymer electrolyte membrane electrolyzer, such as a proton exchange membrane electrolyzer or an anion exchange membrane electrolyzer, operating in a differential pressure mode where the anode operates at a higher pressure than the cathode.

[0019] When there are a first electrolysis unit and a second electrolysis unit, the first electrolysis unit and the second electrolysis unit may be of the same type of electrolysis unit. Alternatively, the first electrolysis unit and the second electrolysis unit may be of different types of electrolysis units. In such an arrangement, the pressures of the anode and cathode in the electrolyzer may be the same or different, but the electrolyzer operates to provide hydrogen and oxygen flows at a first pressure and a second pressure.

[0020] In the electrolysis unit, electricity is used to decompose water into hydrogen and oxygen, i.e., the following.

[0021]

Chemical formula

[0022] The electrolysis system preferably operates at a temperature from ambient temperature to 1000 °C depending on the type of electrolysis unit used. For example, a polymer electrolyte membrane electrolyzer is typically used at a temperature in the range of 20 to 100 °C, while a solid oxide electrolyzer cell electrolyzer can be used at 400 to 1000 °C, preferably 450 to 900 °C.

[0023] The method includes sending a water stream to the electrolysis system to form a first hydrogen stream at a first pressure and an oxygen stream at a second pressure. To avoid the need to pressurize hydrogen, the first pressure is preferably the pressure at which the hydrogen stream is sent to the reverse water gas shift reactor.

[0024] In an arrangement including a first electrolytic unit and a second electrolytic unit, there are two hydrogen streams to be mixed, and a first oxygen stream and a second oxygen stream at different pressures. The first oxygen stream is not sent to the reverse water-gas shift reactor. This is because the first oxygen stream needs to be compressed before being sent to the reverse water-gas shift reactor, and the oxygen requirement is already met by the second oxygen stream, which is provided at a higher second pressure. The first oxygen stream may be formed at the first pressure or at a pressure lower than the first pressure.

[0025] In an arrangement including a first electrolytic unit and a second electrolytic unit, the method includes sending a second water stream to the second electrolytic unit to form a second hydrogen stream at a first pressure or a pressure higher than the first pressure, and a second oxygen stream at the second pressure.

[0026] In an arrangement including a first electrolytic unit and a second electrolytic unit, the method includes mixing the first hydrogen stream and the second hydrogen stream to form a mixed hydrogen stream. If the first pressure is the pressure required for hydrogen inflow into the reverse water-gas shift reactor, the second hydrogen stream may be reduced to the first pressure before being mixed with the first hydrogen stream. This ensures that the pressure of the mixed hydrogen stream is the pressure desirable for hydrogen inflow into the reverse water-gas shift reactor. The second oxygen stream is supplied to the reverse water-gas shift reactor. The first oxygen stream may be released into the atmosphere, used outside the process for combustion, or used as an oxidizer in a separate chemical process requiring oxygen at a lower pressure.

[0027] Alternatively, if a single electrolytic unit, including a single electrolytic cell type, is used, the cathode in the electrolytic cell generates all the hydrogen at the first pressure required for the reverse water-gas shift reactor, and the anode generates oxygen at the second pressure required for the reverse water-gas shift reactor. Any excess oxygen not supplied to the reverse water-gas shift reactor may be used outside the process for combustion, used as an oxidizer in a separate chemical process requiring oxygen, or supplied outside the battery limit at a reduced pressure.

[0028] The hydrogen stream or mixed hydrogen stream supplied to the reverse water-gas shift reactor is preferably subjected to purification in a hydrogen purification unit upstream of the reverse water-gas shift reactor.

[0029] The oxygen stream supplied to the reverse water-gas shift reactor is preferably purified in an oxygen purification unit upstream of the reverse water-gas shift reactor.

[0030] The purification step is performed in an electrolytic system or multiple electrolytic units downstream of one or more electrolytic cells to remove water / vapor and oxygen from hydrogen vapor, and to remove water / vapor and hydrogen from the oxygen stream, thus avoiding the transmission of explosive gas mixtures downstream.

[0031] Alternatively, or in addition, the contaminants may be removed from the hydrogen and / or oxygen streams in a purification unit located downstream of the electrolytic system or electrolytic unit and upstream of the reverse water-gas shift reactor. The carbon dioxide stream supplied to the reverse water-gas shift reactor may also be used for one or more purification steps.

[0032] This method involves supplying hydrogen and oxygen streams, as well as a carbon dioxide stream, from an electrolytic system to a reverse water-gas shift reactor. The hydrogen stream from the electrolytic system is at a pressure suitable for entering the reverse water-gas shift reactor.

[0033] The carbon dioxide stream may be mixed with the hydrogen stream from the electrolysis system, or it may be supplied separately to the reverse water-gas shift reactor.

[0034] The first hydrogen pressure flowing from the electrolysis system to the reverse water-gas shift reactor is lower than the second oxygen pressure flowing from the electrolysis system to the reverse water-gas shift reactor, for example, by at least 1 bar.

[0035] In a preferred embodiment, the reverse water-gas shift reactor is a catalytic reverse water-gas shift reactor. The use of a catalyst can increase the rate and / or yield and / or selectivity of the reverse water-gas shift reaction. In an alternative preferred embodiment, the reverse water-gas shift reactor is a non-catalytic reverse water-gas shift reactor.

[0036] Preferably, the reverse water-gas shift reactor is equipped with a reverse water-gas shift catalyst bed downstream of the burner, and the hydrogen stream is delivered to a reverse water-gas shift reactor adjacent to the burner and upstream of the reverse water-gas shift catalyst bed, while the oxygen stream is delivered to the burner. This can be a particularly effective configuration for the reverse water-gas shift reactor. In addition, in such a configuration, the pressure drop experienced by the oxygen stream may be significantly greater than the pressure drop experienced by the hydrogen stream.

[0037] In an arrangement including a first electrolytic unit and a second electrolytic unit, the amount of hydrogen in the first hydrogen stream sent to the reverse water-gas shift reactor is preferably 1.1 to 12 times the amount of hydrogen in the second hydrogen stream sent to the reverse water-gas shift reactor, based on volume or molar concentration. In embodiments in which hydrogen from the second electrolytic cell is produced at a pressure higher than the first pressure, this reduces the amount of hydrogen that needs to be depressurized, thereby increasing the efficiency of the method compared to a single electrolytic cell system having a single electrolytic cell that operates to provide hydrogen and oxygen streams at the second pressure.

[0038] The pressure of the hydrogen supplied from the electrolytic system to the reverse water-gas shift reactor, i.e., the first pressure, is lower than the pressure of the oxygen flowing into the reverse water-gas shift reactor, i.e., the second pressure. The first pressure is preferably 1 to 20 bar, more preferably 2 to 8 bar, lower than the second pressure. Such a pressure difference is characteristic of the difference in depressurization experienced by the hydrogen and oxygen streams, respectively, upon inflow into the reverse water-gas shift reactor.

[0039] Preferably, the first pressure is 10 to 55 bara and / or the second pressure is 11 to 60 bara. Such pressures are desirable for introducing the hydrogen stream and oxygen stream into the reverse water-gas shift reactor, respectively.

[0040] In an arrangement including a first electrolytic unit and a second electrolytic unit, if the pressure of the second hydrogen stream is greater than the first pressure, the method preferably further includes reducing the pressure of the second hydrogen stream to the first pressure to form a reduced-pressure second hydrogen stream, introducing the reduced-pressure second hydrogen stream into the first hydrogen stream to form a mixed hydrogen stream, and then sending the mixed hydrogen stream to a reverse water-gas shift reactor. This ensures that the mixed hydrogen stream is at a pressure desirable for inflow into the reverse water-gas shift reactor.

[0041] The electrolytic system may include an alkaline electrolytic cell, a polymer electrolyte membrane electrolytic cell, or a solid oxide electrolytic cell electrolytic cell. In an arrangement including a first electrolytic unit and a second electrolytic unit, the first electrolytic unit and / or the second electrolytic unit preferably include an alkaline electrolytic cell, a polymer electrolyte membrane electrolytic cell, or a solid oxide electrolytic cell electrolytic cell, more preferably an alkaline electrolytic cell or a polymer electrolyte membrane electrolytic cell. Such electrolytic cells are known in the art. Such electrolytic cells are particularly suitable for forming hydrogen and oxygen streams at pressures suitable for entering a reverse water-gas shift reactor.

[0042] In a preferred embodiment, both the first and second electrolytic cells are alkaline electrolytic cells, the first electrolytic cell produces hydrogen and oxygen at a first pressure, and the second electrolytic cell produces oxygen and hydrogen at a second pressure.

[0043] In alternative embodiments, the first and second electrolytic cells may be any combination of alkaline electrolytic cells, SOEC electrolytic cells, and polymer electrolyte membrane electrolytic cells operating in equilibrium pressure mode or differential pressure mode. In this embodiment, the first electrolytic cell will produce hydrogen at a first pressure, and the second electrolytic cell will produce oxygen at a second pressure. In one configuration, the first electrolytic unit comprises a solid oxide electrolytic cell, and the first hydrogen stream is pressurized before being sent to a reverse water-gas shift reactor. The second electrolytic unit comprises a polymer electrolyte membrane electrolytic cell or an alkaline electrolytic cell that operates in equilibrium pressure mode or differential pressure mode.

[0044] When a solid oxide electrolytic cell is used, the generated hydrogen and oxygen gas streams may exceed 450°C and, therefore, can be usefully supplied directly to the reverse water-gas shift reactor. If desired, the hydrogen and / or oxygen streams may be subjected to one or more steps within or downstream of the electrolytic system or electrolytic unit and upstream of the reverse water-gas shift reactor to cool to below this temperature. Cooling may be performed by heating one or more process streams, for example, by generating steam.

[0045] The electrolytic system or electrolytic unit is preferably powered by renewable energy. This can make the method more environmentally friendly.

[0046] In a further embodiment, the present invention relates to a method for producing a hydrocarbon product, wherein the method is The process involves generating a hydrogen stream and an oxygen stream, sending the hydrogen stream and the oxygen stream to a reverse water-gas shift reactor using the method described herein, and sending the hydrogen stream and the oxygen stream to the reverse water-gas shift reactor together with a carbon dioxide stream to form a synthesis gas in the reverse water-gas shift reactor in which carbon monoxide is concentrated. The synthesis gas, enriched with carbon monoxide, is sent to the Fischer-Tropsch unit to form hydrocarbon products, tail gas, and aqueous flow. The present invention provides a method that includes recovering hydrocarbon products.

[0047] The advantages and preferred features of the first embodiment are the same in this embodiment.

[0048] The term "hydrocarbon product" has its usual meaning in the art. As used herein, this term may encompass species formed from carbon and hydrogen, including those that are liquid at room temperature and room pressure. Hydrocarbon products typically include alkanes and typically contain 5 to 100 or more carbon atoms per molecule. The present invention is particularly suited to processes for the synthesis of liquid hydrocarbon fuels such as gasoline, diesel, and kerosene.

[0049] In this method, the hydrogen, oxygen, and carbon dioxide streams are all sent to a reverse water-gas shift reactor. The carbon dioxide stream may be any carbon dioxide stream. The carbon dioxide may be recovered from combustion gases, or it may be contained in a process stream such as a synthesis gas stream or biogas stream, or it may be separated from a process stream. The carbon dioxide may also be recovered from the air by direct air capture, or it may be recovered from seawater. The carbon dioxide stream may contain small amounts of other species, such as carbon monoxide, hydrogen, and water.

[0050] This method involves feeding a carbon monoxide-enriched synthesis gas into a Fischer-Tropsch unit to form hydrocarbon products, tail gas, and aqueous streams. Fischer-Tropsch reactors are known in the art. The temperature of the Fischer-Tropsch reactor is preferably 150°C to 300°C. Lower temperatures may result in undesirably low levels of hydrocarbon products. Higher temperatures may increase the energy cost of this method without significantly increasing the level of hydrocarbon products and the risk of thermal damage to the catalyst. The Fischer-Tropsch reactor preferably contains a catalyst comprising cobalt, iron, and / or ruthenium. Such catalysts are particularly effective in catalyzing the Fischer-Tropsch reaction and / or allow the reaction to proceed favorably at lower temperatures and / or in high yields. The molar ratio of hydrogen to carbon monoxide in the synthesis gas is preferably 1.8 to 2.2, as this is close to the stoichiometric ratio of approximately 2 for the Fischer-Tropsch reaction.

[0051] The tail gas may contain C1-C4 hydrocarbons, water, and one or more unreacted species such as hydrogen, carbon monoxide, and carbon dioxide.

[0052] The Fischer-Tropsch unit may include a downstream upgrade unit in which hydrocarbon products from the Fischer-Tropsch reactor are converted into useful liquid hydrocarbon products such as kerosene, diesel, and naphtha, along with by-products of liquid petroleum gas (LPG) and non-condensable off-gas, typically by hydrogenation using hydrogen gas.

[0053] The aqueous stream generated in the Fischer-Tropsch unit can be purified and then recycled into the first and / or second aqueous streams. Alternatively, or additionally, process condensates recovered from synthesis gas downstream of the reverse water-gas shift reactor can be purified and then recycled into the electrolytic system. This can reduce the amount of water required by the method. The aqueous stream is preferably purified at least partially before being sent to the electrolytic system. For example, hydrocarbons, ammonia, and dissolved gases can be removed from the aqueous stream. Impurities such as hydrocarbons can clog the electrolytic unit and / or contaminate the catalyst contained in the cathode and / or anode of the electrolytic unit. [Examples]

[0054] Figure 1 shows a diagram of a first embodiment of the method according to the present invention. A single water stream 10 is sent to an electrolytic system consisting of a single electrolytic unit with a single electrolytic cell type 12, forming a hydrogen stream 13 at the cathode at a pressure of 25 bar and a flow rate of 300 kmol / h, and also forming an oxygen stream 14 at the anode at a pressure of 30 bar and a flow rate of 150 kmol / h. The oxygen stream 14 is divided into a stream 15 with a flow rate of 120 kmol / h and a stream 16 with a flow rate of 30 kmol / h. This single electrolytic cell unit comprises a polymer membrane electrolyte electrolytic cell operating in differential mode, with an anode operating at a higher pressure than the cathode. The hydrogen stream 13, oxygen stream 16, and carbon dioxide stream 17 are sent to a reverse water-gas shift reactor 18. The oxygen stream 15 may be depressurized (upstream or downstream of the equilibrium of the plant unit) and sent outside the battery limit. In the reverse water-gas shift reactor 18, some of the hydrogen 13 burns together with oxygen 16, and the high-temperature gas mixture containing carbon dioxide 17 flows through the bed of the reverse water-gas shift catalyst, forming a synthesis gas containing carbon monoxide and hydrogen, which is recovered from the reactor 18 via line 19. The synthesis gas from line 19 is converted into hydrocarbon products in a Fischer-Tropsch unit (not shown).

[0055] Figure 2 shows second and third embodiments of the method according to the present invention, using a first electrolytic unit and a second electrolytic unit. In the second embodiment, the water stream 20 is divided and supplied to the first electrolytic unit 21 and the second electrolytic unit 22. The first electrolytic unit 21 forms a hydrogen stream 23 at a pressure of 25 bar and a flow rate of 240 kmol / h and an oxygen stream 24 at a pressure of 25 bar and a flow rate of 120 kmol / h. The second electrolytic unit 22 forms another hydrogen stream 25 at a pressure of 30 bar and a flow rate of 60 kmol / h and another oxygen stream 26 at a pressure of 30 bar and a flow rate of 30 kmol / h. The electrolytic cell units 21 and 22 each include one or more alkaline electrolytic cells. The hydrogen stream 25 from the electrolytic unit 22 is reduced to 25 bar (upstream or downstream of the equilibrium of the plant unit), mixed with the hydrogen stream 23 from the electrolytic unit 21 to form a mixed hydrogen stream 27, which is sent to the reverse water-gas shift reactor 28. The oxygen stream 24 from the electrolytic unit 21 may be depressurized (upstream or downstream of the plant unit's equilibrium) and sent outside the battery limit. The oxygen stream 26 from the electrolytic unit 22 is sent to the reverse water-gas shift reactor 28. The carbon dioxide stream 29 is also supplied to the reverse water-gas shift reactor. In the reverse water-gas shift reactor 28, a portion of the mixed hydrogen stream 27 burns together with the oxygen 26, and the high-temperature gas mixture containing carbon dioxide 29 flows through the bed of the reverse water-gas shift catalyst, forming a synthesis gas containing carbon monoxide and hydrogen, which is recovered from the reactor 28 via line 30. The synthesis gas from line 30 is converted into hydrocarbon products in a Fischer-Tropsch unit (not shown).

[0056] The third embodiment differs from the second embodiment in that the electrolytic unit 21 comprises an alkaline electrolytic cell, a polymer electrolyte membrane operating in equilibrium pressure mode or differential pressure mode, or a solid oxide electrolytic cell. When a solid oxide electrolytic cell is used, the hydrogen stream 23 may require an additional compression step before being mixed with the hydrogen stream 25. When a polymer electrolyte membrane electrolytic cell is used in differential mode with a cathode operating at a higher pressure than the anode, the oxygen stream 24 may not require depressurization. In addition, the electrolytic unit 22 may comprise an alkaline electrolytic cell or a polymer electrolyte membrane operating in equilibrium pressure mode or differential pressure mode, in which case the anode operates at a higher pressure than the cathode. When a polymer electrolyte membrane electrolytic cell is used in differential mode with an anode operating at a higher pressure than the cathode, the hydrogen stream 25 may not require depressurization before being mixed with the hydrogen stream 23.

[0057] The detailed description above is provided for illustrative and illustrative purposes only and is not intended to limit the scope of the appended claims. Many modifications of the currently preferred embodiments shown herein will be obvious to those skilled in the art and remain within the scope of the appended claims and their equivalents.

Claims

1. A method for generating a hydrogen stream and an oxygen stream, and sending the hydrogen stream and the oxygen stream to a reverse water-gas shift reactor, wherein the method is The water flow Hydrogen flow at the first pressure, and To provide an electrolytic system configured to form an oxygen flow at a second pressure, This includes sending the hydrogen stream, carbon dioxide stream, and oxygen stream to the reverse water-gas shift reactor, A method wherein the first pressure is lower than the second pressure.

2. The method according to claim 1, wherein the electrolysis system comprises a single electrolysis unit having a single type of electrolytic cell having an anode that generates the oxygen flow at a pressure higher than the cathode that generates the hydrogen flow.

3. The electrolysis system comprises a first electrolysis unit and a second electrolysis unit, and each electrolysis unit comprises one or more electrolytic cells. To provide a first water flow and a second water flow, The first water flow is sent to the first electrolysis unit to form a first hydrogen flow and a first oxygen flow at the first pressure, The second water flow is sent to the second electrolysis unit to form a second hydrogen flow and a second oxygen flow at the second pressure, The first hydrogen stream and the second hydrogen stream are mixed, To form a mixed hydrogen flow, The method according to claim 1, comprising sending the mixed hydrogen stream, the carbon dioxide stream, and the second oxygen stream to the reverse water-gas shift reactor.

4. The method according to any one of claims 1 to 3, wherein the reverse water-gas shift reactor is a catalytic or non-catalytic reverse water-gas shift reactor.

5. The aforementioned reverse water-gas shift reactor is equipped with a reverse water-gas shift catalyst bed downstream of the burner. The method according to any one of claims 1 to 4, wherein the hydrogen stream is delivered to the reverse water-gas shift reactor which is adjacent to the burner and upstream of the reverse water-gas shift catalyst bed, and the oxygen stream is delivered to the burner.

6. The method according to any one of claims 3 to 5, wherein the amount of hydrogen contained in the first hydrogen stream sent to the reverse water-gas shift reactor is 1.1 to 12 times the amount of hydrogen contained in the second hydrogen stream sent to the reverse water-gas shift reactor.

7. The method according to any one of claims 1 to 6, wherein the first pressure is 1 to 20 bar, preferably 2 to 8 bar, lower than the second pressure.

8. The method according to any one of claims 1 to 7, wherein the first pressure is 10 to 55 bara and / or the second pressure is 11 to 60 bara.

9. The pressure of the second hydrogen stream is higher than the pressure of the first stream. The second hydrogen stream is reduced in pressure to the first pressure to form a reduced-pressure second hydrogen stream, The method according to any one of claims 3 to 8, further comprising introducing the depressurized second hydrogen stream into the first hydrogen stream to form the mixed hydrogen stream, and then sending the mixed hydrogen stream to the reverse water-gas shift reactor.

10. The method according to any one of claims 1 to 9, wherein a hydrogen stream is supplied to a hydrogen purification unit upstream of the reverse water-gas shift reactor.

11. The method according to any one of claims 1 to 10, wherein an oxygen stream is supplied to an oxygen purification unit upstream of the reverse water-gas shift reactor.

12. The method according to any one of claims 1 to 11, wherein the electrolytic system comprises an alkaline electrolytic cell, a polymer electrolyte membrane electrolytic cell, or a solid oxide electrolytic cell electrolytic cell, preferably an alkaline electrolytic cell or a polymer electrolyte membrane electrolytic cell.

13. The method according to any one of claims 3 to 12, wherein the first electrolytic unit and the second electrolytic unit each include an alkaline electrolytic cell.

14. The method according to any one of claims 3 to 12, wherein the first electrolytic unit and / or the second electrolytic unit comprises an alkaline electrolytic cell or a polymer electrolyte membrane electrolytic cell operating in equilibrium pressure mode or differential pressure mode.

15. The method according to any one of claims 1 to 14, wherein the oxygen stream is not compressed before being sent to the reverse water-gas shift reactor.

16. The first electrolytic unit comprises a solid oxide electrolytic cell, and the first hydrogen stream is pressurized before being sent to the reverse water-gas shift reactor. The method according to any one of claims 3 to 12, wherein the second electrolytic unit comprises a polymer electrolyte membrane electrolytic cell or an alkaline electrolytic cell operating in equilibrium pressure mode or differential pressure mode.

17. The method according to any one of claims 1 to 16, wherein the electrolysis system is powered by renewable energy.

18. The method according to any one of claims 1 to 17, wherein process aggregates recovered from synthesis gas downstream of the reverse water-gas shift reactor are purified and recycled to the electrolysis system.

19. A method for producing hydrocarbon products, wherein the method is Generating a hydrogen stream and an oxygen stream, and sending the hydrogen stream and the oxygen stream to a reverse water-gas shift reactor using the method described in any one of claims 1 to 18, thereby forming a synthesis gas in which carbon monoxide is concentrated in the reverse water-gas shift reactor. The synthesis gas, which is concentrated with carbon monoxide, is sent to a Fischer-Tropsch unit to form hydrocarbon products, tail gas, and aqueous flow. A method comprising recovering the hydrocarbon product.

20. The method according to claim 19, wherein the aqueous stream generated in the Fischer-Tropsch unit is purified and recycled to the electrolytic system.

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