Method for recovering hydrogen-enriched product and CO2 in a hydrogen generation unit

Abstract

A process for generating a hydrogen-enriched gas stream is described. A hydrocarbon-containing feed is processed in a hydrogen production process unit, and the formed synthesis gas is subjected to a water gas shift reaction. The shifted synthesis gas is sent to a process for recovering hydrogen and carbon dioxide. The hydrogen and carbon dioxide recovery process separates a purified hydrogen product stream and a purified carbon dioxide stream from the shifted synthesis stream, and recycles the synthesis gas to the reforming feed after recovery of CO2 and H2, thereby avoiding carbon slip from the process and reducing the overall carbon intensity.

Description

Technical Field

[0001] (Priority Claim) This application claims the priority of U.S. Patent Application No. 17 / 806,638, filed on June 13, 2022, which is hereby incorporated by reference in its entirety.

Background Art

[0002] Hydrogen is expected to have significant growth potential as it is a clean-burning fuel. However, hydrogen production has traditionally been a significant source of CO2 emissions, and government regulations and social pressure are increasingly taxing or penalizing CO2 emissions or encouraging CO2 capture. As a result, significant competition is expected to reduce the cost of hydrogen production while recovering the byproduct CO2 for subsequent geological sequestration to capture the growing market. CO2 can be recovered as a high-pressure gas supplied to pipelines, but in many cases, it is produced in liquefied form for easy transportation by truck or ship due to the lack of CO2 pipeline infrastructure in certain regions of the world today.

[0003] There is a growing interest in minimizing CO2 emissions from hydrogen production processes based on steam reforming, autothermal reforming, partial oxidation, or gasification of hydrocarbon or carbonaceous feedstocks. A method to achieve this objective is to add CO2 capture to the process, along with recycling of unconverted carbon-containing components (carbon monoxide and methane) within the process. Ideally, all of the unreacted carbon-containing components (carbon monoxide and methane) are recycled to the reactor for complete conversion to CO2 and hydrogen, resulting in zero carbon slip to the atmosphere. However, the presence of inert components such as nitrogen and argon in the hydrocarbon or carbonaceous feedstock, or oxygen feedstock to such a process, creates problems with this approach. These inert components accumulate within the recycle loop and typically must be purged from the system as a fuel gas stream. This purge stream also contains carbon-containing components (carbon monoxide and methane), resulting in carbon emissions to the atmosphere. Therefore, there is a need for a method to efficiently and selectively purge inert components from the process without increasing carbon emissions.

[0004] Most existing hydrogen production processes utilize pressure swing adsorption (PSA) to recover high-purity product hydrogen from syngas. The low-pressure tail gas stream from the PSA unit is typically burned to generate heat for the process. If the stream is not sent to the combustor, a purge is required to prevent accumulation of inert gases in the process.

[0005] U.S. Patent No. 8,021,464 describes a process for producing a combination of hydrogen and CO2 from a hydrocarbon mixture that is converted to syngas. The syngas is separated in a PSA unit into a hydrogen-enriched stream and a PSA off-gas stream. The PSA off-gas is compressed and dried, followed by several consecutive steps of condensing and separating a CO2-rich condensate while the temperature is reduced in each step, and the temperature ranges from ambient temperature to -56°C. However, this process results in a purge stream containing a significant amount of CO2 that must be removed from the process. A permeate module can be used to improve separation, but at the expense of increased power requirements.

[0006] U.S. Patent No. 8,241,400 describes a process for recovering hydrogen and CO2 from a hydrocarbon mixture using a system that includes a reformer unit, an optional water gas shift reactor, a PSA unit, and an ultra-low temperature purification unit or a catalytic oxidizer. The PSA unit produces three streams: a high-pressure hydrogen stream, a low-pressure CO2 stream, and a CH4-rich stream that can be withdrawn during a CO2 co-purge step and recycled to the reformer unit. The purified CO2 from the CO2 purification unit in the process is used as a co-purge in the PSA unit. The adsorption step is carried out at a pressure of 250 psig to 700 psig. The pressure during the co-purge step is within the range of 300 psig to 800 psig, and the CO2 co-purge stream is preferably introduced at a pressure higher than the pressure during the adsorption step.

[0007] The use of a second high-pressure feed stream (CO2 co-purge stream) increases the cost and complexity of the process in U.S. Patent No. 8,241,400. The need to have a segmented adsorber (or two separate vessels) with an isolation valve between the two vessels and an intermediate side draw further increases the cost and complexity of the process.

[0008] U.S. Patent Application Publication No. 2021 / 175662 (A1) describes a hydrogen production process based on the reforming of hydrocarbon feedstocks, in which hydrogen and CO2 are recovered from the process. The remaining gas containing unreacted carbon-containing components is recycled within the process. As described above, the problem associated with this approach is carbon emissions caused by purging inert components (argon and / or nitrogen) from the recycle loop.

[0009] As the global demand for fuels such as aviation fuel increases, there is also a growing interest in using sources other than petroleum crude oil to produce fuels. One source is so-called bio-renewable feedstocks. These bio-renewable feedstocks include, but are not limited to, vegetable oils such as corn, jatropha, camelina, rapeseed, canola, soybean and algal oil, animal fats such as tallow and fish oil, and various waste streams such as yellow and brown greases and sewage sludge. A common feature of these feedstocks is that they are composed of mono-, di- and tri-glycerides, free fatty acids (FFA). Another class of compounds suitable for these processes is fatty acid alkyl esters (FAAE) such as fatty acid methyl ester (FAME) or fatty acid ethyl ester (FAEE). These types of compounds generally contain an aliphatic carbon chain having 8 to 24 carbon atoms. The aliphatic carbon chain in glycerides, FFA or FAAE can be saturated, or mono-, di- or poly-unsaturated. Most of the glycerides in bio-renewable feedstocks are triglycerides, but some of the glycerides in bio-renewable feedstocks can be monoglycerides or diglycerides. Monoglycerides and diglycerides can be processed together with triglycerides.

[0010] There are reports disclosing the production of hydrocarbons from bio-based oils. For example, U.S. Patent No. 4,300,009 discloses the use of crystalline aluminosilicate zeolites for converting vegetable oils such as corn oil into hydrocarbons such as gasoline and chemicals such as paraxylene. U.S. Patent No. 4,992,605 discloses the production of hydrocarbon products in the diesel boiling range by hydrotreating vegetable oils such as canola oil or sunflower oil. Finally, U.S. Patent Application Publication No. 2004 / 0230085(A1) discloses a process for treating hydrocarbon components of biological origin by hydrodeoxygenation followed by isomerization.

Summary of the Invention

[0011] Therefore, an improved hydrogen production process with minimal carbon intensity is needed.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Modes for Carrying Out the Invention

[0013] Various processes for hydrogen production have been developed. Some of these processes involve reforming a hydrocarbon-containing feed, subjecting the formed syngas to a water-gas shift reaction, and recovering hydrogen and carbon dioxide. The hydrogen recovery and carbon dioxide process involves recovering a purified hydrogen product stream from the shifted syngas stream. The hydrogen recovery process also results in the production of CO2.

[0014] It is desirable to minimize the carbon intensity of these processes. One low-carbon intensity scheme is shown in FIG. 1. In this configuration, the purge gas from the bioregenerable conversion process can be separated in a membrane separation unit into a permeate stream rich in hydrogen that can be used as fuel gas in the steam reforming process and a hydrogen-depleted carbon-rich residue stream that can be used as an auxiliary reforming feed. This process reduces the amount of natural gas feed required and fuel consumption in the steam reforming process, resulting in lower carbon emissions. The shifted syngas is separated into CO2 and H2 products in a two-stage PSA system. The second-stage hydrogen recovery is adjusted to provide a fuel gas rich in hydrogen sufficient to meet the load of the steam reforming furnace, thereby avoiding direct ignition of natural gas.

[0015] FIG. 1 shows one embodiment of a hydrogen production process 100 incorporating a three-product PSA system. Additional information regarding this process can be found in U.S. Patent Application No. 17 / 508,349, filed Oct. 22, 2021, U.S. Provisional Patent Application No. 63 / 220,848, filed Jul. 12, 2021, U.S. Provisional Patent Application No. 63 / 167,343, filed Mar. 29, 2021, and U.S. Provisional Patent Application No. 63 / 167,341, filed Mar. 29, 2021, each of which is hereby incorporated by reference in its entirety.

[0016] A natural gas feed 105 and water 110 are sent to the reaction section 112 of a steam reforming process unit 120, and an auxiliary fuel gas 114 and air 115 are sent to a furnace 118 within the steam reforming process unit 120. Other feed streams containing hydrocarbons can be used in place of natural gas.

[0017] Steam reforming and water gas shift reactions produce an effluent stream 125 containing hydrogen, CO2, water, and at least one of methane, carbon monoxide, and nitrogen. A flue gas stream 130 and a steam stream 135 also exit the steam reforming process unit 120.

[0018] The effluent stream 125 has a temperature of 30°C to 50°C (after heat recovery and cooling in the steam reforming process) and a pressure of 2,000 to 3,000 kPa. The effluent stream 125 is sent to a hydrogen PSA unit 140 where it is separated into a high-purity hydrogen stream 145 enriched in hydrogen and a hydrogen-depleted tail gas stream 150 containing at least a portion of a portion of hydrogen, CO2, water, and at least one of methane, carbon monoxide, and nitrogen.

[0019] The hydrogen-depleted tail gas stream 150 is sent to a compressor 155 where it is compressed from a pressure in the range of 110 kPa to 200 kPa to a pressure in the range of 3,000 kPa to 6,000 kPa.

[0020] The compressed tail gas stream 160 is sent to a CO2 recovery unit 165 where it is dried, the water stream 167 is removed, it is cooled to a temperature of -20°C to -50°C, and separated into a bottom stream 170 and a top stream 175. The bottom stream 170 containing liquid CO2 is recovered.

[0021] The top stream 175 is sent to a three-product PSA system 180 equipped with a three-product PSA unit 185 where it is separated into three streams. A high-pressure hydrogen stream 190 is recovered. All or part of the high-pressure hydrogen stream 190 can be sent to a bioregenerable conversion process and combined with a makeup hydrogen stream for the bioregenerable conversion process. The low-pressure CO2 stream 195 is recycled to the compressor 155.

[0022] An intermediate-pressure vent gas stream 200 containing at least a portion of at least one of methane, carbon monoxide, and nitrogen and a small amount of hydrogen (e.g., less than 20%, or 10% to 20%) is sent to the steam reforming process unit 120 as fuel.

[0023] The purge gas stream containing hydrogen 44 from the bioregenerable conversion process is sent to the membrane separation unit 205, where it is separated into a permeate stream 210 containing hydrogen and CO2 and a residue stream 215 containing at least one of methane, ethane, propane, C4+ hydrocarbons, and carbon monoxide. The permeate stream 210 is sent to the compressor 155 and then to the CO2 recovery system 165 and the three-product PSA system 180 to recover the hydrogen and CO2 in the permeate stream 210. In one embodiment, all or a portion of the residue stream 215 is mixed with the intermediate pressure vent gas stream 200 and sent to the furnace 118 of the steam reforming process unit 120. In another embodiment, all or a portion of the residue stream 215 can be mixed with the natural gas feed 105 and sent to the steam reforming process unit 120. If the hydrogen process unit is an autothermal reforming unit having an optional gas heating reformer, gasification unit, or partial oxidation unit, all or a portion of the residue stream 215 can be mixed with a feed stream containing hydrocarbons and partially oxidized in the autothermal reforming unit, gasification unit, or partial oxidation unit. In yet another embodiment, all or a portion of the residue stream 215 can be sent back to the bioregenerable hydrocarbon production process for hydrocarbon recovery. 4+ It can be returned to the bioregenerable hydrocarbon production process for hydrocarbon recovery.

[0024] The bypass line 202 sends the hydrogen-depleted tail gas stream 150 to the furnace in the steam reforming process unit for combustion. Thereby, the steam reforming process unit can continue to operate without recovering CO2 in the event of a problem with the compressor 155, the CO2 recovery unit 165, or the three-product PSA system 180.

[0025] One drawback to this approach is that all of the carbon slip from the steam reforming process (methane and CO) is burned in the furnace, resulting in some fossil fuel-based CO2 emissions. This leads to constraints on the steam reforming process design to minimize carbon slip (e.g., lower operating pressure, high steam:carbon ratio, two-stage water gas shift, etc.), resulting in sub-optimal steam reforming process conditions and higher costs. Therefore, there is a need to improve the process configuration to achieve lower carbon intensity with a more efficient steam reforming design.

[0026] This process solves this problem by recycling the syngas to the reforming feed after the recovery of CO2 and H2, thereby avoiding carbon slip and reducing the overall carbon intensity. As a result, previous constraints on the reforming process are removed. One feature of this design is the selective removal of inert components (nitrogen and / or argon) in the PSA hydrogen unit, thereby avoiding the accumulation of inert gas in the recycle loop.

[0027] One aspect of the present invention is a method for generating a hydrogen-enriched gas stream. In one embodiment, the method includes processing a feed stream containing a hydrocarbon (such as natural gas, liquefied petroleum gas, or naphtha) or a carbonaceous feedstock (such as coal, petroleum coke, or biomass) in a hydrogen production process unit to produce a syngas mixture containing hydrogen, carbon monoxide, methane, water, and an inert gas, performing a water gas shift process on the syngas mixture to form a shifted syngas containing carbon dioxide, performing a hydrogen pressure swing adsorption (PSA) separation process and a carbon dioxide separation process on the shifted syngas to form a high-pressure hydrogen production stream containing hydrogen, an inert gas-enriched offgas stream from the hydrogen separation process containing an inert gas and depleted of carbon-containing components, a carbon dioxide production stream containing carbon dioxide, and a carbon-enriched offgas stream containing carbon monoxide and methane, wherein the hydrogen PSA process includes forming a three-product PSA system including a three-product PSA unit or at least two PSA units, and recycling the carbon-enriched offgas stream to the hydrogen production process unit.

[0028] A feed stream containing a hydrocarbon or a carbonaceous feedstock is processed in a hydrogen production process unit. Suitable hydrogen production process units include, but are not limited to, a steam reforming unit having an optional gas heating reformer, an autothermal reforming unit having an optional gas heating reformer, or a gasification unit, or a partial oxidation (POX) unit, or a combination thereof.

[0029] The syngas mixture produced in the hydrogen production process contains hydrogen, carbon monoxide, methane, water, and an inert gas such as nitrogen and argon. The syngas mixture undergoes a water gas shift reaction to convert carbon monoxide to carbon dioxide and additional hydrogen.

[0030] The hydrogen concentration in the syngas mixture is generally in the range of 50 mol% to 80 mol%. For example, the hydrogen concentration in the shift syngas of a steam methane reforming plant is 60 mol% to 80 mol%, while the hydrogen concentration in the POX reactor is 50 mol% to 70 mol%.

[0031] The shift syngas is separated in a hydrogen PSA separation process and a carbon dioxide separation process.

[0032] The hydrogen PSA separation process and the carbon dioxide separation process form a high-pressure hydrogen product stream containing hydrogen, an inert gas-enriched offgas stream from the hydrogen separation process containing inert gas and depleted in carbon-containing components, a carbon dioxide product stream containing carbon dioxide, and a carbon-enriched offgas stream containing carbon monoxide and methane. The term "inert gas-enriched offgas stream" means that the stream has at least three times more (mol%) inert gas (e.g., nitrogen and argon), typically in the range of three to eight times more inert gas, than the incoming shift syngas (mol%). The term "carbon-enriched offgas stream" means that the stream has at least five times more (mol%), typically five to fifteen times more, carbon monoxide and methane than in the shift syngas (mol%).

[0033] The temperature of the feed gas mixture flowing into the hydrogen and CO2 recovery system is typically in the range of 20°C to 60°C, or 30°C to 50°C, or 40°C (or any combination of temperature ranges).

[0034] The high-pressure hydrogen product stream and the carbon dioxide product stream are recovered. The high-pressure hydrogen product stream typically contains more than 99.0 mol%, or more than 99.9 mol%, or more than 99.99 mol% hydrogen. The carbon dioxide product stream typically contains more than 95 mol%, or more than 99.0 mol%, or more than 99.9 mol% carbon dioxide.

[0035] The inert gas-enriched offgas stream is enriched in inert gases such as nitrogen and argon and depleted in carbon-containing components such as carbon dioxide, carbon monoxide, and methane. It also contains hydrogen and can be burned as fuel in a hydrogen production process or elsewhere in the plant.

[0036] The carbon-enriched offgas stream is recycled to the hydrogen production process unit and used as at least part of the feed for the hydrogen treatment unit.

[0037] The amount of the carbon-enriched offgas stream recycled to the hydrogen production process unit can constitute less than 80%, or less than 70%, or less than 60%, or less than 50%, or less than 40% of the total amount of the carbon-enriched offgas stream and the inert gas-enriched offgas stream.

[0038] The order of the separation processes is not important. The hydrogen PSA separation can be first and the carbon dioxide separation second, or the carbon dioxide separation can be first and the hydrogen PSA separation second.

[0039] When the shift synthesis gas is first introduced into the hydrogen PSA separation process, the shift synthesis gas is introduced into a three-product PSA system to form a high-pressure hydrogen production stream, an inert gas-enriched offgas stream, and a low-pressure hydrogen-depleted tail gas stream. Then, the low-pressure hydrogen-depleted tail gas stream is introduced into a carbon dioxide recovery system to form a carbon dioxide production stream and a carbon-enriched offgas stream.

[0040] When the shift synthesis gas is first introduced into the carbon dioxide recovery system, a carbon dioxide production stream and a carbon dioxide-depleted stream are formed. Then, the carbon dioxide-depleted stream is introduced into a three-product PSA system to form a high-pressure hydrogen stream, an inert-material-enriched offgas stream, and a carbon-enriched offgas stream.

[0041] The carbon dioxide recovery system can be any suitable recovery system known to those skilled in the art. Suitable carbon dioxide recovery systems include, but are not limited to, amine separation units, cryogenic separation units, carbon dioxide PSA units, or combinations thereof.

[0042] The hydrogen PSA separation process includes a three-product PSA system. The three-product PSA system includes a three-product PSA unit or at least two PSA units.

[0043] The three-product PSA unit includes PSA adsorption vessels. Generally, there are at least six vessels, and typically there are 8 - 14 vessels. The vessels include one or more adsorbent layers, generally 1 - 5, typically 2 - 3 adsorbent layers. The percentage of the adsorbent bed is typically 10% - 100%. Different layers of the adsorbent have different selectivities for the components in the feed stream, as known to those skilled in the art. For example, in hydrogen production processes and CO2 recovery, some layers contain adsorbents for the selective adsorption of CO2 over methane, carbon monoxide, nitrogen, argon, and hydrogen, including but not limited to layers of activated alumina, silica gel, and sodium Y zeolite. Other layers contain adsorbents for the selective adsorption of hydrogen over CO2, methane, carbon monoxide, nitrogen, and argon, including but not limited to layers of activated carbon, silica gel, and molecular sieve zeolites (e.g., 5A or sodium X zeolite). Those skilled in the art understand that other zeolites can be used and know how to select appropriate adsorbents.

[0044] One end of the vessel has a first opening, and the opposite end has a second opening. For convenience, these ends are referred to as the top and bottom of the vessel. The first opening at the bottom is selectively connected to a high-pressure feed gas inlet line and a low-pressure tail gas outlet line. The second opening at the top of the vessel is selectively connected to a high-pressure product outlet line, an intermediate-pressure vent gas outlet line, and a low-pressure purge gas inlet line.

[0045] The feed gas enters at high pressure through a first opening at the bottom of the vessel, and a high-pressure co-current adsorption and product removal step is performed. The product exits the vessel at high pressure through a second opening at the top of the vessel. There is at least one co-current depressurization step, followed by an intermediate-pressure co-current depressurization and vent gas removal step. A second stream is removed through an opening at the top of the vessel at a second pressure. There is a counter-current blowdown step and a counter-current purge step. The purge gas enters through an opening at the top of the vessel at low pressure. CO2 can be removed at low pressure through an opening at the bottom of the vessel either during or both during the counter-current blowdown step and the counter-current purge step. Following the counter-current purge and tail gas removal step, there is at least one counter-current repressurization step.

[0046] The three-product PSA unit is described in more detail, for example, in U.S. Patent Application No. 17 / 451,935, filed on October 22, 2021, which is hereby incorporated by reference in its entirety.

[0047] Alternatively, the three-product separation system can be at least two PSA units. In this case, at least two PSA units are in series. The shifted synthesis gas is introduced into the first PSA unit to form a carbon component-enriched tail gas stream enriched in carbon dioxide, carbon monoxide, and methane, and a hydrogen-enriched intermediate stream enriched in inert components (nitrogen and / or argon). The hydrogen-enriched intermediate stream is introduced into the second PSA unit to form a high-pressure hydrogen product stream and an inert-substance-enriched off-gas stream. The carbon component-enriched tail gas stream is then introduced into a carbon dioxide recovery system.

[0048] The three-product PSA system including at least two PSA units is further described, for example, in U.S. Patent Application No. 17 / 508,349, filed on October 22, 2021, which is hereby incorporated by reference in its entirety.

[0049] Hydrogen PSA separation is first. When the three-product PSA system includes a three-product PSA unit, the shift synthesis gas is introduced into the three-product PSA unit to form a high-pressure hydrogen product stream, an inert gas-enriched off-gas stream, and a hydrogen-depleted tail gas stream. Then, the hydrogen-depleted tail gas stream is introduced into a carbon dioxide recovery system and separated into a carbon dioxide product stream and a carbon-enriched off-gas stream.

[0050] Hydrogen PSA separation is first. When the three-product PSA system includes at least two two-product PSA units, the shift synthesis gas is introduced into the first PSA unit to form a carbon component-enriched tail gas stream enriched in carbon dioxide, carbon monoxide, and methane, and a hydrogen-enriched intermediate stream enriched in inert components (nitrogen and / or argon). The hydrogen-enriched intermediate stream is introduced into the second PSA unit to form a high-pressure hydrogen product stream and an inert substance-enriched off-gas stream. Then, the carbon component-enriched tail gas stream is introduced into a carbon dioxide recovery system.

[0051] Typically, 70% to 90% of the hydrogen in the synthesis gas mixture to the hydrogen PSA system is recovered in the high-pressure product stream. In some cases, the high-pressure hydrogen stream is substantially free of CO2, methane, carbon monoxide, nitrogen, and argon. Typically, it contains less than 1%, or less than 0.1%, or less than 0.01% CO2 relative to the feed gas mixture. Typically, it contains less than 10%, or less than 5%, or less than 2%, or less than 1%, or less than 0.1% methane, carbon monoxide, nitrogen, and argon relative to the feed gas mixture. The high-pressure product stream is typically removed at a high pressure in the range of 1,000 to 6,000 kPa, or 2,000 kPa to 5,000 kPa, or 2,500 kPa to 4,500 kPa.

[0052] The hydrogen-depleted tail gas stream is typically removed at a low pressure in the range of 50 kPa to 250 kPa, or 100 kPa to 200 kPa.

[0053] The hydrogen-depleted tail gas stream typically contains 95% to 100% CO2 in the feed gas mixture. It typically contains 10% hydrogen (e.g., 5% to 15%) relative to the feed gas mixture, and 40% methane, carbon monoxide, nitrogen, and argon (e.g., 20% to 60%) relative to the feed.

[0054] The inert gas-enriched stream from the three-product PSA unit is removed at an intermediate pressure between the high pressure and the low pressure, which is much closer to the low pressure than to the high pressure, typically within 400 kPa, or 300 kPa, or 200 kPa of the low pressure. Typically, the intermediate pressure product stream is removed at a pressure within the range of 150 kPa to 450 kPa, or 250 kPa to 350 kPa. There is some overlap between the intermediate pressure range and the low pressure range, but in certain cases, it is understood that the low pressure is lower than the intermediate pressure.

[0055] In some embodiments, the carbon-enriched offgas stream is introduced into a membrane separation unit to form a permeate stream enriched in hydrogen (e.g., more than 80%, or more than 90%, or more than 95% of the hydrogen in the carbon-enriched offgas stream to the membrane separation unit is recovered in the permeate stream), and a residue stream enriched in carbon monoxide and methane (e.g., more than 70% of the carbon monoxide and more than 70% of the methane in the carbon-enriched offgas stream to the membrane separation unit are recovered in the residue stream, or more than 80%, or more than 90%). In this configuration, recycling the carbon-enriched offgas stream to the hydrogen production process unit includes recycling the residue stream to the hydrogen production process unit. The permeate stream can optionally be combined with the inert gas-enriched stream.

[0056] If the carbon dioxide separation process is first, the shift syngas is introduced into a carbon dioxide recovery system to form a carbon dioxide product stream and a carbon dioxide-depleted stream. The carbon dioxide-depleted stream is introduced into a three-product PSA system to form a high-pressure hydrogen stream, an inert gas-enriched offgas stream, and a carbon-enriched offgas stream.

[0057] When the three-product PSA system includes a three-product PSA unit, the carbon dioxide depleted stream is introduced into the three-product PSA unit to form a high-pressure hydrogen product stream, an inert gas enriched off-gas stream, and a carbon enriched off-gas stream.

[0058] When the three-product PSA system includes at least two PSA units, the carbon dioxide depleted stream is introduced into the first PSA unit to form a carbon enriched off-gas stream and a hydrogen enriched intermediate stream in which the inert components (nitrogen and / or argon) are also enriched. The hydrogen enriched intermediate stream is introduced into the second PSA unit to form a high-pressure hydrogen product stream and an inert substance enriched off-gas stream.

[0059] In some embodiments, the carbon enriched off-gas stream is introduced into a membrane separation unit to form a permeate stream enriched in hydrogen and a residue stream enriched in carbon monoxide and methane. In this case, recycling the carbon enriched off-gas stream to the hydrogen production process unit includes recycling the residue stream to the hydrogen production process unit. The permeate stream can optionally be combined with the inert gas enriched stream.

[0060] The process for generating the hydrogen enriched gas stream can be integrated with a bioregenerable conversion process for making hydrocarbon products from a bioregenerable feedstock, which is considered in more detail below. In this case, a purge gas stream containing hydrogen from the bioregenerable conversion process can be introduced into the membrane separation unit. Additionally, at least a portion of the feed stream to the hydrogen production process can include a hydrocarbon-containing stream from the bioregenerable conversion process.

[0061] Another aspect of the present invention includes a process for generating a hydrogen-enriched gas stream. In one embodiment, the process comprises treating a feed stream containing a hydrocarbon or carbonaceous feedstock within a hydrogen production process unit to produce a synthesis gas mixture containing hydrogen, carbon monoxide, methane, water, and an inert gas; performing a water gas shift process on the synthesis gas mixture to form a shifted synthesis gas containing carbon dioxide; performing a hydrogen pressure swing adsorption (PSA) separation process and a carbon dioxide separation process on the shifted synthesis gas to form a high-pressure hydrogen production stream containing hydrogen, an inert gas-enriched offgas stream from the hydrogen separation process containing an inert gas and depleted of carbon-containing components, a carbon dioxide production stream containing carbon dioxide, and a carbon-enriched offgas stream containing carbon monoxide and methane, wherein the hydrogen PSA process includes forming by including a three-product PSA system comprising a three-product PSA unit or at least two PSA units; recycling the carbon-enriched offgas stream to the hydrogen production process unit; and a carbon dioxide recovery system comprising an amine separation unit, or a cryogenic separation unit, or a carbon dioxide PSA unit, or a combination thereof, and performing the hydrogen PSA separation process and the carbon dioxide separation process includes introducing the shifted synthesis gas into a three-product PSA system to form a high-pressure hydrogen production stream, an inert gas-enriched offgas stream, and a hydrogen-depleted tail gas stream; introducing the hydrogen-depleted tail gas stream into the carbon dioxide recovery system to form a carbon dioxide production stream and a carbon-enriched offgas stream, or introducing the shifted synthesis gas into the carbon dioxide recovery system to form a carbon dioxide production stream and a carbon dioxide-depleted stream; and introducing the carbon dioxide-depleted stream into the three-product PSA system to form a high-pressure hydrogen stream, an inert gas-enriched offgas stream, and a carbon-enriched offgas stream.

[0062] In some embodiments, performing a hydrogen PSA separation process and a carbon dioxide separation process comprises introducing shift synthesis gas into a three-product PSA system to form a high-pressure hydrogen product stream, an inert gas-enriched offgas stream, and a hydrogen-depleted tailgas stream, and introducing the hydrogen-depleted tailgas stream into a carbon dioxide recovery system to form a carbon dioxide product stream and a carbon-enriched offgas stream.

[0063] In some embodiments, the process further comprises introducing the carbon-enriched offgas stream into a membrane separation unit to form a permeate stream enriched in hydrogen and a residue stream enriched in carbon monoxide and methane, and optionally combining the permeate stream with an inert gas-enriched stream, and recycling the carbon-enriched offgas stream to a hydrogen production process unit includes recycling the residue stream to a hydrogen production process unit.

[0064] In some embodiments, performing a PSA separation process and a carbon dioxide separation process comprises introducing shift synthesis gas into a carbon dioxide recovery system to form a carbon dioxide product stream and a carbon dioxide-depleted stream, and introducing the carbon dioxide-depleted stream into a three-product PSA system to form a high-pressure hydrogen stream, an inert-enriched offgas stream, and a carbon-enriched offgas stream.

[0065] In some embodiments, the process further comprises introducing the carbon-enriched offgas stream into a membrane separation unit to form a permeate stream enriched in hydrogen and a residue stream enriched in carbon monoxide and methane, and optionally combining the permeate stream with an inert gas-enriched stream, and recycling the carbon-enriched offgas stream to a hydrogen production process unit includes recycling the residue stream to a hydrogen production process unit.

[0066] FIG. 2 is a diagram of a process 300 for generating a hydrogen-enriched gas stream in which hydrogen separation is performed before carbon dioxide separation. A feed stream 305 is introduced into a hydrogen production process unit 310 where it is converted to synthesis gas. The synthesis gas mixture includes hydrogen, carbon monoxide, methane, water, and an inert gas.

[0067] A syngas stream 315 containing a syngas mixture is sent to a water gas shift reactor 320 to convert carbon monoxide to carbon dioxide.

[0068] The shifted syngas stream 325 is sent to a hydrogen PSA system 330. The hydrogen PSA system 330 can be either a three-product PSA unit or at least two PSA units, as discussed above.

[0069] The hydrogen PSA system 330 produces a high-pressure hydrogen product stream 335, an inert gas-enriched offgas stream 340, and a hydrogen-depleted tail gas stream 345. The high-pressure hydrogen product stream 335 is recovered. The inert gas-enriched offgas stream 340 is enriched in inert gases such as nitrogen and argon and depleted in carbon-containing components such as carbon dioxide, carbon monoxide, and methane. The inert gas-enriched offgas stream 340 also contains hydrogen and can be sent for use as fuel in a hydrogen production process unit or elsewhere. The hydrogen-depleted tail gas stream 345 is enriched in carbon dioxide, carbon monoxide, and methane.

[0070] The hydrogen-depleted tail gas stream 345 is sent to a carbon dioxide recovery system 350 where it is separated into a carbon dioxide product stream 355 and a carbon-enriched offgas stream 360. The carbon dioxide product stream 355 is recovered.

[0071] The carbon-enriched offgas stream 360 is recycled to the hydrogen production process unit 310.

[0072] FIG. 3 shows a process 300' in which the carbon-enriched offgas stream 360 undergoes further separation.

[0073] The carbon-enriched offgas stream 360 is sent to a membrane separation unit 365 where it is separated into a permeate stream 370 enriched in hydrogen and a residue stream 375 enriched in carbon monoxide and methane. The permeate stream 370 can optionally be combined with the inert gas-enriched offgas stream 340. The residue stream 375 enriched in carbon monoxide and methane is recycled to the hydrogen production process unit 310.

[0074] When the hydrogen production process is integrated with a bio-renewable conversion process for making hydrocarbon products from bio-renewable feedstocks, a purge gas stream 380 containing hydrogen from the bio-renewable conversion process can be introduced into the membrane separation unit 365. Additionally, a hydrocarbon-containing stream 385 from the bio-renewable conversion process (not shown) can be used as at least a portion of the feed to the hydrogen production process unit 310.

[0075] FIG. 4 is a diagram of a process 400 for generating a hydrogen-enriched gas stream in which carbon dioxide separation is performed prior to hydrogen separation. A feed stream 405 is introduced into a hydrogen production process unit 410 where it is converted to synthesis gas. The synthesis gas mixture contains hydrogen, carbon monoxide, methane, water, and an inert gas.

[0076] A synthesis gas stream 415 containing the synthesis gas mixture is sent to a water gas shift reactor 420 to convert carbon monoxide to carbon dioxide.

[0077] The shifted synthesis gas stream 425 is sent to a carbon dioxide recovery unit 430 where it is separated into a carbon dioxide product stream 435 and a carbon dioxide depleted stream 440. The carbon dioxide product stream 435 is recovered.

[0078] The carbon dioxide depleted stream 440 is sent to a hydrogen PSA system 445 where it is separated into a high pressure hydrogen product stream 450, an inert gas enriched offgas stream 455, and a carbon enriched offgas stream 460. The high pressure hydrogen product stream 450 is recovered. The inert gas enriched offgas stream 455 can be sent for use as fuel in a hydrogen production process unit or elsewhere. The carbon enriched offgas stream 460, which is enriched in carbon monoxide and methane, is recycled to the hydrogen production process unit 410.

[0079] Figure 5 shows a process 400' in which the carbon enriched offgas stream 460 undergoes further separation.

[0080] The carbon enriched offgas stream 460 is sent to a membrane separation unit 465 where it is separated into a permeate stream 470 enriched in hydrogen and a residue stream 475 enriched in carbon monoxide and methane. The permeate stream 470 can optionally be combined with the inert gas enriched offgas stream 455. The residue stream 475 is recycled to the hydrogen production process unit 410.

[0081] When the hydrogen production process is integrated with a bioregenerable conversion process for making hydrocarbon products from a bioregenerable feedstock, a purge gas stream 480 containing hydrogen from the bioregenerable conversion process can be introduced into the membrane separation unit 465. Additionally, a hydrocarbon containing stream 485 from a bioregenerable conversion process (not shown) can be used as at least part of the feed to the hydrogen production process unit 410.

Example

[0082] A computer simulation was performed on the steam reforming hydrogen production process according to the embodiment of FIG. 3. The feed stream 305 to this steam reformer was a hydrocarbon containing stream 385 (e.g., naphtha) from natural gas and a bioregenerable process. Additionally, a hydrogen containing purge gas stream 380 from the bioregenerable process was combined with the carbon enriched offgas stream 360 to the membrane separation unit 365. The natural gas feed stream 305 contained an inert component (nitrogen).

[0083] To optimize the system design, the residual stream 375 enriched in carbon monoxide and methane is recycled to the hydrogen production unit (e.g., steam reforming reactor) 310 while minimizing CO2 emissions from the process and maximizing the recovery of hydrogen and CO2. The results are shown in Table 1 below. Comparing the inert gas enriched offgas stream 340 with the shifted syngas stream 325, it can be seen that 38% of the nitrogen in the shifted syngas stream 325 is removed into the offgas stream 340, while only 0.5% of the carbon monoxide and 0.7% of the methane in the shifted syngas are present. Further, the membrane separation unit 365 selectively removes hydrogen from the recycle loop, producing a residual stream 375 enriched in carbon monoxide and methane.

[0084]

Table 1

[0085] Specific Embodiments The following is described in conjunction with specific embodiments, it being understood that this description is illustrative of the foregoing description and the scope of the appended claims and is not intended to limit them.

[0086] The first embodiment of the present invention is a process for producing a hydrogen-enriched product, which comprises treating a feed stream containing a hydrocarbon or carbonaceous feedstock in a hydrogen production process unit to produce a synthesis gas mixture containing hydrogen, carbon monoxide, methane, water, and an inert gas; performing a water gas shift process on the synthesis gas mixture to form a shifted synthesis gas containing carbon dioxide; performing a hydrogen pressure swing adsorption (PSA) separation process and a carbon dioxide separation process on the shifted synthesis gas to form a high-pressure hydrogen product stream containing hydrogen, an inert gas-enriched offgas stream containing an inert gas and depleted of carbon-containing components from the hydrogen separation process, a carbon dioxide product stream containing carbon dioxide, and a carbon-enriched offgas stream containing carbon monoxide and methane, wherein the hydrogen PSA process comprises forming the high-pressure hydrogen product stream, the inert gas-enriched offgas stream, and the carbon-enriched offgas stream by including a three-product PSA unit or a three-product PSA system comprising at least two PSA units; and recycling the carbon-enriched offgas stream to the hydrogen production process unit. One embodiment of the present invention is that performing the hydrogen PSA separation process and the carbon dioxide separation process includes introducing the shifted synthesis gas into a three-product PSA to form a high-pressure hydrogen product stream, an inert gas-enriched offgas stream, and a hydrogen-depleted tail gas stream; and introducing the hydrogen-depleted tail gas stream into carbon dioxide recovery to form a carbon dioxide product stream and a carbon-enriched offgas stream, which is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention is that introducing the shifted synthesis gas into a three-product PSA system includes introducing the shifted synthesis gas into a three-product PSA unit to form a high-pressure hydrogen product stream, an inert gas-enriched offgas stream, and a hydrogen-depleted tail gas stream, which is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph.One embodiment of the present invention is that introducing shift syngas into a three-product PSA system includes introducing the shift syngas into a first PSA unit to form a carbon component-enriched tail gas stream enriched in carbon dioxide, carbon monoxide, and methane, and a hydrogen-enriched intermediate stream, introducing the hydrogen-enriched intermediate stream into a second PSA unit to form a high-pressure hydrogen product stream and an inert substance-enriched offgas stream, and introducing the carbon component-enriched tail gas stream into carbon dioxide recovery, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention further includes introducing a carbon-enriched offgas stream into a membrane separation unit to form a permeate stream enriched in hydrogen and a residual stream enriched in carbon monoxide and methane, and optionally combining the permeate stream with an inert gas-enriched stream, and recycling the carbon-enriched offgas stream to a hydrogen production process unit includes recycling the residual stream to a hydrogen production process unit, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention further includes introducing a purge gas stream containing hydrogen from a bioregenerable conversion process for producing hydrocarbon products from a bioregenerable feedstock into the membrane separation unit together with the carbon-enriched offgas stream, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention is that performing a PSA separation process and a carbon dioxide separation process includes introducing shift syngas into carbon dioxide recovery to form a carbon dioxide product stream and a carbon dioxide-depleted stream, and introducing the carbon dioxide-depleted stream into a three-product PSA to form a high-pressure hydrogen stream, an inert substance-enriched offgas stream, and a carbon-enriched offgas stream, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph.One embodiment of the present invention is that introducing a carbon dioxide-depleted stream into a three-product PSA system involves introducing the carbon dioxide-depleted stream into a three-product PSA unit to form a high-pressure hydrogen product stream, an inert gas-enriched offgas stream, and a carbon-enriched offgas stream, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention is that introducing a carbon dioxide-depleted stream into a three-product PSA system involves introducing the carbon dioxide-depleted stream into a first PSA unit to form a carbon-enriched offgas stream and a hydrogen-enriched intermediate stream, and introducing the hydrogen-enriched intermediate stream into a second PSA unit to form a high-pressure hydrogen product stream and an inert-substance-enriched offgas stream, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention further includes introducing the carbon-enriched offgas stream into a membrane separation unit to form a permeate stream enriched in hydrogen and a residue stream enriched in carbon monoxide and methane, and optionally combining the permeate stream with an inert gas-enriched stream, and recycling the carbon-enriched offgas stream to a hydrogen production process unit includes recycling the residue stream to a hydrogen production process unit, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention further includes introducing a purge gas stream containing hydrogen from a bioregenerable conversion process for producing hydrocarbon products from a bioregenerable feedstock into the membrane separation unit together with the carbon-enriched offgas stream, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph. One embodiment of the present invention is that the hydrogen production process unit comprises a steam reforming unit with an optional gas heating reformer, an autothermal reforming unit with an optional gas heating reformer, or a gasification unit, or a partial oxidation (POX) unit, or a combination thereof, and is one, any, or all of the preceding embodiments of this paragraph including the first embodiment of this paragraph.In one embodiment of the present invention, the amount of the carbon-enriched offgas stream recycled to the hydrogen production process unit includes less than 80% of the total amount of the carbon-enriched offgas stream and the inert gas-enriched offgas stream, and is one, any, or all of the preceding embodiments of this paragraph up to the first embodiment of this paragraph. In one embodiment of the present invention, carbon dioxide recovery comprises an amine separation unit, or a cryogenic separation unit, or a carbon dioxide PSA unit, or a combination thereof, and is one, any, or all of the preceding embodiments of this paragraph up to the first embodiment of this paragraph. Embodiments of the present invention include that at least a portion of the feed stream includes a hydrocarbon-containing stream from a bioregenerable conversion process for producing hydrocarbon products from a bioregenerable feedstock, and is one, any, or all of the preceding embodiments of this paragraph up to the first embodiment of this paragraph.

[0087] A second embodiment of the present invention is a process for producing a hydrogen-enriched product, comprising treating a feed stream containing a hydrocarbon or carbonaceous feedstock in a hydrogen production process unit to produce a syngas mixture containing hydrogen, carbon monoxide, methane, water, and an inert gas; performing a water gas shift process on the syngas mixture to form a shifted syngas containing carbon dioxide; performing a hydrogen pressure swing adsorption (PSA) separation process and a carbon dioxide separation process on the shifted syngas to form a high-pressure hydrogen product stream containing hydrogen, an inert gas-enriched offgas stream containing an inert gas and depleted of carbon-containing components from the hydrogen separation process, a carbon dioxide product stream containing carbon dioxide, and a carbon-enriched offgas stream containing carbon monoxide and methane, wherein the hydrogen PSA process comprises forming using a three-product PSA unit or a three-product PSA system comprising at least two PSA units; recycling the carbon-enriched offgas stream to the hydrogen production process unit; and carbon dioxide recovery comprising an amine separation unit, or a cryogenic separation unit, or a carbon dioxide PSA unit, or a combination thereof, and performing the hydrogen PSA separation process and the carbon dioxide separation process comprises introducing the shifted syngas into a three-product PSA to form a high-pressure hydrogen product stream, an inert gas-enriched offgas stream, and a hydrogen-depleted tail gas stream; introducing the hydrogen-depleted tail gas stream into carbon dioxide recovery to form a carbon dioxide product stream and a carbon-enriched offgas stream, or introducing the shifted syngas into carbon dioxide recovery to form a carbon dioxide product stream and a carbon dioxide-depleted stream; and introducing the carbon dioxide-depleted stream into a three-product PSA to form a high-pressure hydrogen stream, an inert substance-enriched offgas stream, and a carbon-enriched offgas stream. An embodiment of the present invention is that performing the hydrogen PSA separation process and the carbon dioxide separation process comprises introducing the shifted syngas into a three-product PSA to form a high-pressure hydrogen product stream, an inert gas-enriched offgas stream, and a hydrogen-depleted tail gas stream; and introducing the hydrogen-depleted tail gas stream into carbon dioxide recovery to form a carbon dioxide product stream and a carbon-enriched offgas stream, and includes any one, or all, of the preceding embodiments of this paragraph up to the second embodiment of this paragraph.One embodiment of the present invention includes introducing a carbon-enriched off-gas stream into a membrane separation unit to form a permeate stream enriched in hydrogen and a residue stream enriched in carbon monoxide and methane, and optionally combining the permeate stream with an inert gas-enriched stream. Recycling the carbon-enriched off-gas stream to a hydrogen production process unit includes recycling the residue stream to the hydrogen production process unit, and is one, any, or all of the preceding embodiments of this paragraph including the second embodiment of this paragraph. One embodiment of the present invention includes performing a PSA separation process and a carbon dioxide separation process, introducing shift syngas into carbon dioxide recovery to form a carbon dioxide product stream and a carbon dioxide-depleted stream, and introducing the carbon dioxide-depleted stream into a three-product PSA to form a high-pressure hydrogen stream, an inert-material-enriched off-gas stream, and a carbon-enriched off-gas stream, and is one, any, or all of the preceding embodiments of this paragraph including the second embodiment of this paragraph. One embodiment of the present invention includes introducing a carbon-enriched off-gas stream into a membrane separation unit to form a permeate stream enriched in hydrogen and a residue stream enriched in carbon monoxide and methane, and optionally combining the permeate stream with an inert gas-enriched stream. Recycling the carbon-enriched off-gas stream to a hydrogen production process unit includes recycling the residue stream to the hydrogen production process unit, and is one, any, or all of the preceding embodiments of this paragraph including the second embodiment of this paragraph.

[0088] Without further elaboration, using the foregoing description, those skilled in the art should be able to utilize the present invention to its fullest extent without departing from the spirit and scope of the present invention, and can easily identify the essential characteristics of the present invention, make various changes and modifications to the present invention, and adapt it to various uses and conditions. Therefore, the preceding preferred specific embodiments should be construed as illustrative only and not as limiting the remainder of the disclosure in any way, and are intended to cover various modifications and equivalent configurations within the scope of the appended claims.

[0089] In the above, all temperatures are described in degrees Celsius, and all parts and percentages are by weight unless otherwise indicated.

Claims

1. A process for generating a hydrogen-enriched gas stream, comprising: processing a feed stream (305) containing a hydrocarbon or carbonaceous feedstock in a hydrogen generation process unit (310) to produce a synthesis gas mixture containing hydrogen, carbon monoxide, methane, water, and an inert gas; performing a water gas shift process on the synthesis gas mixture (315) to form a shifted synthesis gas (325) containing carbon dioxide; performing a hydrogen pressure swing adsorption (PSA) separation process and a carbon dioxide separation process on the shifted synthesis gas (325) to form a high-pressure hydrogen production stream (335) containing hydrogen, an inert gas-enriched offgas stream (340) from the hydrogen separation process containing the inert gas and depleted of carbon-containing components, a carbon dioxide production stream (355) containing carbon dioxide, and a carbon-enriched offgas stream (360) containing the carbon monoxide and the methane, wherein the hydrogen PSA process includes a three-product PSA unit or a three-product PSA system (330) comprising at least two PSA units; recycling the carbon-enriched offgas stream (360) to the hydrogen generation process unit (310).

2. Performing the hydrogen PSA separation process and the carbon dioxide separation process comprises: introducing the shifted synthesis gas (325) into the three-product PSA system (330) to form the high-pressure hydrogen production stream (335), the inert gas-enriched offgas stream (340), and a hydrogen-depleted tail gas stream (345); introducing the hydrogen-depleted tail gas stream (345) into a carbon dioxide recovery system (350) to form the carbon dioxide production stream (355) and the carbon-enriched offgas stream (360). The process according to claim 1.

3. Introducing the shifted synthesis gas (325) into the three-product PSA system (330) comprises: introducing the shifted synthesis gas (325) into the three-product PSA unit to form the high-pressure hydrogen production stream (335), the inert gas-enriched offgas stream (340), and the hydrogen-depleted tail gas stream (345). The process according to claim 2.

4. Introducing the shifted synthesis gas (325) into the three-product PSA system (330) comprises: Introduce the shift syngas (330) into a first PSA unit to form a carbon component-enriched tail gas stream enriched in carbon dioxide, carbon monoxide, and methane, and a hydrogen-enriched intermediate stream; Introduce the hydrogen-enriched intermediate stream into a second PSA unit to form the high-pressure hydrogen product stream (335) and an inert substance-enriched off-gas stream (340); Introduce the carbon component-enriched tail gas stream into the carbon dioxide recovery system (345), the process according to claim 2.

5. Introduce the carbon-enriched off-gas stream (360) into a membrane separation unit (365) to form a permeate stream (370) enriched in hydrogen and a residual stream (375) enriched in carbon monoxide and methane; Optionally, combine the permeate stream (370) with the inert gas-enriched stream (340); Optionally, further include introducing a purge gas stream (380) containing hydrogen from a bioregenerable conversion process for producing hydrocarbon products from a bioregenerable feedstock into the membrane separation unit (365); Recycling the carbon-enriched off-gas stream (360) to the hydrogen production process unit includes recycling the residual stream (375) to the hydrogen production process unit (310), the process according to claim 2.

6. Performing the PSA separation process and the carbon dioxide separation process; Introduce the shift syngas (425) into a carbon dioxide recovery system (430) to form a carbon dioxide product stream (435) and a carbon dioxide-depleted stream (440); Introduce the carbon dioxide-depleted stream (440) into the three-product PSA system (445) to form a high-pressure hydrogen stream (450), an inert substance-enriched off-gas stream (455), and the carbon-enriched off-gas stream (460), the process according to claim 1.

7. Introducing the carbon dioxide-depleted stream (440) into the three-product PSA system (445); Introduce the carbon dioxide-depleted stream (440) into the three-product PSA unit to form the high-pressure hydrogen product stream (450), the inert gas-enriched off-gas stream (455), and the carbon-enriched off-gas stream (460), the process according to claim 6.

8. Introducing the carbon dioxide-depleted stream (440) into the three-product PSA system (445); Introduce the carbon dioxide depleted stream (440) into the first PSA unit to form the carbon enriched offgas stream (460) and the hydrogen enriched intermediate stream; Introduce the hydrogen enriched intermediate stream into the second PSA unit to form the high pressure hydrogen product stream (450) and the inert material enriched offgas stream (455), the process according to claim 6. **Claim 9** Introduce the carbon enriched offgas stream (460) into the membrane separation unit (465) to form a permeate stream (470) enriched in hydrogen and a residue stream (475) enriched in carbon monoxide and methane; Optionally, combine the permeate stream (470) with the inert gas enriched stream (455); Optionally, further include introducing a purge gas stream (480) containing hydrogen from a bioregenerable conversion process for producing hydrocarbon products from a bioregenerable feedstock into the membrane separation unit (465); The process according to claim 6, wherein recycling the carbon enriched offgas stream (460) to the hydrogen production process unit (410) includes recycling the residue stream (475) to the hydrogen production process unit (410). **Claim 10** The process according to claim 1, wherein the carbon dioxide recovery system (350) includes an amine separation unit, or a cryogenic separation unit, or a carbon dioxide PSA unit, or a combination thereof.

Images