Method for increasing hydrogen recovery by cooling hydrogen with the product CO2 stream

Abstract

A process for increasing hydrogen recovery is described. The process uses a cryogenic carbon dioxide-rich product from a carbon dioxide recovery system to cool a hydrogen PSA feed stream. The carbon dioxide-rich product stream comprises a supercritical carbon dioxide stream or a liquid carbon dioxide stream. The synthesis gas stream is typically cooled to a temperature in the range of 0°C to 40°C. The temperature of the cooled synthesis gas stream is typically at least 10°C lower than the temperature of the synthesis gas before cooling.

Description

[Technical Field]

[0001] (Priority statement) This application claims the benefit of and priority to U.S. Patent Application No. 18 / 056,748, filed November 18, 2022, which is incorporated herein by reference in its entirety. [Background technology]

[0002] Hydrogen is expected to have significant growth potential because it is a clean-burning fuel. However, hydrogen production has traditionally been a significant source of CO2 emissions, and government regulations and societal pressures are increasingly taxing or penalizing CO2 emissions or encouraging CO2 capture. As a result, significant competition is expected to drive down the cost of hydrogen production while capturing the by-product CO2 for subsequent geological sequestration in order to capture the growing market. While CO2 can be separated as steam that is fed into common pipelines, the current lack of CO2 pipeline infrastructure in certain parts of the world will likely require it to be produced in a liquefied form for easy transportation by truck or ship.

[0003] The desired level of CO2 emission reduction depends on local economic conditions, with some hydrogen producers prioritizing maximizing hydrogen production through CO2 capture, others prioritizing minimizing CO2 emissions from hydrogen production, and some somewhere in between. Another important factor is the reformer technology selected for a given hydrogen production unit. In a steam reforming plant, 50% to 60% CO2 capture may be sufficient, while in an autothermal reformer (ATR), gasifier, or partial oxidation (POX) reformer, greater than 90% or even 95% can be expected.

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

[0005] U.S. Patent No. 8,021,464 describes a process for the combined production of hydrogen and CO2 from a mixture of hydrocarbons that is converted to synthesis gas. The synthesis gas is separated in a pressure swing adsorption (PSA) unit into a hydrogen-rich stream and a PSA off-gas stream. The PSA off-gas is compressed and dried, followed by several successive steps of condensing and separating a CO2-rich condensate, with the temperature being reduced with each step, the temperature of which ranges from ambient to -56°C. However, this process results in a purge stream containing significant amounts of CO2 that must be removed from the process. A permeate module can be used to improve separation, but at the cost 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 including a reformer unit, an optional water-gas shift reactor, a PSA unit, and a cryogenic purification unit or catalytic oxidation device. The PSA unit produces three streams: a high-pressure hydrogen stream, a low-pressure CO2 stream, and a CH4-rich stream that is removed during a CO2 co-purge step. 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 in 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. The use of a second high-pressure feed stream (the 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) and have isolation valves between the two vessels and the intermediate side draw further increases the cost and complexity of the process.

[0007] Therefore, there is a need for improved hydrogen production processes with improved cost-effective hydrogen recovery. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram of one embodiment of a method for producing hydrogen and capturing CO2 from a hydrogen production process. [Figure 2] FIG. 1 is a diagram of another embodiment of a method for producing hydrogen and capturing CO2 from a hydrogen production process. DETAILED DESCRIPTION OF THE INVENTION

[0009] The process uses cold product CO2 from the carbon dioxide capture system to cool the hydrogen PSA feed stream. Reducing the temperature of the PSA feed stream increases the equilibrium capacity of the adsorbed components, resulting in a reduced PSA bed volume and increased hydrogen recovery. This causes a small but significant reduction in overall compression effort due to greater hydrogen recovery and reduced tail gas temperature. Additional benefits include greater removal of methanol in the condensate, thereby reducing trace methanol concentrations to downstream dehydration units (methanol can be problematic in dryers due to coking and reduced adsorbent life), and reduced hydrogen product temperature, potentially eliminating the product cooler (customers often have maximum hydrogen product temperature specifications, e.g., 40-50°C).

[0010] The refrigeration is often essentially "free," i.e., refrigeration not recovered from the process remains at the system boundary in the product CO stream. The only additional equipment is a heat exchanger to cross-exchange the low temperature, high pressure CO stream with the shifted syngas, and a knock-out pot to remove water condensate.

[0011] The hydrogen production process includes a syngas production zone that produces syngas, which may comprise a new or existing syngas reactor, such as, but not limited to, a steam reforming unit with an optional gas-heated reformer, an autothermal reforming unit with an optional gas-heated reformer, a gasification unit, or a partial oxidation (POX) unit, or combinations thereof.

[0012] The synthesis gas reactor produces an effluent comprising a mixture of hydrogen, carbon dioxide, water, and gases including at least one of methane, carbon monoxide, nitrogen, and argon.

[0013] The synthesis gas reactor is typically followed by a water gas shift (WGS) unit to convert carbon monoxide to carbon dioxide. The effluent stream leaving the WGS unit is typically between 220°C and 420°C.

[0014] Heat is recovered from the WGS effluent stream (e.g., to generate steam), and the effluent stream is then further cooled, typically using an air or water chiller, to a temperature of 35° C. to 60° C. The temperature is limited by the temperature of the air or water used in the chiller.

[0015] The effluent stream from the synthesis gas production zone is sent to a cooler where it exchanges heat with a carbon dioxide-enriched product stream from a carbon dioxide capture system. The cooler comprises a heat exchanger, such as a shell-and-tube type. The carbon dioxide stream may be on the tube side of the heat exchanger and the effluent stream on the shell side. The carbon dioxide-enriched product stream cools the synthesis gas effluent stream to a temperature in the range of 0°C to 40°C, or 0°C to 35°C, or 5°C to 40°C, or 5°C to 35°C. The temperature is typically at least 10°C lower than the temperature of the synthesis gas before cooling.

[0016] The cooled synthesis gas stream is sent to a hydrogen pressure swing adsorption (PSA) unit for separation into a hydrogen-rich high-pressure hydrogen stream and a hydrogen-depleted tail gas stream containing the remaining hydrogen, carbon dioxide, water, and at least one of methane, carbon monoxide, nitrogen, and argon. The high-pressure hydrogen stream typically contains 85% to 90% of the hydrogen in the effluent, which is recovered.

[0017] The hydrogen-depleted tail gas stream is compressed, dried, and sent to a CO2 capture system where it is separated into a CO2-enriched product stream and an overhead stream containing hydrogen and some carbon dioxide, as well as some of at least one of methane, carbon monoxide, nitrogen, and argon.

[0018] The overhead stream is sent to a second PSA unit which produces a low-pressure CO stream enriched in carbon dioxide and an off-gas stream enriched in hydrogen and at least one of carbon monoxide, methane, nitrogen, and argon.

[0019] The off-gas stream may be sent to a second PSA unit (not shown) for separation into an additional purified high-pressure hydrogen product stream and a low-pressure exhaust gas stream, which can be burned as fuel, recycled to the syngas production unit, or both. Alternatively, the off-gas stream may be sent to a gas turbine or co-generation system to generate electricity and / or steam. Another possibility is to send the off-gas stream to a membrane separation unit that hydrogen-enriches the permeate, which can be used as a clean fuel product, and recycles the residue to the syngas production unit.

[0020] The low pressure CO2 stream may be combined with a low pressure exhaust gas stream from the hydrogen PSA unit and recycled to the CO2 capture system.

[0021] The CO2 capture unit may comprise an amine separation unit with a CO2 chiller and liquefaction system, or a cryogenic fractionation unit, or a carbon dioxide PSA unit with a CO2 chiller and liquefaction system, or a combination thereof. The cooling capacity of these different types of CO2 capture units is generally provided by a mechanical refrigeration system using a suitable refrigerant and a vapor compression cycle. In some cases, a mixed refrigerant may be used to minimize compression forces. For example, a ternary mixed refrigerant containing propane, isopentane, and carbon dioxide may be used.

[0022] The CO2-rich product stream is used to cool the shifted syngas upstream of the hydrogen PSA unit. The CO2-rich product stream comprises supercritical carbon dioxide or liquid carbon dioxide. The liquid carbon dioxide is subcooled, meaning that its temperature is below the bubble point (i.e., saturation temperature) of the CO2-rich product stream. The pressure of the supercritical CO2 product stream entering the syngas cooler can range from 100 bar(g) to 200 bar(g) and its temperature is 0°C to 20°C. The pressure of the subcooled liquid CO2 product stream entering the syngas cooler can range from 10 bar(g) to 20 bar(g) and its temperature is -30°C to -50°C. The CO2 product stream can comprise greater than 95 mol% CO2, or greater than 99 mol% CO2, or greater than 99.9 mol% CO2.

[0023] In some embodiments, the shifted syngas stream from the syngas production zone is separated in an amine-based carbon dioxide capture unit into a carbon dioxide-depleted syngas stream and a carbon dioxide-rich stream. The carbon dioxide-rich stream is compressed, dried, and liquefied. The liquefied carbon dioxide stream is used to cool the carbon dioxide-depleted syngas stream and recovered. Water is removed from the cooled carbon dioxide-depleted syngas stream. The resulting cooled carbon dioxide-depleted syngas stream is sent to a hydrogen PSA unit for separation into a high-pressure hydrogen product stream and a tail gas stream.

[0024] 1 illustrates one embodiment of a process 100 for producing a hydrogen-rich high-pressure hydrogen product stream and a carbon dioxide-enriched product stream. A feed stream 105 is introduced into a hydrogen production process unit 110 where it is converted to synthesis gas. The synthesis gas mixture includes hydrogen, carbon monoxide, carbon dioxide, methane, water, and inert gases. The synthesis gas mixture is sent to a water-gas shift reactor within the hydrogen production process unit 110 to convert the carbon monoxide to carbon dioxide.

[0025] The shifted syngas stream 115 may have a temperature of 35° C. to 60° C. and a pressure of 20 bar(g) to 40 bar(g). The shifted syngas may contain 70-80 mole % hydrogen, 15-25 mole % carbon dioxide, 1-4 mole % methane, 0.5-3 mole % carbon monoxide, 0-0.5 mole % nitrogen, 0.2-0.6 mole % water (saturates), 0-0.2 mole % argon, and 0-500 ppmv methanol.

[0026] The shifted syngas stream 115 is passed to a heat exchanger 120 where it is cooled by contact with a carbon dioxide-enriched product stream 125 comprising supercritical carbon dioxide or liquid carbon dioxide, as described below.

[0027] Cooled syngas stream 130, having a temperature between 0°C and 40°C, is sent to knockout pot 135 where water stream 140 is removed, resulting in a cooled syngas stream 145 having a lower water level than the incoming cooled syngas stream 130. If methanol is present in shifted syngas stream 115, a portion of the methanol is removed with water stream 140.

[0028] The cooled synthesis gas stream 145 is sent to a hydrogen PSA unit 150 where it is separated into a high pressure hydrogen product stream 155 and a low pressure hydrogen depleted tail gas stream 160 .

[0029] High pressure hydrogen product stream 155 may have a temperature of 40-65°C and a pressure of 20-40 bar(g), and may contain 99.0-99.999 mole % hydrogen, less than 1 ppmv carbon dioxide, less than 1 ppmv to 1000 ppmv methane, less than 1 ppmv to 50 ppmv carbon monoxide, 0-2000 ppmv nitrogen, less than 1 ppmv water, 0-3000 ppmv argon, and less than 0.1 ppmv methanol.

[0030] The low pressure hydrogen-depleted tail gas stream 160 may have a temperature of 20-40°C and a pressure of 0.2-0.5 bar(g), and may contain 20-30 molar % hydrogen, 50-70 molar % carbon dioxide, 2-15 molar % methane, 1-15 molar % carbon monoxide, 0-2 molar % nitrogen, 1-2 molar % water, 0-0.4 molar % argon, and 0-1000 ppmv methanol.

[0031] Low pressure hydrogen-depleted flue gas stream 160 is compressed in compressor 165 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. Compressed flue gas stream 170 is dried in dryer 175, and compressed, dried flue gas stream 180 is sent to CO2 capture unit 185 where it is separated into carbon dioxide-enriched product stream 125 and an overhead stream 190. Carbon dioxide-enriched product stream 125, which comprises supercritical or liquid carbon dioxide, is used to cool the synthesis gas and is recovered.

[0032] The overhead stream 190 may have a temperature of 20-30°C and a pressure of 40-50 bar(g), and may contain 50-80 mole % hydrogen, 10-20 mole % carbon dioxide, 5-20 mole % methane, 5-20 mole % carbon monoxide, 0-20 mole % nitrogen, and 0-1 mole % argon.

[0033] The overhead stream 190 is sent to a second PSA unit 195 to form a low-pressure carbon dioxide stream 200 enriched in carbon dioxide and an off-gas stream 205 enriched in hydrogen and at least one of carbon monoxide, methane, nitrogen, and argon.

[0034] The low-pressure carbon dioxide stream 200 may have a temperature of 10-20°C and a pressure of 0.3-0.5 bar(g), and may contain 10-20 molar% hydrogen, 60-80 molar% carbon dioxide, 2-10 molar% methane, 2-10 molar% carbon monoxide, 0-10 molar% nitrogen, and 0-0.5 molar% argon. The off-gas stream 205 may have a temperature of 30-40°C and a pressure of 40-50 bar(g), and may contain 50-90 molar% hydrogen, 0.01-0.5 molar% carbon dioxide, 5-30 molar% methane, 5-30 molar% carbon monoxide, 0-20 molar% nitrogen, and 0-1 molar% argon.

[0035] In some embodiments, the off-gas stream 200 is combined with the exhaust gas stream 160 and sent to the compressor 165 .

[0036] FIG. 2 shows another process 300 for producing a hydrogen-rich high-pressure hydrogen product stream and a carbon dioxide-enriched product stream.

[0037] In this embodiment, feed stream 305 is sent to synthesis gas production zone 310 where it is converted to synthesis gas and carbon monoxide is converted to carbon dioxide.

[0038] The shifted syngas stream 315 is separated in an amine-based carbon dioxide capture unit 320 into a carbon dioxide-depleted syngas stream 330 and a carbon dioxide-enriched stream 335 .

[0039] The carbon dioxide depleted synthesis gas stream 330 may have a temperature of 20-40°C and a pressure of 20-40 bar(g) and may contain 90-98 mole % hydrogen, 50 ppmv-0.5 mole % carbon dioxide, 1-5 mole % methane, 0.5-3.5 mole % carbon monoxide, 0-0.6 mole % nitrogen, 0.2-0.6 mole % water (saturated), 0-0.3 mole % argon, and no methanol.

[0040] The carbon dioxide-rich stream 335 may have a temperature of 30-50°C and a pressure of 0.3-1.0 bar(g), and may contain 0-1 mole % hydrogen, 85-95 mole % carbon dioxide, 0-0.1 mole % methane, 0-0.1 mole % carbon monoxide, 0-0.1 mole % nitrogen, 5-10 mole % water, and 0-0.1 mole % argon.

[0041] Carbon dioxide-rich stream 335 is compressed in compressor 340 and compressed carbon dioxide-rich stream 345 is dried in dryer 350. Dried, compressed carbon dioxide-rich stream 355 is liquefied in liquefaction unit 360 to form carbon dioxide-rich product stream 365.

[0042] Carbon dioxide-enriched product stream 365 is sent to heat exchanger 370 to cool carbon dioxide-depleted syngas stream 330. Cooled carbon dioxide-depleted syngas stream 375 is sent to knockout pot 380 to remove water, forming water stream 385 and cooled syngas stream 390 having a lower water level than cooled carbon dioxide-depleted syngas stream 375.

[0043] The cooled synthesis gas stream 390 is sent to a hydrogen PSA unit 395 where it is separated into a high pressure hydrogen product stream 400 and a low pressure tail gas stream 405. The high pressure hydrogen product stream 400 is as described above for the high pressure hydrogen product stream 155.

[0044] The low pressure hydrogen-depleted tail gas stream 405 has a temperature of 20-40°C and a pressure of 0.2-0.5 bar(g), and contains 70-80 mole % hydrogen, 0.1-3 mole % carbon dioxide, 2-20 mole % methane, 2-20 mole % carbon monoxide, 0-4 mole % nitrogen, 1-4 mole % water, 0-2 mole % argon, and no methanol. [Example]

[0045] An example of the process shown in Figure 1 is shown in Table 1 below for a shifted syngas stream from an autothermal reforming syngas generation unit. An air cooler was used to cool the shifted syngas stream to 60°C. After the air cooler, the shifted syngas was cooled to a temperature of 30°C with supercritical CO2 from a cryogenic CO2 fractionation process and then sent to a hydrogen PSA unit. By reducing the syngas temperature from 60°C to 30°C, the hydrogen recovery from the PSA unit increased from 86.5% to 88.5%. This benefit saved 6% of the overall compression power in the carbon capture unit. Additionally, 65% of the methanol in the syngas was removed in the water condensate stream from the knockout pot, resulting in lower methanol levels to the dryer and extended desiccant life.

[0046] [Table 1]

[0047] As used herein, the term "stream" can include a variety of hydrocarbon molecules and other substances.

[0048] As used herein, the terms "stream," "feed," "product," "portion," or "fraction" can include various hydrocarbon molecules, such as straight- and branched-chain alkanes, naphthalenes, alkenes, alkadienes, and alkynes, and, optionally, other materials, such as gases, e.g., hydrogen, or impurities, e.g., heavy metals and sulfur and nitrogen compounds. Each of the above can also include aromatic and non-aromatic hydrocarbons.

[0049] As used herein, the term "overhead stream" can mean a stream removed at or near the top of a vessel such as a column.

[0050] As used herein, the term "bottoms stream" can mean a stream removed at or near the bottom of a vessel such as a column.

[0051] As used herein, the term "unit" can refer to an area that includes one or more pieces of equipment and / or one or more subzones. Equipment can include, but is not limited to, one or more reactors or reaction vessels, separation vessels, distillation columns, heaters, exchangers, pipes, pumps, compressors, and controllers. Additionally, equipment such as reactors, dryers, or vessels can further include one or more zones or subzones.

[0052] As illustrated, the process flow lines in the diagrams may be referred to interchangeably as, for example, lines, pipes, feeds, gases, products, emissions, parts, portions, or streams.

[0053] The term "passing" means that material passes from a conduit or vessel to an object.

[0054] The terms "hydrogen-enriched" and "hydrogen-enriched stream" mean that the product stream has a higher hydrogen content / concentration than the inlet gas stream. For example, in some embodiments, the product stream may contain more than 40 mol%, or more than 50 mol%, or more than 60 mol%, or more than 70 mol%, or more than 80 mol%, or more than 90 mol%, or more than 95 mol%, or more than 98 mol%, or more than 99 mol%, or more than 99.9 mol% hydrogen.

[0055] The terms "CO2-enriched" and "CO2-enriched stream" mean that the CO2 content / concentration of the product stream is higher than that of the inlet gas stream. For example, in some embodiments, the product stream may contain more than 40 mol%, or more than 50 mol%, or more than 60 mol%, or more than 70 mol%, or more than 80 mol%, or more than 90 mol%, or more than 95 mol%, or more than 98 mol%, or more than 99 mol%, or more than 99.9 mol% CO2.

[0056] Specific Embodiments While the following will be described in conjunction with specific embodiments, it will be understood that this description is illustrative, but not intended to limit the scope of the preceding description and appended claims.

[0057] A first embodiment of the present invention is a process for increased hydrogen recovery, comprising: introducing a feed stream comprising a hydrocarbon or carbonaceous feedstock into a synthesis gas production zone comprising a synthesis gas reactor to produce a synthesis gas stream comprising hydrogen, carbon dioxide, and at least one of carbon monoxide, methane, water, nitrogen, and argon; cooling the synthesis gas stream to a temperature in the range of 0°C to 40°C with a carbon dioxide-enriched product stream from a carbon dioxide capture system to form a cooled synthesis gas stream; removing at least a portion of the water from the cooled synthesis gas stream; and introducing the cooled synthesis gas to a hydrogen pressure swing adsorption (PSA) unit to form a hydrogen-enriched high-pressure hydrogen product stream and a hydrogen-depleted tail gas stream; wherein the carbon dioxide-enriched product stream comprises a supercritical carbon dioxide stream or a liquid carbon dioxide stream. An embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising: introducing the hydrogen-depleted exhaust gas stream into a carbon dioxide capture system to form a carbon dioxide-enriched product stream and an overhead stream; separating the overhead stream in a second PSA unit to form a low-pressure carbon dioxide stream enriched in carbon dioxide and an off-gas stream enriched in hydrogen and at least one of carbon monoxide, methane, nitrogen, and argon; and optionally recycling the low-pressure carbon dioxide stream to the carbon dioxide capture system. An embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising: compressing the hydrogen-depleted exhaust gas stream to form a compressed exhaust gas stream; drying the compressed exhaust gas stream to form a dry compressed exhaust gas stream; and wherein introducing the hydrogen-depleted exhaust gas stream into the carbon dioxide capture system comprises introducing the dry compressed exhaust gas stream to the carbon dioxide capture system. One embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the carbon dioxide capture unit comprises an amine separation unit, or a cryogenic separation unit, or a carbon dioxide PSA unit, or a combination thereof.An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising separating the syngas stream into a carbon dioxide-depleted syngas stream and a carbon dioxide-rich stream in an amine-based carbon dioxide capture unit prior to cooling the syngas stream, and wherein cooling the syngas stream comprises cooling a carbon dioxide-depleted syngas stream. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, further comprising compressing the carbon dioxide-rich stream to form a compressed carbon dioxide-rich stream; drying the compressed carbon dioxide-rich stream to form a compressed, dried carbon dioxide-rich stream; and cooling and liquefying the compressed, dried carbon dioxide-rich stream to form a liquid carbon dioxide product stream. An embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the syngas reactor comprises a steam reforming unit with an optional gas-heated reformer, or an autothermal reforming unit with an optional gas-heated reformer, or a gasification unit, or a partial oxidation (POX) unit, or a combination thereof. An embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the syngas production zone further comprises at least one processing zone comprising a water-gas shift reactor, a pollutant removal zone, or a combination thereof. An embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the pollutant removal zone comprises a sulfur material removal zone. An embodiment of the present invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the syngas is cooled to a temperature in the range of 5°C to 35°C. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the temperature of the cooled syngas stream is at least 10° C. lower than the temperature of the syngas stream before cooling.An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the first embodiment of this paragraph, wherein the syngas stream further comprises methanol, and wherein removing at least a portion of the water from the cooled syngas stream further comprises removing at least a portion of the methanol from the cooled syngas stream.

[0058] A second embodiment of the present invention is a process for increased hydrogen recovery, comprising: introducing a feed stream comprising a hydrocarbon or carbonaceous feedstock into a synthesis gas production zone comprising a synthesis gas reactor to produce a synthesis gas stream comprising hydrogen, carbon dioxide, and at least one of carbon monoxide, methane, water, nitrogen, and argon; cooling the synthesis gas stream to a temperature at least 10°C below the temperature of the synthesis gas before cooling with a carbon dioxide-enriched product stream from a carbon dioxide capture system to form a cooled synthesis gas stream; removing at least a portion of the water from the cooled synthesis gas stream; and introducing the cooled synthesis gas to a hydrogen pressure swing adsorption (PSA) unit to form a hydrogen-enriched high-pressure hydrogen product stream and a hydrogen-depleted tail gas stream; wherein the carbon dioxide-enriched product stream comprises a supercritical carbon dioxide stream or a liquid carbon dioxide stream. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, further comprising: introducing the hydrogen-depleted tail gas stream into a carbon dioxide recovery system to form a carbon dioxide-enriched product stream and an overhead stream; separating the overhead stream in a second PSA unit to form a low-pressure carbon dioxide stream enriched in carbon dioxide and an off-gas stream enriched in hydrogen and at least one of carbon monoxide, methane, nitrogen, and argon; and recycling the low-pressure carbon dioxide stream to the carbon dioxide recovery system. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the synthesis gas reactor comprises a steam reforming unit with an optional gas-heated reformer, or an autothermal reforming unit with an optional gas-heated reformer, or a gasification unit, or a partial oxidation (POX) unit, or a combination thereof. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the synthesis gas production zone further comprises at least one treatment zone comprising a water-gas shift reactor, a pollutant removal zone, or a combination thereof.An embodiment of the invention is any one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, further comprising separating the syngas stream into a carbon dioxide-depleted syngas stream and a carbon dioxide-rich stream in an amine-based carbon dioxide capture unit prior to cooling the syngas stream, and wherein cooling the syngas stream comprises cooling a carbon dioxide-depleted syngas stream. An embodiment of the invention is any one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, further comprising: compressing the carbon dioxide-rich stream to form a compressed carbon dioxide-rich stream; drying the compressed carbon dioxide-rich stream to form a compressed, dried carbon dioxide-rich stream; and cooling and liquefying the compressed, dried carbon dioxide-rich stream to form a liquid carbon dioxide product stream. An embodiment of the invention is any one, any, or all of the preceding embodiments in this paragraph through the second embodiment of this paragraph, wherein the syngas is cooled to a temperature in the range of 0°C to 40°C. An embodiment of the invention is one, any, or all of the preceding embodiments of this paragraph through the second embodiment of this paragraph, wherein the syngas stream further comprises methanol, and wherein removing at least a portion of the water from the cooled syngas stream further comprises removing at least a portion of the methanol from the cooled syngas stream.

[0059] Without further elaboration, it is believed that, using the preceding description, one skilled in the art can utilize the present invention to its fullest extent and easily ascertain the essential characteristics of the present invention, and can make various changes and modifications to the present invention to adapt it to various uses and conditions, without departing from the spirit and scope of the present invention. The preceding preferred specific embodiments are, therefore, to be construed as merely illustrative, and not limitative of the remainder of the disclosure in any way, and are intended to cover various modifications and equivalent arrangements included within the scope of the appended claims.

[0060] Above, all temperatures are set forth in degrees Celsius and all parts and percentages are by weight unless otherwise indicated.

Claims

1. 1. A process for increasing hydrogen recovery, comprising: introducing a feed stream (105) comprising a hydrocarbon or carbonaceous feedstock into a synthesis gas production zone (110) comprising a synthesis gas reactor to produce a synthesis gas stream (115) comprising hydrogen, carbon dioxide, and at least one of carbon monoxide, methane, water, nitrogen, and argon; cooling said synthesis gas stream (115) to a temperature in the range of 0°C to 40°C with a carbon dioxide enriched product stream (125) from a carbon dioxide capture system (185) to form a cooled synthesis gas stream (130); removing at least a portion of said water (140) from said cooled synthesis gas stream (130); introducing the cooled synthesis gas (145) into a hydrogen pressure swing adsorption (PSA) unit (150) to form a hydrogen-enriched high-pressure hydrogen product stream (155) and a hydrogen-depleted tail gas stream (160); Including, The process wherein the carbon dioxide enriched product stream (125) comprises a supercritical carbon dioxide stream or a liquid carbon dioxide stream.

2. introducing the hydrogen-depleted tail gas stream (160) into the carbon dioxide recovery system (185) to form the carbon dioxide-enriched product stream (125) and an overhead stream (190); separating the overhead stream (190) in a second PSA unit (195) to form a low-pressure carbon dioxide stream (200) enriched in carbon dioxide and an off-gas stream (205) enriched in hydrogen and at least one of carbon monoxide, methane, nitrogen, and argon; 10. The process of claim 1, further comprising optionally recycling the low pressure carbon dioxide stream (200) to the carbon dioxide capture system (185).

3. compressing the hydrogen-depleted exhaust gas stream (160) to form a compressed exhaust gas stream (170); drying the compressed exhaust gas stream (170) to form a dry compressed exhaust gas stream (180); 3. The process of claim 2, wherein introducing the hydrogen-depleted exhaust gas stream (160) to the carbon dioxide capture system (185) comprises introducing the dry compressed exhaust gas stream (180) to the carbon dioxide capture system (185).

4. 3. The process of claim 2, wherein the carbon dioxide capture unit (185) comprises an amine separation unit, or a cryogenic separation unit, or a carbon dioxide PSA unit, or a combination thereof.

5. further comprising separating the synthesis gas stream (315) into a carbon dioxide-depleted synthesis gas stream (330) and a carbon dioxide-enriched stream (335) in an amine-based carbon dioxide capture unit (320) prior to cooling the synthesis gas stream (315); The process of claim 1 , wherein cooling the syngas stream (315) comprises cooling the carbon dioxide-depleted syngas stream (330).

6. compressing said carbon dioxide enriched stream (335) to form a compressed carbon dioxide enriched stream (345); drying the compressed carbon dioxide-rich stream (345) to form a compressed, dried carbon dioxide-rich stream (355); 6. The process of claim 5, further comprising cooling and liquefying the compressed and dried carbon dioxide-rich stream (355) to form a liquid carbon dioxide product stream (365).

7. 10. The process of claim 1, wherein the synthesis gas production zone (110) further comprises at least one treatment zone comprising a water-gas shift reactor, a pollutant removal zone, or a combination thereof.

8. The process of claim 7 , wherein the contaminant removal zone comprises a sulfur removal zone.

9. 10. The process of claim 1, wherein the temperature of the cooled syngas stream is at least 10°C lower than the temperature of the syngas stream before cooling.

10. 10. The process of claim 1, wherein the synthesis gas stream further comprises methanol, and wherein removing at least a portion of the water from the cooled synthesis gas stream further comprises removing at least a portion of the methanol from the cooled synthesis gas stream.

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