Steam-hydrocarbon reforming that reduces carbon dioxide emissions

Abstract

The low-carbon emission hydrogen production process can be achieved by first separating carbon dioxide from the reformer synthesis gas stream and subsequently purifying the carbon dioxide-depleted synthesis gas stream to produce a hydrogen product and a hydrogen-depleted tail gas stream. The hydrogen-depleted tail gas stream is then separated using a semi-permeable membrane, after which the hydrogen-enriched permeate is used as fuel in the reformer burner and the hydrogen-depleted residue is recycled to the feed.

Description

Background Art

[0001] Existing industrial processes, such as the reforming of hydrocarbon feeds to produce hydrogen and synthesis gas, will likely need to capture carbon dioxide (CO2) to mitigate the effects of climate change. Steam methane reforming (SMR) is the most common reforming technology, but uses air-fired combustion of the fuel gas to generate the heat required to drive the reforming reaction. Air-fired combustion generates flue gas in which any carbon in the fuel gas is converted to CO2 at low pressure and low concentration due to the large amount of inert nitrogen contributed by the air. Carbon capture from flue gas is costly, inefficient, and bulky. Eliminating carbon from the fuel gas with air-fired combustion enables the efficient capture of nearly 100% of the CO2 in the process by capturing the CO2 in synthesis gas having a much higher concentration and much higher pressure of CO2.

[0002] Licht et al. (US8,137,422) teach a process for reducing emissions from the SMR process by recycling a hydrogen-depleted waste stream or tail gas from the hydrogen purification step to a point upstream or downstream of the SMR and supplying a significant portion of the fuel gas with the product hydrogen.

[0003] Adamopoulos et al. (US9,517,933) teach a process for recovering hydrogen from the tail gas from the hydrogen purification step to improve overall hydrogen recovery. The non-permeate stream is recycled to a point downstream of the catalytic reformer.

[0004] Guo et al. (WO2013 / 131916) teach a process for operating an SMR process using high-pressure tail gas separated in a membrane system without using a compressor. The permeate stream is used as the fuel gas in the furnace and the non-permeate stream is recycled to the SMR feed.

[0005] Hydrogen must be produced using an SMR process that reduces CO2 emissions while minimizing the overall increase in energy costs, and is defined herein as the net energy of MJ (hydrocarbon supply and fuel consumed minus exported steam) divided by the total hydrogen products (kg). [Overview of the project]

[0006] This disclosure relates to a process and apparatus for separating tail gas from a hydrogen purification process downstream of a reformer into a hydrogen-concentrated permeable flow and a hydrogen-depleted impermeable flow using a membrane. In at least some embodiments, the hydrogen-concentrated permeable flow may then be combusted in a reformer to generate heat for a reforming reaction, and the hydrogen-depleted impermeable flow may then be recycled to an SMR process.

[0007] Embodiment 1: A process for generating a hydrogen concentrate product flow, the process comprising: reacting a reformer feed stream, which includes a hydrocarbon feestock and reactants selected from the group consisting of water and carbon dioxide, in the presence of a reforming catalyst to generate a synthesis gas flow containing hydrogen, carbon monoxide, and carbon dioxide; separating the synthesis gas flow or a flow derived from the synthesis gas flow to generate a carbon dioxide concentrate flow and a carbon dioxide depletion flow; separating the carbon dioxide depletion flow to generate a hydrogen concentrate product flow and a hydrogen depletion tail gas flow; separating the hydrogen depletion tail gas flow by selective permeation to generate a hydrogen concentrate permeation flow and a hydrogen depletion residual flow; and burning a fuel gas to supply heat to the reaction of the reformer feed stream, wherein the fuel gas includes at least a portion of the hydrogen concentrate permeation flow.

[0008] Embodiment 2: A process for generating a hydrogen concentrate product flow, the process comprising: reacting a reformer feed stream, comprising a hydrocarbon feestock and reactants selected from the group consisting of water and carbon dioxide, in the presence of a reforming catalyst to generate a synthesis gas flow containing hydrogen, carbon monoxide, and carbon dioxide; reacting the synthesis gas flow or a flow derived from the synthesis gas flow in the presence of a first shift catalyst to generate a shifted synthesis gas flow; separating the shifted synthesis gas flow to generate a carbon dioxide concentrate flow and a carbon dioxide depletion flow; separating the carbon dioxide depletion flow to generate a hydrogen concentrate product flow and a hydrogen depletion tail gas flow; separating the hydrogen depletion tail gas flow by selective permeation to generate a hydrogen concentrate permeate flow and a hydrogen depletion residual flow; and burning a fuel gas to supply heat to the reaction of the reformer feed stream, wherein the fuel gas comprises at least a portion of the hydrogen concentrate permeate flow.

[0009] Embodiment 3: A process for generating a hydrogen concentration product flow, the process comprising: reacting a reformer feed stream, comprising a hydrocarbon feestock and reactants selected from the group consisting of water and carbon dioxide, in the presence of a reforming catalyst to generate a synthesis gas flow containing hydrogen, carbon monoxide, and carbon dioxide; reacting the synthesis gas flow or a flow derived from the synthesis gas flow in the presence of a first shift catalyst to generate a shifted synthesis gas flow; reacting the shifted synthesis gas flow in the presence of a second shift catalyst to generate a further shifted synthesis gas flow; separating the further shifted synthesis gas flow to generate a carbon dioxide concentration flow and a carbon dioxide depletion flow; separating the carbon dioxide depletion flow to generate a hydrogen concentration product flow and a hydrogen depletion tail gas flow; separating the hydrogen depletion tail gas flow by selective permeation to generate a hydrogen concentration permeate flow and a hydrogen depletion residual flow; and burning a fuel gas to supply heat to the reaction of the reformer feed stream, wherein the fuel gas comprises at least a portion of the hydrogen concentration permeate flow.

[0010] Embodiment 4: A process for generating a hydrogen concentration product stream, wherein the process comprises a hydrocarbon raw material (hydrocarbon A process comprising: reacting a reformer feedstream containing a reactant selected from the group consisting of (feestock), water, and carbon dioxide, in the presence of a reforming catalyst to produce a synthesis gas flow containing hydrogen, carbon monoxide, and carbon dioxide; partially oxidizing and reacting the synthesis gas flow with an oxygen-rich gas in the presence of a secondary reforming catalyst to produce a reacted synthesis gas flow; reacting the reacted synthesis gas flow in the presence of a first shift catalyst to produce a shifted synthesis gas flow; reacting the shifted synthesis gas flow in the presence of a second shift catalyst to produce a further shifted synthesis gas flow; separating the further shifted synthesis gas flow to produce a carbon dioxide concentrated flow and a carbon dioxide depleted flow; separating the carbon dioxide depleted flow to produce a hydrogen concentrated product flow and a hydrogen depleted tail gas flow; separating the hydrogen depleted tail gas flow by selective permeation to produce a hydrogen concentrated permeate flow and a hydrogen depleted residual flow; and burning a fuel gas to supply heat to the reaction of the reformer feedstream, wherein the fuel gas contains at least a portion of the hydrogen concentrated permeate flow.

[0011] Embodiment 5: A process for generating a hydrogen concentration product stream, the process comprising: reacting a reformer feed stream, comprising a hydrocarbon feestock and reactants selected from the group consisting of water and carbon dioxide, in the presence of a reforming catalyst to generate a synthesis gas stream containing hydrogen, carbon monoxide, and carbon dioxide; combining an oxygen-rich gas with the synthesis gas stream in the presence of a secondary reforming catalyst to partially oxidize and react the synthesis gas stream to generate a reacted synthesis gas stream; reacting the reacted synthesis gas stream in the presence of a first shift catalyst to generate a shifted synthesis gas stream; separating the shifted synthesis gas stream to generate a carbon dioxide concentration stream and a carbon dioxide depletion stream; separating the carbon dioxide depletion stream to generate a hydrogen concentration product stream and a hydrogen depletion tail gas stream; separating the hydrogen depletion tail gas stream by selective permeation to generate a hydrogen concentration permeate stream and a hydrogen depletion residual stream; and burning a fuel gas to supply heat to the reaction of the reformer feed stream, wherein the fuel gas comprises at least a portion of the hydrogen concentration permeate stream.

[0012] Embodiment 6: A process for generating a hydrogen concentration product stream, the process comprising: reacting a reformer feed stream, comprising a hydrocarbon feestock and reactants selected from the group consisting of water and carbon dioxide, in the presence of a reforming catalyst to generate a synthesis gas stream containing hydrogen, carbon monoxide, and carbon dioxide; combining an oxygen-rich gas with the synthesis gas stream in the presence of a secondary reforming catalyst to partially oxidize and react the synthesis gas stream to generate a reacted synthesis gas stream; separating the reacted synthesis gas stream to generate a carbon dioxide concentration stream and a carbon dioxide depletion stream; separating the carbon dioxide depletion stream to generate a hydrogen concentration product stream and a hydrogen depletion tail gas stream; separating the hydrogen depletion tail gas stream by selective permeation to generate a hydrogen concentration permeate stream and a hydrogen depletion residual stream; and burning a fuel gas to supply heat to the reaction of the reformer feed stream, wherein the fuel gas comprises at least a portion of the hydrogen concentration permeate stream.

[0013] Embodiment 7: The process according to Embodiment 3 or 4, wherein the temperature of the synthesis gas flow is higher than the temperature of the shifted synthesis gas flow.

[0014] Embodiment 8: The process according to any one of Embodiments 1 to 7, wherein the reaction of the reformer feed stream is carried out in a plurality of catalyst-containing reformer tubes.

[0015] Embodiment 9: The process according to any one of Embodiments 1 to 8, further comprising combining at least a portion of the hydrogen depletion residue logistics with the reformer supply flow.

[0016] Embodiment 10: The process according to any one of Embodiments 4 to 6, further comprising pre-combining at least a portion of the hydrogen depletion residual logistics with the reacted synthesis gas flow.

[0017] Embodiment 11: The process according to any one of embodiments 1 to 10, further comprising reacting a pre-reformer feed stream containing methane and a reactant selected from the group consisting of water and carbon dioxide in the presence of a pre-reformer catalyst to produce a reformer feed stream.

[0018] Embodiment 12: The process according to Embodiment 11, further comprising aligning at least a portion of the hydrogen depletion residual logistics with the pre-reformer supply flow.

[0019] Embodiment 13: The process according to any one of embodiments 1 to 12, further comprising separating the hydrogen-depleted tail gas flow by selective permeation, generating a second hydrogen-concentrated permeation flow, and combining the second hydrogen-concentrated permeation flow with the hydrogen-depleted tail gas flow.

[0020] Embodiment 14: The process according to any one of Embodiments 1 to 13, further comprising splitting at least a portion of the hydrogen depletion tail gas flow to form a tail gas fuel fraction, wherein the fuel gas comprises the tail gas fuel fraction.

[0021] Embodiment 15: Apparatus for generating a hydrogen enrichment product flow, wherein the apparatus comprises a reformer including a reforming catalyst and one or more burners, the reformer configured to receive a reformer feed flow containing methane and reactants selected from the group consisting of water and carbon dioxide, and to contact the reforming catalyst to generate a synthesis gas flow containing hydrogen, carbon monoxide, and carbon dioxide, and one or more burners configured to burn a fuel gas in the presence of the reforming catalyst and transfer thermal energy to the reformer feed flow, and a carbon dioxide removal system configured to receive the synthesis gas flow or a flow derived from the synthesis gas flow to generate a carbon dioxide enrichment flow and a carbon dioxide depletion flow. An apparatus comprising: a product purification system having an inlet port, a product outlet port, and a tail gas outlet port configured to receive a carbon dioxide depletion flow and generate a hydrogen depletion tail gas flow and a hydrogen concentration product flow; a membrane separation system having an inlet port, a permeate outlet port, and a residue outlet port configured to receive a hydrogen depletion tail gas flow and generate a hydrogen concentration permeate flow and a hydrogen depletion residue flow; a tail gas conduit that is in fluid flow communication with the tail gas outlet of the product purification system and the inlet port of the membrane separation system; and one or more burners and a fuel gas conduit that is in fluid flow communication with the permeate outlet port of the membrane separation system.

[0022] Embodiment 16: The apparatus according to Embodiment 15, further comprising one or more water-gas shift reactors in series downstream of the reformer and upstream of the carbon dioxide removal system.

[0023] Embodiment 17: The apparatus according to Embodiment 15 or Embodiment 16, wherein the reformer comprises a plurality of catalyst-containing reformer tubes.

[0024] Embodiment 18: The apparatus according to any one of Embodiments 15 to 17, wherein the residue outlet port of the membrane separation system is in communication with the reformer supply flow and the fluid flow.

[0025] Aspect 19: The apparatus according to any one of Aspects 15 to 18, further comprising a secondary reformer located downstream of the reformer and upstream of the carbon dioxide removal system, configured to receive a syngas stream in the presence of an oxygen-rich gas, partially oxidize it, and cause a reaction, wherein the secondary reformer contains a secondary reforming catalyst.

[0026] Aspect 20: The apparatus according to Aspect 19, wherein the residue outlet port of the membrane separation system is in fluid communication with the syngas stream upstream of the secondary reformer.

[0027] Aspect 21: The apparatus according to any one of Aspects 15 to 20, further comprising a pre-reformer located upstream of the reformer, configured to receive a pre-reformer feed stream containing methane and a reactant selected from the group consisting of water and carbon dioxide, and generate a reformer feed stream, wherein the pre-reformer contains a pre-reforming catalyst.

[0028] Aspect 22: The apparatus according to Aspect 21, wherein the residue outlet port of the membrane separation system is in fluid communication with the pre-reformer feed stream.

[0029] Aspect 23: The apparatus according to any one of Aspects 15 to 22, wherein the tail gas conduit comprises a tail gas compressor.

[0030] Aspect 24: The apparatus according to any one of Aspects 15 to 23, wherein the membrane separation system comprises a second permeate outlet port, and the second permeate outlet port is in fluid communication with the tail gas conduit.

[0031] Aspect 25: The apparatus according to any one of Aspects 15 to 24, wherein one or more burners are in fluid communication with the tail gas conduit.

Brief Description of the Drawings

[0032] The present disclosure will hereinafter be described in conjunction with the accompanying drawings, where like numerals represent like elements.

[0033] [Figure 1]This figure shows embodiments of a reforming process according to one or more aspects of the present disclosure, in which a portion of the tail gas is compressed and separated in a membrane. The hydrogen-enriched permeate is used as fuel gas, and the hydrogen-depleted residual gas is recycled to the reformer feed. [Figure 2] This figure shows a modification of the embodiment of Figure 1, in which hydrogen depletion residue is recycled into the supply for the pre-reformer. [Figure 3] This figure shows a modification of the embodiment in Figure 1, in which hydrogen depletion residue is recycled into the secondary reformer feed. [Figure 4] This figure shows a modification of the embodiment of Figure 1 in which carbon dioxide is captured using an adsorption system. [Figure 5] This figure shows a modification of the embodiment of Figure 1, in which the second hydrogen-concentrated permeate is removed from the second-stage membrane and recycled into the tail gas. [Figure 6] This figure shows a modification of the embodiment in Figure 1, in which a portion of the reformer feed is supplied to a recuperative reformer and heated by the synthesis gas flow. [Figure 7] This figure shows a modification of the embodiment shown in Figure 6, which is heated by a combination of synthesis gas and the regenerative reformer outlet gas. [Modes for carrying out the invention]

[0034] The following detailed description provides only preferred exemplary embodiments and is not intended to limit the scope, applicability, or configuration of the invention. Rather, the following detailed description of preferred exemplary embodiments will provide a useful explanation for implementing preferred exemplary embodiments of the invention for those skilled in the art. Various modifications can be made to the function and arrangement of the elements without departing from the spirit and scope of the invention, as described in the appended claims.

[0035] As used herein, the articles "a" or "an," when applied to any feature in embodiments of the invention described herein and in the claims, mean one or more. The use of "a" and "an" does not limit the meaning to a single feature unless such limitation is specifically stated. The article "the," preceding a singular or plural noun or noun phrase, indicates a specific designated feature or a particular designated feature, and may have singular or plural implications depending on the context in which it is used.

[0036] The phrase "at least a part" means "a part or all of." "At least a part of the flow" means having the same composition, each having the same concentration of species as the flow from which it originates.

[0037] The term "and / or" placed between a first entity and a second entity includes any of the following meanings: (1) the first entity only, (2) the second entity only, or (3) the first entity and the second entity. The term "and / or" placed between the last two entities in a list of three or more entities means at least one of the entities in the list, including any particular combination of entities in the list. For example, "A, B, and / or C" has the same meaning as "A and / or B and / or C," and includes the following combinations of A, B, and C: (1) A only, (2) B only, (3) C only, (4) A and B but not C, (5) A and C but not B, (6) B and C but not A, and (7) A, B, and C.

[0038] The adjective "any" means one, some, or all of a quantity without distinction.

[0039] The terms "depleted" or "dilute" mean that the indicated component has a lower molar percentage concentration than the original flow in which it was formed. "Depleted" and "dilute" do not mean that the flow is completely lacking in the indicated component.

[0040] The terms "rich" or "concentrated" mean that the indicated component has a higher molar percentage concentration than the original flow into which it was formed.

[0041] "Downstream" and "upstream" refer to the intended flow direction of the transferred process fluid. If the intended flow direction of the process fluid is from the first device to the second device, the second device is downstream of the first device. In the case of recirculation flow, downstream and upstream refer to the initial path of the process fluid.

[0042] The term "indirect heat exchange" refers to the process by which sensible and / or latent heat is transferred between two or more fluids without physical contact between them. Heat can be transferred through the walls of the heat exchanger or using an intermediate heat transfer fluid. The term "heat flow" refers to any flow that leaves the heat exchanger at a lower temperature than it entered. Conversely, a "cold flow" is one that leaves the heat exchanger at a higher temperature than it entered.

[0043] Figure 1 shows an embodiment of reforming process 1 for generating hydrogen and capturing carbon dioxide from a hydrocarbon feedstock. The hydrocarbon feedstock comprises at least one hydrocarbon species having one or more carbon atoms and may be linear, branched, cyclic, or aromatic. The hydrocarbon feedstock may include both saturated and unsaturated hydrocarbon species. The hydrocarbon feedstock may be derived from natural gas, liquefied petroleum gas, refined off-gas, naphtha, and / or other feedstocks known in the art.

[0044] The reformer feed stream 10, containing steam and hydrocarbon feedstock, enters a plurality of catalyst-containing reformer tubes 104 within the reformer furnace 100. In the plurality of catalyst-containing reformer tubes 104, the hydrocarbon feedstock reacts with steam at a temperature in the range of 700°C to 1000°C and a pressure in the range of 2 to 50 atmospheres to form a synthesis gas stream 12 containing hydrogen, carbon monoxide, and carbon dioxide.

[0045] Reformer furnaces having multiple catalyst-containing reformer tubes, i.e., tubular reformers, are well known to those skilled in the art. Suitable materials and construction methods are known. The catalyst in the catalyst-containing reformer tube 104 may be any suitable catalyst or combination of catalysts known in the art, for example, a nickel-supported catalyst.

[0046] In at least some embodiments, the reformer feed stream 10 may be produced by an optional pre-reformer 80, defined as any unignited vessel that converts hydrocarbon feedstock by reacting with vapor on a catalyst, with or without heating. The pre-reformer 80 may be a fixed-bed reactor or a tubular reactor. In at least some embodiments, the pre-reformer may use a different type of catalyst than that used in the catalyst-containing reformer tube 104, for example, a highly active, high-nickel-content catalyst. In the embodiment shown in Figure 1, the pre-reformer feed stream 14, containing vapor and hydrocarbon feedstock, enters the pre-reformer 80. In the presence of the pre-reforming catalyst 84, the hydrocarbon feedstock reacts with vapor at a temperature in the range of 400°C to 600°C and a pressure in the range of 2 to 50 atmospheres to form the reformer feed stream 10. The hydrocarbon feedstock in the pre-reformer feed stream 14 and the reformer feed stream 10 may consist of one or more compositions that may be altered as a result of the reforming reaction in the pre-reformer. For example, propane and butane in the pre-reformer feed stream 14 may react to form methane in the reformer feed stream 10.

[0047] The pre-reforming catalyst 84 may contain at least one metal selected from the group consisting of nickel, cobalt, platinum, palladium, rhodium, ruthenium, iridium, and mixtures thereof. For example, reforming catalysts suitable for pre-reforming, such as those described in U.S. Patent Nos. 4,105,591, 3,882,636, 3,988,425, British Patent No. 969,637, British Patent No. 1,150,066, and British Patent No. 1,155,843, can be used in at least some embodiments.

[0048] The pre-reforming catalyst 84 can exist in a wide variety of shapes or forms, such as cylindrical pellets, Raschig rings, multi-hole catalysts, or other forms known in the art. In at least some exemplary embodiments, the catalyst size may range from about 1 mm to about 15 mm in diameter, and the catalyst length may range from about 3 mm to 10 mm. The preferred size for a given application depends on many factors, including the catalyst shape and nickel load, operating temperature, pressure, and feed composition, as well as the allowable pressure drop. Catalysts having a multi-hole shape with a diameter in the range of 5 mm to 25 mm and a height-to-diameter ratio of 0.5 to 1.2 are also suitable for the pre-reforming catalyst 84. Those skilled in the art can select a suitable catalyst having a suitable shape for the pre-reforming catalyst 84.

[0049] In at least some exemplary embodiments, the rereforming catalyst 84 may also be a structured packing catalyst, where the catalyst is applied as a wash coat on a structured packing. Structured packings are known to those skilled in the art. As used herein, the term “structured packing” means a flow guide having a plurality of substantially parallel passages. Substantially parallel means parallel within manufacturing tolerances. Davidson’s U.S. Patent No. 4,340,501 describes a structure in a reactor vessel that would be suitable for a prereforming catalyst in a structured packing, allowing a fluid to be intermittently but controllably brought into contact with the vessel wall.

[0050] In at least some embodiments, the synthesis gas stream 12 may be further combined with a secondary feed stream 28 and reformed in an optional secondary reformer 20. The secondary reformer 20 may also combine oxygen-rich gas 26 with the synthesis gas stream 12 to partially oxidize the synthesis gas stream 12 and react it in the presence of a secondary reforming catalyst 24 to further convert unreacted hydrocarbon species to produce carbon monoxide and hydrogen, forming a reacted synthesis gas stream 22. In at least some embodiments, the oxygen-rich gas 26 may be combined with the synthesis gas stream 12 before the secondary reformer 20, or it may be combined with the synthesis gas stream 12 in the secondary reformer 20, for example, by a burner.

[0051] The secondary feed stream 28 may be introduced into the synthesis gas stream 12 before the resulting mixture is introduced into the secondary reformer reactor 20. The feed gas 28 may also be introduced into the synthesis gas stream 12 in the secondary reformer reactor 20. In most embodiments, oxygen-rich gas will be introduced into the secondary reformer reactor 20 separately from the secondary feed stream 28 and the synthesis gas stream 12. The hydrocarbon source for the secondary feed stream 28 may be the same as the hydrocarbon source for the reformer feed stream 10 and / or the pre-reformer feed stream 14.

[0052] By providing a feed gas containing at least one hydrocarbon and reacting the feed gas in the secondary reforming reactor 20, it becomes possible to reform additional hydrocarbon feedstocks without increasing the size of the reformer furnace 100 and, accordingly, the size of the multiple catalyst-containing reformer tubes. Those skilled in the art can suitably optimize the size and amount of feedstocks processed in the reformer furnace 100 and the secondary reforming reactor 20. Another advantage provided by the secondary reforming reactor 20 is the reduction of fuel requirements in the reformer furnace 100.

[0053] Secondary reformers are well known in the art and are widely used for the production of ammonia and methanol. A secondary reformer is a refractory-lined vessel equipped with one or more burners and a reforming catalyst bed. The heat required for the reforming reaction may be provided by the partial oxidation (combustion) of a portion of the feed. Effluent from a primary reformer may be supplied to a secondary reformer to be mixed with oxygen supplied through a burner. The partial oxidation reaction takes place in a reaction zone adjacent to or immediately below the burner. The partially oxidized mixture then passes through a catalyst bed to which the mixture is substantially thermodynamically equilibrated on the reforming catalyst. U.S. Patent No. 3,479,298, incorporated herein by reference, discloses a secondary reformer for the production of hydrogen-containing gases, and discloses that when oxygen is used instead of air, the process gas emanating from the secondary reformer is a gas suitable for further treatment to obtain methanol or high-purity hydrogen. Tindall et al., “Alternative technologies to steam-methane reforming,” Hydrocarbon Processing, pp. 75-82, November, 1995 also discloses an oxygen secondary reformer for generating hydrogen.

[0054] In at least some embodiments of the present disclosure, the reacted synthesis gas flow 22 is cooled in a heat exchanger system 30 comprising a boiler for generating steam 36 from a water-containing flow 34 by indirect heat exchange with the reacted synthesis gas flow 22. The cooled synthesis gas flow 32 is generated by the heat exchanger system 30. The heat exchanger system 30 may also utilize the heat from the reacted synthesis gas flow 22 to provide heating obligations required by the SMR process to improve overall thermal efficiency, such as preheating the reformer feed flow 10.

[0055] Using the first water-gas shift reactor 40, carbon monoxide in a cooled synthesis gas stream 32 can be reacted with water in the presence of a shift catalyst 44 to produce a shifted synthesis gas stream 42 containing more hydrogen. The cooled synthesis gas stream 32 enters at a first temperature, and in exemplary embodiments where the first water-gas shift reactor 40 is an adiabatic reactor, the temperature of the cooled synthesis gas stream 32 rises for the heat-dissipating shift reaction. If the first water-gas shift reactor 40 is cooled, the cooled synthesis gas stream 32 may remain at a constant temperature or may be cooled overall. To enhance the water-gas shift (WGS) reaction, a first additional steam 46 can be optionally introduced into the reactor to shift the equilibrium to more hydrogen and carbon dioxide. The WGS catalyst may be an iron-based high-temperature WGS catalyst, a copper-based medium-temperature WGS catalyst, a copper-based low-temperature WGS catalyst, or any other suitable WGS catalyst, as can be selected by those skilled in the art. The first shift catalyst 44 may contain iron oxide, and the reaction temperature may be 310°C to 500°C or 310°C to 400°C. The first shift catalyst 44 may contain copper, and the reaction temperature may be 200°C to 400°C or 200°C to 350°C. In at least some exemplary embodiments, the shifted synthesis gas stream 42 may enter a second water-gas shift reactor 50 equipped with a second shift catalyst 54 at a second temperature to produce a further shifted synthesis gas stream 52. A second additional vapor (not shown) may optionally be introduced into the second water-gas shift reactor 50. The second temperature may be lower than the first temperature to allow the shifted synthesis gas stream 42 to react more carbon monoxide with water to produce hydrogen as the equilibrium shifts toward hydrogen at a lower temperature. The second shift catalyst 54 may contain copper and / or zinc oxide, and the reaction temperature may be in the range of 190°C to 300°C. The second temperature may also be the same as the first temperature, or higher than the first temperature, when the temperature of the cooled synthesis gas stream 32 rises in the first water-gas shift reactor 40, and the shifted synthesis gas stream 42 may then be cooled before entering the second water-gas shift reactor 50.

[0056] Carbon dioxide is removed from the further shifted synthesis gas flow 52 in the carbon dioxide removal system 60. The carbon dioxide removal system 60 may include a gas scrubber in which a wash flow 64 comes into contact with the further shifted synthesis gas flow 52 to produce a carbon dioxide depleted synthesis gas flow 62 and a carbon dioxide concentrated wash flow 66. The wash flow 64 may be any scrubbing fluid known in the art, such as N-methyldiethanolamine (aMDEA), monoethanolamine (MEA), other amine systems, or other scrubbing methods, such as Rectisol®, Selexol®, Genosorb®, and other scrubbing fluids related to sulfinol.

[0057] The carbon dioxide-depleted synthesis gas stream 62 is supplied to the inlet port of the product purification unit 70, producing a hydrogen-concentrated product stream 72 that exits through the product outlet port and a hydrogen-depleted tail gas stream 76 containing hydrogen, methane, and carbon monoxide that exits through the tail gas outlet port. This product purification unit may also be a pressure fluctuation absorption unit for the hydrogen production process. In at least some embodiments, at least a portion of the tail gas stream 76 may be compressed in a tail gas compressor 75 to produce a compressed tail gas stream 78.

[0058] The compressed tail gas stream 78 enters the inlet port of a membrane separation system 90, which may have a single membrane stage or multiple membrane stages in series and / or parallel. The compressed tail gas stream 78 is separated by selective permeation into a hydrogen-concentrated permeation stream 92 exiting through a permeate outlet port and a hydrogen-depleted residual stream 94 exiting through a residual outlet port. Hydrogen permeates the membrane more selectively than slower species such as methane and carbon monoxide. Due to the small size of the hydrogen molecule, it has a high diffusivity and is therefore expected to permeate faster than methane and carbon monoxide in most membrane materials.

[0059] Sanders et al (Polymer; vol 54; pp4729-4761; 2013) provide a convenient summary of current membrane technologies. They describe the physical parameters and performance characteristics of polymer membranes, including polystyrene, polysulfone, polyethersulfone, polyvinyl fluoride, polyvinylidene fluoride, polyetheretherketone, polycarbonate, polyphenylene oxide, polyethylene, polypropylene, cellulose acetate, polyimide (such as Matrimid 5218 or P-84), polyamide, polyvinyl alcohol, polyvinyl acetate, polyethylene oxide, polydimethylsiloxane, copolymers, block copolymers, or polymer blends. Existing industrially useful gas separations are mainly performed with polymers such as those listed above, or rubbery materials such as silicone. Additional membrane materials may include mixed matrix membranes, perfluoropolymers, thermally rearranged polymers, facilitated transport membranes, metal-organic frameworks, zeolite-imidazolate frameworks, electrochemical membranes, metal membranes, and carbon molecular sieves. The membrane material in the membrane separation system 90 may be any of those listed above, or any other material having a faster permeation rate for some compounds such as hydrogen and a slower permeation rate for some compounds such as methane and carbon monoxide. In exemplary embodiments where the membrane material includes a metal highly selective for hydrogen, such as palladium, the membrane separation system 90 would operate at high temperatures such as 280–440°C.

[0060] Suitable membrane materials may be manufactured as hollow fibers and packaged as membrane bundles, or, to provide a larger surface area-to-volume ratio, they may be manufactured as flat sheets and packaged as spiral windings or plate-frame units and housed in modules. Gases entering the module come into contact with the membrane, small amounts of gas permeate through the membrane, and exit the module via low-pressure permeation flow. Faster permeable gases are concentrated in the permeate compared to slower permeable gases. Small amounts of gas that do not permeate the membrane exit the module via impermeable flow, or residual flow, which is concentrated with slower permeable gases compared to faster permeable gases.

[0061] In at least some exemplary embodiments, if any compounds that impair the operation of the membrane, such as heavy hydrocarbons (hexane and heavy alkanes) and / or aromatic compounds such as benzene, toluene, and xylene (collectively known as BTX), are present, the compressed tail gas stream 78 may be treated before being introduced into the membrane separation system 90. Pretreatment can be carried out by adsorption, absorption, or partial condensation. In at least some embodiments, pretreatment would be unnecessary because the reforming reaction in the upstream catalyst-containing reformer tube 104 is expected to consume any hazardous compounds.

[0062] At least a portion of the hydrogen enrichment permeate flow 92 is burned as fuel gas 74 in one or more burners 102 to supply heat to the reformer furnace 100 to drive the endothermic reforming reaction in the catalyst-containing reformer tubes 104. The fuel gas 74 may also include a tail gas fuel fraction 77 formed by splitting a portion of the hydrogen depletion tail gas flow 76. In at least some embodiments, the tail gas fuel fraction 77 may also function as a purge flow to allow slow-permeable inert components, such as nitrogen and / or argon, rejected by the membrane separation system 90, to exit the system. Since the slow-permeable inert components are not consumed in the reforming reaction, the main route for them to exit the process is through one or more burners 102. In at least some embodiments, the fuel gas 74 may also include a hydrogen product fuel fraction 73 formed by splitting a portion of the hydrogen enrichment product flow 72 and / or auxiliary fuel 18. The flue gas 110 exiting the reformer furnace 100 may provide the heating obligation required by the SMR process to improve overall thermal efficiency, such as preheating the reformer feed stream 10. According to at least some embodiments of this disclosure, the flue gas 110 of the disclosed process and apparatus has a reduced amount of carbon dioxide compared to existing processes in which a hydrogen-depleted tail gas stream 76 can be burned within the reformer furnace 100. In at least some exemplary embodiments, reducing the flow rate of the tail gas fuel fraction 77 increases the overall carbon capture rate as fewer carbon-containing species exit through the flue gas 110, but the load on the product purification unit 70 increases as more inert gas is supplied to it. This presents a trade-off in which a higher carbon capture percentage requires a higher load on the product purification unit 70.

[0063] The hydrogen depletion residual flow 94 is recirculated into the steam methane reforming process by being combined with the reformer feed flow 10. In at least some embodiments, the hydrogen depletion residual flow 94 may first be heated by one or more high-temperature flows, such as the reacted synthesis gas flow 22, flue gas 110, and steam. According to at least some embodiments of the present disclosure, by recirculating the hydrogen depletion residual flow 94, methane and additional carbon-containing compounds such as carbon monoxide in the residual flow 94 can be converted to carbon dioxide and captured by the carbon dioxide removal system 60, which can reduce the amount of carbon dioxide emitted from the reforming process. The amount of carbon dioxide emitted in the flue gas 110 can be adjusted by changing the amount of hydrogen product fuel fraction 73, the amount of tail gas fuel fraction 77, and the amount of auxiliary fuel 18 used as fuel.

[0064] In at least some embodiments, where the majority of carbon-containing compounds in the tail gas 76 are separated into hydrogen depletion residue flow 94 in a membrane separation system 90 and recycled to a reforming process, and the fuel gas 74 mainly consists of hydrogen product fuel fraction 73 and hydrogen concentrated permeate flow 92, carbon dioxide emissions in the flue gas 110 can be substantially reduced compared to existing processes. In at least some embodiments, the tail gas fuel fraction 77 can be used as fuel gas 74 to reduce the accumulation of inert gases (e.g., nitrogen and argon) in the process flow. In some embodiments of the present disclosure, a portion of the tail gas 76 may be used in another process and / or discarded, for example, a portion of the compressed residue may be sent to another process located close to the hydrogen plant, for example, as fuel for an ignited heater or boiler.

[0065] The hydrogen depletion residue flow 94 can typically be recycled to another location upstream of the reformer. Figure 2 shows an alternative embodiment of Figure 1 in which the hydrogen depletion residue flow 94 is combined with the pre-reformer feed flow 14. Figure 3 shows an alternative embodiment of Figure 1 in which the hydrogen depletion residue flow 94 is combined with the synthesis gas flow 12 upstream of the secondary reformer 20. In at least some embodiments, the hydrogen depletion residue flow 94 may be combined with a cooled synthesis gas flow 32 upstream of the first water-gas shift reactor 40, or with a shifted synthesis gas flow 42 (not shown) upstream of the second water-gas shift reactor 50.

[0066] The flow sheet shown in Figure 4 illustrates an embodiment of reforming process 4 according to an additional exemplary embodiment of the present disclosure, wherein the carbon dioxide removal system 60 comprises an adsorption system such as a vacuum swing adsorption system. Hsu et al. (US8,709,136) teach one such adsorption system that can be used to remove carbon dioxide from a synthesis gas stream. The carbon dioxide-enriched blowdown gas 166 may be low pressure or under vacuum. In at least some embodiments, an optional rinse stream 164 may be used to improve recovery.

[0067] The flow sheet shown in Figure 5 illustrates an embodiment of reforming process 5 according to an additional exemplary embodiment of the present disclosure, wherein the membrane separation system comprises two stages: a first stage 90A and a second stage 90B. The hydrogen depletion residue flow 94 enters the inlet port of the second stage 90B. The second hydrogen depletion residue flow 594 exits through the second residue outlet port and is joined with the reformer feed flow 10. The second hydrogen concentrated permeate flow 592 may exit through the second permeate flow outlet and be joined with the hydrogen depletion tail gas flow 76 upstream of the tail gas compressor 75. According to at least some embodiments of the present disclosure, using two stages of membrane separation can reduce the amount of hydrogen recirculated into the reformer feed flow 100 and improve the overall efficiency of the reforming process. The tail gas compressor 75 provides an efficient point for recirculating the low-pressure flow exiting the membrane separation system without the cost of an additional compressor.

[0068] According to at least some embodiments of this disclosure, carbon dioxide capture can be enhanced by injecting more carbon dioxide into the process into any of the pre-reformer feedstream 14, reformer feedstream 10, synthesis gas stream 12, secondary feedstream 28, and / or hydrogen depletion residual stream 94. In some embodiments, carbon dioxide can partially or completely replace steam in the reforming reaction. Carbon dioxide acts as a reactant with hydrocarbon feedstocks, just as steam is a reactant with hydrocarbon feedstocks in steam reforming. Substantially, dry reforming can be considered stoichiometrically equivalent to a combination of steam reforming and reverse WGS reaction, as shown below.

[0069] CO2 + CH4 = 2H2 + 2CO (drying and reforming)

[0070] H2O + CH4 = 3H2 + CO (steam reforming)

[0071] CO2 + H2 = CO + H2O (inverse WGS)

[0072] The flow sheet shown in Figure 6 illustrates an embodiment of reforming process 6 according to an additional exemplary embodiment of the present disclosure, in which a portion of the reformer feed flow 10 is split to form a regenerative reformer feed flow 614, which is supplied to the regenerative reformer 680. The regenerative reformer is a heat exchanger that transfers heat to drive the catalytic reforming reaction. This makes it possible to use more process heat to drive more reforming reactions, which is particularly relevant to applications requiring low or zero export steam. In at least some embodiments, steam (not shown) may be added to the regenerative reformer feed flow 614 upstream of the regenerative reformer 680. The regenerative reformer 680 may be implemented in a shell and tubular arrangement. In the exemplary embodiment shown in Figure 6, the regenerative reformer feed flow 614 enters the tubular side 684 containing the regenerative reforming catalyst of the regenerative reformer 680. The synthesis gas flow 12 enters the shell side and provides heat to the regenerative reformer feed flow 614, which reacts in the presence of the regenerative reforming catalyst to form the regenerative reformer outlet flow 682. The regenerative reformer outlet flow 682 is combined with the cooled synthesis gas flow 686 and optionally supplied to the secondary reformer 20, as in reforming process 1. In at least some embodiments, at least a portion of the hydrogen depletion residual flow 94 may be combined with the regenerative reformer feed flow 614 (not shown).

[0073] The flowsheet diagram shown in Figure 7 illustrates an embodiment of reforming process 7 according to an additional exemplary embodiment of the present disclosure, in which the regenerative reformer outlet flow 682 is combined with the synthesis gas flow 12 before entering the high-temperature side of the regenerative reformer 680. The piping of the regenerative reformer may be simplified according to the exemplary embodiment shown, for example, the mixing point of the regenerative reformer outlet flow 682 and the synthesis gas flow 12 may occur within the regenerative reformer 680. In at least some embodiments, at least a portion of the hydrogen depletion residue flow 94 may be combined with the regenerative reformer feed flow 614 (not shown). [Examples]

[0074] While the principles of this disclosure are described above in relation to preferred embodiments, it should be clearly understood that this description is provided for illustrative purposes only and does not limit the scope of this disclosure.

[0075] The embodiment of reforming process 1 in Figure 1, using a single-stage membrane, was analyzed using commercially available Aspen® process modeling software and compared to a modification of Figure 1 in which the membrane separation system 90 is eliminated and the compressed tail gas flow 78 is directly matched with the reformer feed flow 10. For both processes, 100,000 Nm3 / hr (9000 kg / hr) of hydrogen is produced, and 96% of the carbon dioxide produced in the overall process is captured. Table 1 compares the performance of reforming process 1 with and without the membrane, with and without utility consumption and performance parameters. The export steam is sent to the battery limit at 750°F and 625 psia. Degradation is defined as the reduction in hydrogen production normalized to the same natural gas input compared to a process without carbon dioxide capture. The reduction in hydrogen production is substantially equal to the amount of hydrogen product that must be burned in the burner as the hydrogen product fuel fraction 73.

[0076] As can be seen in Table 1, the reduction rate of the membrane-based reforming process 1 is lower when using the membrane separation system 90 than when not using a membrane, indicating that less product hydrogen must be burned in the reactor. Correspondingly, the total natural gas consumption of reforming process 1 is lower even with a membrane. The membrane-based reforming process 1 has higher tail gas compressor power consumption, mainly due to the larger recirculation loop causing a higher flow rate of tail gas into the compressor. The energy cost (defined as the net energy consumed in the process minus the heat value of the exported steam divided by the hydrogen production rate) is lower in the case of reforming process 1 with a membrane. The lower export steam flow rate indicates that the membrane separation system 90 is more efficient in converting natural gas to hydrogen, resulting in less waste heat being converted into steam. [Table 1] Examples of embodiments of the present invention are listed below. [Aspect 1] A process for generating a hydrogen concentration product stream, wherein the process is A reformer feed stream containing a hydrocarbon feedstock and a reactant selected from the group consisting of water and carbon dioxide is reacted in the presence of a reforming catalyst to produce a synthesis gas stream containing hydrogen, carbon monoxide, and carbon dioxide. The synthesis gas flow or a flow derived from the synthesis gas flow is separated to generate a carbon dioxide concentration flow and a carbon dioxide depletion flow, The carbon dioxide depletion flow is separated to generate the hydrogen enrichment product flow and the hydrogen depletion tail gas flow, By selective permeation, the hydrogen-depleted tail gas flow is separated to generate hydrogen-concentrated permeated flow and hydrogen-depleted residual flow, This includes burning fuel gas to supply heat to the reaction in the reformer feed stream, A process wherein the fuel gas includes at least a portion of the hydrogen-concentrated permeation logistics. [Aspect 2] The method further includes reacting the synthesis gas flow or a flow derived from the synthesis gas flow in the presence of a first shift catalyst to generate a synthesis gas flow that has been shifted before separation, thereby generating a carbon dioxide enrichment flow and a carbon dioxide depletion flow. The process according to embodiment 1, wherein the synthesis gas flow or the flow derived from the synthesis gas flow has a first temperature. [Aspect 3] The shifted synthesis gas flow is reacted in the presence of a second shift catalyst to generate a further shifted synthesis gas flow before separation, thereby generating a carbon dioxide enrichment flow and a carbon dioxide depletion flow. The process according to embodiment 2, wherein the shifted synthesis gas flow has a second temperature. [Aspect 4] The process according to embodiment 3, wherein the first temperature is greater than the second temperature. [Aspect 5] The process according to embodiment 1, wherein the reaction in the reformer feed stream is carried out in a plurality of catalyst-containing reformer tubes. [Aspect 6] The process according to embodiment 1, further comprising combining at least a portion of the hydrogen depletion residual logistics with the reformer supply flow. [Aspect 7] The process according to embodiment 1, further comprising combining an oxygen-rich gas with the synthesis gas stream in the presence of a secondary reforming catalyst, and reacting the synthesis gas stream to partially oxidize it before separation, thereby generating a carbon dioxide-rich stream and a carbon dioxide-depleted stream. [Aspect 8] The process according to embodiment 7, further comprising combining at least a portion of the hydrogen-depleted residual flow with the synthesis gas flow before combining it with the oxygen-rich gas in the presence of the secondary reforming catalyst. [Aspect 9] The process according to embodiment 1, further comprising reacting a pre-reformer feed stream, which includes methane and a reactant selected from the group consisting of water and carbon dioxide, in the presence of a pre-reformer catalyst to generate the reformer feed stream. [Aspect 10] The process according to embodiment 9, further comprising combining at least a portion of the hydrogen depletion residual logistics with the pre-reformer supply flow. [Aspect 11] The process according to embodiment 1, further comprising compressing the hydrogen-depleted tail gas stream before separation by selective permeation. [Aspect 12] The separation of the hydrogen-depleted tail gas flow by selective permeation also generates a second hydrogen-concentrated permeation flow. The process according to embodiment 1, further comprising combining the second hydrogen-concentrated permeation flow with the hydrogen-depleted tail gas flow. [Aspect 13] The method further includes dividing at least a portion of the hydrogen-depleted tail gas flow to form a tail gas fuel fraction. The process according to embodiment 1, wherein the fuel gas includes the tail gas fuel fraction. [Aspect 14] An apparatus for generating a hydrogen concentration product stream, wherein the apparatus is A reformer comprising a reforming catalyst and one or more burners, wherein the reformer is configured to receive a reformer feed stream comprising methane and a reactant selected from the group consisting of water and carbon dioxide, and to bring it into contact with the reforming catalyst to produce a synthesis gas stream comprising hydrogen, carbon monoxide, and carbon dioxide. A reformer comprising one or more burners configured to burn a fuel gas in the presence of the reforming catalyst and transfer thermal energy to the reformer feed stream, A carbon dioxide removal system configured to receive the synthesis gas flow or a flow originating from the synthesis gas flow and generate a carbon dioxide concentration flow and a carbon dioxide depletion flow, A product purification system comprising an inlet port, a product outlet port, and a tail gas outlet port, configured to receive the carbon dioxide depletion flow and generate a hydrogen depletion tail gas flow and a hydrogen enrichment product flow, A membrane separation system comprising an inlet port, a permeate outlet port, and a residue outlet port, configured to receive the hydrogen-depleted tail gas flow and generate hydrogen-concentrated permeate flow and hydrogen-depleted residual flow, A tail gas conduit that is in fluid flow communication with the tail gas outlet of the product purification system and the inlet port of the membrane separation system, An apparatus comprising one or more burners and a fuel gas conduit that is in fluid flow communication with the permeate outlet port of the membrane separation system. [Aspect 15] The apparatus according to embodiment 14, further comprising one or more water-gas shift reactors in series downstream of the reformer and upstream of the carbon dioxide removal system. [Aspect 16] The apparatus according to embodiment 14, wherein the reformer comprises a plurality of catalyst-containing reformer tubes. [Aspect 17] The apparatus according to embodiment 14, wherein the residue outlet port of the membrane separation system is in fluid flow communication with the reformer supply flow. [Aspect 18] The system further comprises a secondary reformer located downstream of the reformer and upstream of the carbon dioxide removal system, configured to receive the synthesis gas flow in the presence of oxygen-rich gas, partially oxidize it, and react it. The apparatus according to embodiment 14, wherein the secondary reformer includes a secondary reforming catalyst. [Aspect 19] The apparatus according to embodiment 18, wherein the residue outlet port of the membrane separation system is in fluid flow communication with the synthesis gas flow upstream of the secondary reformer. [Aspect 20] The system further comprises a pre-reformer located upstream of the reformer, configured to receive a pre-reformer feed stream containing methane and reactants selected from the group consisting of water and carbon dioxide, and to generate the reformer feed stream, The apparatus according to embodiment 14, wherein the pre-reformer includes a pre-reform catalyst. [Aspect 21] The apparatus according to embodiment 20, wherein the residue outlet port of the membrane separation system is in fluid flow communication with the pre-reformer supply flow. [Aspect 22] The apparatus according to embodiment 14, wherein the tail gas conduit is equipped with a tail gas compressor. [Aspect 23] The membrane separation system is equipped with a second permeate outlet port, The apparatus according to embodiment 14, wherein the second permeate outlet port is in fluid flow communication with the tail gas conduit. [Aspect 24] The apparatus according to embodiment 14, wherein one or more burners are in fluid flow communication with the tail gas conduit.

Claims

1. A process for generating a hydrogen concentration product stream, wherein the process is The process involves reacting a reformer feed stream containing hydrocarbon feedstock and a reactant selected from the group consisting of water and carbon dioxide, in the presence of a reforming catalyst, to produce a synthesis gas stream containing hydrogen, carbon monoxide, and carbon dioxide. The synthesis gas flow or a flow derived from the synthesis gas flow is separated to generate a carbon dioxide concentration flow and a carbon dioxide depletion flow, The carbon dioxide depletion flow is separated to generate the hydrogen enrichment product flow and the hydrogen depletion tail gas flow, By selective permeation, the hydrogen-depleted tail gas flow is separated to generate hydrogen-concentrated permeated flow and hydrogen-depleted residual flow, This includes burning fuel gas to supply heat to the reaction in the reformer feed stream, The fuel gas includes at least a portion of the hydrogen concentrated permeate flow, The separation of the hydrogen-depleted tail gas flow by selective permeation also generates a second hydrogen-concentrated permeation flow. A process further comprising combining the second hydrogen-concentrated permeation flow with the hydrogen-depleted tail gas flow.

2. The method further includes reacting the synthesis gas flow or a flow derived from the synthesis gas flow in the presence of a first shift catalyst to generate a synthesis gas flow that has been shifted before separation, thereby generating a carbon dioxide enrichment flow and a carbon dioxide depletion flow. The process according to claim 1, wherein the synthesis gas flow or the flow derived from the synthesis gas flow has a first temperature.

3. The shifted synthesis gas flow is reacted in the presence of a second shift catalyst to generate a further shifted synthesis gas flow before separation, thereby generating a carbon dioxide enrichment flow and a carbon dioxide depletion flow. The process according to claim 2, wherein the shifted synthesis gas flow has a second temperature.

4. The process according to claim 3, wherein the first temperature is greater than the second temperature.

5. The process according to claim 1, wherein the reaction in the reformer feed stream is carried out in a plurality of catalyst-containing reformer tubes.

6. The process according to claim 1, further comprising combining at least a portion of the hydrogen depletion residual logistics with the reformer supply flow.

7. The process according to claim 1, further comprising combining an oxygen-rich gas with the synthesis gas stream in the presence of a secondary reforming catalyst, and reacting the synthesis gas stream to partially oxidize it before separation, thereby generating a carbon dioxide-rich stream and a carbon dioxide-depleted stream.

8. The process according to claim 7, further comprising combining at least a portion of the hydrogen-depleted residual flow with the synthesis gas flow before combining it with the oxygen-rich gas, in the presence of the secondary reforming catalyst.

9. The process according to claim 1, further comprising reacting a pre-reformer feed stream, which includes methane and a reactant selected from the group consisting of water and carbon dioxide, in the presence of a pre-reformer catalyst to generate the reformer feed stream.

10. The process according to claim 9, further comprising combining at least a portion of the hydrogen depletion residual logistics with the pre-reformer supply flow.

11. The process according to claim 1, further comprising compressing the hydrogen-depleted tail gas stream before separation by selective permeation.

12. The method further includes dividing at least a portion of the hydrogen-depleted tail gas flow to form a tail gas fuel fraction. The process according to claim 1, wherein the fuel gas includes the tail gas fuel fraction.

13. An apparatus for generating a hydrogen concentration product stream, wherein the apparatus is A reformer comprising a reforming catalyst and one or more burners, wherein the reformer is configured to receive a reformer feed stream comprising methane and reactants selected from the group consisting of water and carbon dioxide, and to bring it into contact with the reforming catalyst to produce a synthesis gas stream comprising hydrogen, carbon monoxide, and carbon dioxide. A reformer comprising one or more burners configured to burn a fuel gas in the presence of the reforming catalyst and transfer thermal energy to the reformer supply flow, A carbon dioxide removal system configured to receive the synthesis gas flow or a flow originating from the synthesis gas flow and generate a carbon dioxide concentration flow and a carbon dioxide depletion flow, A product purification system comprising an inlet port, a product outlet port, and a tail gas outlet port, configured to receive the carbon dioxide depletion flow and generate a hydrogen depletion tail gas flow and a hydrogen enrichment product flow, A membrane separation system comprising an inlet port, a permeate outlet port, and a residue outlet port, configured to receive the hydrogen-depleted tail gas flow and generate hydrogen-concentrated permeate flow and hydrogen-depleted residual flow, A tail gas conduit that is in fluid flow communication with the tail gas outlet of the product purification system and the inlet port of the membrane separation system, The system comprises one or more burners and a fuel gas conduit that is in fluid flow communication with the permeate outlet port of the membrane separation system, The membrane separation system is equipped with a second permeate outlet port, The apparatus wherein the second permeate outlet port is in fluid flow communication with the tail gas conduit.

14. The apparatus according to claim 13, further comprising one or more water-gas shift reactors in series downstream of the reformer and upstream of the carbon dioxide removal system.

15. The apparatus according to claim 13, wherein the reformer comprises a plurality of catalyst-containing reformer tubes.

16. The apparatus according to claim 13, wherein the residue outlet port of the membrane separation system is in fluid flow communication with the reformer supply flow.

17. The system further comprises a secondary reformer located downstream of the reformer and upstream of the carbon dioxide removal system, configured to receive the synthesis gas flow in the presence of oxygen-rich gas, partially oxidize it, and react it. The apparatus according to claim 13, wherein the secondary reformer includes a secondary reforming catalyst.

18. The apparatus according to claim 17, wherein the residue outlet port of the membrane separation system is in fluid flow communication with the synthesis gas flow upstream of the secondary reformer.

19. The system further comprises a pre-reformer located upstream of the reformer, configured to receive a pre-reformer feed stream containing methane and reactants selected from the group consisting of water and carbon dioxide, and to generate the reformer feed stream, The apparatus according to claim 13, wherein the pre-reformer includes a pre-reform catalyst.

20. The apparatus according to claim 19, wherein the residue outlet port of the membrane separation system is in fluid flow communication with the pre-reformer supply flow.

21. The apparatus according to claim 13, wherein the tail gas conduit comprises a tail gas compressor.

22. The apparatus according to claim 13, wherein one or more burners are in fluid flow communication with the tail gas conduit.

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