Blue hydrogen method and equipment

Abstract

The present invention provides an apparatus and a process for producing hydrogen rich gas, the process comprising the steps of reforming hydrocarbon feed steam to syngas; the synthesis gas is shifted and the shifted gas is passed to a hydrogen purification unit, the CO2-rich off-gas from the hydrogen purification unit is subjected to carbon dioxide removal, and the hydrogen-rich CO2-lean off-gas is recycled to the process.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for producing hydrogen from a hydrocarbon feedstock, which includes: reforming, shift conversion, CO 2 removal, and hydrogen purification. Specifically, the present invention relates to an apparatus and method for producing hydrogen from a hydrocarbon feedstock, wherein the hydrocarbon feedstock is subjected to reforming in a reforming unit to produce syngas, the syngas is subjected to a shift conversion step, and then the shifted gas is processed in a hydrogen purification unit (such as a pressure swing adsorption (PSA) unit for hydrogen), whereby a hydrogen product and a tail gas stream rich in CO 2 are withdrawn, and wherein the tail gas stream rich in CO 2 is subjected to CO 2 removal to produce a CO-lean 2 stream, i.e., a CO-lean 2 tail gas stream, which is fed to the reforming unit; for example, the CO-lean 2 stream or a portion thereof is added as feed and / or fuel to the reforming unit, or as fuel in a combustion heater. The CO-lean 2 stream or a portion thereof can also be added to the shift conversion step and / or the hydrogen purification unit. The CO-lean 2 stream or a portion thereof can also be output, for example, outside the hydrogen purification unit, and more specifically, outside the apparatus.

[0002] Background

[0003] With the current demand and competition for hydrogen production, a great deal of effort has been devoted to developing optimized production of hydrogen equipment, with the aim of improving overall energy efficiency and reducing capital costs. The demand for more cost-effective hydrogen production has stimulated the development of technologies and catalysts for large-scale hydrogen production units in order to benefit from economies of scale.

[0004] Haldor Topsoe's latest innovations in hydrogen production technology and the development of a new generation of advanced catalysts ensure highly cost-effective hydrogen production and high equipment reliability, even in the case of large single-line capacities.

[0005] Applicant's WO 2020221642 A1 discloses an apparatus and method for producing hydrogen, which includes autothermal reforming (ATR) to produce syngas (synthesis gas), water gas shift, CO 2 removal of the shifted gas, and hydrogen purification to produce a hydrogen-rich gas and a tail gas stream. The tail gas stream is recycled to, for example, ATR, and prior thereto, the tail gas can be subjected to compression and membrane separation steps. When, for example, CO 2In the membrane separation unit, the permeate is the hydrogen-rich stream, which is then transferred to a hydrogen purification unit, such as a PSA unit, while the retentate is the hydrogen-lean stream, which is recycled to the feed side of the ATR or the feed side of the shift section.

[0006] It is desirable to improve such a method for producing hydrogen.

[0007] WO 2016187125 A1 discloses a method for incremental hydrogen production of an existing plant for producing hydrogen from natural gas. The existing plant includes steam reforming, water gas shift, and hydrogen purification carried out in a pressure swing adsorption (PSA) unit, thereby producing a first H 2 stream and a PSA tail gas stream. The PSA tail gas (the first waste stream) is compressed, dried, and CO 2 is removed from this stream in a cryogenic CO 2 separation unit. A remaining waste stream is produced and sent to a second PSA unit, from which a second H 2 stream, and a second PSA tail gas stream (the second waste stream) are withdrawn, and the second PSA tail gas stream is sent to a steam reformer as fuel gas.

[0008] US2013156685 discloses a method for reducing the total CO 2 production of a hydrogen production plant, including recovering carbon dioxide from the flue gas of a reformer (steam methane reformer, SMR). Three pre-reforming steps are carried out to produce a hydrocarbon feed to the reformer. The residual stream from the PSA unit downstream of the reformer is sent to a CO 2 separation unit, from which a hydrogen-rich 2 stream, a CO 2 stream, and a residual stream are produced. The residual stream is then recycled upstream of the reformer or used as fuel in the reformer. This citation at least does not mention: providing a reformer configuration other than a conventional SMR or ATR, providing a single pre-reformer (single-stage pre-reforming), and providing at least one flame heater for preheating the hydrocarbon feed before it is fed to the reformer.

[0009] It is also desirable to improve such methods and equipment for producing hydrogen. Summary of the Invention

[0011] Accordingly, an object of the present invention is to reduce the consumption of hydrocarbon feed and fuel in a hydrogen production plant and / or method, thereby improving energy efficiency, while increasing carbon dioxide capture, thereby reducing CO 2 emissions.

[0012] Another object of the present invention is to provide better integration of CO 2 removal in a hydrogen production plant and / or method.

[0013] The present invention solves these and other objects.

[0014] Accordingly, in a first aspect, there is provided an apparatus (100) for producing a hydrogen-rich stream (8) from a hydrocarbon feed (1), the apparatus comprising: 2 a reforming unit (110) arranged to receive the hydrocarbon feed (1, 2) and convert it into a synthesis gas stream (3);

[0015] a shift section (115, 150) which suitably includes a high-temperature or medium-temperature shift unit (115), the shift section being arranged to receive the synthesis gas stream (3) from the steam reforming unit (110) and suitably carry out a shift on it in a high-temperature or medium-temperature shift step, thereby providing a shifted synthesis gas stream (5);

[0016] a hydrogen purification unit (125) arranged to receive the shifted synthesis gas stream (5) and separate it into a high-purity H

[0017] stream as the hydrogen product (8), and a CO-rich 2 tail gas stream (9); 2 a CO

[0018] removal section (180) for removing CO 2 from the CO-rich 2 tail gas stream (9) to form a CO 2 product stream (11) and a CO-lean 2 tail gas stream (17, 17', 17''), 2 and wherein the apparatus is arranged to recycle at least the CO-lean

[0019] tail gas stream (17, 17', 17'') or a portion thereof back to the feed side of the reforming unit (110); 2 The apparatus further comprises:

[0020] at least one fired heater arranged to preheat the hydrocarbon feed (1, 2) and then feed it to the reforming unit (110) such as an ATR, and wherein the apparatus (100) is arranged to feed at least a portion of the CO-rich

[0021] tail gas stream (9) from the hydrogen purification unit (125) and / or at least a portion of the CO-lean 2 tail gas stream (17, 17', 17'') as fuel to the fired heater, and 2 wherein the CO

[0022] removal section (180) comprises two or more CO 2 removal units, and 2Separation unit, where the separation unit is selected from an amine washing unit, a CO 2 membrane, i.e., a CO 2 membrane separation unit, a CO 2 -PSA, a cryogenic separation unit, and combinations thereof, and

[0023] -where two or more CO 2 separation units can be of the same type or different types of units.

[0024] The present invention reduces the consumption of hydrocarbon feed and fuel in a hydrogen production apparatus and / or method, thereby improving energy efficiency, while increasing the capture amount of CO 2 and thus reducing the emissions of CO 2 Specifically, the present invention is based on the recognition that the recycled CO-rich 2 tail gas stream or a portion thereof from the hydrogen purification unit can be used both as the feed for the reforming unit and as the fuel for the fired heater. In addition, the present invention is based on the recognition that by using a CO 2 removal section including two carbon dioxide separation units and recycling the CO-rich 2 stream from the second CO 2 separation unit to the first CO 2 separation unit, the total CO 2 recovery rate from the CO 2 removal section can be maximized.

[0025] As further described below, in a second aspect of the present invention, there is also provided a method for producing a H-rich 2 stream from a hydrocarbon feed using the apparatus defined herein.

[0026] Further details of the present invention will be set forth in the following specification, drawings, aspects, and dependent claims.

[0027] As used herein, the term "the first aspect of the present invention" refers to the apparatus (system) according to the present invention; the term "the second aspect of the present invention" refers to the method according to the present invention.

[0028] As used herein, the term "comprising" also encompasses "consisting only of", i.e., "consisting of...".

[0029] As used herein, the term "appropriately" means "optionally", i.e., an optional embodiment.

[0030] As used herein, the term "at least a part" means at least a portion, such as at least a portion of a given stream. Thus, the term "at least a part" or "at least a portion" of a given stream refers to the entire stream or a portion thereof.

[0031] As used herein, the term "the present invention" or the abbreviation "invention" may be used interchangeably with the term "the present application" or the abbreviation "application".

[0032] Additional definitions are provided in connection with one or more of the following embodiments.

[0033] In one particular embodiment, the apparatus is arranged to directly recycle at least the lean CO 2 tail gas stream or a portion thereof to the feed side of the reforming unit. In another particular embodiment, the apparatus is arranged to directly feed as fuel for the flame heater to preheat the hydrocarbon feed the following streams: at least a portion of the rich CO 2 tail gas stream from the hydrogen purification unit, and / or at least a portion of the lean CO 2 tail gas stream.

[0034] As used herein, the term "directly" means that there are no intermediate steps or units that change the composition of the stream. For example, as shown in the drawings, apparatus 100 is arranged to directly recycle at least the lean CO 2 tail gas streams 17, 17', 17'' or a portion thereof to the feed side of reforming unit 110.

[0035] In one embodiment, the reforming unit is an autothermal reformer (ATR); a partial oxidation reformer (PO x ) ; a convective heating reformer, such as a heat exchanger reformer (HER) or a gas heating reformer (GHR); a steam methane reformer (SMR), such as an electrically heated steam methane reformer (e-SMR); or a combination thereof, such as a combination of SMR and (HER), or a combination of SMR and ATR, or a combination of ATR and HER.

[0036] All of the above reforming units are well known in the art.

[0037] For example:

[0038] - In an autothermal reformer (ATR), partial oxidation of the hydrocarbon feed by oxygen and steam occurs, followed by catalytic reforming; in autothermal reforming (ATR) (this also includes the term catalytic partial oxidation (CPO) herein), natural gas or other hydrocarbons react with steam and an oxidant (air, oxygen-enriched air or oxygen) in the presence of a nickel- or noble metal-based catalyst;

[0039] - In the non-catalytic partial oxidation (PO x ) of natural gas, light hydrocarbons, heavy hydrocarbons or solid feedstocks (such as coal) (also known as gasification) react with an oxidant (air, oxygen-enriched air or oxygen), and the obtained reactor outlet temperature is up to 1400 °C;

[0040] - A convective reformer, which may include one or more bayonet reforming tubes, such as an HTCR reformer, i.e., a Topsøe bayonet reformer, where the heat for reforming is transferred by convection as well as radiation;

[0041] - The term SMR encompasses conventional SMR and e-SMR; in conventional SMR (also known as a tubular reformer), the heat for reforming is mainly transferred by radiation in a radiant furnace; in an electrically heated steam methane reformer (e-SMR), electricity is used to generate the heat for catalytic reforming. Specifically, when using e-SMR, electricity from green energy sources such as wind power, hydropower, and solar power can be utilized, thereby further reducing the carbon dioxide footprint.

[0042] More information about these reformers is provided in detail in this document by direct reference to the applicant's patents and / or literature. For example, for tubular and autothermal reforming, an overview is given in the following document: "Tubular reforming and autothermal reforming of natural gas – an overview of available processes", Ib Fuel Processing Technology 42(1995)85-107; HTCR is described in EP 0535505, or HER is described in, for example, EP 2526045, or a process combining ATR and HER is described in, for example, EP 0983963. For a description of ATR and / or SMR (tubular reformer) for large-scale hydrogen production, see, for example, the following article: "Large-scale Hydrogen Production", Jens R. Rostrup-Nielsen and Thomas Rostrup-Nielsen", CATTECH, volume 6, pages 150–159(2002). For a description of the newer e-SMR technology, see, for example, WO2019 / 228797 A1.

[0043] In one embodiment, the catalyst in the reforming unit is a reforming catalyst, such as a nickel-based catalyst. In one embodiment, the catalyst in the water gas shift reaction (i.e., in the shift section) is any catalyst that is active for the water gas shift reaction. The two catalysts may be the same or different. Examples of reforming catalysts are Ni / MgAl 2 O 4 、Ni / Al 2 O 3 、Ni / CaAl 2 O 4, Ru / MgAl 2 O 4 , Rh / MgAl 2 O 4 , Ir / MgAl 2 O 4 , Mo 2 C, Wo 2 , CeO 2 , Ni / ZrO 2 , Ni / MgAl 2 O 3 , Ni / CaAl 2 O 3 , Ru / MgAl 2 O 3 , or Rh / MgAl 2 O 3 , which is a noble metal on an Al 2 O 3 support, but other suitable reforming catalysts are also conceivable. The catalytically active material can be Ni, Ru, Rh, Ir, or a combination thereof, and the ceramic coating can be Al 2 O 3 , ZrO 2 , MgAl 2 O 3 , CaAl 2 O 3 or a combination thereof, and may be mixed with oxides of Y, Ti, La, or Ce. The maximum temperature of the reactor can be between 850 - 1300 °C. The pressure of the feed gas can be 15 - 180 bar, preferably about 25 bar. The steam reforming catalyst is also known as the steam methane reforming catalyst or the methane reforming catalyst.

[0044] In a particular embodiment, the reforming unit is an autothermal reformer (ATR). The ATR enables operation of the plant and process at a low steam / carbon ratio, thus reducing the plant size. For example, the steam / carbon ratio of the syngas supplied from the ATR to the shift section is less than 2.0, preferably 0.3 - 1.0.

[0045] As used herein, the term "feed side" refers to the inlet side or simply the inlet. For example, the feed side of the reforming unit (e.g., ATR) refers to the inlet side of the ATR.

[0046] As used herein, the term CO 2 product stream refers to a stream containing 95 vol% or more (e.g., 99.5%) carbon dioxide.

[0047] CO lean 2 tail gas stream refers to a tail gas stream containing, for example, the following components: 85 mol% H 2 , 7 mol% CH4 , 7 mol% CO and 1 mol% N 2 + Ar. Thus, the CO-lean 2 tail gas stream is rich in hydrogen, i.e., contains more than 80 mol% H 2 , and is substantially free of carbon dioxide.

[0048] In one embodiment, the apparatus (100) does not have a CO 2 removal section arranged upstream of the hydrogen purification unit (125) and configured to receive the reformed gas stream (5) from the reforming section. Thus, the apparatus is arranged to directly provide (i.e., directly feed) the reformed syngas stream (5) to the hydrogen purification unit (125),

[0049] It has been found that recycling is advantageous, and thus the CO-lean 2 tail gas feed with a high hydrogen content is returned to the steam reforming unit while avoiding the use of a CO 2 removal between the reforming section and the hydrogen purification unit. This results in more methane being reformed into hydrogen and more CO being shifted to CO 2 . The benefits of this apparatus and method also include reduced hydrocarbon feed consumption, such as natural gas consumption, at the same required hydrogen production rate, while increasing the CO 2 capture amount, thereby reducing CO 2 emissions.

[0050] In addition, the CO 2 removal is carried out in a process gas stream (CO-rich 2 tail gas stream) that is much smaller than the reformed syngas stream.

[0051] The CO 2 product stream from the CO 2 removal step can be stored or used for other purposes to reduce the CO 2 emissions to the atmosphere.

[0052] An improvement of the process is thus obtained, in particular by better integrating the CO 2 removal process, thereby providing a superior blue hydrogen process by which carbon dioxide can be removed while generating a hydrogen product.

[0053] The term "blue hydrogen" refers to the production of hydrogen from a hydrocarbon feed (such as natural gas), supported by carbon capture and its storage or utilization.

[0054] In one embodiment, the CO 2 removal section includes a hydrogen PSA and a CO 2 -PSA. In one embodiment, the CO 2 removal section includes a cryogenic separation unit and a CO2 -Combination of PSA. In one embodiment, CO 2 The removal section includes a cryogenic separation unit and a combination of a CO 2 membrane separation unit.

[0055] Especially when using a CO 2 membrane separation unit, the permeate is a hydrogen-rich stream, which can then be sent to a hydrogen purification unit, such as a PSA unit, while the retentate is a hydrogen-lean stream, which is recycled to the feed side of the ATR, or the feed side of the shift section, or the feed side of the membrane separation, i.e., the inlet side.

[0056] CO 2 The removal section can also be a Benfield process or apparatus, including an absorber for performing a gas absorption step and a regenerator for performing a carbonate regeneration step. As is well known in the art, CO 2 The removal section can also be in the form of CO 2 -PSA. In one embodiment, CO 2 The removal section includes a hydrogen PSA.

[0057] In one embodiment, the apparatus (100) further includes a prereformer unit (140) disposed upstream of the reforming unit (110), the prereformer unit (140) being arranged to prereform the hydrocarbon feed (1) before feeding it to the steam reforming unit (110), and wherein the apparatus (100) is arranged to feed at least a portion of the CO-lean 2 tail gas stream (17, 17') to the feed side of the prereformer unit (140); and / or

[0058] -The apparatus (100) is arranged to feed at least a portion of the CO-lean 2 tail gas stream (17) to the feed side of the shift section; and / or

[0059] The apparatus is arranged to feed at least a portion of the CO-lean 2 tail gas stream to the feed side of the hydrogen purification unit (125).

[0060] As used herein, the terms "prereformer", "prereformer unit" and "prereforming unit" may be used interchangeably.

[0061] In one embodiment, the prereformer unit is an adiabatic prereformer unit.

[0062] By providing a single prereformer unit (such as an adiabatic prereformer unit), a simpler apparatus and method can be provided. The associated capital expenditure (CapEx) and operating expenditure (OpEx) for providing additional prereformers and related heat exchange units are eliminated.

[0063] As used herein, the feed side of a shift section refers to the inlet side of a high-temperature or medium-temperature shift unit, or the inlet side of any downstream shift unit (e.g., a medium-temperature shift unit arranged downstream of a high-temperature shift unit) downstream of said shift section.

[0064] Recirculating the CO-lean 2 tail gas stream to, for example, an ATR has the advantage of reducing the flow to the prereformer, thereby reducing its size. More specifically, recirculating the CO-lean 2 tail gas increases the hydrogen recovery rate, thereby reducing the feed consumption. Therefore, the size of the upstream equipment can be reduced.

[0065] Recirculating the CO-lean 2 tail gas stream to the shift section has the advantage of reducing the size of both the ATR and the prereformer. This recirculation option is preferably combined with a second H 2 purification step of the tail gas appropriately upstream of the CO 2 removal section to reduce the H 2 partial pressure.

[0066] In one embodiment, the apparatus does not include, i.e., there is no steam methane reforming unit (SMR) upstream of the ATR. Thus, the reforming section, i.e., the reforming unit therein, includes the ATR, and optionally a prereforming unit, but no steam methane reforming (SMR) unit, i.e., the use of, for example, a conventional SMR (commonly also referred to as a radiant furnace or tubular reformer) is omitted. Thus, in one embodiment, the reforming unit is the ATR, and the one prereformer unit is arranged upstream thereof. The ATR together with the prereformer unit (i.e., the standalone ATR) is a simple and energy-efficient solution for the reforming section.

[0067] This has significant advantages in terms of energy consumption and equipment size, because now, among other things, it is possible to operate at a steam / carbon molar ratio far below 1, thereby significantly reducing the amount of steam carried in the equipment / method, as further described above.

[0068] Suitably, the apparatus further includes a hydrogenator unit and a sulfur absorption unit arranged upstream of the prereformer unit, wherein the apparatus is arranged to feed at least a portion of the CO-lean 2 tail gas stream to the feed side of the hydrogenator unit.

[0069] In one embodiment, the apparatus further includes:

[0070] - a compressor, i.e., a CO-rich 2 tail gas recirculation compressor, which is arranged to compress the CO-rich 2 tail gas stream (9), and the compressor is installed in the CO 2Upstream of the removal section (180); and a compressor optionally installed downstream of the CO 2 removal section (180) for recycling the lean CO 2 gas stream (17, 17', 17”) or a portion thereof to the feed side of the reforming unit (140), and / or the feed side of the shift section, and / or the feed side of the pre-reformer unit (140), and / or the feed side of the hydrogen purification unit (125).

[0071] By returning the lean CO 2 tail gas addition to the reforming section (e.g., pre-reformer and / or ATR), the present invention is also capable of reducing the power consumption of the rich CO 2 tail gas recycle compressor.

[0072] By directly becoming part of the hydrocarbon feed or process gas being processed in, for example, a pre-reformer, ATR or shift section, at least a portion of the compressed portion of the lean CO 2 tail gas stream is used in the method.

[0073] Suitably, the high temperature shift unit comprises a promoted zinc-aluminum oxide-based high temperature shift catalyst which is preferably arranged in the HTS unit in the form of one or more catalyst beds, and preferably wherein, based on the weight of the oxidized catalyst, the promoted zinc-aluminum oxide-based HT shift catalyst in its active form comprises a Zn / Al molar ratio of 0.5 to 1.0, an alkali metal content of 0.4 to 8.0 wt% and a copper content of 0 - 10%.

[0074] In conventional hydrogen production plants, the standard use of an iron-based high temperature shift catalyst requires a steam / carbon ratio of about 3.0 to avoid the formation of iron carbide.

[0075] (1)

[0076] The formation of iron carbide weakens the catalyst particles and may lead to catalyst disintegration and an increase in pressure drop.

[0077] Iron carbide will catalyze the formation of Fischer-Tropsch by-products

[0078] (2)

[0079] The Fischer-Tropsch reaction consumes hydrogen, thus reducing the efficiency of the shift section.

[0080] However, according to the present invention, a non-iron catalyst is used, such as a promoted zinc-aluminum oxide-based catalyst. For example, Topsøe SK-501Flex TM HT shift catalyst, which is capable of enabling the reforming section and the high temperature shift section to operate at a steam / carbon ratio as low as 0.3.

[0081] Thus, the apparatus and / or method of the present application operates at a steam / carbon ratio as low as 0.3, which is in contrast to current conventional hydrogen apparatuses that are based on reforming and / or shift sections operating at a steam / carbon ratio of about 1.5 or higher. In an advantageous embodiment of the method, the zinc-aluminum oxide-based catalyst in its active form comprises a mixture of zinc aluminate spinel and zinc oxide, and an alkali metal selected from Na, K, Rb, Cs, and mixtures thereof, and optionally Cu. As described above, based on the weight of the oxidized catalyst, the Zn / Al molar ratio of the catalyst can be from 0.5 to 1.0, the alkali metal content is from 0.4 to 8.0 wt%, and the copper content is from 0 to 10%.

[0082] The high-temperature shift catalyst employed in accordance with the present method is not restricted by strict steam / carbon ratio requirements, thereby allowing the steam / carbon ratio in the shift section and the reforming section to be reduced.

[0083] Likewise, the amount of steam carried in the apparatus and / or method is significantly reduced, thereby reducing the apparatus size and energy consumption. More specifically, a steam / carbon ratio of less than 2.0 has several advantages. Overall reduction of the steam / carbon ratio results in reduced feed and steam flow rates through the reforming section and the downstream cooling and hydrogen purification sections. Compared to a high steam / carbon ratio, a low steam / carbon ratio in the reforming section and the shift section also enables a higher syngas flux. The reduced mass flow rate through these sections means smaller apparatus and pipeline sizes. The reduced mass flow rate also results in less generation of low-temperature heat, which is typically not utilizable. This means there is potential to reduce capital expenditure (CapEx) and operating expenditure (OpEx).

[0084] Since the requirements for the steam / carbon ratio in the high-temperature shift step of the present method are significantly lower compared to the prior art, the present invention can reduce the steam / carbon ratio at the front end to, for example, 0.6 or as low as possible, depending on the possible shift solutions, as further explained below. For ATR and the overall method, the advantage of a low steam / carbon ratio is that the apparatus required at the front end is smaller due to the lower total mass flow rate through the apparatus.

[0085] It should be understood that the term "front end" refers to the reforming section. It should also be understood that the reforming section is a part of the apparatus that includes the units before the reforming unit and includes the reforming unit, such as ATR, or a pre-reforming unit and ATR, or a hydrogenator and a sulfur absorber and a pre-reforming unit and ATR.

[0086] The apparatus may preferably further comprise an air separation unit (ASU) that is arranged to receive an air stream and produce an oxygen stream, which is then fed through a pipeline to the ATR.

[0087] The device preferably further comprises a pipeline for adding steam to the hydrocarbon feed, the oxygen-containing stream and the ATR, and optionally also to the inlet of the reforming section (e.g., added to the main hydrocarbon feed), and also to the inlet of the shift section (especially added to the HTS unit), and / or added to an additional shift unit downstream of the HTS unit, as will be further described below.

[0088] According to the present invention, the device further comprises at least one flame heater, which is arranged to preheat the hydrocarbon feed (1, 2) before the hydrocarbon feed (1, 2) is fed into the reforming unit (110), such as the ATR, wherein the device (100) is arranged to feed at least a part of the CO-rich 2 tail gas stream (9) from the hydrogen purification unit (125) and / or at least a part of the CO-lean 2 tail gas stream (17, 17', 17”) as fuel to the flame heater.

[0089] This enables a low carbon emission of the flue gas generated from the combustion of the flame heater. Separate fuel gas and / or hydrogen fuel gas and combustion air are suitably used in the flame heater. The consumption of the fuel gas (e.g., natural gas) commonly used for combustion is significantly reduced or eliminated. In addition to preheating the hydrocarbon feed gas entering the pre-reformer and, for example, the ATR, the flame heater can also be used to superheat steam, for example.

[0090] The device further comprises a flame heater for heating the pre-reformer, wherein the device (100) is arranged to feed at least a part of the CO-rich 2 tail gas stream (9) from the hydrogen purification unit (125) and / or at least a part of the CO-lean 2 tail gas stream (17, 17', 17”) as fuel to the flame heater.

[0091] In one embodiment, the device further comprises a flame heater for heating the reforming unit (110), wherein the device (100) is arranged to feed at least a part of the CO-rich 2 tail gas stream (9) from the hydrogen purification unit (125) and / or at least a part of the CO-lean 2 tail gas stream (17, 17', 17”) as fuel to the flame heater.

[0092] Suitably, the CO-lean 2 tail gas stream (17, 17”) is mixed with the hydrocarbon feed (2) before being fed to the feed side of the steam reforming unit (110), such as the ATR; or the CO-lean 2 tail gas stream (17, 17') is mixed with the hydrocarbon feed (1) before being fed to the feed side of the pre-reformer unit (140).

[0093] Therefore, it should be understood that the CO-lean 2 tail gas can be directly directed to, for example, the ATR, and / or mixed with the hydrocarbon feed before entering the ATR. Equally suitable is that the CO-lean 2 tail gas stream is mixed with the hydrocarbon feed and then fed to the feed side of the pre-reformer unit.

[0094] In another embodiment, the hydrogen purification unit is selected from a pressure swing adsorption (PSA) unit, a hydrogen membrane, or a cryogenic separation unit.

[0095] In another embodiment, the apparatus has no second (additional) hydrogen purification unit, such as a second PSA unit, downstream of the CO 2 removal section. Thus, there is no need to further enrich the CO-lean 2 tail gas into a separate H 2 product, since the CO-lean 2 tail gas may already have the specifications required to be recycled at least to the feed side of the reformer unit. Thus, the CO-lean 2 tail gas is recycled at least directly to the feed side of the reformer unit. In other words, according to this embodiment, the apparatus is arranged to recycle at least directly the CO-lean 2 tail gas stream or a portion thereof at least directly to the feed side of the reformer unit, i.e., providing a conduit for recycling at least directly the CO-lean 2 tail gas stream or a portion thereof at least directly to the feed side of the reformer unit (110).

[0096] In another embodiment, the shift section includes one or more additional high temperature shift units in series.

[0097] In another embodiment, the shift section further includes one or more additional shift units located downstream of the high temperature shift unit. In a particular embodiment, the one or more additional shift units are one or more medium temperature shift units and / or one or more low temperature shift units.

[0098] Providing additional shift units or shift steps increases the flexibility of the apparatus and / or method when operating at a low steam / carbon ratio. A low steam / carbon ratio may result in a shift conversion rate lower than the optimum value, which means that in some embodiments, providing one or more additional shift steps may be advantageous. The one or more additional shift steps may include medium temperature (MT) shift and / or low temperature (LT) shift and / or high temperature shift. Generally speaking, the more CO is converted in the shift step, the more H 2 is obtained and the smaller the front end required.

[0099] This can also be seen from the exothermic shift reaction:

[0100] As described above, steam can optionally be added before and after the high temperature shift step, for example before one or more subsequent MT or LT shift and / or HT shift steps, in order to maximize the performance of said subsequent HT, MT and / or LT shift steps.

[0101] Two or more high temperature shift steps in series (for example, the high temperature shift step includes two or more shift reactors in series, and cooling and / or steam addition can be carried out between them) may have advantages because it can provide a higher shift conversion rate at high temperature, which may reduce the required volume of shift catalyst, and thus may reduce CapEx. In addition, high temperature can reduce the formation of methanol (a typical by-product of the shift step).

[0102] Preferably, the MT and LT shift steps can be carried out on a promoted copper / zinc / aluminum oxide catalyst. For example, the low temperature shift catalyst type can be LK-821-2, which is characterized by high activity, high strength and high tolerance to sulfur poisoning. A top layer of special catalyst can be installed to capture chlorine that may be present in the gas and prevent droplets from reaching the shift catalyst.

[0103] The MT shift step can be carried out at a temperature of 190–360 °C.

[0104] The LT shift step can be carried out at a temperature of T 露点 +15 - 290 °C, for example 200 - 280 °C. For example, the low temperature shift inlet temperature is T 露点 +15 - 250 °C, for example 190 - 210 °C.

[0105] Reducing the steam / carbon ratio results in a lower dew point of the process gas, which means that the inlet temperature of the MT and / or LT shift steps can be reduced. A lower inlet temperature may mean a lower CO escape at the outlet of the shift reactor, which is also beneficial for the equipment and / or method.

[0106] In a second aspect of the present invention, there is also provided a method for producing a hydrogen product (8) from a hydrocarbon feed (1, 2), said method comprising the following steps:

[0107] Providing an apparatus (100) according to any of the foregoing embodiments of the first aspect of the present invention;

[0108] Supplying the hydrocarbon feed (2) to a reforming unit such as an ATR (110) and converting it into a synthesis gas stream (3);

[0109] Supplying the synthesis gas stream (3) from the reforming unit (110) to a shift section and carrying out a shift on it in a shift step (115), suitably in a high temperature or medium temperature shift step (115), so as to provide a shifted synthesis gas stream (5);

[0110] The transformed gas stream (5) from the conversion section is supplied to a hydrogen purification unit (125) and separated into a high-purity H 2 stream as the hydrogen product (8), and a CO-rich 2 tail gas stream (9); and

[0111] The method further includes:

[0112] - providing an optional step of compressing the CO-rich 2 tail gas stream (9), i.e., the CO-rich 2 tail gas compression step; and a CO 2 removal step in a CO 2 removal section (180), thereby providing a step of removing CO 2 from the optionally compressed CO-rich 2 tail gas stream (9) to form a CO 2 product stream (11) of the CO-rich 2 tail gas stream and a CO-lean 2 tail gas stream (17, 17', 17''), the optional step of compressing the CO-rich 2 tail gas stream (9) being carried out before the CO 2 removal section (180), and

[0113] - feeding at least a portion of the CO-rich 2 tail gas stream (9) from the hydrogen purification unit (125) and / or the CO-lean 2 tail gas stream (17, 17', 17'') or a portion thereof, optionally via an additional compression step, as a fuel feed to at least one fired heater, the fired heater being arranged to preheat the hydrocarbon feed (1, 2) and then feed it to a reforming unit (110), and optionally also to the feed side of a steam reforming unit (110), and / or the feed side of a conversion section, and / or the feed side of a hydrogen purification unit (125), and / or the feed side of an optional prereformer unit (140) arranged upstream of the reforming unit (110), and

[0114] - wherein the CO 2 removal section (180) includes two or more CO 2 separation units selected from amine scrubbing units, CO 2 membranes i.e., CO 2 membrane separation units, CO 2 -PSA, cryogenic separation units, and combinations thereof, and

[0115] - wherein two or more CO 2The separation units can be units of the same type or different types.

[0116] As described above with respect to the first aspect of the present invention, the apparatus and / or method of the present invention can operate at a steam / carbon ratio as low as 0.3. Compared with a high steam / carbon ratio, a low steam / carbon ratio in the reforming section and the shift section (i.e., optionally including any steam added to the shift section) enables a higher syngas flux.

[0117] In another embodiment according to the second aspect of the present invention, the temperature in the high-temperature shift step is in the range of 300 - 600 °C, for example 360 - 470 °C, or for example 345 - 550 °C. This means that according to the method, a high-temperature shift reaction can be carried out on a feed with a much lower steam / carbon ratio than in known methods. For example, the high-temperature shift inlet temperature can be 300 - 400 °C, for example 350 - 380 °C.

[0118] For example, when operating using ATR, the carbon feed to the ATR is mixed with oxygen and additional steam in the ATR, and a combination of at least two types of reactions occurs. These two reactions are combustion and steam reforming.

[0119] Combustion zone:

[0120]

[0121] Heat and catalytic zone:

[0122]

[0123] The combustion of methane to form carbon monoxide and water (Reaction (4)) is a highly exothermic process. When all the oxygen has been converted, there may be excess methane at the outlet of the combustion zone.

[0124] The heat zone is part of the combustion chamber where the hydrocarbons are further converted by homogeneous gas-phase reactions, mainly Reactions (5) and (6). The endothermic steam reforming of methane (5) consumes most of the heat generated in the combustion zone.

[0125] There can be a fixed catalyst bed behind the combustion chamber, i.e., the catalytic zone, where the final hydrocarbon conversion occurs through heterogeneous catalytic reactions. At the outlet of the catalytic zone, the syngas preferably approaches the equilibrium state of Reactions (5) and (6).

[0126] By means of the present invention, the apparatus and / or method can be operated without adding additional steam between the reforming step and the high-temperature shift step.

[0127] Suitably, the space velocity in the ATR is very low, for example less than 20000 Nm 3 C / m 3 / h, preferably less than 12000 Nm3 C / m 3 / h, most preferably less than 7000 Nm 3 C / m 3 / h. The space velocity is defined as the volumetric carbon flow per catalyst volume and is thus independent of the conversion in the catalyst zone.

[0128] Any embodiment of the first aspect (apparatus) of the present invention can be used in combination with any embodiment of the second aspect (method) of the present invention, and vice versa. Any relevant benefits according to the embodiments of the first aspect of the present invention can be used in combination with the embodiments according to the second aspect of the present invention.

[0129] Advantages of the present application include:

[0130] - Reducing the consumption of hydrocarbon feed (such as natural gas) while producing the same amount of hydrogen, and at the same time increasing the CO 2 capture amount, thereby reducing CO 2 emissions;

[0131] - Since a part of the CO-lean 2 tail gas is also used as fuel for the flame heater, the carbon emissions from the flue gas generated by the flame heater are very low;

[0132] - By returning the CO-lean 2 tail gas to the reforming unit, the power consumption of the rich-CO 2 tail gas recycle compressor for compressing the rich-CO 2 tail gas stream is reduced.

[0133] Brief Description of the Drawings

[0134] Figure 1 Shows the layout of an ATR-based hydrogen production method and apparatus with a CO 2 separation unit.

[0135] Figure 2 Shows the layout of an ATR-based hydrogen production method and apparatus according to an embodiment of the present invention.

[0136] Detailed Description

[0137] Figure 1Device 100 is shown, in which a hydrocarbon feed 1 (i.e., a main hydrocarbon feed 1, such as natural gas) is sent to a reforming section, which includes a pre-reformer unit 140 and a reforming unit (shown here as an autothermal reformer 110). The reforming section may also include a hydrogenator and a sulfur absorber unit (not shown) upstream of the pre-reformer unit 140. The hydrocarbon vapor 1 is mixed with steam 13. The resulting hydrocarbon feed 2 is sent to the ATR 110, as is the oxygen 15 and the steam 13. The oxygen stream 15 is produced by means of an air separation unit (ASU) 145, and air 14 is fed to this air separation unit. In the ATR 110, the hydrocarbon feed 2 is converted into a synthesis gas stream 3, which is then sent to the shift section 115, 150.

[0138] The shift section includes, for example, a high-temperature shift (HTS) unit 115, to which additional or extra steam 13' may also be added upstream. The shift section may also include additional shift units, such as a low-temperature shift (LTS) unit 150. It should be understood that the shift section may include any one of, or a combination of, HTS, MTS, and LTS. Additional or extra steam 13' may also be added downstream of the HTS unit 115 but upstream of the low-temperature shift unit 150. Then, the shifted gas stream 5 is fed (e.g., directly fed) from the shift section to a hydrogen purification unit 125 (e.g., a PSA unit), from which a high-purity H 2 stream, as the hydrogen product 8, and a CO-rich 2 tail gas stream 9 are produced. This CO-rich 2 tail gas recycle stream 9 is directed via a recycle compressor (not shown) to a CO 2 removal section 180, from which a CO 2 product stream 11 and a CO-lean 2 tail gas streams 17, 17', 17'' are produced. Device 100 is arranged to recycle (e.g., directly recycle) the CO-lean 2 tail gas streams 17, 17', 17'' or a portion thereof to the feed side of the pre-reformer 140, or to the feed side of the reforming unit (here the ATR 110), or to the shift section (not shown). Device 100 also includes at least one flame heater (not shown), which is arranged to preheat the hydrocarbon feeds 1, 2 and then feed them to the pre-reformer unit 140 or the reforming unit 110, and the device (100) is arranged to use at least a portion of the CO-rich 2 tail gas stream 9 from the hydrogen purification unit 125, or at least a portion of the CO-lean 2 tail gas streams 17, 17', 17'' as fuel feed (e.g., directly feed) to the flame heater.

[0139] Figure 2 Device 100 is shown using the same units and reference numerals as Figure 1 above, in which,Figure 1 has a CO in it 2 CO of the separation unit 2 The removal section 180 includes two COs 2 COs of the separation units 181 and 182 2 is replaced by the removal section. The CO-rich 2 tail gas recycle stream 9 is guided via a recycle compressor (not shown) to the first CO 2 separation unit 181, which produces a first CO-lean 2 stream 10 and CO 2 product stream 11. The first CO-lean 2 stream 10 is fed to the second CO 2 separation unit 182, which produces a CO-lean 2 tail gas stream 17, 17', 17'' and a CO-rich 2 stream 12, which is recycled to upstream of the first CO 2 separation unit 181. The CO-lean 2 tail gas stream or a part thereof 17, 17', 17'' is recycled to the feed side of the prereformer 140, or to the feed side of the reforming unit (here ATR 110), or to the shift section (not shown). By using a CO 2 removal section including two separation units 181 and 182 2 and recycling the CO-rich 2 stream 12 from the second CO 2 separation unit 182 to upstream of the first CO 2 separation unit 181, the total CO 2 recovery from the CO 2 removal section can be maximized. Example

[0140] In a method and apparatus 100 for removing carbon dioxide from a CO-rich 2 syngas 5, after removing the CO 2 as a CO 2 product stream 11, a CO-lean 2 tail gas 17 is generated in the CO 2 removal section 180. The CO-lean 2 tail gas may have the following composition: hydrogen 85 mol%, methane 7 mol%, CO 7 mol%, nitrogen + argon 1 mol%. The CO-lean 2 tail gas 17 is directly recycled back to the reforming unit 110, here specifically taking ATR as an example, and further having a prereformer unit 140 upstream. This results in more methane being reformed into hydrogen and more CO being shifted to CO 2Benefits of this include reducing the consumption of hydrocarbon feed (e.g., natural gas) at the same required hydrogen production rate while increasing the capture of CO 2 and thus reducing CO 2 emissions. A portion of the CO-lean 2 tail gas is also used as fuel for the fired heater. This results in very low carbon emissions from the flue gas generated in the fired heater. Additionally, by returning the CO-lean 2 tail gas addition back to the reforming unit 110 (here the ATR), the power consumption of the compressor arranged to compress the CO-rich 2 tail gas stream 9, i.e., the CO-rich 2 tail gas recycle compressor (not shown in the figure) is reduced.

Claims

1. An apparatus (100) for producing a hydrogen product (8) from a hydrocarbon feed (1), the apparatus comprising: - a reforming unit (110) arranged to receive a hydrocarbon feed (1, 2) and convert it into a synthesis gas stream (3); a shift section (115, 150) arranged to receive a synthesis gas stream (3) from a steam reforming unit (110) and shift it, thereby providing a shifted synthesis gas stream (5); a hydrogen purification unit (125) arranged to receive the shifted synthesis gas stream (5) and to separate it into a high purity H2 stream as the hydrogen product (8), and a CO2-rich tail gas stream (9); a CO 2 removal section ( 180 ) for removing CO 2 from the CO 2 -rich tail gas stream ( 9 ) to form a CO 2 product stream ( 11 ) and a CO 2 -lean tail gas stream ( 17 , 17 ′, 17 ″), wherein the apparatus is arranged to recycle the CO2-lean tail gas stream (17, 17', 17") or a portion thereof at least to the feed side of the reforming unit (110); - wherein the apparatus further comprises at least one fired heater, which is arranged to preheat the hydrocarbon feed (1, 2) before feeding it to the reforming unit (110), and wherein the apparatus (100) is arranged to feed at least a portion of the CO2-rich tail gas stream (9) from the hydrogen purification unit (125) and / or at least a portion of the CO2-lean tail gas stream (17, 17', 17") as fuel to the fired heater, and - wherein the CO2 removal section (180) comprises two or more CO2 separation units selected from the group consisting of an amine wash unit, a CO2 membrane, i.e., a CO2 membrane separation unit, a CO2-PSA, a cryogenic separation unit, and combinations thereof, and - wherein the two or more CO2 separation units may be units of the same type or of different types.

2. The apparatus according to claim 1, wherein: - The conversion section (115, 150) comprises a high-temperature or medium-temperature conversion unit (115).

3. The apparatus according to any one of claims 1 to 2, wherein the reforming unit is an autothermal reformer (ATR); a partial oxidation reformer (PO x ); a convection heated reformer, such as a heat exchanger reformer (HER) or a gas heated reformer (GHR); a steam methane reformer (SMR), such as an electrically heated steam methane reformer (e-SMR); or a combination thereof, such as a combination of SMR and (HER), or a combination of SMR and ATR, or a combination of ATR and HER.

4. The apparatus according to any one of claims 1 to 3, wherein the apparatus is arranged to provide the shifted synthesis gas stream (5) directly to the hydrogen purification unit (125).

5. The device according to any one of claims 1 to 4, wherein - the apparatus (100) further comprises a pre-reformer unit (140) arranged upstream of the reforming unit (110), the pre-reformer unit (140) being arranged to pre-reform the hydrocarbon feed (1) before feeding it to the reforming unit (110), and wherein the apparatus (100) is arranged to feed at least a portion of the CO2-lean tail gas stream (17, 17') to the feed side of the pre-reformer unit (140); and / or - the device (100) is arranged to feed at least part of the CO2-lean tail gas stream (17) to the feed side of the shift stage; and / or The apparatus is arranged to feed at least a portion of the CO2-lean tail gas stream to the feed side of a hydrogen purification unit (125).

6. The apparatus according to any one of claims 1 to 5, further comprising: a compressor, i.e. a CO2-rich tail gas recirculation compressor, arranged to compress the CO2-rich tail gas stream (9), the compressor being installed upstream of the CO2 removal section (180); and an optional compressor installed downstream of the CO2 removal section (180) for recycling the CO2-lean gas stream (17, 17', 17") or a portion thereof to the feed side of the reforming unit (140), and / or the feed side of the shift section, and / or the feed side of the pre-reformer unit (140), and / or the feed side of the hydrogen purification unit (125).

7. The apparatus according to any one of claims 5-6, wherein the reforming unit (110) is an ATR and the one pre-reformer unit (140) is arranged upstream thereof.

8. The apparatus (100) according to any one of claims 1 to 7, wherein the hydrogen purification unit (125) is selected from a pressure swing adsorption (PSA) unit, a hydrogen membrane or a cryogenic separation unit.

9. The apparatus according to any one of claims 1 to 8, wherein the apparatus is arranged to recycle the CO2-lean tail gas stream (17, 17', 17") or a portion thereof at least directly to the feed side of the reforming unit (110).

10. A method for producing a hydrogen product (8) from a hydrocarbon feed (1, 2), the method comprising the steps of: Providing an apparatus (100) according to any one of the preceding claims; Supplying a hydrocarbon feed (2) to a reforming unit and converting it into a synthesis gas stream (3); supplying a synthesis gas stream (3) from a reforming unit (110) to a shift section and shifting it in a shift step, suitably a high temperature or medium temperature shift step (115), thereby providing a shifted synthesis gas stream (5); The shifted gas stream (5) from the shift section is supplied to a hydrogen purification unit (125) and separated into a high purity H2 stream as said hydrogen product (8), and a CO2-rich tail gas stream (9); and The method further includes: - providing an optional step of compressing the CO2-rich tail gas stream (9), i.e. a CO2-rich tail gas compression step; and a CO2 removal step in the CO2 removal section (180), thereby providing a step of removing CO2 from the CO2-rich tail gas stream (9) thus optionally compressed into a CO2-rich tail gas stream and a CO2-lean tail gas stream (17, 17', 17") as a CO2 product stream (11), the optional step of compressing the CO2-rich tail gas stream (9) being carried out before the CO2 removal section (180), and - feeding at least a portion of the CO2-rich tail gas stream (9) from the hydrogen purification unit (125) and / or the CO2-lean tail gas stream or a portion thereof (17, 17', 17"), optionally via a further compression step, as fuel to at least one fired heater, which is arranged to preheat the hydrocarbon feed (1, 2) and then feed it to the reforming unit (110), and optionally additionally also to the feed side of the reforming unit (110), and / or to the feed side of the shift stage, and / or to the feed side of the hydrogen purification unit (125), and / or to the feed side of an optional pre-reformer unit (140) arranged upstream of the reforming unit (110), and - wherein the CO2 removal section (180) comprises two or more CO2 separation units selected from the group consisting of an amine wash unit, a CO2 membrane, i.e., a CO2 membrane separation unit, a CO2-PSA, a cryogenic separation unit, and combinations thereof, and - wherein the two or more CO2 separation units may be units of the same type or of different types.

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