WO2025247773A1

WO2025247773A1 - Autothermal reforming system and process for hydrogen production

Info

Publication number: WO2025247773A1
Application number: PCT/EP2025/064312
Authority: WO
Inventors: Michael Edward HUCKMAN; Jorge JIMENEZ UMANA
Original assignee: SABIC Global Technologies BV
Current assignee: SABIC Global Technologies BV
Priority date: 2024-05-27
Filing date: 2025-05-23
Publication date: 2025-12-04
Anticipated expiration: 2026-11-27

Abstract

An autothermal reformer (ATR) system and process for producing a hydrogen-rich product from a hydrocarbon feed. The ATR system includes: a hydrocarbon feed preheating section arranged to receive the hydrocarbon feed and apply thermal energy from electrical heating to the hydrocarbon feed to produce a preheated hydrocarbon feed; an autothermal reformer unit arranged to receive the preheated hydrocarbon feed and convert it to a syngas product; a shift conversion section arranged to receive the syngas product and convert it to a shifted syngas product; and a hydrogen purification unit arranged to receive the shifted syngas product and convert it to a hydrogen-rich product and an offgas product.

Description

AUTOTHERMAL REFORMING SYSTEM AND PROCESS

FOR HYDROGEN PRODUCTION

TECHNICAL FIELD

[0001] The present disclosure relates to autothermal reforming systems and processes for producing hydrogen from a hydrocarbon feed. The autothermal reforming system uses electrical heating to provide the thermal energy necessary to preheat the hydrocarbon feed thereby eliminating the need for a fired heater.

BACKGROUND

[0002] Industrial processes, such as reforming hydrocarbon feeds to produce syngas and hydrogen, will need to capture carbon dioxide to mitigate the effects of climate change. There are two basic types of reforming technologies: steam methane reforming (SMR) and autothermal reforming (ATR). Both work by exposing a hydrocarbon feed and steam to a catalyst at high temperature.

[0003] SMR is the most common reforming technology and uses air-fired combustion to generate the heat needed to preheat the hydrocarbon feed and to drive the reforming reactions in the steam methane reformer. During a conventional SMR process the following two reactions take place:

CH4 + 2 H2 — ► CO2 + 4 H2

CH4 + H2O — ► CO + 3 H₂.

A water-gas shift reaction is subsequently performed using steam to convert carbon monoxide to carbon dioxide and generate additional hydrogen. This is typically followed by a pressure swing adsorption step to purify the hydrogen. Air-fired combustion in the fired preheater generates a flue gas containing carbon dioxide at low pressure and concentration due to the high amounts of inert nitrogen contributed by the air. Carbon capture from the flue gas is costly, inefficient, and bulky. Eliminating air-fired combustion in a fired preheater not only makes efficient capture of 100% of the carbon dioxide in the process possible, but it also reduces capital costs by eliminating the need to handle the nitrogen in the air.

[0004] In ATR, oxygen is added to the process resulting in two additional exothermic reactions:

CH₄ + O2— ► CO2 + 2 H2

CH₄ + y₂ or- co + 2 H₂. ATR can achieve relatively high carbon capture compared to conventional steam/hydrocarbon reforming since a majority of the carbon dioxide produced in the oxy gen-fired reformer can be recovered from the high pressure syngas stream using conventional acid gas removal operations. However, a fired heater is required in a conventional ATR process to preheat the hydrocarbon feed which, like in the SMR process above, produces a flue gas containing carbon dioxide that is difficult to capture. Accordingly, a need exists for an improved ATR system and process whereby an amount of fuels, especially fossil fuels, burned to provide energy in order to preheat the hydrocarbon feed is substantially reduced or eliminated.

SUMMARY

[0005] The present disclosure relates to an autothermal reforming (ATR) system and process for producing hydrogen from a hydrocarbon feed that uses electrical heating to provide all heating duties necessary to preheat the hydrocarbon feed thereby eliminating the need for a fired preheater.

[0006] The fired heater adds a significant amount of capital cost to an ATR process, consumes fuel and emits carbon dioxide. The carbon dioxide emission from the fired preheater can typically range from 5-10% of the total carbon dioxide generated in an ATR process and is at low pressure, making it economically impractical to capture this portion of carbon dioxide from the overall process. The current disclosure is based on a realization that the fired preheater is not necessary for an ATR process from the heat balance point of view; the heat required for all preheating functions that would conventionally be carried out in the fired preheater can be provided entirely by electrical heating. Therefore, the fired preheater can be eliminated by shifting those preheating functions from the fired heater to electrical heating. Not only does eliminating the fired preheater eliminate the fired preheater capital cost, fuel consumption and carbon dioxide emissions, it also makes possible substantially complete carbon capture from the overall process.

[0007] According to an embodiment, the present disclosure relates to an ATR system for the production of a hydrogen-rich product from a hydrocarbon feed. The ATR system includes: a hydrocarbon feed preheating section arranged to receive the hydrocarbon feed and apply thermal energy from electrical heating to the hydrocarbon feed to produce a preheated hydrocarbon feed; an autothermal reformer unit arranged to receive the preheated hydrocarbon feed and convert it to a syngas product; a shift conversion section arranged to receive the syngas product and convert it to a shifted syngas product; and a hydrogen separation unit arranged to receive the shifted syngas product and convert it to the hydrogen-rich product and an offgas product and where the system is not arranged to recycle the offgas product to a feed side of the autothermal reformer unit or to a feed side of the shift conversion section.

[0008] In another embodiment, the present disclosure relates to a process for producing a hydrogen-rich product from a hydrocarbon feed using the ATR system above. The process includes: i) supplying the hydrocarbon feed to the hydrocarbon feed preheating section and converting it to a preheated hydrocarbon feed; ii) supplying the preheated hydrocarbon feed to the autothermal reformer unit and converting it to a syngas product; iii) supplying the syngas product to the shift conversion section and converting it to the shifted syngas product; and iv) supplying the shifted syngas product to the hydrogen separation unit and converting it to a hydrogen-rich product and an offgas product.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] For a more complete understanding of the present disclosure and the advantages thereof, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts.

[0010] FIG. 1 schematically illustrates an exemplary autothermal reforming system according to embodiments of this disclosure.

DETAILED DESCRIPTION

[0011] It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed compositions, methods, and/or products may be implemented using any number of techniques, whether currently known or not yet in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated hereinbelow, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents.

[0012] While the following terms are believed to be well understood by one of ordinary skill in the art, the following definitions are set forth to facilitate explanation of the presently disclosed subject matter. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs.

[0013] As utilized herein, ‘renewable energy’ and ‘non-fossil based energy (ENF)’ includes energy derived from a sustainable energy source that is replaced rapidly by a natural, ongoing process, and nuclear energy. Accordingly, the terms ‘renewable energy’ and ‘non-fossil based energy ENF)’ refer to energy derived from a non-fossil fuel based energy source (e.g., energy not produced via the combustion of a fossil fuel such as coal or natural gas), while ‘non-renewable’ or ‘fossil based energy EF)’ is energy derived from a fossil fuel-based energy source (e.g., energy produced via the combustion of a fossil fuel). Fossil fuels are natural fuels, such as coal or gas, formed in the geological past from the remains of living organisms. Accordingly, as utilized herein, ‘renewable’ and ‘non-fossil based energy (ENF)’ include, without limitation, wind, solar power, water flow/movement, or biomass, that is not depleted when used, as opposed to ‘non-renewable’ energy from a source, such as fossil fuels, that is depleted when used. Renewable energy thus excludes fossil fuel based energy (EF) and includes biofuels.

[0014] As utilized herein, ‘non-carbon based energy ENC)’ is energy from a non-carbon based energy source (e.g., energy not produced via the combustion of a carbon-based fuel such as a hydrocarbon), while carbon based energy (Ec) is energy from a carbon-based energy source (e.g., energy produced via the combustion of a carbon-based fuel such as a hydrocarbon). Nuclear energy is considered herein a renewable, non-fossil (ENF) based energy and a non-carbon based energy (ENC). Carbon-based energy (Ec) can thus be renewable (e.g., non-fossil fuel based) or non- renewable (e.g., fossil fuel-based). For example, various carbon-based biofuels are herein considered renewable, carbon-based energy sources.

[0015] As utilized herein, ‘renewable electricity’ indicates electricity produced from a renewable energy source, while ‘non-renewable electricity’ is electricity produced from a non- renewable energy source. As utilized herein ‘non-carbon based electricity’ indicates electricity produced from a non-carbon based energy source, while ‘carbon-based electricity’ is electricity produced from a carbon-based energy source.

[0016] As utilized herein, ‘externally’ combusting a fuel refers to combusting a fuel outside of a reactor, e.g., in a fired preheater. Combustion as a part of the primary reaction (e.g., combustion which takes place with reforming in ATR) would not be considered ‘externally’ combusting.

[0017] The term “hydrogen-rich product” refers to a product stream containing at least 90 vol. % of hydrogen, or 95 vol. % or more hydrogen, for instance 98 vol. % or more hydrogen, with the balance being minor amounts of carbon containing compounds CF , CO, CO2, as well as N2, Ar.

[0018] The term “offgas product” refers to a product steam that contains significant quantities of a carbon oxide (i.e., a higher concentration of CO2 and/or CO than is present in ambient air). [0019] The term “carbon dioxide-rich product” refers to a product stream containing at least 90 vol. % of hydrogen, or 95 vol. % or more carbon dioxide, for instance 98 vol. % or more carbon dioxide, or 99.5 vol. % or more carbon dioxide.

[0020] The term “carbon dioxide-depleted product” refers to a product stream containing 1000 ppm or less carbon dioxide, for example, 500 ppm or less carbon dioxide, or 50 ppm or less carbon dioxide.

[0021] Although the majority of the above definitions are substantially as understood by those of skill in the art, one or more of the above definitions can be defined hereinabove in a manner differing from the meaning as ordinarily understood by those of skill in the art, due to the particular description herein of the presently disclosed subject matter.

[0022] According to embodiments of this disclosure, heat conventionally supplied as thermal energy by the combustion of a fuel (e.g., natural gas/fossil fuels) to preheat a hydrocarbon feed in an ATR system and process is replaced by electrical heating. Electrical heat, electrical heating, generating heat electrically, electrical heater apparatus, and the like refer to the conversion of electricity into thermal energy available to be applied to a fluid, for e.g., the hydrocarbon feed. Such electrical heating may include, without limitation, heating by impedance (e.g., where electricity flows through a conduit carrying the fluid to be heated), heating via ohmic heating, plasma, electric arc, radio frequency (RF), infrared (IR), UV, and/or microwaves, heating by passage over a resistively heated element, heating by radiation from an electrically-heated element, heating by induction (e.g., an oscillating magnetic field), heating by mechanical means (e.g., compression) driven by electricity, heating via a heat pump, heating by passing a relatively hot inert gas or another medium over tubes containing a fluid to be heated, where the hot inert gas or the another medium is heated electrically, or heating by some combination of the above.

[0023] In some embodiments, electricity for electrical heating as described herein may be produced from a renewable energy source such as wind, solar, geothermal, hydroelectric, nuclear, tide, wave, ocean thermal gradient power, pressure-retarded osmosis, or a combination thereof. In other embodiments, electricity for electrical heating may be produced from a non-carbon based energy source such as from hydrogen. In still other embodiments, some or all of the electricity is from a non-renewable and/or carbon-based source, such as, without limitation, combustion of hydrocarbons (e.g., renewable or non-renewable hydrocarbons), coal, or hydrogen derived from hydrocarbons (e.g., renewable or non-renewable hydrocarbons). [0024] With reference to Figure 1, an ATR system 1 may be considered to include one or more of the following sections or units for converting a hydrocarbon feed 5 into a hydrogen-rich product 8: a hydrocarbon feed preheating section 10, an autothermal reformer unit 20, a shift conversion section 30, and a hydrogen separation unit 40. It will be appreciated by those of skill in the art that this is a very simple schematic diagram and that an actual system may include additional sections and units of a standard type capable of heating, chilling, compressing, condensing, pumping, various types of separation and/or fractionation, as well as monitoring of pressures, temperatures, flows, and the like.

[0025] The hydrocarbon feed preheating section 10 can be arranged to receive the hydrocarbon feed 5 and apply thermal energy to the hydrocarbon feed to convert the hydrocarbon feed 5 to a preheated hydrocarbon feed 15. The hydrocarbon feed preheating section 10 may optionally be arranged to also remove undesirable components (e.g., sulfur) from the hydrocarbon feed 5, adjust the pressure of the hydrocarbon feed 5 and/or combine the hydrocarbon feed 5 with steam during conversion of the hydrocarbon feed 5 to a preheated hydrocarbon feed 15. The autothermal reformer unit 20 can be arranged to receive the preheated hydrocarbon feed 15 and an oxygen stream 21 and carry out syngas generation by the autothermal reforming of the preheated hydrocarbon feed 15 to produce a syngas product 25. A shift conversion section 30 can be arranged to receive the syngas product 25 and subject the syngas product 25 to water gas shifting to produce a shifted syngas product 35 containing additional hydrogen via the water gas shift reaction:

CO + H₂O <- — > H₂ + CO2.

A hydrogen separation unit 40 can be arranged to receive the shifted syngas product 35 and produce a hydrogen-rich product 8 and an offgas product 45.

[0026] As mentioned above, energy input into the hydrocarbon feed preheating section 10 (that is conventionally provided via a carbon based energy or a fossil fuel derived energy) is completely replaced by electrical heating. A benefit derived via the herein disclosed system and process may be a reduction in the greenhouse gas (GHG) emissions from the system and substantially complete carbon capture.

[0027] As noted hereinabove with reference to the embodiment of Figure 3, in embodiments, the ATR system 1 of this disclosure comprises a hydrocarbon feed preheating section 10. Hydrocarbons (e.g., natural gas) are introduced into the ATR system 1 via hydrocarbon feed 5. The hydrocarbon feed 5 is preheated by thermal energy from electrical heating in the hydrocarbon feed preheating section 10 to produce a preheated hydrocarbon feed 15. The hydrocarbon feed preheating section 10 may be configured to provide sufficient thermal energy via electrical heating to the hydrocarbon feed 5 to convert the hydrocarbon feed 5 to the preheated hydrocarbon feed 15 which may have a temperature of at least 350°C or at least 400°C, or at least 450°C, or at least 500°C, or at least 550°C, or greater than 600°C, or greater than 605°C.

[0028] In embodiments, a heat exchanger may be utilized to preheat the hydrocarbon feed 5 and it may comprise built-in heating elements. In embodiments, the hydrocarbon feed 5 may be preheated to a predetermined temperature by resistive heating (e.g., via electricity flowing through a wire in thermal but not necessarily electrical contact with a pipe carrying the hydrocarbon feed 5). In embodiments, the hydrocarbon feed 5 may be preheated by superheating dilution steam, where the dilution steam is heated by any of various methods of electrical heating. In other embodiments, steam is added to the hydrocarbon feed 5 as a diluent and not used for the purpose of preheating the hydrocarbon feed 5. In embodiments, the hydrocarbon feed 5 may be preheated by impedance (e.g., where electricity flows through the conduit carrying the feed). In embodiments, the hydrocarbon feed 5 may be heated directly by ohmic heating, or plasma, or an electric arc, or radio frequency (RF), or infrared (IR), or UV, and/or microwaves. In embodiments, the hydrocarbon feed 5 may be preheated by passage over a resistively heated element. In other embodiments, the hydrocarbon feed 5 may be preheated by induction (e.g., an oscillating magnetic field). In embodiments, the hydrocarbon feed 5 may be preheated by mechanical means driven by electricity. In embodiments, the hydrocarbon feed 5 may be preheated by a heat pump. In still other embodiments, the hydrocarbon feed 5 may be preheated by passing hot inert gas or another medium over the tubes, where the hot inert gas or the another medium is heated electrically (e.g., via any of the preceding methods, or the like.) In embodiments, the hydrocarbon feed 5 may be preheated by means of radiative panels that are heated electrically (e.g., via any of the preceding methods, or the like.) In embodiments, heating to the predetermined temperature can be effected by a combination of the above.

[0029] Elimination of the conventional fired preheater with electrical heating can significantly reduce the carbon footprint of the ATR system. The flue gas from the fired heater is normally emitted at a low pressure, thus the energy required for carbon dioxide removal from the low pressure flue gas is high. Furthermore, additional unit operations are needed to cool and purify the flue gas increasing capital cost. The present disclosure reduces energy and capital cost to produce a high purity hydrogen-rich product with in some embodiments at least 90% or more or at least 95% or more carbon capture. [0030] The hydrocarbon feed preheating section 10 may also be configured to adjust the pressure of the hydrocarbon feed. For example, an expander may be utilized to convert feed line pressure (e.g., from 500 psig to less than about 50 psig). In embodiments of this disclosure, the energy produced during this expansion can be captured as electricity, e.g., by driving a generator.

[0031] In embodiments where the hydrocarbon feed includes sulfur, it may be desirable to remove sulfur to reduce deactivation of the catalyst(s) used in subsequent steps. Sulfur removal can utilize catalytic hydrogenation to convert sulfur compounds in the hydrocarbon feed 5 to gaseous hydrogen sulfide. The gaseous hydrogen sulfide can then be adsorbed and removed by passing it through beds of, for example, zinc oxide, where it is converted to solid zinc sulfide.

[0032] As noted hereinabove with reference to the embodiment of Figure 1, the ATR system 1 also includes an autothermal reformer unit 20. The autothermal reformer unit 20 is configured to receive the preheated hydrocarbon feed 15 and an oxygen stream 21 and convert it to a syngas product 25. In embodiments, the preheated hydrocarbon feed 15 and oxygen stream 21 react in an oxidation section of the autothermal reformer unit and the reaction product then passes through a bed of reforming catalysts. The reaction can occur over a broad temperature range between about 350°-850° C. and at a pressure of from about 25-50 bar. The reaction is endothermic and the heat of reaction is provided by the combustion of oxygen in the oxygen stream 21 with the preheated hydrocarbon feed 15. The temperature of the syngas product 25 at the exit of the autothermal reformer unit 20 may be between about 900°-1100°C, or between about 950°-1100°C or between about 1000°-1075°C. The syngas product may include carbon monoxide, hydrogen, carbon dioxide, steam, residual methane and various other components, for example, nitrogen and argon.

[0033] In some embodiments, the autothermal reformer unit 20 may include an air separation apparatus (not shown) which is configured to receive an air stream and produce the oxygen stream 21. In embodiments, the oxygen stream 21 may be oxygen, a mixture of oxygen and steam, a mixture of oxygen, steam and argon, or oxygen-enriched air.

[0034] In embodiments, the ATR system 1 is without (i.e., absent) a steam methane reformer upstream of the autothermal reformer unit 20. Therefore, there is no primary reforming unit and no primary reforming step.

[0035] As noted above, the ATR system 1 of this disclosure further includes a shift conversion or ‘shifting’ section 30 configured to receive the syngas product 25 and convert it to a shifted syngas product 35. The shift conversion section 30 can include a high temperature shift reactor, a low temperature shift reactor, a first shift reactor, a final shift reactor, or any combination thereof. The shift conversion section 30 can include cooling upstream and/or downstream of the high temperature shift reactor, the low temperature shift reactor, or both, where the heat removed can be transferred either directly or indirectly to another process stream of the system.

[0036] After the syngas generation is complete in the autothermal reformer unit 20, the syngas product 25 is subjected to water gas shifting in the shift conversion section 30 to produce shifted syngas product 35 via the water gas shift (WGS) reaction according to the equation above. The shifting can be effected via any suitable methods known in the art. For example, shifting can comprise high temperature shift, low temperature shift, or both. In an embodiment, the syngas product 25 can be partially cooled at a first cooling step or unit(s) to produce a cooled reformer product which is then introduced into a high temperature shift reactor(s) where additional hydrogen is formed by shifting water and carbon monoxide to produce carbon dioxide and additional hydrogen via the water gas shift (WGS) reaction according to the equation above to provide a high temperature shifted stream. The high temperature shift may be performed at a temperature of between about 300°-450°C and at a pressure of between about 25-50 bar.

[0037] Shift conversion section 30 can further comprise cooling of the high temperature shifted stream in a second cooling step or unit(s) whereby the stream is cooled to provide cooled, high temperature shifted stream. Further completion of the shift reaction can be conducted by introducing cooled, high temperature shifted stream into a low temperature shift reactor. In embodiments, the low temperature shift can be performed at a temperature of between about 200°- 300°C and/or a pressure of between about 25-50 bar to provide a low temperature shifted product stream.

[0038] A third cooling step can be employed to reduce the temperature of the low temperature shifted product stream to provide a cooled, shifted syngas product 35. In embodiments, the shifted syngas product 35 may have a temperature suitable for feeding to the hydrogen purification unit 40, such as a temperature between ambient temperature and 100°C.

[0039] As noted above, the ATR system 1 further includes a hydrogen separation unit 40 configured to receive the shifted syngas product 35 and convert it to a hydrogen-rich product 8 and an offgas product 45. In some embodiments, the hydrogen purification unit 40 may include a cycling adsorber, a gas-permeable membrane, a cryogenic distillation apparatus, or other hydrogen separation unit known for separating/recovering hydrogen from the shifted syngas product 35. In embodiments, the cycling adsorber can be electrified. In embodiments, refrigeration for the cryogenic distillation can be electrified. In embodiments, the hydrogen-rich stream may be exported for further chemical use (e.g., to an ammonia plant, methanol plant, or a refinery) rather than burned to make heat.

[0040] In some embodiments, the hydrogen purification unit 40 includes a cycling adsorber, such as a pressure swing adsorption (PSA) unit and/or a temperature swing adsorption unit. In a PSA unit, the shifted syngas product 35 is passed under pressure for a period of time over at least one bed of a solid sorbent. The solid sorbent(s) can advantageously be selective (or at least relatively selective) for one or more components to be removed, usually regarded as contaminants in the shifted syngas product 35. Alternately, the sorbent may be (relatively) selective for one or more components desired to be isolated and kept (e.g., hydrogen) and not removed as contaminant(s). The skilled person should understand how to modify the disclosure herein to adjust for isolation of one or more desired compounds, as opposed to one or more contaminants (as presented below).

[0041] In an embodiment, a pressure swing cycle can include a feed step, at least one depressurization step, a purge step, and a repressurization step to prepare the adsorbent material for reintroduction of the shifted syngas product 35. The adsorption of the contaminant(s) can usually take place by physical adsorption, though (relatively) easily reversible chemical adsorption/absorption can be alternately contemplated. The sorbent can typically comprise (or consist essentially of) a porous solid such as activated carbon, alumina, silica, silica-alumina, or the like, that has an affinity for the contaminant. Zeolites can additionally or alternately be used in many applications since they may exhibit a significant degree of selectivity for certain contaminants by virtue of their controlled/predictable pore sizes. Normally, chemical reaction with the sorbent is not favored, in view of the increased difficulty of achieving desorption of species that have become chemically bound to the sorbent. However, chemisorption of a contaminant can result if the adsorbed material(s) may be effectively desorbed during the desorption portion of the cycle, e.g., by the use of higher temperatures coupled with the reduction in pressure. Following adsorption, the process swings to low pressure to release (“desorb”) the adsorbed contaminant(s).

[0042] In an embodiment, the shifted syngas product 35 delivered to the cycling adsorber unit for hydrogen recovery can have a total pressure of at least about 10 bar, for example at least about 15 bar, at least about 25 bar, at least about 40 bar, at least about 60 bar, or at least about 80 bar. Additionally or alternately, the shifted syngas product stream 35 delivered to the cycling adsorber unit can have a total pressure of about 120 bar or less, for example about 100 bar or less, about 80 bar or less, about 60bar or less, or about 40 bar or less. [0043] During typical operation of the cycling adsorber unit, a purge stream can also be used during a portion of the operation cycle. The pressure of the purge stream delivered to the cycling adsorber unit can be about 10 bar or less, for example about 8.5 bar or less, about 7 bar or less, about 5 bar or less, about 4 bar or less, or about 3 bar or less.

[0044] The pressure of the hydrogen-rich product 8 exiting the cycling adsorber unit can typically be similar to, but usually slightly lower than, the input pressure of the shifted syngas product stream 35. The pressure of the hydrogen-rich product 8 can differ from the pressure of the input shifted syngas product stream 35 by about 4 bar or less, for example about 2.5 bar or less, about 1 bar or less, or about 0.5 bar or less. Additionally or alternately, the pressure of the hydrogen-rich product 8 can be at least about 90% of the input shifted syngas product stream pressure, for example at least about 95%, at least about 98%, or at least about 99%. The hydrogen content (or purity) of the hydrogen-rich product 8 can be at least about 90% by volume, or at least about 95.0% by volume, or at least about 99.0% by volume, or at least about 99.1% by volume, or at least about 99.3% by volume, or at least about 99.5% by volume. Relative to the shifted syngas product 35, the hydrogen-rich product 8 can include at least about 80% by volume of the hydrogen from the input shifted syngas product 35, for example at least about 85% by volume or at least about 90% by volume.

[0045] In other embodiments, hydrogen-permeable membranes with good hydrogen/carbon dioxide selectivity can alternatively be used. Examples of hydrogen-selective membranes for use in the ATR system and process typically comprise organic polymeric materials. Any organic polymer membrane with suitable performance properties may be used. Examples of such membranes include the polybenzimidazole (PBI)-based membranes and polyimide-based membranes. Other hydrogenselective membrane materials include polyamides, polyurethanes, polyureas, and polybenzoxazoles, by way of example and not by way of limitation.

[0046] The hydrogen purification unit 40 can also produce an offgas product 45. The offgas product 45 can include the reduced pressure flows produced during the portions of the cycle that regenerate the adsorbent. The pressure of the offgas product 45 can be about 10 bar or less, for example about 7 bar or less, about 5 bar or less, about 4 bar or less, or about 3 bar or less.

[0047] The offgas product 45 is not pure carbon dioxide and it’s desirable to recover and/or capture carbon dioxide from the offgas product 45 for sequestration or some other purpose. Various carbon dioxide recovery units and processes may be used to separate carbon dioxide from the offgas product 45 to produce a carbon dioxide-rich product. One option can involve passing the offgas product 45 through an absorbent system, such as an amine absorbent system. Suitable amines can include piperazines and/or ethanolamines. Various known/conventional methods for using amines to extract carbon dioxide can be used in conjunction with the inventive systems and methods described herein.

[0048] One example of an amine adsorbent system for separating carbon dioxide from the offgas product 45 to produce a carbon-dioxide rich product is a pair of columns. A first column can be set up for effective contacting of the offgas product 45 with an amine sol vent/ab sorbent for the carbon dioxide present in the offgas product 45. The offgas product 45 can advantageously be passed through the column in a counter-current manner relative to the amine absorbent. The output from the first column can thus be a gas phase product with a reduced carbon dioxide content and typically a liquid absorbent with an increased carbon dioxide content. Optionally, the column can include contacting elements to increase the interaction between the gas flow and the liquid absorbent within the column. The contacting elements can be, for example, trays or packing material. Optionally, a wash region can be included at the top of the column to remove any absorbent that becomes entrained in the gas phase flow.

[0049] The second column can advantageously be used to regenerate the absorbent resulting in the carbon dioxide-rich product. In the second column, the liquid absorbent containing the carbon dioxide can be passed down through the second column. The second column may also contain contacting elements. The pressure in the second column can be lower than the first column, resulting in some release of the carbon dioxide due to the lower pressure. Carbon dioxide remaining in the absorbent at the bottom of the column can be removed by heating the absorbent. This can result in action similar to a distillation column, where the absorbent and carbon dioxide can form a vapor that can travel up in the column. As the vapor cools, the absorbent can fall back down in the column as a liquid, leaving behind the gas phase carbon dioxide. The carbon dioxide-rich product stream can be removed from the top of the second column.

[0050] By using an amine adsorbent unit (or another type of carbon dioxide recovery unit), carbon dioxide can be separated from the offgas product 45 to form the carbon dioxide-rich product and a carbon di oxi de-depl eted product. The offgas product 45 sent to the carbon dioxide recovery unit can have a carbon dioxide content of about 75 vol % or less, for example about 70 vol % or less, about 65% or less, or about 60 vol % or less. Additionally or alternately, the offgas product 45 sent to the carbon dioxide recovery unit can have a carbon dioxide content of at least about 50 vol %, for example at least about 60 vol % or at least about 65 vol %. [0051] Other options for recovering carbon dioxide from the offgas product 45 can include a membrane separation system that contains membranes selective to carbon dioxide over hydrogen, carbon monoxide, and methane. The preferred form is a composite membrane. Modem composite membranes typically comprise a highly permeable, but relatively non- selective, support membrane that provides mechanical strength, coated with a thin selective layer of another material that is primarily responsible for the separation properties. Typically, but not necessarily, such a composite membrane is made by solution-casting the support membrane, then solution-coating the selective layer. Preparation techniques for making composite membranes of this type are well-known. The membranes may be manufactured as flat sheets or as fibers and housed in any convenient module form, including spiral-wound modules, plate-and-frame modules, and potted hollow fiber modules.

[0052] In another embodiment, the carbon dioxide may be separated/recovered from the offgas product 45 by condensation against a cold refrigerant. In a variant, the offgas product may be compressed sufficiently, typically from 800 psig to 1000 psig to enable carbon dioxide condensation against cooling water and thus avoiding the need for refrigeration. Recovery of carbon dioxide from a gas stream by condensation is known in the art and will therefore be understood by the skilled man. For example, its known to use a distillation column in series with a carbon dioxide specific membrane for carbon dioxide recovery, whereby a part of the carbon dioxide exiting the column overheads is recovered using the membrane and, after being compressed, is recycled to the column feed stream.

[0053] The system used to recover the carbon dioxide-rich product by condensation generally includes a refrigeration unit, which provides the refrigerant against which the carbon dioxide can be condensed. The apparatus may also comprise one or more of the following: a chiller to remove most of the water vapor present; a water collection and removal facility; driers to dry the gas; and one or more heat exchangers.

[0054] The liquid carbon dioxide would usually be produced at pressures of typically 20-40 bar, e.g., 35-40 bar, but this pressure could be readily increased to higher pressures if needed by pumping alone, without the need for expensive additional compression facilities. Lower pressures could be used, but as the pressure is decreased so does the carbon dioxide condensing temperature; the refrigeration energy requirement and cost thus increase and ultimately become prohibitive. In the event that the carbon dioxide is required in gaseous form, once the liquid carbon dioxide has been condensed from the gas stream, the liquid carbon dioxide is subsequently vaporized. [0055] In still other embodiments, carbon dioxide may be recovered from the shifted syngas product 45 prior to treatment in the hydrogen purification unit 40. In this embodiment, the shifted syngas product 35 is first passed through a carbon dioxide recovery unit to produce the carbon dioxide-rich product and a stream containing a reduced amount of carbon dioxide. The stream containing a reduced amount of carbon dioxide is then passed through the hydrogen purification unit 40 to produce the hydrogen-rich product and the offgas product.

[0056] While various embodiments have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the disclosure. The embodiments described herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the subject matter disclosed herein are possible and are within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, RL and an upper limit, Ru is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=RL+k*(Ru-Rr), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, ie., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, ... 50 percent, 51 percent, 52 percent, ... , 95 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term "optionally" with respect to any element of a claim is intended to mean that the subject element is required, or alternatively, is not required. Both alternatives are intended to be within the scope of the claim. Use of broader terms such as comprises, includes, having, etc. should be understood to provide support for narrower terms such as consisting of, consisting essentially of, comprised substantially of, etc.

[0057] Accordingly, the scope of protection is not limited by the description set out above but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated into the specification as an embodiment of the present disclosure. Thus, the claims are a further description and are an addition to the embodiments of the present disclosure. The discussion of a reference is not an admission that it is prior art to the present disclosure, especially any reference that may have a publication date after the priority date of this application. The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated by reference, to the extent that they provide exemplary, procedural, or other details supplementary to those set forth herein.

Claims

1. An autothermal reformer (ATR) system for the production of a hydrogen-rich stream from a hydrocarbon feed, the system comprising a hydrocarbon feed preheating section arranged to receive the hydrocarbon feed and apply thermal energy from electrical heating to the hydrocarbon feed to produce a preheated hydrocarbon feed; an autothermal reformer unit arranged to receive the preheated hydrocarbon feed and convert it to a syngas product; a shift conversion section arranged to receive the syngas product and convert it to a shifted syngas product; and a hydrogen purification unit arranged to receive the shifted syngas product and convert it to a hydrogen-rich product and an offgas product comprising carbon dioxide wherein the system is not arranged to recycle the offgas stream to a feed side of the autothermal reformer or to a feed side of the shift conversion section.

2. The ATR system of claim 1, further comprising a carbon dioxide recovery unit arranged to receive the offgas product and separate carbon dioxide from the offgas product to produce a carbon dioxide-rich product.

3. The ATR system of claim 1, wherein the electrical heating includes heating by passage of the hydrocarbon feed over a resistively heated element,

4. The ATR system of claim 1, wherein the electrical heating includes heating by induction.

5. The ATR system of claim 1, the autothermal reformer unit comprises an air separation apparatus arranged to receive an air stream and produce the oxygen stream.

6. The ATR system of claim 1, wherein the system is absent a steam methane reformer upstream of the autothermal reformer unit.

7. The ATR system of claim 1, wherein the hydrogen purification unit comprises a pressure swing adsorption unit.

8. A process for producing a hydrogen-rich stream from a hydrocarbon feed, the process comprising: i) providing a system according to claim 1; ii) supplying the hydrocarbon feed to the hydrocarbon feed preheating section and converting it to a preheated hydrocarbon feed; iii) supplying the preheated hydrocarbon feed to the autothermal reformer unit and converting it to a syngas product; iv) supplying the syngas product to the shift conversion section and converting it to a shifted syngas product; and v) supplying the shifted syngas product to a hydrogen purification unit and converting it to a hydrogen-rich product and an offgas product comprising carbon dioxide.

9. The process of claim 8, wherein the process further comprises supplying the offgas product to a carbon dioxide recovery unit and separating carbon dioxide from the offgas product to produce a carbon dioxide-rich product and a carbon dioxide-depleted product.

10. The process of claim 9, wherein the carbon recovery unit comprises an amine adsorbent system.

11. The process of claim 8, wherein the hydrogen purification unit comprises a pressure swing adsorption unit.