Integrated fischer-tropsch processes

Abstract

The present disclosure relates generally to a process for preparing hydrocarbons. The process comprises contacting a shift feed stream comprising carbon dioxide and hydrogen with a reverse water-gas shift catalyst under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water; providing a Fischer-Tropsch feed stream comprising at least a portion of the carbon monoxide, hydrogen, and carbon dioxide from the shift product stream; contacting the Fischer-Tropsch feed stream with an iron-based Fischer-Tropsch catalyst, in the substantial absence of a cobalt-based Fischer-Tropsch catalyst, to form an Fischer-Tropsch product stream comprising C5+ hydrocarbons, light hydrocarbons, water and carbon dioxide; and separating the Fischer-Tropsch product stream to provide a first separated product stream.

Description

INTEGRATED FISCHER-TROPSCH PROCESSESCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority U.S. provisional application number 63 / 616,376, filed December 29, 2023 and European Patent application number 24166559.5, filed March 26, 2024, each of which is incorporated by reference herein in its entirety.BACKGROUND OF THE DISCLOSURE1 Field

[0002] The present disclosure relates processes for performing Fischer-Tropsch reactions that are integrated with reverse water-gas shift processes.2. Technical Background

[0003] The iron-catalyzed Fischer Tropsch (FT) process converts syngas (CO / H2) to long chain hydrocarbon products that can be upgraded (cracking / hydrotreating) to make fuels, base oils, lubricants and other products. While iron-based catalysts have advantages over cobalt-based FT catalysts in terms of economics (lower cost of Fe vs Co) and sustainability (resource scarcity and mining of cobalt oxides), iron-based catalysts generally exhibit a high water-gas shift activity, which leads to high CO2 yields. This can be useful for syngas with low H2 / CO ratios from coal or biomass, as the water-gas shift reaction of CO to CO2 produces hydrogen that can increase the H2 / CO ratio. However, in terms of C5+ productivity, the water-gas shift activity decreases the carbon recovery from CO into C5+ hydrocarbon, the main product of interest, due to this conversion of CO into CO2.

[0004] CO2 is present in the in Earth’s atmosphere in low levels, but its concentration has been rising consistently for decades. The increased levels of CO2 traps additional heat near the Earth's surface, causing temperatures to rise and leading to climate change. Rather than emitting CO2 to the atmosphere, the refineries and petrochemical industry, like carbonintensive industries such as cement and steelmaking, have begun capturing the CO2 and sequestering the CO2, e.g., in ocean beds, which is an expensive undertaking

[0005] The present inventors note that CO2 can be considered as a useful carbon resource. Producing hydrocarbon fuels from captured CO2 emissions would hence allow achievement of CO2 circularity, especially given the near-unlimited CO2 supply when considering direct air capture. Furthermore, fuels produced via this route from CO2 can be considered free of sulfur and nitrogen contaminants and could be used to power heavy transport such as ships and planes which are difficult to electrify.

[0006] There remains a need in the art for improved Fischer-Tropsch methods that can efficiently use carbon dioxide as a feed.SUMMARY

[0007] In one aspect, the present disclosure provides for a process for preparing hydrocarbons, the process comprising: contacting a shift feed stream comprising carbon dioxide and hydrogen with a reverse water-gas shift (rWGS) catalyst under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water; providing a Fischer-Tropsch (FT) feed stream comprising at least a portion of the carbon monoxide, hydrogen, and carbon dioxide from the shift product stream, the FT feed stream comprising at least 5 mol% carbon dioxide, the FT feed stream having a molar ratio of carbon dioxide to carbon monoxide of at least 2, e.g., at least 2.5 or at least 3; contacting the FT feed stream with an iron-based FT catalyst, in the substantial absence of a cobalt-based FT catalyst, to form an FT product stream comprising C5+ hydrocarbons, light hydrocarbons, water and carbon dioxide; and separating the FT product stream to provide a first separated product stream comprising at least 80 wt% of the C5+ hydrocarbons and at least 80 wt% of the water of the FT product stream.

[0008] In particular embodiments as described herein, the contacting of the shift feed stream with the rWGS catalyst is performed in a first reactor bed, and the contacting of the FT feed stream with the iron-based FT catalyst is performed in a second reactor bed.BRIEF DESCRIPTION OF FIGURES

[0009] The accompanying drawings are included to provide a further understanding of the methods of the disclosure, and are incorporated in and constitute a part of this specification. The drawings are not necessarily to scale, and sizes of various elements may be distorted for clarity. The drawings illustrate one or more embodiment(s) of the disclosure and together with the description serve to explain the principles and operation of the disclosure.

[0010] FIG. 1 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.

[0011] FIG. 2 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.

[0012] FIG. 3 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.

[0013] FIG. 4 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.

[0014] FIG. 5 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.

[0015] FIG. 6 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.

[0016] FIG. 7 is a schematic of a process for performing an integrated Fischer-Tropsch process as described herein.DETAILED DESCRIPTION

[0017] The reverse water-gas shift reaction (rWGS) is an advantageous route to obtain carbon monoxide from carbon dioxide for further chemical processing. The rWGS is merely the reverse reaction of the water-gas shift reaction, converting carbon dioxide and hydrogen to carbon monoxide and water, as shown in Equation (1).AHO298= 42.1 kJmol-1Eq. (1)This can be used, for example, to modify the CO:H2ratio of a gas mixture for further processing. Water-gas shift processes are equilibrium processes; above, the process is shown in the so-called “reverse” direction but the person of ordinary skill in the art will appreciate that the direction of the reaction will depend on various factors as the reaction temperature and the relative amounts of various reactants / products. The carbon monoxide and hydrogen so formed is a valuable feedstock for a number of chemical processes, for example, the well-known Fischer-Tropsch (FT) process, shown in Equation (2).CO + 2 H2[-CH2-] + H2O AHO298= -152 kJmol-1Eq. (2)

[0018] However, the rWGS reaction is not favored in all circumstances. For example, a competing reaction is the Sabatier reaction (Equation (3)), which decreases carbon monoxide yield in favor of methane production, which is not an active feedstock for FT.AHO298= -165 kJmol-1Eq. (3)The strongly exothermic Sabatier reaction is thermodynamically favored over the endothermic rWGS reaction at lower reaction temperatures. As such, minimizing the methanation during rWGS, especially at low temperatures, can become a significant challenge.

[0019] Similarly, the carbon monoxide product from rWGS can be hydrogenated to methane, as shown in Equation (4).HO298= -206.5 kjmol-1Eq. (4)Hydrogenation of carbon monoxide to methane is also an exothermic reaction, so it too is favored at lower temperatures. The stoichiometry of the reaction requires at least a 3:1 ratio of hydrogen to carbon monoxide. This means that performing the rWGS reaction with a large excess of hydrogen to drive the equilibrium toward carbon monoxide (see Equation (1)) is not always ideal because it runs the risk of hydrogenating the carbon monoxide product to form methane.

[0020] Coupled with Equations (3) and (4), further undesirable side reactions can occur. These side reactions can form undesirable carbon deposits on the surface of catalysts used to promote rWGS. Examples of these carbon-producing side reactions are shown in Equations (5), (6), and (7). All three of these reactions are endothermic and are favored at higher temperatures, just like the rWGS reaction.CO + H2-> C + H2O AH°298 = 131 kjmol-1Eq. (5)CH4-> 2H2+ C AH°298= 75 kJmol-1Eq. (6)AH°298 = 171 kjmol-1Eq. (7)Accordingly, because the carbon-producing side reactions (Equations (5)-(7)) are also endothermic and are favored at higher temperatures, operation at higher temperatures to favor the desired carbon monoxide product can severely impact catalyst lifetime through the deposition of carbon.

[0021] Thus, the rWGS reaction reacts carbon dioxide with hydrogen to form carbon monoxide and water and can be useful in providing a feedstock containing carbon monoxide and hydrogen - often called “synthesis gas” - for use in processes such as the FT processes. However, the Sabatier reaction, carbon monoxide methanation, and carbon- producing side reactions can interfere with the rWGS reaction. The Sabatier reaction and carbon monoxide methanation are exothermic and favored at lower temperatures, while the rWGS and carbon-producing side reactions are endothermic and favored at higher temperatures. Accordingly, there remains a need for improved rWGS processes to be integrated with the FT processes.

[0022] The present inventors have noted that the reverse water-gas shift reaction can be used to convert carbon dioxide to carbon monoxide, which can be used in Fischer-Tropsch processes. The present inventors have also noted the desirability of the use of iron-basedcatalysts for the Fischer-Tropsch reaction, but noted further that iron-based Fischer-Tropsch catalysts themselves can have significant water-gas shift activity, which can undesirably convert the carbon monoxide made in the reverse water-gas shift stage back to carbon dioxide.

[0023] To address this problem, the present inventors provide here a process in which the feed to the Fischer-Tropsch reaction has significantly more carbon dioxide than carbon monoxide. As the water-gas shift reaction is a reversible process, maintaining a high ratio of carbon dioxide to carbon monoxide at the iron-based Fischer-Tropsch catalyst can suppress the forward water-gas shift and enhance the reverse water-gas shift, thereby allowing the carbon monoxide formed in the reverse water-gas shift stage to be converted to desirable products. Under such conditions, in some cases the shift activity of the iron-based catalyst itself can form additional carbon monoxide under the FT reaction conditions.

[0024] Accordingly, in one aspect, the present disclosure provides a process for preparing hydrocarbons. The process includes contacting a shift feed stream comprising carbon dioxide and hydrogen with an rWGS catalyst under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water; providing an FT feed stream comprising at least a portion of the carbon monoxide, hydrogen, and carbon dioxide from the shift product stream, the FT feed stream comprising at least 5 mol% carbon dioxide, the FT feed stream having a molar ratio of carbon dioxide to carbon monoxide of at least 2, e.g., at least 2.5 or at least 3; contacting the FT feed stream with an iron-based FT catalyst, in the substantial absence of a cobalt-based FT catalyst, to form an FT product stream comprising C5+ hydrocarbons, light hydrocarbons, water and carbon dioxide; and separating the FT product stream to provide a first separated product stream comprising at least 80 wt% of the C5+ hydrocarbons and at least 80 wt% of the water of the FT product stream.

[0025] As described herein, the process further includes contacting a shift feed stream comprising carbon dioxide and hydrogen with an rWGS catalyst under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water.

[0026] Reverse Water-Gas Shift Catalysts

[0027] The rWGS catalysts suitable for use in the process as described herein are not particularly limited, and the person of ordinary skill in the art would be able to select an appropriate rWGS catalyst. For example, the person of ordinary skill in the art would be able to select a catalyst as described in Daza et al., “CO2 conversion by reverse water gas shiftcatalysis: comparison of catalysts, mechanisms and their consequences for CO2 conversion to liquid fuels,” RSC Adv., 2016, 6, 49675-49691; Zhu et al., “Catalytic Reduction of CO2 to CO via Reverse Water Gas Shift Reaction: Recent Advances in the Design of Active and Selective Supported Metal Catalyst,” Transaction of Tianjin University, 2020, 26, 172-187; and Chen et al., “Recent Advances in Supported Metal Catalysts and Oxide Catalyst for the Reverse Water-Gas Shift Reaction,” Front. Chem., 2020, 8, 709. These catalysts include rWGS active metals. For example, such active metals may be selected from copper, platinum, palladium, rhodium, rhenium, ruthenium, nickel, gold, iridium, or combinations thereof.

[0028] In various embodiments as otherwise described herein, the rWGS catalyst is a copper-based catalyst. In various embodiments as otherwise described herein, the rWGS catalyst comprises a transition metal selected from manganese, zinc, gallium, indium, lanthanum, titanium, niobium, vanadium, zirconium, platinum, palladium, gold, and nickel.

[0029] The rWGS catalysts suitable for use in the process as described herein can be in a variety of forms and are not particularly limited. The person of ordinary skill in the art will be familiar with a variety of rWGS catalysts suitable for use in the processes described herein. For example, the rWGS catalyst may be a supported or unsupported catalyst. While the form of the catalyst is not particularly limited, in various desirable embodiments, the rWGS catalyst is a supported rWGS catalyst comprising a support that is a cerium oxide support, a titanium oxide support, aluminum oxide support, a zinc oxide support, a zirconium oxide support, or a mixed oxide support comprising a mixture of two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide and zirconium oxide; a metal selected from at least one of manganese, copper, gallium, indium, lanthanum, titanium, niobium, vanadium, and zirconium, present in an amount in the range of 0.5 to 20 wt% of the catalyst, based on the total weight of the catalyst; and optionally, at least one of platinum, palladium, gold, and nickel, present in an amount in the range of 0.05 to 10 wt% of the catalyst, based on the total weight of the catalyst. Suitable catalysts have been described in International Patent Application No. PCT / CN2022 / 102723, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102660, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102685, filed June 30, 2022, International Patent Application No.PCT / CN2022 / 102763, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102976, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102812, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102630, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102630, filed June 30, 2022, International Patent Application No. PCT / CN2022 / 102799, filed June 30, 2022, International Patent Application No.PCT / IB2023 / 056800, filed June 29, 2023, International Patent Application No. PCT / IB2023 / 056802, filed June 29, 2023, International Patent Application No. PCT / IB2023 / 056803, filed June 29, 2023, International Patent Application No. PCT / CN2023 / 104014, filed June 29, 2023, and International Patent Application No. PCT / CN2023 / 103835, filed June 29, 2023, each of which is hereby incorporated by reference in its entirety.

[0030] In various embodiments as otherwise described herein, the present disclosure provides a supported rWGS catalyst comprising a support that is a cerium oxide support, a titanium oxide support, aluminum oxide support, a zinc oxide support, a zirconium oxide support, or a mixed oxide support comprising a mixture of two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide; a metal selected from at least one of manganese, copper, gallium, indium, lanthanum, titanium, niobium, vanadium, and zirconium, present in an amount in the range of 0.5 to 20 wt% of the catalyst, based on the total weight of the catalyst; and at least one of platinum, palladium, gold, and nickel, present in an amount in the range of 0.05 to 10 wt% of the catalyst, based on the total weight of the catalyst.

[0031] In various embodiments as otherwise described herein, the support makes up at least 70 wt%, e.g., at least 75 wt%, or 80 wt%, or 85 wt%, or 90 wt% of the catalyst on an oxide basis.

[0032] In various embodiments as otherwise described herein, the support is a cerium oxide support. As used herein, a “cerium oxide” support is a support that presents at least a surface layer (e.g., 50 microns in thickness) that is at least 50 wt% cerium oxide, on an oxide basis. In various embodiments of the disclosure as described herein, at least a surface layer of the cerium oxide support includes at least 60 wt% cerium oxide, e.g., at least 70 wt% cerium oxide, or at least 80 wt% cerium oxide. In some such embodiments, at least a surface layer of the cerium oxide support includes at least 90 wt% cerium oxide. For example, in some embodiments, at least a surface layer of the cerium oxide support includes at least 95 wt% cerium oxide or at least 98 wt% cerium oxide. In various examples, the cerium oxide support contains cerium oxide substantially throughout, e.g., at least 50 wt% of the cerium oxide support is cerium oxide, on an oxide basis. For example, in various embodiments, the cerium oxide support includes at least 60 wt% cerium oxide, e.g., at least 70 wt% cerium oxide, or at least 80 wt% cerium oxide. In various embodiments, the cerium oxide support includes at least 90 wt% cerium oxide, e.g., at least 95 wt% cerium oxide, or at least 98 wt% cerium oxide. In some embodiments, the cerium oxide support may further include additional metals or metal oxides.

[0033] In various embodiments as otherwise described herein, the support is a titanium oxide support. As used herein, a “titanium oxide” support is a support that presents at least a surface layer (e.g., 50 microns in thickness) that is at least 50 wt% titanium oxide, on an oxide basis. In various embodiments of the disclosure as described herein, at least a surface layer of the titanium oxide support includes at least 60 wt% titanium oxide, e.g., at least 70 wt% titanium oxide, or at least 80 wt% titanium oxide. In some such embodiments, at least a surface layer of the titanium oxide support includes at least 90 wt% titanium oxide. For example, in some embodiments, at least a surface layer of the titanium oxide support includes at least 95 wt% titanium oxide or at least 98 wt% titanium oxide. In various examples, the titanium oxide support contains titanium oxide substantially throughout, e.g., at least 50 wt% of the titanium oxide support is titanium oxide, on an oxide basis. For example, in various embodiments, the titanium oxide support includes at least 60 wt% titanium oxide, e.g., at least 70 wt% titanium oxide, or at least 80 wt% titanium oxide. In various embodiments, the titanium oxide support includes at least 90 wt% titanium oxide, e.g., at least 95 wt% titanium oxide, or at least 98 wt% titanium oxide. In some embodiments, the titanium oxide support may further include additional metals or metal oxides.

[0034] In various embodiments as otherwise described herein, the support is an aluminum oxide support. As used herein, an “aluminum oxide” support is a support that presents at least a surface layer (e.g., 50 microns in thickness) that is at least 50 wt% aluminum oxide, on an oxide basis. In various embodiments of the disclosure as described herein, at least a surface layer of the aluminum oxide support includes at least 60 wt% aluminum oxide, e.g., at least 70 wt% aluminum oxide, or at least 80 wt% aluminum oxide. In some such embodiments, at least a surface layer of the aluminum oxide support includes at least 90 wt% aluminum oxide. For example, in some embodiments, at least a surface layer of the aluminum oxide support includes at least 95 wt% aluminum oxide or at least 98 wt% aluminum oxide. In various examples, the aluminum oxide support contains aluminum oxide substantially throughout, e.g., at least 50 wt% of the aluminum oxide support is aluminum oxide, on an oxide basis. For example, in various embodiments, the aluminum oxide support includes at least 60 wt% aluminum oxide, e.g., at least 70 wt% aluminum oxide, or at least 80 wt% aluminum oxide. In various embodiments, the aluminum oxide support includes at least 90 wt% aluminum oxide, e.g., at least 95 wt% aluminum oxide, or at least 98 wt% aluminum oxide. In some embodiments, the aluminum oxide support may further include additional metals or metal oxides.

[0035] In various embodiments as otherwise described herein, the support is a zinc oxide support. As used herein, a “zinc oxide” support is a support that presents at least asurface layer (e.g., 50 microns in thickness) that is at least 50 wt% zinc oxide, on an oxide basis. In various embodiments of the disclosure as described herein, at least a surface layer of the zinc oxide support includes at least 60 wt% zinc oxide, e.g., at least 70 wt% zinc oxide, or at least 80 wt% zinc oxide. In some such embodiments, at least a surface layer of the zinc oxide support includes at least 90 wt% zinc oxide. For example, in some embodiments, at least a surface layer of the zinc oxide support includes at least 95 wt% zinc oxide or at least 98 wt% zinc oxide. In various examples, the zinc oxide support contains zinc oxide substantially throughout, e.g., at least 50 wt% of the zinc oxide support is zinc oxide, on an oxide basis. For example, in various embodiments, the zinc oxide support includes at least 60 wt% zinc oxide, e.g., at least 70 wt% zinc oxide, or at least 80 wt% zinc oxide. In various embodiments, the zinc oxide support includes at least 90 wt% zinc oxide, e.g., at least 95 wt% zinc oxide, or at least 98 wt% zinc oxide. In some embodiments, the zinc oxide support may further include additional metals or metal oxides.

[0036] In various embodiments as otherwise described herein, the support is a zirconium oxide support. As used herein, a “zirconium oxide” support is a support that presents at least a surface layer (e.g., 50 microns in thickness) that is at least 50 wt% zirconium oxide, on an oxide basis. In various embodiments of the disclosure as described herein, at least a surface layer of the zirconium oxide support includes at least 60 wt% zirconium oxide, e.g., at least 70 wt% zirconium oxide, or at least 80 wt% zirconium oxide. In some such embodiments, at least a surface layer of the zirconium oxide support includes at least 90 wt% zirconium oxide. For example, in some embodiments, at least a surface layer of the zirconium oxide support includes at least 95 wt% zirconium oxide or at least 98 wt% zirconium oxide. In various examples, the zirconium oxide support contains zirconium oxide substantially throughout, e.g., at least 50 wt% of the zirconium oxide support is zirconium oxide, on an oxide basis. For example, in various embodiments, the zirconium oxide support includes at least 60 wt% zirconium oxide, e.g., at least 70 wt% zirconium oxide, or at least 80 wt% zirconium oxide. In various embodiments, the zirconium oxide support includes at least 90 wt% zirconium oxide, e.g., at least 95 wt% zirconium oxide, or at least 98 wt% zirconium oxide. In some embodiments, the zirconium oxide support may further include additional metals or metal oxides.

[0037] In various embodiments as otherwise described herein, the support is a mixed oxide support. These can be provided, for example, by admixture of multiple of the oxides above and formation into a support that includes both. For example, in some embodiments, the mixed oxide support is a mixture of two or more metal oxides, such as cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. In some embodiments, at least a surface layer of the support includes at least 50 wt% total of two or more of ceriumoxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide, on an oxide basis. In some embodiments, at least a surface layer of the mixed oxide support includes at least 60 wt% total, e.g., at least 70 wt%, or at least 80 wt% of two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. In some embodiments, at least a surface layer of the mixed oxide support includes at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of two or more cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. In various examples, the mixed oxide support contains the oxides substantially throughout, e.g., at least 50 wt% of the mixed oxide support is two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. In various embodiments, the mixed oxide support includes at least 60 wt% total, e.g., at least 70 wt%, or at least 80 wt% of two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. In various embodiments, the mixed oxide support includes at least 90 wt% total, e.g., at least 95 wt%, or at least 98 wt% of two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide. In some embodiments, the mixed oxide support may further include additional metals or metal oxides.

[0038] The present inventors have found that cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide can provide good performance in the absence of substantial amounts of other metals in the support. For example, in various embodiments as otherwise described herein, the support does not include additional metals in a total amount of additional metals in excess of 2 wt%, e.g., in excess of 1 wt% or in excess of 0.5 wt%, on an oxide basis.

[0039] However, the inventors have noted that in many cases performance can be desirably affected by the inclusion of other metals in the support. Accordingly, in other embodiments as otherwise described herein, the support includes at least one additional metal. In various embodiments, the total amount of the at least one additional metal is in the range of 0.5-20 wt%, e.g., 1-20 wt%, or 2-20 wt%, or 0.5-15 wt%, or 1-15 wt%, or 2-15 wt%, or 0.5-10 wt%, or 1-10 wt%, or 2-10 wt%, or 0.5-5 wt%, or 1-5 wt%, on an oxide basis.

[0040] Supports suitable for use herein can be provided with a range of pore volumes. The person of ordinary skill in the art will select a pore volume appropriate for a desired catalytic process. For example, in various embodiments as otherwise described herein, the pore volume is at least 0.05 mL / g, e.g., at least 0.1 mL / g. In various embodiments as otherwise described herein, the pore volume is at most 1.5 mL / g, e.g., at most 1 mL / g. In various embodiments of the present disclosure as described herein, the pore volume is in the range of 0.05-1.5 mL / g, e.g., 0.1 mL / g to 1 mL / g. Pore volumes are measured by mercury porosimetry, for example, as measured according to ASTM D4284-12.

[0041] As described above, the supported rWGS catalysts as described herein include a metal selected from at least one of manganese, copper, zinc, gallium, indium, lanthanum, titanium, niobium, vanadium, and zirconium. The present inventors have determined that inclusion of the metal(s) in the catalyst can provide improved CO selectivity for the rWGS reaction. For the purposes of this disclosure, the amount of metal present is calculated as a weight percentage of metal atoms in the catalyst based on the total weight of the catalyst, despite the form in which that metal may be present. The metal may be present in the catalyst in a variety of forms; most commonly, metal is principally present as metal oxide, metal, or a combination thereof.

[0042] In various embodiments as otherwise described herein, manganese is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, manganese is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, manganese is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt% or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, manganese is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, manganese is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0043] In various embodiments as otherwise described herein, copper is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, copper is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, copper is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, copper is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, copper is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0044] In various embodiments as otherwise described herein, zinc is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, zinc is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, zinc is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, zinc is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, zinc is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0045] In various embodiments as otherwise described herein, gallium is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, gallium is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, gallium is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, gallium is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, gallium is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0046] In various embodiments as otherwise described herein, indium is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, indium is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, indium is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, indium is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosureas described herein, indium is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0047] In various embodiments as otherwise described herein, lanthanum is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, lanthanum is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, lanthanum is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, lanthanum is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, lanthanum is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0048] In various embodiments as otherwise described herein, titanium is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, titanium is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, titanium is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, titanium is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, titanium is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0049] In various embodiments as otherwise described herein, niobium is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, niobium is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, niobium is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, niobium is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, niobium is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0050] In various embodiments as otherwise described herein, vanadium is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, vanadium is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, vanadium is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, vanadium is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, vanadium is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0051] In various embodiments as otherwise described herein, zirconium is present in the catalyst in an amount in the range of 0.5 to 20 wt%, based on total weight of the catalyst. For example, in various embodiments, zirconium is present in the catalyst in an amount in the range of 0.5 to 15 wt%, or 0.5 to 12 wt%, or 0.5 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, zirconium is present in the catalyst in an amount in the range of 1 to 20 wt%, e.g., in the range of 1 to 15 wt%, or 1 to 12 wt%, or 1 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, zirconium is present in an amount in the range of 2 to 20 wt%, e.g., in the range of 2 to 15 wt%, or 2 to 12 wt%, or 2 to 10 wt%, based on the total weight of the catalyst. In various embodiments of the present disclosure as described herein, zirconium is present in an amount in the range of 4 to 20 wt%, e.g., in the range of 4 to 15 wt%, or 4 to 12 wt%, or 4 to 10 wt%, based on the total weight of the catalyst.

[0052] As described above, the supported rWGS catalysts of the disclosure optionally include at least one of platinum, palladium, gold, and nickel. For example, in variousembodiments as otherwise described herein, platinum is present in the catalyst. For the purposes of this disclosure, the amount of platinum present is calculated as a weight percentage of platinum atoms in the catalyst based on the total weight of the catalyst, despite the form in which that platinum may be present. The platinum may be present in the catalyst in a variety of forms; most commonly, platinum is principally present as metal, metal oxide, or a combination thereof. In some embodiments of the present disclosure as described herein, platinum is present in the catalyst in an amount in the range of 0.05 to 10 wt%, e.g., in the range of 0.1 to 10 wt%, or 0.5 to 10 wt%, 1 to 10 wt%, or 2 to 10 wt%, or 5 to 10 wt%, based on the total weight of the catalyst. For example, in some embodiments, platinum is present in the catalyst in an amount in the range of 0.05 to 7 wt%, e.g., in the range of 0.1 to 7 wt%, or 0.5 to 7 wt%, or 1 to 7 wt%, or 2 to 7 wt%, based on the total weight of the catalyst. In some embodiments, platinum is present in the catalyst in an amount in the range of 0.05 to 5 wt%, e.g., in the range of 0.1 to 5 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, or 2 to 5 wt%, based on the total weight of the catalyst. For example, in some embodiments of the present disclosure as described herein, platinum is present in the catalyst in an amount in the range of 0.05 to 2 wt%, e.g., in the range of 0.1 to 2 wt%, or 0.3 to 2 wt%, or 0.5 to 2 wt%, based on the total weight of the catalyst. In some embodiments, platinum is present in the catalyst in an amount in the range of 0.05 to 1.5 wt%, e.g., in the range of 0.1 to 1.5 wt%, or 0.3 to 1.5 wt%, or 0.5 to 1.5 wt%, based on the total weight of the catalyst. In some embodiments, platinum is present in an amount in the range of 0.05 to 1 wt%, e.g., in the range of 0.1 to 1 wt%, or 0.3 to 1 wt%, or 0.5 to 1 wt%, based on the total weight of the catalyst. In some embodiments, platinum is present in the catalyst in an amount in the range of 0.05 to 0.8 wt%, e.g., in the range of 0.1 to 0.8 wt%, or 0.3 to 0.8 wt%, or 0.5 to 0.8 wt%, based on the total weight of the catalyst.

[0053] In various embodiments as otherwise described herein, palladium is present in the catalyst. For the purposes of this disclosure, the amount of palladium present is calculated as a weight percentage of palladium atoms in the catalyst based on the total weight of the catalyst, despite the form in which that palladium may be present. The palladium may be present in the catalyst in a variety of forms; most commonly, palladium is principally present as metal, metal oxide, or a combination thereof. In some embodiments of the present disclosure as described herein, palladium is present in the catalyst in an amount in the range of 0.05 to 10 wt%, e.g., in the range of 0.1 to 10 wt%, or 0.5 to 10 wt%, 1 to 10 wt%, or 2 to 10 wt%, or 5 to 10 wt%, based on the total weight of the catalyst. For example, in some embodiments, palladium is present in the catalyst in an amount in the range of 0.05 to 7 wt%, e.g., in the range of 0.1 to 7 wt%, or 0.5 to 7 wt%, or 1 to 7 wt%, or 2 to 7 wt%, based on the total weight of the catalyst. In some embodiments, palladium is present in thecatalyst in an amount in the range of 0.05 to 5 wt%, e.g., in the range of 0.1 to 5 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, or 2 to 5 wt%, based on the total weight of the catalyst. For example, in some embodiments of the present disclosure as described herein, palladium is present in the catalyst in an amount in the range of 0.05 to 2 wt%, e.g., in the range of 0.1 to 2 wt%, or 0.3 to 2 wt%, or 0.5 to 2 wt%, based on the total weight of the catalyst. In some embodiments, palladium is present in the catalyst in an amount in the range of 0.05 to 1.5 wt%, e.g., in the range of 0.1 to 1.5 wt%, or 0.3 to 1.5 wt%, or 0.5 to 1.5 wt%, based on the total weight of the catalyst. In some embodiments, palladium is present in an amount in the range of 0.05 to 1 wt%, e.g., in the range of 0.1 to 1 wt%, or 0.3 to 1 wt%, or 0.5 to 1 wt%, based on the total weight of the catalyst. In some embodiments, palladium is present in the catalyst in an amount in the range of 0.05 to 0.8 wt%, e.g., in the range of 0.1 to 0.8 wt%, or 0.3 to 0.8 wt%, or 0.5 to 0.8 wt%, based on the total weight of the catalyst.

[0054] In various embodiments as otherwise described herein, gold is present in the catalyst. For the purposes of this disclosure, the amount of gold present is calculated as a weight percentage of gold atoms in the catalyst based on the total weight of the catalyst, despite the form in which that palladium may be present. The gold may be present in the catalyst in a variety of forms; most commonly, gold is principally present as metal, metal oxide, or a combination thereof. In some embodiments of the present disclosure as described herein, gold is present in the catalyst in an amount in the range of 0.05 to 10 wt%, e.g., in the range of 0.1 to 10 wt%, or 0.5 to 10 wt%, 1 to 10 wt%, or 2 to 10 wt%, or 5 to 10 wt%, based on the total weight of the catalyst. For example, in some embodiments, gold is present in the catalyst in an amount in the range of 0.05 to 7 wt%, e.g., in the range of 0.1 to 7 wt%, or 0.5 to 7 wt%, or 1 to 7 wt%, or 2 to 7 wt%, based on the total weight of the catalyst. In some embodiments, gold is present in the catalyst in an amount in the range of 0.05 to 5 wt%, e.g., in the range of 0.1 to 5 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, or 2 to 5 wt%, based on the total weight of the catalyst. For example, in some embodiments of the present disclosure as described herein, gold is present in the catalyst in an amount in the range of 0.05 to 2 wt%, e.g., in the range of 0.1 to 2 wt%, or 0.3 to 2 wt%, or 0.5 to 2 wt%, based on the total weight of the catalyst. In some embodiments, gold is present in the catalyst in an amount in the range of 0.05 to 1.5 wt%, e.g., in the range of 0.1 to 1.5 wt%, or 0.3 to 1.5 wt%, or 0.5 to 1.5 wt%, based on the total weight of the catalyst. In some embodiments, gold is present in an amount in the range of 0.05 to 1 wt%, e.g., in the range of 0.1 to 1 wt%, or 0.3 to 1 wt%, or 0.5 to 1 wt%, based on the total weight of the catalyst. In some embodiments, gold is present in the catalyst in an amount in the range of 0.05 to 0.8 wt%, e.g., in the range of 0.1 to 0.8 wt%, or 0.3 to 0.8 wt%, or 0.5 to 0.8 wt%, based on the total weight of the catalyst.

[0055] In various embodiments as otherwise described herein, nickel is present in the catalyst. For the purposes of this disclosure, the amount of nickel present is calculated as a weight percentage of nickel atoms in the catalyst based on the total weight of the catalyst, despite the form in which that nickel may be present. The nickel may be present in the catalyst in a variety of forms; most commonly, nickel is principally present as metal, metal oxide, or a combination thereof. In some embodiments of the present disclosure as described herein, nickel is present in the catalyst in an amount in the range of 0.05 to 10 wt%, e.g., in the range of 0.1 to 10 wt%, or 0.5 to 10 wt%, 1 to 10 wt%, or 2 to 10 wt%, or 5 to 10 wt%, based on the total weight of the catalyst. For example, in some embodiments, nickel is present in the catalyst in an amount in the range of 0.05 to 7 wt%, e.g., in the range of 0.1 to 7 wt%, or 0.5 to 7 wt%, or 1 to 7 wt%, or 2 to 7 wt%, based on the total weight of the catalyst. In some embodiments, nickel is present in the catalyst in an amount in the range of 0.05 to 5 wt%, e.g., in the range of 0.1 to 5 wt%, or 0.5 to 5 wt%, or 1 to 5 wt%, or 2 to 5 wt%, based on the total weight of the catalyst. For example, in some embodiments of the present disclosure as described herein, nickel is present in the catalyst in an amount in the range of 0.05 to 2 wt%, e.g., in the range of 0.1 to 2 wt%, or 0.3 to 2 wt%, or 0.5 to 2 wt%, based on the total weight of the catalyst. In some embodiments, nickel is present in the catalyst in an amount in the range of 0.05 to 1.5 wt%, e.g., in the range of 0.1 to 1.5 wt%, or 0.3 to 1.5 wt%, or 0.5 to 1.5 wt%, based on the total weight of the catalyst. In some embodiments, nickel is present in an amount in the range of 0.05 to 1 wt%, e.g., in the range of 0.1 to 1 wt%, or 0.3 to 1 wt%, or 0.5 to 1 wt%, based on the total weight of the catalyst. In some embodiments, nickel is present in the catalyst in an amount in the range of 0.05 to 0.8 wt%, e.g., in the range of 0.1 to 0.8 wt%, or 0.3 to 0.8 wt%, or 0.5 to 0.8 wt%, based on the total weight of the catalyst.

[0056] The platinum, palladium, gold, and / or nickel can be provided in a variety of weight ratios. For example, in some embodiments as described herein, the weight ratio of platinum, palladium, gold, and / or nickel to metal present in the catalyst is at least 0.05:1. For example, in various embodiments, the weight ratio of platinum, palladium, gold, and / or nickel to metal is at least 0.1 :1. In various embodiments of the present disclosure as described herein, the weight ratio of platinum, palladium, gold, and / or nickel to metal present in the catalyst is at most 1:1. For example, the weight ratio of platinum, palladium, gold, and / or nickel to metal is at most 0.5:1. For example, in various embodiments, the weight ratio of platinum, palladium, gold, and / or nickel to metal present in the catalyst is in the range of 0.05:1 to 1 :1. For example, the weight ratio of platinum, palladium, gold, and / or nickel to metal is in the range of 0.05:1 to 0.5:1 , or 0.05:1 to 0.3:1 , or 0.07:1 to 1:1, or 0.07:1 to 0.5:1 , or 0.07:1 to 0.3:1 , or 0.1:1 to 1 :1 , or 0.1:1 to 0.5:1 , or 0.1:1 to 0.3:1.

[0057] The present inventors have determined that suitable rWGS catalysts can be formed of one or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide as a support, with a metal and optionally with platinum, palladium, gold, and / or nickel included in / on the catalyst. As would be understood by the person of ordinary skill in the art, the amount of cerium, titanium, aluminum, zinc, zirconium, metal, and platinum, palladium, gold, and nickel (if present) can be quantified on a metallic basis regardless of the form in which these metals may be present. For example, the amount of these metals can be calculated as a weight percentage based on the total weight of metals in the catalysts (i.e. , on a metallic basis), without the inclusion of oxygen or non-metallic counterions in the calculation. Accordingly, in various embodiments of the present disclosure as described herein, the total amount of cerium, titanium, aluminum, zinc, zirconium, and metal in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. For example, in some particular embodiments, the total amount of cerium and metal in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of titanium and metal in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of aluminum and metal in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of zinc and metal in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of zirconium and metal in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In various embodiments as described herein, the total amount of cerium, titanium, aluminum, zinc, zirconium, metal, platinum, palladium, gold, and nickel in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. For example, in some particular embodiments, the total amount of cerium, metal, platinum, palladium, gold, and nickel in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of titanium, metal, platinum, palladium, gold, and nickel in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of aluminum, metal, platinum, palladium, gold, and nickel in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of zinc, metal, platinum, palladium, gold, and nickel in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis. In other embodiments, the total amount of zirconium, metal,platinum, palladium, gold, and nickel in the catalyst is at least 90 wt%, e.g., at least 95 wt%, or at least 98 wt% of the catalyst, on a metallic basis.

[0058] As described above, the supported catalyst includes metals and optionally at least one of platinum, palladium, gold, and nickel. Depending on the process of synthesis, these species, which will typically be principally present in metallic form and / or oxide form, can be disposed at a variety of different places on the support. For example, they can be found in pores of the support and on the outer surface of the support. They may be found substantially throughout the support, e.g., as when a large volume of impregnation liquid is used, or only in a surface layer of the support, e.g., when impregnation liquid does not infiltrate into the entirety of the support, such as when using an incipient wetness technique.

[0059] Without intending to be bound by theory, it is believed that the active form of platinum and palladium is typically a substantially metallic form. As described below, as platinum and palladium may be present substantially in an oxide form after catalyst preparation and during shipment and storage, it is typically desirable to activate the catalyst by contacting it with a reductant, e.g., hydrogen gas, to convert a substantial fraction of such oxide to metallic form. However, the person of ordinary skill in the art will appreciate that the present disclosure contemplates the usefulness of a wide variety of palladium and platinum forms in its catalysts, as these can be active or can be conveniently transformed to active forms.

[0060] The metal will typically be provided in oxide form after catalyst preparation and during shipment and storage. Without intending to be bound by theory, the present inventors believe that the metal acts to improve the catalytic activity of the supported platinum, palladium, gold, and / or nickel catalysts by reducing CO methanation that can occur over the typical reverse water-gas shift reaction temperature range, which impacts CO selectivity. The present inventors believe that the improved activity can be attributed to the metal interfacing with the support (e.g., cerium oxide, titanium oxide, aluminum oxide, zinc oxide, zirconium oxide, or a mixed oxide). Additionally, when platinum, palladium, gold, and nickel are present in the catalyst, the present inventors believe that the improved activity can be attributed to the metal interfacing with both the noble metals and the support. The present inventors contemplate that it is possible that some metal oxide is converted to metallic form during the activation of the platinum, palladium, gold, and / or nickel species. However, the person of ordinary skill in the art will appreciate that the present disclosure contemplates the usefulness of a wide variety of metal forms in its catalysts, as these can provide a promoting effect or can be conveniently transformed to forms that will.

[0061] The person of ordinary skill in the art will appreciate that the rWGS catalysts as described herein can be provided in many forms, depending especially on the particular form of the reactor system in which they are to be used, e.g., in a fixed bed or as a fluid bed. The supports themselves can be provided as discrete bodies of material, e.g., as porous particles, pellets or shaped extrudates, with metal and optionally, palladium, platinum, gold, and / or nickel provided thereon to provide the catalyst. However, in other embodiments, a catalyst of the disclosure can itself be formed as a layer on an underlying substrate. The underlying substrate is not particularly limited. It can be formed of, e.g., a metal or metal oxide, and can itself be provided in a number of forms, such as particles, pellets, shaped extrudates, or monoliths. The person of ordinary skill in the art can, e.g., use coating or other forming techniques to provide a layer of support on the substrate, then add metal and optionally, platinum, palladium, gold, and / or nickel. The person of ordinary skill in the art will select an appropriate rWGS catalyst for the particular reactor system.

[0062] In various embodiments as otherwise described herein, the rWGS catalysts as disclosed herein is prepared by providing a support that is a cerium oxide support, a titanium oxide support, an aluminum oxide support, a zinc oxide support, a zirconium oxide support, or a mixed oxide support including a mixture of two or more of cerium oxide, titanium oxide, aluminum oxide, zinc oxide, and zirconium oxide; contacting the support with one or more liquids each comprising one or more metal-containing compounds dispersed in a solvent(s), wherein the metal is selected from manganese, copper, gallium, indium, lanthanum, titanium, niobium, vanadium, and zirconium, and optionally one or more platinum-, palladium-, gold-, or nickel-containing compounds; allowing the solvent(s) to evaporate to provide a catalyst precursor; and calcining the catalyst precursor. The person of ordinary skill in the art will appreciate, of course, that other methods can be used to make the catalysts described herein.

[0063] In some embodiments as described herein, contacting the support with the liquid includes adding the liquid in an amount about equal to (i.e., within 25% of, or within 10% of) the pore volume of the support. In other embodiments, contacting the support with the liquid includes adding the liquid in an amount greater than the pore volume of the support. For example, in some embodiments, the ratio of the amount of liquid to the amount of support on a mass basis is in the range of 0.75:1 to 5:1 , e.g., in the range of 0.9:1 to 3:1. In some embodiments, contacting the support with the liquid provides a slurry.

[0064] In various embodiments as described herein, allowing the solvent to evaporate is conducted at ambient temperature. In various embodiments, allowing the solvent to evaporate is conducted at an elevated temperature for a drying time. The person of ordinaryskill in the art would be able to select appropriate apparatuses or instruments to allow the solvent to evaporate, and such apparatuses or instruments are not particularly limited. Additionally, the person of ordinary skill in the art would understand that the elevated temperature that will allow the solvent to evaporate depends on the boiling point of the solvent. As such, the person of ordinary skill in the art would be able to select an appropriate elevated temperature. For example, in some embodiments, the elevated temperature is in the range of 50-150 °C, e.g., in the range of 50-120 °C, or 50-100 °C, or 100-150 °C, or 100-120 °C. In some embodiments, the drying time is in the range of 1 to 48 hours, e.g., in the range of 10 to 36 hours, or 12 to 24 hours. For example, in particular embodiments, the drying time is about 24 hours. In some embodiments, allowing the solvent to evaporate is conducted under vacuum and at an elevated temperature for a drying time, as described herein. In some embodiments, allowing the solvent to evaporate is conducted in a stirring dry bath at an elevated temperature, for example, in the range of 30-100 °C.

[0065] In some embodiments as described herein, calcining the catalyst precursor is conducted in a furnace for a calcining time and at a calcining temperature. For example, in some embodiments, the calcining time is in the range of 0.5 to 24 hours, or 0.5 to 15 hours, or 0.5 to 10 hours, or 0.5 to 5 hours. In some embodiments, the calcining temperature is in the range of 100-600 °C, e.g., in the range of 120-500 °C.

[0066] As described above, the method of making the catalyst as described herein includes contacting the support with one or more liquids each including one or more metalcontaining compounds and optionally, one or more platinum-, palladium-, gold-, or nickel- containing compounds dispersed in a solvent. The platinum-, palladium-, gold-, and metalcontaining compounds are not particularly limited and the person of ordinary skill in the art would be able to choose appropriate compounds that are soluble in the solvent. For example, in some embodiments of the disclosure as described herein, the platinum-, palladium-, gold-, and metal-containing compounds may be selected from metal salts (e.g., nitrates and acetates). The solvent is also not particularly limited and the person of ordinary skill in the art would be able to choose an appropriate solvent that can be absorbed by the support. For example, in some embodiments of the disclosure as described herein, the solvent is water. As the person of ordinary skill in the art will appreciate, these metal species are conveniently provided in the same liquid, so that only one step of contacting the support with liquid is required. However, other schemes are possible.

[0067] In various embodiments as otherwise described herein, the present disclosure provides an rWGS catalyst as described herein made by the methods as described herein.

[0068] Reverse Water-Gas Shift Processes

[0069] As noted above, the process as described herein includes contacting a shift feed stream comprising carbon dioxide and hydrogen with an rWGS catalyst under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water. An example of such a method is shown schematically in FIG. 1. In FIG. 1 , the method 100 includes performing an rWGS reaction by providing a feed stream 111 comprising H2 and CO2, here, to a reaction zone, e.g., a reactor 110. An rWGS catalyst 113, as described herein, is contacted with the shift feed stream 111 to provide a shift product stream 112 comprising CO2, H2, CO, and H2O. The shift product stream has a lower concentration of CO2 and a higher concentration of CO than the shift feed stream.

[0070] As used herein, a “feed stream” is used to mean the total material input to a process step, e.g., an rWGS or FT reaction, regardless of whether provided in a single physical stream or multiple physical streams, and whether through a single inlet or multiple inlets. For example, H2 and CO of the shift feed stream can be provided to the rWGS catalyst in a single physical stream (e.g., in a single pipe to reactor 110), or in multiple physical streams (e.g., separate inlets for CO and H2, or one inlet for fresh CO and H2 and another for recycled CO and / or H2). Similarly, a “product stream” is used to mean the total material output from a process step, regardless of whether provided in a single physical stream or multiple physical streams, and whether through a single outlet or multiple outlets.

[0071] As described above, the shift feed stream contains both H2 and CO2 (e.g., provided to a reaction zone in a single physical stream or multiple physical streams). In various embodiments as otherwise described herein, the molar ratio of H2 to CO2 in the shift feed stream is in the range of 2-4. In some embodiments, the molar ratio of H2 to CO2 in the shift feed stream is in the range of 2-3.5. In some embodiments, the molar ratio of H2 to CO2 in the shift feed stream is in the range of 2-3. In some embodiments, the molar ratio of H2 to CO2 in the shift feed stream is in the range of 2-2.5. The person of ordinary skill in the art will provide a desired ratio of H2:CO2 in the shift feed stream, based on the disclosure herein, that provides a desirable conversion and selectivity; excess H2 can, if consistent with a desirable conversion and selectivity, be provided to flow through the system and provide a product stream with a desirable ratio of H2 to CO for a downstream process, e.g., an FT process.

[0072] Other gases may also be included in the shift feed stream. For example, in some embodiments, the shift feed stream further comprises CO. In some embodiments as otherwise described herein, the shift feed stream further comprises one or more inert gases. For example, in some embodiments, the shift feed stream further comprises nitrogen and / or methane.

[0073] The process as described herein includes contacting the shift feed stream comprising CO2 and H2 with an rWGS catalyst to perform an rWGS reaction. Notably, the present inventors have determined that the rWGS catalysts described herein can provide desirably high CO selectivity. For example, in various embodiments as described herein, the rWGS reaction has a CO selectivity of at least 70%, e.g., of at least 80%. In various embodiments, the rWGS reaction has a CO selectivity of at least 85%, e.g., or at least 90%. In various embodiments, the rWGS reaction has a CO selectivity of at least 95%, e.g., or at least 96%. As used herein, a “selectivity” for a given reaction product is the molar fraction of the relevant component of the feed (here, CO2) that is converted to the product (for “CO selectivity,” CO). The present inventors have determined that the present rWGS catalysts as described herein, even when operating at lower temperatures than many conventional rWGS catalysts, can provide excellent selectivity for CO, despite the potential for competition by the Sabatier reaction and the methanation of CO. For example, in some embodiments as otherwise described herein, the rWGS reaction has a CO selectivity of at least 98%, e.g., or at least 99%.

[0074] Notably, even over a broad range of temperatures, e.g., within the range of 200- 800 °C, the rWGS catalysts as described herein can be operated to provide carbon monoxide with only a very minor degree of methane formation. For example, in various embodiments as described herein, the rWGS reaction has a methane selectivity of no more than 5%, e.g., no more than 4%. For example, in some embodiments, the rWGS reaction has a methane selectivity of no more than 2%, e.g., no more than 1%. In some embodiments, the rWGS reaction has a methane selectivity of no more than 0.5%, e.g., no more than 0.2%.

[0075] The present inventors have determined that the rWGS catalysts as described herein can provide desirably high CO selectivity and desirably low methane selectivity at commercially relevant conversion rates. As used herein, a “conversion” is a molar fraction of a relevant component feed that is reacted (be it to desirable products or undesirable species). In various embodiments as described herein, the rWGS reaction has a CO2 conversion of at least 5%, e.g., at least 10%, or at least 20%. For example, in some embodiments, the rWGS reaction has a CO2 conversion of at least 30%, e.g., at least 40%, or at least 50%, or at least 60%. In various embodiments as described herein, the rWGS reaction has a CO2 conversion of no more than 80%, e.g., no more than 70%. For example, in some embodiments, the rWGS reaction has a CO2 conversion of no more than 65%, e.g., no more than 60%. For example, in various embodiments as otherwise described herein, the CO2 conversion is in the range of 10-80%, e.g., 10-70%, or 10-60%, or 10-65%, or 20- 80%, or 20-70%, or 20-60%, or 20-65%, or 30-80%, or 30-70%, or 30-60%, or 30-65%, or40-80%, or 40-70%, or 40-60%, or 40-65%. The person of ordinary skill in the art will, based on the disclosure herein, operate at a degree of conversion that provides a desirable product. And of course, in other embodiments, e.g., when in a stacked-bed or mixed-bed system, the effective CO2 conversion may be even higher than described herein.

[0076] But as described below, it can be desirable to operate the rWGS stage at a relatively lower conversion, to provide relatively more CO2 throughput to the FT feed stream and thus maintain high CO2:CO ratios. Thus, in various embodiments, the rWGS reaction has a CO2 conversion in the range of 5-35%, e.g., 5-30%, or 5-25%, or 5-20%, or 10-35%, or 10-30%, or 10-25%.

[0077] Advantageously, the rWGS processes as described herein can be performed at temperatures that are lower than temperatures used in many conventional rWGS processes. As described above, various processes of performing an rWGS reaction of the disclosure can be performed at a temperature in the range of 180-400 °C. For example, in some embodiments, the rWGS reaction is conducted at a temperature in the range of 180-450 °C, or 180-400 °C, or 180-350 °C, or 180-300 °C, or 180-250 °C, or 180-200 °C. In some embodiments, the process for performing the rWGS reaction is conducted at a temperature in the range of 200-400 °C, e.g., in the range of 200-350 °C, or 200-300 °C, or 200-250 °C. In some embodiments, the process for performing the rWGS reaction is conducted at a temperature in the range of 250-400 °C, e.g., in the range of 250-350 °C, or 250-300 °C. In some embodiments, the process for performing the rWGS is conducted at a temperature in the range of 300-400 °C, e.g., in the range of 300-350 °C. The present inventors have noted that operation at these temperatures can provide for lower energy demand, as well as for facile integration with a subsequent FT process.

[0078] Additionally, the rWGS processes as described herein can be performed at a variety of pressures, as would be appreciated by the person of ordinary skill in the art. In various embodiments, the process for performing the rWGS reaction is conducted at a pressure in the range of 10-100 barg. For example, the rWGS process is conducted at a pressure in the range of 10-90 barg, or 10-80 barg, or 10-70 barg, or 10-60 barg, or 10-50 barg, or 10-40 barg, or 10-30 barg, or 10-20 barg, or 15-100 barg, or 15-90 barg, or 15-80 barg, or 15-70 barg, or 15-60 barg, or 15-50 barg, or 15-40 barg, or 15-30 barg, or 15-20 barg, or 20-100 barg, or 20-90 barg, or 20-80 barg, or 20-70 barg, or 20-60 barg, or 20-50 barg, or 20-40 barg, or 20-30 barg, or 25-100 barg, or 25-90 barg, or 25-80 barg, or 25-70 barg, or 25-60 barg, or 25-50 barg, or 25-40 barg, or 25-30 barg.

[0079] In various embodiments as described herein, the rWGS processes as described herein can be performed at a temperature of no more than 400 °C (e.g., in the range of 180-400 °C, or 180-350 °C, or 180-300 °C, or 180-250 °C) and at a pressure of at least 20 barg (e.g., in the range of 20-30 barg, or 20-40 barg, or 20-50 barg, or 20-60 barg, or 20-70 barg).

[0080] The rWGS processes as described herein can be performed at a variety of GHSV (gas hourly space velocity), as would be appreciated by the person of ordinary skill in the art. As such, the GHSV for performing the rWGS reaction is not particularly limited. For example, in some embodiments, the process for performing the rWGS reaction is conducted at a GHSV in the range of 1,000 to 2,000,000 IT1. In various embodiments, the process for performing the rWGS reaction is conducted at a GHSV in the range of 1,000 to 1 ,200,000 IT1, or 1 ,000 to 500,000 IT1, or 1,000 to 100,000 IT1, or 5,000 to 1,200,000 IT1, or 5,000 to 500,000 IT1, or 5,000 to 100,000 IT1, or 10,000 to 1,200,000 IT1, or 10,000 to 500,000 IT1, or 10,000 to 100,000 h’1. In various embodiments, the process for performing the rWGS reaction is conducted at a GHSV in the range of 1 ,000 to 50,000 IT1, or 2,000 to 50,000 IT1, or 5,000 to 50,000 IT1, or 10, 000 to 50,000, or 1,000 to 40,000 IT1, or 2,000 to 40,000 IT1, or 5,000 to 40,000 IT1, or 10, 000 to 40,000 IT1, or 1,000 to 30,000 IT1, or 2,000 to 30,000 IT1, or 5,000 to 30,000 IT1, or 10,000 to 30,000 IT1. The person of ordinary skill in the art will appreciate that not all disclosed ranges of space velocities may be available for a particular process.

[0081] It will typically be desirable to activate the rWGS catalyst, e.g., before contacting with the shift feed stream. Thus, in some embodiments as described herein, the process further comprises activating the rWGS catalyst prior to contacting the catalyst with the shift feed stream. For example, in some embodiments, activating the catalyst comprises contacting the catalyst with a reducing stream comprising a reductive gas, e.g., hydrogen. In various embodiments, the reducing stream comprises hydrogen in an amount of at least 25 mol%, e.g., at least 50 mol%, or 75 mol%, or 90 mol%. The person of ordinary skill in the art will determine suitable conditions for reducing activation of the rWGS catalyst. As such, the person or ordinary skill in the art would be able to choose an appropriate temperature, pressure, and time for activating the rWGS catalyst. For example, in various embodiments, activating the rWGS catalyst is conducted at a temperature in the range of 200 °C to 800 °C. For example, in various embodiment, activating the rWGS catalyst is conducted at a temperature in the range of 250 °C to 800 °C, or 300 °C to 800 °C, or 200 °C to 700 °C, or 250 °C to 800 °C, or 300 °C to 700 °C. In some embodiments as described herein, activating the rWGS catalyst provides an rWGS catalyst that is at least 10% reduced (e.g., at least 25%, or at least 50% reduced).

[0082] The present inventors have found that contacting the shift feed stream with an rWGS catalyst as described herein can provide a shift product stream with advantageouslyhigh CO selectivity and low methane selectivity. The amount of CO in the shift product stream can be further controlled by the rWGS reaction conditions, as described above. For example, in various embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of CO2 of no more than 65%, or no more than 60%. In some embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of CO2 of no more than 55%, or no more than 50%. In some embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of C020f no more than 45%, or no more than 40%. In some embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of CO2 of no more than 35%, or no more than 30%. In some embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of C020f no more than 25%, or no more than 20%. In some embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of CO2 of no more than 15%, or no more than 10%. In other embodiments, the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of CO2 in the range of 10-60%, e.g., in the range of 10-50%, or 10-40%, or 10-30%, or 10-20%.

[0083] The person of ordinary skill in the art would appreciate that, based on the processes as described herein, the shift product stream may include CO2, H2, CO, water, and other components in various amounts. Components of the shift product stream may be separated and used for various purposes in the integrated FT process.

[0084] For example, in various embodiments as described herein, the process further comprises separating the shift product stream to recycle at least a portion (e.g., at least 5 mol%, at least 10 mol%, at least 25 mol%, at least 50 mol%, at least 75 mol%, or at least 90 mol%) of the one or more components of the shift product stream to the shift feed stream. For example, when the shift product stream includes CO2, the process can include recycling at least a portion (e.g., at least 5 mol%, at least 10 mol%, at least 25 mol%, at least 50 mol%, at least 75 mol%, or at least 90 mol%) of the CO2 in the shift product stream to the shift feed stream. The shift product stream may also include H2, and thus, in some embodiments, the process further includes recycling at least a portion of H2 in the shift product stream (e.g., at least 5 mol%, at least 10 mol%, at least 25 mol%, at least 50 mol%, at least 75 mol%, or at least 90 mol%) to the shift feed stream.

[0085] Such recycling is shown in the process 100 of FIG. 1. Here, the process 100 includes separating from the shift product stream 112 at least a portion of CO2 (stream 114) to recycle to the shift feed stream 111. Similarly, the process 100 includes separating from the shift product stream 112 at least a portion of H2 (stream 115) to recycle to the shiftproduct stream 111. While stream 115 is depicted as entering reactor 110 through a different inlet than the rest of the shift feed stream 111 , it is considered to be part of the shift feed stream, as it is part of the material input to the rWGS process as described herein.

[0086] Moreover, as described below, iron-based FT catalysts are often activated by reduction by a reducing gas followed by carbiding with a carbon oxide-containing gas. This can be performed in sequence, or via treatment with a single gas stream containing both H2 and CO. In either case, H2 and CO from the shift product stream can be used to perform this activation. For example, in some embodiments as otherwise described herein, the process includes separating at least a portion of H2 and CO (desirably in a ratio of at least 1:1 or at least 3:1) from the shift product stream and contacting it with the FT catalyst to activate the FT catalyst. In various other embodiments as otherwise described herein, the process includes separating at least a portion of H2 from the shift product stream and contacting it with the FT catalyst to activate the FT catalyst. For example, in the process of FIG. 1, stream 125 separates H2 and CO and conducts them to reactor 120. This separation need not be continuous; rather, it need only be performed for a time desirable to provide reducing gas to the FT catalyst for activation. Of course, as would be understood by the person of skill in the art, other sources of H2 or CO may be used to provide reducing gas to the FT catalyst for activation.

[0087] As shown above, water is a product of the rWGS reaction. Accordingly, the shift product stream will generally contain water. In many cases, it can be desirable to reduce the amount of water that is provided to the FT process. Accordingly, in various embodiments as otherwise described herein, the process further includes removing at least a portion (e.g., at least 25%, at least 50%, or at least 75%) of the water from the shift product stream. In the embodiment of FIG. 1 , a water removal zone 116 is used to remove water and provide a water-containing stream 117. The person of ordinary skill in the art will appreciate that a variety of processes can be used to remove water from the shift product stream. For example, the shift product stream can be contacted with a water scavenger to remove water therefrom. For example, a molecular sieve guard bed can be used to remove water from the shift product stream, where water can be recovered from the molecular sieves of the guard bed, e.g., by heating and vacuum. In other embodiments, a knockout vessel can be used to remove water. However, use of a knockout vessel can in some cases cool the shift product stream to such a degree that it is desirably reheated for introduction to the FT process.

[0088] As noted above, one competing reaction in the rWGS reaction is the Sabatier reaction, which makes methane. While in various embodiments the rWGS processes as described herein can be performed without forming large amounts of methane, in someembodiments there can be some methane formed. Accordingly, in various embodiments of the process as described herein, the shift product stream comprises one or more light hydrocarbons. For example, in some embodiments, the shift product stream may include one or more of methane, ethane, propane, or combinations thereof. As would be understood by the person of ordinary skill in the art, it may be desirable to operate the rWGS reaction to provide higher amounts of light hydrocarbons in the shift product feed. For example, such light hydrocarbons may be inert in further processing of the shift product stream and so may be acceptable at higher amounts. The person of ordinary skill in the art would be able to select appropriate reaction conditions (e.g., temperature, pressure, first feed stream composition) to provide a shift product stream that includes methane at a desired amount. For example, in various embodiments as otherwise described herein, the shift product stream includes no more than 20 mol% methane or no more than 15 mol%. As noted above, when lower amounts of methane are desired in the shift product stream, the rWGS catalysts of the disclosure can provide very low methane selectivity. Accordingly, in various embodiments as otherwise described herein, the shift product stream includes no more than 10 mol% methane. For example, in various embodiments, the shift product stream includes no more than 5 mol%, or no more thanl mol%, or no more than 0.5 mol%, or no more than 0.1 mol% methane.

[0089] These light hydrocarbons can be separated and used for other purposes. For example, in various embodiments, the process further includes separating at least a portion of one or more light hydrocarbons from the shift product stream to provide a light hydrocarbon stream. For example, in process 100 of FIG. 1, at least a portion of one or more light hydrocarbons are separated from the shift product stream 112 to provide a light hydrocarbon stream 118. The light hydrocarbon stream, for example, can be used to provide other products, can be partially oxidized to form CO, can be steam reformed to provide hydrogen, and / or can be burned to provide heat or other energy (e.g., electricity for electrolysis) for use in the integrated process or otherwise. Of course, as would be understood by the person of ordinary skill in the art, the light hydrocarbon stream may be used in other processes.

[0090] As noted above, the rWGS process can be provided at a wide variety of temperatures. In some cases, those temperatures can be relatively close to the temperature of the subsequent FT process (often 150-400 °C, e.g., 200-350 °C, or other temperatures as described below). In other cases, the rWGS process can be performed at temperatures significantly higher than the temperature of the FT process. The present inventors have noted that it can be desirable to provide for heat exchange with a relatively hot shift product stream to cool the shift product stream to a temperature more appropriate for the FT processand to provide heat elsewhere to the integrated process. For example, in various embodiments as otherwise described herein, the process further comprises exchanging heat between at least a portion of the shift product stream and at least a portion of the shift feed stream, thereby cooling at least a portion of the shift product stream and heating at least a portion of the shift feed stream. An example of such a process is shown schematically in FIG. 2. In FIG. 2, the process 200, first reactor 210, shift feed stream 211 , shift product stream 212, rWGS catalyst 213, second reactor 220, FT feed stream 221, FT product stream 222 and FT catalyst 223 are generally as described above. Here, the process 200 includes exchanging heat between at least a portion of the shift product stream 212 and a least a portion of the shift feed stream 211 in a first heat exchange zone 230, thereby cooling at least a portion of the shift product stream 212 and heating at least a portion of the shift feed stream 211. The person of ordinary skill in the art will appreciate that a wide variety of heat exchangers can be used for this purpose.

[0091] Of course, any excess heat in the first shift product stream can be additionally or alternatively used for other purposes. For example, in various embodiments, the process further comprises exchanging heat between at least a portion of the first shift product stream and a steam generation zone, thereby cooling at least a portion of the first shift product stream and providing heat to the steam generation zone. This is shown in FIG. 2. Here, after heat exchange with the shift feed stream 211 , the shift product stream 212 is conducted to steam generation zone 232, to cool the shift product stream 212 and provide heat to the steam generation zone 232. Steam can be generated from the heat provided, and electricity can be generated from the steam. For example, in the embodiment of FIG. 2, electricity stream 264 is provided by the generation of electricity using steam generated in the steam generation zone 232. Of course, as would be understood to the person of ordinary skill in the art, the steam generated in the steam generation zone may be used in other processes. In various embodiments, the steam may be used to heat the shift feed stream. For example, in the embodiment of FIG. 2, the steam stream 266 generated in the steam generation zone 232 is conducted to the heat exchange zone 290 to heat the shift feed stream 211.

[0092] As described herein, the process further includes providing an FT feed stream comprising at least a portion of the carbon monoxide, hydrogen, and carbon dioxide from the shift product stream. The FT feed stream comprises at least 5 mol% carbon dioxide, and has a molar ratio of carbon dioxide to carbon monoxide of at least 2, e.g., at least 2.5 or at least 3.

[0093] As noted above, at least a portion of the CO of the shift product stream is included in the FT feed stream for reaction in an FT process. For example, in variousembodiments as otherwise described herein, at least 25% of the CO of the shift product stream, e.g., at least 50% of the CO, at least 75% of the CO, or at least 90% of the CO of the shift product stream is included in the FT feed stream. Of course, as noted above, some of the CO of the shift product stream can be used for other purposes, e.g., catalyst activation as described herein.

[0094] In some embodiments, substantially all of the CO of the FT feed stream comes from the shift product stream. However, in other embodiments, CO can be provided to the FT feed stream from other sources. For example, in various embodiments, CO is provided to the FT feed stream from a CO source other than the shift product stream. In FIG. 2, a stream of CO 226a from some other source is included in the FT feed stream 221. The person of ordinary skill in the art will appreciate that CO can be provided from a variety of sources, e.g., gasification, reforming, or electrochemical CO2 reduction. Moreover, as described in more detail below, CO can be recycled to the FT feed stream from the FT product stream.

[0095] As noted above, the FT feed stream includes hydrogen. Notably, the shift product stream will often include H2, e.g., unreacted from the shift feed stream. In various embodiments, the shift product stream includes H2, where the FT feed stream includes at least a portion of the H2 of the shift product stream. For example, in various embodiments as otherwise described herein, at least 25% of the H2 of the shift product stream, e.g., at least 50% of the H2, at least 75% of the H2, or at least 90% of the H2 in the shift product stream is included in the FT feed stream. Of course, as noted above, some of the H2 of the shift product stream can be used for other purposes, e.g., catalyst activation as described herein.

[0096] In some embodiments, substantially all of the H2 of the FT feed stream comes from the shift product stream. In fact, the person of ordinary skill in the art can provide more H2 than necessary for the rWGS reaction in the shift feed stream, to provide excess H2 in the shift product stream that can then provide a desired amount of H2 to the FT feed stream for the FT process. However, in other embodiments, H2 can be provided to the FT feed stream from other sources. For example, in various embodiments, H2 is provided to the FT feed stream from a H2 source other than the shift product stream. In FIG. 2, a stream of H2 226b from some other source is included in the FT feed stream 221. The person of ordinary skill in the art will appreciate that H2 can be provided from a variety of sources, e.g., gasification, reforming, or H2O electrolysis. Moreover, as described in more detail below, H2 can be recycled to the FT feed stream from the FT product stream.

[0097] As noted above, it is advantageous to perform the FT process in the presence of a significant level of CO2, in order to suppress the conversion of CO to CO2 by the water-gas shift activity of the iron-based FT catalyst. CO2, can conveniently be provided by the rWGS stage, e.g., via the shift product stream. Accordingly, in various embodiments as otherwise described herein, the FT feed stream comprises at least 5 mol% CO2, e.g., at least 10 mol%, at least 15 mol%. In various embodiments, the FT feed stream comprises in the range of 5- 75 mol% CO2, e.g., in the range of 5-60 mol%, or 5-45 mol%. In various embodiments, the FT feed stream comprises in the range of 10-75 mol% CO2, e.g., in the range of 10-60 mol%, or 10-45 mol%. In various embodiments, the FT feed stream comprises in the range of 15-75 mol% CO2, e.g., in the range of 15-60 mol%, or 15-45 mol%.

[0098] The amount of CO in the FT feed stream can vary, and can be selected by the person of ordinary skill in the art based on the present disclosure. An increased amount of carbon monoxide in the FT feed stream can be desirable from the standpoint of product conversion, but, critically, the ratio of CO2:CO in the feed stream should be at least 2 to suppress conversion of CO to CO2. In various embodiments as otherwise desired herein, the FT feed stream includes at least 1 mol% CO, e.g., at least 4 mol%, or at least 8 mol% CO. In various embodiments, the FT feed stream includes CO in the range of 1-20 mol%, e.g., in the range of 1-18 mol%, or 1-16 mol%, or 1-12 mol%. In various embodiments, the FT feed stream includes CO in the range of -20 mol%, e.g., in the range of 4-18 mol%, or 4- 16 mol%, or 4-12 mol%. In various embodiments, the FT feed stream includes CO in the range of 8-20 mol%, e.g., in the range of 8-18 mol%, or 8-16 mol%.

[0099] The person of ordinary skill in the art can, based on the present disclosure, select a ratio of CO2:CO in the FT feed stream that provides a desired degree of shift suppression while providing sufficient CO for reaction to desirable products. In various embodiments, the portion the FT feed stream has a CO2:CO ratio of at least 2. In various embodiments, the FT feed stream has a CO2:CO ratio of at least 3, e.g., at least 3.5, or at least 4. In various embodiments, the FT feed stream has a CO2:CO ratio in the range of 2-10, e.g., 2-8 or 2-6 or 2-5. In various embodiments, the FT feed stream has a CO2:CO ratio in the range of 2.5- 10, e.g., 2.5-8 or 2.5-6 or 2.5-5. In various embodiments, the FT feed stream has a CO2:CO ratio in the range of 3-10, e.g., 3-8 or 3-6. In various embodiments, the FT feed stream has a CC>2:CO ratio in the range of 3.5-10, e.g., 3.5-8 or 3.5-6. In various embodiments, the FT feed stream has a CO2:CO ratio in the range of 4-10, e.g., 4-8 or 4-7. The person of ordinary skill in the art can, e.g., operate the rWGS stage at relatively low conversion to provide a desired CO2:CO ratio to the FT feed stream. Of course, whatever the CO2:CO ratio of the portion of the shift product stream that is included in the FT feed stream, theperson of ordinary skill in the art can add CO2 or CO as described above as necessary to provide the desired ratio overall in the FT feed stream.

[0100] Hydrogen is also present in the FT feed stream. In various embodiments as otherwise desired herein, the FT feed stream includes at least 10 mol% H2, e.g., at least 20 mol%, or at least 30 mol% H2. In various embodiments, the FT feed stream includes H2 in the range of 10-70 mol%, e.g., in the range of 10-60 mol%, or 10-50 mol%, or 20-70 mol%, or 20-60 mol%, or 20-50 mol%, or 30-70 mol%, or 30-60 mol%, or 30-50 mol%.

[0101] The ratio of hydrogen to carbon monoxide can also vary. In various embodiments as described herein, the FT feed stream has a H2:CO ratio in the range of 0.5:1 to 6:1. In some embodiments, the FT feed stream has a H2:CO ratio in the range of 1:1 to 3:1 , or 1:1 to 2.5:1. In some embodiments, the FT feed stream has a H2:CO ratio of at least 1.4:1. For example, in some embodiments, the FT feed stream has a H2:CO ratio in the range of 1.4:1 to 6:1, e.g., 1.4:1 to 4:1 , or 1.4:1 to 2:1. The person of ordinary skill in the art will provide a desired ratio of H2:CO in the FT feed stream, based on the disclosure herein that provides a desirable conversion and selectivity in the FT process.

[0102] In some cases it can be desirable to include inert gases (e.g., nitrogen and / or Ci- 04 hydrocarbons such as methane) to the FT feed stream. For example, in various embodiments, one or more inerts (e.g., nitrogen and / or C1-C4 hydrocarbons) are provided to the FT feed stream from a source other than the shift product stream. In FIG. 2, a stream of inert(s) 226c from some other source is included in the FT feed stream 221. The person of ordinary skill in the art will appreciate that inerts can be provided from a variety of sources. Moreover, as described in more detail below, inerts can be recycled to the FT feed stream from the FT product stream.

[0103] Other gases may also be included in the FT feed stream, as described above. For example, as noted above, it can be desirable to perform the FT process in the presence of a significant amount of inerts (i.e. , components that are not H2, H2O, CO or CO2, such as nitrogen, methane and C2-C4 hydrocarbons). For example, in various embodiments, the FT feed stream includes up to 80 mol% of one or more inerts, e.g., in the range of 3-80 mol%, or 5-80 mol%, or 10-80 mol%, or 15-80 mol%, or 30-80 mol% of one or more inerts. In various embodiments, the FT feed stream includes up to 70 mol%, or up to 60 mol%, or up to 50 mol% inerts, e.g., 3-70 mol%, or 5-70 mol%, or 10-70 mol%, or 15-70 mol%, or 30-70 mol%, or 3-60 mol%, or 5-60 mol%, or 10-60 mol%, or 15-60 mol%, or 30-60 mol%, or 3-50 mol%, or 5-50 mol%, or 10-50 mol%, or 15-50 mol%, or 30-50 mol% inerts. In various embodiments, the FT feed stream includes up to 80% of one or more inerts selected from CO2, methane and nitrogen, e.g., up to 70 mol%, up to 60 mol%, or up to 50 mol%, or 15-70mol%, or 30-70 mol%, or 15-60 mol%, or 30-60 mol%, or 15-50 mol%, or 30-50 mol%. In various embodiments, the FT feed stream includes up to 80 mol% of CO2, e.g., up to 70 mol%, up to 60 mol%, or up to 50 mol%, or 15-70 mol%, or 30-70 mol%, or 15-60 mol%, or 30-60 mol%, or 15-50 mol%, or 30-50 mol%.

[0104] Conveniently, substantially all of the shift product stream can be provided to the FT feed stream. The person of ordinary skill in the art can in many cases, based on the disclosure herein, conduct the rWGS reaction to provide a desired FT feed stream. Of course, the portion of the shift product stream that is conducted to the FT feed stream can be supplemented with carbon monoxide, carbon dioxide and / or hydrogen from other sources.

[0105] However, as noted above, it can be desirable to reduce the amount of water that is conducted to the FT process. Accordingly, in various embodiments as otherwise described herein, the portion of the shift product stream that is included in the FT feed stream has a water content of no more than 10 mol%, e.g., or no more than 2 mol%, or no more than 0.5 mol%. A condensation step (e.g., using a so-called “knockout” process) can be provided to remove water from the shift product stream to provide a low-water stream that is conducted to the FT feed stream.

[0106] And as noted above, it can be desirable to perform the FT process with a relatively small amount of water present. Accordingly, in various embodiments, the FT feed stream has a water content of no more than 10 mol%, e.g., or no more than 2 mol%, or no more than 0.5 mol%.

[0107] In various embodiments as otherwise described herein, the FT feed stream comprises separating the shift product stream to provide a water-rich stream and a waterpoor shift product stream, and including at least a portion of the water-poor shift product stream in the FT feed stream.

[0108] As described herein, the process further includes contacting the FT feed stream with an FT catalyst to conduct the FT process as described herein.

[0109] Fischer-Tropsch Catalysts

[0110] The FT catalysts for use in the FT process as described herein are not particularly limited, and the person of ordinary skill in the art would be able to choose a catalyst as appropriate for the FT processes.

[0111] Amounts of various atomic species as described herein are determined using inductively coupled plasma mass spectrometry (“ICP”). As the person of ordinary skill in theart will appreciate, ICP can detect most elements, but is blind to hydrogen, nitrogen and oxygen. Accordingly, amounts quantified “on an elemental basis” are determined by ICP with respect to amounts of ICP-measurable elements, i.e., excluding hydrogen, oxygen and nitrogen. Moreover, it can be convenient to quantify as-carbided catalysts without considering carbon in the quantification. Accordingly, amounts quantified “on an elemental basis excluding carbon” are determined by ICP excluding hydrogen, oxygen, nitrogen and carbon.

[0112] As noted above, the FT catalysts as described herein comprise iron. The amount of iron is measured by ICP. For purposes of the present disclosure, the amount of iron present is calculated on an elemental basis, i.e., as a weight percentage of iron atoms based on the total weight of ICP-measurable elements in the catalyst material, regardless of the form in which that iron may be present. The iron may be present in the catalyst in a variety of forms; most commonly, iron is principally present as metal, metal carbide, metal oxide (such as a mixed metal oxide with any other metal components, or single metal oxides like Fe2C>3, FeO and FesC ), a metal carbide, a metal halide, or a combination thereof. For example, in various embodiments as described herein, the FT catalysts comprise at least 15 wt% iron, at least 20 wt% iron, or at least 25 wt% iron, on an elemental basis excluding carbon. In various embodiments as described herein, the FT catalysts comprise at least 30 wt% iron, at least 35 wt% iron, or at least 40 wt% iron, on an elemental basis excluding carbon.

[0113] In various embodiments as otherwise described herein, the FT catalyst is an alkali-promoted iron FT catalyst. The present inventors note that alkali can provide increased water-gas shift activity - as the carbon dioxide:carbon monoxide ratio is maintained at a high value, water-gas shift activity in the FT reactor can further convert CO2 to CO and through to desirable products. In various embodiments as described herein, the FT catalyst comprises in the range of 0.2-5 wt% alkali metal, on an elemental basis excluding carbon. For example, in various embodiments, the FT catalyst comprises in the range of 0.2-3 wt%, or 0.2-2 wt%, or 0.3-5 wt%, or 0.3-3 wt%, or 0.3-2 wt%, or 0.4-5 wt%, or 0.4-3 wt%, or 0.4-2 wt% alkali metal, on an elemental basis excluding carbon. In some embodiments as described herein, the FT catalyst comprises in the range of 0.5-5 wt% alkali metal, e.g., 0.5-3 wt%, or 0.5-2 wt%, or 0.7-5 wt%, or 0.7-3 wt%, or 0.7-2 wt%, on an elemental basis excluding carbon. In various embodiments, the FT catalyst material comprises in the range of 1-5 wt% alkali metal, on an elemental basis. For example, in various embodiments, the FT catalyst comprises 1-3 wt%, or 1-2 wt%, or 1.3-5 wt%, or 1.3-3 wt%, or 1.3-2 wt% alkali metal, on an elemental basis excluding carbon. In some embodiments described herein, the FT catalyst comprises 1.5-5 wt% alkali metal, on anelemental basis excluding carbon. For example, in some embodiments the FT catalyst comprises 1.5-3 wt%, or 1.5-2.5 wt%, or 1.5-5 wt%, or 1.5-3 wt%, or 1.5-2.5 wt% alkali metal, on an elemental basis excluding carbon.

[0114] In some embodiments, the alkali metal present in the FT catalyst is one or more of sodium, potassium, rubidium and cesium. In some embodiments as described herein, the alkali metal is one or more of sodium and potassium. For example, in some embodiments as described herein, the alkali metal is sodium. In particularly desirable embodiments, the alkali metal is potassium.

[0115] The particulars of the FT catalyst will depend on the intended use in operation. For example, if it is desired to suppress water-gas shift activity in the FT stage, a relatively low amount of alkali can be used in the FT catalyst, and relatively low FT reaction temperatures can be used; this can be desirable when the rWGS stage provides a high degree of conversion to carbon monoxide. If, however, the rWGS stage provides a lower degree of conversion to carbon monoxide, then it may be desirable to use an increased amount of alkali in the FT catalyst to favor reverse water-gas shift of CO2 to CO in the FT stage. Higher FT reaction temperatures can assist with this -- but at higher temperatures, C5+ selectivity from CO conversion may suffer. In many cases, it may be desirable to balance these effects, selecting an intermediate reaction temperature (e.g., 250-300 °C) and an intermediate alkali promoter level to provide for good C5+ selectivity while still converting some amount of CO2 via reverse water-gas shift in the FT stage (e.g., up to 20% conversion, or up to 10% conversion).

[0116] As with the rWGS catalyst, FT catalysts are typically activated before use, e.g., to provide iron carbide species on an iron-based FT catalyst as described herein. Such activation can be performed prior to contacting the FT catalyst with the FT feed stream as described herein.

[0117] For example, in some embodiments, the FT catalyst is activated by contact with a reducing gas. For example, hydrogen can be an especially suitable gas for activating the FT catalyst, e.g., when the activation is a reduction to metal(O) species. In various embodiments as otherwise described herein, the reducing gas comprises at least a portion of H2 from the shift product stream. For example, in some embodiments, the process further comprises separating at least a portion of H2 of the shift product stream and contacting it with the FT catalyst to activate the FT catalyst. In the process 100 shown schematically in FIG. 1, at least a portion of hydrogen stream 125 is separated from the shift product stream 112 and contacted with the FT catalyst 123 to activate it. In other embodiments, H2 present in the FT feed stream can be used to activate the FT catalyst. As would be understood bythe person of ordinary skill in the art, activation temperatures can vary depending on the FT catalyst used. Accordingly, the person of ordinary skill in the art would be able to select an appropriate temperature for activating the FT catalyst, e.g., in the range of 200-400 °C.

[0118] In various embodiments, the FT catalyst is activated by contact with H2 and CO. This can be especially suitable when the activation provides conversion to carbide, e.g., as for many iron-based catalysts including those as described herein. In various embodiments as otherwise described herein, the reducing gas comprises at least a portion of H2 and CO from the shift product stream. For example, in some embodiments, the process further comprises separating at least a portion of H2 and at least a portion of CO of the shift product stream and contacting it with the FT catalyst to activate the FT catalyst. In the process 200 shown schematically in FIG. 2, at least a portion of H2 and CO stream 227 is separated from the shift product stream 212 and contacted with the FT catalyst 223 to activate the FT catalyst. In other embodiments, F^and CO present in the FT feed stream can be used to activate the FT catalyst during an induction period. Activation temperatures can vary, e.g., in the range of 200-400 °C. It can be desirable to perform activation such that some degree of iron oxide remains in the catalyst, e.g., in the form of FesO4, as such iron oxides are understood to provide water-gas shift activity. Accordingly, in various embodiments, the iron-based FT catalyst, under contact with the FT feed stream, has at least 5 atom% of its iron in the form of iron oxide, e.g., at least 10 atom%. In various embodiments, the ironbased FT catalyst, under contact with the FT feed stream, has in the range of 5-60 atom% of its iron in the form of iron oxide, e.g., 10-60 atom%, or 5-40 atom%, or 10-40 atom%, or 5-30 atom%, or 10-30 atom%. The amount of iron that is in the form of oxide is determined by Mbssbauer spectroscopy, and as such is expressed as an atomic fraction of iron in the form of oxide of the total iron species visible to Mbssbauer spectroscopy.

[0119] In various embodiments, at least 30 atom% of the oxidic iron of the carbided Fischer-Tropsch catalyst material is in the form of FesC . The present inventors note that this partially-reduced oxide has especially good activity as a reverse water-gas shift catalyst. In various embodiments, at least 40 atom% of the oxidic iron of the carbided Fischer- Tropsch catalyst material is in the form of FesC , e.g., at least 50 atom%. In various embodiments, at least 60 atom% of the oxidic iron of the carbided Fischer-Tropsch catalyst material is in the form of FesC , e.g., at least 70 atom%. The person of ordinary skill in the art can select carbiding conditions, particularly with respect to conditions under which the material is reduced, to provide a desired amount of FesC . The amount of oxidic iron present as of FesC is determined using Mbssbauer spectroscopy.

[0120] Fischer-Tropsch Processes

[0121] As described herein, the process further includes contacting the FT feed stream with an iron-based FT catalyst at a temperature and at a pressure to conduct the FT process. The person of ordinary skill in the art will select appropriate reaction conditions in conjunction with the particular feed and catalyst used to provide desired FT processes. In some embodiments as described herein, the temperature for the FT process is in the range of 180-400 °C. For example, in various embodiments, the temperature is in the range of 180-350 °C, or 180-300 °C, or 180-250°C, or 180-200°C, or 200-400 °C, or 200-350 °C, or 200-300°C, or 200-250 °C, or 250-400 °C, or 250-350 °C, or 250-300 °C, or 300-400 °C.

[0122] Notably, in many embodiments, the temperature for the rWGS process as described above and the temperature for the FT process as described herein can be relatively close to one another. As noted above, the present inventors have noted that the rWGS catalysts as described herein can provide suitable activity and CO selectivity even at relatively low temperatures. Accordingly, the shift product stream can be provided with a temperature that is suitable for, or at least close to suitable for, the FT process. This can desirably provide for increased process integration. For example, in various embodiments, the temperature for the rWGS process is within 100 °C of the temperature for the FT process, e.g., within 50 °C of the temperature for the FT process, or within 25 °C of the temperature for the FT process.

[0123] However, in other embodiments, the temperature for the rWGS process and the temperature for the FT process are less close to one another. The present inventors have noted that in many cases a desirable temperature for the rWGS process will be significantly greater than a desirable temperature for the FT process. For example, in various embodiments, the temperature for the rWGS process is at least 100 °C greater than the temperature for the FT process, e.g., at least 150 °C greater than the temperature for the FT process, or at least 200 °C greater than the temperature for the FT process. The excess heat in the shift product stream can be used for a number of purposes, for example, to preheat at least part of the shift feed stream or to generate steam for use in generating electricity, as described above.

[0124] In some embodiments as described herein, the pressure for the FT process is in the range of 10-50 barg. For example, in various embodiments, the second pressure is in the range of 20-50 barg, or 25-50 barg, or 10-40 barg, or 20-40 barg, or 25-40 barg, or 10-35 barg, or 20-35 barg, or 25-35 barg, or 20-30 barg.

[0125] The FT process as described herein can be performed at a variety of GHSV (gas hourly space velocity) values, as would be appreciated by the person of ordinary skill in the art. As such, the GHSV for performing the FT process is not particularly limited. Forexample, in some embodiments, the process for performing the FT process is conducted at a GHSV in the range of 1,000 to 2,000,000 IT1. In various embodiments, the process for performing the rWGS process is conducted at a GHSV in the range of 1 ,000 to 1,200,000 I1, or 1 ,000 to 500,000 IT1, or 1,000 to 100,000 IT1, or 5,000 to 1,200,000 IT1, or 5,000 to 500,000 IT1, or 5,000 to 100,000 IT1, or 10,000 to 1,200,000 IT1, or 10,000 to 500,000 IT1, or 10,000 to 100,000 IT1. In various embodiments, the process for performing the FT process is conducted at a GHSV in the range of 1,000 to 50,000 IT1, or 2,000 to 50,000 IT1, or 5,000 to 50,000 IT1, or 10,000 to 50,000, or 1 ,000 to 40,000 IT1, or 2,000 to 40,000 IT1, or 5,000 to 40,000 IT1, or 10,000 to 40,000 IT1, or 1,000 to 30,000 IT1, or 2,000 to 30,000 IT1, or 5,000 to 30,000 IT1, or 10,000 to 30,000 IT1.

[0126] In various embodiments as otherwise desired herein, the contacting of the FT feed stream with the FT catalyst is performed at a CO conversion of at least 40%, e.g., at least 50%.

[0127] The FT process is typically used to make C5+ hydrocarbons, for example, unsubstituted C5+ hydrocarbons (e.g., alkanes and alkenes) and oxygenated C5+ hydrocarbons (e.g., C5+ alcohols, aldehydes, ketones, carboxylic acids). Accordingly, in various embodiments as otherwise described herein, contacting the FT feed stream with an iron-based FT catalyst at a temperature and at a pressure provides an FT product stream comprising C5+ hydrocarbons. For example, contacting the FT feed stream with an ironbased FT catalyst at a temperature and at a pressure provides an FT product stream comprising C5+ hydrocarbons of at least 30%, e.g., at least 50%, or at least 70%. In some embodiments, the selectivity for C5+ alkanes and C5+ alcohols is at least 30%, e.g., at least 50%, or at least 70%.

[0128] Additional components may be present in the FT product stream. For example, in some embodiments, the FT product stream includes water, which is another product of the FT reaction. Also present can be one or more light hydrocarbons (i.e. , C1-C4) as a side product. CO and / or H2 can be present, e.g., unreacted from the second feed stream. CO2 or other inerts as described herein can also be present. Such components of the FT product stream can be separated and / or recycled in various manners.

[0129] As depicted in FIG. 1 and FIG. 2, the integrated process can be conducted in two separate reactors, where the contacting of the shift feed stream with the rWGS catalyst is performed in a first reactor 110 or 210, and the contacting of the FT feed stream with the iron-based FT catalyst is performed in a second reactor 210 or 220, respectively. In other embodiments as otherwise desired herein, the integrated process as described herein can be conducted in a single reactor, e.g., as depicted in FIG. 3, where the contacting of the shiftfeed stream with the rWGS catalyst and the contacting of the FT feed stream with the ironbased FT catalyst are performed in the same reactor (e.g., in separate beds such as in a stacked-bed configuration).

[0130] As described herein, the process further includes separating the FT product stream to provide a first separated FT product stream. This is shown schematically in FIG.3. In the embodiment of FIG. 3, the rWGS catalyst 313 and the FT catalyst 323 are provided in separate beds in the same reactor. Thus, the first reaction zone 310 is a volume of the reactor 305 that includes the bed 314 containing the rWGS catalyst 313, and the second reaction zone 320 is a volume of the reactor 305 that includes the bed 324 containing the FT catalyst 323. Shift feed stream 311 is contacted with the rWGS catalyst 313 to provide shift product stream 312, which is passed directly as the FT feed stream 321 to the FT catalyst 323 to provide FT product stream 322. Here, the process also optionally includes separating at least a portion of water (e.g., at least 50%, at least 75%, or at least 90%) from the FT product stream 322 to provide water-containing stream 334.

[0131] In various embodiments, the first separated product stream comprises at least 80 wt% of the C5+ hydrocarbons of the FT product stream, and at least 80 wt% of the water of the FT product stream.

[0132] Light hydrocarbons, while often not a desired portion of an FT product to be used as a fuel or a lubricant, can themselves be useful for a number of purposes. Accordingly, in various embodiments, the separation of the FT product stream further provides a second separated product stream comprising C1-C4 hydrocarbons of the FT product stream. The light hydrocarbon stream can, for example, be recycled to the shift feed stream or the FT feed stream. For example, in the process 200 of FIG. 2, light hydrocarbons can be provided as part of the recycle stream 236, which becomes part of the FT feed stream 221. In the process 300 of FIG. 3, light hydrocarbons can be provided as part of the recycle stream 336, which becomes part of the shift feed stream 311. In the process 400 of FIG. 4, light hydrocarbons are recycled via recycle stream 442 to shift feed stream 411.

[0133] In various embodiments, the second separated product stream comprises at least 80 wt% of C1-C4 hydrocarbons of the FT product stream, and at least 80 wt% of CO, CO2 and H2 of the FT product stream. In some embodiments, the separation of the FT product stream further provides a third separated product stream comprising at least 80 wt% of CO, CO2 and H2 of the FT product stream. Accordingly, in some embodiments, at least a portion of the third separated product stream is recycled to the shift feed stream.

[0134] There are other uses for the light hydrocarbon stream. For example, in some embodiments, the process further comprises oxidizing at least a portion of the light hydrocarbon stream to provide a CO- and / or CO2-containing partial oxidation (pOX) stream, and including at least a portion of the pOX stream in the shift feed stream and / or the FT feed stream. An example of such a process is shown schematically in FIG. 4, in which the process 400, the shift feed stream 411 , the shift product stream 412, the rWGS catalyst 413, the FT feed stream 421 , the FT product stream 422, and the FT catalyst 423 can be as otherwise described herein. Here, the process includes oxidizing at least a portion of the light hydrocarbon stream 450 in a partial oxidation reaction zone 452 to provide a CO- and / or CO2 containing pOX stream, and including at least a portion of the pOX stream 454 stream in the shift feed stream 411 and / or the FT feed stream 421.

[0135] Moreover, the light hydrocarbon stream can be burned to provide heat energy, which can be used to heat various process streams, or to generate electricity. Accordingly, in various embodiments, the process includes burning at least a portion of the light hydrocarbon stream to provide energy, e.g., heat energy or electrical energy. For example, in the process 400 of FIG. 4, a portion of light hydrocarbon stream 450 is burned in a power generation zone (here, in an electrical generator 470), to generate electricity stream 472. In various embodiments, the heat energy may be used to provide the needed heat duty for the rWGS process. For example, in the process 400 of FIG. 4, a portion of the light hydrocarbon stream 450 is burned in a power generation zone (here, in a heat generator 480), to generate heat stream 482. The heat stream 482 is conducted to a heat exchange zone 490 to heat the shift feed stream 411.

[0136] As with the first separated product stream, heat can be exchanged from the second separated product stream to provide heat to, for example, a feed stream or a steam generation zone. For example, in various embodiments, the process further comprises exchanging heat between at least a portion of the FT product stream and at least a portion of the shift feed stream, thereby cooling at least a portion of the FT product stream and heating at least a portion of the shift feed stream. In process 300 of FIG. 3, heat is exchanged between at least a portion of the FT product stream 322 and shift feed stream 311 in a second heat exchange zone 330, thereby cooling the FT product stream 322 and heating the shift feed stream 311. Of course, heat can also be exchanged from the FT product stream to the FT feed stream. For example, in various embodiments, the process further comprises exchanging heat between at least a portion of the FT product stream and at least a portion of the FT feed stream, thereby cooling at least a portion of the FT product stream and heating at least a portion of the FT feed stream. In process 400 of FIG. 4, heat is exchanged between at least a portion of the FT product stream 422 and the FT feed stream421 in a second heat exchange zone 430, thereby cooling the FT product stream 422 and heating the FT feed stream 421. The person of ordinary skill in the art will appreciate that a wide variety of heat exchangers can be used for this purpose.

[0137] Of course, any excess heat in the FT product stream can be additionally or alternatively used for other purposes. For example, in various embodiments, the process further comprises exchanging heat between at least a portion of the FT product stream and a steam generation zone, thereby cooling at least a portion of the FT product stream and providing heat to the steam generation zone. This is shown in FIG. 3. Here, after heat exchange with the shift feed stream 311 , the FT product stream 322 is conducted to steam generation zone 332 to cool the FT product stream 322 and provide heat to the steam generation zone 332. Steam can be generated from the heat provided, and electricity can be generated from the steam (not shown here).

[0138] It can be desirable to recycle hydrogen from the FT product stream, for example, to the shift feed stream and / or the FT feed stream. For example, in various embodiments, the process includes recycling at least a portion of H2 of the FT product stream to the FT feed stream. For example, in the process of FIG. 2, at least a portion of H2 of the FT product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the FT feed stream 221 via recycle stream 236. In various embodiments, the process includes recycling at least a portion of H2 of the FT product stream to the shift feed stream. For example, in the process of FIG. 3, at least a portion of H2 of the FT product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the shift feed stream 311 via recycle stream 336. In various embodiments, at least 25%, e.g., at least 50% of H2 of the FT product stream is recycled to the shift feed stream or the FT feed stream. In various embodiments, at least 75%, e.g., at least 90% of H2 of the FT product stream is recycled to the shift feed stream or the FT feed stream.

[0139] In some cases, e.g., when H2 is provided to the FT feed stream from an H2 source other than the shift product stream, H2 from the FT product stream can make up most of the H2 of the shift feed stream, e.g., at least 90%, at least 95%, or at least 98% of the H2 in the shift feed stream. This is shown, e.g., in FIG. 4. Here, the primary H2 input to the process is through stream 440, which becomes part of the FT feed stream 421. H2 of the FT product stream is included in recycle stream 442, which becomes part of shift feed stream 411.

[0140] Similarly, it can be desirable to recycle CO of the FT product stream, for example, to the shift feed stream and / or the FT feed stream. For example, in various embodiments, the process includes recycling at least a portion of CO of the FT product stream to the FTfeed stream. For example, in the process of FIG. 2, at least a portion of CO of the FT product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the FT feed stream 221 via recycle stream 236. In various embodiments, the process includes recycling at least a portion of CO of the FT product stream to the shift feed stream. For example, in the process of FIG. 3, at least a portion of CO of the FT product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the shift feed stream 311 via recycle stream 336. In various embodiments, at least 25%, e.g., at least 50% of CO of the FT product stream is recycled to the shift feed stream or the FT feed stream. In various embodiments, at least 75%, e.g., at least 90% of CO of the FT product stream is recycled to the shift feed stream or the FT feed stream.

[0141] In many cases, both CO and H2 of the FT product stream will be recycled.

[0142] Moreover, when one or more inerts are used in the FT process, it can be desirable to recycle them. For example, in various embodiments, the process includes recycling at least a portion of inerts of the FT product stream to the FT feed stream. For example, in the process of FIG. 2, at least a portion of inerts of the FT product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the FT feed stream 221 via recycle stream 236. In various embodiments, the process includes recycling at least a portion of inerts of the FT product stream to the shift feed stream. For example, in the process of FIG. 3, at least a portion of inerts of the FT product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the shift feed stream 311 via recycle stream 336. In various embodiments, at least 25%, e.g., at least 50% of inerts of the FT product stream is recycled to the shift feed stream or the FT feed stream. In various embodiments, at least 75%, e.g., at least 90% of inerts of the FT product stream is recycled to the shift feed stream or the FT feed stream. In various embodiments, a purge stream can be incorporated with the recycle stream to prevent uncontrolled accumulation of inerts in the recycle stream (not shown here).

[0143] Specifically, as CO2 is the carbon source for the rWGS process, it can be especially desirable to recycle CO2 to the shift feed stream. Accordingly, in various embodiments, the process includes recycling at least a portion (e.g., at least 50%, at least 75%, or at least 90%) of CO2 of the FT product stream to the shift feed stream. For example, in the process of FIG. 3, at least a portion of CO2 of the FT product stream (e.g., at least 50%, at least 75%, or at least 90%) can be recycled to the shift feed stream 311 via recycle stream 336.

[0144] In some cases, e.g., when CO2 is provided to the FT feed stream from a CO2 source other than the shift product stream, CO2 from the FT product stream can make upmost of the CO2 of the shift feed stream, e.g., at least 90%, at least 95%, or at least 98% of the CO2 of the shift feed stream. This is shown, e.g., in FIG. 4. Here, the primary CO2 input to the process is through stream 440, which becomes part of the FT feed stream 421. CO2 of the FT product stream is included in recycle stream 442, which becomes part of shift feed stream 411.

[0145] As noted above, the FT process provides an FT product stream that includes C5+ hydrocarbons (e.g., unsubstituted hydrocarbons like alkanes and alkenes, and / or oxygenated hydrocarbons such as alcohols). Accordingly, in various embodiments, one or more products are provided from at least a portion of C5+ hydrocarbons of the FT product stream. The C5+ hydrocarbons can be used as the basis of a variety of fuels, e.g., gasoline, diesel, aviation fuel. Other products, like waxes and lubricants, can also be made. And alkenes and oxygenates can be used as feedstocks in a variety of other processes.

[0146] The person of ordinary skill in the art will use conventional post-processing techniques to convert the C5+ hydrocarbon-containing product to desirable products such as desirable fuels. For example, in various embodiments, the process further includes hydroprocessing at least a portion of C5+ hydrocarbons of the FT product stream. As the person of ordinary skill in the art will appreciate, hydroprocessing is a treatment of the hydrocarbon stream with hydrogen in the presence of a suitable catalyst. A wide variety of hydroprocessing techniques are known, and the person of ordinary skill in the art will apply them accordingly. For example, in the process 300 of FIG. 3, FT product stream 322 is hydroprocessed in hydroprocessing reactor 350, to provide a hydroprocessed product stream 352.

[0147] As noted above, the FT feed stream can be provided substantially from the rWGS product stream, and can be supplemented with one or more of H2, CO and CO2. It may, in some cases, be desirable to supplement with additional H2, as additional H2 can push the water-gas shift equilibrium to favor further conversion of CO2 to CO on the iron-based FT catalyst. However, the C5+ selectivity of the FT process may suffer when adding H2, due to the resulting higher H2 / CO and H2 / CO2 ratios. In this regard, it can be desirable to maintain the molar ratio of H2 / CO no greater than 2, and the molar ratio of H2 / CO2 no greater than 3. Based on this, the person of ordinary skill in the art can select an amount of H2 that provides a desirable trade-off between the boosted conversion of carbon dioxide and carbon monoxide, thereby requiring less recycling of unconverted material back to the rWGS stage on one hand, and making more light gases at the expense of higher hydrocarbons on the other hand.

[0148] As described above, CO2 and H2 are substantial inputs to the claimed processes. Advantageously, the present inventors have recognized that each of these can come from renewable or otherwise environmentally responsible sources.

[0149] CO2 can be captured from the environment generally, or more directly from processes that form CO2 (especially in difficult-to-abate sectors). This can make the eventual hydrocarbon product substantially carbon-neutral or of lower carbon intensity. Accordingly, in some embodiments as described herein, at least a part of the CO2 of the shift feed stream and / or the FT feed stream is from a renewable source. In some embodiments, at least part (e.g., at least 25%, at least 50%, or at least 75%) of the CO2 of the shift feed stream and / or the FT feed stream is from direct air capture. In some embodiments, at least part (e.g., at least 25%, at least 50%, or at least 75%) of the CO2 of the shift feed stream and / or the FT feed stream is from a manufacturing plant such as a bioethanol plant (e.g., CO2 produced fermentation), a steel plant, or a cement plant. Accordingly, the rWGS-FT integrated process as described herein can be not only carbon neutral, but in some cases a net consumer of carbon dioxide. These benefits in particular make the integrated process highly attractive for decarbonizing transportation fuels, for both automotive and aviation sectors, since CO produced in the rWGS reaction can be readily utilized by well-established technologies to synthesize liquid hydrocarbon fuels by FT processes.

[0150] Similarly, H2 can be provided from environmentally-responsible sources. In some embodiments, at least a part of the H2 of the shift feed stream and / or the FT feed stream is from a renewable source. For example, in various embodiments, at least part (e.g., at least 25%, at least 50%, or at least 75%) of the H2 of the shift feed stream and / or the FT feed stream can be so-called “green” hydrogen, e.g., produced from the electrolysis of water operated using renewable electricity (such as wind, solar, or hydro-electric power). In some embodiments, at least part (e.g., at least 25%, at least 50%, or at least 75%) of the H2 of the shift feed stream and / or the FT feed stream may be from a so-called “blue” source, e.g., from a natural gas reforming process with carbon capture. Of course, other sources of H2 can be used in part or in full. For example, in some embodiments, at least part (e.g., at least 25%, at least 50%, or at least 75%) of the H2 of the shift feed stream and / or the FT feed stream is grey hydrogen, black hydrogen, brown hydrogen, pink hydrogen, turquoise hydrogen, yellow hydrogen, and / or white hydrogen.

[0151] The present inventors have noted that electrolysis of water is a desirable way to provide hydrogen to the claimed processes. Accordingly, in some embodiments, the process includes providing at least a portion of H2 to the shift feed stream and / or the FT feed stream by electrolysis of water. In some embodiments, the electrolysis of water is performedusing at least partially electricity from a renewable source, e.g., to provide so-called “green hydrogen.” However, the present inventors have noted that electricity can be generated as part of the claimed process, e.g., using heat exchange from the shift or FT product stream, or by burning light hydrocarbons as described above. In some embodiments, the electrolysis of water is performed using at least partially electricity generated according to the processes as described herein. For example, in the process 200 of FIG. 2, water 262 separated from the shift product stream is electrolyzed in electrolyzer 260, using electricity 264 generated from steam made in the steam generation zone 232 by heat exchange from the shift product stream. H2 generated in the electrolysis is provided via stream 265 to the shift feed stream. In some embodiments, at least a portion of O2 generated in the electrolysis is provided to a partial oxidation reaction zone as described herein.

[0152] The processes described herein can be operated in a wide variety of reactor systems. In some embodiments, the first reaction zone (i.e. , in which the rWGS process is performed) comprises a first reactor in which an rWGS catalyst is disposed, and the second reaction zone (i.e., in which the FT process is performed) comprises a second reactor in which the FT catalyst is disposed. Examples of such processes are shown schematically in FIGS. 2, 3, and 5. In these examples, the process (100, 200, 400) is performed in a reactor system that includes a first reactor (110, 210, 410) in which an rWGS catalyst (113, 213, 413) is disposed, and a second reactor (120, 220, 420) in which the FT catalyst (123, 223, 423) is disposed. The reactors used for the integrated process of the present disclosure as described herein are not particularly limited, and the person of ordinary skill in the art will be able to select an appropriate reactor.

[0153] But other embodiments are possible. In some embodiments as described herein, the contacting of the shift feed stream with the rWGS catalyst is performed in a first reactor bed, and the contacting of the FT feed stream with the iron-based FT catalyst is performed in a second reactor bed. In some embodiments where a first reactor bed and a second reactor bed are used, the rWGS catalyst and the iron-based FT catalyst are separated (i.e., not admixed in the same reactor bed). For example, in some embodiments, the process is performed in a reactor system comprising first catalyst bed in which the rWGS catalyst is disposed, and wherein the second reaction zone comprises a second catalyst bed in which the FT catalyst is disposed. In some embodiments, the first reactor bed and the second reactor bed are disposed within the same reactor. Such a configuration is shown in FIG. 3, in which the rWGS catalyst 313 is disposed in a first catalyst bed 314, and the FT catalyst 323 is disposed in a second catalyst bed 324. Here, the catalyst beds 314 and 324 are in the same reactor, with process gases flowing between them. Such a configurationcan be especially desirable when the temperature for the rWGS process and the temperature for the FT process are relatively close to one another.

[0154] In various embodiments, the process is performed in a reactor system comprising one or more first catalyst containers in which the rWGS catalyst is disposed, and wherein the second reaction zone comprises one or more second catalyst containers in which the FT catalyst is disposed. These can be provided in the same reactor, such as described above with respect to catalyst beds.

[0155] As noted above, the rWGS process and the FT process can be performed under similar conditions. Accordingly, in various embodiments, the rWGS catalyst and the FT catalyst can be provided together in the same catalyst bed, e.g., mixed together. Such an embodiment is shown in FIG. 5. Here, the process 500 is performed in a reactor system that includes a reactor 505 in which the rWGS catalyst 513 and the FT catalyst 523 are mixed together in a single catalyst bed 524. Here, shift feed stream 511 and FT product stream 522 can be substantially as described herein. The shift product stream and the FT feed stream are understood to be the mixture of process gases within the mixed catalysts.

[0156] In the embodiments particularly-described above, separate rWGS and FT catalysts are used, e.g., in separate reactors, in separate regions of the same reactor, or even comingled in the same region of a reactor.

[0157] However, the present inventors also note that there are certain commonalities between the rWGS catalysts and certain FT catalysts as described herein. For example, as the person of ordinary skill in the art would appreciate, manganese is a common modifier used in FT catalysts. The present inventors also note that similar supports can be used for each catalyst.

[0158] Accordingly, in addition to the configurations described above, the present inventors contemplate the provision of a single bifunctional catalyst with both rWGS activity and FT activity. Such a bifunctional catalyst includes both rWGS-active catalyst metal and the FT active catalyst metal in the same body. The person or ordinary skill in the art will appreciate that both the rWGS catalysts and the FT catalysts are supported catalyst, e.g., metal oxide supported catalysts. As such, in various embodiments, the rWGS-active catalyst metals and the FT active catalyst metals can be provided together on the same support to provide a bifunctional catalyst. For example, in some embodiments, the supports of bifunctional catalyst are provided themselves as discrete body of material, e.g., as porous particles, pellets, or shaped extrudates, with the rWGS-active catalyst metals and the FT- active catalyst metals provided thereon to provide a bifunctional catalyst. The rWGS-activecatalyst metals and the FT-active catalyst metals may be homogenous distributed throughout the support or may be distributed in discrete areas throughout the support. However, in other embodiments, the bifunctional catalyst of the disclosure can itself be formed as a layer on an underlying substrate. For example, in some embodiments, the bifunctional catalyst is formed from a layer of rWGS-active catalyst metals and a layer of FT- active catalyst metals on an underlying substrate. The rWGS-active catalyst metals and the FT-active catalyst metals may be homogeneously distributed on the underlying substrate. In other embodiments, the rWGS-active catalyst metals and the FT-active catalyst metals may be in discrete areas on the underlying substrate. The underlying substrate is not particularly limited. It can be formed of, e.g., a metal or metal oxide, and can itself be provided in a number of forms, such as particles, pellets, shaped extrudates, or monoliths.

[0159] The bifunctional catalyst includes a support material, the rWGS-active catalyst metals as described herein, and the FT active catalyst metals as described herein. For example, the bifunctional catalyst includes a support that is a metal oxide support comprising at least one of titanium oxide, zirconium oxide, cerium oxide, or aluminum oxide. The rWGS-active catalyst metals and the FT active catalyst metals are not particularly limited, and the person of ordinary skill in the art would be able to select the appropriate metals. For example, the person or ordinary skill in the art would be able to select an appropriate rWGS active metal as described in Daza et al. “CO2 conversion by reverse water gas shift catalysis: comparison of catalysts, mechanisms and their consequences for CO2 conversion to liquid fuels.” RSC Adv., 2016, 6, 49675-49691; Zhu et al. “Catalytic Reduction of CO2 to CO via Reverse Water Gas Shift Reaction: Recent Advances in the Design of Active and Selective Supported Metal Catalyst.” Transaction of Tianjin University, 2020, 26, 172-187; and Chen et al. “Recent Advances in Supported Metal Catalysts and Oxide Catalyst for the Reverse Water-Gas Shift Reaction.” Front. Chem., 2020, 8, 709. For example, the rWGS active metals may be selected from copper, platinum, palladium, rhodium, rhenium, ruthenium, nickel, gold, and iridium or combinations thereof. Similarly, the person of ordinary skill in the art would be able to select an appropriate FT active metal as described herein. For example, the FT active metal may be selected from iron, rhodium, ruthenium, manganese, or combinations thereof. .

[0160] The ratio of rWGS-active catalyst metals to FT-active catalyst metals in the bifunctional catalyst is not particularly limited, and the person of ordinary skill in the art would be able to select an appropriate ratio. For example, in some embodiments, the ratio of rWGS-active catalyst metals to FT-active catalyst metals in the bifunctional catalyst is at least 0.1:1. In various embodiments, the ratio of rWGS-active catalyst metals to FT-active catalyst metals in the bifunctional catalyst is at least 0.2:1 , or 0.5, or 1 :1.

[0161] Such catalysts can be used in embodiments as described with respect to FIG. 5. The person of ordinary skill in the art will select reaction conditions that provide the appropriate balance of rWGS activity and FT activity.

[0162] One example of a process scheme is shown in FIG. 6. Here, a scheme for an integrated rWGS and iron-FT process is depicted as being performed with two separate, close-coupled reactor units.

[0163] Another example of a process scheme is shown in FIG. 7. Here, the integrated rWGS and iron-FT process are depicted as being performed in a single reactor with stacked beds, with a degree of temperature integration between the processes.

[0164] Notably, the present inventors have determined that there can, in many embodiments of the processes as described throughout this disclosure, be a high degree of temperature and / or pressure integration between the rWGS and iron-FT processes. For example, in various embodiments, the reaction temperature of the iron-FT process is within 100 °C of the reaction temperature of the rWGS process, e.g., within 50 °C. In various embodiments, the reaction pressure of the iron-FT process is within 10 bar of the reaction pressure of the rWGS process, e.g., within 5 bar.

[0165] Additional aspects of the disclosure are provided by the following enumerated embodiments, which may be combined in any number and in any combination that is not logically or technically inconsistent.Embodiment 1. A process for preparing hydrocarbons, the process comprising: contacting a shift feed stream comprising carbon dioxide and hydrogen with a reverse water-gas shift (rWGS) catalyst under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water; providing a Fischer-Tropsch (FT) feed stream comprising at least a portion of the carbon monoxide, hydrogen, and carbon dioxide from the shift product stream, the FT feed stream comprising at least 5 mol% carbon dioxide, the FT feed stream having a molar ratio of carbon dioxide to carbon monoxide of at least 2, e.g., at least 2.5 or at least 3; contacting the FT feed stream with an iron-based FT catalyst, in the substantial absence of a cobalt-based FT catalyst, to form an FT product stream comprising C5+ hydrocarbons, light hydrocarbons, water and carbon dioxide; andseparating the FT product stream to provide a first separated product stream comprising at least 80 wt% of the C5+ hydrocarbons and at least 80 wt% of the water of the FT product stream.Embodiment 2. The process of embodiment 1 , wherein a molar ratio of hydrogen to carbon dioxide in the shift feed stream is in the range of 2-4.Embodiment 3. The process of embodiment 1 or embodiment 2, wherein the rWGS catalyst is a copper-based catalyst.Embodiment 4. The process of embodiment 1 or embodiment 2, wherein the rWGS catalyst comprises a transition metal selected from manganese, copper, zinc, gallium, indium, lanthanum, titanium, niobium, vanadium, zirconium, platinum, palladium, gold, and nickel.Embodiment 5. The process of any of embodiments 1-4, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a temperature in the range of 180- 400 °C, e.g., 250-350 °C.Embodiment 6. The process of any of embodiments 1-5, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a pressure in the range of 10-100 barg, e.g., 15-70 barg, or 20-30 barg.Embodiment 7. The process of any of embodiments 1-4, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a temperature of no more than 400 °C (e.g., 180-400 °C or 180-350 °C) and at a pressure of at least 20 barg (e.g., 20-30 barg).Embodiment 8. The process of any of embodiments 1-7, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of carbon dioxide of no more than 60%, e.g., in the range of 10-60%.Embodiment 9. The process of any of embodiments 1-7, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of carbon dioxide of 5- 35%, e.g., 5-30%, or 5-25%, or 5-20%, or 10-35%, or 10-30%, or 10-25%.Embodiment 10. The process of any of embodiments 1-9, wherein the FT feed stream comprises at least 10 mol% carbon dioxide, e.g., at least 15 mol% carbon dioxide.Embodiment 11. The process of any of embodiments 1-9, wherein the FT feed stream comprises in the range of 5-75 mol% carbon dioxide, e.g., in the range of 5-60 mol%, or 5- 45 mol%.Embodiment 12. The process of any of embodiments 1-9, wherein the FT feed stream comprises in the range of 10-75 mol% carbon dioxide, e.g., in the range of 10-60 mol%, or 10-45 mol%.Embodiment 13. The process of any of embodiments 1-9, wherein the FT feed stream comprises in the range of 15-75 mol% carbon dioxide, e.g., in the range of 15-60 mol%, or 15-45 mol%.Embodiment 14. The process of any of embodiments 1-13, wherein the FT feed stream comprises at least 4 mol% carbon monoxide, e.g., at least 8 mol%, or at least 12 mol%.Embodiment 15. The process of any of embodiments 1-14, wherein the FT feed stream comprises in the range of 4-20 mol% carbon monoxide, e.g., in the range of 4-18 mol%, or 4-16 mol%, or 4-12 mol%.Embodiment 16. The process of any of embodiments 1-14, wherein the FT feed stream comprises in the range of 8-20 mol% carbon monoxide, e.g., in the range of 8-18 mol%, or 8-16 mol%, or 8-12 mol%.Embodiment 17. The process of any of embodiments 1-14, wherein the FT feed stream comprises in the range of 12-20 mol% carbon monoxide, e.g., in the range of 12-18 mol%, or 12-16 mol%.Embodiment 18. The process of any of embodiments 1-17, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is at least 2.5, e.g., at least 3, or at least 3.5 or at least 4.Embodiment 19. The process of any of embodiments 1-17, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is in the range of 2-10, e.g., 2-8 or2-6 or 2-5.Embodiment 20. The process of any of embodiments 1-17, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is in the range of 2.5-10, e.g., 2.5- 8 or 2.5-6 or 2.5-5.Embodiment 21 The process of any of embodiments 1-17, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is in the range of 3-10, e.g., 3-8 or3-6.Embodiment 22. The process of any of embodiments 1-17, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is in the range of 3.5-10, e.g., 3.5- 8 or 3.5-6.Embodiment 23. The process of any of embodiments 1-17, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is in the range of 4-10, e.g., 4-8 or4-7.Embodiment 24. The process of any of embodiments 1-23, wherein the FT feed stream comprises at least 10 mol% hydrogen, e.g., at least 20 mol%, or at least 30 mol%.Embodiment 25. The process of any of embodiments 1-23, wherein the FT feed stream comprises in the range of 10-70 mol% hydrogen, e.g., in the range of 10-60 mol%, or 10-50 mol%, or 20-70 mol%, or 20-60 mol%, or 20-50 mol%, or 30-70 mol%, or 30-60 mol%, or 30- 50 mol%.Embodiment 26. The process of any of embodiments 1-25, wherein a molar ratio of hydrogen to the combination of carbon monoxide and carbon dioxide in the FT feed stream is in the range of 0.5:1 to 6:1 , e.g., 1 :1 to 3:1 , or 1 :1 to 2.5:1.Embodiment 27. The process of any of embodiments 1-25, wherein a molar ratio of hydrogen to the combination of carbon monoxide and carbon dioxide in the FT feed stream is in the range of 1.4:1 to 6:1 , e.g., 1.4:1 to 4:1 , or 1.4:1 to 2:1.Embodiment 28. The process of any of embodiments 1-27, wherein providing the FT feed stream comprises including substantially all the shift product stream in the FT feed stream.Embodiment 29. The process of any of embodiments 1-27, wherein providing the FT feed stream comprises separating the shift product stream to provide a water-rich stream and a water-poor shift product stream, and including at least a portion of the water-poor shift product stream in the FT feed stream.Embodiment 30. The process of any of embodiments 1-29, wherein providing the FT feed stream comprises adding hydrogen to components from the shift product stream.Embodiment 31. The process of any of embodiments 1-30, wherein providing the FT feed stream comprises adding carbon dioxide to components from the shift product stream.Embodiment 32. The process of any of embodiments 1-31, wherein the iron-based FT catalyst is an alkali-promoted iron FT catalyst.Embodiment 33. The process of embodiment 32, wherein the FT iron-based catalyst comprises in the range of 0.2-5 wt% alkali metal, on an elemental basis excluding carbon.Embodiment 34. The process of embodiment 32 or embodiment 33, wherein the alkali is potassium.Embodiment 35. The process of any of embodiments 1-34, wherein the iron-based FT catalyst has at least 5 atom% of its iron in the form of iron oxide, e.g., at least 10 atom%.Embodiment 36. The process of any of embodiments 1-34, wherein the iron-based FT catalyst has in the range of 5-60 atom% of its iron in the form of iron oxide, e.g., 10-60 atom%, or 5-40 atom%, or 10-40 atom%, or 5-30 atom%, or 10-30 atom%.Embodiment 37. The process of any of embodiments 1-36, wherein the contacting of the FT feed stream with the iron-based FT catalyst is performed at a temperature in the range of 180-400 °C, e.g., 250-350 °C.Embodiment 38. The process of any of embodiments 1-37, wherein the contacting of the FT feed stream with the iron-based FT catalyst is performed at a pressure in the range of 10-50 barg, e.g., 20-30 barg.Embodiment 39. The process of any of embodiments 1-38, wherein the contacting of the FT feed stream with the iron-based FT catalyst is performed at a CO conversion of at least 40%, e.g., at least 50%.Embodiment 40. The process of any of embodiments 1-39, wherein the contacting of the shift feed stream with the rWGS catalyst is performed in a first reactor bed, and the contacting of the FT feed stream with the iron-based FT catalyst is performed in a second reactor bed.Embodiment 41 . The process of any of embodiments 1-39, wherein the contacting of the shift feed stream with the rWGS catalyst is performed in a first reactor, and the contacting of the FT feed stream with the iron-based FT catalyst is performed in a second reactor.Embodiment 42. The process of any of embodiments 1-39, wherein the contacting of the shift feed stream with the rWGS catalyst and the contacting of the FT feed stream with the iron-based FT catalyst are performed in the same reactor; e.g., in separate beds such as in a stacked-bed configuration.Embodiment 43. The process of any of embodiments 1-42, wherein the separation of the FT product stream further provides a second separated product stream comprising at least 80 wt% of C1-C4 hydrocarbons of the FT product stream, at least 80 wt% of CO, CO2 and H2 of the FT product stream.Embodiment 44. The process of embodiment 43, further comprising recycling at least a portion of the second separated product stream to the shift feed stream.Embodiment 45. The process of any of embodiments 1-42, wherein the separation of the FT product stream further provides a second separated product stream comprising at least 80 wt% of C1-C4 hydrocarbons of the FT product stream, and a third separated product stream comprising at least 80 wt% of CO, CO2 and H2of the FT product stream.Embodiment 46. The process of embodiment 45, further comprising recycling at least a portion of the second separated product stream to the FT feed stream.Embodiment 47. The process of embodiment 45, further comprising recycling at least a portion of the third separated product stream to the shift feed stream.

[0166] The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings and / or examples making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Thus, before the disclosed processes and devices are described, it is to be understood that the aspects described herein are not limited to specific embodiments, apparatuses, or configurations, and as such can, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and, unless specifically defined herein, is not intended to be limiting.

[0167] The terms “a,” “an,” “the” and similar referents used in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand process of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0168] All processes described herein can be performed in any suitable order of steps unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0169] Unless the context clearly requires otherwise, throughout the description and the claims, the words ‘comprise’, ‘comprising’, and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to”. Words using the singular or plural number also include the plural and singular number, respectively. Additionally, the words “herein,” “above,” and “below” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of the application.

[0170] As will be understood by one of ordinary skill in the art, each embodiment disclosed herein can comprise, consist essentially of or consist of its particular stated element, step, ingredient or component. As used herein, the transition term “comprise” or “comprises” means includes, but is not limited to, and allows for the inclusion of unspecified elements, steps, ingredients, or components, even in major amounts. The transitional phrase “consisting of’ excludes any element, step, ingredient or component not specified. The transition phrase “consisting essentially of” limits the scope of the embodiment to the specified elements, steps, ingredients or components and to those that do not materially affect the embodiment.

[0171] Unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

[0172] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0173] Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and / or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.

[0174] Some embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.

[0175] Furthermore, it is to be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the present invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of example, but not of limitation, alternative configurations of the present invention may be utilized in accordance with the teachings herein. Accordingly, the present invention is not limited to that precisely as shown and described.

Claims

We claim:Claim 1. A process for preparing hydrocarbons, the process comprising: contacting a shift feed stream comprising carbon dioxide and hydrogen with a reverse water-gas shift (rWGS) catalyst in a first reactor bed under conditions sufficient to produce a shift product stream comprising carbon dioxide, hydrogen, carbon monoxide, and water; providing a Fischer-Tropsch (FT) feed stream comprising at least a portion of the carbon monoxide, hydrogen, and carbon dioxide from the shift product stream, the FT feed stream comprising at least 5 mol% carbon dioxide, the FT feed stream having a molar ratio of carbon dioxide to carbon monoxide of at least 2; contacting the FT feed stream with an iron-based FT catalyst in a second reactor bed, in the substantial absence of a cobalt-based FT catalyst, to form an FT product stream comprising C5+ hydrocarbons, light hydrocarbons, water and carbon dioxide; and separating the FT product stream to provide a first separated product stream comprising at least 80 wt% of the C5+ hydrocarbons and at least 80 wt% of the water of the FT product stream.Claim 2. The process of Claim 1 , wherein a molar ratio of hydrogen to carbon dioxide in the shift feed stream is in the range of 2-4.Claim 3. The process of Claim 1 or Claim 2, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a temperature of no more than 400 °C and at a pressure of at least 20 barg.Claim 4. The process of any of Claims 1-3, wherein the contacting of the shift feed stream with the rWGS catalyst is performed at a conversion of carbon dioxide of no more than 60%, e.g., in the range of 10-60%.Claim 5. The process of any of Claims 1-4, wherein the FT feed stream comprises at least 15 mol% carbon dioxide.Claim 6. The process of any of Claims 1-5, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is at least 3.Claim 7. The process of any of Claims 1-6, wherein a molar ratio of carbon dioxide to carbon monoxide in the FT feed stream is in the range of 2.5-6.Claim 8. The process of any of Claims 1-7, wherein a molar ratio of hydrogen to the combination of carbon monoxide and carbon dioxide in the FT feed stream is in the range of 0.5:1 to 6:1.Claim 9. The process of any of Claims 1-8, wherein providing the FT feed stream comprises including substantially all the shift product stream in the FT feed stream.Claim 10. The process of any of Claims 1-8, wherein providing the FT feed stream comprises separating the shift product stream to provide a water-rich stream and a waterpoor shift product stream, and including at least a portion of the water-poor shift product stream in the FT feed stream.Claim 11. The process of any of Claims 1-10, wherein providing the FT feed stream comprises adding hydrogen and / or carbon dioxide to components from the shift product stream.Claim 12. The process of any of Claims 1-11 , wherein the iron-based FT catalyst is an alkali-promoted iron FT catalyst, preferably comprising in the range of 0.2-5 wt% alkali metal, on an elemental basis excluding carbon.Claim 13. The process of any of Claims 1-12, wherein the contacting of the FT feed stream with the iron-based FT catalyst is performed at a temperature in the range of 250-350 °C and / or at a pressure in the range of 10-50 barg.Claim 14. The process of any of Claims 1-13, wherein the contacting of the FT feed stream with the iron-based FT catalyst is performed at a CO conversion of at least 40%, e.g., at least 50%.Claim 15. The process of any of Claims 1-14, wherein the separation of the FT product stream further provides a second separated product stream comprising at least 80 wt% of C1-C4 hydrocarbons of the FT product stream, and at least 80 wt% of CO, CO2 and H2of the FT product stream, and optionally wherein the process further comprises recycling at least a portion of the second separated product stream to the shift feed stream.

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