Iron- and zinc-based fischer-tropsch catalyst materials and processes for making and using same

Abstract

The present disclosure provides a Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 2 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1:2 to 20:1, and the Fischer-Tropsch catalyst material includes at least 10 wt% crystalline ZnFe2O4. Also provided are carbided versions of such catalyst materials, and methods for making and using the same.

Description

IRON- AND ZINC-BASED FISCHER-TROPSCH CATALYST MATERIALS AND PROCESSES FOR MAKING AND USING SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority U.S. provisional application number 63 / 616,374, filed December 29, 2023 and European Patent application number 24166563.7, 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 generally to Fischer-Tropsch catalyst materials, processes of making the same, and Fischer-Tropsch processes using the catalyst materials described herein.2. _ Technical Background

[0003] The conversion of synthesis gas (i.e., a mixture of carbon monoxide and hydrogen, also known as syngas) into hydrocarbons by the Fischer-Tropsch process has been known for decades, but has historically lagged in performance compared to other hydrocarbon synthesis techniques. The growing importance of alternative energy sources has resulted in renewed interest in the Fischer-Tropsch (FT) process as it allows a direct and environmentally- acceptable route to high-quality fuels and feedstock chemicals.

[0004] FT processes are known for producing linear hydrocarbons, as well as oxygenates, that can be useful in fuels and can also serve as valuable feedstock chemicals. The hydrocarbon fuel derived from FT processes is typically better able to meet increasingly stringent environmental regulations compared to conventional refinery-produced fuels, as FT- derived fuels typically have lower contents of sulfur, nitrogen, and aromatic compounds, which contribute to the emission of potent pollutants such as SO2, NOX, and particulates. Alcohols, olefins and other oxygenates obtained may also be used as reagents in other processes, such as in the synthesis of lubricants.

[0005] Currently, cobalt-based catalysts are the primary type of catalysts used in FT processes; they generally yield linear paraffins as primary hydrocarbon products. Iron-based catalyst materials are also known, and can be lower in cost compared to cobalt-based catalyst materials. Iron-catalysed FT typically produces as part of the hydrocarbon product a significant amount of long-chain oxygenates and long-chain a-olefins, which in many cases are desirable products. Moreover, in contrast to cobalt, iron-based catalysts generally exhibit high water gasshift (WGS) activity. The water gas shift reaction competes with the Fischer-Tropsch process by converting CO and H2O to CO2and hydrogen, as shown below:Accordingly, higher WGS activity leads to high CO2yields and lower selectivity of the conversion of feedstock carbon monoxide to C5+ hydrocarbons, which are the generally-desired FT products. While the WGS activity of iron-based FT catalysts can be useful in some cases for syngas feeds having low H2 / CO ratios (e.g., from coal or biomass), the WGS activity undesirably decreases the conversion CO into desired products.

[0006] As such, there is a need to provide improved iron-FT catalysts and iron-based FT processes for use in conversion of carbon monoxide-containing feed streams in FT processes.SUMMARY

[0007] In one aspect, the present disclosure provides a Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and the Fischer-Tropsch catalyst material includes at least 10 wt% crystalline ZnFe2O4.

[0008] Another aspect of the present disclosure provides a process of making a Fischer- Tropsch catalyst material, the process comprising: providing one or more first liquids each comprising one or more iron-containing and / or one or more zinc-containing compounds dissolved in one or more first solvents; contacting the one or more first liquids with precipitating ions in the presence of alkali metal ions to provide an alkali-containing precipitate and a supernatant; isolating the alkali-containing precipitate from the supernatant; optionally, washing the isolated precipitate with a washing liquid to reduce concentration of alkali metal thereof; and calcining the isolated precipitate to provide the Fischer-Tropsch catalyst material.

[0009] Another aspect of the present disclosure provides a process of making a Fischer- Tropsch catalyst material, the process comprising:providing one or more first liquids each comprising one or more iron-containing and / or one or more zinc-containing compounds dissolved in one or more first solvents; contacting the one or more first liquids with precipitating ions in the substantial absence of alkali metal ions to provide a substantially alkali-free precipitate and a supernatant; isolating the substantially alkali-free precipitate from the supernatant; optionally, adding alkali metal ions to the substantially alkali-free precipitate in order to provide an alkali-containing precipitate; and calcining the isolated precipitate to provide the Fischer-Tropsch catalyst material.

[0010] Another aspect of the present disclosure provides a catalyst material made by a process as described herein.

[0011] Another aspect of the present disclosure provides a carbided Fischer-Tropsch catalyst material, e.g., a Fischer-Tropsch catalyst material as described herein in a carbided form.

[0012] Another aspect of the present disclosure provides a carbided Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in the form of iron carbide.Such materials can be made, e.g., by the carbiding of the ZnFe204-containing catalyst materials described herein.

[0013] Another aspect of the present disclosure provides a process for providing a carbided Fischer-Tropsch catalyst material as described herein, the process comprising: providing a Fischer-Tropsch catalyst material as described herein (e.g., made by a process as described herein); optionally, treating the Fischer-Tropsch catalyst material with a reducing gas stream comprising hydrogen for a time and at a temperature sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in metallic form; and thentreating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide (e.g., carbon monoxide), at a temperature of at least 180 °C for a time sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in a carbided form (e.g., in the range of 5 to 20 hours).

[0014] Another aspect of the present disclosure provides a process for performing a Fischer-Tropsch process, the process comprising providing a carbided Fischer Tropsch catalyst material as described herein (e.g., or made by a process described herein); contacting at a reaction temperature and at a pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2and CO to provide a product stream comprising C5+ hydrocarbons.BRIEF DESCRIPTION OF FIGURES

[0015] The accompanying drawings are included to provide a further understanding of the processes 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.

[0016] FIG. 1 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0017] FIG. 2 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0018] FIG. 3 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0019] FIG. 4 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0020] FIG. 5A is a graph carbon number versus mass% per carbon number of the waxes obtained from catalysts as described herein.

[0021] FIG. 5B is a picture of waxes obtained from catalysts as described herein.

[0022] FIG. 6 is an X-ray diffraction (XRD) pattern of a catalyst material as described herein.

[0023] FIG. 7 is an XRD pattern of a catalyst material as described herein.

[0024] FIG. 8 is a set of Mossbauer spectra of a catalyst as described herein.

[0025] FIG. 9 is a set of Mossbauer spectra of a catalyst as described herein.DETAILED DESCRIPTION

[0026] The present inventors have determined that there is a need to reduce the WGS activity of iron-based catalysts in order to provide better CO-to-C5+ conversion in Fischer- Tropsch processes. The present inventors note that cobalt is expensive and relatively scarce, and that iron is abundant and cheap, and thus that iron-based Fischer-Tropsch catalysts can advantageously be more economical and sustainable then cobalt-based Fischer-Tropsch catalysts. However, iron-based Fischer-Tropsch catalysts suffer from high WGS activity, leading to substantial carbon loss during the Fischer-Tropsch process. The present disclosure relates, inter alia, to improved iron-based Fischer-Tropsch catalysts and iron catalyzed Fischer- Tropsch processes having relatively low WGS activity.

[0027] The present inventors have found that limiting the amount of alkali metal and copper in the catalyst can decrease both WGS activity (i.e . , CO2selectivity) and C1-C4 selectivity while increasing C5+ selectivity to provide catalysts that can generally mimic cobalt-based Fischer- Tropsch catalyzed processes. Additionally, the present inventors have found that this selectivity for C5+ hydrocarbons with iron-based catalysts can be accomplished at relatively low Fischer- Tropsch reaction temperatures. Further, by increasing the H2 / CO ratio to approaching and even greater than 2:1 , the WGS activity of the iron-based catalyst can be further suppressed.Accordingly, the present disclosure provides iron-based Fischer-Tropsch catalysts with low WGS activity, processes of making the same, and Fischer-Tropsch processes using the same with better carbon recovery in desirable C5+ products.

[0028] Fischer-Tropsch Catalyst Materials

[0029] As described above, the present inventors have developed iron-based Fischer- Tropsch catalyst materials that can advantageously provide relatively low WGS activity when used in Fischer-Tropsch syntheses. Thus, in one aspect, the present disclosure provides a Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon, no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and wherein the Fischer-Tropsch catalyst material includes at least10 wt% crystalline ZnFe2O4. These catalyst materials can be synthesized, stored and transported, e.g., as oxidic materials, as is common for catalyst materials. As the person of ordinary skill in the art will appreciate, during Fischer-Tropsch synthesis the active catalytic species is actually iron carbide -- but regardless of form the ZnFe204-containing catalyst materials described here can provide relatively low water-gas shift activity together with a suite of other desirable properties when carbided (e.g., in situ in a Fischer Tropsch reactor, especially when carbided at high temperature) and used in Fischer-Tropsch synthesis .

[0030] Amounts of various atomic species as described herein are determined using inductively coupled plasma mass spectrometry (“ICP”). As the person of ordinary skill in the art will appreciate, ICP can detect most elements, but is blind to hydrogen, nitrogen and oxygen. Accordingly, amounts determined by ICP that are quantified “on an elemental basis” are determined with respect to amounts of ICP-measurable elements, i.e. , excluding hydrogen, oxygen and nitrogen. Carbon is detectable by ICP. But in order to maintain consonance between various amounts of materials in various catalyst states, amounts of various atomic species in catalyst materials can also be quantified “on an elemental basis exclusive of carbon,” i.e., determined with respect to amounts of ICP-measurable elements, excluding hydrogen, oxygen, nitrogen and carbon. Quantifications are made without reference to the form in which the atomic species are present (e.g., oxide, metal, carbide, etc.). Measurements can be most conveniently performed on oxidic materials after initial synthesis and carbiding.

[0031] The Fischer-Tropsch catalyst materials described herein (e.g., whether ZnFe2O4- containing or in a carbided form) comprise iron, e.g., in an amount of at least 10 w% on an elemental basis exclusive of carbon. 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 like a zinc ferrite (ZnFe2O4), or single metal oxides like Fe2O3, FeO and Fe3O4), a metal carbide, a metal halide, or a combination thereof. Iron can be provided in a variety of amounts. For example, in various embodiments as described herein, the Fischer- Tropsch catalyst material comprises at least 15 wt% iron, at least 20 wt% iron, or at least 25 wt% iron, on an elemental basis exclusive of carbon. In various embodiments as described herein, the Fischer-Tropsch catalyst material comprises at least 30 wt% iron, at least 35 wt% iron, or at least 40 wt% iron, on an elemental basis exclusive of carbon.

[0032] Along with iron, the Fischer-Tropsch catalyst materials described herein (e.g., whether ZnFe204-containing or in a carbided form) also include zinc in an amount of at least 3 wt%, on an elemental basis exclusive of carbon. The zinc may be present in the catalyst in avariety of forms; most commonly, zinc is principally present as metal, metal oxide (including a mixed metal oxide like zinc ferrite, or a single metal oxide like ZnO), or a combination thereof. Zinc can likewise be provided in a variety of amounts. For example, in various embodiments as described herein, the Fischer-Tropsch catalyst material comprises at least 5 wt% zinc, at least 7 wt% zinc, or at least 10 wt% zinc, on an elemental basis exclusive of carbon. In various embodiments as described herein, the Fischer-Tropsch catalyst material comprises at least 12 wt% zinc, at least 15 wt% zinc, at least 17 wt% zinc, or at least 20 wt% zinc, on an elemental basis exclusive of carbon.

[0033] The Fischer-Tropsch catalyst materials described herein (e.g., whether ZnFe2O4- containing or in a carbided form) do not contain high amounts of copper. When high amounts of copper are present in the material, the selectivity of the ultimately carbided material for water- gas shift processes undesirably increases. As described above, in some embodiments as described herein, the Fischer-Tropsch catalyst material includes no more than 0.1 wt% copper, on an elemental basis exclusive of carbon. For example, in various embodiments as described herein, the Fischer-Tropsch catalyst material comprises no more than 0.05 wt% copper, no more than 0.01 wt% copper, no more than 0.005 wt% copper, or no more than 0.001 wt% copper, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer-Tropsch catalyst material is essentially free of copper.

[0034] However, the present inventors note that having some copper present can help to convert metallic iron into carbided form. As such, the present inventors have found that having small amounts of copper in the Fischer-Tropsch catalyst material can be beneficial as long as it does not unduly increase the WGS activity of the as-carbided Fischer-Tropsch catalyst material. The copper may be present in the Fischer-Tropsch catalyst material in a variety of forms; most commonly, copper is principally present as metal, metal halide, metal oxide, or a combination thereof. For example, in various embodiments as described herein, the Fischer-Tropsch catalyst material comprises 0.005-0.5 wt%, 0.01-0.5 wt%, or 0.02-0.5 wt%, or 0.05-0.5 wt%, or 0.07-0.5 wt%, or 0.1-0.5 wt% copper, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer-Tropsch catalyst material comprises 0.005-0.3 wt% copper, on an elemental basis exclusive of carbon. For example, in various embodiments, the Fischer-Tropsch catalyst material comprises 0.01-0.3 wt%, or 0.02-0.3 wt%, or 0.05-0.3 wt%, or 0.07-0.3 wt%, or 0.1-0.3 wt% copper, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer-Tropsch catalyst material comprises 0.005-0.2 wt% copper, on an elemental basis exclusive of carbon. For example, in variousembodiments, the Fischer-Tropsch catalyst material comprises 0.01-0.2 wt%, or 0.02-0.2 wt%, or 0.05-0.2 wt%, or 0.07-0.2 wt%, or 0.1-0.2 wt% copper, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer-Tropsch catalyst material comprises 0.005-0.15 wt% copper, on an elemental basis exclusive of carbon. For example, in various embodiments, the Fischer-Tropsch catalyst material comprises 0.01-0.15 wt%, or 0.02- 0.15 wt%, or 0.05-0.15 wt%, or 0.07-0.15 wt% copper, on an elemental basis exclusive of carbon.

[0035] The Fischer-Tropsch catalyst material described herein does not include a high amount of alkali metal. As with copper, when high amounts of alkali metal are present in the material, the selectivity for water-gas shift processes increases. Thus, the present inventors have found that as-carbided Fischer-Tropsch catalyst materials without high amounts of alkali metal can retain a low degree of conversion of CO to CO2in a Fischer-T ropsch process. As such, the Fischer-Tropsch catalyst materials as described herein include no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon. The alkali metal may be present in the catalyst in a variety of forms; most commonly, alkali metal is principally present as metal, metal salt such as halide or carbonate, metal oxide, or a combination thereof. For example, in various embodiments as described herein, the Fischer-Tropsch catalyst material comprises no more than 0.4 wt% alkali on an elemental basis exclusive of carbon, e.g., no more than 0.3 wt% alkali. In various embodiments, the Fischer-Tropsch catalyst material comprises no more than 0.2 wt% alkali on an elemental basis exclusive of carbon, e.g., no more than 0.15 wt%.

[0036] However, the present inventors note that the presence of a small amount of alkali metal can be especially desirable. Without intending to be bound by theory, the inventors believe that alkali can provide desirable basicity to the as-carbided Fischer-Tropsch catalyst material. Small amounts of alkali can help improve C5+ selectivity without unduly increasing water-gas shift activity. For example, in various embodiments as described herein, the Fischer- Tropsch catalyst material comprises 0.005-0.5 wt% alkali metal, e.g., 0.01-0.5 wt%, or 0.02-0.5 wt%, or 0.05-0.5 wt%, or 0.07-0.5 wt%, or 0.1-0.5 wt% alkali metal, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer-Tropsch catalyst material comprises 0.005-0.3 wt% alkali metal, on an elemental basis exclusive of carbon. For example, in various embodiments, the Fischer-Tropsch catalyst material comprises 0.01-0.3 wt%, or 0.02-0.3 wt%, or 0.05-0.3 wt%, or 0.07-0.3 wt%, or 0.1-0.3 wt% alkali metal, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer- Tropsch catalyst material comprises 0.005-0.2 wt% alkali metal, on an elemental basisexclusive of carbon. For example, in various embodiments, the Fischer-Tropsch catalyst material comprises 0.01-0.2 wt%, or 0.02-0.2 wt%, or 0.05-0.2 wt%, or 0.07-0.2 wt%, or 0.1-0.2 wt% alkali metal, on an elemental basis exclusive of carbon. In some embodiments as described herein, the Fischer-Tropsch catalyst material comprises 0.005-0.15 wt% alkali metal, on an elemental basis exclusive of carbon. For example, in various embodiments, the Fischer- Tropsch catalyst material comprises 0.01-0.15 wt%, or 0.02-0.15 wt%, or 0.05-0.15 wt%, or 0.07-0.15 wt% alkali metal, on an elemental basis exclusive of carbon.

[0037] In some embodiments, the alkali metal present in the Fischer-Tropsch catalyst material 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.

[0038] As described above, the Fischer-Tropsch catalyst materials of the disclosure include both iron and zinc in an atomic ratio in the range of 1 :2 to 20:1 . For example, in various embodiments as described herein, the atomic ratio of iron to zinc is in the range of 1 :2 to 10:1 , 1 :1.5 to 10:1 , or 1 :1.2 to 10:1 , or 1 :1 to 10:1. In various embodiments as described herein, the atomic ratio of iron to zinc is in the range of 1 :2 to 7:1 , 1 :1 .5 to 7:1 , or 1 :1.2 to 7:1 , or 1 :1 to 7:1 . In various other embodiments as described herein, the atomic ratio of iron to zinc is in the range of 1 :2 to 5:1 , 1 :1.5 to 5:1 , or 1 :1.2 to 5:1 , or 1 :1 to 5:1. In various embodiments as described herein, the atomic ratio of iron to zinc is in the range of 1 :2 to 3:1 , 1 :1 .5 to 3:1 , or 1 :1 .2 to 3:1 , or 1 :1 to 3:1.

[0039] As would be understood by the person of ordinary skill in the art, the iron and zinc may be present in the Fischer-Tropsch catalyst materials described herein in a variety of forms, much as a metal, metal halide, metal carbide, metal oxide (including mixed metal oxide), and combinations thereof. But as described above, in various aspects the Fischer-Tropsch catalyst material as described herein includes at least 10 wt% crystalline ZnFe2O4(i.e. , zinc ferrite). The present inventors have noted that use of a catalyst material that has a significant amount of zinc ferrite can provide a variety of advantages in Fischer-Tropsch processes. Without intending to be bound by theory, the present inventors surmise that the zinc ferrite, when reduced and carbided, provides zinc oxide islands finely dispersed in iron carbide, which can allow for efficient promotion of reactivity at the carbide sites by zinc, and also improve stability of the carbide. In some embodiments as described herein, the Fischer-Tropsch catalyst material includes at least 20 wt% crystalline ZnFe2O4or at least 30 wt%. In some embodiments as described herein, the Fischer-Tropsch catalyst material includes at least 40 wt% crystallineZnFe2O4or at least 50 wt%. In some embodiments as described herein, the Fischer-T ropsch catalyst material includes at least 60 wt% crystalline ZnFe2O4or at least 70 wt%. In some embodiments as described herein, the Fischer-T ropsch catalyst material includes at least 80 wt% crystalline ZnFe2O4or at least 90 wt%.

[0040] In some embodiments as described herein, the crystalline ZnFe2O4has an average crystallite size in the range of 5-25 nm. In some embodiments as described herein, the crystalline ZnFe2O4has an average crystallite size in the range of 5-20 nm, e.g., 5-15 nm, or 5- 10 nm. In some embodiments, the crystalline ZnFe2O4has an average crystallite size in the range of 8-20 nm, e.g., 8-15 nm, or 8-12 nm. In some embodiments, the crystalline ZnFe2O4has an average crystallite size in the range of 10-20 nm, e.g., 10-15 nm, or 10-13 nm.

[0041] The amount of crystalline ZnFe2O4and the crystallite size may be measured by Powder XRD with Rietvald analysis. Accordingly, amounts of crystalline ZnFe2O4(and any other crystalline species quantified via XRD) are quantified as a weight percentage of total materials quantifiable by XRD (i.e., crystalline or otherwise ordered materials).

[0042] As would be understood by the person of skill in the art, at least some of the zinc present in various catalyst materials described herein is in the form of crystalline ZnFe2O4. In some embodiments as described herein, at least 50 atom% of the zinc is in the form of crystalline ZnFe2O4. For example, in various embodiments as described herein, at least 60 wt%, or at least 70 wt%, of the zinc is in the form of crystalline ZnFe2O4. Similarly, in various catalyst materials as described herein, at least some of the iron present in various catalyst materials described herein is in the form of crystalline ZnFe2O4. In some embodiments as described herein, at least 50 atom% of the iron is in the form of crystalline ZnFe2O4. For example, in various embodiments as described herein, at least 60 wt%, or at least 70 wt%, of the iron is in the form of crystalline ZnFe2O4. The person of ordinary skill in the art can, based on the present disclosure, select relative amounts of zinc and iron along with appropriate calcining conditions to provide a high degree of crystalline ZnFe2O4.

[0043] In some embodiments as described herein, the Fischer-T ropsch catalyst material is in substantially oxidic form (i.e., a substantially non-metallic, non-carbided form). As described above, the oxidic form is the result of calcining, and can be especially convenient for storage and transport. As such, in various embodiments as described herein, the Fischer-Tropsch catalyst material is in a substantially non-metallic, non-carbide form. For example, in various embodiments as described herein, the iron, zinc, and alkali metal are substantially present as metal oxides (e.g., with a small amount of metal halide). Such materials can be the result of theprecipitation, drying and calcining processes as described herein. The person of ordinary skill in the art will appreciate that oxidic catalyst materials such as these can be activated by carbiding to provide active catalyst materials for use in Fischer-Tropsch processes.

[0044] In various embodiments as described herein, the Fischer-Tropsch catalyst material (whether in oxidic, reduced, or carbided form, see below) is an unsupported catalyst material. As such, in some embodiments as described herein, at least 90 wt% of the Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (if present), and copper (if present), as determined by ICP, on an elemental basis exclusive of carbon. For example, in various embodiments as described herein, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, or at least 99.8 wt% of the Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (if present), and copper (if present), on an elemental basis exclusive of carbon.

[0045] In some other embodiments as described herein, the Fischer-Tropsch catalyst material (whether in oxidic, reduced, or carbided form, see below) further comprises a support that supports the iron and zinc and, if present, alkali metal and / or copper. As such, in some embodiments as described herein, at least 90 wt% of the Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (i.e. , if present), copper (if present), and the support, as determined by ICP, on an elemental basis exclusive of carbon. For example, in various embodiments as described herein, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, or at least 99.8 wt% of the Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (i.e., if present), copper (i.e., if present), and the support, on an elemental basis exclusive of carbon. The support itself can be provided as discrete bodies of material, e.g., as porous particles, pellets or shaped extrudates, with iron, zinc, and alkali metal, and / or copper (if present), supported to provide the Fischer-Tropsch catalyst material. The support can also be provided as a binder that binds together particles containing iron and zinc. However, in other embodiments, the support can be provided as a monolithic material, e.g., an extrudate. In various embodiments, the support is formed from a refractory oxide. Of course, as would be understood by the person of ordinary skill in the art, other materials may be possible.

[0046] The person of ordinary skill in the art will appreciate that the Fischer-Tropsch catalyst materials of the disclosure 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 reactor, a fluid bed reactor, a bubble column reactor, a so-called CANS reactor.

[0047] Processes for Making Fischer-Tropsch Catalyst Materials

[0048] As described above, the present disclosure also provides processes for making a Fischer-Tropsch catalyst material (e.g., as described herein). Two particular precipitation-based processes for making catalyst materials are provided in detail in this disclosure: one that has alkali present during the precipitation, and one that uses post-precipitation impregnation of alkali metal. Substantially alkali-free materials can be made, e.g., by using additional washing to further reduce the amount of alkali, or by simply omitting alkali impregnation. Materials containing copper can be similarly made; in some situations, copper species can be coprecipitated as part of the precipitated material, instead of impregnated in a later step.

[0049] One process includes providing one or more first liquids each comprising one or more iron-containing and / or one or more zinc-containing compounds dissolved in one or more first solvents; contacting the one or more first liquids with precipitating ions in the presence of one or more alkali metal ions to provide an alkali-containing precipitate and a supernatant; isolating the alkali-containing precipitate from the supernatant; optionally, washing the isolated precipitate with a washing liquid to reduce concentration of alkali metal thereof; and calcining the isolated precipitate to provide the Fischer-Tropsch catalyst material. Here, the precipitation is performed in the presence of alkali metal ions. Without intending to be bound by theory, the present inventors surmise that while the alkali metal ions may not themselves substantially precipitate, the alkali metal-containing supernatant wets the precipitate sufficiently to provide significant alkali content to the precipitate. If necessary, this can be reduced to a desired low level (including substantially no alkali) by the washing with the washing liquid.

[0050] As described above, the one or more first liquids include one or more iron-containing compounds and / or one or more zinc-containing compounds dissolved in one or more first solvents. As the person of ordinary skill in the art will appreciate, these metal species are conveniently provided in the same liquid. As such, in some embodiments as described herein, the process includes providing a first liquid comprising one or more iron-containing compounds and one or more zinc-containing compounds dissolved in a first solvent. However, other schemes are possible. For example, in other embodiments as described herein, the process includes providing more than one first liquids, wherein a first liquid comprises one or more iron- containing compounds and another first liquid comprises zinc-containing compounds; these can be combined with precipitating ions by simultaneous addition. In cases where multiple first liquids are used, the first solvents thereof are desirably miscible with one another.

[0051] The iron-containing and zinc-containing compounds are not particularly limited and the person of ordinary skill in the art would be able to choose appropriate compounds that aresoluble in the first solvent(s). For example, in some embodiments of the disclosure as described herein, the iron-containing compounds and zinc-containing compounds may be selected from metal salts (e.g., nitrates and acetates). The first solvent(s) are also not particularly limited and the person of ordinary skill in the art would be able to choose an appropriate solvent in which the iron-containing compounds and zinc-containing materials are soluble. As the person of ordinary skill in the art will appreciate, a convenient choice for the solvent(s) of the first liquid is water. Other aqueous systems can also be used; an aqueous solvent including a co-solvent such as ethanol may be desirable in some cases. And in some cases, substantially non-aqueous solvents can be used, e.g., one or more of ethanol, isopropanol and acetone, optionally together with ethylene glycol to improve dispersion. As would be understood by the person of skill in the art, the iron-containing and zinc-containing compounds may be provided in amounts in the one or more first liquids to provide the Fischer- Tropsch catalyst material with desired proportions of zinc and iron as described herein.

[0052] The person of ordinary skill in the art will provide the one or more first liquids at a desirable pH at which the iron and zinc compounds remain soluble. For example, in various embodiments, each of the one or more first liquids has a pH of no greater than 7.

[0053] The one or more first liquids are contacted with precipitating ions in the presence of one or more alkali metal ions to provide an alkali-containing precipitate. As the person of ordinary skill in the art will appreciate, this can be conveniently performed by addition of a solution of precipitating ions into a first liquid that includes both the zinc and iron compounds; addition of one or more first liquids into a solution of precipitating ions; or combination of one or more first liquids with a solution of precipitating ions in a separate vessel. The alkali ions can provided, e.g., as a salt of a non-precipitating ion; in the solution of precipitating ions, e.g., as a counterion to precipitation ions; or dissolved in a separate liquid.

[0054] The person of ordinary skill in the art can select desirable precipitating ions. In various embodiments, the precipitating ions are carbonate ions and / or hydroxide ions. The precipitating ions can be provided by use of an alkali metal-containing base to provide both precipitating ions and alkali ions, e.g., an alkali carbonate or an alkali hydroxide. In some embodiments, a combination with a non-metal containing base, e.g., ammonium carbonate or ammonium hydroxide, can be used to provide the alkali-containing precipitate with a desired level of alkali without the need for washing. As an alternative, a non-metal containing base can be used to provide substantially all the precipitating ions, with a separate alkali metal salt (e.g., as a nitrate or an acetate) providing the alkali metal.

[0055] As the person of ordinary skill in the art will appreciate, it can be desirable to perform the precipitation at a desirable alkaline pH. For example, in various embodiments, the contacting of the one or more first liquids with the precipitating ions is performed at precipitation pH in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9- 12, or 9-11 , or 9-10.. It can be desirable to maintain the pH of the precipitation within certain alkaline pH values. For example, in various embodiments, the process further comprises maintaining the pH of the contacting step at an alkaline pH, for example, in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9-12, or 9-11 , or 9-10. The pH of the contacting can be maintained, for example, by controlling a rate of addition of precipitating ions. The person of ordinary skill in the art can otherwise maintain desirable precipitation pH values by maintaining flow rates in the combination of liquids, and, if necessary, addition of additional acid or base components.

[0056] In various embodiments as described herein, the contacting of the one or more first liquids with the precipitating ions is conducted at an elevated temperature. For example, in some embodiments as described herein, the contacting step is conducted at a temperature in the range of 60-100 °C, or 60-90 °C, or 60-80 °C, or 70-100 °C, or 70-90 °C, or 70-80 °C.

[0057] In some embodiments as described herein, the process further comprises aging the precipitate in contact with the supernatant. The aging process is not particularly limited. For example, in some embodiments as described herein, the aging is conducted at a temperature in the range of 60-100 °C, or 60-90 °C, or 60-80 °C, or 70-100 °C, or 70-90 °C, or 70-80 °C. In some embodiments as described herein, the aging is conducted for a time in the range of 1-5 hours, or 1-4 hours or 1-2 hours.

[0058] The alkali-containing precipitate is then isolated from the supernatant. A variety of methods can be used in the isolation, including filtration, centrifugation, and settling and decanting.

[0059] In some embodiments, the amount of alkali metal present in the contacting step is sufficient to provide the isolated precipitate with a desired low level of alkali metal. However, in other cases, washing the isolated precipitate with a washing liquid can be performed to reduce the alkali content thereof. The washing process is not particularly limited. In some embodiments as described herein, washing the isolated precipitate is repeated until a desired level of alkali metal is provided to the Fischer-Tropsch catalyst material. In some embodiments as described herein, the process includes repeating the washing step at least twice (e.g., atleast three times or at least four times). The washing liquid is also not particularly limited and the person of ordinary skill in the art would be able to choose an appropriate liquid. For example, in some embodiments of the disclosure as described herein, the washing liquid is water. However, the present inventors note that the high surface tension of the residual water from the washing step can lead to pores collapsing during the subsequent drying step. As such, it can sometimes be advantageous to use a non-aqueous liquid, particularly in the final washing steps, to obtain catalyst materials with larger surface area and pore volume. For example, in some embodiments as described herein, the washing liquid is a non-aqueous liquid (e.g., ethanol). In some embodiments, the washing liquid across all washing steps is one or more of water or a non-aqueous liquid, or a combination thereof.

[0060] The isolated precipitate, whether washed or not, can then be dried, for example, at an elevated temperature for a drying time. The person of ordinary skill in the art would be able to select appropriate drying apparatuses and conditions. 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. However, a separate drying operation is not necessary in all cases; in some embodiments, volatiles of the supernatant and / or aqueous washing liquids evaporate at a beginning stage of the calcining.

[0061] As noted above, process further includes calcining the precipitate to provide the Fischer-Tropsch catalyst material. The calcining step will typically not only convert various metallic species to oxide forms, it will also form a substantial amount of ZnFe2O4. In some embodiments of the present disclosure as described herein, calcining the precipitate is conducted 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 200-600 °C, or 300-600 °C, or 100-500 °C, or 200-500 °C, or 300-500 °C. The person of ordinary skill in the art can select calcining conditions to provide a desired high degree of ZnFe2O4as otherwise described herein.

[0062] In alternative process for providing the Fischer-Tropsch catalyst materials of the disclosure, the precipitation is performed in the substantial absence of alkali metal. To provide an alkali-containing catalyst material, a small amount of alkali metal can be added to the Fischer-Tropsch catalyst material at a later stage. Accordingly, in another aspect of thedisclosure, a process includes providing one or more first liquids each comprising one or more iron-containing and / or one or more zinc-containing compounds dissolved in one or more first solvents; contacting the one or more first liquids with precipitating ions in the substantial absence of alkali metal ions to provide a substantially alkali-free precipitate and a supernatant; isolating the substantially alkali-free precipitate from the supernatant; optionally adding alkali metal ions to the substantially alkali-free precipitate in order to provide an alkali-containing precipitate; and calcining the isolated precipitate to provide the Fischer-Tropsch catalyst material. Here, the precipitation is performed in the substantial absence of alkali metal ions, and a desired low level of alkali ions can be added to the precipitated material in a separate step. This second process can otherwise be performed in a manner similar to that described above for the first process.

[0063] As described above, the one or more first liquids includes one or more iron- containing compounds and / or one or more zinc-containing compounds dissolved in one or more first solvents. As the person of ordinary skill in the art will appreciate, these metal species are conveniently provided in the same liquid. As such, in some embodiments as described herein, the process includes providing a first liquid comprising one or more iron-containing compounds and one or more zinc-containing compounds dissolved in a first solvent. However, other schemes are possible. For example, in other embodiments as described herein, the process includes providing more than one first liquids, wherein a first liquid comprises one or more iron- containing compounds and another first liquid comprises zinc-containing compounds; these can be combined with precipitating ions by simultaneous addition. In cases where multiple first liquids are used, the first solvents thereof are desirably miscible with one another.

[0064] The iron-containing and zinc-containing 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 first solvent(s). For example, in some embodiments of the disclosure as described herein, the iron-containing and zinc-containing compounds may be selected from metal salts (e.g., nitrates and acetates). The first solvent(s) are also not particularly limited and the person of ordinary skill in the art would be able to choose an appropriate solvent in which the iron-containing and zinc-containing materials are soluble. As the person of ordinary skill in the art will appreciate, a convenient choice for the first solvent(s) is water. Other aqueous systems can also be used; a co-solvent such as ethanol may be desirable in some cases. And in some cases, substantially non-aqueous solvents can be used, e.g., one or more of ethanol, isopropanol and acetone, optionally together with ethylene glycol to improve dispersion. Aswould be understood by the person of skill in the art, the iron-containing and zinc-containing compounds may be provided in amounts in the one or more first liquids to provide the Fischer- Tropsch catalyst material with desired proportions of zinc and iron as described herein.

[0065] The person of ordinary skill in the art will provide the one or more first liquids at a desirable pH at which the iron and zinc compounds remain soluble. For example, in various embodiments, each of the one or more first liquids has a pH of no greater than 7.

[0066] The person of ordinary skill in the art can select desirable precipitating ions. In various embodiments, the precipitating ions are carbonate ions and / or hydroxide ions. The precipitating ions can be provided by use of non-metal containing base, e.g., ammonium carbonate or ammonium hydroxide.

[0067] As the person of ordinary skill in the art will appreciate, it can be desirable to perform the precipitation at a desirable alkaline pH. For example, in various embodiments, the contacting of the one or more first liquids with the precipitating ions is performed at precipitation pH in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9- 12, or 9-11 , or 9-10.. It can be desirable to maintain the pH of the precipitation within certain alkaline pH values. For example, in various embodiments, the process further comprises maintaining the pH of the contacting step at an alkaline pH, for example, in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9-12, or 9-11 , or 9-10. The pH of the contacting can be maintained, for example, by controlling a rate of addition of precipitating ions. The person of ordinary skill in the art can otherwise maintain desirable precipitation pH values by maintaining flow rates in the combination of liquids, and, if necessary, addition of additional acid or base components.

[0068] In various embodiments as described herein, the contacting of the one or more first liquids with the precipitating ions is conducted at an elevated temperature. For example, in some embodiments as described herein, the contacting step is conducted at a temperature in the range of 60-100 °C, or 60-90 °C, or 60-80 °C, or 70-100 °C, or 70-90 °C, or 70-80 °C.

[0069] In some embodiments as described herein, the process further comprises aging the precipitate in contact with the supernatant. The aging process is not particularly limited. For example, in some embodiments as described herein, the aging is conducted at a temperature in the range of 60-100 °C, or 60-90 °C, or 60-80 °C, or 70-100 °C, or 70-90 °C, or 70-80 °C. In some embodiments as described herein, the aging is conducted for a time in the range of 1-5 hours, or 1-4 hours or 1-2 hours.

[0070] The substantially alkali-free precipitate is then separated from the supernatant. A variety of methods can be used in the isolation, including filtration, centrifugation, and settling and decanting.

[0071] In various embodiments, the process further comprises washing the isolated precipitate with a washing liquid. Here, too, the washing liquid is also not particularly limited and the person of ordinary skill in the art would be able to choose an appropriate liquid. For example, in some embodiments of the disclosure as described herein, the washing liquid is water. However, the present inventors note that the high surface tension of the residual water from the washing step can lead to pores collapsing during the subsequent drying step. As such, it can sometimes be advantageous to use a non-aqueous liquid, particularly in the final washing steps, to obtain catalyst materials with larger surface area and pore volume. For example, in some embodiments as described herein, the washing liquid is a non-aqueous liquid (e.g., ethanol). In some embodiments, the washing liquid across all washing steps is one or more of water or a non-aqueous liquid, or a combination thereof.

[0072] The isolated precipitate, whether washed or not, can then be dried, for example, at an elevated temperature for a drying time. The person of ordinary skill in the art would be able to select appropriate drying apparatuses and conditions. 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. However, a separate drying operation is not necessary in all cases; in some embodiments, volatiles of the supernatant and / or aqueous washing liquids evaporate at a beginning stage of the calcining.

[0073] As noted above, process further includes calcining the precipitate to provide the Fischer-Tropsch catalyst material. The calcining step will typically not only convert various metallic species to oxide forms, it will also form a substantial amount of ZnFe2O4. In some embodiments of the present disclosure as described herein, calcining the precipitate is conducted 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 200-600 °C, or 300-600 °C, or 100-500 °C, or 200-500 °C, or 300-500 °C. The person of ordinary skill in the art can select calcining conditions to provide a desired high degree of ZnFe2O4as otherwise described herein.

[0074] If desired, addition of the alkali metal ions to the substantially alkali-free precipitate can be performed at any convenient time. For example, a small amount of an alkali metal ioncontaining liquid (e.g., an aqueous solution of alkali carbonate, alkali hydroxide, alkali acetate or alkali nitrate) can be added to the isolated (and optionally washed) precipitate; the person of ordinary skill in the art will appreciate that techniques like incipient wetness can be used. The precipitate can then be calcined to provide the Fischer-Tropsch catalyst material. In another embodiment, the isolated precipitate can first be calcined, then alkali added and the material calcined again to provide the alkali in oxidic form.

[0075] The person of ordinary skill in the art can use similar techniques to provide materials that include copper. It is noted that in many cases, copper can precipitate together with the zinc and iron. But impregnation can also be used to provide copper.

[0076] In other aspects, the present disclosure provides a Fischer-Tropsch catalyst as described herein made by a process as described herein.

[0077] Carbided Fischer-Tropsch Catalyst Material

[0078] Another aspect of the present disclosure provides a carbided Fischer-Tropsch catalyst material. The active species in iron-based Fischer Tropsch synthesis are generally understood to be carbide species. Thus, in some embodiments as described herein, the carbided Fischer-Tropsch catalyst material is a Fischer-Tropsch catalyst material as described herein, or a Fischer-Tropsch catalyst material made by a method as described herein, in a carbided form. In the carbided form, at least some of the iron included in the Fischer-Tropsch catalyst material is in the form of iron carbide.

[0079] Accordingly, another aspect of the disclosure is a carbided Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in the form of iron carbide.Such materials can be made, e.g., by the carbiding of the ZnFe204-containing Fischer-Tropsch catalyst materials described herein.

[0080] It can be desirable to have a substantial fraction of the iron of the carbided Fischer- Tropsch catalyst material in carbide form, as it is carbide forms that are of highest catalytic activity. For example, in various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, at least 60 atom% of the iron is in a carbide form, e.g., at least 70 atom%, or at least 80 atom%, or at least 90 atom%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 50-99 atom% of the iron is in a carbide form, e.g., in the range of 50-95%, or 50-90%, or 50-85%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 60-99 atom% of the iron is in a carbide form, e.g., in the range of 60-95%, or 60-90%, or 60-85%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 70-99 atom% of the iron is in a carbide form, e.g., in the range of 70-95%, or 70-90%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 80-99 atom% of the iron is in a carbide form, e.g., in the range of 80-95%, or 80- 90%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 90-99 atom% of the iron is in a carbide form, e.g., in the range of 90- 98%, or 90-95%. The amount of iron that is in the form of carbide is determined by Mbssbauer spectroscopy, and as such is expressed as an atomic fraction of iron in the form of carbide of the total iron species visible to Mbssbauer spectroscopy.

[0081] The present inventors note that oxidic iron forms are generally not active catalysts for Fischer-Tropsch synthesis. Accordingly, in various embodiments, it can be desirable to provide a carbided Fischer-Tropsch catalyst material with relatively low amounts of iron in oxidic form. For example, in various embodiments, the carbided Fischer-Tropsch catalyst materials described herein have no more than 20 atom% of iron in oxidic form, e.g., no more than 10 atom%, or no more than 5 atom%, or no more than 2 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. The person of ordinary skill in the art can, based on the disclosure herein, select reduction and carbiding conditions to provide a low degree of oxidic iron in the carbided Fischer- Tropsch catalyst materials of the disclosure.

[0082] For example, the present inventors note that oxidic carbon can catalyze water-gas shift reactions. In cases where the feed to the Fischer-Tropsch synthesis has relatively lowamounts of carbon dioxide, there is often no desire for water-gas shift activity, and so oxidic carbon can be minimized. Accordingly, in various embodiments in which the CO2 / CO ratio of the feed to a Fischer-Tropsch synthesis process is no more than 0.5 (e.g., no more than 0.2), no more than 20 atom% of iron of the carbided Fischer-Tropsch catalyst material is in oxidic form, e.g., no more than 10 atom%, or no more than 5 atom%, or no more than 2 atom%.

[0083] However, the present inventors have determined that it in some cases it can be desirable to retain some degree of oxidic iron in the carbided Fischer-Tropsch catalyst material. Accordingly, in in various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, at least 5 atom% of the iron is in an oxide phase, e.g., at least 10 atom%, or at least 15 atom%, or at least 20 atom%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 5-50 atom% of the iron is in an oxide phase, e.g., 5-45 atom%, or 5-40 atom%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 10-50 atom% of the iron is in an oxide phase, e.g., 10-45 atom%, or 10-40 atom%. In various embodiments of the carbided Fischer- Tropsch catalyst materials of the disclosure, in the range of 15-50 atom% of the iron is in an oxide phase, e.g., 15-45 atom%, or 15-40 atom%. In various embodiments of the carbided Fischer-Tropsch catalyst materials of the disclosure, in the range of 20-50 atom% of the iron is in an oxide phase, e.g., 20-45 atom%, or 20-40 atom%. In cases where the feed to the Fischer- Tropsch synthesis reaction has relatively high amounts of carbon dioxide, there is often a desire for water-gas shift activity, such that the reverse water-gas shift reaction can convert CO2to CO for use in the Fischer-Tropsch synthesis. Accordingly, in various embodiments in which the CO2 / CO ratio is in excess of 0.5, e.g., in excess of 1 , amounts of oxide phase as described here can be used.

[0084] Desirably, in the carbided Fischer-Tropsch catalyst materials of the disclosure the zinc remains largely in oxidic form. In various embodiments, at least 80 atom% of zinc present in the material is in oxidic form, e.g., at least 85 atom%, or at least 90%. The form of the zinc is measured by XRD, and as such is expressed as a fraction of zinc in oxidic form as compared to zinc in all forms detectable by XRD.

[0085] The amounts of iron and zinc, and, if present, alkali metal and / or copper, and ratios of iron to zinc in the carbided Fischer-Tropsch catalyst materials can be substantially as described above (i.e., but on an elemental basis exclusive of carbon for the carbided materials).

[0086] In some embodiments as described herein, the carbided Fischer-Tropsch catalyst material is an unsupported catalyst material. As such, in some embodiments as describedherein, at least 90 wt% of the carbided Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (if present), and copper (if present), as determined by ICP on an elemental basis exclusive of carbon. For example, in various embodiments as described herein, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, or at least 99.8 wt% of the carbided Fischer-Tropsch catalyst material is made up of iron and zinc, and, if present, alkali metal and / or copper, on an elemental basis exclusive of carbon.

[0087] In some other embodiments as described herein, the carbided Fischer-Tropsch catalyst material further comprises a support that supports the iron and zinc and, if present, alkali metal, and / or copper. As such, in some embodiments as described herein, at least 90 wt% of the carbided Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (i.e., if present), copper (if present), and the support, as determined by ICP, on an elemental basis exclusive of carbon. For example, in various embodiments as described herein, at least 95 wt%, at least 98 wt%, at least 99 wt%, at least 99.5 wt%, or at least 99.8 wt% of the carbided Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal (i.e., if present), copper (i.e., if present), and the support, on an elemental basis exclusive of carbon. The support itself can be provided as discrete bodies of material, e.g., as porous particles, pellets or shaped extrudates, with iron, zinc, and alkali metal and / or copper (if present), supported to provide the Fischer-Tropsch catalyst material. The support can also be provided as a binder that binds together particles containing iron and zinc. However, in other embodiments, the support can be provided as a monolithic material, e.g., an extrudate. In various embodiments, the support is formed from a refractory oxide. Of course, as would be understood by the person of ordinary skill in the art, other materials may be possible.

[0088] The person of ordinary skill in the art will appreciate that the carbided Fischer- Tropsch catalyst materials of the disclosure 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 reactor, a fluid bed reactor, a bubble column reactor, a so-called CANS reactor.

[0089] Notably, the present inventors have determined that especially desirable carbided Fischer-Tropsch catalyst materials have a high degree of x-Fe5C2. The present inventors have noted that such materials can be made by carbiding at relatively high temperatures, as described herein. The present inventors have determined that, surprisingly, carbided Fischer- Tropsch catalyst materials having high amounts of crystalline x-Fe5C2provide a significantly lower selectivity for oxygenated hydrocarbons and CO2than that typically provided by iron- catalyzed Fischer-Tropsch processes. However, the Fischer-Tropsch catalyst materialsdescribed herein can still provide similar performance (i.e. , CO2conversion and C5+ hydrocarbon selectivity) when carbided at a low temperature (e.g., 180 °C) but subjected to Fischer-Tropsch synthesis conditions at higher temperature. Without intending to be bound by theory, the present inventors believe that the increased temperature of the CO2Fischer-Tropsch conditions (e.g., when at least about 300 °C), transforms iron carbide formed during low temperature carbiding (i.e., E-Fe3C and q-Fe2C) into x-Fe5C2.

[0090] Accordingly, in various embodiments as described herein, the carbided Fischer- Tropsch catalyst material comprises x-Fe5C2. In various embodiments, at least 50 atom% of the carbided iron of the carbided Fischer-Tropsch catalyst material is in the form of x-Fe5C2, e.g., at least 60 wt%, or at least 70 wt%. In various embodiments, at least 75 atom% of the carbided iron of the carbided Fischer-Tropsch catalyst material is in the form of x-Fe5C2, e.g., at least 80 wt%. In various embodiments, at least 85 atom% of the carbided iron of the carbided Fischer- Tropsch catalyst material is in the form of x-Fe5C2, e.g., at least 90 wt%. The state of the iron in the carbided catalyst is determined by Mbssbauer spectroscopy as described above.

[0091] Processes for Carbiding

[0092] The carbided Fischer-Tropsch catalyst materials of the disclosure can be prepared by carbiding various Fischer-Tropsch catalyst materials described herein.

[0093] Accordingly, another aspect of the disclosure is a process for carbided Fischer- Tropsch catalyst material as described herein. The process comprises carbiding the Fischer- Tropsch catalyst material to provide the carbided Fischer-Tropsch catalyst material.

[0094] The carbiding can be performed in any convenient manner. Conventionally, iron- containing Fischer-Tropsch catalyst materials are prepared for use as active Fischer-Tropsch catalysts by treating them in situ with a reducing gas such as hydrogen, under conditions sufficient to convert a substantial amount of the iron oxides of the calcined Fischer-Tropsch catalyst material to metallic iron. Then, when exposed to Fischer-Tropsch reaction conditions, a substantial part of this iron is converted to carbide by carbon monoxide of the Fischer-Tropsch feed. It is thus not conventionally necessary to provide a separate carbiding treatment; rather, the carbiding is a natural result of Fischer-Tropsch reaction conditions. However, such Fischer- Tropsch processes tend to exhibit longer induction periods and a relatively higher degree of water-gas shift activity, especially at moderate Fischer-Tropsch reaction temperatures. This can result in a relatively lower conversion of carbon monoxide to desirable C5+ products. Without intending to be bound by theory, the present inventors believe that this could result fromincomplete carbide formation, such that there is still partially reduced or in an oxidic form. Nonetheless, the materials of the disclosure can be especially useful in such methods, since the absence of low concentrations of alkali metal and / or copper can provide for relatively lower water-gas shift activity than can materials having higher concentrations of alkali metal and / or copper.

[0095] The Fischer-Tropsch catalyst materials of the disclosure can be advantageous in such in situ carbiding methods, i.e., when carbiding is performed via exposure Fischer-Tropsch reaction conditions, when the Fischer-Tropsch reaction is performed at temperatures of at least 300 °C, e.g., at least 325 °C. or at least 350 °C. At such temperatures, the in situ carbiding can provide a high degree of carbide in the form of x-Fe5C2, e.g., to provide a carbided Fisher- Tropsch catalyst material of the disclosure for use in the Fischer-Tropsch synthesis.

[0096] However, the present inventors note that catalysts with a high degree of carbide in the form of x-Fe5C2can be especially desirable for use in FT processes conducted at temperatures below 300 °C in order to provide higher C5+ selectivity, and so it can be especially desirable to carbide at high temperature in a separate operation as otherwise described herein.

[0097] Another aspect of the disclosure is a process for making a carbided Fischer-T ropsch catalyst material as described herein. The process comprises carbiding the Fischer-Tropsch catalyst material to provide the carbided Fischer-Tropsch catalyst material.

[0098] The carbiding can be performed in any convenient manner. For example, in various embodiments, the carbiding includes a reduction step, in which the Fischer-Tropsch catalyst material is treated with a reducing gas stream (e.g., containing hydrogen) for a time and at a temperature sufficient to provide at least 50 atom% of the catalyst in metallic form. Without intending to be bound by theory, the inventors understand this step to reduce oxidic iron species to metallic iron species, so that they can be more easily carbided in a subsequent treatment with a carbiding gas. Upon treatment with the reducing gas stream, a portion of the iron components present in the Fischer-Tropsch catalyst material as described herein react to metallic iron (Fe°). However, it was found that ZnO present in the Fischer-Tropsch catalyst material is not substantially reduced during the reducing treatment.

[0099] In various embodiments, the treatment with the reducing gas stream is performed in the substantial absence of carbon monoxide. For example, in various embodiments, the reducing gas stream comprises no more than 1 vol% carbon monoxide, e.g., no more than 0.5 vol%, or no more than 0.1 vol%, or no more than 0.05 vol%, or no more than 0.01 vol% carbonmonoxide. In some embodiments as described herein, the reducing gas stream further comprises an inert gas. For example, in some embodiments, the inert gas is nitrogen. In some embodiments as described herein, the hydrogen and inert gas are present in the reducing gas stream in a ratio of at least 1 :1.

[0100] In various embodiments, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted at a temperature in the range of 250-650 °C. For example, in various embodiments as described herein, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted at a temperature in the range of 250-600 °C, or 250-550 °C, or 250-500 °C . In various embodiments as described herein, treating the Fischer-Tropsch catalyst material with the Fischer-Tropsch reducing gas stream is conducted at a temperature in the range of 300-650 °C, or 300-600 °C, or 300-550 °C, or 300-500 °C. In various embodiments as described herein, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted at a temperature in the range of 350-650 °C, or 350-600 °C, or 350-550 °C, or 350-500 °C.

[0101] As described above, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted for a time sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in metallic form. In various embodiments, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted for at least 12 hours, e.g., at least 14 hours. For example, in various embodiments as described herein, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted for a time in the range of 12 to 30 hours, e.g., in the range of 12 to 24 hours, or 14 to 30 hours, or 14 to 24 hours.

[0102] The person of ordinary skill in the art will be able to determine appropriate reducing conditions to provide a Fischer-Tropsch catalyst material with at least 50 atom% iron in reduced form. While the paragraphs above provide guidance for reducing gas streams, temperatures and times, the person of ordinary skill in the art will be able to, based on the present disclosure, provide suitable reduction conditions to provide a substantially reduced Fischer-Tropsch catalyst material. In various embodiments, the treatment with the reducing gas stream is performed to provide a Fischer-Tropsch catalyst material in which at least 60 atom% of the iron is in reduced form, e.g., at least 70 atom%. In various embodiments, the treatment with the reducing gas stream is performed to provide a Fischer-Tropsch catalyst material in which at least 80 atom% of the iron is in reduced form, e.g., at least 85 atom%. The proportion of iron in reduced form is measured by XRD.

[0103] Moreover, the present inventors note that in some cases a pre-reduction step may not be necessary, as there will often be hydrogen present during the carbiding, and that hydrogen can reduce iron to metallic iron which can be subsequently converted to carbide. Accordingly, in some embodiments, the Fischer-Tropsch catalyst material is in oxidic form when treated with the carbiding gas stream; in such embodiments, the treatment with the carbiding gas stream is desirably performed in the presence of hydrogen.

[0104] The carbiding can include treating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide (e.g., carbon monoxide), at a temperature of at least 180 °C for a time sufficient to provide at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material in carbided form. This can be performed, e.g., after a treatment with a reducing gas as described above , or, in cases where hydrogen is present in the carbiding gas stream, on a Fischer-Tropsch catalyst material in substantially oxidic form.

[0105] The present inventors have determined in particular that catalyst carbiding can be performed in such a manner so as to reduce the water-gas shift activity of the catalyst and thereby reduce CO2selectivity and increase C5+ selectivity. Thus, not only can the properties of the as-calcined catalyst material (e.g., relative amounts of metallic constituents and amount of ZnFe2O4crystalline phase) and the Fischer-Tropsch reaction parameters (e.g., temperature, GHSV, H2 / CO ratio) affect selectivity of the active Fischer-Tropsch catalyst material, so too can the conditions under which the Fischer-Tropsch catalyst material is activated by carbiding. The present inventors have determined that, the carbiding conditions themselves can be varied to provide particular desirable activity in the Fischer-Tropsch synthesis. Thus, while the compositions of the disclosure can be useful even when carbided under different conditions, in various embodiments, the Fischer-Tropsch catalyst materials of the disclosure are carbided as described herein.

[0106] In various embodiments, the Fischer-Tropsch catalyst material is treated with a carbon monoxide and / or carbon dioxide-containing gas (e.g., carbon monoxide-containing gas) to provide carbided Fischer-Tropsch catalyst material. In various embodiments, the carbiding gas stream comprises carbon monoxide. However, the present inventors note that in some cases carbon dioxide may be suitable for providing carbon for carbiding; without intending to be bound by theory the present inventors surmise that the high water-gas shift activity of iron (e.g., in oxide form) can cause carbon dioxide, in the presence of hydrogen, to be converted via the reverse water-gas shift reaction to carbon monoxide, which can be the active carbiding species.

[0107] Without intending to be bound by theory, the inventors surmise that reduced iron is converted to carbide, while oxidic zinc remains largely in oxide form. Oxidic iron, depending on carbiding reaction conditions, may remain as oxidic iron or may be reduced to metal by hydrogen in the carbiding gas stream then carbided; typically a combination of these will occur. Without being bound by theory, the present inventors hypothesize that the ZnO is positioned between carbide sites, holding them in place and preventing sintering that would decrease activity over time. Additionally, the basic character of Zn acts as promoter for higher chain growth probability when in the vicinity of iron carbide sites; the fine dispersion of the ZnO islands resulting from the use of zinc ferrite is especially beneficial in this regard.

[0108] The present inventors have found that carbiding conditions can significantly affect the activity of the carbided Fischer-Tropsch catalyst material in use. The present inventors have determined that, despite the fact that carbon monoxide and / or carbon dioxide (e.g., carbon monoxide) is the species providing the carbon for the carbiding, it can be advantageous to use a significant amount of hydrogen in the carbiding gas stream. Thus, in various embodiments, the carbiding gas stream includes hydrogen in addition to carbon monoxide and / or carbon dioxide. For example, in some embodiments as described herein, the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of at least 1 :1 hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide). For example, in various embodiments, the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide) of at least 2:1 , or at least 5:1 , or at least 10:1 , or at least 15:1 , or at least 20:1 , or at least 25:1 , or at least 30:1 . In some embodiments as described herein, the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide) of 1 :1 to 100:1 , e.g., in the range of 2:1 to 100:1 , or 5:1 to 100:1 , or 10:1 to 100:1 , or 15:1 to 100:1 , or 20:1 to 100:1 , or 25:1 to 100:1 , or 30:1 to 100:1. In some embodiments as described herein, the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide) of 1 :1 to 50:1 , e.g., in the range of 2:1 to 50:1 , or 5:1 to 50:1 , or 10:1 to 50:1 , or 15:1 to 50:1 , or 20:1 to 50:1 , or 25:1 to 50:1 , or 30:1 to 50:1. In various embodiments in which hydrogen is provided together with the carbon monoxide and / or carbon dioxide in the carbiding gas, it may not be necessary to perform a separate reduction step beforehand; hydrogen in the carbiding gas can reduce the oxidic iron to metallic iron, which can then be carbided by the carbon monoxide / carbon dioxide present.

[0109] As described above, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature of at least 180 °C. For example, in various embodiments, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature of at least 200 C, e.g., at least 220 °C. For example, in various embodiments, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 180-450 °C (e.g., in the range of 180-400 °C, or 180-350 °C, or 180-300 °C). In various embodiments, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 200-450 °C (e.g., in the range of 200-400 °C, or 200-350 °C, or 200-300 °C). In various embodiments, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 220-450 °C (e.g., in the range of 220-400 °C, or 220-350 °C, or 220- 300 °C). Without intending to be bound by theory, it is believed that carbiding at lower temperatures provides carbided Fischer-Tropsch materials having a high proportion of carbide in the E-Fe3C and q-Fe2C forms. Such materials are believed to be useful catalyst materials, albeit with lower selectivity to olefins and higher selectivity to oxygenated hydrocarbons and carbon dioxide.

[0110] The present inventors have found that carbiding temperature has a significant effect on the activity of the carbided Fischer-Tropsch catalyst under FT reaction conditions. For example, the present inventors have found that carbiding at relatively high temperatures can provide a carbided Fischer-Tropsch catalyst material with high selectivity for C5+ hydrocarbons, with an increased proportion of olefins. The present inventors have noted, unexpectedly, that high temperature carbiding can provide catalysts with high amounts of x-Fe5C2. The person of ordinary skill in the art can determine, based on the present disclosure, carbiding conditions suitable to provide a carbided Fischer-Tropsch catalyst material having a high degree of x- Fe5C2, for example, in proportions as described above.

[0111] Accordingly, in various embodiments, treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of at least 300 °C, e.g., at least 325 °C, or at least 350 °C, or at least 375 °C, or at least 400 °C. For example, in various embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 300-650 °C, e.g., 300-600 °C, or 300-550 °C or 300-500 °C. For example, in various embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 325-650 °C, e.g., 325-600 °C, or 325-550 °C, or 325-500 °C. Invarious embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 350-650 °C, e.g., 350-600 °C, or 350-550 °C, or 350-500 °C. In various embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 375-650 °C, e.g., 375-600 °C, or 375-550 °C, or 375-500 °C. In some embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature in the range of 400-650 °C, e.g., 400-600 °C, or 400-550 °C, or 400-500 °C.

[0112] Moreover, even when a Fischer-Tropsch catalyst material is initially carbided under lower temperature conditions to form E-Fe3C and q-Fe2C, it can, under some high-temperature Fischer-Tropsch reaction conditions, convert to x-Fe5C2. This may require a significant induction period under Fischer-Tropsch reaction conditions. Moreover, in such high- temperature Fischer-Tropsch processes C5+ selectivity can suffer due to the formation of relatively more C1-C4 hydrocarbons; accordingly, it may often be desirable to perform a separate high-temperature carbiding and operate the Fischer-Tropsch synthesis itself at lower temperatures (e.g., below 300 °C).

[0113] As described above, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted for a time sufficient to provide at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material in carbided form. For example, in various embodiments, the treating of the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted for a time of at least 3 hours, e.g., at least 5 hours. In various embodiments, the treating of the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted for a time in the range of 3-20 hours, e.g., 5-20 hours, or 3-15 hours, or 5-15 hours.

[0114] Fischer-Tropsch Processes

[0115] Another aspect of the present disclosure provides a process for performing a Fischer-Tropsch synthesis reaction. The process includes providing a carbided Fischer- Tropsch catalyst material as described herein, and contacting at a reaction temperature and pressure the Fischer-Tropsch catalyst with a feed stream comprising H2and CO to provide a product stream comprising C5+ hydrocarbons. An example of such a process is shown schematically in FIG. 1. In FIG. 1 , the process 100 includes contacting at a temperature and at a pressure a carbided Fischer-Tropsch catalyst material as described herein with a feed stream comprising H2and CO to provide a product stream comprising C5+ hydrocarbons. In the process 100 of FIG. 1 , the feed stream 121 , which is contacted with Fischer-Tropsch catalystmaterial 123, here, in a reaction zone (e.g., a reactor 120). This provides a product stream 122, which includes C5+ hydrocarbons. Notably, the carbided Fischer-Tropsch catalyst material can be provided by a separate carbiding operation, or rather can be carbided in situ under the Fischer-Tropsch reaction conditions.

[0116] H2and CO can be provided to the feed stream from a variety of sources. The person of ordinary skill in the art will appreciate that H2can be provided from a variety of sources, e.g., gasification, reforming, or H2O electrolysis. Moreover, as described in more detail below, H2can be recycled to the feed stream from the product stream. Carbon monoxide from a variety of sources, such as fossil-based sources (e.g., natural gas), may be utilized in admixture with the streams as described herein. In various embodiments as otherwise described herein, the process further comprises providing carbon monoxide from a fossil source in the H2 / CO stream. In some embodiments, the person of ordinary skill in the art can provide CO by reacting CO2in a reverse water-gas shift reaction; excess hydrogen can be input to such a process, so that the output of the reverse water-gas shift reaction can include both CO and H2to be provided to the feed stream.

[0117] As described above, CO and H2are 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.

[0118] For example, H2can be provided from environmentally-responsible sources. In some embodiments, at least a part of the H2of the 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 H2of the 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 H2of the 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 H2can 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 H2of the feed stream is grey hydrogen, black hydrogen, brown hydrogen, pink hydrogen, turquoise hydrogen, yellow hydrogen, and / or white hydrogen.

[0119] The present inventors have noted that electrolysis of water can be a desirable way to provide hydrogen to the claimed processes. Accordingly, in some embodiments, the process includes providing at least a portion of H2to the feed stream by electrolysis of water. In some embodiments, the electrolysis of water is performed using at least partially electricity from arenewable 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 first or second 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. In some embodiments, at least a portion of O2generated in the electrolysis is provided to a partial oxidation reaction zone as described herein.

[0120] As described above, the feed stream contains both H2and CO and the feed stream includes all feeds to the Fischer Tropsch reactor, regardless of whether the feed stream is provided as a mixture of feeds or as feeds provided individually to a reaction zone. In various embodiments of the present disclosure as described herein, the feed stream has a H2:CO ratio in the range of 0.5:1 to 6:1 . In some embodiments, the 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 feed stream has a H2:CO ratio of at least 1 .4:1 . For example, in some embodiments, the feed stream has a H2:CO ratio in the range of 1.4:1 to 3:1 , or 1.4:1 to 2:1. In some embodiments, the feed stream has a H2:CO ratio of at least 2:1 . For example, in some embodiments, the feed stream has a H2:CO ratio in the range of 2:1 to 6:1 , or 2:1 to 4:1. The person of ordinary skill in the art will provide a desired ratio of H2:CO in the feed stream, based on the disclosure herein that provides a desirable conversion and selectivity in the Fischer-Tropsch process.

[0121] Other gases may also be included in the feed stream. For example, it can be desirable to perform the Fischer-Tropsch process step in the presence of a significant amount of inerts (i.e. , components that are not H2or CO). For example, in various embodiments, the 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 feed stream includes up to 70 mol% inerts, up to 60 mol% inerts, 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 feed stream includes up to 80% of one or more inerts selected from methane and nitrogen, 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%.

[0122] To reduce WGS activity, it can be desirable to have CO2present in the feed stream; as the water-gas shift is generally an equilibrium process, the presence of CO2helps to disfavorthe conversion of CO to CO2. In various embodiments, the 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%. In various embodiments, the molar ratio of CO2to CO in the feed stream is at least 0.5:1 , e.g., at least 0.7:1 or at least 1 :1. However, catalysts of the disclosure can also be used in cases where the molar ratio of CO2to CO in the feed stream is no more than 0.5, e.g., no more than 0.3. In various embodiments, the molar ratio of CO2to CO in the feed stream is no more than 0.15, e.g., no more than 0.1 , or no more than 0.05.

[0123] Similarly, to reduce water-gas shift activity, it can be desirable to reduce the amount of water that is conducted to the Fischer-Tropsch process step. Accordingly, in various embodiments as otherwise described herein, the 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%. Maintaining a low amount of water can have additional benefits, such as improving catalyst stability.

[0124] The Fischer-Tropsch catalyst materials as described herein are suitable for use in the Fischer-Tropsch processes described herein. The person of ordinary skill in the art will appreciate that the Fischer-Tropsch catalyst materials of the disclosure 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 fluidized bed. The person of ordinary skill in the art will select an appropriate form of the Fischer-Tropsch catalyst material for the particular reactor system.

[0125] For example, in various embodiments, the Fischer-Tropsch catalyst material is first reduced by contact with a reducing gas. For example, hydrogen can be an especially suitable gas for activating the Fischer-Tropsch catalyst material, e.g., when the activation includes a reduction to metal(O) species. In various embodiments of the present disclosure as otherwise described herein, the feed stream and the reaction conditions in the Fischer-Tropsch reaction system can be adjusted to provide desired reduction conditions. In the process 200 shown schematically in FIG. 2, the feed stream 221 is adjusted appropriately and contacted with the Fischer-Tropsch catalyst 223 under appropriate reduction reaction conditions in reaction zone 220 to reduce it. The reduction can be performed, e.g., as described above.

[0126] In various embodiments, and as described above, the reduced Fischer-Tropsch catalyst material can be carbided by contact with CO. Here, too, the feed stream can be adjusted to provide a desired amount of CO, and reaction conditions in the reactor can be suitably modified to provide for carbidization of the Fischer-Tropsch catalyst material, as described above. In the process 200 shown schematically in FIG. 2, the feed stream 221 isadjusted appropriately and contacted with the Fischer-Tropsch catalyst material 223 in reaction zone 220 to carbide it. Carbidization can be performed, e.g., as described above.

[0127] However, separate carbiding processes are not necessary, as the Fischer-Tropsch catalyst material can be carbided under the Fischer-Tropsch reaction conditions, especially when treated first with a reducing gas as described above.

[0128] As described above, the process includes contacting at a temperature and at a pressure the Fischer-Tropsch catalyst with a feed stream. 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 Fischer-Tropsch processes. In some embodiments of the disclosure as described herein, the temperature is in the range of 150-400 °C. For example, in various embodiments, the temperature is in the range of 150-350 °C, or 150-300 °C, or 150-290 °C, or 150-280 °C, or 150-265 °C, or 150-250 °C, or 150-200 °C. In various embodiments, the temperature is in the range of 180-400 °C, e.g., in the range of 180-350 °C, or 180-300 °C, or 180-280 °C, or 180-265 °C, or 180-250 °C, or 180-225 °C, or 180-200 °C. In various embodiments, the temperature is in the range of 200-400 °C, e.g., in the range of 200-350 °C, or 200-300 °C, or 200-280 °C, or 200-265 °C, or 200-250 °C, or 200-225 °C. In various embodiments, the temperature is in the range of 220-400 °C, e.g., in the range of 220-350 °C, or 220-300 °C, or 220-280 °C, or 220-265 °C, or 220-250 °C. In various embodiments, the temperature is in the range of 250-400 °C, e.g., in the range of 250-350 °C, or 250-300 °C, or 250-280 °C. In various embodiments, the temperature is in the range of 300-400 °C. In some particular embodiments, the temperature is in the range of 200-350 °C. In some particular embodiments, the temperature is in the range of 200-280 °C, or 200-250 °C.

[0129] In some embodiments of the disclosure as described herein, the pressure is in the range of 10-50 barg. For example, in various embodiments, the 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. In some embodiments, the pressure is in the range of 20-50 barg.

[0130] The Fischer-Tropsch processes 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 Fischer-Tropsch reaction is not particularly limited. For example, in some embodiments of the present disclosure, the process for performing the Fischer-Tropsch reaction is conducted at a GHSV in the range of 1 ,000 to 2,000,000 h’1. In various embodiments, the process for performing the reverse water-gas shift reaction is conducted at a GHSV in the range of 1 ,000 to 1 ,200,000 h’1, or 1 ,000 to 500,000 hr1,or 1 ,000 to 100,000 h’1, or 5,000 to 1 ,200,000 h’1, or 5,000 to 500,000 h’1, or 5,000 to 100,000 IT1, or 10,000 to 1 ,200,000 h’1, or 10,000 to 500,000 h’1, or 10,000 to 100,000 IT1. In various embodiments of the present disclose, the process for performing the Fischer-Tropsch reaction is conducted at a GHSV in the range of 1 ,000 to 50,000 h’1, or 2,000 to 50,000 h’1, or 5,000 to 50,000 IT1, or 10,000 to 50,000, or 1 ,000 to 40,000 h’1, or 2,000 to 40,000 h’1, or 5,000 to 40,000 IT1, or 10,000 to 40,000 h’1, or 1 ,000 to 30,000 h’1, or 2,000 to 30,000 h’1, or 5,000 to 30,000 h’1, or 10, 000 to 30,000 IT1.

[0131] The Fischer-Tropsch 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). In various embodiments of the disclosure as described herein, contacting the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C5+ selectivity (i.e. , for all C5+ species) of at least 30%, e.g., at least 40%, or at least 50%. For example, in some embodiments, the selectivity for C5+ alkanes is at least 30%, e.g., at least 40%, or at least 50%. In some embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C5+ selectivity of at least 60%, e.g., at least 70%, or at least 80%. In some embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-4 selectivity of no more than 30%, e.g., no more than 25%, or no more than 20%. In some embodiments, the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a methane selectivity of no more than 20%, e.g., no more than 15%, or no more than 10%, or no more than 5%. In some embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2.8oxygenate selectivity of no more than 30%, e.g., no more than 25%, or no more than 20%. In some embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8oxygenate selectivity of no more than 15%, e.g., no more than 10%, or no more than 5%.

[0132] Additional components may be in present in the product stream. For example, in some embodiments, the product stream includes water, which is another product of the Fischer- Tropsch reaction. Also present can be one or more light hydrocarbons (i.e., C1-C4) as a side product. CO and / or H2can be present, e.g., unreacted from the feed stream. CO2or other inerts as described herein can also be present. Such components of the product stream can be separated and / or recycled in various manners.

[0133] For example, in various embodiments, the process further comprises separating at least a portion of water from the product stream. This is shown schematically in FIG. 3. In the embodiment of FIG. 3, reaction zone 320 is a volume of the reactor 305 that includes the bed 324 containing the carbided Fischer-Tropsch catalyst material 323. The feed stream 321 is passed to the carbided Fischer-Tropsch catalyst material 323 to provide second 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 product stream 322 to provide watercontaining stream 334.

[0134] Light hydrocarbons, while often not a desired portion of a Fischer-Tropsch product to be used as a fuel or a lubricant, can themselves be useful for a number of purposes.Accordingly, in various embodiments, the process further includes separating at least a portion of C1-C4 hydrocarbons from the second product stream to provide a light hydrocarbon stream. The light hydrocarbon stream can, for example, be recycled to the first feed stream or the second feed stream. For example, in the process 200 of FIG. 2, light hydrocarbons from product stream 222 can be provided as part of the recycle stream 236, which becomes part of the 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 feed stream 321 . In the process 400 of FIG. 4, light hydrocarbons are recycled via recycle stream 442 to first feed stream 421 .

[0135] 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 C02-containing partial oxidation (pOX) stream, and including at least a portion of the pOX stream in feed stream. An example of such a process is shown schematically in FIG. 4, in which the process 400, the feed stream 421 , the product stream 422, the reaction zone 420, and the Fischer-Tropsch 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 CO2containing pOX stream, and including at least a portion of the pOX stream 454 stream in the feed stream 421 .

[0136] 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 heatenergy may be used to provide the needed heat duty for the Fischer-Tropsch 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 feed stream 421 .

[0137] Heat can be exchanged from the 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 product stream and at least a portion of the feed stream, thereby cooling at least a portion of the product stream and heating at least a portion of the feed stream. In process 300 of FIG. 3, heat is exchanged between at least a portion of the product stream 322 and feed stream 321 in a second heat exchange zone 330, thereby cooling the product stream 322 and heating the feed stream 321 . The person of ordinary skill in the art will appreciate that a wide variety of heat exchangers can be used for this purpose.

[0138] Of course, any excess heat in the 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 product stream and a steam generation zone, thereby cooling at least a portion of the product stream and providing heat to the steam generation zone. This is shown in FIG. 3. Here, after heat exchange with the feed stream 321 , the product stream 322 is conducted to steam generation zone 332, to cool the 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).

[0139] It can be desirable to recycle hydrogen from the product stream, for example, to the feed stream. For example, in various embodiments, the process includes recycling at least a portion of H2of the product stream to the feed stream. For example, in the process of FIG. 2, at least a portion of H2of the product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the feed stream 221 via recycle stream 236.

[0140] Similarly, it can be desirable to recycle CO of the product stream, for example, to the feed stream. For example, in various embodiments, the process includes recycling at least a portion of CO of the product stream to the second feed stream. For example, in the process of FIG. 2, at least a portion of CO of the product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the feed stream 221 via recycle stream 236.

[0141] In many cases, both CO and H2of the second product stream will be recycled.

[0142] Moreover, when one or more inerts are used in the Fischer-Tropsch process step, it can be desirable to recycle these. For example, in various embodiments, the process includes recycling at least a portion of inerts of the product stream to the feed stream. For example, in the process of FIG. 2, at least a portion of inerts of the product stream (e.g., at least 25%, at least 50%, or at least 75%) can be recycled to the feed stream 221 via recycle stream 236. In various embodiments, the process includes recycling at least a portion of inerts of the product stream to the 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] As noted above, the Fischer-Tropsch process step provides a 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 second 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.

[0144] 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 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 here. For example, in the process 300 of FIG. 3, second product stream 322 is hydroprocessed in hydroprocessing reactor 350, to provide a hydroprocessed product stream 352.

[0145] The person of ordinary skill in the art will provide the materials and perform the processes described herein based on the general disclosure above, and with reference to the Examples below.EXAMPLES

[0146] The Examples that follow are illustrative of specific embodiments of the materials and process of the disclosure, and various uses thereof. They are set forth for explanatory purposes only, and are not to be taken as limiting the scope of the disclosure.

[0147] Example 1 . Process for Preparing Low-Alkali metal Fe-Zn Catalyst Material

[0148] A low-alkali metal Fe-Zn catalyst material as described herein was prepared by precipitating iron and zinc carbonates from a solution of iron nitrate and zinc nitrate under basic conditions. The amounts of iron and zinc compounds used provided a catalyst material with a Fe:Zn molar ratio of 1 :1 . Specifically, 242.40 g of Fe(NO3)39H2O and 178.49 g of Zn(NO3)2-6H2O were dissolved in 500 g of deionized water to obtain a clear solution. Additionally, 158.99 g of Na2CO3was dissolved in 500 g of deionized water to obtain a solution of precipitating ions. To form the Fischer-Tropsch catalyst material, 1200 g of deionized water was weighed into a 5-neck round bottom flask equipped with a mechanical stirrer, a heating mantle / temperature control system, and a condenser. The temperature of the water in the round bottom flask was increased to 80 °C, then pH was adjusted to approximately 9 with the Na2CO3solution. The iron / zinc solution and the Na2CO3solution were then added simultaneously at roughly the same rate while monitoring the pH value of the slurry; the pH of the slurry was maintained at approximately 9 by controlling the rate of addition of the Na2CO3solution. Upon combination, a precipitate formed, which was aged at 80 °C for 2h. After aging, the slurry was divided equally among six 1000 mL centrifuge bottles. Using a centrifuge (at 9000 rpm for 10 min), the solids were separated out of the slurry and collected. The solids were re-slurried in 4L of deionized water under vigorous stirring for approximately 15 min, then separated again with the centrifuge. This separation and re-slurrying process was repeated 4 more times. The solids were collected using a vacuum filtration system. The solids were then dried in a hood overnight and then further dried in an oven at 110 °C overnight. Lastly, the sample was calcined at 300 °C for 4 h via a heating ramp of 2 °C / min to obtain the final catalyst material.

[0149] Example 2. Process for Reducing Alkali Metal Load in Fe-Zn Catalyst Material with Additional Washing

[0150] This example explores the use of washing (i.e., via re-slurrying as described above) to further reduce the level of sodium in these catalysts. In brief, the reaction was carried out as follows and in accordance with the procedure described in Example 1 :

[0151] The metal salts (Fe(NO3)3-9H2O, 40.4g; Zn(NO3)26H2O, 29.7g) were dissolved in 83 mL of deionized water to provide an iron / zinc solution. Na2CO3was dissolved in 83 mL of deionized water and placed in a pressure equalized dropping funnel attached to a 3-necked 500 mL round bottomed flask. 200 mL of deionized water was added to the 500 mL flask along witha magnetic stirbar. The water was heated to 80 °C and the was adjusted to a pH of 9 using the Na2CO3solution. The Fe / Zn solution was added to the reaction flask by means of a peristaltic pump set at 5 mL / min with the pH being maintained at 9 using manual control of the sodium carbonate addition using the pressure equalized dropping funnel. The sodium carbonate solution was consumed before all the metal salt solution had been added. The container containing the metal salt solution was rinsed with deionized water and the solution was aged at 80 °C for 2 hours, then filtered and washed with multiple aliquots of deionized water. Samples of washed solid were collected at different stages of washing (Table 1). Each sample was dried in a fume cupboard overnight followed by drying in a muffle furnace in air using the following conditions: 2 °C / min to 110 °C for 12 hours.

[0152] Table t .

[0153] Sample 5 was then split into four portions to determine appropriate calcination conditions. Each portion was calcined at a different temperature (300 °C, 350 °C, 400 °C, and 450 °C). Each sample was studied by x-ray diffraction (XRD) to identify the phases present, and it was observed that all samples comprise ZnFe2O4and ZnO with no carbonates and no other iron oxide species observable by XRD. As there was no evidence of carbonate in these experiments, it was decided that the materials were to be calcined at 350 °C (2 °C / min ramp) and held at that temperature for 4 hours.

[0154] With appropriate calcination conditions determined, samples 1-5 described in Table 1 were calcined and then subjected to ICP analysis. The results of the ICP analysis are shown in Table 2. Amounts of iron, zinc and sodium are reported as a fraction of the total mass of the material, i.e., including oxygen.

[0155] Table 2.

[0156] Example 3. Alkali Metal-Free Preparation of Fe-Zn Catalyst Materials

[0157] The precipitating agent used in Example 1 , sodium carbonate, was replaced with ammonium hydroxide (34% in water). In brief, the reaction was carried out as follows:

[0158] The metal salts (Fe(NO3) 9H2O, 40.4g; Zn(NO3)26H2O, 29.7g) were dissolved in 300 mL of deionized water and placed in a 1 liter 3 necked flask with a magnetic stirrer bar.Ammonium hydroxide (34%) was placed in a pressure equalized dropping funnel. The reaction flask containing the metal nitrate solution was heated to 80 °C with stirring and once at temperature the ammonium hydroxide was added dropwise until the pH of the solution reached 8.3. After the solution reached a pH of 8.3 the solution is aged for 1 hour at 80 °C then cooled to room temperature. Upon cooling the mixture was filtered on a Buchi filtration apparatus and then washed with 7 aliquots of deionized water (250 mL). The material was dried overnight in a fume hood, followed by drying in an oven at 110 °C for 12 hours. This provided sample no. 6.

[0159] Sodium was added to sample no. 6 using incipient wetness impregnation using a sodium nitrate solution at varying concentration to provide a desired sodium loading. The level of water for an incipient wetness impregnation of the base materials was 1 mL. After impregnation the materials were dried at room temperature followed by oven drying at 110 °C for 12 hours and calcination at 350 °C for 4 hours. Table 3 described the ICP results of these samples with sodium addition by incipient wetness impregnation. Amounts of sodium are reported as a fraction of the total mass of the material, i.e., including oxygen.

[0160] Table 3.

[0161] Example 4. Influence of Zinc / lron Ratio

[0162] To investigate the influence that the ratio of zinc to iron has on the Fischer-Tropsch catalyst materials, two materials were prepared with different molar ratios, shown below in Table 4. For each system two levels of sodium were produced by the controlled washing method described in Example 2. Amounts of sodium are reported as a fraction of the total mass of the material, i.e., including oxygen.

[0163] Table 4.

[0164] The materials were made using the same procedure as before with altered quantities of metal salt precursors, as described in Table 4. Sodium carbonate was used as the precipitating agent and the level of sodium in the materials was controlled by washing and measuring conductivity. Accordingly, sample no. 11 and sample no. 14 were taken when conductivity measurements were ~1500 pS and sample no. 12 and sample no. 15 were taken when conductivity was ~ 25 pS. All materials were allowed to dry overnight in the fume cupboard followed by drying / calcination in the muffle furnace using the following program: 2°C / min 110°C 12 hours and 2°C / min 350°C for 4 hours.

[0165] Example 5. Performance of Alkali Metal-Free Fe-Zn Catalysts

[0166] Fe-Zn catalyst materials as described herein were then tested for their C5+ selectivity in a Fischer-Tropsch process. Catalyst testing was performed using a 4-fold parallel fixed bed reactor unit, each reactor tube having an internal diameter of 6.5 mm and independent temperature and gas feed flow control. Catalysts were diluted with SiC for better temperature distribution along the bed, avoiding the formation of hot spots. The unit has two product knockout pots: a first hot pot at 180 °C to collect high boiling waxes; and a cold pot at 12 °C to collect water and light organics. Gas chromatography (GC) was used to analyze the feed composition inlet and product stream after the knockout pots for each of the 4 reactor tubes. The GC has channels for detecting hydrogen and other gases (i.e., CH4, CO2, Ar, N2, and CO) using a thermal conductivity detector (TCD), as well as a channel for detecting light organics (i.e., C1-C5 hydrocarbons) using a flame ionization detector (FID).

[0167] Table 5 describes the conditions of the Fischer-Tropsch process used, and the performance of the catalyst under different conditions. The catalyst had an Fe / Zn molar ratio of 1.1 :1 and were substantially free of alkali and copper. The “Syngas GHSV” is the hourly space velocity of only the syngas components CO and H2; 15-30% inert was also present in the feed gas stream.

[0168] Table 5.

[0169] The Syngas GHSV defined in Table 5 takes only the H2and CO in the gas composition to account; inert gas components (i.e., CH4, N2, Ar, etc.) are ignored. High C5+ productivities and low CO2selectivities are achieved at CO conversion levels greater than 20%, as shown in Table 5. This is achieved by omitting or limiting the presence of alkali metal promoters (such as K or Na) to low levels, in combination with the high temperature carbiding pre-treatment as described in Example 7.

[0170] Example 6. Performance of Low-Alkali Metal Fe-Zn Catalyst Materials

[0171] Further improvements are observed when low amount of alkali metal is present in the Fischer-Tropsch catalyst material. These results are shown in Table 6 below and are compared with a cobalt Fischer-Tropsch catalyst for reference. Prior to the Fischer-Tropsch syntheses, the Fe-Zn Fischer-Tropsch catalyst materials were carbided according to the carbiding process described in Example 7, whereas the reference cobalt Fischer-Tropsch catalyst was reduced under hydrogen atmosphere at 300 °C. The reactions in Table 6 were carried out in a 4-fold parallel fixed bed reactor and analyzed by GC as described above in Example 5. C5+ production is reported in units of CH2gProduct / Lcat / hr.

[0172] Table 6.

[0173] Fe-Zn systems (ZnFe2O4) with low levels of sodium promoter (0.005-0.5 wt%, especially 0.005-0.2 wt%) exhibited the best performance, operating at similar reaction temperatures and reaching C5+ selectivities% of 86% — very close to the C5+ Sel% achieved with the cobalt-based reference catalyst — while maintaining low CO2selectivity. C5+ productivities per L of catalyst even exceed the productivity of the cobalt-based catalyst system. It can be further noted that addition of a low level of alkali metal promoter decreases the CH4and C2-C4selectivities without increasing the WGS activity, providing the excellent C5+ selectivity and productivities.

[0174] Even when the temperature and GHSV was increased, C5+ selectivity remained high, as described in Table 7.

[0175] Table ?.

[0176] Example 7. Influence of Carbidinq Process

[0177] To evaluate the carbiding process, different carbiding processes were performed on a catalyst material comprising 1 :1 Fe:Zn, 0.1 % Na. The reactions evaluating the carbiding process were carried out in a 4-fold parallel fixed bed reactor unit and analyzed using GC as described in Example 5. A first test carbiding process included the steps of initially reducing the sample in H2, followed by switching to syngas for the reaction testing. In this first test, the catalyst material is reduced under H2atmosphere at 400 °C, after which the temperature is decreased to 130 °C. The carbiding occurs under Fischer-Tropsch reaction conditions, wherein syngas is introduced while ramping the temperature from 130 to 200 °C at 2 °C / min. As the catalyst is carbided, conversion to C5+ products increased and stabilized. In a second testcarbiding process is a dedicated high temperature carbiding step: After an initial reduction in H2containing atmosphere, the sample was carbided for 10 hours at 350 °C in 50% CO / 50% H2; then the reactor was cooled down under the same flows to ~130 °C. Only after this dedicated carbiding step had been completed was contact with syngas for Fischer-Tropsch synthesis begun (while ramping temperature from 130 to 200 °C at 2 °C / min). These results are shown in Table 8, wherein additional reaction conditions are as follows: H2 / CO = 1.8, 16% inert, 30 bar, syngas GHSV ~5500 h’1, T = 200 °C, CO conversion ~30%.

[0178] Table 8.

[0179] As shown in Table 8, the FT synthesis was greatly improved by the dedicating carbiding step of the second carbiding process. As can be seen from Table 8, the selectivity profile for the first carbiding process is considerably worse, with higher propensity for CO2and C1-C4 hydrocarbon formation. To improve the activity of the catalyst carbided by the first carbiding process, higher temperatures would be required to reach desired CO conversions. However, with increased temperatures, the selectivity profiles deteriorate and increased CO2and C1-C4 hydrocarbon selectivities are observed at the expense of condensable C5+ hydrocarbons.

[0180] The positive performance described above is not solely due to the selection of carbiding conditions, but rather due to a combination of catalyst formulation and carbiding. As shown in Table 9, for the same high temperature carbiding pre-treatment described in Example 7, an alkali metal-free Fe-Zn catalyst still outperforms a well-studied and commonly used K- promoted precipitated bulk iron-FT catalyst (FeSiK). The reactions in Table 9 were performed in a 16-fold parallel fixed bed reactor unit, wherein two blocks of 8 tubes, each tube having an inner diameter of 2.4 mm, are independently heated and gas feed flows are equally split and distributed. The unit has hot knockout pots at 150 °C to collect high boiling waxes and coldknockout pots at 10 °C to collect water and light organics. The catalysts were loaded around 10-50 wt% in SiC. For this comparison, the reaction conditions were as follows: H2 / CO = 1.8, 16% inert, 30 bar, syngas GHSV ~5500 h’1, T = 220 °C, CO conversion ~30%.

[0181] Table 9.

[0182] The alkali metal free Fe-Zn catalyst has higher C5+ Sel% (69 vs 65 wt%), which is achieved with low CO2Sel% (5.6 vs 12.0%) at a comparable CO conversion of 30%. This is despite the fact that the FeSiK catalyst has a higher surface area (213 m2 / g) compared to the Fe-Zn catalyst (111 m2 / g).

[0183] Example 8. Comparison with Cobalt-based Fischer-Tropsch Catalyst

[0184] The obtained wax sample from the iron-zinc FT catalyst was compared to a wax sample from a reference cobalt-FT catalyst. The analysis includes simulated distillation to compare boiling point distributions, CHNO elemental analysis to compare H / C ratio and oxygen content of the wax samples. Table 10 describes the catalysts tested and compares the H / C molar ratios.

[0185] Table 10.

[0186] FIG. 5A is a graph of carbon number versus mass% per carbon number of the waxes obtained from the catalyst described in Table 10, and FIG. 5B is a picture of these waxes. As can be seen from FIG. 5A. The wax obtained from alkali metal-free Fe-FT showed very similar carbon number distribution to cobalt-derived wax. Together with similar C5+ Sel% this indicates that a similar yield of synthetic paraffinic paraffin can be expected after further hydroprocessing.The wax from alkali metal-containing iron-FT extends to slightly higher carbon numbers, which will provide beneficial properties after upgrading such as increased branching for higher a waxes. Also the H / C ratio was surprisingly similar for wax from alkali metal-free composition of Fe-FT and cobalt-FT wax, and the wax samples did not show any coloring but were very white and clean, as shown in FIG. 5B. Wax samples from iron catalysts that were promoted with a low level of Na showed slightly lower H / C ratio, indicating increased olefins content, and since alkali metal is known to increase alpha (chain growth), this was reflected by higher contribution of carbon numbers >~C35+

[0187] Example 9. Determining Zinc Remains ZnO During Reduction

[0188] The present inventors determined that Zn stays in oxide form during reduction using X-ray diffraction (XRD). XRD patterns were recorded with Co KOI ,2radiation from 30° to 103° (20) at a scan rate of 1 ,267min using a Panalytical X’Pert X-ray diffractometer. Panalytical software was used for Rietveld analysis to determine the phase composition and crystallite size.

[0189] Around 100 mg of powdered Fe-Zn catalyst material (Fe:Zn ~1 .5: 1 , no alkali) was placed in a sample holder of an Anton Parr XRK900 reaction chamber. The Fe-Zn catalyst material was dried under N2flow (30 mL / min) at 300 °C for 1 hour, ramping at 10 °C / min. Then, the Fe-Zn catalyst material was reduced under hydrogen flow (50 vol% H2in N2, 50 mL / min) at 400 °C, ramping at 1 °C / min. An initial XRD pattern is recorded at the end of this process to check that all of the iron oxide has been reduced to metallic iron. If the reduction is incomplete, reducing conditions are applied for every 2 hours until the reduction of iron oxide is complete according to the XRD pattern.

[0190] An XRD pattern showing the composition of the catalyst material prior to reduction was taken after the catalyst material was dried at 300 °C for 1 hour and then cooled to ambient temperature. The XRD pattern was recorded at ambient temperature and is shown below in FIG. 6. The peaks can be assigned to a mixture of iron ferrite and zinc oxide. The phase composition is 71 wt% iron ferrite (10 nm crystallite size) and 29 wt% zinc oxide (13 nm crystallite size) as determined by Rietveld analysis.

[0191] Another XRD pattern was recorded after the catalyst material was reduced for 4 hours at 400 °C. The XRD pattern shown below in FIG. 7 was recorded while maintaining the temperature at 400 °C and continuing the flow of 50 vol% H2in N2. The XRD pattern shows that all of the zinc ferrite had reacted, with the iron component being transformed into a mixture of wustite (FeO) and metallic iron (alpha-Fe), while the zinc component becoming additional ZnOthat did not further reduce under the conditions. The reduction was continued for an additional 2 hours, for a total of 7 hours under reducing conditions when including the time for the final XRD measurement. The changes in phase composition are detailed in below in Table 11 . The wt% of the components and their crystallite sizes were quantified by Rietveld analysis.

[0192] Table 11.The table indicates that the iron in catalyst material sample was 83 atom% reduced at the end of the initial 4 hour reduction, based on the molar composition of wustite and metallic iron. At the end of the 7 hour reduction period, the iron in the catalyst material sample was further reduced to 93 atom%.

[0193] Example 10. Mossbauer Evidence for x-Fe5C2Carbide Formation During High Temperature Carbiding Method

[0194] Two samples of ZnFe2O4catalyst material were carbided at 350 °C according to the high temperature carbiding procedure described above in Example 7. The first sample of ZnFe2O4catalyst material has an Fe:Zn ratio of 1 :1 , with 0.1 wt% Na, and the second sample of ZnFe2O4catalyst material has an Fe:Zn ratio of ~1 .5:1 , without alkali. The evolution of the iron during the carbiding process was monitored using in-situ Mossbauer spectroscopy. Around 70 mg of the ZnFe2O4catalyst material was loaded into a high-pressure Mossbauer in-situ cell equipped with high-pressure beryllium windows containing 0.08% Fe impurity. Transmission57Fe Mossbauer spectra were collected at 10 or 293 K with a sinusoidal velocity spectrometer using a57Co(Rh) source. Velocity calibration was carried out using an o-Fe foil at room temperature, and the source and absorbing samples were kept at the same temperature during the measurements. The 0.08% Fe impurities of the high-pressure beryllium windows had their spectral contribution fitted and removed from the final spectra. The Mossbauer spectra of the carbided and passivated first catalyst material taken at 10 K (top) and 293 K (bottom) are shownin FIG. 8. The Mdssbauer spectra of the carbided and passivated second catalyst material taken at 10 K (top) and 293 K (bottom) are shown in FIG. 9.

[0195] A comparison of the overall profile and shape of the obtained above Mdssbauer spectra, including fitting for the chemical shift (CS), quadrupole splitting (QS), and line width (i.e., half-width at half maximum (HWHM)) values for the doublet and sextet components are shown below in Table 12. The 3 sextet components are consistent with the presence of x-Fe5C2Carbide

[0196] Table 12.

[0197] 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 Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon;at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and the Fischer-Tropsch catalyst material includes at least 10 wt% crystalline ZnFe2O4.Embodiment 2. The Fischer-Tropsch catalyst material according to embodiment 1 , wherein the Fischer-Tropsch catalyst material comprises at least 15 wt% iron on an elemental basis exclusive of carbon, e.g., at least 20 wt% iron, or at least 25 wt% iron.Embodiment 3. The Fischer-Tropsch catalyst material according to embodiment 1 , wherein the Fischer-Tropsch catalyst material comprises at least 30 wt% iron on an elemental basis exclusive of carbon, e.g., at least 35 wt% iron, or at least 40 wt% iron.Embodiment 4. The Fischer-Tropsch catalyst material according to any of embodiments 1-3, wherein the Fischer-Tropsch catalyst material comprises at least 5 wt% zinc on an elemental basis exclusive of carbon, e.g., at least 7 wt% zinc, or at least 10 wt% zinc.Embodiment 5. The Fischer-T ropsch catalyst material according to any of embodiments 1-3, wherein the Fischer-Tropsch catalyst material comprises at least 12 wt% zinc on an elemental basis exclusive of carbon, e.g., at least 15 wt% zinc, or at least 17 wt% zinc, or at least 20 wt% zinc.Embodiment 6. The Fischer-T ropsch catalyst material according to any of embodiments 1-5, wherein the Fischer-Tropsch catalyst material comprises no more than 0.05 wt% copper on an elemental basis exclusive of carbon, e.g., no more than 0.01 wt% copper, or no more than 0.005 wt% copper, or no more than 0.001 wt% copper.Embodiment 7. The Fischer-T ropsch catalyst material according to any of embodiments 1-5, wherein the Fischer-Tropsch catalyst material is essentially free of copper.Embodiment 8. The Fischer-T ropsch catalyst material according to any of embodiments 1-7, wherein the Fischer-Tropsch catalyst material comprises 0.005-0.5 wt% copper on anelemental basis exclusive of carbon, e.g., 0.01-0.5 wt%, or 0.02-0.5 wt%, or 0.05-0.5 wt%, or 0.07-0.5 wt%, or 0.1-0.5 wt%.Embodiment 9. The Fischer-Tropsch catalyst material according to any of embodiments 1-7, wherein the Fischer-Tropsch catalyst material comprises 0.005-0.3 wt% copper on an elemental basis exclusive of carbon, e.g., 0.01-0.3 wt%, or 0.02-0.3 wt%, or 0.05-0.3 wt%, or 0.07-0.3 wt%, or 0.1-0.3 wt%.Embodiment 10. The Fischer-T ropsch catalyst material according to any of embodiments 1-7, wherein the Fischer-Tropsch catalyst material comprises 0.005-0.2 wt% copper on an elemental basis exclusive of carbon, e.g., 0.01-0.2 wt%, or 0.02-0.2 wt%, or 0.05-0.2 wt%, or 0.07-0.2 wt%, or 0.1 -0.2 wt%.Embodiment 11 . The Fischer-T ropsch catalyst material according to any of embodiments 1-7, wherein the Fischer-Tropsch catalyst material comprises 0.005-0.15 wt% copper on an elemental basis exclusive of carbon, e.g., 0.01-0.15 wt%, or 0.02-0.15 wt%, or 0.05-0.15 wt%, or 0.07-0.15 wt%.Embodiment 12. The Fischer-Tropsch catalyst material according to any of embodiments 1-11 , wherein the Fischer-Tropsch catalyst material comprises no more than 0.4 wt% alkali metal on an elemental basis exclusive of carbon, e.g., no more than 0.3 wt%.Embodiment 13. The Fischer-Tropsch catalyst material according to any of embodiments 1-11 , wherein the Fischer-Tropsch catalyst material comprises no more than 0.2 wt% alkali metal on an elemental basis exclusive of carbon, e.g., no more than 0.15 wt%.Embodiment 14. The Fischer-Tropsch catalyst material according to any of embodiments 1-11 , wherein the Fischer-Tropsch catalyst material comprises 0.005-0.5 wt% alkali metal on an elemental basis exclusive of carbon, e.g., 0.01-0.5 wt%, or 0.02-0.5 wt%, or 0.05-0.5 wt%, or 0.07-0.5 wt%, or 0.1 -0.5 wt%.Embodiment 15. The Fischer-T ropsch catalyst material according to any of embodiments 1-11 , wherein the catalyst material comprises 0.005-0.3 wt% alkali metal on an elemental basisexclusive of carbon, e.g., 0.01-0.3 wt%, or 0.02-0.3 wt%, or 0.05-0.3 wt%, or 0.07-0.3 wt%, or 0.1 -0.3 wt%.Embodiment 16. The Fischer-Tropsch catalyst material according to any of embodiments 1-11 , wherein the Fischer-Tropsch catalyst material comprises 0.005-0.2 wt% alkali metal on an elemental basis exclusive of carbon, e.g., 0.01-0.2 wt%, or 0.02-0.2 wt%, or 0.05-0.2 wt%, or 0.07-0.2 wt%, or 0.1-0.2 wt%.Embodiment 17. The Fischer-T ropsch catalyst material according to any of embodiments 1-11 , wherein the Fischer-Tropsch catalyst material comprises 0.005-0.15 wt% alkali metal on an elemental basis exclusive of carbon, e.g., 0.01-0.15 wt%, or 0.02-0.15 wt%, or 0.05-0.15 wt%, or 0.07-0.15 wt%.Embodiment 18. The Fischer-Tropsch catalyst material according to any of embodiments 1-16, wherein the alkali metal is one or more of sodium, potassium, rubidium and cesium.Embodiment 19. The Fischer-Tropsch catalyst material according to any of embodiments 1-16, wherein the alkali metal is one or more of sodium and potassium.Embodiment 20. The Fischer-Tropsch catalyst material according to any of embodiments 1-19, wherein the atomic ratio of iron to zinc is in the range of 1 :1 .5 to 20:1 , e.g., 1 : 1.2 to 20:1 , or 1 :1 to 20:1.Embodiment 21 . The Fischer-Tropsch catalyst material according to any of embodiments 1-19, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 10:1 , e.g., 1 :1 .5 to 10:1 , or 1 :1.2 to 10:1 , or 1 :1 to 10:1.Embodiment 22. The Fischer-Tropsch catalyst material according to any of embodiments 1-19, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 7:1 , e.g., 1 :1 .5 to 7:1 , or 1 :1.2 to 7:1 , or 1 :1 to 7:1.Embodiment 23. The Fischer-Tropsch catalyst material according to any of embodiments 1-19, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 5:1 , e.g., 1 :1 .5 to 5:1 , or 1 :1.2 to 5:1 , or 1 :1 to 5:1.Embodiment 24. The Fischer-Tropsch catalyst material according to any of embodiments 1-19, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 3:1 , e.g., 1 :1 .5 to 3:1 , or 1 :1.2 to 3:1 , or 1 :1 to 3:1.Embodiment 25. The Fischer-Tropsch catalyst material according to any of embodiments 1-24, wherein the Fischer-Tropsch catalyst material includes at least 20 wt% crystalline ZnFe2O4, e.g., at least 30 wt%.Embodiment 26. The Fischer-Tropsch catalyst material according to any of embodiments 1-24, wherein the Fischer-Tropsch catalyst material includes at least 40 wt% crystalline ZnFe2O4, e.g., at least 50 wt%.Embodiment 27. The Fischer-Tropsch catalyst material according to any of embodiments 1-24, wherein the Fischer-Tropsch catalyst material includes at least 60 wt% crystalline ZnFe2O4, e.g., at least 70 wt%.Embodiment 28. The Fischer-Tropsch catalyst material according to any of embodiments 1-24, wherein the Fischer-Tropsch catalyst material includes at least 80 wt% crystalline ZnFe2O4, e.g., at least 90 wt%.Embodiment 29. The Fischer-Tropsch catalyst material according to any of embodiments 1-28, wherein the crystalline ZnFe2O4has an average crystallite size in the range of 5-25 nm, e.g., in the range of 5-20 nm, or 5-15 nm, or 5-10 nm.Embodiment 30. The Fischer-Tropsch catalyst material according to any of embodiments 1-28, wherein the crystalline ZnFe2O4has an average crystallite size in the range of 8-20 nm, e.g., 8-15 nm, or 8-12 nm.Embodiment 31 . The Fischer-T ropsch catalyst material according to any of embodiments 1-28, wherein the crystalline ZnFe2O4has an average crystallite size in the range of 10-20 nm, e.g., 10-15 nm, or 10-13 nm.Embodiment 32. The Fischer-Tropsch catalyst material according to any of embodiments 1-31 , wherein at least 20 atom% of the zinc is in the form of crystalline ZnFe2O4, e.g., at least 30 wt%, or at least 40 wt%.Embodiment 33. The Fischer-Tropsch catalyst material according to any of embodiments 1-31 , wherein at least 50 atom% of the iron is in the form of crystalline ZnFe2O4, e.g., at least 60 wt%, or at least 70 wt%.Embodiment 34. The Fischer-Tropsch catalyst material according to any of embodiments 1-31 , wherein at least 80 atom% of the iron is in the form of crystalline ZnFe2O4, e.g., at least 90 wt%.Embodiment 35. The Fischer-Tropsch catalyst material according to any of embodiments 1-34, in substantially oxidic form.Embodiment 36. The Fischer-Tropsch catalyst material according to any of embodiments 1-35 wherein the Fischer-Tropsch catalyst material is an unsupported catalyst material.Embodiment 37. The Fischer-Tropsch catalyst material according to any of embodiments 1-36, wherein at least 90 wt% of the catalyst material is made up of iron and zinc, and, if present, alkali metal and / or copper, e.g., at least 95 wt%, or at least 98 wt%, or at least 99 wt%, or at least 99.5 wt%, or at least 99.8 wt%, on an elemental basis exclusive of carbon.Embodiment 38. The Fischer-Tropsch catalyst material according to any of embodiments 1-35, wherein the Fischer-Tropsch catalyst material is a supported catalyst material.Embodiment 39. The Fischer-Tropsch catalyst material according to embodiment 38, wherein the Fischer-Tropsch catalyst material further comprises a support that supports the iron and zinc and, if present, alkali metal and / or copper.Embodiment 40. The Fischer-Tropsch catalyst material according to any of embodiments 1-35, 38 and 39, wherein at least 90 wt% of the Fischer-Tropsch catalyst material is made up of iron, zinc, alkali metal, copper, and the support, e.g., at least 95 wt%, or at least 98 wt%, or atleast 99 wt%, or at least 99.5 wt%, or at least 99.8 wt%, on an elemental basis exclusive of carbon.Embodiment 41 . The Fischer-Tropsch catalyst material according to embodiment 39 or 40 wherein the support is formed of a refractory oxide.Embodiment 42. A process for making a Fischer-Tropsch catalyst material according to any of claims 1-41 , the process comprising: providing one or more first liquids each comprising one or more iron-containing and / or one or more zinc-containing compounds dissolved in one or more first solvents; contacting the one or more first liquids with precipitating ions in the presence of alkali metal ions to provide an alkali-containing precipitate and a supernatant; isolating the alkali-containing precipitate from the supernatant; optionally, washing the isolated precipitate with a washing liquid to reduce concentration of alkali metal thereof; and calcining the isolated precipitate to provide the Fischer-Tropsch catalyst material.Embodiment 43. The process of embodiment 42, wherein the iron-containing compounds and zinc-containing compounds are selected from water-soluble metal salts (e.g., nitrates and acetates).Embodiment 44. The process of embodiment 42 or embodiment 43, wherein each of the one or more first solvents is an aqueous fluid, e.g., water.Embodiment 45. The process of any of embodiments 42-44, wherein each of the one or more first liquids has a pH of no greater than 7.Embodiment 46. The process of any of embodiments 42-45, wherein the precipitating ions comprise carbonate ions and / or hydroxide ions.Embodiment 47. The process of any of embodiments 42-46, wherein the precipitating ions are provided as an alkali metal base, e.g., a carbonate or a hydroxide.Embodiment 48. The process of any of embodiments 42-47, wherein the precipitating ions are provided as a non-metal containing base, e.g., ammonium carbonate or ammonium hydroxide.Embodiment 49. The process of embodiment 48, wherein the alkali metal ions are provided by an alkali metal salt.Embodiment 50. The process of any of embodiments 42-49, wherein the contacting of the one or more first liquids with the precipitating ions is performed at a precipitation pH that is alkaline.Embodiment 51 . The process of any of embodiments 42-50, wherein the contacting of the one or more first liquids with the precipitating ions is performed at precipitation pH in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9-12, or 9-11 , or 9- 10..Embodiment 52. The process of any of embodiment 50 or embodiment 51 , wherein the process further comprises maintaining the pH of the contacting step at an alkaline pH, for example, in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9-12, or 9-11 , or 9-10.Embodiment 53. The process of embodiment 52, wherein the pH of the contacting step is maintained by controlling a rate of addition of precipitating ions.Embodiment 54. The process of any of embodiments 42-53, wherein the contacting step is conducted at an elevated temperature (e.g., in the range of 60-100 °C, or 60-90 °C, or 60-80 °C, or 70-100 °C, or 70-90 °C, or 70-80 °C.).Embodiment 55. The process of any of embodiments 42-54, wherein the process further comprising aging the alkali-containing precipitate in contact with the supernatant (e.g., before isolation).Embodiment 56. The process of any of embodiments 42-55, wherein the washing the isolated precipitate with an aqueous washing liquid to reduce concentration of alkali metal thereof is performed.Embodiment 57. The process of embodiment 56, wherein washing the precipitate is repeated until a desired level of alkali metal is provided to the Fischer-Tropsch catalyst material.Embodiment 58. The process of any of embodiments 42-57, wherein the process further comprises drying the isolated precipitate before the calcining.Embodiment 59. The process of any of embodiments 42-58, wherein the calcining is conducted for a time in the range of 0.5 to 24 hours (e.g., in the range of 0.5 to 15 hours, or 0.5 to 10 hours, or 0.5 to 5 hours).Embodiment 60. The process of any of embodiments 42-59, wherein calcining is conducted at a temperature is in the range of 100-600 °C, e.g., in the range of 200-600 °C, or 300-600 °C, or 100-500 °C, or 200-500 °C, or 300-500 °C.Embodiment 61 . A process for making a Fischer-Tropsch catalyst material according to any of claims 1-41 , the process comprising: providing one or more first liquids each comprising one or more iron-containing and / or one or more zinc-containing compounds dissolved in one or more first solvents; contacting the one or more first liquids with precipitating ions in the substantial absence of alkali metal ions to provide a substantially alkali-free precipitate and a supernatant; isolating the substantially alkali-free precipitate from the supernatant; optionally, adding alkali metal ions to the substantially alkali-free precipitate in order to provide an alkali-containing precipitate; and calcining the isolated precipitate to provide the Fischer-Tropsch catalyst material.Embodiment 62. The process of embodiment 61 , wherein the iron-containing compounds and zinc-containing compounds are selected from water-soluble metal salts (e.g., nitrates and acetates).Embodiment 63. The process of embodiment 61 or embodiment 62, wherein each of the one or more first solvents is an aqueous fluid, e.g., water.Embodiment 64. The process of any of embodiments 61-63, wherein each of the one or more first liquids has a pH of no greater than 7.Embodiment 65. The process of any of embodiments 61-64, wherein the precipitating ions comprise carbonate ions and / or hydroxide ions.Embodiment 66. The process of any of embodiments 61-65, wherein the precipitating ions are provided as a non-metal containing base, e.g., ammonium carbonate or ammonium hydroxide.Embodiment 67. The process of any of embodiments 61-66, wherein the contacting of the one or more first liquids with the precipitating ions is performed at a precipitation pH that is alkaline.Embodiment 68. The process of any of embodiments 61-67, wherein the contacting of the one or more first liquids with the precipitating ions is performed at precipitation pH in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9- 12, or 9-11 , or 9-10..Embodiment 69. The process of any of embodiment 67 or embodiment 68, wherein the process further comprises maintaining the pH of the contacting step at an alkaline pH, for example, in the range of 8-12, e.g., in the range of 8-11 , or 8-10, or 8.5-12, or 8.5-11 , or 8.5-10, or 9-12, or 9-11 , or 9-10.Embodiment 70. The process of embodiment 69, wherein the pH of the contacting step is maintained by controlling a rate of addition of precipitating ions.Embodiment 71. The process of any of embodiments 61-70, wherein the contacting step is conducted at an elevated temperature (e.g., in the range of 60-100 °C, or 60-90 °C, or 60-80 °C, or 70-100 °C, or 70-90 °C, or 70-80 °C.).Embodiment 72. The process of any of embodiments 61-71 , wherein the process further comprising aging the substantially alkali-free precipitate in contact with the supernatant (e.g., before isolation).Embodiment 73. The process of any of embodiments 61-72, further comprising washing the isolated precipitate with a washing liquid.Embodiment 74. The process of any of embodiments 61-73, wherein the process further comprises drying the isolated precipitate before the calcining.Embodiment 75. The process of any of embodiments 61-74, wherein the calcining is conducted for a time in the range of 0.5 to 24 hours (e.g., in the range of 0.5 to 15 hours, or 0.5 to 10 hours, or 0.5 to 5 hours).Embodiment 76. The process of any of embodiments 61-75, wherein calcining is conducted at a temperature is in the range of 100-600 °C, e.g., in the range of 200-600 °C, or 300-600 °C, or 100-500 °C, or 200-500 °C, or 300-500 °C.Embodiment 77. The process of any of embodiments 61-76, wherein adding alkali metal ions to the substantially alkali-free precipitate in order to provide an alkali-containing precipitate is performed before calcining the precipitate.Embodiment 78 A carbided Fischer-Tropsch catalyst material, that is the Fischer-Tropsch catalyst material of any of embodiments 1-41 , or a Fischer-Tropsch catalyst material made by a process of any of claims 42-77, in carbided form.Embodiment 79. A carbided Fischer-Tropsch catalyst material of Embodiment 78, wherein at least 50 atom% of the iron is in a carbide form.Embodiment 80. A carbided Fischer-Tropsch catalyst material comprising: at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon,wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in the form of iron carbide.Embodiment 81 . The carbided Fischer-Tropsch catalyst material of Embodiment 79 or Embodiment 80, wherein at least 60 atom% of the iron is in a carbide form, e.g., at least 70 atom%, or at least 80 atom%, or at least 90 atom%.Embodiment 82. The carbided Fischer-Tropsch catalyst material of Embodiment 79 or Embodiment 80, wherein in the range of 50-99 atom% of the iron is in a carbide form, e.g., in the range of 50-95%, or 50-90%, or 50-85%.Embodiment 83. The carbided Fischer-Tropsch catalyst material of Embodiment 79 or Embodiment 80, wherein in the range of 60-99 atom% of the iron is in a carbide form, e.g., in the range of 60-95%, or 60-90%, or 60-85%.Embodiment 84. The carbided Fischer-Tropsch catalyst material of Embodiment 79 or Embodiment 80, wherein in the range of 70-99 atom% of the iron is in a carbide form, e.g., in the range of 70-95%, or 70-90%.Embodiment 85. The carbided Fischer-Tropsch catalyst material of Embodiment 79 or Embodiment 80, wherein in the range of 80-99 atom% of the iron is in a carbide form, e.g., in the range of 80-95%, or 80-90%.Embodiment 86. The carbided Fischer-Tropsch catalyst material of Embodiment 79 or Embodiment 80, wherein in the range of 90-99 atom% of the iron is in a carbide form, e.g., in the range of 90-98%, or 90-95%.Embodiment 87. The carbided Fischer-T ropsch catalyst material of any of Embodiments 78-86, wherein no more than 20 atom% of iron is in oxidic form, e.g., no more than 10 atom%.Embodiment 88. The carbided Fischer-T ropsch catalyst material of any of Embodiments 78-86, wherein no more than 5 atom% of iron is in oxidic form, e.g., no more than 2 atom%.Embodiment 89. The carbided Fischer-Tropsch catalyst material of Embodiment 94 orEmbodiment 88, used in a Fischer-Tropsch synthesis having a feed CO2 / CO ratio no more than 0.5, e.g., no more than 0.2Embodiment 90. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-89, wherein at least 5 atom% of the iron is in an oxide phase, e.g., at least 10 atom%, or at least 15 atom%, or at least 20 atom%.Embodiment 91 . The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-89, wherein in the range of 5-50 atom% of the iron is in an oxide phase, e.g., 5-45 atom%, or 5-40 atom%.Embodiment 92. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-89, wherein in the range of 10-50 atom% of the iron is in an oxide phase, e.g., 10-45 atom%, or 10-40 atom%.Embodiment 93. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-89, wherein in the range of 15-50 atom% of the iron is in an oxide phase, e.g., 15-45 atom%, or 15-40 atom%.Embodiment 94. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-89, wherein in the range of 20-50 atom% of the iron is in an oxide phase, e.g., 20-45 atom%, or 20-40 atom%.Embodiment 95. The carbided Fischer-T ropsch catalyst material of any of embodiments 78-94, used in a Fischer-Tropsch synthesis having a feed CO2 / CO ratio in excess of 0.5, e.g., in excess of 1 .Embodiment 96. The carbided Fischer-Tropsch catalyst material of any of embodiments 78-95, wherein the amount of iron is as described in any of Embodiments 2-3.Embodiment 97. The carbided Fischer-Tropsch catalyst material of any of embodiments 78-96, wherein the amount of zinc is as described in any of Embodiments 4-5.Embodiment 98. The carbided Fischer-Tropsch catalyst material of any of embodiments 78-97, wherein the amount of copper is as described in any of Embodiments 6-11 .Embodiment 99. The carbided Fischer-Tropsch catalyst material of any of embodiments 78-98, wherein the amount of alkali metal is as described in any of Embodiments 12-19.Embodiment 100. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-99, wherein the alkali metal is as described in any of Embodiments 18-19.Embodiment 101. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-100, wherein the atomic ratio of iron to zinc is as described in any of Embodiments 9-13.Embodiment 102. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-101 , wherein the carbided Fischer-Tropsch catalyst material is an unsupported catalyst material.Embodiment 103. The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-102, wherein at least 90 wt% of the catalyst material is made up of iron, zinc, and, if present, alkali metal and / or copper, e.g., at least 95 wt%, or at least 98 wt%, or at least 99 wt%, or at least 99.5 wt%, or at least 99.8 wt%, on an elemental basis exclusive of carbon.Embodiment 104 The carbided Fischer-Tropsch catalyst material of any of Embodiments 78-103, wherein the carbided Fischer-Tropsch catalyst material is a supported catalyst material.Embodiment 105. The carbided Fischer-Tropsch catalyst material according to embodiment 104, wherein the Fischer-Tropsch catalyst material further comprises a support that supports the iron and zinc and, if present, alkali metal and / or copper.Embodiment 106. The carbided Fischer-Tropsch catalyst material according to Embodiment 104 or embodiment 105, wherein at least 90 wt% of the Fischer-T ropsch catalyst material is made up of iron, zinc and the support, and, if present, alkali metal and / or copper, e.g., at least 95 wt%, or at least 98 wt%, or at least 99 wt%, or at least 99.5 wt%, or at least 99.8 wt%, on an elemental basis exclusive of carbon.Embodiment 107. The carbided Fischer-Tropsch catalyst material according to embodiment 105 or embodiment 106, wherein the support is formed of a refractory oxide.Embodiment 108. The carbided Fischer-T ropsch catalyst material of any of embodiments 78-107, comprising x-Fe5C2.Embodiment 109. The carbided Fischer-Tropsch catalyst material of embodiment 108, wherein at least 50 atom% of the carbided iron of the carbided Fischer-Tropsch catalyst material is in the form of x-Fe5C2, e.g., at least 60 wt%, or at least 70 wt%.Embodiment 110. The carbided Fischer-T ropsch catalyst material of embodiment 108, wherein at least 75 atom% of the carbided iron of the carbided Fischer-Tropsch catalyst material is in the form of x-Fe5C2, e.g., at least 80 wt%.Embodiment 111. The carbided Fischer-T ropsch catalyst material of embodiment 108, wherein at least 85 atom% of the carbided iron of the carbided Fischer-Tropsch catalyst material is in the form of x-Fe5C2, e.g., at least 90 wt%.Embodiment 112. A process for providing a carbided Fischer-Tropsch catalyst material of any of Embodiments 78-111 , the process comprising carbiding a catalyst material of any of embodiments 1-41 or a catalyst material made by a process of any of claims 42-77 to provide the carbided Fischer-Tropsch catalyst material.Embodiment 113. The process of Embodiment 112, wherein the carbiding the Fischer- Tropsch catalyst material to provide the carbided Fischer-Tropsch catalyst material comprises optionally, treating the Fischer-Tropsch catalyst material with a reducing gas stream comprising hydrogen for a time and at a temperature sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in metallic form; then . treating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide (e.g., carbon monoxide), at a temperature of at least 180 °C for a time sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in carbided form, e.g., for at least 5 hoursEmbodiment 114. The process of embodiment 113, wherein the treatment of the Fischer-Tropsch catalyst material with the reducing gas stream is not performed.Embodiment 115. The process of embodiment 113, wherein the treatment of the Fischer- Tropsch catalyst with the reducing gas stream is performed.Embodiment 116. The process of embodiment 115, wherein the treating of the catalyst material with the reducing gas stream comprising hydrogen is performed in the substantial absence of carbon monoxide.Embodiment 117. The process of embodiment 115 or embodiment 116, wherein the reducing gas stream further comprises an inert gas (e.g., nitrogen).Embodiment 118. The process of embodiment 117, wherein the hydrogen and inert gas are present in the reducing gas stream in a ratio of at least 1 :1.Embodiment 119. The process of any of embodiments 115-118, wherein treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted at a temperature in the range of 250-650 °C (e.g., in the range of 250-600 °C, or 250-550 °C, or 250-500 °C).Embodiment 120. The process of any of embodiments 115-118, wherein treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted at a temperature in the range of 300-650 °C (e.g., in the range of 300-600 °C, or 300-550 °C, or 300-500 °C).Embodiment 121 . The process of any of embodiments 115-118, wherein treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted at a temperature in the range of 350-650 °C (e.g., in the range of 350-600 °C, or 350-550 °C, or 350-500 °C).Embodiment 122. The process of any of embodiments 115-121 , wherein treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted for a time of at least 12 hours, e.g., at least 14 hours.Embodiment 123. The process of any of embodiments 115-121 , wherein treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted for a time in the range of 12 to 30 hours (e.g., 12 to 24 hours, or 14 to 30 hours, or 14 to 24 hours).Embodiment 124. The process of any of embodiments 115-123, wherein the treatment with the reducing gas stream is performed to provide a catalyst material in which at least 60 atom% of the iron is in reduced form, e.g., at least 70 atom%.Embodiment 125. The process of any of embodiments 115-123, wherein the treatment with the reducing gas stream is performed to provide a catalyst material in which at least 80 atom% of the iron is in reduced form, e.g., at least 85 atom%.Embodiment 126. The process of any of embodiments 115-125, wherein the carbiding gas stream comprises carbon monoxide.Embodiment 127. The process of any of embodiments 115-125, (particularly 114 and 126) wherein the carbiding gas stream further comprises hydrogen.Embodiment 128. The process of embodiment 127, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide) of at least 1 :1 (e.g., at least 2:1 , or at least 5:1 , or at least 10:1 , or at least 15:1 , or at least 20:1 , or at least 25:1 , or at least 30:1).Embodiment 129. The process of embodiment 127, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide) of 1 :1 to 100:1 , e.g., in the range of 2:1 to 100:1 , or 5:1 to 100:1 , or 10:1 to 100:1 , or 15:1 to 100:1 , or 20:1 to 100:1 , or 25:1 to 100:1 , or 30:1 to 100:1.Embodiment 130. The process of embodiment 127, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of hydrogen to carbon monoxide and carbon dioxide (e.g., hydrogen to carbon monoxide) of 1 :1 to 50:1 , e.g., inthe range of 2:1 to 50:1 , or 5:1 to 50:1 , or 10:1 to 50:1 , or 15:1 to 50:1 , or 20:1 to 50:1 , or 25:1 to 50:1 , or 30:1 to 50:1 .Embodiment 131. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature of at least 200 °C, e.g., at least 220 °C.Embodiment 132. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 180-450 °C (e.g., in the range of 180-400 °C, or 180-350°C, or 180-300 °C).Embodiment 133. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 200-450 °C (e.g., in the range of 200-400 °C, or 200-350°C, or 200-300 °C).Embodiment 134. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 220-450 °C (e.g., in the range of 220-400 °C, or 220-350 °C, or 220-300 °C).Embodiment 135. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature of at least 300 °C, e.g., at least 325 °C, or at least 350 °C, or at least 375 °C, or at least 400 °C.Embodiment 136. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 300-650 °C, e.g., 300-600 °C, or 300-550 °C or 300-500 °C.Embodiment 137. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 325-650 °C, e.g., 325-600 °C, or 325-550 °C, or 325-500 °CEmbodiment 138. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 350-650 °C, e.g., 350-600 °C, or 350-550 °C or 350-500 °C.Embodiment 139. The process of any of embodiments 113-130, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 375-650 °C, e.g., 375-600 °C, or 375-550 °C, or 375-500 °C.Embodiment 140. The process of any of embodiments 113-130, wherein treating theFischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 400-650 °C, e.g., 400-600 °C, or 400-550 °C, or 400-500 °CEmbodiment 141 . The process of any of embodiments 113-140, wherein treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted for a time in the range of 3-20 hours, e.g., 5-20 hours, or 3-15 hours, or 5-15 hours.Embodiment 142. A process for performing a Fischer-Tropsch synthesis, the process comprising providing a carbided Fischer-Tropsch catalyst material of any of embodiments 78-111 , or a carbided catalyst material made by the process of any of embodiments 112-141 ; contacting at a reaction temperature and pressure the Fischer-Tropsch catalyst material with a feed stream comprising H2and CO to provide a product stream comprising C5+ hydrocarbons.Embodiment 143. The process of embodiment 142, wherein the feed stream has a H2:CO ratio in the range of 0.5:1 to 6:1 .Embodiment 144. The process of embodiment 142 or embodiment 143, wherein the feed stream has a H2:CO ratio in the range of 1 :1 to 3:1 , e.g., 1 :1 to 2.5:1.Embodiment 145. The process of embodiment 142 or embodiment 143, wherein the feed stream has a H2:CO ratio of at least 1.4:1 , e.g., in the range of 1.4:1 to 3:1 , or 1.4:1 to 2.5:1.Embodiment 146. The process of embodiment 142 or embodiment 143, wherein the feed stream has a H2:CO ratio of at least 2:1 , e.g., in the range of 2:1 to 6:1 , or in the range of 2:1 to 4:1.Embodiment 147. The process of any of embodiments 142-146, wherein the feed stream includes up to 80% of one or more inerts, 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%.Embodiment 148. The process of any of embodiments 142-147, wherein the feed stream includes up to 80% of one or more inerts selected from methane and nitrogen, 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%.Embodiment 149. The process of any of embodiments 142-148, wherein the feed stream includes up to 80% 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%.Embodiment 150. The process of embodiment 149, wherein the molar ratio of CO2to CO in the feed stream is at least 0.5:1 , e.g., at least 0.7:1 or at least 1 :1.Embodiment 151. The process of any of embodiments 142-149, wherein the molar ratio of CO2to CO in the feed stream is no more than 0.5, e.g., no more than 0.3.Embodiment 152. The process of any of embodiments 142-149, wherein the molar ratio of CO2to CO in the feed stream is no more than 0.15, e.g., no more than 0.1 , or no more than 0.05.Embodiment 153. The process of any of embodiments 142-152, wherein the 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%.Embodiment 154. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 150-400 °C, e.g., in the range of 150-350 °C, or 150-300 °C, or 150-290 °C, or 150-280 °C, or 150-265 °C, or 150-250 °C, or 150-200 °C.Embodiment 155. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 180-400 °C, e.g., in the range of 180-350 °C, or 180-300 °C, or 180-280 °C, or 180-265 °C, or 180-250 °C, or 180-225 °C, or 180-200 °C.Embodiment 156. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 200-400 °C, e.g., in the range of 200-350 °C, or 200-300 °C, or 200-280 °C, or 200-265 °C, or 200-250 °C, or 200-225 °C.Embodiment 157. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 220-400 °C, e.g., in the range of 220-350 °C, or 220-300 °C, or 220-280 °C, or 220-265 °C, or 220-250 °C.Embodiment 158. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 250-400 °C, e.g., in the range of 250-350 °C, or 250-300 °C, or 250-280 °C.Embodiment 159. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 300-400 °C.Embodiment 160. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 200-350 °C.Embodiment 161. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 200-280 °C.Embodiment 162. The process of any of embodiments 142-153, wherein the reaction temperature is in the range of 200-250 °C.Embodiment 163. The process of any of embodiments 142-162, wherein the pressure is in the range of 10-50 barg (e.g., 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).Embodiment 164. The process of any of embodiments 142-162, wherein the pressure is in the range of 20-50 barg.Embodiment 165. The process of any of embodiments 142-164, wherein the Fischer- Tropsch reaction is conducted at a GHSV in the range of 1 ,000 to 2,000,000 h’1(e.g., in therange of 1 ,000 to 1 ,200,000 h’1, or 1 ,000 to 500,000 h’1, or 1 ,000 to 100,000 h’1, or 5,000 to 1 ,200,000 IT1, or 5,000 to 500,000 h’1, or 5,000 to 100,000 h’1, or 10,000 to 1 ,200,000 h’1, or 10,000 to 500,000 h’1, or 10,000 to 100,000 h’1).Embodiment 166. The process of any of embodiments 142-165, wherein the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C5+ selectivity of at least 30%, e.g., at least 40%, or at least 50%.Embodiment 167. The process of any of embodiments 142-166, wherein the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C5+ selectivity of at least 60%, e.g., at least 60%, or at least 80%.Embodiment 168. The process of any of embodiments 142-167, wherein the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-4 selectivity of no more than 30%, e.g., no more than 25%, or no more than 20%.Embodiment 169. The process of any of embodiments 142-168, wherein the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a methane selectivity of no more than 20%, e.g., no more than 15%, or no more than 10%, or no more than 5%.Embodiment 170. The process of any of embodiments 142-169, wherein the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity of no more than 30%, e.g., no more than 25%, or no more than 20%.Embodiment 171. The process of any of embodiments 142-157, wherein the contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity of no more than 15%, e.g., no more than 10%, or no more than 5%.Embodiment 172. The process of any of embodiments 142-159, further comprising separating at least a portion of C1-C4 hydrocarbons from the product stream to provide a light hydrocarbon stream.Embodiment 173. The process of embodiment 172, further comprising burning at least a portion of the light hydrocarbon stream to provide energy, e.g., heat energy or electrical energy.Embodiment 174. The process of embodiment 173, wherein the heat energy is used to heat the feed stream.Embodiment 175. The process of any of embodiments 142-174, further comprising recycling at least a portion of H2of the product stream to the feed stream.Embodiment 176. The process of any of embodiments 142-175, further comprising recycling at least a portion of CO of the product stream to the feed stream.Embodiment 177. The process of any of embodiments 142-176, further comprising recycling at least a portion of inerts of the product stream to the feed stream.Embodiment 178. The process of any of embodiments 142-177, wherein one or more products are provided from at least a portion of C5+ hydrocarbons of the product stream.Embodiment 179. The process of embodiment 178, wherein the one or more products include fuels (e.g., gasoline, diesel fuel, aviation fuel), lubricants and waxes.Embodiment 180. The process of any of embodiments 142-179, further comprising hydroprocessing at least a portion of C5+ hydrocarbons of the product stream.Embodiment 181. The process of any of embodiments 142-180, wherein at least part of the H2of the feed stream is from a renewable source.Embodiment 182. The process of any of embodiment 142-180, wherein at least a portion of the hydrogen of the feed stream is green hydrogen.Embodiment 183. The process of any of embodiment 142-180, wherein at least a portion of the hydrogen of the feed stream is blue hydrogen.Embodiment 184. The process of any of embodiment 142-180, wherein at least a portion of the hydrogen of the first feed stream or the second feed stream is grey hydrogen, black hydrogen, brown hydrogen, pink hydrogen, turquoise hydrogen, yellow hydrogen, and / or white hydrogen.Embodiment 185. The process of any of embodiments 142-184, further comprising providing at least a portion of H2to the first feed stream and / or the second feed stream by electrolysis of water.Embodiment 186. The process of embodiment 185, wherein the electrolysis of water is performed using at least partially electricity from a renewable source.Embodiment 187. The process of embodiment 185 or embodiment 186, wherein the electrolysis of water is performed using at least partially electricity generated from steam made by heat exchange from the first product stream and / or the second product stream, or by burning a light hydrocarbon stream (e.g., methane from biogas).

[0198] 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.

[0199] 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 method of referring individually to each separate value falling within the range. Unless otherwise indicatedherein, 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.

[0200] 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 nonclaimed element essential to the practice of the invention.

[0201] 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.

[0202] 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.

[0203] 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.

[0204] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specificexamples 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.

[0205] 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.

[0206] 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.

[0207] 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 performing a Fischer-Tropsch synthesis, the process comprising providing a carbided Fischer-Tropsch catalyst material comprising: at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in the form of iron carbide; and contacting at a reaction temperature in the range of 180-280 C and a reaction pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2and CO to provide a product stream comprising C5+ hydrocarbons.Claim 2. The process according to Claim 1 , wherein the carbided Fischer-Tropsch catalyst material comprises at least 30 wt% iron on an elemental basis exclusive of carbon and / or at least 7 wt% zinc on an elemental basis exclusive of carbon.Claim 3. The process according to Claim 1 or Claim 2, wherein the carbided Fischer- Tropsch catalyst material comprises no more than 0.01 wt% copper on an elemental basis exclusive of carbon.Claim 4. The process according to any of Claims 1-3, wherein the carbided Fischer- Tropsch catalyst material comprises no more than 0.15 wt% alkali metal on an elemental basis exclusive of carbon.Claim 5. The process according to any of Claims 1-4, wherein at least 95 wt% of the carbided Fischer-Tropsch catalyst material is made up of iron and zinc, and, if present, alkali metal and / or copper, e.g., at least 95 wt%, or at least 98 wt%, or at least 99 wt%, or at least 99.5 wt%, or at least 99.8 wt%, on an elemental basis exclusive of carbon.Claim 6. The process of any of Claims 1-5, wherein the in the carbided Fischer-Tropsch catalyst material in the range of 60-90 atom% of the iron is in a carbide form.Claim 7. The process of any of Claims 1-6, wherein in the carbided Fischer-Tropsch catalyst material at least 70 atom% of the carbided iron of the carbided Fischer-Tropsch catalyst material is in the form of x-Fe5C2Claim 8. The process of any of Claims 1-7, wherein the carbided Fischer-Tropsch catalyst material is prepared by a process comprising comprising providing a Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and the Fischer-Tropsch catalyst material includes at least 10 wt% crystalline ZnFe2O4; and carbiding the Fischer-Tropsch catalyst material to provide the carbided Fischer-Tropsch catalyst material by operations comprising: optionally, treating the Fischer-Tropsch catalyst material with a reducing gas stream comprising hydrogen for a time and at a temperature sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in metallic form; then treating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide (e.g., carbon monoxide), at a temperature of at least 180 °C for a time sufficient to provide at least 50 atom% of the iron of the Fischer-Tropsch catalyst material in carbided form, e.g., for at least 5 hoursClaim 9. The process of Claim 8, wherein treating the Fischer-Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the range of 300-650 °C.Claim 10. The process of any of Claims 1-9, wherein the contacting of the carbided Fischer-Tropsch catalyst material with the feed stream comprising H2and CO is conducted at a temperature in the range of 200-250 C.Claim 11. The process of any of Claims 1-10, wherein the molar ratio of CO2to CO in the feed stream is more than 0.3.Claim 12. A Fischer-Tropsch catalyst material comprising at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, wherein the atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , the Fischer-Tropsch catalyst material includes at least 70 wt% crystalline ZnFe2O4, and the crystalline ZnFe2O4has an average crystallite size in the range of 5-25 nmClaim 13. The Fischer-Tropsch catalyst material according to Claim 12, wherein at least 50 atom% of the iron is in the form of crystalline ZnFe2O4.Claim 14. The Fischer-Tropsch catalyst material according to Claim 12 or Claim 13, wherein the carbided Fischer-Tropsch catalyst material comprises no more than 0.01 wt% copper on an elemental basis exclusive of carbon, and no more than 0.15 wt% alkali metal on an elemental basis exclusive of carbon.Claim 15. A carbided Fischer-Tropsch catalyst material, that is the Fischer-Tropsch catalyst material of Claim 12 or Claim 13 in carbided from, the carbided Fischer-Tropsch catalyst material comprising: at least 10 wt% iron, on an elemental basis exclusive of carbon; at least 3 wt% zinc, on an elemental basis exclusive of carbon; no more than 0.1 wt% copper, on an elemental basis exclusive of carbon; and no more than 0.5 wt% alkali metal, on an elemental basis exclusive of carbon, whereinthe atomic ratio of iron to zinc is in the range of 1 :2 to 20:1 , and at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in the form of iron carbide.

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