Carbided iron-based fischer-tropsch catalysts and processes for making and using same

Abstract

The present disclosure provides carbided iron-based Fischer-Tropsch catalyst materials having various carbide phases, various low- and high-temperature carbiding processes for making such carbided Fischer-Tropsch catalyst materials, and Fischer-Tropsch processes using such carbided Fischer-Tropsch catalyst materials.

Description

CARBIDED IRON-BASED FISCHER-TROPSCH CATALYSTS AND PROCESSES FOR MAKING AND USING SAMECROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority U.S. provisional application number 63 / 616,373, filed December 29, 2023 and European Patent application number 24166560.3, 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 Fischer-Tropsch 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-gas shift (WGS) activity. The water-gas shift reaction competes with the Fischer-Tropsch process by converting CO and H2O to CO2 and hydrogen, as shown below:CO + H2O co2+ H2Accordingly, higher WGS activity leads to high CO2 yields 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 based on ironbased FT processes.SUMMARY

[0007] In one aspect, the present disclosure provides a process for providing a carbided Fischer-Tropsch catalyst material, the process comprising: providing a Fischer-Tropsch catalyst material comprising iron; 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 300 °C for a time sufficient to provide a carbided Fischer- Tropsch catalyst material having at least 50 atom% of its iron in carbided form.

[0008] In another aspect, the disclosure provides a carbided Fischer-Tropsch catalyst material comprising at least 10 wt% iron on an elemental basis exclusive of carbon, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 45 atom%.

[0009] In another aspect, the disclosure provides a process for providing a carbided Fischer-Tropsch catalyst material, the process comprising: providing a Fischer-Tropsch catalyst material comprising iron, 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 in the range of 160-300 °C for a time sufficient to provide a carbided Fischer-Tropsch catalyst material having at least 50 atom% of its iron in carbided form.

[0010] In another aspect, the disclosure provides a carbided Fischer-Tropsch catalyst material comprising at least 10 wt% iron on an elemental basis exclusive of carbon, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the carbided Fischer-Tropsch catalystmaterial that is in a carbide form is in the form of one or more of e-Fe3C and r|-Fe3C, e.g., at least 45 atom%.

[0011] In another aspect, the disclosure provides a process for performing a Fischer- Tropsch synthesis, the process comprising providing a carbided Fischer-Tropsch catalyst material as described herein, or a catalyst material made by a process as described herein; contacting at a reaction temperature and pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2and CO to provide a product stream comprising Cs+ hydrocarbons.

[0012] Other aspects of the disclosure will be apparent to the person of ordinary skill in the art based on the description herein.BRIEF DESCRIPTION OF FIGURES

[0013] 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.

[0014] FIG. 1 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0015] FIG. 2 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0016] FIG. 3 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0017] FIG. 4 is a schematic of a process for performing a Fischer-Tropsch process as described herein.

[0018] FIG. 5 is an X-ray diffraction pattern of a calcined Fischer-Tropsch catalyst material as described herein.

[0019] FIG. 6 is a set of Mdssbauer spectra of Fischer-Tropsch catalyst materials activated by carbiding processes as described herein.

[0020] FIG. 7 is a set of Mdssbauer spectra of Fischer-Tropsch catalyst materials activated by carbiding processes as described herein.DETAILED DESCRIPTION

[0021] The iron-catalysed Fischer Tropsch (FT) process converts syngas (CO + H2) to long-chain hydrocarbon products which can be upgraded (e.g., via cracking / hydrotreating) to make fuels, base oils, lubricants or other products. The present inventors have noted that iron-based Fischer-Tropsch catalysts have advantages over cobalt-based FT catalysts in terms of economics (lower cost of earth-abundant iron vs cobalt, by factor -200-1000) and sustainability (with respect to resource scarcity and mining of cobalt oxides). But in contrast to cobalt, iron-based catalysts generally exhibit a much high water gas shift (WGS) activity, which provides typically undesirable conversion of CO of the feed to CO2, and thus to higher CO2yields and lower conversion of the feedstock carbon into fungible C5+ hydrocarbons.

[0022] Selectively producing higher alcohols can be an attractive strategy of increasing the value of the hydrocarbon stream from Fischer-Tropsch synthesis, due to the high value of alcohols as intermediates for speciality chemical production. However, certain markets may desire to suppress the selectivity towards oxygenates. For example, in fuel applications there are limits on oxygen content exist and oxygenates may be less desired based on their lower volatility and stability as compared with paraffins. Similarly, if the Fischer-Tropsch synthesis produces oxygenates, based on their higher polarity, these will to some extent dissolve in the water produced during the reaction. This can lead to increased Chemical Oxygen Demand (COD) for wastewater treatment, and, if the produced oxygenates contain carboxylic acids, a higher total acid number (TAN) of the liquid hydrocarbon and aqueous phase can increase treatment cost and equipment cost if higher corrosion resistant materials are required.

[0023] Conventionally, iron-containing catalyst materials are typically prepared for use as active 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 catalyst material to metallic iron. Then, when exposed to Fischer-Tropsch reaction conditions, a substantial part of this iron is converted to iron carbide. It is thus not conventionally necessary to provide a separate carbiding treatment; rather, the carbiding is a natural result of reaction conditions. However, such Fischer-Tropsch processes tend to exhibit a relatively higher degree of water-gas shift activity, and thus convert carbon monoxide by reaction with hydrogen to carbon dioxide and water. This results in a relatively lower conversion of carbon monoxide to desirable C5+ products. Moreover, such Fischer- Tropsch processes tend to form a relatively high degree of oxygenates, which, as noted above, may in some cases be less desirable products.

[0024] The present inventors have determined that catalyst carbiding can be performed in such a manner so as to increase olefin selectivity and reduce water-gas shift activity and thereby reduce CO2 selectivity and increase C5+ selectivity. Thus, not only can the properties of the Fischer-Tropsch catalyst material generally and the FT reaction parameters (e.g., temperature, GHSV, H2 / CO ratio) affect selectivity of the active catalyst, 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, through the formation of particular types of carbides in the carbided Fischer-Tropsch catalyst materials.

[0025] The present inventors have surprisingly found that by selection of carbiding conditions during the activation of iron-based FT catalysts, the selectivity of the catalysts towards producing oxygenates can be favored or suppressed. This effect is demonstrated herein on a variety of different catalysts, and thus is applicable generally to iron-based FT catalysts of a variety of elemental compositions, in both supported and bulk catalyst versions. As described herein, certain low-temperature carbiding processes provide relatively higher oxygenate selectivity. But surprisingly, if a high-temperature carbiding process is used instead, oxygenate selectivity is suppressed - as is water-gas shift activity. The present inventors have determined that the high-temperature carbiding provides a different form of carbide than does the low-temperature carbiding.

[0026] Accordingly, one aspect of the disclosure is a process for providing a carbided Fischer-Tropsch catalyst material. The process includes providing a Fischer-Tropsch catalyst material comprising iron; and 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 300 °C for a time sufficient to provide a carbided Fischer-Tropsch catalyst material having at least 50 atom% of its iron in carbided form.

[0027] 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 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 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 withoutreference 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.

[0028] As noted above, a wide variety of Fischer-Tropsch catalyst materials can be provided for use in the processes described herein. Such materials will typically include a high proportion of iron, e.g., at least 10 wt% on an elemental basis as determined by ICP. In various embodiments, the provided Fischer-Tropsch catalyst material will include 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. In various embodiments, the provided Fischer-Tropsch catalyst material will include 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. The provided catalyst material can include any of a variety of other elemental components, e.g. zinc, alkali metals, copper, silicon. The provided catalyst material can be supported (e.g., with a refractory oxide acting as a binder or substrate for iron material) or unsupported. The person of ordinary skill in the art is familiar with a wide variety of iron-based Fischer-Tropsch catalyst materials, and can select appropriate materials based on the present disclosure and the level of skill in the art.

[0029] The carbiding can be performed in any convenient manner. In some embodiments, the provided Fischer-Tropsch catalyst material is a reduced Fischer-Tropsch catalyst material, in which at least a portion of the iron of the provided Fischer-Tropsch catalyst material is in the form of metallic iron. Without intending to be bound by theory, the inventors understand that it can be helpful to reduce oxidic iron species typically present in many Fischer-Tropsch catalyst materials to metallic iron species, so that they can be more easily carbided in a subsequent treatment with a carbiding gas. But in some cases, the Fischer-Tropsch catalyst material can be stored in a form that is itself largely metallic, and so a pre-reduction step is not necessary to provide a reduced catalyst material. In various embodiments, at least 50 atom% of the iron of the reduced Fischer-Tropsch catalyst material is in the form of metallic iron, e.g., at least 70 atom%. In various embodiments, at least 80 atom% of the iron of the reduced Fischer-Tropsch catalyst material is in the form of metallic iron, e.g., at least 90 atom%. The proportion of iron in reduced form is measured by XRD, i.e. , as a proportion of iron species quantifiable by XRD.

[0030] In various embodiments, the providing of the reduced Fischer-Tropsch catalyst material includes a reduction step, in which the Fischer-Tropsch catalyst material is treated with a reducing gas stream comprising hydrogen for a time and at a temperature sufficient to provide at least a portion of the iron in a metallic state (e.g., at least 50 atom%, or some other value described herein). Upon treatment with the reducing gas stream, a portion of the iron components present in the FT catalyst as described herein react to metallic iron (Fe°).

[0031] In various embodiments, the treatment with the reducing gas stream is performed in the substantial absence of carbon monoxide and / or carbon dioxide. For example, in various embodiments, the reducing gas stream comprises no more than 1 vol% monoxide and / or carbon dioxide, 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% monoxide and / or carbon dioxide. 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. Of course in other embodiments, some monoxide and / or carbon dioxide may be present; as described in more detail below, this may cause some carbiding of the material.

[0032] 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 reducing gas stream is conducted at a temperature in the range of 300-650 °C, or 350-600 °C, or 350-550 °C, or 350-500 °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. 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 375-650 °C, or 375-600 °C, or 375-550 °C, or 375-500 °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 400-650 °C, or 400-600 °C, or 400-550 °C, or 400-500 °C.

[0033] As described above, treating the Fischer-Tropsch catalyst material with the reducing gas stream is conducted for a time sufficient to provide at least a portion of the iron of the Fischer-Tropsch catalyst material in metallic state (e.g., at least 50 atom%, or some other amount described herein). 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.

[0034] 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, providing the Fischer-Tropsch catalyst material comprises providing an oxidic Fischer-Tropsch catalyst material; in such embodiments, the treatment with the carbiding gas stream is desirably performed in the presence of hydrogen.

[0035] As described above, the carbiding is performed with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide. 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 residual oxidic iron after reduction (e.g., Fe3C>4) can cause carbon dioxide, in the presence of hydrogen, to be converted via the reverse water-gas shift reaction to carbon monoxide, which can act as the active carbiding species.

[0036] 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. 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 withthe 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.

[0037] As noted above, the present inventors have found that carbiding at high- temperature conditions can provide improved carbided Fischer-Tropsch catalyst materials. In various embodiments, treating the provided 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. For example, in various embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature of at least 325 °C, e.g., in the range of 325-650 °C, e.g., 325- 600 °C, or 325-550 °C, or 325-500 °C. In various embodiments as described herein, treating the Fischer-Tropsch catalyst material with a carbiding gas stream is conducted at a temperature of at least 350 °C, e.g., 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 of at least 375 °C, e.g., 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 of at least 400 C, e.g., in the range of 400-650 °C, e.g., 400-600 °C, or 400-550 °C, or 400-500 °C.

[0038] Moreover, even when a Fischer-Tropsch catalyst material is initially carbided under lower temperature conditions (e.g., to form £-Fe3C and r|-Fe2C as described below), 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, but is nonetheless contemplated as a way to make carbided materials with high amounts of X-FesC2. Moreover, in such high-temperature Fischer-Tropsch processes Cs+ 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). Similarly, a Fischer- Tropsch catalyst material that has previously been carbided under lower temperature conditions (e.g., to form £-Fe3C and q-Fe2C as described below) can be the provided Fischer-Tropsch catalyst material for a higher-temperature carbiding process; the present inventors note that the carbide form will convert substantially to x-Fe5C2 under such high- temperature conditions.

[0039] The person of ordinary skill in the art can, based on the present disclosure, select carbiding conditions including temperature and time to provide a desired degree of carbidingto the carbided Fischer-Tropsch catalyst material, e.g., at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material. In various embodiments, treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide at least 55 atom% of the iron of the carbided Fischer-Tropsch catalyst material in carbided form, e.g., at least 60 atom%. In various embodiments, treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide in the range of 50-95 atom% of the iron of the carbided Fischer- Tropsch catalyst material in a carbide form, e.g., in the range of 50-90%, or 50-85%, or 50- 80%. In various embodiments, treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide in the range of 55-95 atom% of the iron of the carbided Fischer-Tropsch catalyst material in a carbide form, e.g., in the range of 55-90%, or 55-85%, or 55-80%. In various embodiments, treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide in the range of 60-95 atom% of the iron of the carbided Fischer-Tropsch catalyst material in a carbide form, e.g., in the range of 60-90%, or 60-85%, or 60-80%. The amounts of iron that are in the form of oxides and carbides are determined by Mbssbauer spectroscopy, and as such are expressed as an atomic fraction of iron in the form of carbide of the total iron species visible to Mbssbauer spectroscopy.

[0040] In many cases, it will be desirable to suppress water-gas shift activity in the carbided Fischer-Tropsch catalyst material. In cases where the feed to the Fischer-Tropsch synthesis has relatively low amounts of carbon dioxide, there is often no desire for water-gas shift activity, and so oxidic carbon can be minimized. Iron oxide has high water-gas shift activity, and so it can be desirable to minimize the amount of iron oxide in the as-carbided material. Accordingly, in various embodiments, no more than 20 atom% of iron is in oxidic form, e.g., no more than 10 atom%. In various embodiments 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%. Such materials can be especially useful when 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).

[0041] However, it may be desirable in some cases for there to remain some iron oxide in the carbided Fischer-Tropsch catalyst material. Iron oxide has high water-gas shift activity, and as such may be desirable in cases where some shift activity (e.g., reverse water-gas shift activity to convert CO2 to CO in situ) may be desirable. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 5 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., at least 10 atom%, or at least 15 atom%, or at least 20 atom%. Invarious embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 5 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., at least 10 atom%, or at least 15 atom%, or at least 20 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 5-50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 5-45 atom%, or 5-40 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 10-50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 10-45 atom%, or 10-40 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 15-50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 15-45 atom%, or 15-40 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 20-50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 20-45 atom%, or 20-40 atom%.

[0042] The person of ordinary skill in the art can, based on the present disclosure, select desirable carbiding times, in conjunction with other carbiding parameters, to provide desired carbided Fischer-Tropsch catalyst materials. For example, in various embodiments, treating the provided 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.

[0043] The present inventors note that high-temperature carbiding tends to provide a carbided catalysts having carbide substantially, and even predominantly, in the form of x- Fe5C2. For example, in various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 45 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 55 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 65 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 75 atom%. In various embodiments, after treating the provided Fischer Tropschcatalyst material with the carbiding gas stream, at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 85 atom%. Without intending to be bound by theory, the present inventors surmise that it is this different carbide form in high-temperature carbided catalysts as compared to catalysts carbided at lower temperature (i.e. , e-Fe3C and r|-Fe2C forms) that is largely responsible for the significant differences in performance.

[0044] 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, wherein at least 50 atom% of the iron of the Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 45 atom%. In various embodiments, at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 55 atom%. In various embodiments, at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 65 atom%. In various embodiments, at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 75 atom%. In various embodiments, at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 85 atom%.

[0045] Carbided Fischer-Tropsch catalyst materials can in various embodiments be provided with amounts of various phases and constituents as described above with respect to processes above.

[0046] The carbided Fischer-Tropsch catalyst materials of the disclosure can be made, for example, by the high-temperature processes described herein.

[0047] Another aspect of the disclosure is a low-temperature carbiding process for iron-based Fischer-Tropsch catalyst materials. The present inventors have noted that lower temperature carbiding operations can provide catalysts that have higher selectivity for oxygenated hydrocarbons like alcohols. These can provide value in a number of situations.

[0048] Accordingly, another aspect of the disclosure is a process for providing a carbided Fischer-Tropsch catalyst material. The process includes providing a Fischer- Tropsch catalyst material comprising iron; and 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 in the range of 160-300 °C for time sufficient to provide a carbided Fischer-Tropsch catalyst material having at least 50 atom% of its iron in carbided form.

[0049] The provided catalyst material can generally be as described above with respect to the high-temperature carbiding, e.g., pre-reduced or otherwise in a reduced state, and of a variety of compositions and iron contents. As noted above, when the carbiding gas stream includes hydrogen, pre-reduction may not be necessary as the catalyst can be reduced as part of the carbiding operation.

[0050] As described above, the carbiding is performed with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide. 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, as described above with respect to the high-temperature carbiding.

[0051] As described above with respect to the high-temperature carbiding process, 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 in the range of 0.5:1 to 1.5:1. In other embodiments the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of at least 1.5:1 (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). 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.

[0052] As noted above, the present inventors have found that carbiding at low- temperature conditions can provide catalysts with different performance than carbiding at high temperatures, e.g., with respect to product selectivity. In various embodiments, treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is conducted at a temperature in the in the range of 160-280 °C, e.g., 160-250 °C, or 160-230 °C or 160-220 °C, or 160-210 °C, or 160-200 °C. In various embodiments, treating the reduced catalyst material with the carbiding gas stream is conducted at a temperature in the range of 170-300 °C, e.g., 170-280 °C, or 170-250 °C, or 170-230 °C or 170-220 °C, or 170-210 °C, or 170- 200 °C. In various embodiments, treating the reduced catalyst material with the carbiding gas stream is conducted at a temperature in the range of 180-300 °C, e.g., 180-280 °C, or 180-250 °C, or 180-230 °C or 180-220 °C, or 180-210 °C, or 180-200 °C.

[0053] The person of ordinary skill in the art can, based on the present disclosure, select carbiding conditions including temperature and time to provide a desired degree of carbiding to the carbided Fischer-Tropsch catalyst material, e.g., at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material, or any other amount as described above with respect to the high-temperature process. The amount of oxidic carbon can likewise be as described above.

[0054] The person of ordinary skill in the art can, based on the present disclosure, select desirable carbiding times, in conjunction with other carbiding parameters, to provide desired carbided Fischer-Tropsch catalyst materials. For example, in various embodiments, treating the provided 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.

[0055] The present inventors note that lower-temperature carbiding tends to provide a carbided catalysts having carbide substantially, and even predominantly, in the form of one or more of e-Fe3C and r|-Fe3C. For example, in various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 45 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 55 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 60 atom% of the iron of the carbided Fischer- Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and r|-Fe3C, e.g., at least 65 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 75 atom%. In various embodiments, after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 85 atom%. Without intending to be bound by theory, the present inventors surmise that it is this different carbide form in low-temperature carbided catalysts as compared to catalysts carbided at lower temperature (i.e., x-Fe5C2) that is largely responsible for the significant differences in performance.

[0056] 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, wherein at least 50 atom% of the iron of the Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and r|-Fe3C, e.g., at least 45 atom%. In various embodiments, at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 55 atom%. In various embodiments, at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e- Fe3C and q-Fe3C, e.g., at least 65 atom%. In various embodiments, at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 75 atom%. In various embodiments, at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 85 atom%.

[0057] Carbided Fischer-Tropsch catalyst materials can in various embodiments be provided with amounts of various oxide phases and constituents as described above with respect to the high-temperature processes above.

[0058] The carbided Fischer-Tropsch catalyst materials of the disclosure can be made, for example, by the low-temperature processes described herein.

[0059] Another aspect of the present disclosure provides a process for performing a Fischer-Tropsch process. The process includes providing a 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. The processes can advantageously be performed with any of the carbided catalysts materials described herein; the product distribution will, of course, depend on the particular carbided catalyst. As the person of ordinary skill in the art will appreciate, carbiding and, if used, reduction, can be performed in a Fischer-Tropsch reactor by adjusting temperature, pressure and inlet composition.

[0060] 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 a carbided Fischer-Tropsch catalyst material 123,here, in a reaction zone (e.g., a reactor 120). This provides a product stream 122, which includes C5+ hydrocarbons.

[0061] 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, with or without a pre-reduction step. 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, 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. However, operating the Fischer-Tropsch process at such high temperatures may provide a less desirable product distribution, in that it tends to form more of the less desirable C1-C4 hydrocarbons. Accordingly, when C5+ hydrocarbons are a desired product from a carbided Fischer-Tropsch catalyst having a high degree of x-Fe5C2,, it may be desirable to perform a separate high-temperature carbiding, then run the Fischer-Tropsch process at lower temperature (e.g., less than 300 °C).

[0062] 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 CO2 in 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 H2 to be provided to the feed stream.

[0063] 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.

[0064] 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 H2 of 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.

[0065] 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 a renewable source, e.g., to provide so-called “green hydrogen.” However, the present inventors have noted that electricity can be generated as part of the claimed process, e.g., using heat exchange from the 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.

[0066] 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. 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.

[0067] 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%.

[0068] To reduce WGS activity, it can be desirable to have CO2 present in the feed stream; as the water-gas shift is generally an equilibrium process, the presence of CO2 helps to disfavor the 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 CO2 to 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 CO2 to CO in the feed stream is no more than 0.5, e.g., no more than 0.3.

[0069] Similarly, to reduce WGS 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.

[0070] 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.

[0071] 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. [

[0072] In various embodiments, and as described above, the reduced Fischer-Tropsch catalyst material can be carbided by contact with CO and / or CO2. Here, too, the feed stream can be adjusted to provide a desired amount of CO and / or CO2, 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 is adjusted 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.

[0073] As described above, the process includes contacting at a temperature and at a pressure the carbided Fischer-Tropsch catalyst material 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 150-250 °C, or 150-200 °C, or 200-400 °C, or 200-350 °C, or 200- 300°C, or 200-250 °C, or 250-400 °C, or 250-350 °C, or 250-300 °C, or 300-400 °C. In some particular embodiments, the temperature is in the range of 200-350 °C. In other embodiments, the temperature is in the range of 180-280 °C, e.g., 180-260 °C, or 180-240 °C, or 180-220 °C, or 200-280 °C, or 200-260 °C, or 200-240 °C.

[0074] 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.

[0075] 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 IT1. 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 IT1, or 1,000 to 500,000 IT1, or 1,000 to 100,000 IT1, or 5,000 to 1,200,000 IT1, or 5,000 to 500,000 IT1, or 5,000 to 100,000 IT1, or 10,000 to 1,200,000 IT1, or 10, 000 to 500,000 IT1, or 10, 000 to 100,000 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 IT1, or2,000 to 50,000 IT1, or 5,000 to 50,000 tr1, or 10, 000 to 50,000, or 1 ,000 to 40,000 tr1, or 2,000 to 40,000 IT1, or 5,000 to 40,000 tr1, or 10, 000 to 40,000 tr1, or 1 ,000 to 30,000 tr1, or 2,000 to 30,000 IT1, or 5,000 to 30,000 tr1, or 10,000 to 30,000 tr1.

[0076] 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%.

[0077] In some embodiments (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of x-FesC2 and / or is made by high-temperature carbiding), 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%. In some embodiments (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of x-Fe5C2 and / or is made by high-temperature carbiding), 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%. In some embodiments (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of x-Fe5C2 and / or is made by high-temperature carbiding), 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 7%, e.g., no more than 6%. In some embodiments (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of x-FesC2 and / or is made by high-temperature carbiding), 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 5%, e.g., no more than 4%. For example, in various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 1-30%, e.g., 1-25%, or 1-20%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 1-15%, e.g., 1-10%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 1-5%, e.g., 1-4%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 2- 30%, e.g., 2-25%, or 2-20%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 2-15%, e.g., 2-10%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 2-5%, e.g., 2-4%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 3- 30%, e.g., 3-25%, or 3-20%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 3-15%, e.g., 3-10%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 3-5%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 4-30%, e.g., 4- 25%, or 4-20%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 4-15%, e.g., 4-10%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 4-8%, e.g., 4-6%.

[0078] In some embodiments, (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of one or more of e-FesC and q-FesC and / or is made by low- temperature carbiding), contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity of at least 7%, e.g., at least 9%. In some embodiments, (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of one or more of e-FesC and q-FesC and / or is made by low- temperature carbiding), contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity of at least 11 %, e.g., at least 13%. In some embodiments, (e.g., when the carbided Fischer-Tropsch catalyst material has a high proportion of one or more of e-FesC and q-FesC and / or is madeby low-temperature carbiding), contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity of at least 15%, e.g., at least 17%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 7-30%, e.g., 9-30%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 11-30%, e.g., 13-30%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 15- 30%, e.g., 17-30%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 7-27%, e.g., 9-27%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 11-27%, e.g., 13-27%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 15-27%, e.g., 17-27%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 7-24%, e.g., 9-24%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 11-24%, e.g., 13-24%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 15-24%, e.g., 17-24%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 7- 22%, e.g., 9-22%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 11-22%, e.g., 13-22%. In various embodiments, contacting of the Fischer- Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 15-22%, e.g., 17-22%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 7-20%, e.g., 9-20%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 11- 20%, e.g., 13-20%. In various embodiments, contacting of the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 15-20%, e.g., 17-20%.

[0079] 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 H2 can be present, e.g., unreacted from the feed stream. CO2 or other inerts as described herein can also be present. Such components of the product stream can be separated and / or recycled in various manners.

[0080] 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 water-containing stream 334.

[0081] 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.

[0082] There are other uses for the light hydrocarbon stream. For example, in some embodiments, the process further comprises oxidizing at least a portion of the light hydrocarbon stream to provide a CO- and / or CO2-containing partial oxidation (pOX) stream, and including at least a portion of the pOX stream in 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 CO2 containing pOX stream, and including at least a portion of the pOX stream 454 stream in the feed stream 421.

[0083] Moreover, the light hydrocarbon stream can be burned to provide heat energy, which can be used to heat various process streams, or to generate electricity. Accordingly, in various embodiments, the process includes burning at least a portion of the light hydrocarbon stream to provide energy, e.g., heat energy or electrical energy. For example, in the process 400 of FIG. 4, a portion of light hydrocarbon stream 450 is burned in a power generation zone (here, in an electrical generator 470), to generate electricity stream 472. In various embodiments, the heat energy may be used to provide the needed heat duty for the 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.

[0084] 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.

[0085] 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).

[0086] 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 H2 of 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.

[0087] 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.

[0088] In many cases, both CO and H2of the second product stream will be recycled.

[0089] 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).

[0090] 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.

[0091] 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.

[0092] The present inventors have noted that the same base Fischer-Tropsch catalyst material can provide different product selectivities, depending on the carbiding method and / or the particular type of carbide present. Moreover, they have noted that a change ofselectivity can be effected in situ in a reactor, e.g., without unloading the Fischer-Tropsch catalyst.

[0093] Accordingly, another aspect of the disclosure is a process for performing a sequence of Fischer Tropsch processes comprising: performing a first Fischer-Tropsch process as described herein, using a carbided Fischer-Tropsch catalyst material having a high amount of iron carbide in the form of £-Fe3C and / or q-Fe3C, or made by a low-temperature carbiding process as described herein; then performing a second Fischer-Tropsch process as described herein, using a carbided Fischer-Tropsch catalyst material having a high amount of iron carbide in the form of x-Fe5C2, or made by a high-temperature carbiding process as described herein, wherein the carbided Fischer-Tropsch catalyst material used in the second Fischer- Tropsch process is provided by carbiding the Fischer-Tropsch catalyst material used in the first Fischer-Tropsch process to provide the carbided Fischer-Tropsch catalyst material used in the second Fischer-Tropsch catalyst process.This can optionally include regenerating the Fischer-Tropsch catalyst material used in the first Fischer-Tropsch process to a substantially oxidic form, then carbiding that substantially oxidic Fischer-Tropsch catalyst material. But the inventors note that a Fischer-Tropsch catalyst material Fischer-Tropsch catalyst material having a high amount of iron carbide in the form of e-Fe3C and / or q-Fe3C can be converted to one having a high amount of iron carbide in the form of x-Fe5C2, through high-temperature treatment (e.g., at least 300 °C), optionally in the form of a carbiding gas stream as described above.

[0094] Similarly, another aspect of the disclosure provides a process for performing a sequence of Fischer Tropsch processes comprising: performing a second Fischer-Tropsch process as described herein, using a carbided Fischer-Tropsch catalyst material having a high amount of iron carbide in the form of x-Fe5C2, or made by a high-temperature carbiding process as described herein; then performing a first Fischer-Tropsch process as described herein, using a carbided Fischer-Tropsch catalyst material having a high amount of iron carbide in the form of e-Fe3C and / or q-Fe3C, or made by a low-temperature carbiding process as described herein; wherein the carbided Fischer-Tropsch catalyst material used in the second Fischer- Tropsch process is provided by regenerating the Fischer-Tropsch catalyst material used in the first Fischer-Tropsch process to a substantially oxidic form,then carbiding the resulting substantially oxidic Fischer-Tropsch catalyst material to provide the carbided Fischer-Tropsch catalyst material used in the second Fischer-Tropsch catalyst process.

[0095] Notably, by re-carbiding the Fischer-Tropsch catalyst material, a different selectivity (e.g., for oxygenates vs. olefins) can be provided. Accordingly, operators can select different product mixtures for production at different times.

[0096] The person of ordinary skill in the art is familiar with regeneration processes for catalyst materials. These typically require oxidation at high temperature to burn away carbon and to convert the catalytic metals, here, iron, to substantially oxidic form. In various embodiments, regenerating the Fischer-Tropsch catalyst material used in the first Fischer- Tropsch process to a substantially oxidic form is performed by treatment with an oxidizing gas (e.g., comprising oxygen) at a temperature in excess of 400 °C.

[0097] In various embodiments, at least 50 atom% of the iron of the substantially oxidic Fischer-Tropsch catalyst material is in an oxidic form, e.g., at least 70 atom%, or at least 90 atom%, as determined by Mbssbauer spectroscopy.

[0098] In various embodiments, the sequence is performed without removing the Fischer-Tropsch catalyst material from a reactor in which the first and second Fischer- Tropsch processes are performed.

[0099] 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

[0100] 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.Example 1 - Preparation of FeSiCuK catalyst material

[0101] This example demonstrates the preparation and characterization of an unsupported iron-oxide catalyst material (pre-catalyst) with the chemical composition (on an oxide basis) 50Fe2O3 / 4.4SiC>2 / 2.6CuO / 0.5K2O. A typical procedure is as follows:1) Weigh 484.8 (1.20 mol) of Fe(NO3)3'9H2O and 7.26 g (0.0312 mol) of CU(NOS)2-2.5H2O was first dissolved in 1200 g of deionized water under vigorous stirring to obtain solution A.2) Weigh 457.8 g (2.75 mol) of K2CO3 and dissolved in 1200 g of deionized water in a separate container under vigorous stirring to obtain solution B.3) Weigh 1200 g of DI water into a 5-liter 5-neck round bottom flask equipped with a mechanical stirrer, a heating mantle / temperature control system and a condenser.4) Increase the temperature of the water in the round bottom flask to 80 °C, then adjust the pH of the water to 9 with the K2CO3 solution prepared above.5) Simultaneously add the solutions A and B at the same rate while monitoring the pH of the precipitation medium; adjust by changing the addition rate of solution B.6) Rinse all the containers with 400 g of DI water and combine the solution into to round bottom flask.7) To the above slurry add 11.00 g (0.0528 mol) tetraethyl orthosilicate under vigorous stirring.8) After allowing the resultant solid to age at 80 °C for 2h, turn off the heater and let the system to cool down to a temperature below 40 °C.9) Transfer the slurry into six 1000 mL centrifuge bottles; adjust the quantify in each bottle to 1000 g with DI water.10) Separate the solids using a centrifuge at 9000 rpm for 10 min.11) Re-slurry the solids in 4 L DI water and repeat the separation and washing for 4 more times.12) Recover the solid in the final round through vacuum filtration, then dry the solid in a hood overnight followed by drying in an oven at 110 °C overnight.13) Pulverize the solid using a mortar grinder, then load the powder into a Rotavapor flask loaded with 0.83 g of K2CO3 dissolved into 150 g of DI water.14) Let the slurry to rotate at 60 °C for 60 min.15) Remove the water at 60 °C under 125 mm Hg vacuum.16) Recover the solid and dry in an oven at 110 °C overnight, then calcine the solid in air flow at 300 °C for 4 h, via a ramp of 2 °C / min to obtain the oxidic catalyst material.

[0102] Properties of the oxidic catalyst material were measured using nitrogen adsorption-desorption method at 77.15 K; the sample was degassed under 10'6mm Hg vacuum at 300 °C overnight. The results are as follows:

[0103] BET area: 203 m2 / g

[0104] Pore volume: 0.24 cm3 / g

[0105] FIG. 5 provides the XRD pattern of this sample, in which a-Fe2O3 was the only crystalline phase discerned, which is indicated by the vertical lines. Other chemical compositions in this sample are highly dispersed or present in amorphous form that were not discernable by XRD.Example 2 - Carbiding FeSiCuK catalyst material to form x-FesCa

[0106] This example demonstrates the conversion of a Fischer-Tropsch catalyst material, which has a composition of 50.00Fe203 / 3.91Si02 / 2.58CuO / 3.85K20 into a carbided form. In this experiment, a small amount (about 70 mg) of the sample was loaded into a high-pressure Mdssbauer in-situ cell equipped with high-pressure beryllium windows. Transmission57Fe Mdssbauer spectra were collected at 120 or 4.2 K with a sinusoidal velocity spectrometer using a57Co(Rh) source. Velocity calibration was performed using an a-Fe foil at room temperature. The source and the absorbing samples were maintained at the same temperature during the measurements. The high-pressure beryllium windows used in the cell in this study contained -0.08% Fe impurity, the spectral contribution of which was fitted and removed from the final spectra.

[0107] In the first step of the experiment, the Fischer-Tropsch catalyst material is dried under N2flow at 300 °C. The dried catalyst material was then reduced using 5% H2in N2at 400 °C for 4h, via a heating ramp of 0.5 °C / min. The reduced sample was then converted into x-FesC2 by carbiding using 20% CO in H2 at 350 °C. FIG. 6 depicts the in-situ Mdssbauer spectra of the sample collected at 4 different time points at 120 K: after drying, after reduction, and after carbiding for 2 hours and 4 hours. In the Mdssbauer spectra, there is one major trace from each of the samples, as well as additional traces attributed to each of the iron species that are present in different coordination environments. The Mdssbauer spectrum taken after reduction of the Fischer-Tropsch catalyst material (i.e. , FIG. 7B) shows a larger trace that indicates the spectrum of the sample overlaid with standard spectrum of a-Fe. Close to the baseline, there is a separate trace indicating the difference between the actual measured trace and the standard spectrum of a-Fe; this difference trace is consistent with the presence of a minor amount of ferrihydrite-like species. The Mdssbauer spectra taken during the carbiding of the Fischer-Tropsch catalyst material (i.e., FIG.s 7C and 7D) show a tallest envelope trace indicating the spectrum of the sample, whereas the other traces indicate the spectrum in different coordination environments in the x-Fe5C2structure. Each Mdssbauer spectrum was analyzed using Mosswinn 4.0, and the resulting spectroscopic parameters and phase quantification of the iron species are summarized in Table 1.

[0108] Table 1.

[0109] Based on the above results, substantially all of the iron in the Fischer-Tropsch catalyst material is in its oxidic form (i.e., Fe3+or a-Fe2O3) after drying. After reduction, 97% of the iron in the Fischer-Tropsch catalyst material is converted into a-Fe (i.e., Fe°). The in situ Mdssbauer spectrum shows that all of the iron, including unreduced Fe3+, is further converted into substantially phase-pure x-Fe5C2during the carburization process.Example 3 - Carbiding FeSiCuK catalyst material to form £-Fe2C and q-Fe2C

[0110] The same catalyst material prepared for the high temperature carbiding process in Example 2 is used in a low temperature carbiding process to prepare a catalyst wherein the iron is primarily in its e-Fe3C and q-Fe2C forms. In this experiment, a small amount (about 70 mg) of the sample was loaded into a high-pressure Mdssbauer in-situ cell equipped with high-pressure beryllium windows. Transmission57Fe Mdssbauer spectra were collected according to the Mdssbauer parameters described in Example 2. In the first step of the experiment, the Fischer-Tropsch catalyst material is dried under N2flow at 300 °C. The dried catalyst material was then reduced using 5% H2in N2at 400 °C for 4h, via a heating ramp of 0.5 °C / min. The reduced sample was then converted into e-Fe3C and q- Fe2C by carbiding using 33% CO in H2at 180 °C. FIG. 7 depicts the in-situ Mdssbauer spectra of the sample collected at 4 different time points at 120 K: after reduction and after carbiding for 2 hours, 4 hours, and 24 hours.

[0111] In the Mdssbauer spectra, there is one major trace from each of the samples, as well as additional traces attributed to each of the iron species that are present in differentcoordination environments. The Mdssbauer spectrum taken after reduction of the Fischer- Tropsch catalyst material shows a larger trace that indicates the spectrum of the sample overlaid with standard spectrum of a-Fe. Close to the baseline, there is a separate trace indicating the difference between the actual measured trace and the standard spectrum of a- Fe; this difference trace is consistent with the presence of a minor amount of ferrihydrite-like species. The Mdssbauer spectrum taken after carbiding the Fischer-Tropsch catalyst material for 24 hours shows a trace of the largest envelope indicating the spectrum of the sample, along with two relatively large sub-traces indicating spectra of £-Fe2C and r|-Fe2C, as well as a minor trace along the baseline indicating the difference of the profile fitting, the difference trace consistent with the spectrum of a-Fe. Each Mdssbauer spectrum was analyzed using Mosswinn 4.0, and the resulting spectroscopic parameters and phase quantification of the iron species are summarized in Table 2.

[0112] Table 2.

[0113] Similar to the experiment described in Example 2, 97% of the iron in the Fischer- Tropsch catalyst material is reduced to Fe° after drying and reducing the Fischer-Tropsch catalyst material. After 2 hours of the low temperature carbiding process, around 45% of the iron is converted into iron carbide, leaving 55% of the iron still as metallic iron. This is in contrast to the high temperature carbiding process, wherein all of the iron is carbided at the end of 2 hours. The iron carbide content gradually increases with low temperature carbiding, wherein 97% of the iron is carbided in the form of e-Fe3C and r|-Fe2C at the end of 24 hours. The ratio of r|-Fe2C: e-Fe3C increases over time as well, shedding insight on the metastability of these iron carbide polymorphs. Examples 2 and 3 highlight the ability to selectively form different iron carbide species via different carbiding procedures.Example 4

[0114] A series of experiments were performed to study the effect of carbiding conditions of Fischer-Tropsch catalyst materials on catalyst performance. The catalyst carbiding and Fischer-Tropsch processes described in this Example were carried out in a 4- fold parallel fixed bed reactor unit, wherein each reactor tube has an internal diameter of 6.5 mm and independent temperature and gas feed flow control. The reactor unit has two product knockout pots, first a hot pot at 180 °C for collecting high boiling waxes and a cold pot at 12 °C for collecting water and light organics. The Fischer-Tropsch processes were monitored by analyzing the 4 feed composition inlets and 4 product exit streams after knockout pots using gas chromatography.

[0115] Catalyst materials were dried using inert gas, then a H2reduction was performed under a flow of 50% H2in inert gas at 400 °C for 16 hours to substantially reduce oxidic iron to metallic iron. Following the reduction, carbiding was omitted; carbiding was performed following a low-temperature method, or carbiding was performed using a high temperature method, as described in the following.

[0116] No dedicated carbiding step: After reduction, the Fischer-Tropsch catalyst material was cooled to <130 °C before switching to syngas (H2 / CO ratio = 1.8) and ramping the temperature and pressure to Fischer-Tropsch reaction conditions (>200 °C, 33 bar).

[0117] Dedicated low-temperature carbiding step: At 180 °C, the reduced catalyst was contacted with a syngas containing a H2 / CO ratio of 1.8 for 24 hours.

[0118] Dedicated high-temperature carbiding step: Three versions of a high- temperature carbiding step were assessed: version A: carbiding was performed at 350 °C with syngas containing a H2 / CO = 1.0 for 10 hours• version B: carbiding was performed at 400 °C with syngas containing a H2 / CO = 1.0 for 6 hours• version C: carbiding was performed at 400 °C with syngas containing a H2 / CO = 33 for 6 hours

[0119] While these H2 / CO ratios were selected for this study, it will be understood that a variety of ratios can be used, and that preferred ratios may depend on temperature and catalyst composition. In this study, a H2 / CO ratio of 1.0 was found to work well at 350 °C but higher H2 / CO ratios were preferred at higher temperatures (e.g., 400 °C).

[0120] In cases where there was a separate carbiding step, the catalyst was cooled to <150 °C. Then the gas composition was switched to syngas and the system was pressurized to FT reaction pressure (30 bar), held for 1 h, and then ramped to FT reaction temperature at 2 °C / min.

[0121] A variety of catalysts were evaluated, including supported iron catalyst materials, bulk iron materials like iron ores, and catalysts synthesized by coprecipitation. Accordingly, the tested materials cover a wide range of Fe-content, promoter levels, pore structure and surface areas, etc.

[0122] Table 3 compares the concentration in wt% of alcohols collected in the water phase from a FT test in which the same bulk iron / zinc-based catalyst (i.e., Fe:Zn 1.1 :1 , no alkali promoter) was used in four parallel reactors. Around 250 mg of the Fe / Zn-based catalyst material was diluted in 500 mg SiC and placed in each of the four separate reactor tubes. Each of the reactors was subjected to a different carbiding procedure. Following the catalyst carbiding, all four reactors were subjected to 14 days on stream under the following FT reaction conditions: 200-250 °C; H2:CO = 1.8:1 to 2.2:1 ; 15-50% inerts; GHSV = 5000- 8000 IT1.Table 3. Oxygenates detected in aqueous phase of the FT product stream when applying different carbiding methods to a Fe-Zn based bulk catalyst.

[0123] The use of high-temperature carbiding conditions resulted in significantly less oxygenates in the FT product -- only about a third of the amount of oxygenates present when the FT catalyst material was allowed to carbide in situ in the FT reaction conditions.

[0124] Table 4 provides the product distribution in the organic phase of the FT product stream, which was collected in cold pots as a separate phase from the aqueous phase.Table 4. Relative content of paraffins, olefins, and alcohols in the liquid hydrocarbon phase.

[0125] The data here demonstrate that the high-temperature carbiding methods provided significantly more olefin and significantly less oxygenate than did the methods in which carbiding was achieved in situ in the FT reaction conditions. This resulted in a much higher paraffins / olefins (P / O) ratio of 1.6 in the in-situ method, as compared to a P / O ratio of -1 obtained in the hydrocarbon phase when using the high-temperature carbiding methods.Example 6 - Carbiding supported catalyst materials containing Mn and K promoters

[0126] Five different supported catalyst materials were prepared for carbiding and subsequent Fischer-Tropsch synthesis. The five different supported catalysts, containing -30% Fe, <20% Mn, and <0.5% K and using TiC>2 or MnTiOs as the support, were prepared according to the following general procedure for incipient wetness impregnation: Fe(NOs)3 and KNO3 were dissolved in 14 mL water at 45 °C with the aid of ultrasound treatment. An oxide support (i.e. , TiC>2 or MnTiOs) was placed in a large crucible, and the metallic salt solution was added dropwise with mechanical mixing of the oxide until all of the metallic solution has been added. The mixture is further mixed for at least 10 minutes until a wet paste is formed. The paste was dried in a fume cupboard for 3 hours with occasional mechanical agitation to break up agglomerates and prevent adhering to the surface of the crucible. The material is dried in a muffle furnace, ramping at 2 °C / min to 120 °C, and then holding at 120 °C for 5 hours. After drying, the material was broken up to provide a powder. Additional rounds of incipient wetness impregnation as described above can be carried outon the parent material to provide additional Fe (using Fe(NOs)3), Mn (using Mn(OAc)2), and / or K (using KNO3). The five different support catalysts synthesized for this Example have the following compositions:Supported Catalyst 1: 30 wt% Fe, 0.15 wt% K, TiO2supportSupported Catalyst 2: 30 wt% Fe, 0.15 wt% K, 10 wt% Mn, TiO2supportSupported Catalyst 3: 30 wt% Fe, 0.15 wt% K, 20 wt% Mn, TiO2supportSupported Catalyst 4: 30 wt% Fe, 0.5 wt% K, TiO2supportSupported Catalyst 5: 30 wt% Fe, 0.5 wt% K, MnTiOs support

[0127] For these five supported catalyst materials, the effect of low-temperature carbiding (conditions described above) was compared with the effect of high carbiding (using option C as described above). Tests were carried out in a in a 16-fold parallel fixed bed reactor unit, wherein two blocks of 8 tubes, each 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 for collecting high boiling waxes and cold knockout pots at 10 °C to collect water and light organics. The Fischer-Tropsch processes were monitored by analyzing with online GC analysis of light gases and hydrocarbons covering the range of C1- C10. Around 250 mg of each of the five supported catalyst materials were diluted in 500 mg of SiC and placed in separate reactor tubes. After activating the Fischer-Tropsch catalyst materials with carbiding conditions mentioned above, all reactors were subjected to the following Fischer-Tropsch reaction conditions: H2 / CO = 1, syngas GHSV = 1800, T = 245 °C and P = 30 bar. Table 5 provides results:

[0128] Table 5. Performance for K and Mn promoted Fe / TiO2or Fe / TiOs catalysts.

[0129] As indicated in the last column of Table 5 a consistently higher selectivity towards C2-C8 oxygenates resulted when applying the low temperature carbiding method compared to applying the high temperature method. The activity resulting from the two different carbiding methods was similar (~ ±10% relative change in conversion). It is noteworthy that the Olefins / Paraffins ratio, e.g. in the C2-C4 was notably higher for the high-temperature carbiding method. For the different catalysts, this O / P ratio in the C2-C4 range was 15-34% higher when activating the catalysts with the high-temperature carbiding method compared to the low-temperature carbiding method.

[0130] Similar effects were observed for FT reactions conducted under reaction conditions (higher H2 / CO = 1.8, GHSV = 1500 IT1, T = 245 °C and p = 30 bar), as shown in Table 6. Here, for the different catalysts the O / P ratio in the C2-C4 range was 12-72% higher when activating the catalysts with the high-temperature carbiding method compared to activating with the low-temperature carbiding method.

[0131] Table 6. Performance under different reaction conditions.Example 7 - Carbiding supported catalyst materials containing Cu and K promoters

[0132] In this Example, the Fischer-Tropsch catalyst material tested was a bulk iron catalyst with silicon and different levels of copper and potassium as promoters. These Fischer-Tropsch catalyst materials generally comprise at least 75 wt% iron; silicon, in a molar ratio of silicon to iron in the range of 0.01-0.12; copper, in a molar ratio of copper to iron in the range up to 0.12; and potassium, in a molar ratio of alkali metal to iron in the range of 0.003-0.10. Reactions were performed under three different sets of reaction conditions, as indicated in Tables 7-9 below.Table 7. Performance for four different bulk FeSiCuK catalysts at H2 / CO = 1.8, syngas GHSV = 1500 IT1, T = 230 °C and p = 30 bar. Comparison of high temperature vs. low temperature carbiding.Table 8. Performance for four different bulk FeSiCuK catalysts at H2 / CO = 1.8, syngas GHSV = 1500, T = 245 °C and p = 30 bar. Comparison of high temperature vs. low temperature carbiding.Table 9. Performance for four different bulk FeSiCuK catalysts at H2 / CO = 1.0, syngas GHSV = 1700 IT1, T = 245 °C and p = 30 bar. Comparison of high temperature vs. low temperature carbiding.

[0133] For the different catalysts the O / P ratio in the C2-C4 range was always higher when activating the catalysts with the high T carbiding method compared to activating with the low T carbiding method, under all reaction conditions, as shown in Table 10:Table 10: Comparison of O / P ratios under different reaction conditions.Example 8

[0134] Tables 11 and 12 expand on the results demonstrated in Example C, demonstrating a similar effect for two further bulk FeSiCuK catalysts and two red mud-based catalysts. As the person of ordinary skill in the art will appreciate, red mud, also known as bauxite residue, is an industrial waste generated during the processing of bauxite into alumina using the Bayer process. It is composed of various oxide compounds, including the iron oxides which give its red color, as well as around 2.4 wt% sodium. One of the catalysts was red mud as received, while the other was promoted by the addition of 0.2 wt% potassium.Table 11. Performance for two different bulk FeSiCuK catalysts and two red mud catalysts at H2 / CO = 1.8, syngas GHSV = 2500 IT1, T = 230 °C and p = 30 bar. Comparison of high temperature vs. low temperature carbiding.Table 12. Performance for two different bulk FeSiCuK catalysts and two red mud catalysts at H2 / CO = 1.8, syngas GHSV = 2500 IT1, T = 245 °C and p = 30 bar. Comparison of high temperature vs. low temperature carbiding.

[0135] For the different catalysts the O / P ratio in the C2-C4 range was always higher when activating the catalysts with the high T carbiding method compared to activating with the low T carbiding method, under all reaction conditions, as shown in Table 13:

[0136] Table 13: Comparison of O / P ratios under different reaction conditions.

[0137] Additional aspects of the disclosure are provided by the following enumerated embodiments, which may be combined in any number and in any combination that is not logically or technically inconsistent.Embodiment 1. A process for providing a carbided Fischer-Tropsch catalyst material, the process comprising: providing a Fischer-Tropsch catalyst material comprising iron; treating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide (e.g., carbon monoxide), at atemperature of at least 300 °C for a time sufficient to provide a carbided Fischer- Tropsch catalyst material having at least 50 atom% of its iron in carbided form.Embodiment 2. The process according to embodiment 1 , wherein the provided 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 process according to embodiment 1 , wherein the provided 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 process of any of embodiments 1-3, wherein the provided Fischer-Tropsch catalyst material is a reduced Fischer-Tropsch catalyst material in which at least a portion of the iron of the provided Fischer-Tropsch catalyst material is in the form of metallic iron.Embodiment 5. The process of embodiment 4, wherein at least 50 atom% of the iron of the reduced Fischer-Tropsch catalyst material is in the form of metallic iron, e.g., at least 70 atom%.Embodiment 6. The process of embodiment 4, wherein at least 80 atom% of the iron of the reduced Fischer-Tropsch catalyst material is in the form of metallic iron, e.g., at least 90 atom%.Embodiment 7. The process of any of embodiments 4-6, wherein providing the reduced Fischer-Tropsch catalyst material contacting an oxidic Fischer-Tropsch catalyst material comprising iron with a reducing gas stream comprising hydrogen for a time and at a temperature sufficient to provide at least a portion of the iron in a metallic state.Embodiment 8. The process of embodiment 7, wherein the contacting with the reducing gas stream is performed in the substantial absence of carbon monoxide and / or carbon dioxide.Embodiment 9. The process of embodiment 7 or embodiment 8, wherein the reducing gas stream further comprises an inert gas (e.g., nitrogen).Embodiment 10. The process of embodiment 9, wherein the hydrogen and inert gas are present in the reducing gas stream in a ratio of at least 1 :1.Embodiment 11. The process of any of embodiments 7-10, wherein treating the Fischer-Tropsch catalyst material with a 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 12. The process of any of embodiments 7-10, wherein treating the Fischer-Tropsch catalyst material with a 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 13. The process of any of embodiments 7-10, wherein treating the Fischer-Tropsch catalyst material with a 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 14. The process of any of embodiments 7-10, wherein treating the Fischer-Tropsch catalyst material with reducing gas stream is conducted at a temperature in the range of 375-650 °C (e.g., in the range of 375-600 °C, or 375-550 °C, or 375-500 °C).Embodiment 15. The process of any of embodiments 7-10, wherein treating the Fischer-Tropsch catalyst material with reducing gas stream is conducted at a temperature in the range of 400-650 °C (e.g., in the range of 400-600 °C, or 400-550 °C, or 400-500 °C).Embodiment 16. The process of any of embodiments 7-15, wherein treating the Fischer-Tropsch catalyst material with reducing gas stream is conducted for a time of at least 12 hours, e.g., at least 14 hours.Embodiment 17. The process of any of embodiments 7-15, wherein treating the Fischer-Tropsch catalyst material with 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 18. The process of any of embodiments 1-17, wherein providing the Fischer-Tropsch catalyst material comprises providing an oxidic Fischer-Tropsch catalyst material, and wherein the treatment with the carbiding gas stream is performed in the presence of hydrogen.Embodiment 19. The process of embodiment 18, wherein the carbiding gas stream comprises hydrogen and carbon monoxide in a molar ratio 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 20. The process of embodiment 18, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio in the range 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 21. The process of embodiment 18, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio in the range 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.Embodiment 22. The process of any of embodiments 1-21 , wherein treating the provided 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 23. The process of any of embodiments 1-21 , wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is conducted at a temperature of at least 325 °C, e.g., in the range of 325-650 °C, e.g., 325-600 °C, or 325- 550 °C, or 325-500 °CEmbodiment 24. The process of any of embodiments 1-21 , wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is conducted at a temperature of at least 350 °C, e.g., in the range of 300-650 °C, e.g., 350-600 °C, or 350- 550 °C or 350-500 °C.Embodiment 25. The process of any of embodiments 1-21 , wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is conducted at a temperature of at least 375 °C, e.g., in the range of 375-650 °C, e.g., 375-600 °C, or 375- 550 °C, or 375-500 °CEmbodiment 26. The process of any of embodiments 1-21, wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is conducted at atemperature of at least 400 °C, e.g., in the range of 400-650 °C, e.g., 400-600 °C, or 400- 550 °C, or 400-500 °CEmbodiment 27. The process of any of embodiments 1-26, wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide at least 55 atom% of the iron of the carbided Fischer-Tropsch catalyst material in carbided form, e.g., at least 60 atom%.Embodiment 28. The process of any of embodiments 1-26, wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide in the range of 50-95 atom% of the iron of the carbided Fischer- Tropsch catalyst material in a carbide form, e.g., in the range of 50-90%, or 50-85%, or 50- 80%.Embodiment 29. The process of any of embodiments 1-26, wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide in the range of 55-95 atom% of the iron of the carbided Fischer- Tropsch catalyst material in a carbide form, e.g., in the range of 55-90%, or 55-85%, or 55- 80%.Embodiment 30. The process of any of embodiments 1-26, wherein treating the provided Fischer Tropsch catalyst material with the carbiding gas stream is performed for a time sufficient to provide in the range of 60-95 atom% of the iron of the carbided Fischer- Tropsch catalyst material in a carbide form, e.g., in the range of 60-90%, or 60-85%, or 60- 80%.Embodiment 31 . The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, no more than 20 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., no more than 10 atom%.Embodiment 32. The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, no more than 5 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., no more than 2 atom%.Embodiment 33. The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 5 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., at least 10 atom%, or at least 15 atom%, or at least 20 atom%.Embodiment 34. The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 5- 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 5-45 atom%, or 5-40 atom%.Embodiment 35. The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of IQ- 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 10-45 atom%, or 10-40 atom%.Embodiment 36. The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 15- 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 15-45 atom%, or 15-40 atom%.Embodiment 37. The process of any of Embodiments 1-30, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, in the range of 20- 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form, e.g., 20-45 atom%, or 20-40 atom%.Embodiment 38. The process of any of embodiments 1-37, wherein treating the provided 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 39. The process of any of embodiments 1-38, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 45 atom%.Embodiment 40. The process of any of embodiments 1-38, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 50 atom%of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 55 atom%.Embodiment 41. The process of any of embodiments 1-38, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 65 atom%.Embodiment 42. The process of any of embodiments 1-38, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 75 atom%.Embodiment 43. The process of any of embodiments 1-38, wherein after treating the provided Fischer Tropsch catalyst material with the carbiding gas stream, at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 85 atom%.Embodiment 44. A carbided Fischer-Tropsch catalyst material comprising at least 10 wt% iron on an elemental basis exclusive of carbon, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 45 atom%.Embodiment 45. The carbided Fischer-Tropsch catalyst material of embodiment 44, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 55 atom%.Embodiment 46. The carbided Fischer-Tropsch catalyst material of embodiment 44, wherein at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 65 atom%.Embodiment 47. The carbided Fischer-Tropsch catalyst material of embodiment 44, wherein at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 75 atom%.Embodiment 48. The carbided Fischer-Tropsch catalyst material of embodiment 44, wherein at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-Fe5C2, e.g., at least 85 atom%.Embodiment 49. The carbided Fischer-Tropsch catalyst material of any of embodiments 44-48, having an amount of iron as described in embodiment 2 or embodiment 3.Embodiment 50. The carbided Fischer-Tropsch catalyst material of any of embodiments 43-49, having an amount of iron in carbided form as described in any of embodiments 27-30.Embodiment 51. The carbided Fischer-Tropsch catalyst material of any of embodiments 44-50, having an amount of iron in oxide form as described in any of embodiments 31-37.Embodiment 52. The Fischer-Tropsch catalyst material of any of embodiments 44-51 , prepared by a process according to any of embodiments 1-43.Embodiment 53. A process for providing a carbided Fischer-Tropsch catalyst material, the process comprising: providing a Fischer-Tropsch catalyst material comprising iron, 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 in the range of 160-300 °C for a time sufficient to provide a carbided Fischer-Tropsch catalyst material having at least 50 atom% of its iron in carbided form.Embodiment 54. The process of embodiment 53, wherein the provided Fischer-Tropsch catalyst material comprises an amount of iron as described in embodiment 2 or embodiment 3.Embodiment 55. The process of embodiment 53 or embodiment 54, wherein the provided Fischer-Tropsch catalyst material is a reduced Fischer-Tropsch catalyst material in which at least a portion of the iron of the provided Fischer-Tropsch catalyst material is in the form of metallic iron.Embodiment 56. The process of embodiment 55, wherein the reduced Fischer-Tropsch catalyst material is as described in or is prepared as described in any of embodiments 5-17.Embodiment 57. The process of embodiment 53 or embodiment 54, wherein providing the Fischer-Tropsch catalyst material comprises providing an oxidic Fischer-Tropsch catalyst material, and wherein the treatment with the carbiding gas stream is performed in the presence of hydrogen.Embodiment 58. The process of any of embodiments 53-57, wherein the carbiding gas stream further comprises hydrogen.Embodiment 59. The process of embodiment 58, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio in the range of 0.5:1 to 1.5:1.Embodiment 60. The process of embodiment 58, wherein the carbiding gas stream comprises hydrogen and carbon monoxide and / or carbon dioxide in a molar ratio of at least 1.5:1 (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 61 . The process of any of embodiments 53-60, wherein treating the provided catalyst material with the carbiding gas stream is conducted at a temperature in the range of 160-280 °C, e.g., 160-250 °C, or 160-230 °C or 160-220 °C, or 160-210 °C, or 160- 200 °C.Embodiment 62. The process of any of embodiments 53-60, wherein treating the provided catalyst material with the carbiding gas stream is conducted at a temperature in the range of 170-300 °C, e.g., 170-280 °C, or 170-250 °C, or 170-230 °C or 170-220 °C, or 170- 210 °C, or 170-200 °C.Embodiment 63 The process of any of embodiments 53-60, wherein treating the provided catalyst material with the carbiding gas stream is conducted at a temperature in the range of 180-300 °C, e.g., 180-280 °C, or 180-250 °C, or 180-230 °C or 180-220 °C, or 1 SO- 210 °C, or 180-200 °C.Embodiment 64. The process of any of embodiments 53-63, wherein treating the provided catalyst material with the carbiding gas stream is performed for a time sufficient toprovide the carbided Fischer-Tropsch catalyst with an amount of carbided iron as described in any of embodiments 27-30, and / or an amount of oxidic carbon as described in any of embodiments 31-37.Embodiment 65. The process of any of embodiments 53-64, wherein treating the provided 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 66. The process of any of embodiments 53-65, wherein after treating the provided catalyst material with the carbiding gas stream, at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of e-FesC and r|-Fe3C, e.g., at least 45 atom%.Embodiment 67. The process of any of embodiments 53-66, wherein after treating the provided catalyst material with the carbiding gas stream, at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-FesC and q-FesC, e.g., at least 55 atom%.Embodiment 68. The process of any of embodiments 53-66, wherein after treating the provided catalyst material with the carbiding gas stream, at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-FesC and q-FesC, e.g., at least 65 atom%.Embodiment 69. The process of any of embodiments 53-66, wherein after treating the provided catalyst material with the carbiding gas stream, at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-FesC and q-FesC, e.g., at least 75 atom%.Embodiment 70. The process of any of embodiments 53-66, wherein after treating the provided catalyst material with the carbiding gas stream, at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-FesC and q-FesC, e.g., at least 85 atom%.Embodiment 71. A carbided Fischer-Tropsch catalyst material comprising at least 10 wt% iron on an elemental basis exclusive of carbon, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and r|-Fe3C, e.g., at least 45 atom%.Embodiment 72. The carbided Fischer-Tropsch catalyst material of embodiment 71, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 55 atom%.Embodiment 73. The carbided Fischer-Tropsch catalyst material of embodiment 71, wherein at least 60 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 65 atom%.Embodiment 74. The carbided Fischer-Tropsch catalyst material of embodiment 71, wherein at least 70 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 75 atom%.Embodiment 75. The carbided Fischer-Tropsch catalyst material of embodiment 71, wherein at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-Fe3C and q-Fe3C, e.g., at least 85 atom%.Embodiment 76. The carbided Fischer-Tropsch catalyst material of any of embodiments 69-73, having an amount of iron as described in embodiment 2 or embodiment 3.Embodiment 77. The carbided Fischer-Tropsch catalyst material of any of embodiments 69-74, having an amount of iron in carbided form as described in any of embodiments 27-30.Embodiment 78. The carbided Fischer-Tropsch catalyst material of any of embodiments 69-75, having an amount of iron in oxide form as described in any of embodiments 31-37.Embodiment 79. The Fischer-Tropsch catalyst material of any of embodiments 71-78, prepared by a process according to any of embodiments 53-70.Embodiment 80. A process for performing a Fischer-Tropsch synthesis, the process comprising providing a carbided Fischer-Tropsch catalyst material of any of embodiments 44-52, or a carbided Fischer-Tropsch catalyst material made by a process of any of embodiments 1-43; contacting at a reaction temperature and pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2 and CO to provide a product stream comprising C5+ hydrocarbons.Embodiment 81 . A process for performing a Fischer-Tropsch synthesis, the process comprising providing a carbided Fischer-Tropsch catalyst material of any of embodiments 71-79, or a carbided Fischer-Tropsch catalyst material made by a process of any of embodiments 53-70; contacting at a reaction temperature and pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2 and CO to provide a product stream comprising C5+ hydrocarbons.Embodiment 82. The process of embodiment 80 or embodiment 81 , wherein the feed stream has a H2:CO ratio in the range of 0.5:1 to 6:1.Embodiment 83. The process of any of embodiments 80-82, 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 84. The process of any of embodiments 80-83, 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 85. The process of any of embodiments 80-84, 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 86. The process of any of embodiments 80-84, 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 87. The process of any of embodiments 80-86, 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 88. The process of embodiment 87, wherein the molar ratio of CO2 to CO in the feed stream is at least 0.5:1 , e.g., at least 0.7:1 or at least 1 :1.Embodiment 89. The process of embodiment 87, wherein the molar ratio of CO2 to CO in the feed stream is no more than 0.5:1 , e.g., no more than 0.3:1.Embodiment 90. The process of any of embodiments 80-89, 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 91 . The process of any of embodiments 80-90, 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 150-250°C, or 150-200°C, or 200-400 °C, or 200-350 °C, or 200-300°C, or 200-250 °C, or 250-400 °C, or 250-350 °C, or 250-300 °C, or 300-400 °C).Embodiment 93. The process of any of embodiments 80-90, wherein the reaction temperature is in the range of 200-350 °C.Embodiment 94. The process of any of embodiments 80-90, wherein the reaction temperature is in the range of 180-280 °C, e.g., 180-260 °C, or 180-240 °C, or 180-220 °C, or 200-280 °C, or 200-260 °C, or 200-240 °C.Embodiment 95. The process of any of embodiments 80-94, 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), e.g., in the range of 20-50 barg.Embodiment 96. The process of any of embodiments 80-95, wherein the Fischer- Tropsch reaction is conducted at a GHSV in the range of 1 ,000 to 2,000,000 IT1(e.g., in the range of 1 ,000 to 1 ,200,000 IT1, or 1 ,000 to 500,000 IT1, or 1 ,000 to 100,000 IT1, or 5,000 to 1 ,200,000 IT1, or 5,000 to 500,000 IT1, or 5,000 to 100,000 IT1, or 10,000 to 1 ,200,000 IT1, or 10,000 to 500,000 IT1, or 10,000 to 100,000 IT1).Embodiment 97. The process of any of embodiments 80-96, 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 98. The process of any of embodiments 80-96, 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 70%, or at least 80%.Embodiment 99. The process of any of embodiments 80-98, 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 100. The process of any of embodiments 80-99, 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 101. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 102. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 103. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 7%, e.g., no more than 6%.Embodiment 104. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), wherein the contacting ofthe Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with aC2-8 oxygenate selectivity of no more than 5%, e.g., no more than 4%.Embodiment 105. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 1-30%, e.g., 1-25%, or 1-20%.Embodiment 106. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 1-15%, e.g., 1-10%.Embodiment 107. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 1-5%, e.g., 1-4%.Embodiment 108. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 2-30%, e.g., 2-25%, or 2-20%.Embodiment 109. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 2-15%, e.g., 2-10%.Embodiment 110. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 2-5%, e.g., 2-4%.Embodiment 111. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 3-30%, e.g., 3-25%, or 3-20%.Embodiment 112. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 3-15%, e.g., 3-10%.Embodiment 113. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 3-5%.Embodiment 114. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 4-30%, e.g., 4-25%, or 4-20%.Embodiment 115. The process of any of embodiments 80-100 (especially embodiment 80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 4-15%, e.g., 4-10%.Embodiment 116. The process of any of embodiments 80-100 (especially embodiment80 and embodiments 82-100 as they depend from embodiment 80), 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 in the range of 4-8%, e.g., 4-6%.Embodiment 117. The process of any of embodiments 80-100 (especially embodiment81 and embodiments 82-100 as they depend from embodiment 81), 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 at least 7%, e.g., at least 9%.Embodiment 118. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 at least 11%, e.g., at least 13%.Embodiment 119. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 at least 15%, e.g., at least 17%.Embodiment 120. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 7-30%, e.g., 9-30%.Embodiment 121. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 11-30%, e.g., 13-30%.Embodiment 122. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 15-30%, e.g., 17-30%.Embodiment 123. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 7-27%, e.g., 9-27%.Embodiment 124. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 11-27%, e.g., 13-27%.Embodiment 125. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), wherein the contactingof the Fischer-Tropsch catalyst with the feed stream to provide the product stream is performed with a C2-8 oxygenate selectivity in the range of 15-27%, e.g., 17-27%.Embodiment 126. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 7-24%, e.g., 9-24%.Embodiment 127. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 11-24%, e.g., 13-24%.Embodiment 128. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 15-24%, e.g., 17-24%.Embodiment 129. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 7-22%, e.g., 9-22%.Embodiment 130. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 11-22%, e.g., 13-22%.Embodiment 131. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 15-22%, e.g., 17-22%.Embodiment 132. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 7-20%, e.g., 9-20%.Embodiment 133. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 11-20%, e.g., 13-20%.Embodiment 134. The process of any of embodiments 80-100 (especially embodiment 81 and embodiments 82-100 as they depend from embodiment 81), 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 in the range of 15-20%, e.g., 17-20%.Embodiment 135. The process of any of embodiments 80-132, further comprising separating at least a portion of C1-C4 hydrocarbons from the product stream to provide a light hydrocarbon stream.Embodiment 136. The process of embodiment 135, further comprising burning at least a portion of the light hydrocarbon stream to provide energy, e.g., heat energy or electrical energy.Embodiment 137. The process of embodiment 136, wherein the heat energy is used to heat the feed stream.Embodiment 138. The process of any of embodiments 80-137, further comprising recycling at least a portion of H2 of the product stream to the feed stream.Embodiment 139. The process of any of embodiments 80-138, further comprising recycling at least a portion of CO of the product stream to the feed stream.Embodiment 140. The process of any of embodiments 80-139, further comprising recycling at least a portion of inerts of the product stream to the feed stream.Embodiment 141. The process of any of embodiments 80-140, wherein one or more products are provided from at least a portion of C5+ hydrocarbons of the product stream.Embodiment 142. The process of embodiment 141 , wherein the one or more products include fuels (e.g., gasoline, diesel fuel, aviation fuel), lubricants and waxes.Embodiment 143. The process of any of embodiments 80-142, further comprising hydroprocessing at least a portion of C5+ hydrocarbons of the product stream.Embodiment 144. The process of any of embodiments 80-143, wherein at least part of the H2of the feed stream is from a renewable source.Embodiment 145. The process of any of embodiment 80-143, wherein at least a portion of the hydrogen of the feed stream is green hydrogen.Embodiment 146. The process of any of embodiment 80-143, wherein at least a portion of the hydrogen of the feed stream is blue hydrogen.Embodiment 147. The process of any of embodiment 80-143, 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 148. The process of any of embodiments 80-147, further comprising providing at least a portion of H2to the first feed stream and / or the second feed stream by electrolysis of water.Embodiment 149. The process of embodiment 148, wherein the electrolysis of water is performed using at least partially electricity from a renewable source.Embodiment 150. The process of embodiment 149 or embodiment 150, 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).Embodiment 151. A process for performing a sequence of Fischer Tropsch processes comprising: performing a first Fischer-Tropsch process according to embodiment 80, or any of embodiments 82-150 as dependent from embodiment 80; then performing a second Fischer-Tropsch process according to embodiment 81 , or any of embodiments 82-150 as dependent from embodiment 81 , wherein the carbided Fischer-Tropsch catalyst material used in the second Fischer- Tropsch process is provided by regenerating the Fischer-Tropsch catalystmaterial used in the first Fischer-Tropsch process to a substantially oxidic form, then carbiding the substantially oxidic Fischer-Tropsch catalyst material to provide the carbided Fischer-Tropsch catalyst material used in the second Fischer-Tropsch catalyst process.Embodiment 152. A process for performing a sequence of Fischer Tropsch processes comprising: performing a first Fischer-Tropsch process according to embodiment 81, or any of embodiments 82-150 as dependent from embodiment 81 ; then performing a second Fischer-Tropsch process according to embodiment 80, or any of embodiments 82-150 as dependent from embodiment 80, wherein the carbided Fischer-Tropsch catalyst material used in the second Fischer- Tropsch process is provided by carbiding the Fischer-Tropsch catalyst material used in the first Fischer-Tropsch process to provide the carbided Fischer-Tropsch catalyst material used in the second Fischer-Tropsch catalyst process.Embodiment 153. The process of embodiment 152, wherein carbiding the Fischer- Tropsch catalyst material used in the second Fischer-Tropsch process comprises regenerating the Fischer-Tropsch catalyst material used in the first Fischer-Tropsch process to a substantially oxidic form, then carbiding that substantially oxidic Fischer-Tropsch catalyst materialEmbodiment 154. The process of embodiment 153, wherein regenerating the Fischer- Tropsch catalyst material used in the first Fischer-Tropsch process to a substantially oxidic form is performed by treatment with an oxidizing gas (e.g., comprising oxygen) at a temperature in excess of 400 °C.Embodiment 155. The process of any of embodiments 151, 153 and 154, wherein at least 50 atom% of the iron of the substantially oxidic Fischer-Tropsch catalyst material is in an oxidic form, e.g., at least 70 atom%, or at least 90 atom%, as determined by Mbssbauer spectroscopy.Embodiment 156. The process of any of embodiments 151-155, performed without removing the Fischer-Tropsch catalyst material from a reactor in which the first and second Fischer-Tropsch processes are performed.

[0138] 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.

[0139] 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 indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.

[0140] All processes described herein can be performed in any suitable order of steps unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.

[0141] 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.

[0142] 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.

[0143] 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.

[0144] Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

[0145] 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.

[0146] 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 byapplicable 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.

[0147] 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

What is claimed is: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, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of e-FesC and q- FesC; and contacting at a reaction temperature and pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2 and CO to provide a product stream comprising C5+ hydrocarbons with a C2-8 oxygenate selectivity of at least 10%.Claim 2. The process of Claim 1 , wherein at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of E- FesC and q-FesC, e.g., at least 85 atom%.Claim 3. The process of Claim 1 or Claim 2, wherein the carbided Fischer-Tropsch catalyst material comprises at least 40 wt% iron on an elemental basis exclusive of carbon.Claim 4. The process of any of Claims 1-3, wherein at least 5 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in an oxide form.Claim 5. The process of any of Claims 1-4, wherein the carbided Fischer-Tropsch catalyst material is provided by a process comprising: providing a Fischer-Tropsch catalyst material comprising at least 10 wt% iron on an elemental basis exclusive of carbon, and treating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide, at a temperature in the range of 160-300 °C for a time sufficient to provide a carbided Fischer-Tropsch catalyst material having at least 50 atom% of its iron in carbided form, wherein at least 40 atom% (e.g., at least 80% or at least 85%) of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of one or more of s-FesC and q-FesC.Claim 6. The process of claim 5, wherein the treatment with the carbiding gas stream is performed at a temperature in the range of 160-250 °C.Claim 7. 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, wherein at least 50 atom% of the iron of the carbided Fischer-Tropsch catalyst material is in carbide form, and wherein at least 40 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2; and contacting at a reaction temperature and pressure the carbided Fischer-Tropsch catalyst material with a feed stream comprising H2and CO to provide a product stream comprising C5+ hydrocarbons with a C2-8 oxygenate selectivity of no more than 7%.Claim 8. The process of Claim 7, wherein at least 80 atom% of the iron of the carbided Fischer-Tropsch catalyst material that is in a carbide form is in the form of x-FesC2, e.g., at least 85 atom%.Claim 9. The process of Claim 7 or Claim 8, wherein the carbided Fischer-Tropsch catalyst material comprises at least 40 wt% iron on an elemental basis exclusive of carbonClaim 10. The process of any of Claims 7-9, wherein the carbided Fischer-Tropsch catalyst material is provided by a process comprising: providing a Fischer-Tropsch catalyst material comprising at least 10 wt% iron on an elemental basis exclusive of carbon; and treating the Fischer-Tropsch catalyst material with a carbiding gas stream comprising carbon monoxide and / or carbon dioxide, at a temperature of at least 300 °C for a time sufficient to provide a carbided Fischer-Tropsch catalyst material having at least 50 atom% of its iron in carbided form and at least 40 atom% of its iron that is in a carbide form in the form of x-FesC2.Claim 11. The process of any of Claims 5, 6 and 10, wherein the provided Fischer- Tropsch catalyst material is a reduced Fischer-Tropsch catalyst material in which at least 70 atom% of the iron of the reduced Fischer-Tropsch catalyst material is in the form of metallic iron.Claim 12. The process of any of claims 5, 6 and 10, wherein providing the reduced Fischer-Tropsch catalyst material contacting an oxidic Fischer-Tropsch catalyst material comprising oxidic iron with a reducing gas stream comprising hydrogen for a time and at a temperature sufficient to provide at least a portion of the iron in a metallic state, and wherein the contacting with the reducing gas stream is performed in the substantial absence of carbon monoxide and / or carbon dioxide.Claim 13. The process of any of Claims 5, 6 and 10, wherein providing the Fischer- Tropsch catalyst material comprises providing an oxidic Fischer-Tropsch catalyst material, and wherein the treatment with the carbiding gas stream is performed in the presence of hydrogen.Claim 14. A process for performing a sequence of Fischer Tropsch processes comprising: performing a first Fischer-Tropsch process according to any of Claims 1-6; then performing a second Fischer-Tropsch process according to any of Claims 7-10, wherein the carbided Fischer-Tropsch catalyst material used in the second Fischer- Tropsch process is provided by carbiding the Fischer-Tropsch catalyst material used in the first Fischer-Tropsch process to provide the carbided Fischer-Tropsch catalyst material used in the second Fischer-Tropsch catalyst process.Claim 15. The process of Claim 14, wherein carbiding the Fischer-Tropsch catalyst material used in the second Fischer-Tropsch process comprises regenerating the Fischer- Tropsch catalyst material used in the first Fischer-Tropsch process to a substantially oxidic form, then carbiding that substantially oxidic Fischer-Tropsch catalyst material.

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