Method, system and catalyst combination

Abstract

Provided herein is a method for producing a product comprising one or more alkanes, said method comprising: contacting a feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide with a first catalyst composition, wherein the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species, to provide an intermediate product comprising olefins; optionally subjecting the intermediate product to one or more fractionating steps to provide a fractionated intermediate product; and contacting said optionally fractionated intermediate product with a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

Description

METHOD, SYSTEM AND CATALYST COMBINATIONINTRODUCTION

[0001] The present invention relates to a method for producing a product comprising one or more alkanes. The method uses a combination of catalyst compositions in order to convert a feedstock comprising carbon dioxide and / or carbon monoxide and hydrogen to one or more alkanes, suitably liquid alkane products.BACKGROUND OF THE INVENTION

[0002] Hydrogenation of carbon dioxide to hydrocarbons usually proceeds through tandem catalysis process involving a reverse water gas shift (RWGS) reaction to produce CO, and subsequent CO hydrogenation to hydrocarbons via Fischer-Tropsch reaction. The Fischer-Tropsch reaction is a chemical process that converts a mixture of carbon monoxide and hydrogen, known as syngas, into hydrocarbons. The reaction is typically carried out in the presence of a metal catalyst at elevated temperatures and pressures.

[0003] The product distribution of the Fischer-Tropsch reaction is complex and depends on a number of factors, including the type of catalyst, the reaction temperature and pressure, and the composition of the syngas feedstock. The main products from the Fischer-Tropsch reaction, whether starting from carbon dioxide or carbon monoxide, are usually saturated or unsaturated, straight-chain hydrocarbons.

[0004] Unsaturated hydrocarbons are problematic as fuel components because they are more reactive than saturated hydrocarbons. This means they are more likely to form gums and varnishes, which can damage engine components and complicate storage and transport, and also are more likely to undergo unwanted reactions, such as oxidation, which can lead to engine knock and other problems.

[0005] Consequently, Fischer-Tropsch products intended for fuel applications often require further hydrogenation to turn the unsaturated hydrocarbons into saturated hydrocarbons, which are more stable fuel components.

[0006] Furthermore, branched-chain hydrocarbons have several advantages over unbranched hydrocarbons in fuels, for example, higher octane rating, lower freezing point, better cold-start performance and reduced emissions. Therefore, Fischer-Tropsch hydrocarbon products usually require further hydro-isomerisation to convert straightchain products into branched products, such as branched paraffins.

[0007] The present invention provides a method, system and catalyst combination for preparing a hydrocarbon product comprising alkane products, suitably branched, liquid alkane products, suitable for use as fuels.SUMMARY OF THE INVENTION

[0008] The methods of the present disclosure can be used for producing a product comprising one or more alkanes. The method uses a combination of catalyst compositions in order to convert a feedstock comprising carbon dioxide and / or carbon monoxide and hydrogen to one or more alkanes, suitably liquid alkane products. These and other aspects of the disclosed subject matter are discussed in more detail below.

[0009] Although embodiments of the present disclosure can be used in relation to a feedstock comprising carbon monoxide and hydrogen, it is preferred that the feedstock comprises carbon dioxide and hydrogen, or comprises carbon dioxide and carbon monoxide and hydrogen. The specific combinations of catalyst compositions described and claimed herein are designed for CO2 Fischer-Tropsch and are particularly beneficial in such methods.

[0010] It is a benefit of the present invention that a combination of catalyst compositions is used, where a first catalyst converts the feedstock comprising carbon dioxide and / or carbon monoxide and hydrogen into alkene-richhydrocarbons, and a second catalyst converts these alkenes into alkanes. This may be described as hydrotreatment or fuel upgrading. By increasing the hydrogen content, alkenes are converted to alkanes, leading to an improvement in quality of the fuel. The second catalyst may also perform isomerisation, transforming straight chain alkanes into branched alkanes. This further helps improve fuel quality.

[0011] Crude fuel from Fischer-Tropsch reactions typically contains some oxygenates as impurities, which need to be removed through additional hydro-deoxygenation steps. In the present invention, the amount of oxygenates is reduced, making the subsequent after-treatment easier. This is a further advantage of the present invention.

[0012] In a first aspect, the presently disclosed subject matter provides a method for producing a product comprising one or more alkanes, said method comprising:contacting a feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide with a first catalyst composition, wherein the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species, to provide an intermediate product comprising olefins; optionally subjecting the intermediate product to one or more fractionating steps to provide a fractionated intermediate product; andcontacting said optionally fractionated intermediate product with a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

[0013] In a further aspect, the present disclosure provides a catalyst combination comprising a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species; and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

[0014] In a further aspect, the present disclosure provides a system for the production of a product comprising one or more alkanes comprising one or more reactors, a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species; and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species; wherein the first and second catalyst composition are contained in one or more of the reactors.

[0015] In all aspects of the invention, in one embodiment the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, and a copper species.

[0016] In all aspects of the present invention, the first catalyst is an iron-based Fischer-Tropsch catalyst that converts the feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide to alkenes (olefins), and preferably that converts a feedstock comprising (i) hydrogen and (ii) carbon dioxide to alkenes (olefins). To achieve this, it is preferred that the first catalyst comprises about 50 wt. % or more of iron, such as about 50 to about 90 wt. % of iron. It is preferred that the first catalyst is a bulk catalyst, i.e. there is no support present. Using the first catalyst in unsupported form shows superior selectivity toward liquid hydrocarbons, particularly in the jet- fuel range (C8-C16).

[0017] In all aspects of the present invention, the second catalyst composition comprises both a metal species and a solid acid. As the skilled person will appreciate, a solid acid catalyst can have Bronsted acid sites, which donate protons, and / or Lewis acid sites, which accept electron pairs. The overall acidity of a catalyst depends on both the number and strength of these acid sites. The second catalyst is primarily used for hydrogenating alkenes (olefins) to alkanes (paraffins). To achieve this function, the metal species in the second catalyst is selected from one or more of a platinum, a palladium, and a nickel species or a cobalt species; it is preferred that the metal species in the second catalyst is selected from one or more of a platinum, a palladium, and a nickel species. In one embodiment, no further metal species is present in an amount of more than lwt%. In one embodiment, no further metal species is present.

[0018] Preferred, suitable, and optional features of any one particular aspect of the present invention are also preferred, suitable, and optional features of any other aspect.BRIEF DESCRIPTION OF THE DRA WINGS

[0019] Figure 1 shows a process flow diagram for a CO2 and / or CO hydrogenation comprising a catalyst combination in a single reactor.

[0020] Figure 2a shows the performance of Catalyst 0 only for the hydrogenation of carbon dioxide, with respect to the conversion of hydrogen and CO2.

[0021] Figure 2b shows the performance of Catalyst 0 only for the hydrogenation of carbon dioxide, in with respect to the product selectivity.

[0022] Figure 2c shows the performance of Catalyst 0 only for the hydrogenation of carbon dioxide, with respect to molar ratios of olefin-to -paraffin (i.e., alkene to alkane) for C2-C4 products.

[0023] Figure 3a shows the performance of Catalyst 0 and Catalyst 01 in the same reactor for the hydrogenation of carbon dioxide, with respect to conversion of hydrogen and CO2 (Fig. 3a).

[0024] Figure 3b shows the performance of Catalyst 0 and Catalyst 01 in the same reactor for the hydrogenation of carbon dioxide, with respect to product selectivity (Fig. 3b).

[0025] Figure 3c shows the performance of Catalyst 0 and Catalyst 01 in the same reactor for the hydrogenation of carbon dioxide, with respect to molar ratios of olefin-to-paraffin for C2-C4 products (Fig. 3c).

[0026] Figure 4 shows the GC-MS total ion chromatogram (TIC) of the liquid products from CO2 hydrogenation with Catalyst 0 only.

[0027] Figure 5 shows the GC-MS total ion chromatogram (TIC) of the liquid products from CO2 hydrogenation with Catalyst 0+01.

[0028] Figure 6 shows a process flow diagram for a CO2 and / or CO hydrogenation comprising a catalyst combination in separate reactors.

[0029] Figure 7 shows an alternative embodiment of a process for CO2 and / or CO hydrogenation comprising a catalyst combination in separate reactors where the output of the first reactor is fractionated before being fed to the second reactor.

[0030] Figure 8 shows an alternative embodiment of a process for CO2 and / or CO hydrogenation comprising a catalyst combination in a single reactor which comprises a recycle feed from a reforming reactor.

[0031] Figure 9 shows results of a stability evaluation of catalysts Fe-Co-Mn-K and RHI-DW130S mixed in one catalyst bed for a CO2 hydrogenation reaction, in particular % conversion of CO2 and H2as a function ofreaction time for the hydrogenation of CO2 (Fig. 9a), selectivity of various hydrocarbon products with reaction time for the hydrogenation of CO2 (Fig. 9b), and molar ratio of olefin-to-paraffin for the C2-C4 range with reaction time for the hydrogenation of CO2 (Fig. 9c).

[0032] Figure 10 shows a process flow diagram for a CO2 and / or CO hydrogenation reaction comprising a tandem reactors rig.

[0033] Figure 11 shows a process flow diagram for a CO2 and / or CO hydrogenation reaction comprising a recycling loop.

[0034] Figure 12 is a table setting out formulae for a number of zeolites that can be used as the solid acid catalyst.DETAILED DESCRIPTION OF THE INVENTIONDefinitions

[0035] As used herein the term “solid” describes a material which is solid at standard ambient temperature and pressure (SATP), i.e. at a temperature of 298.15 K (25 °C) and at 100,000 Pa (1 bar, 14.5 psi, 0.9869 atm).

[0036] As used herein the term “liquid” describes to a material which is liquid at standard ambient temperature and pressure (SATP), i.e. at a temperature of 298.15 K (25 °C) and at 100,000 Pa (1 bar, 14.5 psi, 0.9869 atm).

[0037] As used herein, the term “selectivity” refers to the amount of production of a particular product as a proportion of the total of a given product.

[0038] As used herein the term “hydrocarbon” refers to organic compounds consisting of carbon and hydrogen.

[0039] For the avoidance of doubt, hydrocarbons include straight-chained and branched, saturated and unsaturated hydrocarbon compounds, including alkanes, alkenes, and alkynes, as well as saturated and unsaturated cyclic aliphatic hydrocarbon compounds, including cycloalkanes, cycloalkenes and cycloalkynes, as well as hydrocarbon polymers, for instance polyolefins.

[0040] Hydrocarbons also include aromatic hydrocarbons, i.e. hydrocarbons comprising one or more aromatic rings. The aromatic rings may be monocyclic or polycyclic.

[0041] Aliphatic hydrocarbons which are substituted with one or more aromatic hydrocarbons, and aromatic hydrocarbons which are substituted with one or more aliphatic hydrocarbons, are also of course encompassed by the term “hydrocarbon” (such compounds consisting only of carbon and hydrogen) as are straight-chained or branched aliphatic hydrocarbons that are substituted with one or more cyclic aliphatic hydrocarbons, and cyclic aliphatic hydrocarbons that are substituted with one or more straight-chained or branched aliphatic hydrocarbons.

[0042] A “Cn-m hydrocarbon” or “Cn-Cmhydrocarbon” or “Cn-Cm hydrocarbon”, where n and m are integers, is a hydrocarbon, as defined above, having from n to m carbon atoms. For instance, a C5-16 hydrocarbon is a hydrocarbon as defined above which has from 5 to 16 carbon atoms, a C5+ hydrocarbon is a hydrocarbon as defined above which has 5 or more carbon atoms etc.

[0043] The term “alkane”, as used herein, refers to a linear or branched chain saturated hydrocarbon compound. Examples of alkanes are for instance, butane, pentane, hexane, heptane, octane, nonane, decane, undecane, dodecane, tridecane and tetradecane. Alkanes such as dimethylbutane may be one or more of the possible isomers of this compound. Thus, dimethylbutane includes 2,3-dimethybutane and 2,2-dimethylbutane. This also applies for all hydrocarbon compounds referred to herein including cycloalkane, alkene, cycloalkene.

[0044] As used herein, the term “paraffin” refers to an acyclic saturated hydrocarbon. A paraffin may be linear or branched. To be suitable for use as a liquid fuel, the paraffin is a liquid paraffin, i.e. a paraffin having 5 or more carbon atoms (C5+). The terms “paraffin” and “alkane” may be used interchangeably.

[0045] The term “cycloalkane”, as used herein, refers to a saturated cyclic aliphatic hydrocarbon compound. Examples of cycloalkanes include cyclopropane, cyclobutane, cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane. Examples of a C5-8 cycloalkane include cyclopentane, cyclohexane, methylcyclopentane, cycloheptane, methylcyclohexane, dimethylcyclopentane and cyclooctane. The terms “cycloalkane” and “naphthene” may be used interchangeably.

[0046] The term “alkene”, as used herein, refers to a linear or branched chain hydrocarbon compound comprising one or more carbon-carbon double bonds. Examples of alkenes are butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene and tetradecene. Alkenes typically comprise one or two double bonds. The one or more double bonds may be at any position in the hydrocarbon chain. The alkenes may be cis- or trans-alkenes (or as defined using E- and Z- nomenclature). An alkene comprising a terminal double bond may be referred to as an “alk-l-ene” (e.g. hex-l-ene), a “terminal alkene” (or a “terminal olefin”), or an “alpha-alkene” (or an “alpha-olefin”). The term “alkene”, as used herein also often includes cycloalkenes. The terms “alkene” and “olefin” may be used interchangeably.

[0047] The term “cycloalkene”, as used herein, refers to partially unsaturated cyclic hydrocarbon compound. Examples of a cycloalkene includes cyclobutene, cyclopentene, cyclohexene, cyclohexa- 1,3 -diene, methylcyclopentene, cycloheptene, methylcyclohexene, dimethylcyclopentene and cyclooctene. A cycloalkene may comprise one or two double bonds.

[0048] The term “aromatic hydrocarbon” or “aromatic hydrocarbon compound”, as used herein, refers to a hydrocarbon compound comprising one or more aromatic rings. The aromatic rings may be monocyclic or polycyclic. Typically, an aromatic compound comprises a benzene ring. An aromatic compound may, for instance, be a C6-14 aromatic compound, a C6-12 aromatic compound or a C6-10 aromatic compound. Examples of C6-14 aromatic compounds are benzene, toluene, xylene, ethylbenzene, methylethylbenzene, diethylbenzene, naphthalene, methylnaphthalene, ethylnaphthalene and anthracene.

[0049] As used herein, a superscript of “=” indicates the molecule having at least one double bond (so being an alkene), and a superscript of “0” indicates the molecule having no (zero) double bonds (so being an alkane). As such, C2-C40indicates alkanes with chain lengths of 2 to 4, and C2-C4= indicates alkenes with chain lengths of 2 to 4, for example.

[0050] As used herein, the term “metal species” refers to any compound comprising a metal. As such, a metal species includes the elemental metal, metal oxides and other compounds comprising a metal, for example, metal salts, alloys, hydroxides, carbides, borides, phosphides, silicides and hydrides. When a specific example of a metal species is stated, said term refers to all compounds comprising that metal, e.g. iron species includes elemental iron, iron oxides, iron salts, iron alloys, iron hydroxides, iron carbides, iron borides, iron silicides and iron hydrides for instance. Examples of salts include nitrates, halides (e.g. chlorides), sulphates, and carbonates.

[0051] As used herein, the term “molar ratio” refers to a ratio between the amounts in moles of any two or more components comprised in a composition, reaction, or product distribution. A molar ratio may be represented as a single number, e.g. 3, which may also be represented as 3: 1 and is a 3 to 1 ratio of a first component and a second component. In instances where more than two compounds are present, molar ratio may be represented as a seriesof ratios, e.g. 100:2: 10: 10, which is a 100 to 2 to 10 to 10 ratio between a first component, a second component, a third component, and a fourth component.

[0052] The term “about” or “approximately” means within an acceptable error range for the particular value as determined by one of ordinary skill in the art, which will depend in part on how the value is measured or determined, i.e., the limitations of the measurement system. For example, “about” can mean within three or more than three standard deviations, per the practice in the art. Alternatively, “about” can mean a range of up to 20%, preferably up to 10%, more preferably up to 5%, and more preferably still up to 1% of a given value. Also, particularly with respect to systems or processes, the term can mean within an order of magnitude, preferably within five-fold, and more preferably within two-fold, of a value.

[0053] As used herein, the terms “comprises,” “comprising,” or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can include other elements not expressly listed or inherent to such process, method, article, or apparatus.

[0054] In the detailed description herein, references to “embodiment,” “an embodiment,” “one embodiment,” “in various embodiments,” etc., indicate that the embodiment(s) described can include a particular feature, structure, or characteristic, but every embodiment might not necessarily include the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described. After reading the description, it will be apparent to one skilled in the relevant art(s) how to implement the disclosure in alternative embodiments.

[0055] It will be appreciated that the term “Fischer-Tropsch reaction” (FT reaction) is conventionally used to mean a hydrogenation reaction whereby hydrogen and carbon monoxide (syngas) are reacted to form hydrocarbon chains, of varying length, and water. This CO FT reaction (“conventional” FT reaction) is well known in the art and is a multi-step reaction involving several intermediate compounds. New C-C bonds of a hydrocarbon chain are formed through the initial addition of hydrogen to carbon and oxygen. The “CO2 Fischer-Tropsch”, “CO2 FT” or “COXFT” hydrogenation reaction described herein may be considered similar to a conventional FT reaction, but using CO2 in place of some or all of the CO. CO2 FT reactions may also be described as CO2 hydrogenation reactions.

[0056] The skilled person will be aware that oxygenates are compounds derived from hydrocarbons and containing at least one oxygen atom, for example alcohols and esters. Crude fuel from CO2-FT typically contains some oxygenates as impurities, which are then removed through additional hydro-deoxygenation steps. In the present invention, the amount of oxygenates is reduced, making the subsequent after-treatment easier. This is one of the advantages of the present invention.

[0057] A solid acid catalyst is a heterogeneous catalyst that provides acid sites, which are essential for the catalytic function. The solid acid catalyst can have Bronsted acid sites, which donate protons, and / or Lewis acid sites, which accept electron pairs. The overall acidity of a catalyst depends on both the number and strength of these acid sites. Examples of solid acids are aluminosilicate catalysts (such as zeolites), silicon aluminium phosphate molecular sieves, transition metal oxides such as titania, zirconia, and niobia, SiO2. WO3, as well as aluminium oxide, and sulfated metal oxides.

[0058] Zeolites are crystalline microporous aluminosilicates. The Si / Al ratio directly impacts the Bronsted acidity of zeolites and their physical and chemical properties. Zeolites with a low Si / Al ratio, e.g. from 1 to 5, exhibit strong acidity due to their greater number of Bronsted acid sites. Zeolites with intermediate Si / Al ratios, e.g. in the range of 10 to 50, combine strong acidity with higher thermal and hydrothermal stability. Zeolites with a high Si / Al ratio (>100) have lower overall acidity. Zeolites can be provided in protonated or unprotonated form.

[0059] Transition metal oxides exhibit Lewis and Bronsted acidity depending on their surface structure and chemical composition. The strength of acidity is influenced by electronegativity, the oxidation state, the surface structure, and defect chemistry.Method

[0060] In a first aspect, the present disclosure provides a method for producing a product comprising one or more alkanes, said method comprising:contacting a feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide with a first catalyst composition, wherein the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species, to provide an intermediate product comprising olefins; optionally subjecting the intermediate product to one or more fractionating steps to provide a fractionated intermediate product; andcontacting said optionally fractionated intermediate product with a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species, so as to form a product comprising one or more alkanes.

[0061] In one embodiment, the further transition metal species is selected from one or more of a manganese species, a cobalt species, a zinc species and a copper species.

[0062] In some embodiments, the one or more alkanes are one or more saturated acyclic alkanes, which may be linear or branched. In some embodiments, the one or more alkanes is one or more linear or branched alkane. In another embodiment, the one or more alkanes is a mixture of linear and branched alkanes.

[0063] The product comprising one or more alkanes may be a liquid product or may comprise a liquid product, e.g. it may comprise some product in liquid form and some product in gas form. The gas and liquid phases of the product may be separated. Liquid alkanes may be preferred as a product. Reference may be made to the “total liquid product” meaning the liquid phase of the product as obtained, following the step of contacting said optionally fractionated intermediate product with said second catalyst composition. The liquid phase of the product as obtained suitably comprises alkanes.

[0064] In some embodiments, the product comprises at least about 80 wt.% of alkanes in the total liquid product. Suitably, the product comprises at least about 85 wt.% of alkanes, more suitably at least about 90 wt. % in the total liquid product.

[0065] In another embodiment, the product comprises about 80 wt.% to about 100 wt. % of alkanes in the total liquid product, suitably about 85 wt.% to about 100 wt. %, suitably about 90 wt.% to about 100 wt. % of alkanes.

[0066] In another embodiment, the product comprises about 80 wt.% to about 99 wt. % of alkanes in the total liquid product, suitably about 85 wt.% to about 99 wt. %, suitably about 90 wt.% to about 99 wt. % of alkanes in the total liquid product.

[0067] In some embodiments, the product comprises C5-16 alkanes. In some embodiments, the product comprises at least about 60 wt. % of C5-16 alkanes in the total liquid product. Suitably, the product comprises at least about 65 wt.% of C5-16 alkanes, more suitably at least about 70 wt. % in the total liquid product, more suitably at least about 75 wt. % in the total liquid product, more suitably at least about 80 wt. % in the total liquid product.

[0068] In another embodiment, the product comprises about 60 wt. % to about 95 wt.% of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 60 wt.% to about 90 wt. % of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 60 wt.% to about 85 wt. % of C5-16 alkanes in the total liquid product.

[0069] In another embodiment, the product comprises about 70 wt. % to about 95 wt.% of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 70 wt.% to about 90 wt. % of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 70 wt.% to about 85 wt. % of C5-16 alkanes in the total liquid product.

[0070] In another embodiment, the product comprises about 75 wt. % to about 95 wt.% of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 75 wt.% to about 90 wt. % of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 75 wt.% to about 85 wt. % of C5-16 alkanes in the total liquid product.

[0071] In another embodiment, the product comprises about 80 wt. % to about 95 wt.% of C5-16 alkanes in the total liquid product. Suitably, the product comprises about 80 wt.% to about 90 wt. % of C5-16 alkanes in the total liquid product.

[0072] In one embodiment, the first catalyst is provided in bulk form, i.e. it is unsupported. It has surprisingly been found that by using the first catalyst in bulk form, superior selectivity toward liquid hydrocarbons is exhibited, particularly in the jet-fuel range (C8-C16).

[0073] In some embodiments, the product comprises branched alkanes, suitably C5+ branched alkanes or Cs-ie branched alkanes. In some embodiments, the product comprises at least about 15 wt.% of branched alkanes, suitably at least about 18 wt. % of branched alkanes, suitably at least about 20 wt. % of branched alkanes, suitably at least about 25 wt. % of branched alkanes, suitably at least about 30 wt. % of branched alkanes in the total liquid product.

[0074] In another embodiment, the product comprises about 15 wt. % to about 35 wt.% of branched alkanes in the total liquid product. Suitably, the product comprises about 15 wt.% to about 30 wt. %, or about 15 wt.% to about 25 wt. %, or about 20 wt.% to about 25 wt. %, of branched alkanes in the total liquid product.

[0075] In some embodiments, the product comprises linear alkanes, suitably C5+ linear alkanes or C8-16 linear alkanes. In some embodiments, the product comprises at least about 50 wt.% of linear alkanes, suitably at least about 60 wt. % of linear alkanes, suitably at least about 65 wt. % of linear alkanes, suitably at least about 70 wt. % of linear alkanes, suitably at least about 75 wt. % of linear alkanes in the total liquid product.

[0076] In another embodiment, the product comprises about 50 wt. % to about 80 wt.% of linear alkanes in the total liquid product. Suitably, the product comprises about 50 wt.% to about 70 wt. %, or about 50 wt.% to about 60 wt. %, or about 60 wt.% to about 80 wt. %, of linear alkanes in the total liquid product.

[0077] In some embodiments, the product has a weight ratio of alkene:alkane of about 0.5 or less, suitably about 0.1 or less, suitably about 0.05 or less, suitably about 0.03 or less, suitably 0.02 or less, suitably about 0.01 or less.

[0078] In some embodiments, the product has a weight ratio of alkene:alkane of about 0.5 to about 0.01, suitably about 0.3 or to about 0.01, suitably about 0.2 to about 0.01, suitably about 0.1 or to about 0.01, suitably about 0.05 to about 0.01.

[0079] In some embodiments, the feedstock comprises carbon dioxide and hydrogen. In one embodiment, the feedstock has a molar ratio of hydrogen to carbon dioxide of from 1.5 to 4. The feedstock may have a molar ratio of hydrogen to carbon dioxide of about 2 to about 3. Suitably the feedstock has a molar ratio of hydrogen to carbon dioxide of about 3.

[0080] In some embodiments, the feedstock comprises carbon monoxide and hydrogen. In one embodiment, the feedstock has a molar ratio of hydrogen to carbon monoxide of from 1.5 to 4. The feedstock may have a molar ratio of hydrogen to carbon monoxide of about 2 to about 3. Suitably the feedstock has a molar ratio of hydrogen to carbon monoxide of about 2.

[0081] In some embodiments, the feedstock comprises carbon dioxide, carbon monoxide and hydrogen. The ratio of hydrogen to carbon dioxide may be as described above. The ratio of hydrogen to carbon monoxide may be as described above.

[0082] It is preferred that the feedstock comprises carbon dioxide and hydrogen, and optionally further comprises carbon monoxide. The specific combinations of catalyst compositions described and claimed herein are designed for CO2 Fischer-Tropsch and are particularly beneficial in such methods.

[0083] In some embodiments, the carbon dioxide is obtained from a carbon dioxide capture system, such as a direct air capture system or a system which captures from a point source such as a flue gas or biogas. In another embodiment, the carbon dioxide may be obtained from a chemical process, such as methanol reforming, methane reforming, or gasification of waste of biomass.

[0084] In some embodiments, the intermediate product comprises C5+ olefins. In another embodiment, the intermediate product comprises C5-16 olefins. In another embodiment, the intermediate product comprises Cs-ie olefins.

[0085] In one embodiment, the first catalyst is provided in bulk form, i.e. it is unsupported. It has surprisingly been found that by using the first catalyst in bulk form, superior selectivity toward liquid hydrocarbons is exhibited, particularly in the jet-fuel range (C8-C16). By using the first catalyst in bulk form, there is also higher activity than when the first catalyst is used in supported form.

[0086] It will be appreciated that the method of the present disclosure may be implemented based on the first catalyst composition and the second catalyst composition being provided separately or being provided in combination. For example, in embodiments the first catalyst composition and the second catalyst composition may be provided separately within the same reactor, such as in separate layers, or they may be provided within separate reactors. In alternative embodiments, however, the first catalyst composition and the second catalyst composition may be mixed together There may be a single reactor bed where the catalyst is a mixed packed catalyst comprising the first catalyst composition and the second catalyst composition. It will be understood that when the first catalyst composition and the second catalyst composition are mixed together, the intermediate product does not undergo one or more fractionating steps to provide a fractionated intermediate product. The feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide will contact the first catalyst composition, and provide an intermediate product comprising olefins, and the intermediate product will contact the second catalyst composition, and will form a product comprising one or more alkanes

[0087] The method of the disclosure can be carried out in any suitable reactor. Fluidised bed reactors, fixed bed reactors, slurry bed reactors, and moving bed reactors are all examples of reactors that can be used.

[0088] In some embodiments, the feedstock is contacted with the first catalyst composition in a fixed bed reactor. In some embodiments, the intermediate product is contacted with the second catalyst composition in a fixed bed reactor. In some embodiments, the first and second catalyst compositions are in the same fixed reactor. In some embodiments, the feedstock is contacted with the first catalyst composition in a first fixed bed to provide an intermediate product which is subsequently contacted with the second catalyst composition in a second fixed bed in the same reactor.

[0089] In another embodiment, the first and second catalyst composition are packed into the same fixed bed. In this embodiment, the feedstock is contacted with the first catalyst composition in a fixed bed to provide an intermediate product which is subsequently contacted with the second catalyst composition in the same fixed bed in the same reactor.

[0090] In another embodiment, the first and second catalyst compositions are in separate reactors. In some embodiments, the feedstock is contacted with the first catalyst composition in a first fixed bed reactor and the intermediate product is contacted with the second catalyst composition in a second fixed bed reactor. In some embodiments, the intermediate product provided in the first fixed bed reactor is fed directly to the second fixed bed reactor. In another embodiment, the intermediate product provided in the first fixed bed reactor is subjected to one or more fractionating steps to provide a fractionated intermediate product which is fed to the second fixed bed reactor.

[0091] In some embodiments, the feedstock is contacted with the first catalyst composition at a temperature between at least about 200°C, suitably at least about 250°C.

[0092] In some embodiments, the feedstock is contacted with the first catalyst composition at a temperature of about 200°C to about 500°C, or about 200°C to about 350°C, suitably at about 300°C. In another embodiment, the feedstock is contacted with the first catalyst composition in a first reactor at a temperature of about 200°C to about 500°C, suitably at about 200°C, 250°C, 300°C or about 350°C.

[0093] In some embodiments, the feedstock is contacted with the first catalyst composition at a pressure of between about 1 and about 30 bar, or about 1 to about 20 bar, or about 1 to about 10 bar.

[0094] In some embodiments, the intermediate product is contacted with the second catalyst composition at a temperature of at least about 200°C, suitably at least about 250°C.

[0095] In another embodiment, the intermediate product is contacted with the second catalyst composition at a temperature of about 200°C to about 500°C, or about 200°C to about 350°C, suitably at about 300°C. In another embodiment, the intermediate product is contacted with the second catalyst composition in a second reactor at a temperature of about 200°C to about 500°C, suitably at about 200°C, 250°C, 300°C or 350°C.

[0096] In some embodiments, the intermediate product is contacted with the second catalyst composition at a pressure of between about 1 and about 30 bar, or about 1 to about 20 bar, or about 1 to about 10 bar.

[0097] In some embodiments, the intermediate product is subjected to one or more fractionating steps before being contacted with the second catalyst composition. In some embodiments, the one or more fractionating steps are selected from a distillation, a condensation and a phase separation.

[0098] In some embodiments, the method further comprises subjecting the product comprising one or more alkanes to one or more fractionating steps. In some embodiments, the one or more fractionating steps are selectedfrom a distillation, a condensation and a phase separation. For example, liquid phase products may be separated from gas phase products.

[0099] In some embodiments, the product comprises gaseous alkanes and the method further comprises subjecting said gaseous alkanes to a reforming process. Suitably, the gaseous alkanes comprise methane and the reforming step is a methane reforming process. The skilled person would be familiar with hydrocarbon reforming, in particular methane reforming, and would understand that this could be either a dry reforming or a steam reforming process. Suitably, the reformate is recycled as a component of the initial feedstock.First Catalyst Composition

[0100] The first catalyst composition comprises (i) an iron species, (ii) an alkali metal species, and (iii) a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species and a copper species.

[0101] In some embodiments, the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, and a copper species.

[0102] In some embodiments, the iron species is selected from elemental iron, an iron oxide, an iron carbide, an iron boride, an iron silicide and an iron hydride, or a combination thereof. Suitably, the iron species is selected from an iron oxide, elemental iron, an iron carbide or a combination thereof. More suitably, the iron species is an iron oxide and / or carbide. In another embodiment, the iron species is an iron oxide, suitably FciO i. Fe2C>3 or FeO.

[0103] In some embodiments, the first catalyst composition comprises from about 5 to about 90 wt.% iron. Suitably, the catalyst comprises about 10 to about 90 wt. % of iron. Suitably, from about 15 to about 90 wt. % of iron, more suitably from about 20 to about 90 wt. % of iron, more suitably from about 25 to about 90 wt. % of iron, more suitably from about 30 to about 90 wt. % of iron, more suitably from about 40 to about 90 wt. % of iron.

[0104] More suitably the first catalyst composition comprises about 50 wt. % of iron or more, or about 60 wt. % of iron or more; more suitably from about 50 to about 90 wt. % of iron, more suitably from about 60 to about 90 wt. % of iron.

[0105] In another embodiment, the first catalyst composition comprises from about 5 to about 80 wt.% iron. Suitably, the catalyst comprises about 10 to about 80 wt. % of iron. Suitably, from about 15 to about 80 wt. % of iron, more suitably from about 20 to about 80 wt. % of iron, more suitably from about 25 to about 80 wt. % of iron, more suitably from about 30 to about 80 wt. % of iron, more suitably from about 40 to about 80 wt. % of iron. More suitably, the first catalyst composition comprises from about 50 to about 80 wt. % of iron, more suitably from about 60 to about 80 wt. % of iron.

[0106] In another embodiment, the first catalyst composition comprises from about 5 to about 80 wt.% iron. Suitably, the catalyst comprises about 10 to about 70 wt. % of iron. Suitably, from about 15 to about 70 wt. % of iron, more suitably from about 20 to about 70 wt. % of iron, more suitably from about 25 to about 70 wt. % of iron, more suitably from about 30 to about 70 wt. % of iron, more suitably from about 40 to about 70 wt. % of iron. More suitably, the first catalyst composition comprises from about 50 to about 70 wt. % of iron, e.g. from about 60 to about 70 wt. % of iron.

[0107] In some embodiments, the alkali metal is selected from potassium, sodium, lithium or caesium. Accordingly, the first catalyst composition may comprise a potassium, sodium, lithium or caesium species, suchas an oxide thereof. In one embodiment, the alkali metal species is a potassium or sodium or caesium species. Suitably, the alkali metal species is a potassium or sodium species.

[0108] In some embodiments, the first catalyst composition comprises from about 0.5 to about 30 wt. % of alkali metal. Suitably, about 0.5 to about 25 wt. % of alkali metal. Suitably, from about 0.5 to about 20 wt. % of alkali metal, more suitably from about 0.5 to about 15 wt. % of alkali metal, more suitably from about 0.5 to about 10 wt. % of alkali metal, more suitably from about 0.5 to about 8 wt. % of alkali metal.

[0109] In another embodiment, the first catalyst composition comprises from about 1 to about 30 wt. % of alkali metal. Suitably from about 1 to about 25 wt. % of alkali metal. Suitably, from about 1 to about 20 wt. % of alkali metal, more suitably from about 1 to about 15 wt. % of alkali metal, more suitably from about 1 to about 10 wt. % of alkali metal, more suitably from about 1 to about 8 wt. % of alkali metal.

[0110] In another embodiment, the first catalyst composition comprises from about 3 to about 30 wt. % of alkali metal. Suitably from about 3 to about 25 wt. % of alkali metal. Suitably, from about 3 to about 20 wt. % of alkali metal, more suitably from about 3 to about 15 wt. % of alkali metal, more suitably from about 3 to about 10 wt. % of alkali metal, more suitably from about 3 to about 8 wt. % of alkali metal.

[0111] In some embodiments, the further transition metal is selected from one or more of a manganese species, a cobalt species, a zinc species and a copper species.

[0112] In some embodiments, the further transition metal is selected from one or more of a manganese or a cobalt species. In some embodiments, the first catalyst composition comprises both a manganese and a cobalt species.

[0113] In some embodiments, the manganese species is selected from elemental manganese, a manganese oxide, a manganese carbide, a manganese boride, a manganese silicide and a manganese hydride. Suitably, the manganese species is selected from elemental manganese, a manganese oxide and a manganese carbide. Suitably, the manganese species is selected from a manganese oxide, elemental manganese, or a combination thereof. More suitably, the manganese species is a manganese oxide.

[0114] In some embodiments, the first catalyst composition comprises from about 0.5 to about 30 wt. % of manganese. Suitably, about 0.5 to about 25 wt. % of manganese. Suitably, from about 0.5 to about 20 wt. % of manganese, more suitably from about 0.5 to about 15 wt. % of manganese, more suitably from about 0.5 to about 10 wt. % of manganese, more suitably from about 0.5 to about 6 wt. % of manganese.

[0115] In another embodiment, the first catalyst composition comprises from about 3 to about 30 wt. % of manganese. Suitably from about 3 to about 25 wt. % of manganese. Suitably, from about 3 to about 20 wt. % of manganese, more suitably from about 3 to about 15 wt. % of manganese, more suitably from about 3 to about 10 wt. % of manganese, more suitably from about 3 to about 6 wt. % of manganese.

[0116] In another embodiment, the first catalyst composition comprises from about 5 to about 30 wt. % of manganese. Suitably from about 5 to about 25 wt. % of manganese. Suitably, from about 5 to about 20 wt. % of manganese, more suitably from about 5 to about 15 wt. % of manganese, more suitably from about 5 to about 10 wt. % of manganese.

[0117] In some embodiments, the cobalt species is selected from elemental cobalt, a cobalt oxide, a cobalt carbide, a cobalt boride, a cobalt silicide and a cobalt hydride. Suitably, the cobalt species is selected from elemental cobalt, a cobalt oxide and a cobalt carbide. Suitably, the cobalt species is a cobalt oxide.

[0118] In some embodiments, the first catalyst composition comprises from about 0.5 to about 10 wt.% of a cobalt species. Suitably, about 0.5 to about 8 wt. % of a cobalt species. Suitably, about 0.5 to about 5 wt. % of a cobalt species. Suitably, about 0.5 to about 3 wt. % of a cobalt species.

[0119] In another embodiment, the first catalyst composition comprises from about 1 to about 10 wt.% of a cobalt species. Suitably, about 1 to about 8 wt. % of a cobalt species. Suitably, about 1 to about 5 wt. % of a cobalt species. Suitably, about 1 to about 3 wt. % of a cobalt species.

[0120] In some embodiments, the further transition metal is a copper species.

[0121] In some embodiments, the copper species is selected from elemental copper, a copper oxide, a copper carbide, a copper boride, a copper silicide and a copper hydride. Suitably, the copper species is selected from elemental copper, a copper oxide and a copper carbide. Suitably, the copper species is selected from a copper oxide, elemental copper, or a combination thereof. More suitably, the copper species is a copper oxide.

[0122] In some embodiments, the first catalyst composition comprises from about 0.5 to about 30 wt. % of copper. Suitably, about 0.5 to about 25 wt. % of copper. Suitably, from about 0.5 to about 20 wt. % of copper, more suitably from about 0.5 to about 15 wt. % of copper, more suitably from about 0.5 to about 10 wt. % of copper, more suitably from about 0.5 to about 6 wt. % of copper.

[0123] In another embodiment, the first catalyst composition comprises from about 3 to about 30 wt. % of copper. Suitably from about 3 to about 25 wt. % of copper. Suitably, from about 3 to about 20 wt. % of copper, more suitably from about 3 to about 15 wt. % of copper, more suitably from about 3 to about 10 wt. % of copper, more suitably from about 3 to about 6 wt. % of copper.

[0124] In another embodiment, the first catalyst composition comprises from about 5 to about 30 wt. % of copper. Suitably from about 5 to about 25 wt. % of copper. Suitably, from about 5 to about 20 wt. % of copper, more suitably from about 5 to about 15 wt. % of copper, more suitably from about 5 to about 10 wt. % of copper.

[0125] In some embodiments, the further transition metal is a zinc species.

[0126] In some embodiments, the zinc species is selected from elemental zinc, a zinc oxide, a zinc carbide, a zinc boride, a zinc silicide and a zinc hydride. Suitably, the zinc species is selected from elemental zinc, a zinc oxide and a zinc carbide. Suitably, the zinc species is selected from a zinc oxide, elemental zinc, or a combination thereof. More suitably, the zinc species is a zinc oxide.

[0127] In some embodiments, the first catalyst composition comprises from about 0.5 to about 30 wt. % of zinc. Suitably, about 0.5 to about 25 wt. % of zinc. Suitably, from about 0.5 to about 20 wt. % of zinc, more suitably from about 0.5 to about 15 wt. % of zinc, more suitably from about 0.5 to about 10 wt. % of zinc, more suitably from about 0.5 to about 6 wt. % of zinc.

[0128] In another embodiment, the first catalyst composition comprises from about 3 to about 30 wt. % of zinc. Suitably from about 3 to about 25 wt. % of zinc. Suitably, from about 3 to about 20 wt. % of zinc, more suitably from about 3 to about 15 wt. % of zinc, more suitably from about 3 to about 10 wt. % of zinc, more suitably from about 3 to about 6 wt. % of zinc.

[0129] In another embodiment, the first catalyst composition comprises from about 5 to about 30 wt. % of zinc. Suitably from about 5 to about 25 wt. % of zinc. Suitably, from about 5 to about 20 wt. % of zinc, more suitably from about 5 to about 15 wt. % of zinc, more suitably from about 5 to about 10 wt. % of zinc.

[0130] In addition to the (i) iron species, (ii) an alkali metal species, and (iii) further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species and acopper species, in some embodiments, the first catalyst composition also comprises (iv) at least one further metal species. In some embodiments, the further metal species is a transition metal species. Suitably, the further metal species is a transitional metal or oxide thereof. It may for example be selected from: a manganese species, a cobalt species, a zinc species, a copper species and a zirconium species.

[0131] In some embodiments, the first catalyst composition comprises from about 0.5 to about 10 wt.% of a further metal species. Suitably, about 0.5 to about 8 wt. % of a further metal species. Suitably, about 0.5 to about 5 wt. % of a further metal species. Suitably, about 0.5 to about 3 wt. % of a further metal species.

[0132] In another embodiment, the first catalyst composition comprises from about 1 to about 10 wt.% of a further metal species. Suitably, about 1 to about 8 wt. % of a further metal species. Suitably, about 1 to about 5 wt. % of a further metal species. Suitably, about 1 to about 3 wt. % of a further metal species.

[0133] In one embodiment, the first catalyst composition comprises two or more further transition metal species, which may for example be selected from: a manganese species, a cobalt species, a zinc species, a copper species and a zirconium species.

[0134] The alkali metal species (ii), and the further transition metal species (iii), and any optional further metal species (iv), can be referred to as “promoters”. In some embodiments, the first catalyst composition comprises from about 50 to about 90wt% of iron species and from about 10 to about 50wt% promoters; such as from about 60 to about 90wt% of iron species and from about 10 to about 40wt% promoters. This can assist with good dispersion of the promoters.

[0135] In some embodiments, the first catalyst composition comprises an iron species, a manganese species, at least one further transition metal species selected from cobalt, zinc and copper species, and an alkali metal species. In some embodiments, the alkali metal species can be a potassium species.

[0136] In another embodiment, the first catalyst composition comprises an iron species, a manganese species, a cobalt species, and an alkali metal species. Suitably, the alkali metal species is a potassium species.

[0137] In some embodiments, the first catalyst composition comprises an iron species, a copper species, and an alkali metal species. Suitably, the alkali metal species is a potassium species.

[0138] In some embodiments, the first catalyst composition comprises an iron species, a zinc species, and an alkali metal species. Suitably, the alkali metal species is a potassium species. In another embodiment, the first catalyst composition comprises iron or an oxide or carbide thereof, a manganese or an oxide thereof, cobalt or an oxide thereof, and an alkali metal, a carbonate thereof or an oxide thereof. Suitably, the alkali metal is potassium, potassium carbonate or an oxide thereof.

[0139] In some embodiments, the molar ratio of iron to manganese in the first catalyst composition is about 100:1 to about 4:1, more suitably about 100:1 to about 5:1, more suitably about 20:1 to about 5:1, more suitably about 10:1. This ratio has been found to be particularly beneficial in terms of good dispersion of the manganese.

[0140] In some embodiments, the molar ratio of iron to alkali metal in the first catalyst composition is about 100:1 to about 4:1, more suitably about 100:1 to about 5:1, more suitably about 20:1 to about 5:1, more suitably about 10:1. Suitably, the alkali metal is potassium. This ratio has been found to be particularly beneficial in terms of good dispersion of the alkali metal.

[0141] In some embodiments, the molar ratio of iron to further transition metal (e.g. cobalt) in the first catalyst composition is about 100:1 to about 10:1, more suitably about 80:1 to about 20:1, more suitably about 75:1 toabout 20:1, more suitably about 50:1. This ratio has been found to be particularly beneficial in terms of good dispersion of the further transition metal.

[0142] In some embodiments, the molar ratio of iron to copper in the first catalyst composition is about 100:1 to about 4:1, more suitably about 100:1 to about 5:1, more suitably about 20:1 to about 5:1, more suitably about 10:1.

[0143] In some embodiments, the molar ratio of iron to zinc in the first catalyst composition is about 100:1 to about 4:1, more suitably about 100:1 to about 5:1, more suitably about 20:1 to about 5:1, more suitably about 10:1.

[0144] In some embodiments, the first catalyst composition comprises an iron species, a manganese species, a cobalt species, and a potassium species. Suitably in a molar ratio of Fe: Mn: Co: K of 100:(10 to 50):(0.5 to 5): (2 to 10). This ratio has been found to be beneficial in terms of good dispersion of the promoters.

[0145] In some embodiments, the first catalyst composition comprises iron or an oxide or carbide thereof, manganese or an oxide thereof, cobalt or an oxide thereof, and potassium or an oxide thereof. Suitably, in a molar ratio of Fe: Mn: Co: K of 100:10:2:10. This ratio has been found to be particularly beneficial in terms of good dispersion of the promoters.

[0146] In some embodiments, the first catalyst composition further comprises a carbon species. Suitably the carbon species is selected from amorphous carbon, active carbon, graphite, or a metal carbide.

[0147] Some specific examples of the first catalyst composition and their molar ratios include: Fe: Mn: Co: K 100:10:2:10; Fe: Mn: K 100:10:10; Fe: Cu: K 100:10:10; Fe: Zn: K 100:10:10; Fe: Zr: K 100:10:10; Fe-Cu: Co: K 100:10:2:10Fe-Zn: Co: K 100:10:2:10; Fe: Zr: Co: K 100:10:2:10; Fe: Zn: Zr: K 100:10:2:10; Fe: Cn: Zr: K 100:10:2:10; Fe: Zn: Zr: Co: K 100:10:2:2:10; and variants thereof wherein the K is replaced by Na and / or Cs.

[0148] In some embodiments, the first catalyst composition comprises about 0.1 wt.% to about 10 wt. % of the carbon species. Suitably, about 0.1 to about 8 wt. % of the carbon species. Suitably, about 0.1 wt.% to about 5 wt. % of the carbon species. In another embodiment, the first catalyst composition comprises about 0.5 wt.% to about 10 wt. % of the carbon species. Suitably, about 0.5 wt.% to about 8 wt. % of the carbon species. Suitably, about 0.5 to about 5 wt. % of the carbon species. In another embodiment, the first catalyst composition comprises about 2 wt.% to about 10 wt. % of the carbon species. Suitably, about 2 to about 8 wt. % of the carbon species. Suitably, about 2 wt.% to about 5 wt. % of the carbon species.

[0149] In one embodiment, the first catalyst is provided in bulk form, i.e. it is unsupported. It has surprisingly been found that by using the first catalyst in bulk form, superior selectivity toward liquid hydrocarbons is exhibited, particularly in the jet-fuel range (C8-C16). By using the first catalyst in bulk form, there is also higher activity than when the first catalyst is used in supported form.

[0150] Unexpectedly, the use of a first catalyst composition that comprises an iron species, a manganese species, at least one further transition metal species selected from cobalt, zinc and copper species, and an alkali metal species (such as potassium), has been found to have a relatively high surface area when provided in bulk form. This helps achieve better dispersion of the promoters, and facilitates iron carburisation, since Fe-FT is the main active phase in Fischer-Tropsch synthesis.

[0151] It may be that, prior to use, the first catalyst composition is activated. Activation may involve reduction of the catalyst composition. Activation may, in embodiments, be achieved by passing a H2and CO gas mixture(“syngas”) over or through the catalyst composition. For example, it may be activated by being contacted with syngas (H2: CO = 2:1) at atmospheric pressure.Second Catalyst Composition

[0152] The second catalyst composition comprises a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

[0153] The second catalyst composition suitably comprises a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, and a nickel species.

[0154] It is preferred that the metal species is selected from one or more of a platinum, a palladium, and a nickel species. The use of these metal catalysts in combination with a solid acid catalyst is beneficial, because they catalyse the hydrogenation of alkenes to alkanes, which is a key desired reaction in the present invention.

[0155] In one embodiment, no further metal species is present in an amount of more than lwt%. In one embodiment, no further metal species is present.

[0156] In some embodiments, the second catalyst composition comprises only one metal species, wherein the metal species is selected from a platinum species, a palladium species, and a nickel species. In alternative embodiments, the second catalyst composition comprises more than one metal species, wherein each metal species that is present is selected from the group consisting of: platinum species, palladium species, and nickel species.

[0157] In some embodiments, the metal species is a platinum species, suitably elemental platinum or a platinum oxide.

[0158] In some embodiments, the metal species is a nickel species, suitably elemental nickel, a nickel phosphide or a nickel oxide.

[0159] In some embodiments, the metal species is a palladium species, suitably elemental palladium or a palladium oxide.

[0160] In some embodiments, the metal species is a platinum species and a palladium species.

[0161] In some embodiments, the second catalyst composition comprises a further metal species, suitably selected from a silver species.

[0162] Solid acid catalysts are well known to the skilled person.

[0163] In some embodiments, the solid acid catalyst is selected from aluminosilicate catalysts (such as zeolites), transition metal oxides such as titania, zirconia, and niobia, SnO2, WO2, as well as aluminium oxide, and sulfated metal oxides.

[0164] In some embodiments, the solid acid is selected from a transition metal oxide or an alumina silicate, such as a zeolite.

[0165] In some embodiments, the transition metal oxide is selected from the group consisting of an aluminium oxide, tungsten oxide, niobium oxide, zinc oxide, zirconium oxide, and a titanium oxide. Suitably, the transition metal oxide is an aluminium oxide solid acid catalyst, for example A12C>3.

[0166] In some embodiments, the zeolite is selected from a hydrogen zeolite (zeolite in protonated form), an acidic aluminosilicate zeolite or an acidic silicon aluminium phosphate (SAPO) zeolite.

[0167] As the skilled person will appreciate, aluminosilicate zeolites comprise SiO₄ and AlO₄ tetrahedra, and each AIO4 tetrahedron, with its trivalent aluminium, bears an extra negative charge, which is balanced by mono-, bi- or tri- valent cations. Such zeolites are often prepared in their sodium form. However, surface acidity can be generated (to produce an acidic zeolite) by replacing Na+by H+through ammonium ion exchange. Protons can beintroduced into the structure through ion-exchanged forms, hydrolysis of water, or hydration of cations or reduction of cations to a lower valency state. In the case of hydrogen zeolites, protons associated with the negatively charged framework aluminium are the source of Bronsted acid activity and a linear relationship between catalytic activity and the concentration of protonic sites associated with framework aluminium has been demonstrated.

[0168] The skilled person is well aware of zeolites, including Zeolite Socony Mobil (ZSM) and Mobil Composition of Matter (MCM). Examples include ZSM-5, ZSM-11, ZSM-22, ZSM-23. ZSM zeolites may be provided in protonated form, denoted “HZSM”. For example, HZSM-5, HZSM-11, HZSM-22, HZSM-23.

[0169] In some embodiments, the solid acid catalyst comprises, essentially consists of, or consists of a zeolite, optionally in protonated form. It may be a ZSM or HZSM zeolite. The zeolite may have a Si: Al ratio of, for example, from about 20 to about 90, for instance from about 20 to about 80, for instance from about 20 to about 60, or for example from about 30 to about 60, or from about 40 to about 60.

[0170] In one embodiment, the solid acid catalyst comprises, essentially consists of, or consists of acidic silicon aluminium phosphate (SAPO) zeolites, for instance SAPO-11 or S APO-5.

[0171] In some embodiments, the solid acid catalyst comprises, essentially consists of, or consists of a zeolite, suitably selected from the group consisting of HZSM-11, HZSM-22, HZSM-23, HZSM-35, HZSM-48, HMCM-22, SAPO-11 and H-Beta zeolite. In some embodiments, the solid acid catalyst comprises, essentially consists of, or consists of HZSM-5. In some embodiments, the solid acid catalyst comprises, essentially consists of, or consists of S APO-5.

[0172] In another embodiment, the solid acid comprises, essentially consists of, or consists of a zeolite selected from an acidic aluminosilicate zeolite having the general formula (I):[M^ AlOz-MS M] (I)whereinM is H+or M is two or more different cations, one of which is H+;n is the valance of the cation; andthe Si: Al ratio y / x is from 1 to 300.

[0173] In some embodiments, the Si: Al ratio y / x may for instance be from about 20 to about 90, for instance be from about 20 to about 80, for instance from about 20 to about 60, or for example from about 30 to about 60, or from about 40 to about 60. In some embodiments, the Si: Al ratio y / x is about 50.

[0174] In some embodiments, when M is two or more different cations, one of which is H+, the charge ratio of H+to the other cations M is typically equal to or greater than 1. In other words, at least half of the positive charges arising from all the M”+cations are typically due to protons.

[0175] In some embodiments, the zeolite has a Si: Al ratio of from about 2 to 200, for instance from about 5 to about 100, for instance from about 10 to about 80, or for example from about 10 to about 60.

[0176] In some embodiments, the zeolite has a Si: Al ratio of from about 10 to 90, for instance from about 10 to about 80, for instance from about 10 to about 60, or for example from about 20 to about 60, or about 30 to about 60, or from about 40 to about 60.

[0177] In some embodiments, the solid acid catalyst is H-ZSM-5 zeolite. In some embodiments, the solid acid catalyst is H-ZSM-5 zeolite with an Si: Al ratio of from 20 to 90, for instance from about 20 to about 80, for instance from about 20 to about 60, or for example from about 30 to about 60, or from about 40 to about 60. Insome embodiments, the solid acid is H-ZSM-5 zeolite with an Si / Al ratio of about 50 to about 60. Such H-ZSM-5 zeolites are commercially available from ZEOLYST international Company.

[0178] In some embodiments, the solid acid catalyst is a mesopororus solid acid catalyst. The meaning of the term “mesoporous” in this context is well known in the art. For instance, the IUPAC Goldbook defines mesoporous as meaning pores of intermediate size between microporous and macroporous, in particular with widths between 2 nm and 0.05 pm. Pore size can be assessed by gas adsorption, e.g. ISO 15901-2:2006(E).

[0179] In some embodiments, the solid acid comprises or essentially consists of or consists of a crystalline, mesoporous solid acid.

[0180] In some embodiments, the solid acid comprises, or essentially consists of, or consists of a mesoporous solid acid. In another embodiment, the solid acid comprises, essentially consists of or consists of a non-ordered mesoporous solid acid. In another embodiment, the solid acid comprises, essentially consists of or consists of an ordered mesoporous solid acid.

[0181] In some embodiments, the mesoporous solid acid may be any of the solid acid catalyst materials referred to above in mesoporous form. In some embodiments, the solid acid catalyst comprises a mesoporous zeolite, suitably a mesoporous H-zeolite (protonated zeolite).

[0182] In another embodiment, the solid acid comprises or essentially consists of or consists of a crystalline nano- or microporous solid acid.

[0183] In some embodiments, the second catalyst composition comprises a mesoporous solid acid catalyst selected from a mesoporous acidic aluminosilicate zeolite or a mesoporous acidic silicon aluminium phosphate (SAPO) zeolite.

[0184] In some embodiments, the second catalyst composition comprises a solid catalyst that is an acidic silicon aluminium phosphate (SAPO) zeolite, AI2O3 or a H-ZSM zeolite. In another embodiment, the second catalyst composition comprises a solid catalyst that is SAPO- 11 zeolite or AI2O3.

[0185] In some embodiments, the metal species is supported on the solid acid catalyst.

[0186] In some embodiments, the second catalyst composition essentially consists of or consists of the metal species and the solid acid catalyst.

[0187] In some embodiments, the wt.% of metal species to solid acid is about 0.1 wt.% to about 10 wt.%. It is preferred that the metal species is present at a level of about 0.1 wt.% to about 10 wt.% in the second catalyst composition, in order to drive catalysis of the desired hydrogenation reaction of alkenes to alkanes. The level can be expressed as the amount of metal species with respect to the amount of solid acid, as a weight percentage.

[0188] Suitably, the wt.% of metal to solid acid is about 0.1 wt.% to about 5 wt.%; suitably about 0.1 wt.% to about 3 wt.%, about 0.1 wt.% to about 2 wt.%.

[0189] In another embodiment, the wt.% of metal species to solid acid is about 0.1 wt.% to about 10 wt.%. Suitably, the wt.% of metal to solid acid is about 0.5 wt.% to about 5 wt.%; suitably about 0.5 wt.% to about 3 wt.%, about 0.5 wt.% to about 2 wt.%.

[0190] In another embodiment, the wt.% of metal species to solid acid is about 1 wt.%. For example, there may be 1g of metal species and 100g of solid acid.

[0191] In some embodiments, the second catalyst composition comprises or essentially consists of or consists of one of: Pt / SAPO-11, Pt / Beta-zeolite, Pt / HMCM-22, Pt / HZSM-22, Pt / HZSM-48, Pt / HZSM-11, Pt / HZSM-23,Pt / HZSM-35, Pt / Al₂O₃, Pd / Al₂O₃, Pd / SAPO-11 and Ni / SAPO-11. Suitably, in such embodiments, the wt.% of metal species to solid acid is about 0.5 wt.% to about 2 wt.%, more suitably about 1 wt.%.

[0192] In some embodiments, the second catalyst composition comprises or essentially consists of or consists of one of Pt / SAPO-11, Pt / Al₂O₃, or Ni / SAPO-11. Suitably, in such embodiments, the wt.% of metal species to solid acid is about 0.5 wt.% to about 2 wt.%, more suitably about 1 wt.%.

[0193] It may be that, prior to use, the second catalyst composition is activated. Activation may involve reduction of the catalyst composition. Activation may, in embodiments, be achieved by passing a H2and CO gas mixture (“syngas”) over or through the catalyst composition. For example, it may be activated by being contacted with syngas (H2: CO = 2: 1) at atmospheric pressure. Activation may, in other embodiments, be achieved by passing a H2and N2gas mixture over or through the catalyst composition. For example, it may be activated by being reduced with 10% H2 / N2at atmospheric pressure.Catalyst Combination

[0194] In another aspect, the present disclosure provides a catalyst combination comprising a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species and a copper species; and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

[0195] In one embodiment, the catalyst combination comprises a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, and a copper species; and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

[0196] As used herein, combination refers to a physical combination of the compositions, either in the same composition or as separate compositions within another physical entity, such as a composition, a catalyst bed, reactor or system. Consequently, in the catalyst combination disclosed herein the first and second catalyst compositions may be arranged sequentially, separately or in admixture with respect to each other.

[0197] In some embodiments, the catalyst combination is a sequential combination, for instance when both catalyst composition are combined in the same reactor, the combination may be arranged sequentially, for example in separate catalyst beds.

[0198] In another embodiment, the catalyst combination is an admixture of the first catalyst composition and the second catalyst composition. For instance, when both catalyst compositions are combined in the same reactor, the compositions may be arranged in admixture in a single catalyst bed.

[0199] In another embodiment, the catalyst combination is a separate combination of the compositions. For instance, when the catalyst compositions are in separate reactors within the same system.

[0200] The first catalyst composition is described further above and may be according to any of the abovedescribed embodiments. Similarly, the second catalyst composition is described further above and may be according to any of the above-described embodiments.

[0201] In some embodiments, the catalyst combination comprises a first catalyst composition comprising an iron species, a manganese species, a cobalt species, and an alkali metal species, and a second catalyst compositioncomprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, and a nickel species.

[0202] In some embodiments, the catalyst combination comprises a first catalyst composition comprising an iron species, a manganese species, a cobalt species, and an alkali metal species, wherein the first catalyst comprises about 50 wt. % or more of iron, such as about 50 to about 90 wt. % of iron, and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, and a nickel species. In some embodiments, it may be that the second catalyst composition only comprises one metal species, wherein the metal species is selected from a platinum species, a palladium species, and a nickel species; or it may be that the second catalyst composition more than one metal species, wherein each metal species that is present is selected from the group consisting of: platinum species, palladium species, and nickel species.

[0203] In some embodiments, the catalyst combination comprises a first catalyst comprising an iron species, a manganese species, a cobalt species, and an alkali metal species and a second catalyst composition that is selected from one of Pt / SAPO-11, Pt / Beta-zeolite, Pt / HMCM-22, Pt / HZSM-22, Pt / HZSM-48, Pt / HZSM-11, Pt / HZSM-23, Pt / HZSM-35, Pt / Al₂O₃, Pd / Al₂O₃, Pd / SAPO-11 and Ni / SAPO-11.

[0204] In another embodiment, the catalyst combination comprises a first catalyst comprising an iron species, a manganese species, a cobalt species, and an alkali metal species and a second catalyst composition is selected from Pt / SAPO-11, Pt / Al₂O₃ or Ni / SAPO-11.

[0205] In embodiments, the first catalyst composition and the second catalyst composition may be in a weight ratio of from 10:1 to 1:10, such as from 5:1 to 1:5, or from 5:1 to 1:2, or from 3:1 to 1:1.

[0206] In another aspect the present disclosure provides the use of a catalyst combination as described in any of the aspects or embodiments herein for preparing a liquid product comprising alkanes.

[0207] In another aspect the present disclosure provides a method for preparing a liquid product comprising alkanes using a catalyst combination as described in any of the aspects or embodiments. Suitably in the method the liquid product comprising alkanes is prepared from a gaseous mixture comprising hydrogen and carbon dioxide, or a gaseous mixture comprising hydrogen and carbon monoxide, or a gaseous mixture comprising hydrogen, carbon monoxide and carbon dioxide.

[0208] Suitably the liquid product comprises C5+ alkanes, more suitably Cs-ie alkanes. In some embodiments, the liquid product is suitable for use as a fuel or a component thereof, suitably an aviation fuel or a component thereof. In some embodiments, the liquid product is a suitable paraffinic blend component of jet fuel (e.g. Jet A and Jet A-l).System

[0209] In another aspect, the present disclosure provides a system for the production of a product comprising one or more alkanes comprising one or more reactors; a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species and a copper species; and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species; wherein the first and second catalyst composition are contained in the one or more reactors.

[0210] The product comprising one or more alkanes is described further above and may be according to any of the above-described embodiments.

[0211] The first catalyst composition is described further above and may be according to any of the abovedescribed embodiments. Similarly, the second catalyst composition is described further above and may be according to any of the above-described embodiments.

[0212] In some embodiments, the system comprises one reactor. Accordingly, in this embodiment, said one reactor contains both the first catalyst composition and the second catalyst composition. In some embodiments, the reactor contains the catalyst combination of any of the above-mentioned aspects or embodiments.

[0213] In some embodiments, one reactor comprises the first catalyst composition and the second catalyst composition in separate fixed beds within said reactor. Suitably, the catalyst compositions are arranged sequentially within the reactor. Suitably, the reactor comprises one or more inlets for supplying one or feedstock gases and the first catalyst composition is arranged within said reactor such that said composition is contacted first by the feedstock gases. Suitably, the second catalyst composition is arranged downstream to the first catalyst composition within the reactor.

[0214] In another embodiment, the first catalyst composition and the second catalyst composition are in the same fixed bed within said one reactor.

[0215] In some embodiments, the system further comprises one or more fractionating means. In some embodiments, the one or more fractionating means are selected from a hot trap, a cold trap or a gas-liquid separator.

[0216] In some embodiments, the reactor has an outlet with is coupled to at least one fractionating means.

[0217] In another embodiment, the system comprises two reactors. In some embodiments, a first reactor contains the first catalyst composition and a second reactor contains the second catalyst composition. In some embodiments, a first reactor is coupled to one or more feedstock gases and said reactor comprises the first catalyst composition. In some embodiments, the first reactor comprises one or more outlets, at least one of which is coupled, suitably directly, to the second reactor comprising the second catalyst composition.

[0218] The reactors may be coupled, for instance to each other, to the feedstock gases or to fractionating means, by means conventional in the art, such as piping or conduit.

[0219] In some embodiments, the second reactor comprises an outlet which is coupled to at least one fractionating means, suitably selected from a hot trap, a cold trap or a gas-liquid separator.

[0220] In another embodiment, the first reactor comprises an outlet which is coupled to at least one fractionating means, suitably selected from the group consisting of a hot trap, a cold trap and a gas-liquid separator. Suitably, in this embodiment, the second reactor has an inlet which is arranged to receive an input from the at least one fractionating means.

[0221] In some embodiments, the system is according to Figure 1. In Figure 1, a feedstock gas source

[0101] comprising one or more feedstock gas (e.g. carbon dioxide, carbon monoxide, hydrogen and / or nitrogen), is directly coupled to an inlet of a single reactor

[0102] comprising a first fixed catalyst bed comprising the first catalyst composition

[0103] arranged closest to the inlet such that it is contacted by the feedstock gases first, and a second fixed catalyst bed comprising the second catalyst composition

[0104] arranged downstream to the first fixed catalyst bed relative to the inlet.

[0222] In reactor

[0102] , the catalyst beds and feedstock gas are heated (e.g. 300°C) under pressure (e.g. 10 bar). The feedstock gas (e.g. carbon dioxide and / or carbon monoxide, and hydrogen) contact the first catalyst composition in a first fixed catalyst bed resulting in hydrogenation of the carbon dioxide and / or carbon monoxideto provide hydrocarbons, primarily olefins, as an intermediate product. The intermediate product subsequently contacts the second catalyst composition in the second fixed catalyst bed resulting in hydrogenation and / or isomerisation of the olefins in the intermediate product to corresponding paraffins.

[0223] The products of the reactor

[0102] exit via an outlet coupled with a hot trap

[0105] , In the hot trap the products are cooled to about 180°C and a heavy fraction condenses comprising mainly C20+ hydrocarbons. The other hydrocarbons and steam are condensed in the cold trap

[0106] , and the resulting hydrocarbons and water introduced to a separator

[0107] , the liquid hydrocarbons and water are separated from the gas products which include unconverted CO2 and H2, and by-products such as CO and light hydrocarbons. The gaseous fraction is sent to GC analysis or vent.

[0224] Another embodiment of the present system is illustrated in Figure 6. In Figure 6, a feedstock gas source

[0201] comprising one or more feedstock gas (e.g. carbon dioxide, carbon monoxide, hydrogen and / or nitrogen), is directly coupled to an inlet of a first reactor

[0202] comprising a fixed catalyst bed comprising the first catalyst composition

[0203] , Reactor

[0202] comprises an outlet directly coupled to an inlet of a second reactor

[0204] comprising a second fixed catalyst bed comprising the second catalyst composition

[0205] ,

[0225] In the first reactor

[0202] the catalyst bed

[0203] and feedstock gases are heated (e.g. 200°C or 300°C) under pressure (e.g. 10 bar). The feedstock gas (e.g. carbon dioxide and / or carbon monoxide, and hydrogen) contact the first catalyst composition in the fixed bed resulting in hydrogenation of the carbon dioxide and / or carbon monoxide to provide hydrocarbons, primarily olefins, as an intermediate product. The intermediate product is conveyed from the first reactor to the second reactor

[0204] , In the second reactor the intermediate product contacts the second catalyst composition

[0205] in a fixed bed resulting in hydrogenation and / or isomerisation of the olefins in the intermediate product to corresponding paraffins.

[0226] The products of the reactor

[0204] exit via an outlet coupled with a hot trap

[0206] , In the hot trap the products are cooled to about 180°C and a heavy fraction condenses comprising mainly C20+ hydrocarbons. The other hydrocarbons and steam are condensed in the cold trap

[0207] , and the resulting hydrocarbons and water introduced to a separator

[0208] , the liquid hydrocarbons and water are separated from the gas products which include unconverted CO2 and H2, and by-products such as CO and light hydrocarbons. The gaseous fraction is sent to GC analysis or vent.

[0227] Another embodiment of the present system is illustrated in Figure 7. In Figure 7, a feedstock gas source

[0301] comprising one or more feedstock gas (e.g. carbon dioxide, carbon monoxide, hydrogen and / or nitrogen), is directly coupled to an inlet of a first reactor

[0302] comprising a fixed catalyst bed comprising the first catalyst composition

[0303] ,

[0228] In the first reactor

[0302] the catalyst bed

[0303] and feedstock gases are heated (e.g. 300°C) under pressure (e.g. 10 bar). The feedstock gas (e.g. carbon dioxide and / or carbon monoxide, and hydrogen) contact the first catalyst composition in the fixed bed resulting in hydrogenation of the carbon dioxide and / or carbon monoxide to provide hydrocarbons, primarily olefins, as an intermediate product. The products of the reactor

[0302] exit via an outlet coupled with a hot trap

[0304] , In the hot trap the products are cooled to about 180°C and a heavy fraction condenses comprising mainly C20+ hydrocarbons. The other hydrocarbons and steam are condensed in the cold trap

[0305] , and the resulting hydrocarbons and water introduced to a separator

[0306] , the liquid hydrocarbons and water will be separated into two phases due to their different density. The water is collected from an outlet at the bottom of the separator

[0306] , whilst the liquid hydrocarbons is collected by an outlet

[0309] at relatively higherposition of the separator

[0306] , The gas products which include unconverted CO2 and H2, by products CO and light hydrocarbons will go to GC analysis or vent.

[0229] The liquid hydrocarbon outlet

[0309] is directly coupled to an inlet of a second reactor

[0307] comprising a second catalyst composition

[0308] , The fractionated intermediate product from separator

[0306] is conveyed to the second reactor

[0307] , In the second reactor the fractionated intermediate product contacts the second catalyst composition in a fixed catalyst bed

[0308] resulting in hydrogenation and / or isomerisation of the olefins in the fractionated intermediate product to corresponding paraffins.

[0230] Another embodiment of the present system is illustrated in Figure 8. In Figure 8, a feedstock gas source

[0401] comprising one or more feedstock gas (e.g. carbon dioxide, carbon monoxide, hydrogen and / or nitrogen), is directly coupled to an inlet of a first reactor

[0402] comprising a fixed catalyst bed comprising the first catalyst composition

[0403] arranged closest to the inlet such that it is contacted by the feedstock gases first, and a second fixed bed comprising a second catalyst composition

[0404] arranged downstream to the first fixed bed relative to the inlet.

[0231] In the first reactor

[0402] the catalyst beds

[0403]

[0404] and feedstock gases are heated (e.g. 300°C) under pressure (e.g. 10 bar). The feedstock gas (e.g. carbon dioxide and / or carbon monoxide, and hydrogen) contact the first catalyst composition in the fixed bed resulting in hydrogenation of the carbon dioxide and / or carbon monoxide to provide hydrocarbons, primarily olefins, as an intermediate product. The intermediate product subsequently contacts the second catalyst composition in the second fixed catalyst bed resulting in hydrogenation and / or isomerisation of the olefins in the intermediate product to corresponding paraffins. The products of the reactor

[0402] exit via an outlet coupled with a hot trap

[0405] , In the hot trap the products are cooled to about 180°C and a heavy fraction condenses comprising mainly C20+ hydrocarbons. The other hydrocarbons and steam are condensed in the cold trap

[0406] , and the resulting hydrocarbons and water introduced to a separator

[0407] , the liquid hydrocarbons and water are separated from the gas products. The gas products from separator

[0407] which include unconverted CO2 and H2, and by-products, such as CO and light hydrocarbons, will go to a reforming reactor

[0408] , with a hydrocarbon reforming catalyst bed

[0409] , The gas products, including light hydrocarbons and carbon dioxide contact the hydrocarbon reforming catalyst in fixed bed

[0409] resulting in the formation of carbon monoxide and hydrogen. The syngas enriched gaseous product

[0410] is then recycled to the first reactor

[0402] as feedstock. The reforming reactor

[0408] may optionally be supplied with a steam and / or O2co-feedstock of reforming reactor. The reforming can be steam reforming, dry reforming or partial oxidation of light alkanes.

[0232] The invention will now further be described by means of the following numbered clauses, which are not claims:1. A method for producing a product comprising one or more alkanes, said method comprising:contacting a feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide with a first catalyst composition, wherein the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species and a copper species (for example selected from one or more of a manganese species, a cobalt species, a zinc species and a copper species), to provide an intermediate product comprising olefins; optionally subjecting the intermediate product to one or more fractionating steps to provide a fractionated intermediate product; andcontacting said optionally fractionated intermediate product with a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.2. A method according to clause 1, wherein the alkanes are one or more saturated acyclic alkanes.3. A method according to clause 1 or 2, wherein the alkanes are C5+ alkanes, suitably C8-16 alkanes. 4. A method according to any one of the preceding clauses, wherein the product comprises at least about 90 wt.% of alkanes.5. A method according to any one of the preceding clauses, wherein the product comprises a liquid product that has a ratio of alkene:alkane of about 0.5 or less, or about 0.1 or less, such as about 0.05 or less, suitably about 0.01 or less.6. A method according to any one of the preceding clauses, wherein the feedstock is contacted with the first catalyst in a fixed bed reactor, and / or the intermediate product is contacted with the second catalyst in a fixed bed reactor.7. A method according to any one of the preceding clauses, wherein the feedstock is contacted with the first catalyst composition and intermediate product is contacted with the second catalyst composition in the same fixed bed reactor.8. A method according to any one of the preceding clauses, wherein the first and second catalyst composition are packed into a catalyst bed.9. A method according to clause 8, wherein the first and second catalyst composition are packed into the same catalyst bed.10. A method according to any one of clauses 1 to 6, wherein the feedstock is contacted with the first catalyst composition in a first fixed bed reactor and the intermediate product is contacted with the second catalyst composition in a second fixed bed reactor.11. A method according to any one of the preceding clauses, wherein the feedstock is contacted with the first catalyst composition at a temperature of about 200°C to about 500°C, suitably at about 300°C.12. A method according to any one of the preceding clauses, wherein the intermediate product is contacted with the first catalyst at a temperature of about 200°C to about 500°C, suitably at about 200°C to about 350°C, suitably at about 200°C to about 350°C.13. A method according to any one of the preceding clauses, wherein the method further comprises subjecting the product comprising one or more alkanes to one or more fractionating steps.14. A method according to any one of the preceding clauses, wherein the first catalyst composition comprises an iron species selected from an iron oxide, elemental iron, an iron carbide or a combination thereof.15. A method according to any one of the preceding clauses, wherein the first catalyst composition comprises about 50 to about 90 wt. % of iron.16. A method according to any one of the preceding clauses, wherein the first catalyst composition comprises a manganese species selected from a manganese oxide, elemental manganese, or a combination thereof.17. A method according to any one of the preceding clauses, wherein the first catalyst composition comprises about 3 to about 10 wt. % of manganese.18. A method according to any one of the preceding clauses, wherein the first catalyst composition about 3 to about 10 wt. % of an alkali metal species.19. A method according to any one of the preceding clauses, wherein the alkali metal species is selected from a sodium or potassium species, suitably a potassium species.20. A method according to any one of the preceding clauses, wherein the first catalyst composition comprises at least one further transition metal species.21. A method according to clause 20, wherein the first catalyst composition comprises about 0.5 to about 5 wt. % of the further transition metal species.22. A method according to clause 20 or 21, wherein the further transition metal species is selected from cobalt, zinc, copper or an oxide thereof.23. A method according to any one of the preceding clauses, wherein the first catalyst composition comprises an iron species, a manganese species, a cobalt species and a potassium species.24. A method according to clause 23, wherein the molar ratio of Fe: Mn: Co: K is about 100: 10:2: 10.25. A method according to any one of the preceding clauses, wherein the first catalyst composition further comprises a carbon species.26. A method according to any one of the preceding clauses, wherein second catalyst composition comprises a platinum species.27. A method according to any one of the preceding clauses, wherein second catalyst composition comprises a nickel species.28. A method according to any one of the preceding clauses, wherein the solid acid is selected from alumina, an alumina silicate or a zeolite.29. A method according to clause 28, wherein the zeolite is selected from a hydrogen zeolite, an acidic aluminosilicate zeolite or an acidic silicon aluminium phosphate (SAPO) zeolite.30. A method according to any one of the preceding clauses, wherein the solid acid is selected from the group consisting of HZSM-11, HZSM-22, HZSM-23, HZSM-35, HZSM-48, HMCM-22, SAPO-11, SAPO-5, A12O3and H-Beta zeolite.31. A method according to any one of the preceding clauses, wherein the solid acid is selected from SAPO-11 or AI2O3.32. A method according to any one of the preceding clauses, wherein the second catalyst composition comprises a platinum or nickel species supported on SAPO- 11 or AI2O3.33. A method according to any one of the preceding clauses, wherein the second catalyst composition is selected from Pt / SAPO-11, Pt / Al2O3or Ni / SAPO-11.34. A method according to any one of the preceding clauses, wherein the wt.% of metal to solid acid is about 0.5 wt.% to about 5 wt.%, suitably about 1 wt.%.35. A method according to any one of the preceding clauses, wherein contacting the intermediate product with the second catalyst composition is carried out at the same temperature or a lower temperature to contacting the feedstock with the first catalyst composition.36. A catalyst combination comprising a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species and a copper species (for example selected from one or more of a manganese species, a cobalt species, a zinc species and a copper species), and a second catalyst compositioncomprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.37. A catalyst combination according to clause 36, wherein the first catalyst composition and second catalyst composition are combined in the same composition.38. A catalyst combination according to clause 36 or 37, wherein the first catalyst composition comprises an iron species selected from an iron oxide, elemental iron, an iron carbide or a combination thereof.39. A catalyst combination according to any one of clauses 36 to 38, wherein the first catalyst composition comprises about 50 to about 90 wt. % of iron.40. A catalyst combination according to any one of clauses 36 to 39, wherein the first catalyst composition comprises a manganese species selected from a manganese oxide, elemental manganese, or a combination thereof.41. A catalyst combination according to any one of clauses 36 to 40, wherein the first catalyst composition comprises about 3 to about 10 wt. % of manganese.42. A catalyst combination according to any one of clauses 36 to 41, wherein the first catalyst composition about 3 to about 10 wt. % of an alkali metal species.43. A catalyst combination according to any one of clauses 36 to 42, wherein the alkali metal species is selected from a sodium or potassium species, suitably a potassium species.44. A catalyst combination according to any one of clauses 36 to 43, wherein the first catalyst composition comprises at least one further transition metal species.45. A catalyst combination according to clause 44, wherein the first catalyst composition comprises about 0.5 to about 5 wt. % of the further transition metal species.46. A catalyst combination according to clause 44 or 45, wherein the further transition metal species is selected from cobalt, zinc, copper or an oxide thereof.47. A catalyst combination according to any one of clauses 36 to 46, wherein the first catalyst composition comprises an iron species, a manganese species, a cobalt species and a potassium species.48. A catalyst combination according to clause 47, wherein the molar ratio of Fe: Mn: Co: K is about 100:10:2:10.49. A catalyst combination according to any one of clauses 36 to 48, wherein the first catalyst composition further comprises a carbon species.50. A catalyst combination according to any one of clauses 36 to 49, wherein second catalyst composition comprises a platinum species.51. A catalyst combination according to any one of clauses 36 to 50, wherein second catalyst composition comprises a nickel species.52. A catalyst combination according to any one of clauses 36 to 51, wherein the solid acid is selected from alumina, an alumina silicate or a zeolite.53. A catalyst combination according to clause 52, wherein the zeolite is selected from a hydrogen zeolite, an acidic aluminosilicate zeolite or an acidic silicon aluminium phosphate (SAPO) zeolite.54. A catalyst combination according to any one of clauses 36 to 53, wherein the solid acid is selected from the group consisting of HZSM-11, HZSM-22, HZSM-23, HZSM-35, HZSM-48, HMCM-22, SAPO-11, A12O3and H-Beta zeolite.55. A catalyst combination according to any one of clauses 36 to 54, wherein the solid acid is selected from the SAPO-11 or AI2O3.56. A catalyst combination according to any one of clauses 36 to 55, wherein the second catalyst composition comprises a platinum or nickel species supported on SAPO-11 or AI2O3.57. A catalyst combination according to any one of clauses 36 to 56, wherein the second catalyst composition is selected from Pt / SAPO-11, Pt / Al2O3or Ni / SAPO-11.58. A catalyst combination according to any one of clauses 36 to 57, wherein the wt.% of metal to solid acid is about 0.5 wt.% to about 5 wt.%, suitably about 1 wt.%.59. A system for the production of a product comprising one or more alkanes comprising one or more reactors, said one or more reactors comprising a catalyst combination according to any one of clauses 36 to 58.60. A system according to clause 59, wherein the one or more alkanes are one or more saturated acyclic alkanes.61. A system according to clause 59 or 60, wherein the alkanes are C5+ alkanes, suitably C8-16 alkanes.62. A system according to any one of clauses 59 to 61, wherein the product comprises at least about 90 wt.% of alkanes.63. A system according to any one of clauses 59 to 62, wherein the product has a ratio of a ratio of alkene:alkane of about 0.05 or less, suitably about 0.01 or less.64. A system for the production of a product comprising one or more alkanes comprising one or more reactors;a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species and a copper species (for example selected from one or more of a manganese species, a cobalt species, a zinc species and a copper species); and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species; wherein the first and second catalyst composition are contained in the one or more reactors.65. A system according to clause 64, wherein the one or more alkanes are one or more saturated acyclic alkanes.66. A system according to clause 64 or 65, wherein the alkanes are C5+ alkanes, suitably C8-16 alkanes.67. A system according to any one of clauses 64 to 66, wherein the product comprises at least about 90 wt.% of alkanes.68. A system according to any one of clauses 64 to 67, wherein the product has a ratio of a ratio of alkene:alkane of about 0.5 or less, suitably about 0.01 or less.69. A system according to any one of clauses 64 to 68, wherein the system comprises only one reactor. 70. A system according to clause 69, wherein the reactor contains the first catalyst composition and the second catalyst composition in separate fixed beds within said reactor.71. A system according to clause 70, wherein the reactor comprises one or more inlets for supplying one or more feedstock gases and the first catalyst composition is arranged within said reactor such that said composition is contacted first by the feedstock gases.72. A system according to clause 71, wherein the second catalyst composition is arranged downstream to the first catalyst composition within the reactor.73. A system according to clause 69, wherein the first catalyst composition and the second catalyst composition are in the same fixed bed within the reactor.74. A system according to any one of clauses 64 to 73, further comprising one or more fractionating means.75. A system according to any one of clauses 64 to 68, wherein the system comprises only two reactors. 76. A system according to clause 75, wherein a first reactor contains the first catalyst composition and a second reactor contains the second catalyst composition.77. A system according to clause 76, wherein the second reactor comprises an outlet which is coupled to at least one fractionating means.78. A system according to clause 76, wherein the first reactor comprises an outlet which is coupled to at least one fractionating means, and the second reactor has an inlet which is arranged to receive an input from the at least one fractionating means.79. A system according to any one of clauses 64 to 78, wherein the first catalyst composition comprises an iron species selected from an iron oxide, elemental iron, an iron carbide or a combination thereof.80. A system according to any one of clauses 64 to 79, wherein the first catalyst composition comprises about 50 to about 90 wt. % of iron.81. A system according to any one of clauses 64 to 80, wherein the first catalyst composition comprises a manganese species selected from a manganese oxide, elemental manganese, or a combination thereof.82. A system according to any one of clauses 64 to 81, wherein the first catalyst composition comprises about 3 to about 10 wt. % of manganese.83. A system according to any one of clauses 64 to 82, wherein the first catalyst composition about 3 to about 10 wt. % of an alkali metal species.84. A system according to any one of clauses 64 to 83, wherein the alkali metal species is selected from a sodium or potassium species, suitably a potassium species.85. A system according to any one of clauses 64 to 84, wherein the first catalyst composition comprises at least one further transition metal species.86. A system according to clauses 85, the first catalyst composition comprises about 0.5 to about 5 wt. % of the further transition metal species.87. A system according to clause 85 or 86, wherein the further transition metal species is selected from cobalt, zinc, copper or an oxide thereof.88. A system according to any one of clauses 64 to 87, wherein the first catalyst composition comprises an iron species, a manganese species, a cobalt species and a potassium species.89. A system according to clause 88, wherein the molar ratio of Fe: Mn: Co: K is about 100: 10:2: 10.90. A system according to any one of clauses 64 to 89, wherein the first catalyst composition further comprises a carbon species.91. A system according to any one of clauses 64 to 90, wherein second catalyst composition comprises a platinum species.92. A system according to any one of clauses 64 to 91, wherein second catalyst composition comprises a nickel species.93. A system according to any one of clauses 64 to 92, wherein the solid acid is selected from alumina, an alumina silicate or a zeolite.94. A system according to clause 93, wherein the zeolite is selected from a hydrogen zeolite, an acidic aluminosilicate zeolite or an acidic silicon aluminium phosphate (SAPO) zeolite.95. A system according to any one of clauses 64 to 94, wherein the solid acid is selected from the group consisting of HZSM-11, HZSM-22, HZSM-23, HZSM-35, HZSM-48, HMCM-22, SAPO-11, A12O3and H-Beta zeolite.96. A system according to any one of clauses 64 to 95, wherein the solid acid is selected from the SAPO-11 or AI2O3.97. A system according to any one of clauses 64 to 86, wherein the second catalyst composition comprises a platinum or nickel species supported on SAPO-11 or AI2O3.98. A system according to any one of clauses 64 to 97, wherein the second catalyst composition is selected from Pt / SAPO-11, Pt / Al2O3or Ni / SAPO-11.99. A system according to any one of clauses 64 to 98, wherein the wt.% of metal to solid acid is about 0.5 wt.% to about 5 wt.%, suitably about 1 wt.%.EXAMPLES1. Catalyst Preparation

[0233] A Fe-Co-Mn-K catalyst was used in the first catalyst bed prepared by the following Organic Combustion Method (OCM); citric acid was used as the organic compound. Typically, the Fe-Co-Mn-K catalyst with a molar ratio of 100:2:10:10 was prepared from citric acid (99%, Thermo Scientific), iron (III) nitrate nonahydrate (98%, Thermo Scientific), cobalt(II) nitrate hexahydrate (98%, Sigma-Aldrich), manganese (II) nitrate (50%, w / w aq. solution, Thermo Scientific) and potassium carbonate (99%, Sigma-Aldrich), in a molar ratio of citric acid: (Fe+Co+Mn+K)= 1, and a weight ratio of (Fe- and Co- and Mn- and K- precursors + citric acid) / water = 1:1. Mix iron nitrate salt, citric acid and water in a beaker. This initial mixture was stirred overnight to form a homogeneous aqueous solution and heated at 80°C for 1-2 h to obtain a citric acid-based slurry. The slurry was dried at 80-100°C overnight in the drying oven. Then, the resultant viscous paste was heated at 2°C / min to 350°C and maintained for 4 hours to produce a powder catalyst.

[0234] Catalysts applied in the second catalyst bed were prepared by a wet-impregnation method. Firstly, the various solid acids, e.g. zeolite molecular sieves (MS) were treated with NH4NO3. The weighted support, for example, Beta-Zeolite MCM-22, ZSM-22, ZSM-48, ZSM-11, ZSM-23, ZSM-35, Y zeolite, was put into a flask and NH4NO3 aqueous solution 1.0 mol / l was also added to the flask, and then the mixture was stirred and refluxed for 2 hours at temperature of 80-90°C. Then, the mixture was dried at 80-100°C overnight in the drying oven; the resultant viscous paste was heated at 2°C / min to 500°C and maintained for 4 hours to obtain the hydrogenous zeolite. Platinum, palladium or nickel was introduced by a wet-impregnation method, to obtain supported products with the amounts of metal indicated in the table below.

[0235] For platinum, the weighed platinum nitrate solution (Pt 15% w / w, Thermo Scientific), and citric acid (99%, Thermo Scientific) were dissolved in deionized water (5 mL). The molar ratio of platinum nitrate and citric acid was 1:1. Then 5 g solid acid support, such as zeolite or alumina, for example, SAPO-11, H-Beta-Zeolite, HMCM-22, HZSM-22, HZSM-48, HZSM-11, HZSM-23, HZSM-35, HY, A12O3, was added into the solution. After the mixture was kept at ambient temperature for 24 hours, the mixture was dried at 60°C for 12 h andcalcined at 500°C for 6 h in air to produce the hydrogenation catalysts Pt / MS or Pt / Al2O3with a molar ratio of from 0.1: 100 to 2:100.

[0236] For palladium and nickel, Pd / MS, Pd / Al2O3, Ni / MS, and Ni / Al2O3were prepared by the same method, but with using palladium nitrate hydrate (99.8%, Thermo Scientific) or nickel nitrate hexahydrate (Alfa Aesar) instead of platinum nitrate.

[0237] Table 1 provides a description of each of the catalysts used in the following hydrogenation experiments. The SOZ-P4 catalyst listed in Table 1 can be acquired from ZR Catalyst, and the RHI-DW 130S / Z catalysts listed in Table 1 can be acquired from Rezel Corporation. SOZ-P4 is a catalyst based on zeolite as a carrier and loaded with platinum and other metals.Table 1Catalyst Reference Catalyst DescriptionNumber Composition Wt. ratio of metal: support0 Fe-Co-Mn-K (100:2:10:10*) Unsupported01 Pt / SAPO-11 1 10002 Pt / Beta-zeolite 1 10003 Pt / HMCM-22 1 10004 Pt / HZSM-22 1 10005 Pt / HZSM-48 1 10006 Pt / HZSM-11 1 10007 Pt / HZSM-23 1 10008 Pt / HZSM-35 1 10009 Pt / Al2O31 20010 Pd / Al2O31 10011 Pd / SAPO-11 1 10012 Ni / SAPO-11 5 10013 Pt-Pd / SAPO-11 0.1:0.3:10014 A12O3- 15 SAPO-11 - 16 SOZ-P4 (Commercial shapedcatalyst, Pt / SAPO-11)17 PdPt / ZSM-4818 RHI-DW130S (Commercial shapedcatalyst, Pt / SAPO-11)19 RHI-DW130Z (Commercial shapedcatalyst, Pt / ZSM-48)20 HZSM-23 - *molar ratio of metal atoms2. Catalyst evaluation - CO2 Hydrogenation

[0238] A CO2 hydrogenation experiment was carried out in a stainless-steel fixed bed reactor with an inner diameter of 1.2 cm. Firstly, 1.0 g of one of catalysts 01-22 and 6.0 g SiC were mixed and loaded into reactor, and then 2.0 g catalyst 0 and 4.0 g SiC were mixed and loaded into the same reactor. Prior to the reaction, the catalysts were in situ activated with syngas (H2: CO = 2: 1) at atmospheric pressure, with a GHSV (gas hourly space velocity) of 600 mL g-1h-1, at 320°C for 16h. Following reactor cooling to below 50°C, a gas mixture of 3:1 H2: CO2and N2(as an internal standard gas) was introduced at a gas flow of 80 mL min-1(GHSV = 2400 mL g-1h-1).

[0239] The reactor was then heated at a rate of 2°C / min. to 300°C. The reaction pressure was controlled at 10 bar (IMPa) using a back pressure regulator. The effluent gaseous products were analysed using an online Gas Chromatograph (Agilent 8890 GC) with flame ionization (FID) and thermal conductivity detectors (TCD), andthe collected liquid products were analysed by Gas Chromatograph Mass Spectrometry (Agilent 5977B GC / MSD) with FID detector. The process flow diagram is shown in Figure 1.

[0240] The CO2 and H2conversion and product selectivity’s were calculated from the following relationships:n — ^2 inletvp.'-jU2,inlet M '-jU2,outletCO2conversion = - 2 outiet -x 100o / oCO2,inletu > ^2 inletvun2 inlet MA n2 outletH2conversion = - 2 outlet -X^QQO / Q”2 inlet^2 inlet v pnMA'-jUoutletCO yield =2 out‘e‘ - x 100%CO2, inletCO yieldCO selectivity = - x 100%CO2conversion„xJ%*LxCn||mCnHmyield = -2-^i - 2^ x 100% (n=l,2,3,4)co2, inlet4C5+yield = (CO2conversion — CO yield — CnHmyield) x 100%n=lCnHmyieldselectivity in hydrocarbons = - - - - x 100%CO2conversion x (1 — CO selectivity)selectivity of olefinratio of olefin to paraffin = — - - - — —selectivity of paraffin

[0241] The catalysts performance evaluation results are shown in Table 2.Table 2Convers- CO Selectivity and distribution in Ratio of olefin to paraffin in Compo- Catalysts ion / % hydrocarbons / % 2 as products sition**CO2H2CO CH4C2-C40C2-C4=Cs+C2 C3C4Fe-Co- Mn-KCatalyst 0 43.84 44.39 6.48 13.94 4.39 29.719 51.95 4.77 8.89 7.30 (100:2:10:10)Catalyst Pt / SAPO-11 43.80 44.46 8.17 12.81 36.00 0.18 51.01 0.00 0.00 0.01 0+01(1:100)Pt / Beta- Catalyst 43.79 44.83 9.11 14.35 44.37 0.05 41.229 0.00 0.00 0.00 0+02 Zeolite(1:100)Pt / HMCCatalyst M-22 43.42 44.69 7.65 13.67 41.64 0.00 44.69 0.00 0.00 0.00 0+03(1:100)Convers- CO Selectivity and distribution in Ratio of olefin to paraffin in Compo- Catalysts ion / % hydrocarbons / % 2 as products sition**CO2H2CO CH4 C2-C4° C2-C4=Cs+C2C3Cr Pt / HZSMCatalyst -22 35.12 37.44 12.62 17.30 60.99 0.00 21.71 0.00 0.00 0.00 0+04(1:100)Pt / HZSMCatalyst -48 40.93 42.39 9.76 16.31 44.29 0.00 39.40 0.00 0.00 0.00 0+05(1:100)Pt / HZSMCatalyst -11 38.27 40.47 10.54 15.79 64.02 0.00 20.19 0.00 0.00 0.00 0+06(1:100)Pt / HZSMCatalyst -23 40.45 42.25 9.64 14.66 51.87 0.09 33.39 0.00 0.00 0.00 0+07(1:100)Pt / HZSMCatalyst -35 41.58 43.19 9.20 15.72 49.37 0.04 34.88 0.00 0.00 0.00 0+08(1:100)Catalyst Pt / Al2O341.89 43.17 9.21 15.19 39.37 0.06 45.38 0.00 0.00 0.00 0+09 (0.5:100)Catalyst Pd / Al2O340.28 42.22 9.17 15.10 40.05 0.50 44.35 0.00 0.01 0.06 0+10 (1:100)Pd / SAPOCatalyst -11 43.90 44.34 8.58 12.67 37.88 0.74 48.70 0.00 0.00 0.07 0+11(1:100)Pt- Catalyst 42.23 42.59 8.97 11.41 34.91 0.94 52.73 0.00 0.01 0.08 0+13 Pd / SAPO-11Catalyst0+14 A12O341.17 41.03 7.79 13.78 5.12 34.90 46.20 5.15 8.53 6.91 Catalyst0+15 SAPO-11 39.67 39.09 8.34 15.90 7.70 50.36 26.04 5.89 7.69 6.11 Catalyst0+16 SOZ-P4 42.84 43.17 8.19 12.84 24.79 12.48 49.88 0.07 0.59 1.44 Catalyst PdPt / ZS0+17 M-48 41.15 43.21 7.51 12.27 46.62 1.45 39.66 0.00 0.00 0.09 Catalyst RHI- 0+18* 38.07 47.22 9.07 11.77 37.29 0.01 50.94 0.00 0.00 0.00 DW130SCatalyst RHI- 0+19* DW130Z 37.57 47.07 9.93 13.18 42.86 0.00 43.96 0.00 0.00 0.00 Catalyst 0 HZSM- 30.79 30.16 13.42 16.81 23.54 37.28 22.38 1.98 1.21 1.61+20 23* The feedstock of H2: CO2is a molar ratio of 2.5: 1.** for rows corresponding to combinations of two catalysts (Catalyst 0 and a second catalyst), only the composition of the additional (second) catalyst is listed in column 2, for brevity.

[0242] It can be seen from Table 2 that the alkane selectivity in the gas products is nearly 100% for the hydrogenation catalysts comprising platinum or palladium, and more specifically for the hydrogenation catalysts comprising platinum or palladium on a solid acid support.

[0243] The results of quantitative analysis by GC-MS / FID for the liquid product is shown in Table 3.Table 3 - Quantitative analysis of the GC-MS results for the liquid product ClttaassyCii**tomposonCatalyst Fe-Co-Mn-K0 15.66 79.22 5.12 13.29 0.23 0.00 68.74 7.42 0.00 3.05 7.27 (100:2:10:10)Catalyst Pt / SAPO-110+01 14.90 81.21 3.89 71.91 18.79 1.05 0.53 0.00 0.00 7.58 0.13(1:100)Catalyst Pt / Beta- 0+02 Zeolite 14.89 81.93 3.19 68.93 17.64 2.59 0.00 0.17 0.00 10.34 0.33(1:100)Catalyst Pt / HMCM- Sihttrag0+03 23.23 73.66 3.11 74.722 (1:100) A / lk%ane1 21.00 2.36 0.00 0.00 0.00 1.74 0.18 Catalyst Pt / HZSM-220+04 23.86 72.62 3.52 69.65 2 Bhdrance6.02 1.97 0.00 0.00 0.00 2.35 0.00(1:100) A / lk%anePt / HZSM-48 Catalyst0+05 24.51 74.83 0.66 74.34 21.52 1.93 0.00 0.00 0.00 2.21 0.00(1:100) C / llk%coaaneyCatalyst Pt / HZSM-1123.10 75.13 1.76 72.22 15.01 3.26 0.00 0.00 0.00 9.51 0.000+06 (1:100)Catalyst Pt / HZSM-2317.29 79.75 2.97 55.72 36.66 2.94 0 Si A / hlk%.ttragene 0+07 00 0.00 0.00 4.67 0.00(1:100)Catalyst Pt / HZSM-3510.22 86.23 3.55 63.79 29.12 2.70 0.00 Bhd 0rance.00 0.00 4.39 0.000+08 (1:100) A / lk%eneCatalyst Pt / Al2O322.25 72.67 5.08 71.71 17.89 2.16 0.69 0.31 0.00 6.18 1.060+09 (0.5:100) C / llk%coaeneyCatalyst Pd / Al2O320.84 76.77 2.39 71.10 19.41 1.77 0.75 0.00 0.21 3.60 3.150+10 (1:100)Aitromac Pd / SAPO-11 Catalyst 7.64 90.08 2.28 56.71 36.67 1.40 0.00 0.28 0.00 4.93 0.00 hdbrocarony 0+11 (1:100) / % Catalyst Pt-Pd / S APO- 24.32 70.90 4.78 75.62 18.31 1.18 2.10 0.63 0.00 0.98 1.180+13 11Catalyst O / %tgenaexy 18.83 70.65 10.51 18.54 0.00 0.00 70.54 2.34 0.00 3.44 5.14 A12O30+14Catalyst 36.51 63.49 0.00 25.47 0.81 2.63 13.08 40.07 1.16 13.29 3.49 SAPO-110+15Catalyst SOZ-P4 30.10 67.68 2.23 56.29 27.18 0.00 2.21 10.34 0.00 3.98 0.000+16PdPt / ZSM- Catalyst 23.24 76.76 0.00 30.79 49.07 13.87 0.00 0.00 0.00 6.27 0.000+17 48RHI- Catalyst 18.77 77.55 3.67 75.27 21.68 1.15 0.00 0.00 0.00 1.90 0.000+18* DW130SRHI- Catalyst 22.31 77.69 0.00 55.85 39.68 1.71 0.00 0.00 0.00 2.76 0.000+19* DW130ZCatalyst HZSM-23 22.34 77.66 0.00 13.22 6.26 2.69 0.27 5.89 25.10 46.56 0.000 +20* The feedstock of H2: CO2is a molar ratio of 2.5: 1.** for rows corresponding to combinations of two catalyst (Catalyst 0 and a second catalyst), only the composition of the additional (second) catalyst is listed in column 2, for brevity.

[0244] It can be seen from Table 3, that the catalysts with Pt or Pd showed higher alkane selectivity vs. alkene selectivity in the liquid products, the total ratio of alkenes to alkanes being less than 0.01 for most hydrogenation catalysts with Pt or Pd.

[0245] The combination of catalyst 0 with catalysts 04, 07, 08, and 11 in particular showed high hydroisomerisation ability, with significant increases in the branched alkane fraction.

[0246] Most of the products were saturated hydrocarbons, according to the results of quantitative analysis, and the ratio of total alkenes to alkanes is less than 0.01 for most hydrogenation catalysts with Pt or Pd.

[0247] The catalysts Pt / HZSM-22, Pt / HZSM-23, Pt / HZSM-35, Pt / HMCM-22, Pt / SAPO-11, Pd / SAPO-11, PdPt / ZSM-48, RHI-DW130S and RHI-DW130Z also showed high activity for hydrocarbon hydro-isomerisation ability.

[0248] Figures 2a-c show the performance of catalyst 0 as a function of time. Consistent conversion of hydrogen and CO2 is maintained for over 80 hours (Fig. 2a). C5+ product are prepared with the highest selectivity followed by C2-C4 alkenes (Fig. 2b). Molar ratios of olefin-to-paraffin at steady state are in the range of 4 to 9 (Fig. 2c).

[0249] Figures 3a-c show the performance of catalyst 0 and catalyst 01 in the same reactor as a function of time. Similar to the situation with catalyst 0 alone, consistent conversion of hydrogen and CO2 is maintained for over 80 hours (Fig. 3a) and once more C5+ products are prepared with the highest selectivity (Fig. 3b). However, in contrast to catalyst zero alone the olefin fraction in the C2-4 range has almost entirely converted to paraffins (Fig.3b and 3 c).

[0250] Figures 4 and 5 show the GC-MS total ion chromatogram (TIC) of the liquid products from each of the reactions with catalyst 0 only and catalyst 0 and 01 in the same reactor.

[0251] Comparing Figure 4 to Figure 5 it is evident that most of the alkenes have been converted to alkanes with the addition of catalyst 01 to catalyst 0. It is also evident that there are more branched hydrocarbons in Figure 5 (the smaller peaks besides the main peaks).3. Catalyst evaluation - CO2 Hydrogenation

[0252] A CO2 hydrogenation experiment was carried out in a tandem reactors rig, with two stainless-steel fixed bed reactors with an inner diameter of 1.2 cm. Firstly, 2.0 g catalyst 0 and 4.0 g SiC were mixed and loaded into reactor 1, and 1.0 g catalyst 09 and 6.0 g SiC were mixed and loaded into reactor 2. Prior to the reaction, the catalysts were in situ activated with syngas (H2: CO = 2:1) at atmospheric pressure, with a GHSV (gas hourly space velocity) of 600 mL g-1h-1, at 320 °C for 16 h. Following reactor cooling to below 50°C, a gas mixture of 3: 1 H2: CO2 and N2(as an internal standard gas) was introduced at a gas flow of 80 mL min-1(GHSV = 2400 mL g’1h’1).

[0253] Reactor 1 was then heated at a rate of 2°C / min to 300°C, and reactor 2 was heated at a rate of 2°C / min to a target temperature of either 200°C, 250°C, 280°C or 300°C. The reaction pressure was controlled at 10 bar (IMPa) using a back pressure regulator. The effluent gaseous products were analysed using an online Gas Chromatograph (Agilent 8890 GC) with flame ionization (FID) and thermal conductivity detectors (TCD), and the collected liquid products were analysed by Gas Chromatograph Mass Spectrometry (GC-MS) (Agilent 5977B GC / MSD) with FID detector. The Process Flow Diagram was shown in Figure 6.

[0254] The CO2 and H2conversion and product selectivity values were calculated as previously described. The catalysts performance evaluation results are shown in Tables 4 and 5.R 2teacor Table 4° / C ttemperareu Ratio of olefin to CO Selectivity and distribution inReactor 2 Conversion / % paraffin in gas hydrocarbons / %temperature product / °C C2- CO2 H2CO CHt C2-C40Cs+C2 c3C4C4=200 46.53 47.37 5.39 12.82 25.64 7.01 54.53 0.005 0.35 0.55 250 43.21 43.3 8.5 12.37 31.31 1.37 54.96 0 0.04 0.09 280 44.3 43.51 Si A / hlk%ttragane 12.11 13.21 33.14 0.54 53.11 0 0.01 0.04 300 46.06 43.47 19.6 14.82 35.51 0.08 49.59 0 0 0.01BhdranceA / lk%ane

[0255] As can be seen from Table 4, C5+ product selectivity stays essentially constant at a temperature of either 200°C or 250°C, but starts to drop slightly when the tem C / llk%coaaneyperature of the second reactor is increased to 280°C and continues to drop on increase of the reactor 2 temperature to 300°C. However, the ratio of olefimparaffin (i.e. alkene:alkane) in the C2, C3 and C4 products is seen to decrease with the increase in temperature.Si A / hlk%ttrageneTable 5 - Quantitative analysis of the GC-MS results Bhdrance for the liquid productA / lk%eneC / llk%coaeneyAitromachdbrocarony200 24.97 70.70 4.34 61.43 9.75 0.85 16.81 0.61 0.26 0.91 / % 9.39 250 20.88 76.22 2.90 67.25 10.38 1.06 6.51 0.49 0.00 5.98 8.33O / %tgenaexy 280 19.30 77.21 3.49 65.02 10.36 0.48 7.68 0.38 0.00 6.97 9.11 300 19.78 77.16 3.06 75.14 16.90 1.63 0.45 0.14 0.00 4.94 0.80

[0256] In addition to increasing proportion of paraffin to olefin with increasing temperature, Table 5 shows the proportion of branched alkane increasing relative to straight alkane as the temperature increases. Furthermore, the proportion of alkene decreased with the temperature increase, and the proportion of oxygenate decreased at a reaction temperature of 300°C.4. Catalyst evaluation - CO2 Hydrogenation

[0257] A CO2 hydrogenation experiment was carried out in a tandem reactors rig, with two stainless-steel fixed bed reactors with an inner diameter of 1.2 cm. Firstly, 2.0 g catalyst 0 and 4.0 g SiC were mixed and loaded into reactor 1, and 1.0 g catalyst 12 and 6.0 g SiC were mixed and loaded into reactor 2. Prior to the reaction, catalyst 12 was reduced with 10% H2 / N2at atmospheric pressure with a GHSV (gas hourly space velocity) of 6000 mL g-1h-1, at 700 °C for 2 h. Catalyst 0 was in situ activated with syngas (H2: CO = 2: 1) at atmospheric pressure, with a GHSV (gas hourly space velocity) of 600 mL g-1h-1, at 320 °C for 16 h. Following reactor cooling tobelow 50°C, a gas mixture of 3: 1 H2: CO2and N2(as an internal standard gas) was introduced at a gas flow of 80 mL R 2t meacorin-1(GHSV = 2400 mL g’1h’1).

[0258] ° / C ttemperareu Reactor 1 was then heated at a rate of 2°C / min to 300°C, and reactor 2 was heated at a rate of 2°C / min to 200°C. The reaction pressure was controlled at 10 bar (IMPa) using a back pressure regulator. The effluent gaseous products were analysed using an online Gas Chromatograph (Agilent 8890 GC) with flame ionization (FID) and thermal conductivity detectors (TCD), and the collected liquid products were analysed by Gas Chromatograph Mass Spectrometry (Agilent 5977B GC / MSD) with FID detector.

[0259] The CO2and H2conversion and product selectivity values were calculated as previously described. The catalyst performance evaluation results are shown in Tables 6 and 7.SihttragA / lk%aneTable 6BhdranceRatio of olefin to CO Se A / lk%anelectivity and distribution inReactor 2 Conversion / % paraffin in gas hydrocarbons / %temperature productC / llk%coaaney / °C C2- CO2H2CO CHt C2-C4° Cs+C2C3C4Sihttrag C4=200 45.04 45.73 6.55 12.41 30.33 A / lk% 1ene.69 55.57 0.002 0.04 0.13BhdranceA / lk%eneTable 7 - Quantitative analysis of the GC-MS results for the liquid productC / llk%coaeneyAitromachdbrocarony / %O / %tgenaexy 200 16.39 78.16 5.45 73.47 16.74 2.10 0.35 0.00 0.00 5.56 1.77

[0260] Tables 6 and 7 show that this catalyst combination provides high C5+ selectivity while keeping the olefimparaffin ratio low as well as providing a very low oxygenate concentration in the product.5. Catalyst evaluation - CO Hydrogenation (Fischer-Tropsch)

[0261] Fischer-Tropsch synthesis experiments were carried out in a stainless-steel fixed bed reactor with an inner diameter of 1.2 cm. Firstly, 1.0 g Pt / SAPO-11 (l:100)(catalyst 01) and 6.0 g SiC were mixed and loaded into reactor, and then 2.0 g catalyst Fe-Co-Mn-K (100:2: 10: 10) (catalyst 0) and 4.0 g SiC were mixed and loaded into the same reactor. Prior to the reaction, the catalysts were in situ activated with syngas (H2: CO = 2:1) at atmospheric pressure, with a GHSV (gas hourly space velocity) of 600 mL g-1h-1, at 320 °C for 16h. Following reactor cooling to below 50°C, a mixture of gas with an H2 / CO ratio of 2 and N2(as an internal standard gas) was introduced at a gas flow of 80 mL min-1(GHSV=2400 mL g-1h-1). The reactor was then heated at a rate of 2°C / min to 300°C. The reaction pressure was controlled at 10 bar (IMPa) using a back pressure regulator. The effluent gaseous products were analysed using an online Gas Chromatograph (Agilent 8890 GC) with flameionization (FID) and thermal conductivity detectors (TCD), and the collected liquid products were analysed by Gas C Clttaassyhromatograph Mass Spectrometry (Agilent 5977B GC / MSD) with FID detector. The catalysts performance evaluation results were shown in Table 8 and Table 9 as below.Table 8. The catalyst activity and products selectivity for catalyst (Fe-Co-Mn-K + Pt / SAPO-11) on Fischer-Tropsch.Ratio of olefin to CO2 Selectivity and distribution inSihttrag Conversion / % paraffin in gas A / lk%ane hydrocarbons / %Catalysts product Bhdrance C2- CO H2 CO2 A / lk%ane CH4C2-C40Cs+C2 C3C4C4=Catalyst 0+01 94.94 52.15 34.13 14.83 C / llk%coaaney 20.94 3.13 61.09 0.00 0.09 0.47SihttragTable 9. Quantitative analysis of the GC-MS results for the liquid productA / lk%eneBhdranceA / lk%eneC / llk%coaeneyCatalyst 19.59 67.41 13.00 76.06 10.96 0.22 3.83 1.63 0.00 Aitromac0+01 4.67 2.63hdbrocarony / %6. The performance of catalysts Fe-Co-Mn-K and RHI-DW130S with different loadings in CO2O / %tgenaexy Fischer-Tropsch reactions

[0262] The performance of different loading of Fe-Co-Mn-K and RHI-DW130S catalysts in CO2 Fischer-Tropsch reactions were evaluated, and the evaluation results are shown in Table 10 below.Table 10. The performance of catalyst Fe-Co-Mn-K and RHI-DW130S with different loading amounts in CO2 Fischer-Tropsch.Ratio of olefin to CO Selectivity and distribution in Conversion / % paraffin in gas hydrocarbons / % Catalyst bed Catalyst products 1 bed 2C2- C2- CO C5+C3H2CO2 CH4C2 C4 C40C4=RHI- Fe-Co-Mn- 38.42 47.89 9.36 13.20 40.00 0.02 46.78 0.00 0.00 0.00 DW130S K2.0g 2.0g*RHI- Fe-Co-Mn- 39.12 49.03 8.20 12.07 38.68 0.03 49.22 0.00 0.00 0.00 DW130S K2.0g 1.0g*RHI- Fe-Co-Mn- DW130S 42.63 44.68 8.11 14.42 39.57 0.24 45.78 0.00 0.00 0.01 K2.0g0.5gRHI- Fe-Co-Mn- DW130S 43.41 45.29 7.63 13.17 35.46 0.76 50.61 0.00 0.01 0.06 K2.0g0.25gRHI- Fe-Co-Mn- DW130S 44.25 45.96 7.23 12.35 33.47 1.27 52.90 0.00 0.02 0.10K2.0g0.2g

[0263] The catalysts were tested under reaction temperature of 300 °C, feedstock of H2and CO2, a GHSV of 2400 ml / (g h), and a pressure of 10 bar. The feedstock of H2and CO2generally has an H2: CO2molar ratio of 3:1, but forthose marked with an asterisk (*), the feedstock composition has an H2: CO2molar ratio of 2.5:1.

[0264] Table 10 shows that as the proportion of RHI-DW 130 catalyst decreased (in Catalyst bed 2), the alkane selectivity in the gas phase decreased, while the fraction of Cs+hydrocarbons increased.

[0265] The results of quantitative analysis for GC-MS / FID are shown in Table 11 below. In all cases, Catalyst Bed 1 comprised 2.0g of the Fe-Co-Mn-K catalyst.Table 11. Quantitative analysis of GC-MS / FID results for the liquid products of catalyst Fe-Co-Mn-K and RHI-DW130S with different loadings.Straigh Branch Straigh Branch AromaticCs- CycloCycloCatalyst bed C5-C7C17+ t -ed t -ed hydroOxygenCis alkane alkene 2 / % / % Alkane Alkane Alkene Alkene carbon ate / % / % / % / % / % / % / % / % / %RHI- DW130S 19.45 78.76 1.79 60.38 35.56 0.60 0.00 0.00 0.00 3.47 0.00 2.0g*RHI- DW130S 18.77 77.55 3.67 75.27 21.68 1.15 0.00 0.00 0.00 1.90 0.00 1.0g*RHI- DW130S 18.98 77.32 3.70 74.26 22.23 1.35 0.00 0.00 0.00 1.40 0.76 0.5gRHI- DW130S 18.79 77.01 4.20 75.88 20.46 1.20 0.00 0.00 0.00 1.57 0.90 0.25gRHI- DW130S 18.88 76.05 5.07 74.92 20.63 1.12 0.29 0.00 0.00 1.50 1.540.2g

[0266] The catalysts were tested under reaction temperature of 300 °C, feedstock of H2and CO2, a GHSV of 2400 ml / (g h), and a pressure of 10 bar. The feedstock of H2and CO2generally has an H2: CO2molar ratio of 3:1, but forthose marked with an asterisk (*), the feedstock composition has an H2: CO2molar ratio of 2.5:1.

[0267] Table 11 shows that, regardless of the loading amounts, the Fe-Co-Mn-K and RHI-DW130S catalysts exhibited similar alkane selectivity in the liquid products, with the majority of the products being saturated hydrocarbons.7. The performance of catalysts Fe-Co-Mn-K and RHI-DW130S mixed together in one catalyst bed in CO2Fischer-Tropsch reactions

[0268] In these experiments, the Fe-Co-Mn-K and RHI-DW130S catalysts were uniformly mixed together rather than being placed in two separate layers.

[0269] The CO2 Fischer-Tropsch evaluation results are shown in Table 12, below:Table 12. The performance of catalyst Fe-Co-Mn-K and RHI-DW130S mixed in one catalyst bed in CO2 Fischer-Tropsch reactions.Ratio of olefin to CO Selectivity and distribution inConversion / % paraffin in gas hydrocarbons / %Catalyst bed productsH2C 2 CO C2- C2- O CH4Cs+C2 C C4C40C4=3Fe-Co-Mn-K 2.0g +RHI-DW130S 1.0g 42.64 45.59 7.03 14.77 39.87 0.00 45.35 0.00 0.00 0.00 mixedFe-Co-Mn-K 2.0g +RHI-DW130S 0.67g 43.27 46.07 6.97 14.86 38.31 0.00 46.83 0.00 0.00 0.00 mixedFe-Co-Mn-K 2.0g +RHI-DW130S 0.25g 43.68 45.95 6.57 13.77 34.37 1.12 50.74 0.00 0.02 0.08 mixedFe-Co-Mn-K 2.0g +RHI-DW130S 0.22g 45.43 45.92 6.19 13.67 34.68 0.75 50.91 0.00 0.01 0.05mixed

[0270] The catalysts were again tested under reaction temperature of 300 °C, feedstock of H2and CO2, a GHSV of 2400 mL / (g h), and a pressure of 10 bar. The feedstock of H2and CO? had an H2: CO2molar ratio of 3:1.

[0271] Compared with the results in Table 10, Table 12 shows that when Fe-Co-Mn-K and RHI-DW130S were mixed and loaded together in a single catalyst bed, the CO2and H2conversions and the Cs+selectivity were similar to those obtained when the two catalysts were loaded in separate layers.

[0272] When Fe-Co-Mn-K and RHI-DW130S were mixed, increasing the amount of RHI-DW130S resulted in similar CO2and H2conversions, but the alkane selectivity in the gas products decreased, while the proportion of Cs+hydrocarbons increased slightly.

[0273] The results of quantitative analysis for GC-MS / FID are shown in Table 13 below.Table 13. Quantitative analysis of the GC-MS / FID results for the liquid products of catalyst Fe-Co-Mn-K and RHI-DW130S mixed in one catalyst bed.Straigh Branch Straigh Branch Aromati Cs- CycloCycloC5-C7C17+ t -ed t -ed c hydroOxygen Catalyst bed Cis alkane alkene / % / % Alkane Alkane Alkene Alkene carbon -ate / % / % / % / % / % / % / % / % / %Fe-Co-Mn-K2.0g + 20.07 77.33 2.60 74.49 22.74 1.60 0.00 0.00 0.00 1.16 0.00 RHI-DW130S1.0g mixedFe-Co-Mn-K2.0g + 20.66 76.40 2.93 76.07 20.27 1.17 0.00 0.00 0.00 2.10 0.39 RHI-DW130S0.67g mixedFe-Co-Mn-K2.0g + 19.08 76.43 4.49 76.42 19.79 1.30 0.00 0.00 0.00 0.88 1.61 RHI-DW130S0.25g mixedFe-Co-Mn-K2.0g + 18.15 77.39 4.46 73.71 20.73 1.33 0.00 0.00 0.00 1.76 2.47 RHI-DW130S0.22g mixed

[0274] The catalysts were all tested under a reaction temperature of 300 °C, feedstock of H2: CO2 (3:1 molar), a GHSV of 2400 mL / (g h), and a pressure of 10 bar, unless otherwise specified.

[0275] As shown in Table 13, when Fe-Co-Mn-K and RHI-DW130S were mixed and loaded together as a single catalyst bed, they produced liquid products. The alkene selectivities were similar to those obtained when the two catalysts were used in separate layers. In both cases, the products were predominantly saturated hydrocarbons (alkanes).8. The stability evaluation of catalysts Fe-Co-Mn-K and RHI-DW130S mixed in one catalyst bed in CO2 Fischer-Tropsch reactions.

[0276] The stability of the Fe-Co-Mn-K and RHI-DW130S catalysts, mixed in a single catalyst bed for CO2 Fischer-Tropsch synthesis, was evaluated under a feed of H2:CO2= 3: 1, a GHSV of 2400 mL / (g h), and a pressure of 10 bar. The results are shown in Figure 9. As can be seen in the figure, the catalyst remained stable over 800 hours.

[0277] When the temperature was increased from 300 °C to 310 °C and then to 320 °C, the conversions of H2and CO2increased, while the Cs+selectivity decreased. However, these temperature changes did not affect catalyst stability to any significant extent. When the temperature was lowered back to 310 °C from 320 °C, both the CO2 / H2 conversion and the Cs+selectivity returned to their original values.

[0278] Figure 9a shows the % conversion of CO2 and H2as a function of reaction time for the hydrogenation of CO2, with times at which reaction temperature was changed marked along the x-axis. Figure 9b shows the selectivity of various hydrocarbon products of this CO2 hydrogenation reaction, with reaction time and temperature changes again marked on the x-axis. Figure 9c shows molar ratio of olefin-to-paraffin (i.e. alkenes to alkanes) for the C2-C4 range with reaction time and temperature changes again marked on the x-axis.

[0279] The results of quantitative analysis for GC-MS / FID are shown in Table 14 below.Table 14. Quantitative analysis of the GC-MS / FID results for the liquid products of CO2 Fischer-Tropsch reactions using a mixed Fe-Co-Mn-K and RHI-DW130S catalyst in one catalyst bed, for catalyst stability evaluation.i Tme onStreamZL ■■CC / %57-63.5 18.15 77 CC / %816-.39 4.46 73.71 20.73 1.33 0 0 0 1.76 2.47 160.5 17.96 76.03 6.01 80.26 16.21 0.96 0 0 0 1.68 0.89 233.0 15.89 77.00 7 C / %17+.10 80.30 16.37 0.86 0 0 0 1.05 1.42 300 °C 328.0 16.16 75.94 7.90 82.70 13.40 0.99 0 0 0 1.42 1.49 467.0 12.32 78.45 9.23 8 Sihttrag6.47 13.04 0.40 0 0 0 0.10 - 567.0 14.32 77.92 7.76 80. A / lk%4ane2 16.98 0.45 0 0 0 1.32 0.84 310 °C 685.0 18.09 76.77 5.14 77.02 17.37 0.49 0 0 0 3.10 2.02 320 °CBhdrance802.0 14.26 79.26 6.48 75.85 19. A / lk%8ane6 0.38 0 0 0 2.30 1.60 310 °C

[0280] Again, the catalysts were tested under a feedsto Cllkcoaaneyc-k of H2: CO2 (3: 1 molar), a GHS V of 2400 ml / (g- h), and / %a pressure of 10 bar, unless otherwise specified.

[0281] It can be seen from Table 14 that the results of the quan Sihtttragitative analysis for the GC-MS / FID for the eight A / lk%enesampling liquid products with different times on stream are similar. It also can be seen that there are no alkenes in any of the eight samples. The selectivity for alkanes is therefore high, Bhd wranceith a small presence of aromatics.A / lk%ene9. Tandem reactor process Cllkcoaeney- / %

[0282] Figure 10 illustrates an example of a tandem reactor rig

[0500] for CO2 Fischer-Tropsch synthesis.

[0283] The rig

[0500] is arranged to be supplied with H2, one or more of CO and CO2, and Aitromac optionally also N2, as inlet gases. hdroy - / b% caron

[0284] The rig

[0500] comprises a first reactor

[0502] comprising a fixed catalyst bed comprising the first catalyst composition

[0503] arranged closest to the inlet such that it is contacted by the feedstock gases first, and Otgenaexy a second / % fixed bed comprising a second catalyst composition

[0504] arranged downstream to the first fixed bed relative to the inlet.i Rteacon

[0285] On leaving the first reactor

[0502] the outlet stream enters a first hot trap

[0505] which allows heavy ttemperareu hydrocarbons to be separated off. The remainder of the outlet stream then enters a first cold trap

[0506] , and then a separator

[0507] , allowing hydrocarbons with a chain-length suitable for use as fuel, and also water, to be separated off from the gaseous components (including e.g. short-chain hydrocarbons and remaining input gases).

[0286] The remaining lighter molecules then enter a second reactor

[0508] , The second reactor

[0508] is similar to the first

[0502] , again having comprising a fixed catalyst bed comprising the first catalyst composition

[0509] arranged closest to the inlet such that it is contacted by the input gases first, and a second fixed bed comprising a second catalyst composition

[0510] arranged downstream to the first fixed bed relative to the inlet.

[0287] On leaving the second reactor

[0508] the outlet stream enters a second hot trap

[0511] which allows heavy hydrocarbons to be separated off. The remainder of the outlet stream then enters a second cold trap

[0512] , and then a second separator

[0513] , allowing hydrocarbons with a chain-length suitable for use as fuel, and also water, to be separated off from any remaining gaseous components. The remaining gaseous components may be vented, or may be captured (e.g. for gas chromatography). This doubling of the reaction process flow therefore improvesoverall yield of fuel-suitable hydrocarbons by allowing further reactions of unreacted input gases and remaining short-chain hydrocarbons.

[0288] In an example implementation made according to this design 500 and used for experiments, both reactors [502, 508] are stainless-steel fixed bed reactors with an inner diameter of 1.2 cm. 2.0 g catalyst Fe-Co-Mn-K, 2.0 g hydrogenation catalyst with dilution of 4.0g SiC were loaded into the first reactor

[0502] , and 2.0 g catalyst Fe- Co-Mn-K, 2.0 g hydrogenation catalyst with dilution of 4.0g SiC were loaded into the second reactor

[0508] , respectively.

[0289] Catalyst 1 is the Fe-Co-Mn-K catalyst, and Catalyst 2 is the RHI-DW1305S catalyst, in both Reactor 1 and Reactor 2. Both reactors were loaded with the same catalyst arrangement: the Fe-Co-Mn-K catalyst on top and the RHI-DW1305S catalyst underneath. This configuration allows the CO2 / H2 feed to first produce olefin-rich hydrocarbons over the Fe-Co-Mn-K catalyst, after which the resulting hydrocarbons are hydrotreated by the downstream RHI-DW1305S catalyst.

[0290] Prior to the reaction, the catalysts were activated in situ with syngas (H2: CO ratio of 2: 1) at atmospheric pressure, with a GHSV (gas hourly space velocity) of 600 mL g-lh-1, at 320 °C for 16h. Following reactor cooling to below 50°C, a mixture of gas with an H2 / CO2 ratio of 3 (H2: CO of 3: 1) and N2(as an internal standard gas) was introduced at a gas flow of 80 mL min-1 (GSVH=2400 mL g-1 h-1). The reactors [502, 508] were then heated at a rate of 2°C / min to 300°C. The reaction pressure was controlled at 10 bar (IMPa) using a back pressure regulator located after the second reactor

[0508] , The effluent gaseous products were analysed using an online Gas Chromatograph (Agilent 8890 GC) with flame ionization (FID) and thermal conductivity detectors (TCD), and the collected liquid products were analysed by Gas Chromatograph Mass Spectrometry (Agilent 5977B GC / MSD) with FID detector.

[0291] The catalysts performance evaluation results are shown in Tables 15 and 16 below.Table 15. The catalyst activity and product selectivity for catalyst (Fe-Co-Mn-K + RHI-DW130S ) in CO2Fischer-Tropsch reactions.CO Selectivity and distribution inConversion / %hydrocarbons / %C2- H2CO2 CO CH4C2-C40C5+C4=64.84 60.45 4.30 12.75 37.01 - 50.24Table 16. Quantitative analysis of the GC-MS results for catalyst (Fe-Co-Mn-K + RHI-DW130S) Straigh Branch Straigh Branch AromaticCs- CycloCycloReactor C5-C7C17+ t -ed t -ed hydrocarb OxygenCis alkane alkene / % / % Alkane Alkane Alkene Alkene on ate / % / % / % / % / % / % / % / % / %Reactor 1 17.94 77.50 4.56 79.98 17.46 0.85 - - - 1.71 - Reactor 2 41.07 57.76 1.17 74.13 21.39 3.05 - - - 1.43 -10. Reactor process with recycling loop

[0292] Figure 11 illustrates an example of a reactor rig

[0600] for CO2 Fischer-Tropsch synthesis, with a single reactor

[0602] and a recycling loop.

[0293] The rig

[0600] comprises a reactor

[0602] comprising a fixed catalyst bed comprising the first catalyst composition

[0603] arranged closest to the inlet such that it is contacted by the feedstock gases first, and a second fixed bed comprising a second catalyst composition

[0604] arranged downstream to the first fixed bed relative to the inlet.

[0294] On leaving the reactor

[0602] the outlet stream enters a hot trap

[0605] which allows heavy hydrocarbons to be separated off. The remainder of the outlet stream then enters a cold trap

[0606] , and then a separator

[0607] , allowing hydrocarbons with a chain-length suitable for use as fuel, and also water, to be separated off from the gaseous components (including e.g. short-chain hydrocarbons and remaining input gases).

[0295] At least a portion of the remaining gaseous components are then “recycled” back to the inlet of the reactor

[0602] , passing through the catalyst beds [603, 604] for a second time. This may continue, with some gases passing through the reactor

[0602] more than twice. Any remainder of the remaining gaseous components can be removed from the process, either by venting, or collection and gas chromatography analysis, or otherwise.

[0296] CO2 Fischer-Tropsch synthesis experiments were carried out in a testing rig made to the design

[0600] of Figure 11, with a recycling loop. The reactor

[0600] was a stainless-steel fixed bed reactor with an inner diameter of 2 cm. 6.0 g shaped Fe-Co-Mn-K catalyst (on the top, to form the first catalyst bed

[0603] ) and 4.0 g Pt / SAPO-11 (on the bottom, to form the second catalyst bed

[0604] ) were and loaded into reactor

[0600] , Prior to the reaction, the catalysts were activated in situ with syngas (H2: CO = 2:1) at atmospheric pressure, with a GHSV of 600 mL g-1h-1, at 320 °C for 16 hours. Once the reactor

[0600] had cooled to below 50°C, a mixture of gas with an H2 / CO2 ratio of 2.7 (H2: CO = 2.7: 1) and N2(as an internal standard gas) was introduced at a gas flow of 240 mL min-1. The reactor

[0600] was then heated at a rate of 2°C / min to 300°C. The reaction pressure was controlled at 10 bar (IMPa) using a back pressure regulator.

[0297] The gas remaining in the rig

[0600] after the gas / liquid separator

[0607] was partially recycled back to the reactor

[0600] , and partially vented or sent for GC analysis. A recycling ratio of 2: 1 was selected. The recycling ratio is defined as ratio of the gas flow of the recycle gas to the feedstock gas flow. The effluent gaseous products were analysed using an online Gas Chromatograph (Agilent 8890 GC) with flame ionization (FID) and thermal conductivity detectors (TCD), and the collected liquid products were analysed by Gas Chromatograph Mass Spectrometry (Agilent 5977B GC / MSD) with FID detector.

[0298] The catalyst performance evaluation results are shown in Tables 17 and 18 below.Table 17. The catalyst activity and product selectivity for catalyst (Fe-Co-Mn-K + Ni / SAPO-11) in CO2 Fischer-Tropsch reactions.Conversion / % CO Selectivity and distribution in hydrocarbons / % H2CO2 CO CH4C2-C40C2C4=Cs+62.5 50.3 6.7 12.3 37.1 0.9 48.7Table 18. Quantitative analysis of the GC-MS results for hydrogenation catalyst (Fe-Co-Mn-K + Ni / SAPO-11) _ _ _ _ _ _ _Branche Branche AromaticC5- C17 Straight Straight7C8-C16 d Cycloalka d Cycloalke hydrocarb Oxygenate C 4- / % Alkane / Alkene / Alkane / ne / % Alkene / ne / % on / % / % / % % %% % / %0.638.7 60.6 61.7 22.5 1.98 2.21 - - 10.6 0.999

[0299] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference in their entirety and to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein (to the maximum extent permitted by law).

[0300] All headings and sub-headings are used herein for convenience only and should not be construed as limiting the invention in any way.

[0301] 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 unless otherwise paragraphed. No language in the specification should be construed as indicating any non-paragraphed element as essential to the practice of the invention.

[0302] The citation and incorporation of patent documents herein is done for convenience only and does not reflect any view of the validity, patentability, and / or enforceability of such patent documents.

[0303] This invention includes all modifications and equivalents of the subject matter recited in the paragraphs appended hereto as permitted by applicable law.

Claims

CLAIMS1. A method for producing a product comprising one or more alkanes, said method comprising:contacting a feedstock comprising (i) hydrogen and (ii) carbon dioxide and / or carbon monoxide with a first catalyst composition, wherein the first catalyst composition comprises an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species, to provide an intermediate product comprising olefins; optionally subjecting the intermediate product to one or more fractionating steps to provide a fractionated intermediate product; andcontacting said optionally fractionated intermediate product with a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species, so as to form a product comprising one or more alkanes.

2. A catalyst combination comprising a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species; and a second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species.

3. A system for the production of a product comprising one or more alkanes comprising:one or more reactors,a first catalyst composition comprising an iron species, an alkali metal species, and a further transition metal species selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species; anda second catalyst composition comprising a metal species and a solid acid, wherein the metal species is selected from one or more of a platinum, a palladium, a nickel and a cobalt species;wherein the first and second catalyst composition are contained in one or more of the reactors.

4. The invention according to any one of the preceding claims, wherein the further transition metal species is selected from one or more of a manganese species, a cobalt species, a zinc species, a zirconium species, and a copper species; optionally wherein the further transition metal species comprises a manganese species.

5. The invention according to any one of the preceding claims, wherein the alkali metal species:(a) is a potassium species, a sodium species, or a caesium species; and / or(b) is a potassium species.

6. The invention according to any one of the preceding claims, wherein the first catalyst composition comprises about 50 wt. % or more of iron.

7. The invention according to any one of the preceding claims, wherein the first catalyst composition comprises:a) about 50 to about 90 wt. % of iron; and / orb) about 3 to about 10 wt. % of the further transition metal species, optionally wherein the further transition metal species is a manganese species; and / orc) about 3 to about 10 wt. % of an alkali metal species, optionally wherein the alkali metal species is potassium.

8. The invention according to any one of the preceding claims, wherein the first catalyst composition further comprises (a) at least one further transition metal species, and / or (b) a carbon species.

9. The invention according to claim 8, option (a), wherein the further transition metal species is (i) selected from cobalt, zinc, and copper, or an oxide thereof; and / or (b) present in an amount from about 0.5 to about 5 wt. %.

10. The invention according to any one of the preceding claims, wherein the first catalyst composition comprises an iron species, a manganese species, a cobalt species and a potassium species, optionally wherein the molar ratio of Fe: Mn: Co: K is 100:(10 to 50):(0.5 to 5): (2 to 10), such as about 100:10:2:10.

11. The invention according to any one of the preceding claims, wherein the first catalyst composition is unsupported.

12. The invention according to any one of the preceding claims, wherein the second catalyst composition comprises a metal species and a solid acid catalyst, wherein the metal species is selected from one or more of a platinum species, a palladium species, and a nickel species.

13. The invention according to any one of the preceding claims, wherein the second catalyst composition comprises no more than lwt% of any metal species that is not a platinum species, a palladium species, or a nickel species.

14. The invention according to any one of the preceding claims, wherein the second catalyst composition comprises:a) only one metal species, wherein the metal species is selected from a platinum species, a palladium species, and a nickel species; orb) more than one metal species, wherein each metal species that is present is selected from the group consisting of: platinum species, palladium species, and nickel species.

15. The invention according to any one of the preceding claims, wherein the second catalyst composition comprises a platinum species and / or a nickel species as the metal species.

16. The invention according to any one of the preceding claims, wherein the second catalyst composition comprises the metal species at a level of about 0.1 wt.% to about 10 wt.%, with respect to the amount of solid acid.

17. The invention according to any one of the preceding claims, wherein the second catalyst composition has an amount of metal species of from about 0.5 wt.% to about 5 wt.%, optionally about 1 wt.%, with respect to the amount of solid acid.

18. The invention according to any one of the preceding claims, wherein the solid acid is selected from a metal oxide, such as a transition metal oxide, or an alumina silicate, such as a zeolite.

19. The invention according to any one of the preceding claims, wherein the solid acid is selected from an alumina or a zeolite, such as a protonated zeolite.

20. The invention according to any one of the preceding claims, wherein the solid acid is selected from the group consisting of (a) HZSM-5, HZSM-11, HZSM-22, HZSM-23, HZSM-35, HZSM-48, HMCM-22, SAPO-11, SAPO-5, AI2O3 and H-Beta zeolite; or (b) HZSM-11, HZSM-22, HZSM-23, HZSM-35, HZSM-48, HMCM-22, SAPO-11, AI2O3 and H-Beta zeolite.

21. The invention according to any one of the preceding claims, wherein the second catalyst composition is selected from Pt / SAPO-11, Pt / Al2O3or Ni / SAPO-11.

22. The invention according to any one of the preceding claims wherein the first catalyst comprises an iron species, a manganese species, a cobalt species, and an alkali metal species and the second catalyst composition is selected from Pt / SAPO-11, Pt / Al2O3or Ni / SAPO-11.

23. The method according to claim 1 or any one of the claims dependent thereon, wherein the feedstock is contacted with the first catalyst composition at a temperature of from about 200°C to about 500°C, suitably at about 300°C.

24. The method according to claim 1 or any one of the claims dependent thereon, wherein the intermediate product is contacted with the second catalyst at a temperature of from about 200°C to about 500°C, suitably at about 200°C to about 350°C, such as about 200°C to about 300°C.

25. The method according to claim 1 or any one of the claims dependent thereon, wherein:a) the feedstock is contacted with the first catalyst composition and the intermediate product is contacted with the second catalyst composition in the same reactor; orb) the feedstock is contacted with the first catalyst composition in a first reactor and the intermediate product is contacted with the second catalyst composition in a second reactor.

26. The method according to claim 25, wherein the or each reactor is independently selected from: a fixed bed reactor, a slurry bed reactor, a fluidised bed reactor and a moving bed reactor.

27. The method according to claim 25 or claim 26, wherein:a) the feedstock is contacted with the first catalyst composition and the intermediate product is contacted with the second catalyst composition in the same fixed bed reactor; orb) the feedstock is contacted with the first catalyst composition in a first fixed bed reactor and the intermediate product is contacted with the second catalyst composition in a second fixed bed reactor.

28. The method according to claim 1 or any one of the claims dependent thereon, wherein the feedstock is contacted with the first catalyst in a fixed bed reactor, and / or the intermediate product is contacted with the second catalyst in a fixed bed reactor.

29. The method according to claim 1 or any one of the claims dependent thereon, wherein the feedstock comprises (i) hydrogen and (ii) carbon dioxide, and optionally further comprises carbon monoxide.

30. The method according to claim 29, wherein the feedstock has a molar ratio of hydrogen to carbon dioxide of from 1.5 to 4; optionally from about 2 to about 3.

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