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Title:
SERIAL PROCESS FOR CONVERTING SYNGAS TO LIQUID HYDROCARBONS, DEVICE USED THEREFOR INCLUDING FT- AND HT-CATALYSTS, FT-CATALYST
Document Type and Number:
WIPO Patent Application WO/2018/162363
Kind Code:
A1
Abstract:
The invention relates, in a first aspect, to a process to convert a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) into liquid hydrocarbons by means of the combination of a Fischer-Tropsch solid catalyst and a hydrotreating solid catalyst in separate catalyst beds operated at different reaction temperatures, and, in a second aspect, to a multimodal porosity Fischer-Tropsch catalyst to be applied in said process and the method for preparing said Fischer-Tropsch catalyst.

Inventors:
SCHÜTH FERDI (DE)
PRIETO-GONZALEZ GONZALO (DE)
DUYCKAERTS NICOLAS (DE)
Application Number:
PCT/EP2018/055237
Publication Date:
September 13, 2018
Filing Date:
March 04, 2018
Export Citation:
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Assignee:
STUDIENGESELLSCHAFT KOHLE MBH (DE)
International Classes:
B01J23/745; B01J23/46; B01J23/75; B01J23/89; B01J29/04; B01J29/44; B01J35/00; B01J35/02; B01J35/10; B01J37/00; B01J37/02; B01J37/08; C07C1/04; C07C5/22; C07C5/27; C10G2/00; B01J37/18
Domestic Patent References:
WO2017009427A12017-01-19
WO2009014292A22009-01-29
WO2014007598A12014-01-09
Foreign References:
US6410814B22002-06-25
US20060144755A12006-07-06
US6410814B22002-06-25
US20110160315A12011-06-30
US7973086B12011-07-05
US20100160464A12010-06-24
Other References:
MERINO DAVID ET AL: "On the Way to a More Open Porous Network of a Co-Re/Al2O3Catalyst for Fischer-Tropsch Synthesis: Pore Size and Particle Size Effects on Its Performance", TOPICS IN CATALYSIS, BALTZER SCIENCE PUBLISHERS, BUSSUM, NL, vol. 59, no. 2, 6 August 2015 (2015-08-06), pages 207 - 218, XP035933564, ISSN: 1022-5528, [retrieved on 20150806], DOI: 10.1007/S11244-015-0436-3
JUNGANG WANG ET AL: "Textural Structure of Co-based Catalysts and their Performance for Fischer-Tropsch Synthesis", CATALYSIS LETTERS, KLUWER ACADEMIC PUBLISHERS-PLENUM PUBLISHERS, NE, vol. 140, no. 3 - 4, 24 September 2010 (2010-09-24), pages 127 - 133, XP019862336, ISSN: 1572-879X, DOI: 10.1007/S10562-010-0449-2
MA WENPING ET AL: "Fischer-Tropsch synthesis: Pore size and Zr promotional effects on the activity and selectivity of 25%Co/Al2O3catal", APPLIED CATALYSIS A: GENERAL, vol. 475, 19 January 2014 (2014-01-19), pages 314 - 324, XP028845483, ISSN: 0926-860X, DOI: 10.1016/J.APCATA.2014.01.016
YI ZHANG ET AL: "Preparation of alumina-silica bimodal pore catalysts for Fischer-Tropsch synthesis", CATALYSIS LETTERS, KLUWER ACADEMIC PUBLISHERS-PLENUM PUBLISHERS, NE, vol. 99, no. 3-4, 1 February 2005 (2005-02-01), pages 193 - 198, XP019275519, ISSN: 1572-879X
FREITEZ ET AL.: "Single-Stage Fischer-Tropsch Synthesis and Hydroprocessing: The Hydroprocessing Performance of Ni/ZSM-5/y-AI 0 under Fischer-Tropsch Conditions", IND. ENG. CHEM. RES., vol. 50, 2011, pages 13732 - 13741
BAO ET AL.: "A Core/Shell Catalyst Produces a Spatially Confined Effect and Shape Selectivity in a Consecutive Reaction", ANGEWANDTE CHEMIE INT. ED., vol. 47, 2007, pages 353 - 356
SARTIPI ET AL.: "Hierarchical H-ZSM-5-supported cobalt for the direct synthesis of gasoline-range hydrocarbons from syngas: Advantages, limitations, and mechanistic insight", JOURNAL OF CATALYSIS, vol. 305, 2013, pages 179 - 190, XP028674875, DOI: doi:10.1016/j.jcat.2013.05.012
"Handbook of Heterogeneous Catalysis", vol. 1, 2008, WILEY-VCH VERLAG GMBH & CO.
"Synthesis of solid catalysts", 2009, WILEY-VCH VERLAG GMBH & CO.
"Atlas of Zeolite Framework Types", 2001, ELSEVIER
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Claims:
CLAIMS

1 . Fischer-Tropsch-Catalyst (FT-catalyst) with a multimodal porosity,

having an active metal selected from Co, Fe, Ru or mixtures thereof on a a high surface area support selected from S1O2, T1O2, AI2O3, hydrated precursors thereof or any combination thereof,

having a surface area in the range of between 10 and 1 100 m2/g, preferably between 50 and 400 m2/g;

having a particle size in the range of 200 μιτι to 800 μιτι, preferably 300 μιτι to 700 μιτι, more preferably 400 μιτι to 600 μιτι and

having pores in a pore size distribution, with a first maximum in the mesopore range of 2 to 50 nm and with a second maximum in the macropore range of above 50 nm, whereby the percentage of mesopores is in the range of 20 to 95 % of the total pore volume, and the percentage of macropores is in the range of 5 to 80 % of the total pore volume.

2. FT-Catalyst with a multimodal porosity according to claim 1 , wherein the macropores are present in a distribution with a first maximum in the range of 50 to 200 nm and a second maximum in the range of 200 nm to 10 μιτι, whereby the percentage of macropores of 50 to 200 nm is in the range of 40 to 95 % of the total macropore volume, and the percentage of macropores of 200 nm to 10 μιτι is in the range of 5 to 60 % of the total macropore volume.

3. FT-Catalyst with a multimodal porosity according to claim 1 or 2, obtainable by a process comprising the steps of:

a. Preparing a suspension containing water, a dispersible alumina source and optionally an acid substance, wherein the alumina source is preferably selected from the group of hydragillite, bayerite, pseudoboehmite, amorphous gels, transition aluminas which comprise at least one phase taken from the group comprising rho, chi, eta, gamma, kappa, theta and alpha phases; Adding an organic polymer to the suspension obtained in step a), which polymer is preferably a non-ionic surfactant selected from the group which comprises:

i) alkyl-polyethylene oxides, with general formula R-O(EO)xH where R is a hydrophobic alkyl group with n carbon atoms, where n typically spans in the range from 1 to at least 20, EO represents an ethylene oxide building unit (OCH2CH2) with x ranging from about 7 to 40;

ii) alkyl-phenyl polyethylene oxides;

iii) polyethylene oxide (PEO)-polypropylene oxide-(PPO) block- copolymers;

iv) polysorbate-type surfactants formed by the ethoxylation of sorbitan followed by the addition of lauric acid,

and combinations thereof,

preferably, as organic polymer, a non-ionic surfactant of the alkyl- polyethylene oxide type of group i);

Subjecting the suspension obtained in step b) to a hydrothermal treatment under autogenous pressure in an autoclave, preferably in a temperature range from 300 K to 400 K, more preferably from 330 to 350 K, preferably over a time span from 12 h to 72, more preferably from 40 to 60 h;

Depressurizing the autoclave and drying the product obtained in step c) until the water content is below 10 wt%;

Thermally treating the dried product of step d) at an elevated temperature up to 1000 K under an oxidizing conditions, preferably under air, whereby the hydrocarbon polymer is combusted in the dried product of step d) and the product of step d) is calcined;

Impregnating the product of step e) with a solution of at least one salt of an active metal selected from Co, Ru and Fe, preferably according to the incipient wetness method, drying the impregnated product and submitting it to a preferably thermal treatment to convert said metal salt into a metal oxide or the corresponding metallic form. Device for converting a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) into liquid hydrocarbons, comprising:

a. a FT-catalyst according to any of claims 1 to 3,

b. a Hydrotreating catalyst (HT-catalyst), preferably in the form of a metal or a metal sulphide dispersed in the form of nanoparticles on particles of an acidic solid, which is preferably selected from an amorphous S1O2- AI2O3, a zeolite (crystalline aluminosilicate) or an acidic zeotype, c. an inlet for the feed stream, and

d. an outlet for the hydrocarbons,

wherein the FT-catalyst and the HT-catalyst are contained in separate compartments (units) of the device which compartments are in fluid communication with each other and where the HT-compartment is positioned downstream of the FT-compartment, preferably in a spatial distance sufficient to establish a temperature difference between the two catalysts of at least 20 K.

Process for converting a syngas feed stream comprising carbon monoxide and hydrogen as major components into liquid hydrocarbons, making use of the device according to claim 4, wherein

- a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) with a molar H2/CO ratio in the range of 0.5-3, preferably in the range of 1 -2, is provided to the inlet of a device according to claim 4 and further directed to the FT-catalyst operated at a reaction temperature range selected in the range of 423-513 K, preferably in the range of 460 to 500 K,

- the obtained gas mixture, without any fractionation, isolation or purification, is directed to the HT-catalyst operated at a reaction temperature range selected in the range of 483-623 K, preferably in the range of 503-553 K, and

- the obtained gaseous hydrocarbon mixture is directed to a collection vessel, whereby the operating temperature of the FT-catalyst is lower than the operating temperature of the HT-catalyst, and whereby the syngas space velocity is selected to achieve a CO conversion in the range of 5-100%, preferably in the range from 20-80%.

Use of a FT-catalyst according to any of claims 1 to 3 for converting a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) into liquid hydrocarbons.

Description:
SERIAL PROCESS FOR CONVERTING SYNGAS TO LIQUID HYDROCARBONS, DEVICE USED THEREFOR INCLUDING FT- AND HT-CATALYSTS, FT-CATALYST

FIELD OF THE INVENTION

The invention relates, in a first aspect, to a process to convert a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) into liquid hydrocarbons by means of the combination of a Fischer-Tropsch solid catalyst and a hydrotreating solid catalyst, in which the liquid hydrocarbon products display a particularly desired distribution with maximum contribution from primarily linear paraffins in the fraction corresponding to middle distillates and minimum contribution from the fraction corresponding to light tail-gas hydrocarbons (C 4- ). In a second aspect, the invention relates to a method for preparing a Fischer-Tropsch catalyst to be applied in said process.

BACKGROUND

The conversion of so-called synthesis gas (often abbreviated as "syngas") mixtures into hydrocarbons by means of catalytic processes represents an important approach for the manufacture of synthetic fuels, but also chemicals and specialties, from carbon resources alternative to petroleum. Syngas is a mixture typically composed of carbon monoxide (CO), hydrogen (H 2 ) and, in certain cases, also carbon dioxide (CO 2 ) as major components. This important and versatile commodity can be obtained from a large variety of carbonaceous feedstocks, e.g. via steam reforming or partial oxidation of natural gas, via gasification of coal, via gasification and/or reforming of biomass feedstocks, via hydrogenation of carbon dioxide, among other. Currently, large-scale syngas conversion processes exist in which the syngas is first generated, primarily via steam reforming of natural gas on a first solid catalyst. The generated syngas is purified and then converted on a second solid catalyst into a mixture of mostly n-paraffin hydrocarbons via the so- called Fischer-Tropsch synthesis. This reaction takes place on catalysts containing cobalt (Co), iron (Fe) or ruthenium (Ru) as catalytically active species, or precursors therefor, either in an unsupported (bulk) fashion or dispersed in the form of nanoparticles on a porous carrier, and possibly incorporating further components which play the role of structural and catalytic promoters to improve catalyst activity, selectivity or stability under standard operation conditions. The reaction proceeds via a surface chain-growth polymerization mechanism and therefore results in primarily linear hydrocarbon products which typically obey a so-called Anderson-Schulz-Flory (ASF) chain-length distribution. According to this distribution, the hydrocarbon products span a very wide range of chain-lengths, typically from Ci to C 5 o+, where the subscripts indicate the number of carbon atoms in the hydrocarbon molecule, and the selectivity to specific hydrocarbon fractions is intrinsically limited, meaning that the process leads to both desired and undesired hydrocarbon product fractions.

It is consensually believed that 1 -olefins (a-olefins) are a major primary product of the Fischer-Tropsch reaction. However, these primary products are rather reactive under the reaction conditions which are industrially relevant for this reaction, and typically undergo secondary reactions already before they egress from the Fischer-Tropsch catalyst particle were they formed. Such secondary processing involves re-adsorption of the a-olefins primary products on the metal sites of the Fischer-Tropsch catalyst followed by their incorporation into growing hydrocarbon chains and/or their hydrogenation into the corresponding n-paraffins. Since n- paraffins are significantly less reactive under the standard operation conditions, they typically do not undergo any further tertiary processing. These effects lead to an ultimate Fischer-Tropsch hydrocarbon product which consists essentially of linear, fully saturated n-paraffins, with only minor contributions from olefins and oxygenate compounds. Particularly if highly-active catalysts such as those based on cobalt or ruthenium as the major active species are applied in the process, the weight ratio of alpha-olefins to n-paraffins does not exceed - and is often significantly below - 0.5 for carbon chain lengths in the range of C3-C6, and below 0.2 for longer carbon chains. In the state of art, different Fischer-Tropsch hydrocarbon fractions are obtained through this process, chiefly tail-gas hydrocarbons (C 4- ), liquid hydrocarbons in the naphtha range (typically C5-C9), liquid hydrocarbons in the middle-distillates range (typically C10-C25) and solid waxes (typically C25+)- For the production of liquid fuels and specialties, the reaction conditions and the catalyst composition and structure are selected to favour a high chain-growth probability which therefore maximizes the production of long-chain paraffins (solid waxes) in the Fischer-Tropsch reactive step. These solid hydrocarbon products are then isolated and transported into separate units where they are upgraded to liquid lubricants and fuels by means of a third catalytic process involving the processing of said Fischer-Tropsch hydrocarbon products on a solid hydrotreating catalyst. The terms hydrocracking and hydroprocessing are also customarily used in the art to refer to the catalyst herein denoted as hydrotreating catalyst. The hydrotreating catalyst consists typically of a metal or a metal sulphide dispersed in the form of nanoparticles on an acidic solid. The acidic support is typically an amorphous S1O2-AI2O3, a zeolite (crystalline aluminosilicate) or other type of acidic zeotype. On this catalyst, the essentially linear Fischer-Tropsch hydrocarbons are subjected to reactions of skeletal isomerization and cracking resulting in hydrocarbon products of lower molecular weight. The middle distillates fraction is generally the most desirable product fraction, as it can be used as precursor for high cetane-number and sulfur- free synthetic diesel and jet fuels, or directly be blended into oil-derived diesel of jet fuel fractions. According to the invention, the hydrotreating upgrading step takes place under a high pressure atmosphere containing hydrogen and typically in the absence of carbon monoxide which might act as a poison on the metallic function of the hydrotreating catalyst and favour the production of undesired lighter hydrocarbons. Hence the separation of the unconverted syngas in between the Fischer-Tropsch and hydrotreating reaction steps is important for the ultimate product distribution.

While the above described multi-step process is technically and economically attractive for the exploitation of large natural gas wells, there is at present increasing interest in the exploitation of smaller, delocalized carbon resources into hydrocarbon fuels. Such resources include oil-associated, shale- and tight- natural gas wells, including those which are stranded and can only be exploited with offshore platforms, lignocellulosic biomass resources, including urban and forestry wastes, etc. For these small-scale feedstocks, compact syngas-to-liquid processes are desired, in which the overall process is significantly intensified and miniaturized and transportable liquid hydrocarbon products are produced from syngas in a single step, avoiding the need to recover and handle wax Fischer- Trospch products at an intermediate step between the Fischer-Tropsch and the product upgrading unitary operations.

For small-scale processes, the integration of the Fischer-Tropsch and hydrotreating catalytic steps in a single reactor, i.e. without any intermediate product fractionation, separation or purification process step, in a fashion which is typically referred to as hybrid, bifunctional or tandem catalysis in the art, was considered by the inventors to be advantageous. In this way, the syngas feed is converted into hydrocarbons on a Fischer-Tropsch solid catalyst, and the Fischer- Tropsch hydrocarbon products can react directly on the hydrocracking catalyst were the solid waxes are cracked down to lighter hydrocarbons so that the overall hydrocarbon product comprises exclusively, or at least primarily, gas and liquid hydrocarbons. While transportable liquid hydrocarbons are the product of interest, the production of tail-gas hydrocarbons is significantly penalizing for the efficiency and economy of the process and should be ideally minimized.

In the prior art, processes are disclosed in which a Fischer-Tropsch catalyst and a hydrotreating catalyst are integrated to achieve the wax-free, single-step production of liquid hydrocarbons by catalytic conversion of syngas mixtures. Most of these processes can achieve, under certain operation conditions, a full, or close to full, depletion of the solid wax hydrocarbons from the products, being the fraction of C23+ hydrocarbons in said products <5 wt%. However, important limitations are still faced in this integration of Fischer-Tropsch and hydrotreating catalysts, namely the relatively high selectivity to tail-gas hydrocarbons and limited selectivity to middle-distillates hydrocarbons.

US6410814 by Fujimoto and Tsubaki discloses a process in which a cobalt-based Fischer-Tropsch catalyst and a hydrotreating catalyst are integrated in separate an consecutive packed beds along a tubular reactor to convert syngas into liquid hydrocarbons in a single step. Under standard reaction conditions, the Fischer- Tropsch catalyst alone produces a hydrocarbon product stream which comprises essentially only n-paraffins, as customary for cobalt-based Fischer-Tropsch catalysts under standard operation conditions. When the Fischer-Tropsch and the hydrotreating catalyst are integrated to produce liquid hydrocarbons in a single step, the hydrocarbon products are free from waxes (C23+) but do not contain hydrocarbons in the range of middle-distillates either. In addition, the contribution from tail-gas hydrocarbons to the overall hydrocarbon products exceeds 35%.

US201 1/0160315 by Kibby et al. discloses a process in which a cobalt-based Fischer-Tropsch catalyst and a hydrotreating catalyst are integrated in separate and consecutive packed beds along a tubular reactor to convert syngas into liquid hydrocarbons in a single step. Under preferred embodiments, the process leads to a product hydrocarbon mixture in which the fraction of tail-gas hydrocarbons (C 4- ) contributes >20 wt% and the fraction of middle-distillates (given as C10-C22 in said document) accounts for <35 wt%, at CO conversions in the range of 25-80%.

US7973086 by Saxton et al. discloses a process in which a cobalt-based Fischer- Tropsch catalyst and an acid hydrotreating catalyst are arranged in alternating packed-beds along a tubular reactor. Under preferred embodiments, the process leads to a product hydrocarbon mixture in which the fraction of tail-gas hydrocarbons (C 4- ) contributes >34 wt% and the fraction of middle-distillates (given as C10-C21 in said document) accounts for <35 wt%, at a CO conversion of 25- 35%.

A process configuration in which a Fischer-Tropsch catalyst and the hydrotreating catalyst are operated in different compartments along one reactor vessel, as in those described in the aforementioned documents, might be a first approach to an individual adjustment of the reaction temperature. However, as evident from the ultimate hydrocarbon selectivities, the (hydro)cracking pattern of the hydrocarbons leaving the upstream bed of the Fischer-Tropsch catalyst, primarily n-paraffins, on the downstream hydrotreating catalyst under the syngas (CO-containing) atmosphere pertaining to this process is far from ideal. Generally severe hydrocarbon cracking converts not only the wax fraction but also the middle- distillates fraction of the Fischer-Tropsch products into lighter hydrocarbons, hence leading to an undesired high production of tail-gas hydrocarbons.

It has been suggested that a more desirable final product distribution could be achieved via the immediate processing of the most primary Fischer-Tropsch hydrocarbon products on the hydroprocessing catalyst by bringing both integrated catalysts in close spatial proximity, and hence reducing the transport distances for molecules between the active sites of the two catalysts. Freitez et al. "Single-Stage Fischer-Tropsch Synthesis and Hydroprocessing: The Hydroprocessing Performance of Ni/ZSM-5/Y-AI 2 O3 under Fischer-Tropsch Conditions" in Ind. Eng. Chem. Res., 50 (201 1 ), 13732-13741 , describes a process in which the particles of a cobalt-based Fischer-Tropsch catalyst and a Ni/ZSM-5/AI 2 O3 hydrotreating catalyst are blended and packed in a single bed in a tubular reactor, therefore achieving spatial proximities of a magnitude comparable to the size of the macroscopic particles of the blended catalysts, which typically ranges from hundreds of microns to millimeters, depending on the type of catalyst particles and the reactor hydrodynamics, and it is 2 mm in this particular document. Said blend of catalysts was applied in a process to convert a syngas stream (H 2 /CO=2) into liquid hydrocarbons in a single step. The process achieved the complete de-waxing of the hydrocarbon products, for which the contribution of C21 + hydrocarbons was lower than 5% (on a molar carbon basis). The process was particularly selective towards hydrocarbons in the naphtha range, achieving selectivities to hydrocarbons in the C5-C9 higher than 40 %. Nevertheless, the selectivity to the middle distillates fraction, given in the document as C10-C20, was relatively low (<15 %). In addition, the process led to a significant production of tail-gas hydrocarbons, with selectivities to C 4- exceeding 35 %.

Other documents disclose methods for the synthesis of "hybrid" solid catalysts in which the Fischer-Tropsch and the hydrotreating components are blended within the individual catalyst particles, e.g. pellets, extrudates, granules, achieving spatial proximities between the integrated catalytic functions in the nanometer and micrometer regimes. WO2014007598 by Su Ha et al. discloses a process in which a hybrid Fisher- Tropsch/hydrotreating catalyst prepared by growing a zeolite acid component within a porous cobalt oxide scaffold is employed to convert syngas to liquid hydrocarbons in a single step. Under disclosed preferred embodiments, the process did not achieve the complete de-waxing of the hydrocarbon products, for which the C-mol contribution of C22+ hydrocarbons exceeded 17%. Under preferred embodiments, the selectivity to tail-gas hydrocarbons (C 4- ) exceeded 25-30 %. Bao et al. "A Core/Shell Catalyst Produces a Spatially Confined Effect and Shape Selectivity in a Consecutive Reaction", in Angewandte Chemie Int. Ed. 47 (2007) 353-356, describes a hybrid catalyst in which a core microbead comprising a cobalt-based Fischer-Tropsch catalyst is enwrapped in an outer shell comprising BEA zeolite and the application of said catalyst in a process to convert a syngas stream (H 2 /CO=2) into liquid hydrocarbons in a single step. The process achieved the complete de-waxing of the hydrocarbon products, for which the C-mol contribution of C22+ hydrocarbons was null. The process was particularly selective towards hydrocarbons in the naphtha range, achieveing selectivities to hydrocarbons in the C5-C9 range as high as 53 % (on a molar carbon basis). Neverthless, the selectivity to the middle distillates fraction, given in the document as C10-C20, was relatively low (14.5 %). In addition, the process led to a significant production of tail-gas hydrocarbons, with selectivities to C 4- exceeding 30 %.

Sartipi et al. "Hierarchical H-ZSM-5-supported cobalt for the direct synthesis of gasoline-range hydrocarbons from syngas: Advantages, limitations, and mechanistic insight" in Journal of Catalysis 305 (2013) 179-190, describes a hybrid catalyst prepared by the incorporation of cobalt on a meso-microporous ZSM-5 (MFI) acid zeolite and the application of said catalyst in a process to convert a syngas stream (H 2 /CO=2) into liquid hydrocarbons in a single step. The process was particularly selective towards hydrocarbons in the naphtha range, achieving selectivities to hydrocarbons in the C 5 -Cn range as high as 50-60 % (on a molar carbon basis). Neverthless, the selectivity to the middle distillates fraction, given in the document as C12-C20, was relatively low (<10 %). In addition, the process led to a significant production of tail-gas hydrocarbons, with selectivities to C 4- exceeding 30 %. This document specifically points out some of the important negative effects which a close spatial intimacy between the integrated catalysts has on the ultimate product distribution, particularly as it boosts the production of light gas hydrocarbons via enhanced methanation and hydrogenolysis pathways on the Fischer-Tropsch active metal component of the hybrid catalysts.

US20100160464 by Kibby et al. discloses a process in which a hybrid Fischer- Tropsch/hydrotreating catalyst is produced by impregnating a zeolite-containing extrudate using a substantially non-aqueous solution of a cobalt precursor, targeting a limited interaction of the cobalt Fischer-Tropsch active phase with the acidic zeolite component, and said hybrid catalyst is employed to convert a syngas feed to liquid hydrocarbons in a single step. At a reaction temperature of 483 K, a reaction pressure of 10 atm, a syngas feed with a H 2 /CO molar ratio of 1 .6 is converted to a hydrocarbon product with a low contribution from tail-gas hydrocarbons (17.1 %, on a carbon molar basis) and a high contribution from hydrocarbons in the middle-distillates C10-C25 range (49%).

The inventors have considered that general limitations are associated to the integration of highly active, cobalt-based Fischer-Tropsch catalysts and acidic hydrotreating catalysts in close proximity. One first limitation relates to the fact that both catalysts need to operate at a common reaction temperature, while, rather different operation temperatures are individually desired for an optimal performance of the Fischer-Tropsch catalysts, particularly the most active ones which are based on metals such as cobalt or ruthenium as the major active phase, and the hydrotreating catalysts. Fisher-Tropsch catalysts provide best performances in the temperature range of 463-493 K, while hydrotreating catalysts require operation temperatures preferably in the range of 523-593K. It has been found by the inventors that operating both integrated catalysts in the Fischer- Tropsch temperature range leads to insufficient activity for the hydrotreating catalyst, resulting in incomplete de-waxing of Fischer-Tropsch products and accumulation of carbon deposits on the surface of the hydrotreating catalyst, resulting in a faster catalyst deactivation. To the contrary, the inventors found that the application of a common operation temperature in the range typically required by the hydrotreating catalyst boosts undesired methanation and water-gas-shift reactions on the Fischer-Tropsch catalyst and therefore a larger production of carbon dioxide and tail-gas hydrocarbon products which penalize the efficiency and economy of the process. In addition, processes in which the two catalysts are spatially intimate suffer from undesired mutual interactions between the two catalysts which further contribute to suboptimal catalytic performances. In particular, interaction of the Fischer-Tropsch active metal with the acid component of the hydrotreating catalyst is known to lead to very small (< 5 nm) and/or barely reducible Fischer-Tropsch species which promote the undesired formation of methane and other light gases via methanation and hydrogenolysis reaction pathways. In addition, migration of metal ions from the Fischer-Tropsch-active phase onto the acid sites of the concomitant hydrotreating catalyst, either during the preparation of the catalyst or promoted by the water under the hydrothermal conditions encountered in the reaction, results in the titration of the acidity in the latter, and therefore a premature deactivation of the hydrotreating functionality. According to the inventors, an additional important technical limitation of a close spatial intimacy of the two catalysts, either in the form of a hybrid catalyst or as a physical blend of catalyst particles, is the impossibility to perform pre-conditioning, rejuvenation and/or regeneration treatments individually for the Fischer-Tropsch and hydrotreating catalysts, as it would be desirable to individually optimize structural parameters such as the metal dispersion, and to adapt to the different rates of deactivation, and thereby different useful lifetimes, of the two catalysts.

The inventors considered that it would be very advantageous to develop a process which would circumvent these limitations of the state-of-the-art, allowing the operation of the two combined catalysts under individually optimized conditions, resulting in a better overall product distribution, for instance, uniting the wax- depletion in the ultimate hydrocarbon products with a lower contribution from the tail-gas fraction and a higher contribution from the middle-distillates fraction. Therefore, it is one object of the present invention to provide a process to convert synthesis gas into liquid hydrocarbons in a single step, i.e. with no intermediate product fractionation, separation or purification process step, in which the hydrocarbon products are essentially wax-free and additionally show a higher contribution from the fraction corresponding to middle distillates and a lower contribution from the fraction of tail-gas hydrocarbons. It is a further object of the present invention to provide a process in which the Fischer-Tropsch and hydrocracking solid catalysts can be placed spatially distant, i.e. not in direct physical contact, and operated under individually optimized reaction temperatures.

It is a further object of the present invention to provide a method in which the spatial compartmentalization of the two catalysts in different sections of one reactor vessel, or alternatively in different consecutive reactors (without any product separation/isolation unit operation in-between), allows the performance of conditioning, rejuvenation and regeneration treatments on each of the two solid catalysts at individually selected temperature, pressure, gas atmosphere and with individually selected time frequency.

It is still a further object of the present invention to provide a method to prepare a Fischer-Tropsch catalyst which can be applied in said process.

The inventors have developed a method to perform a process which combines a Fischer-Tropsch catalyst and a hydrotreating catalyst to produce liquid hydrocarbon products in a single step, without any intermediate product separation or isolation stage, which leads to a highly desirable hydrocarbon product with an unusually high contribution of the middle distillates fraction, and an unusually low contribution of tail-gas hydrocarbons.

More particularly, it has been found by the inventors that said desirable hydrocarbon product pattern can be achieved when the Fischer-Tropsch hydrocarbon products reaching the hydrotreating catalyst contain an unusually high proportion of olefins in the carbon chain-length range of C3-C10. The inventors have also discovered a method to prepare Fischer-Tropsch catalysts with bespoke porosities which extend over several length scales and owing to which, under standard operation conditions, said catalysts lead to an unexpected enrichment of the Fischer-Tropsch hydrocarbon products in olefins, while they additionally display a high activity per mass of metal, high selectivity to long-chain hydrocarbons and a very low production of undesired carbon dioxide. The unexpected Fischer-Tropsch product hydrocarbon distribution obtained with the inventive catalysts enables the process object of this invention as it allows the Fischer-Tropsch catalyst and the hydrotreating catalyst to operate spatially distant, in different sections of one reactor vessel or even in consecutive reactor units, at different reaction temperatures which can be adjusted individually, while the hydrocarbon stream exchanged between both catalysts corresponds to a very primary Fischer-Tropsch product, and hence resembles the case where the two catalysts are spatially very intimate. It has been discovered that such effect is responsible for a more desirable overall hydrocarbon product distribution which unites the depletion of waxes with a notably higher contribution from hydrocarbons in the middle distillate range and a notably lower contribution from hydrocarbons in the tail-gas range.

The present invention accordingly provides, in a first aspect, a process by means of which a syngas feedstock is converted into liquid hydrocarbons in a single step by the combination of a solid Fischer-Tropsch catalyst and a solid hydrotreating catalyst in which said catalysts are operated spatially distant, in different sections of a tubular reactor vessel or in consecutive reactors, without any intermediate product fractionation, separation or purification process step,, the Fischer-Tropsch catalyst is located upstream and the hydrotreating catalyst is located downstream of the former, the hydrocarbon stream leaving the upstream catalyst displays an unusually high content in olefins in the C3-C10 carbon chain length range and the final hydrocarbon products leaving the downstream catalyst display a desirable distribution. The present invention additionally provides a method to prepare a Fischer-Tropsch catalyst with a multimodal porosity, which can be applied in said process.

DESCRIPTION The present invention is concerned, in a first aspect, with a process for the conversion of syngas mixtures into liquid hydrocarbons in a single step, i.e. with no intermediate product fractionation, separation or purification process step,, in which a Fischer-Tropsch catalyst displaying an unusual product selectivity is combined with an acidic hydrotreating catalyst.

Throughout the description and claims, the word "comprises" and its variants do not aim to exclude other technical characteristics. For a person skilled in the art, other objects, advantages and characteristics of the invention will be partially inferred from the description and partially from the implementation of the invention.

It has been deemed essential for the process of this invention that the combined Fischer-Tropsch and hydrotreating catalysts are not in direct physical contact and therefore can operate at different, individually selected reaction temperatures, albeit under essentially the same pressure. According to one embodiment of the invention, the Fischer-Tropsch and the hydrotreating catalysts are located in different packed beds along a tubular reactor with two differentially heated zones, being the Fischer-Tropsch catalyst located upstream and the hydrotreating catalyst downstream. Under operation conditions, the gas stream leaving the packed bed containing the Fischer-Tropsch catalyst, i.e. the stream which contains the Fischer-Tropsch products along with unconverted syngas, flows directly to the packed bed containing the hydrotreating catalyst, without any product fractionation, isolation or purification unit operation in between. In another possible embodiment of the present invention, the two combined catalysts are located in two different sub-units of a compact reactor or micro-reactor vessels, whose temperature can be controlled independently, being the Fischer-Tropsch catalyst located upstream and the hydrotreating catalyst located downstream, without any product fractionation, isolation or upgrading unit operation in between both subunits of the reactor vessel. In yet another possible embodiment of the present invention, the two catalysts are placed in two different reactor vessels, connected in series, whose temperature can be controlled independently, and being the Fischer-Tropsch catalyst loaded into the reactor vessel located upstream and the hydrotreating catalyst loaded into the reactor vessel located downstream, without any product fractionation, isolation or purification unit operation in between both reactors.

According to one embodiment of the invention, the spatial compartmentalization of the Fischer-Tropsch and hydrotreating catalysts in different reactor sub-units, or different reactors, allows their connection in series, during periods of time in which the syngas feed is being converted consecutively on both catalysts, but it also enables an operation in parallel, in which each catalyst compartment is set to receive a different gas feed under selected pressure and temperature conditions, in order to submit either one or the two catalysts to individually designed treatments of pre-conditioning, rejuveneation, re-generation or to carry out the partial or total renovation of one or the two catalysts. Once said treatment is completed, the different sub-units of one reactor vessel, or the different reactor vessels, containing each of the combined catalysts can be connected back in series, under an essentially common operation pressure and individually adjusted operation temperatures, to receive the syngas stream which is thus converted into liquid hydrocarbons.

According to another embodiment, the spatial compartmentalization of the Fischer- Tropsch and hydrotreating catalysts in different reactor sub-units, or different reactor vessels, enables to perform said individual catalyst treatments and operations in a mode which is known as "swing mode" in the art, and thus without interrupting the continuous process of conversion of the syngas feed stream into hydrocarbons.

Thus, the present invention comprises the following embodiments:

A Fischer-Tropsch-Catalyst (FT-catalyst) with a multimodal porosity,

having an active metal selected from Co, Fe, Ru or mixtures thereof on a a high surface area support selected from S1O2, T1O2, AI2O3, hydrated precursors or any mixture thereof,

having a surface area in the range of between 10 and 1 100 m 2 /g, preferably between 50 and 400 m 2 /g; having a particle size in the range of 200 μηη to 800 μητι, preferably 300 μηη to 700 μητι, more preferably 400 μιτι to 600 μm and

having pores in a pore size distribution, with a first maximum in the mesopore range of 2 to 50 nm and with a second maximum in the macropore range of above 50 nm, whereby the percentage of mesopores is in the range of 20 to

95 %, preferably 50 to 95 %, of the total pore volume, and the percentage of macropores is in the range of 5 to 80 %, preferably 5 to 40 %, of the total pore volume. According to the present invention and its examples, specific surface area shall be determined by nitrogen physisorption at the liquid nitrogen boiling point at atmospheric pressure (77 K) after drying the solid material (ca. 100 mg, 0.4-0.6 mm particle size) at 523 K under vacuum for 10 h. The specific surface area shall be determined using the B.E.T method in the relative pressure (P/Po) regime of 0.05-0.30 of the adsorption branch of the isotherm, where Po is the vapor pressure of nitrogen at the temperature of the measurement.

According to the present invention and its examples, total pore volume and pore size distributions shall be determined by mercury intrusion porosimetry after drying the sample (0.4-0.6 mm particle size) at 383 K for 72 h. The intrusion-extrusion isotherms shall be recorded at room temperature in the pressure range of 6.9- 10 4 - 4.1 10 4 Pa with an equilibration rate of 0.1 μΙ- g "1 s ~1 . For the determination of pore diameter and volume, a geometrical pore model shall be considered, assuming a Hg density of 13.55 g cm "3 and a contact angle of 141 degrees. Pores shall be denoted according to their diameter following the lUPAC recommendations, i.e. micropores for diameters smaller than 2 nm, mesopores for diameters in the range 2-50 nm and macropores for diameters larger than 50 nm. Accordingly, total macropore volume shall be defined as the cumulative pore volume corresponding to pores with diameters larger than 50 nm as determined by the method described above.

According to the present invention and its examples, the range of catalyst particle size shall be defined be the opening size of standard stainless steel sieves tested according to the ISO 3310 norm, between which more than 80% of the catalyst mass is retained after a sieving procedure.

A FT-Catalyst with a multimodal porosity as defined before, wherein the macropores are present in a distribution with a first maximum in the range of 50 to 200 nm and a second maximum in the range of 200 nm to 10 μιτι, whereby the percentage of macropores of 50 to 200nm is in the range of 40 to 95 %, preferably 70 to 95 %, of the total macropore volume, and the percentage of macropores of 200 nm to 10 μηη is in the range of 5 to 60 %, preferably 5 to 20 %, of the total macropore volume.

A FT-Catalyst with a multimodal porosity as defined before, obtainable by a process comprising the steps of:

a. Preparing a suspension containing water, a dispersible alumina source and optionally an acid substance, wherein the alumina source is preferably selected from the group of hydragillite, bayerite, pseudoboehmite, amorphous gels, transition aluminas which comprise at least one phase taken from the group comprising rho, chi, eta, gamma, kappa, theta and alpha phases;

b. Adding an organic polymer substance to the suspension obtained in step a), which polymer is preferably a non-ionic surfactant selected from the group which comprises:

i) alkyl-polyethylene oxides, also known as polyethoxilates, such as those pertaining to the family of surfactants commercialized under the name of Tergitol 15-S- with general formula R-O(EO) x H where R is a hydrophobic alkyl group with n carbon atoms, where n typically spans in the range from 1 to at least 20, EO represents an ethylene oxide building unit (OCH 2 CH 2 ) with x ranging from about 7 to 40;

ii) alkyl-phenyl polyethylene oxides; such as those pertaining to the family of surfactants commercialized under the name of Igepal-RC or Triton-X;

iii) polyethylene oxide (PEO) -polypropylene oxide (PPO) block-copolymers; such as those pertaining to the family of surfactants commercialized under the name Pluronic, having a formula (EO) m -(PO) 0 -(EO)p with m and p being independently in the range of 2-130 and o being in the range of 15-70; iv) polysorbate-type surfactants formed by the ethoxylation of sorbitan followed by the addition of lauric acid, such as those pertaining to the family of surfactants commercialized under the names Polysorbate, Alkest or Tween; and combinations thereof, more preferably a non-ionic surfactant of the alkyl- polyethylene oxide type, also known as polyethoxylates, such as those pertaining to the family of surfactants commercialized under the name of Tergitol 15-S- with general formula R-O(EO) x H where R is a hydrophobic alkyl group with n carbon atoms, where n typically spans in the range from 1 to at least 20, EO represents an ethylene oxide building unit (OCH 2 CH 2 ) with x ranging from about 7 to 40; and which polymer is solid or preferably liquid at ambient conditions;

c. Subjecting the suspension obtained in step b) to a hydrothermal treatment under autogenous pressure in an autoclave, preferably in a temperature range from 300 K to 400 K, more preferably from 330 to 350 K, preferably over a time span from 12 h to 72, more preferably from 40 to 60 h;

d. Depressurizing the autoclave and drying the product obtained in step c) until the water content is below 10 wt%;

e. Thermally treating the dried product of step d) at an elevated temperature up to 1000 K under oxidizing conditions, preferably under air, whereby the hydrocarbon polymer is combusted in the dried product of step d) and the product of step d) is calcined;

f. Impregnating the product of step e) with a solution of at least one salt of an active metal selected from Co, Ru and Fe, preferably according to the incipient wetness method, drying the impregnated product and submitting it to a preferably thermal treatment to decompose said metal salt into a metal oxide or the corresponding metallic form.

A device for converting a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) into liquid hydrocarbons, comprising:

a. a FT-catalyst as defined before,

b. a Hydrotreating catalyst (HT-catalyst), preferably in the form of a metal or a metal sulphide dispersed in the form of nanoparticles on particles of an acidic solid, which is preferably selected from an amorphous S1O2-AI2O3, a zeolite (crystalline aluminosilicate) or an acidic zeotype,

c. an inlet for the feed stream, and

d. an outlet for the hydrocarbons, water and carbon dioxide byproducts and unconverted syngas,

wherein the FT-catalyst and the HT-catalyst are contained in separate compartments (units) of the device which compartments are in fluid communication with each other and where the HT-compartment is positioned downstream of the FT-compartment, preferably in a spatial distance sufficient to establish a temperature difference between the two catalysts of at least 20 K.

A process for converting a syngas feed stream comprising carbon monoxide and hydrogen as major components into liquid hydrocarbons, making use of said device, whereby

- a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) with a molar H 2 /CO ratio in the range of 0.5-3, preferably in the range of 1 -2, is provided to the inlet of a device according to claim 4 and further directed to the FT-catalyst operated at a reaction temperature range selected in the range of 423-513 K, preferably in the range of 460 to 500 K,

- the obtained gas mixture is directed to the HT-catalyst operated at a reaction temperature range selected in the range of 483-623 K, preferably in the range of 503-553 K, and

- the obtained gaseous hydrocarbon mixture is directed to a collection vessel, whereby the operating temperature of the FT-catalyst is lower than the operating temperature of the HT-catalyst, and

whereby the syngas space velocity is selected to achieve a CO conversion in the range of 5-100%, preferably in the range from 20-80%.

The use of a FT-catalyst as defined before for converting a feed stream comprising carbon monoxide and hydrogen as major components (synthesis gas) into liquid hydrocarbons. By the inventive process, the FT catalyst of the invention is suitable to achieve the beneficial technical effect of the process of the invention, which leads, under standard FT reaction conditions, to a product mixture with a minimum content of olefins in the C3-C10 hydrocarbon fraction, as mentioned several times in the spec. This aspect is the foundation of the invention.

In the inventive device, the distance between the two compartments can be, depending on the size of the device, just a few cm up to several hundreds of meters and all the way to km. The main requirement is that the distance is sufficient so that taking into account the thermal conduction properties of the vessels (or vessel subunits) were the catalysts are operated, the temperature of the catalysts can be controlled independently. In our experiments, the catalysts are only ca. 4 cm away from each other. In a plant, the catalysts could be km away from each other as long as there is no further catalytic conversion and no product fractionation, isolation or purification in between FT-catalyst and HT-catalyst. In addition, the distance is to be defined in the direction of the feedstock flow. The catalysts could be placed on both sides of a micrometer thick stainless steel plate in a microreactor, i.e. very close to each other physically, although without direct contact. Thus, the "temperature" difference can be used to define the spatial distance. If the catalysts need to work at a temperature difference of at least e.g. 20K, this sets already a minimum requirement for their spatial distance.

According to the process of the present invention, a syngas mixture with a molar H 2 /CO ratio in the range of 0.5-3, preferably in the range of 1 -2, is used as feedstock.

According to the process of the present invention, the final product stream leaving the hydrotreating catalyst has a weight contribution from carbon dioxide lower than 3 wt%, and preferably lower than 1 wt%, on the basis of all carbon-containing reaction products.

According to the process of the present invention, the final product stream leaving the hydrotreating catalyst has a weight contribution from solid hydrocarbons, e.g. C25+ lower than 5 wt%, and preferably lower than 2 wt%, based on the total hydrocarbon products.

According to the process of the present invention, the final product stream leaving the hydrotreating catalyst has a weight contribution from the tail-gas hydrocarbons (C 4- ) lower than 25 wt%, preferably lower than 20 wt%, along with a weight contribution from hydrocarbons in the carbon number range of C10-C25 larger than 40%, preferably larger than 45 wt%, based on the total hydrocarbon products. Particularly none of the prior art references achieves the combined results displayed by the process of the invention, such as a very low selectivity to tail-gas hydrocarbons (let alone as low as 18 wt%) along with a very high selectivity to hydrocarbons in the middle-distillates range (let alone as high as 49 wt% to hydrocarbons in the range of C10-C25) in conjunction with a high CO conversion rate, very low production of CO2 and the achievement of an essentially wax-free hydrocarbon product mixture (let alone a C25+ selectivity as low as 2 wt%), while the two combined solid catalysts are not in direct contact and are operated at individually adjustable reaction temperatures. It has been deemed essential for the process of the present invention that the gas stream leaving the Fischer-Tropsch catalyst, constituting the feed stream to the hydrotreating catalyst located downstream, displays an unusually high content in olefin Fischer-Tropsch products, as a result of a limited secondary processing of the most primary Fischer-Tropsch products within the particles of the catalyst were they are produced. Without wishing to be bound by any theory, the inventors believe that a high fraction of C3-C10 olefins in the hydrocarbon mixture which reacts on the hydrotreating catalyst under a syngas atmosphere is essential to achieve an efficient de-waxing of the Fischer-Tropsch hydrocarbons while preventing any extensive cracking of Fischer-Tropsch hydrocarbons in the middle distillates range and avoiding the production of light tail-gas hydrocarbons, resulting in the highly desirable ultimate hydrocarbon product distribution pertaining to the process of the invention. The composition of the hydrocarbons produced in a given Fischer-Tropsch catalyst, and therefore sent as feed onto a hydrocracking catalyst according to the process of the present invention, can be adequately determined by means of catalytic tests in which the Fischer-Tropsch catalyst is tested alone, without any additional catalyst, for the conversion of a syngas feed stream under reaction conditions which are standard for the industrial operation for the Fischer-Tropsch synthesis, and the corresponding product stream analyzed, for instance by gas chromatography analytical methods, as a function of the reaction conditions and the degree of CO conversion per reactor pass. According to the present invention, under standard reaction conditions for the Fischer-Tropsch synthesis of hydrocarbons, the Fischer-Tropsch catalyst produces a hydrocarbon product stream with an unusually high concentration of olefins in the carbon chain length range of C3-C10. According to one embodiment of the invention, the weight fraction of C 5+ hydrocarbons in the FT products is higher than 80 wt%, and the weight ratio of alpha-olefin to n-paraffin products in the carbon chain length range of C3-C10 is higher than 0.5, and more preferably higher than 0.75, when a syngas feedstock with a H 2 /CO molar ratio of 2.0 is processed at a reaction temperature of 483 K, a reaction pressure of 20 bar and a gas space velocity leading to a CO conversion of 30±5 % per reactor pass.

In the process of the invention, the pressure can be selected in the range of 5 to 200 bar, preferably in the range of 5-50 bar. The Fischer-Tropsch catalyst operates at a reaction temperature which can be selected in the range of 423-513 K, preferably in the range of 460 to 500 K . The hydrotreating catalyst operates at a reaction temperature which can be selected in the range of 483-623 K, preferably in the range of 503-553 K. The syngas space velocity can be selected to achieve a CO conversion in the range of 5-100%, preferably in the range from 20-80%. In a second aspect, the present invention provides also a method to prepare a Fischer-Tropsch catalyst with original physicochemical and catalytic properties which enable the process of the invention. Said inventive Fischer-Tropsch catalyst should display a high specific activity under standard Fischer-Tropsch reaction conditions. Preferably this activity, expressed as a mass-specific rate of CO conversion, is equal or higher than 10 mmolco g ca t h ~1 , and more preferably higher than 20 mmolco g ca t h ~1 , at an operation temperature of 483 K using a syngas feed with a molar H 2 /CO ratio of 2. A high specific activity is desired for process intensification.

The inventive Fischer-Tropsch catalyst should display a limited activity for the water-gas-shift reaction, hence the selectivity to CO2 (per reactor pass) preferably does not exceed 3 wt%, and most preferably does not exceed 1 wt%. A very low per-pass production of CO2 is desirable to maximize the efficiency of the CO conversion process and avoid the need for extensive recycle streams and additional reverse-water-gas-shift unitary operations, hence contributing to process intensification, a lower overall energy requirement and a lower overall carbon footprint of the process.

The inventive Fischer-Tropsch catalyst should additionally display an unusually high selectivity to alpha-olefin primary products under standard Fischer-Tropsch reaction conditions. In a preferred embodiment, the weight content of alpha-olefins products in the hydrocarbon chain length range of C3-C10 is higher than 25 wt% when a syngas feedstock with a nominal H 2 /CO molar ratio of 2.0 is processed at a reaction temperature of 483 K, a reaction pressure of 20 bar and a CO conversion of 30±5 % is achieved per reactor pass, which are standard reaction conditions for the Fischer-Tropsch synthesis. More preferably, the weight content of alpha-olefin products in the hydrocarbon chain length range of C3-C10 is higher than 45 wt% when a syngas feedstock with a nominal H 2 /CO molar ratio of 2.0 is processed at a reaction temperature of 483 K, a reaction pressure of 20 bar and a CO conversion of 30±5 % is achieved per reactor pass. In a preferred embodiment of the invention, the Fischer-Tropsch catalyst is a supported metal catalyst. The concept of "supported metal catalyst" is understood in the art as a catalyst composition comprising a catalytically active metal part, dispersed in the form of particles with an average diameter typically smaller than 100 nm (nanoparticles), which is therefore active, or can be converted into an active phase in situ prior to or during the usage of the catalyst, and a catalytically non-active part, wherein the catalytically non-active part, denoted as carrier or support material in the art, is generally porous and forms the majority of the catalyst on a mass bases. In a preferred embodiment of the present invention, the Fischer-Tropsch catalyst comprises cobalt as the major Fischer-Tropsch active part, dispersed in the form of particles on a porous carrier material which does not contribute to the Fischer-Tropsch catalytic activity. Preferably, the weight loading of cobalt, i.e. the weight fraction of the total catalyst which corresponds to cobalt in said catalyst, is in the range of 5-50 wt%, and more preferably in the range of 10- 30 wt%.

The porous carrier material should be chemically stable under the severe hydrothermal reaction conditions encountered in a process of syngas conversion into hydrocarbons. Said porous carrier can be an oxide selected among those oxide porous carriers which are employed as support materials for supported metal catalysts in the art, and which can comprise, but it is not limited to, AI2O3, S1O2, T1O2, or combinations thereof. Alternatively, the support material can be based on a carbide or oxy-carbide material such as SiC, SiO x C y . Alternatively, the support material can be based on carbon. Alternatively, the support material can be a composite incorporating a combination of said materials.

The pore modality, pore diameter and pore volume of the inventive Fischer- Tropsch catalyst have been deemed particularly significant for the process of the invention. The porosity of a solid material can be determined in the art by analytical methods such as nitrogen physisorption combined to suitable mathematical models for the analysis of the physisorption isotherms, thermometry combined to suitable mathematical models for the analysis of the corresponding scanning calorimetry profiles, mercury intrusion porosimetry combined to suitable mathematical models for the analysis of the intrusion isotherms or by electron microscopy methods such as transmission electron microscopy, scanning electron microscopy and their tomographic variations which allow imaging in the three directions in space, combined with suitable methods for quantification of said porosity. According to the lUPAC, pores are denoted micropores when their diameter is smaller to 2nm, they are denoted mesopores if their diameter is in the range of 2-50 nm and they are denoted macropores if their diameter is larger than 50 nm. Macropores can thus lay in the nanometer regime if their diameter is in the 50-1000 nm range or in the micrometer regime if their diameter exceeds 1000 nm (1 micrometer).

The Fischer-Tropsch catalyst according to the invention has a specific surface area ranging between 10 and 1 100 m 2 /g, preferably between 50 and 400 m 2 /g. A Fischer-Tropsch catalyst according to the present invention displays at least two modes of pores: one in the mesopore regime and one in the macropore regime. Yet more preferably, the Fischer-Tropsch catalyst displays at least three modes of pores: one in the mesopore regime and two in the macropore regime, one of which consists of macropores with average diameter in the nanometer regime and the other one consists of macropores with an average diameter in the micrometer regime. The multimodal porosity facilitates the evacuation of primary hydrocarbon products from the catalyst pores under standard operation conditions, preventing more effectively the secondary processing of the most primary alpha-olefin products and increasing their contribution up to unusual contents in the hydrocarbon stream produced on the Fischer-Tropsch catalyst and further processed on the hydrotreating catalyst.

In one embodiment of the invention, the total pore volume of the Fischer-Tropsch catalyst is at least 0.3 cm 3 g "1 , preferably at least 0.8 cm 3 g ~1 . Preferably, the mesopores of the catalyst have an average diameter in the range of 5-40 nm, and most preferably in the range of 5-20 nm. Said average mesopore diameter is preferred to confine and stabilize cobalt nanoparticles of a diameter in the range of 6-12 nm, which according to what is known in the art, provide high CO conversion rates per unit mass of metal. Preferably, the macropores of the Fischer-Trospch catalyst account for a fraction of the total pore volume of at least 5 %, and more preferably of at least 20%. According to one embodiment of the present invention, the porosity of the Fischer- Tropsch catalyst becomes dictated primarily by the support material, being the contribution of the active metal component to the total porosity negligible, aside from the corresponding mass dilution effect on mass-specific porosity parameters, i.e. those expressed per unit total mass of catalyst.

The support material of the Fischer-Tropsch catalyst of the invention can be obtained by a method which involves:

a) in a first step, the preparation of a suspension containing water, a dispersible alumina source and optionally an acid substance. The alumina source employed to prepare the suspension, is preferably selected from the list of hydragillite, bayerite, pseudoboehmite, amorphous gels, transition aluminas which comprise at least one phase taken from the group comprising rho, chi, eta, gamma, kappa, theta and alpha phases. More preferably, said alumina source is a high-purity dispersible pseudoboehmite, for example Disperal® commercialized by Sasol. Preparation of the suspension is accomplished for instance by mechanical stirring or ultrasound stirring;

b) in a second step the addition of a polymer to the suspension. Said polymer can be solid or liquid at ambient conditions, and is preferentially liquid at ambient conditions;

c) in a third step, subjecting the suspension to a hydrothermal treatment under autogenous pressure;

d) in a fourth step, depressurizing and drying the material until the water content is below 10 wt%;

e) in a fifth step the application of a thermal treatment under an oxidizing, preferably air, atmosphere to crystallize the alumina precursor and combust the organic material in the dried solid. The person skilled in the art will know alternative methods to prepare solid materials with multimodal porosities, in the mesopore and macropore regimes, which could also be suitable to prepare a Fischer-Tropsch catalyst for the process of the invention. These methods include the use of solid combustive porogen materials in combination with peptization, extrusion or granulation methodologies, followed by selective removal of the porogen, for instance by calcination or selective dissolution, coagulation methods, methods in which an emulsion is employed as porogen agent, methods in which ice or an alternative frozen substance is employed as porogen agent and removed by freeze drying.

During or after the synthesis of the support material, additional treatments known in the art might be applied to increase the crush strength of the material. The crush strength might be increased via partial sintering of the constituents after high temperature treatments. Alternatively, the crush strength might be increased by the incorporation of binder or reinforcement materials.

Supported metal catalysts can be synthesized by applying a suitable metal precursor on the support material, followed by suitable methods to decompose said precursor into the species which is responsible for the catalytic activity. Examples of cobalt containing precursors are inorganic and organic cobalt salts, cobalt clusters, and cobalt organometallic complexes. Representative of these compounds are cobalt nitrate, cobalt chloride, cobalt sulphate, cobalt phosphate, cobalt chloroplatinate, cobalt hydroxide, cobalt acetate, cobalt acetylacetonate, cobalt oxalate, cobalt oleate, cobalt citrate, cobalt carbonyl, and the like. Cobalt precursors can provide cobalt in a zero oxidation state, II oxidation state, III oxidation state, or a combination thereof. According to a preferred embodiment of the invention, the Fischer-Tropsch catalyst is prepared using cobalt nitrate as cobalt precursor. Several methods are known in the art to incorporate the active metal part on a support material. These methods comprise preparation techniques such as impregnation, deposition precipitation, ion exchange, electrochemical deposition, electrostatic adsorption, co-precipitation which are known methods in the art. The documents "Handbook of Heterogeneous Catalysis", G. Ertl, H. Knoezinger, F. Schuth, J. Weitkamp (Editors); volume 1 , Wiley-VCH Verlag GmbH & Co. Weinheim, 2008 and "Synthesis of solid catalysts", K. P. de Jong (Editor); Wiley- VCH Verlag GmbH & Co. Weinheim, 2009 provide good references for the existing methods to incorporate the active metal part on a support material. In a preferred embodiment of the invention, cobalt is incorporated on the support material by impregnation using a liquid solution of the cobalt precursor in a suitable solvent. Preferably, said solvent is selected from the list comprising water, methanol, ethanol, ether, acetone or combinations thereof. More preferably said solvent is water.

It is customary in the art, that supported metal catalysts comprise so-called promoters, in addition to the main active metal part and the support material. In general, a promoter is a substance that enhances the catalyst's performance in terms of any of activity, selectivity to a given product or fraction of products, stability under the operation conditions, or combinations thereof. In one preferred embodiment of the invention, the Fischer-Tropsch catalyst comprises at least one metal promoter which assists the reduction of cobalt species and which is selected form the list of ruthenium, rhenium, platinum, palladium, silver, gold, copper, preferably form the list of ruthenium, rhenium, platinum, palladium, and more preferably from the list of ruthenium, rhenium, platinum. The weight content of this promoter is preferably lower than 10 wt%, on the basis of the total mass of catalyst, and more preferably lower than 5 wt%. In one embodiment of the invention, the Fischer-Tropsch catalyst comprises at least one promoter element which adds to the stability of the support material under the hydrothermal conditions encountered in the Fischer-Tropsch synthesis reaction. Said promoter element can be selected from the list of alkali metals, alkaline earth metals, lanthanides, transition metals, boron, aluminium, gallium, indium, carbon, silicon, germanium, tin, nitrogen, phosphor, arsenic, antimony, and any combination thereof. Any of these elements can be either in elementary form or in ionic form. In one preferred embodiment of the invention, the Fischer-Tropsch catalyst comprises at least one promoter element which contributes to a higher selectivity to olefin Fischer-Tropsch products under standard reaction conditions for the Fischer-Tropsch synthesis. Said promoter element can be selected from the list of alkali metals, alkaline earth metals, lanthanides, yttrium, scandium, titanium, zirconium, chromium, manganese, iron, zinc, gallium, boron, indium, germanium, tin, phosphor, sulfur, and any combination thereof. Any of these elements can be either in elementary form or in ionic form. According to the process of the invention, the stream leaving the Fischer-Tropsch catalyst, which contains the unconverted syngas as well as the Fischer-Tropsch products, is sent on a hydrotreating solid catalyst where part of the primarily linear hydrocarbons generated on the Fischer-Tropsch catalyst are further processed by catalytic reactions which comprise oligomerization, hydride transfer, (hydro)isomerization and/or (hydro)cracking.

According to one preferred embodiment of the invention, the hydrotreating catalyst comprises a metal promoter and an acidic component. Said acid component can be selected from materials such as amorphous silica-alumina, tungstated zirconia, zeolites or a non-silicoaluminate zeotypes. Without wishing to be bound by any theory, the inventors believe that one hydrotreating catalyst in which the acidic component is active for the reaction of oligomerization of short-chain olefins (C2- C 4 ) is preferred to attain a more desirable ultimate hydrocarbon product distribution, as short-chain olefin oligomerization reactions contribute a net chain- growth pathway which reduces the selectivity to tail-gas hydrocarbons. In a preferred embodiment of the invention, the acidic component of the hydrotreating catalyst is a zeolite classified as "medium-pore" according to the IZA. The statement "medium pore" as used herein means having a crystallographic free diameter in the range of from about 3.9 to about 7.1 Angstrom when the zeolitic material is in the calcined form. The crystallographic free diameters of the channels of molecular sieves are published in the "Atlas of Zeolite Framework Types", Fifth Revised Edition, C H. Baerlocher, W. M. Meier, and D. H. Olson (Editors), Elsevier, Amsterdam, 2001 . Preferably said zeolite component is selected from the list of zeolite topologies comprising MFI, FER, MWW, TON, MTT, MTW, MEL, EMT, IMF, TUN. More preferably the zeolite has a MFI topology (trade name ZSM-5). As known by the person skilled in the art, one particularly important physicochemical characteristic of zeolites in what relates to their acidity, hydrophilia/hydrophobia and catalytic properties is the atomic ratio of Si to Al (Si/AI) in their composition. In a preferred embodiment of the invention, the zeolite component of the hydrotreating catalyst is relatively hydrophobic as it displays a Si/AI atomic ratio greater than 20, and more preferably greater than 30. It is also known by the person skilled in the art that the average size of the microporous domains within the zeolite catalysts has a significant influence on its catalytic performance as well as on the metal dispersion achievable at a given metal content in the case of hydrotreating catalysts additionally incorporating a dispersed metal component. In this context the statement "microporous domains" refers to those regions within the zeolite crystals which comprise exclusively pores in the micropore size regime, i.e. < 2 nm in diameter. Such "microporous domains" are delimited by larger pores in the mesopore or macropore regimes in the case that the zeolite crystals display multiple pore modes, or by the outer boundary of the individual zeolite crystals in the case of zeolites which are entirely microporous and hence do not display intra-crystal meso- or macropores. In a preferred embodiment of the invention, the average size of the microporous domains in the zeolite acid component of the hydrotreating catalyst is smaller than 500 nm, and more preferably smaller than 100 nm.

Typically, the hydrotreating catalyst incorporates a metal component dispersed in the form of nanoparticles on the acidic component. These components are usually added as a metal precursor salt by methods which are known in the art, such for instance impregnation, deposition precipitation, ion exchange, electrochemical deposition, electrostatic adsorption, co-precipitation. The documents "Handbook of Heterogeneous Catalysis", G. Ertl, H. Knoezinger, F. Schuth, J. Weitkamp (Editors); volume 1 , Wiley-VCH Verlag GmbH & Co. Weinheim, 2008 and "Synthesis of solid catalysts", K. P. de Jong (Editor); Wiley-VCH Verlag GmbH & Co. Weinheim, 2009 provide good references for the existing methods to incorporate the active metal part on a support material. After incorporation of the metal precursor, this can be thermally converted to the corresponding oxide in an oxidizing atmosphere and reduced to the metallic state using hydrogen or an alternative reducing agent. The metal promoter is typically a metal or combination of metals selected from Group VIII noble and non-noble metals, Group 1 B coinage metals, and Group VIB metals. Noble and coinage metals which can be used include platinum, palladium, rhodium, ruthenium, osmium, silver, gold and iridium, or any combination thereof. In a preferred embodiment of the present invention, the nature of the metal component is selected to bind carbon monoxide strongly under the typical operation conditions of the hydrotreating catalyst in the process of the invention. Without wishing to be bound by any theory, the inventors believe that partial inhibition of the hydrogenation catalytic activity of the metal component in the hydrotreating catalyst by strong adsorption of carbon monoxide from the syngas unconverted on the upstream Fischer-Tropsch catalyst contributes to the preservation of an unusually high partial pressure of olefins in the reaction medium, hence enabling their beneficial technical effect on the ultimate hydrocarbon product distribution. In a preferred embodiment of the invention, said metal component is selected from the list of platinum and platinum-containing multimetallics.

In the process of the invention, the catalysts may be present within the reactor as pellets, spheres, extrudates, irregular shaped granules, coated monoliths, etc, of various possible sizes, depending of the type of reactor and the fluid-solid dynamics experienced in said reactor. In a preferred embodiment of the invention, the Fischer-Trospch catalyst is present as particles in the size range of 50-1000 micrometers, and more preferably in the size range of 50-500 micrometers, a size which is suitable for compact tubular milli-reactors. In another preferred embodiment of the invention, the Fischer-Tropsch catalyst is present as a layer coated on the outer surface of a monolithic substrate or a micro-reactor module.

Prior to their use in catalysis, the catalysts might be subjected to thermal treatments in the presence of hydrogen or an alternative reducing agent to render their metal components into the metallic state. In a preferred embodiment, said reduction treatment takes place at a temperature in the range of 473-873K, and more preferably in the range of 573-773K. Said reduction treatment can be performed in situ, i.e. once the catalysts have been loaded into the reactor.

The present invention will now be described in more detail by means of the following drawings and examples which are provided by way of illustration and do not in any way limit the invention. DESCRIPTION OF DRAWINGS

Drawing 1. Pore size distribution as determined by mercury intrusion porosimetry for a gamma-AI 2 O3 porous support material for the synthesis of a Fischer-Tropsch catalyst according to one embodiment of the present invention. Drawing 2. Pore size distribution as determined by mercury intrusion porosimetry for a commercial gamma-AI 2 O3 porous support material representative of those employed for the synthesis of Fischer-Tropsch catalysts according to state of the art procedures. EXAMPLES

The following methods for determining the properties of materials as prepared and used in the following Examples are employed: Macropore and mesopore size distributions, as well as total macropore volumes were determined by means of mercury intrusion porosimetry in a Micromeritics AutoPore IV 951 apparatus. In a typical experiment, 80-150 mg of sample (0.4-0.6 mm) were dried at 383 K for 72 h before the measurement. The intrusion-extrusion isotherms were recorded at room temperature in the pressure range of 6.9·10 4 - 4.1 ·10 4 Pa with an equilibration rate of 0.1 μΙ_ g "1 s ~1 . For the determination of pore diameter and volume, a geometrical pore model was considered, with a Hg density of 13.55 g cm "3 and a contact angle of 141 °. Micropore volume, mesopore volume and specific surface area were determined by means of nitrogen physisorption. Nitrogen physisorption isotherms were recorded at 77K using a Micromeritics ASAP instrument after degassing the sample (ca. 100 mg, 0.4-0.6 mm particle size) at 523 K under vacuum for 10 h. Surface areas were derived using the B.E.T method in the relative pressure (P/Po) regime of 0.05-0.30. Total micropore volumes were determined by the t-plot method in the statistical thickness range of 3.5-5 Angstroms.

The macroscopic particle size of the catalysts was adjusted and determined using calibrated Retsch solid stainless steel sieves tested according to the ISO 3310 norm. The particle size range was defined as the opening size of the two sieves between which more than 80% of the catalyst particles were retained.

The cobalt metal loading in the catalysts was determined by means of hydrogen temperature-programmed reduction (H 2 -TPR) in a Micromeritics Autochem 2910 device. In a typical experiment, about 100 mg of sample were initially flushed with Ar flow (50 cm 3 min "1 ) at room temperature for 30 min, then the gas was switched to 10 vol% H 2 in argon (Ar) and the temperature increased up to 1 123 K at a heating rate of 10 K min "1 . A downstream 2-propanol/dry ice trap was used to retain the water generated during the reduction. The H 2 consumption rate was monitored in a thermal conductivity detector (TCD) previously calibrated via the injection of known volumes of hydrogen using a gas syringe. The cobalt loading was determined form the total hydrogen consumption assuming all cobalt to be present as Co3O 4 in the calcined catalysts, i.e. prior to the H 2 -TPR experiment, and full reduction to metallic cobalt, which results in a reduction stoichiometric H 2 /Co molar ratio of 4/3. The hydrogen consumption associated to the Ru promoter was considered negligible.

Example I

Synthesis of a Fischer-Tropsch catalyst according to the invention

In one particular embodiment of the present invention, a ruthenium-promoted cobalt-based Fischer-Tropsch catalyst was synthesized as follows. High-purity dispersible nano-boehmite (75% AI 2 O3, Sasol) was used as precursor and a polyethyleneglycolether non-ionic surfactant (Tergitol 15-S-7, Sigma-Aldrich) was employed as porogen to synthesize the gamma-AI 2 O3 support. First, a synthesis gel was prepared by dispersing the nano-boehmite precursor in a solution of the surfactant in Dl water to achieve a final gel molar composition of AI :EO:H 2 O 1 :1 1 .5:49, where EO represents the ethylenoxide building units in the polymer (ca. 7 mol EO/mol surfactant). The gel was stirred vigorously at room temperature using a laboratory vertical stirrer (450 rpm) for 5 hours, transferred into a polypropylene autoclavable bottle and treated hydrothermally at 343 K in an oven for 48 h. The resulting gel was transferred into an evaporation dish and let dry at 343 K for 72 hours in an oven with internal air circulation. Finally, the solid was transferred into a muffle oven, dried at 393 K for 3h, and then heated to 813 K (0.5 K min "1 ) for the crystallization of gamma-AI 2 O3 and the combustion of the organic porogen. The muffle oven is equipped with convective air-extraction as required to rapidly evacuate volatile organic material and avoid the generation of igniting gas mixtures in the chamber. After calcination, the solid was sieved and the 0.4-0.6 mm fraction was further employed. Analysis of the porosity of the calcined material using mercury intrusion porosimetry revealed three defined levels of porosity (drawing 1 shows the corresponding pore diameter distribution), one first level of porosity in the range of mesopores (2-50 nm in diameter), peaking at ca. 9 nm, and two additional levels of porosity in the range of macropores (>50 nm in diameter), one in the nanometer regime, peaking at ca. 100 nm, and the other one in the macrometer regime, peaking at ca. 3 micrometers. On this bespoke support material, metal species were incorporated by impregnation. The support material was first dried under vacuum (423 K) for 4 hours before impregnation under static vacuum with an aqueous solution containing Co(NO3) 2 -6H 2 O (3.4 M) and ruthenium (III) nitrosyl nitrate (Ru/Co=0.02, atomic) and further acidified with a 0.25 vol% HNOs(conc). The volume of solution applied was equivalent to the total mesopore volume of the support material as determined by N 2 physisorption. After impregnation, the solid was dried at 343 K under N 2 flow (200 cm 3 g ca t "1 min "1 ) for 10 hours and the nitrate metal precursors further decomposed by calcination at 623 K for 3h under N 2 flow (heating rate of 2 K min "1 ). The impregnation and calcination steps were repeated to achieve a cobalt weight loading of 20.8 wt% in the final catalyst. Example II

Synthesis of a reference Fischer-Tropsch catalyst on a commerciaiiy available support material following state of the art procedures

By way of comparison to the state of the art, one ruthenium-promoted cobalt- based Fischer-Tropsch catalyst was synthesized as follows. Commercial high- purity gamma-AI 2 O3 microgranules (Sasol Materials, Germany) were sieved and the 0.4-0.6 mm fraction was further employed as support materials. Analysis of the porosity of the calcined material using mercury intrusion porosimetry revealed one single level of porosity (drawing 2 shows the corresponding pore diameter distribution), in the range of mesopores (2-50 nm in diameter), peaking at ca. 9 nm. On this commercial support material, metal species were incorporated by impregnation. The support material was first dried under vacuum (423 K) for 4 hours before impregnation under static vacuum with an aqueous solution containing Co(NO 3 ) 2 -6H 2 O (3.4 M) and ruthenium (III) nitrosyl nitrate (Ru/Co=0.02, atomic) and further acidified with a 0.25 vol% HNOs(conc). The volume of solution applied was equivalent to the total mesopore volume of the support material as determined by N 2 physisorption. After impregnation, the solid was dried at 343 K under N 2 flow (200 cm 3 g ca t "1 min "1 ) for 10 hours and the nitrate metal precursors further decomposed by calcination at 623 K for 3h under N 2 flow (heating rate of 2 K min "1 ). The impregnation and calcination steps were repeated to achieve a cobalt weight loading of 20.0 wt% in the final catalyst.

Example III

Synthesis of a hydrocracking catalyst according to state of the art procedures

A hydrocracking catalyst was synthesized by impregnation of a commercial nano- crystalline H-ZSM-5 zeolite (MFI structure, Si/AI = 32, Clariant) with an aqueous solution of Pt(NH 3 ) (NO 3 ) 2 followed by drying in an oven at 323 K and calcination under air flow at 623 K in a tubular oven. The Pt loading as determined by quantitative Energy Dispersion X-ray (EDX) spectroscopy in a S-3500 N (Hitachi) Scanning Electron Microscope was 0.6 wt%. Example IV

Synthesis of a reference hybrid Fischer-Tropsch/hydrotreating catalyst

By way of reference to the state of the art, one hybrid catalyst composed of both a Fischer-Tropsch and a hydrotreating catalyst in very close intimacy, blended at the single catalyst particle (pellet) level was prepared as follows. High-purity dispersible nano-boehmite (75% AI2O3, Sasol) was used as precursor for gamma- AI2O3. A commercial nanocrystalline H-ZSM-5 zeolite (MFI structure, Si/AI = 32, Clariant) was used as acid component for the hybrid catalyst. The dispersible nano-boehmite and the nanocrystalline H-ZSM-5 zeolite were co-suspended in deionized water (4.8 g nano-boehmite, 10 g H-ZSM-5, 180 ml_ Dl water). The suspension was stirred vigorously in a polypropylene bottle at room temperature using a laboratory vertical stirrer (450 rpm) while heated to 343 K and let dry overnight in an oil bath. The dried composite material (support) was grinded in a mortar and calcined at 623 K for 5h. The calcined composite was pelletized at 80 bar and sieved between 0.4-0.6 mm. The Fischer-Tropsch/hydrotreating composite catalyst was then prepared by incipient wetness impregnation of said pre-sieved support material. The support was first dried under vacuum (423 K) for 4 hours before impregnation under static vacuum with an aqueous solution containing Co(NO 3 )2-6H 2 O (2.4 M), ruthenium (III) nitrosyl nitrate (Ru/Co=0.02, atomic), Pt(NH 3 ) (NO 3 )2 (0.05 M) and further acidified with a 0.25 vol% HNOs(conc). The volume of solution applied was equivalent to the total mesopore volume of the support as determined by N 2 physisorption. After impregnation, the solid was dried at 343 K under N2 flow (200 cm 3 g ca t " 1 min "1 ) for 10 hours and the nitrate metal precursors further decomposed by calcination at 623 K for 3h under N 2 flow (heating rate of 2 K min "1 ).

Example V

Catalytic testing of Fischer-Tropsch catalysts under industrially relevant conditions

In a general comparison method, the Fischer-Tropsch catalyst prepared according to Example I, in accordance to the present invention, was tested under reaction conditions representative of an industrial Fischer-Tropsch process. The reaction experiment was performed in a 316L stainless-steel packed-bed tubular reactor (12 mm inner diameter). Gas feeds, i.e. H 2 (99.999%, Air Liquide) and a premixed syngas mixture (CO:H 2 :Ar 3:6:1 , Ar as internal standard for chomatography, from Air Liquide) were fed using calibrated mass flow controllers (Bronkhorst). The catalyst particles (400-600 μιτι) were blended and diluted with SiC (350-560 μιτι, grit 46) granules and loaded into the reactor to achieve a constant packed-bed volume of 6.5 cm 3 . A closed capillary sheathing two thermocouples was axially inserted in the bed enabling independent temperature reading and control at the upper and bottom halves of the catalyst bed. Prior to catalysis, the catalyst was reduced at atmospheric pressure under H 2 flow (200 mL min "1 ) at 673 K for 8 h. After reduction, the reactor was cooled to 423 K and the gas flow was switched to syngas. After 5 min, the system was pressurized to the reaction pressure of 20 bar, which was further controlled during the reaction experiments using a membrane dome pressure regulator (GO regulator). Next, the reactor temperature was slowly and stepwise increased to the desired reaction temperature (0.5 K min " 1 to 453 K followed by 0.1 K min "1 to 483 K). The syngas WHSV was adjusted in the range of (1 -5 gCO g ca t "1 h "1 ), in order to achieve a pre-set CO conversion of 30±5 % in the pseudo-steady state, reached after >30 h on-stream, and characterized by CO conversion variations of < 0.2% h "1 . Downstream of the tubular reactor two consecutive cold traps were set at temperatures of 423 and 373 K, respectively, at the reaction pressure, to collect heavy hydrocarbon products and part of the produced water. The rest of all pipelines downstream of the reactor were kept at a temperature of 443 K to prevent condensation. The lighter fraction of hydrocarbons leaving the traps was depressurized in the dome pressure controller and analyzed online by gas chromatography (GC). The trapped hydrocarbons were collected, separated from the water fraction and weighed. An aliquot fraction was then diluted in n-heptane (HPLC grade) and analyzed offline by GC. Reported activity and product selectivity results correspond to the pseudo- steady state, reached after > 30 h on-stream, and characterized by CO conversion variations of < 0.2% h "1 .

Example VI

In a general comparison method, the Fischer-Tropsch catalyst prepared according to Example II, hence not in accordance to the present invention, was tested under reaction conditions representative of an industrial Fischer-Tropsch process. Aside from the different catalyst employed, the reaction experiment was performed as described in Example V. The performances of the Fischer-Tropsch catalyst prepared according to the present invention (Example I) and a comparative catalyst prepared by state of the art procedures on a commercially available support material (Example II) are compared in Table 1 . Table 1

1 Mass ratio of alpha-olefin to paraffin (O/P) for hydrocarbon products with the corresponding chain-length. As observed from the results presented in Table 1 , a Fischer-Tropsch catalyst prepared according to the present invention (Example V) produces a hydrocarbon product stream with a similar chain-length distribution but a notably higher alpha- olefin to paraffin mass ratio in the hydrocarbon chain length range of C3-C10 than a Fischer-Tropsch catalyst prepared, for comparative purposes, on a commercially available support material (Example VI) following state-of-the-art procedures.

Example VII

Catalytic testing of Fischer-Tropsch catalysts in integration with a hydrotreating catalyst for the direct production of liquid hydrocarbons from synthesis gas

In a general comparison method, the Fischer-Tropsch catalyst prepared according to Example I, hence according to the present invention, was integrated with a hydrotreating catalyst prepared according to Example III, and tested for the direct conversion of syngas to liquid hydrocarbons. Both catalysts were blended and loaded into a single packed bed in a tubular reactor, a process configuration not in accordance to the present invention and presented for reference purposes. The reaction experiments were performed in a 316L stainless-steel packed-bed tubular reactor (12 mm inner diameter). Gas feeds, i.e. H 2 (99.999%, Air Liquide) and a premixed syngas mixture (CO:H 2 :Ar 3:6:1 , Ar as internal standard for chomatography, from Air Liquide) were fed using calibrated mass flow controllers (Bronkhorst). The particles (400-600 μιτι) of the Fischer-Tropsch catalyst were blended with the required amount of the particles (400-600 μιτι) of the hydrotreating catalyst, the resulting blend further diluted with SiC (350-560 μιτι, grit 46) granules and loaded into the reactor to achieve a constant packed-bed volume of 6.5 cm 3 . A closed capillary sheathing two thermocouples was axially inserted in the bed enabling independent temperature reading and control at the upper and bottom halves of the catalyst bed. Prior to catalysis, the catalysts were reduced at atmospheric pressure under H 2 flow (200 mL min "1 ) at 673 K for 8 h. After reduction, the reactor was cooled to 423 K and the gas flow was switched to the above mentioned syngas mixture. After 5 min, the system was pressurized to the reaction pressure of 20 bar, which was further controlled during the reaction experiments using a membrane dome pressure regulator (GO regulator). Next, the reactor temperature was slowly and stepwise increased to the desired reaction temperature using heating rates of: 0.5 K min "1 to 453 K followed by 0.1 K min "1 to the final reaction temperature of 523 K. The syngas weight hourly space velocity (WHSV) was adjusted in the range of (1 -5 g CO g ca t "1 h "1 ), in order to achieve a pre-set CO conversion level of 30±5% in the pseudo steady state, reached after > 30 h on-stream, and characterized by CO conversion variations of < 0.2% h ~1 . The mass ratio of the Fischer-Tropsch and the hydrotreating catalyst was selected to achieve an overall ratio between the molar flow of carbon in the Fischer-Tropsch products generated per pass in the reactor and the mass of hydrotreating catalyst of 0.075 mol C h "1 g ca t "1 - Downstream of the tubular reactor two consecutive cold traps were set at temperatures of 423 and 373 K, respectively, at the reaction pressure, to collect heavy hydrocarbon products and part of the produced water. The rest of all pipelines downstream of the reactor were kept at a temperature of 443 K to prevent condensation. The lighter fraction of hydrocarbons leaving the traps was depressurized in the dome pressure controller and analyzed online by gas chromatography (GC). The trapped hydrocarbons were collected, separated from the water fraction and weighed. An aliquot fraction was then diluted in n- heptane (HPLC grade) and analyzed offline by GC. Reported activity and product selectivity results correspond to the pseudo-steady state, reached after > 30 h on- stream, and characterized by CO conversion variations of < 0.2% h ~1 .

Example VIII

In a general comparison method, the Fischer-Tropsch catalyst prepared according to Example II, hence not according to the present invention, was integrated with a hydrotreating catalyst prepared according to Example III, and tested for the direct conversion of syngas to liquid hydrocarbons. Both catalysts were blended and loaded into a single packed bed in a tubular reactor, a process configuration not in accordance to the present invention and presented for reference purposes. Aside from the fact that a different Fischer-Tropsch catalyst was employed, the reaction experiment was performed as described in Example VII.

Example IX

In a general comparison method, the hybrid Fischer-Tropsch/hydrotreating catalyst prepared according to Example IV, hence not according to the present invention, was tested for the direct conversion of syngas to liquid hydrocarbons. The catalyst was loaded into a single packed bed in a tubular reactor, a process configuration not in accordance to the present invention and presented for reference purposes. Aside from the fact that the hybrid catalyst was employed, instead of a blend of Fischer-Tropsch and hydrotreating catalysts, the reaction experiment was performed as described in Example VII.

Example X

Catalytic testing of Fischer-Tropsch catalysts in combination with a hydrotreating catalyst for the direct production of liquid hydrocarbons from synthesis gas

In a particular embodiment of the present invention, the Fischer-Tropsch catalyst prepared according to Example I, hence according to the present invention, was combined with a hydrotreating catalyst prepared according to Example III, and tested for the direct conversion of syngas to liquid hydrocarbons. Each catalyst was placed in a different, and spatially distant packed bed along a tubular reactor, enabling independent control of the working temperature for each of the catalysts, a process configuration in accordance to one of the embodiments of the present invention.

The reaction experiment was performed in a 316L stainless-steel packed-bed tubular reactor (12 mm inner diameter). Gas feeds, i.e. H 2 (99.999%, Air Liquide) and a premixed syngas mixture (CO:H 2 :Ar 3:6:1 , Ar as internal standard for chomatography, from Air Liquide) were fed using calibrated mass flow controllers (Bronkhorst). The particles (400-600 μιτι) of the hydrotreating catalyst prepared according to Example III were diluted with SiC (350-560 μιτι, grit 46) granules and loaded into a packed bed at the bottom half of the reactor. The particles (400-600 μιτι) of the Fischer-Tropsch catalyst were diluted with SiC (350-560 μιτι, grit 46) granules and loaded as a separate packed bed at the upper half or the reactor bed, upstream from the packed bed containing the hydrotreating catalyst. Both catalyst packed-beds were had a constant volume of 4 cm3, were held by means of plugs of quartz wool and spaced at least 4 cm. A closed capillary sheathing two thermocouples was axially inserted through the center axis of both beds. The tips of the thermocouples were placed corresponding with the overall center of both packed-beds, enabling independent temperature control on the two catalysts. Prior to catalysis, the catalysts were reduced at atmospheric pressure under H2 flow (200 ml_ min "1 ) at 673 K for 8 h. The same temperature was set for both beds during the reduction pre-treatment. After reduction, the reactor was cooled to 423 K and the gas flow was switched to the above mentioned syngas mixture. After 5 min, the system was pressurized to the reaction pressure of 20 bar, which was further controlled during the reaction experiments using a membrane dome pressure regulator (GO regulator). Next, the reactor temperature was slowly and stepwise increased to the desired reaction temperature using heating rates of: 0.5 K min "1 to 453 K followed by 0.1 K min "1 to the final reaction temperature, which was 483K and 523 K for the upper bed and bottom beds, respectively. The syngas weight hourly space velocity (WHSV) was adjusted in the range of (1 -5 g CO g ca t " 1 h "1 ), in order to achieve a CO in the range of 50±15%. The mass ratio of the Fischer-Tropsch and the hydrotreating catalyst were selected to achieve an overall ratio between the molar flow of carbon in the Fischer-Tropsch products generated per pass in the reactor and the mass of hydrotreating catalyst of 0.075 mol C 1 h "1 g ca t " 1 - Downstream of the tubular reactor two consecutive cold traps were set at temperatures of 423 and 373 K, respectively, at the reaction pressure, to collect heavy hydrocarbon products and part of the produced water. The rest of all pipelines downstream of the reactor were kept at a temperature of 443 K to prevent condensation. The lighter fraction of hydrocarbons leaving the traps was depressurized in the dome pressure controller and analyzed online by gas chromatography (GC). The trapped hydrocarbons were collected, separated from the water fraction and weighed. An aliquot fraction was then diluted in n-heptane (HPLC grade) and analyzed offline by GC. Reported activity and product selectivity results correspond to the pseudo-steady state, reached after > 30 h on- stream, and characterized by CO conversion variations of < 0.2% h "1 .

Example XI

Catalytic testing of Fischer-Tropsch catalysts in combination with a hydrotreating catalyst for the direct production of liquid hydrocarbons from synthesis gas

In a general comparison method, the Fischer-Tropsch catalyst prepared according to Example II, hence not according to the present invention, was combined with a hydrotreating catalyst prepared according to Example III, and tested for the direct conversion of syngas to liquid hydrocarbons. Each catalyst was placed in a different, and spatially distant packed bed along a tubular reactor, enabling independent control of the working temperature for each of the catalysts. Aside from the fact that a Fischer-Tropsch prepared according to the comparative Example II was employed, the reaction experiment was performed as described in Example X.

The performances of the Fischer-Tropsch catalyst prepared according to the present invention (Example I) and a comparative catalyst prepared by state of the art procedures on a commercially available support material (Example II) in integration to a hydrotreating catalyst (Example III), according to the process of the invention as well as comparative process configurations not pertaining to the invention, are summarized in Table 2.

Table 2

Syngas weight space velocity based on the total mass of the two catalysts.

Weight fraction of n-paraffin in the corresponding product slate.

3 Operation temperature of the upstream Fischer-Tropsch catalyst.

4 Operation temperature of the downstream hydrotreating catalyst.

As observed from the results presented in Table 2, a Fischer-Tropsch catalyst prepared according to the present invention, and integrated with a hydrotreating catalyst in a process configuration according to the present invention, i.e. with both catalysts operated in a spatially compartmentalized fashion and with individual temperature control (Example X), leads to an ultimate hydrocarbon product distribution with a significantly higher (54-96% higher) contribution from hydrocarbons in the middle-distillate range (C10-C25) and a significantly lower (36- 47% lower) contribution from tail-gas hydrocarbons (C 4- ) than either alternative process configurations or the same process configuration employing comparative Fischer-Tropsch catalysts or hybrid Fischer-Tropsch/hydrotreating catalysts not prepared according to the present invention.