WO2014207096A1 - Method for manufacturing shaped beta-sic mesoporous products and products obtained by this method - Google Patents

Method for manufacturing shaped beta-sic mesoporous products and products obtained by this method Download PDF

Info

Publication number
WO2014207096A1
WO2014207096A1 PCT/EP2014/063503 EP2014063503W WO2014207096A1 WO 2014207096 A1 WO2014207096 A1 WO 2014207096A1 EP 2014063503 W EP2014063503 W EP 2014063503W WO 2014207096 A1 WO2014207096 A1 WO 2014207096A1
Authority
WO
Grant status
Application
Patent type
Prior art keywords
mesoporous
carbon
nm
sic
catalyst
Prior art date
Application number
PCT/EP2014/063503
Other languages
French (fr)
Inventor
Patrick Nguyen
Charlotte Pham
Michel Kartheuser
Christophe VIEVILLE
Peter Jacobus Van Berge
Original Assignee
Sicat
Sasol Technology (Pty) Limited
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10GCRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G2/00Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon
    • C10G2/30Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon from carbon monoxide with hydrogen
    • C10G2/32Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon from carbon monoxide with hydrogen with the use of catalysts
    • C10G2/33Production of liquid hydrocarbon mixtures of undefined composition from oxides of carbon from carbon monoxide with hydrogen with the use of catalysts characterised by the catalyst used
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J23/00Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
    • B01J23/70Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
    • B01J23/74Iron group metals
    • B01J23/75Cobalt
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/002Catalysts characterised by their physical properties
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/1004Surface area
    • B01J35/101410-100 m2/g
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/1004Surface area
    • B01J35/1019100-500 m2/g
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/1033Pore volume
    • B01J35/1038Pore volume less than 0.5 ml/g
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/1033Pore volume
    • B01J35/10420.5-1.0 ml/g
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/1052Pore diameter
    • B01J35/10612-50 nm
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/1052Pore diameter
    • B01J35/106650-500 nm
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J35/00Catalysts, in general, characterised by their form or physical properties
    • B01J35/02Solids
    • B01J35/10Solids characterised by their surface properties or porosity
    • B01J35/108Pore distribution
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B35/00Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
    • C04B35/515Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics
    • C04B35/56Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides
    • C04B35/565Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide
    • C04B35/573Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on non-oxide ceramics based on carbides or oxycarbides based on silicon carbide obtained by reaction sintering or recrystallisation
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0022Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors
    • C04B38/0032Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof obtained by a chemical conversion or reaction other than those relating to the setting or hardening of cement-like material or to the formation of a sol or a gel, e.g. by carbonising or pyrolysing preformed cellular materials based on polymers, organo-metallic or organo-silicon precursors one of the precursor materials being a monolithic element having approximately the same dimensions as the final article, e.g. a paper sheet which after carbonisation will react with silicon to form a porous silicon carbide porous body
    • CCHEMISTRY; METALLURGY
    • C10PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10GCRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
    • C10G3/00Production of liquid hydrocarbon mixtures from oxygen-containing or organic materials, e.g. fatty oils, fatty acids
    • C10G3/42Catalytic treatment
    • C10G3/44Catalytic treatment characterised by the catalyst used
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J27/00Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
    • B01J27/20Carbon compounds
    • B01J27/22Carbides
    • B01J27/224Silicon carbide
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01JCHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J37/00Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
    • B01J37/08Heat treatment
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2111/00Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
    • C04B2111/00474Uses not provided for elsewhere in C04B2111/00
    • C04B2111/0081Uses not provided for elsewhere in C04B2111/00 as catalysts or catalyst carriers
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30Constituents and secondary phases not being of a fibrous nature
    • C04B2235/34Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3418Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30Constituents and secondary phases not being of a fibrous nature
    • C04B2235/42Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
    • C04B2235/422Carbon
    • C04B2235/424Carbon black
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30Constituents and secondary phases not being of a fibrous nature
    • C04B2235/42Non metallic elements added as constituents or additives, e.g. sulfur, phosphor, selenium or tellurium
    • C04B2235/428Silicon
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30Constituents and secondary phases not being of a fibrous nature
    • C04B2235/48Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/52Constituents or additives characterised by their shapes
    • C04B2235/528Spheres
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54Particle size related information
    • C04B2235/5409Particle size related information expressed by specific surface values
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/50Constituents or additives of the starting mixture chosen for their shape or used because of their shape or their physical appearance
    • C04B2235/54Particle size related information
    • C04B2235/5418Particle size related information expressed by the size of the particles or aggregates thereof
    • C04B2235/5427Particle size related information expressed by the size of the particles or aggregates thereof millimeter or submillimeter sized, i.e. larger than 0,1 mm
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74Physical characteristics
    • C04B2235/76Crystal structural characteristics, e.g. symmetry
    • C04B2235/762Cubic symmetry, e.g. beta-SiC
    • CCHEMISTRY; METALLURGY
    • C04CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04BLIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/80Phases present in the sintered or melt-cast ceramic products other than the main phase
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P30/00Technologies relating to oil refining and petrochemical industry
    • Y02P30/20Bio-feedstock

Abstract

Method for manufacturing a β-SiC shaped piece comprising mesopores with a diameter of between 6 nm and 100 nm representing a mesopore volume (determined by mercury intrusion porosimetry) greater 0.35 cm3/g, said method comprising the transformation of a mesoporous carbon preform with at least one silicon source into silicon carbide (β-SiC), said silicon source being able to be incorporated in said preform or contributed from outside, said carbon preform having mesopores with a diameter of between 6 nm and 100 nm with a mesopore volume greater than 0.35 cm3 per gram of carbon. This β-SiC mesoporous shaped piece can be used as a catalyst carrier for chemical reactions involving a liquid phase, and in particular for the Fischer-Tropsch reaction.

Description

Method for manufacturing shaped beta-SiC mesoporous products and products obtained by this method

Technical field of the invention

The invention concerns the field of heterogeneous catalysis and in particular carriers for a heterogeneous silicon carbide catalyst. It also concerns more particularly the field of shaped β-SiC products obtained by the shape-memory synthesis methods. Prior art

A catalyst is a material that increases the conversion and selectivity of a chemical reaction and is intact at the end of the reaction. Heterogeneous catalysis is the method in which the reagents are adsorbed on the surface area of the catalytic solid, are activated by chemical interactions with the surface area of the catalyst, and are rapidly and selectively transformed into adsorbed products that then desorb from the surface of the catalyst. Typically a heterogeneous catalyst comprises a carrier (also called support) on which an active phase is dispersed. The active phase of the heterogeneous catalyst often consists of metals, metal oxides, sulphides or carbides. The carriers often consist of porous solids that are oxides, such as alumina and silica, or carbon. It is preferable to have the active phase finely divided on the surface of the carrier in order to increase the surface exposed to reagents. This is made possible by the presence of pores in the carrier that will increase the specific surface area of the solid. Micropores (defined by lUPAC, see Pure & Applied Chemistry, 66, n° 8, pages 1739-1758 (1994) as pores with a diameter of less than 2 nm) greatly increase the specific surface area. One example is activated carbon, which is exclusively microporous and may have a specific surface area greater than 1000 m2/g. In heterogeneous catalysis, mesoporous and microporous carriers are preferred. Mesopores (diameter of between 2 nm and 50 nm according to lUPAC) give rise to specific surface areas from several tens of m2/g to several hundreds of m2/g. Macropores are considered not to provide significant specific surface area or very little.

In order to maximise the reaction rate, it is essential to maximise the accessibility for all reagents to the active sites, which are dispersed through the internal structure of the pores (mesopores). In heterogeneous catalysis, a catalytic action is generally broken down into seven steps:

(i) external diffusion: transfer of external mass or film where the reagents present in a stagnant film that surrounds the solid must penetrate the solid;

(ii) internal diffusion: the reagents diffuse in the pores to the active sites; (iii) adsorption of the reagent (or reagents) A on the surface of the catalyst;

(iv) reaction: transformation of A to B on catalytic sites (active site);

(v) desorption of the product (or products) B from the surface of the catalyst;

(vi) internal diffusion: the products diffuse from the pores to the surface of catalyst; (vii) external diffusion: transfer of external mass or film.

Steps (i), (ii), (vi) and (vii) are diffusion processes only slightly dependent on temperature (in T1/2 or T3/2) whereas steps (iii), (iv) and (v) are chemical processes greatly dependent on temperature. By increasing the temperature, the reaction rate will increase exponentially and the limiting steps will become the diffusion steps. The diffusion being related to the size of the grains and to the size and number of pores, it is preferable to have wide pores interconnected so as to reduce the diffusion factor. It is therefore preferable to have a non-microporous catalytic material. More particularly, a catalyst carrier having mesopores and macropores is preferred. The mesopores will contain the finely dispersed catalytic phase (a catalytic material) and the macropores will make it possible to bring the reagents to the mesopores and to discharge the products out of the solid after reaction. According to the l UPAC classification, mesopores are pores having a diameter of between 2 nm and 50 nm. More details on the elementary concepts of heterogeneous catalyst are published in the second edition of the book "Fundamentals of Industrial Catalytic Processes" by C H Bartholomew and R J Ferrauto (2006).

One carrier material for catalysts is silicon carbide; its applications in industrial processes are in the course of development and are dependent on mastery of its pore distribution. The pore distribution depends on the method of producing the material.

A method for obtaining a catalyst carrier based on β-SiC in the form of granules with a BET specific surface area of at least 5 m2/g is known from the patent US 6,184,178 (Pechiney Recherche). These granules are obtained by shaping a mixture of a carbonisable thermosetting resin or pitch with an Si and/or Si02 powder and optional additives. The additives may be activated carbon, crosslinking agents, porogens, plasticisers, lubricants or solvents. The crosslinking of the resin takes place at a temperature of up to 250°C. The heat treatment aimed at carbonising the organic material and the carburising is carried out at a temperature of between 1300°C and 1450°C. The patent EP 0 624 500 B1 describes a similar method leading to a product that has a very low mesoporosity consisting of pores the size of which is centred very precisely on a range of diameters between 27.5 nm and 35 nm. The article "Innovative porous SiC-based materials: From nanoscopic understandings to tunable carriers serving catalytic needs" by P Nguyen and C Pham, which appeared in Applied Catalysis A: General 391 (201 1 ) 443-454, describes the preparation of porous catalyst carriers of β-SiC of various forms such as: pellets, rings, granules, foams, microballs.

Moreover, there is known from the patent US 7,910,082 (Corning Inc.) a method for obtaining ordered mesoporous carbon-silicon nanocomposites by an auto-assembly induced by evaporation of a precursor composition that preferably comprises a phenolic resin, a prehydrolysed tetraethyl-orthosilicate (TEOS), a surfactant and butanol. The precursor mixture is dried, crosslinked and heated in order to form an ordered mesoporous silicon carbide having a specific surface area of between 400 m2/g and 900 m2/g and a mean pore size not exceeding 6 nm, determined according to the nitrogen adsorption measurement and the BJH method. The BJH (Barrett-Joyner-Halenda) method is a method for calculating the distribution of the pore size in a porous material using adsorption or desorption isotherms. This method does not take into account pores with a diameter significantly greater than 100 nm. The pores are produced by the auto-assembly of a tri-block polymer in the phenolic resin /TEOS/butanol mixture, and their size is limited. The patent CN 1 401 564 describes a method for obtaining a mesoporous β-SiC powder with a specific surface area of between 60 m2/g and 120 m2/g and pores of a size between 3 nm and 50 nm. This material is obtained by a method in which a phenolic resin is dissolved in a solvent, with the addition of a salt of a transition metal, ethylsilicate (or methyl- or propylsilicate) and a mineral acid, and then the silicate is hydrolysed, a crosslinking agent is added and the solid obtained is subjected to heat treatment at a temperature of between 1200°C and 1400°C for 5 hours to 24 hours. The SiC material that results therefrom is in the form of a powder and is contaminated by the transition metal that was added as a porogen: the SiC must therefore be washed in order to eliminate this transition metal. As described in the patent, the method leads to a powder. As catalyst carriers should be made from a shaped material, powders must be shaped before being usable in a catalytic method, and there is a risk of loss of desirable porosity during this shaping operation.

The β-SiC materials obtained by these methods have a high specific surface area. They are suitable as a catalyst carrier for certain gaseous-phase reactions, in which the contact time between the reaction medium and catalyst is generally very short. For example, the use of such catalyst carriers has been described for the selective oxidation of H2S in sulphur and for the Fischer-Tropsch synthesis (see the aforementioned article by P Nguyen and C Pham), or for the treatment of diesel engine exhaust gases (see the aforementioned EP 0 624 560 B1 , see also WO 2005/038204), or for the production of hydrogen by the oxidation of methane (see WO 2004/007074). The applicant has found that methods according to the prior art do not make it possible to obtain optimised products for certain liquid-phase catalysis applications or under gaseous- phase conditions liable to lead to the condensation of relatively heavy molecules. The transport conditions being different in gaseous phase and liquid phase, it is not surprising that the same catalyst carrier is not perfectly suited to the two media at the same time. Novel β-SiC catalyst carriers are therefore sought which are able to be prepared in different geometric forms, which have a sufficient specific surface area and pore size and which better suit liquid-phase reactions.

Subject matter of the invention

The applicant has realised that a simple increase in the specific surface area does not improve the suitability of materials based on β-SiC as a catalyst carrier for heterogeneous catalysis, in particular with a view to the formation of heavy molecules; the formation of heavy molecules may be either sought in the catalytic method in which carriers based on β-SiC are used, as in the document US 5,576,466 (Pechiney Recherche), which describes the isomerisation of mixtures of Cio to C20 hydrocarbons, or inevitable, as in the case of the Fischer-Tropsch reaction (see WO 2012/038621 (CNRS), WO 2012/164231 (SICAT), see also WO 2007/000506 and WO 2005/073345 (TOTAL)). In all these cases a question is posed as to the porosity actually accessible to a viscous phase under reaction conditions involving heavy molecules and high pressures. This is the motivation for seeking novel carriers for heterogeneous catalysis.

According to the invention, the problem is solved by mesoporous β-SiC catalyst carriers with a particular porous structure and distribution. More precisely, these shaped materials, that can be prepared as shaped pieces, have pores with a diameter of between 6 nm and

100 nm corresponding to a mesopore volume of at least 0.35 cm3/g, preferably at least 0.40 cm3/g and even more preferentially at least 0.45 cm3/g (determined by mercury intrusion porosimetry). Shaped materials and shaped pieces according to the invention are accessible by a novel method for manufacturing a β-SiC catalyst carrier, which forms a first subject matter of the present invention. In this method a mesoporous β-SiC shaped material or shaped piece is obtained using a mesoporous carbon preform. More precisely, the first subject matter of the invention is a method for manufacturing a β- SiC shaped material or shaped piece comprising mesopores with a diameter of between 6 nm and 100 nm representing a mesopore volume greater than 0.30 cm3/g and preferably greater than 0.35 cm3/g, and even more preferentially greater than 0.40 cm3/g (determined by mercury intrusion porosimetry), said method comprising the transformation of a mesoporous carbon preform with at least one silicon source into silicon carbide (β- SiC), said silicon source being able to be incorporated in said preform and/or contributed from outside, said transformation taking place in a non-oxidising atmosphere at a temperature preferably lying between 1 100°C and 1400°C, said mesoporous carbon preform having mesopores with a diameter of between 6 nm and 100 nm with a mesopore volume greater than 0.25 cm3 per gram of carbon (preferably greater than 0.35 cm3 per gram of carbon, and even more preferentially greater than 0.45 cm3 per gram of carbon). By way of example, it is possible to manufacture a β-SiC shaped material or shaped piece comprising mesopores with a diameter of between 6 nm and 100 nm representing a mesopore volume greater than 0.30 cm3/g, preferably greater than 0.35 cm3/g, from a mesoporous carbon preform having mesopores with a diameter of between 6 nm and 100 nm with a pore volume greater than 0.25 cm3 per gram of carbon, and preferably greater than 0.30 cm3 per gram of carbon and even more preferentially greater than 0.35 cm3 per gram of carbon. Still by way of example, it is possible to manufacture a β-SiC shaped piece having mesopores with a diameter of between 6 nm and 100 nm representing a mesopore volume greater than 0.35 cm3/g and preferably greater than 0.40 cm3/g, from a mesoporous carbon preform having mesopores with a diameter of between 6 nm and 100 nm with a pore volume greater than 0.30 cm3 per gram of carbon, and preferably greater than 0.35 cm3 per gram of carbon, and even more preferentially greater than 0.40 cm3 per gram of carbon.

In an advantageous embodiment, the method according to the invention comprises the steps of

(a) pyrolysis of a preform of a mesoporous carbon precursor comprising at least one silicon source for obtaining a mesoporous carbon preform containing silicon;

(b) transformation of said mesoporous preform into mesoporous β-SiC by reaction with materials comprising silicon in a non-oxidising atmosphere at a temperature preferably lying between 1 100°C and 1400°C. Optionally, between step (a) and step (b) the pyrolyzed material can be further activated by any appropriate means known to persons skilled in the art, such as steam activation or C02 activation, either non catalytic or catalytic, in order to increase the mesopore volume per gram of carbon.

In one advantageous variant, one uses a carbon preform comprising silicon in an approximately stoichiometric proportion, and the method according to the invention comprises the steps of

(a) Pyrolysis of a preform of a mesoporous carbon precursor comprising at least one silicon source for obtaining a mesoporous carbon containing silicon, whereas the

C/Si mol ratio is about one, but preferably larger than 1 .05;

(b) Transformation of said mesoporous preform containing carbon and silicon into mesoporous β-SiC by reaction in a non oxidizing atmosphere at a temperature preferably lying between 1 100°C and 1400°C. In this embodiment, for pore diameters in the 6 nm to 100nm range, the pore volume of the final SiC is typically about 105% to 135% of the pore volume of the preform containing carbon and silicon, and about 30% to 40% of the pore volume of the carbon part of the mesoporous carbon containing silicon. This embodiment is exemplified in examples 5 and 7.

In another advantageous variant that constitutes a modification of the previous variant, the method according to the invention comprises the steps of

(a) Pyrolysis of a preform of a mesoporous carbon precursor comprising at least one silicon source for obtaining a mesoporous carbon containing silicon, whereas the C/Si mol ratio is larger than 1 , typically larger than 1 .35;

(b) Activation of this preform of mesoporous carbon containing silicon under steam or C02 to selectively burn off part of the carbon content, so as to further increase its pore volume per gram of carbon, and whereas the final C/Si mol ratio is about one, preferably larger than 1 .05;

(c) Transformation of said mesoporous preform containing silicon into mesoporous β-

SiC by reaction in a non oxidizing atmosphere at a temperature preferably lying between 1 100°C and 1400°C.

In this embodiment, for pore diameters in the 6 nm to 100nm range, the pore volume of the final SiC is typically about 105% to 135% of the pore volume of the activated preform containing carbon and silicon, and about 30% to 40% of the pore volume of the carbon part of the activated mesoporous carbon containing silicon. In another advantageous embodiment, one uses a carbon preform that is converted into SiC by using an external source of silicon, and the method according to the invention comprises the steps of

(a) Pyrolysis of a preform of a pure mesoporous carbon precursor for obtaining a pure mesoporous carbon. Optionally, this pure carbon can be activated under steam or

C02 to selectively burn off part of the carbon and further increase its mesopore volume per gram of carbon.

(b) Transformation of said pure mesoporous carbon preform into mesoporous β-SiC by reaction with an external source of silicon, in a non oxidizing atmosphere at a temperature preferably lying between 1 100°C and 1400°C.

In this embodiment, for pore diameters in the 6 nm to 100nm range, the pore volume of the SiC derived from the pure mesoporous carbon preform is expected to be about 65% to 80% of the pore volume of the pure mesoporous carbon preform. This embodiment is exemplified in examples 4 and 8.

In another advantageous embodiment, the method according to the invention comprises the steps of

(a) Pyrolysis of a preform of a mesoporous carbon precursor comprising at least one silicon source for obtaining a mesoporous carbon containing silicon, which can optionally be activated under steam or C02, whereas the final Si/C mol ratio is less than 1 , and possibly comprised between 0.05 and 0.95 ;

(b) Transformation of said mesoporous preform containing silicon into mesoporous β- SiC by reaction with an external source of silicon, in a non oxidizing atmosphere at a temperature preferably lying between 1 100°C and 1400°C. Optionally, between the pyrolysis step (a) and the transformation step (b) the pyrolyzed material is activated in order to increase the mesopore volume, preferably by steam activation or C02 activation, either non catalytic or catalytic.

In this embodiment, for pore diameters in the 6 nm to 100nm range, the pore volume of the SiC derived from the mesoporous carbon preform containing a sub-stoichiometric amount of silicon is typically 30% to 80% of the pore volume of the carbon part of the mesoporous carbon containing silicon, depending on the Si fraction contained in the mesoporous preform of carbon containing silicon. In another embodiment, said mesoporous carbon preform is produced from a mesoporous carbon precursor that may be a mesoporous phenolic resin, preferably a phenolic plastic, and even more preferentially selected from the group formed by mesoporous resoles, mesoporous novolaks and mixtures of the two.

Said silicon source may be selected from the group formed by metallic silicon, silica, silicon compounds and mixtures thereof. In particular, silicon powder can be used.

In one embodiment, said silicon source is intimately mixed with said mesoporous carbon precursor. Advantageously, a preform is prepared from the mixture between said mesoporous carbon precursor and said silicon source. Said silicon source may be incorporated in said mesoporous carbon precursor before the shaping leading to said preform, or contributed from the outside, for example in the form of species of gaseous SiO formed in the carburising reactor.

Said preform may be obtained by a shaping method selected from the group formed by extrusion, pressing of dough, atomisation, granulation, grinding, powder pressing, pouring in a mould, emulsion, coating, or by a combination of these methods.

Said mesoporous carbon precursor may present itself before the shaping leading to said preform in a crosslinked, partially crosslinked and/or non-crosslinked form. Said at least partially crosslinked preform advantageously has a mesopore volume of at least 0.25 cm3 per gram of crosslinked resin, preferably at least 0.35 cm3 per gram of crosslinked resin, and even more preferentially at least 0.40 cm3 per gram of crosslinked resin, and still more preferably at least 0.45 cm3 per gram of crosslinked resin, measured after drying and/or crosslinking at 150°C. This at least partially crosslinked preform, which is mesoporous, is next pyrolysed, as described above, to form the mesoporous carbon preform, which is then transformed into a shaped piece made from mesoporous β-SiC. When the at least partially crosslinked preform is transformed into a shaped piece made from β-SiC by passing through a carbon preform, the peak of the distribution of the mesoporous diameter moves towards larger diameters. It is thus possible to adjust the distribution of the mesopore diameter of the shaped piece made from β-SiC by using a resin or a carbon preform of suitable mesoporosity.

The second subject matter of the invention is a shaped material or piece made of β-SiC able to be obtained by the method according the first subject matter of the invention and/or variants thereof, said piece being characterised in that it has mesopores with a diameter of between 6 nm and 100 nm corresponding to a mesopore volume of at least 0.35 cm3/g, preferably at least 0.40 cm3/g and even more preferentially at least 0.45 cm3/g (determined by mercury intrusion porosimetry). In an advantageous embodiment, this shaped piece is characterised in that it has a BET specific surface area of at least 30 m2/g and preferably between 30 and 100 m2/g. Even more preferentially, the "mesoporous" surface area calculated by the BET surface area less the microporous surface area is at least 30 m2/g, preferably at least 40 m2/g, even more preferentially at least 50 m2/g, and optimally at least 60 m2/g.

A third subject matter of the invention is the use of a shaped material or piece able to be obtained by the method according to the invention, and more particularly the use of a shaped piece as described above by its mesoporosity, as a catalyst carrier for reactions involving at least one liquid phase. Having regard to the great chemical resistance of SiC and the stability of its mesoporous structure, a shaped material or piece according to the invention lends itself just as well to use as a catalyst carrier in an aggressive liquid medium, for example for reactions aimed at biomass conversion. The shaped material or pieces according to the latter subject matter of the invention are particularly suitable as a catalyst carrier for the Fischer-Tropsch reaction; this reaction poses very special problems with respect to the choice of the catalyst carriers, since it transforms gaseous molecules among the most simple (H2 and CO, in the form of gases that are pure or not) into a mixture of hydrocarbon molecules with very different masses, said molecules being able to be in the form of gases or liquids (which may be very viscous (waxes)) under the conditions of their catalytic synthesis. Said catalyst carrier for the Fischer-Tropsch reaction may comprise an active cobalt phase to the extent of approximately 5% to 30% by mass. Another subject matter of the invention is a method of preparing a catalyst precursor comprising the steps of preparing a catalyst support in the form of beta-SiC shaped pieces according to the invention, and introducing a catalyst precursor compound of an active catalyst component onto and/or into said catalyst support.

Still another subject matter of the invention is a catalyst precursor comprising a catalyst support in the form of a beta-SiC shaped piece according to the invention, and a catalyst precursor compound of an active catalyst component supported by the catalyst support. Still another subject matter of the invention is a method of preparing a catalyst including the steps of preparing a catalyst precursor using the method according to the invention, and reducing the catalyst precursor, thereby activating the catalyst precursor and obtaining the catalyst.

Still another subject matter of the invention is a catalyst comprising a catalyst support in the form of a beta-SiC shaped pieces according to the invention, and an active catalyst component supported by the catalyst support. A last subject matter of the invention is a hydrocarbon synthesis process comprising contacting hydrogen with carbon monoxide at a temperature above 100°C (preferably from 180 to 250°C, more preferably 220 to 230°C) and a pressure of at least 10 bar (preferably from 10 to 70 bar) with a catalyst according to the invention in order to produce hydrocarbons and optionally oxygenates of hydrocarbons. This process may comprise a hydroprocessing step for converting the hydrocarbons and optionally oxygenates thereof to liquid fuels and/or chemicals.

Figures

Figures 1 to 13 illustrate various aspects of the invention and of the prior art. Figure 1 shows the X-ray diffractogram of a β-SiC sample according to Example 4 (sample produced by the process according to the invention).

Figures 2 and 3 show the distribution of the pore volume for various diameters of pores obtained by mercury intrusion of the samples according to the prior art described in Example 1 (for figure 2) and Example 2 (for figure 3):

- curve A (dotted line): resin containing silicon inclusions, after drying at 150°C,

- curve B (broken line): carbon preform containing silicon inclusions, obtained by pyrolysis of the resin,

- curve C (black line): β-SiC shaped piece obtained from the carbon preform containing Si inclusions.

Figure 4 shows the distribution of the pore volume for various pore diameters obtained by mercury intrusion of the samples described in Example 4 (samples produced by the method according to the invention):

- curve A (dotted line) carbon balls,

- curve B (black line): β-SiC balls obtained from these carbon balls.

Figure 5 shows the X-ray diffractogram of a β-SiC sample according to Example 5 (sample produced by the process according to the invention).

Figure 6 shows the distribution of the pore volume for various pore diameters obtained by mercury intrusion of the samples according to the invention described in Example 5:

- curve A (dotted line): resin preform containing silicon inclusions, after drying at 150°C, - curve B (broken line): carbon preform containing silicon inclusions, obtained by pyrolysis of resin,

- curve C (black line): β-SiC shaped piece obtained from the carbon preform containing silicon inclusions.

Figure 7 shows micrographs recorded by scanning electron microscopy of the β-SiC products obtained according to prior art Example 2 (figure 7a), according to inventive Example 5 (figure 7b) and according to prior art Example 1 (figure 7c). The bar at bottom right of each micrograph indicates 100 nm.

Figure 8 shows the distribution of the pore volume for various pore diameters (obtained by the BJH (Barret-Joyner-Halenda) technique using the nitrogen adsorption (physisorption) isotherm) of the samples according to the prior art described in Example 6. Curve A shows the pore distribution of a microporous β-SiC carrier, curve B shows the pore distribution of the same carrier after deposition of 10% by weight finely divided cobalt.

Figure 9 shows the X-ray diffractogram of a β-SiC sample according to example 7 (sample produced by the process according to the invention). Figure 10 shows the distribution of the porous volume for different pore diameters obtained by mercury intrusion for the sample described in Example 7 (sample produced by the process according to the invention):

- Curve A (dotted line): carbon obtained by pyrolysis, with silicon inclusions;

- Curve B (black line): β-SiC obtained from this carbon with silicon inclusions, after elimination (burning) of residual carbon by oxidation.

Figure 1 1 shows the distribution of the porous volume for different pore diameters obtained by mercury intrusion for the samples of commercially available carbon balls used in Example 4 (Curve B, black line) and in Example 8 (Curve A, dotted line).

Figure 12 refers to Example 8 (according to the invention) and shows the distribution of the porous volume for different pore diameters obtained by mercury intrusion for the samples of commercially available carbon balls used (Curve A, black line), and of the SiC balls obtained from these carbon balls (Curve B, grey line). The dotted grey curve (Curve C) refers to the same SiC balls after oxidation for three hours at 700°C in air.

Figure 13 shows images obtained by scanning electron microscopy of the carbon balls used in Example 8 (figure 13a) and of the SiC balls obtained in Example 8 (figure 13b). The white bar in the lower right edge of the photograph indicates the length of 100 μηι.

Description

1 ) Definitions and characterisation methods

The definition of mesoporosity according to UIPAC relates to pores with a diameter of between 2 nm and 50 nm (see the article published by lUPAC in Pure & Applied Chemistry, cited above, see also the article "Texture des materiaux pulverulents ou poreux" by F Rouquerol et al, which appeared in the collection Techniques de I'lngenieur, chapter P 1050). In the context of the present invention, mesoporosity is defined on the basis of pores with a diameter between 6 nm and 100 nm. The inventors have found that, for heterogeneous catalysis, and in particular for catalysis involving heavy molecules, this range of pores appears to be optimum for limiting diffusion in the pores while generating sufficient specific surface area for dispersing the active phase. The preferred characterisation technique for measuring the distribution of the pore size (and in particular of the pores that contribute to this mesoporosity) and for determining the mesopore volume is the measurement of the penetration of mercury (also referred to as "mercury intrusion porosimetry") assuming a fixed Hg contact angle of 130°. The Micromeritics™ AUTOPORE™ apparatus can be used. The resolution of this apparatus may be as much as 6 nm. Pore sizes greater than 100 nm will generate little specific surface area, and for example a solid having pores of 100 nm and a pore volume of 0.5 cm3/g will have a maximum specific surface area of 20 m2/g (taking pores with a cylindrical shape as the model).

The specific surface area is measured by the adsorption of nitrogen using the Brunauer, Emmet and Teller model (referred to as BET specific surface), described initially in J American Chemical Society, vol. 60, p. 309-319 (1939) and well known to persons skilled in the art (see for example the aforementioned article by F Rouquerol et al, or the book

"Adsorption" by K Hauffe and S R Morrison, Berlin 1974, p. 19-23). This measurement was the subject of the French standard NF X 1 1 -621 ; it can be made on a Micromeritics™ Tristar™ 3000 apparatus. The microporous surface area is determined by a so-called t-plot trace, deducing the external surface area. The t-plot method (or "t method") according to de Boer makes it possible to determine the micropore volume of a solid as well as its external area. The external area is the extent of the surface area of a non-porous, macroporous or mesoporous solid (excluding the contribution of the micropores). In the case of an absorbent containing micropores, the BET area and the external area, normally denoted a(t), can be compared, on which a multimolecular layer can be formed with the relative equilibrium pressure; the thickness t of this layer increases with the equilibrium pressure. The difference between BET area and the external area is the surface area contributed by the micropores. A detailed description of the technique is given in the abovementioned article by F Rouguerol et al.

2) Detailed description

2.1 Preparation of shaped β-SiC material

The inventors have found that the method for synthetising β-SiC shaped products by the shape memory synthesis methods according to the prior art leads to β-SiC products that are not particularly well suited for certain liquid-phase catalytic applications or ones involving heavy molecules. They have also found that a critical aspect for these applications is the distribution and the mesopore volume: a β-SiC carrier having a high mesopore volume is more suitable than a β-SiC carrier having high microporosity, the latter being particularly desirable in gaseous reactions involving simple molecules (for example the depollution of exhaust gases, see for example WO 2005/038204).

More particularly, the methods described in the aforementioned document US 6,184,178 and publication by P Nguyen and C Pham, which involve the following steps:

(i) combining silicon powder with a carbonisable thermoplastic or thermosetting resin, optionally addition additives such as other sources of carbon (for example: carbon black, acetylene black, activated carbon), porogens, plasticisers, lubricants;

(ii) shaping this mixture:

(iii) subjecting the shaped mixture to a thermal cycle which comprises a low- temperature step at approximately 150°C in order to dry and harden the resin if this resin is thermosetting;

(iv) subjecting the shaped mixture (optionally hardened at step (iii)) to a heat treatment at a temperature of between approximately 1200°C and approximately 1400°C, in a non-oxydising atmosphere (argon for example);

lead to products having a pore volume stemming from mesoporosity of between 6 nm and 100 nm of less than 0.3 cm3/g. This is illustrated in examples 1 and 2.

Without wishing to be confined in this theory, the inventors think that, in this method according to the prior art, the mesoporous lattice is formed by:

(a) interstitial gaps between the primary particles of SiC, (b) cracks that form around silicon particles in the carbonised polymer resin,

(c) interstitial gaps in the additives (carbon black, acetylene black) converted into β-SiC,

(d) other gaps and fissures. As indicated above, this known method consists of the conversion of a carbon precursor preform that comprises silicon powders as a source of silicon, into a porous β-SiC shaped piece that is suitable as a catalyst carrier. The present inventors discovered that, when this preform comprises mesopores, these mesopores are preserved in the β-SiC shaped piece. The choice of this precursor is critical. By way of example, activated carbon is not suitable. The inventors discovered that it is possible to use as a mesoporous preform either a carbon precursor preform or a preform already carbonised.

It is known that porous carbon (in particular activated carbon) is mainly microporous. It may be obtained by the calcination of a natural precursor (wood, coal, etc.) in an inert atmosphere, which leads to charcoal and tar, and then by the activation of the carbon by steam or C02. The activated carbon that results therefrom has a very high specific surface area greater than 500 m2/g, and is microporous (pores with a diameter of less 2 nm). Tests on enlarging the pores of the activated carbon by catalytic activation or activation by water vapour or C02 have not made it possible to control the diameter of the pores.

The present inventors discovered that, when mesoporous resins are used for synthesising β-SiC, the mesoporosity of the mesoporous resin was preserved at least partially in the β- SiC piece. In the method according to the present invention, phenolic resins are advantageously used, which are preferably phenolic plastics that result from the reaction between phenol (possibly substituted) and formaldehyde. These resins are known as such, and have already been used for manufacturing carbon preforms by pyrolysis. They may in particular be of the resole type or of the novolac type.

Novolacs are formed in an acid medium with formaldehyde/phenol molar ratios of less than 1 , for example 0.75. These are in general solids with a melting point up to 120°C, soluble and fusible; they can be crosslinked by adding a crosslinking agent, typically a hexamethylene tetramine (HMT), which dissolves in the novolac in the molten stage and decomposes by hydrolysis. Resoles are formed in a basic medium with formaldehyde/phenol molar ratios greater than 1 and up to 3, for example 1 .5. The crosslinking takes place spontaneously during heating or sometimes by the addition of acid; it leads to an insoluble and non-fusible polymer. It is known that phenolic resins can be converted into a porous carbonaceous structure by carbonisation in an inert atmosphere using a temperature of approximately 600°C. After carbonisation, the solid loses approximately 50% of its mass, and its volume reduces by approximately 50%. The product obtained has a continuous vitreous structure with a specific surface area of around 500 m2/g by virtue of the micropores generated by gaps between particles. The median pore size is in general less than 1 nm. The carbon that results therefrom is in general not mesoporous and the pore volume corresponding to the pores with a diameter of between 6 and 100 nm is extremely small. Activation at high temperature (above 750°C) under water vapour and/or C02 will lead to an increase in micropore volume and consequently the specific surface area; this is accompanied by a loss of mass and leads to a reduction in mechanical strength. These resins are therefore not suitable as they stand in the context of the present invention.

According to the invention, mesoporous carbon can be manufactured by pyrolysis of a mesoporous phenolic resin. A mesoporous phenolic resin can be manufactured by various methods, for example by the addition of a porogen to a phenolic resin, followed by crosslinking thereof, removal of the porogen and carbonisation of the phenolic resin in order to obtain the mesoporous carbon. Another method that may suit is described in the patent US 8,227,518 B1 (British American Tobacco Ltd).

A description will now be given in detail of the method according to the invention. The present invention concerns a method for manufacturing a β-SiC mesoporous shaped piece that can be used as a catalyst carrier. This method comprises a step in which a preform is obtained comprising a mixture of a mesoporous phenolic resin with a source of silicon (preferably silicon powder), and a step in which said preform is subjected to a heat treatment in a non-oxidising atmosphere in order to transform said mesoporous phenolic resin into a β-SiC mesoporous piece. Typically, the resin preform is dried and crosslinked and then pyrolysed in order to form a mesoporous carbon preform. Optionally, the carbon preform can be activated under a stream of either steam or C02 in order to further increase its mesopores volume per gram of carbon. The transformation into β-SiC proceeds by reaction between the carbon and silicon, probably passing through the intermediate reactive species SiO. The silicon can be contained in the carbon preform, for example in the form of an elementary silicon powder (Dubots method, see EP 0 440 569 B1 or EP 0 952 889 B1 ), as described above, and/or in the form of silica powder, and/or it may be contributed from outside, for example in the form of SiO vapour (Ledoux method, see EP 0 313 480 B1 ). According to the invention, said β-SiC mesoporous piece has a mesopore volume relating to the pores with a diameter of between 6 nm and 100 nm that is greater than 0.30 cm3/g, preferably greater than 0.35 cm3/g, but for reactions involving heavy molecules such as the Fischer-Tropsch reaction a mesopore volume greater than 0.40 cm3/g or even greater than 0.45 cm3/g is preferred.

The inventors found that the mesoporosity of the phenolic resin was preserved at least partially in the β-SiC piece. The specific surface area of the β-SiC mesoporous piece according to the invention is typically comprised between 30 m2/g and 100 m2/g, the major part of this surface area being generated by mesopores with a size of between 6 nm and 100 nm, and in particular by mesopores with a size of between 10 nm and 50 nm. This mesoporosity is obtained from a carbon preform having mesopores with a diameter of between 6 nm and 1 00 nm with a pore volume greater than 0.30 cm3 per gram of carbon (and preferably greater than 0.35 cm3 per gram of carbon and even more preferentially greater than 0.40 cm3 per gram of carbon). Such a mesoporous carbon preform may be obtained from a carbonisable mesoporous resin having (after drying and cross-linking) mesopores with a diameter of between 6 nm and 100 nm with a pore volume greater than 0.30 cm3 per gram of resin (and preferably greater than 0.35 cm3 per gram of resin and even more preferentially greater than 0.40 cm3 per gram of resin). Said preform may contain a silicon precursor, for example elementary silicon powder or silica. In general terms, if the silicon precursor is integrated in the resin (for example in the form of silicon powder or silica powder), it is advantageous to adjust the composition of the resin so that the carbon preform (after pyrolysis or pyrolysis followed by activation) has an Si/C molar ratio of approximately 1 ; in making this adjustment account is taken in particular of the carbon yield of the resin under the pyrolysis conditions. A person skilled in the art will usefully refer to the execution examples given below.

In general terms, according to the present invention, mesoporous β-SiC pieces can be obtained by the following methods:

(1 ) A carbonisable resin (typically a phenolic resin) is shaped in order to obtain a mesoporous carbonisable resin preform, and said mesoporous preform is pyrolysed in an inert atmosphere in order to obtain a mesoporous carbon preform. Next said mesoporous carbon preform is put in contact with a source of gaseous SiO, such as Si02, Si or a mixture of the two, and the mesoporous preform is transformed into a β-SiC mesoporous shaped piece at high temperature by the reaction of the gaseous SiO with the mesoporous carbon shaped piece. This method can be performed in a single step with a continuous temperature rise or in steps, to dry the resin after the shaping, to pyrolyse the resin, to form the carbon preform and then to form the carbide with the gaseous SiO source.

(2) A preform of a non-crosslinked or partially crosslinked phenolic resin is produced, which contains silicon powder, and this preform is transformed into a mesoporous β-SiC shaped piece at high temperature under inert atmosphere; the phenolic plastic resin may be partially crosslinked.

(3) A preform of a partially or completely crosslinked mesoporous phenolic resin or of a mesoporous carbon is produced, containing silicon powders and a specific binder, said binder being able preferably to be a precursor of β-SiC, such as a mixture of a phenolic resin with silicon powders, and this preform is transformed at high temperature in an inert atmosphere into a β-SiC mesoporous shaped piece. In conventional activated carbon, the mesoporous structure with a diameter < 2 nm as defined by l U PAC reflects the nature of the precursor and is generally considered to have a slot shape derived from the space between bonded sheets of condensed aromatic rings. The nanostructure of the carbon materials derived from phenolic resin is very different: it derives from the crosslinking method. This method leads to very small highly crosslinked resin domains that form during the pyrolysis of the dense microdomains, very close together, of vitreous carbon. This structure leads to a mean size of pores generated by the gaps between particles; this size is around 0.8 nm. A more detailed presentation of the carbonaceous materials derived from phenolic resins was given by S R Tennison in Applied Catalysis A: General 173 (1998) 289-31 1 .

Mesopores with a size greater than 2 nm (according to the definition of the l UPAC) or with a size greater than 6 nm (as defined in the context of the present invention) may be introduced into the carbonaceous materials derived from the phenolic resins by a solvent- based method described in the aforementioned patent US 8,227,518. In this method, the precursor resin of the novolac type and the crosslinking agent are dissolved in the porogenic solvent in order to create a mass (mesoporous resin precursor mixture) which typically has the consistency of a gel and the viscosity of which depends more generally on the proportions of resin and solvent. In order to form resin balls, this solution is dispersed in hot oil: the contact with the hot oil initiates the crosslinking of the resin on the surface of the ball and fixes its geometry. In order to form blocks of resin, the viscosity is adjusted and the mesoporous resin precursor mass is shaped. The solvent trapped in the mesoporous resin precursor mass generates the mesopores; this mesoporous structure must be fixed by at least partial crosslinking before the complete removal of the porogenic solvent. After removal of the porogenic solvent and carbonisation (under protective gas, such as nitrogen or argon), the at least partially crosslinked phenolic resin mesoporous preforms (for example the balls) are transformed by pyrolysis into mesoporous carbon preforms (for example in balls). Such a mesoporous material is available commercially (from the company MAST Carbon UK), in particular in the form of balls. This form is well suited to the present invention, but is not the only one possible. It is also possible to prepare blocks of mesoporous resin of any form, to reduce these blocks (typically by crushing and/or grinding) into powder and to integrate this powder in a carbonisable crosslinkable resin (for example phenolic) that is shaped in order to obtain a preform (a shaped piece) of mesoporous resin, for example according to variants (1 ) and (2) indicated above.

The mesoporous carbon preforms, and in particular the balls, can be put in contact with a fine (elementary) silicon and/or silica powder that acts as a gaseous SiO precursor diffusing inside the ball during the carburation reaction. In a preferred embodiment, the gaseous SiO precursor is elementary silicon. The silicon particles are advantageously of average size of less than 5 μηη (preferably less than 3 μηη) and the mixture can be developed in a high-shearing solid mixer or by means of an alcoholic suspension of the carbon balls with the silicon particles. When the suspension is dried, the powders come into close contact with the balls.

The solid mixture is then heated at a temperature below 1400°C (but sufficient to form the SiC) under argon in order to transform the mesoporous carbon preforms (for example the balls) into mesoporous β-SiC shaped pieces (for example balls).

In a similar manner, the gaseous SiO precursor (for example the elementary silicon powder or the silica powder) can be introduced directly into the mesoporous resin precursor mixture, the resin is at least partially crosslinked in order to obtain an at least partially crosslinked mesoporous resin preform, and then said at least partially crosslinked resin preform is pyrolysed in order to obtain the mesoporous carbon preform. Then the carburation is carried out on the carbon preform under the conditions indicated above; during this step, the silicon present in the resin reacts with the carbon (probably by means of the SiO gaseous species, but this hypothesis has no limiting effect on the scope of the invention). In some cases it may be useful to burn any excess of carbon.

In this way mesoporous β-SiC shaped pieces are obtained that have (i) the form of the mesoporous carbon preform, and (ii) a mesoporosity similar to that of the mesoporous carbon preform. As shown in the examples, it is possible to characterise the mesoporosity (and in particular the mesopore volume) for the at least partially crosslinked resin shaped piece, for the pyrolysed carbon shaped piece and for the β-SiC shaped piece.

In the method according to the invention, the at least partially crosslinked resin mesoporous preform, the carbon mesoporous preform and the β-SiC mesoporous shaped piece may have any shape; it may for example be in the form of balls (of different sizes), pellets, cylindrical or rectangular pieces, rings, plates, alveolar foams or moulded pieces.

Example 4 below describes in detail the mesoporous β-SiC material that results from the transformation of mesoporous carbon ball preforms into β-SiC mesoporous balls according to the invention; the mean diameter of the pores of the mesoporous carbon is maintained and even slightly increased when the material is transformed into silicon carbide. Another embodiment of the method according to the invention for manufacturing mesoporous β-SiC shaped pieces, in the form of microballs, consists of manufacturing a mesoporous phenolic resin precursor mixture comprising particles of silicon, and shaping it before crosslinking of the resin, by atomisation or a method involving an emulsion. In a variant of this embodiment, the shaping is effected by pouring or moulding.

After the shaping, the mesoporous phenolic plastics comprising the silicon particles can be transformed into mesoporous β-SiC balls, spherical in shape and having a smooth surface. In another embodiment of the method according to the invention, a mesoporous phenolic resin is manufactured contained silicon particles and the material is partially crosslinked, and then the material is ground in order to obtain the required particle size.

The partially crosslinked mesoporous phenolic resin containing silicon powder can be shaped by any method known to persons skilled in the art, such as: extrusion, granulation, pressing of tablets, atomisation.

By way of example, the powders can be shaped by extrusion with the addition of water and a binder for a green piece, such as PVA or cellulose ether. After drying, the preform is subjected to a heat treatment leading to the sintering of the crosslinked phenolic plastic particles comprising particles of silicon between them. The phenolic plastic preform comprising silicon particles can then be transformed into a β-SiC shaped piece at a temperature between 1200°C and 1400°C under a non-oxidising atmosphere. Yet another method for producing mesoporous β-SiC shaped pieces consists of the shaping of phenolic resin comprising silicon particles, said phenolic resin being fully crosslinked and ground, said shaping taking place by means of a binder comprising a mixture of phenolic resin and silicon, wherein said mixture can be composed of partially crosslinked phenolic resin containing silicon.

2.2 The catalyst precursor a) Introduction

The product obtainable by the method according to the invention, namely the mesoporous β-SiC shaped material or shaped pieces, can be used as a catalyst carrier, in particular in transported and/or fluidised bed reactors, or in suspended bubble column reactors, since it is possible to prepare β-SiC balls the shape of which may be perfectly spherical with a smooth surface and a high resistance to attrition. A preferred use of these balls is that as a catalyst carrier for the Fischer-Tropsch reaction used in a suspended bubble column. The product obtainable by the method according to the invention may also be used in other geometric forms, for example in the form of extruded pieces, and in particular in fixed-bed reactors (for example for catalysing the Fischer-Tropsch reaction).

In order to use the catalyst carrier according to the invention in a catalytic process, a catalyst precursor usually needs to be formed first, by applying a precursor compound of an active catalyst component (said active catalyst component being also called active phase) to said catalyst carrier, often followed by calcination (usually thermal decomposition of a metal salt (the precursor compound) into a metal oxide). This is usually followed by an activation stage (reduction by a reducing agent such as hydrogen) that may be carried in situ, i.e. inside the catalytic reactor. Said precursor compound usually is an oxygen-bearing metal salt, such as a carbonate or a nitrate. b) The catalyst precursor

The catalyst precursor may comprise a catalyst support in the form of beta-SiC shaped material or shaped pieces according to the invention and at least one compound of an active catalyst component carried on the catalyst support. The active catalyst component may be any suitable component, but preferably it is a component catalytically active in a process for synthesising hydrocarbons and/or oxygenates of hydrocarbons from at least hydrogen and carbon monoxide. Preferably the process is a FT synthesis process. The FT process may be performed in a fixed bed reactor, slurry bed reactor or a fixed fluidized bed reactor. Preferably the FT process is a three phase slurry bed FT synthesis process. The active catalyst component may be a known component active for a FT synthesis process, and may be selected from the group consisting of cobalt (Co), iron (Fe), nickel (Ni) and ruthenium (Ru). Cobalt (Co) is preferred. The compound of the active catalyst component may be an oxide compound, including an oxy hydroxy compound. In the case of cobalt as an active catalyst component the compound of cobalt may be a compound selected from the group consisting of CoO, CoO(OH), C03O4, C02O3 or a mixture of one or more thereof. Preferably the active catalyst component of cobalt is selected from the group consisting of CoO, CoO(OH) and a mixture of CoO and CoO(OH).

The catalyst precursor may contain cobalt (Co) as an active component at a loading of from 5 to 70 g Co/100 g catalyst support preferably from 20 to 40 g Co/100 g catalyst support, and more preferably from 25 to 35 g Co/100 g catalyst support. c) Catalyst precursor preparation

The catalyst precursor may be prepared by introducing a catalyst precursor compound of the active catalyst component onto and/or into a catalyst support in the form of beta-SiC shaped material or shaped pieces according to the invention, as described above.

The active catalyst component is a component as described hereinabove, and preferably it is cobalt.

The catalyst precursor compound may be any suitable compound of the active catalyst component. Preferably it is an inorganic compound, preferably an inorganic salt of the active catalyst component. The catalyst precursor compound may be cobalt nitrate, and particularly it may be Co(N03)2-6H20.

The catalyst precursor compound may be introduced onto and/or into the catalyst support by any suitable manner, but preferably it is by means of impregnation. Preferably the catalyst support is impregnated by the catalyst precursor compound by forming a mixture of the catalyst precursor compound; a liquid carrier for the catalyst precursor compound; and the catalyst support. The liquid carrier may comprise a solvent for the catalyst precursor compound and preferably the catalyst precursor compound is dissolved in the liquid carrier. The liquid carrier may be water. The impregnation may be effected by any suitable impregnation method, including incipient wetness impregnation or slurry phase impregnation

The impregnation may be carried out at sub-atmospheric pressure, preferably below 85 kPa(a), preferably at 20kPa(a) and lower. Preferably the impregnation is also carried out at a temperature above 25°C (replaces elevated temp.). Preferably the temperature is above 40°C, preferably above 60°C, but preferably not above 95°C.

The impregnation may be followed by partial drying of the impregnated support, preferably at a temperature above 25°C. The partially dried catalyst support with the catalyst precursor compound thereon and/or therein may be calcined. The calcination may be effected in order to decompose the catalyst compound or causing it to react with oxygen. For example, cobalt nitrate may be converted into be a compound selected from CoO, CoO(OH), Co304, Co203 or a mixture of one or more thereof.

The calcination may be carried out in an inert atmosphere, but preferably it is carried out in the presence of oxygen, preferably in air.

Preferably the calcination is carried out at a temperature above 95°C, preferably above 120°C, preferably above 200°C, and more preferably above 400°C, preferably at least 450°C, preferably at least 500°C and even above 550°C, but preferably not above 650°C. This is especially the case where cobalt is the active catalyst component.

The impregnation, the partial drying and calcination may be repeated to achieve higher loadings of the catalyst precursor compound on the catalyst support. One unexpected advantage of the catalyst carriers according to the invention is that, because of the larger volume of pores (i.e. because of the fact that the mesoporosity is increased), manufacture of catalyst precursors by impregnation of the supports with a precursor of the active phase in the liquid phase is facilitated. By way of example and as explained above, it is known that, for preparing catalysts for the Fischer-Tropsch reaction, a high metal charge (typically cobalt) is necessary. As explained above, this metal is added by impregnation of the support with a solution of a salt of the required metal (cobalt) in a suitable solvent, followed by drying and calcination of the carrier, in order to transform the salt into metal oxide; this oxide is subsequently reduced into finely divided metal that forms the active phase. However, with the carriers according to the prior art, this impregnation must be repeated several times in order to achieve the necessary metal salt charge; this well-known problem in particular with catalysts for the Fischer-Tropsch reaction, which require a particularly high metal charge, is described for example in the patent US 6,130,184 (Shell). The applicant has found that, with the mesoporous carrier according to the invention, at least one impregnation operation, for achieving an equal metal salt charge, is saved on. This is probably due to the fact that, in the carriers according to the invention, the penetration of a larger metal salt solution volume makes it possible, for an identical concentration, to deposit a higher quantity of salt in the whole of the mesoporosity. d) Active catalyst

The active catalyst comprises the catalyst precursor which has been subjected to an activation step to reduce the compound of the active catalyst component to a catalytically active form.

The active catalyst may comprise a catalyst support in the form of beta-SiC shaped pieces as described above; and at least one active catalyst component in a catalytically active form carried on the catalyst support. The catalyst component may be any suitable component, but preferably it is a component catalytically active in a process for synthesising hydrocarbons or oxygenates of hydrocarbons from at least hydrogen and carbon monoxide. Preferably the process is a FT synthesis process, preferably a three phase FT synthesis process, preferably a slurry bed FT synthesis process.

The active catalyst component is a component as described above.

The active catalyst component is preferably in its metallic form to be in the catalytically active form. In a preferred embodiment of the invention the metallic active catalyst component is in the form of crystallites.

The active catalyst may contain cobalt (Co) as an active component at a loading of from 5 to 70 g Co/100 g catalyst support preferably from 20 to 40 g Co/100 g catalyst support, and more preferably from 25 to 35 g Co/100 g catalyst support. e) Active catalyst preparation

The active catalyst may be prepared by subjecting the catalyst precursor (preferably the calcined catalyst precursor) as described above to reduction conditions to activate the catalyst precursor.

The catalyst precursor is preferably treated with a reducing gas to activate the catalyst precursor. Preferably, the reducing gas is hydrogen or a hydrogen containing gas. The hydrogen containing gas may consist of hydrogen and one or more inert gases which are inert in respect of the active catalyst. The hydrogen containing gas preferably contains at least 90 volume % hydrogen.

The treatment with the reducing gas may be carried out at an elevated temperature, preferably of at least 200°C, more preferably at least 300°C, and most preferably at least 400°C, to activate the catalyst precursor. The temperature during treatment with the reducing gas is preferably at least 450°C, more preferably at least 500°C, most preferably about 550°C and even above. During reduction, cobalt metal may be formed. f ) Hydrocarbon synthesis

According to another aspect of the present invention there is provided a hydrocarbon synthesis process comprising contacting hydrogen with carbon monoxide at a temperature above 100°C (preferably from 180 to 250°C, preferably 220 to 230°C) and a pressure of at least 10 bar (preferably from 10 to 70 bar) with a catalyst as set out above in order to produce hydrocarbons and optionally oxygenates of hydrocarbons.

Preferably the hydrocarbon synthesis process is a Fischer-Tropsch process, preferably a three phase Fischer-Tropsch process, more preferably a slurry bed Fischer-Tropsch process for producing a wax product.

The hydrocarbon synthesis process may also include a hydroprocessing step for converting the hydrocarbons and optionally oxygenates thereof to liquid fuels and/or chemicals.

According to yet another aspect of the present invention there is provided products produced by the hydrocarbon synthesis process as described above.

The following examples illustrate certain aspects of the invention to enable a person skilled in the art to implement the invention, but do not limit the scope thereof.

Examples

Examples 1 to 3 and 6 illustrate methods according to the prior art, by way of comparison. Examples 4, 5, 7, and 8 illustrate methods according to the invention. Example 1 (comparative): Standard porous SiC material

This example duplicates example 1 of the patent US 6,184,178.

1500 g of silicon powder, 448 g of carbon black (BET surface area = 100 m2/g), 502 g of a solid phenolic resin, 50 g of hexamethylene tetramine (crosslinking agent), 900 g of water and 150 g of plasticiser were mixed. This mixture was shaped in an extrusion press in order to obtain cylindrically shaped extruded pieces with a diameter of 1 mm and a length of approximately 3 mm. These pieces were heated for 3 hours at 150°C in air in order to dry them and harden the phenolic resin. These dried pieces have a mesopore volume of 0.01 cm3/g and 0.06 cm3/g for pores with a diameter of between respectively 6 nm and 50 nm, and 6 nm and 100 nm.

These dried pieces were heated under argon at atmospheric pressure at a temperature of 800°C in order to pyrolyse the resin and transform it into carbon. The material obtained has a mesopore volume of 0.01 cm3/g and 0.07 cm3/g for the pores with a diameter between respectively 6 nm and 50 nm, and 6 nm and 100 nm. Its specific surface area is 122 m2/g, 1 15 m2/g of which is attributed to micropores. (The value of 0.07 cm3/g corresponds to 0.23 cm3 per gram of carbon for a C/Si molar ratio of 1 ; see table 1 ).

The same dried pieces were heated under argon at atmospheric pressure at a temperature of 1360°C in order to complete the pyrolysis of the resin and then produce the SiC. The material obtained has a mesopore volume of 0.17 cm3/g and 0.26 cm3/g for the pores with a diameter between respectively 6 nm and 50 nm and 6 nm and 100 nm. Its BET specific surface area was 30 m2/g, 0 m2/g of which was microporous surface area measured by the t-plot technique.

The pore distributions measured by mercury intrusion of these various samples are set out in figure 2. Figure 7c shows a micrograph (SEM) of the β-SiC product obtained.

Example 2 (comparative): Standard porous SiC material

This example illustrates another method according to prior art that uses, as a single source of carbon, a phenolic resin not having sufficient mesoporosity.

1500 g of silicon powder, 1 181 g of a solid phenolic resin, 78 g of hexamethylene tetramine (crosslinking agent), 500 g of water and 150 g of plasticiser were mixed. This mixture was shaped in an extrusion press in order to obtain cylindrically shaped extruded pieces with a diameter of 2 mm and a length of approximately 3 mm. These pieces were heated for 3 hours at 150°C in air in order to dry them and harden the phenolic resin. These dry pieces have a mesopore volume of 0.01 cm3/g and 0.02 cm3/g for pores with a diameter of between respectively 6 nm and 50 nm, and 6 nm and 100 nm. These dried pieces were heated under argon at atmospheric pressure at a temperature of 800°C in order to pyrolyse the resin and transform it into carbon. The material obtained has a mesopore volume of 0.04 cm3/g and 0.05 cm3/g for the pores with a diameter between respectively 6 nm and 50 nm, and 6 nm and 100 nm. Its specific surface area is 239 m2/g, 238 m2/g of which is attributed to micropores.

The same dried pieces were heated under argon at atmospheric pressure at a temperature of 1360°C in order to pyrolyse the resin and then produce the SiC. The material obtained has a mesopore volume of 0.18 cm3/g and 0.24 cm3/g for the pores with a diameter of between respectively 6 nm and 50 nm, and 6 nm and 100 nm. Its specific surface area measured by the BET technique was 21 m2/g, 0 m2/g of which was microporous surface area measured by the t-plot technique.

The pore distributions (measured by mercury intrusion) of these various samples are set out in figure 3. Figure 7a shows a micrograph (SEM) of the β-SiC product obtained.

In this example the great change is noted in the structure between the carbon piece, with a very high BET specific surface area but no mesoporosity, and the β-SiC piece which has a small microporous BET specific surface area but a relatively high mesoporosity; according to the findings of the present inventors, this value can be exceeded only by using a mesoporous resin.

Example 3 (comparative): Standard porous SiC material This example reproduces example 2, but using a greater quantity of phenolic resin in the initial mixture.

Thus 1500 g of silicon powder, 1235 g of a solid phenolic resin, 78 g of hexamethylene tetramine (crosslinking agent), 550 g of water and 150 g of plasticiser were mixed. This mixture was shaped in an extrusion press in order to obtain cylindrically shaped extruded pieces with a diameter of 2 mm and a length of approximately 3 mm. These pieces were heated for 3 hours at 150°C in air in order to dry them and harden the phenolic resin, and then they were heated under argon at atmospheric pressure at a temperature of 1360°C in order pyrolyse the resin, and then produce the SiC. The material obtained has a mesopore volume of 0.12 cm3/g and 0.17 cm3/g for the pores with a diameter of between respectively 6 nm and 50 nm and 6 nm and 100 nm. Its specific surface area measured by the BET technique was 57 m2/g including 32 m2/g of microporous surface area measured by the t-plot technique. The high specific surface area mainly consists of microporous surface area attributed to the presence of residual carbon in the material.

The residual carbon was then burnt by a heat treatment in air at 700°C. The material then had a mesopore volume of 0.15 cm3/g and 0.21 cm3/g for pores with a diameter of between respectively 6 nm and 50 nm and 6 nm and 100 nm. Its specific surface area measured by the BET technique was no more than 18 m2/g, including 2 m2/g of microporous surface area measured by the t-plot technique. This example demonstrates that the BET specific surface area is not a sufficient criterion for demonstrating the presence of a high mesopore volume. On the other hand, the difference between the BET surface area and the microporous surface area measured by the t-plot technique gives a better indication of the quantity of mesopores. Example 4 (according to the invention):

Mesoporous balls of β-SiC from mesoporous balls of carbon

Carbon balls with a diameter of between 90 μηη and 125 μηη having a BET specific surface area of 560 m2/g were procured (supplier: MAST Carbon, Basingstoke, UK; trade reference: TE3). These balls had been prepared from a mesoporous resin.

The mean size of the pores of these carbon balls was determined by nitrogen adsorption, and was 13 nm. Their mesopore volume was 0.24 cm3/g and 0.28 cm3/g for the pores with a diameter of between respectively 6 nm and 50 nm and 6 nm and 100 nm. Their BET surface area was 560 m2/g including 463 m2/g attributed to the micropores.

100 parts by mass of these carbon balls was mixed with 466 parts by mass of micronized silicon powder (d50 < 1 μηη) in ethanol in order to obtain a homogenous paste. After evaporation of the solvent the solid mixture was spread on a graphite sheet that was placed in an electric oven under controlled atmosphere. The oven was scavenged with argon and heated to 1360°C; this temperature was maintained for 1 hour. It was left to cool and then the resulting powder was sieved and washed with distilled water. The fraction sieved with a grain size of between 50 μηη and 150 μηη was washed with an aqueous solution of 20 parts by mass of NaOH at 70°C in order to eliminate any silica remains that might have been produced during the process.

The solid thus obtained had the crystallographic structure of β-SiC, as can be seen in Figure 1 ; it had a mesopore volume of 0.19 cm3/g and 0.20 cm3/g for the pores with a diameter of between respectively 6 nm and 50 nm and 6 nm and 100 nm. Its specific surface area measured by the BET technique was 38 m2/g of which 0 m2/g of microporous surface area measured by the t-plot technique.

After oxidation for three hours at 700°C in air the mesopore volume of the SiC balls remained virtually unchanged: 0.18 cm3/g and 0.19 cm3/g for the pores with a diameter of between respectively 6 nm and 50 nm and 6 nm and 100 nm.

The pore distribution curves (measured by mercury intrusion) in Figure 4 compare the initial carbonaceous material with the SiC material obtained after heat treatment in the presence of a source of silicon. This figure demonstrates that the initial mesostructure of the carbon is almost completely preserved after transformation into SiC, with a slight shift of the distribution curve towards the larger pore diameters. This example demonstrates that it was possible to convert a mesoporous carbonaceous preform into a mesoporous SiC shaped piece by the addition of an external source of silicon. In this case, there is a reduction by a factor of 1 .4 of the porous mesopore volume between the initial carbon and the final SiC. Surprisingly, this reduction is small compared with the theoretical loss of 3.3 expected according to the molar mass ratio between the starting carbon and the final SiC. It was found that the use of a carbon preform having a higher mesopore volume leads, after conversion into SiC according to this method described in the present example 4, to an SiC the mesopore volume of which is also increased and in particular greater than 0.35 cc/g if a carbonaceous preform is used the mesopore volume of which is greater than 0.50 cc/g (this will be demonstrated in Example 8).

Example 5 (according to the invention):

Mesoporous β-SiC shaped piece from mesoporous resin comprising a silicon powder

A mesoporous phenolic resin containing a dispersion of silicon powders was manufactured. Its composition was adjusted so as to produce, after pyrolysis, 100 parts by mass of mesoporous carbon, and it comprised 233 parts by mass of silicon powders with a particle size of d50 = 2.5 μηη. After shaping, the resin was heated for 3 hours at 150°C under air in order to dry and harden the resin. The dried product thus obtained had a mesopore volume of 0.40 cm3/g and 0.50 cm3/g for the pores with a diameter of between 6 nm and 50 nm and between 6 nm and 100 nm, respectively. These pieces were next heated under argon at atmospheric pressure at a temperature of 800°C in order to pyrolyse the resin and transform it into carbon. The material obtained had a mesopore volume of 0.32 cm3/g and 0.48 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm. Its specific surface area was 145 m2/g including 1 12 m2/g attributed to micropores.

These carbon pieces were heated at 1360°C for 1 hour in an electric oven under argon flow at atmospheric pressure, in order to produce the SiC. After cooling, the material was analysed by X-ray diffraction, which revealed the β-SiC crystalline phase and a little residual silicon (figure 5). This material had a mesopore volume of 0.43 cm3/g and 0.62 cm3/g for the pores with a diameter of between 6 nm and 50 nm and between 6 nm and 100 nm respectively. Its specific surface area determined by the BET technique was 48 m2/g including 4 m2/g of microporous surface area measured by the t-plot technique.

The pore distributions (determined by mercury intrusion) of these various samples are set out in figure 6. The shift of the peak of the distribution of the diameters of mesopores towards higher diameters when changing from the at least partially crosslinked resin preform (A) to the carbon preform (B) and finally to the β-SiC shaped piece (C) is noted.

Figure 7b shows a micrograph (SEM) of the β-SiC product obtained.

Table 1

Figure imgf000030_0001

"Resin" means: sample (which may, where applicable contain silicon) dried and crosslinked.

"Carbon" means: a pyrolysed sample (which may, where applicable, contain silicon).

The values of the mesopore volume are "as measured on the sample", the values between parentheses have been recalculated in "cm3 per gram of carbon" by multiplying the "values as measured on the sample" by (28+12)/12, the Si/C molar ratio in the carbon preforms being approximately 1 .

"SiC" means: the final β-SiC material.

"ND" means: not determined.

"SiC(1 )" means: as obtained, with excess of carbon.

"SiC(2)" means: after combustion of the excess carbon. Example 6 (comparative):

A 10% Co/SiC catalyst was prepared comprising an active phase of cobalt (deposited by a method described in more detail below) on a microporous β-SiC carrier having a BET specific surface area of approximately 58 m2/g, including 27 m2/g of micropores.

After the deposition of the active phase on the carrier that was in the form of grains, the specific surface area measured was no more than 24 m2/g. Figure 8 shows the pore distributions of the starting SiC sample (curve A), as well as that of the catalyst after deposition of 10% by mass of Co (curve B). The small-diameter pores (micropores) present on the original carrier disappeared after deposition of the active phase, and are therefore of no use for the Fischer-Tropsch catalytic reaction or other reaction involving at least one liquid phase; on the other hand, their contribution to the BET surface area is significant. This example therefore shows that the microporosity of the support is not an important parameter for a catalyst very heavily loaded in the active phase (as are normally the catalysts used for the Fischer-Tropsch synthesis), since the active phase has a tendency to block access to the micropores. In the example, the 10% Co charge is rather low for a Fischer-Tropsch catalyst.

In this example, the active phase of cobalt was deposited by the following method: an aqueous solution of cobalt nitrate was prepared, which is impregnated on the SiC by the porous volume method. The concentration of the cobalt nitrate is calculated so as to obtain the required cobalt load in the final catalyst. The solid was then dried in ambient air for 4 hours and then stoved at 1 10°C for 8 hours. It then underwent calcination in air at

350°C (slope of 2°C/min) for 2 hours in order to obtain the oxygen precursor of the catalyst, Co304/SiC. The 10% Co catalyst was obtained by reduction of the oxide precursor under hydrogen flow at 300°C (slope of 3°C/min) for 6 hours. Example 7 (according to the invention):

A mesoporous phenolic resin commercialised by the company MAST Carbon (Basingstoke, UK, commercial reference: TE7) was provided as a powder with a mean grain size of 40 μηη. 100 parts by mass of this resin were mixed with 104 g of metallic silicon powder with a mean grain size of 3 μηη and as much water as needed to prepare a paste. This mixture was treated for 3 hours at 800°C under argon in order to transform the phenolic resin into carbon (pyrolysis). The material obtained had a mesopore volume of 0.19 cm3/g and 0.43 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm. Per gram of carbon the mesopore volume was thus 0.63 cm3/g and 1 .43 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm. The same initial mixture was treated for one hour at 1360°C under argon flow. The obtained product was characterised by X-ray diffraction and showed the presence of beta silicon carbide as the only crystalline phase (see figure 9). It had a mesopore volume of 0.28 cm3/g and 0.55 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm, and a BET specific surface area of 1 14 m2/g, including 62 m2/g attributed to micropores. This significant microporous surface area is attributed to the presence of residual pyrolytic carbon.

The obtained β-SiC was then oxidised for 3 h in air at 600°c in order to burn the residual carbon present after the SiC synthesis. This operation led to a mass loss (attributed to the burning off of excess carbon) of 5.6%. The obtained product had a mesopore volume of 0.1 1 cm3/g and 0.47 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm, and a BET specific surface area of 32 m2/g, without any measurable microporous surface. Figure 10 shows the pore distribution obtained by mercury intrusion for the as-pyrolysed product and for the final SiC product (after burning off of excess carbon).

Example 8 (according to the invention): Mesoporous carbon balls as used in Example 4 were activated under a stream of C02

(this step had been carried out by their supplier) in order to increase their mesoporous volume from 0.24 cm3/g to 0.56 cm3/g for pores with a diameter of between 6 nm and 50 nm, and from 0.28 cm3/g to 0.57 cm3/g for pores with a diameter of between 6 nm and 100 nm (measurement carried out by mercury intrusion). Their specific BET surface area was 151 1 m2/g including 1322 m2/g attributed to the micropores. The pore distributions of carbon before and after activation are compared on Figure 1 1 .

100 parts by mass of these activated carbon balls were dry mixed with 466 parts by mass of silicon powder (d50 = 3.5 μηη). The mixture was heated under an argon stream at 1360°C for one hour. After cooling the SiC balls were separated from the residual powder containing non-reacted excess silicon by washing with water on a sieve with a sieve opening of about δθμηι.

The obtained product had a mesopore volume of 0.38 cm3/g and 0.43 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm. The pore distribution is shown on Figure12; it is perfectly monomodal. Their specific BET surface area was 56 m2/g including no more than 3 m2/g attributed to the micropores as determined by the t-plot approach.

As can be seen from Figure 13, the SiC balls (figure 13b) have conserved the perfectly spherical shape of the initial carbon balls (figure 13a). Figure 13b also shows the presence of a few agglomerates constituted by residual powder that had been imperfectly eliminated during the washing and sieving operation.

These SiC balls have been oxidised during three hour at 700°C in air, in order to remove residual carbon. The obtained product conserves a mesopore volume of 0.35 cm3/g and 0.42 cm3/g for the pores with a diameter respectively between 6 nm and 50 nm and between 6 nm and 100 nm. Its BET specific surface area was 51 m2/g.

Figure 13 shows an image obtained by scanning electron microscopy of the carbon balls used in Example 8 (figure 13a) and of the SiC balls obtained in Example 8 (figure 13b). The white bar in the lower right edge of the photograph indicated the length of 100 μηη.

Claims

1 . Method for manufacturing a β-SiC shaped material, such as a shaped piece, comprising mesopores with a diameter of between 6 nm and 100 nm representing a mesopore volume (determined by mercury intrusion porosimetry) greater than 0.35 cm3/g and preferably greater than 0.40 cm3/g, said method comprising the transformation of a mesoporous carbon preform with at least one silicon source into silicon carbide (β-SiC), said silicon source being able to be incorporated in said preform and/or contributed from outside, said transformation taking place in a non-oxidising atmosphere at a temperature preferably lying between 1 100°C and 1400°C, said carbon preform having mesopores with a diameter of between 6 nm and 100 nm with a mesopore volume greater than 0.35 cm3 per gram of carbon (preferably greater than 0.45 cm3 per gram of carbon, and even more preferentially greater than 0.55 cm3 per gram of carbon).
2. Method according to claim 1 , characterised in that said method comprises the steps of
(a) pyrolysing a mesoporous carbon precursor comprising at least one silicon source for obtaining a mesoporous carbon preform containing silicon; (b) transforming said mesoporous preform into mesoporous β-SiC by reaction with materials comprising silicon in a non-oxidising atmosphere at a temperature preferably lying between 1 100°C and 1400°C.
3. Method according to claim 2, characterized in that between the pyrolysis step (a) and the transformation step (b) the pyrolyzed material is activated in order to increase the specific mesopore volume per gram of carbon, preferably by steam activation or C02 activation, either non catalytic or catalytic.
4. Method according to any one of claims 1 to 3, characterised in that said mesoporous carbon preform was produced from a mesoporous carbon precursor that is a mesoporous phenolic resin, preferably a phenolic plastic, and even more preferentially selected from the group formed by mesoporous resoles, mesoporous novolaks and mixtures of the two.
5. Method according to any one of claims 1 to 4, characterised in that said silicon source is selected from a group formed by metallic silicon, silica, silicon compounds and mixtures thereof.
6. Method according to any one of claims 1 to 5, characterised in that said silicon source is intimately mixed with said mesoporous carbon precursor.
7. Method according to claim 6, characterised in that a preform is prepared from the mixture between said mesoporous carbon precursor and said silicon source.
8. Method according to any one of claims 2 to 7, characterised in that said silicon source is incorporated in said mesoporous carbon precursor before the shaping leading to said preform.
9. Method according to claim 7 or according to claim 8 dependent on claim 7, characterised in that said preform is obtained by a shaping method selected from the group formed by extrusion, pressing of dough, atomisation, granulation, crushing, powder pressing, emulsion, pouring in moulds, coating, or by a combination of these methods.
10. Method according to claim 7, or according to claim 8 dependent on claim 7, or according to claim 9, characterised in that said mesoporous carbon precursor is, before the shaping leading to said preform, in a crosslinked, partially crosslinked and/or non- crosslinked form.
1 1 . β-SiC shaped material, such as a shaped piece, obtainable by the method according to any one of claims 1 to 10, characterised in that it has mesopores with a diameter of between 6 nm and 100 nm corresponding to a mesopore volume of at least 0.35 cm3/g, preferably at least 0.40 cm3/g and even more preferentially at least 0.45 cm3/g (determined by mercury intrusion porosimetry).
12. Shaped material, such as a shaped piece, according to claim 1 1 , characterised in that it has a mesoporous surface area of at least 20 m2/g, preferably at least 30 m2/g and even more preferentially at least 45 m2/g.
13. Use of a shaped material, such as a shaped piece, according to any one of claims 1 1 to 12 as a catalyst carrier for reactions involving at least one liquid phase.
14. Use according to claim 13, for reactions in an aggressive environment, and in particular for reactions aimed at converting biomass.
15. Use of a shaped material, such as a shaped piece, according to either one of claims 1 1 or 12 as a catalyst carrier for the Fischer-Tropsch reaction.
16. A method of preparing a catalyst precursor comprising the steps of:
- preparing a catalyst support in the form of beta-SiC shaped material according to any of claims 1 to 10; and
- introducing a catalyst precursor compound of an active catalyst component onto and/or into said catalyst support.
17. A catalyst precursor comprising:
- a catalyst support in the form of a beta-SiC shaped material according to claim 1 1 ; and - a catalyst precursor compound of an active catalyst component supported by the catalyst support.
18. A method of preparing a catalyst including the steps of:
- preparing a catalyst precursor using the method of claim 16; and
- reducing the catalyst precursor, thereby activating the catalyst precursor and obtaining the catalyst.
19. A catalyst comprising:
- a catalyst support in the form of a beta-SiC shaped material according to claim 1 1 , and - an active catalyst component supported by the catalyst support.
20. A hydrocarbon synthesis process comprising contacting hydrogen with carbon monoxide at a temperature above 100°C (preferably from 180 to 250°C, and still more preferably from 220 to 230°C) and a pressure of at least 10 bar (preferably from 10 to 70 bar) with catalyst as claimed in claim 19 in order to produce hydrocarbons and optionally oxygenates of hydrocarbons.
21 . The process of claim 20 which includes a hydroprocessing step for converting the hydrocarbons and optionally oxygenates thereof to liquid fuels and/or chemicals.
PCT/EP2014/063503 2013-06-27 2014-06-26 Method for manufacturing shaped beta-sic mesoporous products and products obtained by this method WO2014207096A1 (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
FR1356189A FR3007673A1 (en) 2013-06-27 2013-06-27 Method for manufacturing shaped products mesoporous beta-sic and products obtained by such process
FR1356189 2013-06-27
FR1360514 2013-10-29
FR1360514 2013-10-29

Publications (1)

Publication Number Publication Date
WO2014207096A1 true true WO2014207096A1 (en) 2014-12-31

Family

ID=51162725

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/EP2014/063503 WO2014207096A1 (en) 2013-06-27 2014-06-26 Method for manufacturing shaped beta-sic mesoporous products and products obtained by this method

Country Status (1)

Country Link
WO (1) WO2014207096A1 (en)

Citations (22)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0313480B1 (en) 1987-10-19 1992-05-06 Pechiney Electrometallurgie Method for the production of silicon carbide with a high specific surface and its use in high-temperature catalytic reactions
EP0543752A1 (en) * 1991-11-21 1993-05-26 PECHINEY RECHERCHE (Groupement d'Intérêt Economique régi par l'Ordonnance du 23 Septembre 1967) Process for preparing metal carbides of high specific surface from activated carbon foams
EP0440569B1 (en) 1990-01-29 1996-08-14 PECHINEY RECHERCHE (Groupement d'Intérêt Economique régi par l'Ordonnance du 23 Septembre 1967) Process for obtaining refractory carbide based porous solid bodies, using organic compounds and a metal or metalloid
US5576466A (en) 1993-11-18 1996-11-19 Pechiney Recherche Process for the isomerisation of straight hydrocarbons containing at least 7 carbon atoms using catalysts with a base of molybdenum oxycarbide
EP0624500B1 (en) 1993-05-11 1997-04-16 Deutsche Bahn Ag Vehicle for inspection and repair
EP0624560B1 (en) 1993-05-13 2000-07-19 PECHINEY RECHERCHE (Groupement d'Intérêt Economique régi par l'Ordonnance du 23 Septembre 1967) Preparation of silicium carbide foam from a polyurethane foam impregnated with silicium-containing resin
US6130184A (en) 1997-12-30 2000-10-10 Shell Oil Company Cobalt based fischer-tropsch catalyst
US6184178B1 (en) 1997-01-13 2001-02-06 Pechiney Recherche Catalyst support with base of silicon carbide with high specific surface area in granulated form having improved mechanical characteristics
CN1401564A (en) 2002-08-19 2003-03-12 中国科学院山西煤炭化学研究所 Mesoporous silicon carbide material and mfg. method thereof
WO2004007074A1 (en) 2002-07-09 2004-01-22 Sicat Method for preparing catalysts for heterogeneous catalysis by multiple-phase impregnation, catalysts and use of said catalysts
US20040024074A1 (en) * 2000-08-09 2004-02-05 Tennison Stephen Robert Porous carbons
FR2860992A1 (en) * 2003-10-16 2005-04-22 Sicat Production of beta silicon carbide foam filter material used for removing particulates from diesel engine exhaust gases comprises using polyurethane foam with at least two zones of different pore size distribution
WO2005038204A1 (en) 2003-10-16 2005-04-28 Sicat Catalytic filter made from silicon carbide ($g(b)-sic) for the combustion of soot from exhaust gases of an internal combustion engine
WO2005073345A1 (en) 2003-12-31 2005-08-11 Total France Method for converting a synthesis gas into hydrocarbons in the presence of beta-sic and the effluent of said method
WO2007000506A1 (en) 2005-06-27 2007-01-04 Total S.A. Method of converting a synthesis gas into hydrocarbons in the presence of sic foam
WO2010043783A1 (en) * 2008-10-13 2010-04-22 Sicat Open three-dimensional structure with high mechanical resistance
EP2204235A1 (en) * 2008-12-19 2010-07-07 Total Petrochemicals Research Feluy Catalyst and process for selective hydrogenation of alkynes and dienes
US7910082B2 (en) 2008-08-13 2011-03-22 Corning Incorporated Synthesis of ordered mesoporous carbon-silicon nanocomposites
FR2950897A1 (en) * 2009-10-06 2011-04-08 Inst Francais Du Petrole Hydrocracking hydrocarbon charges comprises using catalyst comprising hydro-dehydrogenating metal comprising metals of group VIB and/or group VIII of periodic table and composite support comprising Y-type zeolite and silicon carbide
WO2012038621A1 (en) 2010-09-23 2012-03-29 Centre National De La Recherche Scientifique (C.N.R.S.) Process using a plate reactor for fischer-tropsch synthesis
WO2012164231A1 (en) 2011-06-01 2012-12-06 Sicat Llc Catalytic process for the conversion of a synthesis gas to hydrocarbons
WO2014001697A1 (en) * 2012-06-26 2014-01-03 Sicat Llc Catalyst supports made from silicon carbide covered with tio2 for fischer-tropsch synthesis

Patent Citations (24)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0313480B1 (en) 1987-10-19 1992-05-06 Pechiney Electrometallurgie Method for the production of silicon carbide with a high specific surface and its use in high-temperature catalytic reactions
EP0440569B1 (en) 1990-01-29 1996-08-14 PECHINEY RECHERCHE (Groupement d'Intérêt Economique régi par l'Ordonnance du 23 Septembre 1967) Process for obtaining refractory carbide based porous solid bodies, using organic compounds and a metal or metalloid
EP0543752A1 (en) * 1991-11-21 1993-05-26 PECHINEY RECHERCHE (Groupement d'Intérêt Economique régi par l'Ordonnance du 23 Septembre 1967) Process for preparing metal carbides of high specific surface from activated carbon foams
EP0624500B1 (en) 1993-05-11 1997-04-16 Deutsche Bahn Ag Vehicle for inspection and repair
EP0624560B1 (en) 1993-05-13 2000-07-19 PECHINEY RECHERCHE (Groupement d'Intérêt Economique régi par l'Ordonnance du 23 Septembre 1967) Preparation of silicium carbide foam from a polyurethane foam impregnated with silicium-containing resin
US5576466A (en) 1993-11-18 1996-11-19 Pechiney Recherche Process for the isomerisation of straight hydrocarbons containing at least 7 carbon atoms using catalysts with a base of molybdenum oxycarbide
EP0952889B1 (en) 1997-01-13 2003-12-17 Centre National De La Recherche Scientifique Catalyst support with base of silicon carbide with high specific surface area in granulated form having improved mechanical characteristics
US6184178B1 (en) 1997-01-13 2001-02-06 Pechiney Recherche Catalyst support with base of silicon carbide with high specific surface area in granulated form having improved mechanical characteristics
US6130184A (en) 1997-12-30 2000-10-10 Shell Oil Company Cobalt based fischer-tropsch catalyst
US8227518B2 (en) 2000-08-09 2012-07-24 British American Tobacco (Investments) Ltd. Porous carbons
US20040024074A1 (en) * 2000-08-09 2004-02-05 Tennison Stephen Robert Porous carbons
WO2004007074A1 (en) 2002-07-09 2004-01-22 Sicat Method for preparing catalysts for heterogeneous catalysis by multiple-phase impregnation, catalysts and use of said catalysts
CN1401564A (en) 2002-08-19 2003-03-12 中国科学院山西煤炭化学研究所 Mesoporous silicon carbide material and mfg. method thereof
WO2005038204A1 (en) 2003-10-16 2005-04-28 Sicat Catalytic filter made from silicon carbide ($g(b)-sic) for the combustion of soot from exhaust gases of an internal combustion engine
FR2860992A1 (en) * 2003-10-16 2005-04-22 Sicat Production of beta silicon carbide foam filter material used for removing particulates from diesel engine exhaust gases comprises using polyurethane foam with at least two zones of different pore size distribution
WO2005073345A1 (en) 2003-12-31 2005-08-11 Total France Method for converting a synthesis gas into hydrocarbons in the presence of beta-sic and the effluent of said method
WO2007000506A1 (en) 2005-06-27 2007-01-04 Total S.A. Method of converting a synthesis gas into hydrocarbons in the presence of sic foam
US7910082B2 (en) 2008-08-13 2011-03-22 Corning Incorporated Synthesis of ordered mesoporous carbon-silicon nanocomposites
WO2010043783A1 (en) * 2008-10-13 2010-04-22 Sicat Open three-dimensional structure with high mechanical resistance
EP2204235A1 (en) * 2008-12-19 2010-07-07 Total Petrochemicals Research Feluy Catalyst and process for selective hydrogenation of alkynes and dienes
FR2950897A1 (en) * 2009-10-06 2011-04-08 Inst Francais Du Petrole Hydrocracking hydrocarbon charges comprises using catalyst comprising hydro-dehydrogenating metal comprising metals of group VIB and/or group VIII of periodic table and composite support comprising Y-type zeolite and silicon carbide
WO2012038621A1 (en) 2010-09-23 2012-03-29 Centre National De La Recherche Scientifique (C.N.R.S.) Process using a plate reactor for fischer-tropsch synthesis
WO2012164231A1 (en) 2011-06-01 2012-12-06 Sicat Llc Catalytic process for the conversion of a synthesis gas to hydrocarbons
WO2014001697A1 (en) * 2012-06-26 2014-01-03 Sicat Llc Catalyst supports made from silicon carbide covered with tio2 for fischer-tropsch synthesis

Non-Patent Citations (9)

* Cited by examiner, † Cited by third party
Title
"Controlled porosity [beta]-Silicon Carbide (SiC) for innovative catalyst support solutions", 1 September 2012 (2012-09-01), XP055092331, Retrieved from the Internet <URL:http://media.wix.com/ugd/8aa046_eb90e3e08069f9f61d006a2c2bcf31e4.pdf> [retrieved on 20131209] *
C H BARTHOLOMEW; R J FERRAUTO: "Fundamentals of Industrial Catalytic Processes", 2006
F ROUQUEROL ET AL.: "Pure & Applied Chemistry", IUPAC, article "Texture des mat6riaux pulvérulents ou poreux"
J AMERICAN CHEMICAL SOCIETY, vol. 60, 1939, pages 309 - 319
K HAUFFE; S R MORRISON: "Adsorption", 1974, pages: 19 - 23
P NGUYEN; C PHAM: "Innovative porous SiC-based materials: From nanoscopic understandings to tunable carriers serving catalytic needs", APPLIED CATALYSIS A: GENERAL, vol. 391, 2011, pages 443 - 454
PATRICK NGUYEN ET AL: "Innovative porous SiC-based materials: From nanoscopic understandings to tunable carriers serving catalytic needs", APPLIED CATALYSIS A: GENERAL, ELSEVIER SCIENCE, AMSTERDAM, NL, vol. 391, no. 1, 27 July 2010 (2010-07-27), pages 443 - 454, XP028360600, ISSN: 0926-860X, [retrieved on 20100806], DOI: 10.1016/J.APCATA.2010.07.054 *
PURE & APPLIED CHEMISTRY, vol. 66, no. 8, 1994, pages 1739 - 1758
S R TENNISON, APPLIED CATALYSIS A: GENERAL, vol. 173, 1998, pages 289 - 311

Similar Documents

Publication Publication Date Title
Kim et al. Effect of metal particle size on coking during CO2 reforming of CH4 over Ni–alumina aerogel catalysts
Rezaei et al. CO2 reforming of CH4 over nanocrystalline zirconia-supported nickel catalysts
US4448896A (en) Hydrogenation catalyst for desulfurization and removal of heavy metals
US6228803B1 (en) Method of making mesoporous carbon
Srinivas et al. Exceptional CO 2 capture in a hierarchically porous carbon with simultaneous high surface area and pore volume
US4978649A (en) Porous carbonaceous material
Lua et al. Preparation and characterization of chars from oil palm waste
Li et al. Facile synthesis of porous carbon nitride spheres with hierarchical three-dimensional mesostructures for CO 2 capture
Liou Evolution of chemistry and morphology during the carbonization and combustion of rice husk
Azargohar et al. Biochar as a precursor of activated carbon
Chang et al. Hydrogenation of CO2 over nickel catalysts on rice husk ash-alumina prepared by incipient wetness impregnation
Zhang et al. Preparation of activated carbon from forest and agricultural residues through CO2 activation
Rodriguez-Mirasol et al. Structural and textural properties of pyrolytic carbon formed within a microporous zeolite template
US20050112056A1 (en) Fuel reformer catalyst and absorbent materials
Wu et al. Post-enrichment of nitrogen in soft-templated ordered mesoporous carbon materials for highly efficient phenol removal and CO 2 capture
US6057262A (en) Activated carbon and process for making same
Teng et al. Preparation of activated carbons from bituminous coals with zinc chloride activation
Yi et al. Nanocrystalline LaCoO3 perovskite particles confined in SBA-15 silica as a new efficient catalyst for hydrocarbon oxidation
Maldonado-Hódar et al. Catalytic combustion of toluene on platinum-containing monolithic carbon aerogels
Vix-Guterl et al. Formation of ordered mesoporous carbon material from a silica template by a one-step chemical vapour infiltration process
Vizcaíno et al. Ethanol steam reforming on Mg-and Ca-modified Cu–Ni/SBA-15 catalysts
Zu et al. Nanoengineering super heat-resistant, strong alumina aerogels
Vergunst et al. Carbon-based monolithic structures
JP2001287905A (en) Activated carbon and method for producing the same
Liu et al. Low-temperature formation of nanocrystalline β-SiC with high surface area and mesoporosity via reaction of mesoporous carbon and silicon powder

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 14736680

Country of ref document: EP

Kind code of ref document: A1

DPE1 Request for preliminary examination filed after expiration of 19th month from priority date (pct application filed from 20040101)
NENP Non-entry into the national phase in:

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 14736680

Country of ref document: EP

Kind code of ref document: A1