WO2019100497A1

WO2019100497A1 - Porous carbon-supported fischer-tropsch synthesis catalyst, preparation method therefor, and use thereof

Info

Publication number: WO2019100497A1
Application number: PCT/CN2017/117355
Authority: WO
Inventors: 张成华; 杨勇; 李永旺; 马彩萍; 魏宇学; 王虎林; 郑洪岩
Original assignee: 中科合成油技术有限公司
Priority date: 2017-11-23
Filing date: 2017-12-20
Publication date: 2019-05-31
Also published as: CN107754793B; CN107754793A

Abstract

Disclosed are a porous carbon-supported Fischer-Tropsch synthesis catalyst, a preparation method therefor, and the use thereof. The catalyst comprises an active phase metal and a porous carbon support, wherein the porous carbon support is porous graphite or a graphene nanocapsule; the active phase metal is entrapped within a cavity of the porous graphite or the graphene nanocapsule; and the active phase metal is at least one selected from the transition metals in Group VIIIB.

Description

Porous carbon supported Fischer-Tropsch synthesis catalyst and preparation method and application thereof

Technical field

The invention relates to a porous carbon supported Fischer-Tropsch synthesis catalyst and a preparation method and application thereof, and belongs to the field of Fischer-Tropsch synthesis catalysis.

Background technique

Syngas (a mixture containing CO and H ₂ , a small amount of CO ₂ , methane and N ₂ ) can be converted into a hydrocarbon compound by the action of a catalyst. This reaction is referred to as the Fischer-Tropsch synthesis reaction, and the Group VIIIB transition metal iron, cobalt, nickel, and rhodium are the active ingredients of the catalyst commonly used in the reaction.

The Fischer-Tropsch synthesis reaction is a reaction at a high temperature (150 to 350 ° C), a high pressure (10 to 50 bar), and a strong exotherm (165 kJ/mol). One major by-product of this reaction is water. At present, the reactors suitable for the Fischer-Tropsch synthesis reaction mainly include a fixed bed, a fixed fluidized bed, and a gas-liquid-solid three-phase slurry bed. Therefore, the Fischer-Tropsch synthesis catalyst undergoes very severe mechanical and chemical stresses during the reaction, which requires the catalyst to have very high abrasion resistance.

Usually some refractory oxides, such as silica, alumina, titania and zirconia, are used as carriers for the Fischer-Tropsch synthesis catalyst. However, these carriers also bring some unavoidable disadvantages to the catalyst, such as low thermal conductivity, poor hydrothermal stability, strong surface acidity, low mechanical strength and poor wear resistance. Since the Fischer-Tropsch synthesis reaction is a strong exothermic reaction, the poor thermal conductivity of the catalyst may cause a large amount of reaction heat to remain in the catalyst particles during the reaction, resulting in over-temperature reaction of the catalyst, poor selectivity of the target product, and more serious catalyst activity. The phase sintering loses its catalytic activity, so it is very important to remove a large amount of heat of reaction released inside the catalyst particles in time. In addition, the high water partial pressure in the Fischer-Tropsch synthesis reaction is also very lethal to the catalyst. The literature (Journal of the Chemical Society-Chemical Communications, 1984, 10, pp. 629-630) reports that water has a very detrimental effect on alumina-supported catalysts. At low temperatures, low moisture pressure, the alumina support will partially It is converted to pseudo-boehmite, which causes the catalyst to pulverize. In order to improve the mechanical and chemical stability of Fischer-Tropsch synthesis catalysts, many researchers have tried to find new catalyst carriers with high thermal conductivity and high mass transfer efficiency.

Graphite or graphene is a material with a two-dimensional layer structure, has a very large specific surface area, an ultra-high thermal conductivity (2000-5000 W/m/K), and is chemically inert and has an adjustable channel. These advantages make graphite or Graphene is an ideal catalyst carrier. However, due to the weak interaction between graphite or graphene and metal, there is also a certain difficulty in the uniform dispersion of metal on the surface of graphite or graphene. Using the two-dimensional layered structure of graphite or graphene, graphite or graphene is curled into a hollow structure, and the incorporation of metal particles in the cavity can effectively suppress the agglomeration of the metal particles. Saito et al. prepared a hollow graphite cage-coated lanthanide or iron group metal particle composite by arc discharge (Yahachi Saito, Tadanobu Yoshikawa, et al., Journal of Physics and Chemistry of Solids, 54 (1993) 1849-1860). . The M@C composite material prepared by the method has a hollow bamboo-like, chain-like and tubular carbon structure, and the metal particles are embedded in the hollow carbon structure, which can effectively inhibit the sintering agglomeration of the metal particles, but the hollow carbon structure is closed inside and outside. The metal particles are large and different in size, and their use in catalysis is not seen, and the arc method has a small yield and is not suitable for mass production. Chen et al. implanted iron nanoparticles into carbon nanotubes (CNTs) by chemical caving (Wei Chen, Zhongli Fan, et al., Journal of American Chemical Society 130 (2008) 9414-9419), this Fe@CNT The iron nanoparticles of the catalyst have uniform size, high activity and excellent product selectivity in the Fischer-Tropsch synthesis reaction, but the preparation method has long preparation route, high production cost, and is not suitable for large-scale industrial production.

Summary of the invention

It is an object of the present invention to provide a Fischer-Tropsch synthesis catalyst for syngas production of a hydrocarbon compound which has a great improvement in mass transfer, heat transfer and electronic properties, thereby greatly improving its catalytic efficiency. Overcoming the above-mentioned drawbacks of the Fischer-Tropsch synthesis catalyst.

The Fischer-Tropsch synthesis catalyst provided by the invention comprises an active phase metal and a porous carbon carrier;

The porous carbon support has a structure of discontinuous or independent porous graphite or graphene nanocapsules;

The active phase metal is contained in a cavity of the porous graphite or graphene nanocapsule, and the dispersion degree thereof is high, so that the Fischer-Tropsch synthesis catalyst exhibits good catalyst activity;

The active phase metal is selected from at least one of the Group VIIIB transition metals.

The Fischer-Tropsch synthesis catalyst has excellent mass transfer and heat transfer capability, and can greatly improve the Fischer-Tropsch synthesis performance in the tubular fixed bed reaction.

The active phase metal may specifically be at least one of iron, cobalt, nickel and ruthenium;

The number of graphite layers of the porous graphite nanocapsules is not more than 10 layers; the graphene of the porous graphene nanocapsules is a single layer or a double layer;

The porous graphite or graphene nanocapsule has a cavity diameter of 1 to 30 nm;

The specific surface area of the catalyst is not less than 50 m ² /g;

The degree of dispersion of the active phase metal in the porous carbon support (referring to the percentage of surface metal atoms to total metal atoms) is from 5% to 75%, thereby allowing the catalyst to have better catalytic activity.

The mass ratio of the active phase metal to the porous support may be 0.1 to 200:100, 1.2 to 186:100, 1.2:100, 4.1:100, 4.2:100, 18.6:100, 22.3:100, 24.5:100. , 31:100, 35.5:100 or 186:100.

The Fischer-Tropsch synthesis catalyst further comprises an auxiliary metal;

The auxiliary metal may be at least one of manganese, chromium, zinc, molybdenum, copper, platinum, palladium, rhodium, iridium, gold, silver, magnesium, calcium, strontium, barium, sodium or potassium;

The mass ratio of the promoter metal to the porous carbon support may be from 0.002 to 30:100, specifically from 0.01 to 21.8:100, 0.1:100, 1.14:100, 1.8:100, 2.9:100, 4.1:100. Or 21.8:100.

The invention also provides a preparation method of the Fischer-Tropsch synthesis catalyst, comprising the following steps:

Preparing a precursor containing carbon and the active phase metal or a precursor containing carbon, the active phase metal and the promoter metal, according to the following steps (1)-(3) or (a)-(b) That is, the Fischer-Tropsch synthesis catalyst:

(1) the precursor is carbonized in a carbon-containing atmosphere to obtain a dispersed porous graphite or graphene-coated metal nanoparticle composite material;

(2) molding the multi-hole graphite or graphene-coated metal nanoparticle composite material;

(3) the porous graphite or graphene-coated metal nanoparticle composite material after molding is obtained by firing under an inert atmosphere;

(a) molding the precursor;

(b) The formed precursor is carbonized in a carbon-containing atmosphere.

In the above preparation method, the precursor may be any one of the following 1) to 6) or a mixture of two or more of the following:

1) a solution of a precursor of the active phase metal or a solution impregnated carbon material precursor of the precursor of the active phase metal and a precursor of the promoter metal;

2) a solution of the precursor of the active phase metal or a mixture of the precursor of the active phase metal and the precursor of the promoter metal and a mixture of the carbon-containing colloidal solution (having copolymer characteristics);

3) a solution of a precursor of the active phase metal or a mixture of a precursor of the active phase metal and a precursor of the promoter metal with a mixture of biomass and its derivative monomers;

4) a solution of a precursor of the active phase metal or a mixture of a precursor of the active phase metal and a precursor of the promoter metal with a mixture of organic carboxylic acids (having copolymer characteristics);

5) a solution of the active phase metal carboxylate organometallic skeleton compound or a precursor of the promoter metal impregnated with the active phase metal carboxylate organometallic skeleton compound;

6) a metallocene complex of the active phase metal or a mixture of the promoter metal and a metallocene complex of the active phase metal.

In the above preparation method, the precursor of the active phase metal is selected from any one of the following:

Ferric nitrate, ferric chloride, ferrous chloride, ferrous sulfate, ferrous acetate, iron (III) acetylacetonate, carbonyl iron, ferrocene, cobalt nitrate, cobalt chloride, cobalt formate, cobalt acetate, cobalt acetylacetonate , cobalt carbonyl, tris(ethylenediamine) cobalt chloride (III) trihydrate, nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, nickel acetylacetonate, nickel carbonyl, ruthenium chloride, ruthenium nitrate, triphenyl Phosphonium carbonyl ruthenium, ruthenium carbonyl chloride, ammonium ruthenate and nitrosyl nitrate;

The precursor of the promoter metal is selected from any one of the following:

Manganese nitrate, manganese chloride, manganese acetate, manganese acetylacetonate, manganese carbonyl, zinc nitrate, zinc chloride, zinc sulfate, zinc acetate, zinc acetylacetonate, chromium nitrate, chromium chloride, chromium sulfate, ammonium molybdate, chlorination Platinum, platinum nitrate, chloroplatinic acid, ammonium chloroplatinate, nitrosium diammonium platinum, cerium nitrate, cerium chloride, cerium sulfate, cerium acetate, triphenylphosphine cerium chloride, acetylacetone triphenylphosphine carbonyl Bismuth, palladium nitrate, palladium chloride, palladium sulfate, palladium acetate, ammonium tetrachloropalladate, ammonium hexachloropalladate, triphenylphosphine palladium, chloroantimonic acid, cesium chloride, cesium acetate, ammonium chloroantimonate, chlorine Gold, chloroauric acid, ammonium chloroaurate, silver nitrate, silver acetate, silver carbonate, magnesium nitrate, magnesium chloride, magnesium acetate, calcium nitrate, calcium chloride, calcium acetate, barium nitrate, barium chloride, barium acetate, nitric acid Sodium, sodium chloride, sodium acetate, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium nitrate, potassium chloride, potassium hydroxide, potassium carbonate, potassium hydrogencarbonate and potassium acetate.

In the above preparation method, in 1), the carbon material precursor may be a carbon carrier such as activated carbon, nano carbon fiber, carbon nanotube or carbon sphere.

In the above preparation method, in 2), the carbon-containing colloidal solution may be activated carbon sol, nano carbon fiber sol, carbon nanotube sol, graphene oxide sol, nano lignin sol, methyl cellulose sol, ethyl fiber. A sol, a propyl cellulose sol, a methyl hydroxypropyl cellulose sol or a carboxymethyl cellulose sol.

In the above production method, in 3), the biomass may be lignin, cellulose, hemicellulose, sucrose, glucose or fructose.

In the above preparation method, in 4), the organic carboxylic acid may be levulinic acid, lauric acid, oxalic acid, citric acid, 1,3,5-benzenetricarboxylic acid, 1,4-phthalic acid, fumaric acid. , azobenzenetetracarboxylic acid, amino-terephthalic acid, 2,5-dihydroxyterephthalic acid, 1,4-naphthalene dicarboxylic acid, 1,5-naphthalenedicarboxylic acid or 2,6-naphthalenedicarboxylic acid Acid, etc.

In the above preparation method, in the step 5), the active phase metal carboxylate organometallic skeleton compound may be iron 1,3,5-benzenetricarboxylate, cobalt 1,3,5-benzenetricarboxylate, 1, 3 , nickel 5-benzenetricarboxylate, ruthenium 1,3,5-benzenetricarboxylate, iron 1,4-terephthalate, cobalt 1,4-terephthalate, nickel 1,4-terephthalate, 1 , 4-terephthalic acid terephthalate, iron fumarate, cobalt fumarate, nickel fumarate, barium fumarate, iron azobenzenetetracarboxylate, cobalt azobenzenetetracarboxylate, nickel azobenzenetetracarboxylate, Bismuth azobenzenetetracarboxylate, iron-amino-tereic acid, cobalt-amino-terephthalate, nickel-terephthalate, amino-terephthalate, iron 2,5-dihydroxyterephthalate , 2,5-dihydroxyterephthalate, nickel 2,5-dihydroxyterephthalate, bismuth 2,5-dihydroxyterephthalate, iron 1,4-naphthalene dicarboxylate, 1,4 -Cobalt naphthalate, nickel 1,4-naphthalene dicarboxylate, 1,4-naphthalene dicarboxylate, iron 1,5-naphthalenedicarboxylate, cobalt 1,5-naphthalene dicarboxylate, 1,5 - nickel naphthalene dicarboxylate, ruthenium 1,5-naphthalene dicarboxylate, iron 2,6-naphthalene dicarboxylate, cobalt 2,6-naphthalene dicarboxylate, nickel 2,6-naphthalenedicarboxylate or 2,6 - Naphthalene dicarboxylate or the like.

In the above preparation method, in 6), the metallocene complex of the active phase metal may be ferrocene, cobaltocene, ferrocene or ferrocene.

In the above preparation method, the precursor may be prepared by mixing with a carbon-containing precursor by dipping, coprecipitation, water/solvent thermal synthesis, chemical vapor deposition, and/or atomic layer deposition.

As an example of the impregnation method, the precursor of the active phase metal and the precursor of the promoter metal may be supported by a co-impregnation or a stepwise impregnation method at a suitable temperature, for example, room temperature (eg, 15 ° C to 40 ° C). On carbon-containing precursors. Wherein the exemplary co-impregnation method comprises mixing the precursor of the active phase metal and the precursor of the promoter metal in their composition ratio in the catalyst and dissolving in a solvent to form an impregnation solution, and then impregnating the impregnation solution On carbon-containing precursors. An exemplary stepwise impregnation method is to separately dissolve the precursor of the active phase metal and the precursor of the promoter metal in a solvent to form a separate impregnation solution, and then immersed stepwise on the carbonaceous precursor. Among them, the impregnation may be an equal volume impregnation or an excess impregnation. An equal volume impregnation means that the volume of the impregnation solution is equal to the saturated water absorption volume of the support; excessive impregnation means that the volume of the impregnation solution is greater than the saturated water absorption volume of the support. For example, by co-impregnating an activated carbon, a nanocarbon fiber, a carbon nanotube, a graphene oxide, an organometallic framework compound, or a mixture thereof with an impregnation solution formed from a precursor of a precursor of an active metal and/or a metal of a promoter or The active phase metal and the promoter metal are supported on the carbon-containing precursor by stepwise impregnation.

The solvent for forming the impregnation solution, the sol, and the polymer solution may be water, methanol, methylamine, dimethylamine, N,N-dimethylformamide, N-methylformamide, formamide, ethanol, and ethylene. One of alcohol, diethyl ether, ethylamine, acetonitrile, acetamide, propanol, acetone, propionitrile, tetrahydrofuran, dioxane, butanol, pyridine, morpholine, quinoline, toluene, xylene, heptane or Any mixture of two or more, but is not limited thereto.

Alternatively, the precursor of the active phase metal and the precursor of the promoter metal can be converted to a hydrated hydroxide and oxide form by a coprecipitation method onto the carbon-containing precursor. Wherein the exemplary coprecipitation method comprises mixing the precursor of the active phase metal and the precursor of the promoter metal in their composition ratio in the catalyst and dissolving in a solvent to form a mixed salt solution; The solution is mixed with the carbonaceous precursor powder according to the catalyst composition ratio and stirred to form a uniformly dispersed suspension; the suspension is mixed with the alkaline precipitant solution, precipitated, allowed to stand, filtered, and washed to obtain a catalyst precursor. For example, by mixing a salt solution with activated carbon, carbon nanofibers, carbon nanotubes, graphene oxide, lignin, cellulose, hemicellulose, methyl cellulose, ethyl cellulose, propyl cellulose, methyl Hydroxypropyl cellulose, carboxymethyl cellulose, sucrose, glucose, fructose, levulinic acid, lauric acid, oxalic acid, citric acid, 1,3,5-benzenetricarboxylic acid, 1,4-phthalic acid, Fumar One or a mixture of two or more of an acid, azobenzenetetracarboxylic acid, amino-terephthalic acid, 2,5-dihydroxyterephthalic acid, an organometallic skeleton compound forms a suspension, followed by alkaline precipitation The solution solution is coprecipitated, and the active metal and the promoter metal are uniformly mixed with the carbon-containing precursor to form a carbon-containing metal precursor.

The alkaline precipitant solution may be an alkali metal hydroxide solution, such as an aqueous solution of sodium hydroxide and/or potassium hydroxide; or an alkali metal carbonate or bicarbonate solution such as sodium carbonate or sodium hydrogencarbonate. An aqueous solution of potassium carbonate and/or potassium hydrogencarbonate; or an aqueous ammonia solution, an aqueous solution of ammonium carbonate or an aqueous solution of ammonium hydrogencarbonate; preferably an aqueous solution of ammonia.

Alternatively, the precursor of the active phase metal and the precursor of the promoter metal may be converted into a metal, a hydrated metal hydroxide, a hydrated metal oxide, a metal carboxylate, etc. by a water/solvent thermal synthesis method. On carbon-containing precursors. For example, the precursor of the active phase metal and/or the precursor of the promoter metal may be combined with activated carbon, carbon nanofibers, carbon nanotubes, graphene oxide, lignin, cellulose, hemicellulose, Cellulose, ethyl cellulose, propyl cellulose, methyl hydroxypropyl cellulose, carboxymethyl cellulose, sucrose, glucose, fructose, levulinic acid, lauric acid, oxalic acid, citric acid, 1,3, 5-benzenetricarboxylic acid, 1,4-phthalic acid, fumaric acid, azobenzenetetracarboxylic acid, amino-terephthalic acid, 2,5-dihydroxyterephthalic acid or a mixture thereof in a solvent to form a mixture The liquid is subjected to water/solvent thermal synthesis to uniformly mix the active phase metal and the promoter metal with the carbon-containing precursor to form a carbon-containing metal precursor.

The above mixed salt solution or alkali metal hydroxide solution or alkali metal carbonate solution or alkali metal hydrogencarbonate solution and the solvent used in the water/solvent thermal synthesis method may be water, methanol, methylamine or dimethyl Amine, N,N-dimethylformamide, N-methylformamide, formamide, ethanol, ethylene glycol, ethylamine, acetonitrile, acetamide, propanol, propionitrile, tetrahydrofuran, dioxane, butyl One of alcohol, pyridine, morpholine, quinoline or a mixture of any two or more thereof, but is not limited thereto.

Alternatively, the precursor of the active phase metal and the precursor of the promoter metal may be converted to a metal, a metal carbide, a metal nitride, a metal oxide or the like by a chemical vapor deposition method to be deposited on the carbon-containing precursor. For example, the organometallic compound containing the active metal and the promoter metal can be heated under high vacuum (10 ^-1 Pa to 10 ^-6 Pa) or atmospheric pressure (ie, one atmosphere) and chemical vapor deposition. The active metal and promoter metals are deposited on activated carbon, nanocarbon fibers, carbon nanotubes, graphene oxide, organometallic framework compounds, or mixtures thereof.

Alternatively, the precursor of the active phase metal and the promoter metal may be converted to a metal, a metal carbide, a metal nitride, a metal oxide or the like by an atomic layer deposition method to be deposited on the carbon-containing precursor. For example, the active metal and the promoter metal can be deposited on the active layer by atomic layer deposition by alternately adsorbing a gas compound containing an active metal and a promoter metal and an oxidant in a high vacuum (10 ^-1 Pa to 10 ^-6 Pa) chamber. Carbon, carbon nanofibers, carbon nanotubes, graphene oxide, and organometallic framework compounds.

In the above preparation method, the precursor may be crushed by a physical grinding method, preferably at least one of rolling, impacting, grinding, mashing and breaking, more preferably impact and/or abrasion;

The particle size of the powdered carbonaceous and metallic precursor obtained by milling is preferably less than 100 microns, more preferably less than 1 micron.

In the above preparation method, the carbon-containing atmosphere may be a mixed gas of a carbon-containing gas and an inert gas;

The carbonaceous gas is methane, ethane, ethylene, acetylene, propane, propylene, CO and/or syngas (CO+H ₂ );

In the carbon-containing atmosphere, the volume concentration of the carbon-containing gas is 0.5 to 100%;

The inert gas is selected from at least one of nitrogen, helium, argon, helium, and neon.

The carbonization temperature is 350 to 1100 ° C and the time is 1 to 10 hours.

In the above production method, the calcination temperature is 300 to 500 ° C and the time is 1 to 10 hours.

In the above preparation method, in the step (2) or (a), the molding step uses cellulose ether as a molding agent;

The cellulose ether is selected from functional group-substituted cellulose, preferably from a carboxylic acid group, a hydroxyl group, an alkyl functional group, and a combination functional group thereof, preferably from a methyl group, an ethyl group, a propyl group, and the like. Combined functional group.

The cellulose ether is selected from the group consisting of carboxyethyl cellulose, carboxymethyl cellulose, carboxymethyl hydroxyethyl cellulose, carboxyethyl hydroxymethyl cellulose, hydroxyethyl cellulose, hydroxymethyl cellulose, and hydroxy Propylcellulose, hydroxymethyl-methylcellulose, hydroxymethyl-ethylcellulose, hydroxyethyl-ethylcellulose, methylcellulose, ethylcellulose, propylcellulose, ethyl- One of carboxymethylcellulose, hydroxy-ethylcellulose in hydroxy-ethyl-propylcellulose.

In the step (2) or (a), the molding method used in the molding step may be compression molding, rotational molding, extrusion molding or oil molding; the shape of the catalyst precursor after molding may be granular, microspherical, Sheet, strip, column, ring, porous sheet or clover.

The Fischer-Tropsch synthesis catalyst of the invention can be used in the preparation of hydrocarbon compounds by catalytic synthesis gas in a Fischer-Tropsch synthesis reaction.

As a preferred example, the Fischer-Tropsch synthesis catalyst of the present invention can be directly applied to the Fischer-Tropsch synthesis reaction, and the catalyst can be previously reduced in a reducing atmosphere before being applied to the Fischer-Tropsch synthesis reaction. The reducing atmosphere may be a pure hydrogen atmosphere, a CO atmosphere, a synthesis gas atmosphere, an ammonia gas atmosphere, a diluted hydrogen atmosphere, a diluted CO atmosphere, a diluted synthesis gas atmosphere, and a diluted ammonia gas atmosphere. The volume ratio of H ₂ to CO in the syngas is from 0.011 to 1000:1. Each of the diluted reducing atmospheres may further contain nitrogen, argon, helium, CO ₂ and/or CH ₄ in addition to the respective reducing atmospheres, and the volume concentration of the reducing gas in each of the diluted atmospheres is greater than 10%. It is preferably greater than 25%, more preferably 50%, most preferably 75%, and most preferably greater than 90%. The Fischer-Tropsch synthesis catalyst is subjected to further pretreatment to form a reduced-state Fischer-Tropsch synthesis catalyst having a certain degree of reduction (ie, a metal phase, a metal carbide as a percentage of the total active phase metal), preferably a reduced state Fischer-Tropsch synthesis catalyst The degree of reduction is at least greater than 60%, preferably greater than 75%, and most preferably greater than 85%.

The volume ratio of H ₂ to CO in the synthesis gas of the Fischer-Tropsch synthesis reaction is from 0.5:1 to 3.0:1, preferably from 1.0:1 to 2.5:1, more preferably from 1.2:1 to 2.2:1, most preferably from 1.5:1. 2.0:1. The Fischer-Tropsch synthesis reaction can be carried out in a continuous or batch reaction process. The Fischer-Tropsch synthesis reaction may employ one or more fixed bed reactors, microchannel reactors, continuously stirred slurry bed tank reactors, jet circulation reactors, slurry bubble column reactors or fluidized bed reactors. get on. The pressure of the Fischer-Tropsch synthesis reaction is 1.0 to 6.0 MPa, and the temperature is 120 to 350 °C. When the Fischer-Tropsch synthesis reaction is carried out in a continuous reaction process, the reaction weight hourly space velocity is from 100 to 60,000 NL/kg/h.

For example, when the Fischer-Tropsch synthesis catalyst is a cobalt catalyst, the volume ratio of H ₂ to CO in the synthesis gas is from 1.0:1 to 3.0:1, preferably from 1.5:1 to 2.5:1, and most preferably from 1.8:1 to 2.2. :1. The pressure of the Fischer-Tropsch synthesis reaction is 1.0 to 6.0 MPa, preferably 1.5 to 4.5 MPa, and most preferably 2.0 to 3.0 MPa. The temperature of the Fischer-Tropsch synthesis reaction is 180 to 280 ° C, preferably 200 to 260 ° C, and most preferably 220 to 240 ° C. When the Fischer-Tropsch synthesis reaction is carried out in a continuous reaction process, the reaction weight hourly space velocity is from 100 to 25,000 NL/kg/h, preferably from 1,000 to 20,000 NL/kg/h, and most preferably from 5,000 to 15,000 NL/kg/h.

Alternatively, when the Fischer-Tropsch synthesis catalyst is an iron catalyst, the volume ratio of H ₂ to CO in the synthesis gas is from 0.5:1 to 3.0:1, preferably from 1.0:1 to 2.5:1, more preferably from 1.2:1 to 2.2:1. Most preferably 1.5:1 to 2.0:1. The pressure of the Fischer-Tropsch synthesis reaction is preferably 1.0 to 6.0 MPa, preferably 1.5 to 5.5 MPa, more preferably 2.0 to 5.0 MPa, and most preferably 2.5 to 4.0 MPa. The temperature of the Fischer-Tropsch synthesis reaction is 220 to 350 ° C, preferably 240 to 330 ° C, and most preferably 260 to 300 ° C. When the Fischer-Tropsch synthesis reaction is carried out in a continuous reaction process, the reaction weight hourly space velocity is from 100 to 60,000 NL/kg/h, preferably from 1,000 to 40,000 NL/kg/h, and most preferably from 10,000 to 20,000 NL/kg/h.

Alternatively, when the Fischer-Tropsch synthesis catalyst is a rhodium catalyst, the volume ratio of H ₂ to CO in the synthesis gas is from 0.5:1 to 3.0:1, preferably from 1.0:1 to 2.5:1, more preferably from 1.2:1 to 2.2:1. Most preferably 1.5:1 to 2.0:1. The pressure of the Fischer-Tropsch synthesis reaction is 1.0 to 10.0 MPa, preferably 2.5 to 7.5 MPa, more preferably 3.0 to 6.0 MPa, and most preferably 3.5 to 5.0 MPa. The temperature of the Fischer-Tropsch synthesis reaction is 120 to 280 ° C, preferably 150 to 240 ° C, and most preferably 180 to 220 ° C. When the Fischer-Tropsch synthesis reaction is carried out in a continuous reaction process, the reaction weight hourly space velocity is 100 to 10000 NL/Kg/h, preferably 500 to 8000 NL/Kg/h, and most preferably 1000 to 5000 NL/Kg/h.

The exemplary embodiment of the invention has the following characteristics: simple catalyst preparation method, low raw material cost, low production cost and good repeatability; the catalyst of the invention has a large specific surface area (not less than 50 m ² /g) and high activity. Metal dispersion (5% to 75%), high mechanical strength (wear index of 1 to 2.0%·h ^-1 ) and excellent stability; the catalyst of the present disclosure is applied to the Fischer-Tropsch synthesis reaction A catalyst prepared by direct chemical synthesis or a catalyst comprising a conventional support (SiO ₂ or Al ₂ O ₃ ) has better synthesis gas conversion activity, hydrocarbon compound selectivity and high temperature stability.

For example, when the porous carbon-coated cobalt nanoparticle catalyst of the present invention has a reaction temperature of 200 to 280 ° C and a reaction weight hourly space velocity of 10000 NL/Kg/h, the conversion of CO can be maintained at 10% or more, C _{5 .} ⁺ Hydrocarbon selectivity is greater than 75% and methane selectivity is less than 13%. The CO conversion was tested for stable operation over 100 h: the initial reaction temperature was 220 ° C and the intensive test temperature was 250 ° C. The conversion stability of the catalyst is maintained above 0.8 and even greater than 0.9. Further, for example, when the porous carbon-coated iron nanoparticle catalyst of the present invention has a reaction temperature of 280 to 320 ° C and a reaction space velocity of 15000 NL/Kg/h or more, the conversion of CO can be maintained at 10% or more. The CO ₂ selectivity is less than 10% (even less than 5%), the C ₅ ⁺ hydrocarbon selectivity is greater than 90%, and the methane selectivity is less than 5%. The CO conversion was tested for stable operation over 100 h: the initial reaction temperature was 280 ° C, and the intensive reaction temperature was 300 ° C. The conversion stability of the catalyst is maintained above 0.8 and even greater than 0.9. Further, for example, when the porous carbon-coated ruthenium nanoparticle catalyst of the present invention has a reaction temperature of 180 to 240 ° C and a reaction space velocity of 1000 NL/Kg/h or more, the conversion of CO can be maintained at 10% or more. The CO ₂ selectivity is less than 5% (even less than 1%), the C ₅ ⁺ hydrocarbon selectivity is greater than 90%, and the methane selectivity is less than 5%. The CO conversion was tested for stable operation over 100 h: the initial reaction temperature was 180 ° C and the intensive reaction temperature was 240 ° C. The conversion stability of the catalyst is maintained above 0.9 and even greater than 0.98.

The experimental results show that the porous carbon-supported ruthenium-based, cobalt-based or iron-based catalyst provided by the present invention has a significantly increased catalytic activity, long-period stability and flexible operability in the Fischer-Tropsch synthesis reaction, especially The Fischer-Tropsch synthesis catalyst is applied to a high temperature fixed bed Fischer-Tropsch synthesis reaction. The catalyst of the present disclosure has excellent heat and mass transfer ability, and can selectively produce target hydrocarbon compounds (especially C ₅ ⁺ hydrocarbons, that is, hydrocarbons having 5 or more carbon atoms) with high selectivity, and exhibits good performance. Mechanical and chemical stability. Therefore, the catalyst is very suitable for the Fischer-Tropsch synthesis reaction. The catalyst is particularly suitable for Fischer-Tropsch synthesis reactions carried out in conventional fixed bed reactors or column reactors (with shell-and-tube heat exchanger mode) and at high space velocities.

DRAWINGS

1 is an XRD pattern of a porous carbon-supported cobalt catalyst prepared in Example 1 of the present invention.

2 is an XRD pattern of a porous carbon-supported iron catalyst prepared in Example 4 of the present invention.

3 is a TEM photograph of a porous carbon-supported cobalt catalyst prepared in Example 1 of the present invention.

4 is a TEM photograph of a carbon support remaining after removing a metal element by pickling of a porous carbon-supported cobalt catalyst prepared in Example 1 of the present invention.

Detailed ways

The experimental methods used in the following examples are conventional methods unless otherwise specified.

The materials, reagents and the like used in the following examples are commercially available unless otherwise specified.

Embodiment 1.

Weigh 44.7 g of terephthalic acid (H ₂ BDC), 1179 g of N,N-dimethylformamide (DMF), 71.5 g of cobalt sulfate heptahydrate and 4.1 g of manganese sulfate, mix, stir until dissolved, and transfer to hydrothermal synthesis. The mixture was hydrothermally synthesized at 150 ° C for 36 hours, filtered, washed and dried to obtain a CoMn-BDC organic carboxylic acid copolymer precursor (belonging to the fourth precursor) having a BET specific surface area of 331 m ² /g. 1.5 g of potassium nitrate and 44 g of deionized water were weighed into a solution, and the solution was uniformly mixed with the prepared CoMn-BDC organic carboxylic acid copolymer precursor, and dried in a 50% C ₂ H ₄ /50% N ₂ gas stream. Carbonized at 600 ° C for 2 h, carbon-coated CoMn nanocomposites were obtained. The carbon-coated CoMn nanocomposite was kneaded with 48.0 g of methyl cellulose, extruded into a strip having a diameter of 1 mm, dried at 120 ° C in a N ₂ atmosphere, and calcined at 400 ° C to obtain a catalyst, which was labeled as Exam-1. The mass composition of the catalyst element was: Co/Mn/K/C = 31:2.9: 1.2:100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1.

The XRD pattern of the catalyst prepared in this example is shown in Fig. 1. It can be seen that the characteristic structure of graphite or graphene exists in the catalyst, and the XRD diffraction peak of cobalt is a highly dispersed surface-centered cubic phase metallic cobalt characteristic structure.

The TEM photograph of the catalyst prepared in this example is shown in Fig. 3. It can be seen that the metal cobalt nanocrystal grains are uniformly embedded in the carbon matrix, and the particles are surrounded by several layers of discontinuous graphene carbon structure, indicating that the package The carbon layer of the metal-coated particles is porous graphene.

Fischer-Tropsch synthesis performance test: 0.5 g of each of the above catalysts was separately taken and diluted uniformly with 2 ml of silicon carbide, and placed in a fixed bed reactor having an inner diameter of 10 mm and a constant temperature section of 50 mm. The catalyst was reduced in H2 at 375 ° C for 6 hours and cooled to 160 ° C. Then, 62% H ₂ /31% CO / 7% Ar (volume ratio) of synthesis gas was introduced into the reactor at a pressure of 3.0 MPa, and the reactor temperature was increased to 220 ° C at a heating rate of 0.1 ° C / min. The reaction space velocity was 8000 NL/Kg/h, and the reaction was maintained for more than 100 hours. Then, the reaction temperature was raised to 260 ° C, the space velocity was adjusted to 15000 NL / Kg / h, the reaction was maintained for about 50 hours; then the temperature was lowered to 220 ° C, the space velocity was adjusted to 8000 NL / Kg / h, and the reaction was maintained for more than 24 hours. The composition of the reactor off-gas was analyzed by gas chromatography during the reaction and used to calculate the CO conversion, product selectivity and stability of the reaction. The results of the Fischer-Tropsch synthesis reaction of each of the above catalysts are shown in Table 2. The catalyst after the reaction is extracted with toluene to remove the adsorption wax, and then soaked in dilute hydrochloric acid overnight to dissolve the metal element in the catalyst, washed, filtered, and the filter sample is dried in nitrogen. The TEM photo is shown in Figure 4. The residual carbon support after removing the metal is a porous graphene capsule structure, and the middle hollow portion provides a package position for the metal nanoparticles, thereby effectively preventing the aggregation of the metal particles.

Example 2

25.2 g of 2,5-dihydroxyterephthalic acid, 63.4 g of cobalt acetate tetrahydrate, 27.5 g of tetrahydrofuran, and 18.3 g of deionized water were weighed, stirred well, dissolved, transferred to a hydrothermal synthesis kettle, and crystallized at 110 ° C for 72 h. The obtained product is filtered, washed, and dried to finally obtain a precursor of CPO-27-Co metal organic skeleton material (belonging to the fifth precursor). The CPO-27-Co precursor was carbonized in a 20% C ₂ H ₆ /80% Ar gas stream at 850 ° C for 1 h to obtain a carbon-coated Co nanocomposite. The carbon-coated Co nanocomposite was kneaded with 25.0 g of ethyl cellulose, extruded into a strip having a diameter of 1 mm, dried in a N ₂ atmosphere at 120 ° C, and calcined at 450 ° C to obtain a catalyst, which was labeled Exam-2. The mass composition of the catalyst element was: Co/C = 24.5:100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1. The Fischer-Tropsch synthesis performance test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Embodiment 3

Weigh 24.7g of cobalt nitrate hexahydrate, 5.18g of 50% manganese nitrate solution, 0.01g of platinum chloride, 50g of starch, 8g of ionized water (belonging to the 3rd kind of precursor), and mix well to obtain a mixture of metal and carbonaceous material. The precursor, extruded into a strip having a diameter of 1 mm, dried and then carbonized at 700 ° C for 1 h in a 20% C ₃ H ₆ /80% Ar gas stream to give a catalyst, labeled Exam-3. The elemental mass composition of the catalyst was: Co/Mn/Pt/C = 35.5: 1.1: 0.04: 100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1.

The Fischer-Tropsch synthesis performance test was carried out in the same manner as in Example 1, and the results are shown in Table 2.

Example 4

Weigh 482.5g of ferric chloride hexahydrate, 251.4g of trimesic acid and 375g of deionized water to prepare a solution. Stir at room temperature, put it into a stainless steel reaction tank lined with polytetrafluoroethylene, and react the reaction solution at 140 °C for 12h. After centrifugal washing and drying, a metal organic skeleton material precursor Fe-MIL-100 having a BET specific surface area of 1558 m ² /g was obtained. Weigh 70.7 g of manganese chloride tetrahydrate, 1.1 g of potassium chloride, 242.2 of glucose, and 810 g of deionized water to prepare a solution. The solution is uniformly mixed with the prepared metal organic framework Fe-MIL-100 to obtain carbon and metal. The mixture is crushed to a particle having a mesh number of 10 to 20 mesh, which is a precursor (belonging to the fifth precursor), and then carbonized at 1000 ° C for 3 hours in a 5% CO/95% N ₂ gas stream to obtain a catalyst. For Exam-4. The elemental mass composition of the catalyst is: Fe/Mn/K/C=186/19.5/2.3/100, and its XRD pattern is shown in Fig. 2, and the texture properties, dispersion, reduction degree and wear index are listed in Table 1. .

The XRD pattern of the catalyst prepared in this example is shown in Fig. 2. It can be seen that the characteristic structure of graphite or graphene exists in the catalyst, and the XRD diffraction peak of iron is a χ-Fe ₅ C ₂ characteristic structure.

Fischer-Tropsch synthesis performance test: 2 g of the above catalyst was taken separately, diluted with 2 ml of silicon carbide and uniformly mixed, and placed in a fixed bed reactor having an inner diameter of 10 mm and a constant temperature section of 50 mm. The catalyst was reduced in a syngas of 98% H ₂ /2% CO at 320 ° C for 24 hours and cooled to 220 ° C. Then, 63% H ₂ /37% CO synthesis gas was introduced into the reactor at a pressure of 3.0 MPa, and the reactor temperature was increased to 280 ° C at a heating rate of 0.1 ° C / min, and the reaction space velocity was adjusted to 12000 NL / Kg / h, keep the reaction for more than 100 hours. Then, the reaction temperature was raised to 300 ° C, the space velocity was adjusted to 25000 NL / Kg / h, the reaction was maintained for about 50 hours; then the temperature was lowered to 280 ° C, the space velocity was adjusted to 12000 NL / Kg / h, and the reaction was maintained for more than 24 hours. The composition of the reactor off-gas was analyzed by gas chromatography during the reaction and used to calculate the CO conversion, product selectivity and stability of the reaction. The results of the Fischer-Tropsch synthesis reaction are shown in Table 2.

Example 5

144.7 g of iron nitrate nonahydrate, 4.2 g of manganese nitrate hexahydrate, 2.9 g of copper nitrate, and 3.7 g of sodium nitrate were weighed and dissolved in deionized water. At the same time, 100 g of activated carbon carrier particles (20-40 mesh, BET surface area of 740 m ² /g) were weighed, and the metal salt mixed solution was impregnated into the active according to the ratio of the volume of the mixed solution of the metal salt to the water absorption volume of the activated carbon of 1:1. The carbon support was allowed to stand for 8 hours, and dried overnight at 110 ° C in a nitrogen atmosphere to obtain a metal-impregnated carbon material precursor (belonging to the first precursor). Carbonization at 550 ° C for 1 h in a 2% C ₂ H ₂ /98% Ar stream gave the catalyst, labeled Exam-5. The elemental mass composition of the catalyst was: Fe/Mn/Cu/Na/C = 18.6/0.9/1.0/1.0/100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1. The Fischer-Tropsch synthesis performance test was carried out in the same manner as in Example 4, and the results are shown in Table 2.

Example 6,

Weigh 44.7 g of terephthalic acid (H ₂ BDC), 1179 g of N,N-dimethylformamide (DMF) and 46.7 g of ferrous acetate, mix, stir until dissolved, transfer to hydrothermal synthesis kettle, water at 110 ° C The mixture was thermally synthesized for 24 hours, filtered, washed and dried to obtain a Fe-BDC metal organic carboxylic acid copolymer precursor having a BET specific surface area of 231 m ² /g. Weigh 0.9 g of copper nitrate, 1.5 g of potassium nitrate, 13.5 g of sucrose, and 74 g of deionized water to prepare a solution. The solution and the prepared Fe-BDC metal organic carboxylic acid copolymer are uniformly mixed, dried and crushed to obtain a mesh number. A carbonaceous and metal mixture precursor (belonging to the 4th precursor) of 10-20 mesh, carbonized at 900 ° C for 1 h in a 25% CO/5% H ₂ /70% N ₂ gas stream to obtain a catalyst, labeled Exam- 6. The elemental mass composition of the catalyst was: Fe/Cu/K/C = 22.3/0.6/1.2/100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1. The Fischer-Tropsch synthesis performance test was carried out in the same manner as in Example 4, and the results are shown in Table 2.

Example 7,

Weigh 5.5g of antimony trichloride (Ru content: 38%) dissolved in deionized water, weigh 40g of activated carbon carrier particles (20 ~ 40 mesh, BET surface area of 740m ² / g), according to the volume and activity of the mixed solution of metal salt The carbon water absorption volume is 1:1, the cerium salt solution is impregnated onto the activated carbon support, allowed to stand for 8 hours, and dried at 100 ° C overnight in a nitrogen atmosphere to obtain a metal-impregnated carbon material precursor (belonging to the first species). Precursor), carbonized at 650 ° C for 1 h in a 5% C ₂ H ₂ /95% He gas stream to give the catalyst, labeled Exam-7. The elemental mass composition of the catalyst was: Ru/C = 4.1/100, and its texture properties, dispersity, degree of reduction and wear index are listed in Table 1 for its texture properties, degree of reduction and degree of dispersion as listed in Table 1.

Fischer-Tropsch synthesis performance test: 20 g of the above catalyst Exam-7, 320 g of n-hexadecane was weighed into a 500 ml slurry bed stirred tank. The stirring speed of the stirring paddle was 800 rpm, and the catalyst was reduced in H ₂ at 200 ° C for 6 hours, and the temperature was lowered to 150 ° C. Then, 62% H ₂ /31% CO / 7% Ar (volume ratio) of synthesis gas was introduced into the reactor at a pressure of 10.0 MPa, the reaction space velocity was adjusted to 2000 NL / Kg / h, and the reaction was maintained for more than 100 hours. Then, the reaction temperature was raised to 200 ° C, the space velocity was adjusted to 8000 NL / Kg / h, the reaction was maintained for about 50 hours; then the temperature was lowered to 150 ° C, the space velocity was adjusted to 5000 NL / Kg / h, and the reaction was maintained for more than 24 hours. The composition of the reactor off-gas was analyzed by gas chromatography during the reaction and used to calculate the CO conversion, product selectivity and stability of the reaction. The results of the Fischer-Tropsch synthesis reaction of each of the above catalysts are shown in Table 2.

Example 8,

Weigh 33.2 g of terephthalic acid (H ₂ BDC), 12.4 g of ethylene glycol, 1179 g of N,N-dimethylformamide (DMF) and 11.3 g of antimony trichloride (Ru content: 38%), and stir until Dissolved, transferred into a hydrothermal synthesis kettle, hydrothermally synthesized at 110 ° C for 72 h, filtered, washed and dried to obtain a Ru-BDC metal organic carboxylic acid copolymer precursor (belonging to the fourth precursor). The Ru-BDC metal organic carboxylic acid copolymer was carbonized in a 10% C ₃ H ₆ /90% N ₂ gas stream at 700 ° C for 5 h to obtain a carbon-coated Ru nanocomposite. The carbon-coated Ru nanocomposite was kneaded with 87.0 g of methyl cellulose, extruded into a strip having a diameter of 1 mm, dried at 120 ° C in a N ₂ atmosphere, and calcined at 400 ° C to obtain a catalyst, which was labeled Exam-8. The mass composition of the catalyst element was: Ru/C = 1.2/100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1.

The Fischer-Tropsch synthesis performance test was carried out in the same manner as in Example 7, and the results are shown in Table 2.

Example 9,

Weigh 33.2 g of terephthalic acid (H ₂ BDC), 48.3 g of glucose, 16.8 g of potassium hydroxide, 16.5 g of ammonium chloroantimonate (Ru content 31%) and 300 g of deionized water, stir until dissolved, and transfer to water heat. The synthesis vessel was hydrothermally synthesized at 120 ° C for 24 hours, filtered, washed and dried to obtain a mixture precursor of carbon and Ru (belonging to the third precursor). The mixture precursor containing carbon and Ru was carbonized in an 8% C ₂ H ₂ /92% Ar gas stream at 500 ° C for 3 h to obtain a carbon-coated Ru nanocomposite. The carbon-coated Ru nanocomposite was kneaded with 63.0 g of methyl cellulose, extruded into a strip having a diameter of 1 mm, dried at 120 ° C in a N ₂ atmosphere, and calcined at 400 ° C to obtain a catalyst, which was labeled as Exam-9. The mass composition of the catalyst element was: Ru/K/C = 4.2/0.1/100, and its texture properties, dispersity, degree of reduction, and wear index are listed in Table 1.

Comparative example 1,

Preparation of alumina-supported cobalt catalyst by coprecipitation method: weigh 24.71g of cobalt nitrate hexahydrate, 5.18g of 50% manganese nitrate solution, 0.01g of platinum chloride dissolved in 100ml of deionized water, and then weigh 13.3g of pseudo-thin water Aluminite (produced by Shandong Aluminum Factory, containing 75 wt% of dry-base alumina) was mixed with the above solution to form a uniform suspension by ultrasonic dispersion. To the suspension, a 1 mol/L aqueous ammonia solution was added dropwise to a pH of 8 to 9 under stirring to form a precipitate. The precipitate was filtered, washed, dried overnight at 120 ° C in air, heated to 450 ° C in a muffle furnace at a heating rate of 1 ° C / min and calcined at this temperature for 5 hours to obtain a composition in the catalyst: Co / Mn/Pt/Al ₂ O ₃ = 50/10/0.06/100, labeled CE-1, and its texture properties, degree of reduction, degree of dispersion, and wear index are listed in Table 1.

The Fischer-Tropsch synthesis performance test was carried out in the same manner as in Example 4, and the results are shown in Table 2.

Table 1 The texture properties, particle size and degree of reduction of the catalysts prepared in Examples 1-9 and Comparative Example 1

Table 2 Fischer-Tropsch synthesis reactivity, selectivity and stability of the catalysts prepared in Examples 1-9 and Comparative Example 1

As shown in Table 2, the porous carbon-coated cobalt catalyst of the present invention exhibits a very high Fischer-Tropsch synthesis catalytic activity and excellent C ₅ ⁺ hydrocarbon selectivity, after a long period of more than 200 hours and above 220 ° C. After the harsh reaction at high temperature, the activity of most of the catalyst can still recover to more than 90% of the initial activity. At the same time, all porous carbon-coated cobalt catalysts showed excellent activity, abrasion resistance and reaction stability compared to the Al ₂ O ₃ supported cobalt catalyst.

Similarly, the porous carbon-coated iron catalyst prepared in the present invention exhibits higher Fischer-Tropsch synthesis catalytic activity and equally excellent C ₅ ⁺ hydrocarbon selectivity at higher reaction temperatures. After experiencing long-term and high-temperature reactions, the activity of these iron catalysts can be restored to more than 90% of the initial activity, indicating that the catalyst of the present invention has excellent stability and catalytic activity.

Similarly, the porous carbon-coated rhodium catalyst prepared in the present invention exhibits very high Fischer-Tropsch synthesis catalytic activity and extremely high C ₅ ⁺ hydrocarbon selection at lower reaction temperatures and higher reaction pressures. Sex. After experiencing long-period, high-temperature, and high-pressure reactions, the activity of these rhodium catalysts was hardly lost, indicating that the catalyst of the present invention has excellent stability and catalytic activity.

From this, it can be seen that the VIIIB cluster transition metal catalyst in which the porous carbon is a carrier disclosed by the present invention can achieve very excellent Fischer-Tropsch synthesis reaction performance.

Industrial application

The invention has the following beneficial effects:

1. The metal active phase of the catalyst of the present invention is coated in a cavity of a discontinuous or independent porous graphite or graphene nanocapsule, and a direct electronic interaction between the metal active phase and graphite or graphene, graphite or graphene Has excellent electronic additives properties.

2. The method for preparing a catalyst of the present invention uses a carbon-containing gas as a growth carbon source of porous graphite or graphene, and graphite or graphene grows along the surface of the metal nanoparticle, thereby avoiding formation of a closed hollow graphite or graphene capsule.

3. The catalyst of the invention exhibits excellent electronic properties, high thermal conductivity, resistance to physical and chemical wear, high hydrothermal stability and high mechanical strength in the Fischer-Tropsch synthesis application, and the rich nanopore structure of the catalyst can promote the active phase of the catalyst. Highly dispersed and diffused of the reactive species, whereby the catalyst has excellent Fischer-Tropsch synthesis performance: high activity, low methane selectivity and long operating life.

Claims

A Fischer-Tropsch synthesis catalyst comprising an active phase metal and a porous carbon support;

The porous carbon support is a porous graphite or graphene nanocapsule;

The active phase metal is encapsulated in a cavity of the porous graphite or graphene nanocapsule;

The active phase metal is selected from at least one of the Group VIIIB transition metals.
The Fischer-Tropsch synthesis catalyst according to claim 1, wherein the active phase metal is at least one of iron, cobalt, nickel and ruthenium;

The number of graphite layers of the porous graphite nanocapsules is not more than 10 layers; the graphene of the graphene nanocapsules is a single layer or a double layer;

The porous graphite or graphene nanocapsule has a cavity diameter of 1 to 30 nm;

The mass ratio of the active phase metal to the porous support is from 0.1 to 200:100.
The Fischer-Tropsch synthesis catalyst according to claim 1 or 2, wherein the Fischer-Tropsch synthesis catalyst further comprises an auxiliary metal encapsulated in a cavity of the porous graphite or graphene nanocapsule;

The auxiliary metal is at least one of manganese, chromium, zinc, molybdenum, copper, platinum, palladium, rhodium, iridium, gold, silver, magnesium, calcium, strontium, barium, sodium or potassium;

The mass ratio of the promoter metal to the porous carbon support is from 0.002 to 30:100.
A method of preparing a Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 3, comprising the steps of:

Preparing a precursor containing carbon and the active phase metal or a precursor containing carbon, the active phase metal and the promoter metal, according to the following steps (1)-(3) or (a)-(b) That is, the Fischer-Tropsch synthesis catalyst:

(1) the precursor is carbonized in a carbon-containing atmosphere to obtain a dispersed porous graphite or graphene-coated metal nanoparticle composite material;

(2) molding the porous graphite or graphene-coated metal nanoparticle composite material;

(3) the porous graphite or graphene-coated metal nanoparticle composite material after molding is obtained by firing under an inert atmosphere;

(a) molding the precursor;

(b) The formed precursor is carbonized in a carbon-containing atmosphere.
The production method according to claim 4, wherein the precursor is any one or a mixture of two or more of the following 1) to 6):

1) a solution of a precursor of the active phase metal or a solution impregnated carbon material precursor of the precursor of the active phase metal and a precursor of the promoter metal;

2) a precursor solution of the active phase metal or a precursor of the active phase metal and a mixture of a precursor solution of the promoter metal and a carbon-containing colloidal solution;

3) a solution of a precursor of the active phase metal or a mixture of a precursor of the active phase metal and a precursor of the promoter metal with a mixture of biomass and its derivative monomers;

4) a solution of a precursor of the active phase metal or a mixture of a precursor of the active phase metal and a precursor of the promoter metal with an organic carboxylic acid;

5) a solution of the active phase metal carboxylate organometallic skeleton compound or a precursor of the promoter metal impregnated with the active phase metal carboxylate organometallic skeleton compound;

6) a metallocene complex of the active phase metal or a mixture of the promoter metal and a metallocene complex of the active phase metal.
The preparation method according to claim 5, wherein the precursor of the active phase metal is selected from any one of the following:

Ferric nitrate, ferric chloride, ferrous chloride, ferrous sulfate, ferrous acetate, iron (III) acetylacetonate, carbonyl iron, ferrocene, cobalt nitrate, cobalt chloride, cobalt formate, cobalt acetate, cobalt acetylacetonate , cobalt carbonyl, tris(ethylenediamine) cobalt chloride (III) trihydrate, nickel nitrate, nickel chloride, nickel sulfate, nickel acetate, nickel acetylacetonate, nickel carbonyl, ruthenium chloride, ruthenium nitrate, triphenyl Phosphonium carbonyl ruthenium, ruthenium carbonyl chloride, ammonium ruthenate and nitrosyl nitrate;

The precursor of the promoter metal is selected from any one of the following:

Manganese nitrate, manganese chloride, manganese acetate, manganese acetylacetonate, manganese carbonyl, zinc nitrate, zinc chloride, zinc sulfate, zinc acetate, zinc acetylacetonate, chromium nitrate, chromium chloride, chromium sulfate, ammonium molybdate, chlorination Platinum, platinum nitrate, chloroplatinic acid, ammonium chloroplatinate, nitrosium diammonium platinum, cerium nitrate, cerium chloride, cerium sulfate, cerium acetate, triphenylphosphine cerium chloride, acetylacetone triphenylphosphine carbonyl Bismuth, palladium nitrate, palladium chloride, palladium sulfate, palladium acetate, ammonium tetrachloropalladate, ammonium hexachloropalladate, triphenylphosphine palladium, chloroantimonic acid, cesium chloride, cesium acetate, ammonium chloroantimonate, chlorine Gold, chloroauric acid, ammonium chloroaurate, silver nitrate, silver acetate, silver carbonate, magnesium nitrate, magnesium chloride, magnesium acetate, calcium nitrate, calcium chloride, calcium acetate, barium nitrate, barium chloride, barium acetate, nitric acid Sodium, sodium chloride, sodium acetate, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, potassium nitrate, potassium chloride, potassium hydroxide, potassium carbonate, potassium hydrogencarbonate and potassium acetate.
The preparation method according to any one of claims 4-6, wherein the carbon-containing atmosphere is a mixed gas of a carbon-containing gas and an inert gas;

The carbon-containing gas is methane, ethane, ethylene, acetylene, propane, propylene, CO, and/or syngas;

In the carbon-containing atmosphere, the volume concentration of the carbon-containing gas is 0.5 to 100%;

The inert gas is selected from at least one of nitrogen, helium, argon, helium and neon;

The carbonization temperature is 350 to 1100 ° C and the time is 1 to 10 hours.
The production method according to any one of claims 4 to 7, characterized in that the calcination temperature is from 300 to 500 ° C for a period of from 1 to 10 hours.
Use of a Fischer-Tropsch synthesis catalyst according to any one of claims 1 to 3 for the synthesis of a hydrocarbon compound in a synthesis gas in a Fischer-Tropsch synthesis reaction.
The use according to claim 9, characterized in that the Fischer-Tropsch synthesis catalyst is reduced in a reducing atmosphere prior to catalyzing the Fischer-Tropsch synthesis reaction.