CN107537586B - Porous ceramic supported iron-based Fischer-Tropsch catalyst and use method thereof - Google Patents

Abstract

The invention relates to a porous ceramic supported iron-based Fischer-Tropsch catalyst, a preparation method and a use method thereof, which mainly solve the problems of low activity and low selectivity of a catalyst in preparation of olefin from synthesis gas at low temperature, and the invention adopts the catalyst for preparing low-carbon olefin from synthesis gas, and comprises the following components in percentage by weight: (1) 20-80% of active component containing Fe; (2) the technical scheme of 20-80% of the large-surface porous ceramic carrier well solves the problem and can be used for industrial application of preparing low-carbon olefin from synthesis gas.

Description

Porous ceramic supported iron-based Fischer-Tropsch catalyst and use method thereof

Technical Field

The invention relates to a porous ceramic supported iron-based Fischer-Tropsch catalyst and a using method thereof.

Background

The low-carbon olefins (olefins with carbon atoms less than or equal to 4) represented by ethylene and propylene are basic raw materials in chemical industry, at present, the main raw materials of the low-carbon olefins in the world are petroleum hydrocarbons, wherein naphtha accounts for the majority, and alkane, hydrogenated diesel oil, part of heavy oil and the like are also used. Natural gas or light petroleum fractions are mostly used as raw materials at home and abroad, and low-carbon olefin is produced by adopting a steam cracking process in an ethylene combined device. Steam cracking is a large energy consuming device in petrochemical industry and is completely dependent on non-renewable petroleum resources. With the increasing shortage of petroleum resources, alternative resources are urgently needed to be searched. Therefore, the research work of producing olefin by replacing petroleum with natural gas is regarded as important, and some famous petroleum companies and scientific research institutes in the world carry out the research and development work and obtain the attractive results. Under the background of adjusting the structure of energy utilization at present to gradually reduce the dependence of national economic development on petroleum energy, natural gas resources rich in reserves in China are utilized to prepare synthesis gas (carbon monoxide and hydrogen mixed gas) through gas making, and then the synthesis gas is converted into C2-C4 olefin, so that the method has high strategic significance in the long run.

The method for converting the synthesis gas into the olefin comprises an indirect method and a direct method, wherein a process for preparing the low-carbon olefin MTO by cracking the methanol and a process for preparing the low-carbon olefin SDTO by the dimethyl ether from the formed gas comprise the steps of firstly synthesizing the methanol or the dimethyl ether from the synthesis gas and then converting the methanol or the dimethyl ether into the olefin.

Fischer-Tropsch synthesis uses synthesis gas (with the major components being CO and H)₂) The process of synthesizing hydrocarbon under the action of catalyst is an important way for indirect liquefaction of coal and natural gas. The method is invented in 1923 by German scientists Frans Fischer and Hans Tropsh, namely a process of carrying out heterogeneous catalytic hydrogenation reaction on CO on a metal catalyst to generate a mixture mainly comprising straight-chain alkane and olefin. Research and development are carried out in the last 20 th century in germany, and industrialization is realized in 1936, and the two-war aftermath is closed because the economy cannot compete with the petroleum industry; south Africa has abundant coal resources, but oil resources are scarce, and are limited by international socioeconomic and political sanctions for a long time, so that the south Africa is forced to develop the coal-to-oil industrial technology, and a first coal-based F-T synthetic oil plant (Sasol-1) with the production capacity of 25-40 ten thousand tons of products per year is built in 1955. The two global oil crises in 1973 and 1979 caused the price of crude oil in the world to fall and rise greatly, and the F-T synthesis technology re-aroused interest in industrialized countries based on the consideration of strategic technical reserves. In 1980 and 1982, Sasol company in south Africa built and produced two coal-based synthetic oil plants in succession. However, the great reduction of the oil price in the world in 1986 postpones the large-scale industrialization process of the F-T synthesis technology in other countries.Since the 90 s of the twentieth century, petroleum resources are in shortage and deterioration, and the exploratory reserves of coal and natural gas are increasing, the fischer-tropsch technology attracts extensive attention again, and the fischer-tropsch synthesis technology is developed greatly. Currently, the fischer-tropsch catalysts commonly used are divided into two main groups in terms of active components: an iron-based catalyst and a cobalt-based catalyst; while the common synthetic processes are classified into two main categories from the viewpoint of synthetic conditions: a high temperature Fischer-Tropsch synthesis process and a low temperature Fischer-Tropsch synthesis process; the synthesis processes are classified into three main groups, depending on the reactor used: fixed bed fischer-tropsch synthesis processes, fluidised bed fischer-tropsch synthesis processes (with an earlier circulating fluidised bed and a later fixed fluidised bed developed on the basis of a circulating fluidised bed) and slurry bed fischer-tropsch synthesis processes. The fixed bed and the slurry bed are generally applied to a low-temperature Fischer-Tropsch process and are mainly used for producing heavy oil and wax, and the fluidized bed is more suitable for a high-temperature Fischer-Tropsch process for producing lighter hydrocarbons.

The purpose of the present carbon-chemical synthesis of hydrocarbons is to convert them into lower olefins as basic chemical raw materials, of which ethylene and propylene are currently the most valuable materials. Moreover, the synthesis gas is directly used for preparing the low-carbon olefin to be a target product generated by one-step reaction, the process flow is simpler than that of an indirect method, and the economic evaluation is more economical. In the last decade, direct synthesis of lower olefins from synthesis gas has become a concern.

The synthesis gas is directly converted into the low-carbon olefin through Fischer-Tropsch synthesis, and besides the influence of reaction process conditions, thermodynamics and kinetics, the catalyst is one of the most important influencing factors. Franz Fisher and Hans Tropsch, German scientists, in 1923, discovered reactions for the catalytic conversion of synthesis gas to hydrocarbons, and the process for the preparation of hydrocarbons from synthesis gas reactions was therefore known as the Fischer-Tropsch (F-T) synthesis process, i.e., the synthesis of hydrocarbons from CO and H₂Reaction for producing hydrocarbons, by-product water and CO₂. In 1955, a large fixed bed F-T synthesis plant using Coal as raw material was built by SASOL (south Africa Coal and Gas corporation), followed by the development of circulating fluidized bed technology, and recently, fixed fluidized bed and slurry bed technology. Coal of SASOL todayThe annual processing capacity reaches 5000 ten thousand, and the annual capacity of oil products and chemicals reaches 760 ten thousand tons. Although the conventional Fischer-Tropsch synthesis reaction aims at synthesizing liquid hydrocarbons for fuel from synthesis gas, the yield of low-carbon olefins (C2-C4 olefins) is improved to a certain extent by using a fluidized bed technology, an iron-based catalyst and adding auxiliaries, but the yield of the low-carbon olefins is still not high and is only 20-25%.

At present, the catalytic systems for preparing low-carbon olefins from synthesis gas mainly comprise the following systems. (1) The modified F-T catalyst Dent et al found that the cobalt-based catalyst can be used for synthesizing low-carbon olefins with high selectivity, such as: Co-Cu/Al₂O₃、Co-Fe/SiO₂、Fe-Co/C、Co-Ni/MnO₂And Fe-Co alloy systems. Among these, the improved FT catalyst developed by the luer chemical company gave better results in Fe-ZnO-K₂Mn or Ti and other components are added on the O catalyst, and high-speed gas circulation is adopted, so that the conversion rate of CO is 80%, and the selectivity of low-carbon olefin is 70%; (2) the superfine particle catalyst Venter and the like obtain the activated carbon supported high-dispersion K-Fe-Mn catalyst by a carbonyl complex decomposition method, the catalyst has high activity, and C in the product₂-C₄Olefins account for 85-90% and methane is the only other product detected. Cupta et al, using laser pyrolysis, produce catalytically active Fe_xSi_yC_zEqual powder CO conversion of 40%, C₂ ^＝-C₄ ^＝The selectivity reaches 87%, and only a small amount of methane is needed. Shanxi coal chemical industry cloguan, etc. successfully develops and develops a novel and practical ultrafine particle Fe/Mn catalyst by adopting a degradation method of an organic salt compound, the CO conversion rate is more than 95 percent, and C is₂ ^＝-C₄ ^＝/C₂-C₄Greater than 80%. The highly dispersed amorphous superfine iron powder and carbon powder are prepared by laser pyrolysis method and are successfully prepared into a new F-T synthetic active species Fe through solid-phase reaction₃C. Preparation of Fe₃The C is a main body of Fe-C, Fe-C-Mn, Fe-C-Mn-K and other nano catalysts, the CO conversion rate reaches 90 percent, and the olefin selectivity reaches more than 80 percent; (3) amorphous synthetic catalyst Yokoyama et al uses amorphous Fe₄₀Ni₄₀P₁₆B₄Compound, CO conversion 50%, C₂-C₅The hydrocarbon selectivity was 65%, while the crystalline catalyst produced predominantly methane; (4) the zeolite catalyst is represented by Co-A, Co-Y, Fe-Y and other catalysts, the high-dispersion iron catalyst carried by the zeolite prepared by Ballvet-Tketchenko et al has quite high selectivity of low-carbon olefin, and 88-98 percent of the low-carbon olefin is in C₂-C₄Other iron catalysts such as ZSM-5, mordenite, zeolite 13X supported iron catalysts also showed similar behavior in the range. However, these catalysts have encountered varying degrees of difficulty in the procedures of preparation repeatability, scale-up of preparation, etc.

A nanowire is a line of nanometre dimensions, i.e. a one-dimensional structure confined in the lateral direction to nanometre dimensions. On this scale, quantum mechanical effects are important and are therefore also referred to as "quantum wires". Depending on the material composition, nanowires can be classified into different types, including metal nanowires (e.g., Ni, Pt, Au, etc.), semiconductor nanowires (e.g., InP, Si, GaN, etc.), insulator nanowires (e.g., SiO2, TiO2, etc.), and other biomass nanowires. (Yi Cui, Qingqi Wei, Hongkunpark, Charles M.

Science, 2001,293 (5533): 1289) the nano wire has an oversized surface and high toughness, and has the characteristics of large catalytic contact surface, better wear resistance and the like when being applied to catalytic reaction.

The one-dimensional silicon oxide nano fiber has the characteristics of high insulating property, good fluorescence effect, high surface area, surface activity and the like, has great application potential in the fields of micro-nano device assembly, nano array research, nano optical transmission, nano high insulation resistance and the like, and simultaneously has wide prospect in the fields of traditional industrial catalysis, high polymer material reinforcement, cosmetic whitening, ultraviolet resistance and the like as a novel nano material. Therefore, research on the synthesis method of the one-dimensional silicon oxide nanowire is a research hotspot in the field of materials in recent years.

At present, the preparation Method of the one-dimensional nano silicon oxide fiber mainly comprises a physical Method and a chemical Method, and the physical Method is mainly a Laser Ablation Method (D.P.Yu, Q.L.Handg, Y.Ding, appl.Phys.Lett.,1998,73: 3076). The laser ablation method is to mix silicon, silicon oxide and iron catalyst in a certain proportion to prepare a target, and then to grow silicon oxide nano-wires by laser etching at high temperature. The method has high temperature and harsh conditions, and is not suitable for large-scale industrial production. The chemical method mainly comprises the following steps: high-temperature chemical sedimentation method, sol-gel method and auxiliary agent assisted growth method. The chemical immersion method is widely used for preparing carbon nanotubes, and adopts a gas mixed silicon source to be mixed with a metal catalyst at a high temperature, and then the mixture is cooled and condensed to generate nanowires under the action of the metal catalyst. The assistant growth method is to generate the nano-wire under the condition of the existence of the assistant growth agent. For example, high temperature synthesis of nano-silica wires in the presence of carbon (s. -h.li, x. -f.zhu, y. -p.zhao, j.phys.chem.b, 2004, 108: 17032); CN101798089A adopts germanium as a catalyst, and prepares the silicon oxide nanowire under the conditions of ultrahigh vacuum and high temperature, which are harsh and difficult to amplify. The sol-gel method adopts a template agent to form a nano-pore channel, and the nano-pore channel is used as the template to synthesize the silicon oxide nanowire, and the sol-gel method needs to consume a large amount of the template agent, has high cost and is not environment-friendly.

Industrial catalysts are required to have a certain physical shape and porosity to meet the operational requirements and mass and heat transfer efficiency requirements of industrial reactors. Although the one-dimensional silica nanofibers perform well, the radial dimension is on the nanometer scale due to the small size, while the size of the general industrial heterogeneous catalyst is on the millimeter scale, and even the size of the differential catalyst used in the slurry bed and the fluidized bed is on the micrometer scale. Therefore, the one-dimensional nanofiber silica is not suitable for being directly used as a catalyst carrier, and can cause catalyst loss and bed plugging. Therefore, secondary molding is necessary to meet industrial requirements. However, secondary molding can cause fiber breakage, pulverization and substantial reduction of rich stacking voids, so that the nano fibrous silica loses many advantages as a catalyst carrier and has an influence on efficient mass and heat transfer capacity.

The porous ceramic material is prepared by taking high-quality raw materials such as corundum, silicon carbide, cordierite and the like as main materials through molding and a special high-temperature sintering process, has the advantages of high temperature resistance, high pressure resistance, acid corrosion resistance, alkali corrosion resistance and organic medium corrosion resistance, good biological inertia, controllable pore structure, high open porosity, long service life, good product regeneration performance and the like. However, porous ceramics have a small specific surface area due to their large pore size. When used as a catalyst carrier, the catalyst has excellent mass and heat transfer efficiency, but the catalyst activity is low because of low dispersion of the catalyst active components.

The invention provides a preforming-hydrothermal synthesis method, which is characterized in that porous ceramics are prepared into granularity and shape meeting industrial requirements through preforming, and silicon dioxide on the surface of the ceramics is converted into nano fibrous silicon dioxide through hydrothermal synthesis on the basis of keeping the original shape, so that the porous ceramics not only has excellent mass transfer and heat transfer efficiency, high strength and corrosion resistance of the porous ceramics, but also has larger specific surface area, simple preparation process, less consumption and easy amplification, and is used as a carrier of a catalyst for preparing low-carbon olefin from synthesis gas, and the catalyst has good mass transfer and heat transfer performance and high activity and selectivity.

Disclosure of Invention

One of the technical problems solved by the invention is the problem that the catalyst for preparing low-carbon olefin (C2-C4 olefin) from synthesis gas in the prior art has low activity and selectivity at low temperature, and the catalyst for preparing low-carbon olefin from synthesis gas is provided and has better low-temperature activity and low-carbon olefin selectivity. The second technical problem to be solved by the present invention is to provide a method for preparing a catalyst corresponding to the first technical problem.

In order to solve one of the above technical problems, the technical scheme adopted by the invention is as follows: a porous ceramic supported iron-based Fischer-Tropsch catalyst comprises the following components in percentage by weight:

(1) 20-80% of active component containing Fe;

(2) 20-80% of a large-surface porous ceramic carrier.

In the technical scheme, preferably, the weight content of the silica of the large-surface porous ceramic carrier is 5-50%; more preferably, the large surface porous ceramic support has a porosity greater than 20%.

In the above technical solution, preferably, the specific surface area of the large-surface porous ceramic carrier is greater than 5m²/g。

In the above technical solution, more preferably, the specific surface area of the large-surface porous ceramic support is greater than 10m²/g。

In the above technical solution, preferably, the preparation method of the large-surface porous ceramic carrier includes the following steps: at least one metal or oxide of iron, cobalt, nickel and zinc is used as a catalyst I, and the porous ceramic is subjected to hydrothermal conversion, drying and roasting in the presence of organic amine and water to obtain the large-surface porous ceramic.

In the technical scheme, preferably, the weight percentage of the catalyst I in the porous ceramic is 0.5-30%; more preferably, the weight percentage of the catalyst I in the porous ceramic is 0.5-5%.

In the above technical solution, preferably, the weight ratio of the organic amine to the water is (0.5-20): 1.

in the above technical solution, the hydrothermal conversion temperature is preferably 150-.

In the above technical scheme, preferably, the hydrothermal conversion time is 12 to 96 hours; more preferably, the hydrothermal conversion time is from 48 to 72 hours.

In the technical scheme, the porous ceramic is preferably silicon-aluminum ceramic, and the specific surface area is generally less than 1m²/g。

In the above technical solution, preferably, the Fe-containing active component may be represented by the following general formula in terms of atomic ratio: fe₁₀₀A_aB_bO_x

Wherein A is at least one selected from Mn or Cu;

b is at least one selected from W or Mo;

the value range of a is as follows: 0 to 200 parts by weight;

the value range of b is as follows: 0 to 150 parts by weight;

x is the total number of oxygen atoms required to satisfy the valences of the other elements.

In the above technical scheme, preferably, the value range of a is 5-150; more preferably, the value range of a is 20-150.

In the above technical scheme, preferably, the value range of b is 5-50; preferably, B is selected from W and Mo; more preferably, the ratio of W to Mo is 1 to 2.

To solve the second technical problem, the invention adopts the following technical scheme: the preparation method of the catalyst comprises the following steps:

(1) dissolving soluble salt containing components Fe and A in deionized water to prepare solution I;

(2) dissolving soluble salt containing the component B in deionized water to prepare solution II;

(3) adding the solution II into the solution I to form a mixture I;

(4) adding the large-surface porous ceramic carrier into the mixture I to prepare a mixture II;

(5) adjusting the pH value of the mixture II to 8-10 by using alkali, and heating and concentrating to obtain slurry;

(6) drying the slurry to obtain a catalyst precursor;

(7) the catalyst precursor is roasted to prepare the catalyst.

In the above technical scheme, preferably, the solid content of the slurry obtained after the concentration in the step (5) is 60-80 wt%; the drying temperature in the step (6) is 70-90 ℃, and the drying time is 5-40 hours; the roasting temperature in the step (7) is 500-800 ℃, and the roasting time is 2-12 hours.

The use method of the catalyst is as follows: a method for preparing low-carbon olefin from synthesis gas comprises the steps of reacting at 220-280 ℃ under a reaction pressure of 0.5-2.5MPa and at a volume space velocity of 1000-^-1Under the condition of (1), the synthesis gas contacts and reacts with the catalyst to generate the low-carbon olefin.

The invention adopts the large-surface porous ceramic as the carrier, has an open gap structure, can enable the low-carbon olefin product to quickly diffuse out of catalyst particles, can greatly reduce the secondary reaction of the low-carbon olefin, and can promote the dispersion of active components and enable the product to move towards the low-carbon direction due to the high specific surface area of the surface of the large-surface porous ceramic carrier. By adding various effective auxiliary agents, the adsorption and activation of carbon monoxide and hydrogen are enhanced, the reduction of iron is promoted, higher activity and low-carbon olefin selectivity can be kept at lower reaction temperature, and the problem of carbon deposition during reaction at high temperature can be avoided. Particularly, when the VIA group oxide is added into the catalyst, the dispersion of the active component oxide can be promoted, and the active component can be better fixed in the reduction process of the catalyst so as to keep good dispersion.

The catalyst prepared by the method has the advantages of 350 ℃ at 250-^-1Under the conditions of (1), CO conversion>80％，C₂-C₄Olefin selectivity>55%, and a better technical effect is achieved.

The invention is further illustrated by the following examples.

Detailed Description

[ example 1 ]

Weighing 30 g of methylamine, 70 g of propylamine and 200 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 100 g of porous ceramic containing 0.25% of ferric oxide and 0.25% of zinc oxide, adding the solution into the reaction kettle, sealing and heating to 160 ℃, reacting for 24 hours, cooling to room temperature, filtering solids, drying at 100 ℃ for 5 hours, and roasting at 400 ℃ for 12 hours.

[ example 2 ]

Weighing 200 g of ethylenediamine and 100 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 10 g of porous ceramic containing 15% of iron oxide, adding the solution into the reaction kettle, sealing, heating to 170 ℃, reacting for 12 hours, cooling to room temperature, filtering solids, drying at 80 ℃ for 24 hours, and roasting at 500 ℃ for 8 hours.

[ example 3 ]

Weighing 30 g of ethylamine, 77 g of butylamine, 170 g of triethylamine and 23 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 6 g of porous ceramic containing 0.6% of cobalt oxide and 2.4% of nickel oxide, adding the solution into the reaction kettle, sealing, heating to 250 ℃, reacting for 72 hours, cooling to room temperature, filtering solids, drying at 120 ℃ for 2 hours, and roasting at 800 ℃ for 1 hour.

[ example 4 ]

Dissolving 131.5 g of ferric nitrate hexahydrate in 100 ml of water to prepare a solution I with a certain concentration, adding 70 g of the large-surface porous ceramic prepared in the example 1 into the solution I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 90 ℃ for 5 hours by using hot air with the relative humidity of 90% to obtain a catalyst precursor, and roasting the catalyst precursor at 650 ℃ for 5 hours to obtain the catalyst, wherein the catalyst comprises the following components: 30% Fe₁₀₀Ox + 70% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ example 5 ]

Dissolving 60.8 g of ferric nitrate hexahydrate in 100 ml of water to prepare a solution I with a certain concentration, dissolving 17.6 g of ammonium tungstate in 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 70 g of the large-surface porous ceramic prepared in the example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II to 55 wt% of solid content to obtain slurry, drying the slurry at 80 ℃ by using hot air with the relative humidity of 90% for 12 hours to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the catalyst comprises the following components: 70% Fe₁₀₀W₄₀Ox + 30% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ example 6 ]

Dissolving 73.4 g of ferric nitrate hexahydrate and 60.1 g of 50% manganese nitrate in 100 ml of water to prepare a solution I with a certain concentration, adding 70 g of the large-surface porous ceramic prepared in example 1 into the solution I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II to obtain a slurry with the solid content of 55% by weight, and drying the slurry at 80 ℃ for 12 hours by using hot air with the relative humidity of 90% to obtain a catalystThe catalyst precursor is roasted for 3 hours at 750 ℃ to prepare the catalyst, and the catalyst comprises the following components: 30% Fe₁₀₀Mn₈₀Ox + 70% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ example 7 ]

Dissolving 67.7 g of ferric nitrate hexahydrate in 100 ml of water to prepare a solution I with a certain concentration, dissolving 9.8 g of ammonium tungstate and 6.8 g of ammonium molybdate in 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 70 g of the large-surface porous ceramic prepared in the example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 80 ℃ by using hot air with the relative humidity of 90% for 12 hours to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the catalyst comprises the following components: 30% Fe₁₀₀W₂₀Mo₂₀Ox + 70% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ example 8 ]

Dissolving 50.6 g of ferric nitrate hexahydrate and 2.8 g of cupric nitrate trihydrate into 100 ml of water to prepare a solution I with a certain concentration, dissolving 14.6 g of ammonium tungstate and 5.1 g of ammonium molybdate into 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 70 g of the large-surface porous ceramic prepared in the example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II into a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 80 ℃ for 12 hours by using hot air with the relative humidity of 90% to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the catalyst comprises the following components: 30% Fe₁₀₀Cu₈W₄₀Mo₂₀Ox + 70% large surface porous ceramic. Catalyst comminutionScreening 20-40 mesh particles for later use.

The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ example 9 ]

Dissolving 128.9 g of ferric nitrate hexahydrate, 26.4 g of 50% manganese nitrate and 7.1 g of cupric nitrate trihydrate in 100 ml of water to prepare a solution I with a certain concentration, dissolving 52 g of ammonium molybdate in 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 20 g of the large-surface porous ceramic prepared in the example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55% by weight to obtain slurry, drying the slurry at 80 ℃ for 12 hours by using hot air with the relative humidity of 90% to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the catalyst comprises the following components: 80% Fe₁₀₀Cu₈Mn₂₀Mo₈₀Ox + 20% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ example 10 ]

Dissolving 69.8 g of ferric nitrate hexahydrate, 107.2 g of 50% manganese nitrate, 0.4 g of potassium nitrate and 24.1 g of copper nitrate trihydrate into 100 ml of water to prepare a solution I with a certain concentration, dissolving 2.5 g of ammonium tungstate into 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 50 g of the large-surface porous ceramic prepared in example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II into a boiling water bath, heating and concentrating the mixture II until the solid content is 55% by weight to obtain slurry, drying the slurry at 80 ℃ by using hot air with the relative humidity of 90% for 12 hours to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the composition of the catalyst precursor is as follows: 50% Fe₁₀₀Cu₅₀Mn₁₅₀W₅K₂Ox + 50% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. Catalyst at reaction temperature250 ℃, the reaction pressure is 1.0Mpa, and the reaction space velocity is 2000h^-1The evaluation results are shown in Table 1.

[ example 11 ]

Dissolving 15 g of ferric nitrate hexahydrate and 5.2 g of copper nitrate trihydrate in 100 ml of water to prepare a solution I with a certain concentration, dissolving 16.3 g of ammonium tungstate in 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 80 g of the large-surface porous ceramic prepared in the example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 80 ℃ by using hot air with the relative humidity of 90% for 12 hours to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the catalyst comprises the following components: 20% Fe₁₀₀W₁₅₀Cu₅₀O_x+ 80% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation conditions and evaluation results are shown in Table 1

[ example 12 ]

Dissolving 93.9 g of ferric nitrate hexahydrate and 192 g of 50% manganese nitrate in 100 ml of water to prepare a solution I with a certain concentration, dissolving 6.8 g of ammonium tungstate in 100 ml of water to obtain a solution II, adding the solution II into the solution I to obtain a mixture I, adding 30 g of the large-surface porous ceramic prepared in the example 1 into the mixture I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55% by weight to obtain slurry, drying the slurry at 80 ℃ by using hot air with the relative humidity of 90% for 12 hours to obtain a catalyst precursor, and roasting the catalyst precursor at 750 ℃ for 3 hours to obtain the catalyst, wherein the catalyst comprises the following components: 70% Fe₁₀₀W₁₀Mn₂₀₀O_x+ 30% large surface porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation conditions and evaluation results are shown in Table 1

Comparative example 1

Dissolving 131.5 g ferric nitrate hexahydrate in 100 ml water to prepare solution I with certain concentration, and dissolving 70 g SiO₂Adding the solution I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 90 ℃ for 5 hours by using hot air with the relative humidity of 90% to obtain a catalyst precursor, and roasting the catalyst precursor at 650 ℃ for 5 hours to obtain the catalyst, wherein the catalyst comprises the following components: 30% Fe₁₀₀Ox+70％SiO₂. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

Comparative example 2

Dissolving 131.5 g ferric nitrate hexahydrate in 100 ml water to prepare solution I with certain concentration, and dissolving 70 g α -Al₂O₃Adding the solution I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 90 ℃ for 5 hours by using hot air with the relative humidity of 90% to obtain a catalyst precursor, and roasting the catalyst precursor at 650 ℃ for 5 hours to obtain the catalyst, wherein the catalyst comprises the following components: 30% Fe₁₀₀Ox+70％α-Al₂O₃. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

Comparative example 3

Weighing 30 g of methylamine, 70 g of propylamine and 200 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 100 g of SiC containing 0.25% of ferric oxide and 0.25% of zinc oxide, adding the solution into the reaction kettle, sealing and heating to 160 ℃, reacting for 24 hours, cooling to room temperature, filtering solids, drying at 100 ℃ for 5 hours, and roasting at 400 ℃ for 12 hours to obtain the treated SiC.

Dissolving 131.5 g of ferric nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, adding 70 g of treated SiC into the solution I, adjusting the pH value to 8 by using ammonia water to obtain mixture II, and placing the mixture II in a boiling water bath for heating and concentrating until the solid content is reached55 wt% to obtain slurry, drying the slurry at 90 deg.C with hot air with relative humidity of 90% for 5 hr to obtain catalyst precursor, and calcining the catalyst precursor at 650 deg.C for 5 hr to obtain the catalyst, which comprises: 30% Fe₁₀₀Ox + 70% SiC. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

Comparative example 4

Dissolving 131.5 g of ferric nitrate hexahydrate in 100 ml of water to prepare a solution I with a certain concentration, adding 70 g of porous ceramic into the solution I, adjusting the pH value to 8 by using ammonia water to obtain a mixture II, placing the mixture II in a boiling water bath, heating and concentrating the mixture II until the solid content is 55 wt% to obtain slurry, drying the slurry at 90 ℃ for 5 hours by using hot air with the relative humidity of 90% to obtain a catalyst precursor, and roasting the catalyst precursor at 650 ℃ for 5 hours to obtain the catalyst, wherein the catalyst comprises the following components: 30% Fe₁₀₀Ox + 70% porous ceramic. The catalyst is crushed and screened into particles of 20-40 meshes for later use. The catalyst is reacted at 250 deg.c and 1.0MPa in the reaction pressure and space velocity of 2000 hr^-1The evaluation results are shown in Table 1.

[ examples 13 to 18 ]

The catalyst prepared in example 4 was used, and the evaluation conditions and the evaluation results are shown in Table 2.

TABLE 1

TABLE 2

Claims (9)

1. A porous ceramic supported iron-based Fischer-Tropsch catalyst comprises the following components in percentage by weight:

(1) 20-80% of active component containing Fe;

(2) 20-80% of a large-surface porous ceramic carrier;

the preparation method of the large-surface porous ceramic carrier comprises the following steps: porous ceramic containing at least one metal or oxide of iron, cobalt, nickel and zinc as a catalyst I is taken as a porous ceramic carrier, and the porous ceramic carrier is subjected to hydrothermal conversion, drying and roasting in the presence of organic amine and water to obtain the large-surface porous ceramic carrier.

2. The porous ceramic supported iron-based fischer-tropsch catalyst of claim 1, wherein the large surface porous ceramic support has a silica content of 5-50% by weight.

3. The porous ceramic supported iron-based fischer-tropsch catalyst of claim 1, wherein the large surface porous ceramic support has a porosity greater than 20%.

4. The porous ceramic supported iron-based Fischer-Tropsch catalyst of claim 1, wherein the porous ceramic has a catalyst I content of 0.5-30% by weight.

5. The porous ceramic supported iron-based fischer-tropsch catalyst of claim 1, wherein the weight ratio of organic amine to water is (0.5-20): 1.

6. the porous ceramic supported iron-based Fischer-Tropsch catalyst of claim 1, wherein the hydrothermal conversion temperature is 150 ℃ and 250 ℃.

7. The porous ceramic supported iron-based Fischer-Tropsch catalyst of claim 1, wherein the hydrothermal conversion time is from 12 to 96 hours.

8. The porous ceramic supported iron-based Fischer-Tropsch catalyst of claim 1, wherein the Fe-containing active component is present in an atomic ratioRepresented by the following general formula: fe₁₀₀A_aB_bO_x

Wherein A is at least one selected from Mn or Cu;

b is at least one selected from W or Mo;

the value range of a is as follows: 0 to 200 parts by weight;

the value range of b is as follows: 0 to 150 parts by weight;

x is the total number of oxygen atoms required to satisfy the valences of the other elements.

9. A method for preparing low-carbon olefin by using synthesis gas, wherein the reaction temperature is 220-280 ℃, the reaction pressure is 0.5-2.5MPa, and the volume space velocity is 1000-4000h^-1Under the condition of (a), the synthesis gas contacts with the catalyst of any one of claims 1 to 8 to react to generate the low-carbon olefin.