CN107537500B - Nickel-based Fischer-Tropsch catalyst and using method thereof - Google Patents

Abstract

The invention relates to a nickel-based Fischer-Tropsch catalyst, a preparation method and an application method thereof, which mainly solve the problems of low activity and low selectivity of a catalyst in the preparation of olefin from synthesis gas at low temperature. (1) 20-80% of Ni-containing active component; (2) 20-80% of nano-fiber SiO₂The technical scheme of the carrier well solves the problem and can be used for industrial application of preparing low-carbon olefin from synthesis gas.

Description

Nickel-based Fischer-Tropsch catalyst and using method thereof

Technical Field

The invention relates to a nickel-based Fischer-Tropsch catalyst and a use 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. The Fischer-Tropsch catalyst which is commonly used at present,there are two broad categories of active ingredients: 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.

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. The invention provides a hydrothermal synthesis method which is simple in preparation process, low in consumption and easy to amplify.

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. 1923 German scientists Franz Fisher and Hans Tropsh discovered catalytic conversion of syngas to hydrocarbonsThus, the process for the preparation of hydrocarbons by reaction of synthesis gas is known as the Fischer-Tropsch synthesis (Fischer-Tropsch synthesis, abbreviated to F-T synthesis), i.e. with 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. Today, the annual coal handling capacity of SASOL has reached 5000 ten thousand and the annual production of oils and chemicals has reached 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.

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 nickel-based Fischer-Tropsch catalyst comprises the following components in percentage by weight:

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

(2) 20-80% of nano-fiber SiO₂And (3) a carrier.

In the above technical solution, preferably, the nanofiber SiO₂The diameter of the carrier is 10-500 nanometers; more preferably, the nanofiber SiO₂The diameter of the carrier is 20-200 nm.

In the above technical solution, preferably, the nanofiber SiO₂The preparation method of the carrier comprises the following steps: at least one metal or oxide of iron, cobalt, nickel and zinc is used as a catalyst I, and in the presence of organic amine and water, silicon oxide is subjected to hydrothermal conversion, drying and roasting to obtain the nano-fiber silicon oxide.

In the above embodiment, the silica is preferably at least one selected from silica sol, amorphous silica and crystalline silica.

In the technical scheme, the preferable weight percentage of the catalyst I in the silicon oxide is 0.5-30%; the weight percentage of the catalyst I in the silicon oxide 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 above technical solution, preferably, the Ni-containing active component may be represented by the following general formula in terms of atomic ratio: ni₁₀₀A_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 Ni 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) SiO nano-fiber₂Adding a carrier into the mixture I to obtain 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 nano-fiber SiO₂The carrier has an open void structure, so that the low-carbon olefin product can be rapidly diffused out of catalyst particles, secondary reaction of the low-carbon olefin can be greatly reduced, and the nano-fiber SiO₂The one-dimensional nanometer characteristic of the carrier can promote the dispersion of the active components and make the product move towards the direction of low carbon. By adding various effective auxiliary agents, the adsorption and activation of carbon monoxide and hydrogen are enhanced, the reduction of Ni 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.

Drawings

FIG. 1 is an SEM image of a nanofiber silica.

Detailed Description

[ example 1 ]

Weighing 150 g of methylamine, 350 g of propylamine and 1000 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 500 g of silicon oxide 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 nano-fiber silicon oxide, wherein an SEM spectrogram of the nano-fiber silicon oxide is shown in figure 1.

[ example 2 ]

2000 g of ethylenediamine and 1000 g of deionized water are weighed, mixed into a solution, added into a reaction kettle, 100 g of silicon oxide containing 15% of ferric oxide is weighed, added into the reaction kettle, sealed and heated to 170 ℃, cooled to room temperature after 12 hours of reaction, filtered, dried at 80 ℃ for 24 hours, and roasted at 500 ℃ for 8 hours to obtain the silicon oxide fiber.

[ example 3 ]

Weighing 300 g of ethylamine, 770 g of butylamine, 1700 g of triethylamine and 230 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 60 g of silicon oxide containing 0.6% of ferric oxide and 2.4% of zinc 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 to obtain the silicon oxide fiber.

[ example 4 ]

Dissolving 116.8 g of nickel nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, and dissolving 70 g of the nanofiber SiO prepared in example 1₂Adding the solution I and adjusting the pH value to 8 by using ammonia water to obtainAnd (2) 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% Ni₁₀₀Ox + 70% nanofiber 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.

[ example 5 ]

Dissolving 52.1 g of nickel nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, dissolving 18.2 g of ammonium tungstate in 100 ml of water to obtain solution II, adding the solution II into the solution I to obtain mixture I, and dissolving 70 g of the nano-fiber SiO prepared in example 1 into the mixture I₂Adding 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 ℃ 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: 70% Ni₁₀₀W₄₀Ox + 30% nanofiber 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.

[ example 6 ]

63.3 g of nickel nitrate hexahydrate and 62.3 g of 50% manganese nitrate are dissolved in 100 ml of water to prepare solution I with a certain concentration, and 70 g of nano-fiber SiO prepared in example 1 is added₂Adding 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 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% Ni₁₀₀Mn₈₀Ox + 70% nanofiber SiO₂. Catalyst crushing sieveSelecting 20-40 mesh granules 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 ]

58.2 g of nickel nitrate hexahydrate are dissolved in 100 ml of water to prepare a solution I with a certain concentration, 10.1 g of ammonium tungstate and 7.1 g of ammonium molybdate are dissolved in 100 ml of water to obtain a solution II, the solution II is added into the solution I to obtain a mixture I, and 70 g of the nano-fiber SiO prepared in example 1 is added into the mixture I₂Adding 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 ℃ 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% Ni₁₀₀W₂₀Mo₂₀Ox + 70% nanofiber 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.

[ example 8 ]

Dissolving 43.1 g of nickel nitrate hexahydrate and 2.9 g of copper nitrate trihydrate into 100 ml of water to prepare a solution I with a certain concentration, dissolving 15 g of ammonium tungstate and 5.2 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, and dissolving 70 g of the nano-fiber SiO prepared in example 1 into 70 g of the solution I₂Adding 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 ℃ 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% Ni₁₀₀Cu₈W₄₀Mo₂₀Ox + 70% nanofiber 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^-1Strip ofThe evaluation results are shown in Table 1.

[ example 9 ]

Dissolving 109.7 g of nickel nitrate hexahydrate, 27 g of 50% manganese nitrate and 7.3 g of copper nitrate trihydrate in 100 ml of water to prepare a solution I with a certain concentration, dissolving 53.3 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, and mixing 20 g of the nano-fiber SiO prepared in example 1₂Adding 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 ℃ 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% Ni₁₀₀Cu₈Mn₂₀Mo₈₀Ox + 20% nanofiber 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.

[ example 10 ]

59.2 g of nickel nitrate hexahydrate, 109.4 g of 50% manganese nitrate, 0.4 g of potassium nitrate and 24.6 g of copper nitrate trihydrate are dissolved in 100 ml of water to prepare a solution I with a certain concentration, 2.6 g of ammonium tungstate is dissolved in 100 ml of water to obtain a solution II, the solution II is added into the solution I to obtain a mixture I, and 50 g of the nanofiber SiO prepared in example 1 is added₂Adding 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 ℃ 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: 50% Ni₁₀₀Cu₅₀Mn₁₅₀W₅K₂Ox + 50% nanofiber 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.

[ example 11 ]

Dissolving 12.6 g of nickel 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 16.4 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, and dissolving 80 g of the nano-fiber SiO prepared in example 1₂Adding 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 ℃ 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: 20% Ni₁₀₀W₁₅₀Cu₅₀O_x+ 80% nanofiber 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.

[ example 12 ]

93.6 g of nickel nitrate hexahydrate and 196 g of 50% manganese nitrate are dissolved in 100 ml of water to prepare a solution I with a certain concentration, 6.9 g of ammonium tungstate is dissolved in 100 ml of water to obtain a solution II, the solution II is added into the solution I to obtain a mixture I, and 30 g of the nano-fiber SiO prepared in example 1 is added into the mixture I₂Adding 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 ℃ 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: 70% Ni₁₀₀W₁₀Mn₂₀₀O_x+ 30% nanofiber 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 1

Dissolving 116.8 g of nickel nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, and dissolving 70 g of 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% Ni₁₀₀Ox+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 116.8 g of nickel nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, and dissolving 70 g of 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% Ni₁₀₀Ox+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 150 g of methylamine, 350 g of propylamine and 1000 g of deionized water, mixing to obtain a solution, adding the solution into a reaction kettle, weighing 500 g of silicon oxide containing 0.5% of copper 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 treated silicon oxide (SiO)₂-treated)。

Dissolving 116.8 g of nickel nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, and dissolving 70 g of SiO₂-treating the solution I with ammonia to pH 8 to obtain a mixture II, heating and concentrating the mixture II in a boiling water bath to 55% by weight of solid content to obtain a slurry, and subjecting the slurry to a temperature of 90 ℃ at a relative humidity ofDrying 90% of hot air for 5 hours 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% Ni₁₀₀Ox+70％SiO₂-drilled. 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 116.8 g of nickel nitrate hexahydrate in 100 ml of water to prepare solution I with a certain concentration, and dissolving 70 g of Nano silicon oxide (Nano-SiO)₂) Adding 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% Ni₁₀₀Ox+70％Nano-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.

[ 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 (8)

1. A nickel-based Fischer-Tropsch catalyst comprises the following components in percentage by weight:

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

(2) 20-80% of nano-fiber SiO₂A carrier;

wherein the Ni-containing active component can be represented by the following general formula in terms of atomic ratio: ni₁₀₀A_aB_bO_x

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

b is W and Mo;

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

the value range of b is as follows: 5-50;

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

the ratio of W to Mo is 1-2;

the nano-fiber SiO₂The preparation method of the carrier comprises the following steps: SiO using at least one metal or oxide of iron, cobalt, nickel and zinc as catalyst I₂Is SiO₂A carrier, SiO in the presence of an organic amine and water₂The carrier is subjected to hydrothermal conversion, drying and roasting to prepare the nano-fiber SiO₂And (3) a carrier.

2. The nickel-based Fischer-Tropsch catalyst of claim 1, wherein the nanofibers comprise SiO₂The diameter of the carrier is 10-500 nm.

3. The nickel-based Fischer-Tropsch catalyst of claim 1, wherein the nanofibers comprise SiO₂The diameter of the carrier is 20-200 nm.

4. The nickel-based Fischer-Tropsch catalyst of claim 1, wherein the silica comprises from about 0.5 to about 30 wt% of catalyst I.

5. Nickel-based fischer-tropsch catalyst according to claim 1, wherein the weight ratio of organic amine to water is (0.5-20): 1.

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

7. The nickel-based Fischer-Tropsch catalyst of claim 1, wherein the hydrothermal conversion time is in the range of from 12 to 96 hours.

8. 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 (1), the synthesis gas contacts and reacts with the catalyst of any one of claims 1 to 7 to generate the low-carbon olefin.

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