A cobalt-based Fischer-Tropsch catalyst and its preparation method and application

Abstract

The present invention discloses a cobalt-based Fischer-Tropsch catalyst and its preparation method and application. The cobalt-based Fischer-Tropsch catalyst comprises a carrier and an active component loaded on the carrier; the carrier is a manganese-modified composite carrier Mn-TiO2 / MgO; the active component has the general formula of Co in terms of atomic ratio: 100 A a B b Wherein, A is selected from at least one of Ru, Pt, and Ir, B is selected from at least one of Zr and Nb, the value range of a is 0 to 5, and the value range of b is 0 to 15. When the cobalt-based Fischer-Tropsch catalyst of the present invention is used in the Fischer-Tropsch synthesis reaction, it can increase the C content in the Fischer-Tropsch product. 5+ The catalyst is highly selective for hydrocarbons, has high activity and low methane selectivity, and is an efficient Fischer-Tropsch synthesis catalyst. The preparation method is simple and the catalyst is easy to use in industry.

Description

Technical Field

[0001] The present invention relates to the field of catalytic synthesis gas conversion, and in particular to a cobalt-based Fischer-Tropsch catalyst and a preparation method and application thereof. Background Art

[0002] Fischer-Tropsch synthesis (FTS) is the conversion of synthesis gas (CO + H2) into long-chain hydrocarbons, typically using a heterogeneous catalytic process. FTS products can be upgraded to produce clean fuels such as light olefins and liquid fuels, or high-value-added chemicals such as lubricants and solid waxes. FTS catalysts primarily include iron- and cobalt-based catalysts. Cobalt-based catalysts offer high activity, stability, conversion rates, and hydrocarbon yields at low temperatures, making them the optimal choice for synthesizing long-chain hydrocarbons.

[0003] The activity and product selectivity of cobalt-based catalysts generally depend on the dispersion and reducibility of the cobalt species, as well as the adsorption characteristics of the reactant gases on the catalyst surface. Cobalt-based catalysts are mostly supported catalysts. The challenge lies in optimally combining the active component, metal promoter, precious metal promoter, and support to prepare high-performance Fischer-Tropsch synthesis catalysts for industrial application. Modifying the catalyst by adding a secondary metal is one effective way to manipulate the catalyst's structure and catalytic performance.

[0004] Dinse et al. (Dinse A, Aigner M, Ulbrich M, et al. Effects of Mn promotion on the activity and selectivity of Co / SiO2 for Fischer–Tropsch Synthesis[J]. Journal of Catalysis, 2012, 288:104-114.) used an equal volume impregnation method to impregnate a silica support with a pore size of 27 nm using a cobalt nitrate solution and a manganese acetate solution. A small amount of Mn was added to the Co / SiO2 catalyst. The study found that at 1 atm (Mn / Co = 0.05), the addition of Mn increased the CO consumption rate and suppressed the formation of CH4. The C 5+ Hydrocarbon selectivity increased, but the selectivity for C2-C4 products was unaffected. Increasing the pressure to 10 atm increased the CO consumption rate for both the unpromoted and Mn-added Co / SiO2 catalysts. However, due to the higher CO suppression, the reaction rate was lower for the Mn-added catalyst. Furthermore, this method only conducted short-term stability assessments, with no long-term evaluation results available, indicating that the catalysts exhibited superior stability.

[0005] Morales et al. (Morales F, Degroot F, Gijzeman O, et al. Mn promotion effects in Co / TiO2 Fischer-Tropsch catalysts as investigated by XPS and STEM-EELS [J]. Journal of Catalysis, 2005, 230(2): 301-308.) modified Co / TiO2 with a small amount of Mn, increasing FTS activity and suppressing CH4 yield. Characterization results showed that the calcined catalysts had significant Co-Mn interactions, which may have promoted the formation of solid solution spinel compounds and increased the difficulty of reducing cobalt species.

[0006] Zhang et al. (Zhang Qingling, Guo Heqin, Bo Hou, et al. Effects of Mn and Zr promoters on the Fischer-Tropsch synthesis performance of mesoporous carbon-supported cobalt-based catalysts [J]. Journal of Fuel Chemistry and Technology, 2017, 45(6): 682-688.) prepared mesoporous carbon-supported cobalt-based catalysts modified by manganese and zirconium by impregnation method. The addition of manganese or zirconium promoters reduced the selectivity of methane. Among them, the addition of manganese promoter increased the selectivity of C 2-4 The addition of zirconium improves the dispersion of cobalt species, increases the reactive sites, and significantly improves the Fischer-Tropsch reaction activity and C 5+ Selectivity. This modification method has made significant progress in improving the activity and product selectivity of cobalt-based Fischer-Tropsch synthesis catalysts. However, it does not address all aspects of performance simultaneously. Most catalysts have a narrow selectivity temperature range and poor adaptability. Furthermore, long-term evaluation results are lacking, indicating that the catalysts have good stability.

[0007] CN107617442A discloses a Fischer-Tropsch synthesis precipitated iron-based catalyst containing a manganese additive, and uses it in a Fischer-Tropsch synthesis slurry bed reactor. It is found that the catalyst can increase the CO conversion rate and reduce the selectivity of methane and carbon dioxide.

[0008] CN113117689A discloses a cobalt-based Fischer-Tropsch synthesis catalyst containing a manganese additive, its preparation method, and its use in the Fischer-Tropsch synthesis reaction. The catalyst uses a cobalt-aluminum spinel support modified by the addition of a manganese oxide additive. Cobalt-aluminum spinel supports have a high reduction temperature, which can lead to inadequate reduction of cobalt species.

[0009] Han et al. (Effect of support modification and precursor decomposition method on the properties of CoPt / ZrO2 Fischer-Tropsch catalysts[J].CatalysisToday,2021,375(1).) prepared precursors of a series of CoPt / ZrO2 catalysts by plasma treatment to modify the ZrO2 support and / or decompose cobalt, thereby changing the support morphology. The synergistic effect of plasma modification of the support and precursor decomposition resulted in highly dispersed cobalt species (~1nm). These highly dispersed cobalt particles also had better reducing ability, but their TOF values ​​were low. Summary of the Invention

[0010] The first object of the present invention is to provide a cobalt-based Fischer-Tropsch catalyst.

[0011] The second object of the present invention is to provide a method for preparing the cobalt-based Fischer-Tropsch catalyst.

[0012] The third object of the present invention is to provide an application of the cobalt-based Fischer-Tropsch catalyst in Fischer-Tropsch synthesis.

[0013] The catalyst provided by the present invention can increase the C 5+ hydrocarbons and has the characteristics of low methane selectivity.

[0014] In order to achieve the above objectives, the present invention adopts the following technical solutions:

[0015] In one aspect, the present invention provides a cobalt-based Fischer-Tropsch catalyst, wherein the cobalt-based Fischer-Tropsch catalyst comprises a carrier and an active component supported on the carrier;

[0016] The carrier is a manganese-modified composite carrier Mn-TiO2 / MgO;

[0017] The active component is generally represented by the atomic ratio: Co 100 A a B b ; wherein A is selected from at least one of Ru, Pt, and Ir, B is selected from at least one of Zr and Nb, the value range of a is 0 to 5, and the value range of b is 0 to 15.

[0018] In some specific embodiments of the present invention, in the cobalt-based Fischer-Tropsch catalyst, the mass proportion of the active component is 20% to 50%, and the mass proportion of the carrier is 50% to 80%.

[0019] In some specific embodiments of the present invention, in the cobalt-based Fischer-Tropsch catalyst, the mass proportion of the active component is 20% to 35%, and the mass proportion of the carrier is 65% to 80%.

[0020] In some specific embodiments of the present invention, in the manganese-modified composite support Mn-TiO2 / MgO, the molar ratio of manganese to magnesium is 1:(0.1-25), and the molar ratio of manganese to titanium is 1:(0.1-25).

[0021] In some specific embodiments of the present invention, in the manganese-modified composite support Mn-TiO2 / MgO, the molar ratio of manganese to magnesium is 1:(1-15), and the molar ratio of manganese to titanium is 1:(1-15).

[0022] In some specific embodiments of the present invention, the active component Co 100 A a B b In the equation, the value range of a is 0.1 to 2, and the value range of b is 5 to 10.

[0023] In some specific embodiments of the present invention, the active component Co 100 A a B b In the equation, the value of a ranges from 0.3 to 1.

[0024] In some specific embodiments of the present invention, the specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 80 to 220 m 2 / g, preferably 96 to 209 m 2 / g; pore volume is 0.2~0.7cm 3 / g, preferably 0.24 to 0.65 cm 3 / g; the pore diameter is 5 to 35 nm, preferably 8 to 30 nm.

[0025] In some specific embodiments of the present invention, the vector is prepared by the following steps:

[0026] dissolving a manganese source, a magnesium source and a titanium source in an alcohol solvent to obtain a mixed solution A;

[0027] After adding mesoporous silica to the mixed solution A, heating and stirring to form a mixture B;

[0028] Adding an epoxy compound to the mixture B, stirring until the mixture forms a gel, and then aging the mixture;

[0029] drying and calcining the mixture obtained by aging;

[0030] The calcined solid was treated with a hot alkaline solution and centrifuged to obtain solid C;

[0031] Ethyl orthosilicate is dissolved in an alcohol solvent to form a mixed solution D; the mixed solution D is then mixed with a solid substance C for immersion, followed by drying and calcination to obtain a manganese-modified composite support Mn-TiO2 / MgO.

[0032] The alcohol solvent is preferably at least one of ethanol, ethylene glycol or glycerol; the alcohol solvent also serves as a dispersant and a stabilizer, and is preferably ethanol.

[0033] The mesoporous silica is used as a template for forming non-silicon mesoporous materials, and is preferably SBA-15 or KIT-6. The molar number of the mesoporous silica is preferably 3 to 4 times the total molar number of the metal elements.

[0034] The epoxy compound acts as a gel accelerator, captures protons in the system, and promotes the hydrolysis and polymerization of hydrated metal ions; the epoxy compound is preferably selected from propylene oxide, methyl propylene oxide, and the like.

[0035] The ethyl orthosilicate acts as a surface modifier, condensing with hydroxyl groups in the skeleton to reduce stress formed by dehydration condensation between hydroxyl groups in the pores, thereby enhancing the strength of the skeleton and consuming part of the hydroxyl groups and remaining water on the surface.

[0036] After calcination, the mixture is treated with a hot alkaline solution to remove silicon oxide. The hot alkaline solution is, for example, a sodium hydroxide solution at 75 to 100° C., such as the sodium hydroxide solution at 80° C. used in the examples.

[0037] In some specific embodiments of the present invention, mesoporous silica is added to the mixed solution A, and the mixture is heated to 60-85° C. and stirred for 4-6 hours to form the mixture B.

[0038] In some specific embodiments of the present invention, the aging is carried out in a water bath at 60-85°C.

[0039] In some specific embodiments of the present invention, the manganese source is selected from at least one of manganese nitrate and manganese acetate.

[0040] In some specific embodiments of the present invention, the manganese source is manganese nitrate.

[0041] In some specific embodiments of the present invention, the magnesium source is selected from at least one of magnesium nitrate, magnesium acetate, and magnesium chloride.

[0042] In some specific embodiments of the present invention, the magnesium source is magnesium nitrate.

[0043] In some specific embodiments of the present invention, the titanium source is selected from at least one of titanium sulfate, butyl titanate, tetraisopropyl titanate, and titanium chloride.

[0044] In some specific embodiments of the present invention, the titanium source is titanium sulfate.

[0045] In some specific embodiments of the present invention, in the solution A, the molar number of the alcohol solvent is 1 to 40 times the total molar number of the added metal elements.

[0046] In some specific embodiments of the present invention, in the solution C, the molar number of the alcohol solvent is 1 to 40 times the molar number of the added tetraethyl orthosilicate.

[0047] In some specific embodiments of the present invention, the molar number of the epoxy compound is 1 to 15 times the total molar number of the added metal elements.

[0048] In some specific embodiments of the present invention, the molar number of the epoxy compound is 4 to 10 times the total molar number of the added metal elements.

[0049] In some specific embodiments of the present invention, the drying temperature of the aging mixture is 60-120°C, and the drying time is 6-24 hours; the calcination temperature is 550-750°C, and the calcination time is 2-4 hours; for example, the calcination temperature is 600°C, and the heating rate can be 1°C / min, etc.

[0050] In some specific embodiments of the present invention, the solid object C is soaked in the mixed solution D for 1 to 3 times, each time for 3 to 6 hours.

[0051] In some specific embodiments of the present invention, the soaked solid C is dried at a temperature of 60-120° C. for 4-24 hours, and calcined at a temperature of 400-750° C. for 3-12 hours.

[0052] Another aspect of the present invention provides a method for preparing any one of the above cobalt-based Fischer-Tropsch catalysts, wherein the preparation method comprises the following steps:

[0053] Dissolve the soluble salt containing the active ingredient in deionized water to prepare a mixed solution I with a volume equal to or in excess of the water absorption capacity of the carrier;

[0054] The mixed solution I is added dropwise onto the support to form a mixture I, which is allowed to stand, dried, and calcined to obtain the cobalt-based Fischer-Tropsch catalyst.

[0055] The water absorption capacity of the carrier is obtained by testing the water absorption rate of the carrier in advance.

[0056] In some specific embodiments of the present invention, the mixture I is formed and then allowed to stand for 12 to 24 hours.

[0057] In some specific embodiments of the present invention, the cobalt source in the soluble salt containing the active component is selected from at least one of cobalt nitrate, cobalt acetate, cobalt carbonate, cobalt bicarbonate, and cobalt sulfate.

[0058] In some specific embodiments of the present invention, the cobalt source in the soluble salt containing the active ingredient is cobalt nitrate.

[0059] In some specific embodiments of the present invention, when the active component further includes metal A and / or metal B, the soluble salt containing the active component further includes nitrate, chloride or oxalate of metal A and / or metal B.

[0060] In some specific embodiments of the present invention, when the active component further includes metal A and / or metal B, the soluble salt containing the active component further includes at least one of the following: ruthenium trichloride, chloroplatinic acid, hydrated iridium trichloride, zirconium nitrate pentahydrate, and niobium oxalate.

[0061] In some specific embodiments of the present invention, the drying temperature of the mixture I after standing is 80-120° C., and the drying time is 6-24 hours.

[0062] In some specific embodiments of the present invention, the calcination temperature of the dried mixture I is 450-600° C., and the calcination time is 2-4 hours.

[0063] In another aspect, the present invention provides a use of any one of the above cobalt-based Fischer-Tropsch catalysts in a Fischer-Tropsch synthesis reaction, wherein the cobalt-based Fischer-Tropsch catalyst is reduced and activated by hydrogen-containing gas before use.

[0064] In some specific embodiments of the present invention, the Fischer-Tropsch synthesis reaction is carried out in a fixed bed reactor, and the reaction conditions include: reaction temperature of 200-260°C, feed gas V(H2) / V(CO)=1.5-3, reaction pressure of 1.5-3MPa, space velocity of 800-2000h -1 .

[0065] The present invention uses the composite oxide Mn-TiO2 / MgO as a carrier, and its mesoporous structure has a large specific surface area and a smaller grain size, which produces more lattice defects. Different from the conventional impregnation method to introduce manganese additives into the catalyst active component, the present invention introduces manganese additives into the carrier skeleton, so that the manganese additives can exist in a highly dispersed form in the skeleton, and it is modified on the composite carrier. It can not only act as a structural additive to promote the dispersion of the active phase, but also act as an electronic additive to provide electrons to the cobalt phase to promote the reduction of the catalyst, thereby affecting the properties of the loaded active metal. In addition, the mild Co-Ti interaction formed by the composite carrier and the cobalt component is conducive to the reduction of cobalt oxide, so that the catalytic activity is significantly improved, which has the advantages of improving the reaction activity of the catalyst and increasing the C content in the Fischer-Tropsch product.5+ At the same time, by adding various effective additives, the adsorption and activation of carbon monoxide and hydrogen are enhanced, the reduction of Co is promoted, and high activity and C can be maintained at a lower reaction temperature. 5+ Hydrocarbon selectivity can effectively prevent carbon deposition at high temperatures, thereby improving catalyst stability.

[0066] When the cobalt-based Fischer-Tropsch catalyst of the present invention is used in the Fischer-Tropsch synthesis reaction, the C 5+ The catalyst is highly selective for hydrocarbons, has high activity and low methane selectivity, and is an efficient Fischer-Tropsch synthesis catalyst. The preparation method is simple and the catalyst is easy to use in industry. DETAILED DESCRIPTION

[0067] In order to explain the present invention more clearly, the present invention will be further described below in conjunction with preferred embodiments. It should be understood by those skilled in the art that the following specific description is illustrative rather than restrictive and should not be used to limit the scope of protection of the present invention.

[0068] The key to the cobalt-based Fischer-Tropsch catalyst of the present invention is that it uses a composite oxide Mn-TiO2 / MgO as a carrier, and its mesoporous structure has a large specific surface area and a smaller grain size, which produces more lattice defects. Different from the conventional impregnation method to introduce a manganese additive into the active component of the catalyst, the present invention introduces a manganese additive into the carrier skeleton, so that the manganese additive exists in a highly dispersed form in the skeleton, and is modified on the composite carrier. It can not only act as a structural additive to promote the dispersion of the active phase, but also act as an electronic additive to provide electrons to the cobalt phase to promote the reduction of the catalyst, thereby affecting the properties of the loaded active metal. In addition, the mild Co-Ti interaction formed by the composite carrier and the cobalt component is conducive to the reduction of the cobalt oxide, so that the catalytic activity is significantly improved, which has the advantages of improving the reaction activity of the catalyst and increasing the C content in the Fischer-Tropsch product. 5+ At the same time, by adding various effective additives, the adsorption and activation of carbon monoxide and hydrogen are enhanced, the reduction of Co is promoted, and high activity and C can be maintained at a lower reaction temperature. 5+ Hydrocarbon selectivity can effectively prevent carbon deposition at high temperatures, thereby improving catalyst stability.

[0069] Specifically, the cobalt-based Fischer-Tropsch catalyst provided by the present invention includes a carrier and an active component supported on the carrier; the carrier is a manganese-modified composite carrier Mn-TiO2 / MgO; the active component has the general formula in terms of atomic ratio: Co 100 A a B b ; wherein A is selected from at least one of Ru, Pt, and Ir, B is selected from at least one of Zr and Nb, the value range of a is 0 to 5, and the value range of b is 0 to 15.

[0070] In some specific embodiments of the present invention, in the cobalt-based Fischer-Tropsch catalyst, the mass proportion of the active component is 20% to 50%, and the mass proportion of the support is 50% to 80%. Preferably, the mass proportion of the active component is 20% to 35%, and the mass proportion of the support is 65% to 80%.

[0071] In some specific embodiments of the present invention, in the manganese-modified composite support Mn-TiO2 / MgO, the molar ratio of manganese to magnesium is 1:(0.1-25), and the molar ratio of manganese to titanium is 1:(0.1-25). Preferably, in the manganese-modified composite support Mn-TiO2 / MgO, the molar ratio of manganese to magnesium is 1:(1-15), and the molar ratio of manganese to titanium is 1:(1-15).

[0072] In some specific embodiments of the present invention, the active component Co 100 A a B b In the above example, the value range of a is 0.1 to 2, and the value range of b is 5 to 10. Preferably, the value range of a is 0.3 to 1.

[0073] In some specific embodiments of the present invention, the specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is preferably 80 to 220 m 2 / g, preferably 96 to 209 m 2 / g; pore volume is 0.2~0.7cm 3 / g, preferably 0.24 to 0.65 cm 3 / g; the pore diameter is 5 to 35 nm, preferably 8 to 30 nm.

[0074] The catalyst carrier of the present invention is prepared by the following steps:

[0075] dissolving a manganese source, a magnesium source and a titanium source in an alcohol solvent to obtain a mixed solution A;

[0076] After adding mesoporous silica to the mixed solution A, heating and stirring to form a mixture B;

[0077] Adding an epoxy compound to the mixture B, stirring until the mixture forms a gel, and then aging the mixture;

[0078] drying and calcining the mixture obtained by aging;

[0079] The calcined solid was treated with a hot alkaline solution and centrifuged to obtain solid C;

[0080] Ethyl orthosilicate is dissolved in an alcohol solvent to form a mixed solution D; the mixed solution D is then added to the solid C for soaking, followed by drying and calcination to obtain a manganese-modified composite support Mn-TiO2 / MgO.

[0081] During the preparation of the carrier, the manganese source is selected from at least one of manganese nitrate and manganese acetate, preferably manganese nitrate. The magnesium source is selected from at least one of magnesium nitrate, magnesium acetate, and magnesium chloride, preferably magnesium nitrate. The titanium source is selected from at least one of titanium sulfate, butyl titanate, tetraisopropyl titanate, and titanium chloride, preferably titanium sulfate.

[0082] The alcohol solvent is preferably selected from at least one of ethanol, ethylene glycol, or glycerol; the alcohol solvent also serves as a dispersant and stabilizer, preferably ethanol. In solution A, the molar amount of the alcohol solvent is preferably 1 to 40 times the total molar amount of the added metal elements. After adding mesoporous silica to the mixed solution A, the mixture is heated to 60 to 85°C and stirred for 4 to 6 hours to form solution B. In solution C, the molar amount of the alcohol solvent is preferably 1 to 40 times the molar amount of the added tetraethyl orthosilicate. The epoxy compound acts as a gelation accelerator, extracting protons from the system and promoting the hydrolysis and polymerization of hydrated metal ions. The epoxy compound is preferably selected from propylene oxide, methyl propylene oxide, and the like. The molar amount of the epoxy compound is preferably 1 to 15 times, more preferably 4 to 10 times, the total molar amount of the added metal elements. Aging is preferably carried out in a water bath at 60-85°C. The drying temperature of the aged mixture is preferably 60-120°C, and the drying time is preferably 6-24 hours. The calcination temperature is preferably 550-750°C, and the calcination time is preferably 2-4 hours. For example, the calcination temperature is 600°C, and the heating rate can be 1°C / min. The solid material C is preferably soaked in mixed solution D 1-3 times, each time for 3-6 hours. After soaking, the solid material C is preferably dried at a temperature of 60-120°C, and the drying time is preferably 4-24 hours. The calcination temperature is preferably 400-750°C, and the calcination time is preferably 3-12 hours.

[0083] The mesoporous silica is used as a template for forming non-silicon mesoporous materials, and is preferably SBA-15 or KIT-6. The molar number of the mesoporous silica is preferably 3 to 4 times the total molar number of the metal elements.

[0084] The ethyl orthosilicate acts as a surface modifier, condensing with hydroxyl groups in the skeleton to reduce stress caused by dehydration condensation between hydroxyl groups within the pores, thereby strengthening the skeleton while consuming some of the surface hydroxyl groups and remaining water. After calcination, the silicon oxide is removed using a hot alkaline solution, such as a sodium hydroxide solution at 75-100°C, more specifically an 80°C sodium hydroxide solution as used in the examples.

[0085] The preparation method of the cobalt-based Fischer-Tropsch catalyst of the present invention comprises the following steps:

[0086] Dissolve the soluble salt containing the active ingredient in deionized water to prepare a mixed solution I with a volume equal to or in excess of the water absorption capacity of the carrier;

[0087] The mixed solution I is added dropwise onto the support to form a mixture I, which is allowed to stand, dried, and calcined to obtain the cobalt-based Fischer-Tropsch catalyst.

[0088] The water absorption capacity of the carrier is obtained by testing the water absorption rate of the carrier in advance.

[0089] During the preparation of the catalyst, the cobalt source in the soluble salt containing the active component is preferably selected from at least one of cobalt nitrate, cobalt acetate, cobalt carbonate, cobalt bicarbonate, and cobalt sulfate, and is more preferably cobalt nitrate. In addition, when the active component also includes metal A and / or metal B, the soluble salt containing the active component also includes a nitrate, chloride, or oxalate of metal A and / or metal B. More preferably, when the active component also includes metal A and / or metal B, the soluble salt containing the active component also includes at least one of the following: ruthenium trichloride, chloroplatinic acid, hydrated iridium trichloride, zirconium nitrate pentahydrate, or niobium oxalate.

[0090] The mixture I after standing is preferably dried at a temperature of 80 to 120° C. for a drying time of 6 to 24 hours. The mixture I after drying is preferably calcined at a temperature of 450 to 600° C. for a calcination time of 2 to 4 hours. The standing time is preferably 12 to 24 hours.

[0091] The cobalt-based Fischer-Tropsch catalyst of the present invention is used in a Fischer-Tropsch synthesis reaction, and the cobalt-based Fischer-Tropsch catalyst is reduced and activated by hydrogen-containing gas before use. Preferably, the Fischer-Tropsch reaction is carried out in a fixed bed reactor, and the reaction conditions include: a reaction temperature of 200-260°C, a feed gas V(H2) / V(CO)=1.5-3, a reaction pressure of 1.5-3 MPa, and a space velocity of 800-2000 h -1 .

[0092] When the cobalt-based Fischer-Tropsch catalyst of the present invention is used in the Fischer-Tropsch synthesis reaction, the C 5+ The catalyst is highly selective for hydrocarbons, has high activity and low methane selectivity, and is an efficient Fischer-Tropsch synthesis catalyst. The preparation method is simple and the catalyst is easy to use in industry.

[0093] The present invention is described in more detail below with reference to some specific examples, in which all numerical values ​​(e.g., temperature, time, concentration, and weight, including ranges thereof) are generally approximate values ​​that can be appropriately changed (+) or (-) in increments of 0.1 or 1.0. All numerical values ​​are understood to be preceded by the term "about."

[0094] The conversion rate of the FTS reaction can be calculated based on a single reaction component. In the present invention, the CO conversion rate is used. In the embodiment, the conversion rate and selectivity are calculated by the following formulas:

[0095]

[0096]

[0097]

[0098] Wherein, A is the peak area of ​​the gas detected by the TCD detector;

[0099] C m is the C content of each substance;

[0100] X CO is the conversion rate of carbon monoxide;

[0101] S is the selectivity of each substance.

[0102] Example 1

[0103] This embodiment prepares a composite support Mn-TiO2 / MgO (Z1), comprising the following steps:

[0104] 1) Weigh 0.358 g of manganese nitrate (50 wt%), weigh the corresponding magnesium nitrate and titanium sulfate in a molar ratio of manganese to magnesium of 1:25 and a molar ratio of manganese to titanium of 1:6, stir thoroughly to dissolve, and then mix and dissolve in 2.81 g of anhydrous ethanol to obtain a mixed solution A.

[0105] 2) After adding 6 g of KIT-6 to the mixed solution A, the mixture was stirred at 65° C. for 4 h to form a mixture B.

[0106] 3) Add 14.15 g of propylene oxide to mixture B (Note: the molar number of propylene oxide is 4 times the total molar number of the added metal elements), stir thoroughly until it forms a gel, and age it in a water bath at 65°C.

[0107] 4) The mixture was transferred to a drying oven at 100°C and dried for 12 h, and then calcined at 600°C for 3 h with a heating rate of 1°C / min.

[0108] 5) The obtained solid was treated with 2 mol / L sodium hydroxide solution at 80°C and centrifuged to obtain solid C.

[0109] 6) Add 16.25 g of ethyl orthosilicate to 27.6 g of anhydrous ethanol, stir thoroughly to dissolve, add to solid C, and soak three times for 5 hours each time; then dry at 100°C for 12 hours and calcine at 540°C for 4 hours to obtain a composite support Mn-TiO2 / MgO, which is denoted as Z1.

[0110] Example 2

[0111] This example prepares a composite support Mn-TiO2 / MgO (Z2). The differences between the preparation process and that of Example 1 include:

[0112] The mass of manganese nitrate (50wt%) is 0.537g, the metal element molar ratio of manganese and magnesium is 1:1, the metal element molar ratio of manganese and titanium is 1:25, KIT-6 is replaced by SBA-15, and the molar number of propylene oxide is 7 times the total molar number of the added metal elements; in step 2), stirring at 60°C for 6h to form a mixture B; in step 3), the aging temperature is 60°C; in step 4), the mixture is transferred to a 120°C drying oven and dried for 6h, and then calcined at 550°C for 4h; in step 6), after soaking, dried at 60°C for 24h, and calcined at 750°C for 3h.

[0113] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z2.

[0114] Example 3

[0115] This example prepares a composite support Mn-TiO2 / MgO (Z3). The differences between the preparation process and that of Example 1 include:

[0116] Manganese nitrate (50 wt%) weighs 0.215 g, the molar ratio of manganese to magnesium is 1:5, and the molar ratio of manganese to titanium is 1:5. The molar number of propylene oxide is 10 times the total molar number of the added metal elements. In step 2), the mixture is stirred at 80°C for 4 hours to form mixture B. In step 3), the aging temperature is 60°C. In step 4), the mixture is transferred to an 80°C drying oven and dried for 14 hours, followed by calcination at 600°C for 4 hours. In step 6), after soaking, the mixture is dried at 120°C for 4 hours and calcined at 700°C for 5 hours.

[0117] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z3.

[0118] Example 4

[0119] This example prepares a composite support Mn-TiO2 / MgO (Z4). The differences between the preparation process and that of Example 1 include:

[0120] The mass of manganese nitrate (50 wt%) is 0.358 g. The molar ratio of manganese to magnesium is 1:15, the molar ratio of manganese to titanium is 1:10, and the molar number of propylene oxide is 15 times the total molar number of the added metal elements. In step 2), stirring is performed at 60°C for 5 hours to form mixture B. In step 3), the aging temperature is 85°C. In step 4), the mixture is transferred to a drying oven at 90°C and dried for 12 hours, followed by calcination at 750°C for 3 hours. In step 6), after soaking, the mixture is dried at 80°C for 10 hours and calcined at 600°C for 10 hours.

[0121] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z4.

[0122] Example 5

[0123] This example prepares a composite support Mn-TiO2 / MgO (Z5). The differences between the preparation process and that of Example 1 include:

[0124] The mass of manganese nitrate (50 wt%) is 0.358 g. The molar ratio of manganese to magnesium is 1:10, and the molar ratio of manganese to titanium is 1:5. The molar number of propylene oxide is 8 times the total molar number of the added metal elements. In step 2), the mixture is stirred at 85°C for 4 hours to form mixture B. In step 3), the aging temperature is 75°C. In step 4), the mixture is transferred to a 60°C drying oven and dried for 24 hours, followed by calcination at 650°C for 4 hours. In step 6), after soaking, the mixture is dried at 90°C for 10 hours and calcined at 500°C for 12 hours.

[0125] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z5.

[0126] Example 6

[0127] This example prepares a composite support Mn-TiO2 / MgO (Z6). The differences between the preparation process and that of Example 1 include:

[0128] The mass of manganese acetate is 0.26 g. The molar ratio of manganese to magnesium (precursor: magnesium acetate) is 1:0.1, and the molar ratio of manganese to titanium (precursor: butyl titanate) is 1:15. The molar number of propylene oxide is 6 times the total molar number of the added metal elements. In step 2), the mixture is stirred at 70°C for 6 hours to form mixture B. In step 3), the aging temperature is 70°C. In step 4), the mixture is transferred to a drying oven at 100°C and dried for 12 hours, followed by calcination at 700°C for 2 hours. In step 6), after soaking, the mixture is dried at 100°C for 10 hours and calcined at 550°C for 12 hours.

[0129] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z6.

[0130] Example 7

[0131] This example prepares a composite support Mn-TiO2 / MgO (Z7). The preparation process is different from that of Example 1 in the following aspects:

[0132] The mass of manganese nitrate (50 wt%) was 0.537 g. The molar ratio of manganese to magnesium (precursor: magnesium chloride) was 1:13, and the molar ratio of manganese to titanium (precursor: tetraisopropyl titanate) was 1:1. The molar number of propylene oxide was 3 times the total molar number of the added metal elements. In step 2), the mixture was stirred at 70°C for 6 hours to form mixture B. In step 3), the aging temperature was 70°C. In step 4), the mixture was transferred to a drying oven at 110°C and dried for 20 hours, followed by calcination at 600°C for 4 hours.

[0133] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z7.

[0134] Example 8

[0135] This example prepares a composite support Mn-TiO2 / MgO (Z8). The differences between the preparation process and that of Example 1 include:

[0136] The mass of manganese nitrate (50 wt%) was 0.537 g. The molar ratio of manganese to magnesium was 1:20, and the molar ratio of manganese to titanium (precursor: titanium chloride) was 1:0.1. The molar number of propylene oxide was 11 times the total molar number of the added metal elements. In step 2), the mixture was stirred at 75°C for 5 hours to form mixture B. In step 3), the aging temperature was 75°C. In step 4), the mixture was transferred to a drying oven at 70°C and dried for 24 hours, followed by calcination at 650°C for 4 hours.

[0137] Other conditions were the same as those in Example 1, and a composite support Mn-TiO2 / MgO was obtained, which was denoted as Z8.

[0138] Example 9

[0139] In this example, the catalyst 30% Co was prepared using carrier Z1. 100 -70% Z1, and conduct catalytic evaluation on the catalyst, including the following processes:

[0140] 1) 147.8 g of cobalt nitrate hexahydrate was dissolved in 100 mL of water to prepare a solution of a certain concentration, and the solution was added dropwise to 70 g of the support Z1 prepared in Example 1 to form a mixture I. The mixture was allowed to stand for 18 h.

[0141] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a 30% Co catalyst.100 -70% Z1, where 30% and 70% represent the ratio of active component to carrier respectively, and the subscript in the active component represents the content ratio of each element in the active component.

[0142] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 120 m 2 / g, pore volume is 0.65cm 3 / g, pore size is 8nm.

[0143] 3) Catalyst evaluation in a fixed bed reactor:

[0144] First, pure hydrogen was introduced to reduce and activate the catalyst at a reduction temperature of 430°C, a pressure of 2.5 MPa, and a space velocity of 1000 h -1 , the reduction time is 8h.

[0145] The reaction conditions are: reaction temperature 216 ° C, raw gas V (H2) / V (CO) = 2, reaction pressure 2.5 MPa, space velocity 1000h -1 After the reaction stabilized, samples were taken for analysis. The catalyst evaluation results are shown in Table 1.

[0146] Example 10

[0147] In this example, the catalyst 30% Co was prepared using carrier Z2. 100 Ru1-70% Z2, and the catalyst was evaluated for catalysis, including the following processes:

[0148] 1) 145.5 g of cobalt nitrate hexahydrate and 1.04 g of ruthenium trichloride were dissolved in 100 mL of water to prepare a solution of a certain concentration, which was added dropwise to 70 g of the support Z2 prepared in Example 2 to form a mixture I, which was allowed to stand for 12 h.

[0149] 2) Transfer the mixture I to an 80°C drying oven and dry for 24 hours, then calcine at 600°C for 2 hours to obtain a catalyst 30% Co 100 Ru1-70% Z2.

[0150] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 209 m 2 / g, pore volume is 0.3cm 3 / g, pore size is 13nm.

[0151] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0152] Example 11

[0153] In this example, the catalyst 30% Co was prepared using carrier Z3. 100 Pt 0.5-70% Z3, and conduct catalytic evaluation on the catalyst, including the following processes:

[0154] 1) 145.5 g of cobalt nitrate hexahydrate and 1.025 g of chloroplatinic acid were dissolved in 100 mL of water to prepare a solution of a certain concentration, and then added dropwise to 70 g of the carrier Z3 prepared in Example 3 to form a mixture I. The mixture was allowed to stand for 24 h.

[0155] 2) Transfer the mixture I to a drying oven at 120°C and dry for 6 hours, then calcine at 450°C for 4 hours to obtain a catalyst 30% Co 100 Pt 0.5 -70% Z3.

[0156] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 146 m 2 / g, pore volume is 0.47cm 3 / g, pore size is 26nm.

[0157] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0158] Example 12

[0159] In this example, the catalyst 30% Co was prepared using carrier Z4. 100 Ir2-70% Z4, and the catalyst was evaluated for catalysis, including the following process:

[0160] 1) 138.9 g of cobalt nitrate hexahydrate and 3.35 g of hydrated iridium trichloride were dissolved in 100 mL of water to prepare a solution of a certain concentration, which was then added dropwise to 70 g of the support Z4 prepared in Example 4 to form a mixture I, which was allowed to stand for 18 h.

[0161] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a 30% Co catalyst. 100 Ir2-70% Z4.

[0162] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 182 m 2 / g, pore volume is 0.51cm 3 / g, pore size is 12nm.

[0163] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0164] Example 13

[0165] In this example, the catalyst 35% Co was prepared using carrier Z5. 100 Pt 0.3 Zr 10-65% Z5, and conduct catalytic evaluation on the catalyst, including the following processes:

[0166] 1) 148.41 g of cobalt nitrate hexahydrate, 0.627 g of chloroplatinic acid, and 21.90 g of zirconium nitrate pentahydrate were dissolved in 100 ml of water to prepare a solution of a certain concentration. The solution was added dropwise to 65 g of the support Z5 prepared in Example 5 to form a mixture I, and the mixture was allowed to stand for 18 h.

[0167] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 35% Co 100 Pt 0.3 Zr 10 -65% Z5.

[0168] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 177 m 2 / g, pore volume is 0.27cm 3 / g, pore size is 26nm.

[0169] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0170] Example 14

[0171] In this example, the catalyst 35% Co was prepared using carrier Z6. 100 Ru 0.1 Zr 15 -65% Z6, and conduct catalytic evaluation on the catalyst, including the following processes:

[0172] 1) 140.00 g of cobalt nitrate hexahydrate, 0.1 g of ruthenium trichloride, and 30.98 g of zirconium nitrate pentahydrate were dissolved in 100 mL of water to prepare a solution of a certain concentration, which was then added dropwise to 65 g of the support Z6 prepared in Example 6 to form a mixture I, which was allowed to stand for 18 h.

[0173] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 35% Co 100 Ru 0.1 Zr 15 -65% Z6.

[0174] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 150 m 2 / g, pore volume is 0.44cm 3 / g, pore size is 16nm.

[0175] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0176] Example 15

[0177] In this example, the catalyst 20% Co was prepared using carrier Z7. 100 Ru5Zr5Nb8-80%Z7, and the catalyst was evaluated for catalysis, including the following processes:

[0178] 1) 76.53 g of cobalt nitrate hexahydrate, 2.73 g of ruthenium trichloride, 5.65 g of zirconium nitrate pentahydrate, and 11.30 g of niobium oxalate were dissolved in 100 mL of water to prepare a solution of a certain concentration. The solution was added dropwise to 80 g of the support Z3 prepared in Example 3 to form a mixture I, and the mixture was allowed to stand for 18 h.

[0179] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 20% Co 100 Ru5Zr5Nb8-80%Z7.

[0180] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 164 m 2 / g, pore volume is 0.41cm 3 / g, pore size is 22nm.

[0181] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0182] Example 16

[0183] In this example, the catalyst 35% Co was prepared using carrier Z8. 100 Ru1Ir2Zr7-65%Z8, and the catalyst was evaluated for catalysis, including the following processes:

[0184] 1) 145.03 g of cobalt nitrate hexahydrate, 1.034 g of ruthenium trichloride, 14.98 g of zirconium nitrate pentahydrate, and 6.76 g of iridium trichloride hydrate were dissolved in 100 mL of water to prepare a solution of a certain concentration. The solution was added dropwise to 80 g of the support Z3 prepared in Example 3 to form a mixture I, and the mixture was allowed to stand for 18 h.

[0185] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 35% Co 100 Ru1Ir2Zr7-65%Z8.

[0186] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 131 m 2 / g, pore volume is 0.24cm 3 / g, pore size is 30nm.

[0187] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0188] Example 17

[0189] In this example, the catalyst 35% Co was prepared using carrier Z3. 100 Pt 0.5 Nb8-65% Z3, and the catalyst was evaluated for catalysis, including the following processes:

[0190] 1) 151.03 g of cobalt nitrate hexahydrate, 1.066 g of chloroplatinic acid, and 22.38 g of niobium oxalate were dissolved in 100 mL of water to prepare a solution of a certain concentration. The solution was then added dropwise to 65 g of the support Z3 prepared in Example 3 to form a mixture I, which was allowed to stand for 18 h.

[0191] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 35% Co 100 Pt 0.5 Nb8-65%Z3.

[0192] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 146 m 2 / g, pore volume is 0.46cm 3 / g, pore size is 23nm.

[0193] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0194] Example 18

[0195] In this example, the catalyst 50% Co was prepared using carrier Z3. 100 Pt 0.3 Nb5Zr5-50%Z3, and the catalyst was evaluated for catalysis, including the following processes:

[0196] 1) 211.557 g of cobalt nitrate hexahydrate, 0.8938 g of chloroplatinic acid, 19.56 g of niobium oxalate, and 15.6 g of zirconium nitrate pentahydrate were dissolved in 100 mL of water to prepare a solution of a certain concentration. The solution was added dropwise to 50 g of the support Z3 prepared in Example 3 to form a mixture I, and the mixture was allowed to stand for 18 h.

[0197] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 50% Co 100 Pt 0.3 Nb5Zr5-50%Z3.

[0198] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 96 m 2 / g, pore volume is 0.42cm 3 / g, pore size is 27nm.

[0199] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0200] Example 19

[0201] In this example, the catalyst 20% Co was prepared using carrier Z3. 100 Ru 1.5 Zr 10 -80% Z3, and conduct catalytic evaluation on the catalyst, including the following processes:

[0202] 1) 84.39 g of cobalt nitrate hexahydrate, 0.894 g of ruthenium trichloride, and 12.45 g of zirconium nitrate pentahydrate were dissolved in 100 mL of water to prepare a solution of a certain concentration, which was then added dropwise to 80 g of the support Z3 prepared in Example 3 to form a mixture I, which was allowed to stand for 18 h.

[0203] 2) Transfer the mixture I to a drying oven at 100°C and dry for 12 hours, then calcine at 540°C for 4 hours to obtain a catalyst 20% Co 100 Ru 1.5 Zr 10 -80% Z3.

[0204] The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 142 m 2 / g, pore volume is 0.43cm 3 / g, pore size is 29nm.

[0205] 3) Catalyst reduction conditions and evaluation reaction conditions are the same as those in Example 9. Specific evaluation results are shown in Table 1.

[0206] Comparative Example 1

[0207] In this comparative example, a composite carrier DZ1 was prepared and used as a carrier to prepare a catalyst 30% Co 100 -70% DZ1.

[0208] The only difference from Example 1 is that the mixed solution A contains only magnesium nitrate and titanium sulfate, and a composite carrier DZ1 is obtained.

[0209] The method of loading active components was the same as in Example 9 to obtain a catalyst with 30% Co 100 The catalyst reduction conditions and evaluation reaction conditions were the same as those in Example 9. The specific evaluation results are shown in Table 1.

[0210] Comparative Example 2

[0211] In this comparative example, a composite carrier DZ2 was prepared and used as a carrier to prepare a catalyst 30% Co 100 -70% DZ2.

[0212] The only difference from Example 1 is that the mixed solution A contains only titanium sulfate, and the composite support DZ2 is obtained.

[0213] The method of loading active components was the same as in Example 9 to obtain a catalyst with 30% Co 100 The catalyst reduction conditions and evaluation reaction conditions were the same as those in Example 9. The specific evaluation results are shown in Table 1.

[0214] Comparative Example 3

[0215] In this comparative example, a composite carrier DZ3 was prepared and used as a carrier to prepare a catalyst 30% Co 100 -70% DZ3.

[0216] The only difference from Example 1 is that the molar number of propylene oxide is 40 times the total molar number of the added metal elements, and a composite carrier DZ3 is obtained.

[0217] The method of loading active components was the same as in Example 9 to obtain a catalyst with 30% Co 100 -70% DZ3.

[0218] The reduction conditions of the catalyst and the evaluation reaction conditions were the same as those in Example 9. The specific evaluation results are shown in Table 1.

[0219] Comparative Example 4

[0220] In this comparative example, a composite carrier DZ4 was prepared and used as a carrier to prepare a catalyst 30% Co 100 -70% DZ4.

[0221] The only difference from Example 1 is that the molar number of propylene oxide is 0.7 times the total molar number of the added metal elements, and a composite carrier DZ4 is obtained.

[0222] The method of loading active components was the same as in Example 9 to obtain a catalyst with 30% Co 100 The catalyst reduction conditions and evaluation reaction conditions were the same as those in Example 9. The specific evaluation results are shown in Table 1.

[0223] Table 1 Catalyst evaluation results

[0224]

[0225] By comparing Comparative Examples 1 to 2 with Example 9, it can be seen that the Mn-modified composite support has better catalytic reaction activity and higher long-chain hydrocarbon selectivity than the single support.

[0226] By comparing Comparative Examples 1 to 4 with Examples 9 to 19, it can be seen that the addition of metals Ru, Pt, Ir, Zr, and Nb in the active components is beneficial to further improving the reaction activity of the catalyst.

[0227] By comparing Comparative Examples 3 to 4 with Examples 9 to 19, it can be seen that during the preparation of the carrier, when the molar number of propylene oxide is 1 to 15 times the total molar number of the added metal elements, the catalytic activity is higher after the active component is loaded. When it exceeds this range, the activity is significantly reduced.

[0228] Examples 20 to 25

[0229] The catalyst prepared in Example 9 was evaluated by changing the evaluation conditions. The evaluation conditions and results are shown in Table 2.

[0230] Table 2

[0231]

[0232] It can be seen from Examples 20-25 that within the given reaction conditions, the catalytic reaction performance of the catalyst of the present invention is good.

[0233] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not limitations on the implementation methods of the present invention. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made based on the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are still within the scope of protection of the present invention.

Claims

1. A cobalt-based Fischer-Tropsch catalyst, wherein: The cobalt-based Fischer-Tropsch catalyst includes a carrier and an active component supported on the carrier; The carrier is a manganese-modified composite carrier Mn-TiO2 / MgO, wherein the molar ratio of manganese to magnesium is 1:(0.1-25), and the molar ratio of manganese to titanium is 1:(0.1-25); The active component is generally represented by the atomic ratio: Co 100 A a B b ; Wherein, A is selected from at least one of Ru, Pt, and Ir, B is selected from at least one of Zr and Nb, the value range of a is 0 to 5, and the value range of b is 0 to 15; The carrier is prepared by the following steps: dissolving a manganese source, a magnesium source and a titanium source in an alcohol solvent to obtain a mixed solution A; After adding mesoporous silica to the mixed solution A, heating and stirring to form a mixture B; Adding an epoxy compound to the mixture B, stirring until it forms a gel, and then aging; the epoxy compound is propylene oxide or methylpropylene oxide; the molar number of the epoxy compound is 1 to 15 times the total molar number of the added metal element; drying and calcining the mixture obtained by aging; The calcined solid was treated with a hot alkaline solution and centrifuged to obtain solid C; Dissolve ethyl orthosilicate in an alcohol solvent to form a mixed solution D; then mix the mixed solution D with a solid substance C for immersion, followed by drying and calcination to obtain a manganese-modified composite support Mn-TiO2 / MgO.

2. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein In the cobalt-based Fischer-Tropsch catalyst, the mass proportion of the active component is 20% to 50%, and the mass proportion of the carrier is 50% to 80%.

3. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein The active component Co 100 A a B b In the equation, the value range of a is 0.1 to 2, and the value range of b is 5 to 10.

4. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein The specific surface area of ​​the cobalt-based Fischer-Tropsch catalyst is 80 to 220 m 2 / g, pore volume is 0.2~0.7cm 3 / g, pore size is 5~35nm.

5. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein The manganese source is selected from at least one of manganese nitrate and manganese acetate.

6. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein The magnesium source is selected from at least one of magnesium nitrate, magnesium acetate and magnesium chloride.

7. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein The titanium source is selected from at least one of butyl titanate, tetraisopropyl titanate, and titanium chloride.

8. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein The drying temperature of the aging mixture is 60-120° C., and the drying time is 6-24 hours; the calcination temperature is 550-750° C., and the calcination time is 2-4 hours.

9. The cobalt-based Fischer-Tropsch catalyst according to claim 1, wherein: The soaked solid C is dried at a temperature of 60 to 120° C. for 4 to 24 hours, and is calcined at a temperature of 400 to 750° C. for 3 to 12 hours.

10. A method for preparing the cobalt-based Fischer-Tropsch catalyst according to any one of claims 1 to 9, wherein: The preparation method comprises the following steps: Dissolve the soluble salt containing the active ingredient in deionized water to prepare a mixed solution I with a volume equal to or in excess of the water absorption capacity of the carrier; The mixed solution I is added dropwise onto the support to form a mixture I, which is allowed to stand, dried, and calcined to obtain the cobalt-based Fischer-Tropsch catalyst.

11. The preparation method according to claim 10, wherein The cobalt source in the soluble salt containing the active component is selected from at least one of cobalt nitrate, cobalt acetate, cobalt carbonate, cobalt bicarbonate and cobalt sulfate.

12. The preparation method according to claim 10, wherein When the active component further includes A metal and / or B metal, the soluble salt containing the active component further includes nitrate, chloride or oxalate of A metal and / or B metal.

13. The preparation method according to claim 12, wherein When the active component further includes metal A and / or metal B, the soluble salt containing the active component further includes at least one of the following: ruthenium trichloride, chloroplatinic acid, hydrated iridium trichloride, zirconium nitrate pentahydrate, and niobium oxalate.

14. The preparation method according to claim 10, wherein The drying temperature of the mixture I after standing is 80 to 120° C., and the drying time is 6 to 24 hours.

15. The preparation method according to claim 10, wherein The calcination temperature of the dried mixture I is 450-600° C., and the calcination time is 2-4 hours.

16. Use of the cobalt-based Fischer-Tropsch catalyst according to any one of claims 1 to 9 in a Fischer-Tropsch synthesis reaction, wherein: The cobalt-based Fischer-Tropsch catalyst is reduced and activated by hydrogen-containing gas before use.

17. The use according to claim 16, wherein: The Fischer-Tropsch synthesis reaction is carried out in a fixed bed reactor. The reaction conditions include: reaction temperature of 200-260°C, raw gas V(H2) / V(CO)=1.5-3, reaction pressure of 1.5-3MPa, and space velocity of 800-2000h -1 .

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