Cobalt-based Fischer-Tropsch synthesis catalyst and preparation method and application thereof

Abstract

The invention belongs to the technical field of Fischer-Tropsch synthesis catalysts, and particularly relates to a cobalt-based Fischer-Tropsch synthesis catalyst and a preparation method and application thereof.The preparation method comprises the steps that 1, Ti, Mn and Co precursors and an alkaline precipitator I are subjected to a precipitation reaction, the pH value of a system is controlled to range from 1.5 to 3.5, and aging is conducted; an alkaline precipitant II is continuously added into the system for precipitation reaction, and the pH value of the system is controlled to be 6 or above until all metal ions are precipitated; (2) filtering and washing the obtained precipitate to obtain a precipitate filter cake; and (3) uniformly mixing and kneading the precipitate filter cake, performing extrusion molding, drying and roasting to obtain the cobalt-based Fischer-Tropsch synthesis catalyst. The cobalt-based Fischer-Tropsch synthesis catalyst prepared by the invention can show excellent sintering resistance and carbon deposition resistance, and has stronger resistance to temperature fluctuation and hydrogen-carbon ratio fluctuation of feed gas in Fischer-Tropsch synthesis industrial application.

Description

Technical Field

[0001] The present invention belongs to the technical field of Fischer-Tropsch synthesis catalysts, and in particular relates to a cobalt-based Fischer-Tropsch synthesis catalyst having excellent sintering resistance and carbon deposition resistance, and a preparation method and application thereof. Background Art

[0002] Fischer-Tropsch synthesis is the core of coal-to-liquids and natural gas-to-liquids technology. The performance of Fischer-Tropsch synthesis catalysts directly determines the economy and competitiveness of the entire coal-to-liquids and natural gas-to-liquids technology. Commonly used Fischer-Tropsch synthesis catalysts mainly include iron-based Fischer-Tropsch synthesis catalysts and cobalt-based Fischer-Tropsch synthesis catalysts.

[0003] Compared with iron-based catalysts, cobalt-based catalysts have the significant advantages of high Fischer-Tropsch synthesis activity and low CO2 selectivity, and therefore have received more extensive attention and application worldwide. The active component cobalt of industrial cobalt-based Fischer-Tropsch synthesis catalysts is usually supported on carriers such as Al2O3, SiO2, TiO2, and ZrO2.

[0004] In the Fischer-Tropsch synthesis reaction using a cobalt-based catalyst in a fixed-bed reactor, since the reaction gas and the product have a long residence time in the catalyst bed, the product has a high selectivity for wax products with longer chain lengths, especially high-melting-point wax products with a melting point greater than 105°C, which cannot be produced using conventional petrochemical and Fischer-Tropsch synthesis technologies. However, the process of replacing catalysts in a fixed-bed reactor is complex and the cycle is long, so higher requirements are placed on the long-term stability of the catalyst. Since the Fischer-Tropsch synthesis reaction is a highly exothermic reaction, the discharge of reaction heat in a fixed-bed reactor is also more technically challenging than that of a Fischer-Tropsch reactor using a slurry bed or fluidized bed. In long-term industrial operation, fluctuations in the upstream gas supply system and the heat exchange system are inevitable, so the cobalt-based catalyst using a fixed-bed reactor needs to have a strong ability to cope with fluctuations in reaction temperature and raw gas composition. This requires the cobalt-based Fischer-Tropsch synthesis catalyst in the fixed-bed reactor to have a strong ability to resist sintering and carbon deposition to cope with system fluctuations caused by human or force majeure in industrial production. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the cobalt-based catalyst used in a fixed bed reactor has weak resistance to sintering and carbon deposition, poor tolerance to the upstream raw gas composition and reactor heat exchange fluctuations, and the technical problem that the existing cobalt-based catalyst has low wax selectivity when used in a fixed bed reactor.

[0006] Therefore, the object of the present invention is to provide a cobalt-based Fischer-Tropsch synthesis catalyst and a preparation method and application thereof in response to the above-mentioned technical problems. The prepared cobalt-based Fischer-Tropsch synthesis catalyst can exhibit excellent resistance to sintering and carbon deposition, and in the industrial application of Fischer-Tropsch synthesis, the catalyst has a stronger ability to resist temperature fluctuations and fluctuations in the hydrogen-carbon ratio of the raw gas.

[0007] In order to achieve the above objectives, the present invention provides the following technical solutions:

[0008] In a first aspect, a method for preparing a cobalt-based Fischer-Tropsch synthesis catalyst is provided, comprising the following steps:

[0009] (1) contacting a Ti precursor, a Mn precursor and a Co precursor with an alkaline precipitant I to carry out a precipitation reaction (Ti ions are precipitated), controlling the pH value of the system to be between 1.5 and 3.5 (for example, 2.0, 2.5, 3.0), and performing an aging treatment (under these conditions); then continuing to add an alkaline precipitant II to the system for a precipitation reaction, controlling the pH value of the system to be 6 or above (for example, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10.0, 10.5, 11), until all metal ions are precipitated, and then performing an aging treatment to obtain a precipitate;

[0010] (2) filtering and washing the precipitate obtained in step (1) to obtain a precipitate filter cake;

[0011] (3) The precipitated filter cake is placed in a kneader and kneaded evenly, and then extruded into strips, and then dried and calcined to obtain a cobalt-based Fischer-Tropsch synthesis catalyst.

[0012] According to the preparation method provided by the present invention, in some embodiments, the alkaline precipitant I and the alkaline precipitant II are the same or different, and are each independently selected from one or more of ammonia water, sodium carbonate and sodium bicarbonate.

[0013] In some embodiments, the alkaline precipitant I and the alkaline precipitant II are different.

[0014] In some embodiments, the alkaline precipitant I is aqueous ammonia.

[0015] In some embodiments, the alkaline precipitant II is sodium carbonate or sodium bicarbonate.

[0016] In some embodiments, the Ti precursor is selected from one or more of titanium oxychloride, metatitanic acid, titanyl sulfate and titanium dioxide.

[0017] In some embodiments, the Mn precursor is selected from one or more of manganese nitrate, manganese acetate and manganese chloride.

[0018] In some embodiments, the Co precursor is selected from one or more of cobalt nitrate, cobalt acetate and cobalt chloride.

[0019] Before contacting with the alkaline precipitant, for example, a salt solution of a Ti precursor, a salt solution of a Mn precursor, and a salt solution of a Co precursor may be prepared first, and then mixed to form a mixed solution; or the Ti precursor, the Mn precursor, and the Co precursor may be mixed and added to water to form a mixed salt solution. The mixed salt solution may be added to the reaction device in parallel with the aqueous solution of the alkaline precipitant.

[0020] In some embodiments, in step (1), the concentration of the Ti salt solution may be in the range of 0.5-6 mol / L; the concentration of the Mn salt solution may be in the range of 0.1-6 mol / L; and the concentration of the Co salt solution may be in the range of 0.5-6 mol / L. Alternatively, a mixed salt solution containing a Ti precursor, a Mn precursor, and a Co precursor is prepared, and the concentration thereof is in the range of 0.1-6 mol / L, for example, 0.2 mol / L, 0.4 mol / L, 0.5 mol / L, 1.0 mol / L, 2.0 mol / L, 4.0 mol / L, 5.0 mol / L.

[0021] In step (1), the pH value of the system can be controlled to be between 1.5 and 3.5 by adding an amount of alkaline precipitant I; and the pH value of the system can be controlled to be 6 or above by adding an amount of alkaline precipitant II until all metal ions are precipitated.

[0022] In some embodiments, in step (1), the process conditions for adding alkaline precipitant I for precipitation reaction include: precipitation temperature is room temperature to 70°C (for example, 25°C, 30°C, 40°C, 50°C, 60°C, 65°C), and the system pH value is 1.5-3.5 (for example, 2.0, 2.5, 3.0); the process conditions for aging include: system pH value is 1.5-3.5 (for example, 2.0, 2.5, 3.0), aging temperature is room temperature to 70°C (for example, 25°C, 30°C, 40°C, 50°C, 60°C, 65°C), and aging time is 0.5-3h (for example, 1.0h, 1.5h, 2.0h, 2.5h).

[0023] In step (1), after adding the alkaline precipitant twice for precipitation, the final pH of the system is 6.0-11.0 (e.g., 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 10.5).

[0024] In step (1), the process conditions for adding the alkaline precipitant for the second precipitation reaction include: the temperature is room temperature to 70°C (for example, 25°C, 30°C, 40°C, 50°C, 60°C, 65°C), and the pH of the system is 6.0-11.0 (for example, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 10.5); the process conditions for aging include: the pH of the system H is 6.0-11.0 (for example, 6.5, 7.0, 7.5, 8.0, 8.5, 9.0, 9.5, 10, 10.5), the aging temperature is from room temperature to 70°C (for example, 25°C, 30°C, 40°C, 50°C, 60°C, 65°C), and the aging time is 1-5h (for example, 1.5h, 2.0h, 2.5h, 3.0h, 3.5h, 4.0h, 4.5h).

[0025] In some embodiments, in step (2), the obtained precipitate is washed until the conductivity of the washing liquid is less than 2000 μs / cm, for example, 300 μs / cm, 400 μs / cm, 500 μs / cm, 800 μs / cm, 1000 μs / cm, 1200 μs / cm, 1500 μs / cm, 1800 μs / cm.

[0026] In some embodiments, in step (3), the kneading process conditions include: at room temperature, the kneading time is 15 min-180 min, for example, 20 min, 30 min, 40 min, 60 min, 80 min, 90 min, 120 min, 150 min.

[0027] In some embodiments, in step (3), the process conditions for extrusion molding include: at room temperature, an extrusion pressure of 20N-600N, for example, 50N, 100N, 200N, 300N, 400N, 450N, 500N.

[0028] In some embodiments, in step (3), the drying process conditions include: a drying temperature of 100-150°C (e.g., 110°C, 120°C, 140°C), and a drying time of 2-10h (e.g., 2.5h, 4h, 5h, 6h, 8h).

[0029] In some embodiments, in step (3), the calcination process conditions include: a calcination temperature of 350-700°C (e.g., 400°C, 450°C, 500°C, 550°C, 600°C, 650°C), and a calcination time of 2-5h (e.g., 2.5h, 3h, 3.5h, 4h, 4.5h).

[0030] In some embodiments, in step (1), the molar ratio of the Ti precursor to the Co precursor is 0.6 / 1-10 / 1, for example, 0.7 / 1, 0.8 / 1, 0.9 / 1, 1 / 1, 1.2 / 1, 1.5 / 1, 1.8 / 1, 2 / 1, 4 / 1, 5 / 1, 6 / 1, 8 / 1, 9 / 1;

[0031] In some embodiments, in step (1), the molar ratio of the Co precursor to the Mn precursor is 10 / 1-100 / 1, for example, 12 / 1, 15 / 1, 18 / 1, 20 / 1, 25 / 1, 28 / 1, 30 / 1, 40 / 1, 50 / 1, 60 / 1, 80 / 1, 90 / 1.

[0032] In a second aspect, a cobalt-based Fischer-Tropsch synthesis catalyst is provided, wherein the cobalt-based Fischer-Tropsch synthesis catalyst comprises the following components:

[0033] Active ingredient cobalt, 15%-50wt% (e.g., 16wt%, 18wt%, 20wt%, 22wt%, 25wt%, 28wt%, 30wt%, 35wt%, 40wt%, 45wt%);

[0034] Auxiliary component Mn, 0.2%-2.5wt% (e.g., 0.25wt%, 0.30wt%, 0.5wt%, 0.8wt%, 1.0wt%, 1.5wt%, 1.8wt%, 2.0wt%, 2.4wt%);

[0035] The remaining component is a titanium dioxide carrier;

[0036] In the catalyst, the Na ion content is ≤0.1% (e.g., 0.01wt%, 0.04wt%, 0.05wt%, 0.08wt%), and the Cl ion content is ≤0.3% (e.g., 0.01wt%, 0.03wt%, 0.05wt%, 0.08wt%, 0.1wt%, 0.15wt%, 0.2wt%).

[0037] According to the cobalt-based Fischer-Tropsch synthesis catalyst provided by the present invention, in some embodiments, the cobalt-based Fischer-Tropsch synthesis catalyst is prepared by the preparation method as described above.

[0038] In some embodiments, the titanium dioxide is composed of anatase titanium dioxide and rutile titanium dioxide, wherein the content of anatase titanium dioxide is greater than that of rutile titanium dioxide.

[0039] In a third aspect, there is provided a cobalt-based Fischer-Tropsch synthesis catalyst prepared by the preparation method described above or use of the cobalt-based Fischer-Tropsch synthesis catalyst described above in a Fischer-Tropsch synthesis reaction.

[0040] In the present invention, the Fischer-Tropsch synthesis reaction can be achieved by conventional means in the art, which will not be described in detail here. After calcination, the cobalt and manganese contained in the catalyst are both present as oxides, and hydrogen is used for activation before performance testing, and most of the cobalt is converted into metallic cobalt, while manganese still exists as oxides.

[0041] The applicant has found that it is very important to regulate the interaction between the active component Co and the TiO2 carrier and between Co and Mn in the Co-Mn-Ti catalyst system. The interaction between Co and Ti should be moderate. If the interaction is too strong, a cobalt titanate phase that inhibits activity will be generated, while if the interaction is too weak, the metal Co will easily sinter and grow. At the same time, the interaction between Co and Mn should be enhanced as much as possible to improve the catalyst's resistance to sintering and carbon deposition.

[0042] In the step-by-step precipitation method of the present invention, Ti in the system is first precipitated by controlling the process conditions, and then the active components and the auxiliary components are reprecipitated by controlling the process conditions. The anti-carbon deposition ability of the catalyst obtained by this precipitation process is significantly better than the process of precipitating Co, Mn and Ti in one step; the possible reason is that: the Co-Mn interaction in the catalyst obtained by this preparation process is stronger, so the catalyst shows strong anti-carbon deposition ability and anti-sintering property; at the same time, the interaction between Co and Ti in the catalyst is moderate and cobalt titanate is not generated, and the catalyst activity is high. In addition, the inventors have found through exploration that Na ions and Cl ions in cobalt-based catalysts have a significant inhibitory effect on the activity of the catalyst. The present invention controls the Na ion content in the catalyst to a lower range and the Cl ion content to be below 0.3%, so that the inhibitory effect on the catalyst is less affected, thereby improving the comprehensive performance of the catalyst.

[0043] The catalyst prepared by the present invention adopts a step-by-step coprecipitation method with TiO2 as a carrier, and shows excellent resistance to sintering and carbon deposition. In the industrial application of Fischer-Tropsch synthesis, the catalyst has stronger resistance to temperature fluctuations and fluctuations in the hydrogen-carbon ratio of the raw gas. In addition, the catalyst is also suitable for long-term operation under low hydrogen-carbon ratios, and the catalyst has higher wax selectivity under low hydrogen-carbon ratios; the catalyst has a solid wax yield of more than 70% under typical industrial reaction conditions, and a high melting point wax product yield of more than 105°C is more than 50%. DETAILED DESCRIPTION

[0044] In order to understand the technical features and content of the present invention in detail, the preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described in the embodiments, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. For those who do not specify specific conditions in the embodiments, they are carried out according to normal conditions or the conditions recommended by the manufacturer.

[0045] <Source of raw materials>

[0046] In the following examples and comparative examples, the sources of some reagents or raw materials used, without specifying the manufacturer, are all conventional products that can be purchased commercially.

[0047] Example 1

[0048] (1) Weighing 164 g of titanium tetrachloride, 148 g of cobalt nitrate (Co(NO3)2·6H2O), and 6.6 g of a 50 wt% manganese nitrate solution, dissolving them in 300 g of deionized water, and mixing them to obtain a mixed salt solution containing a titanium precursor, a cobalt precursor, and a manganese precursor;

[0049] Weigh 100g of deionized water and add it to a large beaker, and place the large beaker in a 40°C water bath; add the prepared mixed salt solution and 1mol / L ammonia water in parallel to the large beaker under mechanical stirring, and control the pH value of the solution system to 3.0 by the amount of ammonia water added, Ti ions precipitate, and stir under this condition for aging treatment for 1 hour; then use 1mol / L sodium carbonate solution as an alkaline precipitant and continue to add it dropwise to the large beaker until the pH of the solution system is 7.5; control the water bath temperature to 40°C, stop stirring, and age for 4 hours;

[0050] (2) filtering the precipitate obtained in step (1), and washing with deionized water until the conductivity of the washing liquid is less than 500 μs / cm, to obtain a precipitate filter cake;

[0051] (3) The precipitated filter cake obtained above was placed in a kneader and kneaded at room temperature. After kneading for 30 minutes, it was extruded into strips at room temperature and an extrusion pressure of 400N. The obtained molded product was then dried at 120°C for 10 hours and then calcined at 500°C for 3 hours to obtain a cobalt-based Fischer-Tropsch synthesis catalyst A1.

[0052] XRF detection results show that the content of Na ions in the cobalt-based Fischer-Tropsch synthesis catalyst A1 is 0.05wt%, and the content of Cl ions is 0.1wt%.

[0053] Example 2

[0054] The preparation method of the cobalt-based Fischer-Tropsch synthesis catalyst is similar to that of Example 1, except that in step (2), the precipitate obtained is washed with deionized water until the conductivity of the washing liquid is less than 1050 μs / cm; the remaining steps are the same as those of Example 1. Finally, the cobalt-based Fischer-Tropsch synthesis catalyst A2 is obtained.

[0055] XRF detection results show that the content of Na ions in the cobalt-based Fischer-Tropsch synthesis catalyst A2 is 0.10wt%, and the content of Cl ions is 0.2wt%.

[0056] Example 3

[0057] The preparation method of the cobalt-based Fischer-Tropsch synthesis catalyst is similar to that of Example 1, except that the amount of manganese nitrate solution in step (1) is adjusted to 9.9 g; the remaining steps are the same as those of Example 1. The cobalt-based Fischer-Tropsch synthesis catalyst A3 is finally obtained.

[0058] XRF detection results show that the content of Na ions in the cobalt-based Fischer-Tropsch synthesis catalyst A3 is 0.07wt%, and the content of Cl ions is 0.12wt%.

[0059] Example 4

[0060] The preparation method of the cobalt-based Fischer-Tropsch synthesis catalyst is similar to that of Example 1, except that the amount of cobalt nitrate (Co(NO3)2·6H2O) in step (1) is adjusted to 292 g; the remaining steps are the same as those of Example 1. The cobalt-based Fischer-Tropsch synthesis catalyst A4 is finally obtained.

[0061] XRF detection results show that the content of Na ions in the cobalt-based Fischer-Tropsch synthesis catalyst A4 is 0.09wt%, and the content of Cl ions is 0.12wt%.

[0062] Comparative Example 1

[0063] The preparation method of the cobalt-based Fischer-Tropsch synthesis catalyst is similar to that of Example 1, except that in step (2), the precipitate obtained is washed with deionized water until the conductivity of the washing liquid is less than 2500 μs / cm; the remaining steps are the same as those of Example 1. Finally, the cobalt-based Fischer-Tropsch synthesis catalyst D1 is obtained.

[0064] XRF detection results show that the content of Na ions in the cobalt-based Fischer-Tropsch synthesis catalyst D1 is 0.39wt%, and the content of Cl ions is 0.33wt%.

[0065] Comparative Example 2

[0066] (1) Weighing 164 g of titanium tetrachloride, 148 g of cobalt nitrate (Co(NO3)2·6H2O), and 6.6 g of a 50 wt% manganese nitrate solution, dissolving them in 300 g of deionized water, and mixing them to obtain a mixed salt solution containing a titanium precursor, a cobalt precursor, and a manganese precursor;

[0067] Weigh 100g of deionized water into a large beaker, and place the large beaker in a 40°C water bath; add the prepared mixed salt solution and a 1 mol / L sodium carbonate solution to the large beaker in parallel, control the pH value of the solution system to 7.0 by adding the sodium carbonate solution, control the system temperature to 40°C by using a water bath, stop stirring, and age for 4 hours;

[0068] (2) filtering the precipitate obtained in step (1), and washing with deionized water until the conductivity of the washing liquid is less than 500 μs / cm, to obtain a precipitate filter cake;

[0069] (3) The precipitated filter cake obtained above was placed in a kneader and kneaded at room temperature. After kneading for 30 minutes, it was extruded into strips. The obtained molded product was then dried at 120°C for 10 hours and then calcined at 500°C for 3 hours to obtain a cobalt-based Fischer-Tropsch synthesis catalyst D2.

[0070] XRF detection results show that the content of Na ions and the content of Cl ions in the Fischer-Tropsch synthesis catalyst D2 are estimated to be 0.05wt% and 0.10wt%.

[0071] The compositions of the catalysts obtained in the examples and comparative examples were measured using XRF, and the results are shown in Table 1.

[0072] The catalytic performance test and evaluation of the catalysts obtained in each embodiment and comparative example are as follows: 0.5 g of the catalyst obtained in each embodiment and comparative example is taken and loaded into a fixed bed reactor, first reduced for 12 hours in a H2 atmosphere, at a space velocity of 2000 ml / g / h, normal pressure, and a temperature of 350°C, and then the reducing gas is switched to a reaction gas to carry out the reaction. The reaction conditions are: raw gas group H2 / CO / N2=50.6 / 46.0 / 3.4, the space velocity is 3200 ml / g / h, the pressure is 2 MPa, and the temperature is 230°C. The CO conversion rate and methane selectivity are measured after 48 hours and 360 hours of reaction, respectively.

[0073] The wax product obtained was collected and cut using a molecular distillation device to cut out the components with a drop melting point of 110°C. The weight ratio of the components above 105°C to the weight of the wax was calculated, which was the yield of the wax above 110°C.

[0074] Table 1 Composition of components in the catalysts prepared in each embodiment and comparative example

[0075]

[0076]

[0077] Table 2 Performance evaluation results of catalysts prepared in various embodiments and comparative examples

[0078]

[0079] The components and contents of the catalysts prepared in each embodiment and comparative example are shown in Table 1. It can be found from the catalyst performance test results in Table 2 that each embodiment adopts step-by-step precipitation and controls the process conditions of each step of precipitation. The prepared catalyst is catalyzed under the condition of low hydrogen-carbon ratio (hydrogen-carbon ratio of 1.1) of the raw gas. The catalyst not only maintains a high CO conversion rate, but also maintains good stability under high CO conversion rate. Under this test condition, the selectivity of the catalyst for 110# high melting point wax is also maintained at more than 50%, and the selectivity of 110# wax does not change with the extension of reaction time. In Comparative Example 1, when too many Na ions or Cl ions remain in the catalyst, the catalyst activity is significantly reduced, while the catalyst prepared by the conventional method (Comparative Example 2) has a rapid decrease in the initial CO conversion rate of the catalyst and deactivation.

[0080] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the spirit of the present invention.

Claims

1. A method for preparing a cobalt-based Fischer-Tropsch synthesis catalyst, characterized in that: The steps include: (1) contacting a Ti precursor, a Mn precursor and a Co precursor with an alkaline precipitant I to carry out a precipitation reaction, controlling the pH value of the system to be between 1.5 and 3.5, and carrying out an aging treatment; then continuing to add an alkaline precipitant II to the system for a precipitation reaction, controlling the pH value of the system to be 6 or above, until all metal ions are precipitated, and then carrying out an aging treatment to obtain a precipitate; (2) filtering and washing the precipitate obtained in step (1) to obtain a precipitate filter cake; (3) The precipitated filter cake is placed in a kneader and kneaded evenly, and then extruded into strips, and then dried and calcined to obtain a cobalt-based Fischer-Tropsch synthesis catalyst.

2. The preparation method according to claim 1, characterized in that: The alkaline precipitant I and the alkaline precipitant II are the same or different, and are independently selected from one or more of ammonia water, sodium carbonate and sodium bicarbonate; Preferably, the alkaline precipitant I and the alkaline precipitant II are different, Preferably, the alkaline precipitant I is aqueous ammonia. Preferably, the alkaline precipitant II is sodium carbonate or sodium bicarbonate.

3. The preparation method according to claim 1 or 2, characterized in that: The Ti precursor is selected from one or more of titanium oxychloride, metatitanic acid, titanyl sulfate and titanium dioxide; and / or The Mn precursor is selected from one or more of manganese nitrate, manganese acetate and manganese chloride; and / or The Co precursor is selected from one or more of cobalt nitrate, cobalt acetate and cobalt chloride.

4. The preparation method according to any one of claims 1 to 3, characterized in that In step (1), the process conditions for adding alkaline precipitant I for precipitation reaction include: the temperature is room temperature to 70°C, and the system pH value is 1.5-3.5; the process conditions for aging include: the system pH value is 1.5-3.5, the aging temperature is room temperature to 70°C, and the aging time is 0.5-3h; and / or In step (1), the process conditions for adding the alkaline precipitant for the second precipitation reaction include: the temperature is room temperature to 70°C, and the pH of the system is 6.0-11.0; the process conditions for aging include: the pH of the system is 6.0-11.0, the aging temperature is room temperature to 70°C, and the aging time is 1-5h.

5. The preparation method according to any one of claims 1 to 4, characterized in that: In step (2), the obtained precipitate is washed until the conductivity of the washing liquid is less than 2000 μs / cm.

6. The preparation method according to any one of claims 1 to 5, characterized in that: In step (3), the kneading process conditions include: at room temperature, the kneading time is 15min-180min; and / or In step (3), the process conditions for extrusion molding include: at room temperature, the extrusion pressure is 20N-600N.

7. The preparation method according to any one of claims 1 to 6, characterized in that In step (3), the drying process conditions include: drying temperature of 100-150° C., drying time of 2-10 h; and / or In step (3), the calcination process conditions include: calcination temperature of 350-700°C and calcination time of 2-5h.

8. The preparation method according to any one of claims 1 to 7, characterized in that: In step (1), the molar ratio of the Ti precursor to the Co precursor is 0.6 / 1-10 / 1; The molar ratio of the Co precursor to the Mn precursor is 10 / 1-100 / 1.

9. A cobalt-based Fischer-Tropsch synthesis catalyst, characterized in that: The cobalt-based Fischer-Tropsch synthesis catalyst comprises the following components: Active ingredient cobalt, 15%-50wt%; Auxiliary component Mn, 0.2%-2.5wt%; The remaining component is a titanium dioxide carrier; In the catalyst, the Na ion content is ≤0.1%, and the Cl ion content is ≤0.3%; Preferably, the cobalt-based Fischer-Tropsch synthesis catalyst is prepared by the preparation method as described in any one of claims 1 to 8; Preferably, the titanium dioxide is composed of anatase crystalline titanium dioxide and rutile crystalline titanium dioxide, wherein the content of anatase crystalline titanium dioxide is greater than that of rutile crystalline titanium dioxide.

10. Use of the cobalt-based Fischer-Tropsch synthesis catalyst prepared by the preparation method according to any one of claims 1 to 8 or the cobalt-based Fischer-Tropsch synthesis catalyst according to claim 9 in a Fischer-Tropsch synthesis reaction.

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