Cobalt alloy porous catalyst for Fischer-Tropsch reaction as well as preparation method and application of cobalt alloy porous catalyst

Abstract

The invention provides a cobalt alloy porous catalyst for Fischer-Tropsch reaction as well as a preparation method and application thereof. The cobalt alloy porous catalyst comprises the following raw material components: metal Co, metal Mn, metal B and metal Al, on the basis of the total use amount of the raw material components, the use amount of the metal B is 1-10 wt%, and the use amount of the metal Al is 10-90 wt%; the mass ratio of the metal Co to the metal Mn is 0.1 to 10; the metal B is selected from one or more of Mg, Zn, Cu, Fe, Ni, Cr, Ba and Ca; the mass ratio of the metal Co to the metal Mn is 0.1 to 10. According to the cobalt alloy porous catalyst prepared by the method, the Fischer-Tropsch reaction activity and CO selectivity are remarkably improved, the methane selectivity is reduced, and the cobalt alloy porous catalyst also has relatively high mechanical strength and is not easy to crush when being used in a reactor.

Description

Technical Field

[0001] The present invention relates to the technical field of syngas conversion, and particularly to a cobalt alloy porous catalyst for Fischer-Tropsch reaction, a preparation method thereof, and uses thereof. Background Art

[0002] Olefins include light olefins (C 2～ C4 ＝ ) and heavy olefins (C 5+ ＝ ), and are important high-value-added chemical raw materials. Light olefins are mainly used for producing plastics, synthetic textile materials, solvents, etc. Heavy olefins have higher added value and can be used as comonomers to produce plastics, polyethylene elastomers, surfactants, etc. At present, light olefins are mainly prepared by catalytic cracking of petroleum, while heavy olefins are mainly prepared by ethylene oligomerization. With the decreasing of petroleum resources and the sharp increase of olefin demand, it is urgent to develop a non-petroleum and sustainable olefin synthesis technology.

[0003] Syngas (a mixture of hydrogen and carbon monoxide) has a wide range of sources. Syngas is obtained by using coal, biomass or natural gas as raw materials. The technical route for producing olefins from syngas has attracted great attention. There are various process routes for preparing olefins from syngas. The route for directly preparing olefins from syngas has higher energy utilization efficiency and good economy, and mainly includes the bifunctional route and the Fischer-Tropsch reaction route. The bifunctional route mainly obtains light olefins, and the reaction conditions are relatively harsh. In contrast, the reaction conditions for directly preparing olefins from syngas via the Fischer-Tropsch route (FTO) are milder. In addition, by synthesizing olefins via the FTO route, not only light olefins can be obtained, but also heavy olefins with higher added value can be produced. In the research of C1 chemistry, directly preparing olefins from syngas has always been one of the important research directions of Fischer-Tropsch synthesis.

[0004] During the reaction process of directly synthesizing olefins from syngas, the selectivity of the reactor has a very important impact on the design of the catalyst. Different reactors have different requirements for the catalyst, including the shape, size, mechanical strength, and composition of the catalyst. Fixed-bed, fluidized-bed, and slurry-bed reactors are three types of Fischer-Tropsch synthesis reactors that are widely used on a large scale. The operating temperature of the fluidized-bed reactor is generally relatively high, about 350 °C, and it is generally used for high-temperature Fischer-Tropsch synthesis reactions (HTFT), such as high-temperature iron-melting catalysts. Low-temperature Fischer-Tropsch synthesis reactions (LTFT) generally use fixed-bed and slurry-bed reactors, such as iron-based catalysts prepared by precipitation and supported cobalt catalysts prepared by the impregnation method. The mechanical strength of the catalyst is an important indicator for industrial catalysts. In a fixed-bed reactor, the catalyst and diluent (generally millimeter-sized cylinders) are filled in the reactor. Fresh reaction gas enters from the upper part of the reactor, and the products leave the reactor from the lower part. If the mechanical strength of the catalyst is not high, it is easy to cause the catalyst to be crushed during the reaction, resulting in an increase in the pressure difference across the reaction bed. In extreme cases, it may even block the reactor, causing a shutdown accident. In slurry-bed and fluidized-bed reactors, the crushed catalyst will mix into the product, resulting in the loss of the catalyst and difficulty in separating the catalyst from the product. Therefore, developing catalysts with high mechanical strength is an important task for realizing the industrialization of directly synthesizing olefins from syngas. Summary of the Invention

[0005] In view of the above-mentioned disadvantages of the prior art, the purpose of the present invention is to provide a cobalt alloy porous catalyst for Fischer-Tropsch reaction, its preparation method and use, to solve the problems in the prior art.

[0006] To achieve the above object and other related objects, the present invention is obtained through the following technical solutions.

[0007] The present invention provides a cobalt alloy porous catalyst for Fischer-Tropsch reaction, comprising the following raw material components: metal Co, metal Mn, metal B, and metal Al; based on the total mass of the raw material components, the amount of metal B is 1-10 wt%, and the amount of metal Al is 10-90 wt%; the mass ratio of metal Co to metal Mn is 0.1-10; metal B is selected from one or more of Mg, Zn, Cu, Fe, Ni, Cr, Ba, and Ca.

[0008] For example, the amount of metal B can be 1-2 wt%, 2-3 wt%, 3-4 wt%, 4-5 wt%, 5-6 wt%, 6-7 wt%, 7-8 wt%, 8-9 wt%, 9-10 wt%, preferably 0.5-5 wt%. If the content of metal B is too high or too low, it will lead to a decrease in CO conversion and olefin selectivity, and an increase in methane selectivity.

[0009] For example, the mass ratio of Co to Mn can be 0.1 - 0.5, 0.5 - 1, 1 - 2, 2 - 3, 3 - 4, 4 - 5, 5 - 6, 7 - 7, 7 - 8, 8 - 9, 9 - 10, preferably 0.5 - 5. If the mass ratio of metallic Co to metallic Mn is too large or too small, the olefin selectivity will decrease.

[0010] For example, the amount of metallic Al used can be 10 - 20 wt%, 20 - 30 wt%, 30 - 40 wt%, 40 - 50 wt%, 50 - 60 wt%, 60 - 70 wt%, 70 - 80 wt%, 80 - 90 wt%. If the aluminum content is too high, the porosity inside the cobalt alloy porous catalyst will increase greatly, resulting in a decrease in the mechanical strength of the cobalt alloy porous catalyst; if the aluminum content is too low, the porosity inside the cobalt alloy porous catalyst will decrease greatly, affecting mass transfer and heat transfer during the Fischer-Tropsch reaction and reducing the catalytic activity and selectivity.

[0011] Preferably, the porosity of the cobalt alloy porous catalyst is 30 - 70%.

[0012] Preferably, the attrition rate of the cobalt alloy porous catalyst is 0.1 - 1.0% h -1 。

[0013] The present invention also provides a preparation method of the cobalt alloy porous catalyst as described above, including the following steps: immersing the precursor cobalt alloy in an alkaline solution, and obtaining the cobalt alloy porous catalyst after passivation treatment; the precursor cobalt alloy is formed by mixing and melting the raw material components.

[0014] More preferably, quenching and cooling are carried out after melting. Further preferably, the quenching and cooling is to 20 - 25 °C, and the cooling rate is 300 - 500 °C / s. Quenching and cooling means immersing the molten melt in water for cooling.

[0015] Preferably, the concentration of the alkaline solution is not less than 2 mol / L. The highest concentration of the alkaline solution can reach the saturation concentration. For example, the concentration of the alkaline solution can be 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, 10 mol / L.

[0016] Preferably, the alkaline solution is a potassium hydroxide solution and / or a sodium hydroxide solution.

[0017] Preferably, the temperature of the alkaline solution is 10 - 90 °C. For example, it can be 10 °C, 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, 90 °C.

[0018] Preferably, the immersion time is 2 - 20 h. For example, it can be 2 h, 5 h, 6 h, 10 h, 12 h, 14 h, 18 h, 20 h.

[0019] Preferably, the passivation treatment is to place it in an N2 atmosphere containing O2 for 0.5 to 15 h. For example, the passivation time can be 0.5 h, 1 h, 2 h, 5 h, 10 h, or 15 h.

[0020] More preferably, the content of O2 in the N2 atmosphere is 0.1 to 5%. For example, it can be 0.1%, 0.2%, 0.5%, 1%, 2%, 3%, 4%, or 5%.

[0021] More preferably, the passivation temperature is less than 30 °C. Further preferably, the passivation temperature is between 10 °C and 30 °C.

[0022] Preferably, the precursor cobalt alloy is crushed to a particle size of 50 to 300 mesh before being immersed in the alkaline solution. The precursor cobalt alloy with a small particle size facilitates the dissolution of aluminum.

[0023] Preferably, after the precursor cobalt alloy is immersed and taken out, it is washed, filtered, and dried. More preferably, the drying temperature is 150 to 250 °C.

[0024] The present invention also provides the use of the cobalt alloy porous catalyst as described above for catalyzing the Fischer-Tropsch reaction.

[0025] Preferably, in the Fischer-Tropsch reaction, the cobalt alloy porous catalyst increases the CO conversion rate to 70 to 90%, increases the olefin selectivity to 60 to 90%, reduces the methane selectivity to 1 to 10%, and reduces the attrition rate to 0.5 to 1%.

[0026] More preferably, in the Fischer-Tropsch reaction, the cobalt alloy porous catalyst increases the CO conversion rate to 75 to 90%, increases the olefin selectivity to 65 to 90%, reduces the methane selectivity to 1 to 8%, and reduces the attrition rate to 0.5 to 0.8%.

[0027] Further preferably, in the Fischer-Tropsch reaction, the cobalt alloy porous catalyst increases the CO conversion rate to 80 to 90%, increases the olefin selectivity to 75 to 90%, reduces the methane selectivity to 1 to 8%, and reduces the attrition rate to 0.5 to 0.8%.

[0028] Even more preferably, in the Fischer-Tropsch reaction, the cobalt alloy porous catalyst increases the CO conversion rate to 80 to 90%, increases the olefin selectivity to 80 to 90%, reduces the methane selectivity to 1 to 6%, and reduces the attrition rate to 0.5 to 0.6%.

[0029] Preferably, the cobalt alloy porous catalyst is subjected to a reduction pretreatment before the Fischer-Tropsch reaction.

[0030] More preferably, during the reduction pretreatment, the reducing gas is H2 and / or CO. Further preferably, the reducing gas further includes an inert gas, and the proportion of the inert gas is 50 to 95 vol%. Among them, the inert gas includes nitrogen, argon, and helium.

[0031] More preferably, during the reduction pretreatment, the reduction temperature is 150 to 600 °C, and the reduction time is 1 to 24 h. For example, the reduction temperature can be 150 to 200 °C, 250 to 300 °C, 320 to 400 °C, 400 to 500 °C, 500 to 600 °C, and preferably 200 to 400 °C. For example, the reduction time can be 1 to 3 h, 3 to 5 h, 5 to 10 h, 10 to 15 h, 15 to 20 h, 20 to 24 h, and preferably 3 to 10 h.

[0032] More preferably, during the reduction pretreatment, the volume space velocity of the reducing gas is 1000 to 20000 h -1 . For example, it can be 1000 to 2000 h -1 , 2000 to 3000 h -1 , 4000 to 6000 h -1 , 6000 to 8000 h -1 , 8000 to 10000 h -1 , 10000 to 15000 h -1 , 15000 to 20000 h -1 , and preferably 2000 to 8000 h -1 .

[0033] More preferably, during the reduction pretreatment, the pressure is 1 to 50 bar. For example, it can be 1 bar, 10 bar, 20 bar, 50 bar.

[0034] Preferably, in the Fischer-Tropsch reaction, the molar ratio of the raw material gases H2 and CO is 0.1 to 10. For example, it can be 0.1 to 0.5, 0.5 to 1, 1 to 2, 2 to 4, 4 to 6, 6 to 8, 8 to 10, and preferably 0.5 to 2.

[0035] Preferably, the reaction temperature of the Fischer-Tropsch reaction is 150 to 400 °C. For example, it can be 150 to 200 °C, 200 to 240 °C, 270 to 280 °C, 300 to 350 °C, 350 to 400 °C, and preferably 200 to 350 °C.

[0036] Preferably, the reaction pressure of the Fischer-Tropsch reaction is 1 to 50 bar. For example, it can be 1 to 5 bar, 10 to 15 bar, 20 to 30 bar, 30 to 40 bar, 40 to 50 bar, and preferably 1 to 30 bar.

[0037] Preferably, the volume space velocity of the Fischer-Tropsch reaction is 100-20000 h -1 . It can be, for example, 100-500 h -1 , 500-1000 h -1 , 1000-2000 h -1 , 5000-6000 h -1 , 6000-10000 h -1 , 10000-20000 h -1 , preferably 500-6000 h -1 .

[0038] In the preparation process of the cobalt alloy porous catalyst, the precursor cobalt alloy is immersed in an alkaline solution to dissolve aluminum, forming a cobalt alloy porous skeleton. Then, after passivation treatment, an oxide layer is formed on the surface of the cobalt alloy porous skeleton to protect the internal metal.

[0039] The cobalt alloy porous catalyst prepared in the present invention significantly improves the activity and olefin selectivity of the Fischer-Tropsch reaction, reduces the methane selectivity, and also has high mechanical strength and is not easily pulverized when used in a reactor, through composition optimization (Co / Mn), hierarchical pore structure and promoter (B) modification. In the Fischer-Tropsch reaction, the product distribution can be effectively adjusted by adjusting the composition of the cobalt alloy porous catalyst and reasonably selecting the activation conditions and reaction conditions. Specific Embodiments

[0040] The following specific embodiments illustrate the implementation manners of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0041] Before further describing the specific embodiments of the present invention, it should be understood that the protection scope of the present invention is not limited to the specific embodiments described below; it should also be understood that the terms used in the embodiments of the present invention are for the purpose of describing specific embodiments, rather than limiting the protection scope of the present invention. The test methods without specific conditions noted in the following embodiments are generally carried out under conventional conditions or according to the conditions recommended by each manufacturer.

[0042] When an embodiment gives a numerical range, it should be understood that unless otherwise specified in the present invention, any value between the two endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art of this technology. In addition to the specific methods, equipment, and materials used in the embodiments, according to the knowledge of those skilled in the art of this technology and the description of the present invention, any methods, equipment, and materials similar or equivalent to the methods, equipment, and materials described in the embodiments of the present invention can also be used to implement the present invention.

[0043] Example 1

[0044] This example provides a specific cobalt alloy porous catalyst, and the preparation method is as follows:

[0045] 1. Weigh and mix the metal powders of Co, Mn, Al, and Mg according to 30 / 15 / 50 / 5 (weight ratio), then melt them in an alloy melting furnace, and put the obtained melt into water to cool to room temperature. The cooling temperature is 300 °C / s to obtain a precursor cobalt alloy.

[0046] 2. Put the precursor cobalt alloy into a wet ball mill for grinding, crushing, and screening to obtain cobalt alloy powder with a particle size of 50 - 300 mesh. Put the cobalt alloy powder into a 2 mol / L NaOH aqueous solution at 90 °C and let it stand for 5 hours. Subsequently, rinse it twice with deionized water, and then passivate it in 1% O2 / N2 for 2 hours at room temperature to obtain the cobalt alloy porous catalyst.

[0047] This example also provides the application of the cobalt alloy porous catalyst in the Fischer - Tropsch reaction:

[0048] Carry out the Fischer - Tropsch reaction activity evaluation on the cobalt alloy porous catalyst prepared in this example. The results are shown in Table 2, and the activity evaluation process is as follows:

[0049] Weigh 1.0 g of the cobalt alloy porous catalyst, mix the cobalt alloy porous catalyst with quartz sand of 40 - 60 mesh with the same volume evenly, and then fill it into the middle constant - temperature area of a fixed - bed reactor. Seal the upper and lower ends of the cobalt alloy porous catalyst with quartz sand of 8 - 16 mesh. Pass a mixed gas (including H2 and N2, H2 / mixed gas = 10%) at a speed of 50 mL / min, heat it to 300 °C at a rate of 5 °C / min, and reduce it under normal pressure for 10 h. The reduction space velocity is 3000 h -1 , and after the reduction is completed, cool it to about 200 °C in the reduction atmosphere. Switch to the feed gas (including CO, H2, H2 / CO = 0.5), heat it to the reaction temperature of 250 °C at a rate of 5 °C / min, and the reaction pressure is 5 bar, and the reaction space velocity is 2000 h -1 .

[0050] Collect the reaction products, use gas chromatography (Shimadzu GC - 2014, GC - 2010plus) to analyze the types and contents of various components contained in the products, and calculate the conversion rate and product selectivity of this reaction accordingly. The calculation results are shown in Table 2.

[0051] Example 2

[0052] This example provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 1, except that in step 1), Zn is used to replace Mg, and the rest is the same as that of Example 1.

[0053] This example also provides the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction, which is the same as that in Example 1.

[0054] Example 3

[0055] This example provides a specific cobalt alloy porous catalyst, and the preparation method is as follows:

[0056] 1. Weigh and mix the metal powders of Co, Mn, Al, and Mg according to 13.3 / 26.7 / 50 / 10 (weight ratio), then melt them in an alloy melting furnace. The obtained melt is put into water and cooled to room temperature at a cooling rate of 300 °C / s to obtain the precursor cobalt alloy.

[0057] 2. Put the precursor cobalt alloy into a wet ball mill for grinding, crushing, and screening to obtain cobalt alloy powder with a particle size of 50 - 300 mesh. Put the cobalt alloy powder into a 4 mol / L NaOH aqueous solution at 50 °C and let it stand for 8 hours. Subsequently, rinse it twice with deionized water and then passivate it in 2% O2 / N2 for 1 hour at room temperature to obtain the cobalt alloy porous catalyst.

[0058] This example also provides the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction:

[0059] The Fischer-Tropsch reaction activity of the cobalt alloy porous catalyst prepared in this example was evaluated, and the results are shown in Table 2. The activity evaluation process is as follows:

[0060] Weigh 1.0 g of the cobalt alloy porous catalyst. After mixing the cobalt alloy porous catalyst with quartz sand of 40 - 60 mesh in equal volume evenly, fill it into the middle constant temperature area of a fixed-bed reactor. The upper and lower ends of the cobalt alloy porous catalyst are sealed with quartz sand of 8 - 16 mesh. Pass a mixed gas (including CO and N2, CO / mixed gas = 50%) at a rate of 50 mL / min, heat it to 320 °C at a rate of 5 °C / min, and reduce it at 10 bar for 20 h. The reduction space velocity is 3000 h -1 , and after the reduction is completed, cool it to about 200 °C in the reduction atmosphere. Switch to the raw material gas (including CO, H2, H2 / CO = 1), heat it to the reaction temperature of 350 °C at a rate of 5 °C / min, the reaction pressure is 5 bar, and the reaction space velocity is 1000 h -1 .

[0061] Collect the reaction products, use gas chromatography (Shimadzu GC-2014, GC-2010plus) to analyze the types and contents of various components in the products, and calculate the conversion rate and product selectivity of this reaction accordingly. The calculation results are shown in Table 2.

[0062] Examples 4 - 6

[0063] Examples 4 to 6 provide a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that: in step 1), the weight ratios of the metal powders of Co, Mn, Al, and Mg are different, which are 33.3 / 6.7 / 50 / 10, 3.6 / 36.4 / 50 / 10, and 36.4 / 3.6 / 50 / 10, respectively. The rest is the same as that of Example 3.

[0064] This example also provides the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction, which is the same as that of Example 3.

[0065] Examples 7 to 8

[0066] Examples 6 to 7 provide a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that: in step 1), the weight ratios of the metal powders of Co, Mn, Al, and Mg are different, which are 16.3 / 32.7 / 50 / 1 and 15 / 30 / 50 / 5, respectively. The rest is the same as that of Example 3.

[0067] This example also provides the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction, which is the same as that of Example 3.

[0068] Comparative Examples 1 to 2

[0069] Comparative Examples 1 to 2 are the comparative examples of Example 3. The preparation method of the cobalt alloy porous catalyst is different from that of Example 3 only in that: in step 1), the weight ratios of the metal powders of Co, Mn, Al, and Mg are different, which are 2.1 / 42.9 / 50 / 5 and 42.2 / 2.8 / 50 / 5, respectively. The rest is the same as that of Example 3.

[0070] Comparative Examples 1 to 2 also provide the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction, which is the same as that of Example 3.

[0071] Comparative Examples 3 to 4

[0072] Comparative Examples 3 to 4 are the comparative examples of Example 3. The preparation method of the cobalt alloy porous catalyst is different from that of Example 3 only in that: in step 1), the weight ratios of the metal powders of Co, Mn, Al, and Mg are different, which are 11.7 / 23.3 / 50 / 15 and 16.5 / 33 / 50 / 0.5, respectively. The rest is the same as that of Example 3.

[0073] Comparative Examples 3 to 4 also provide the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction, which is the same as that of Example 3.

[0074] Comparative Example 5

[0075] Comparative Example 5 is a comparative example of Example 3. The difference in the preparation method of the cobalt alloy porous catalyst from that of Example 3 is only that: in step 1), Al is not contained in the raw materials, and the weight ratio of the metal powders of Co, Mn, and Mg is 26.7 / 53.3 / 20. The rest is the same as in Example 3.

[0076] Comparative Example 5 also provides the application of the cobalt alloy porous catalyst in the Fischer-Tropsch reaction, which is the same as in Example 3.

[0077] Example 9

[0078] Example 9 provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that: in step 1), the metal powders of Co, Mn, Al, Mg, and Ni are weighed and mixed according to 40 / 4 / 50 / 5 / 1 (weight ratio), and then melted in an alloy melting furnace. The obtained melt is quenched and cooled to room temperature to obtain a precursor cobalt alloy. The rest is the same as in Example 3.

[0079] The cobalt alloy porous catalyst prepared in this example was evaluated for Fischer-Tropsch reaction activity. The results are shown in Table 2. The activity evaluation process is as follows:

[0080] Weigh 1.0 g of the cobalt alloy porous catalyst, mix the cobalt alloy porous catalyst evenly with quartz sand of 40-60 mesh in equal volume, and then fill it into the middle constant temperature area of a fixed bed reactor. The upper and lower ends of the cobalt alloy porous catalyst are sealed with quartz sand of 8-16 mesh. Pure H2 is introduced at a rate of 50 mL / min, heated to 200 °C at a rate of 5 °C / min, and reduced at 50 bar for 24 h. The reduction space velocity is 1000 h -1 , and after the reduction is completed, it is cooled in the reduction atmosphere. Switch to the feed gas (including CO, H2, H2 / CO = 2), heat it to the reaction temperature of 270 °C at a rate of 5 °C / min, the reaction pressure is 20 bar, and the reaction space velocity is 2000 h -1 .

[0081] Collect the reaction products, use gas chromatography (Shimadzu GC-2014, GC-2010plus) to analyze the types and contents of various components contained in the products, and calculate the conversion rate and product selectivity of this reaction accordingly. The calculation results are shown in Table 2.

[0082] Example 10

[0083] This example provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that: in step 1), the metal powders of Co, Mn, Al, and Cr are weighed and mixed according to 25 / 20 / 50 / 5 (weight ratio), and then melted in an alloy melting furnace. The obtained melt is quenched and cooled to room temperature to obtain a precursor cobalt alloy. The rest is the same as in Example 3.

[0084] The cobalt alloy porous catalyst prepared in this example was evaluated for Fischer-Tropsch reaction activity. The results are shown in Table 2, and the activity evaluation process is as follows:

[0085] Weigh 1.0 g of the cobalt alloy porous catalyst. After mixing the cobalt alloy porous catalyst evenly with quartz sand of 40-60 mesh in equal volume, fill it into the middle constant-temperature area of a fixed-bed reactor, and seal the upper and lower ends of the cobalt alloy porous catalyst with quartz sand of 8-16 mesh. Pass a mixer (including H2 and N2, H2 / mixed gas = 10%) at a rate of 50 mL / min, heat it up to 250 °C at a rate of 5 °C / min, reduce it at 10 bar for 15 h, and the reduction space velocity is 10000 h -1 , and cool it down in the reduction atmosphere after the reduction is completed. Switch to the feed gas (including CO, H2, H2 / CO = 5), heat it up to the reaction temperature of 280 °C at a rate of 5 °C / min, the reaction pressure is 20 bar, and the reaction space velocity is 2000 h -1 .

[0086] Collect the reaction products, use gas chromatography (Shimadzu GC-2014, GC-2010plus) to analyze the types and contents of various components contained in the products, and calculate the conversion rate and product selectivity of this reaction accordingly. The calculation results are shown in Table 2.

[0087] Example 11

[0088] This example provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that in step 1), the metal powders of Co, Mn, Al, and Fe are weighed and mixed according to 5 / 40 / 50 / 5 (weight ratio), and then melted in an alloy melting furnace. The obtained melt is quenched and cooled to room temperature to obtain a precursor cobalt alloy. The rest is the same as in Example 3.

[0089] The cobalt alloy porous catalyst prepared in this example was evaluated for Fischer-Tropsch reaction activity. The results are shown in Table 2, and the activity evaluation process is as follows:

[0090] Weigh 1.0 g of the cobalt alloy porous catalyst. After mixing the cobalt alloy porous catalyst evenly with quartz sand of 40-60 mesh in equal volume, fill it into the middle constant-temperature area of a fixed-bed reactor, and seal the upper and lower ends of the cobalt alloy porous catalyst with quartz sand of 8-16 mesh. Pass pure CO at a rate of 50 mL / min, heat it up to 250 °C at a rate of 5 °C / min, reduce it at 20 bar for 20 h, and the reduction space velocity is 20000 h -1 , and cool it down in the reduction atmosphere after the reduction is completed. Switch to the feed gas (including CO, H2, H2 / CO = 1), heat it up to the reaction temperature of 300 °C at a rate of 5 °C / min, the reaction pressure is 5 bar, and the reaction space velocity is 6000 h-1 。

[0091] The reaction products were collected, and a gas chromatograph (Shimadzu GC-2014, GC-2010plus) was used to analyze the types and contents of various components contained in the products, and the conversion rate and product selectivity of this reaction were calculated accordingly. The calculation results are shown in Table 2.

[0092] Example 12

[0093] This example provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that in step 1), the metal powders of Co, Mn, Al, and Cu are weighed and mixed according to 52 / 26 / 20 / 2 (weight ratio), and then melted in an alloy melting furnace. The obtained melt is quenched and cooled to room temperature to obtain a precursor cobalt alloy. The rest is the same as in Example 3.

[0094] The cobalt alloy porous catalyst prepared in this example was evaluated for Fischer-Tropsch reaction activity. The results are shown in Table 2. The activity evaluation process is as follows:

[0095] Weigh 1.0 g of the cobalt alloy porous catalyst, mix the cobalt alloy porous catalyst with quartz sand of 40-60 mesh in equal volume evenly, and then fill it into the middle constant temperature area of a fixed bed reactor. The upper and lower ends of the cobalt alloy porous catalyst are filled with quartz sand of 8-16 mesh. A mixed gas (including H2 and Ar, H2 / mixed gas = 5%) is introduced at a rate of 50 mL / min, heated to 290 °C at a rate of 5 °C / min, and reduced at normal pressure for 10 h. The reduction space velocity is 1000 h -1 , and after the reduction is completed, it is cooled in a reducing atmosphere. Switch to the raw material gas (including CO and H2, H2 / CO = 10), heat it to the reaction temperature of 240 °C at a rate of 5 °C / min, the reaction pressure is 15 bar, and the reaction space velocity is 10000 h -1 。

[0096] The reaction products were collected, and a gas chromatograph (Shimadzu GC-2014, GC-2010plus) was used to analyze the types and contents of various components contained in the products, and the conversion rate and product selectivity of this reaction were calculated accordingly. The calculation results are shown in Table 2.

[0097] Example 13

[0098] This example provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that in step 1), the metal powders of Co, Mn, Al, and Ca are weighed and mixed according to 45 / 10 / 40 / 5 (weight ratio), and then melted in an alloy melting furnace. The obtained melt is quenched and cooled to room temperature to obtain a precursor cobalt alloy. The rest is the same as in Example 3.

[0099] The cobalt alloy porous catalyst prepared in this example was evaluated for Fischer-Tropsch reaction activity. The results are shown in Table 2. The activity evaluation process is as follows:

[0100] Weigh 1.0 g of the cobalt alloy porous catalyst. After mixing the cobalt alloy porous catalyst evenly with quartz sand of 40 - 60 mesh in equal volume, fill it into the middle constant temperature area of the fixed bed reactor. The upper and lower ends of the cobalt alloy porous catalyst are filled with quartz sand of 8 - 16 mesh. Introduce the mixed gas (including H2 and Ar, H2 / mixed gas = 5%) at a rate of 50 mL / min, heat it up to 350 °C at a rate of 5 °C / min, and reduce it at atmospheric pressure for 10 h. The reduction space velocity is 1000 h -1 , and cool it down in the reducing atmosphere after the reduction is completed. Switch to the feed gas (including CO and H2, H2 / CO = 2), heat it up to the reaction temperature of 280 °C at a rate of 5 °C / min, the reaction pressure is 15 bar, and the reaction space velocity is 2000 h -1 .

[0101] Collect the reaction products, use gas chromatography (Shimadzu GC-2014, GC-2010plus) to analyze the types and contents of various components in the products, and calculate the conversion rate and product selectivity of this reaction accordingly. The calculation results are shown in Table 2.

[0102] Example 14

[0103] This example provides a specific cobalt alloy porous catalyst. The preparation method is basically the same as that of Example 3, except that in step 1), the metal powders of Co, Mn, Al, and Ba are weighed and mixed according to 25 / 20 / 50 / 5 (weight ratio), and then melted in an alloy melting furnace. The obtained melt is quenched and cooled to room temperature to obtain the precursor cobalt alloy. The rest is the same as in Example 3.

[0104] The cobalt alloy porous catalyst prepared in this example was evaluated for Fischer-Tropsch reaction activity. The results are shown in Table 2. The activity evaluation process is as follows:

[0105] Weigh 1.0 g of the cobalt alloy porous catalyst. After mixing the cobalt alloy porous catalyst evenly with quartz sand of 40 - 60 mesh in equal volume, fill it into the middle constant temperature area of the fixed bed reactor. The upper and lower ends of the cobalt alloy porous catalyst are filled with quartz sand of 8 - 16 mesh. Introduce the mixed gas (including H2 and Ar, H2 / mixed gas = 10%) at a rate of 50 mL / min, heat it up to 320 °C at a rate of 5 °C / min, and reduce it at atmospheric pressure for 5 h. The reduction space velocity is 8000 h -1 , and cool it down in the reducing atmosphere after the reduction is completed. Switch to the feed gas (including CO and H2, H2 / CO = 1), heat it up to the reaction temperature of 270 °C at a rate of 5 °C / min, the reaction pressure is 15 bar, and the reaction space velocity is 1000 h -1 .

[0106] The reaction products were collected, and a gas chromatograph (Shimadzu GC-2014, GC-2010plus) was used to analyze the types and contents of various components contained in the products. Accordingly, the conversion rate and product selectivity of this reaction were calculated, and the calculation results are shown in Table 2.

[0107] Table 1

[0108]

[0109]

[0110] The wear rate and porosity of the cobalt alloy porous catalysts prepared in Examples 1 to 14 and Comparative Examples 1 to 5 were tested. The test methods are as follows, and the test results are shown in Table 2.

[0111] Wear rate: NB / SH / T 0964-2017 was adopted.

[0112] Porosity: The porosity of the catalyst was tested using a mercury porosimeter.

[0113] Table 2

[0114]

[0115]

[0116] The above embodiments merely illustrate the principles and effects of the present invention and are not used to limit the present invention. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present invention should still be covered by the claims of the present invention.

Claims

1. A cobalt alloy porous catalyst for Fischer-Tropsch reaction, characterized in that, It includes the following raw material components: metallic Co, metallic Mn, metallic B, and metallic Al; based on the total amount of the raw material components, the amount of metallic B is 1-10 wt%, and the amount of metallic Al is 10-90 wt%; the mass ratio of metallic Co to metallic Mn is 0.1-10; metallic B is selected from one or more of Mg, Zn, Cu, Fe, Ni, Cr, Ba, and Ca.

2. The cobalt alloy porous catalyst according to claim 1, wherein The porosity of the cobalt alloy porous catalyst is 30-70%.

3. The cobalt alloy porous catalyst according to claim 1, characterized in that, The attrition rate of the cobalt alloy porous catalyst is 0.1 to 1.0% h -1 .

4. A method for preparing a cobalt alloy porous catalyst according to any one of claims 1 to 3, characterized in that, It includes the following steps: immersing the precursor cobalt alloy in an alkaline solution, and obtaining the cobalt alloy porous catalyst after taking it out and performing passivation treatment. The precursor cobalt alloy is formed by mixing and melting the raw material components.

5. The preparation method according to claim 4, wherein, After melting, it is quenched and cooled.

6. The preparation method according to claim 5, characterized in that, It is quenched and cooled to 20-25 °C, and the cooling rate is 300-500 °C / s.

7. The preparation method according to claim 4, characterized in that, The concentration of the alkaline solution is not less than 2 mol / L. And / or, the alkaline solution is a potassium hydroxide solution and / or a sodium hydroxide solution. And / or, the temperature of the alkaline solution is 10-90 °C. And / or, the immersion time is 2-20 h. And / or, the passivation treatment is to place it in an N2 atmosphere containing O2 for treatment for 0.5-15 h. And / or, the precursor cobalt alloy is crushed to a particle size of 50-300 mesh before being immersed in the alkaline solution.

8. Use of the cobalt alloy porous catalyst according to any one of claims 1 to 3 for catalyzing the Fischer-Tropsch reaction.

9. The use according to claim 8, characterized in that, The cobalt alloy porous catalyst is subjected to reduction pretreatment before the Fischer-Tropsch reaction. And / or, in the Fischer-Tropsch reaction, the molar ratio of the raw material gases H2 and CO is 0.1-10. And / or, the reaction temperature of the Fischer-Tropsch reaction is 150-400 °C. And / or, the reaction pressure of the Fischer-Tropsch reaction is 1-50 bar. And / or, the space velocity of the Fischer-Tropsch reaction is 100 to 20,000 h -1 .

10. The use according to claim 9, characterized in that, During the reduction pretreatment, the reducing gas is H2 and / or CO. And / or, during the reduction pretreatment, the reduction temperature is 150-600 °C, and the reduction time is 1-24 h. And / or, during the reduction pretreatment, the volumetric space velocity of the reducing gas is 1000-20000 h -1 .

Images