Activated carbon carrier as well as preparation method and application thereof

Abstract

The invention relates to the technical field of selective hydrogenation catalysts, in particular to an activated carbon carrier and a preparation method and application thereof.The activated carbon carrier is at least prepared from activated carbon powder, bentonite, asphalt, methyl cellulose, polyvinyl alcohol powder and deionized water. The mechanical strength of the catalyst carrier is improved by optimizing a catalyst carrier formula system, so that the catalyst with high activity and high selectivity is prepared, the selective hydrogenation reaction requirement of 1, 3-butadiene is met, and the catalyst has a wide application prospect.

Description

Technical Field

[0001] The present invention relates to the technical field of selective hydrogenation catalysts, and specifically to an activated carbon carrier, a preparation method thereof, and an application thereof. Background Art

[0002] At present, most of the selective hydrogenation reactions of 1,3-butadiene use Pd / Al2O3 and Ni / Al2O3 as hydrogenation catalysts. The Pd / Al2O3 catalyst is generally Pd loaded on spherical and bar-shaped alumina carriers. This type of catalyst has a relatively single active component and high activity. During the reaction process, not only 1-butene is generated, but also excessive hydrogenation to form alkanes, resulting in low reaction selectivity. In addition, the price of Pd catalysts is very expensive, which further limits their application in industry. Chinese Patent (authorized publication number: CN103418378B) relates to a selective hydrogenation and de-acetylene catalyst for C4 fractions and a preparation method thereof. The catalyst carrier is alumina, with Pd as the main active component and Fe, Ni, and La as co-active components. This catalyst is simple to prepare, has high hydrogenation and de-acetylene activity, and a high reaction volume space velocity, but the selectivity of this catalyst is not ideal, and the loss rate of butadiene during the hydrogenation process is relatively high. The Ni / Al2O3 catalyst is prone to side reactions such as olefin polymerization, forming carbon deposits that cause blockage of the catalyst pores, resulting in catalyst poisoning and inactivation. Because the acidity of the alumina carrier itself causes one of the side reactions during the hydrogenation of dienes to be the polymerization of dienes into polymers, which is called green oil in industry. This type of polymer can adhere to the catalyst surface, affecting the catalyst activity, and at the same time, it will also block the pores, reducing the diffusion performance of the catalyst and further reducing the reaction performance of the catalyst. Summary of the Invention

[0003] In order to solve the above problems, the present invention improves the mechanical strength of the catalyst carrier by optimizing the catalyst carrier formulation system, and then prepares a catalyst with high activity and high selectivity to meet the requirements of the selective hydrogenation reaction of 1,3-butadiene, and has broad application prospects.

[0004] On the one hand, the present invention provides an activated carbon carrier, and its preparation raw materials at least include: activated carbon powder, bentonite, asphalt, methylcellulose, polyvinyl alcohol powder, deionized water.

[0005] By weight, the preparation raw materials of the activated carbon carrier at least include: 800-1000 parts of activated carbon powder, 100-250 parts of bentonite, 30-80 parts of asphalt, 20-50 parts of methylcellulose, 10-30 parts of polyvinyl alcohol powder, and 500-600 parts of deionized water.

[0006] As a preferred technical solution, the activated carbon powder is wood activated carbon powder or coconut shell activated carbon powder.

[0007] As a preferred technical solution, based on the total weight of the activated carbon powder and bentonite, the mass ratio of the bentonite is 10-25%, preferably 10-20%.

[0008] On the other hand, the present invention provides a method for preparing an activated carbon carrier, which at least includes the following steps:

[0009] (1) Add activated carbon powder, bentonite, asphalt, methyl cellulose, and polyvinyl alcohol powder into a container and mix to obtain a mixed powder;

[0010] (2) Add deionized water to the mixed powder, knead it into a mud, seal and age the mud in the dark, and then extrude it into a semi-finished product;

[0011] (3) Dry and calcine the semi-finished product to obtain the activated carbon carrier.

[0012] As a preferred technical solution, the shape of the semi-finished product includes spherical, cylindrical, and clover-shaped.

[0013] As a preferred technical solution, the temperature of the aging is 0-25°C, and the time > 24h.

[0014] As a preferred technical solution, the temperature of the drying is 100-150°C, and the time is 1-3h.

[0015] As a preferred technical solution, the calcination is carried out in a nitrogen atmosphere, the calcination temperature is 500-600°C, and the calcination time is 3-5h.

[0016] The present invention preferably uses wood-based activated carbon powder and coconut shell activated carbon powder as the raw materials of the activated carbon carrier, and combines with the doping of bentonite, asphalt, methyl cellulose, and polyvinyl alcohol powder to ensure the forming effect, obtain a high-strength catalyst carrier, and increase the loading amount of the active metal. In particular, controlling the mass ratio of bentonite in the activated carbon carrier ensures that the prepared activated carbon carrier has a higher specific surface area and better pore structure, providing more active sites for the subsequent loading of the active metal.

[0017] On the third aspect, the present invention provides an application of the activated carbon carrier, which is applied to the preparation of a hydrogenation catalyst. The preparation raw materials of the hydrogenation catalyst at least include: activated carbon carrier, nickel salt, doped metal salt, and deionized water.

[0018] As a preferred technical solution, the doped metal salt is a transition metal salt and / or a rare earth metal salt.

[0019] As a preferred technical solution, the doped metal salt is cerium nitrate hexahydrate and / or cobalt nitrate hexahydrate.

[0020] As a preferred technical solution, the nickel salt is nickel nitrate hexahydrate.

[0021] As a preferred technical solution, based on the mass of the activated carbon carrier, the addition amount of the doped metal salt is 50-100%, preferably 60-80 wt%.

[0022] As a preferred technical solution, based on the mass of the activated carbon carrier, the addition amount of the nickel salt is 5-40%, preferably 10-40 wt%.

[0023] As a preferred technical solution, the mass ratio of the activated carrier to deionized water is 1:(0.3-0.55), preferably 1:(0.3-0.5).

[0024] As a preferred technical solution, the preparation method of the hydrogenation catalyst at least includes the following steps: cutting the activated carbon carrier into uniform small segments of 5-10 mm, stirring and mixing the nickel salt, doped metal salt, and deionized water to prepare a catalyst solution; uniformly dropping the catalyst solution onto the carrier, and obtaining a catalyst-impregnated carrier after stirring, drying the catalyst-impregnated carrier at 140-160 °C for 1-3 h, and then ramping up the temperature to 400-500 °C and calcining in a nitrogen atmosphere for 1.5-3 h to obtain the hydrogenation catalyst.

[0025] As a preferred technical solution, the rate of temperature ramping is 3-6 °C / min.

[0026] Furthermore, in the present invention, by selecting nickel oxide as the main catalytic active component and transition metals or rare earth metals as co-catalysts, the prepared activated carbon carrier is subjected to load modification, so that the obtained catalyst meets the requirements of the selective hydrogenation reaction of 1,3-butadiene. In particular, by controlling the doped metal salt to be cobalt oxide and / or cerium oxide, the activity and selectivity of the hydrogenation catalyst are effectively improved.

[0027] The hydrogenation catalyst provided by the present invention not only has high hydrogenation activity, but also has improved selectivity through doping modification of the catalyst, so that the retention rate of monoolefins is higher than that of Pd-based catalysts, and side reactions such as olefin polymerization are not likely to occur, and the anti-poisoning ability is stronger than that of Ni / Al2O3 catalysts. It can overcome the disadvantages of the above two catalysts and is the trend of subsequent hydrogenation reactions.

[0028] Beneficial effects

[0029] 1. By optimizing the catalyst carrier formulation system, the present invention improves the mechanical strength of the catalyst carrier, and then prepares a catalyst with high activity and high selectivity, which meets the requirements of the selective hydrogenation reaction of 1,3-butadiene and has broad application prospects.

[0030] 2. The present invention preferably uses wood activated carbon powder and coconut shell activated carbon powder as the raw materials of the activated carbon carrier, and combines with the doping of bentonite, asphalt, methyl cellulose, and polyvinyl alcohol powder to ensure the forming effect, obtain a catalyst carrier with high strength, and increase the loading amount of active metal.

[0031] 3. The present invention controls the mass ratio of bentonite in the activated carbon carrier to ensure that the prepared activated carbon carrier has a higher specific surface area and better pore structure, providing more active sites for the subsequent loading of active metal.

[0032] 4. The present invention uses nickel oxide as the main catalytic active component and transition metal or rare earth metal as the promoter to perform loading modification on the prepared activated carbon carrier, so that the obtained catalyst meets the selective hydrogenation reaction requirements of 1,3-butadiene. In particular, controlling the doped metal salt to be cobalt oxide and / or cerium oxide effectively improves the activity and selectivity of the hydrogenation catalyst.

[0033] 5. The hydrogenation catalyst provided by the present invention not only has high hydrogenation activity, but also has improved selectivity through doping modification of the catalyst, making the monoolefin retention rate higher than that of the Pd-based catalyst, and is not prone to side reactions such as olefin polymerization. The anti-poisoning ability is stronger than that of the Ni / Al l2 O3 catalyst, and can overcome the disadvantages of the above two catalysts, which is the trend of subsequent hydrogenation reactions. Detailed implementation mode

[0034] Example 1

[0035] On the one hand, Example 1 of the present invention provides an activated carbon carrier. Calculated by weight, the preparation raw materials include: 937.67 parts of activated carbon powder, 103.02 parts of bentonite, 50 parts of asphalt, 30 parts of methyl cellulose, 20 parts of polyvinyl alcohol powder, and 500 parts of deionized water.

[0036] The activated carbon powder is wood activated carbon powder, with the product brand of 1000 iodine value 200-mesh wood activated carbon, sourced from Fujian Xinsen Carbon Industry Co., Ltd.

[0037] On the other hand, Example 1 of the present invention provides a preparation method of an activated carbon carrier, including the following steps:

[0038] (1) Add the activated carbon powder, bentonite, asphalt, methyl cellulose, and polyvinyl alcohol powder into a kneader to obtain a mixed powder;

[0039] (2) Add deionized water to the mixed powder, knead it into a mud, seal the mud with plastic wrap, age it in the dark to obtain the aged mud, put the aged mud into a screw-type extruding machine, and use a Φ2.5mm three-leaf mold to extrude and form to obtain a semi-finished product;

[0040] (3) After drying and roasting the semi-finished product, the activated carbon carrier is obtained.

[0041] The shape of the semi-finished product is clover-shaped.

[0042] The aging temperature is 0 - 25°C and the time is 24 h.

[0043] The drying temperature is 120°C and the time is 2 h.

[0044] The roasting is carried out in a nitrogen atmosphere, the roasting temperature is 550°C, and the roasting time is 4 h.

[0045] The third aspect of Example 1 of the present invention provides an application of an activated carbon carrier in the preparation of a hydrogenation catalyst. By weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 77.81 parts of nickel salt, 12.61 parts of doped metal salt, and 48.05 parts of deionized water.

[0046] The doped metal salt is cerium nitrate hexahydrate.

[0047] The nickel salt is nickel nitrate hexahydrate.

[0048] The preparation method of the hydrogenation catalyst includes the following steps: cutting the activated carbon carrier into uniform small segments of 5 mm, stirring and mixing the nickel salt, doped metal salt, and deionized water to prepare a catalyst solution; uniformly dropping the catalyst solution onto the carrier, and after stirring, obtaining a catalyst-impregnated carrier. The catalyst-impregnated carrier is dried at 150°C for 2 h, and the temperature is raised to 450°C by programmed heating. After roasting for 2 h, the hydrogenation catalyst is obtained.

[0049] Example 2

[0050] Example 2 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation manner is the same as that of Example 1, except that by weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 77.81 parts of nickel salt, 38.84 parts of doped metal salt, and 36.67 parts of deionized water, and the doped metal salt is replaced with cobalt nitrate hexahydrate.

[0051] Example 3

[0052] Example 3 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation manner is the same as that of Example 1, except that the wood-based activated carbon powder is replaced with coconut shell activated carbon powder, and the product brand is 1000 iodine value 200-mesh coconut shell activated carbon, which is sourced from Fujian Xinsen Carbon Co., Ltd.

[0053] Example 4

[0054] Example 4 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation manner is the same as that of Example 1, except that the wood activated carbon powder is replaced with coconut shell activated carbon powder. The product brand is coconut shell activated carbon with an iodine value of 1000 and 200 mesh, sourced from Fujian Xinsen Carbon Industry Co., Ltd. By weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 77.81 parts of nickel salt, 32.03 parts of doped metal salt, and 36.67 parts of deionized water. The doped metal salt is replaced with 12.61 parts of cerium nitrate hexahydrate + 19.42 parts of cobalt nitrate hexahydrate.

[0055] Example 5

[0056] Example 5 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation manner is the same as that of Example 1, except that the wood activated carbon powder is replaced with coconut shell activated carbon powder. The product brand is coconut shell activated carbon with an iodine value of 1000 and 200 mesh, sourced from Fujian Xinsen Carbon Industry Co., Ltd. By weight, the raw materials for preparing the activated carbon carrier include: 833.33 parts of activated carbon powder, 206.02 parts of bentonite, 50 parts of asphalt, 30 parts of methyl cellulose, 20 parts of polyvinyl alcohol powder, and 500 parts of deionized water.

[0057] Comparative Example 1

[0058] Comparative Example 1 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation manner is the same as that of Example 1, except that by weight, the raw materials for preparing the activated carbon carrier include: 729.17 parts of activated carbon powder, 306.02 parts of bentonite, 50 parts of asphalt, 30 parts of sesbania powder, 20 parts of polyvinyl alcohol powder, and 475 parts of deionized water. By weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 77.81 parts of nickel salt, 32.03 parts of doped metal salt, and 36.67 parts of deionized water. The doped metal salt is replaced with 12.61 parts of cerium nitrate hexahydrate + 19.42 parts of cobalt nitrate hexahydrate.

[0059] Comparative Example 2

[0060] Comparative Example 2 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation manner is the same as that of Example 1, except that by weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 77.81 parts of nickel salt, and 51.02 parts of deionized water.

[0061] Comparative Example 3

[0062] Comparative Example 3 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation is the same as that of Example 1, except that, by weight, the raw materials for preparing the activated carbon carrier include: 1041.67 parts of activated carbon powder, 50 parts of asphalt, 30 parts of sesbania powder, 20 parts of polyvinyl alcohol powder, and 525 parts of deionized water. By weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 77.81 parts of nickel salt, and 51.02 parts of deionized water.

[0063] Comparative Example 4

[0064] Comparative Example 4 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation is the same as that of Example 1, except that, by weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 38.91 parts of nickel salt, and 65.54 parts of deionized water.

[0065] Comparative Example 5

[0066] Comparative Example 5 of the present invention provides an activated carbon carrier, its preparation method and application. The specific implementation is the same as that of Example 1, except that, by weight, the raw materials for preparing the hydrogenation catalyst include: 100 parts of activated carbon carrier, 116.73 parts of nickel salt, and 36.62 parts of deionized water.

[0067] Performance test method

[0068] 1. The specific surface area and pore volume of the hydrogenation catalysts provided in the examples and comparative examples were tested, and the test results are shown in Table 1.

[0069] Table 1

[0070]

[0071]

[0072] 2. A fixed-bed reactor was used to evaluate the hydrogenation catalysts prepared in the examples and comparative examples. The results are shown in Table 2. The evaluation method is as follows: The hydrogenation catalyst was placed in a fixed-bed reactor, first replaced with N2 until the oxygen content was less than 20 ppm, and then reduced with H2. The reduction temperature was 450 °C, and the space velocity of H2 was not less than 200 h -1 , for 5 h; the reduced catalyst was purged with cold H2 to 50 - 70 °C; finally, an excessive amount of dimethyl disulfide was introduced and fully sulfided to obtain a highly active sulfided catalyst.

[0073] Reaction conditions: pressure 2.0 MPa, temperature 45 °C;

[0074] Raw material composition (mass ratio): n-butane: 50%, 1,3-butadiene: 15%, n-butene: 35%;

[0075] Hydrogen / diolefin molar ratio: 2;

[0076] Volume hourly space velocity: 0.5 h -1 ;

[0077] Table 2

[0078]

[0079] It can be seen from the data in Table 2 that the hydrogenation catalysts provided in Examples 1-5 have a higher monoolefin retention rate and dimer formation amount compared to the hydrogenation catalysts provided in Comparative Examples 1-5, the content of diolefins in the product is low, and the strength of the catalyst is high.

Claims

1. An activated carbon carrier, characterized in that The preparation raw materials at least include: activated carbon powder, bentonite, asphalt, methyl cellulose, polyvinyl alcohol powder and deionized water.

2. The activated carbon carrier according to claim 1, characterized in that The activated carbon powder is wood activated carbon powder or coconut shell activated carbon powder.

3. The activated carbon carrier according to claim 1, characterized in that Based on the total weight of the activated carbon powder and the bentonite, the mass proportion of the bentonite is 10-25%.

4. A method for preparing an activated carbon carrier according to any one of claims 1 to 3, characterized in that: At least the following steps are included: (1) adding activated carbon powder, bentonite, asphalt, methyl cellulose, and polyvinyl alcohol powder into a container and mixing to obtain a mixed powder; (2) adding deionized water to the mixed powder, kneading the mixture into a slurry, sealing the slurry, aging it in the dark, and then extruding it into a semi-finished product; (3) The semi-finished product is dried and calcined to obtain the activated carbon carrier.

5. An application of an activated carbon carrier according to any one of claims 1 to 3, characterized in that: The invention is applied to the preparation of a hydrogenation catalyst, wherein the raw materials for preparing the hydrogenation catalyst at least include: an activated carbon carrier, a nickel salt, a doped metal salt, and deionized water.

6. The use of the activated carbon carrier according to claim 5, characterized in that: The doping metal salt is a transition metal salt and / or a rare earth metal salt.

7. The use of the activated carbon carrier according to claim 5, characterized in that: The added amount of the doped metal salt is 50-100% based on the mass of the activated carbon carrier.

8. The use of the activated carbon carrier according to claim 5, characterized in that: The amount of the nickel salt added is 5-40% based on the mass of the activated carbon carrier.

9. The use of the activated carbon carrier according to claim 5, characterized in that: The mass ratio of the active carrier to deionized water is 1:(0.3-0.55).

10. The use of the activated carbon carrier according to claim 5, characterized in that: The method for preparing the hydrogenation catalyst comprises at least The method comprises the following steps: cutting an activated carbon carrier into uniform small segments of 5-10 mm, stirring and mixing nickel salt, doped metal salt and deionized water to prepare a catalyst solution; uniformly dropping the catalyst solution on the carrier, stirring to obtain a catalyst impregnated carrier, drying the catalyst impregnated carrier at 140-160° C. for 1-3 h, program-raising the temperature to 400-500° C., and calcining in a nitrogen atmosphere for 1.5-3 h to obtain a hydrogenation catalyst.

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