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CN-121819800-B - Preparation method of high-bulk-ratio bimodal Kong Chi spherical alumina carrier

CN121819800BCN 121819800 BCN121819800 BCN 121819800BCN-121819800-B

Abstract

The application relates to the technical field of catalyst carriers, and particularly discloses a preparation method of a high-bulk-ratio bimodal Kong Chi spherical alumina carrier. The preparation method of the high-stacking-ratio bimodal Kong Chi spherical alumina carrier comprises the following steps of taking mesoporous pseudo-boehmite, macroporous pseudo-boehmite, a composite forming auxiliary agent, a soft template pore-expanding agent and a hard template pore-expanding agent as raw materials, dry-mixing for 10-20min under the vacuum degree of-0.06 to-0.08 MPa, adding a peptizing agent and deionized water, stirring and kneading to obtain a paste, extruding the paste, granulating, rounding, drying and roasting to obtain the alumina carrier. The preparation method of the application obtains the tooth-ball type alumina carrier with Gao Duibi and double-peak holes.

Inventors

  • GUO XIAOCHEN
  • HE YUQING
  • YANG FAN
  • GUO RUOBING

Assignees

  • 山西炬华新材料科技有限公司

Dates

Publication Date
20260508
Application Date
20260316

Claims (10)

  1. 1. The preparation method of the high-bulk-ratio bimodal Kong Chi spherical alumina carrier is characterized by comprising the following steps of: S1, taking 60-70 parts by weight of mesoporous pseudo-boehmite, 30-40 parts by weight of macroporous pseudo-boehmite, 3-5 parts by weight of composite forming auxiliary agent, 1-2 parts by weight of soft template pore-expanding agent and 1-2 parts by weight of hard template pore-expanding agent as raw materials, dry-mixing for 10-20min under the vacuum degree of-0.06 to-0.08 MPa, adding 1-2 parts by weight of peptizing agent and 60-70 parts by weight of deionized water, stirring and kneading to obtain paste, wherein the composite forming auxiliary agent comprises modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000, wherein the modified coated sesbania powder is obtained by spraying coating liquid on the surface of the sesbania powder, drying, and the preparation method of the coating liquid comprises the steps of adding polyvinyl alcohol or hydroxypropyl methylcellulose into the deionized water, then adding nano boehmite or pseudo-boehmite sol, adjusting the pH to 3.5-4.5, and stirring to obtain the coating liquid; s2, extruding and granulating the paste under the conditions of extrusion frequency of 15-30Hz and granulating clearance of 0.2-0.5mm, and then rounding for 10-20min at 40-60 ℃ to obtain a toothed spherical carrier; S3, drying the toothed spherical carrier for 3-5 hours at 60-80 ℃ and then drying the toothed spherical carrier for 2-4 hours at 110-130 ℃ to obtain a dried carrier, performing gradient roasting on the dried carrier sequentially through a low-temperature auxiliary removing section, a medium Wen Kuokong crystallization section and a high-temperature sintering section, and naturally cooling to room temperature to obtain the high-stacking-ratio double-peak Kong Chi spherical alumina carrier, wherein the low-temperature auxiliary removing section is 200-400 ℃, the heating rate is 2-3 ℃ per minute, the heat preservation is 1.5-2.5 hours, the medium Wen Kuokong crystallization section is 400-600 ℃, the heating rate is 3-4 ℃ per minute, the heat preservation is 1-2 hours, and the high-temperature sintering section is 800-900 ℃, the heating rate is 4-5 ℃ per minute, and the heat preservation is 2-3 hours.
  2. 2. The preparation method of the high-bulk-ratio bimodal Kong Chi spherical alumina carrier according to claim 1 is characterized in that the preparation method of the composite forming additive comprises the steps of taking modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000 according to a weight ratio of 3:2:1, adding deionized water, stirring, adding p-toluenesulfonic acid, heating to 70-80 ℃, carrying out heat preservation reaction for 2-3h, cooling to room temperature, vacuum drying, crushing and sieving to obtain the composite forming additive; The addition amount of the deionized water is 10% -15% of the total mass of the modified coated sesbania powder, the soluble starch and the polyethylene glycol PEG-4000; the addition amount of the p-toluenesulfonic acid is 0.5-1% of the total mass of the modified coated sesbania powder, the soluble starch and the polyethylene glycol PEG-4000.
  3. 3. The preparation method of the high-bulk-ratio bimodal Kong Chi spherical alumina carrier according to claim 2 is characterized in that the preparation method of the composite forming additive comprises the steps of taking modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000 according to a weight ratio of 3:2:1, adding deionized water and ascorbic acid, stirring, adding p-toluenesulfonic acid, heating to 70-80 ℃, carrying out heat preservation reaction for 2-3h, cooling to room temperature, vacuum drying, crushing and sieving to obtain the composite forming additive; The addition amount of the deionized water is 10% -15% of the total mass of the modified coated sesbania powder, the soluble starch and the polyethylene glycol PEG-4000; The addition amount of the p-toluenesulfonic acid is 0.5-1% of the total mass of the modified coated sesbania powder, the soluble starch and the polyethylene glycol PEG-4000; The addition amount of the ascorbic acid is 0.1-0.3% of the total mass of the modified coated sesbania powder, the soluble starch and the polyethylene glycol PEG-4000.
  4. 4. The preparation method of the high-bulk-ratio bimodal Kong Chi spherical alumina carrier according to claim 3 is characterized in that the preparation method of the composite forming additive comprises the steps of taking modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000 according to a weight ratio of 3:2:1, adding deionized water and ascorbic acid, stirring, adding p-toluenesulfonic acid and a silane coupling agent KH-550, heating to 70-80 ℃, carrying out heat preservation reaction for 2-3h, cooling to room temperature, carrying out vacuum drying, crushing and sieving to obtain the composite forming additive; The addition amount of deionized water is 10% -15% of the total mass of modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000, the addition amount of p-toluenesulfonic acid is 0.5% -1% of the total mass of modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000, the addition amount of ascorbic acid is 0.1% -0.3% of the total mass of modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000, and the addition amount of silane coupling agent KH-550 is 0.2% -0.4% of the total mass of modified coated sesbania powder, soluble starch and polyethylene glycol PEG-4000.
  5. 5. The method for preparing the high bulk ratio bimodal Kong Chi spherical alumina carrier according to claim 1, wherein in S1, the raw materials are 60-70 parts by weight of mesoporous pseudo-boehmite, 30-40 parts by weight of macroporous pseudo-boehmite, 3-5 parts by weight of composite forming auxiliary agent, 1-2 parts by weight of soft template pore-expanding agent, 1-2 parts by weight of hard template pore-expanding agent and 0.1-0.3 part by weight of nano silicon dioxide.
  6. 6. The method for preparing a high bulk ratio bimodal Kong Chi spherical alumina carrier according to claim 1, wherein in S1, the soft template pore-expanding agent is P123 or cetyltrimethylammonium bromide.
  7. 7. The method for preparing a high bulk ratio bimodal Kong Chi spherical alumina carrier according to claim 1, wherein in S1, the hard template pore-expanding agent is nano carbon microsphere, and the particle size of the nano carbon microsphere is 50-80nm.
  8. 8. The preparation method of the high bulk ratio bimodal Kong Chi spherical alumina carrier according to claim 1, wherein in S1, the pore volume of the mesoporous pseudo-boehmite is 0.7-0.9mL/g, the specific surface area is 280-320m 2 /g, and the pore volume of the macroporous pseudo-boehmite is 1.1-1.3mL/g, and the specific surface area is 200-240m 2 /g.
  9. 9. The method for preparing the high bulk ratio bimodal Kong Chi spherical alumina carrier according to claim 1, wherein in S1, the peptizing agent is a dilute nitric acid solution with mass concentration of 3% -5%.
  10. 10. The high-bulk-ratio bimodal Kong Chi spherical alumina carrier is characterized in that the carrier is prepared by the preparation method of the high-bulk-ratio bimodal Kong Chi spherical alumina carrier according to any one of claims 1 to 9.

Description

Preparation method of high-bulk-ratio bimodal Kong Chi spherical alumina carrier Technical Field The application relates to the technical field of catalyst carriers, in particular to a preparation method of a high-bulk-ratio bimodal Kong Chi spherical alumina carrier. Background The alumina carrier has excellent specific surface area, pore structure controllability, mechanical strength and chemical stability, and is widely applied to the fields of petrochemical industry, environmental protection, catalytic reaction, adsorption separation and the like, particularly in the industrial processes of heavy oil hydrogenation, residual oil catalytic cracking, automobile exhaust purification and the like, and the morphology, pore structure and stacking property of the alumina carrier directly determine the activity, selectivity, mass transfer efficiency and service life of the catalyst. In industrial catalytic and adsorption applications, the bulk density (bulk ratio) of the support is one of the key performance indicators. The carrier with high pile ratio can effectively improve the loading of the carrier in the reactor, reduce the volume occupation of the reactor, and improve the total loading amount of active components in unit volume, thereby improving the reaction efficiency and the processing capacity and reducing the equipment investment and the operation cost of industrial production. Meanwhile, the pore structure design of the carrier directly influences the contact efficiency and the mass transfer resistance of reactants and active components, the alumina carrier with single pore size distribution is difficult to meet the requirements of mass transfer efficiency and active component loading, the microporous structure can provide a higher specific surface area to load the active components, but the mass transfer resistance is overlarge, so that the diffusion of macromolecular reactants (such as colloid and asphaltene in heavy oil) is not facilitated, and the macroporous structure can reduce the mass transfer resistance, but the specific surface area is greatly reduced, and the loading capacity and the dispersibility of the active components are reduced. Therefore, the alumina carrier with the mesoporous and macroporous bimodal pore structures becomes a research hot spot, the mesoporous part of the alumina carrier can provide sufficient specific surface area for active component loading, and the macroporous part can be used as a mass transfer channel to accelerate the diffusion of reactants and products and improve the comprehensive performance of the catalyst. In addition, the morphology of the support has an important effect on its packing properties, bed pressure drop and fluid distribution. The shapes of alumina carriers commonly used in industry at present mainly comprise spherical shapes, cylindrical shapes, clover shapes and the like, wherein the spherical carriers have the advantages of good fluidity and uniform filling, but have the problems of lower stacking ratio caused by smaller outer surface area and too high bed void ratio, and the irregular carriers such as the clover shapes and the like can improve the specific surface area and the bed void ratio, but have the defects of poor fluidity, uneven filling, too large bed pressure drop, are easy to cause the problems of local overheating, coking and the like in a reactor, and influence the service life of a catalyst. The toothed spherical carrier is used as a novel special-shaped spherical carrier, has spherical appearance, is provided with toothed protrusions on the surface, has the advantages of good fluidity, uniform filling, large specific surface area of the special-shaped carrier and high mass transfer efficiency, has a toothed structure on the surface, can increase the outer surface area, optimize fluid distribution, reduce pressure drop of a bed layer, and simultaneously improves the loading uniformity of active components, and has obvious application advantages in the scenes of heavy oil hydrogenation, macromolecular catalytic conversion and the like. In the prior art, as disclosed in the patent application with publication number CN117244539A, a preparation method of a bimodal pore alumina pentadentate sphere carrier comprises the following steps of (1) raw material pseudo-boehmite powder (pore volume of 0.8-1.0mL/g mesoporous powder and pore volume of 1.0-1.2mL/g macroporous powder), extrusion aid (composed of sesbania powder, cellulose and citric acid monohydrate), 5-15% hard template pore-enlarging agent dry-mixing for 5-15min, adding aqueous solution (80-110% of water) of 5-25% soft template pore-enlarging agent, and continuously stirring for 20-60min; adding water (50-70%) and acid (0-2%), kneading, extruding at 10-25Hz, die plate hole diameter of 3.0-7.0mm, cutter gap of 0.3-0.7mm, arc or trapezoid cutter, drying at 120deg.C for 2-4 hr, and calcining at 850-950 deg.C for 2-4 hr to obtain sesbania powder as shaping aid, wherein the p