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CN-118125457-B - Prefluidizing agent, preparation method and application thereof

CN118125457BCN 118125457 BCN118125457 BCN 118125457BCN-118125457-B

Abstract

The invention relates to the technical field of caprolactam preparation processes, and discloses a prefluidizing agent, a preparation method and application thereof. The prefluidizing agent consists of a silicon dioxide matrix and optional impurity metal elements, wherein the content of the impurity metal elements is not higher than 3000ppm based on the total mass of the prefluidizing agent, the abrasion index of the prefluidizing agent is not higher than 12%/h, the BET specific surface area is 210-300cm 2 /g, and the bulk density is 0.7-1.1g/cm 3 . The prefluidizing agent provided by the invention has physical and chemical properties close to those of a true agent, is inert to the gas-phase Beckmann rearrangement reaction process of cyclohexanone oxime, can be used for examining blank experiments of fluidized bed processes, can obtain important basic data, such as correction of instruments, meters and equipment such as thermocouples, differential pressure meters and the like, and can replace the gas-phase rearrangement catalyst to obtain valuable data, such as the circulation state of a reaction-regeneration system catalyst.

Inventors

  • ZHANG HUATING
  • LI TUO
  • CHEN XIBO

Assignees

  • 岳阳凯达科技开发有限责任公司
  • 北京旭阳科技有限公司

Dates

Publication Date
20260505
Application Date
20230524

Claims (20)

  1. 1. A prefluidizing agent, characterized in that it consists of a silica matrix and optionally impurity metal elements, the content of which is not higher than 3000ppm, based on the total mass of the prefluidizing agent; The abrasion index of the pre-fluidization agent is not higher than 12 percent/h, the pore volume of the pre-fluidization agent is 0.5-1cm 3 /g, and the bulk density is 0.7-1.1g/cm 3 ; The preparation method of the prefluidizing agent comprises the following steps: (1) Mixing and pulping alkaline silica sol, an auxiliary agent and water to obtain mixed slurry; the auxiliary agent is at least one selected from n-octanol, isooctyl alcohol, polyvinyl alcohol, starch, glycerol and polyethylene glycol; wherein the viscosity of the mixed slurry is 28-60 mPa.s, and the particle size of the particles in the mixed slurry is smaller than or equal to 32 mu m, smaller than or equal to 20 mu m and smaller than or equal to 10 mu m, namely D100; (2) And carrying out spray forming and forming roasting on the mixed slurry.
  2. 2. The prefluidizing agent of claim 1, wherein the prefluidizing agent has a pore volume of 0.75-0.9cm 3 /g.
  3. 3. The prefluidizing agent according to claim 1 or 2, wherein the prefluidizing agent has a wear index of 4-10%/h; And/or the bulk density of the prefluidizing agent is 0.86-1g/cm 3 .
  4. 4. A prefluidizing agent according to claim 3, wherein the prefluidizing agent has a attrition index of 4-8%/h.
  5. 5. The prefluidizing agent according to claim 1 or 2, wherein the content of the impurity metal element is not more than 1500ppm based on the total mass of the prefluidizing agent.
  6. 6. A process for preparing a prefluidizing agent as claimed in any one of claims 1 to 5, which comprises: (1) Mixing and pulping alkaline silica sol, an auxiliary agent and water to obtain mixed slurry; the auxiliary agent is at least one selected from n-octanol, isooctyl alcohol, polyvinyl alcohol, starch, glycerol and polyethylene glycol; wherein the viscosity of the mixed slurry is 28-60 mPa.s, and the particle size of the particles in the mixed slurry is smaller than or equal to 32 mu m, smaller than or equal to 20 mu m and smaller than or equal to 10 mu m, namely D100; (2) And carrying out spray forming and forming roasting on the mixed slurry.
  7. 7. The preparation method according to claim 6, wherein the content of silica in the alkaline silica sol is 30 to 40wt%; and/or the pH of the alkaline silica sol is 9-11; and/or, the content of impurity metal elements in the alkaline silica sol is not higher than 1500ppm.
  8. 8. The preparation method according to claim 7, wherein the alkaline silica sol is an ammonium-type alkaline silica sol.
  9. 9. The process according to claim 6 or 7, wherein in the step (1), the mass ratio of the auxiliary agent to the alkaline silica sol in terms of SiO 2 is (0.01-0.1): 1.
  10. 10. The process according to claim 9, wherein in the step (1), the mass ratio of the auxiliary agent to the alkaline silica sol in terms of SiO 2 is (0.04-0.08): 1.
  11. 11. The production method according to claim 6 or 7, wherein the mixed slurry has a solid content of 20 to 60wt%.
  12. 12. The production method according to claim 6 or 7, wherein the auxiliary agent is at least one selected from starch, n-octanol and polyvinyl alcohol.
  13. 13. The method of claim 12, wherein the adjuvant comprises a first adjuvant and a second adjuvant, the first adjuvant is n-octanol, and the second adjuvant is starch and/or polyvinyl alcohol.
  14. 14. The preparation method according to claim 13, wherein the mass ratio of the first auxiliary agent to the second auxiliary agent is 0.001-0.1:1.
  15. 15. The production method according to claim 6 or 7, wherein the mixed slurry further comprises a pore volume adjuster.
  16. 16. The preparation method of claim 15, wherein the pore volume regulator is at least one selected from the group consisting of polyacrylamide, activated carbon, sesbania powder, cellulose, urea and sucrose.
  17. 17. The preparation method according to claim 15, wherein the mass ratio of the pore volume regulator to the alkaline silica sol calculated as SiO 2 is 0-0.05:1.
  18. 18. The production method according to claim 6 or 7, wherein the viscosity of the mixed slurry is 35 to 60 mPa-s; and/or the particle size of the particles in the mixed slurry is smaller than or equal to 20 mu m, smaller than or equal to 10 mu m and smaller than or equal to 5 mu m, namely D100.
  19. 19. Use of the prefluidizing agent according to any of claims 1-5 in a cyclohexanone oxime gas-phase beckmann rearrangement fluidized bed device.
  20. 20. Use according to claim 19, wherein the cyclohexanone oxime gas-phase beckmann rearrangement fluidized bed device comprises a reactor and a regenerator, and the method of using the prefluidizing agent in the cyclohexanone oxime gas-phase beckmann rearrangement fluidized bed device comprises that the prefluidizing agent is respectively put into the reactor and the regenerator for circulation at 350-400 ℃.

Description

Prefluidizing agent, preparation method and application thereof Technical Field The invention relates to the technical field of caprolactam preparation processes, in particular to a prefluidizing agent and a preparation method and application thereof. Background Epsilon-caprolactam is an important commodity chemical, mainly used for producing nylon 6 fibers and nylon 6 engineering plastics. The nylon 6 fiber is widely applied to industries such as textile, weaving, cord fabric, carpet yarn and the like, and the nylon 6 engineering plastic is widely applied to industries such as electronics, automobiles, ships, packaging films and the like. The caprolactam industry is closely related to civil life and plays an important role in national economy. The cyclohexanone oxime gas-phase Beckmann rearrangement reaction is a novel process for realizing the non-sulphuration of caprolactam, has the advantages of no carbon emission, no equipment corrosion, no environmental pollution and the like, and greatly simplifies the separation and purification of products, so that the non-sulphurated gas-phase Beckmann rearrangement reaction process is greatly focused by the industry personnel. The industrial production of caprolactam is carried out by adopting a new gas-phase Beckmann rearrangement fluidized bed process for the first time in 4 months of 2003 by Sumitomo chemical industry Co., ltd, the start-up is successful, and the capacity of an industrial production device reaches 5.5 ten thousand tons/year of caprolactam. They used a fluidized bed continuous reaction-regeneration new process, after which 4 months in 2006 the industrial plant was scaled up to 8 ten thousand tons/year caprolactam production. In the process mature FCC and MTO fluidized bed processes, a report of device cleaning and debugging by adopting a pre-fluidization agent exists, but compared with the two reaction processes, the cyclohexanone oxime gas-phase Beckmann rearrangement reaction belongs to strong exothermic and rapid reaction, has the characteristics of high reaction temperature, low reaction pressure and various side reaction types, therefore, in the existing fluidized bed process cold mold test, hollow glass beads, which are also called glass floating beads, are generally adopted, compared with the traditional solid glass beads (Geldart B particles), the particle density of the hollow glass beads used in the cold mold test is about 750kg/m 3, the bulk density is about 450kg/m 3, the bulk porosity is 0.4, the average particle size is about 90-100 mu m, the physical and chemical index deviation from a real gas-phase rearrangement catalyst is larger, and the abrasion index is not ideal. In this case, initial debugging, cleaning, etc. of the apparatus inevitably increases the risk of damaging the catalyst. In view of the relatively expensive molecular sieve catalyst used in the cyclohexanone oxime gas-phase beckmann rearrangement fluidized bed process, in order to avoid unnecessary losses, it is necessary to find a prefluidizing agent having physical properties close to those of the microsphere molecular sieve catalyst used in the cyclohexanone oxime gas-phase beckmann rearrangement fluidized bed process used in industrial plants. Disclosure of Invention The invention aims to obtain a prefluidizing agent with similar physical properties to a microsphere molecular sieve catalyst of a cyclohexanone oxime gas-phase Beckmann rearrangement fluidized bed process, and provides a prefluidizing agent, a preparation method and application thereof, the pre-fluidizer has similar particle distribution, abrasion index and bulk density with the microsphere molecular sieve catalyst used in the cyclohexanone oxime gas-phase Beckmann rearrangement fluidized bed process used in industrial devices, and has low cost. In order to achieve the above object, a first aspect of the present invention provides a prefluidizing agent composed of a silica matrix and optionally an impurity metal element, the impurity metal element being contained in an amount of not more than 3000ppm on an elemental basis based on the total mass of the prefluidizing agent; The abrasion index of the pre-fluidization agent is not higher than 12 percent/h, the BET specific surface area is 210-300cm 2/g, and the bulk density is 0.7-1.1g/cm 3. In a second aspect, the present invention provides a method for preparing the above-mentioned prefluidizing agent, the method comprising: (1) Mixing and pulping alkaline silica sol, an auxiliary agent and water to obtain mixed slurry; the auxiliary agent is an alcohol compound and/or an epoxy compound; wherein the viscosity of the mixed slurry is 28-60 mPa.s, and the particle size of the particles in the mixed slurry is smaller than or equal to 32 mu m, smaller than or equal to 20 mu m and smaller than or equal to 10 mu m, namely D100; (2) And carrying out spray forming and forming roasting on the mixed slurry. In a third aspect the invention provides the use of