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CN-119425714-B - Forming method of strip-shaped carrier, preparation method of metal-loaded catalyst, catalyst and application of catalyst

CN119425714BCN 119425714 BCN119425714 BCN 119425714BCN-119425714-B

Abstract

The invention discloses a preparation method of a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production, which comprises a carrier preparation process and a carrier impregnation process, wherein the carrier preparation process comprises five units of raw material intensive mixing, rolling and briquetting, strip extrusion molding, airing and curing and high-temperature roasting, the raw material intensive mixing is operated by a roller-type intensive mixer containing a rotor, and the carrier impregnation process comprises five units of rotary drum impregnation, high-temperature drying, high-temperature roasting, rolling and granulating and sieving and removing powder. The invention has the advantages of good mixing effect of the dry powder raw material and the liquid raw material, less emission of nitrogen oxides, high carrier strength and longer service life of the catalyst.

Inventors

  • CHEN GONGZHE
  • SUN QIANHUI
  • DU ZEXUE
  • ZHANG YONGQIANG
  • LIU YI

Assignees

  • 中国石油化工股份有限公司
  • 中石化石油化工科学研究院有限公司

Dates

Publication Date
20260505
Application Date
20230801

Claims (19)

  1. 1. A preparation method of a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production comprises a carrier preparation process and a carrier impregnation process, and is characterized in that, The carrier preparation process comprises five units of strong mixing of raw materials, rolling and forming, strip extrusion molding, airing and curing and high-temperature roasting, wherein, The method comprises the steps of performing strong mixing of raw materials by using a roller type strong mixer with a rotor, wherein dry powder materials are subjected to strong mixing for 20-30 minutes in the roller type strong mixer under the conditions that the speed of the inner rotor of the roller is 80-120 r/min and the rotating speed of the roller is 60-100 r/min, then adding liquid materials through a liquid feed hole under the condition that the stirring speed is not changed, and then lifting the speed of the inner rotor of the roller to 300-400 r/min and the strong mixing time of the roller under the condition that the rotating speed of the roller is lifted to 100-150 r/min is 45-60 minutes; The grinding and blocking is to pour the powder obtained by the raw material strong mixing unit into a grinding machine for grinding, wherein the mass ratio of the weight of the grinding wheel to the powder is 1:1-2:1, the grinding speed is 100-150 r/min, and the grinding time is 40-60 minutes; The strip extrusion molding is to put the block materials obtained by rolling the block forming units into a screw type strip extruder to carry out strip extrusion molding to obtain wet strip materials, wherein the strip extrusion speed is 2-5 cm/s; The drying and curing step is to dry and cure the wet strip material obtained by the strip extrusion forming unit in a well-ventilated place to obtain a dry strip material, wherein the curing temperature is 20-50 ℃, and the curing time is 16-24 hours; the high-temperature roasting is to carry out high-temperature roasting on the dry strip materials obtained by the air-drying and curing unit in a continuous mesh belt kiln, wherein the stacking height of the materials on the mesh belt is 3-4 cm, the roasting temperature is 500-700 ℃, and the roasting time is 5-10 hours, so that strip-shaped carriers are obtained; the carrier impregnation process comprises five units of drum impregnation, high-temperature drying, high-temperature roasting, rolling granulation and sieving powder removal, wherein, The high-temperature roasting is to roast the carrier obtained by the high-temperature drying unit in the carrier impregnation process at a high temperature in a continuous mesh belt kiln to obtain the strip-shaped catalyst, wherein the stacking height of the carrier on the mesh belt is 3-4 cm, the roasting temperature is 500-800 ℃, and the roasting time is 4-8 hours.
  2. 2. The method according to claim 1, wherein the powder is agglomerated into a lump material having a size of 5cm to 15 cm after the completion of the rolling and agglomerating unit in the preparation of the carrier.
  3. 3. The method according to claim 1, wherein after the high-temperature roasting unit in the carrier preparation process, the average side pressure strength of the strip-shaped carrier is 120-180N/cm.
  4. 4. The method of claim 1, wherein the drum impregnation is performed by pouring the strip-shaped support into a batch drum and then pouring an aqueous impregnation solution of the metal-containing precursor into the drum for support impregnation.
  5. 5. The method of claim 4, wherein the metal is selected from one or more of chromium, molybdenum, tungsten, copper, gold, silver, manganese, rhenium, zirconium, hafnium, cobalt, rhodium, iridium, gallium, indium, thallium, lanthanum, and cerium.
  6. 6. The method of claim 4, wherein the metal precursor is one or more of a metal nitrate, a metal acid ammonium salt, and a metal carboxylate.
  7. 7. The method of claim 4, wherein the metal precursor is one or more of copper nitrate trihydrate, lanthanum nitrate hexahydrate, ammonium tungstate pentahydrate, ammonium molybdate tetrahydrate, chromium nitrate nonahydrate, cobalt nitrate hexahydrate, zirconyl nitrate dihydrate, manganese nitrate, ammonium chloroaurate trihydrate, silver nitrate, ammonium perrhenate, ammonium tetrabutyl hafnate tetrachloride, rhodium caproate, ammonium chloroiridium nitrate hexahydrate, gallium nitrate, indium nitrate tetrahydrate, thallium nitrate trihydrate, ammonium ceric nitrate dihydrate.
  8. 8. The method according to claim 4, wherein the mass ratio of the impregnating aqueous solution to the bar carrier is 1:1-1.4:1, the impregnating vacuum degree is 0.06-0.10 MPa, the impregnating temperature is 30-50 ℃, the impregnating time is 30-50 minutes, and the rotating speed of the drum is 2-4 r/min.
  9. 9. The method according to claim 4, wherein the impregnating solution is completely evaporated by introducing steam into the drum jacket at a temperature of 90-120 ℃ for 1-2 hours while maintaining the vacuum degree and the rotation speed of the drum after the completion of the impregnation.
  10. 10. The method according to claim 1, wherein the high-temperature drying in the carrier impregnation process is to dry the carrier obtained by the drum impregnation unit in a drying oven at a drying temperature of 100-120 ℃ for 4-6 hours.
  11. 11. The method according to claim 1, wherein the rolling dicing is to dice a bar-shaped catalyst obtained by a high-temperature roasting unit in the carrier impregnation process in a roll cutter, and the rotation speed of the roll cutter is 100-200 r/min.
  12. 12. The method of claim 1, wherein the sieving to remove powder during the impregnation of the support is to remove crushed, pulverized catalyst in a sieving machine from the catalyst obtained by the rolling granulation unit.
  13. 13. The method according to claim 12, wherein in the sieving and powder removing unit of the carrier impregnation process, the pore size of a sieve of a sieving machine is not higher than the diameter of the carrier, the proportion of catalyst crushing and pulverization is 2% -8%, and the average lateral pressure strength of the catalyst is 120-180N/cm.
  14. 14. A molding method of a carrier in industrial production is characterized by comprising five units of strong mixing of raw materials, rolling and forming, extrusion molding, airing and curing and high-temperature roasting, wherein, The method comprises the steps of performing intensive mixing of raw materials by using a roller-type intensive mixer with a rotor, namely, performing intensive mixing on dry powder materials in the roller-type intensive mixer, wherein the speed of the inner rotor of the roller is 80-120 r/min, the intensive mixing time is 20-30 min under the condition that the rotating speed of the roller is 60-100 r/min, then adding liquid materials through a liquid feed hole under the condition that the stirring speed is not changed, and then, increasing the speed of the inner rotor of the roller to 300-400 r/min, wherein the intensive mixing time is 45-60 min under the condition that the rotating speed of the roller is increased to 100-150 r/min; the grinding and blocking step is to pour the powder obtained by the raw material strong mixing unit into a grinding machine for grinding, wherein the mass ratio of the weight of the grinding wheel to the powder is 1:1-2:1, the grinding speed is 100-150 r/min, and the grinding time is 40-60 minutes; the extrusion molding is to put the block materials obtained by rolling the block forming units into a screw extruder to perform extrusion molding to obtain wet strip materials, wherein the extrusion speed is 2-5 cm/s; The drying and curing step is to dry and cure the wet strip material obtained by the strip extrusion forming unit in a well-ventilated place to obtain a dry strip material, wherein the curing temperature is 20-50 ℃, and the curing time is 16-24 hours; And the high-temperature roasting is to carry out high-temperature roasting on the dry strip materials obtained by the air-drying and curing unit in a continuous mesh belt kiln, wherein the stacking height of the materials on the mesh belt is 3-4 cm, the roasting temperature is 500-700 ℃, and the roasting time is 5-10 hours, so that the strip-shaped carrier is obtained.
  15. 15. The method of forming a carrier according to claim 14, wherein after the completion of the rolling and agglomerating unit, the powder is agglomerated into a lump of 5 to 15 cm in size.
  16. 16. The hydrogen peroxide decomposition catalyst obtained by the production method according to any one of claims 1 to 13.
  17. 17. A method for decomposing hydrogen peroxide in an aqueous methanol solution, characterized in that the hydrogen peroxide decomposition catalyst according to claim 16 is used.
  18. 18. The method according to claim 17, wherein the mass fraction of hydrogen peroxide in the aqueous methanol solution is 0.02-1.0%.
  19. 19. The method according to claim 18, wherein the method is carried out in a fixed bed reactor, the feeding mass space velocity of the aqueous methanol solution is 1-10 h -1 , and the reaction temperature is 20-100 ℃.

Description

Forming method of strip-shaped carrier, preparation method of metal-loaded catalyst, catalyst and application of catalyst Technical Field The present invention relates to a method for molding a carrier, a method for preparing a catalyst, a catalyst and applications thereof, and more particularly, to a method for molding a bar-shaped carrier, a method for preparing a metal-supported bar-shaped hydrogen peroxide decomposition catalyst, the obtained catalyst and applications thereof in hydrogen peroxide decomposition. Background Hydrogen peroxide is now being used in various industries for bleaching, for example in the paper and textile fields, to obtain pulp and fibers with satisfactory and stable whiteness, in the electronic industry for cleaning silicon wafers and etching circuit boards, in the food industry for corrosion protection, disinfection, aseptic packaging, etc., in the environmental protection field for treating waste water containing organic matters, greatly reducing the Chemical Oxygen Demand (COD) of the waste water, and meeting the requirements of waste water discharge. Hydrogen peroxide has excellent oxidation performance, the reduction product is water, and the hydrogen peroxide is nontoxic and harmless, does not introduce impurities into the system, and has remarkable advantages in environmental friendliness and economy compared with the traditional oxidant. Particularly, after titanium-silicon molecular sieve (TS-1) is developed and industrial production is realized, the titanium-silicon molecular sieve and hydrogen peroxide form a mild and efficient catalytic oxidation system, and the titanium-silicon molecular sieve and hydrogen peroxide have good activity and selectivity in hydroxylation of benzene and phenol, epoxidation of olefin, ammoximation of cyclohexanone and oxidation reaction of amine and saturated alkane. However, in the oxidation reaction process, the conversion rate of hydrogen peroxide is usually maintained between 97% and 99%, so that the hydrogen peroxide still remains in the reaction product with a mass fraction of 0.05% to 0.5%. The hydrogen peroxide and organic matters form organic peroxide which is easy to explode in the subsequent separation process, and the hydrogen peroxide can be decomposed to release oxygen, so that the safe and continuous operation of the device is influenced. It is therefore necessary from a safety point of view to catalytically decompose it using a hydrogen peroxide decomposition catalyst. The most common hydrogen peroxide decomposition catalyst is a metal oxide, with manganese oxides being the most common, for example CN110240203a discloses a method of preparing manganese oxide catalysts. However, metal oxide catalysts are used after being packed in industrial reactors such as fixed beds, and thus such catalysts need to be shaped to meet the packing requirements of fixed beds or other reactors. At present, there are few reports on the molding technology of metal oxide catalysts, and CN114471591a discloses a bar-shaped decomposition catalyst, but does not disclose a specific molding method. Disclosure of Invention The inventors have found that in the preparation of a wide variety of catalyst shapes, the shaping steps, shaping equipment and process routes have a significant impact on the strength and catalytic activity of the catalyst, and the preparation of shaped catalysts that can meet the loading requirements of industrial applications, such as industrial fixed beds, is a challenge. Aiming at hydrogen peroxide decomposition, the invention aims to provide a preparation method of a strip-shaped composite metal oxide hydrogen peroxide decomposition catalyst suitable for industrial production, and the catalyst prepared by the method has excellent lateral pressure strength, meets the filling requirement of an industrial fixed bed, and has good catalytic decomposition effect on low-concentration hydrogen peroxide at low reaction temperature when being applied to hydrogen peroxide decomposition reaction. Accordingly, in a first aspect, the present invention provides a process for the preparation of a hydrogen peroxide decomposition catalyst for a strip-shaped composite metal oxide suitable for industrial production, comprising a support preparation process and a support impregnation metal process, characterized in that, The carrier preparation process comprises five units of raw material intensive mixing, rolling and forming, extruding and forming, airing and curing and high-temperature roasting, wherein the raw material intensive mixing is operated by a roller type intensive mixer with a rotor; the carrier impregnation process comprises five units of drum impregnation, high-temperature drying, high-temperature roasting, rolling granulation and sieving powder removal. In the preparation process of the carrier, the raw materials are intensively mixed in a drum-type intensive mixer, the intensive mixing time is 20-30 minutes under the condition that