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CN-121988358-A - Heteropoly acid catalyst and preparation method and application thereof

CN121988358ACN 121988358 ACN121988358 ACN 121988358ACN-121988358-A

Abstract

The invention relates to the technical field of catalysts, and discloses a heteropolyacid catalyst, a preparation method and application thereof. The roundness of the heteropoly acid catalyst is more than or equal to 0 and less than or equal to 0.8, meanwhile, the relationship between the stacking density rho, the roundness P and the average radius R avg of the heteropoly acid catalyst is more than or equal to 0 and less than or equal to (2 multiplied by rho multiplied by P)/R avg and less than or equal to 0.95, the catalyst can be efficiently stacked and arranged in a reactor tube, so that the catalyst is more tightly arranged, channeling and back mixing of raw material gas among catalyst particles are effectively reduced, the utilization rate of methacrolein can be improved in the reaction of producing methacrylic acid by oxidizing methacrolein, and meanwhile, the occurrence of excessive reaction is reduced, so that the catalyst can simultaneously maintain higher methacrolein conversion rate and methacrylic acid selectivity. Meanwhile, the specific structure of the outer surface of the catalyst can ensure that the catalyst has good mechanical strength, reduce the cracking and breaking conditions and prolong the service life of the catalyst.

Inventors

  • LI ZEKANG
  • PAN SHIWEI
  • Yang taibao
  • LI QINGZHI
  • WANG BEN
  • MA MINGHONG
  • YI GUANGQUAN
  • LI ZUOJIN

Assignees

  • 万华化学集团股份有限公司

Dates

Publication Date
20260508
Application Date
20260104

Claims (10)

  1. 1. A heteropolyacid catalyst is characterized in that the roundness P of the heteropolyacid catalyst is 0<P to or less than 0.8; The relationship among the bulk density rho, the roundness P and the average radius R avg of the heteropoly acid catalyst is 0< (2 multiplied by rho multiplied by P)/R avg is less than or equal to 0.95; wherein, the unit of P is mm, the unit of ρ is g/mL, and the unit of R avg is mm.
  2. 2. The heteropolyacid catalyst according to claim 1, wherein the particle size of the heteropolyacid catalyst is 1.95mm to 2.20mm.
  3. 3. The heteropolyacid catalyst according to claim 1 or 2, comprising ceramic spheres and a coating layer coated on the outer surfaces of the ceramic spheres, wherein the coating layer comprises an active material, a structure aid and a morphology aid.
  4. 4. The heteropolyacid catalyst according to claim 3, wherein the active material has a chemical formula of Mo 12 P a V b Cu c As d X e O f , wherein 1≤a≤ 4,0.1≤b≤ 2.7,0.1≤c≤1, 0.1≤d≤1, 0≤e≤0.7, and f is the number of oxygen atoms required to satisfy the valence of each element; X is an auxiliary agent, wherein the auxiliary agent comprises at least one of antimony, tungsten, germanium, bismuth, iron, cobalt, magnesium, ruthenium, nickel, zinc and manganese; And/or the structure auxiliary agent comprises at least one of silicon carbide fiber, alumina fiber, mullite fiber, aluminum silicate fiber and silicon nitride fiber; And/or, the morphology aid comprises aluminum silicate fibers and metal oxides; Optionally, the metal oxide includes at least one of zirconia, tungsten oxide, copper oxide, molybdenum oxide, vanadium pentoxide, and cuprous oxide.
  5. 5. The heteropolyacid catalyst according to claim 4, wherein the content of the active material in the heteropolyacid catalyst is 25wt% to 60wt%; and/or, in the heteropolyacid catalyst, the content of the structural aid is 0.1wt% to 5wt%; And/or, in the heteropolyacid catalyst, the content of the morphology auxiliary agent is 0.1wt% to 5wt%; And/or, in the morphology auxiliary agent, the content of the metal oxide is 0.1wt% to 10wt%.
  6. 6. A process for the preparation of a heteropolyacid catalyst according to any one of claims 1 to 5, comprising the steps of: mixing and sintering the porcelain ball, the active material, the structure auxiliary agent and the morphology auxiliary agent to prepare the heteropolyacid catalyst.
  7. 7. The method for preparing a heteropolyacid catalyst according to claim 6, wherein the mass ratio of the active material, the structure aid and the morphology aid is 1:0.001-0.12:0.001-0.12; and/or the mass ratio of the porcelain ball to the active ingredient is 0.6-2.5:1; And/or the sintering temperature is 200-400 ℃, the time is 1-10 h, and the temperature rising rate is 0.2-2 ℃ per minute; And/or the preparation method of the active material comprises mixing molybdenum source, phosphorus source, vanadium source, copper source and arsenic source, and reacting to obtain the active material; Optionally, the molar ratio of the molybdenum element in the molybdenum source, the phosphorus element in the phosphorus source, the vanadium element in the vanadium source, the copper element in the copper source and the arsenic element in the arsenic source is 12:1-4:0.1-2.7:0.1-1:0.1-1; Optionally, adding an auxiliary agent when preparing the active material; Optionally, the auxiliary agent comprises at least one of an antimony source, a tungsten source, a germanium source, a bismuth source, an iron source, a cobalt source, a magnesium source, a ruthenium source, a nickel source, a zinc source and a manganese source; Optionally, the molar ratio of the molybdenum element in the molybdenum source to the metal element in the auxiliary agent is 12:0.1-0.7.
  8. 8. Use of the heteropoly acid catalyst according to any one of claims 1 to 5 or prepared by the preparation method according to claim 6 or 7 for catalyzing gasification oxidation of methacrolein to prepare methacrylic acid.
  9. 9. A method for producing methacrylic acid, comprising the steps of: In the presence of a catalyst and oxygen-containing gas, performing oxidation reaction on methacrolein to prepare methacrylic acid; The catalyst is the heteropolyacid catalyst according to claims 1-5 or prepared by the preparation method according to claim 6 or 7.
  10. 10. The method for producing methacrylic acid according to claim 9, wherein the reaction temperature is 240 ℃ to 370 ℃, the pressure is 0.01MPa to 0.15MPa, and the space velocity is 600h -1 -1300h -1 ; and/or the molar ratio of the methacrolein to the oxygen in the oxygen-containing gas is from 1:1 to 5.5.

Description

Heteropoly acid catalyst and preparation method and application thereof Technical Field The invention relates to the technical field of catalysts, in particular to a heteropolyacid catalyst and a preparation method and application thereof. Background Methacrylic acid is an important intermediate in organic chemical raw materials and polymers and is widely used for manufacturing coatings, insulating materials, adhesives and ion exchange resins, and besides, methyl methacrylate derived from the methacrylic acid is an important intermediate for producing organic glass. Compared with the acetone cyanohydrin method, the isobutene method can avoid the use of the virulent compound hydrocyanic acid, and can effectively avoid the generation of waste acid and the corrosion of equipment. The isobutene method is divided into two steps of reactions, namely, firstly, tert-butyl alcohol/isobutene is reacted to prepare methacrolein under the condition of Mo-Bi multi-metal oxide catalyst, and then, the methacrolein is generated by gas-phase catalytic oxidation of heteropoly acid (phosphomolybdic acid). However, methacrylic acid is easy to generate excessive oxidation to generate carbon oxide on the heteropoly acid catalyst, so that the conversion rate of methacrolein and the selectivity of methacrylic acid are lower, in addition, the surface strength of the phosphomolybdic acid catalyst is poorer, and the surface of the catalyst is cracked and broken due to mutual collision during production, transportation or use, so that dust is generated and the normal use of the catalyst is influenced. Therefore, how to develop a catalyst with high strength, high methacrolein conversion rate and high methacrylic acid selectivity is a technical problem to be solved in the art. Disclosure of Invention The invention provides a heteropoly acid catalyst to solve the problems of low strength, low methacrolein conversion rate and low methacrylic acid selectivity of the heteropoly acid catalyst in the prior art. In a first aspect, the present invention provides a heteropolyacid catalyst having a roundness P of 0<P≤0.8; The relationship among the bulk density rho, the roundness P and the average radius R avg of the heteropoly acid catalyst is 0< (2 multiplied by rho multiplied by P)/R avg is less than or equal to 0.95; wherein, the unit of P is mm, the unit of ρ is g/mL, and the unit of R avg is mm. In some alternative embodiments, the particle size of the heteropolyacid catalyst is from 1.95mm to 2.20mm. In some alternative embodiments, the heteropolyacid catalyst comprises ceramic spheres and a coating layer coated on the outer surfaces of the ceramic spheres, wherein the coating layer comprises an active material, a structure aid and a morphology aid. In some alternative embodiments, the active material has the chemical formula Mo 12PaVbCucAsdXeOf, wherein a≤a≤ 4,0.1≤b≤ 2.7,0.1≤c≤1, d≤1, e≤0.7, f is the number of oxygen atoms required to satisfy the valence of each element, and X is an auxiliary agent including at least one of antimony, tungsten, germanium, bismuth, iron, cobalt, magnesium, ruthenium, nickel, zinc, and manganese. In some alternative embodiments, the structural aid comprises at least one of silicon carbide fibers, alumina fibers, mullite fibers, aluminum silicate fibers, silicon nitride fibers. In some alternative embodiments, the topography assistance agent comprises aluminum silicate fibers and metal oxides. In some alternative embodiments, the metal oxide comprises at least one of zirconia, tungsten oxide, copper oxide, molybdenum oxide, vanadium pentoxide, and cuprous oxide. In some alternative embodiments, the content of the active material in the heteropolyacid catalyst is 25wt% to 60wt%. In some alternative embodiments, the content of the structure aid in the heteropolyacid catalyst is 0.1wt% to 5wt%. In some alternative embodiments, the morphology promoter is present in the heteropolyacid catalyst in an amount of 0.1wt% to 5wt%. In some alternative embodiments, the metal oxide is present in the topography assistance agent in an amount of 0.1wt% to 10wt%. In a second aspect, the present invention provides a method for preparing the heteropolyacid catalyst according to the first aspect, comprising the steps of: mixing and sintering the porcelain ball, the active material, the structure auxiliary agent and the morphology auxiliary agent to prepare the heteropolyacid catalyst. In some alternative embodiments, the mass ratio of the active material, the structural aid, and the morphology aid is from 1:0.001 to 0.12:0.001 to 0.12. In some alternative embodiments, the mass ratio of the porcelain ball to the active ingredient is 0.6-2.5:1. In some alternative embodiments, the sintering is performed at a temperature of 200 ℃ to 400 ℃ for a time of 1h to 10h and at a temperature increase rate of 0.2 ℃ per minute to 2 ℃ per minute. In some alternative embodiments, the active material is prepared by mixing and reacting a molybdenum