Benzoic anhydride catalyst and preparation method thereof

Abstract

The invention relates to a catalyst that is used in the catalytic oxidation reaction between raw materials of ortho-xylene and / or naphthalin and gas phase that contains molecular oxygen for producing phthalic anhydride, as well as a preparation method of the catalyst. The catalyst comprises an inert imperforated carrier material and a catalytic active substance layer that is coated on the carrier and contains vanadic oxide, diantimony trioxide, titanium dioxide and a cementing agent, etc. In a preparation process of the catalyst, serum is firstly prepared, viscosity of the catalytic active substance serum is controlled, the carrier is heated, the serum is sprayed onto the carrier in a barrate, and the carrier is dried by hot wind. The catalyst is used for the field of chemical industry.

Description

technical field [0001] The invention relates to a phthalic anhydride catalyst and a preparation method thereof, in particular to a catalyst used for preparing phthalic anhydride by gas-phase catalytic oxidation reaction of ortho-xylene and naphthalene as raw materials and a gas containing molecular oxygen, and a preparation method of the catalyst. Background technique [0002] To produce phthalic anhydride by fixed-bed catalytic oxidation of o-xylene and / or naphthalene as raw material, V-Ti type supported catalyst is generally used, that is, V 2 o 5 and TiO 2 It is a catalytically active substance, and at least one compound selected from the group consisting of alkali metal, Sb, P, Nb, Ag, Zr, W, Au, Sn, Bi is added as a cocatalyst, and a non-porous inert carrier material is used. The catalyst is prepared by coating the catalytically active material on an inert, non-porous carrier in the form of a thin layer, usually 0.02 to 2 mm. [0003] The catalyst used in the fixed-b...

AI Technical Summary

Problems solved by technology

When the catalyst active material forms an active material coating on the surface of the carrier, due to the influence of water vapor evaporation, the catalyst active material coating is loose, the strength is poor, the surface of the catalyst is rough, and the fine active material powder is easy to fall off

[0013] In the above-mentioned catalyst preparation method, due to the above problems, the loss of active substances in the preparation is large, which affects the production cost of the catalyst; due to the preparation of the catalyst at high temperature, the open equipment, poor working environment, and a lot of dust affect the environment and have a negative impact on the environment. The operator is very poisonous; the appearance of the catalyst is poor, and the surface active substances are easy to fall off, which affects the pressure drop of the catalyst bed and causes the pressure drop of the catalyst bed to be unstable, which may lead to uneven feeding of raw gas during the reaction process

The performance of the catalyst cannot be brought into full play. The existing defects are mainly the poor stability of the catalyst. After repeated start-up and shutdown, the selectivity and activity of the catalyst will decline to varying degrees, and the product yield and product quality will decline.