Research and Development of a Fluidized Bed Catalyst for Production of Phthalic Anhydride and Commercialization Thereof (Part 1) Preparation of Silica-supported V_2O_5 Catalyst Having Good Attrition Resistance and Catalytic Properties

摘要

Kawasaki Steel Corp. has produced approximately 30,000 ton/or of phthalic anhydride from coal-tar naphthalene by catalytic oxidation over silica-supported V_2O_5 catalyst (Davison #906: V_2O_5-K_2SO_4-SO_3/SiO_2) in a fluidized bed reactor, since 1979. The performance of catalyst licensed by Badger Corp, however, was not quite suitable for fluidized bed process because of its physical properties, i.e., low attrition resistance, poor fluidization and uneven dispersion of active components in catalyst particles. The purpose of present study is to improve performance of the catalyst in the fluidized bed reactor. Previously, particles-defects were found with impregnating method of preparation using pulverized silica particles as support. Recently, a new spray-drying method of preparation was found, using sine silica sols of sizes from 5 to 12 nm in diameter, which eases to obtain micro-spherical catalyst having uniform quality and ideal operability. A commercial plant, using the said developed catalyst for oxidation of naphthalene, was found to be operating ideally with catalysts performing effectively.