METHOD TO RECOVER FLUIDITY OF FLUIDIZED BED CATALYST FOR PRODUCTION OF PHTHALIC ANHYDRIDE

摘要

PROBLEM TO BE SOLVED: To effectively recover the fluid performance which is important for a fluidized bed catalyst for the production of phthalic anhydride when the fluid performance of the catalyst decreases, by draining a part of the catalyst from a fluidized bed reactor, pulverizing the catalyst, controlling the particle size of the pulverized catalyst and then supplying the catalyst again to the reactor. ;SOLUTION: In a fluidized bed catalyst used for the production of phthalic anhydride, such problems occur that the active component which impregnates the catalyst bleeds out on the outer surfaces of catalyst particles and the component causes modification with time to increase its viscosity and causes aggregation of the catalyst or decrease in the fluid performance. In this case, the fluid performance is recovered by draining a part of the catalyst from the fluidizing bed reactor, pulverizing the catalyst, and then supplying the pulverized catalyst having 15μm particle size again into the reactor. In this method, the average particle size of the fluidizing bed catalyst before pulverization is preferably ≥30μm. The amt. of the pulverized catalyst to be supplied again to the reactor is preferably controlled to ≥0.1wt.% of the whole amt. of the catalyst in the reactor, and more preferably to a range from 0.1 to 25wt.%.;COPYRIGHT: (C)1997,JPO