VAPOR PHASE CATALYTIC OXIDATION OF N-BUTANE TO MALEIC ANHYDRIDE INCORPORATING IN SITU CATALYST CALCINATION / ACTIVATION

摘要

An improved process for selective vapor phase oxidation ofn-butane to maleic anhydride involving the use of a recirculatingsolids reactor having a reaction zone and a catalyst regenerationzone wherein n-butane is converted to maleic acid in the reactionzone by use of a vanadium/phosphorous oxide (V/P/O) catalyst inoxidized form and the reduced vanadium/phosphorous oxide catalystis regenerated by contact with oxygen in the regeneration zone.Replenishment of the inherent catalyst losses associated with thecatalyst recycling process is accomplished by adding to the catalystin the regeneration zone vanadium/phosphorous oxide catalystprecursor at a rate of addition that effectuates in situ calcinationand activation of the vanadium/phosphorous oxide catalyst precursorwhile simultaneously maintaining the desired operating temperatureof the n-butane to maleic anhydride conversion reaction. Such aprocess is useful in maintaining the high operating capacity of thereactor over an extended period of time.