Extending catalyst life by treating with phosphorus and/or steam

摘要

There is disclosed a method for decreasing catalyst coking and extending the usable catalyst life by pre-treatment of the catalyst with steam and/or a phosphorus-containing compound. Catalysts benefiting from such pre-treatment comprise crystalline zeolites characterized by a silica to alumina mole ratio of at least 12 and a constraint index, as herein defined, within the approximate range of 1 to 12.