Redispersion of agglomerated noble metals on zeolite catalysts

摘要

A process is described for rejuvenation of a deactivated highly siliceous noble metal-containing zeolite catalyst having a framework silica to alumina ratio of at least about 20 which contains agglomerated noble metal in its deactivated state. The process comprises redispersing the noble metals associated with the deactivated catalyst by contacting the catalyst with a stream of inert gas containing molecular chlorine, water and optionally, oxygen, a temperatures ranging from about 150 DEG to about 450 DEG C., a partial pressure of chlorine of from about 6 to about 15 Torr and a ratio of partial pressure of water to partial pressure of chlorine of from about 0.01 to about 2 for a period of time sufficient to achieve redispersion; purging said catalyst with an inert gas; and reducing said purged catalyst in a stream of hydrogen at a temperature ranging from about 140 DEG C. to 550 DEG C.