| abstract |
A catalytic cracking catalyst mixture and process are disclosed. The mixture comprises (a) a cracking catalyst containing a matrix and a large pore molecular sieve and (b) separate additive catalysts comprising at least one of a shape selective paraffin cracking/isomerization zeolite and a shape selective aliphatic aromatization zeolite. An exemplary catalyst mixture comprises Dealuminized zeolite Y, optionally containing rare earth elements in an alumina-rich matrix, an additive catalyst of HZSM-5 in a matrix, and an additional additive catalyst of gallium ZSM-5 in a matrix. The alumina-rich matrix of the cracking catalyst acts as a sodium and metals sink. The large pore molecular sieve catalyst cracks large hydrocarbons to lighter paraffins and olefins. The shape selective paraffin cracking/isomerization component cracks/isomerizes the paraffins produced by the large pore molecular sieve. The shape selective aliphatic aromatization catalyst converts light paraffins and olefins into aromatics. A single shape selective zeolite, e.g., ZSM-5 with a controlled amount of an aromatization component such as gallium, may promote both paraffin cracking/isomerization and aromatization. The additive catalylsts have physical properties, e.g., size, shape, density and attrition resistance which are substantially the same as the cracking catalyst. |