Process for converting olefinic hydrocarbons using spent FCC catalyst

A fluid catalytic cracking process for cracking a fluid catalytic cracking feedstock and for upgrading a separate feedstock containing olefins selected from the group consisting of C.sub.2 to C.sub.8 olefins and including at least C.sub.2 and C.sub.3 olefins to increase the overall yield of C.sub.4 -C.sub.5 olefins and isoparaffins in the fluid catalytic cracking product comprising the steps of:

• a. charging a fluid catalytic cracking feedstock into the riser reactor of a fluid catalytic cracking process;
• b. charging regenerated fluid catalytic cracking catalyst into said riser reactor;
• c. reacting said fluid catalytic cracking feedstock in the presence of said regenerated catalyst in said riser reactor to produce a hydrocarbon effluent and spent catalyst;
• d. introducing said hydrocarbon effluent and said spent catalyst into the reactor/stripper of said fluid catalytic cracking process;
• e. separating said hydrocarbon effluent and said spent catalyst in said reactor/stripper;
• f. charging said separate feedstock containing said olefins to be upgraded to said reactor/stripper;
• g. reacting said olefins in the presence of said spent catalyst to oligomerize at least some of said olefins and produce an upgraded olefin product containing additional C.sub.4 and C.sub.5 olefins and isoparaffins;
• h. simultaneously stripping said spent catalyst at least in part with said separate feedstock;
• i. combining said separated hydrocarbon effluent and said upgraded olefin product to form a combined fluid catalytic product;
• and
• j. removing said spent catalyst from said reactor/stripper and regenerating said spent catalyst.