Upgrading naphtha in a multiple riser fluid catalytic cracking operation employing a catalyst mixture

A process for producing gasoline comprising contacting a hydrocarbon feed having an initial boiling-point of at least 400.degree. F., a 50% boiling of at least 500.degree. F. and an end boiling point of at least 600.degree. F., in a first riser, with a two component catalyst under fluid catalytic cracking conditions wherein at least one component of the catalyst is stripped in a stripping unit to remove entrained hydrocarbons, and regenerated wherein the two component catalyst comprises a first catalyst component selected from the group consisting of an amorphous cracking catalyst and a large pore cracking catalyst, whereby a product comprising olefins and naphta is produced;

• introducing ethylene together with said two component catalyst to a second riser, for contacting ethylene with a second catalyst component which is a shape selective medium pore crystalline silicate zeolite to produce products heavier than ethylene and to increase the temperature of the catalyst to an optimum temperature for upgrading naphtha;
• and
• introducing to the second riser, downstream of the point of ethylene introduction, naphtha for contact with said catalyst at said optimum temperature and said naphtha is upgraded to gasoline product.