Catalytic cracking processes for the catalytic cracking of naphtha again in order to increase the yield of light olefins

摘要

A process for increasing the yield of C.sub.3 and C.sub.4 olefins by injecting light cat naphtha together with steam into an upstream reaction zone of a FCC riser reactor. The products of the upstream reaction zone are conducted to a downstream reaction zone and combined with fresh feed in the downstream reaction zone.