The features of a novel high-severity FCC process (HS-FCC) in enhancing light olefins andgasoline production at high conversion are highlighted. The configuration of HS-FCC includes adowner-reactor system operating at high reaction temperatures, higher catalyst/oil ratios and shortcontact time. This configuration prevents back-mixing and suppresses thermal cracking reactionsthereby maximizing gasoline and light olefins. The performance of a downer-type reactor versus riserhas been studied in a pilot plant with a capacity of 0.2 b/d. At 80wt% conversion, the downer systemshowed 22% increase in the production of gasoline compared to the riser system. The production of C2-C4 light olefins in the downer was relatively high at 23wt% but lower than the riser due to gasolineover-cracking in the riser. Yields of dry gas, coke, and 1,3 butadiene in the downer reactor were muchlower compared to the riser reactor. The results confirmed reduced effects of thermal cracking andback-mixing in the downer system configuration.
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