A NEW CATALYTIC CRACKING PROCESS TO MAXIMIZE REFINERY PROPYLENE

A novel high-severity FCC process that maximizes propylene production is under development by research teams in Saudi Arabia and Japan. The process has been proven in a 30-BPD demonstration plant at Saudi Aramco’s refinery, Saudi Arabia, and at a 500-BPD cold flow model at Nippon Oil Corporation, Japan. The HS–FCC process combines mechanical modifications to conventional FCC with changes in process variables and catalyst formulations. The process main operating features are a down-flow reactor system, high reaction temperature, short contact time, and high catalyst to oil ratio. Experimental runs were conducted in a downer- and riser-type pilot plants and a demonstration plant using various catalysts, additives and feed oils. The experimental results demonstrated the advantage of downer in suppressing back- mixing, thus increasing the yield of light olefins (ethylene, propylene, and butylenes) and reducing dry gas. Using paraffinic crude base VGO feed and proprietary USY FCC catalyst, propylene yield of 25 wt% (feed basis) and gasoline yield of 30 wt% were obtained under HS-FCC reaction conditions.