US Patent 7678342 Riser reactor for fluidized catalytic conversion

A riser reactor for fluidized catalytic conversion process consists of a prelift zone, a first reaction zone, a second reaction zone with enlarged diameter, an outlet zone with reduced diameter along coaxial direction form bottom to top, and the end of the outlet zone connects to a horizontal tube. The reactor is used for adjusting different operating conditions to process single or plural feedstock in each different reaction zone for producing the desired product.