Cat cracker gas plant process for increased olefins recovery

The invention relates to a new process for more efficient separation and recovery of light olefins such as ethylene and propylene from a fluid catalytic cracking unit. The new process invention for recovering olefins from a mixture of cracked hydrocarbons from a fluid catalytic cracker comprises the steps of: (a) providing a mixture of cracked hydrocarbons including methane, ethylene, ethane, propylene, propane, butylene, butane and heavier hydrocarbons such as naphtha produced in a fluid catalytic cracker; (b) separating said mixture into (i) a first stream comprising substantially all of said ethane, ethylene, and methane and a major portion of said propane and propylene and (ii) a second stream comprising a portion of said butylene and butane, and a major portion of said heavier hydrocarbons; and (c) processing said first stream to recover the ethylene and propylene therefrom, and the details of such process described herein.