Patent ID: 7550638

Claim:
An integrated method for cracking an ethane containing feed and metathesizing ethylene to propylene, comprising thermally cracking said feed to form a first stream ( 16 ) containing ethane, ethylene and hydrocarbons heavier than ethane and ethylene and including 2-butenes, subjecting said first stream to a first fractional distillation ( 17 ) to form a second stream ( 18 ) containing at least some of said ethane and ethylene in said first stream and a third stream ( 24 ) containing predominantly said hydrocarbons in said first stream that are heavier than ethane and ethylene, recovering chemical grade propylene ( 65 ) from said third stream as a product of the overall process, subjecting a first portion ( 60 ) of said second stream to an ethylene dimerization operation to form a dimerization product stream ( 43 ) that contains newly formed butenes, subjecting a second portion ( 61 ) of said second stream to a metathesis operation wherein 2-butenes are subjected to disproportionation conditions in the presence of ethylene to form a propylene containing stream ( 50 ), passing said propylene containing stream from said metathesis operation as feed to said first fractional distillation, passing said dimerization product stream to a butene recovery operation to form a first butene containing stream ( 48 ), passing said first butene containing stream as feed to said metathesis operation, separating a second butene containing stream ( 26 ) from said third stream, and passing said second butene containing stream to said butene recovery operation.