US 7,550,638 B2
	Integrated cracking and metathesis process
Robert S. Bridges, Friendswood, Tex. (US); and Steven T. Coleman, Humble, Tex. (US)
Assigned to Equistar Chemicals, LP, Houston, Tex. (US)
Filed on Nov. 16, 2005, as Appl. No. 11/280,789.
Prior Publication US 2007/0112236 A1, May 17, 2007
Int. Cl. C07C 6/04 (2006.01); C07C 2/06 (2006.01)

U.S. Cl. 585—324  [585/329; 585/330; 585/646; 585/647; 585/643; 585/512; 585/513]

7 Claims

1. 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.