Patent ID: 7601309

Claim:
An apparatus for converting an olefinic C 4 stream comprising isobutene, butene-1, and butadiene to propylene and octenes, comprising: a) a selective hydrogenation zone, having a catalyst bed for removal of butadiene by partial hydrogenation to butene and for conversion of butene-1 to butene-2; b) in downstream connection with the selective hydrogenation zone, a first separation zone, for separating an effluent of the selective hydrogenation zone into a vapor fraction containing butene-1 and compounds boiling at lower temperatures than butene-1, and a liquid fraction containing compounds boiling at higher temperatures than butene-1; c) in downstream connection with the vapor fraction leaving the first separation zone, a first dimerization zone containing a catalyst; d) in downstream connection with the first dimerization zone, a second separation zone for separating an effluent of the first dimerization zone into an octene-rich liquid and a C 4 -rich vapor stream; e) a connection for feeding the octene-rich liquids from the second separation zone to the first separation zone; f) a means for removing a bottoms product from the first separation zone, the bottoms product containing substantially all of the octene from the octene-rich liquids; and g) a means for removing a third product containing butene-2 as a mid-cut from the first separation zone, and supplying the third product to a metathesis zone for metathesis of the third product with ethylene to produce propylene in the presence of a catalyst.