Patent ID: 7728185

Claim:
A process for increasing the yield of propylene from hydrocarbons comprising: passing a hydrocarbon feedstream to a cracking unit, thereby creating an effluent; separating the effluent into an ethylene stream, a propylene stream, a C4 stream, and a pygas stream; passing the C4 stream to a selective hydrogenation reactor thereby creating a C4 effluent stream having a reduced diolefin content; separating the C4 effluent stream into a normal butane stream comprising n-butane and 2-butene, and isobutane stream comprising isobutane, isobutene and 1-butene; passing the normal butane stream and the ethylene stream to a metathesis reactor, thereby creating a propylene stream; passing the isobutane stream to an alkylation and oligomerization reactor, thereby creating an alkylation effluent stream comprising hydrocarbons having 8 or more carbon atoms, and depleted in butanes and butenes; separating the alkylation effluent stream into an olefin cracking unit feedstream rich in hydrocarbons having 8 or more carbon atoms, and a butane effluent stream having butanes and butenes; passing the olefin cracking unit feedstream to an olefin cracking unit, thereby creating a second C4 stream, comprising butanes and butenes, and a second effluent stream rich in ethylene and propylene; and passing the second C4 stream to the selective hydrogenation reactor.