| abstract |
A process for the production of propylene and high octane blending components from C3 and C4 hydrocarbons that provides the dual benefit of flexibility between alkylate and propylene products while allowing the processing of large amounts of normal butane. The process includes the steps of passing a combined feed of C3 and C4 hydrocarbons to a dehydrogenation zone, contacting the feed stream with a dehydrogenation catalyst, and recovering an effluent containing C3 and C4 olefins and admixing the effluent with another feed comprising paraffins and olefins having from 3-4 carbon atoms and recovering an intermediate stream. The intermediate stream enters a separation zone, which removes C2 hydrocarbons and lower boiling materials from the process, recovers a first propylene product stream, produces an alkylation zone feed stream containing C3 and C4 hydrocarbons, and produces a recycle stream. The alkylation zone feed is combined with make-up isobutane and enters an alkylation zone to produce an alkylation zone effluent containing high octane blending components comprising C7 and C8 hydrocarbons. After separating the alkylation zone effluent into the C7 and C8 product stream and a recycle stream rich in normal butane, the normal butane-rich recycle stream is combined with the propane recycle and a C4 paraffin stream to form the feed to the dehydrogenation zone. Additional products may be obtained by passing the alkylation zone feed first through an etherification zone and then into the alkylation zone. |