To produce high-purity butene-1 from a mixed C4 stream using Lummus’ comonomer production technology (CPT). The feedstock can contain any amount of butene-1, butene-2 and butane.
The CPT process for butene-1 production has two main steps: butene isomerization and butene distillation. While the following description uses raffinate-2 feed, steam-cracker raw C4s or raffinate-1 can be used with additional steps for butadiene hydrogenation or isobutene removal before the CPT unit.
In the butene isomerization section (1), raffinate-2 feed from OSBL is mixed with butene recycle from the butene distillation section and is vaporized, preheated and fed to the butene isomerization reactor, where butene-2 is isomerized to butene-1 over a fixed bed of proprietary isomerization catalyst. Reactor effluent is cooled and condensed and flows to the butene distillation section (2) where it is separated into butene-1 product and recycle butene-2 in a butene fractionator. Butene-1 is separated overhead and recycle butene-2 is produced from the bottom. The column uses a heat-pump system to efficiently separate butene-1 from butene-2 and butane, with no external heat input. A portion of the bottoms is purged to remove butane before it is recycled to the isomerization reactor.
Licensor: Lummus Technology