EXTRACTIVE DISTILLATION PROCESS FOR RECOVERING BUTADIENE FROM C4 HYDROCARBON MIXTURES

摘要

High purity 1,3 butadiene is recovered from a C₄ fraction containing butadienes, butenes, butanes, and acetylenes that is generated from a steam cracker by extractive distillation operating with no reflux or greatly reduced reflux conditions. This technique of using a substantially reduced reflux is generally applicable to any butadiene recovery process in which at least one extractive distillation column (EDC) is used to separate 1,3 butadiene from other C₄ components in the mixture. For an ED process with two EDCs, significant reductions in total energy requirements in the both EDCs can be achieved by appropriate reductions in the reflux in each column. More importantly, the performances of both EDCs are virtually unaffected when operated under greatly reduced reflux.