GB743621A - Prewash for acetylene removal from butadiene stream - Google Patents

Abstract

<PICT:0743621/IV(a)/1> Acetylenes are separated continuously from a mixture thereof with butadiene by contact with an aqueous solution of a cuprous salt which absorbs the acetylenes, separating, at 20-50 DEG F., the aqueous solution together with a little butadiene from the majority of the butadiene, passing the aqueous solution to a zone wherein butadiene is vaporized and separated from the aqueous solution, and subsequently passing the aqueous solution to a zone where acetylenes are stripped therefrom at 140-180 DEG F. by injection of an inert hydrocarbon gas. The gas mixture and cuprous salt solution pass through a chiller 5 wherein the temperature is reduced to 20-50 DEG F. and passed to a settler drum 9, the butadiene being taken off through a pipe 10, and passed to a butadiene extraction plant, whilst the aqueous solution passes through pipe 11 to a desorber 12, either cold through a pipe 20a or through a preheater 13. Gaseous butadiene is taken off through a line 21, at 50-90 DEG F., and is sufficiently pure to be mixed with that treated in the butadiene extraction plant. The feed and bottoms temperature of the desorber is 140-180 DEG F. and the solution containing acetylenes passes to a stripper 24 where the acetylenes are scrubbed by water and vented through a line 31 whilst aqueous ammonia drains through a line 30. Typical pressures are desorber-up to 30 p.s.i.g.; stripper-up to 5 p.s.i.g.