OLEFIN PLANT RECOVERY SYSTEM EMPLOYING CATALYTIC DISTILLATION

摘要

The C2 to C5 and heavier acetylenes and dienes in a thermally cracked feed stream are hydrogenated without significantly hydrogenating the C2 and C3 olefins. Additionally, the C4 and heavier olefins may be hydrogenated. Specifically, the cracked gas feed in an olefin plant is hydrogenated in a distillation reaction column containing a hydrogenation catalyst without the necessity of separating the hydrogen out of the feed and without any significant hydrogenation of the ethylene and propylene . A combined reaction-fractionation step known as catalytic distillation hydrogenation is used to simultaneously carry out the reactions and separations while maintaining the hydrogenation conditions such that the ethylene and propylene remain substantially unhydrogenated and essentially all of the other C2 and heavier unsaturated hydrocarbons are hydrogenated. Any unreacted hydrogen can be separated by a membrane and then reacted with separated C9 and heavier materials to produce hydrogenated pyrolysis gasoline.