Patent ID: 6194626
Filing Date: 2001-02-27
Classification: C10G

Abstract:
A process for the purification of a diolefin hydrocarbon stream from a naphtha steam cracker and containing trace quantities of acetylene compounds and the cyclic regeneration of an at least partially spent selective hydrogenation catalyst which process comprises:(a) introducing a naphtha feedstock and a recycle stream comprising naphtha and polymer compounds into a naphtha steam cracker to produce a diolefin hydrocarbon stream containing trace quantities of acetylene compounds;(b) passing said diolefin hydrocarbon stream containing trace quantities of acetylene compounds and elemental hydrogen into a selective hydrogenation zone to selectively hydrogenate at least a portion of said acetylene compounds and to produce an at least partially spent selective hydrogenation catalyst;(c) passing the resulting effluent from said selective hydrogenation zone in step (b) to a fractionation zone to produce a diolefin hydrocarbon stream having a reduced concentration of acetylene compounds;(d) contacting the at least partially spent selective hydrogenation catalyst in said selective hydrogenation zone with a stream comprising naphtha and hydrogen to reduce the polymer content of the selective hydrogenation catalyst to thereby increase hydrogenation activity;(e) passing the resulting effluent from said selective hydrogenation zone in step (d) to said fractionation zone to produce a stream comprising naphtha and polymer compounds;(f) recycling at least a portion of said stream comprising naphtha and polymer compounds to provide at least a portion of said stream comprising naphtha and hydrogen in step (d);(g) recycling at least another portion of said stream comprising naphtha and polymer compounds to step (a);(h) recovering said diolefinic hydrocarbon stream having a reduced concentration of acetylene compounds produced in step (c); and(i) reintroducing said diolefin hydrocarbon stream containing trace quantities of acetylene compounds and elemental hydrogen into said selective hydrogenation zone after contact and extraction with said stream comprising naphtha and hydrogen.