The present invention provides a process for selectively hydrogenating
C.sub.2 -C.sub.10 greater unsaturated hydrocarbons (acetylenes and
diolefins) at the upstream side of a front depropanizer or front
deethanizer in an olefin production plant. After passing through a mixed
phase hydrogenation reactor to selectively hydrogenate, the olefin plant
process stream passes to a front depropanizer or front deethanizer. The
process according to the present invention is able to selectively
hydrogenate C.sub.2 -C.sub.10 greater unsaturated hydrocarbons (including
acetylene), to reduce the number of equipments, the amount of equipment
fouling and the energy consumption.
