Multistage process for converting olefins or oxygenates to heavier hydrocarbons

Claim 1

A continuous catalytic process for converting olefinic feedstock comprising ethylene and C 3 + olefins to heavier liquid hydrocarbon product comprising the steps of (a) prefractionating the olefinic feedstock to obtain a gaseous stream rich in ethylene and a liquid stream containing C 3 + olefin; (b) heating and contacting the liquid stream from the prefractionating step with shape selective medium pore zeolite oligomerization catalyst in a distillate mode catalytic reactor system at elevated temperature and pressure to provide a heavier hydrocarbon effluent stream comprising distillate, gasoline and lighter hydrocarbons; (c) fractionating the effluent stream to recover distillate, gasoline and lighter hydrocarbons; (d) recycling at least a portion of the recovered gasoline as a first liquid sorbent stream to prefractionating step (a); (e) further reacting the recycled gasoline together with sorbed C 3 + olefin in the catalytic reactor system of step (b); (f) combining said ethylene-rich gaseous stream from step (a) with a liquid hydrocarbon stream containing heavier liquid hydrocarbons; (g) contacting the combined ethylene-rich stream at elevated temperature and pressure in a high severity reaction zone with shape selective medium pore zeolite oligomerization catalyst to convert at least a portion of the olefinic components to heavier hydrocarbons; (h) cooling oligomerization reaction effluent from step (g) to condense at least a portion of said heavier hydrocarbons; (i) separating the cooled and partially condensed effluent stream from step (h) into a vapor stream comprising unreacted light olefin and a condensed liquid hydrocarbon stream; (j) fractionating said condensed liquid hydrocarbons from step (i) to provide a second liquid recycle sorbent stream and at least one product hydrocarbon stream; (k) contacting the vapor stream from separation step (i) under sorption pressure conditions with cooled recycle sorbent stream to sorb said unreacted light olefin into the second sorbent stream; and (l) recycling the second sorbent stream rich in olefin for further conversion with said olefinic feedstock in step (g).