Production of gasoline from light olefins in a fluidized catalyst reactor system

A continuous process for upgrading a variable throughput light olefinic gas feedstream rich in ethylene and C.sub.3 -C.sub.4 aliphatic hydrocarbons in a fluidized bed catalytic conversion zone, comprising the steps of:

• maintaining an oligomerization reactor containing a fluidized bed of zeolite catalyst particles in a low severity reactor bed at oligomerization temperature conditions by passing hot olefinic gas upwardly through the fluidized catalyst bed under throughput rate conditions sufficient to convert at least 50 wt % of lower olefins to hydrocarbons in the C.sub.5 -C.sub.10 range;
• maintaining turbulent fluidized bed conditions through the fluidized bed by passing fresh ethene-rich feedstream gas upwardly through the fluidized catalyst bed and adding thereto sufficient recycled light byproduct gas to maintain a superficial gas velocity of about 0.3 to 2 meters per second.
• cooling reaction effluent from the conversion zone to provide light gas byproduct and liquid hydrocarbon reaction product rich in C.sub.5 -C.sub.9 hydrocarbons;
• recycling sufficient light byproduct gas recovered from effluent for maintaining turbulent regime gas velocity in the fluidized bed.

A process for upgrading light olefinic crackate gas from hydrocarbon cracking, said light crackate gas containing ethene, propene and other C.sub.1 -C.sub.4 lower aliphatics, comprising the steps of:

• (a) fractionating heavy oil crackate in a main fractionation column to recover distillate range hydrocarbon product, naphtha and light crackate gas;
• (b) compressing and cooling the light crackate gas to provide a first pressurized ethene-rich vapor stream and a first condensed crackate stream rich in C.sub.3.sup.+ aliphatics;
• (c) contacting the first ethene-rich vapor stream under pressure with a C.sub.5.sup.+ liquid sorbent stream in an absorber column under sorption conditions to selectively absorb a major amount of C.sub.3.sup.+ components and recover a second ethene-rich vapor stream from the absorber column;
• (d) contacting said second ethene-rich vapor stream in a fluid bed reactor with a turbulent regime fluidized bed of acid medium pore zeolite oligomerization catalyst particles under oligomerization conditions to produce a hydrocarbon effluent stream rich in C.sub.5.sup.+ hydrocarbons;
• (e) cooling the reaction effluent stream to provide light gas byproduct and liquid hydrocarbon reaction product;
• (f) contacting a first light gas byproduct portion from step (e) with a sponge oil in a secondary sponge absorber having a bottom portion operatively connected to receive reaction effluent for recovery of liquid hydrocarbons;
• (g) recycling a second light byproduct gas portion in an amount sufficient to maintain turbulent regime gas velocity in the fluid bed reactor of step (d);
• (h) passing sponge oil sorbate liquid from the secondary absorber to the main fractionation column for recovery;
• (i) flashing substantially the entire cooled reaction effluent stream from step (e) into the bottom section of the secondary sponge absorber;
• and
• (j) passing liquid reaction product from step (e) with sponge oil liquid to the main fractionation column separation step (a) for recovery therein.