Patent ID: 11939289
Assignee: LUMMUS TECHNOLOGY LLC
Field: Chemical engineering (Chemistry)
Classification: CPC C  B  Y | IPC B  C

Claim 8:
9. A process for the dimerization of isoolefins, the process comprising:
feeding an oxygenate reaction modifier and a hydrocarbon feed to a fixed bed reactor containing an oligomerization catalyst, the hydrocarbon feed comprising isobutene and a secondary feed comprising butanes;
reacting isobutene in the fixed bed reactor at oligomerization conditions to form a reaction effluent comprising the oxygenate reaction modifier, isobutene dimers, unreacted isobutene, any oxygenate reaction byproducts formed, as well as butanes;
without componential separation, feeding the reaction effluent to a second fixed bed reactor containing an oligomerization catalyst;
reacting the unreacted isobutene in the second fixed bed reactor at oligomerization conditions to form additional isobutene dimers, recovering a second reaction effluent comprising oxygenate reaction modifier, isobutene dimers, any oxygenate reaction byproducts formed, as well butanes;
without componential separation, feeding the second reaction effluent to a catalytic distillation reactor having a reactive distillation zone comprising an oligomerization catalyst;
concurrently within the catalytic distillation reactor:
reacting unreacted isobutene in the second reaction effluent to form additional isobutene dimers;
separating the dimers and the oxygenate reaction byproducts, recovered as a bottoms fraction, from the isobutane and n-butane, and any unreacted isobutene, recovered as an overheads fraction; and

recycling the overheads fraction to the hydrocarbon feed;
wherein the bottoms fraction further comprises the oxygenate reaction modifier and isobutene trimers, the process further comprising separating the bottoms fraction in a divided wall distillation column to recover an overheads fraction, a side draw fraction comprising the isobutene dimers, and a bottoms fraction comprising the isobutene trimers; and
wherein one or both of the bottoms fraction from the divided wall distillation column and the overheads fraction from the divided wall distillation column comprise oxygenated byproducts or comprise the oxygenate reaction modifier, the process further comprising:
recovering the oxygenate reaction modifier or oxygenated byproducts from one or both of the bottoms fraction from the divided wall distillation column and the overheads fraction from the divided wall distillation column; and
recycling the recovered oxygenate reaction modifier or oxygenated byproducts to the fixed bed reactor, the second fixed bed reactor, the catalytic distillation reactor, or a combination thereof.