Patent ID: 7696394

Claim:
A dehydrogenation process comprising: providing a dehydrogenation system comprising a dehydrogenation reactor and a separation system, wherein the separation system comprises a first column and a second column; introducing an alkyl aromatic hydrocarbon into the dehydrogenation reactor; contacting the alkyl aromatic hydrocarbon with a dehydrogenation catalyst disposed within the dehydrogenation reactor to form a dehydrogenation output stream comprising a vinyl aromatic hydrocarbon; passing at least a portion of the dehydrogenation output stream to the first column; recovering a first overhead fraction comprising benzene and a first bottoms fraction from the first column; passing at least a portion of the benzene from the first column to an alkylation system comprising an alkylation catalyst; passing the first bottoms fraction from the first column to the second column; recovering a second overhead fraction and a second bottoms fraction from the second column; withdrawing offtest from the effluent stream of the dehydrogenation reactor to form withdrawn offtest, wherein the offtest comprises effluent not meeting further processing specification introducing the withdrawn offtest directly into the second column separation.