Process to remove benzene from refinery streams

Abstract

A substantially benzene-free product suitable for gasoline blending is formed from a benzene-containing refinery stream. At least about 30% of the benzene initially present in the stream is catalytically alkylated with C.sub.2 -C.sub.4 olefins to form alkylated products. Most preferably, the alkylation zone is present in the distillation column and the alkylated products drop to the lower portion of the column and are recovered with the heavy fraction. Alternatively, the alkylation zone is downstream of the distillation column and a secondary distillation column removes the heavier alkylated products. The remaining light fraction is hydrogenated to convert substantially all of the remaining non-alkylated benzene to cyclohexane and is isomerized to boost the octane of C.sub.5 -C.sub.7 paraffins, preferably in a single reactor. The combined light and heavy fractions, which contain the debenzenated and isomerized product and the alkylated benzene, can be combined to provide a substantially benzene-free gasoline blending stock, It is produced without deleterious effect on octane numbers and with increased volume as compared to the original refinery stream.