Patent ID: 8071044

Claim:
An apparatus for isomerization of a feedstock comprising paraffins having between 5 and 6 carbon atoms to provide a gasoline fraction comprising: a. an isomerization reactor ( 106 ) being adapted to receive feedstock at an inlet and having an outlet, b. a deisohexanizer ( 116 ) having an inlet in fluid communication with the outlet of isomerization reactor ( 106 ), a lower boiling outlet adapted to remove a lower boiling fraction via line ( 118 ), a outlet to provide a side-cut fraction and a higher boiling outlet; and c. a membrane separator ( 124 ) having a feed side inlet in fluid communication with the outlet to provide a side-cut fraction of the deisohexanizer ( 116 ), a feed side outlet in direct fluid communication with line ( 118 ) from the lower boiling outlet of the deisohexanizer ( 116 ), and a permeate outlet in fluid communication with the inlet of the isomerization reactor ( 106 ) wherein the membrane separator is a sieving membrane having a C 6 Permeate Flow Index of at least 0.01 and a C 6 Permeate Flow Ratio of at least 1.25:1.