Industrial grade 1-butene/isobutane separation using supported liquid membranes

Abstract

Removal of olefin gaseous compounds such as ethylene, propylene, 1-butene and butadiene from paraffins is one of the most crucial issues in the petrochemical industries. The supported liquid membrane of silver nitrate solution supported in PVDF microfilter membrane was used for 1-butene/isobutane separation in the current study. The effects of silver nitrate concentration, trans-membrane pressure and gaseous feed stream’s humidity were investigated on the membrane separation performance. According to the results, as the salt concentration increased from 0 to 3M, 1-butene permeance and 1-butene/isobutane selectivity were increased from 1.96×10−5 to 0.0607gpu and 0.0004 to 1380, respectively. In the liquid membrane containing aqueous solution of 1M silver nitrate, 1-butene/isobutane selectivity were found as 100 and 330 for the dry and humidified feed gas streams. Cu(NO3)2.3H2O salt was used simultaneously with the silver salt in the aqueous liquid membrane in order to increase the long-term stability of the membrane in addition to the feed stream humidification. As the both salts were used simultaneously in 1M concentration, 1-butene/isobutane selectivity decreased slightly from 439 to 399, while the 1-butene permeance increased from 0.0227 to 0.075gpu, during 4h continuous operation.