Separation of 1-hexene/n-hexane mixtures using a hybrid membrane extraction system

Previously reported techniques for the separation of gaseous olefins from paraffins by means of membrane contactors, and fluid olefins from paraffins by means of liquid extraction, have been extended to the separation of liquid olefin/paraffin mixtures by means of a hybrid membrane/extraction system. In this paper, emphasis is placed on the development of a hybrid membrane contacting system for the separation of liquid olefin/paraffin mixtures in the range up to C-6. The membrane contacting system described comprises non-porous polymeric membranes and a high-boiling-point selective liquid extractant flowing along polymeric membranes between the extractor and the membrane stripper at various temperatures and flow rates. The olefin components permeated through the polymeric films at elevated temperatures in a membrane stripper, making it possible to effect pervaporation transport. Selectivities of 1-hexene/n-hexane separations ranged from 40 to 70. The l-hexene permeation rate achieved at 62 degrees C was up to 1.4 x 10(-6) g/s cm(2). (C) 1999 Elsevier Science B.V. All rights reserved.