Unlike similar technologies that are in the development stage, Permylene membrane systems can be effectively used over the widest range of olefin/paraffin ratios. Olefin purity in the permeate stream from a Permylene membrane system is typically > 99.5% regardless of the olefin content in the feed stream. Olefin recovery depends in large part on the olefin concentration in the mixed gas feed stream as well as the available partial pressure differential between the mixed gas feed stream and the allowable permeate (product) pressure. The higher the olefin content in the feed stream, the higher the recovery of the olefin possible. The greater the partial pressure differential available between the feed stream and the permeate stream, the higher the recovery of the olefin.