Membrane Mediated Extraction Process for Olefin/Paraffin Separation

78098S Ethylene and propylene, two of the most important building blocks of the U.S. petrochemical industry, are produced by steam cracking of ethane, propane, or heavier hydrocarbons and are also a by-product of fluid catalytic cracking. Unfortunately, as produced, these species are always in admixture with other species from which they must be separated. The conventional method of separation is cryogenic distillation, which is extremely energy intensive. In addition to ethane and propane, there are numerous liquid streams in chemical plants that contain olefins that must also be separated from other components by distillation. This project will demonstrate the efficacy of membrane mediated extraction for the recovery of olefins from both dilute liquid streams and from more concentrated gas streams. During Phase I, selected solvents and complexing agents will be synthesized and used in a laboratory apparatus that will be built to measure the flux and selectivity for ethyelene/ethane mixtures, propylene/propane mixtures and for dilute 1-octene streams in n-octane (that simulates a waste stream of high commercial interest). Effect of solvent type, complexing agent composition, feed flow rate, temperature, membrane area and other parameters will be determined systematically during the experimental work. Commercial Applications and Other Benefits as described by the awardee: The first anticipated application for this process is the recovery of 1-octene from a waste stream produced by a major chemical company in Texas. The waste stream contains approximately 1 wt % 1-octene in Isopar E (an isoparaffininc solvent) and is currently incinerated for lack of a cost-effective method of recovering the olefins. Therefore, the process also should result in environmental credits for eliminating incineration. Once demonstrated on for this application, the process will be applied to ethane/ethylene or propane/propylene separation in steam cracking operations.