Custom Amorphous Fluoropolymer Facilitated Transport Membrane for Olefin-Paraffin Gas Mixture Separation

Light olefins such as ethylene and propylene are important petrochemical feedstocks and are among the top ten chemicals produced annually. The separations of olefins from paraffins via distillation are highly energy and capital intensive. There is an enormous economic incentive to develop alternative separation processes with lower energy consumption. A membrane based olefin-paraffin separation technology has the potential to provide substantial economic benefit to petrochemical industry and drastically reduce the energy required. While olefin-paraffin separations with membranes have been demonstrated in the laboratory, membrane technology has not been applied to industrial applications primarily due to the problems of membrane stability.

Compact Membrane Systems (CMS) has developed customized amorphous fluoropolymer (CAF) membranes containing silver ions that selectively transport olefin molecules from a mixture of olefin and paraffin. These facilitated transport membranes show stable performance over a year with high olefin flux and olefin/paraffin selectivity. Tests were carried out with propylene-propane and ethylene-ethane systems. A broad range of tests have also been conducted to characterize the membrane resistance to common poisons such as hydrogen, acetylene, butadiene, carbon dioxide and carbon monoxide that are common in refinery streams. These silver based membranes have been tested in the laboratory with an actual refinery gas mixture. We have scaled up the membrane module from 10 cm² to 5000 cm² area and performed separation at a larger scale. A pilot system with a larger membrane module has been installed at the Delaware City Refining Company (DCRC) site in Delaware City, DE. The testing of the pilot unit has been initiated to provide real-world evidence of membrane stability in realistic conditions validating our laboratory testing. Laboratory and pilot unit test results as well as some of our economic modeling results will be discussed in this presentation.