SBIR Phase II: Carbon-Ceramic Composite Membranes for Olefin-Paraffin Separations

This Small Business Innovation Research Phase II project proposes to continue the development of carbon-ceramic membranes with excellent propylene/propane separation performance. The membranes serve as the enabling technology to be used in an environmentally benign and economically viable membrane process to separate propylene from propane for a variety of important petrochemical and refining processes. These composite membranes contain thin selective layers of a newly-developed microporous carbon material. The rigid structure of the material confers the membranes with exceptional resistance to plasticization. This allows the membranes to retain high mixed-gas selectivities at challenging industrial conditions. The mixed-gas propylene/propane selectivities and stability of the membranes achieved in Phase I work are far superior to those of previously examined polymer and facilitated transport membranes under industrially relevant conditions. In Phase II work, membranes developed in Phase I will be further optimized, and then used to produce prototype commercial-size modules for propylene/propane separations. In addition, this research is expected to increase general understanding of carbon-ceramic membranes and their potential for use in an array of other chemically and thermally challenging gas separations that are not possible with conventional polymeric membranes. The broader impact/commercial potential of this project will be the use of the new carbon membranes for propylene recovery from polypropylene and propylene derivative reactor purge streams. This technology has important economic potential, considering the large volumes of propylene, polypropylene and other propylene derivatives produced annually in the petrochemical industry. With successful development and demonstration of the membrane-based processes, their potentially much larger applications include propylene/propane separations for monomer production at steam crackers and recovery of propylene from fluid catalytic cracker off-gases in refineries. The cost of making ceramic membranes is higher than that of polymeric membranes, but the savings from lower process energy requirements will easily outweigh the increased membrane costs. If successful, the new membranes will make membrane-based olefin/paraffin separations technically and economically attractive for use in conjunction with, or in place of, distillation.