High Yield Membrane ReactorsEPA Grant Number: R824727
Title: High Yield Membrane Reactors
Investigators: Rezac, Mary , Beckham, Haskell
Current Investigators: Rezac, Mary
Institution: Duke University
EPA Project Officer: Karn, Barbara
Project Period: October 1, 1995 through September 30, 1998
Project Amount: $269,999
RFA: Technology for a Sustainable Environment (1995) Recipients Lists
Research Category: Sustainability , Pollution Prevention/Sustainable Development
Description:This project examines the ability to produce thermally stable polymeric membranes for use in membrane reactors. The focus of this research program is on the synthesis of a series of diacetylene-functionalized polyimides, evaluation of their ability to transport and separate gases, and their thermomechanical stability. It is anticipated that these membranes will find use in high temperature membrane reactor systems.
The polymers chosen are unique in that they are soluble in simple organic solvents at room temperature and can be processed to produce asymmetric membrane structures through standard techniques. Following post-production crosslinking, however, they become thermally stable in inert environments to well above 300 F (161 C) and are then completely insoluble in the solvents used to cast them. Unlike other thermally stable polymers that are essentially insoluble, brittle, and extremely difficult to process, the diacetylene-functionalized polyimides are easily processed into complex structures. Polymeric membranes offer significant advantages over microporous ceramic or metallic membranes when the overall operation of a membrane reactor is examined. Only polymeric membranes can achieve both high separation selectivities, high transport rates, and extended use for temperatures up to 300 F (161 C).
Use of membranes to selectively remove a single product from a reaction mixture can dramatically improve the operation of thermodynamically limited reactor systems. Initial research focuses on dehydrogenation reactors. Use of the membranes developed here will markedly decrease the formation of undesired by-products, extend run times, and reduce the waste production rates for these systems. This change in processing could reduce the rate of carbon dioxide production by a factor of over 100. Commercially important reactions that may be amenable to this technology include the dehydrogenation of isobutane and pentane to produce olefins for gasoline, ethyl benzene conversion to styrene used in the production of plastics, and the production of high purity aldehydes from alcohols used in flavors and fragrances.