Integration of Gas Separation Membranes with IGCC Identifying the right membrane for the right job

A core mission of the U.S. Department of Energy's (DOE) Carbon Sequestration Program is to foster the development of commercially-ready technologies for CO2 capture and sequestration. An R&D program goal of 90% carbon capture, at an increase in the cost of electricity (COE) no greater than 10% above current state-of-the-art designs without capture, has been established for electric power generation from next-generation Integrated-Gasification Combined-Cycle (IGCC) plants. Advanced gas separation membranes for separating H-2 from CO2 are one possible technology for achieving these goals. For IGCC CO2-capture applications, membranes will need to out-perform existing chemical and physical absorption processes. Gas separation membranes, however, can be integrated into a number of different locations in the IGCC process in addition to post water-gas-shift (WGS), the preferred location for current absorption technologies. Due to the many integration options possible, membranes could potentially be required to operate over a wide range of conditions. It is preferred that the membrane operate at pressures and temperatures normally encountered at that point in the IGCC flowsheet where it is being placed. And, clearly it is beneficial that the membrane be placed in a location with relatively high pressure in order to maximize separation. If this is possible, the feed and product gases need not be compressed/expanded or heated/cooled. In addition, membrane materials being considered, whether ceramic, metallic or polymeric, have physical and chemical limitations in regards to operating temperature and tolerance to various compounds that might be present in synthesis gas. It is therefore unlikely that one type of membrane will be able to perform over the entire range of conditions possible. In this paper, we identify preferred membrane locations and quantify performance requirements for a wide range of membrane materials currently under consideration for H-2/CO2 separation. (C) 2008 Elsevier Ltd. All rights reserved