(356d) Opportunities for CO2-Selective Membranes in Hydrogen Purification

Syngas operations require separation of CO₂ from hydrogen for various reasons, not only for CO₂ capture from IGCC operations, but for a number of existing refinery and petrochemical applications.  Membrane technology is an attractive approach to CO₂ capture because of inherent advantages such as modularity, high energy efficiency and good reliability.  MTR has been developing CO₂-selective Polaris^TM membranes, which are highly permeable to CO₂ and reject the other major components of syngas, including H₂, CO and CH₄.  Polaris membranes have CO₂ permeances approximately ten times higher than other commercial CO₂-selective membranes.  This combination of permeance and selectivity meets the target range necessary to yield a competitive membrane-based process for hydrogen purification and/or CO₂ capture and sequestration.

This presentation will describe how multi-stage and multi-step membrane process designs can be used to minimize membrane area, compressor power requirements, and hydrogen loss during hydrogen recovery from syngas.  A preliminary process simulation study shows that a Polaris-based membrane process can achieve 99% hydrogen recovery, and capture 97% of CO₂ as a sequestration-ready liquid stream.  Currently, MTR is working with the U.S. DOE National Carbon Capture Center (NCCC, operated by Southern Company) to conduct field tests of Polaris membranes at a coal-fired power plant.  Results of the tests will be summarized, and  critical issues such as long-term stability in practical applications and the impact of contaminants on system performance will be addressed.  Future plans for running a 0.1 MW_e (500 lb/hr syngas) CO₂ capture/hydrogen purification membrane system and issues associated with eventual scale-up to full commercial operation will also be discussed.