CO₂-selective membranes for hydrogen production and CO₂ capture - Part I: Membrane development

Syngas operations require separation of CO₂ and hydrogen for hydrogen production at refineries and petrochemical plants, and potentially for combined hydrogen production and CO₂ capture at integrated gasification combined cycle (IGCC) power plants. Membranes that selectively permeate CO₂ have attracted significant interest, because the purified hydrogen is retained at high pressure, thus avoiding costly downstream recompression. In this work, Polaris^™ thin film composite membranes were evaluated for CO₂ removal from syngas: these membranes are highly permeable to CO₂ and reject the other major components of syngas, including hydrogen, carbon monoxide and methane. Part I of this study describes the three-stage development of Polaris membranes for CO₂/H₂ separation, including: laboratory parametric tests of membrane stamps using pure- and mixed-gas streams, pilot-scale tests of membrane modules using real syngas at a coal-fired gasification plant, and field demonstration of a membrane system producing liquid CO₂. The gasification plant where the field tests were conducted is at the National Carbon Capture Center (NCCC) in Wilsonville, AL. The membrane demonstration system processed 227 kg/h of syngas (equivalent to a 0.15MW_e IGCC power plant) containing ~9% CO₂, and produced a liquid CO₂ stream containing 95+% CO₂. Part II of this study will explore the potential opportunities for the use of CO₂-selective membranes in commercial hydrogen purification and CO₂ capture, including the results of techno-economic analyses for various process designs.