Membrane-based system for low-cost CO2 capture to be demonstrated at engineering scale

A new membrane technology for separating carbon dioxide from exhaust gas will be scaled up for real-world testing under a project to evaluate low-cost CO2 capture at a coal-fired power plant. Design and testing of an engineering-scale CO2-capture system will be jointly overseen by GTI (Des Plaines, Ill; www.gti.energy) and The Ohio State University (Columbus, Ohio; www.osu.edu). The project aims to conduct tests on coal fluegas at the Wyoming Integrated Test Center. The CO2-selective membrane, developed by Ohio State researchers, consists of a layer of non-volatile, amino-group-containing compounds coated onto a nanoporous polymer support. When CO2-containing fluegas contacts the membrane, CO2 molecules dissolve into the membrane by combining reversibly with the amino groups in the membrane to form protonated amine cations and bicarbonate anions. The ions are transported across the membrane via two separate routes in a “facilitated transport” mechanism — in the first, the CO2 molecule “hops” from one covalently bound amino-group site to subsequent adjacent sites, and in the second, CO2 reacts with a mobile carrier (an amino acid salt) that diffuses across the membrane (diagram). CO2 is released to the low-pressure side of…