Membrane Systems for Coal Bed Carbon Dioxide Sequestration and Methane Production

In order to reduce the accumulation of greenhouse gases, it has been proposed to sequester the carbon dioxide from the flue gas of coal power plants by injecting the CO2 into unmineable coalbeds. The methane gas displaced by the carbon dioxide could be recovering and sold, thereby covering the cost of sequestration. However, nitrogen and oxygen typically is injected along with the carbon dioxide, which leads to a coalbed methane product contaminated with multiple impurities. Conventional gas processing technology applied to such contaminated gas is expensive and complex. This project will develop a membrane process that can remove all of the main impurities in a single operation. In Phase I, membranes with good properties for separating carbon dioxide, nitrogen, oxygen, and water from methane were produced and evaluated as bench-scale membrane modules. A preliminary technical and economic analysis showed that the process would be cost effective. In Phase II, the technology will be scaled up, and pilot-scale or small-industrial-scale membrane modules will be produced and installed in a field test system at a coalbed methane gas processing plant. Commercial Applications and Other Benefits as described by the awardee: The membrane process should find wide applicability in the treatment of natural gas containing multiple contaminants. Coalbed methane produced by the injection of flue gas is one such gas stream.