CO2 capture from coalbed methane using membranes: a review

Abstract

Coalbed methane is an abundant form of natural gas extracted from coal beds. Coalbed methane is viewed as a cleaner energy source versus petroleum and coal combustion because methane extraction, transport and use are more efficient and less polluting. However, coalbed methane contains high amounts of CO2 that induce solidification during liquefaction. Therefore, CO2 has to be reduced below 2% to meet the pipeline transportation standards. In addition, CO2 capture would reduce the amount of gas emissions to the atmosphere, thus mitigating global warming. Here, we review membrane absorption, which is an advanced method for CO2 capture from coalbed methane, by controlling the gas and liquid phases separately during the operation process. We compare CO2 removal methods for various coalbed methane sources. Parameters influencing CO2 removal by membrane absorption are discussed to conclude that CO2 capture efficiency is improved by increasing the flow rate, temperature, and absorbent concentration, reducing the gas flow rate, and selecting a mixed absorbent. We also explain the principles, processes and applications of CO2 membrane absorption.