The effect of impurities in oxyfuel flue gas on CO2 storage capacity

Abstract Carbon capture and storage (CCS) is one of the major transformative technologies for reducing atmospheric CO 2 emissions from large CO 2 emitters where a large potential for geological CO 2 storage exists. CO 2 captured from the emitters contains various impurities, such as N 2 , O 2 , Ar, SO x , etc., and allowing these impurities to be stored together with CO 2 would reduce the cost of CO 2 capture. However, the impurities would have various undesirable effects on CO 2 storage. In this work we analyze the impact of non-condensable impurities N 2 , O 2 and Ar, which are present in large quantities in oxyfuel CO 2 streams, on CO 2 storage capacity of geological formations. A formula for measuring the impact of the impurities on CO 2 storage capacity is proposed, and based on the formula important insights are obtained. It has been shown that the impurities in oxyfuel flue gas reduce the structural trapping capacity for CO 2 by reducing the density of CO 2 , and the reduction of the trapping capacity is greater than the volume fraction of the impurities. Particularly, there is a maximum reduction of the storage capacity at a certain pressure, and this pressure changes with temperature. The strategy for alleviating the negative impact of the impurities has been discussed.