Effect of contaminants from flue gas on CO 2 sequestration in saline formation

SUMMARY Deep saline aquifers are reported to have the largest estimated capacity for CO 2 sequestration. Most geochemical studies on CO 2 storage in saline formations are focused on the interactions of pure CO 2 and do not consider the potential impacts of contaminants such as SO 2 found in typical post‐composition flue gas streams. This paper reports on results of a combined CO 2 –co‐contaminant–brine–rock experimental and a simple modeling study of the potential impact of flue gas contaminants on saline formations. Chemical reactions of the sandstone from Mount Simon formation exposed to CO 2 mixed with other gas species under sequestration conditions were studied (i.e. solid material — representative Mount Simon sandstone; liquid — synthetic Illinois Basin brine; T and P — 50 °C, 110 bar; gas composition — 1% SO 2 , 4% O 2 , 95% CO 2 ). The experimental study indicates that the co‐injection of 1% SO 2 would lead to substantially reduced brine pH due to the formation of sulfuric acid and the formation of bassanite (major) and anhydrites. Preliminary equilibrium computational modeling yielded similar results. Copyright © 2013 John Wiley & Sons, Ltd.