Sour compression process for the removal of SO_x and NO_x from oxyfuel-derived CO₂

Coal-fired power stations under oxyfuel combustion produce a raw CO 2 product which contains impurities such as water, oxygen, nitrogen and argon from excess oxygen and air leakages. There are also acid gases present, such as SO3, SO2, HCl and NOx produced as by-products of combustion. These acidic impurities will need to be removed from the CO2 stream before it is introduced into the pipeline to prevent corrosion and comply with possible regulations. There may also be stringent requirements on purity, particularly for applications such as enhanced oil recovery. A novel compression method of producing NOx-free, SO2-free CO2 was proposed in GHGT-8 [1-6] where SO 2 and NOx are removed as H2SO4 and HNO3 respectively by compression and water contact of the flue gas. At GHGT-9, initial experimental results were presented using actual fluegas via a sidestream from Doosan Babcock's 160 kW coal-fired oxyfuel rig, showing the feasibility of the process eliminating 99% SOx and 90% NOx compounds. In this paper, we report on the effects of pressure, temperature, residence time and presence of water in a laboratory scale apparatus using synthetic flue gas. 2011 Published by Elsevier Ltd.