Long-term operation of carbon dioxide capture system from a real coal-fired flue gas using dry regenerable potassium-based sorbents

Abstract

Korea Institute of Energy Research (KIER) and Korea Electric Power Research Institute (KEPRI) have been developing a CO2 capture technology using dry sorbents. The CO2 removal in dry sorbent CO2 capture system consists of two reactors for carbonation and regeneration. We used dry sorbent manufactured by spray-drying method contains potassium carbonate, which was supplied by KEPRI in order to investigate the sorbent performance in continuous operation mode with solid circulation between a fast fluidized bed type carbonation reactor (13.5 m tall pipe of 0.075 m i.d.) and a bubbling fluidized bed type regeneration reactor (2 m tall bed of 0.25 m i.d.). We used the real flue gas from 2MW coal-fired circulating fluidized bed combustor to check possibility of deactivation of dry sorbent by contaminants such as SOx and NOx in the real flue gas for the 100 Nm3/hr of flue gas treatment facility. The residence time of the dry sorbents was about 3 seconds and 15 minutes in the carbonation reactor and the regeneration reactor, respectively. The CO2 removal during 2 hrs in the whole experiments and the average CO2 removal was above 70%. From the experiment, it was revealed that the removal of heat of sorption in the carbonation reactor was important to increase CO2 removal. During the experiments continuous and smooth operation were accomplished with solid circulation between two reactors. These results indicate that CO2 capture process using potassium carbonate solid sorbent is applicable for CO2 capture in the coal-fired flue gas.