Search

Abstract: Korea Institute of Energy Research (KIER) and Korea Electric Power Research Institute (KEPRI) have developed the carbon dioxide (CO2) capture system using dry regenerable sorbents since 2002. The principle of the CO2 capture with regenerable solid sorbents is the reversible reaction between potassium carbonate and potassium bicarbonate in a thermal-swing process. Based on this reaction, we developed a bench scale unit (BSU) which treated 100 Nm3/h of flue gas in late 2006. The BSU consisted of a transport fluidized-bed carbonator, cyclones, a loop-seal, and a bubbling fluidized-bed regenerator. We have tested the BSU facility using a slip stream of the real flue gas from a coal-fired circulating fluidized bed combustor located at KIER in order to check the performance of CO2 removal, the stability of operation. The results showed that more than 80% of CO2 removal had been maintained during more than 50 hour continuous operation and its maximum reached at the 85% level. Those results indicated that the CO2 capture system using solid sorbents developed here could be applied to coal-fired power plant. In the meanwhile, we set the small scale unit which consists of two bubbling beds for carbonation and regeneration in order to investigate the effect of several operating variables on the CO2 removal. The performance of the small scale unit was investigated through the continuous operation with solid circulation under the same experimental conditions as the BSU facility. The CO2 removal of the small scale unit was reached at the 83% level with the inlet CO2 concentration of 10 vol.%. The CO2 removal increased as the water vapor content in the inlet flue gas stream, regeneration temperature, and solid circulation rate increased while it decreased as the gas velocity of the carbonator and carbonation temperature increased. It was found that the performance of the CO2 removal was very sensitive to the water vapor content in the inlet gas stream and the gas velocity of the carbonator (gas-solid contact time in the carbonator). The construction of 0.5 MW scale pilot plant based on the results of BSU at KIER has been finished in late 2009 at the Hadong Coal-Fired Power Plant, Korea Southern Power Company. The overall performance of pilot plant showed very promising and its CO2 capture performance reached at the 85% level. A 10 MW scale CO2 capture plant next development step after 0.5 MWe at the Hadong Coal-Fired Power Plant will be started to construct at the same site in late 2011. [Copyright &y& Elsevier]

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 SO x and NO x 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. [Copyright &y& Elsevier]