The Status of the Development Project for the 10 MWe-Scale Dry-Sorbent Carbon Dioxide Capture System to the real Coal-Fired Power Plant in Korea

摘要

Carbon dioxide capture system using dry regenerable K-based sorbents has been developed by Korea Institute of Energy Research (KIER) and Korea Electric Power Research Institute (KEPRI). In late 2009, we installed a 0.5 MWe-scale CO_2 capture pilot plant at Hadong coal-fired power plant in Korea. The pilot plant consists of a transport fluidized-bed carbonator for CO_2 sorption, cyclones for separating gas and solid, a bubbling fluidized-bed regenerator for sorbent regeneration, and a bubbling fluidized-bed sorbent cooler for sorbent cooling. The footprint of the pilot plant was 6 m × 10 m and the location of that was after Gas Gas Heater of the power plant. Until now, we have performed 100-day operation campaigns to find out the optimum operating conditions and the scale-up factors for 10 MWe-scale capture process. In the operation campaigns, several operating variables such as the moisture content in the flue gas, the solid hold-up in a carbonator, the solid circulation rate between a carbonator and a regenerator, and the reaction temperatures have been changed in order to investigate the effect of those variables on CO_2 capture and to derive the scale-up factors. It has been proved that above 80% of CO_2 removal for 50-hour continuous operation was possible at the optimum operating conditions. At the same time, we set the small scale unit which consists of two bubbling beds for carbonation and regeneration in order to investigate the effect of the H_2O partial pressure in the regenerator on CO_2 removal. The CO_2 removal in the carbonator increased as the steam mole fraction in the fluidization gas of the regenerator increased, although the content of H_2O, which is a product component in the regenerator, increased. We proved that the K_2CO_3·1.5H_2O has been formed in the regenerator by the XRD analysis and TGA analysis of the regenerated sorbent. The formation of K_2CO_3·1.5H_2O makes the carbonation reaction more active so that the CO_2 removal increased. It is also verified that high-concentrated CO_2 can be recovered when 100% of H_2O has been introduced as a steam phase to the regenerator. Thus, we also install the steam injection line to the regenerator in the 0.5 MWe-scale pilot plant. During 100-day operation campaign, we also tested high-concentrated CO_2 recovery by introducing 100% of H_2O as a steam phase to the regenerator.