Carbon dioxide capture from a real coal-fired flue gas using K-based solid sorbents in a 0.5 MWe-scale test-bed facility

Abstract

Three kinds of K2CO3-based solid sorbents was tested in a 0.5 MWe-scale test-bed, integrated with a real coal fired power plant. The test-bed, consisting of a fast fluidized-bed carbonator, a bubbling fluidized-bed regenerator and a bubbling fluidized-bed sorbent cooler, was installed beside a Unit #3 in a Hadong coal-fired power plant. The components of K2CO3-based solid sorbents were an active reaction component of K2CO3 for CO2 sorption with the supports including Al2O3 for mechanical strength. Three different solid sorbents were differentiated depending on the amount of an active component (35 wt.% or 40 wt.%) and the different composition of Al2O3 (alpha alumina or gamma alumina). CO2 capture performance was evaluated in a test-bed at the same operating conditions for three kinds of solid sorbents, which showed better CO2 capture performance with the solid sorbent with 40 wt.% than that with 35 wt.% one. Better performance with alpha alumina as a support was obtained as compared to that with gamma alumina. Additionally, the effect of water vapor to CO2 mole ratio in a flue gas, solid hold-up in a mixing zone of a carbonator and the regeneration temperature on the CO2 capture performance was analyzed. The experimental results in a test-bed was confirmed by analyzing the solid samples of after-carbonation and after-regeneration. The CO2 capture efficiency in the carbonator was varied from 60 to 90% whereas the dynamic sorption capacity of the sorbents from 3–7 wt.% in relation with the kinds of sorbents and the operating conditions. All the experimental data was used to design the 10 MWe-scale pilot plant beside a Unit #8 in a Hadong coal-fired power plant.