Experimental study on CO 2 capture conditions of a fluidized bed limestone decomposition reactor

Abstract

In this study, the decomposition conditions of limestone particles (0.25–0.50 mm) for CO 2 capture in a steam dilution atmosphere (20–100% steam in CO 2) were investigated by using a continuously operating fluidized bed reactor. The results show that the decomposition conversion of limestone increased with the steam dilution percentage in the CO 2 supply gas. At a bed temperature of 920 °C, the conversions were 72% without steam dilution and 98% with 60% steam dilution. The conversion was 99% with 100% steam dilution at 850 °C of the bed temperature. Steam dilution can decrease not only the decomposition temperature of limestone, but also the residence time required for nearly complete decomposition of CaCO 3. The hydration and carbonation reactivities of the CaO produced were also tested and the results show that both the reactivities increased with the steam dilution percentage for decomposing limestone.