A conceptual evaluation of the use of Ca(OH)2 for attaining carbon capture rates of 99% in the calcium looping process

Calcium looping (CaL), typically capable of reducing CO 2 emissions by approximately 90%, is a technology well suited to capturing CO 2 emissions from a wide array of industrial processes. An approach in which Ca(OH) 2 is injected into the carbonator to increase the carbon capture efficiency of the CaL process to 99% was evaluated in this study using a one-and-a-half-dimensional reactor model. The effect of several key parameters was considered, including the injection flow rate, injection elevation, and the formation rate of CO 2 in the freeboard of the carbonator due to the combustion of char particles elutriated from the calciner. The main finding was that capture rates of 99% appear attainable, given that enough Ca(OH) 2 is injected and that the injection occurs at a suitable location, i.e., the sorbent is allowed sufficient residence time in the reactor. • Carbon capture rates of 99% appear attainable with a Ca(OH) 2 injection. • The elevation at which Ca(OH) 2 is injected significantly affects its performance. • CO 2 potentially formed in the carbonator is largely captured, given enough Ca(OH) 2 .