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 CO₂ emissions by approximately 90%, is a technology well suited to capturing CO₂ 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 CO₂ 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.