Characterization of a Marl-Type Cement Raw Meal as CO2 Sorbent for Calcium Looping.

Abstract

The use of cement raw meals as sorbent precursors for CO2 capture can reinforce the synergies between the cement production process and calcium looping CO2 capture technology. In this work, we measure the CO2-carrying capacity of different calcined samples of a particular marl, which were obtained under very different calcination conditions and setups (a thermogravimetric analyzer, a drop tube furnace, and an industrial calciner). We find that the reactivity toward CO2 of these calcined materials displays a strong sensitivity to the calcination conditions, in particular to calcination time. A pronounced competition between the belite (Ca2SiO4) formation reaction and the formation of free CaO needed for CO2 capture is detected. As the calcination of the raw meal approaches flash conditions (i.e., >90% calcination conversion in less than 10 s), the belite formation is shown to be minimized, leading to sorbents with CO2-carrying capacities of approximately 0.4 mol CO2/mol CaO.