Simultaneous CO2 capture and heat storage by a Ca/Mg-based composite in coupling calcium looping and CaO/Ca(OH)2 cycles using air as a heat transfer fluid

The simultaneous CO2 capture and heat storage performances of the Ca/Mg-based composite prepared from carbide slag and dolomite in a process coupling calcium looping and CaO/Ca(OH)(2) heat storage using air as a heat transfer fluid were investigated. In the coupling process, the spent CaO-based material experiencing multiple CO2 capture cycles was employed in the CaO/Ca(OH)(2) heat storage process, and then the cycled material was again used to capture CO2. When the mass ratio of CaO/MgO in the composite is 90 : 10, it exhibits the highest heat storage capacity of 0.53 mol mol(-1) and a heat storage density of 0.90 GJ t(-1) after 30 heat storage cycles. The adverse effect of CO2 in air as the heat transfer fluid on CaO/Ca(OH)(2) heat storage capacity is overcome by the introduction of calcium looping cycles. By introducing a calcium looping cycle after the 10th and 20th heat storage cycles, the subsequent heat storage capacities of the composite are improved by 31% and 57%, respectively. The CO2 capture reactivity of the composite is also promoted by the introduction of heat storage cycles. Therefore, the simultaneous efficient CO2 capture and heat storage using the Ca/Mg-based composite is achieved in the process coupling calcium looping and CaO/Ca(OH)(2) cycles.

Automated summary

The study shows that simultaneous efficient CO2 capture and heat storage performance can be achieved by using Ca/Mg-based composites in a process coupling calcium looping and CaO/Ca(OH)2 cycles. The adverse effect of CO2 in air on CaO/Ca(OH)2 heat storage capacity is overcome by introducing calcium looping cycles, which also improves the subsequent heat storage capacities of the composite. Introducing heat storage cycles also promotes the CO2 capture reactivity of the composite.