Stabilizer-coated combined Ca/Cu pellets with controllable particle sizes for the Ca/Cu chemical loop

The fabrication of high-performance combined Ca/Cu pellets is crucial for advancing the Ca/Cu chemical loop, wherein the reduction of CuO facilitates the required heat for CaCO3 decomposition. However, the CO2 sorption performance of combined Ca/Cu pellets experiences a swift deterioration, presenting a notable obstacle. Herein we reported a two-step synthesis approach to prepare stabilizer-coated combined Ca/Cu pellets with controllable particle sizes. To begin, combined Ca/Cu pellets were prepared, which had varying particle size ranges (ranging from 120 to 390 mu m, 230 to 480 mu m, 330 to 670 mu m, and 600 to 980 mu m). In the first cycle, the particle sizes of these pellets decreased, leading to an increase in their CO2 sorption capacity from 0.169 to 0.208 gCO2/g(sorbent). Nevertheless, all combined Ca/Cu pellets exhibited a decrease in their ability to absorb CO2 during ten cycles, leading to a reduction of around 35 % in their initial CO2 sorption performance. Afterward, diverse stabilizer layers (Al2O3, MgO, or Y2O3, with a corresponding mass ratio of 7.5 wt%, respectively) were applied to the combined Ca/Cu pellets. The combined Ca/Cu pellets coated with Y2O3 exhibited superior performance in capturing CO2 compared to the counterparts coated with Al2O3 or MgO. After 30 cycles, Y2O3-coated combined Ca/Cu pellets, containing similar to 12.5 wt% Y2O3, exhibited a CO2 sorption capacity of 0.145 gCO2/g(sorbent), retaining 45.0 % of its initial CO2 sorption performance.