Wet mixing combustion synthesis of CaO-based sorbents for high temperature cyclic CO2 capture

• We propose a wet mixing combustion synthesis method to prepare CaO-based sorbent.
• The precursors of the sorbent can be derived from cheap materials.
• The optimal molar ratio of calcium to magnesium is 2 during preparation.
• The optimal molar ratio of fuel to metal oxides is 0.5 during preparation.
• The new sorbent shows relatively stable performances during cyclic reactions.

CaO-based sorbents are considered suitable candidates for cyclic CO2 capture at high temperatures. However, the CO2 capture capacities of natural CaO-based sorbents decrease sharply after only a few cycles. This paper presents a novel wet mixing combustion synthesis to improve the cyclic CO2 capture performance of CaO-based sorbents. Results show that preparation conditions significantly affected the cyclic performance of the sorbents. The optimal molar ratios of calcium to magnesium and fuel to metal oxides were 2 and 0.5, respectively, for the preparation process. The wet mixing combustion synthesis did not show the highest CO2 capture capacity in comparison to the sol–gel combustion synthesis, however, the proposed method is still valid due to the low cost of the materials used. The sorbent prepared by the new method could achieve relatively stable cyclic CO2 capture behavior, and showed a porous microstructure that can be maintained during cyclic reactions. The capture capacity of the sorbent obtained a 0.4 g CO2/g sorbent after 50 cycles.