Development of Zirconium-Stabilized Calcium Oxide Absorbent for Cyclic High-Temperature CO2 Capture

A high-temperature regenerable CO2 absorbent, Zr-stabilized CaO, was prepared using the surfactant template-ultrasound synthesis method in this work. During 15 absorption/desorption cycles, it was found that Zr-stabilized CaO with a Zr/Ca molar ratio of 0.303 kept the most favorable stability and CO2 uptake capacity among the proposed Zr-stabilized samples. During multiple carbonation/decarbonation cycles, the incorporation of zirconium inhibited the agglomeration and sintering of CaO particles, thereby improving the absorbent durability. The effects of carbonation temperature (600-700 degrees C) and surfactant amount used in the preparation method on the performance of the proposed absorbent were investigated. The results showed that an excess of surfactant negatively affects the absorbent structural stability. Multicycle CO2 capture tests carried out between 600 and 700 degrees C showed that an increase in carbonation temperature improved the absorption capacity and durability of the proposed Zr-stabilized CaO absorbent. In summary, the results showed a superior prolonged stability of Zr-stabilized CaO as compared to pure CaO under severe operating conditions.