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

Abstract

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 °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 °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.

Improving the stability of synthetic CaO-based CO 2 sorbents by structural promoters

“…Therefore, although Ca-Al-80 has a higher initial CO 2-capacity due to the higher CaO concentration in its structure, it also demonstrates higher reduction in sorption rates during the first cycles leading to the same final sorption capacity with CaAl-66. This implies that it is necessary to have an adequate amount of structural promoter in the sorbent in order to maintain the structure integrity of CaO in the material during multiple sorption/desorption cycles [51,[76][77][78].…”

A highly efficient CaO-based CO2 sorbent prepared by a citrate-assisted sol–gel technique

“…Researchers focused mainly on improving the structure and thermal resistance of CaO either by introducing a metal oxide stabilizer phase or exploring different Ca-precursors leading to improved properties. An extensive range of metal oxide stabilizers was used to enhance the stability of CaO, including Zr, Al, Ti and Si oxides [8][9][10][11][12][13][14][15][16]. A key point toward large-scale application of any CO 2 sorbent is its production cost.…”

Durability of CaO–CaZrO3 Sorbents for High-Temperature CO2 Capture Prepared by a Wet Chemical Method

“…The overall performance of the present powders is superior in terms of initial uptake capacity and multicycle durability when compared to several other Zr modified CaO powders produced by wet chemical routes 17, 19 . The new powders presented here show negligible decay in CO 2…”

“…Radfarnia and Iliuta produced Zr-modified CaO sorbents using a surfactant templated ultrasound synthesis method 19 . The best powders, n Zr :n Ca =3.03:10 exhibited a drop in molar conversion ratio from ~32 % in cycle 1 to ~24 % in cycle 15.…”