Preparation of High Sorption Durability Nano-CaO–ZnO CO2 Adsorbent

ZnO was doped into nano-CaO adsorbents to increase the sorption durability in the calcium looping (CaL) process. The preparation of a nano-CaO–ZnO adsorbent was studied in detail by varying the ZnO additive amounts and thermal pretreatment conditions. Also, the performance of the nano-CaO–ZnO adsorbent was evaluated under different CaL operation conditions. The results showed that the carbonation conversion of CaO in the adsorbent was stably kept as 57.4% after 15 cycles when the optimum values of the molar ratio of CaO to ZnO was 8, thermal pretreatment temperature and time were 850 °C and 1 h, respectively, and the carbonation and regeneration temperatures were 700 and 750 °C, respectively. The anti-sintering performance of ZnO was close to that of ZrO2 and TiO2 and better than that of MgO and Al2O3. The reason for the high durability of the nano-CaO–ZnO adsorbent was that low thermal expansibility dopant ZnO, could promote the recurrence of nano-CaO grains, leading to self-reactivation in the CaL process.