Effect of TiO_2 dopant on CO_2 capture performance of Na_2CO_3/Al_2O_3
摘要
The control of CO2 emission by using sodium-based solid sorbents is receiving attention increasingly because of low reaction temperature and low energy consumption. However, there is a primary drawback for it, i.e. low reactivity with CO2 during sorption process. So, a modified sodium-based solid sorbent, Na2CO3/NaHCO3 supported on alumina and modified by TiO2, was proposed for CO2 capture and characterized by SEM, XRD and TG. The results indicate that TiO2 is stable in whole range of operation temperature of capturing CO2 process and after use there is no formation of Ti compounds except TiO2. More importantly, after dopping TiO2 the CO2 capacity of the sorbent increases and its reaction rate with CO2 goes also up. The reaction products are NaHCO3 and Na5H3(CO3)4. However if too much TiO2 was doped, block of sorbent microstructure could take place, leading to unfavourable effect on the CO2 capture process.