A thermogravimetric study of CoTiO3 as oxygen carrier for chemical looping combustion

Abstract

CoTiO3 perovskite was investigated as an alternative oxygen carrier for chemical looping combustion. The cyclical reduction and oxidation reaction were performed in TGA equipment. When the CoTiO3 particles were reduced, oxygen transfer capacity was maintained at 10.2 wt% during 10th cycles with 15% H2/N2 and 10.5 wt% with 15% CH4/N2. It was similar to the theoretical oxygen transfer capacity, 10.3 wt%. The maximum oxygen transfer rate was 0.015 mmol O2/g/sec during the reduction process. For 15% CH4/N2, the transfer rate was 0.03 mmol O2/g/sec which was twice that resulting from using hydrogen. From XRD and TPR results, CoTiO3 was transformed to Co/TiO2 and CoCx during reduction with hydrogen and methane, respectively. After all cycles, the particles were not agglomerated and appeared to be similar to its initial state. Conclusively, CoTiO3 could be a potential candidate as an oxygen carrier because CoTiO3 shows an improved oxygen transfer capacity and rate.