Comparison of metallic oxide, natural ore and synthetic oxygen carrier in chemical looping combustion process

Abstract

As one of clean coal combustion ways, chemical looping combustion (CLC) showed high CO2 capture efficiency with lower energy penalty. But these processes were limited by the low reaction rate between oxygen carriers (OCs) with coal char. This study evaluated the performances of Cu-based OCs with coal in in-situ gasification chemical-looping combustion (iG-CLC) and chemical-looping with oxygen uncoupling (CLOU) process. CuO modified by iron ore and chrysotile were employed as OCs which the addition of chrysolite improved the char gasification and iron ore enhanced the stability of CuO at high temperature. Results showed that CuO supported by ores (chrysolite and iron ore) had better H2 and CO conversion under H2O atmosphere than CuO and iron ore. Chrysolite decorated CuO can convert almost all H2 to H2O at 850 °C. Synthetic OCs showed better stability and high temperature tolerance during 10 redox cycles.