Thermodynamic simulation and experimental investigation of manganese oxide (MnOx) for integrated CO2 capture and conversion via chemical looping route
Yunlei Zhao, Bo Jin, Wenxing Yao, Zhiwu Liang
Abstract
Due to its high energy conversion efficiency, low economic cost and collaborative pollution control, chemical looping is emerging as a promising technology to deal with CO 2 emissions in energy and environmental fields. Based on the dual property of being carbonated and oxidized of MnO, the integrated CO 2 capture and conversion performance of manganese oxide is analyzed via chemical looping CH 4 -O 2 -CO 2 route. Thermodynamic calculation and process simulation indicate the equilibrium reduced solid is MnO instead of metallic Mn, which is consistent with material characterization. The gaseous oxygen released by MnO 2 is the prerequisite for its reactivity from thermodynamic analysis and is the effective step for MnO 2 -CH 4 reforming experiments. The CH 4 reforming performance of Mn 2 O 3 is limited from thermodynamic hierarchy and the lattice oxygen capacity of Mn 3 O 4 affects its reactivity with CH 4 . Mn 2 O 3 obtains the best partial oxidation reforming selectivity under higher operating temperature. The lattice oxygen is replenished with an obtained mole ratio of MnO 2 :Mn 2 O 3 as 0.12:0.03 through air oxidation under medium temperature conditions. The weight increment at CO 2 atmosphere indicates the 41.6 mol.% CO 2 capture ability of MnO. The CH 4 -O 2 -CO 2 cycle experiment proves the achievement in realizing the integrated CO 2 capture and utilization with one material via chemical looping route.