Preparation and Performance of CuMn2O4 Composite Oxygen Carrier for Chemical Looping Oxidative Dehydrogenation of Ethane

Abstract

In chemical looping oxidative dehydrogenation (CL-ODH), an alkali metal molten shell material is typically employed to improve the reactivity of oxygen carrier. However, the existence of a molten shell necessitates reaction at a higher melting temperature than that of the shell itself, thereby increasing the oxygen-releasing temperature of the oxygen carrier. In this study, a novel oxygen carrier for ethane CL-ODH, CuMn₂O₄ promoted by non-molten shells of MnMoO₄ and SrMoO₄ was prepared and investigated. CuMn₂O₄ with high oxygen capacity releases lattice oxygen, while the adding Mo activates the C-H bond of ethane regulates ethylene selectivity. With CuMn₂O₄@MnMoO₄ as oxygen carrier, the ethane conversion and ethylene selectivity with oxygen carrier are 40.3% and 93.7%, respectively, and the maximum instantaneous yield of ethylene can reach 9.72 molC₂H₄/kg-cat/h at 700℃. Sr-modified CuMn₂O₄ oxygen carrier significantly increases the alkaline site on the surface, thereby enhancing the adsorption and desorption ability of ethane and ethylene. The prepared CuMn₂O₄@SrMoO₄ oxygen carrier obtained 44.6% ethane conversion and 88.94% ethylene selectivity at 700℃. The instantaneous yield of ethylene is as high as 9.32 molC₂H₄/kg-cat/h, and the oxygen capacity is 7.5 wt.%.