Ca- and\nBa-Decorated CuO Oxygen Carriers for In Situ\nDechlorination in Chemical Looping Combustion

In\nthe chemical looping combustion of chlorine-rich biomass\nor\ncoal, a trace element, chlorine, will cause serious corrosion of oxygen\ncarriers and heat exchange equipment in boilers. To address this issue,\nwe design Ca- and Ba-decorated oxygen carriers to achieve two goals:\non one hand, reducing the concentration of chlorine-containing gases\nby in situ dechlorination; on the other hand, employing protective\nmaterials to preferentially bind with gaseous chlorine to safeguard\nthe active components of the oxygen carriers. Carefully designed experiments\nare conducted under simplified experimental conditions using 50 ppmv\nHCl-containing CH<sub>4</sub> to evaluate the intrinsic characteristics\nof oxygen carriers in terms of dechlorination efficiency and reactivity.\nThe results demonstrate that both the reaction performance and the\nchlorine-resistance performance of Ca–Cu and Ba–Cu composite\noxygen carriers are significantly improved. This is because (a) Ca\nand Ba preferentially form chlorides with HCl, effectively shielding\nthe active Cu component of the oxygen carrier from chlorine poisoning\nand (b) the specific surface area and pores of Ca/Ba-decorated oxygen\ncarriers are increased, which not only strengthens the heterogeneous\nreaction between oxygen carrier and combustible gas but also improves\nthe chemical looping combustion performance. The Cl-resistant oxygen\ncarriers, Ca–Cu and Ba–Cu, emerge as promising candidates\nfor the chemical looping combustion of fuels with high chlorine content.