Investigation on the effect of transition metal chloride on anthracite combustion

In recent years, the international community has paid more attention to environmental pollution and climate change caused by the use of fossil fuels. How to strengthen the efficient use of coal has become a problem that must be solved. This work aims to study the effect of transition metal chlorides (CuCl2, FeCl3 and ZnCl2) on the promotion of burn off reaction and the improvement of anthracite heat release efficiency by using TG-DSC, FTIR and EPR. The effect of adding three transition metal chlorides on oxygen absorption and heat release of anthracite was studied by TG-DSC. Results show that the addition of CuCl2, FeCl3 and ZnCl2 can promote the burn off reaction, thereby increasing the heat release efficiency of anthracite. Specifically, the addition of CuCl2 increases the heat release of the anthracite by 15%. FTIR was used to study the structural changes during the heating process of raw coal and coal with transition metal chlorides. Results show that CuCl2 can effectively promote the direct pyrolysis of aliphatic functional groups and reduce the formation of oxygen-containing functional groups. In addition, the mechanism of CuCl2 promoting the burn off reaction was studied by ESR spectra analyses. It is found that the free radical concentration of the coal with CuCl2 is higher than that of the raw coal, which indicating that the burn off reaction is an oxidation reaction dominated by free radical. This work may have a guiding significance for the efficient utilization of anthracite.