TY - THES

T1 - Experimental Investigation on the Performance of Transition Metal Chloride in Catalyzing Coal Combustion

AU - Wei, Hongyi

N1 - embargoed until null

PY - 2021

Y1 - 2021

N2 - 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 coal 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 coal was studied by TG-DSC. Results show that the addition of CuCl2, FeCl3 and ZnCl2 can inhibit the oxygen absorption of coal and promote the "burn off" reaction, thereby increasing the heat release efficiency. Specifically, the addition of CuCl2 increases the heat release of the coal by 15 %. Based on the data of TG-DSC experiment, the kinetic parameters of samples in the "burn off" reaction stage are further calculated. After adding CuCl2, the activation energy at this stage will be significantly reduced, only a quarter of that of the raw coal, indicating that CuCl2 can effectively promote the combustion of the coal. 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 EPR 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. The research results in this study are of great significance to the efficient and clean utilization of coal.

AB - 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 coal 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 coal was studied by TG-DSC. Results show that the addition of CuCl2, FeCl3 and ZnCl2 can inhibit the oxygen absorption of coal and promote the "burn off" reaction, thereby increasing the heat release efficiency. Specifically, the addition of CuCl2 increases the heat release of the coal by 15 %. Based on the data of TG-DSC experiment, the kinetic parameters of samples in the "burn off" reaction stage are further calculated. After adding CuCl2, the activation energy at this stage will be significantly reduced, only a quarter of that of the raw coal, indicating that CuCl2 can effectively promote the combustion of the coal. 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 EPR 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. The research results in this study are of great significance to the efficient and clean utilization of coal.

KW - transition metal

KW - burn off

KW - heat release

KW - activation energy

KW - free radical

KW - transition metal

KW - burn off

KW - heat release

KW - activation energy

KW - free radical

M3 - Master's Thesis

ER -