The emission of pollutants during the coal combustion process has severely hindered the sustainable development of coal-firedpower plant, and it is urgent to explore efficient and ultra-low emission coal-fired power generation technologies. By oxidizing coal powderin supercritical water, the chemical energy generated is directly released into the water, producing a supercritical water/ CO2 compositeworking fluid that drives the steam turbine to work and generate electricity. After working with the working fluid, high concentrationCO2 can be directly recovered, achieving near zero emission combustion and power generation of coal. The effects of mineral removalon coal structure was studied by FTIR. The oxidation reaction characteristics of ashless Xichagou coal and the transformation of carbon,sulfur and nitrogen in supercritical water were studied under the conditions of the temperature region of 400-600 ℃ and oxidant equivalence ratio region of 1.0-1.4. The results show that demineralization by the acid alkali combined method has little effect on the structure ofXichagou coal, with shorter side chains of coal macromolecular fat and a slight increase in aromatic carbon content. The Xichagou deashing coal is oxidized in supercritical water, and the temperature and amount of oxidant have a significant impact on the coal conversion rate.The gas phase products are mainly CO2 during supercritical water oxidation, without producing NOx and SOx. Small amount of CO and H2are detected at temperatures lower than 500 ℃ . When the final reaction temperature exceeds 500 ℃ , the converted carbon is completelyoxidized to carbon dioxide. The conversion of carbon, nitrogen, and sulfur in coal increases with the increase of final temperature and theamount of oxidant. At the final reaction temperature of 550 ℃ and the oxidant being 1.4 times stoichiometric, the conversion rates of C, Nand S reach 97.08%, 94.52% and 94.41%, respectively.

张荣(1971—),女,天津人,研究员,博士。E-mail:zrbd@sxicc.ac.cn

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ZHANG Rong,ZHAO Xuechao,LIU Zhichang,et al.Element transformation rule of Xichagou ashless coal during the supercritical water oxidation process[J].Clean Coal Technology,2023,29(12):95-102.