Study on influence of different oxygen concentrations on coal spontaneous combustion characteristics based on difference method
Gas and heat are generated by oxidation,desorption and cracking in the process of coal low-temperature oxidation,which leads to the inaccurate influence of oxygen concentration based on gas and heat on the kinetics of coal-oxygen composite reaction.In this pa-per,a method that can eliminate these two paths was proposed.By using this method,the gas production and heat production characteris-tics of different coals were studied by temperature programmed experiments at different oxygen concentrations.Combined with micro-scopic characterization such as X-ray photoelectron spectroscopy(XPS)and specific surface area tester(BET),the intrinsic reasons for the microscopic changed in coal during oxidation process was analyzed.The experimental results show that the specific surface area of coal and the content of oxygen-containing groups in coal have great influence on the concentration and initial gas production tempera-ture,especially on CO2,and the difference method can effectively eliminate the influence of cracking and desorption and obtain an oxi-dation path that can reflect the essential characteristics of coal-oxygen recombination.Different oxygen concentrations have a great influ-ence on the gas production and heat production characteristics under the oxidation path.With the decrease of oxygen concentration,the gas production concentration and heat production rate gradually decrease.When the oxygen concentration is lower than 6％,the initial gas production temperature increases obviously,and the heat production rate is obviously inhibited,which seriously inhibits the further reaction between coal and oxygen,so it is difficult to occur coal spontaneous combustion.
coal spontaneous combustiondifferent oxygen concentrationsthermokineticsindicator gas
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