Experimental Study On Oxygen Adsorption Characteristics Of Coal At Low Temperature

Coal resource is abundant in China, but coal fire caused by severe spontaneous combustion badly threatens the production safety of coal mines .So the theoretical research on coal spontaneous combustion is practically important for coal production. The first step of coal spontaneous combustion is the contact of coal and oxygen, in which physical oxygen adsorption happens, then the chemical adsorption and chemical reaction happen , the energy generated in the process-heats the coal eventually leads to the coal spontaneous combustion . The physical oxygen adsorption of coal is the first stage of composite reaction between them, so the study on oxygen adsorption characteristics of coal at low temperature is extremely significant for theoretical research on coal spontaneous combustion.Based on the model of coal molecular structure and oxygen molecular structure, the mechanism on how coal physical adsorbs oxygen is analyzed, it is concluded that during the process of coal oxygen contact, non-aromatic structure in coal molecules are destroied firstly, alkyl side chain, bridge keys and oxygen containing functional group are the causes of coal-oxygen reaction and heat releasing . A lot of experiments have been carried out to analyze physical and chemical properties of coal samples. Based on that, using ZRJ– 1coal combustion character analyzer and coal-oxygen adsorption process analysis method, coal adsorption oxygen process characteristic curves under different experimental conditions are studied, the influences of different metamorphic degree, different particle size, different temperature and concentration of oxygen on coal-oxygen adsorption rules are concluded. Finally, based on the physical and chemical characteristics experiments on coal samples, how the internal factors such as coal character, metamorphic degree, porosity, functional groups affect coal-oxygen adsorption characteristics are analyzed.This research further reveals coal-oxygen adsorption mechanism,, it lays theoretical basis for coal spontaneous combustion mechanism study, development of quantitative evaluation and coal spontaneous combustion forecasting and resisting techniques.