Study On The Influence Of Moisture On The Characteristics Of Low Temperature Oxidation Of Coal

There are many factors affecting the spontaneous combustion of coal.Moisture content is one of the most important factors that would affect the spontaneous combustion of coal.By studying the influence of moisture on the characteristic parameters of low temperature oxidation process of coal,it can provide the basis of predicting the spontaneous combustion of coal seams with different moisture contents and of precautions against fire.In this study,different moisture contents(the raw coal,5%,10%and 15%)of Sangshuping meagre coal were taken as study object.Experimental analysis was adopted to study the influence of moisture content on physical properties,free radical parameters,oxidation characteristics and thermal effect of coal at low temperature oxidation stage.The influence of moisture content on the parameters of coal and porosity were studied through the industrial and elemental analysis and true density experiment.To determine the variations in the physical properties of coal with the increase in moisture content.The influence of moisture content on the index gas,thermal weight loss,characteristics temperature were studied through the programmed temperature experiment and thermogravimetric experiment.Then the rules between coal oxidation characteristics and moisture contents,and also the relation between index gas and thermal weight loss were concluded.The influence of moisture content on the initial exothermic temperature,total heat release,periodic heat changes and activation energy were studied through the C80 thermal analysis experiment.It is concluded that moisture content takes great effect on the initial exothermic temperature and maximum heat release temperature.The total heat release firstly decreases then increases with the increase of moisture content.In the process of low temperature oxidation of coal,the variation of heat is divided into four stages:endothermic,slowly heat release,decrease of heat release rate,rapidly heat release.The variation of heat in each stage are different.In the rapidly heat release stage,the heat release is more than 85%which is the main cause of heat accumulation and temperature rise of coal.The influence of moisture content on the free radiation concentration and the g lactor were studiedthrough the EPR experiment.We can obtain the rules between free radiation parameters and moisture content,also the interaction between moisture content and free radiation.By comparingthe experiment results of low temperature oxidation characteristics oi coal with differenl moisture contents.It is concluded that there is a roughly proportional relationship between the variation of different characteristic parameters.The influence between different characteristic parameters are determined.