Abstract:
It is the basis for studying coal spontaneous combustion and its characteristics to obtain the relationship between kinetic parameters and temperature in the process of coal selfheating oxidation,which can’t be obtained by existing methods.The research on the testing approach of kinetic parameters during coal selfheating oxidation had been carried out.Based on the theory of thermal kinetic analysis,the model for calculating the kinetic parameters of coal oxidation with extents of conversion as the bond was derived,and the testing approach combining multiple heating rate experiments and constant temperature experiments was proposed.In order to determine the optimal experimental and computational parameters of the testing approach,the reaction time of coal self heating oxidation was introduced.By-using thermal analyzer and adiabatic oxidation device,the adiabatic oxidation experiments,multiple heating rate experiments and constant temperature experiments of three different ranks of coal under the condition of pure oxygen were conducted.According to the multiple heating rate experiments results,the influence of heating rates on the global mass variation in different stage was analyzed respectively,and the maximum heating rate was determined.Within this range of heating rate and derived calculation model,the influence on kinetic parameters with different heating rates and extent of conversion step length was analyzed.It was found that the extent of conversion step length mainly affects the density of the kinetic parameters,while the combination of heating rates have little effect on the results of kinetic parameters.Based on the adiabatic oxidation experiment results and considered the time cost,the optimal experimental and computational parameters for obtaining the coal self heating oxidation kinetic parameters were determined,and their accuracy and applicability were verified.The results showed that when the heating rates are 0.2,0.5,1.0,2.0 ℃/min and the extent of conversion step length is 0.03,the self heating kinetic parameters of coal oxidation obtained from the experiment are closest to the reality.