Difference Study On The Whole Process Of Coal Spontaneous Combustion Between Tectonic Coal And Raw Coal

In order to study the differences between the spontaneous combustion process of tectonic coal and raw coal,and to determine the spontaneous combustion tendency of the two under the same experimental conditions,a series of tests and comparative analyses of the spontaneous combustion characteristics of tectonic coal and raw coal in the D,E and H coal seams of the flat coal group were carried out using a combination of experimental measurements and theoretical analyses,aiming to reveal the difference law of spontaneous combustion between the two.The results of the study are of great significance to the prevention and control of spontaneous combustion in tectonic coal seams.Using the results of industrial analysis and elemental analysis measurements,the chemical structure parameters of coal parts were calculated,and it was found that the ash content of the tectonic coal in the same seam was higher than that of the original coal,the n（H）/n（C）and n（O）/n（C）values were lower than that of the original coal,and the aromaticity and ring condensation of the tectonic coal were slightly higher than that of the original coal.The pore structure characteristics of the tectonic coal and the original coal were analyzed by low-temperature nitrogen adsorption experiments,and the pore structure was characterized by using fractal dimension,and the results showed that the pore connectivity of the tectonic coal was good,and the total pore volume and specific surface area were large compared with the original coal,which helped the coal-oxygen contact reaction.The fractal dimension D₁and D₂of the low-pressure and high-pressure zones of the tectonic coal are larger than those of the original coal,indicating that the surface morphology and internal pore structure complexity of the tectonic coal body are larger than those of the original coal.The differences in thermal analysis kinetic parameters,low-temperature oxidation gas products and oxygen consumption rate,and coal spontaneous combustion tendency index between the tectonic coal and the original coal during the whole process of spontaneous combustion were studied and analyzed through comprehensive thermal analysis experiments and programmed temperature rise oxidation experiments.The activation energy in the weight loss stage of high temperature pyrolysis and combustion is larger than that of the original coal;the curves of gas product change and oxygen consumption rate of the tectonic coal and the original coal in the low temperature oxidation process have intersection points,and the gas production and oxygen consumption rate of the tectonic coal are larger than those of the original coal before the intersection point temperature,but smaller than those of the original coal after the intersection point temperature.In summary,it shows that the reaction of tectonic coal in the slow oxidation stage is faster than that of raw coal,which can release heat and produce the sign gas earlier,while the reaction of raw coal in the violent oxidation stage is more violent and releases more heat than that of tectonic coal.Based on the measured experimental results parameters,combined with multiple linear regression theory and statistical principles,using gray correlation analysis to judge the correlation between the measured indicators and the spontaneous combustion propensity determination index,determined the ash,moisture,fractal dimension,C/H and apparent activation energy and other five indicators,using SPSS software to realize the principal component analysis,and finally established a regression analysis model with two principal components as the integrated independent variables.The model passed the significance test,covariance diagnosis and was statistically significant,and the accuracy of the proposed model was proved by comparing the calculated results of the model with the actual results.