Study on influence of coal structure on spontaneous combustion tendency

This paper focuses on the analysis of the influence of coal structure on the spontaneous combustion propensity of coal and the contribution degree of each factor to the spontaneous combustion propensity. Five representative coal samples with different degrees of metamorphism were selected, and the oxidation kinetics was carried out by temperature programmed-gas chromatography. The test determines the comprehensive judgement index of spontaneous combustion propensity of coal.Scanning electron microscopy, specific surface area, and pore size analyzer were used to carry out SEM test and low temperature nitrogen adsorption test to detect the macro structure of coal. The main functional groups of coal microscopic molecules were analyzed by Fourier transform infrared spectroscopy and OMNIC peak separation software.The analysis used gray correlation analysis method to find out the correlation degree between each factor and the spontaneous combustion propensity and classified it.The SPSS software and the multivariate statistical principle were used to establish the multi-regression analysis model of coal spontaneous combustion propensity. The model was tested, the coefficients were analyzed, and the normal map was analyzed. The results show that with the increase of metamorphism, the content of main functional groups changes obviously, macro pores and fissures decrease, the structure of coal body becomes compact, the molecular stability increases, the propensity of spontaneous combustion of coal decreases, and the proportion of micro pores is most correlated with the spontaneous combustion propensity of coal. Through the grey correlation analysis and multiple regression analysis, a reliable multivariate regression analysis model of coal spontaneous combustion propensity was established, and the key factors affecting the spontaneous combustion propensity were found out,and the linear relationship between spontaneous combustion tendency and part test data of coal is revealed.