Correlation Research On Microscopic Pore Structure Characteristics And Combustion Characteristics Of Coal

China is the big country of coal produce and consume in the world,at thesame time, coal spontaneous combustion disaster occurs frequently. Coalspontaneous combustion lead to the loss of resources, environmental pollutionand threaten the safety production.As spontaneous combustion of coal is affectedby many factors and it’s a complex dynamic process, people doesn’t know itsmechanism.Through experiment and theoretical analysis to study the relationshipbetween pore structure and coal spontaneous combustion characteristic,it’smeaningful for spontaneous combustion of coal.The variation trends of the coal with different metamorphic grade areobtained by synchrotron X-ray microtom ography and nitrogen adsorption.Internal coal pore shape is diversiform and irregular,theirs shapes like snow andconnected into a net,coal’s connectivity are obvious differences; Pore volume’sfeature is concave curve with different metamorphic grade,bituminous coal porevolume is lowest, lignite’sislargest,themainpartoflowdegreeofmetamorphismof coal are big pore and middle pore,high degree of metamorphism of coal is not,medium metamorphic degree of coal is uniform; Specific surface area of low-middle coal change is small, Specific surface area with middle turn to high degreerapid increase the microporous pore and small pore accounted for99%of whole area; The average pore diameter with the increase of metamorphic degree decr-eases.The pore of coal have fractal characteristics by fractal study,Comprehens-ive fractal dimension is obtained by volume percentage weight of each porediameter range,the relationship between comprehensive fractal dimension andmetamorphic grade of coal is high-low high concave curve.This paper studied the different metamorphic degree of coal spontaneouscombustion characteristics by chromatographic method of fluid oxygenadsorption and experiment of coal spontaneous combustion similar simulation.Inhaled oxygen change like an concave curve, SH>XM>SD>XS>PS>ZZ. Alongwith temperature increased of the coal low temperature oxidation process, oxygenconcentration is on the decline,the inflection point temperature of lowmetamorphic coal is lower than middle metamorphic coal’s, with the temperatureincreases, oxygen consumption rate of coal index increased, oxygen consumptionrate of low metamorphic coal greater than high metamorphic coal’s under sametemperature; Crossing point temperature increases linearly with the metamorphicdegree deepening; Oxidation kinetics of the comprehensive judgement indexincreases linearly with the metamorphic degree deepening.In a word, the lowerdegree,the stronger ability of coal spontaneous combustion oxidation.Based on the research of the relationship between pore structure and coalspontaneous combustion characteristic,the influence of pore structure to oxygenintake is the largest. Fractal dimension is positively related to the oxygen quantity,pore volume plays a leading role for inhaled oxygen under low-middlemetamorphic coal,the greater volume, the greater oxygen quantity. Specificsurface area plays a leading role for inhaled oxygen under middle-highmetamorphic coal, the greater area, the greater oxygen quantity. Pore structure ofcoal has a certain influence to the ability of spontaneous combustion of coal. It’sdivide into two inversely stages, oxidation kinetics of the comprehensive judgement index reduces with the increase of pore volume and fractal dimensionin low-middle metamorphic coal, it is easily to coal spontaneous; On thecontrary,oxidation ability of coal reduces with the increase of pore structureparameters in middle-high metamorphic coal.