The Relationship Between Coal Spontaneous Combustion Index Gases And The Changes Of Coal’s Microscopic Structure

As the primary basic energy of our country, coal has the characteristics of broaddistribution and huge reserve. But in the actual production, it often occurs to seriousspontaneous combustion which brings disastrous problems. Spontaneous combustionmay damage equipment and facilities, pollute the environment and cause enormous lossof the economy. Therefore, the index gases and the changes in coal structure can providetheoretical support for inhibiting spontaneous combustion of coal.Based on the theory of coal oxidation, experiments are taken to study of six kindsof different metamorphic grades of coal by combining basic sciences of heat transfertheory, organic chemistry, surface chemical physics and fractal theory. The experimentsmainly include: simulation of coal spontaneous combustion oxidation, SEM, mercuryintrusion, IR spectrum.The results of the experiments show that: in the coal oxidation process of lowtemperature, it mainly releases the gases of CO, CO2and CH4.When the temperature islower than110°C, it creates the nano-sized gas holes on the coal surface and the porestructures are simple. RH3perssad and R2CH2perssad are easily oxidized to peroxide(hydride peroxide) which is unstable. The CH4gas desorbs from the hole of coal, whichwas formed during the coal forming process. CO is created by decomposition of theperoxide (hydride peroxide). A part of CO2comes from the air and the other comes fromthe CO oxidation reaction. When the temperature is higher than110°C, the consumptionof coal increases, and the nano-sized gas holes turn to micron-sized gas holes and largegas holes. At the same time, the pore structures distribute discretely. The peroxide(hydride peroxide) created by RH3perssad and R2CH2perssad decomposes to stableperoxo-complex. As a result, the gas concentration of CO, CO2and CH4increases withsmall amount of olefin and alkyne (C2H6, C2H4, C3H8).