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The paper proposed a design scheme of oxidation kinetics testing equipment for coal spontaneous combustion tendency on the basis of oxidation kinetics testing method of coal spontaneous combustion tendency, and introduced working principle of the equipment, selection of gas source, design of supply equipment of standard gas, building of coal sample response, type selection of gas analyzing instrument and design of control and displaying board. The experiment showed that the equipment can realize functions of automatic sampling, automatic analysis and on-line collection, and the experimental result is repeatable excellently, which verifies stability of the equipment.

With the expansion of the scale of coal mining, the safety problems caused by the reburning of coal are becoming more and more serious. In this paper, the pyrolysis characteristics of gas coal and the exothermic characteristics of reoxidation of residues were studied by using a synchronous thermal analyzer. The functional groups of pyrolysis residues were tested, and the group content and characteristic structural parameters were calculated based on quantum chemistry method. The results show that with the increase of pyrolysis temperature, Volatile maximum separation rate (Vmax) and the change in the residual weight of the coal sample (ΔWvp) increase. The increase of temperature will lead to the decrease of hydroxyl and aliphatic hydrocarbon content in coal, and the increase of aromatic hydrocarbon. With the deepening of pyrolysis, the ignition point temperature of coal samples decreases first and then rises, the combustion intensity and combustion concentration are strengthened. The pyrolysis results show that 462.8°C is the critical temperature for the transition during pyrolysis. The ignition point of the residue is less affected by the pyrolysis conditions, and the ignition temperature of the raw coal and the pyrolysis residue varies within 330.57°C–334.98°C. [ABSTRACT FROM AUTHOR]

Aiming at the complexity of coal structure and reaction, based on the analysis of active group species, structure and its transformation characteristics in coal reaction, the paper comprehensively constructed the active structural unit in the process of coal spontaneous combustion for the first time. Using the frontier orbital theory and quantum chemical calculation to analysis the complete reaction path, activation energy and the heat release of electron transfer in reactions of the active site, the 13 elementary reaction were obtained. The order and relationship of the reactions in coal spontaneous combustion was also built. Based on the research results, the coal oxidation dynamics theory was presented in the paper, which is a chemical chain cycle caused by oxygen with low activation energy, and converts the coal native structure to carbon free radicals releasing the gaseous products. The reaction mechanism of heat and products was illustrated in the oxidation dynamics theory of coal spontaneous combustion. The theory was successfully applicated in categorizing the spontaneous combustion tendency of coal and developing highly-effective chemical inhibition technology to prevent coal spontaneous combustion. [ABSTRACT FROM AUTHOR]