Study on Stage Determination Theory and Classified Early Warning Method for Spontaneous Combustion of Coal

Author:Fei Jin Biao

Supervisor:wen hu


Degree Year:2019





Coal spontaneous combustion is the main cause of mine fire,which has always threatened coal mine safety.’IThe spontaneous combustion of coal is a very complex dynamic process.Its formation and development are spontaneous,slow,and dynamically changing exothermic,calorific,and warming processes that cause combustion.To determine the coal spontaneous combustion stage and achieve the coal spontaneous combustion classification warning is the key to prevent coal spontaneous combustion.In this paper,based on the determination of coal spontaneous combustion stage and classification warning,the research is carried out through experimental test,theoretical analysis and field test.According to the characteristics of coal spontaneous combustion temperature,the corresponding relationship between temperature and gas is established by using the parameters of single and composite indexes,weight ratio and weightless rate of coal spontaneous combustion process.Eight characteristic temperatures were determined;Based on the coal spontaneous combustion molecular structure model,the coal molecular group changes in the coal spontaneous combustion process are analyzed by coal oxidation Kinetics theory,quantum chemistry theory and similar theory.The types of active groups of coal molecules,the priority order of reaction channels and the active order of active groups on coal surface were studied.Based on the analysis of coal spontaneous combustion group mutation theory,six characteristic temperatures were selected,and the coal spontaneous combustion process was divided into seven stages.According to the coal spontaneous combustion early warning,the law of oxidation gas and pyrolysis gas generation during coal spontaneous combustion was found,the coal spontaneous combustion marker gas and multiple parameter indexes were studied,and the expression method of CO gas concentration in the oxygen concentration range was found,and six coal spontaneous combustion indexs were optimized.They are CO,O2,CO/ΔO2,C2H4,C2H4/C2H6 and C2H2.For easy self-combustion coal,the field test is carried out,and the successful connection between the experimental data and the field test data is achieved,the coal spontaneous combustion index was quantified,an early warning system for coal spontaneous combustion was established,and a classification warning method for coal spontaneous combustion was improved.This paper gives the division basis for the threshold,fire signs and fire of coal spontaneous combustion in the Coal Mine Safety Regulations,and provides guidance for the transition from passive control to active prevention.