Research On Reaction Characteristics Of Active Groups And Free Radicals In Process Of Coal Spontaneous Combustion

Coal spontaneous combustion is one of the five mine disasters.In recent years,the coal spontaneous combustion mechanism has done a lot of research and put forward many reaction models,but for the overall reaction in coal active groups and free radicals are still not deep.Based on this,the coal spontaneous combustion process of active groups and free radical reaction was investigated.Four gases of CO,CH4,C2H4,and C2H6 of 1# lignite,2# candle coal,3# gas coal,4# coking coal and 5# anthracite coal were faster and more free from coal spontaneous combustion under oxygen by programming temperature-gas chromatography.CO was produced at the whole low temperature,the relationship between CH4,C2H4 C2H6 and the degree of metamorphism of coal samples.Regenerative period,self heat period and spontaneous combustion period were confirmed by characteristic temperature point of index gas,the self reaction of the active group in coal was further confirmed.Linewidth(?H),g factor and free radicals concentration(Ng)of coal samples were studied under oxygen and nitrogen by using electron paramagnetic resonance(ESR).?H was associated with the degree of metamorphism.The free radical species(g factor value)in coal was generally slow with the change of temperature under oxygen.The change of the value of g factor was larger under nitrogen.Ng of coal samples has a relationship with 5# anthracite coal>4# coking coal>3# gas coal>2# candle coal>1# lignite.In situ FTIR facility was used to measure the infrared spectrum of coal at 30~200? under oxygen and nitrogen,and analysis of the variation of peak area of-C=O-?-CH3?-CH2-CH3?-CH=CH2 groups under oxygen and nitrogen for five kinds of coal samples with different metamorphic degrees,it was found that the active groups of coal in three stages of coal spontaneous combustion can produce different kinds of gas in combination with gas chromatography and ESR.Based on the above experiments,the reaction model of active group and free radical in different stages of coal oxidation were deduced preliminarily.