Research on free radical reactions during coal heating process under poor oxygen conditions
Addressing the issue of coal spontaneous combustion disasters caused by low-temperature oxidation of coal bodies,the chan-ges in free radical concentration,g-factor,and line width during the heating process of coal samples at different oxygen concentrations were measured using an electron spin resonance spectrometer.The free radical reaction characteristics of coal samples under poor oxygen conditions were studied.The experimental results show that the relative concentrations of primary free radicals in the initial oxidation stage of the three coal samples are:anthracite＞bituminous coal＞lignite,and the relative growth rates of free radical concentrations at 0％,10％,and 21％oxygen concentrations are calculated as follows:lignite＞bituminous coal＞anthracite,indicating that the free radi-cal reaction of lignite is more intense under oxygen poor conditions.The g-factor of the three coal samples increases with the increase of temperature,and at the same temperature,the g-factor is directly proportional to the oxygen concentration and inversely proportional to the degree of coal sample metamorphism.During the oxidation process,the line width of lignite is higher than that of bituminous coal and anthracite,but the decrease in line width of lignite is smaller than that of bituminous coal and anthracite.The line width of the three coal samples is less affected by oxygen concentration.The free radical reaction characteristics of coal with different degrees of metamorphism obtained from experiments under oxygen deficient conditions are of great significance for studying the free radical reaction mechanism of coal spontaneous combustion.
coal spontaneous combustionpoor oxygen conditionslow temperature oxidationfree radicals
万方数据
维普
