Relation between free radicals concentration and gas products in process of coal low temperature oxidation

Abstract：Using low temperature oxidation equipment of the coal and electron paramagnetic resonance（EPR）,researched the variation of gas products and redical concentration of lignite,gas coal,gas-fat coal and anthracite at different low temperature oxidation temperature and opened out the laws of low-temperature oxidation of coal self-heating in such a way of the combination of macro and micro.The results show that the oxidized molecular side of the coal is broken that come into being CO gas,C2H4 gas and free radicals,and CO and C2H4 sign gas and free radicals concentration is being to increase with the increasing of the temperature;coal being oxidized to product the amount of CO gas and C2H4 gas and the concentration of free redicals that have a periodic law：the regenerative stage of low-temperature oxidation,CO gas is a small amount or does not appear,and free radical concentration has a small change;the stage of the thermal oxidation is to appear from the CO gas to C2H4 gas,CO formation with the oxidation temperature increases slowly,the concentration of free radicals increases gradually;the stage of the depth of oxidation is to appear C2H4 gas to H2 gas,the formation of CO and C2H4 have a rapid increase with the increase of oxidation temperature,free radical concentration increasing with the increase of oxidation temperature becomes smaller.