Study On Kinetic Characteristics Of CO And CO₂Productions From The Low-temperature Oxidation Of Coal

Low-temperature oxidation of coal spontaneous combustion of coalself-heating leading to seriously affect the development of the coal industry,resulting in waste of resources, casualties and property losses. Using the basictheory of low-temperature oxidation of coal, low-temperature oxidation of coalduring the CO, CO2generation dynamics, analyzing the apparent activationenergy of CO and CO2, by the apparent activation energy of these two gases toreveal the mechanism of low-temperature oxidation of coal, which methods forforecasting coal spontaneous combustion prediction to provide technicalservices, and can guide the spontaneous combustion of coal mine fire preventionwork site.This paper selects four different metamorphic grade XiMeng lignite (XM),God East sub-bituminous coal (SD), bituminous coal Zaozhuang (ZZ) and Yimagas coal (YM) for the study, low-temperature oxidation kinetics of coal CO, CO2generated by the reaction kinetics theory, different size, different quality,different reaction times and different rank coals gas products dynamics at lowtemperature oxidation process, the following conclusions:(1) Low-temperature oxidation of coal consumed O2law: the smaller theparticle size of coal samples, the greater the contact area of coal and oxygenmolecules, the probability of a large coal combines with oxygen, oxygenconsumption is large. When the oxygen concentration is reduced to a certain extent, the oxygen molecule is more difficult to spread to the coal inside thebody, so the low oxygen in a closed environment, coal is not with the reductionof oxygen consumption of coal particle size showed an increasing trend. Fordifferent coals, the existence of differences in the internal structure of coal andcoal varying degrees of difficulty with oxygen molecules, lead to the existenceof differences in their own oxidation.The higher the rank, the less O2consumption.(2) Coal low temperature oxidation of CO and CO2generated during law;temperature, CO and CO2generated were tested decreasing trend apparentactivation energy and the apparent activation energy is greater than the CO2generated CO apparent activation energy is generated, indicating that the lowtemperature oxidation of coal tends to produce more CO2.(3) Experimental studies have shown CO apparent activation energy andcoal-related generation. This paper selects XM coal, SD coal, ZZ YM coal andcoal rank higher and higher, CO to generate the apparent activation energyincreases with the degree of deterioration becomes larger, the oxidationtemperature is different, different ways CO release. However, regardless of theapparent activation energy of CO2generated coal. Four coals at different stagesof CO2generated little difference between the apparent activation energy, whichshows four coal complex transition much the same kind of decomposition ofCO2.(4) According to the low temperature oxidation of coal in the apparentactivation energy of CO and CO2with temperature variation, the concept oflow-temperature oxidation of coal activation mechanism, namely: coal lowtemperature oxidation process is a continuous oxidation rely on heat productionand activation of reactive functional groups react with oxygen to release heat thecoal itself and increase heat buildup, resulting in continuous coal oxygenreaction phenomena and processes. And with this mechanism may explain thelow-temperature oxidation of coal in the apparent activation energy decreases with increasing temperature and different reasons for different coal spontaneouscombustion tendency.