Study On Low-temperature Oxidation Characteristics And Influencing Factors Of Highly Active Pulverized Coal

With the high efficiency energy saving and low pollutant emission, the pulverized coal industrial boiler system has been rapidly extend, and great economic benefits and social effect has been obtained. High volatilization pulverized coalwith diameter less than 75 μm is used as main fuel of the pulverized coal industrial boiler. This highly active pulverized coal is easy to be oxygenized in the air, and spontaneous combustion accident might occurwhen in the adverse heat exchange condition, which threatens the safety of pulverized coal industrial boiler operation. The internal property of pulverized coal spontaneous combustion is its low temperature oxidation characteristics. So it is important to study the low temperature oxidation characteristic of pulverized coal with high activity.In order to investigate the low-temperature oxidation of highly active pulverized coal and its influencing factors, Bulianta long-flame coal was selected as the main research object, Yuanbaoshan lignite and Liulin coking-coal were selected as compared objects to Bulianta long-flame coal in this paper. The variation of chemical and physical interface structures with temperature,the macro-characteristics during the process of spontaneous combustion, and the influence of volatile, heating rate, oxygen concentration, particle size, andmoisture on ow-temperature oxidation characteristics of Bulianta long-flame coal were mainly studied.By scanning electron microscope, it is found that:with temperature rising, the surface of the pulverized coal becomes coarse, the amount of pores increases. By nitrogen adsorption experiment, the rule between pore volume, specific surface area and temperature was obtained. By the method of in situ diffuse reflectance FTIR, the spectral characteristics of pulverized coal in different temperature were studied. The variation law of the main functional groups with different chemical reactions during low-temperature oxidation process was obtained. By adiabatic oxidation experiment, the pulverized coal spontaneous combustion process was simulatedand produce gas during the experiment was measured by gas chromatography. By analyzing the TG, DTG and DSC curves, the influence of volatile, heating rate, oxygen concentration, particle size and moisture content to low temperature oxidation was studied.The work of this paper is helpful to the understanding the low-temperature oxidation of highly active pulverized coal and the effect law of its influencing factors, andthe work might supply a guidance to improve the safety of pulverized coal industrial boiler operation.