Effects Of Combustion-supporting Additives On Combustion Characteristic Of Inferior Coals In Cement Industry And Its Mechanism

With the reduction of high quality coal and the rising of coal price increasingly, theutilization of low quality coals has become a trend at present, combustion supporting additivesare considered to be effective and clean way to use inferior coals. therefore, it is significant todevelop combustion supporting additives of cement industries.In this paper, seven kinds of typical inferior coals of cement industries were used as fuel,and the catalytic combustion experiments were carried out. The conflagration method, thermalanalysis, dynamic analysis, X ray diffraction analysis and scanning electron microscopy analysiswere used as the study methods. Burnout degree, volatile releasing characteristic, ignitiontemperature, burnout temperature and burnout index were applied to determine the catalyticeffects.The results indicated that coals type, additives, additives mixing way and its amounts hadsignificant influences on the catalytic combustion. Burnout degree was enhanced with theincreasing of volatile matters. 0.5% was proved to be as the optimal amount of the additives. Inaddition, the influence of additive mixing way on coal combustion was the following: soaking >spraying > dry mixing. The coal with 0.5% CSA 01, CSA 02, BaCO3and ZnO were comparedunder same combustion condition to investigate the impact of additive type. The ignitiontemperature and burnout temperature of catalytic samples were all decreased. Meanwhile, theburnout indexes of catalytic samples were enhanced except CSA 01. Kinetic parameters of thecoal combustion with or without additives were calculated. The apparent activation energies (E)of the coal combustion were reduced with additives. Moreover, The most probable mechanismfunction of the coal combustion was f(α)=(1α)~2. The additives could reduce the activationenergy of coal combustion, thus they could reduce the ignition temperature and improvecombustion rate. At the same time, it could reduce the carbon content of the fly ash. The studyprovided a theoretical basis for the industrial application of additives in cement industries.