农业生物质稻草与烟煤混烧特性及动力学分析

摘要

In order to take full use of the agricultural biomass straw and bituminous coal,the thermogravim-etric-differential thermogravimetric-differential scanning calorimetry (TG-DTG-DSC ) thermal analysis technology was employed to conduct thermogravimetric experiment on straw,bituminous coal and their mixtures.The combustible characteristics,ignition performance,burnout feature and comprehensive com-bustion characteristics of the fuels were investigated.Moreover,the combustion mechanism of the mixed fuel was analyzed,and kinetics parameters of the combustion were calculated.The results show that,DTG curves of the mixture of straw and bituminous coal appeared two peaks.With an increase in the proportion of straw in the mixture,an upward endothermic peak gradually appeared on the DSC curve,between the two peaks on the DTG curves.The ignition temperature of the mixed sample was much lower than that of the bituminous coal.The mixture S6 had the lowest ignition temperature and burnout temperature.Its maximum and average reaction speed was higher than that of other mixtures.The combustible characteris-tics index,ignition performance index,burnout feature index and comprehensive combustion characteristics index of S6 were much higher than that of other mixed fuels and the bituminous coal.Furthermore,these indexes of S6 increased with the proportion of straw.The early burning stage of the mixed fuels was mainly homogeneous ignition,while the late stage was multiphase ignition.The reaction order of the mixed fuels at low/high temperature was about 1.5/0.4.The reaction activation energy and frequency factor at low tem-perature were larger than that at high temperature,reflecting consistency of variation of the activation en-ergy and frequency factor.Properly adding biomass straw was beneficial to promoting full combustion of the bituminous coal,which will improve the combustion efficiency and reduce the net environmental pollu-tion.%采用TG-DTG-DSC联用技术对农业生物质稻草、烟煤及其混合燃料进行了热重实验,研究了其可燃特性、着火特性、燃尽特性及综合燃烧特性,分析了混合燃料的燃烧机理,并计算了燃烧动力学参数.结果表明：稻草与烟煤混烧的DTG曲线出现2个峰值,随着稻草在混合燃料中所占比例的增加,在DTG曲线2个峰值之间,DSC曲线逐渐出现向上的吸热峰；混合试样的着火温度大大低于烟煤的着火温度,混合燃料 S6(稻草∶烟煤＝4∶1)的着火温度及燃尽温度最低,其最大反应速度和平均反应速度均大于其他混合燃料的值；混合燃料的前期主要属于均相着火,后期属于多相着火；混合燃料在低温阶段反应级数约为1．5,高温阶段反应级数约为0．4；混合燃料低温阶段活化能及频率因子均大于高温阶段的活化能及频率因子,体现了活化能与频率因子变化的一致性；在烟煤中适当加入生物质稻草有利于促进烟煤的充分燃烧,提高其燃烧效率,从而降低纯烧煤所带来的环境污染.