准东混煤高碳飞灰物相热转化差示扫描量热分析  

DSC analysis for phase thermal transformation of high-carbon fly ash of Zhundong blended coal

作　　者：田思达[1] 李乐天 康志忠[1] 王迪 TIAN Sida;LI Letian;KANG Zhizhong;WANG Di(Key Laboratory of Condition Monitoring and Control for Power Plant Equipment,Ministry of Education,North China Electric Power University,Beijing 102206,China)

机构地区：[1]华北电力大学电站设备状态监测与控制教育部重点实验室

出　　处：《热力发电》2019年第12期46-51,共6页Thermal Power Generation

基　　金：国家自然科学基金项目(51376061);国家科技支撑计划项目(2015BAA04B02)~~

摘　　要：为了深入认识准东混煤高碳飞灰的灰沉积特征,使用差示扫描量热法(DSC)和X射线衍射法(XRD)对一种准东混煤高碳飞灰和2种其他飞灰的物相热转化特征进行对比研究。结果表明:准东混煤飞灰的残留碳经500℃热处理基本燃尽,对其高温加热的物相转化没有明显影响;DSC测试低温阶段,3种灰熔点不同的飞灰的放热流量变化趋势相近,而在880℃以上准东混煤飞灰DSC放热热流量随着温度升高增加得越来越快,并在1080℃达到峰值。这是由于飞灰中的氧化钙、硫酸钙等含钙物质和含钠物质与铝硅酸盐物质结合生成大量含钠钙长石,钙黄长石和硅酸钙是其中间产物。这种混煤飞灰在锅炉内烟气温度不低于1 080℃的区域沉积会自我固化造成沾污或结渣。In order to further understand the deposition characteristics of high-carbon fly ash of Zhundong blended coal,differential scanning calorimeter(DSC)and X-ray diffractometer(XRD)were used to study the phase thermal transfonnation characteristics of one high-carbon fly ash of Zhundong blended coal and two other fly ashes.The results show that,the residual carbon in the Zhundong blended-coal fly ash burned out basically after a heat treatment at 500℃,it had little effect on the phase thermal transformation of fly ash at higher temperatures?In the low-temperature stage ofDSC measurement,the heat release fluxes of the three fly ashes with different ash melting points had similar change trend.At temperatures above 880℃,the DSC heat release flux of the Zhundong blendedcoal fly ash increased more and more rapidly with the temperature,and reached its peak value at 1080℃.This is due to the combination of calcium-containing and sodium-containing substances in fly ash with aluminosilicate substances to produce a large amount of sodium-containing anorthite,in which gehlenite and calcium silicate are the intermediate products.When depositing on the boiler heating surface where the flue gas temperature was not lower than 1080℃,this kind of fly ash can solidify itself and cause fouling or slagging.

关 键 词：准东煤 结渣沾污 混煤燃烧 高碳飞灰 差示扫描量热法 钙长石 热转化 

分 类 号：TK16[动力工程及工程热物理—热能工程]