窑尾余热锅炉受热面上水泥生料灰的黏结特性实验研究

Experimental study on cohesive characteristics of cement raw meal ash on SP boiler tubes

窑尾余热锅炉（SP锅炉）是水泥窑低温余热利用系统的重要设备,通常SP锅炉受热面会发生严重的积灰而影响正常运行。在固定床实验台上对SP锅炉受热面上水泥生料灰的黏结特性进行了实验研究,采用扫描电子显微镜（SEM）分析了灰样的微观形貌、采用X射线衍射仪（XRD）对灰样进行了晶相分析,采用X射线荧光光谱仪（XRF）分析了灰样的元素组成,探讨了水泥生料灰黏结性积灰的形成机理。结果表明：随着温度的升高,积灰的黏结性增强,水泥生料灰在400℃以下呈现松散性积灰,在400~600℃会产生较弱的黏结灰;在650~700℃会生成黏结性较强的积灰,在700℃以上时产生难以去除的黏结性积灰;熔化的碱金属盐具有黏结力,将灰黏结在固体壁面形成黏结灰;水泥生料灰在700℃会发生化学反应生成极少量的硅方解石（2CaSiO4·CaCO3）,增强了黏结灰的黏结强度。

The suspension preheater waste heat boiler（SP boiler）is one of the important facilities in low temperature waste heat utilization system of cement kiln.However,serious deposition often occurred on heating surfaces,which heavily affects the continuous running of the SP boiler.In this paper,the cohesive characteristics of cement raw ash in SP boiler heating surface were experimentally investigated on a fixed bed.The morphology of ash was analyzed by SEM,the composition of ash was detected by XRD and the ultimate analysis of ash was analyzed by XRF to elucidate the cohesive mechanisms of the cement raw meal ash.The experimental results show that the cement raw meal ash was loose below 400 ℃,and changed to the cohesive ash above 700 ℃ which is very difficult to remove.The cement raw meal ash was bonded to the solid wall due to the strong cohesive stress of melted alkali metal salts.A little quantity of silica calcite（2CaSiO4·CaCO3）,which can strengthen the cohesive stress of cement raw meal ash,was found to be generated at 700 ℃.