H2SO4/NH4HSO4作用下锅炉尾部受热面积灰成垢机理Scaling Mechanism of Fly Ash on Rear Heating Surfaces Under H2SO4/NH4HSO4
韩高岩,吕洪坤,谢娜,周培焱,李易炜,肖海平
HAN Gaoyan,LYU Hongkun,XIE Na,ZHOU Peiyan,LI Yiwei,XIAO Haiping
摘要(Abstract)：
锅炉尾部受热面上的高强度垢影响了设备安全性和经济性。为阐明积灰成垢机理，进行了H_2SO_4/NH_4HSO_4与积灰的成垢实验，对灰垢样品进行扫描电镜形貌分析和X射线衍射成分分析，采用热力学平衡计算确定胶凝类物质。结果表明，H_2SO_4/NH_4HSO_4作用下灰粒表面产生絮状和针状结晶，粘连胶结为大块团聚体后形成灰垢，NH_4HSO_4作用下团聚固结更加明显。实验和热力学平衡计算表明，H_2SO_4与积灰反应生成石膏类硫酸盐胶凝材料；NH_4HSO_4与飞灰反应生成石膏类胶凝物质以及大量（NH_4）_2SO_4，具有更强结垢倾向。在H_2SO_4/NH_4HSO_4作用下，积灰反应生成的硫酸盐胶凝物质将松散灰粒粘连固结，导致低温受热面垢的形成。
The high-intensity scale on the heating surface of a boiler holds up its security and economic efficiency.To clarify the scaling mechanism,scaling experiments where H_2SO_4/NH_4HSO_4 reacted with fly ash were carried out.Scanning electron microscope morphology analysis and X-ray diffraction composition analysis were used to analyze the ash-scale morphology and composition supplemented with thermodynamics equilibrium calculation for determining cementing minerals which lead to scaling. The results showed that the flocculent and needle-like crystals formed on the surface of ash particles mixed with H_2SO_4/NH_4HSO_4;ash particles adhered and cemented into large agglomerates to form ash-scale,and agglomeration was more remarkable mixed with NH_4HSO_4. The experiment and thermodynamic equilibrium calculation showed that the fly ash reacted with H_2SO_4 to generate gypsum-like gelatinous sulfate substances;NH_4HSO_4 reacted with fly ash to generate gypsum-like gelatinous substances and a large amount of(NH_4)_2 SO_4 that tend to scaling. Under H_2SO_4/NH_4HSO_4,the gelatinous sulfates generated from actions of deposited ash consolidated the incompact ash particles,leading to the accumulation of ash scale on heating surface.
关键词(KeyWords)：
飞灰;结垢;胶凝材料;H2SO4;NH4HSO4
fly ash;scaling;cementing material;H_2SO_4;NH_4HSO_4
基金项目(Foundation): 杭州意能电力技术有限公司科技项目（EPRD2020-08）
作者(Author):
韩高岩,吕洪坤,谢娜,周培焱,李易炜,肖海平
HAN Gaoyan,LYU Hongkun,XIE Na,ZHOU Peiyan,LI Yiwei,XIAO Haiping
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