李金芳,吕洪坤,谢娜,时浩,程齐勇,肖海平
LI Jinfang,LYU Hongkun,XIE Na,SHI Hao,CHENG Qiyong,XIAO Haiping

• 1:杭州意能电力技术有限公司
• 2:国网浙江省电力有限公司电力科学研究院
• 3:华北电力大学
• 4:中冶华天工程技术有限公司

摘要(Abstract)：

Na_2SO_4是加剧高碱煤结渣的重要中间物质,硫酸钠的铝硅酸化过程会生成SO_3。通过Na_2SO_4-飞灰和Na_2SO_4-Al_2O_3-SiO_2体系的高温矿物演变实验、高温SO_3生成实验,并辅以热力学平衡计算,探究了不同体系中硫酸钠的铝硅酸化过程SO_3生成机理。结果表明:硫酸钠通过高温铝硅酸化反应生成钠长石、钠霞石等低熔点含钠矿物,诱发低温共熔加剧结渣。同时,600～1 000℃铝硅酸化过程析出SO_2和O_2,固相表面的SO2和O2分压高,因此生成少量SO_3气体。Na_2SO_4-飞灰体系在高温下SO_3生成量约为Na_2SO_4-Al_2O_3-SiO_2体系的1.5～2倍。燃用高碱煤时锅炉水平烟道渣层中的Na_2SO_4铝硅酸化,增加了烟气中SO_3浓度。
Na_2SO_4 is an important intermediate substance that aggravates the slagging of high-alkali coal.SO_3 is released during the aluminosilicate reaction of sodium sulfate.To clarify the generation mechanism of SO_3 in the aluminosilicate process,experiments on high-temperature mineral evolution and SO_3 generation of the Na_2SO_4-fly ash and Na_2SO_4-Al_2O_3-SiO_2 system were conducted and supplemented by the thermodynamic equilibrium calculation.The results showed that sodium sulfate converted into low-melting Na-containing minerals such as albite and nepheline through high-temperature aluminosilicate reaction,which induced low-temperature eutectic and aggravates slagging.Simultaneously,SO_2 and O_2 were precipitated during the aluminosilicate reaction process at 600～1 000℃.Partial pressure of SO_2 and O_2 around the surface of solid phase was high,thus a small amount of SO_3 gas was generated.The amount of SO_3 produced in the Na_2SO_4-fly ash system at high temperature was about 1.5～2 times that of the Na_2SO_4-Al_2O_3-SiO_2 system.The aluminosilicate reaction process of Na_2SO_4 occurred in the slag layer in the horizontal flue of high-alkali coal-fired boilers,which increased the SO_3 concentration in the flue gas.

关键词(KeyWords)： 硫酸钠;飞灰;铝硅酸化;SO_3生成
Na_2SO_4;fly ash;aluminosilicate reaction;SO_3 generation

Abstract:

Keywords:

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): 李金芳,吕洪坤,谢娜,时浩,程齐勇,肖海平
LI Jinfang,LYU Hongkun,XIE Na,SHI Hao,CHENG Qiyong,XIAO Haiping

DOI: 10.19585/j.zjdl.202106014

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