生物质混煤燃烧过程中硫氯协同腐蚀特性研究

Study on Sulfur-Chlorine Synergistic Corrosion in Biomass and Coal Co-Firing

采用管式炉试验系统模拟生物质混煤燃烧炉膛环境,通过静态增重试验研究腐蚀性气氛和受热面温度变化时的硫氯协同腐蚀特性,并结合X射线图谱分析(XRD)和差热分析(DTA)进一步讨论硫氯腐蚀机理,从而为锅炉安全运行和生物质燃料的有效利用提供理论依据。结果表明,各工况下硫氯协同腐蚀均符合抛物线规律,即前期存在一个快速腐蚀阶段,随后腐蚀趋势逐渐变缓;硫氯气氛下SO2明显表现出对HCl腐蚀的抑制作用,HCl浓度变化对硫氯腐蚀的影响较小;温度对协同腐蚀的影响符合Arrhenius定律;积灰存在时腐蚀程度增强,此时SO2浓度升高会在一定程度上加剧腐蚀,主要是由于积灰中的硫酸盐化作用及熔融液相腐蚀引起,HCl能够通过增强积灰中的液相腐蚀作用而加剧腐蚀。

A tube furnace system was employed to simulate biomass and coal co-firing processes, and sulfur-chlorine synergistic corrosion was investigated through a static corrosion weight gain method by changing composition and temperature. X ray diffraction（XRD） and different thermal analysis（DTA） were employed to study the reaction mechanism to provide theoretical supports for safe operation of boilers and effective use of biomass. The results indicate that the synergistic corrosion process shows a parabolic profile： the corrosion rate increases initially, and then gradually decreases. Meanwhile, SO2 can significantly inhibit HCl corrosion and the change of HCl concentration has few effects on synergistic corrosion. Furthermore, the effect of temperature on synergistic corrosion follows Arrhenius law. Corrosion is strengthened with the existence of deposition, and the increment of SO2 concentration might enhance the corrosion, which is due to the effect of sulfationin deposition and molten liquid corrosion, and HCl can also intensify the corrosion with the increment of molten liquid corrosion.