摘要
为探讨生物质锅炉受热面飞灰沉积腐蚀特性,通过腐蚀增重研究生物质灰对锅炉受热面常用12Cr1MoV钢材高温腐蚀的影响,并结合X射线图谱(X-Ray Diffraction, XRD)分析和扫描电镜-能谱(Scanning Electron Microscopy-Energy Dispersive Spectrometer, SEM-EDS)分析系统研究了金属表面有无积灰、积灰中KCl无机盐的质量浓度、生物质水洗预处理等因素对锅炉受热面金属腐蚀的影响及作用机制。研究结果表明,对于任一腐蚀工况条件下,金属的腐蚀增重曲线均随着腐蚀时间的变化呈现半抛物线趋势:即腐蚀增重先迅速增加,而后趋于平缓;生物质灰中高质量浓度的KCl无机盐有助于促进低温共熔物的增多,进而加速腐蚀;试验温度600~700℃条件下,12Cr1MoV钢材表面发生Ⅱ型热腐蚀,热腐蚀初期KCl以固态形式存在,腐蚀速率较低,当Cr_(2)O_(3)氧化膜失去保护作用后,KCl-K_(2)CrO_(4)和KCl-FeCl_(2)低温共熔物增大腐蚀速率;KCl质量浓度越高,反应初期腐蚀更均匀,反应速率越小,但腐蚀后期速率更快;水洗预处理制成的灰通过降低KCl的质量浓度,可以有效减轻积灰对金属腐蚀的影响;在600℃无水蒸气条件下,水洗预处理腐蚀速率能够下降17%。
A high-temperature corrosion test system for biomass ash was established using an atmosphere-controllable tube furnace.The corrosion material used was 12Cr1MoV steel,which is typical in biomass boilers.The study examined the influence of corn stalk ash on the high-temperature corrosion of 12Cr1MoV steel by measuring the weight gain due to corrosion.Additionally,the effects of ash accumulation on the metal surface,the mass concentration of KCl inorganic salts in the ash,and the impact of biomass water washing pretreatment on metal corrosion of the boiler heating surface were investigated using X-Ray Diffraction(XRD)and Scanning Electron Microscopy with Energy Dispersive Spectroscopy(SEM EDS).The results indicate that the corrosion weight change curves of the test steel follow a semi-parabolic trend over time:initially increasing rapidly before leveling off.Fly ash deposition accelerates corrosion on the heating surface.At 700℃with water vapor present,the corrosion reaction rate of the coated sample is 1.367 times that of the uncoated sample.KCl,an inorganic salt with high mass concentration in biomass ash,promotes the formation of low-temperature eutectics and accelerates corrosion.At test temperatures of 600700℃,typeⅡhot corrosion occurs on the surface of 12Cr1MoV steel.Initially,KCl exists in solid form,resulting in a low corrosion reaction rate.However,as the test progresses,the protective Cr_(2)O_(3) oxide film deteriorates,and the formation of KCl K_(2)CrO_(4) and KCl FeCl_(2) low-temperature eutectic products accelerates the corrosion reaction rate.Higher KCl content leads to more uniform corrosion in the initial stage and a lower corrosion reaction rate,but results in a faster reaction rate in the later stage.Ash produced by water washing pretreatment effectively reduces the impact of ash accumulation on metal corrosion by lowering KCl content.At 600℃without water vapor,the corrosion reduction rate achieved through water washing pretreatment can reach 17%.At 700℃without water vapor,the corrosion mitigation effect of water washing pretreatment decreases to approximately 4.7%.However,in the presence of water vapor at the same temperature,the mitigation effect improves,reducing the corrosion reaction rate by about 6.2%.These results indicate that water vapor enhances the corrosion resistance provided by water washing pretreatment.
作者
姚锡文
许克强
杨婉婷
许开立
YAO Xiwen;XU Keqiang;YANG Wanting;XU Kaili(College of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China)
出处
《安全与环境学报》
北大核心
2025年第6期2189-2197,共9页
Journal of Safety and Environment
基金
国家自然科学基金项目(52474214)。
关键词
安全工程
生物质
钢材
KCL
灰沉积
高温腐蚀
safety engineering
biomass
steel
KCl
ash deposition
high temperature corrosion
