燃机电站余热锅炉硫酸露点腐蚀试验研究

Experimental Study on Sulfuric Acid Dew Point Corrosion of Waste Heat Boiler in Gas Turbine Power Station

硫酸露点腐蚀可导致燃机电站余热锅炉安全性与经济性降低。为探究其机理,结合现场运行工况,按热力学原理计算出了燃机电站余热锅炉凝结硫酸浓度分布值。以此为依据,对余热锅炉常用的20 G钢进行了硫酸露点腐蚀模拟试验;结合电化学工作站、透反射金相显微镜、扫描电子显微镜(SEM)、X射线衍射(XRD),对20 G钢的电化学性能及表面形貌进行了分析。试验结果表明:低温-低浓度硫酸腐蚀情况比高温-高浓度硫酸腐蚀情况严重,若将给水加热器入口水温提高至80℃以上,可减小低温段管道腐蚀速率。

The safety and economy of the waste heat boiler of the gas turbine power station will be undermined because of the sulfuric acid dew point corrosion.To figure out the exact mechanism,by taking account of the field operating conditions,the distribution value of the condensation acid concentration of the waste heat boiler of the gas turbine power station is calculated according to the thermodynamic principle.Based on this,the dew point corrosion simulation experiments of 20G steel used for the waste heat boiler is carried out.The electrochemical performance and surface morphology of 20G were analyzed by electrochemical workstation,transflective metallographic microscope,scanning electron microscope(SEM)and X-ray diffraction(XRD).The results of immersion test show that the low temperature-low concentration sulfuric acid corrosion is much more destructive than the high temperature-high concentration sulfuric acid.If the inlet water temperature of the feedwater heater is raised to above 80°C,the corrosion rate of the pipeline can be greatly reduced in its low temperature section.