地热水管道不锈钢管材腐蚀与结垢试验

Experiment of stainless steel corrosion and scaling in geothermal water supply pipeline

在模拟流动地热水环境装置中,分析了不锈钢管材在50℃条件下的表面腐蚀与结垢行为,探讨了不锈钢表面腐蚀与沉积结垢对地热水中离子浓度、自腐蚀电位和质量的影响.研究表明,不锈钢管表面有呈针状堆积的结垢物(主要为CaCO3),而且发生了点腐蚀,腐蚀坑密度随流动地热水作用时间的延长而增加.由于不锈钢表面的点腐蚀、沉积结垢物及流动模拟地热水的冲刷导致的结垢层脱落等过程的影响,模拟地热水溶液中的Ca2+,Mg2+浓度明显下降,至600 h后基本稳定;不锈钢材料的自腐蚀电位在试验前350 h上升,而后稳定在约0.044 V;其质量由于流动模拟地热水的作用表现出不断增加的趋势.

The corrosion and scaling on the surface of the 304 stainless steel（SS） pipe in the flowing geothermalwater at 50 ℃ were studied using the circulating-water environment simulator.The effects of corrosion and scaling on mass concentration of ions in geothermal water,corrosion potential and mass of the SS pipe were discussed.The results show that the needlelike scales were accumulated on the surface of the sample.The pitting corrosion also occurs.With time increasing,the density of corrosion pits increases.Due to the corrosion,scaling and descaling on the surface,the concentrations of Ca2＋and Mg2＋decline significantly in the first 600 h,after that they keep constant.The corrosion potential of the SS pipe increases in the first 350 h,then it is stable at 0.044 V.The quality keeps increasing during the whole soaking process.