Abstract:

To investigate the effect of electrochemistry on scaling and corrosion of carbon steel materials in circulating cooling water systems, an electrochemical treatment system with a Ti/RuO₂ anode and a Ti mesh cathode as the core was constructed, and coupled with a rotating corrosion rate meter and a circulating cooling water dynamic simulation system, respectively. The parameters of the electrochemical system were first optimized by the descaling effect and current efficiency. The experimental results showed that 15V and 120min treatment time were the optimum electrochemical treatment parameters. The results with electrochemical coupling rotary corrosion rate meter indicated that electrochemical embedding can reduce the rate of carbon steel surface scale deposition for different hardness of water. XRD and SEM analyses found that the calcite-dominated to aragonite-dominated crystalline form of scale on the surface of carbon steel was transformed. However, electrochemical embedding in low-hardness solutions can significantly increase the corrosion rate of carbon steel, while in hard water with high hard water quality the surface of carbon steel can form a uniform and dense layer of Fe₃O₄. The corrosion rate of carbon steel was reduced from 0.60mm/a and 0.54mm/a to 0.47mm/a and 0.32mm/a, respectively. The results of the electrochemical coupled circulating cooling water dynamic simulation device showed that the fouling thermal resistance of the circulating cooling water simulation system was significantly reduced after embedding the electrochemical module. After data analysis, when the water quality was low hardness water, the carbon steel corrosion rate increased after embedding the electrochemical system, while when the water quality was high hardness water, the corrosion rate was reduced from 0.12mm/a, 0.15mm/a to 0.10mm/a, 0.13 mm/a, respectively. It was shown that electrochemical embedding can significantly reduce the rate of scale deposition in the system, but pose the risk of increased corrosion when the water hardness was low, providing a reference for the safe promotion of subsequent electrochemical technology.

Key words: electrochemical, circulating cooling water, scale deposition, corrosion, Fe₃O₄ layer

摘要：

为探究电化学对循环冷却水系统碳钢材料结垢和腐蚀的影响，构建了以Ti/RuO₂阳极和Ti网阴极为核心的电化学处理系统，将其分别与旋转腐蚀速率仪和循环冷却水动态模拟系统进行联用。首先通过除垢效果和电流效率对电化学系统进行参数优化，实验结果显示，15V电压、120min处理时间为最优电化学处理参数。电化学联用旋转腐蚀速率仪实验结果显示，对于不同硬度的水质，电化学嵌入后均可降低碳钢表面垢沉积速率。XRD和SEM分析表明，碳钢表面水垢晶型以方解石为主转化为以文石为主。但当水质为软水时，电化学嵌入可明显加剧碳钢腐蚀速率；而当电化学嵌入硬水与高硬水水质时，挂片表面可形成均匀、致密的Fe₃O₄层，碳钢腐蚀速率由0.60mm/a、0.54mm/a分别降至0.47mm/a、0.32mm/a。电化学联用循环冷却水动态模拟装置实验结果显示，嵌入电化学模块后，循环冷却水模拟系统的污垢热阻均显著降低。经数据分析，当水质为软水时，嵌入电化学系统后碳钢腐蚀速率增大，而当水质为高硬水时，碳钢腐蚀速率分别由0.12mm/a、0.15mm/a降至0.10mm/a、0.13mm/a。表明电化学嵌入可显著降低系统水垢沉积速率，但水质硬度较低时，会带来腐蚀加剧风险。本研究为后续电化学技术的安全推广提供了参考依据。

关键词: 电化学, 循环冷却水, 垢沉积, 腐蚀, Fe₃O₄层