高浓缩倍率冷却水中304不锈钢耐蚀性能研究

Anti-Corrosion Performance of 304 Stainless Steel in High Concentrated Cooling Water

高浓缩冷却水中离子浓度的提高对冷却管的耐蚀性能会产生影响。采用某电厂循环水补充水,研究了304不锈钢在不同浓缩倍率的冷却水、经某低磷药剂处理的冷却水,以及含低磷药剂并加酸处理的冷却水中的耐蚀性能。结果显示:在未经处理的冷却水中,随着浓缩倍率的提高,不锈钢的过钝化电位或点蚀电位下降,点蚀敏感性增大;冷却水中加入低磷药剂时,不锈钢耐蚀性能随着药剂浓度的增加而提高;当含低磷药剂的冷却水经进一步加酸处理时,不锈钢的耐蚀性能也得到进一步的增强。通过不同处理引起的冷却水pH值及阴离子浓度变化,讨论了加阻垢剂和加酸处理提高冷却水中黄铜耐蚀性能的原因。

The increase in ion concentration in the high-concentrated cooling water can affect the corrosion resistance of the cooling pipe.Using the supplemental water for the circulating cooling water system in a power plant,the corrosion resistance of 304 stainless steel in the cooling water with different concentration ratios,the cooling water treated with a low-phosphorus scale inhibitor,and the cooling water treated together with a low-phosphorus inhibitor and acid are investigated.The results exhibited that the over-passivation potential or pitting potential of stainless steel decreased in untreated cooling water as the concentration ratio increased,and the pitting sensitivity increased.When the low-phosphorus scale inhibitor was added to the cooling water,the corrosion resistance of the stainless steel increased with the concentration of the scale inhibitor.When the cooling water containing the scale inhibitor was further acid-treated,the corrosion resistance of the stainless steel was further improved.According to the change of pH value and anion concentration of cooling water caused by different treatments,the reasons for corrosion resistance improvement of brass by adding corrosion inhibitor and acid treatment in cooling water were discussed.