地面管网含硫酸性腐蚀环境用缓蚀剂的性能与作用机制

Performance and Action Mechanism of Corrosion Inhibitors Used in Sulfuric Acid Corrosive Environment of Ground Pipe Network

李 薛 孙振华 周海刚 魏 旭 周兆院 刘晶姝

LI Xue SUN Zhenhua ZHOU Haigang WEI Xu ZHOU Zhaoyuan LIU Jingshu

为了改善地面管网含硫酸性高温环境的腐蚀问题，用微波法合成了一种N掺杂碳点缓蚀剂NCDs，采用电化学和失重法测试了NCDs在25、60、90 ℃下对N80 钢片在模拟溶液中的缓蚀作用。结果表明，在相同NCDs浓度下，随温度的升高，缓蚀效率降低。在25 ℃下，缓蚀剂NCDs质量浓度为150 mg/L 时的缓蚀效率达到最大，达94.16%；在 60 ℃下，NCDs 质量浓度为 200 mg/L 时的缓蚀效率最大，为 82.92%；在 90 ℃下，NCDs 质量浓度为150 mg/L 时缓蚀效率达到 69.59%。对腐蚀形貌分析发现 90 ℃时，钢片表面的腐蚀坑深度和数目最多。吸附等温曲线表明，NCDs 在 90 ℃时吸附平衡常数最大，但高温会使其局部腐蚀更严重。此外发现N掺杂碳点的吸附类型为物理与化学混合吸附。该碳点缓蚀剂可有效解决地面管道高温下的腐蚀，延长使用寿命。

An N-doped carbon dots corrosion inhibitor was synthesized by microwave method to improve the corrosion problem of ground pipe network under sulfur-containing acidic high-temperature environment. Its corrosion inhibition effect on N80 carbon steel in simulated solution at 25 ℃，60 ℃ and 90 ℃ was tested by electrochemical and weight loss methods. The results showed that the efficiency of corrosion inhibitor（ECI）increased with the increase of the temperature. The ECI reached the maximum of 94.16% at the temperature of 25 ℃ at the NCDs dosage of 150 mg/L. The maximum was 82.92% at the temperature of 60 ℃ at the NCDs dosage of 200 mg/L. At the temperature of 90 ℃ and at the NCDs dosage of 150 mg/L，it reached up to 69.59%. The analysis of corrosion morphology showed that the depth and number of corrosion pits on the steel were the largest at the temperature of 90 ℃. The adsorption isotherm curve showed that the adsorption equilibrium constant of NCDs was the largest at 90 ℃，but the local corrosion was more serious at high temperature. In addition，it is found that the adsorption type of N-doped carbon dots was physical and chemical mixed adsorption. The carbon dots corrosion inhibitor could effectively solve the corrosion of ground pipelines at high temperature and prolong the service life.

10.19346/j.cnki.1000-4092.2023.03.020