变压器油中新型环境友好金属钝化剂表面钝化特性及机理研究

The corrosive sulfur (mainly DBDS) in mineral insulating oil can react with copper at high temperature to afford semi-conductive copper(I) sulfide, which contaminates oil-paper insulation and causes insulation breakdown at last. This problem has high impact on the safe operation of transformers. Adding traditional benzotriazole derivatives as metal passivators into transformer oil is thought to be important prevention measures. The key point for the protection caused by metal passivator is to form a stable passivation film to prevent corrosion. However, traditional metal passivators suffer from high toxicity and serious environment problem. This project will focus on new-type environment-friendly metal passivator. We will utilize benzimidazole as skeleton to synthesize new-type metal passivator and synthesize specific electron- and stereo-demanding small molecule probe to investigate the mechanism of passivation film formed on the surface of copper. We will study passivation film property on copper surface with new-type passivator under different corrosive level and build up model for predicting the corrosive level caused by DBDS. Furthermore, we will study the depletion property and build up mathematical model of new-type metal passivator under various temperatures, various concentration of anti-oxidant and various unit areas of copper. This project can provide theoretical fundamentals and experiment results for the development of copper surface protection methods.

变压器用矿物绝缘油中的腐蚀性硫DBDS在高温下与铜相互作用形成半导电的硫化亚铜，渗入到油纸绝缘系统中造成变压器绝缘性能下降，极大地影响电力变压器的运行安全。往变压器油中添加传统的苯并三氮唑类金属钝化剂，可在铜片表面形成稳定钝化膜有效抑制腐蚀性硫的腐蚀，然而其存在高毒性和对环境危害大的弊端。本项目围绕新型环境友好的钝化剂进行研究，以苯并咪唑为骨架设计合成新型金属钝化剂；制备出具有不同电子和立体效应的小分子探针，探究钝化剂在铜表面成膜的机理；研究新型钝化剂与传统钝化剂对已腐蚀铜片表面的钝化特性差异与变化规律，建立体系腐蚀半定量表征方法及钝化剂有效性评价模型；研究新型钝化剂在温度、抗氧化剂和铜片面积等单因素作用下的消耗规律，建立单因素作用下新型金属钝化剂消耗的数学模型。为变压器绕组铜表面防护方法和技术提供新的理论基础和实验依据。

变压器油中的腐蚀性硫DBDS在高温下与铜相互作用形成半导电的硫化亚铜，该物质渗入到油纸绝缘系统中造成变压器绝缘的破坏，极大的危害变压器的运行安全。通常通过添加苯并三氮唑类金属钝化剂形成钝化膜来有效抑制腐蚀，然而苯并三氮唑钝化剂毒性较大，对环境不友好。本项目围绕新型环境友好的钝化剂进行研究，利用小分子探针和表面分析技术研究钝化剂在绕组导体铜表面的成膜机理，发现杂环1，2位的位阻效应影响成膜的有效性，据此设计并合成苯并咪唑类衍生物为新型金属钝化剂，该类型钝化剂效果明显，且热稳定性高；利用加速热老化实验、表面分析技术和绝缘纸理化性能检测技术系统地研究了金属钝化剂的有效性、安全性，实验表明金属钝化剂能有效延缓已腐蚀铜片的腐蚀速率，金属钝化剂在成膜后，其钝化膜会在热场下逐渐分解，需要足够浓度的金属钝化剂维持钝化效果，多次添加金属钝化剂不会对油质和纸绝缘产生影响；建立高效液相色谱检测钝化剂含量的方法，并研究了不同状态的绝缘油、铜片、绝缘纸、温度、氧气和抗氧化剂对钝化剂含量的影响，建立金属钝化剂的消耗动力学方程；研究了腐蚀性硫二苄基二硫醚绝缘油的再生处理技术，利用氧化剂+分子筛偶联体系，实现腐蚀性硫二苄基二硫醚的高效脱除，吸附剂用量少，处理时间短。本项目的研究成果为变压器绕组铜表面防护理论和方法提供新的理论基础和实验依据。