三种双子季铵盐缓蚀剂对钢片在气田采出水中缓蚀行为的影响

Inhibition Behavior of Three Gemini Quaternary Ammonium Salts on Sheet Steel in Produced Water of Gas Exploitation

徐子洋 山金城 高 明 陈华兴 冯于恬 庞 铭 刘义刚

XU Ziyang SHAN Jincheng GAO Ming CHEN Huaxing FENG Yutian PANG Ming LIU Yigang

为获得缓蚀性能优良的双子咪唑啉季铵盐缓蚀剂，以3种不同的胺类化合物与环氧氯丙烷和硫脲为原料，合成了3种双子咪唑啉季铵盐缓蚀剂（甲硝唑双子季铵盐G1、不对称咪唑啉季铵盐G2和双咪唑啉季铵盐G3），采用化学浸泡失重法、电化学极化曲线及电化学阻抗谱（EIS）技术研究了3种缓蚀剂对X52钢在某气井采出水（矿化度34330 mg/L）介质中的缓蚀行为，考了缓蚀剂浓度对缓蚀效率的影响，分析了双子季铵盐缓蚀剂作用机理。结果表明，缓蚀剂G1和G2为非对称结构，缓蚀剂G3为对称结构。3种缓蚀剂均表现出优异的缓蚀性能。在76℃下，随着3种缓蚀剂浓度的增加，X52钢的腐蚀速率显著降低，缓蚀效率增加。3种缓蚀剂缓蚀能力从强到弱的顺序为G3>G2>G1。3种缓蚀剂在X52钢表面的吸附缓蚀作用均满足Langmuir等温吸附曲线，吸附作用为物理吸附和化学吸附协同作用的混合型吸附模式。3种双子季铵盐缓蚀剂均为阳极抑制为主的混合型缓蚀剂，其在X52钢表面的成膜作用对双电层的影响较大。由于3种缓蚀剂分子结构及对称性的差异，影响了吸附过程中X52钢表面的覆盖度，导致了三者成膜行为和缓蚀性能的不同。

In order to obtain gemini imidazoline quaternary ammonium salt corrosion inhibitor with good inhibition performance，three gemini imidazoline inhibitors of quaternary ammonium salts，including metronidazole G1，asymmetric imidazoline G2 and bis-imidazoline G3，were synthesized by using epichlorohydrin，thiourea and three different amines. Chemical soaking for weight loss，electrochemical polarization curves and electrochemical impedance spectroscopy （EIS） were applied to compare the inhibition behaviors of three inhibitors on X52 steel in produced water of a certain natural gas well with 34330 mg/L salinity. The effect of inhibitor concentration on the inhibition efficiency was studied，and the mechanism of gemini quaternary ammonium salt corrosion inhibitor was analyzed. The results showed that inhibitor G1 and G2 were asymmetrical，while inhibitor G3 were symmetrical. Three inhibitors exhibited excellent inhibition performance. The corrosion rate of X52 steel decreased significantly and the corrosion inhibition efficiency increased with increasing concentration of three inhibitors at 76℃ . Three inhibitors were arranged according to the corrosion ability in following order：G3>G2>G1. All the adsorption and inhibition of three inhibitors on the surface of sheet steel accorded the Langmuir adsorption isotherm. The adsorption mode obeyed mixed-type of synergized chemisorption and physisorption. The three gemini quaternary ammonium salt corrosion inhibitors were all mixed corrosion inhibitors with anodic inhibition as the main factor. The film forming effect on the surface of X52 steel had a great influence on the electric double layers. Due to the difference of molecular structure and symmetry of three corrosion inhibitors，the coverage of X52 steel surface during adsorption process was affected，resulting in the difference of film forming behavior and corrosion inhibition performance of three inhibitors.

10.19346/j.cnki.1000-4092.2019.03.016