咪唑啉膦酰胺盐酸盐在油田水中的缓蚀性能研究

Study on Corrosion Inhibition Performance of Imidazoline Phosphonoamide Hydrochloride in Simulated Oilfield Water

采用静态挂片失重法和电化学方法，研究了合成的环烷基咪唑啉膦酰胺盐酸盐（NIPH）在模拟油田水中对A3钢的缓蚀作用，并探讨了其缓蚀机理。实验结果表明：（1）NIPH在矿化度31．2g／L的模拟油田水中对A3钢具有较好的缓蚀效果，其缓蚀效果受溶液pH值影响较大。在显酸性的模拟油田水中，NIPH的缓蚀率远高于原模拟油田水中的缓蚀率；当溶液pH为5左右时，NIPH的缓蚀效果最好，且此时水中基本无沉积物，在80℃、24h条件下，投加量为30mg／L时，缓蚀率可达到92．43％，A3钢腐蚀率仅为0．0249mm／a，远好于我国石油天然气行业标准对污水腐蚀率的要求。（2）NIPH缓蚀剂具有较宽的适用温度范围（30--95℃），50℃左右时缓蚀效果最好。温度较低时，NIPH缓蚀剂以物理吸附为主；温度较高时则以配位键化学吸附为主；80℃时吉布斯吸附自由能△G^0为38．2kJ／mol。按电化学机理，NIPH属于阴极型为主的缓蚀剂。图1表5参8。

The corrosion inhibition performance of a naphthenic imidazoline phosphonoamide hydrochloride （NIPH） on mild steel A3 in a simulated oilfield produced water of TSD = 31.2 g/L was studied by means of static weight loss and electrochemical methods and its inhibition mechanisms ware explored. It was indicated that： （1） NIPH is a good corrosion inhibitor on mild steel A3 in the simulated water but is rather susceptible to changes in pH value of the simulation water; the corrosion inhibition performance of NIPH is notably improved in the acidic simulation water and the best inhibition is observed at pH≈5, under such conditions a percentage inhi- bition of 92.43% and a corrosion rate of mild steel A3 of 0. 0266 mm/a, a value much lower than that specified in Trade Standard for injection waters, are measured and practically no precipitate is created in the simulation water at 80℃ in 24 hrs with NIPH introduced at dosage 30 mg/L. （2） NIPH can be used in a wide range of temperatures from 30℃ to 95℃ and appears to be most effective at 50℃. NIPH as corrosion inhibitor functions mainly by physical adsorption at lower temperatures and by chemical adsorption at higher temperatures. The Gibbs adsorption free energy AGO was calculated to be 38.2 kJ/mol at 80℃. NIPH belongs to cathode-based corrosion inhibitors as shown by electrochemical mechanisms.