Advanced Water Management Centre, The University of Queensland, St Lucia, Brisbane, QLD, 4072, Australia.
Materials Engineering, School of Mechanical and Mining Engineering, The University of Queensland, Brisbane, QLD, 4072, Australia.
Water Res. 2020 Oct 1;184:116122. doi: 10.1016/j.watres.2020.116122. Epub 2020 Jul 3.
To maintain the integrity of the internal surfaces of the pipelines in oil and gas industry, chemicals, including corrosion inhibitors and biocides, are commonly dosed to prevent corrosion. Imidazoline and its derivatives are widely used corrosion inhibitors for the protection of oil pipelines, which have been shown effective in reducing general corrosion. As an effective biocide, free nitrous acid (FNA) is suitable to inhibit microbially influenced corrosion, induced by for example sulfate-reducing bacteria. In this paper, we hypothesize that the continuous addition of imidazoline and intermittent dosing of FNA, when used in combination, would yield effective control of both general and pitting corrosions. As a typical imidazoline derivative, N-b-hydroxyethyl oleyl imidazoline (HEI-17) was applied in conjunction with intermittent dosing of FNA in the experimental system, with the results compared with two control systems, one receiving HEI-17 only, and one receiving no chemical dosing. The corrosion properties were monitored with open circuit potential, electrochemical impedance spectroscopy, linear polarization resistance, 3D optical profiling, and weight-loss measurement. Following a single dose of FNA, the general corrosion rates in the experimental reactor dropped up to 50% of that in the reactor receiving continuous HEI-17 dosing (0.27 ± 0.04 vs. 0.54 ± 0.08 mm/y), but gradually recovered to 93.4% of that in 2.5 months. After the FNA treatment, the pitting corrosion was decreased by 64.6% compared with continuous HEI-17 dosing reactor for a month from measuring the cumulative distribution of the pitting depth. HEI-17 treatment alone showed moderate pitting corrosion inhibition effect (approx. 27%), and the FNA treatment inhibited the formation of deep pits effectively. The combined application of HEI-17 and FNA has shown synergistic effects and high efficiency in mitigating MIC in the simulated water injection system. This treatment strategy has strong potential to be applied in the practical oilfield operations.
为了保持油气行业、化工行业中管道内部表面的完整性，通常会投加包括缓蚀剂和杀菌剂在内的化学物质来防止腐蚀。咪唑啉及其衍生物被广泛用于保护输油管道的腐蚀，已被证明可有效减少全面腐蚀。作为一种有效的杀菌剂，游离亚硝酸（FNA）适用于抑制由硫酸盐还原菌等引起的微生物影响腐蚀。在本文中，我们假设连续投加咪唑啉和间歇性投加 FNA 联合使用，将有效控制全面腐蚀和局部腐蚀。作为一种典型的咪唑啉衍生物，N-羟乙基油基咪唑啉（HEI-17）与 FNA 的间歇性投加联合应用于实验系统，并与两个对照系统进行了比较，一个只接受 HEI-17，另一个不接受化学投加。通过开路电位、电化学阻抗谱、线性极化电阻、3D 光学轮廓和重量损失测量来监测腐蚀性能。单次投加 FNA 后，实验反应器的全面腐蚀速率下降了 50%，达到连续投加 HEI-17 （0.27±0.04 vs. 0.54±0.08mm/y）的反应器的 50%，但在 2.5 个月后逐渐恢复到 93.4%。FNA 处理后，与连续投加 HEI-17 的反应器相比，一个月后局部腐蚀的累积深度分布测量值降低了 64.6%。单独投加 HEI-17 具有中等的局部腐蚀抑制效果（约 27%），而 FNA 处理有效地抑制了深蚀坑的形成。HEI-17 和 FNA 的联合应用在模拟注水系统中对减轻微生物影响腐蚀表现出协同作用和高效性。这种处理策略在实际油田作业中有很大的应用潜力。
