滨二污水站处理系统腐蚀成因分析及对策研究

Corrosion Analysis and Control Measures in the 2nd Binnan Water-Treating Plant

滨南采油厂滨二污水站处理后回注污水腐蚀性很强。极化曲线显示,未处理污水含多种阴极去极化剂,腐蚀过程由阴极反应过程控制,点蚀倾向大,实验考察和无机垢分析明确了游离CO2和SRB菌在腐蚀中的重要作用。据此筛选了新开发的杀菌缓蚀剂2号,该剂为改性咪唑啉衍生物,加有有杀菌作用的小分子胺,为混合控制型成膜缓蚀剂。提出了滨二污水处理站缓蚀技术并在现场实施：以1.0 g/L的量连续72小时注入溶垢剂;以20 mg/L的量连续8小时注入污泥剥离剂;以200 mg/L的量连续6-8小时注入杀菌缓蚀剂2号完成预膜;分别在来水进口和过滤器前加杀菌缓蚀剂2号,初始总加量240 mg/L,在混合反应器进口和中部加两种絮凝剂共110 mg/L,2个月后杀菌缓蚀剂2号加量已逐步减至40 mg/L,处理后污水腐蚀速率保持在0.07 mm/a以下。

The purified recycled produced water（RPW） of the 2nd Binnan water-treating plant was highly corrosive.The polarization curves indicated that in the RPW,containing various cationic depolarizing agents,the corrosion was controlled by the cationic processes and there existed a notable tendency to pitch corrosion;free CO2 and SRB bacteria were important corrosion factors as shown by experimental results and scale analysis.A newly developed bactericide/corrosion inhibitor #2（B/CI-2） is chosen.It was composed of a modified imidazoline derivative with a bactericidal amine added,being a filming agent of cationic/anionic mixed control.A corrosion inhibition technology was suggested and applied in the 2nd Binnan water-treating plant;to inject the water-treating system with a scale dissolving agent at a dosage of 1.0 g/L in 72 hrs and then with a sludge remover at a dosage of 20 mg/L in 8 hrs;introduce into the system B/CI-2 at a dosage of 200 mg/L in 6～8 hrs to perform the prefilming process;introduce B/IC-2 at an initial dosage of 240 mg/L in the inlet and before the filter and flocculants A and B at a total dosage of 110 mg/L in the mixer/reactor;2 months after the dosage of B/CI-2 was reduced steprise to 40 mg/L and corrosion rate of the treated RPW was kept at a level of 〈0.07 mm/a.