油田化学添加剂对污水处理系统腐蚀行为的影响

目的明确净水剂、絮凝剂、助凝剂、缓蚀剂对污水处理系统腐蚀行为的作用效果。方法通过工艺流程分析、腐蚀形貌观察、腐蚀产物成分分析、腐蚀失重测试等手段,分析污水处理系统腐蚀原因,考察油田化学添加剂对SSF污水处理系统腐蚀行为的影响。结果输送介质中溶解的二氧化碳、高浓度氯离子、氧是导致SSF净化装置内腐蚀的主要原因。分别添加质量浓度为150、0.3、60 mg/L的净水剂、絮凝剂、助凝剂后,动态腐蚀速率可从1.8544 mm/a降到0.6674、0.8627、0.3530 mm/a,静态腐蚀速率可从1.2515 mm/a降到0.9565、0.9474、0.6256 mm/a。添加160 mg/L缓蚀剂,动态腐蚀速率从1.8544 mm/a降低到0.0822 mm/a,静态腐蚀速率从1.2515 mm/a降低到0.0238 mm/a。同时添加净水剂、絮凝剂、助凝剂三种药剂,动态腐蚀速率为0.7672 mm/a,静态腐蚀速率为0.8742 mm/a;同时添加净水剂、絮凝剂、助凝剂、缓蚀剂四种药剂,动态腐蚀速率为0.3069 mm/a,静态腐蚀速率为0.0263 mm/a。结论添加缓蚀剂能有效控制SSF污水处理系统内腐蚀。污水处理用净水剂、絮凝剂、助凝剂对腐蚀有一定抑制作用。在动态条件下,净水剂、絮凝剂、助凝剂降低了缓蚀剂的缓蚀效果,在静态条件下,三种添加剂对缓蚀剂的缓蚀效果影响较小。

Effect of Oilfield Chemical Additives on Corrosion Behavior of Sewage Treatment System

The work aims to study the effect of water purifying agent, flocculant, coagulant aid and corrosion inhibitor on the corrosion behavior of sewage treatment system. Process flow analysis, corrosion appearance observation, corrosion product composition analysis and corrosion weight loss test were conducted to analyze the causes of corrosion in the sewage treatment system and investigate the influences of oilfield chemical additives on the corrosion behavior of SSF sewage treatment system. The results showed that the corrosion in SSF purification unit was caused by dissolved oxygen, carbon dioxide, high concentration chloride ions in the produced water. The dynamic corrosion rate decreased from 1.8544 mm/a to 0.6674 mm/a, 0.8627 mm/a, 0.3530 mm/a and the static corrosion rate decreased from 1.2515 mm/a to 0.9565 mm/a, 0.9474mm/a and 0.6256 mm/a after adding water purifying agent, flocculant and coagulant aid with concentration of 150mg/L, 0.3mg/L and 60mg/L respectively. After adding 160 mg/L corrosion inhibitor, the dynamic corrosion rate decreased from 1.8544 mm/a to 0.0822 mm/a, and the static corrosion rate decreased from 1.2515 mm/a to 0.0238 mm/a. The dynamic corrosion rate was 0.7672 mm/a and the static corrosion rate was 0.8742 mm/a after adding water purifying agent, flocculant and coagulant aid at the same time. But the dynamic corrosion rate was 0.3069 mm/a and the static corrosion rate was 0.0263 mm/a after adding water purifying agent, flocculant, coagulant aid and inhibitors at the same time. Adding corrosion inhibitor can effectively control the corrosion in SSF sewage treatment system. Water purifying agent, flocculating agent and coagulant aid can inhibit the corrosion to some extent. Under the dynamic condition, water purifying agent, flocculating agent and coagulant aid reduce the inhibition effect of the inhibitor, but under the static condition, the three additives have little effect on the inhibition effect.