稠油热采污水预氧化工艺结垢机理及阻垢研究

Study on pre-oxidation fouling mechanism and scale inhibition of heavy oil thermal recovery sewage station

为解决稠油热采污水站采用预氧化工艺后污水易结垢问题,采用实验测试与理论分析方法,分析了污水采用预氧化工艺后的结垢机理,评价了聚丙烯酸、水解聚马来酸酐等6种阻垢剂的阻垢性能与复配方案。结果表明,高含成垢离子的污水经预氧化流程后,pH值升高,CaCO3结垢反应向晶体析出的方向移动,促进了垢的生成;模拟水中,PAA单剂以12 mg/L注入时阻垢率为82.3%,KR928以10 mg/L注入时阻垢率为92.4%;HPMA与PAA按1∶2复配后以15 mg/L注入,阻垢率在85%以上;复配阻垢剂在真实水样中阻垢率虽有所降低,但仍在80%以上;聚马来酸酐与聚丙烯酸复配的阻垢剂可有效抑制稠油热采污水因采用预氧化工艺引起的结垢。

The heavy oil thermal recovery sewage station adopts the pre-oxidation process and the sewage is easy to scale.The experimental and theoretical analysis methods were used to analyze the fouling mechanism of the pre-oxidation process of wastewater,and the scale inhibition performance and compounding scheme of six scale inhibitors such as polyacrylic acid and hydrolyzed polymaleic anhydride were evaluated.The results show that the pH value of the sewage containing high scale-forming ions increases after the pre-oxidation process,and the CaCO3 scale reaction moves to the direction of crystal precipitation,which promotes the formation of scale.In the simulated water,the PAA single agent is inhibited by the injection of 12 mg/L,the rate was 82.3%.When KR928 was injected at 10 mg/L,the scale inhibition rate was 92.4%.HPMA and PAA were mixed at 1∶2 and then injected at 15 mg/L.The scale inhibition rate was above 85%.The compound scale inhibitor was real.Although the scale inhibition rate in water samples is lower,it is still above 80%;the scale inhibitor of polymaleic anhydride and polyacrylic acid can effectively inhibit the scaling caused by the pre-oxidation process of heavy oil thermal recovery sewage.