【作者】 张永强；

【导师】 高宝玉；

【作者基本信息】 山东大学 ， 环境工程， 2010， 硕士

【摘要】 随着聚合物驱油技术的发展,大幅的提高了原油的采收率,但也产生了大量的采油污水。聚合物驱采出水中,聚丙烯酰胺(HPAM)含量高,粘度大,乳化程度高,油水分离困难,原油的处理水驱采出水的“老三套”工艺不能满足聚合物驱采出水的处理要求,针对这种情况,本文提出了“混凝-水解酸化-动态膜生物反应器”(前置混凝)组合工艺和“水解酸化-动态膜生物反应器-混凝”(后置混凝)组合工艺。在比较不同单一混凝剂的除油、除浊效果基础上,进行了混凝剂的优化复配,并研究了铝盐混凝剂处理聚合物驱采出水的机理和混凝剂处理聚合物驱采出水的混凝动力学。在组合工艺的研究中,通过实验确定了混凝剂的最佳投加量,水解酸化反应器的最优水力停留时间以及动态膜生物反应器周期运行的规律,通过组合工艺的连续30天运行,探讨了其处理聚合物驱采出水的可行性,所得结论主要有：(1)混凝法处理胜利油田坨一站聚合物驱采出水时,传统铝盐铁盐混凝剂除油效果优于无机高分子混凝剂和有机高分子絮凝剂,FC(以Fe计)和AC(以Al2O3计)按投加量质量比1：3混合复配,可以实现铁铝混凝剂缺点互补。无机复配铁铝混凝剂(FC：AC=1：3)与有机絮凝剂三元复配时,除油效果主要决定于无机混凝剂的投加量；投加量为0.5 mg／L的APAM便能使絮体进一步发生桥联,提高沉降性,减少污泥体积。(2)无机铝盐混凝剂处理聚合物驱采出水时,混凝效果主要依靠Al3+与水中残余HPAM交联作用,采出水中油滴和盐均会阻碍铝盐与HPAM的交联反应。与HPAM交联能力较强的AC处理采出水的效果较PAC处理效果好。在聚合物驱采出水中原油、聚合物、盐三者共存时,相互作用的结果都导致了铝盐混凝剂投加量增加,除油率和HPAM去除率降低。通过对无机混凝剂与聚合物驱采出水混凝动力学研究发现,复配铁铝混凝剂在提高混凝效果的同时絮体粒径没有明显下降。无机混凝剂与聚合物驱采出水中HPAM发生作用以化学键相连,产生的絮体具有较高的强度,不易破碎。(3)“混凝-水解酸化-动态膜生物反应器”组合处理工艺经实验运行30 d,首先以140 mg／L的复配铁铝混凝剂进行混凝,水解酸化池的最佳停留时间为8 h,动态膜生物反应器的出水水头为5 cm,周期时间约为140 h。经过运行参数优化之后,整套工艺可以平稳运行。组合工艺稳定运行30天,经过混凝处理后,进水COD平均612.4 mg／L降为168.9 mg／L,经过水解酸化处理后,COD下降至147.7mg／L,经好氧生物处理阶段,COD进一步降到79.7 mg／L,出水COD稳定,可以达到1998年以前建设单位的一级排放标准,以及1998年以后建设单位的二级排放标准。其他污染物指标均可以满足1998年以后建设单位的一级排放标准。在进水氨氮平均27.3 mg／L时,经过混凝处理、水解酸化、好氧生物处理后,氨氮降到1.5 mg／L,达到1998年以后建设单位的一级排放标准。(4)“水解酸化-动态膜生物反应器-混凝”组合工艺经实验运行后,水解酸化池的最佳停留时间为12 h,动态膜生物反应器的出水水头为5 cm,周期时间约为140 h,后置混凝工艺混凝剂投加量为120 mg／L,经过运行参数优化之后,整套工艺可以平稳运行。组合工艺稳定运行30天,在进水COD平均627.7 mg／L时,经过水解酸化处理后,COD下降至570.9 mg／L,经好氧生物处理阶段,COD进一步降到476.6 mg／L,经混凝工艺后,COD最终为75.9 mg／L,出水稳定,可以达到1998年以前建设单位的一级排放标准,以及1998年以后建设单位的二级排放标准。在进水氨氮平均29.8 mg／L时,经过水解酸化、好氧生物处理、混凝处理后,氨氮降到1.6 mg/L,达到1998年以后建设单位的一级排放标准。“水解酸化-动态膜生物反应器-混凝”组合工艺的提出虽然在实际的应用中存在不足,但随着聚合物驱采出水性质的变化、HPAM降解菌以及新生物工艺的研究,“水解酸化-动态膜生物反应器-混凝”组合工艺也提出了一种主要依靠生物法处理聚合物驱采出水的新思路。更多还原

【Abstract】 With polymer flooding applied to enhance oil recovery and increase oil production in many oilfields, large amount of wastewater has been produced. The produced water from polymer flooding contains a quantity of residual hydrolyzed polyacrylamide (HPAM), which seriously impedes the oil-water separation. The old wastewater treatment process in the oilfield cannot meet the standard in treating produced wastewater from polymer flooding. The combined method "coagulation-hydrolysis acidification-dynamic membrane bioreactor" and "hydrolysis acidification-dynamic membrane bioreactor-coagulation" processes were developed.The applicable coagulants were chosen and compounded based on the comparison of the single coagulation effect of each coagulant at first. The coagulation mechanism of produced wastewater from polymer flooding by aluminum salt coagulants and the coagulation dynamics of different coagulates were studied. In the combined processes, the optimal dosage of the coagulant, the optimal hydraulic retention time in hydrolysis acidification reactor and the rule in dynamic membrane bioreactor operating were determined. As the combined processes running for 30 days, the feasibility of discharging the produced wastewater from polymer flooding was examined.The main contents and results are as follows:When the produced wastewater from polymer flooding was treated by coagulation method, the oil or turbidity removal efficiencies of traditional aluminum salt or iron salt coagulants were much better than those of the inorganic polymer coagulants or organic polymer flocculants. When the aluminum chloride (AC) and iron chloride (FC) were compounded with the dosage mass ratio of 1:3, it could not only improve the settling performance and decrease the volume of sludge, but also obtained high oil and turbidity removal efficiencies. When the compounded aluminum-iron coagulant was compounded with anionic polyacrylamide (APAM), the oil and turbidity removal efficiencies were dominated by the dosage of the inorganic compounded aluminum-iron coagulant. And at the dosage of 0.5 mg/L, APAM could bridge the flcos and improve the settling performance and decrease the volume of sludge.When the actual wastewater was treated by aluminum salt coagulants, the mainly removal effect was the crosslinking action between Al3+ and residual HPAM in the produced wastewater. But the crosslinking action could be hindered by the crude oil and salt. Aluminum sulfate had better efficiencies of removing oil and HPAM because of the better crosslinking action with HPAM. The dosages were increased and the treatment effects were reduced as crude oil, HPAM and salt existing in the wastewater.The flcos size was not decreased when compounded aluminum-iron coagulant reacted with the produced wastewater in the coagulation dynamics research. Inorganic coagulant bonded with HPAM in produced wastewater from polymer flooding through chemical bond, so the flcos were steady and not easy to be broken.The combined process of "coagulation-hydrolysis acidification-dynamic membrane bioreactor" was operated for 30 days. The optimal operation parameters were as follow:the dosage of compounded aluminum-iron coagulant was 140 mg/L, the HRT in hydrolysis acidification reactor was 8 h and the head drop of dynamic membrane bioreactor was 5 cm with 140 h running cycle. The results showed that the combined process was stable after optimizing the operation parameters. After coagulation, COD could decrease from 612.4 mg/L to 168.9 mg/L. After hydrolysis acidification, the COD fell to 147.7 mg/L. After aerobic biological process, the COD reduced to 79.7 mg/L. The COD of effluent could steadily reach the class I National Wastewater Discharge Standard before 1998, and the class II National Wastewater Discharge Standard after 1998. The average concentration of NH3-N in influent was 27.3 mg/L, after the combined coagulation, hydrolysis acidification and dynamic membrane bioreactor processes, the concentration decreased to 1.5 mg/L, and could steadily reach the class I National Wastewater Discharge Standard after 1998.The combined process of "hydrolysis acidification-dynamic membrane bioreactor-coagulation" was operated for 30 days. The optimal operation parameters were as follow:the HRT in hydrolysis acidification reactor was 12 h, the head drop of dynamic membrane bioreactor was 5 cm with 140 h running cycle and the dosage of compounded aluminum-iron coagulant was 120 mg/L. The results showed that the combined process was stable after optimizing the operation parameters. After hydrolysis acidification, COD could decrease from 627.7 mg/L to 570.9 mg/L. After aerobic biological process, the COD fell to 476.6 mg/L. After coagulation, the COD reduced to 75.9 mg/L. The COD of effluent could steadily reach the class I National Wastewater Discharge Standard before 1998, and the classⅡNational Wastewater Discharge Standard after 1998. The average concentration of NH3-N in influent was 29.8 mg/L, after the combined coagulation, hydrolysis acidification and dynamic membrane bioreactor processes, the concentration decreased to 1.6 mg/L, and could steadily reach the class I National Waste water Discharge Standard after 1998. In despite of the shortcoming of "hydrolysis acidification-dynamic membrane bioreactor-coagulation" process, it provided a new biological method to treat produced wastewater from polymer flooding with the development of produced wastewater, the HPAM degrading bacteria and the new biological technology.更多还原