【作者】 张雷；

【导师】 刘惠玲；

【作者基本信息】 哈尔滨工业大学 ， 环境科学与工程， 2014， 博士

【摘要】 伴随着三元驱采油技术应用而产生的三元复合驱采油污水既保持了常规油田污水特性,由于聚合物、表面活性剂以及碱的加入又促其显示出了其独有的性质。碱对地层粘土矿物溶蚀作用导致水中以硅为首的悬浮固体含量高;水中大分子聚合物溶解导致水体粘度高,沉降过滤处理难度大;表面活性剂存在导致水体Zeta电位绝对值高,破乳絮凝困难。上述污水特性导致传统三元驱污水处理工艺中各设备均出现不适应,絮凝剂作用效果差,聚结除油器破乳聚结除油效率低,石英砂过滤器滤料板结流失,悬浮固体去除效果差,导致工艺出水水质难以稳定达标。污水处理过程投加大量的絮凝剂,形成大量含有絮凝剂含油污泥,油泥处理难度大。通过室内试验筛选确定无机聚合硫酸铁和有机UT6-4絮凝剂,复配质量比例500:40处理三元驱采油污水用絮凝效果最佳。利用室内模拟装置研究了超声强化降解聚合物降低水体粘度效果,在(40k Hz+28k Hz+20k Hz)正交三场作用下,控制声强1.5W·cm-2,臭氧投加量7.5mg/L,作用时间15min,降解聚合物后粘度变化率可达到86.1%。臭氧氧化降解聚合物过程中引入超声,强化了臭氧传质效果,促进臭氧分解产生更大量的22OH和?OH,比单独臭氧氧化效率提高3倍以上。降解过程中污水中油与聚合物存在降解竞争效应,采用超声强化臭氧氧化降解聚合物污水含油量不宜高于100mg/L。基于室内试验结果,提出了混凝沉降—双向聚结除油—超声强化降解聚合物—两级过滤工艺,针对除油器和过滤器存在问题,优化设备结构,开发新型除油器和过滤器。依据聚结除油理论,利用颗粒状聚结材料具有高效碰撞聚结作用,同时强化其润湿聚结作用,理论计算聚结除油参数,优选聚结材料,优化除油器内部结构,设置反冲洗系统,开发了双向聚结除油器。利用超声强化臭氧氧化降粘同时辅以搅拌式过滤器形成的湍流流场破坏滤料板结层,优化滤层级配,开发搅拌式双层滤料过滤器。基于以上研究了混凝沉降+双向流除油器+超声强化臭氧氧化降粘+两级过滤工艺处理三元驱采油污水效能,确定超声强化臭氧氧化装置是工艺核心,其运行状态下出水水质稳定达标。在来水含油平均847.24mg/L,悬浮固体159.06mg/L条件下,出水油仅为5.01mg/L,悬浮固体仅为9.93mg/L,油和悬浮固体去除率分别达到了99.39%和93.21%,出水稳定达到回注水油和悬浮固体≤20mg/L标准,采用该工艺处理污水其成本较现有工艺减少1/3。三元驱采油污水处理过程中形成的沉降罐底泥含油量高,具有回收价值。同时重质油含量高,以微小无机颗粒为中心形成稳定乳化油,从污泥中脱出回收油难度大。为达到大庆油田规定污泥含油污泥资源化再利用含油量低于2%要求这一标准,采用超声破乳气浮强化除油这一关键技术处理经过高温热化学清洗后含油污泥,利用超声空化作用降低乳化界面膜强度,促进“水粒子”聚合实现破乳除油。开发含油污泥处理工艺控制高温热化学清洗时间40min,清洗剂加药量1%,热水温度60℃,在超声作用20min,破乳剂投加量10mg/L,实现污泥中油的去除,投加2%复配聚合硫酸铁和UN6-4絮凝剂,离心机转速2500r/min脱水,脱水后污泥含水≤80%,含油≤2%。将离心脱水后污泥残渣与水泥,粉煤灰,膨润土,离子添加剂按照质量比1:0.2:0.3:0.3:0.005条件混合进行固化试验,制做路面砖。固化后产品强度达到3.89MPa,达到混凝土路面砖设计标准。对固化后产品进行浸出试验评价其毒性,浸出时间120h,浸出液的含油量3mg/L以下,低于国家污水排放一级B标准,有毒有害金属离子未检出,路面砖产品安全。通过上述工艺处理含油污泥实现油回收同时控制污泥二次污染,实现污泥资源化利用。利用超声强化臭氧氧化降解聚合物技术辅以双向聚结除油器和搅拌式多介质过滤器开发的三元驱采油污水工艺实现三元驱采油污水达标处理回注。采用高温热洗超声强化除油技术去除污泥中油,在污泥含油2%以下采用固化技术制做路面砖,回收油泥中油同时实现污泥资源化。有效解决三元驱采油处理过程中污水和污泥处理系统存在问题,促进三元驱采油技术推广应用。更多还原

【Abstract】 The produced water from ASP(Alkali,Surfactant and Polymer) flooding oil recovery process contained polymer, surfactant and alkali, which was hard to be removed by the traditional treatment process. Furthermore, lots of flocculants were added during the ASP process, which produced a large amount of refractory oily sludge.Compared with produced water from polymer process, the produced water from ASP process has several different characteristics: Firstly, it had higher suspended solids(SS) concentration due to the dissolution of clay mineral; secondly, it had higher viscosity because of the presence of polymer residues, which made the separation of oil and water even harder; In addition, the surfacta nts in effluent hinders the demulsification and flocculation process. Thus, the traditional process failed to treat the ASP effluent effectively, which reduced the coalescence demulsification efficiency and lost the filter material.In a new laboratory study, the inorganic PFS and organic UT-4 were chosen as the flocculant to treat the ASP effluent at the proportion of 500:40. The degradation of polymer by using ultrasonic enhanced O3 oxidation was also performed in(40k Hz+28k Hz+20k Hz) three orthogonal field with the intensity of 1.5w/m2 and the addition of 7.5mg/L O3 for 15 min. The variance ratio of dynamic viscosity could attain 86.1%. The competition effect in the degradation process was found between the polymer and oil, thus the oil concentration in the effluent could be controlled below 100mg/L after the treatment.The process for treating the ASP effluent was consisted by coagulation sedimentation, coalescence oil removal device, ultrasonic enhanced O3 oxidation degradation of polymer and two stage filtration. Among them, the novel coalescence oil removal device and filter were developed to enhance the treating efficiency. Based on the theoretical calculation, the two-way coalescence oil removal equipment was also designed by optimizing coalescence mate rial, improving the internal structure and setting up the backwashing system. The double-layer stir filter was developed by using the agitator structure to break the material with the application of ultrasonic enhanced O3 oxidation degradation of polymer to reduce viscosity.After the treatment, the oil and SS in the effluent was decreased from 847.24mg/L and 159.06 mg/L to 5.01 mg/L and 9.93 mg/L. The oil and SS removal rate reached 99.39% and 93.21%, respectively. The treatment cost of new process was reduced by 1/3 than the traditional process.The excess sludge produced during the ASP process had high oil content,which was mostly heavy oil. The inorganic impurities in sludge were mainly composed by Fe and Al from the flocculation components, which emul sified the oil and made it difficult to separate from sludge. To meet the oil sludge recycle standard(oil concentration <2%), the detergents of sodium silicate and sodium dodecyl sulfate with hot water, as well as the ultrasonic demulsification device were applied for the removal of oil from sludge. The oil sludge were firstly treated by the thermal chemical cleaning process for 40 min, cleaning agent dosage was 1%, water temperature was 60℃. After that, the ultrasonic treatment process was conducted for 20 min. For separating the water from sludge, a centrifuge device was applied with the addition of 10 mg/L demulsifier and 2% flocculation dose, the centrifuge speed was 2500 r/min. After the treatment, the oil and water content in the sludge was less than 2% and 80%, respectively.The reuse of sludge residue by producing bricks was also studied in this work. The proportion of sludge, cement, fly ash, bentonite and ion addition was 1:0.2:0.3:0.3:0.005. After immobilization, the strength of the product was 3.89 Mpa, which met the concrete pavement standard. After 120 h leaching, the oil content in the leaching liquid was lower than 3 mg/L, no poisonous and harmful material were detected.The novel treatment process of ASP produced water based on ultrasonic techniques could attain promising efficiency and the water quality could meet the reinjection water standard. The oil in excess sludge could also be removed by the high temperature cleaning-ultrasonic process, the oil concentration in sludge residue was lower than 2% after treatment. The sludge residues were further reused for the brick production by using immobilized technology. In general, the effluent and excess sludge of the ASP process could be treated effectively, which facilitated the application of ASP flooding oil recovery technology.更多还原