利用混凝-超滤膜法研究乳化油水的分离过程

摘要

实验主要考察混凝-超滤膜法联用处理油田采出水中乳化油的效果.选用三种混凝剂Al2(SO4)3,FeCl3,AlCl3用于预处理过程,通过改变混凝剂用量和进料液性状来筛选出效果优异的混凝剂,并对超滤膜在处理过程中操作参数的选择及膜污染情况进行了研究.结果表明三氯化铁对处理一定范围内pH值和温度的油田采出水有更好的适应性,对浊度及TOC(总有机碳)的去除效果也最好,TOC去除率达96%以上,但TOC的最终含量在23 mg·L-1.通过考察膜通量、TOC含量和浊度值以及借助SEM表面微观分析手段,发现混凝-超滤膜法的联用不仅可以使TOC的最终含量降低到13 mg·L-1以下,达到油田回注水的水质要求,而且还可以减轻膜污染程度,保证膜通量在一段时间内的稳定性.%Oil removal of oil/water emulsion from oilfield was studied via integration of coagulation and ultrafiltration. The effectiveness of coagulation prior to ultrafiltration was studied by three different coagulants (Al2(SO4)3, FeCl3 and AlCl3) and the most effective coagulant was selected by varying coagulant dosages and feed solution properties. Effects of operating conditions on membrane performance and fouling of membrane were also investigated. The result shows that FeCl3 is the best coagulant studied in a wide range of pH and temperatures. It also demonstrates the best performance in improving feed water quality in terms of turbidity and TOC (total organic carbon). The TOC removal rate is 96%, although the ultimate TOC concentration is above 23 mg·L-1. Results of membrane flux, TOC, turbidity and membrane surface show that the coupled process reduces final TOC content to <13 mg·L-1, which meets the required water quality standard for rejection.Moreover, it also remarkably reduces membrane fouling, and can maintain membrane flux stability for a long period.