油水乳化液在疏水复合涂层网膜上破乳分离的实验研究

Experimental Research of the Demulsification of Oil-in-Water Emulsions by a Composite Coating Membrane

油水分离对于采油、炼油以及含油废水的处理有着重要的意义。采用喷涂-高温塑化的方法,在400目不锈钢网上复合PPS(聚苯硫醚)-PTFE(聚四氟乙烯)涂层,构造微米级细长纤维结构,形成了一种复合涂层网膜。该网膜具有良好的疏水性和亲油性,最大孔径<10μm,对乳化液具有破乳分离的功能。考察了渗透通量以及水包油型乳化液破乳分离效果的影响因素。实验结果表明这种膜对水包油型乳化液具有良好的分离效果,在0.4 mm膜厚下,压力小于70 kPa时,水中的含油量小于10 mg·L-1。渗透通量随压力的升高而增加,膜厚对其也有一定影响,但操作压力太高、膜的面层厚度太薄均不利于分离,料液初始浓度对破乳分离的影响则不太大。

Oil-water separation is of great significance for oil mining and refining, and for the treatment of oily wastewater. A new type of microporous membrane used for oil-water emulsion separation was prepared by a spray-plasticizing method. The composite PPS-PTFE coating layer was first deposited on the 400 mesh stainless steel screen and a micron thin fiber structure was then fabricated on top of the composite layer. The prepared membrane has a maximum pore diameter of less than 10 gm and demonstrates excellent hydrophobic and oleophilic properties, which may be used for oil-water emulsion separation. The result of the experiment shows that this membrane is great for the oil-water separation. When the thickness of the membrane is about 0.4 mm and the pressure difference is below 70 kPa, the content of oil in water after separation is less than 10 mg·L^-1. Effects of the operating pressure difference, the membrane thickness and emulsion composition on the membrane permeation flux and separation factors were investigated. It was found that, increasing operating pressure difference and reducing membrane thickness have negative effect on the separation of oil-water emulsions, while the primary oil concentration of the emulsion has less significant effect.