低强度旋流气浮处理含油污水实验研究

Experimental study of low intensity cyclone flotation on wastewater treatment

低强度旋流气浮技术是基于弱离心力场的非常规气浮技术,利用离心力强化油滴与气泡的碰撞、黏附,可提高浮选效率。为了优化低强度旋流气浮的浮选性能,研究旋流强度、含油量、回流比和气泡注入方式（顺流、逆流）对浮选性能的影响。结果表明：旋流场处于低雷诺数湍流运动时,气泡与油滴能高效地完成碰撞、黏附、浮升,同时可避免湍流对气泡-油滴聚合体稳定性的破坏;低强度旋流浮选时,气浮筒对水力波动的适用能力强,且能有效地处理低含油量污水;气浮筒在顺流或逆流时具有不同的最优浮选区间,当入口旋流强度为17.0 g（顺流）或13.0 g（逆流）时,浮选效果最佳,当含油量为500 mg/L,回流比为20%～35%（顺流）或30%～35%（逆流）时,除油效率不低于75%。

Low intensity cyclone flotation is an unconventional flotation based on low intensity centrifugal force field, which uses centrifugal force to enhance the collision and adherence between oil droplet and bubble, and therefore improves the flotation efficiency. To optimize the separation performance of low intensity cyclone flotation, the influences of swirl intensity, oil content, reflux ratio, bubble injection method（ downstream, upstream） on the flotation performance were studied. The results show that, when the swirl flow field is turbulent flow of low Reynolds number, the oil droplets can collide and adhere with the bubbles effectively, and then can avoid the destruction of the oil droplet-bubble polymer caused by the high intensity turbulent flow. The performance of downstream flotation is different from one of upstream flotation. The low intensity cyclone flotation unit has strong ability to adapt to hydraulic fluctuations, and can treat wastewater of low oil content effectively. The optimum operating condition of cyclone flotation unit is： when the inlet centrifugal acceleration is 17.0 g（downstream） or 13.0 g （upstream）, oil content is 500 mg/L, reflux ratio is 20% -35% （downstream） or 30% -35% （upstream）, the oil removal rate is not less than 75 %.