Abstract: Based on the dissolved⁃air flotation process, a multiphase flow mixture model numerical simulation was established to simulate the pressure field distribution, particles trace characteristics and the removal effect of oil and suspended matter in the process of settlement separation of produced water by air flotation, the influence of air flotation on the characteristics of the settlement separation flow field of produced water is revealed by comparing with the characteristics of conventional gravity settlement separation. The results indicate that the more stable pressure field distribution is obtained by the sedimentation with dissolved⁃air flotation through adapting the change of treatment amount, and relatively stable and orderly motion tracks of oil droplets and suspended particles with uniform distribution in the flow field are obtained by avoiding vortexing. The removal rates of oil and suspended solids under simulated conditions are increased by 8%~11% compared with the conventional gravity sedimentation separation, and the improvement of the settlement separation effect of produced water was effectively ensured. The construction of the adaptability of air flotation process and the basis of improving the efficiency of produced water treatment are provided by the understanding of the flow field characteristics in the settlement separation of air flotation.

Key words: Dissolved?air flotation, Settlement separation, Pressure field, Particles trace, Produced water, Numerical simulation

摘要： 以溶气气浮沉降工艺为对象，基于多相流混合模型数值模拟描述了含油污水气浮选沉降分离过程中的压力场分布、粒子运动迹线特征及除油、除悬浮物效果，并与普通重力沉降分离特性进行对比，揭示了气浮选对含油污水沉降分离流场特性的影响。结果表明，溶气气浮沉降能够适应处理量变化而获得更为稳定的压力场分布，能够避免涡流而取得相对稳定有序且在流场空间分布均匀的油珠、悬浮物粒子运动轨迹，模拟条件下的除油率和悬浮物去除率较普通重力沉降分离时提高8%~11%，有效改善了含油污水沉降分离效果,为气浮选工艺适配性构建及含油污水提效处理提供了依据。

关键词: 溶气气浮, 沉降分离, 压力场, 粒子迹线, 采出污水, 数值模拟