Abstract: General concentration, particle concentration and middle grain size distribution of oil droplets in oil-water gravity separator are measured, and rising behavior of oil droplets in different separating areas analyzed. The experimental result demonstrates that in the entrance area, oil-water mixture has larger turbulence and fully lognitudinal mixing, oil comparative concentration is above 0.9 where the area is higher than 100 mm. Oil concentration is high in tilting plate and flat plate area, where small oil droplets coalesce into large ones, their middle grain size obviously increases from 10 mm to larger than 30 mm at the height of 50 mm. The renewing velocity of oil film in the flat plate area is slow and its fluidity poor, which results in the coalescence effect is inferior to the tilting plate area. Flow field in the gravity sedimentation area is comparatively steady, where oil comparative concentration is about 0.4~0.6, large oil droplets have already reached the top oil layer and separated. In front of the oil separated plate there are revolved flow and back mixing phenomena, oil comparative concentration approximately increases by 0.02 and middle grain size increases by about 1 mm in partial areas.

Key words: oil-water gravity separation, flow behavior, droplet coalescence, separating behavior

摘要： 在测定油水重力分离器内分散相油滴的浓度、粒度及中位粒径分布的基础上，分析了各区域内油滴的浮升规律. 结果表明，入口区域油水混合液的湍流程度较大，两相存在较充分的纵向掺混，在100 mm高度以上区域，油相相对浓度均达到0.9以上；斜板和平板区域内油相浓度较高，小油滴聚结成大油滴，在50 mm高度处，中位粒径由10 mm升至30 mm以上；平板区域油膜更新速度较慢，流动性较差，聚结效果不及斜板区域；重力沉降区域内流场相对平稳，油相相对浓度多集中于0.4~0.6之间，大油滴已基本浮升至顶部油层得到分离；隔油板前方区域存在涡旋流，部分区域油相相对浓度约升高了0.02，中位粒径增大了1 mm左右，出现返混现象.

关键词: 水重力分离, 流动特性, 液滴聚结, 分离特性