Oil/water separators are vessels used for the separation of LNAPL (light non-aqueous phase liquids) and DNAPL (dense non-aqueous phase liquids) from water. Also known as coalescers, oil/water separators rely on the close surfaces of coalescing media within the vessel to increase the efficiency of the natural tendency of liquids of differing specific gravities to separate. These vessels are mainly used for separation of oil and water, but can also be used to separate water from chlorinated solvents, which have a higher specific gravity than water.
The media within an oil/water separator is generally constructed of materials that are water-repelling and oil-attracting, like PVC and polypropylene. When droplets of oil contact the media, they become attached to the surface. As the media becomes coated with oil, the small droplets coalesce into bigger droplets and begin to migrate upward. When they reach the surface the larger droplets separate from the media and float on the surface of the separation chamber. As more oil collects on the surface, two distinct layers of liquid form, one of oil and one of water. An adjustable skimmer is used to collect the oil from the surface and transfer to a storage vessel.
The same principle applies to liquids that are more dense than water, except the DNAPL will collect at the bottom of the oil/water separator, rather than the top.
The design of an oil/water separator is dependent on the types and densities of the liquids to be separated and the required flow rate.
MLE Equipment manufactures oil/water separators, allowing for customizable design. Please see the provided specification sheets and manuals for more detailed information on oil/water separators.
