Milt Beychok
12-29-2007, 09:07 PM
An API oil-water separator is a device designed to separate gross amounts of oil and suspended solids from the wastewater effluents of oil refineries, petrochemical plants, chemical plants, natural gas processing plants and other industrial sources. The name is derived from the fact that such separators are designed according to standards published by the American Petroleum Institute (API). Below is a schematic diagram and description of such a separator:
http://www.air-dispersion.com/API Separator.png
The API separator is a gravity separation device designed by using Stokes Law to define the rise velocity of oil droplets based on their density and size. The design of the separator is based on the specific gravity difference between the oil and the wastewater because that difference is much smaller than the specific gravity difference between the suspended solids and water. Based on that design critrion: most of the suspended solids will settle to the bottom of the separator as a sediment layer, the oil will rise to top of the separator and the wastewater will be the middle layer between the water on top and the solids on the bottom.
Typically, the oil layer is skimmed off and subsequently re-processed or disposed of, and the bottom sediment layer is removed by a chain and flight scraper (or similar device) and a sludge pump. The water layer is sent to further treatment consisting usually of a dissolved air flotation (DAF) unit for further removal of any residual oil and then to some type of biological treatment unit for removal of undesirable dissolved chemical compounds.
(This is an excerpt from an article which I created in the online Citizendium (http://en.citizendium.org/wiki/API_oil-water_separator) and the schematic diagram was also created by me.)
http://www.air-dispersion.com/API Separator.png
The API separator is a gravity separation device designed by using Stokes Law to define the rise velocity of oil droplets based on their density and size. The design of the separator is based on the specific gravity difference between the oil and the wastewater because that difference is much smaller than the specific gravity difference between the suspended solids and water. Based on that design critrion: most of the suspended solids will settle to the bottom of the separator as a sediment layer, the oil will rise to top of the separator and the wastewater will be the middle layer between the water on top and the solids on the bottom.
Typically, the oil layer is skimmed off and subsequently re-processed or disposed of, and the bottom sediment layer is removed by a chain and flight scraper (or similar device) and a sludge pump. The water layer is sent to further treatment consisting usually of a dissolved air flotation (DAF) unit for further removal of any residual oil and then to some type of biological treatment unit for removal of undesirable dissolved chemical compounds.
(This is an excerpt from an article which I created in the online Citizendium (http://en.citizendium.org/wiki/API_oil-water_separator) and the schematic diagram was also created by me.)