Oil–water separator
An oil–water separator (OWS) is a piece of equipment used to separate oil and water mixtures into their separate components.
API oil–water separator
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).[1]
Oily water separator (marine)
The purpose of shipboard oily water separator (OWS) is to separate oil and other contaminants that could be harmful for the oceans. They are most commonly found on board ships where they are used to separate oil from oily waste water such as bilge water before the waste water is discharged into the environment. These discharges of waste water must comply with the requirements laid out in Marpol 73/78.
Bilge water is a near-unavoidable product of shipboard operations. Oil leaks from running machinery, such as diesel generators, air compressors, and the main propulsion engine. Modern OWSs have alarms and automatic closure devices which are activated when the oil storage capacity of the oil water separator has been reached.
Downhole oil–water separation
Downhole oil–water separation (DOWS) technology is an emerging technology that separates oil and gas from produced water at the bottom of the well, and re-injects most of the produced water into another formation which is usually deeper than the producing formation, while the oil and gas rich stream is pumped to the surface. DOWS effectively removes solids from the disposal fluid and thus avoids injectivity impairment caused by solids plugging. Simultaneous injection using DOWS minimizes the opportunity for the contamination of underground sources of drinking water (USDWs) through leaks in tubing and casing during the injection process.
Gravity plate separator
A gravity plate separator contains a series of oleophilic plates through which the contaminated water flows. The oil in the water coalesces on the underside of the plate eventually forming droplets before coalescing into liquid oil which floats off the plates and accumulates at the top of the chamber. The oil accumulating at the top is then transferred to waste oil tank on the vessel where it is later discharged to a treatment facility shore side. This type of oily water separator is very common in ships but it has some flaws that decrease efficiency. Oil particles that are sixty micrometers or smaller do not get separated. The variety of oily wastes in bilge water can limit removal efficiency especially when very dense and highly viscous oils such as bunker oil are present. Plates must be replaced when fouled, which increases the costs of operation.[2]
Electrochemical
Wastewater purification of oils and contaminates by electrochemical emulsification is actively in research and development. Electrochemical emulsification involves the generation of electrolytic bubbles that attract pollutants such as sludge and carry them to the top of the treatment chamber. Once at the top of the treatment chamber the oil and other pollutants are transferred to a waste oil tank.[3]
Bioremediation
Bioremediation is the use of microorganisms to treat contaminated water. A carefully managed environment is needed for the microorganisms which includes nutrients and hydrocarbons such as oil or other contaminates, and oxygen.
In pilot scale studies, bio-remediation was used as one stage in a multi-stage purification process involving a plate separator to remove the majority of the contaminants and was able to treat pollutants at very low concentrations including organic contaminates such as glycerol, solvents, jet fuel, detergents, and phosphates. After treatment of contaminated water, carbon dioxide, water and an organic sludge were the only residual products.[4]
Centrifugal oily water separator
A centrifugal water–oil separator, centrifugal oil–water separator or centrifugal liquid–liquid separator is a device designed to separate oil and water by centrifugation. It generally contains a cylindrical container that rotates inside a larger stationary container. The denser liquid, usually water, accumulates at the periphery of the rotating container and is collected from the side of the device, whereas the less dense liquid, usually oil, accumulates at the rotation axis and is collected from the center. Centrifugal oil–water separators are used for waste water processing and for cleanup of oil spills on sea or on lake. Centrifugal oil–water separators are also used for filtering diesel and lubricating oils by removing the waste particles and impurity from them.[5]
Hydrocyclone oily water separator
A hydrocyclone oily water separator is a device designed to separate oil and water by a cyclonic action. It contains a tapered pipe that takes in oily water from the top and via centrifugal forces spins out the oils from one exit point while the heavier water is ejected from the other end. Hydrocyclones are useful for removing a range of oil droplet sizes with broad applications across many industrial sites where oily water accumulates. The technology can also be applied to meat processing and dairy manufacturing applications where the recovery of animal fats may be re-used in the manufacture of tallow.
See also
References
- ↑ "American Petroleum Institute". 2015-05-19.
- ↑ Cincinnati, OARM. "Useful sites in addition to NSCEP". Retrieved 2015-06-03.
- ↑ "Separation and Purification Technology" (PDF). www.atmc.umassd.edu. Archived from the original (PDF) on 2015-09-24. Retrieved 2015-06-03.
- ↑ Cincinnati, OARM. "Useful sites in addition to NSCEP". Retrieved 2015-06-03.
- ↑ "Oil Water Separator Flow Process Description". Retrieved 2015-06-11.