In various industrial operations, industrial facilities may use many different oils and hydrocarbons. All the waste oil that gets generated during different processes is usually washed off along with water. In order to have environmental safety, oil must always be separated from water before they are disposed of.
In few cases, your waste oil may contaminate your coolants and cutting fluids, which can always lower the efficiency of the machines and may cause lasting damage.
By using oil skimmers, you can separate oils and also hydrocarbons in a cost-effective way from denser fluids. We will try to define in this article what are oil skimmers and how do they work.
How does oil skimmer work?
As far as oil skimmers are concerned, it is a simple mechanical device that skims the fluid surface for removing the grease or floating oil by using certain skimming media. Based on specific applications, oil skimmer designs may vary.
Also, it uses various skimming media like disks, belts and ropes. Efficiency of your oil skimmers is generally based on 2 basic fluid principles:
- Specific gravity
The definition of specific gravity will be ratio between one fluid density and another reference fluid. Also, it is referred as relative density. Usually, water is taken as reference fluid, while for gas the reference fluid is air at normal room temperature.
Usually, oil and hydrocarbons have much lower specific gravity as compared to water. Therefore, when mixture of water and oil settles, oil floats on the water surface. This is considered as the first stage of water separation from oil.
- Surface tension
This is another principle based on which oil skimming is possible. Surface tension refers to affinity of molecules of fluid that they have with each other, as well as with other materials. Water and oil’s surface tension has different characteristics, which makes it possible to separate 2 fluids effectively.
Usually oil molecules will have lower affinity to water molecules. Thus, oil molecules will bond better with oil and all other materials rather than water. Thus, water and oil can be separated.
Various types of skimmers
- Weir oil skimmer
As on water surface, oil always floats hence weir skimmer can very effectively remove oil. Weir skimmers may have manual/automatic mechanism for height adjustment that helps maintain their efficiency.
- Oleophilic oil skimmer
Due to high affinity of Oleophilic materials with oils and grease, they will absorb oil molecules faster than water molecules. Oleophilic skimming media will ensure maximum oil collection from water.
- Non-oleophilic oil skimmer
Where oleophilic skimmers will not be appropriate then non-oleophilic material will be used. This may occur while cleaning fluids are like hot alkaline aqueous part washers.
- Belt oil skimmer
They are fixed in one location, work well while oil touches the belt, so if there is no touching, then no skim. As it is motor driven, they lift oil from the surface to wipe-off blades/scraper.
- Tube oil skimmer
They are also fixed in one location, but are on boom arm for reaching out to grab oil.