A Guide to Oil Skimming - Choosing the Right Oil Skimmer


5H anchovy processing plantPlant personnel are always looking for new tools and equipment to help them run their facility more efficiently. In many manufacturing and processing plants, oily water is present, which prevents a plant from functioning efficiently.

Water has several purposes in a manufacturing or processing facility. It can be used for cooling machinery, washing down equipment or in processing. Sometimes, this water picks up oil or grease from surrounding machinery and equipment. Regardless of whether the facility chooses to reuse the water or send it to the city treatment plant, it has to remove the oil. Some plants, however, are not properly equipped to effectively remove oil.

An oil skimmer is the perfect solution. 

What is an Oil Skimmer?

An oil skimmer is a piece of equipment that removes oils, greases, animal fats from the surface wastewater so it can be collected into a separate oil container.  Oil skimmers are used in a wide variety of industries such as steel, biodiesel, manufacturing, food processing, wastewater treatment and utility. Though several industrial manufacturers produce wastewater, not every facility utilizes an oil skimmer. Below is a guide to knowing why an oil skimmer is needed and how to properly choose the correct skimmer.

The Benefits of Using an Oil Skimmer 

The obvious reason to use an oil skimmer is to remove oil from water. Aside from this, there are beneficial reasons for using an oil skimmer. Using an oil skimmer can save a plant both time and money.

  • Removed waste oil can be valuable to other industries that develop products with the waste oil. For example, industries with vegetable oils or animal fats, as a by-product, can provide this valuable oil to other industries to make products, like biodiesel, soap and animal feed. Waste petroleum oil can also be recycled and cleaned, and receive additives to help make new petroleum oil.
  • Some plants re-circulate their water after treatment, and some send it to a city treatment plant. Which ever is used, the removal of oil prior to treatment reduces costs and makes the treatment more efficient, often resulting in reduced surcharge.
  • Unlike time-consuming and costly manual skimming, an automatic oil skimmer continuously removes oil unattended.
  • The cost of an outside contractor to haul away oil is greatly reduced with the installation of an oil skimmer. Since an oil skimmer removes oil and not water, the facility is not charged for hauling away water. In addition, with the container collecting oil without water, it is possible that the oil has value, thus reversing the charge.
  • Using an oil skimmer prevents foul odors. When an oil layer forms on the water surface, it prevents oxygen from reaching the water, allowing anaerobic bacteria to grow. This bacteria causes the odor.
  • If oil is left to build up, it can potentially be a fire hazard. An oil skimmer helps reduce that threat by removing the oil.
  • Skimming can prevent clogs in lines and sprays by removing coolant’s tramp oil. This tramp oil removal maximizes the effect and life of the coolant, as well as increase the life of the tool.

What to Look for in an Oil Skimmer

Every oil skimmer is designed to do the same thing. However, not every oil skimmer will achieve the same results. There are certain features that an oil skimmer should have to operate at the maximum functional level.

  • An oil skimmer’s removal capacity should match the amount of oil that is generated. For example, a small oil skimmer should not be used to remove oil from an oil spill.
  • The oil skimmer should be able to skim under conditions where floating debris is present.
  • The oil skimmer should not require constant adjustments or supervision in order to operate continuously. This is especially essential for a plant that is faced with minimal staffing.
  • Difficulty and expense of installation should be considered.
  • The oil skimmer should adjust to liquid level fluctuations.
  • The oil skimmer should be constructed of a material that is compatible with the application.

Other Useful Products That Are Used With an Oil Skimmer

There are additional products and accessories to aid the oil skimmer. These products are designed to meet plant personnel’s unique removal needs.

  • A decanter is designed to return any water removed by the skimming process back to the skim tank. It is suggested to use a decanter in the following situations:
    • If the skimmed oil is frothy, as found in machine tool coolant, cold rolling mill coolant or parts washing solution. The decanter gives the solution a chance to separate from the removed oil and be returned to the solution reservoir, which conserves on solution loss and new solution purchases.
    • When the oil does not enter the skimming area for long periods of time, the oil skimmer continually operates to protect against excessive discharge. During these times when there is no oil present, the decanter prevents an accumulation of water in the storage tank.
    • Where oily waste disposal costs and/or oil reclamation costs need to be controlled. The decanter minimizes the quantity of water or solution accumulation in waste storage containers, thereby controlling costs.
  • Pre-fabricated mounting systems not only eliminate the need of expensive bridgework to install the skimmer, but it also provides safe and easy access to the oil skimmer.
  • Used in conjunction with the oil skimmer, vapor hoods are used when oil must be removed from areas where volatile organic compounds (VOCs) are present. Vapor hoods are used in such places as tanks and sumps.
  • Oil skimmers are sometimes needed in extreme cold weather conditions. In order for the removed oil to be warm and fluid for processing, the oil skimmer needs to be equipped with a heating device, such as a heat rod.

Waste oil does not have to be a burden to plant personnel. Using an oil skimmer assures that the oil will be easily removed, with minimal effort. With the right oil skimmer, a facility can effectively manage the oil, and save time and money.

Topics: coolants oil oil recovery oil removal skim oil wastewater water treatment why skim?

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