An oil treater is a separator vessel with a fire tube immersed in the liquid fluid phase to separate water and gas from oil-water emulsions. It has an integrated free water knockout section to remove any non-entrained water and help reduce the fuel consumption. Treaters are typically located just before the oil sales storage tanks and operate at low pressures to produce stock tank oil. The oil-water emulsion is “said to be treated” to ensure the oil is of high-quality to meet oil pipeline and sales specifications.
Before we discuss the working principle of an oil treater, let us look at the different types of treaters.
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Types of Oil Treaters
- Vertical Treaters
The vertical treaters have traditional designs and are commonly used where there is moderate or no gas flow. They are better suited to treat and process a low volume of emulsions that have 27 API gravity or lighter oil and high-water content. - Horizontal Treaters
Horizontal treaters are commonly used to process a more substantial volume of emulsions with any API gravity. They are widely used in complex operations where water and oil weigh about the same. - Bucket Treaters
They are a popular model of treaters used to process medium to light oil emulsions. Bucket Treaters are equipped in the downstream near a free-water knockout to remove the remaining water in the emulsion. They are quite easy to use and have an operator-friendly design. - Packed Treaters
A packed treater offers an efficient oil flow. It is best suited for all types of emulsions, particularly for the hard-to-treat applications. - Electrostatic Treaters
Similar to a packed treater, an electrostatic treater uses electricity through a transformer to offer increased productivity. It is a 3-phase separator typically used to separate oil, water and gas. It provides the highest efficiency by nearly doubling the treating capacity of the emulsion.
Operating Principle of a Treater
All types of treaters work on the following general principle:

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- The emulsion enters the separator vessel, and gas is vented out the top.
- Any free water in the emulsion drops to the water section and dumped out the bottom to a produced water tank.
- Then, the emulsion is allowed to pass over the fire tubes and is heated to the required temperature. This process helps to coalesce the water droplets.
- The emulsion flows into the oil treating portion of the separator for the separating process. Some treaters also have an excelsior section or hay that serves as a filtering media to separate any solids from the oil.
- The equipment has dump valves that are used to control the height of the oil and water liquid phases of fluid.
- The clean oil, free of any impurities, exits the oil treater to a sales oil tank.
We Have Highly Efficient Oil Treaters & Free Water Knockouts
At Aspire Energy Resources Inc., we offer professional vessel fabrication and repairs using high-quality materials that meet the required industry standards. We have experts to understand your requirements and offer fabrication or modification services accordingly. We also have a wide assortment of separators, including horizontal separators and oil treaters.
For more information about our products and services, give us a call at 403-314-5422 or 1-800-993-9958 or fill out our online form to request a quote.