Deoiler is a chemical agent used to break the emulsion between oil and water. It is commonly applied in oilfield operations, including both oil wells and crude oil processing units. In the event of an oil spill at sea, deoilers are highly effective in separating oil from seawater, allowing for faster and more efficient cleanup of contaminated areas.

Deoiler Application in Oily Water Separation

An emulsion is a colloidal system consisting of two immiscible liquids. Emulsions are classified based on their dispersed phase. In oily water, the dispersed phase is oil, making it an oil-in-water emulsion.

As explained in our article Oily Water Treatment Using Oil Separator, emulsified oily water cannot be effectively treated using gravity separation alone, even with the aid of coalescing media. While gravity can technically separate emulsions, the settling time required is impractically long, making it an inefficient process. Therefore, alternative methods are necessary to effectively separate the oil phase.

Several approaches exist to break emulsions, including heating (as in heater treaters) and chemical injection using demulsifiers.

While heater treater systems have been covered in a previous article, this article focuses specifically on the use of deoilers.

In short, the application of a deoiler represents a chemical separation process, as the deoiler breaks the emulsion into two distinct phases: oil and water.

Deoilers function by reducing the interfacial tension between oil and water, allowing tiny oil or water droplets to coalesce into larger droplets. These larger droplets can then be more easily separated through downstream treatment processes.

Typical Base Chemicals Used in Deoiler Formulations:

• Acid catalysed phenol-formaldehyde resins
• Base catalysed phenol-formaldehyde resins
• Epoxy resins
• Polyethyleneimines
• Polyamines
• Di-epoxides
• Polyols
• Dendrimer