Electrostatic Dehydrators

Crude oil generally contains gas, water and solid contaminants. Prior to downstream processing of crude oil into commercial petroleum products, these contaminants must be removed. Electrostatic dehydration, a principal technology offered by Mackenzie Hydrocarbons, is the standard process to meet this need.

Electrostatic Dehydration – General Principles

The components of the electrostatic treater are contained in a horizontal vessel. Inside the vessel, the oil and water feed is distributed symmetrically by inlet header. Stokes’ Law dictates that the heavier water phase will migrate towards the bottom of the vessel. After this initial separation which separates much of the oil from the water, the stream is directed to an electrostatic grid that applies an electric field of between 12,000 to 30,000 volts. The electric field breaks the oil/water emulsion, inducing most of the remaining water droplets entrained in the oil to coalesce. Water travels to the bottom of the vessel and is drawn off. If Gas is entrained with the crude oil feed stream it can be vented from the top of the vessel. A sludge removal system (usually referred to as mud or sand washing) is included in the bottom of the vessel to remove solid material such as sand and mud. And an emulsion header may be included so that heavy emulsions can be recycled if necessary. Usually demulsifier chemical is injected upstream of the electrostatic treater.

Continuous Design Evolution

Mackenzie Hydrocarbons has years of design experience in the design of dehydration by electrostatic dehydration. The company has specific experience in handling heavy crudes, waxy crudes, naphthenic crudes, and high BS&W streams. Recently the company has developed a new innovative electrostatic grid system – a combination of tubular and plate electrodes. This system offers improvement in the oil carry-under so it minimizes environmental water problems and saves loss of product. Internals include proprietary grid electrodes, secondary treating of effluent water, and “high intensity” plate electrodes.These electrodes are now in commercial production.In addition the company has introduced the concept of including oil-water separation internals in the water phase to further enhance the quality of effluent water.