Demulsification of Crude Oil

Demulsifiers, or fluid separators, are a category of specialized chemical compounds used to demineralize liquids, such as, oil. They are also commonly employed in the refinement of crude oil, which is usually produced with large amounts of water and other fluids. These substances were first discovered in 1801 by J.C. Wheatley.

Today, emulsification has become an integral part of the refining process in the petroleum industry. Liquid petroleum (LPL) undergoes several complex and distinct stages during which it moves from liquid to semi-solid phase. Among these stages is the Dekker Emulsion, also known as "The Cold Emulsive". The process is usually completed in less than five minutes, using cold water. As oil passes through this emulsion it becomes heavier and the pressure changes, emitting high temperature steam. The steam is used to liberate different components of the oil.

In order to complete the cold phase of the emulsification process, various chemical agents and reagents are added to the crude at elevated temperatures. Commonly used agents in this case are calcium thioglycolate, calcium carbonate, calcium chloride, calcium phosphate, magnesium chloride, manganese oxide, boron carbonate, zinc oxide, and nickel silica. The crude is then forced through a sieve to recover the compound gas and liquid components. During this phase, the compound gases are separated from water by the pressure change and are collected. The collected oil components are then treated with various chemicals, one of which is referred to as the deodorizer. Demulsification of crude oil fields is considered as important by the oil companies as it provides significant cost savings and environmental advantages.

The technique is generally used for the separation of lighter hydrocarbons, lighter lubricants, as well as greener compounds. In the dry form, the emulsions formed are too small to be economically useful. To solve this problem, various techniques were developed to alter the emulsification to a viscosity that is greater than 100 at most. This enables the extraction of more oil from the same amount of dry material.

To complete this step in crude oil production, wet-crude handling facilities are employed. In these plants, low pressure steam is used to force the droplets into suspension, where they can easily be separated. This separation process also produces high quality droplets that are useful in various applications. For instance, most of the oil drops produced in wet-crude handling facilities are recovered for reuse whereas some are sent to petrochemical industry for further processing.

The final step in the separation of crude oils is to remove them from the reservoir. Depending on the nature of the crude oil, the methods for this step vary. In cases of heavy crude oils, high pressure can be used to remove them from the reservoir. In some cases, basic sediment and water are used instead of water and basic sediment to clean the reservoir completely. There are also instances where solvent extraction is used instead of basic extraction to remove the heavier oil components completely.