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(chemical engineering)
Prevention or breaking of liquid-liquid emulsions by chemical, mechanical or electrical demulsifiers.



the reverse of emulsification; the destruction of emulsions, that is, of disperse systems comprising two immiscible liquids, one of which is uniformly distributed as fine drops in the other.

In demulsification the emulsion drops increase as a result of coalescence (fusion) during Brownian motion, sedimentation (precipitation), or mixing. Demulsification leads to the complete or partial separation into layers of the liquids forming the emulsion. It occurs when the action of the emulsion stabilizers (emulsifiers) ceases to be effective, that is, the protective coating that they form on the surfaces of drops is destroyed or loses the ability to prevent coalescence. In industry and the laboratory demulsification is effected mechanically (by centrifuging, filtering through porous materials, and stirring), by heating or freezing, by the action of an electric field, by salting out (adding electrolytes), and by adding special reagents-demulsifiers, which neutralize the action of emulsifiers by reacting with them chemically or expelling them from the surfaces of the emulsion drops. Usually demulsifiers are surface-active agents with greater surface activity than the emulsifier of the given emulsion but with less stabilizing capacity.

Demulsification is extensively used in dewatering and desalting crude petroleum, in many processes in chemical technology, in butter production, and in other processes.


Clayton, W. Emul’sii, ikh teoriia i tekhnicheskie primeneniia. Moscow, 1950. Page 603. (Translated from English.)
Levchenko, D. N., N. V. Bergshtein, A. D. Khudiakova, and N. M. Nikolaeva. Emul’sii nefti s vodoi i metody ikh razrusheniia. Moscow, 1967.
References in periodicals archive ?
Hartland, "Study of Demulsification of Water-in-Crude Oil Emulsion," Journal of Dispersion Science and Technology 14, 541-557 (1993).
Thompson, "Chemical Demulsification of Produced Crude Oil Emulsions," P.
Shetty, "Chemical Demulsification of Petroleum Emulsions Using Oil-Soluble Demulsifiers," Industrial and Engineering Chemistry Research 30, 367-375 (1991).
Killner, "Emulsions of Seawater in Admiralty Fuel Oil with Special Reference to their Demulsification," Journal of the Institute of Petroleum 34, 281 (1948).
Kushnick, "Effect of Demulsifiers on Interfacial Properties Governing Crude Oil Demulsification," American Chemical Society: Toronto (1988), Vol.
The Chemical Demulsification of Crude Oil Emulsion: Problem in a Niger Delta Oil Terminal," Erdohl, Kohle, Erdgas Petrochemie 41, 71-74 (1988).
Masliyah, "Characteriztaion and Demulsification of Solids-Stabilized Oil-in-Water Emulsions Part 1.
Rapid Demulse 220 is a food-grade demulsification oil which is ideally suited to applications such as water-cooled homogenisers where the rapid separation of water from the oil is vital.
Amongst those manufacturers who are set to benefit most from its excellent demulsification properties, even under high load and elevated temperature conditions, are dairies and soft drinks producers.
An oil collecting station with a demulsification facility exists on the property.