Demulsification


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demulsification

[də‚məl·sə·fə′kā·shən]
(chemical engineering)
Prevention or breaking of liquid-liquid emulsions by chemical, mechanical or electrical demulsifiers.

Demulsification

 

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.

REFERENCES

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 ?
Zhao, "Demulsification process of asphalt emulsion in fresh cement-asphalt emulsion paste," Materials and Structures, vol.
The superiority of nano-HMX fabricated by mechanical demulsification shearing (MDS) technology was demonstrated, namely, green preparation, spherical shape, and high-quality properties.
Hartland, "Dynamics of Emulsification and Demulsification of Water in Crude Oil Emulsions," Industrial and Engineering Chemistry Research 33, 1271-1279 (1994).
Ultrasonic demulsification technique mainly uses the agglomeration effect and the viscosity reducing effect of ultrasonic wave on crude oil to make water droplets in the crude oil gather and accelerate oil and water two-phase separation [21, 22].
Either micellar copolymerization or reverse microemulsion copolymerization requires many procedures, e.g., demulsification, lavation, and drying to get the final product, so the cost of production is comparatively high.
Our products also include fluid performance additives for various oilfield applications such as foam control, demulsification, and formation fines control.
Food processing machinery, which faces the constant challenge of excess moisture, will benefit from a new high performance demulsification oil developed by lubrication specialist ROCOL.
The full effect cannot be obtained even using electrical demulsification. The concentration of alkali should be increased and the dosage of the alkali reduced to liquidate the unstable composition testified in Table 4.
Compared to mineral oils, the Renolin Unisyn OL range foams less, offers better demulsification and has superior air release properties.
They include chemical demulsification, thermal dewatering, centrifugation, screening, filtering, vacuum processing etc.
The strength of CA mortar comes from the hydration of cement and demulsification of asphalt emulsion, and the skeleton structure of CA mortar is formed by the asphalt being coated with hydration product of cement and sand [14].