The name is absent

Chapter 2

against coalescence with other droplets ^[21].

Methods to separate water-in-crude oil emulsions can be classified as
mechanical, electrical and chemical ^[29]. Mechanical methods focus on breaking
the physical barrier and/or on the difference in density between the aqueous and
oil phases to achieve separation. Electrical demulsification is based on the
application of an electric field to deform the droplets and generate a force of
attraction between drops, thus leading to coalescence. Chemical demulsification
refers to using chemicals to promote flocculation and/or modify the properties of
the interfacial films so as to cause coalescence.

For chemical demulsification, in order to demulsify the emulsion, the
requirements for the demulsifiers are ^[21]: 1) strong attraction to the oil∕water
interface with the ability to destabilize the protective film around the droplet and/
or to change the wettability of solids; 2) ability to flocculate the droplets; 3) ability
to promote coalescence by opening pathways for water’s natural attraction to
water; 4) promotion of film drainage and thinning of the inter-droplet lamella by
inducing the changes of the interfacial rheology such as decreased interfacial
tension and increased Compressibilityofthe interfacial film.

Each demulsifier plays a specific role in the demulsfication. Amphiphilic
molecules with molecular weight 3,000-10,000 Da, such as polyalkoxylated

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