Chapter 2
alkylphenolformaldehyde resins and complex block copolymers, are usually used
for the separation of a large fraction of the dispersed aqueous phase [2]. They are
often termed coalescers. These molecules penetrate the stabilizing film at the
water∕oil interfaces and modify its compressibility and rheological properties by
disrupting the tight conformation of adsorbed asphaltenes, which leads to
coalescence.
Molecules with molecular weight above 10,000 Da such as ethoxylated/
propoxylated amine polyols act as flocculators by adsorbing at the water∕oil
interfaces and interacting with molecules also adsorbed at the interfaces of
nearby drops [30]. These molecules are effective in removing remaining small
water drops and tight, fine emulsions once most of the dispersed phase has been
removed.
Low molecular weight compounds (typically below 3,000 Da), such as
common surfactants, exhibit high interfacial activity. Thus they can suppress
interfacial tension gradients that occur in deforming interfaces of approaching
drops that precedes film rupture and coalescence. They can alter the wettability
(from hydrophobic to hydrophilic) of solid particles that are often adsorbed at the
interface and that also contribute to the stability of the film.
Solvents are used as carriers of the active components. In the solvents the
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