Destabilisation of Water-in-Crude Oil Emulsions by Silicone Copolymer Demulsifiers
Abstract
Asphaltene aggregates are known to form viscoelastic film preventing the
coalescence of droplets in
water-in-oil emulsions formed during crude oil exploitation. Since phase
separation is necessary for oil
refining process, demulsifying additives are used. It was found that
formulations based on polysiloxane
copolymers promote separation of water from crude oil even at very low
concentration (few tens of ppm).
Two alternative scenarios of emulsion destabilisation can be envisaged: (i)
dissolution of asphaltene
aggregates or (ii) displacement of the asphaltene network by adsorption of
the more surface active
copolymer into void sites at the oil/water interface. In order to reveal the
mechanism of destabilisation,
interactions between asphaltene aggregates and copolymer were explored. For
that purpose various
techniques have been employed: small angle X-ray scattering allowing the
determination of the influence
of copolymer on the size of asphaltene aggregate; capacity of copolymer to
displace asphaltene
aggregates initially adsorbed on silica particles (which simulate water
droplets); Atomic Force
Microscopy (AFM) was used to observe the influence of copolymer on the
interfacial structure of asphaltene films spread on water surface.
Domains
Physics [physics]
Origin : Publication funded by an institution
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