Ig. Harpur et al., DESTABILIZATION OF WATER-IN-OIL EMULSIONS UNDER THE INFLUENCE OF AN AC ELECTRIC-FIELD - EXPERIMENTAL ASSESSMENT OF PERFORMANCE, Journal of electrostatics, 40-1, 1997, pp. 135-140
The destabilisation of water-in-oil emulsions is an important industri
al process and is often the rate-determining step in the dewatering an
d desalting of crude oils. In this study the influence of a 50Hz sinus
oidal electric field on flowing water-in-oil emulsions is reported. A
horizontal rectangular duct was used, with emulsion flowing through at
flow rates up to 100 litre/min, giving Reynolds numbers (Re) in the r
ange 1000 to 12,000. Electrocoalescer performance was assessed by meas
uring water droplet growth, using a specially developed technique with
a laser diffraction particle sizer. Under conditions of high water-cu
t, electrocoalescence can be so efficient that free-water drop-out may
occur, even in conditions of turbulent now. This can lead to the form
ation of a layer of water co-flowing with the depleted emulsion in the
duct. Study of the electrocoalescer behaviour under these conditions
has been carried out by image analysis using a Hamamatsu Image Process
or.