Emulsion Technology has now come to
pervade a wide range of industries and
emulsions are formulated to suit a
gamut of physical, chemical and biological
requirements.
Two very distinct classes of emulsions
exist: (a) macroemulsions (b)
microemulsions. The fundamental difference
between these two types of emulsions
is due to their relative stability
, toward phase separation and size of
the disperse phase droplets.
Microemulsions have received remarkable
attention in oil industry as the
means for developing a new recovery
process. The recovery process utilizes
the unique properties of microemulsions.
Micellar solutions satisfy requirements
for the slug of a miscible water flood
process. These solutions which displace
most of the oil in the reservoir, are
constituted of oil, water and surfactant.
They may also contain small amounts
of electrolytes and co - surfactants
such as alcohols.
The objectives of the present work
were :
1. To prepare different types of
microemulsions from crude column overheads
and crude oil.
2. To investigate the properties of
the microemulsions, mainly their viscosities
during phase inversion.
Transparent microemulsions were
made from hexadecane, kerosene and
white oil, using anionic and nonionic
surfactants, sodium and potasium oleate
and n-octyl alcohol. Two of the systems
were of o/w type miaroemulsions and
were formed with white oil and kerosene.
Chain length of the alcohol was controlling
factor in preparation of the
microemulsions. Alcohol chain should
be lengthened while an oil with longer
chain is used.
Both macro and microemulsions were
made with crude oil.
At 20 C most of the microemulsions
behaved Newtonian, while at higher
temperatures they tend to follow non-
Newtonian, fluids. Crude oil emulsions
were non-Newtonian at all of the tested
temperatures.
Microemulsions were very temperature
dependent and phase separation was observed
both at higher and lower temperature
than that they were made at. Only
system 5 tolerated these temperature
variations without revealing any phase
separation.
Viscosity of the microemulsion decreased with increase in temperature.
System 3 was an exception. The result might be attributed to the phase sepa- 1
ration of the system. Increase in water content of the
W/O microemulsions caused increase in the viscosity of the system. The maximum
viscosity was reached a t the point of the inversion of W/O emulsion into
o/w emulsion. For the microemulsion with white o i l , the Phase inversion occured
a t about 70 per cent water by volume, which was in close agreement with O s t -
wald's theory. In both systems fluids started to behave like Newtonian fluids.
Increase in water content was accompanied by non-Newtonian behaviors of the
system. Plots of shear stress versus shear rate for the systems showed that
the shapes of the curves changes around the inversion point.
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