English abstract
Crude oil transport through pipelines has advantages in terms of safety,
efficiency, and low environmental impacts over the other methods of transporting oil.
However, transporting heavy crude oil from fields to refineries has been a challenge due
to high viscosity and high economical pumping coststhrough pipelines. Thisresearch was
carried out to use a biosurfactant (BS) as a viscosity reducer, instead of chemically
synthesized surfactants (CS) and other energy-intensive methods to improve the flow
properties of heavy crude oil through the transportation pipeline and to reduce the
pumping requirements via emulsification.
Karim heavy crude oil of 17.95° API gravity and viscosity of 6-12 Pa.s at the shear
rate 17-68 s-1 and 25 °C was used to investigate the percentage of viscosity reduction
(VR) after emulsification using the BS. Furthermore, the reduction in pumping pressure
to pump the crude oil after emulsification was tested through a pipe of 1 m in length and
a diameter of 0.50 inches at different flow rates. The BS showed promising emulsifying
activities, where the emulsified Karim oil using it provided a VR> 97 % at different
temperatures 10, 25, and 40 °C and oil content 95, 90, and 70 %. Additionally, heating of
Karim oil to 40 °C to reduce the viscosity of transported heavy oil gives VR= (74-83) %,
while emulsification gives VR>97% at the same temperature. Another strength point was
added to the BS side, where the emulsifying activity of it was compared to the chemical
surfactant (CS). The CS was used without dilution because it was insoluble in water or
brines, but BS was diluted in Karim brine with concentrations of (0.25, 0.75 and 1.25 %).
The comparison was made at the same conditions of 25°C temperature, 90% oil content,
and a shear rate of 0.034-17 s-1. Both, the diluted BS to 0.75 v/v % and the undiluted CS
provides VR of 91% at the mentioned range of shear rate even though the BS was diluted
while the CS was not diluted. Moreover, the emulsification of heavy crude oil using this
BS achieved a 33-36 % reduction in pumping pressure, which will aid in lowering the cost
of pumping requirements and make the process more efficient. Furthermore, the BS
exhibits many advantages over CS. The BSs are more efficient and functional, where their
Critical Micelle Concentration (CMC) is many times lower than CS. Most of BS can stand
at high ranges of temperature and pH values. BS is environmentally friendly and can be
easily degraded, has low toxicity, and can be produced from available raw material.
