The deposition of paraffin wax from crude oil at low temperature is one of the serious and long- standing problems that induce high viscosity and poor flowability which restrict the processing of crude oil and causes huge economic loss. Addition of pour point depressants (PPDs) has been proved to be an efficient way to inhibit wax deposition. In the present work, six green terpolymer pour point depressants comprised of [sunflower oil- octadecane- acrylic acid/vinyl acetate] at different molar ratio were prepared by a facile method. These are coded as SOA and SOV respectively. The chemical transformation of sun flower oil was proved by infrared (FTIR) spectroscopy and the molecular weights of the prepared PPDs were estimated via Gel permeation chromatography (GPC). In comparison to composition and operational parameters, the produced additives' effectiveness as pour point depressants for waxy crude was confirmed. Moreover, the surface tensions at dodecane versus different concentrations at 25oC were displayed in order to verify the surface activity of the green terpolymers.
The pour point measurements showed that pour point temperature of the examined waxy crude was acceptably reduced by the addition of any of the investigated surfactants. The amount of reduction was dependent on the variation of molar ratios comprising the terpolymer. The data revealed that the additive SOA1 [with equimolar amounts of constituents] displayed maximum reduction in the pour point of crude oil samples. The shear rate-shear stress and shear rate-apparent viscosity were measured at different temperatures below, higher and equal the pour point temperature. By applying the photomicrography examination, it was found that, the wax morphology was noticeably adapted into fine dispersed crystals.