Demulsification is a method used to reduce or disrupt the water - crude oil emulsion
system without uttering the initial composition of the crude oil. This process is done by the
introduction of chemicals called demulsifiers, which break the emulsion into aqueous and
organic phases. In this study, the demulsifier formulated was the base-catalyzed phenolformaldehyde
resin known as the resoles, with the ratios of phenol to formaldehyde, varied
between 1.0:1.2 and 1.0:2.0. The different samples of resoles where then ethoxylated to make
them more hydrophilic using different weights (10, 15 & 20 g) of polyethylene glycol (PEG).
Screening of the ethoxylated demulsifiers was done using the established bottle test procedure,
at 70 °C, the concentration of 50 ppm, and 20 minutes of residence or separation time, in order
to select the most effective demulsifier, based on the amount of water removed from the
emulsion. The best chemical-demulsifier produced was the ethoxylated resole, which was then
blended with xylene at varying percentages (0, 20, 40, 50, and 80 % weight/weight) and was
further screened, using the bottle test method. From the analysis, it was obtained that the most
effective ethoxylate-xylene demulsifier blend was sample DR3, and made of formaldehyde to
phenol ratio of 1.8:1, 20 g of PEG 400 blended with 20 % xylene. The demulsifier gave a water
separation efficiency of 85.7 %, compared with the commercial demulsifier, which yielded
72.7 %. The result indicates the practical significance of solvent modified demulsifiers for
separating crude oil emulsions in the petroleum industries