Demulsification of a Nigerian crude emulsion using ethoxylated-resoles and their xylene modified blends

Abstract

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 phenol formaldehyde 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.