A study of the effects of phenolic de-emulsifier solutions in xylene on the de-emulsification of a Nigerian crude oil emulsion

The research and development of de-emulsifiers for separating water from crude oil emulsions usually result in varying degrees of success, depending on the location and the type of crude being treated. This makes de-emulsifiers crude oil specific and thus gives rise to the continuous search for more and effective de-emulsifiers that can meet the specific needs of each locality. In this study, base-catalyzed phenol formaldehyde resins were formulated at varying formaldehyde to phenol ratios (1.2:1-1.8:1); the assessment was carried out by the bottle test method at varied de-emulsifier concentrations (vol/vol) in xylene acting as solvent diluent. The bottle test was carried out at an optimum temperature of 70 °C, dosage of 50 ppm and residence times of 10 and 20 min. A factorial design was done to determine the best combination of the de-emulsification conditions for the resolution of the Nigerian crude oil emulsion. The results were analyzed and optimized using Minitab 16 utilizing a Pareto chart, normal effects, main effects and interaction plots. From the analysis carried out, it was found that the most effective formulated de-emulsifier was obtained at formaldehyde to phenol (F:P) mole ratio of 1.8:1, 80% de-emulsifier concentration in xylene and residence time of 20 min. This de-emulsifier obtained a water separation efficiency of 79% compared to the commercial de-emulsifier which gave 71% efficiency. Thus the solution of P:F de-emulsifiers in xylene enhances the de-emulsification of the Nigerian crude oil emulsions.