Chemical and Bio-Based Demulsifiers for Crude Oil-Water Emulsions: A Comprehensive Review of Mechanisms, Performance and Sustainable Solutions

Abstract

Crude oil-water emulsions pose significant challenges in the petroleum industry due to their stability, which is enhanced by natural surfactants like asphaltenes, resins, and waxes. Effective demulsification is essential to mitigate operational inefficiencies, corrosion, and increased viscosity. This review compares chemical and natural-based demulsifiers, evaluating their performance under laboratory and industrial conditions. Chemical demulsifiers, such as surfactants and polymers, are widely used for their efficiency and adaptability but raise environmental concerns. Natural demulsifiers derived from plant extracts, waste oils, and biopolymers offer sustainable alternatives, though their effectiveness varies with conditions. The study highlights the mechanisms of emulsion formation and stabilization, demulsification techniques (mechanical, chemical, thermal, and electrical), and factors influencing the process, such as temperature, droplet size, and interfacial films. While chemical demulsifiers remain dominant in industrial applications, natural alternatives show promise, particularly in eco-sensitive contexts. Future research should focus on optimizing natural demulsifiers and validating their scalability under industrial conditions.