Evaluation of Ionic Surfactants Derived From Fatty Acids as Demulsifiers of Water‐In‐Oil Emulsions for Heavy Crude Oil Refining

ABSTRACT The effective separation of water from crude oil is essential for maintaining oil quality, maximizing production performance, and mitigating operational issues within petroleum processes. In this work, four ionic surfactants were synthesized and evaluated as demulsifiers of a water‐in‐oil (W/O) emulsion obtained from a sample of Mexican heavy crude oil to study the effect of the anion chain length derived from naturally abundant saturated fatty acids. Bottle tests, centrifuge tests, and microwave irradiation tests were conducted to track the kinetics of demulsification using the synthesized surfactants. The centrifuge and microwave tests significantly reduced the emulsion breaking time compared to the traditional bottle test, achieving more than 91% water removal. The ionic surfactant tetrabutylammonium stearate showed the best performance as a demulsifier. Factors influencing the emulsion‐breaking process were discussed, including the carboxylate anion chain length, demulsifier concentration, heating time, and the physical method used to enhance demulsifier performance (conventional heating, dielectric heating, and centrifugation).