Viscosity reduction and stability study of Indian heavy crude oil/water emulsion using hydrogenated castor oil ethoxylate with 40 moles of ethylene oxide as surfactant

Viscosity reduces when heavy crude oil forms oil-in-water (o/w) emulsion in water or brine and can be easily transported through the pipeline. In this study, an oil/water (o/w) emulsion was prepared using crude oil and water as continuous and dispersed phases using two different non-ionic surfactants, hydrogenated castor oil ethoxylate with 40 mol of ethylene oxide, and castor oil ethoxylate with 40 mol of ethylene oxide. The advantage of using non-ionic surfactants is that they are biodegradable, are not affected by the salinity of water and their emulsion can be easily separated. An interaction plot and Box-Behnken Design (BBD) approach were used to optimize oil: water ratio, pH, and surfactant concentration to minimize the consumption of chemicals. O/W emulsions were characterized by optical microscopy, drop size distribution, and Attenuated total reflectance (ATR)-Fourier transform infrared spectroscopy (FTIR). A stability study was performed by gravity separation and turbiscan analysis. 2–10 v/v % toluene and n-heptane were mixed with crude oil for dilution, and viscosities were compared with the result obtained from the emulsification of crude oil using two different 1 v/v % non-ionic surfactants. Using COMSOL Multi-Physics software, a pressure drop calculation was performed, and a velocity profile was developed considering the transportation of crude oil as well as o/w emulsion (containing hydrogenated castor oil ethoxylate with 40 mol of ethylene oxide as surfactant) through the pipeline. • Viscosity reduction and stability study of Indian heavy crude oil/water emulsion was investigated. • Hydrogenated castor oil ethoxylate with 40 mol of ethylene oxide as surfactant was used. • Box-Behnken design approach was used. • O/W emulsions characterized by optical microscopy, drop size distribution and ATR-FTIR. • Pressure drop calculation was performed using COMSOL Multi-Physics software.