Emulsification of heavy crude oil in water for pipeline transportation

The stability and viscosity of W/O emulsions and their application for heavy oil pipeline transportation were investigated using two Iranian crude oil samples. An Iranian heavy crude oil sample named West Paydar and a blend of diesel and bitumen were used to produce heavy crude oil emulsions in water. The diverse factors affecting the properties and stability of emulsions were investigated. There was a restricted limit of 60 vol.% for crude oil content in the emulsions, beyond that limit the emulsions were inverted to water-in-oil emulsions. Different crude oil-in-water emulsions were prepared through addition of Triton X-100 surfactant. According to performed investigations, emulsification reduces the viscosity of the crude oil samples. However the viscosity of the emulsions increased by increasing the oil content of the emulsion, surfactant concentration, speed and time of mixing, salt concentration, and pH of the aqueous phase, while temperature of homogenization process substantially reduced the viscosity of the prepared emulsion. The stability of crude oil-in-water emulsions decreased by increasing the oil content while increasing the surfactant concentration, time and speed of mixing, pH of the aqueous phase and temperature enhanced the emulsion stability. The stability of crude oil emulsions was also increased by increasing the salt concentration. The main applicable observation of this research is that heavy crude oil-in-water emulsions can be highly stabilized simply by increasing the pH of the aqueous phase to basic values. (C) 2010 Elsevier B.V. All rights reserved.