Flow improvement of heavy crude oil through pipelines using surfactant extracted from soapnuts

Abstract Sapindus mukorossi or soapnut is a natural alternative of chemical laundry detergents and cleaners. Considering its applicability in reducing surface tension and biodegradability, soapnuts were used as flow improver of heavy crude oil in this study and results were compared with a commercially available surfactant. Addition of soapnut reduces viscosity and yield stress of crude by 87% and 83% respectively at 30 °C which is helpful for economical transportation of the heavy crude. Interfacial tension is reduced immensely and complex, storage and loss moduli are decreased appreciably due to addition of Sapindus and Brij 30. Wax crystals in surfactant treated crude oil decreased in diameter as seen in particle size analysis (Dynamic Light Scattering) and their shapes became disoriented and dissimilar forbidding them to interlink with each other as evident from microscopic studies (Cross Polarised Microscope).