Removal of Acids from Sudanese Heavy Crude Oil by Polar Organic Solvents

Abstract

The aim of this study was to investigate the possibility of removing acids from Sudanese heavy crude oil which is characterized by acid number more than 7 mg KOH/g by liquid-liquid extraction technique. In this work polar organic solvents (methanol and ethanol) was used. The processes were applied at different temperatures and organic solvents volumes. The optimum solvent, solvent ratio and temperature were determined. The physical and chemical properties of crude oil sample were tested before and after extraction processes to determine the effect of extraction processes in chemical and physical properties of crude oil sample. The obtained results showed higher ratio of acids removal (31%,39% and 50%) when ethanol is used as solvent, while methanol gave less amount of removal in the same condition (24%,31% and 36%). The removal of acids was found to be increase with temperature and excess amount of solvent. The highest reduction was appeared when 20 ml of ethanol was added to 80 ml of crude oil at 50°C. The physical and chemical properties of sample after three extraction process were showed slightly decreases in pour point and API, while Gas Chromatography and Fourier Transform Infrared results showed no effects by extraction processes for crude oil sample