The document summarizes techniques for pre-treating crude oil before refining, including desalting and desulphurization. Desalting uses processes like chemical desalting, electrical desalting, and filtration to reduce the salt content in crude oil. Desulphurization, or sweetening, removes sulfur compounds like hydrogen sulfide that can cause corrosion and pollution. Common techniques for desulphurization include hydrotreating, which uses catalysts at high pressure and temperature to convert organic sulfur in crude oil into hydrogen sulfide gas. Proper pre-treatment of crude oil through desalting and desulphurization is important to minimize problems in transportation and refining and produce cleaner fuels