Abstract: To effectively solve the demulsification problem during heavy and high acidic crude oil desalting process, some of the universal demulsifiers with good performance were selected based on the crude oil properties firstly. Then the selected demulsifiers one by one mixed with different additives to test its dehydrating performance. Among of them, two kinds of demulsifiers with the best dehydration were selected. Finally, a good oil soluble demulsifier FO6 was obtained by comparing desalting effect, dosage and cost. The FO6 was then applied in a dynamic desalting experiment and industrial trial. The results indicate that when the dosage of demulsifier FO6 is 10 μg/g, the salt and water in crude after desalting is less than 3 mg/L and 0.3%, respectively. The oil content in electric desalting discharge sewage is lower than 150 mg/L, The process indicators conform to the requirements of processing crude of refinery.

Key words: heavy and high acidic crude oil, demulsifier, formulation, electro-desalting