Comparison of the performance of chemical demulsifiers in the separation of water emulsions in Iranian heavy crude oils

Generally, one of the problems in the production, extraction, transportation and refining of crude oil, is the formation of a stable emulsion of water in crude oil. Water emulsions contain a variety of salts and other impurities. These salts damage the equipment for crude oil processing and transportation. Therefore, after extracting crude oil from the well, it is sent to desalting unit. Desalting operation is carried out at different stages and in different ways. One of the most important desalting steps (especially for heavy crude oil) is the chemical demulsifier injection. The chemical demulsifier material is capable of bonding with water emulsions. These materials have both hydrophobic and hydrophilic properties and can eliminate the stable emulsion and thus the water is separated from the crude oil. In Iran, a wide range of types of crude oil are being processed. Therefore, different chemical demulsifiers are used for demulsification. In this study, the performance of several chemical demulsifiers has been compared.