US Patent 10260007 Desalter operation

Improved separation of oil and water as well as suspended solids from the emulsion layer formed in a petroleum desalter is achieved by injection of demulsifier into the desalter vessel to achieve a higher localized concentration of demulsifier in the emulsion layer so as to promote improved oil/water separation from the emulsion layer. The demulsifier may be injected into the water layer or the oil layer in the region of the emulsion layer or directly into the stabilized emulsion layer.