Abstract: Crude oil desalting has great impact on the operation of atmospheric and vacuum distillation unit especially when the types of crude oil processed are changing frequently. In this paper the problems happened in the high velocity electrical desalting unit of the Refinery of SINOPEC Yanshan Company were analyzed, and factors affected crude oil desalting, such as crude oil heat exchange temperature, the amount of water injection and mixing strength were properly adjusted. After the optimization the qualified rate of crude oil desalting reached more than 90%, which ensured the downstream unit had a stable long-turn operation.

Key words: atmospheric and vacuum distillation unit, electrostatic desalting, technical transform