Abstract: With the deterioration of petroleum resources, the drainage quality from crude oil electric desalination unit is prominent. The atmospheric and vacuum distillation unit of a petrochemical company was taken as an example to study the influence of petroleum impurities on the quality of electric desalination drainage. Through the analysis of the causes of excessive drainage, it was determined that the main influencing factors were the increase of metal Fe ions, the content of mechanical impurities in the raw materials and the high water content of the raw material tank, and the secondary factors included the increase of the alkalinity of the water injection and the content of suspended solids. Through qualitative and quantitative analysis of the influence degree of various factors, and taking control measures such as preset boundary values, increasing the frequency of raw material analysis, and reducing the water content of raw materials, the electric desalination drainage of the unit can meet the requirements of the discharge standards. The research results provide a reference for optimizing the electric desalination process and improving the quality of drainage, which is of great significance for the green and sustainable development of the oil refining industry.

Key words: petroleum impurities, electric desalination, oil-water emulsions, boundary values