When the desalting efficiency in processing the high-sulfur crude deteriorated, the desalter drum should be revamped, the screening of demulsifiers strengthened and demetalizing agent injected to ensure that the salt in desalted oil was less than 3 mg/L.

The new protective measures are detailed such as extension of residenee time in desalting drum,application of new types of water-soluble and oil-soluble demulsifiers, replacement of ammonia with organie amine as neutralizer and upgrading of materials from'304'to'3t6L'for structured packing in the vacuum distillation tower.

Technological modification of electric desalting units of natural gas oil;

Industrial test of electric desalting via supersonic emulsion breaking

The hi-concentration mixing water is composed of alkaline dregs wastewater and electric desalting water in refinery plant, the COD content is bout 3 000 mg/L, the salinity is about 1 700 mg/L, the ammonia-nitrogen content is about 50 mg/L, volatile phenol content is about 70 mg/L, sulfide content is bout 70 mg/L and amount of mixing water is about 50 m3/h.

(2) Electrical desalting process and electrical desalting tank are innovated twice, and rat cage electrical desalting technology is used to reduce the .