Efficient Treatment of Desalting Oily Wastewater: An Innovative Solution Combining Coalescing Separation and CDFU Technology

Crude oil often contains salts (chlorides such as sodium chloride, magnesium chloride and calcium chloride) and water (dissolved or emulsified), and must be desalted by electrical desalting equipment before entering the distillation unit. The wastewater generated in this process is called desalting wastewater. It has a high oil content - the oil phase volume fraction can exceed 10% in severe cases - with fine oil droplets and a large amount of fine suspended solids. Its organic concentration is high, containing volatile phenols and petroleum substances, with salinity (measured as chloride ions) typically in the range of 2,000-5,000 mg/L. In recent years, as crude oil quality has become heavier and more inferior, the scale of water and agent injection has continued to expand to improve recovery and transportation efficiency, making the composition of desalting wastewater increasingly complex.

To address this challenge, Shenzhen SINOKLE Technology Co., Ltd. has launched a treatment solution integrating a coalescing separator with CDFU technology, specifically for desalting oily wastewater. Based on a purely physical separation principle, the technology operates stably and reliably with remarkable oil removal (over 95%). No chemicals are added; demulsification and oil removal are achieved physically, the recovered oil is of good quality and can be directly reused in refining, and no oily sludge is produced - relieving environmental pressure while creating economic value. In addition, the process flow is short, the equipment structure is compact, the footprint is small, and the unit is skid-mounted and highly automated, easy to operate and maintain, with a short construction and installation period. The system has strong shock resistance, runs smoothly and can adapt to large fluctuations in water quality.

Fig. SINOKLE process flow diagram for desalting oily wastewater treatment

Actual engineering case applications:

As verified by the actual operation of a petrochemical enterprise's desalting wastewater treatment project, this process can remove more than 95% of oil and suspended solids from refinery sour water. When influent oil does not exceed 100,000 mg/L and suspended solids do not exceed 2,000 mg/L, effluent oil and suspended solids remain below 150 mg/L.