Electric Desalting Wastewater Treatment Technology

Electric desalting wastewater refers to the oily and saline wastewater discharged after the crude oil enters the electric desalting unit for desalting and dehydration. Its pollution components are complex and have always been a difficult problem in the industry to handle.

High oil content: The content of petroleum substances in electric desalting wastewater is relatively high. In severe cases, the volume fraction of oil can reach more than 10% or even higher. These oil droplets have a small particle size and are severely emulsified, increasing the difficulty of separation.
Abundant suspended solids: The wastewater contains a large number of fine suspended solids. These suspended solids not only aggravate the emulsification degree of crude oil but also cause serious corrosion and blockage of equipment.
High salt content: The salt concentration (calculated as chloride ion) is generally 2000 - 5000mg/L, mainly including chlorides such as NaCl, MgCl₂, and CaCl₂.
High organic matter content: The wastewater contains organic substances such as volatile phenols and petroleum substances, which may cause harm to the environment and ecosystem.

Other pollutants: The wastewater may also contain hazardous gases such as sulfide, posing a threat to the health of factory employees and the surrounding environment.

Difficulty in oil-water separation: The oil droplets in electric desalting wastewater have a small particle size and are severely emulsified, making oil-water separation extremely difficult. Although the traditional gravity sedimentation treatment process is simple to operate, the treatment effect is unstable and it is difficult to meet the requirements of the effluent water quality.
High requirements for equipment impact resistance: The refining electric desalting wastewater has a large oil content and fluctuates violently, requiring extremely high impact resistance of the equipment. At the same time, the wastewater is highly corrosive, prone to scaling, and contains a large amount of sediment, requiring the equipment to have good anti-clogging and sediment removal capabilities.
Poor reliability of chemical demulsification: Severe emulsification is a key link in the treatment process of electric desalting wastewater. However, the reliability of chemical demulsification is poor and is not suitable for all situations. Although physical demulsification methods have become a core technical problem, the existing physical demulsification technologies still have certain limitations.

Strict environmental protection requirements: With the increasingly strict environmental protection regulations, the requirements for the effluent water quality after electric desalting wastewater treatment are also getting higher and higher. Traditional treatment methods are difficult to meet the requirements of the effluent water quality, and more efficient and environmentally friendly wastewater treatment technologies need to be developed.

In response to the difficulties in electric desalting wastewater treatment, Kelijia Technology has developed a combination process of a high-efficiency coalescing oil remover and CDFU swirl dissolved air flotation, which has achieved good application results.

High-efficiency coalescing oil remover: Adopting the coarsening principle, shallow pool principle, and CFD simulation tools to optimize the internal space and structure of the tank, realizing the rapid aggregation, coalescence, floating (or sinking), and separation of oil droplets or suspended solids in water.

CDFU swirl dissolved air flotation: Integrating swirl centrifugal separation technology, ultrafine bubble generation technology, and dissolved air flotation technology, through the organic combination of multiple technologies, realizing the efficient and rapid separation of oily substances, emulsified oil, and suspended solids in wastewater.

Process Flow Chart

Pure physical separation technology, stable and reliable with a high oil removal efficiency (up to more than 95%);
Oil removal by pure physical demulsification without chemical agents, with good quality of recovered oil that can be recycled, without generating oily sludge (hazardous waste), solving environmental protection problems and creating economic benefits at the same time;
Short process flow, compact equipment structure, and small floor area;
Skid-mounted, automated, simple in operation and maintenance, short construction period, and can be implemented online;
Strong impact resistance, stable operation, and can withstand large fluctuations in water quality.