Application of High-Efficiency Coalescing Pressure Oil Separators in Petrochemical Oily Wastewater Projects
As an important fossil energy source, petroleum plays a major role in advancing human economic and social development. The world extracts and processes huge volumes of oil every year — in 2024 alone China's crude output reached 213 million tonnes. Extracting and refining crude generates large amounts of oily wastewater; it is estimated that every tonne of refined product corresponds to 0.5-1 t of oily wastewater.
Such oily wastewater has complex organic composition, high salt content and COD reaching thousands or even tens of thousands of ppm, making it hard to degrade and highly hazardous. If discharged untreated, the oil in it gathers and forms a dense oil film on the surface of natural water bodies, blocking gas mass transfer between atmosphere and water, causing dissolved oxygen to plummet and carbon dioxide to rise sharply, thus threatening aquatic life. Efficient treatment of petrochemical oily wastewater has therefore become a focus of attention.
Oily wastewater can be treated by physical, chemical and biological methods. Mainstream conventional physical technologies include gravity separation, centrifugation and adsorption.
Gravity separation requires relatively large separation equipment, resulting in a large footprint.
Centrifugal treatment of oily wastewater uses centrifugal force generated by high-speed rotation to accelerate oil-water separation, but energy consumption is high (maintaining high-speed rotation) and emulsified oil requires an additional demulsification step.
Adsorption is also a common oil-water separation approach, but it faces problems such as high treatment cost and low separation efficiency at high oil concentrations.
Chemical methods require large amounts of chemical reagents, entail high treatment costs and introduce new impurities, which is unfavourable for reuse of the treated water.
Biological methods cannot treat oily wastewater directly because microorganisms cannot tolerate high-salinity environments; some pretreatment is needed before biological treatment.
As pollution discharge standards tighten further, conventional technologies and equipment alone can no longer meet current requirements for oily wastewater treatment. To solve the technical difficulties of petrochemical oily wastewater treatment, SINOKLE has developed a high-efficiency coalescing pressure oil separator for petrochemical oily wastewater.
A coalescing pressure oil separator unit at a petrochemical plant
The high-efficiency coalescing pressure oil separator uses purely physical demulsification and deoiling technology, effectively separating emulsified oil and suspended solids from water through physical action while improving slop oil quality. No chemical agents are needed — environmentally friendly and economical — and it strongly supports subsequent resource recovery. The unit can be used alone to remove emulsified oil from wastewater in advance, or combined with other advanced proprietary SINOKLE technologies for advanced oily wastewater treatment.
Its advantages include:
1. Bidirectional flow design and CFD optimization: compact structure and small footprint (only 50% of conventional units);
2. High-efficiency coalescing internals: fine coalescing removal size and short retention time (30% of conventional separators), with high oil removal efficiency (over 90%);
3. Internals made of stainless steel or reinforced PP material: high strength and long service life;
4. Special structure and packing design: sand does not accumulate easily, so clogging is unlikely;
5. Fully enclosed automatic operation: smooth and completely reliable.
Internal packing of the high-efficiency coalescing pressure oil separator
Thanks to its significant advantages, the high-efficiency coalescing pressure oil separator is now widely used in petrochemical oily wastewater treatment, produced water treatment in onshore oilfields and offshore wells, various oily wastewater streams at power plants, oil depot oily wastewater (such as storage tank cut water) and other oily wastewater (steel mill cooling water, cleaning wastewater, etc.).
