CDFU Cyclonic Dissolved-Air Flotation Technology: Solving Emulsified-Oil Challenges in Oily Wastewater via Multiple Physical Separation Mechanisms
In oily wastewater treatment, oil does not exist in a single form. For scenarios such as petroleum refining, oilfield produced water, tank-farm draw-off water, and heavy-fuel-oil depot wastewater, the wastewater often simultaneously contains floating oil, dispersed oil, emulsified oil, and oil adsorbed on the surface of suspended solids. Floating oil has a larger particle size and can be partially removed by gravity settling or oil separation; but dispersed oil and emulsified oil have small particle sizes and strong stability and combine more tightly with water, so traditional oil-separator tanks, settling tanks, or ordinary flotation often have unstable removal effects on them.
SINOKLE'sCDFU cyclonic dissolved-air flotation technology is precisely a strengthened separation technology formed to address the difficult separation of fine oil droplets, emulsified oil, and suspended solids in oily wastewater. It integrates cyclonic separation, dissolved-air flotation, micro-nano bubble capture, and coalescence into one, does not rely on a single separation mechanism, and improves oil-water separation efficiency through the synergy of multiple physical actions.
From the perspective of process mechanism,CDFU CDFU first uses the cyclonic flow field to achieve rapid separation of oil, water, and solid three phases. After the wastewater enters the equipment, a rotating flow is formed under the action of a specific structure. Due to the density difference between oil droplets, the aqueous phase, and solid particles, the oil droplets gradually migrate toward favorable separation positions under the action of centrifugal force, buoyancy, and flow shear. Compared with traditional static settling, the cyclonic flow field significantly shortens the oil-droplet migration path and increases the separation speed.
The second key role is dissolved-air flotation. The fine bubbles released by the system collide with and adhere to fine oil droplets and suspended particles in the water, reducing the apparent density of oil droplets and particles, making them easier to float and separate. For fine oil droplets, relying solely on gravity for upward flotation is very slow, but after bubble attachment their flotation capability is significantly enhanced, improving the capture efficiency for dispersed oil and emulsified oil.
The third role is coalescence enhancement. Fine oil droplets in the wastewater, under the action of cyclonic disturbance, bubble collision, and the equipment's internal structure, undergo collision, adhesion, coalescence, and growth. After the oil droplet size increases, the flotation speed accelerates and subsequent separation becomes easier. This process is of great significance for wastewater with a high degree of emulsification and small oil-droplet sizes.
Therefore,CDFU CDFU is not a simple upgrade of ordinary flotation equipment, but a compact separation device integrating 'cyclonic rapid separation + microbubble capture + coalescence demulsification'. Its technical value is reflected in three aspects: first, improving the removal capacity for fine oil droplets and emulsified oil; second, simultaneously reducing suspended-solids content; and third, improving the stability of downstream treatment systems through rapid front-end load reduction.
In a petrochemical electric-desalting and tank-farm black-water treatment project in Xinjiang, the wastewater is characterized by high oil content, large water-quality fluctuations, and complex oil forms. The project adopted 'high-efficiency coalescing deoiler + two-stage'CDFU CDFU' combined process, with a treatment capacity of 150 m3/h, influent oil content <=20000 ppm, treated effluent oil content <=150 ppm, and oil water content <=30%. This case shows thatCDFU CDFU, on the basis of front-end coalescing deoiling, can further strengthen the removal of fine oil droplets and emulsified oil, achieving stable oil reduction for high-oil refining wastewater.
In treating heavy-fuel-oil depot oily wastewater, the wastewater usually contains heavy oil, dispersed oil, and more suspended impurities, and the oil-water separation difficulty is higher than that of ordinary light-oil wastewater. The Bangladesh fuel-power-station project adopted 'two-stage'CDFU CDFU + KFM filter' process, with influent oil content <=2000 ppm, effluent oil content <=10 ppm, and a treatment capacity of 120 m3/d. This project demonstratesCDFU the applicability of multi-stage flotation combined with terminal filtration in heavy-fuel-oil depot wastewater treatment.
From the scope of application,CDFU CDFU can be widely used for petroleum-refining electric-desalting draw-off water, crude-oil tank-farm draw-off water, oil-depot oily wastewater, oilfield produced water, fracturing flowback fluid, and other oily and suspended-solid wastewaters. For water with high oil content, high emulsification, and high fluctuation,CDFU CDFU can serve as the front-end core oil-removal unit; for projects with higher effluent requirements, it can be combined with KFM filtration, KHC coalescing deoiling, orCDOF CDOF advanced-oxidation unit to form a more complete system solution.
Overall,CDFU CDFU cyclonic dissolved-air flotation technology does not solve the mere problem of 'floating-oil removal', but performs strengthened separation for the multi-form oil in complex oily wastewater. Through the synergistic action of cyclonic flow, flotation, micro-nano bubbles, and coalescence, this technology can achieve efficient oil and suspended-solids removal within a short retention time, creating more stable influent conditions for subsequent oxidation, filtration, biochemical, or reuse treatment.
