From 15 Minutes to 90 Seconds: What the CFU Compact Flotation Unit Changes in Oily Water Duty

The CFU, or Compact Flotation Unit, is a compact dissolved air flotation unit and a patented technology of Shenzhen SINOKLE Technology Co., Ltd. It belongs to a newer generation of high-efficiency, compact, enclosed and pressurized dissolved air flotation equipment. Its central idea is to bring swirl flow into flotation, so that centrifugal force raises the collision probability between bubbles and oil droplets and accelerates the flotation itself. The result is faster and more complete oil removal, in a much smaller box.

Why Is It Faster?

Conventional flotation relies on bubbles to carry oil droplets upward on their own. Collision efficiency is limited by that geometry, so the water has to dwell in the tank for 15min or more - typically a 10-15 minute band - and the tank grows accordingly. The CFU system instead makes the wastewater rotate at high speed inside the unit. The centrifugal force generated by the swirl drives oil droplets and suspended solids toward the bubbles, greatly increasing the chance that they meet and speeding the flotation rate. That compresses the residence time to within <90s, while single-stage oil removal efficiency can still reach over 80%.

The Key Figures

• Maximum treatment capacity of approximately 500 m³/h.
• Single-stage oil removal efficiency above 80%, with suspended-solids removal rate above 70%.
• Inlet tolerance: oil content up to 1000 ppm and suspended solids up to 200 ppm.
• Applicable medium temperature <80°C.
• Gas medium can be air, argon, natural gas and similar, which lets the unit adapt to different site conditions.

Side by Side With Conventional Flotation

• Residence time: 10~15min conventionally against <90s for the CFU swirl flotation.
• Single-stage oil removal: 60%~80% conventional versus above 80% for the CFU.
• Single-stage suspended-solids removal: 50%~70% conventional versus above 70%.
• Removable particle size at above 80% efficiency: >10μm conventionally against >5μm.
• Footprint: large area and heavy weight conventionally; only a fraction of that here.
• Automation: manual or semi-automatic versus fully automatic.
• Sludge and oil discharge: mechanical conventionally, pressure discharge here.
• Safety and environment: atmospheric operation with a gas-leak risk conventionally; enclosed and pressurized here, which is inherently safer.

Eight Advantages in Practice

High oil removal efficiency - single stage above 80%, well beyond conventional equipment. Compact structure, with footprint reduced by 80%. Skid-mounted design, so the construction period is short and the unit is ready to use once installed. Stable performance with strong shock resistance, because there are no moving parts. Low operating cost, thanks to automated control and easy maintenance. Safe and environmentally friendly, since enclosed pressurized operation removes the gas-leak risk. A proprietary core patent. And fully automatic operation, which means efficient unattended running.

Two of those deserve emphasis: no moving parts, combined with pressure oil and sludge discharge, directly eliminates wear items such as traditional scum scrapers. That single design decision cuts the maintenance workload substantially over the life of the unit.

Where the Footprint Saving Comes From

It is fair to ask why the same duty can be done in a fraction of the space. The residence-time cut is most of the answer: if water needs well under two minutes inside the unit instead of a quarter of an hour, the tank volume that time implies simply is not needed. Pressurized enclosed operation then removes the open basins and their freeboard, and the absence of moving parts removes the walkways and maintenance access that scrapers and drives demand. What is left is a compact pressure-vessel package rather than a concrete structure.

A Case in Point

The Tuha Oilfield produced-water treatment project applied CFU swirl flotation technology to remove oil and suspended solids from oily wastewater efficiently, with effluent indicators better than the applicable discharge standards. In engineering terms, the enclosed pressurized operation is safe and environmentally friendly, the skid-mounted design makes installation straightforward, and fully automatic operation reduces O&M costs.

Where the Family Has Been Deployed

The SINOKLE swirl flotation technology family (the CDFU and CFU series) has been installed on projects worldwide: the Congo oilfield wastewater comprehensive treatment phase II at 250 m³/h (2026); the PetroChina Sichuan Petrochemical crude oil storage tank farm at 50 m³/h (2026); the Yunnan Petrochemical electric desalting drainage oil-removal skid at 105 m³/h (2025); the Urumqi Petrochemical electric desalting wastewater and tank-farm black water at 150 m³/h (2023); and the Bohai offshore platform produced water at 3 m³/h (2018). Those cover onshore oilfields, refineries and offshore platforms, with scales ranging from single digits to several hundred m³/h.

Who It Suits

The unit is aimed at oily wastewater treatment across petrochemical, refining and oilfield operations. It is especially suitable for space-constrained retrofit projects, skid-mounted installations that need rapid commissioning, and sites with high safety and automation requirements. When 90 seconds does what 15 minutes used to do, at a fraction of the footprint and with a safer operating envelope, the choice becomes fairly clear.

One qualification is worth stating, though. Swirl flotation earns its advantage on oily water with suspended solids; where the stream is essentially clean water with a trace of free oil, the extra machinery buys little. The technology is best judged against the duties it was built for, which is why the project list above reads as a set of oily-water problems rather than a general catalogue.