Nearly every oil and gas well generates water as part of the production process. This water has to be treated prior to discharge or reinjection.
This is what the Stauper Compact Flotation Unit does.

How we do it

The Stauper CFU is a vertical flotation vessel with high throughput in a small footprint.

The Stauper CFU removes oil, gas and solids from the produced water, has no moving parts, requires no external power and minimal maintenance.

The process

The Stauper CFU is a vertical vessel, that utilize proven and well-known gas flotation principle. The main vehicle for separation of the oil from water is gas. The CFU utilizes both external induced gas as well as the gas already dissolved in water to separate the oil from water.

The CFU generates small gas bubbles that are induced into the produced water in a dedicated inlet chamber, where the gas coalesce with the oil droplets. The gas bubbles carry the oil to the top where oil, gas and fine particles are removed before cleaned water is ejected from the vessel.

The Stauper CFU efficiency is due to its internal design, process and fluid mechanics.

Heavier solids are captured and flushed from the CFU as part of the process.

The Stauper CFU has no moving parts and is very stable and robust.

How we differ from competition

Earlier generations CFUs are typically designed with one open vessel design where mixing, flotation and separation are done in one open setting. In this old design, smaller oil droplets and solids particles will follow the gravity and stream of cleaned water impeding the efficiency. 

The Stauper CFU, on the other hand, has a unique, patented design and fluid mechanics that differentiate from these older technologies.

Utilizing a separate inlet chamber where oil and gas are mixed and solids captured, there is no counter-current movements allowing for smaller oil droplets and solids to follow the clean water outlet at the bottom of the tank.

Separation  takes place at the top of the vessel where water comes to a standstill, unlike open vessels where water is moving – often in a chaotic manner. 

Stauper CFU´s ability to capture and flush out solids will improve the cleaning efficiency and significantly reduce downstream wear and tear – for instance in reinjection pumps.

Our design allows for better efficiency, even with very small oil droplets, which in turn may reduce dependency of chemicals and reduced OpEx.


The Stauper CFU can be configured to handle a large span of flow volumes and oil in water content. The CFU is operating on a sequential cleaning principle, so with demanding flow composition, with very high oil in water content or very small oil droplets, additional cleaning stages may be required.

In these cases, the Stauper CFU can have multiple stages in one vessel.  The option of several stages in one vessel offers a very compact and light weight alternative to older designs depending on several vessels in series.

For high flow volumes, several vessels can be installed in parallel allowing for treatment of any flow rate and turn-down.

The Stauper CFU can be tied in at inlet separator, replacing hydro cyclones, polishing equipment and de-gassers in the produced water treatment process train.

Cleaned water can be reused, discharged or reinjected.

Stauper CFU 45 m3/hr, two stages
Stauper CFU 550 m³/hr, single stage
Stauper CFU 2x800 m3/hr serial and parallel operation
Stauper CFU, 380 m³/hr, two stages

Treats high Oil In Water content

Handles smaller oil droplets

Significant turn down – scalable

Proven in lab and offshore

Light weight & small footprint

Patented – unique design

Ideal for FPSO – unaffected by motion

Captures solids from water flow

Applications / Tie-Ins

The Stauper CFU is documented to provide a very efficient separation of oil, water, solids and gas.

The Stauper CFU can be tied-in at several points in the treatment process, offering efficient and cost-saving separation.

Offshore testing has shown:

  • Very high efficiency
  • Stauper CFU is flexible
  • Negligible effect of turndown
  • Negligible effect of Gas Water Ratio changes
  • Solids removal through the  process
  • Excellent stability

The Novel design of the Stauper CFU facilitates:

  • A single step technology
  • Replacement of several treatment stages in current processes (hydrocyclones and degassers)
  • Simplified operational processes as a result


Stauper´s patented separation internals can easily be installed into existing, or new oil-water separation vessels. This includes degassers, earlier design CFUs and Water Oil Separators (WOSEPs).  Upgrading these vessels with Stauper internals will allow for improved separation efficiency, handling of higher water cut and hand hence reduced oil in water discharge without costly new processing equipment.

Read more


Flow rate: 5 m3/hr and upwards
Operational / inlet pressure: 0.5 barg and upwards.
Pressure drop: Up to 1 bar each stage.
Sequential cleaning One to several stages in one vessel or single stage vessels in serial.
Reject rate: 0.5% – 1% of flow rate.
Retention time: <35 seconds each stage.
Temperature: Depending on operational pressure – typically from 10C and upwards
Standards: Standard-pressure vessel designs accommodate most pressures, temperatures, and design codes.
Materials: Accommodate customer requirements from low-temperature carbon steel to high-grade alloys.
Gas consumption: 5-10% gas volume at CFU operation pressure, depending on the amount of dissolved gas in the water.