Overview – UNICEL Vertical IGF – Induced-Gas Flotation Unit
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Efficient oil/water separation for flow rates ≥160,000 bbl/d
For locations that require a compact vessel footprint, the UNICEL Vertical IGF induced-gas flotation unit is a simple, hydraulically operated gas flotation machine that delivers efficient oil/water separation with complete process containment.
The UNICEL Vertical IGF induced-gas flotation unit introduces air or gas into the wastewater inlet stream at the bottom of the vessel through an eductor, releasing the gas-water mixture in the separation vessel.
The floated oil and solids are skimmed from the surface of the vessel and the clarified effluent is discharged from the bottom of the vessel.
During design, consideration was given to reducing maintenance and operating costs. This resulted in a streamlined mechanical design with an externally mounted eductor. These elements yield lower capex and reduced operating costs while providing separation efficiency of up to 98% and a wide flow rate capability. Individual units can support flow rates from 1,000 bbl/d to more than 160,000 bbl/d [160 m3/d to more than 25,400 m3/d].
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Effective separation in a small footprint for constrained spaces
The process begins by providing pressurized water to a venturi-type eductor that creates a vacuum at the gas suction port, where the gas is introduced into the waterstream. The mixture is combined with the incoming produced water stream and then passes through a dispersing mechanism where small gas bubbles are formed. The bubbles interact with the oil and solids particles present. This stream passes through a baffle section within the separator vessel central riser at a reduced velocity, allowing the gas and oil and solids particles to flocculate prior to being released at the surface of the vessel.
The oil is periodically skimmed from the vessel into a skim trough by raising the operating level to a point just above the skim trough. As the liquid level rises, it spills over into the oil trough. When the skim cycle is complete, the level set point is reset, and the unit automatically returns to normal operation.
The intermittent skimming cycle reduces the oil skim rate to approximately 1% of the average daily flow.
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Special Features :
- Compact, lightweight vertical installation
- Low-maintenance design free of internal moving parts
- Minimal power requirements
Application of UNICEL Vertical IGF – Induced-Gas Flotation Unit
Streamlined for simple, efficient operation and maintenance, each WEMCO ISF system consists of a cylindrical vessel partitioned into several major components—floating, degassing, optional skim storage compartments, a recirculation pump and piping, and a liquid level control system. All equipment is skid mounted for rapid installation and startup. The WEMCO ISF system is an induced gas flotation system through which a high-velocity stream of recycled clarified water enters the cells containing influent water through eductor nozzles in the bottom of the vessel. This induces a recirculating flow of air or gas from the vessel freeboard into the process water, and a unique eductor arrangement uniformly distributes small gas bubbles throughout the cell volume. These bubbles lift contaminants to the liquid surface, forming a froth layer that is then skimmed from the liquid surface by a simple collection trough. Gas and a small volume of treated water are continuously recycled from the degassing chamber into the treatment cells. The skim cycles are automatically initiated by a timer. The cycle interval, duration, and level setpoints are all user selectable and can be changed without interrupting operation or entering the vessel. The power requirements of the WEMCO ISF system are very low; a simple recirculating pump provides gas induction and mixing in the flotation cells
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