Induced-gas flotation unit
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].
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.