Mechanically induced gas flotation unit for secondary recovery of oil and solids from produced water

WEMCO depurators and Silverband

Remove oil and solids from with high separation efficiency

WEMCO® DEPURATOR units use mechanically induced gas flotation (IGF) to remove oil and solids from produced water. After the produced water enters the DEPURATOR unit, motor-driven rotors induce a recirculating flow of air or blanket gas into the mixture. This disperses small bubbles throughout the tank volume, and oil droplets and solids are carried to the surface in a rising gas froth, where they are recovered by skimming.

Applications include onshore and offshore (fixed and floating) oil production, refinery and petrochemical wastewater, and metal casting and primary metal industry wastewater processing. Though the original IGF design is still the standard for many applications, the new pressurized version—available in two- to five-cell designs—provides a distinct advantage for the oil and gas industry. 

WEMCO depurator commissioning
The efficient four-cell DEPURATOR unit reduces chemical requirement compared with conventional designs, decreasing opex.
Individual units for flow rates of 270 to 28,160 m3/d [1,700 to 177,000 bbl/d]
Operating pressure from atmospheric to 1.05-kg/cm2 [15 psi] gauge pressure
Separation efficiency up to 98% or more

Maximize efficiency with froth flotation

All DEPURATOR units use the froth flotation process to remove oil and solids from produced water. The key component is the mechanical aeration assembly that constantly disperses gas bubbles into the produced water. The oil, solids, or both adhere to the bubbles and then rise with them to the surface of the cell, forming a froth. Because the contaminated water and the floating froth are constantly being subjected to reintroduced gas, it is impossible for the floating materials to settle into the now-cleaner water below.

Depending upon the type of DEPURATOR unit, the froth is removed either by mechanical or hydraulic skimmers. The water then moves into the next cell, where the process is repeated. In the final stage, the now-cleaned water goes through a degassing discharge chamber and exits the unit. Units can be configured with two to five cells to achieve application requirements.

WEMCO depurators installed
The DEPURATOR unit features a sled design that eases onshore transportation and installation in difficult-to-reach locations, lowering capex.