Induced Gas Flotation (IGF) Filter

Induced Gas floatation is one of the various technologies available for the removal of oily particles contained in produced water. The main purpose of the IGF unit is to separate free oil from water. In this equipment, fuel gas is induced in the oily water in the form of tiny bubbles which are generated from a pumping device. The tiny bubbles attach to suspended oil droplets causing them to float.

This unit is a dispersed gas and coalescing produced water clarifier. It operates by dispersing natural gas as fine bubbles into the produced water stream using a differential pressure induction system. Recirculation pumps pressurize the water manifold supplying the Venturi eductors. As the pressurized water flows through the Venturi eductors, gas is induced and mixed into the water. The water-gas mixture is ejected from the bottom of the Venturi eductors, producing small bubbles that rise through the effluent, stripping entrained oil. The gas-rich effluent then flows through coalescing screens, enhancing oil removal. The stripped oil rises to the surface as froth, which is propelled over the oil bucket-skimming weir by internal vessel hydraulics.

The unit includes two electric motor-driven produced water recirculation pumps, circulating flow based on the inflow rate. There are also two double diaphragm pumps for the recovered oil condensate, transporting it to the wet oil tank or heater treater. The system utilizes Venturi Eductor assemblies, which are accessible through the water manifold top. Each assembly consists of an upper and lower eductor tube, a Venturi nozzle, and a static mixer, all of which are easily removable.

Optional Coalescer Pack Equipped IGF

To aid the separation process the IGF is equipped with coalescer packs and diverter plates. Usually, IGF vessels are internally broken down into compartments with each compartments consisting of eductors, coalecser pack and diverter plate. The IGF is also equipped with a deflector plate and an oil bucket. See IGF internal layout drawing for further visual clarification.

1. Diverter Plates

These plates seperate the IGF compartments. Each separation compartment consists of a pair of eductors and a coalescer pack. The diverter plates not only separate the compartments but also allow the fluid to flow in a predetermined manner. This increases the retention time which aides the proper removal of the free oil particles.

2. Eductors

The eductors are static jet pumps which uses water as a motive force to induce gas bubbles into the oily water. The bubbles assist the oil particles to coalesce to form bigger particle which float to the surface to form an oil film.

3. Coalescer Pack

Each compartment has a coalescer pack to further assist the formation of larger oil particles. The pack achieves this by increasing the contact surface area of the fluid thus allowing more free oil particles to come together. There are several types of coalescer packs. The plate type is used for this project.

4. Deflector Plate

The deflector plate is installed in the vessel with an inclination to force the oil film into the oil bucket. Since oil will float on water restricting the oil film to a portion will create a thicker oil film which can be skimmed into the oil bucket.

WTPL’s designed and manufactured IGF units provide:

Customized and Standard Packages
Vertical and Horizontal Options
ASME coded vessels
Minimal or no moving parts

Optional coagulant chemical injection
Optional impeller or sparger design – Skid mounted packages
Can deliver as low as 10 ppm
Oil in water concentration