Coalescer is a simple, virtually maintenance-free system for separating oil from oily water  utilizing a bed of oleophilic ion exchange resins. Coalescer can be used in petroleum refineries, petrochemical plants and related industries as well as treating ballast water, oil well field produced water and other oily waste waters.

The fill material is an oleophilic resin, which offers a good attrition resistance, allows the collecting of the microdrops of the oil emulsion in water and them salts out in the form of large easily decantable drops.

The mineralization of the purified water isn’t modified and can be recycling.

Before the treatment, the effluents must be filtered (TSS <5 ppm; < 125 µm. (

The objective is to coalesce the microdrops.

The resin picks up the microdrops from the oil emulsion and releases great drops of oil.

The mixture (water + oil) go up through a chimney. The oil is separated by gravity and float on the surface of the vessel where it accumulates.

On the top of the vessel, there are two phase :

an oil phase,

a purified aqueous phase.

A whole of measurements of pressure allows the control of pressure loss within the bed and detect any clogging. If the pressure increases inside the vessel and the flow rate decreases on each filter , we can expect that the filter is clogged.

The coalescer could be designed to operate automatically.



• Normal filtering rate:                   5-20 m/h         

• Operating temperature:              50-100°C                       

• Suspended solids:                         5 ppm    

• Hydrocarbon content, feed:       10-100 ppm  

 • Hydrocarbon content, outlet:    1 ppm