Oleophilic resin coalescers are used for the removal of free oil from aqueous streams.
Unidro has a decades-long experience in supplying resin coalescers. We have developed a unique design based on the use of two different kinds of oleophilic media (“dual step” coalescer).
The most common application of this technology is the treatment of possible contaminated condensates in oil refineries.
Many among the most famous international oil companies have successfully installed Unidro coalescers all around the world.
In the resin coalescer the feed water flows up through a sandwich-packed layer of oleophilic resin. Due to the oleophilic properties of the filling media, dispersed oil droplets tend to adhere to the resin beads thus forming an oily film all around the bead. Once this film grows it is then released by the resin and dragged by the water flow through to a second oleophilic media section where the oil droplets aggregate to form even larger droplets.
At the outlet of the second oleophilic section the water is discharged from a conveniently located outlet nozzle. The oil rises to the top head of the vessel where it is automatically discharged (normally on time control).
Deoiling of contaminated condensate is the typical application of the resin coalescer. This is normally part of a complete treatment unit that includes a pre-filter which is installed upstream the coalescer and an activated carbon filter which is installed downstream.
Starting from an oil content of several tens of milligrams per liter (up to 100), a typical coalescer performance would reduce the oil concentration down to around 1 ppm. The downstream carbon filter provides final polishing to the condensate bringing the residual oil content to ppb levels. The key added-value of installing the coalescer is the life extension of the activated carbon media which is proportional to the oil content reduction.
As the coalescer is sensitive to the presence of solids, an upstream pre-filter is normally installed to protect the oleophilic resin from rust particles that are likely to be present in the condensate.