Coalescers are some equipments or chemicals? If it is an equipment, where to get it from? How much efficient it will be in removing water from the oil existing in emulsified form?

Good starting point:

http://www.pall.com/datasheet_chemical_26663.asp

A coalescer is a filter that allows both water and oil to pass through but the water is slowed down by the fibers which collect the fine water droplets and allow then to combine (coalsece) into much larger droplets that will drop out of the oil stream. The bottom of the filter housing has an automatic water drain valve that opens periodicly to drain the water out. Coalescers are effective for removing entrained water but not very effective for removing emulsified water and do not remove any disolved water.

Thank you very much, Buck.What is the efficiency of free -water removal in such filters and how economical they are?