A Coalescer is a technological device performing coalescence. They are primarily used to separate emulsions in to their components via various processes; operating in reverse to an emulsifier. Liquid-liquid coalecers are widely used in oil refining industry to remove contaminants like amine or caustic from intermediate products in oil refineries and also for dewatering final products like kerosene (jet fuel), LPG, gasoline and diesel to <15 ppmw free water in the hydrocarbon phase. These coalescers are often electrostatic type, in which an alternating electrical field encourages the water droplets to coalesce and settle by gravity.