The principle of coalescence has different applications, and one of these is filtration. The natural tendency of oily droplets to aggregate due to coalescence makes this principle the most effective when building special coalescence filters to separate oily particles or substances that act like oils from the air flow. The air obtained after filtration through these high efficiency coalescence filters is pure, as per demonstrations, with an oil/impurity content of almost zero.
In a typical coalescence filter process, oily particles enter the filter suspended in the air flow. Then, they remain trapped in the internal surfaces of the filter, which are made with special construction details that cause the droplets to aggregate through coalescence. This aggregation creates larger, heavier drops that precipitate into a dedicated collection tank, which then makes them available for possible reuse. The air leaving the plant is highly purified.