Coalescing filter

Coalescing filters are essential in gas and liquid processing across the (petro)chemical and oil & gas industries. They achieve efficient separation of liquid aerosols from gas streams. Strictly speaking, however, a coalescer is not a filter: it does not remove particles by blockage, but through physical separation based on droplet growth and gravity.

What does a coalescing filter do?

A coalescer works on the principle of coalescence: fine liquid droplets (< 0.3 micron) merge into larger droplets, which can then be separated easily. This process is essential in situations with limited residence time or where precise separation is critical — for example, compressor inlets, gas sweetening units, or downstream protection of membranes and catalysts.

Besides gas/liquid separation (L/G), coalescers are also used for liquid/liquid separation (L/L), for example in amine or glycol recovery, or in the deconditioning of process water.