How does an Air Compressor Oil-Water Separator Work?

There are several ways that you can separate oil from water vapor within compressed air systems. It’s important to separate the both as due to environmental considerations you can’t simply dump the two together out and into atmosphere, therefore oil separators are vital.

They work via a number of methods, depending on the type you buy they may use:

Gravity Separation

Chemical Absorption

Non-Chemical Absorption

Absordtion

Gravity Separation

The simplest method and therefore not the most effective. It involves letting the oil and water settle naturally. Due to oils being the less dense of the two, they will typically situate themselves at the top of the separator.

However, it is still possible for some of the oil vapor to become emulsified within the water during compression so gravity alone will not be able to separate these.

Chemical Absorption

A chemical media like activated carbon is used in this method to attract bonds with oil and repel the water. Oil reacts chemically with the activated carbon media, which enables the filter to trap the oil particles within itself, so that the water can be drained.

Non-Chemical Absorption

It’s possible to have a media made out of materials that attracts oil and repels water without the chemical bonding process previously described. An example would be polypropylene, this material is oil-absorbent and water-repelling.

Adsorption

Similar to absorption, but instead of focus on the core of the media, adsorption attracts the oil to the surface of the material. Adsorbent materials will have multiple tiny pores within them which help maximize the amount of oil it can adsorb by attracting it electrostatically.