Did you know that moisture is always present in the air, even when it's not visible? When air is compressed in a compressed air system and cooled past its dew point, the moisture condenses into liquid water. This poses a challenge since compressed air systems require dry air to function effectively. To prevent corrosion and ensure optimal performance, the air must be free of liquid moisture and maintain a relative humidity below 50%.
While filters and separators are able to remove 99% liquid moisture droplets from the air, this is only at the temperature of the air at the time. Hot air has smaller moisture droplets and so less can be removed compared to cooler air. In order remove more water vapor from the air, you must cool the air down to a lower temperature (e.g. under 5°c), and for this a refridgerated air dryer / chiller is needed.
SMC filters and separators are generally sufficient for air consumption for air tools such as blow guns or construction tools (chipping hammers) however if you really need dry air, for example for painting, a refridgerated air dryer / chiller is the way to go.