Untreated compressed air contains moisture and gaseous and solid impurities that can pose a significant risk to your air system. Moisture, specifically, can cause your industrial air compressor piping system to rust, which will then interfere with your instrument readings and interrupt production processes. It is therefore vital that you remove water vapour from your compressed air using the right equipment.
Here are the four major types of compressed air dryers that you can use for your system.
Refrigerated Air Dryer
This is the most commonly used dryer in manufacturing plants and automotive repair facilities. It cools the air and condenses water vapour. However, it cannot produce air with dew points lower than freezing, only of up to about 2 degrees Celsius, so the air still contains some vapour. A refrigerated air dryer is ideal for applications that are not water-sensitive.
This type of dryer passes air over two beds of desiccant materials that absorb moisture. When the first bed’s capacity is saturated, air flows through the second bed while the first bed regenerates. A desiccant dryer produces air consistently below dew points, usually at -40 degree Celsius. It is best suited for protecting lab equipment, water-sensitive process supplies and control and instrumentation systems.
Chemical Air Dryer
A chemical dryer passes compressed air over chemicals, usually lithium chloride and calcium chloride, which trap moisture. The lowest dew point that can be achieved is 15 degrees Celsius. Installing coalescing filters upstream is essential to prevent liquid water from entering the dryer as this reduces the chemicals’ life. Particle removal filters downstream trap chemical residues.
A membrane dryer has individual membrane micro tubes that trap moisture. It needs minimal maintaining and is perfect for sub-freezing and explosive environments and remote areas.
You need to understand the particular uses of different compressed air dryers to ensure that you pick the right one for your air system.