What Are Desiccant Dryers?
What Are Desiccant Dryers?
A desiccant dryer is a device used to dry compressed air that contains excess moisture. Moisture in compressed air can cause corrosion, mould and other maintenance issues with industrial machinery.
A desiccant dryer uses a special adsorbent material with hygroscopic properties to pull and hold water molecules within itself. The material must be regenerated to regain its drying capacity.
Heated Blower Purge Dryers
Desiccant dryers are a popular solution to reducing compressed air dew points in the range of -40°F (-45°C). Without proper desiccant drying, moisture can cause high maintenance costs, end-product rejection, increased leakage, disturbances in instrumentation and control systems and shortening the life of pipework due to corrosion.
Regenerative-desiccant dryers are a common choice for compressed air users in the pharmaceutical, chemical and food and beverage industries. They use a porous desiccant that adsorbs water by collecting it in its myriad pores.
Refrigerated Dryers are among the most common types of dryers on the market. They cool the compressed air by using compressor coils filled with refrigerant to chill it down to 33deg to 40degF, condensing moisture in the air and letting the liquid water drain away.
These dryers can also be cycling or non-cycling, and come in a variety of sizes. Non-cycling units are usually more cost-effective and can be used in applications where the compressed air supply needs are not constant, such as in a small business.
Desiccant dryers lower the dew point of compressed air by adsorbing water vapor from the air and reducing it to a level below the freezing point. This reduces the risk of contamination, process disruption and physical erosion of your compressed air system by eliminating the ice crystals that form on equipment and processes when they are exposed to moisture-laden air.
Regenerative dryers can be designed and manufactured to meet very stringent service conditions. These can include very small air flow rates, low inlet temperatures and very low outlet dew points.
Activated Carbon Dryers
Activated carbon dryers are desiccant dryers which use activated carbon to remove oil vapor from compressed air. They are often used in the food, petrochemical, synthetic fibre, printing, rubber, adhesives, solvent manufacture, and coating industries.
Using a carbon bed to remove oil vapor from compressed air is one of the most effective methods available. However, since activated carbon is a sponge-like material that absorbs moisture not only on its surface but also in the core of its granules, it is necessary to make sure that the carbon is completely dry when it is placed into an air-drying system.