Introduction
Compressed air drying is an industrial process that removes moisture from air by compressing it to a much lower pressure. This process is often used in compressed air systems to minimize the risk of moisture contamination. The process is based on the physical properties of gases and the way in which they interact with each other. Compressed air drying works by taking in ambient air, compressing it to a much lower pressure, cooling it to a much lower temperature and finally releasing it, removing moisture from the air in the process.
Overview
Compressed air drying is used to reduce the risk of moisture contamination in systems where air pressure is created from a compressor. Compressed air which is saturated with water vapor is pumped into a drying tower where it is cooled and desaturated before being released. The drying process is based on the physical properties of gases. The air is compressed in a compressor to a much lower pressure than ambient pressure, roughly double the system pressure. This causes the air to cool, as warmer air expands to a lower pressure and cooler air contracts to a higher pressure. As the temperature cools, the moisture present in the air condenses, forming droplets which can then be removed. The dryer is then filled with adsorbent material, such as silica gel which absorbs the water, removing it from the air. The air is then released and is ready for use in the system.
The Process
The first step in the process is to compress the air. Compressed air drying requires the air to be compressed to at least double the system pressure, although for some applications higher pressures may be necessary. The air is compressed by a compressor, which typically use either a reciprocating or a rotary compressor. Once the air is compressed, it is cooled and a desiccant is added to the air. Desiccants are usually silica gels, activated alumina, or zeolites which are added to the air to absorb moisture and prevent water condensation within the drying tower.
The next step is to cool the air. As the air is compressed, its temperature increases. In order to remove the condensate, the air must be cooled to a much lower temperature. This is done using a cooling system, typically either an evaporative cooling system, or an air-to-air heat exchanger.
The cooled air is then introduced into the drying tower. The drying tower is filled with an adsorbent which is used to remove moisture from the air. The most common adsorbent materials are silica gel, activated alumina, and zeolites. The adsorbent material works by adsorbing moisture onto its surface, forming a thin layer of water. The adsorbed water is then removed from the air as it passes through the drying tower.
Finally, the air is released from the drying tower. The air is now at a much lower humidity level than when it entered the system, and is ready for use in the compressed air system.
Conclusion
Compressed air drying is a process used to remove moisture from air which is created by a compressor. The process works by compressing the air to a much lower pressure than ambient pressure, cooling it, adding a desiccant, and then releasing it. The desiccant material absorbs the moisture present in the air, removing it from the system. The compressed air is now ready for use in the system and any risk of moisture contamination has been minimized.
