Water in Your Compressed Air Lines?

Moisture in air lines is a very common problem and can wreak havoc for expensive production equipment. Ambient air contains water in vapor form generally referred to as humidity. As ambient air is compressed to perform work the water vapor is condensed to form liquid water in the compressed air piping.
Moisture in air lines is typically removed by one of two common methods. One method being to cool the air which allows the excess moisture to condense and be removed mechanically using gravity. The second method is to use a media to absorb the moisture. This media is usually referred to as desiccant with the most popular being activated alumina. Both methods utilize compressed air dryers. The moisture level of the compressed air after entering a dryer is usually measured in terms of “pressure dew-point” or PDP.
There are various types and designs of refrigerated dryers which chill the air then use a moisture separator and automatic drain to remove the water from the compressed air. Refrigerated dryers cannot cool the air below 32 degrees F as freezing will occur. Typical PDP’s produced will be approximately 40 degrees F. Here are some characteristics to consider when evaluating a refrigerated dryer:

  • Cycling vs. Non-Cycling

  • Air-cooled vs. Water-cooled

  • Heat exchanger design

  • Materials of construction

  • Refrigerant type

  • Energy consumption

  • Voltage

  • Footprint

  • Piping arrangement

  • Moisture separator

  • Automatic drain

Desiccant (or regenerative type) air dryers offer even more levels of complexity. There are various styles and levels of quality to consider. Dryers using activated alumina to dry air commonly produce air at a PDP of -40 degrees F, and -100 degree F PDP possible with other drying media. Desiccant type dryers, depending on the design, require a slip stream of the systems compressed air for regeneration. Specific attention should be given to the compressed air requirement for the type of dryer being considered. The amount of compressed air required for regeneration is commonly known as the “purge rate”. The purge rate is determined by the capacity of the dryer NOT the size of the compressor. A compressed air professional should be consulted to explain the benefits and/or disadvantages of each type of dryer. Various designs for desiccant dryers include:

  • Heatless

  • Externally Heated- Exhaust Purge

  • Externally Heated- Blower Purge

  • Vacuum Purge

  • Heat of Compression

In summary, rest assured your system can produce clean dry air if the appropriate processes are applied. The dirtiest, most moisture laden air can be cleaned and dried to meet the needs of your production facility. Feel free to contact one of our trained professionals for free consultation.

Contact Information

Vice President (North Region): Steve Briscoe
Phone: 1-877-IACSERV X 5006 
Email: sbriscoe@iacserv.com

Vice President (South Region): David Swinney
Phone: 1-877-IACSERV X1018
Email: dswinney@iacserv.com