Back to Basics: Regenerative Desiccant Dryers
Regenerative desiccant dryers are typically twin tower constructions, meaning one tower dries the compressed air while the other offline tower is regenerated. The regenerative process is controlled on a fixed time cycle, however it can be much more efficient to measure the outlet dew point from the desiccant dryer and regenerate only when needed.
Here’s a breakdown of the different types of regenerative desiccant dryers:
- Heatless-type dryers
These dryers are best suited for smaller air flow rates, high inlet temperatures and very low dew points. The regeneration process takes place with the help of expanded compressed air, or purge air, and requires approximately 15 to 20 percent of the dryer’s nominal capacity to regenerate the media bed.
- Heated purge regenerated dryers
These dryers heat up to the expanded purge air by means of an electric air heater. They use 25 percent less energy than heatless-type dryers while limiting the required purge flow to around 10 percent.
- Blower regenerated dryers
Ambient air is blown over an electric heater and brought into contact with the wet desiccant to regenerate it. With this type of dryer, compressed air isn’t used to regenerate the desiccant material, which helps lower the energy consumption to 40 percent less than heatless-type dryers.
Regenerative desiccant dryers can achieve very low dew points eliminating a potential freeze-up while maintaining moderate costs of operation. Learn more about the benefits of regenerative desiccant dryers when you contact Your Compressed Air Systems Expert.