Desiccant dryers remove moisture from compressed air and gas using a bed of adsorbent material. While one bed dries the gas, a second bed is regenerated. What separates the main designs is how the regeneration is done, and that decides how much gas and energy the dryer uses.
Heatless Dryers
A heatless dryer regenerates the off-line bed with a portion of the already dried gas, expanded to low pressure and passed through the bed. It is simple and reliable, with few parts to maintain. The cost is the purge gas: a meaningful share of the dried gas is lost to regeneration.
Heat Regenerated Dryers
A heat regenerated dryer uses a heater, or a blower and heater, to regenerate the bed. Because heat does the work, much less dried gas is needed for purge. The price is more equipment and a higher purchase cost, which pays back where gas or compressed air is expensive.
Heat of Compression Dryers
These use the heat in the compressor discharge to regenerate the desiccant. They need little or no purge gas and almost no extra energy, but they depend on a compressor that gives a hot enough discharge, usually an oil-free machine.
Closed Circuit Zero Purge Dryers
These regenerate the bed in a closed loop, so no dried gas is lost. They are the most efficient on gas use and the most complex.
How to Choose
- Cheap gas and a small dryer favors a heatless design
- Expensive gas or large flows favor heat regenerated or zero purge designs
- A hot oil-free compressor discharge makes heat of compression attractive
- Check the required dew point, the inlet conditions and the available utilities
Power Energy supplies gas treatment systems including gas dryers, for plants in Saudi Arabia and the GCC. See also PSA, TSA and VTSA explained.
Talk to Power Energy
Send us the gas, flow, pressure and required outlet specification. Call or WhatsApp +966 56 278 9535 or email sales@powerenergy.com.co.