Multiple Heatless Dryers

Schematic of dryer setup

Schematic of dryer setup

I have a customer that has 3 rotary compressor(2 normally run at a time) that are all joined together and run to a wet tank. Then the piping runs to 3 Heatless desiccant dryers. My question is why have 3 dryers like this versus having one big one? Thanks

Comments for Multiple Heatless Dryers

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Jan 15, 2016
Multiple dryers
by: Anonymous

Those are good points. I was giving a good explanation from our senior tech that it's simply that if one compressor shuts down, then the dryer can be valved off to save air consumption. A single large dryer would consume more air than two compressors can supply.

A more efficient solution would be a dew point demand monitor that could watch the dew point and regenerate the towers only when needed. They are wasting a lot of energy/air when the air demand is low.

Jan 14, 2016
by: Doug in

What Bill said, and also possibly two or more were cheaper.

But mainly for redundancy. Assuming there are the proper valves, any compressor or dryer can be down for maintenance without killing the entire operation.

I know a tire shop that has three compressors - Usually only one is needed, but when they get busy, they need two for maximum work output. The third is spare and rotated into service from time to time.
(they don't use dryers)

Jan 14, 2016
Compressed air dryer installation
by: Bill

Not being privy to the original design requirements, I can only surmise.

If the dryers are single tank, then periodically the desiccant has to go through a drying cycle. If there was only one dryer, that would preclude drying the compressed air while the desiccant was being regenerated.

If there is a sensor at the dry air tank that monitors the water moisture level, and depending on that reading, shifts valves to route the compressed air through a second (or third) dryer, to effect the correct level of dryness, that may be why.

I think the desiccant regeneration will be the reason, though.

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