air compressor dryer newbie question 3

[tygerdawg]

(ALSO POSTED IN GAS COMPRESSION ENGRG)

In a typical mfg facility, what is the advantages / disadvantages of a refrigerated air dryer versus a dessicant air dryer? Why would I choose one over the other?

Thanks in advance...


TygerDawg

 

[Barry1961]

Unless you need very clean air the refrigerated dryer is usally what is used. If you need very clean air you would put a desiccant dryer after the refrigerated dryer.

Desiccant dryers have filters to remove more than just water, such as oil vapor. Desiccant dryers will get the air cleaner. If you are starting out with dirty wet air you are going to spend a lot of time and money changing filters if you put only a disiccant dryer in the line.

Refrigerated dryers don't get the air as clean but are very low maintenace.

Barry1961

 

[pmureiko]

Barry is correct about the differences in refrigerated and dessicant air dryers. Another is the dew point of the air. I don't know if there is a cost in operation since the refrigeration system uses a compressor.

A refrigerated dryer is limited to a dew point above 32 oF because it will stop working if it ices over. Dessicant driers do not have this limitation and can remove moisture to provide lower dew points such as -40 oF. The dew point needs to be lower than the coldest temperature the air will see to prevent condensation and equipment damage.

 

[quark]

I think I should clear few points to avoid any misunderstanding. First of all cleanliness of air is nothing to do with the type of dryer and with proper filters you can get the cleanest air possible. Moreover, traces of oil is detrimental to desiccant dryer where as refrigerated air dryer can tackle this quite easily. You must have a filter in the outlet of the desiccant dryer where as refrigerated air dryer may not require this.

Refrigerated air dryers can dry air to almost -25⁰C ADP (PDP of 3⁰C at 10 kg/cm²)but desiccant dryers can dry air better than refrigerated air dryers if the pressure of air is common.

Desiccant air dryer initial cost will be low but operational cost may be high because of regeneration. The size of the dryer, dewpoint, budget and availability of service are the factor you have to consider when selecting a dryer.

Regards,