Air Dryer Design 1

[sb00]

Hi,
where can I get information on how to design an air dryer for instrument air compressor?
Thanks,
-SB

 

[Harold53]

You should ask to your compressor supplier. Normally they make packages to supply instrument air. The only thing you need to clarify is the type of drying unit,bu again the best source of information is your compressor dealer.

 

[saxon]

sb00, It depends on the type of dryer you need to acheive the required dewpoint of the system. As for different types of dryers available those are; Deliquesent approx. +55 deg.F,
Refrigerent approx. +45 deg.F dewpoint, Dessicant approx. -100 deg.F (dewpoints listed are pressure dewpoint).

So you see, it's not just a simple answer for your question.

For a standard on Instrument Air see the following site:

http://www.isa.org

Find the following standard, ANSI/ISA 7.0.01 1996, "Quality Standard for Instrument Air"

This will allow you to determine what type of dryer you need, but why design one yourself, when you can buy one off the shelf.

Hope this helps.
saxon

 

[sb00]

Actually, I need to know details like:
1) Do we use multiple beds in the same dryer vessel or single beds are sufficient.
2) What type of support shoud I select for my packed beds- I will also need to re-generate it.
I just need general information regarding hte design. I f I am unable to complete calculations on my own, I will surely come back to you guys.
Thanks...

 

[SeanB]

I am also specifying an Air Dryer design at the moment. But I am just specifying the Rated Air Flow for the dryer and the dew point that I require. I will give this information to the dryer vendor and let him do the rest. You will also have to tell your vendor whether you want heated or heatless regeneration.

 

[TomOC]

You should be able to get some basic sizing information from adsorbent manufacturers such as Alcoa and UOP. Both of these companies are interested in selling their activated alumina for this application and normally give out this info for free. If you need lower dewpoints molecular sieves by UOP, ZEOCHEM etc could be used but heat would likely be required in the regeneration process.

Dryer manufacturers may not be quick to give up bed support details.

Sincerely,
Tom

 

[sb00]

thnx guys.....

 

[Aldream]

sb00:

ANSI/ISA-7.0.01-1996 (Quality Standard for Instrument Air)would be a good start.

Good luck

 

[Chuck56]

Two beds (one on adsorption, one on regeneration) will be sufficient and suitable for instrument air drying. There are a number of companies that specialize in building compressed air dryers. Compressor distributors often sell dryers as well, but do not typically design them themselves.

I would not expect you to specify bed support details to a dryer manufacturer. As TomOC mentioned, internal details are typically considered proprietary by dryer companies on standard air dryers (bottom line-you won't get a vessel fabrication drawing). Experienced dryer companies use various bed support methods.

Regeneration choices depend upon your circumstances and available utilities. Pressure swing (heatless) use ~15% of your dry air, but use no other utilities (~100 watts for the control panel). Various heated types use dry air, ambient air or recirculated air and can use electricity, steam or waste heat. Tradeoffs of capital,utilities and available purge gas will impact the decision.

CAGI (Compressed Air and Gas Institute) is the organization most dryer companies belong to...

Chuck