Dry Breathing Air

[chris8410]

Hello all,
I am writing to ask advice on some equipment I want to specify and later purchase. Any and all comments would be very much appreciated. I am an electric power engineer, so this project of mine is a bit out of my league.

I would like to have built for my company a portable air drying system. Specifically, an air compressor supplying an air dryer. The output needs to be very dry breathable air, with a dew point of less than -80F, a flow rate of about 24SCFM at a minimum pressure of 50psi. This air will be used for allowing my employees to breathe safely and at the same time maintain a very dry environment inside of a large work area (10,000 gallons enclosures).

Here are some questions:

1. Could you recommend a very good company for the air dryer itself? The mode of drying should be heatless, regenerative desiccant-type. I am looking for quality and reliability. Presently I am looking at the ZEKS Company.

2. In addition to the air compressor and air dryer, I am being advised by others that the air should be "scrubbed" so as to remove any CO, odors, oil mist from the compressor, etc. Can you provide a high quality vendor for these items? ZEKS provides air dryers with special filters, etc, for these pollutants. Example: ZEKS CDP034

Again, my goal is to buy high quality equipment that also may have minimal maintenance requirements.

Thanks in advance or any help you can provide.

Regards,
Chris

 

[Ashereng]

chris8410,

If what you need is breathable air, for human consumption, then I would probably purchase a air supply designed for human use.

If I need utility air, or instrument air, then an intrument air package, from one of many vendors, would suffice.

What I am saying is, I would buy 2 separate air packages, because the applications are very different.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[waross]

Let us know how your employees react to breathing bone dry air. No criticizing, just wondering.
Thanks.
respectfully

 

[Ashereng]

waross, isn't the air in a SCBA fairly dry? Not sure if it is bone dry though. Just a question.

"Do not worry about your problems with mathematics, I assure you mine are far greater."
Albert Einstein
Have you read FAQ731-376 to make the best use of Eng-Tips Forums?

 

[chris8410]

Waross,
The industry has been using air with very low dew point for over 50 years without any issues. The air is purchased from a bottled gas vendor, typical dew points are -80F or better....bone dry.

The goal of my attempt to buy an air dryer is to get away from the dependance of buying such air from a gas supplier. There appears to be many qualified vendors that make air dryers.

The air is used to provide a very dry enviroment inside of the tanks of large oil-filled high voltage power transformers (up to 1000MVA, 765kV). Common situations are assembly, repair and maintanance of transformers at customer sub stations and power plants. Low dew point implies the critical winding insulation will remain dry during our in-tank work (with oil removed).

Regards.

 

[budt]

You could use a high pressure compressor (10,000 PSI) with inter-coolers between the stages to cool the air and condense the vapor. After the vapor condenses, drain it and then when you release the air to a lower pressure the dewpoint will be very low.


Bud Trinkel CFPE
HYDRA-PNEU CONSULTING, INC.
fluidpower1 @ hotmail.com

http://www.fluidpower1.us

 

[waross]

chris8410
Sorry, I misunderstood your post. Have you looked at packaged air supplys for instrument air? Both cleanliness and dryness are important for instruments.

waross, isn't the air in a SCBA fairly dry? Not sure if it is bone dry though. Just a question.

Good point I withdraw my comment.
Your comment also relates to
budt's post which is very similar to the method used to charge SCBA tanks. A bit less pressure but you don't want any condensation running down the divers breathing hose when his tank is inverted.
I stand corrected.

 

[zeusfaber]

BA Air is very dry indeed - not only do you want the cylinders not to rot from the inside, but it would also be nice if you didn't get condensate freezing the innards of the valves. Not especially nice to breathe for a long time, but preferable to anything seasoned with oil mist.

Typical HPACs for BA charging have the multistage arrangement with interstage cyclone separators described by budt and waross - followed by a filter tower charged with (often among other things) silica gel and molecular seive.

The tower will remove moisture and oil mist. It's unusual to see one which takes CO out (though it can be done if you include a hopcalite layer)- managing the source of inlet air, and keeping the compressor reasonably well maintained normally provide adequate CO control on their own.

I haven't had cause to look for one in a long time, but you used to be able to get inline filters which would let you run an airline mask off an industrial airline in an emergency - if these are still available, they're probably the sort of technology you want to be thinking about (lower pressure, higher flow than an HPAC tower).

You might look to see what's available from BA manufacturers (try Scott International) or Compressor makers (Bauer?)

A.

 

[FieldTeam]

We use air supply systems in the aviation business for confined space entry manufactured by Rhine Air Inc. They claim to tailor to their customers needs. Maybe contacting their reps will get you an off the shelf unit.

http://www.rhineair.com