COMPRESSED AIR DRYERS 2

[tomato5]

WHY IS A CONDITION OF PRESSURE DEWPOINT OF -40 F CONSIDERED BETTER THAN 30 F FOR AN INSTRUMENT AIR DRYER?

WHY CAN ONE TYPE OF DRYER MEET THE FIRST CONDITION AND A SECOND TYPE CANNOT?

THANK YOU

 

[MJCronin]

Tomato,

WHY, OH WHY DO YOU SCREAM ? TURN OFF THE CAPSLOCK KEY....

A pressure dewpoint of -40F is considered to be the ISO standard for instrument air. There are also particulate and oil maxima considered to be suitable for instrument air.

Not all compressed air systems are designed for the rigorous needs of instruments, therefore commercially available air dryers have been designed for these other systems.

Become familiar with the following standards:

ISO 8573.1 & ISO12500

http://www.airbestpractices.com/sys...t/n2/air-quality-standards-iso-85731-iso12500

Whatever you do, make sure that you do not thank any people that help you....

MJCronin
Sr. Process Engineer

 

[tomato5]

mr. cronin, i do not scream capital was not sent to create any consternation i apologize

thank you for the technical support

your last line is not understandable are you, in a roundabout way, asking to be thanked i would have thanked you in amy case you took the time and effort to respond

what is this about red flag is this from you or the owners of this site?

should not be edited or removed


thank you

 

[moltenmetal]

Dewpoint matters if you care about moisture in your lines or devices. If the ambient temperature in your distribution system can fall to 30 F or below, 30 F dewpoint isn't low enough.

Unless you need the air dry for process reasons (i.e. to feed an ozone generator or some other water-sensitive process), what you're trying to do is to have air that is "superheated", i.e. not saturated, in water vapour at the highest pressure and lowest temperature which will be encountered anywhere in your system- with some additional margin on that so that there is no risk of condensate formation. You can achieve that by two means: by compressing to a higher pressure, drying, and then throttling and reheating to ambient conditions at a lower pressure, or by doing a very scrupulous job of drying the air at your operating pressure. Both are big users of energy.

-40 F dewpoint is very dry air. It is beyond the needs of most instrumentation. And it can only be achieved by methods which waste a lot of energy to achieve this level of dryness.

Why is it harder, and why does it take more energy, to dry air very thoroughly than to dry it a little? I don't think you need to have that question answered for you!