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Could anyone please tell me how to calculate dew point of instrument air with a pressure of 10 bar?
 
Answers
12/07/2010 A: keith bowers, B and B Consulting, kebowers47@gmail.com
One uses a 'Humidity Chart for The Air-Water System' such as that found of page 566 of 'Principles of Unit Operations, Foust Wensel, Clump, Maus, Anderson fourth printing, 1966 Library of Congress number 60-6454.
12/07/2010 A: Alan Goelzer, Jacobs Consultancy, alan.goelzer@jacobs.com
The dew point of instrument air after the compressor and after cooler + knock out and before the drier system will typically be the discharge temperature from the after cooler. The drier system should be capable of bringing the dew point down significantly below the coldest anticipated winter temperature for the refinery or plant.
If the vppm water vapour is known / measured in the drier air product, then vppm times 11 bara pressure indicates the vapour pressure of water. Then, tables of aqueous vapor pressure over ice and over sub-cooled water must be located to figure the dew point.