3 replies to this topic

[56200358]

Hello

i have afew questions about production of instrument air. pressure1==>9 bar

 

1- what type of heat exchanger generally is used for inter cooler and after cooler?(AEW or AES or ...?) in water cooled after cooler, air should be in tube?

2- In what circumstances do we use cenrifugal comressor for instrument air system?

[Art Montemayor]

My recommendations:

 

9 bargs of air pressure is considered a relatively low pressure level.  Depending on the piping, water condensate removal, and compressor arrangement it might be more economical and practical to use the shell side of intercoolers as the air side.

 

Why are you investigating internal floating head designs.  That is totally impractical, unneeded, a potential problem with internal gaskets, and not cost-effective.  It doesn't make any sense.  I would use a TEMA type BEM, pure and simple.

 

A centrifugal compressor for instrument air makes sense when the volume flow rate is relatively high and constant.  A 100 hp+ application might be worthwhile to look at.

[Bodhisatya]

Art Sir has given a perfect reply, I will just add on something

 

The general trend here in India is that customer asks for an integrated IA (Instrument Air)/PA (Plant Air) and IG (Inert Gas, namely Nitrogen) system.

 

This scheme asks for common air compressor station which distributes IA, PA from a common header while the rest goes to Air Separation units for Nitrogen generation.As this system deals with quite substantial amount of Air,use of Centrifugal compressor is prevalent.

 

Bodhisatya

[56200358]

Dear Art, 

 

Thank you for your recommendations. in the following links, the floating head is recommended for inter and after coolers:

http://local.alfalav...ers - 07.10.pdf

http://www.funke.de/...e_id=16&clang=1

in first link in page 1 saying air is inside the tubes.