Compressor' capacity calculations 1

[joisy]

Hello,

someone can suggest to me where to read about calculations of capacity of existing 2-stage compressor unit; with given upstream & downstream pressure/temp. Better than it's given for example in GPSA.

Maybe someone can email me some article on this ?
Thanks to all in advance,
cheers

 

[TD2K]

Have you talked to any equipment vendors?

Is there anything in particular about the GPSA methodology you aren't clear on? I've found it reasonably clear. Unfortunately for centrifugal compressors, the calculations are interative for an existing machine when you want to change operating conditions because you have to find the inlet flow that produces the required head. With multiple stages, it just becomes worse.

PD compressors are easier as they move (pretty much) a constant suction volume. Work out the density and you know the new mass flow rate. For centrifugals, it's not that easy as you've found out.

 

[pmover]

check the gmrc web site - i've not investigated the article.

specifically:

http://www.gmrc.org/gmrc/techpaperspdf/2002/basics_of_compression.pdf

while i use a slightly different equation (thermodynamically sound) for capacity than listed in gpsa, the results are nearly similar.

for best results, contact the mfg. the good folks in mt. vernon will be glad to help you. you can even download there sizing program and use it for your needs. the help file system is quite good in explaining the theory and providing examples. i find it quite useful and so do the process engrs.

other mfg's have their sizing program available as well.

good luck!
-pmover

 

[joisy]

Thanks guys,

Unfortunately this is a centrifugal one. How can i find mt.vernon, - this is manufacturer's name, or commmunity or newsletters list?

thanks...

 

[pmover]

joisy,
the folks in mt. vernon (ariel) mfg reciprocating and rotary type compressors. sorry about any confusion.

question for you: 1) are there performance curve(s) for this particular unit in question? and 2) is there a flow measurement device in piping upstream or downsteam of compressor that quantifies/measures gas flow?

for flow measurement in a centrifugal compressor, i've always had flow measurement devices (i.e. orifice meter, annubar, venturi, etc.) installed to measure/quantify gas flow through the unit. computing head is straightforward; therefore, easy to plot on performance curve to determine operating point.

to imply gas flow based on inlet/outlet conditions and compressor rpm, one would need the mfg performance curve(s). i am not familiar with any calcs to determine flow based on inlet and outlet conditions. meanwhile, i will investigate the gpsa and offer further comment.
-pmover

 

[Samiran]

joisy,

GPSA derivation of polytropic head is probably not accurate. But suitable for most calcs.

SG

 

[patrickraj]

joisy

Did u try Compressor handbook by Lapina?

 

[joisy]

Thanks you very much, friends for your replies, but I'm already out of this problem. However this maybe useful either for me or for someone else...
cheers,
wish you a succesful year............

 

[dcasto]

Try this place. They manufacture reciprocating and screw compressors. You can download their software that will give you a good idea on what their units can do.

http://www.arielcorp.com/

Also, Cooper Energy has a similar program for their units.

http://www.cooperenergy.com