5 replies to this topic

[asade abiodun]

Hi all,

I am sizing a compressor with suction of 150 psig and discharge of 2300 psig. The number of stages of compression is 3 stages.

Please, how can i determine the discharge pressure of the 1st and 2nd stage compressors.

Information is highly appreciated.

Thanks.

[Art Montemayor]

Asade:

For a multi-stage reciprocating compressor it may be shown that the total power is a minimum when the ratio of compression in each stage is the same and the total horsepower is equally divided between stages..

R = P₂ / P₁

Where,
R = ratio compression over the compressor
P₂ = Final absolute discharge pressure of the compressor, psia
P₁ = Initial absolute suction pressure of the compressor, psia

For the ratio of compression to be the same between the various stages, the following is derived:

R = (P₂ / P₁)^1/n

Where,
n = number of stages required.

Applying the above relationship, I obtain a compression ratio of 2.41325 between stages. Therefore,

Stage 1 discharge pressure = 397.4 psia
Stage 2 discharge pressure = 959.2 psia

I hope this helps.

[Profe]

Hi Asade Abiodun

About your question, I think that you must review Thermodynamics. but for increase your Knowledge, attached I send a subject about Compressors. Reveiew it Thoroughly an at page 17 an 18 you will get about Multistage compressors and Inter stage pressure.

[asade abiodun]

Art,

Thanks for the information.

Can the equation be used for multistage centrifugal compressors?

[Zauberberg]

Hello Asade,

Dresser-Rand has interesting compressor sizing software. It is free for download:
http://www.dresser-r...fc/download.asp

Best regards

[vicini]

Here is another free sizing program http://www.arielcorp.com/