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compressor sizing

compressor sizing

compressor sizing

(OP)
how to determine high pressure (up to 5000 psi, compression ratio =3 psia)and high volumetric flow rate centrifugal compressor sizing correctly. including compressor area, maximum allowable flow rate, impeller size, tip speed, energy required, and number of stage, cost estimation. please help and thank you.                                 

                                   rengantingang

RE: compressor sizing

  rengantingang,

What flow rate do you require and what is the gas????

This looks like a reciprocating compressor application (piston or diapragm type) and not a centrifugal. With that said this will most likely be a 5 stage compressor if a piston type.

If you can advise of the gas and flow rate I may be able to help you along.


Regards,

Robin

RE: compressor sizing

(OP)
Dear Mr Robinchandy,

the flow rate is about 50000 cubic meter/hour, and the gas contain methane, ethane, and little bit impurities (H2S).
Thank you very much!

regards


rengantingang

RE: compressor sizing

Hi,
I do agree with Robin's that recip compressor seems a better fit with five stages of compression and the flow rate at 42.378MMCFD. What is your suction pressure and temperature and what percentage by weight/volume of H2S in the gas. Need to know the gas composition to come up with accurate performance sizings for recip compressors. Are you looking at gas injection application or other chemical process applications. Based on 3PSIG suction pressure to 5000PSIG discharge pressure, compressing 42.378MMSCFD of 0.65 gravity natural gas, the estimated power of compression using multiple recip compressors is 16,110BHP.If you are looking at turbine-centrifugal, it could be around 20,000BHP.
Regards
athan   

RE: compressor sizing

Athan,
I come up with the same power requirements.

All,
Has anyone had experience with a centrifugal and recip in series on a similar application? It would be interesting to see what the cost differential would be with a cent/recip versus all recip. I ask the question because it will take quite a few, and large, recip cylinders to handle this flow rate at the low pressures; meaning a whole lot of cost and moving parts.

Robin

RE: compressor sizing

rengantingang,

If:

I assume that your discharge pressure is 5000 psI
And that your suction pressure is is 1667 psI
And that you wish to compress 50,000 Normal cubic meters per hour (43 MMSCFD)
And assume that the gas is N2: 3%, H2S, 1%, Methane 87%, Ethane 4%, Propane 3%, Butane 2% (ie MW of 18.83)
And assume that the suction pressure is 40 C

Then the suction volumetric flow is ONLY 402 Am3/hr. Such a low suction flow is NOT suitable for centrifugal compressor. It is eminently suited for a recip.


If on the other hand your quoted 50,000 cubic meters per hour is AT suction conditions, then I advise you that such centrifugal compressors were not yet built for your service.


It is important that we engineers communicate in consistent units in a precise manner so that others can understand our questions better and respond quickly in a positive manner without wasting everyone’s time.




Regards,

Guru

If you do not have a rotating equipment engineer in your company, recruit one immediately. It saves your company a lot of money and embarrassment. Do not leave specialist tasks to amateurs (:

RE: compressor sizing

(OP)
thanks rotaryguru

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