Simulation of reciprocating compressor - adiabatic or polytropic compr

[chemmobile]

Hi,
I'm young process engineer and I work for design office in gas industry. I use ChemCAD simulator. My problem: I want to simulate compressor for natural gas in ChemCAD. Program gives me two model to choose - adiabatic and polytropic compression. I'm creating now simualtion of underground gas storage facility and there is big difference in my calculation between
adiabatic and polytropic model (for actual power even more than 0.5 MW on every stage of compression). I ask you for advice what model is more realistic for reciprocating compressor.

 

[zdas04]

Positive displacement compressors (like recips and screws) closely match an adiabatic model. Dynamic compressors (like centrifugal or blowers) are closer to a polytropic model.

David