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taki123
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1. 100kg of methane is compressed from 0.5MPa and 300K to 3.0Mpa and 500K in a closed chamber by a compressor. The compression process is assumed to be adiabatic, calculate the efficiency of this compressor. Specific heat capacity of methane under constant pressure is 35.58 kJ/k.mol.K and ideal gas constant is 8.314 kJ/k.mol.K.
I have managed to work out the work done by the compressor, and 2 volumes but am not sure how to use them to get the efficiency of the compressor. I believe it has something to do with carnots cycle, but I am not exactly sure. Any help would be much appreciated.
2. PV=nRT
W=Q+dU
Carnot efficiency
n=m/Mr
3. W=-nCvdT
R=Cp-Cv
So:Cv=35.58-8.314= 27.27
n= 100/16 = 6.25 moles
Therefore: W=-6.25 x 27.27 x (500-300) = -34087.5 kJ
PV=nRT
V1= (6.25 x 8.314 x 300)/(0.5 x 106)= 0.031 m3
V2= (6.25 x 8.314 x 500)/(3.0 x 106)= 8.67x10-3 m3
Any help would be much appreciated.
Thanks
Taki123
I have managed to work out the work done by the compressor, and 2 volumes but am not sure how to use them to get the efficiency of the compressor. I believe it has something to do with carnots cycle, but I am not exactly sure. Any help would be much appreciated.
2. PV=nRT
W=Q+dU
Carnot efficiency
n=m/Mr
3. W=-nCvdT
R=Cp-Cv
So:Cv=35.58-8.314= 27.27
n= 100/16 = 6.25 moles
Therefore: W=-6.25 x 27.27 x (500-300) = -34087.5 kJ
PV=nRT
V1= (6.25 x 8.314 x 300)/(0.5 x 106)= 0.031 m3
V2= (6.25 x 8.314 x 500)/(3.0 x 106)= 8.67x10-3 m3
Any help would be much appreciated.
Thanks
Taki123