Question

Propylene b compressed adiabatically from 113 bar and 30oC to I8 bar at the rate of 1 kg mol s-l. If the compressor efficiency is 0.8, what is the power requirement of the compressor and what is the discharge temperature of the propylene?

Answer 1

Propylene:

Tc := 365.6∙K

Pc := 46.65∙bar

ω := 0.140

T0 := 303.15∙K

P0 := 11.5∙bar P := 18∙bar

 

For the heat capacity of propylene:

A : = 1.637

 

 

Use generalized second-virial correlation:

The entropy change is given by Eq. (6.92) combined with Eq. (5.15) with D = 0:

τ := 1.1 (guess)

 

Given

 

The enthalpy change for the final T is given by Eq. (6.91), with HRB for this T:

 

 

The actual enthalpy change from Eq. (7.17):

 

 

 

Given

The actual final temperature is now found from Eq. (6.91) combined with Eq (4.7), written:

τ := 1.1 (guess)