A lean natural gas is available at 18oC and 65 bars and must be compressed for economical pipeline transportation. The gas is first adiabatically compressed to 200 bars and then isobarically (i.e. at constant pressure) cooled to 25°C. The gas, which is essentially pure methane, enters the 0.3 m I.D. pipeline at a rate of 32 kg/s.
a) Calculate the density (kg/m3) and velocity (m/s) of the gas at the pipeline inlet using generalized compressibility charts.
b) Using the pressure-enthalpy diagram for methane, determine
i) the power that must be supplied to the compressor, and
ii) the temperature of the methane leaving the compressor.
The compressor is 80 percent efficient on an adiabatie reversible basis.
c) Using generalized departure functions, calculate the heat that must be removed from the gas after the compressor.