Methane is compressed in two-stage, double-acting compressor which is electrically driven at 165 rpm. The low pressure cylinder (30.5 x 35.5 cm) receives 6.86 cu m per minute of air at 96.53 kPa, 43.30C, and the high pressure cylinder (20.3 x 35.5 cm) discharges the methane  at 717.06 kPa. The isothermal overall efficiency is 74%. Find n and the kW output of the motor.

1. Steam is compressed from 10 bar and 673 K to an exit temperature of 873 K. If the isentropic efficiency is 75%, calculate the power requirements to compress 25,000 kg/h. Estimate the exit gas pressure. [12] 2. A 3000kW compressor is used to compress steam to the exit temperature and pressure of and 10 bar, respectively. Calculate the initial temperature and pressure of the steam, flowrate is 15 000kg/h and the isentropic efficiency of the compressor is 80% [13]