University of British Columbia CHBE 244 Assignment4 - Soln.

CHBE 244: Chemical and Biological Engineering
Thermodynamics I
Assignment 4 Solution: Thermodynamics of processes
Issued on Mar 4, 2016 (Fri); Due on Mar 21, 2016 (Mon)
Problems: (3 Questions in total - 100 marks)
Q1 Regenerative Rankine cycle - closed and open feedwater preheaters (40 marks)
[5.6] A regenerative Rankine cycle utilized the schematic of the figure below.
• Conditions: T1 = 450oC, P1 = 3 MPa, T2 = 250oC, P2 = 0.4 MPa, T3 = 150oC, P3 =
0.1 MPa, P4 = 0.01 MPa, T9 = 140oC, H9 = 592 kJ/kg, ηpump = 0.8
(a.) Determine the pressures for streams 5, 6, 8, 9, and 10 in MPa.
(b.) Determine _ m2=m_ 1.
(c.) Determine the enthalpies of streams 5 and 6 in kJ/kg.
(d.) Determine the efficiency of turbine stage I.
(e.) Determine the output of turbine stage III per kg of stream 4 if the turbine is 80%
efficient.