Question

1. (10 points) A combined gas turbine-vapor power plant has a net power output of 45 MW. Air enters the compressor of the gas turbine at 100 kPa, 300 K, and is compressed to 1200 kPa. The isentropic efficiency of the compressor is 84%. The condition at the inlet to the turbine is 1200 kPa, 1400 K. Air expands through the turbine, which has an isentropic efficiency of 88%, to a pressure of 100 kPa. The air then passes through the interconnecting heat-recovery steam generator and is finally discharged at 400 K. Steam enters the turbine of the vapor power cycle at 8 MPa, 400 "C, and expands to the condenser pressure of 8 kPa. Water enters the pump as saturated liquid at 8 kPa. The turbine and pump of the vapor cycle have isentropic efficiencies of 90 and 80%, respectively. Determine: a. The specific enthalpy of all streams, in ki/kg. b. The mass flow rates of the air and the steam, each in kg/s The net power developed by the gas turbine and vapor power cycle, each in MW d. The combustor heat load, in MW C. e. The thermal efficiency T-1400 K 3 P P1200 kPa = 88% Combustor n-84% Gas turbine Compressor Turbine We-We T 300 K +1 P- 100 kPa Air inlet Exhaust T 400 K Ps P 100 kPa 5 T, 400C P 8 MPa 90% Heat-recovery steam generator Turbine W w-w Vapor cycle fr Condenser Pump P Ps 8kPa n-80%

Answer 1

us Tunbine Let cpz.ooS KS Compresson h-1A to n ain W 300 100KPa B1200kp 300 X - 610K -84 T2T > 842 610- 300 T1- 30 D -T, T6 K a Tun bine T300n V -4 och1- Ty Ty n 8 99 Ts T3-Ty T3-Ty Tys6K 88 082 1y00 Ty' 899 p C T2-1 005x (669-300) A <pC73-T4)0os X ( 1y00- 15) LM Cp C T3- 005C 1400-69) = 134.655 A Wnet T 16315KT nd 26.375 346550- 37.62V.

Vapor eycde 0) T400 P8 MPa h393K S1 636 5 KJ 63651 593 t x6 1-634 (Tunbine ex haus 15 6 562402-35)- 1990 hg- 113-85 t b. = 1.ob 3139.3-1490 3139:3- ha hg' 2104.9 K /iz (80-.08) banxK X "р: V4р 100 KJ 449 h4 h T33.85 K5 h6 pt hq - q.4qt 72 8S 183.84 netT Ch-hg)9-99 Wnet 3139.3- 2104.9- 9.99 l°24.4 Q h6 31393- 162-6Ye 295543

ne 1024.4 2 00)X 24.667 29SS.y Паxсрах СТу -T5) - nx Chg-h) ma m x 2.455.4) 8.26 m (6oh-5kSoo- net 45 Mu usx103 K hax 216315 t ms x1024.4 450 Kl fut the vdue 626 CMess ob steam Nou) hlo ans13.6 12 Ma C . Wnet 216-315 112 31000 Kwa3 M Wnpane 10244 12 2 14000 k2 |4 MV combulan ed Jo ade 334 655 XI12-y- 82-S N 1 Пathy -C1gxn 31623466 e 2 C31622466o059-21