4 The steam cycle of a combined cycle power plant (shown in Figure Q4 below) is to be designed based on a gas turbine un

[answerhappygod]

4 The Steam Cycle Of A Combined Cycle Power Plant Shown In Figure Q4 Below Is To Be Designed Based On A Gas Turbine Un 1 (179.72 KiB) Viewed 73 times

4 The steam cycle of a combined cycle power plant (shown in Figure Q4 below) is to be designed based on a gas turbine unit whose gas flow rate is 60 kg/s and exhaust gas temperature is 600K. Assume pinch temperature is 25K. Steam at 15bar in HRSG is superheated to 300K and expanded through steam turbine to a condenser pressure of 0.03bar. The isentropic efficiency of the steam turbine is estimated to be 80%. Assume feed pump efficiency of 75% for steam cycle. The properties of saturated water and superheated steam are provided in Tables Q4(a) and Q4(b) respectively below. Calculate: (i) The boiler steam generation rate. (ii) The steam turbine power output. (iii) The condition of steam exhausted from the steam turbine. (iv) The efficiency of the steam cycle. (8) (6) (3) (8) Exhaust to Stack Economiser 5 6 لالالال ما Waste heat boiler Evaporator Steam Turbine Feed water 00 Superheater 7 Condenser Feed pump Gas Turbine Figure 24
Entropy (kJ/kg-K) Table 24(a) Properties of Saturated Water (Liquid-Vapour) Specific Enthalpy Volume (kJ/kg) (m3/kg) Press. Temp Sat. Sat. Sat. (bar) (°C) Sat. Liquid Evap. Vapour Liquid Vapour hr hrg hg Sr Va 0.02 17.5 67.01 73 2460 2533 0.261 0.03 24.1 45.67 101 2444 2545 0.354 0.04 29. 34.80 121 2433 2554 0.422 Evap. Sig Sat. Vapour Sg 8.462 8.222 8.051 8.723 8.576 8.473 .. --- 14 15 16 195.0 0.1408 198.3 0.1317 201.4 0.1237 830 845 859 1960 1947 1935 2790 2792 2794 2.284 2.315 2.344 4.185 4.130 4.078 6.469 6.445 6.422 Table Q4(b) Properties of Superheated Steam Press. Tsat Enthalpy Entropy Temperature (°C) (bar) (°C) (kJ/kg) (kJ/kg-K) Sat. Sat. 150 200 250 300 400 500 Vapour Vapour hg Sg 0.01 7.0 2514 8.974 h 2784 2880 2978 3077 3280 3489 S 9.751 9.966 10.16 10.34 10.67 10.96 0.05 32.9 2561 8.394 h 2784 2880 2978 3077 3280 3489 s 9.008 9.223 9.42 9.601 9.927 10.22 ...... 10 179.9 2778 6.586 15 198.3 2792 6.445 h S h S h S 2829 2944 3052 3264 3478 6.6956.926 | 7.124 7.464 7.761 2796 2925 3039 3256 3473 6.452 6.711 6.919 7.268 7.569 2904 3025 3248 3467 6.547 6.768 7.126 | 7.431 20 212.4 2799 6.340 ....... h - Enthalpy kJ/kg; s - Entropy (kJ/kg-K)