In a thermal power plant, steam is obtained from the boiler at 70 bar and 450 °C. This steam is expanded in a high pressure (H.P) turbine to 25 bar and then reheated to 420°C at constant pressure. The steam is then expanded in the intermediate pressure (I.P) turbine. Part of the steam leaving the intermediate pressure turbine is taken to an open exchanger at 180°C (FW) and the remaining steam is taken to a low pressure (L.P) turbine, where it is expanded to 0.07 bar. The isentropic efficiency of the high pressure turbine is 78.5%, the intermediate pressure turbine is and the low pressure turbine has an efficiency of 83%. The boiler has a conversion efficiency of 72%. The mass flow rate of water in the boiler is 15 kg/s. For this system calculate: (a) The net power of the cycle. b) The thermal efficiency of the cycle. c) The amount of coal required each hour in the system. d) The hourly price of coal in the system. NOTE: the first thing to do is to locate the properties of the fluid at each point, and then start making calculations.
In a thermal power plant, steam is obtained from the boiler at 70 bar and 450 °C. This steam is expanded in a high pressure (H.P) turbine to 25 bar and then reheated to 420°C at constant pressure. The steam is then expanded in the intermediate pressure (I.P) turbine. Part of the steam leaving the intermediate pressure turbine is taken to an open exchanger at 180°C (FW) and the remaining steam is taken to a low pressure (L.P) turbine, where it is expanded to 0.07 bar. The isentropic efficiency of the high pressure turbine is 78.5%, the intermediate pressure turbine is and the low pressure turbine has an efficiency of 83%. The boiler has a conversion efficiency of 72%. The mass flow rate of water in the boiler is 15 kg/s. For this system calculate:
(a) The net power of the cycle.
b) The thermal efficiency of the cycle.
c) The amount of coal required each hour in the system.
d) The hourly price of coal in the system.
NOTE: the first thing to do is to locate the properties of the fluid at each point, and then start making calculations.
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