A combined cycle power plant is designed with four-150 MW gas turbines and one-350 MW steam...

   

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A combined cycle power plant is designed with four-150 MW gas turbines and one-350 MW steam turbine. The exhaust gases from each gas turbine pass through a supplementary firing chamber. Then the exhaust gases pass through a waste heat boiler to generate a superheated steam. The generated superheated steam from the four waste heat boilers are supplied to the steam turbine. The detailed given inputs are shown in the attached figure. a 25C 1 bar (Inlet & reference point) C 7c = 0.85 The feed water to the other typical three waste heat boilers Fuel (calorific value=44000 kJ kg) ncc = 0.96 Tp.c = Tp.t = 8 Fuel (calorific value-44000 kJ kg) 1SF = 0.96 850C "WHB = 0.85 7 DAH 2 5 1100 C d GT nt = 0.9 ST PGT.net4 150 MW 3 The generated steam from the other typical three waste heat boilers G PST = 350 MW G For the states of the steam cycle, use the following properties: Pressure (bar) Temperature (C) 550 80 20 0.07 0.07 State 1 2 3 4 5 6 7 . 20 20 80 Enthalpy (kJ/kg) 3522 3133 2275 163.4 163.4 908.5 908.5 For the gas turbine plants and the steam plant, mechanical and generator efficiencies of 0.99 and 0.98, respectively. Assume for air (Cp.a = 1.003 kJ/kg.K and Ya = 1.4) and for gases (Cpg 1.15 kJ/kg.K and Yg = 1.33). Calculate: a. The air mass flow rate to each gas turbine plant. b. The fuel mass flow rate required in each gas-turbine cycle and in each of the supplementary firing. The generated steam mass flow rate by the heat recovery boiler. The gas stack temperature after the waste heat boiler. The efficiencies of gas, steam and combined cycles. C. d. e. A combined cycle power plant is designed with four-150 MW gas turbines and one-350 MW steam turbine. The exhaust gases from each gas turbine pass through a supplementary firing chamber. Then the exhaust gases pass through a waste heat boiler to generate a superheated steam. The generated superheated steam from the four waste heat boilers are supplied to the steam turbine. The detailed given inputs are shown in the attached figure. a 25C 1 bar (Inlet & reference point) C 7c = 0.85 The feed water to the other typical three waste heat boilers Fuel (calorific value=44000 kJ kg) ncc = 0.96 Tp.c = Tp.t = 8 Fuel (calorific value-44000 kJ kg) 1SF = 0.96 850C "WHB = 0.85 7 DAH 2 5 1100 C d GT nt = 0.9 ST PGT.net4 150 MW 3 The generated steam from the other typical three waste heat boilers G PST = 350 MW G For the states of the steam cycle, use the following properties: Pressure (bar) Temperature (C) 550 80 20 0.07 0.07 State 1 2 3 4 5 6 7 . 20 20 80 Enthalpy (kJ/kg) 3522 3133 2275 163.4 163.4 908.5 908.5 For the gas turbine plants and the steam plant, mechanical and generator efficiencies of 0.99 and 0.98, respectively. Assume for air (Cp.a = 1.003 kJ/kg.K and Ya = 1.4) and for gases (Cpg 1.15 kJ/kg.K and Yg = 1.33). Calculate: a. The air mass flow rate to each gas turbine plant. b. The fuel mass flow rate required in each gas-turbine cycle and in each of the supplementary firing. The generated steam mass flow rate by the heat recovery boiler. The gas stack temperature after the waste heat boiler. The efficiencies of gas, steam and combined cycles. C. d. e.