A combined gas-steam-turbine powerplant is designed with four 45 -MW gas turbines and one 100- MW...

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A combined gas-steam-turbine powerplant is designed with four 45 -MW gas turbines and one 100- MW steam turbine. Each gas turbine operates with compressor inlet temperature 505°R, turbine inlet temperature 2450°R, pressure ratio for both compressor and turbine 5, and compressor and turbine polytropic and mechanical efficiencies 0.87 and 0.96. The gases leaving the turbines go to a heat-recovery boiler then to a regenerator with an effectiveness of 0.87. The turbine gases correspond to 200 percent of theoretical air. The steam cycle has a turbine steam inlet at 1200 psia and 1560°R, one open-type feedwater heater (not optimally placed) with feedwater temperature to heat-recovery boiler at 920°R, condenser pressure 1 psia, and turbine polytropic and mechanical efficiencies 0.90 and 0.95. All electric generator efficiencies are 0.98. Supplementary firing at full load raises the gas temperature to 2000°R. Draw the cycle flow and T-s diagrams and find (a) the required steam mass flow rate in the steam turbine in pound mass per hour, (h) the required air mass flow rate in each gas turbine in pound mass per hour, (c) the heat added in the gas cycle and in supplementary firing at full load, (d) the stack gas temperature in degrees Fahrenheit, (e) the cycle efficiency at full load, and (f) the efficiency at startup when only one gas turbine is used at its full load with no supplementary firing or regeneration. (Ignore the steam cycle pump work.) A combined gas-steam-turbine powerplant is designed with four 45 -MW gas turbines and one 100- MW steam turbine. Each gas turbine operates with compressor inlet temperature 505°R, turbine inlet temperature 2450°R, pressure ratio for both compressor and turbine 5, and compressor and turbine polytropic and mechanical efficiencies 0.87 and 0.96. The gases leaving the turbines go to a heat-recovery boiler then to a regenerator with an effectiveness of 0.87. The turbine gases correspond to 200 percent of theoretical air. The steam cycle has a turbine steam inlet at 1200 psia and 1560°R, one open-type feedwater heater (not optimally placed) with feedwater temperature to heat-recovery boiler at 920°R, condenser pressure 1 psia, and turbine polytropic and mechanical efficiencies 0.90 and 0.95. All electric generator efficiencies are 0.98. Supplementary firing at full load raises the gas temperature to 2000°R. Draw the cycle flow and T-s diagrams and find (a) the required steam mass flow rate in the steam turbine in pound mass per hour, (h) the required air mass flow rate in each gas turbine in pound mass per hour, (c) the heat added in the gas cycle and in supplementary firing at full load, (d) the stack gas temperature in degrees Fahrenheit, (e) the cycle efficiency at full load, and (f) the efficiency at startup when only one gas turbine is used at its full load with no supplementary firing or regeneration. (Ignore the steam cycle pump work.)

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The image shows a combined gassteam turbine power plant These types of power plants are more efficient than traditional power plants because they use ... View the full answer