Consider a cogeneration power plant that is modified with reheat and that produces 3 MW of power and supplies 7 MW of process heat. Steam enters the high-pressure turbine at 8 MPa and 500°C and expands to a pressure of 1 MPa. At this pressure, part of the steam is extracted from the turbine and routed to the process heater, while the remainder is reheated to 500°C and expanded in the low-pressure turbine to the condenser pressure of 15 kPa. The condensate from the condenser is pumped to 1 MPa and is mixed with the extracted steam, which leaves the process heater as a compressed liquid at 120°C. The mixture is then pumped to the boiler pressure. Assuming the turbine to be isentropic, show the cycle on a T-s diagram with respect to saturation lines, and disregarding pump work, determine (a) the rate of heat input in the boiler and (b) the fraction of steam extracted for process heating.
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Thermodynamics: An Engineering Approach ( 9th International Edition ) ISBN:9781260092684
- An ideal cogeneration steam plant is to generate power and 9400 kJ/s of process heat. Steam enters the turbine from the boller at 7 MPa and 500°C. One-fourth of the steam is extracted from the turbine at 600 kPa pressure for process heating. The remainder of the steam continues to expand and exhausts to the condenser at 10 kPa. The steam extracted for the process heater is condensed in the heater and mixed with the feedwater at 600 kPa. The mixture is pumped to the boiler pressure of 7 MPa. (5) ↑ Boiler Pump II 6 O process process Process heater (3) Turbine (D) Condenser Pump I Show the cycle on a T-s diagram with respect to saturation lines. (8) 1arrow_forwardAn Ideal cogeneration steam plant is to generate power and 9400 kJ/s of process heat. Steam enters the turbine from the boller at 7 MPa and 500°C. One-fourth of the steam is extracted from the turbine at 600 kPa pressure for process heating. The remainder of the steam continues to expand and exhausts to the condenser at 10 kPa. The steam extracted for the process heater is condensed in the heater and mixed with the feedwater at 600 kPa. The mixture is pumped to the boller pressure of 7 MPa. 5 Boiler Pump II process Process heater 1-Ⓡ Determine the net power produced by the plant. The net power produced by the plant is [ KW. Turbine Condenser Pump I - (8)arrow_forwardAn Ideal cogeneration steam plant is to generate power and 9400 kJ/s of process heat. Steam enters the turbine from the boller at 7 MPa and 500°C. One-fourth of the steam is extracted from the turbine at 600 kPa pressure for process heating. The remainder of the steam continues to expand and exhausts to the condenser at 10 kPa. The steam extracted for the process heater is condensed in the heater and mixed with the feedwater at 600 kPa. The mixture is pumped to the boller pressure of 7 MPa. 5 Boiler Pump II process Process heater 1-Ⓡ Turbine Condenser Pump I - (8) Determine the mass flow rate of steam that must be supplied by the boller. Use steam tables. The mass flow rate of steam that must be supplied by the boller is kg/s.arrow_forward
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- Steam is generated in the boiler of a cogeneration plant at 10 MPa and 450C at a steady rate of 5 kg/s. In normal operation, steam expands in a turbine to a pressure of0.5 MPa and is then routed to the process heater, where it supplies the process heat. Steam leaves the process heater as a saturated liquid and is pumped to the boiler pressure. In this mode, no steam passes through the condenser, which operates at 20 kPa. (a) Determine the power produced and the rate at which process heat is supplied in this mode. (b) Determine the power produced and the rate of process heat supplied if only 60 percent of the steam is routed to the process heater and the remainder is expanded to the condenser pressurearrow_forwardSteam is generated in the boiler of a cogeneration plant at 10 MPa and 450C at a steady rate of 5 kg/s. In normal operation, steam expands in a turbine to a pressure of0.5 MPa and is then routed to the process heater, where it supplies the process heat. Steam leaves the process heater as a saturated liquid and is pumped to the boiler pressure. In this mode, no steam passes through the condenser, which operates at 20 kPa. Determine the WP TOTAL in kJ/kg.arrow_forwardSuperheated water vapor enters the turbine at 5Mpa and 4000C. The water leaves the condenser as saturated liquid at a pressure of 30kPa, and the turbine efficiency is 91%. The net power output of the cycle is 100MW. Determine the thermal efficiency.arrow_forward
- Consider a 150-MW steam power plant that operates on a simple Rankine cycle. Steam enters the turbine at 7 MPa and 500°C and is cooled in the condenser at 10 kPa. Calculate the volume flow rate of sea water (S.G. = 1.05) used in the condenser, if the allowable temperature rise is 5°C. Assume an isentropic efficiency of 87% for both the turbine and the pump.arrow_forwardConsider an 80 MW coal-fired steam power plant that runs on a reheat Rankine cycle. Steam enters the high-pressure turbine at 10 MPa and 500°C and the low-pressure turbine at 1 MPa and 500°C. Steam leaves the condenser as a saturated liquid at 10 kPa. Determine the mass flow rate of steam from the boiler. in metric tons per hourarrow_forwardSteam enters the high-pressure turbine of a steam power plant that operates on the ideal reheat Rankine cycle at 800 psia and 900F and leaves as saturated vapor. Steam is then reheated to 800F before it expands to a pressure of 1 psia. Heat is transferred to the steam in the boiler at a rate of 6 * 104 Btu/s. Steam is cooled in the condenser by the cooling water from a nearby river, which enters the condenser at 45F. Show the cycle on a T-s diagram with respect to saturation lines, and determine (a) the pressure at which reheating takes place, (b) the net power output and thermal efficiency, and (c) the minimum mass flow rate of the cooling water required.arrow_forward
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