An ideal cogeneration steam plant is to generate power and 8600 kJ/s of process heat. Steam enters the turbine from the boiler 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. Show the cycle on a T-s diagram with respect to saturation lines, and determine (a) the mass flow rate of steam that must be supplied by the boiler, (b) the net power produced by the plant, and (c) the utilization factor.
FIGURE P10–76
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Thermodynamics: An Engineering Approach
- 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_forwardSteam is generated at a pressure of 8MPa and leaves the steam generator at 450°C. After the expansion to 700 kPa, the steam undergoes reheat and expands again in a low-pressure turbine. the condenser pressure is 8kPa. The steam flows at the rate of 2.63 x 10 ^ 5 kg/h. If the power plant operates in a Rankine cycle, determine the net power generated and heat transfer in the condenser.arrow_forwardConsider 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. bur Pamp 11 Posess 1-0 (2) Mong 1 hamber Harbie Condenser EST ATWarrow_forward
- 1. In a steam power plant, steam is supplied to the high-pressure turbine at 2800 kPa and 648 K. It is expanded to 558 kPa and sent to the boiler where it is heated to 558 kPa and 648 K. It is then expanded to a final pressure of 2.5 kPa in the low-pressure turbine. Determine: (a) The ideal reheat cycle efficiencyarrow_forwardIn a Rankine cycle with reheating, the steam leaves the boiler at 2.5 MPa and 600 ºC and enters the high pressure turbine where it expands to a pressure of 1 MPa to be then subjected to a reheating process from where it leaves at 1 MPa and 600 ° C. The steam at these conditions enters the low pressure turbine and expands up to the condenser pressure of 50 kPa. The heat that is extracted in the condenser is 1500 kJ / s. If the adiabatic efficiency of the turbines and the pump is 95%, determine the total heat flow in kJ / s delivered to the boiler.arrow_forwardIn a Rankine cycle with reheating, the steam leaves the boiler at 2.5 MPa and 600 ºC and enters the high-pressure turbine where it expands to a pressure of 1 MPa to be then subjected to a reheating process from where it leaves at 1 MPa and 600 ° C. The steam at these conditions enters the low-pressure turbine and expands up to the condenser pressure of 50 kPa. The heat that is extracted in the condenser is 1500 kJ / s. If the adiabatic efficiency of the turbines and the pump is 95%, determine the total heat flow in kJ / s delivered to the boiler.arrow_forward
- Steam 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_forwardIn a steam power plant operating according to the ideal Rankine cycle at 4MPa pressure and 400CIt enters and condenses in the condenser at a pressure of 100kPa. Determine the efficiency of the cycle.What would the efficiency be if the steam entered the turbine at 5MPa pressure and condensed at 90kPa pressure.arrow_forwardA steam turbine cycle running on a Rankin cycle between a condenser pressure of 10 kPa and a boiler pressure of 20 MPa, the steam enters the high pressure turbine at a temperature of 600 ° C. The average turbine expands to 800 kPa and then enters the boiler again to be reheated to 500 ° C. The steam leaves the boiler to a low pressure turbine, where it expands to the condenser pressure. If the expansion and compression in the turbine and the pump is isotropic, and the addition of heat is constant pressure, find the efficiency of the cycle. Note point # 1 at the vapor exit region of the condenserarrow_forward
- Steam is generated in the boiler of a cogeneration plant at 9 MPa and 450C at a steady rate of 5 kg/s. In normal operation, steam expands in a turbine to a pressure of 0.5 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. Draw the schematic and T-S diagrams. Label the points by setting point 1 at the condenser outlet, point 2 at the 1st pump (after the condenser) outlet, point 3 at the process heater outlet, point 4 at the 2nd pump (after the process heater) outlet, point 5 at the boiler inlet, point 6 at the boiler outlet, point 7 at the process heater inlet, and point 8 at the condenser inlet. Use 2 decimal places for the enthalpy and other energies in solving and for the final answers. For the steam quality (x) and entropy (s), use 4 decimal places in solving. For the specific…arrow_forwardSteam is generated in the boiler of a cogeneration plant at 9 MPa and 450C at a steady rate of 5 kg/s. In normal operation, steam expands in a turbine to a pressure of 0.5 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. Draw the schematic and T-S diagrams. Label the points by setting point 1 at the condenser outlet, point 2 at the 1st pump (after the condenser) outlet, point 3 at the process heater outlet, point 4 at the 2nd pump (after the process heater) outlet, point 5 at the boiler inlet, point 6 at the boiler outlet, point 7 at the process heater inlet, and point 8 at the condenser inlet. Use 2 decimal places for the enthalpy and other energies in solving and for the final answers. For the steam quality (x) and entropy (s), use 4 decimal places in solving. For the specific…arrow_forwardConsider 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 mass flow rate of steam produced by the boiler. Assume an isentropic efficiency of 87% for both the turbine and the pump.arrow_forward
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