The document contains 11 problems related to geothermal power plant design and performance calculations. The problems involve calculating mass flow rates, enthalpies, power output, plant efficiency and other parameters given inputs like water flow rates, temperatures, pressures and thermodynamic properties at different points in geothermal power cycles.
The document contains 11 problems related to geothermal power plant design and performance calculations. The problems involve calculating mass flow rates, enthalpies, power output, plant efficiency and other parameters given inputs like water flow rates, temperatures, pressures and thermodynamic properties at different points in geothermal power cycles.
The document contains 11 problems related to geothermal power plant design and performance calculations. The problems involve calculating mass flow rates, enthalpies, power output, plant efficiency and other parameters given inputs like water flow rates, temperatures, pressures and thermodynamic properties at different points in geothermal power cycles.
The document contains 11 problems related to geothermal power plant design and performance calculations. The problems involve calculating mass flow rates, enthalpies, power output, plant efficiency and other parameters given inputs like water flow rates, temperatures, pressures and thermodynamic properties at different points in geothermal power cycles.
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1. A liquid dominated geothermal plant with a single flash separator receives water at 204°C.
The separator pressure is 1.04 MPa. A direct contact condenser operates at 0.034 MPa. The turbine has a polytropic efficiency of 0.75. For a cycle output of 50 MW, what is the mass flow rate of the well- water in kg/s?
2. A geothermal power plant draws pressurized water from well at 20 MPa and 300°C. To produce a steam-water mixture in the separator, where the unflashed water is removed, this water is throttled to a pressure of 1.5 MPa. The flashed steam which is dry and saturated passes through the steam collector and enters the turbine at 1.5 MPa and expands to 1 atm. The turbine efficiency is 85 % at rated power output of 10 MW. Calculate the over-all plant efficiency.
3. A flashed steam geothermal power plant is located where underground hot water is available as a saturated liquid at 700 kPa. The well head pressure is 600 kPa. The flashed steam enters a turbine at 500 kPa and expands to 15 kPa, when it is condensed. The flow rate from the well is 29.6 kg/s. Determine the power produced in kW.
4. In a certain geothermal area, studies show that 3,300,000 lb/hr of pressurized ground water is available at 2500 psia and 620°F. The water will be throttled to 250 psia to produce wet steam and this mixture will be passed through a water separator to remove the water droplets so that saturated steam at 250 psia is available at the entrance of steam turbine for the proposed power plant. Other data are as follows:
Discharge pressure of turbine: 25 in. Hg vacuum
Turbine Engine efficiency: 75% Mechanical loss: 1.5% Of Shaft Power Generator efficiency: 97%
Assume atmospheric pressure to be 30 in. Hg. Determine the maximum amount of power in kW that the plant can generate, and the mass flow rate of steam entering the turbine.
5. In a certain geothermal area, studies show that 1,500,000 kg/hr of pressurized ground water is available at 17.5 MPa and 330°C. The water will be throttled to 1.7 MPa to produce wet steam and this mixture will be passed through a water separator to remove the water droplets so that saturated steam at 1.7 MPa is available at the entrance of steam turbine for the proposed power plant. Other data are as follows:
Discharge pressure of turbine: 85 kPa vacuum
Turbine Engine efficiency: 73% Mechanical loss: 2% Of Shaft Power Generator efficiency: 95%
Assume atmospheric pressure to be 30 in. Hg. Determine the maximum amount of power in kW that the plant can generate, and the mass flow rate of steam entering the turbine. 6. A flashed steam geothermal plant has pressurized underground water available at 102 kg/cm2 and 240°C. In order to produce steam-water mixture, the ground water is passed and throttled to 5.4 kg/cm2 in a steam separator. The dry steam produced in the separator is fed to double flow impulse and reaction turbine with guaranteed engine efficiency of 85%. The turbine is directly coupled to a 3-phase, 60 Hz, 80% power factor, 13800-V air-cooled generator. Exhaust is to be direct-contact spray type main condenser designed to operate a vacuum of 647.5 mmHg. Generator efficiency is 95%, ground water is 459 kg/s. Determine the following: (a) Enthalpy of steam-water mixture entering the steam separator. (b) Enthalpy of steam entering the turbine. (c) Enthalpy of the exhaust steam in the turbine. (d) Mass flow rate of steam entering the turbine (e) Actual power generated by the plant (in MW) (f) Apparent power (g) Flow rate of the cooling water in the condenser if water from cooling tower enters the condenser at 35°C and leaves at 48°C. (h) How many production wells are needed to supply the plant with pressurized water if each well has a capacity of 127,200 kg/hr? (i) Determine the thermal efficiency of the geothermal plan
7. In a geothermal power plant, the mass flow rate of ground water is 400 kg/s and the quality after throttling is 20%. If the turbine power is 80 MW, what is the change in enthalpy of steam at the inlet and outlet of the turbine?
8. The mass flow rate of ground water in a 20 MW. geothermal power plant is 150 kg/s and its enthalpy is 1000 kJ/kg. If the quality after throttling is 28% and the over-all plant efficiency is 20%, what is the mass flow rate of steam entering the turbine?
9. The turbine power of a geothermal power plant is 2 MW and the enthalpy at the inlet of the turbine is 2500 kJ/kg. Steam flows at the rate of 2.5 kg/s. If the enthalpy at the outlet of the condenser is 300 kJ/kg and the temperature rise of the cooling water is 10°C, what is the volume flow rate of the cooling water?
10. In a geothermal power plant, the enthalpies of the ground water and the turbine inlet are 1500 kJ/kg and 3500 kJ/kg respectively. If the enthalpy of the hot water in the flash tank is 700 kJ/kg and the mass flow rate of steam is 15 kg/s, what is the mass flow rate of ground water?
11. A geothermal energy system consists of a water well, flasher, and a 15 MW Turbine power. The pressurized ground water at 17.5 MPa, 300°C leaves the well to enter the flasher maintained at 1.3 MPa (hf = 814.93 kJ/kg, hfg = 1972.7 kJ/kg). The flashed vapor passes through the separator and collector to enter the turbine as saturated vapor at 1.3 MPa. The turbine exhausts at 1 bar. Find the hourly amount of ground water required in kg/hr.
