Geothermal Power Plant
In a geothermal power plant, the mass flow rate of ground
water is 4000 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?
A.
B.
120 kJ/kg
100 kJ/kg *
C. 200 kJ/kg
D. 150 kJ/kg
Ground water of geothermal power plant has an enthalpy
of 700 kJ/kg and a turbine inlet of 2,750 kJ/kg and enthalpy
of hot water in flash tank is 500 kJ.kg. What is the mass of
steam flow entering the turbine if mass flow of ground water
is 45 kg/s.
A.
B.
4 kg/s *
6 kg/s
C. 8 kg/s
D. 7.1 kg/s
The mass flow rate of ground water in a 20 MW geothermal
power plant is 150 kg/sec 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?
A.
B.
18 kg/sec
24 kg/sec
C. 28 kg/sec *
D. 76 kg/sec
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?
A.
B.
109.37 mᶟ/hr
120.37 mᶟ/hr *
C. 237.6 mᶟ/hr
D. 320.4 mᶟ/hr
A 18,000-kW geothermal plant has a generator efficiency
and turbine efficiency of 90% and 80%, respectively. If the
quality after throttling is 22.5% and each well discharges
400,000 kg/hr, determine the number of wells are required
to produce if the change of enthalpy at entrance and exit of
turbine is 500 kJ/kg.
A.
B.
`
2*
4
C. 6
D. 8
A 25,000 KW geothermal plant has a generator efficiency
and turbine efficiency of 90% and 80%, respectively. If the
quality after throttling is 20% and each well discharges
400,000 kg/hr, determine the number of wells are required
to produce if the change of enthalpy an entrance and exit
of turbine is 312.5 KJ/kg.
A.
B.
1
3
C. 5 *
D. 7
A 16,000 KW geothermal plant has a generator efficiency
and turbine efficiency of 90% and 80%, respectively. If the
quality after throttling is 20% determine the discharge of
each well in kg/hr if the number of wells required is 4. The
change of enthalpy at entrance and exit of turbine is 500
KJ/kg.
A.
B.
100,000
300,000
C. 200,000 *
D. 400,000
In a geothermal power plant, 1500 kg/s of condensate
water at 1.5 MPa in a flash tank and 109 kg/s of steam at a
pressure of 0.7 MPa delivered to the turbine. If the specific
steam consumption of the turbine generator is 3 kg/s/MW,
what will be the power output of the plant in MW?
A.
B.
16.33
26.33
C. 36.33 *
D. 46.33
A liquid dominated geothermal plant with a single flash
separator receives water at 204 oC. 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 60 MW, what is the mass flow rate of the
well-water in kg/s? At 204 oC: hf = 870.51 kJ/kg. At 1.04
MPa: hf = 770.38, hfg = 2009.2, hg = 2779.6, sg = 6.5729.
At 0.034 MPa: hf = 301.40, hfg = 2328.8, sf = 0.9793, sfg =
6.7463.
A.
B.
2,933 *
1,860
A.
B.
89.5 MW
87.5 MW *
C. 65.5 MW
D. 79.5 MW
In a 12 MW geothermal power plant, the mass flow of
steam entering the turbine is 26 kg/sec. The quality after
throttling is 25% and enthalpy of ground water is 750 KJ/kg.
Determine the overall Efficiency of the plant.
A.
B.
9.6%
14.5%
C. 15.4% *
D. 8.6%
A geothermal power plant draws pressurized water from a
well at 20 Mpa and 300°C. To produce a steam water
mixture in the separator, where the un flashed 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 a rated power output of 10 MW. Calculate overall plant
efficiency.
At 20 Mpa and 300°C (Table 4) h1= 1333.3 KJ/kg. At 1.5
Mpa: hf = 844.89 hfg = 1947.3. At 1.5 Mpa (Table 2) h3, =
2792.2 KJ/kg S3 = 6.4448. At 1atm (100°C) Sf = 1.3069,
Sg = 6.048, hf = 419.04, hfg = 2257 KJ/kg.
A.
B.
7.29% *
9.34%
C. 12.34%
D. 15.45%
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?
C. 2,100
D. 2,444
Mass flow rate of ground water in a geothermal power plant
is 1,500,000 kg/hr and the quality after throttling is 30%.
Determine the brake power of turbine if the change of
enthalpy of steam at inlet and outlet is 700 KJ/kg.
A.
B.
2,800
2,100
C. 1,866
D. 2,444 *