# Assignment 1 POWAB ZC315 46b5d9dd24a358d04c2294cf9e81ad20

```BIRLA INSTITUTE OF TECHNOLOGY AND SCIENCE, PILANI
Work-Integrated Learning Programmes Division
Semester II - 2019-2020
Assignment 1
Course No: POWAB ZC315
Course Name: Power Plant Engineering
Instructions: All questions are compulsory and carries equal marks
Due Date: 27/03/2020
Marks: 10 (5% weightage)
Attempt all questions in a sequence
Assume suitable data wherever necessary and highlight it
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Q.1
a. In detail, explain the power scenario in India and its way ahead.
b. With the help of suitable example, write down the relative advantages and
Q.2
A hydro-electric plant costs Rs 3000 per kW of installed capacity. The total annual
charges consist of 5% as interest; depreciation at 2%, operation and maintenance at
2% and insurance, rent etc. 1.5%. Determine a suitable two-part tariff if the losses in
transmission and distribution are 12.5% and diversity of load is 1.25. Assume that
maximum demand on the station is 80% of the capacity and annual load factor is 40%.
What is the overall cost of generation per kWh?
Q.3
A steam power plant operates on the reheat Rankine cycle. Steam enters the highpressure turbine at 12.5 MPa and 550&deg;C at a rate of 7.7 kg/s and leaves at 2 MPa.
Steam is then reheated at constant pressure to 450&deg;C before it expands in the lowpressure turbine. The isentropic efficiencies of the turbine and the pump are 85
percent and 90 percent, respectively. Steam leaves the condenser as a saturated
liquid. If the moisture content of the steam at the exit of the turbine is not to exceed
5 percent, determine (a) the condenser pressure, (b) the net power output, and (c)
the thermal efficiency.
Q.4
A steam power plant operates on an ideal regenerative Rankine cycle. Steam enters
the turbine at 6 MPa and 450&deg;C and is condensed in the condenser at 20 kPa. Steam
is extracted from the turbine at 0.4 MPa to heat the feedwater in an open feedwater
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heater. Water leaves the feedwater heater as a saturated liquid. Show the cycle on a
T-s diagram, and determine
(a) The net work output per kilogram of steam flowing through the boiler, and
(b) The thermal efficiency of the cycle
(c) Repeat Prob. 4 by replacing the open feedwater heater with a closed feedwater
heater. Assume that the feedwater leaves the heater at the condensation
temperature of the extracted steam and that the extracted steam leaves the
heater as a saturated liquid and is pumped to the line carrying the feedwater.
Q.5
Consider a combined gas–steam power cycle as shown in the figure. The topping cycle
is a simple Brayton Cycle that has a pressure ratio of 7. Air enters the compressor at
15&deg;C at a rate of 10 kg/s and the gas turbine at 950&deg;C. The bottoming cycle is a reheat
Rankine cycle between the pressure limits of 6 MPa and 10 kPa. Steam is heated in a
heat exchanger at a rate of 1.15 kg/s by the exhaust gases leaving the gas turbine and
the exhaust gases leave the heat exchanger at 200&deg;C. Steam leaves the high-pressure
turbine at 1.0 MPa and is reheated to 400&deg;C in the heat exchanger before it expands
in the low pressure turbine. Assuming 80 percent isentropic efficiency for all pumps
and turbine, determine:
(a) moisture content at the exit of the low-pressure turbine,
(b) steam temperature at the inlet of the high-pressure turbine,
(c) net power output and the thermal efficiency of the combined plant.
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