Power Plant Engineering

EXERCISES
1. State how the boilers are classified ?
2. Explain the principle of fire tube and water tube boilers.
3. Describe with a neat sketch the working of Cochran boiler. Show the position of different
mountings and explain the function of each.
4. Describe, giving neat sketches, the construction and working of a Lancashire boiler. Show
the positions of different mountings and accessories.
5. Sketch and describe the working of a Locomotive boiler. Show the positions of fusible plug,
blow off cock, feed check valve and superheater. Mention the function of each. Describe the
method of obtaining draught in this boiler.
6. Give an outline sketch showing the arrangement of water tubes and furnace of a Babcock and
Wilcox boiler. Indicate on it the path of the flue gases and water circulation. Show the posi-
tions of fusible plug, blow off cock and superheater. Mention the function of each.
7. Explain why the superheater tubes are flooded with water at the starting of the boilers ?
8. Mention the chief advantages and disadvantages of fire tube boilers over water tube boilers.
9. Discuss the chief advantages of water tube boilers over fire tube boilers.
10. What are the considerations which would guide you in selecting the type of boiler to be
adopted for a specific purpose ?
11. Distinguish between water-tube and fire-tube boilers and state under what circumstances
each type would be desirable.

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Chapter 6
Chapter 6
Chapter 6
Chapter 6
Chapter 6
Steam T
Steam T
Steam T
Steam T
Steam Turbine
urbine
urbine
urbine
urbine
Steam turbine is one of the most important prime mover for generating electricity. This falls
under the category of power producing turbo-machines. In the turbine, the energy level of the working
fluid goes on decreasing along the flow stream. Single unit of steam turbine can develop power ranging
from 1 mW to 1000 mW. In general, 1 mW, 2.5 mW, 5 mW, 10 mW, 30 mW, 120 mW, 210 mW, 250 mW,
350 mW, 500 mW, 660 mW, 1000 mW are in common use. The thermal efficiency of modern steam
power plant above 120 mW is as high as 38% to 40%.
The purpose of turbine technology is to extract the maximum quantity of energy from the work-
ing fluid, to convert it into useful work with maximum efficiency, by means of a plant having maximum
reliability, minimum cost, minimum supervision and minimum starting time. This chapter deals with the
types and working of various types of steam turbine. The construction details are given in chapter 15.