Power Plant Engineering Mcq Questions Pdf

81. Burning of low grade fuel can be improved by

(a) pulverizing.
(b) blending with better quality coals.
(c) oil assisted ignition.
(d) any of the above.

82. Which one is essential for combustion of fuel ?

(a) Oxygen.
(b) Correct fuel-air ratio.
(c) Proper ignition temperature.
(d) All of the above three.

83. The percentage of 0₂ in atmospheric air is

(a) 21 % by volume.
(b) 23 % by weight.
(c) 79 % by volume and 77% by weight.
(d) both (a) and (b).

84. The proper indication of incomplete combustion is

(a) the smoking exhaust from chimney.
(b) high temperature of flue gas.
(c) high CO content in flue gases at exit.
(d) high CO₂ content in flue gases at exit.

85. The stoker used in large capacity boilers, when un-pulverized coal is used, is

(a) overfeed stoker.
(b) underfeed stoker.
(c) any of the above.
(d) none of the above.

86. Overfeed stoker includes

(a) travelling grate.
(b) chain grate.
(c) spreader.
(d) all of the above.

87. The equipment used for supplying coal to the boiler, when un-pulverized coal is being used, is

(a) skip hoist.
(b) stoker.
(c) any of the above.
(d) none of the above.

88. Capacity of the underfeed stoker is in the range of coal burned per hour.

(a) 100 — 250 kg
(b) 100 — 500 kg
(c) 100 — 2,000 kg
(d) 100 — 5,000 kg

89. Travelling grate stoker can burn coal at the rate of

(a) 50 to 75 kg/m²h
(b) 75 to 100 kg/m²h
(c) 100 to 150 kg/m²h
(d) 150 to 200 kg/m²h

90. Pulverized coal is

(a) non-smoking coal.
(b) coal free from ash.
(c) coal broken in fine particles.
(d) coal which burns for long time.

91. Equipment used for pulverizing the coal is the

(a) hopper.
(b) stoker.
(c) ball mill.
(d) burner.

92. Pulverized fuel is used for

(a) better burning.
(b) increased calorific value of coal.
(c) less radiation loss.
(d) medium size units.

93. The advantages of using pulverized fuel include

(a) higher boiler efficiency, low air requirement and low fan power.
(b) easy and complete combustion.
(c) fast response to load changes and low banking losses.
(d) all of the above.

94. The drawbacks of using pulverized fuel include

(a) additional investment in pulverizing plant and stack fly-ash removal equipment.
(b) extra power requirements for the pulverizing plant.
(c) reduced power plant efficiency.
(d) both (a) and (b).

95. Ash is the main waste product of steam power plants with low grade coal (may be in tonnes per day). This ash

(a) can be used in building construction.
(b) can be used in brick making near the plant side.
(c) it can be dumped in disused mines, river or sea or in an area excavated in the waste land, as the case may be.
(d) all of the above.

95. Fly-ash generally results from

(a) fluidized bed boilers.
(b) pulverized coal boilers.
(c) diesel engines.
(d) gas turbines.

96. Dust can be separated from gas by

(a) impingement upon small baffles.
(b) sudden velocity decrease owing to enlargement.
(c) abrupt changes of flow direction.
(d) any of the above.

97. Which of the following equipment is installed in steam power plants to reduce air pollution ?

(a) De-super-heater.
(b) Air filter.
(c) Air electrostatic precipitator.
(d) Stack.
(e) None of them.

98. In coal-fired thermal power stations, what are the electrostatic precipitators used for?

(a) To remove dust particles settling on the bus bar conductors in the station switchyard.
(b) To condense steam by electrostatic means.
(c) To keep the air heaters clean.
(d) To collect the dust particles from the flue gases.

99. Electrostatic precipitator is installed between

(a) induced fan and chimney.
(b) air pre-heater and induced fan.
(c) economizer and air pre-heater.
(d) boiler furnace and economizer.

100. The draught produced by a chimney is called the

(a) forced draught.
(b) induced draught.
(c) natural draught.
(d) balanced draught.