176. Maximum energy loss in a boiler occurs due to
A.Unbumt carbon in ash
B.Incomplete combustion
C.Ash content
D.Flue gases
177. Overfire burning is the phenomenon of
A.Supply of excess air
B.Supply of excess coal
C.Burning CO and unburnts in upper zone of furnace by supplying more air
D.Fuel bed firing
178. Which is not the correct statement about moisture ir al
A.Inherent moisture and surface moisture are different things
B.In some coals moisture may be present upto 40%
C.Some moisture in coal helps in better burning which is not possible with completely dry coal
D.It increases thermal efficiency
179. Deaeration of feed water is carried out because it reduces
A.Cavitation of boiler feed pumps
B.Corrosion caused by oxygen
C.Heat transfer coefficient
D.PH value of water
180. A supercritical boiler is one that operates above the pressure and temperature of following values
A.100 kg/cm2 and 540°C
B.1 kg/cm2 and 100°C
C.218 kg/cm2 abs and 373°C
D.218 kg/cm2 abs and 540°C
181. Natural water circulation, by convection in water tube boilers; with increase in pressure of boiler
A.Increases
B.Decreases
C.Remains unaffected
D.First increases and then decreases
182. The steam temperature with increase in load in case of a boiler fitted with radiation superheater
A.Increases
B.Decreases
C.Remains unaffected
D.First increases and then decreases
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