Related Questions

Thermal conductivity based continuous flue gas analyser makes use of varying thermal conductivity of the constituents of flue gases. Which of the following constituents of flue gases has the maximum thermal conductivity?
A CO2
B N2
C O2
D CO
Use of pulverised coal in boilers provides
A Higher calorific value
B Better combustion
C Smokeless burning
D Less erosion on furnace wall
Coal is pulverised before burning in large capacity boiler furnaces mainly to
A Ensure its complete combustion
B Facilitate easy ash removal
C Enhance its calorific value
D Provide trouble free operation
The ratio of the energy required to produce the artificial draught (expressed in meters head or J/kg of flue gas) to the mechanical equivalent of extra heat carried away per kg of flue gases due to natural draught, is known as
A Efficiency of the boiler
B Efficiency of the chimney
C Efficiency of the fan
D Power of the boiler
Combustion of pulverised coal as compared to that of lump coal
A Develops a non-luminous flame
B Develops a low temperature flame
C Can be done with less excess air
D Provides a lower rate of heat release
Combustion of pulverised coal compared to the lumpy coal
A Provides better control of furnace temperature
B Facilitates combustion with lower excess air
C Provides higher thermal efficiency & flame temperature
D All of the above
Very high pressure boilers are usually __________ boilers.
A Fire tube
B Water tube
C Waste heat
D Natural circulation
Continuous flue gas analyser makes use of paramagnetic properties of some of its constituents, which move towards the strongest part of the magnetic field thus displacing diamagnetic gases. Which of the following gases is diamagnetic?
A CO2
B O2
C NO
D NO2
The excess air required for the combustion of pulverised coal is of the order of about __________ percent.
A 5
B 15
C 30
D 45
Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.
A 1000
B 4000
C 6000
D 8000

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