Related Questions

__________ fuels require the maximum percentage of 'excess air' for complete combustion.
A Solid
B Liquid
C Gaseous
D Nuclear
Use of excess of combustion air in the combustion of fuels results in
A Heat losses
B Long flame
C Condensation of water vapour from the fuel gas
D None of these
Which of the following would require least amount of secondary air for combustion?
A Coke breeze containing 25% ash and 2% volatile matter
B Anthracite containing 10% volatile matter and 8% ash
C Bituminous coal containing 20% ash and 25% volatile matter
D Semi-bituminous coal containing 25% ash and 20% volatile matter
Supply of excess air for complete combustion of fuel is necessitated to facilitate
A Its thorough mixing with air
B Attainment of chemical equilibrium
C Attainment of high temperature
D None of these
Too much of excess air in combustion results in high
A Fuel consumption for the same heat load
B Stack gas temperature
C Percentage of oxygen in flue gases
D All of the above
The main drawback of supplying more excess air in the combustion of fuel is the
A Excessive power requirement of air blower
B Enhanced sensible heat loss in the flue gas
C Intermittant and uncontrolled combustion of the fuel
D High exit flue gas temperature from the furnace
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
High excess air in combustion of fuels results in
A Increased fuel consumption
B Incomplete combustion
C Smoky flame
D None of these
The optimum percentage of excess air for combustion depends upon the __________ of the fuel.
A Type (solid, liquid or gaseous)
B Calorific value
C Sulphur content
D Ignition temperature
Deficiency of combustion air during combustion of a gaseous fuel
A Lengthens the flame
B Causes heat loss of fuel by its partial combustion
C Both A & B
D Shortens the flame

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