Reduced NOx formation in flue gas
Lower furnace operating temperature
High heat transfer rate
All of the above
✅ The correct answer is option D.
Fuel and Combustion MCQs
Which of the following fuel gases has the highest calorific value ?
Natural gas
Coal bed methane (CBM)
Liquefied petroleum gas (LPG)
Sewage gas
✅ The correct answer is option C.
A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be
More
Less
Same
Data insufficient; can’t be predicted
✅ The correct answer is option C.
Tar is a better fuel than furnace oil, because of its
Higher calorific value
Lower sulphur content
Higher emissivity (0.8 – 0.9) resulting in higher radiation heat transfer rate
Both A & B
✅ The correct answer is option D.
Artificial draught produced by a fan can be controlled by the
Speed of the fan
Damper
Variation in the pitch of the fan blades
All of the above
✅ The correct answer is option D.
For every 10% increase in the excess air; the fuel consumption increases by __________ percent.
0.1
2
5
10
✅ The correct answer is option A.
Improper storage condition results in the weathering of coal and spontaneous combustion, which increases its
Caking index
Yield of carbonised products
Friability & oxygen content
Calorific value
✅ The correct answer is option C.
With increase in the time of carbonisation at a particular temperature (say 1000°C), the __________ percentage in coke oven gas increases.
Hydrogen
Methane
Unsaturated hydrocarbons
All of the above
✅ The correct answer is option A.
Fischer-Tropsch method aims at the
Gasification of coal
Synthesis of gasoline (from water gas)
Hydrogenation of coal to produce gasoline
None of these
✅ The correct answer is option B.
Coal containing large quantity of __________ are difficult to wash.
Ash
Inherent mineral matter
Free impurities
Volatile matter
✅ The correct answer is option B.