150
1500
3500
5000
✅ The correct answer is option B.
Fuel and Combustion MCQs
Function of secondary air in pulverised coal firing is to
Transport the coal to the burner
Dry the coal
Ensure efficient burning of coal around the burner
Reduce primary air requirement
✅ The correct answer is option C.
The most matured coal out of the following is
Lignite
Semi-anthracite
Sub-bituminous
Bituminous
✅ The correct answer is option B.
The lowest temperature, at which a solid fuel produces enough vapors to support continuous combustion, is called
Fire point
Smoke point
Burning temperature
Kindling temperature
✅ The correct answer is option C.
Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher
Calorific value
Higher C/H ratio
Sulphur content
Difference in gross & net calorific value
✅ The correct answer is option B.
High ash coals
Are soft & friable (poor strength and size stability)
Require longer time of carbonisation as ash offers resistance to heat transfer
Produce larger quantity of coke oven gas
None of these
✅ The correct answer is option B.
Which of the following is coking?
Vitrain
Fussain
Both A & B
Neither A nor B
✅ The correct answer is option A.
Which of the following is not applicable to fluidised bed combustion of coal?
It can not burn low grade coal
It achieves higher fuel combustion efficiency
Less heat transfer surface area is required in boilers
None of these
✅ The correct answer is option A.
Washing of coal
Reduces its ash & sulphur content
Improves its coking properties
Increase the fusion point of its ash by removing chlorine compounds
All of the above
✅ The correct answer is option D.
During the carbonisation of coal
All tar is evolved at < 600°C
Evolution of H₂ and formation of methane and aromatics occur at > 700°C
Hard semi-coke starts shrinking at 600°C
All of the above
✅ The correct answer is option D.