41. Coal containing large quantity of __________ are difficult to wash.
Ash
Inherent mineral matter
Free impurities
Volatile matter
✅ The correct answer is option B.
Fuel and Combustion MCQs
42. The main function of primary air in pulverised coal fired burner is to
Burn CO to CO₂
Dry and transport the coal
Have proper combustion by supplying it around the burner
Preheat the tertiary air used for complete combustion of CO to CO₂
✅ The correct answer is option B.
43. Which of the following is not a ‘manufactured’ fuel?
LPG
Coal briquettes
Tar
Colloidal fuels
✅ The correct answer is option C.
44. To avoid fire by spontaneous combustion of coal due to its low temperature oxidation, it should be stored in
Shallow and small piles
Fine sizes without the presence of any lump
Closed space without any ventilation facility
Large heaps with small surface to volume ratio
✅ The correct answer is option A.
45. ‘Fat coals’ are those coals which have very high
Caking capacity
Volatile matter content
Fusion point of its ash
Inherent moisture content
✅ The correct answer is option A.
46. A coal with high ash content
Has higher calorific value
Is harder and stronger
Is not subjected to washing
Has low quantity of mineral matter
✅ The correct answer is option B.
47. The reaction, C + CO₂ ⟷ 2CO, taking place during coal gasification is called the __________ reaction. n.
Neumann reversal
Shift conversion
Boudouard
Reduction
✅ The correct answer is option C.
48. Higher efficiency in the combustion of solid fuel can not be achieved by
Proper fuel preparation
Keeping the flue gas exhaust temperature very high
Adopting efficient-fuel firing technique & equipment
Supplying correct quantity of combustion air
✅ The correct answer is option B.
49. Lignite is
A high rank coal
A coking coal
Can be used for gasification and steam generation
A black banded coal which burns with a non-smoky yellowish flame
✅ The correct answer is option C.
50. Grindability index of a coal is 100. It implies that the
Coal can be pulverised with great difficulty
Coal can’t be pulverised
Coal can be easily pulverised
Power consumption in grinding the coal will be very high
✅ The correct answer is option C.