431. During combustion of coal on grate, clinker formation is increased by the
Use of thick fire bed
Low fusion point of ash (< 1100° C)
Use of preheated primary air
All of the above
✅ The correct answer is option D.
Fuel and Combustion MCQs
432. Increase in ash content of blast furnace coke
Reduces its consumption in the furnace
Increases its consumption in the furnace
Does not affect its consumption in the furnace
Decreases its hardness and abrasion resistance
✅ The correct answer is option B.
433. Which of the following combustibles is absent in blast furnace gas?
H₂
CH₄
CO
None of these
✅ The correct answer is option B.
434. Calorific value of wood gas is about __________ kcal/Nm³.
1500
3300
5400
8500
✅ The correct answer is option B.
435. Calorific value of coke even gas produced by low temperature carbonisation of coal is about __________ Kcal/Nm³.
4000
2500
6500
10000
✅ The correct answer is option C.
436. Weathering of coal during storage causes
Reduction in coal size
Increase in its friability
Decrease in its caking capacity
All of the above
✅ The correct answer is option D.
437. During combustion of a gaseous fuel, the presence of a non-luminous flame is an indication of the
Incomplete combustion
Complete combustion
High oxygen in flue gas
None of these
✅ The correct answer is option B.
438. Which of the following has the highest flame speed?
CO
H₂
CH₄
C₂H₆
✅ The correct answer is option B.
439. Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its
Emissivity factor is higher
Sulphur content is lower
Flue gas has lower dew point thereby facilitating more waste heat recovery
All of the above
✅ The correct answer is option D.
440. Which of the following fuel gases will require maximum amount of air for combustion of 1 Nm³ gas ?
Blast furnace gas
Natural gas
Producer gas
Water gas
✅ The correct answer is option B.