391. Blast furnace gas compared to coke oven gas has
Lower ignition temperature
Narrower limit of inflammability
Higher calorific value
Lower theoretical flame temperature
✅ The correct answer is option D.
Fuel and Combustion MCQs
392. Pure carbon is completely burnt in oxygen. The flue gas analysis is 70%CO₂, 20%CO and 10%O₂. The percent excess oxygen used is
20
12.5
0
10
✅ The correct answer is option C.
393. Preheating of a gaseous fuel results in increased
Flame length
Flame temperature
Quantity of flue gas
Ignition temperature
✅ The correct answer is option B.
394. Combustion of pulverised coal as compared to that of lump coal
Develops a non-luminous flame
Develops a low temperature flame
Can be done with less excess air
Provides a lower rate of heat release
✅ The correct answer is option C.
395. Dry air required to burn 1 kg of carbon completely may be around __________ kg.
11
2
20
38
✅ The correct answer is option A.
396. __________ present in coal is not determined in its ultimate analysis.
Fixed carbon
Total carbon
Hydrogen
Nitrogen
✅ The correct answer is option A.
397. Initial pressure of oxygen introduced into the ‘bomb’ of the bomb calorimeter for determination of calorific value of coal/fuel oil may be around __________ atm.
3-May
25-30
60-65
95-100
✅ The correct answer is option B.
398. Efficient burning of anthracite coal requires
Low preheat of air
Fine grinding
High excess air
All of the above
✅ The correct answer is option B.
399. Anthracite coal
Contains more volatile matter than bituminous coal
Ignites more easily than bituminous coal
Is essentially a coking coal
Burns with short, bluish, yellow-tipped flame producing very little smoke
✅ The correct answer is option D.
400. Which of the following is a primary fuel?
Blast furnace coke
Gasoline
Natural gas
Wood charcoal
✅ The correct answer is option C.