Theoretically required amount of air
More than theoretically required amount of air
Less than theoretically required amount of air
Theoretically required amount of oxygen
✅ The correct answer is option D.
Fuel and Combustion MCQs
82. Fixed carbon in coal is defined as
That present in volatile matters
The total quantity of carbon present in the coal
Hundred minus the percentage of volatile matter, ash and moisture
The one which is present in the residue after combustion
✅ The correct answer is option C.
83. Which of the following fuels has the highest calorific value per unit mass (kcal/kg)?
Coal
Kerosene
Natural gas
Furnace oil
✅ The correct answer is option D.
84. Which of the following is called “blue gas”?
Coke oven gas
Water gas
Natural gas
Producer gas
✅ The correct answer is option B.
85. Which of the following has the highest gross calorific value?
Blast furnace gas
Coke oven gas
Carburetted water gas
Oil refinery gas
✅ The correct answer is option D.
86. Which of the following is not used as a binder in coal briquetting?
Tar
Molasses
Pitch
Line
✅ The correct answer is option D.
87. Coking time in a commercial high temperature coal carbonisation plant is about __________ hours.
6
18
28
36
✅ The correct answer is option B.
88. In flue gas analysis by Orsat’s apparatus, carbon monoxide is absorbed by
Cuprous chloride
Potassium hydroxide
Alkaline pyrogallol solution
None of these
✅ The correct answer is option A.
89. Washing of coal decreases its
Caking index
Mineral matter content
Ash content
Both B and C
✅ The correct answer is option B.
90. Hard pitch is used for making
Pulverised fuel
Perfumes
Insecticides
Plastics
✅ The correct answer is option A.