Fuels and Combustion pdf Chemical Engg. Questions - Set 03 - ObjectiveBooks

Fuels and Combustion pdf Chemical Engg. Questions - Set 03

Practice Test: Question Set - 03

1. Caking index of coal blend used for blast furnace coke making is about
    (A) 8
    (B) 12
    (C) 22
    (D) 36

2. The main drawback of supplying more excess air in the combustion of fuel is the
    (A) Excessive power requirement of air blower
    (B) Enhanced sensible heat loss in the flue gas
    (C) Intermittent and uncontrolled combustion of the fuel
    (D) High exit flue gas temperature from the furnace

3. Calorific value of coke oven gas is around __________ Kcal/Nm3.
    (A) 900
    (B) 4200
    (C) 7500
    (D) 2000

4. The maximum adiabatic flame temperature in air is __________ the maximum flame temperature in pure oxygen.
    (A) Lower than
    (B) Higher than
    (C) Same as
    (D) Not related to

5. Fusion point of coal ash increases with increase in its __________ content.
    (A) Iron sulphate
    (B) Iron silicate
    (C) Lime and magnesia
    (D) All (a), (b) and (c)

6. Largest constituent of coke oven gas is
    (A) N2
    (B) H2
    (C) CH4
    (D) CO2

7. Sulphur in metallurgical coal
    (A) Contributes to its heating value
    (B) Affects the quality of steel produced as cracks develop on the surface while rolling the steel
    (C) Both (a) and (b)
    (D) Neither (a) nor (b)

8. Bomb calorimeter can be used to determine the __________ of the coal.
    (A) Sulphur content
    (B) Calorific value
    (C) Both (a) & (b)
    (D) Neither (a) nor (b)

9. Which of the following is not a by-product fuel?
    (A) Sewage gas
    (B) Refinery gas
    (C) Producer gas
    (D) Bagasse

10. A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be
    (A) More
    (B) Less
    (C) Same
    (D) Data insufficient; can't be predicted

11. Oxygen content in a flue gas was found to be 4%. It implies that excess air used for combustion was around __________ percent.
    (A) 4
    (B) 96
    (C) 20
    (D) 40

12. Combustion reaction of fuels is a/an __________ reaction.
    (A) Auto catalytic
    (B) Exothermic
    (C) Endothermic
    (D) None of these

13. Gasification of the solid fuel converts its organic part into combustible by interaction with air/oxygen and steam so as to obtain a secondary gaseous fuel of high calorific value having no ash. Gasification reactions are normally carried out at about __________ °C.
    (A) 400-500
    (B) 900-1000
    (C) 1400-1500
    (D) 1700-1800

14. A coal having high volatile matter content will
    (A) Give less yield of tar and gas on carbonization
    (B) Burn with a small non-smoky flame
    (C) Have a very high calorific value
    (D) None of these

15. Oxygen percentage (by weight) in atmospheric air is
    (A) 19
    (B) 21
    (C) 23
    (D) 29

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