Fuel Combustion and Gasification Questions Answers - Set 11 - ObjectiveBooks

Fuel Combustion and Gasification Questions Answers - Set 11

Practice Test: Question Set - 11

1. In general, the limit of inflammability/explosion limit of fuel gases is widened by the
    (A) Increase in gas pressure
    (B) Increase in temperature (i.e. preheating)
    (C) Use of pure oxygen for combustion instead of air
    (D) All (a), (b) & (c)

2. During the carbonization of coal
    (A) All tar is evolved at < 600°C
    (B) Evolution of H2 and formation of methane and aromatics occur at > 700°C
    (C) Hard semi-coke starts shrinking at 600°C
    (D) All (a), (b) and (c)

3. With increase in moisture content of coal, its
    (A) Calorific value increases
    (B) Caking properties diminish
    (C) Swelling during carbonization becomes excessive
    (D) None of these

4. Which of the following coal gasification processes will produce gas having maximum methane content?
    (A) Winkler process
    (B) Lurgi process
    (C) Kopper-Totzek process
    (D) All can produce same methane content

5. Coke oven gas burns with a yellowish flame, because of the presence of
    (A) CO2
    (B) CH4
    (C) H2
    (D) NH3

6. Gobar (cow dung) gas constitutes mainly of
    (A) CH4 & CO2
    (B) CO & CO2
    (C) CH4 & N2
    (D) CO & N2

7. Correct viscosity of furnace oil at the burner tip for proper atomization is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomization viscosity (i.e. 25 cst), it should be preheated to about ___________°C.
    (A) 70
    (B) 85
    (C) 105
    (D) 145

8. While the first commercial low temperature coal carbonization plant is located at Neyveli (in Chennai, India), the second such plant has been built at
    (A) Dankuni (West Bengal)
    (B) Dhanbad
    (C) Singreni (AP.)
    (D) Raniganj

9. Supply of excess air for complete combustion of fuel is necessitated to facilitate
    (A) Its thorough mixing with air
    (B) Attainment of chemical equilibrium
    (C) Attainment of high temperature
    (D) None of these

10. High temperature carbonization of coal produces
    (A) Inferior coke compared to low temperature carbonization
    (B) Less of gases compared to liquid products
    (C) Large quantity of tar compared to low temperature carbonization
    (D) None of these

11. Combustion of pulverized coal compared to the lumpy coal
    (A) Provides better control of furnace temperature
    (B) Facilitates combustion with lower excess air
    (C) Provides higher thermal efficiency & flame temperature
    (D) All (a), (b) & (c)

12. Which of the following constituents of a fuel does not contribute to its calorific value on combustion?
    (A) Hydrogen
    (B) Sulphur
    (C) Carbon
    (D) None of these

13. High rate of heating of coke ovens
    (A) May damage its walls due to abrupt excessive swelling of coal
    (B) Produces larger size coke
    (C) Increases the time of carbonization
    (D) None of these

14. Benzene is used
    (A) As a motor fuel
    (B) As an explosive
    (C) For making insecticides (e.g., DDT, BHC etc.), detergent & rubber (SBR)
    (D) As a perfume

15. Low temperature oxidation of stored coal results in the
    (A) Decrease in its caking power & calorific value
    (B) Decrease in its carbon & hydrogen content
    (C) Increase in its oxygen content
    (D) All (a), (b) and (c)

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