Combustion and Fossil Fuels Multiple Choice Questions - Set 21 - ObjectiveBooks

Combustion and Fossil Fuels Multiple Choice Questions - Set 21

Practice Test: Question Set - 21


1. With increase in moisture content of coal, its
    (A) Calorific value increases sometimes
    (B) Bulk density always decreases
    (C) Clinkering tendency during combustion increases
    (D) None of these

2. With increase in the time of carbonization at a particular temperature (say 1000°C), the __________ percentage in coke oven gas increases.
    (A) Hydrogen
    (B) Methane
    (C) Unsaturated hydrocarbons
    (D) All (a), (b) and (c)

3. Which of the following has the highest gross calorific value?
    (A) Blast furnace gas
    (B) Coke oven gas
    (C) Carburetted water gas
    (D) Oil refinery gas

4. Preheating of __________ the flame temperature.
    (A) The gaseous fuel before combustion decreases
    (B) Combustion air decreases
    (C) Either the fuel or the air or both, increases
    (D) Either the fuel or the air does not affect

5. Which of the following is not a 'manufactured' fuel?
    (A) LPG
    (B) Coal briquettes
    (C) Tar
    (D) Colloidal fuels

6. As the C/H ratio of the fuel increases, the amount of CO2 formed on combustion __________ for the same percentage of excess air.
    (A) Decreases
    (B) Increases
    (C) Remain same
    (D) May increase or decrease depending on the type of fuel

7. Purity of coke means that, it is high in carbon and low in
    (A) Volatiles
    (B) Ash
    (C) Iron
    (D) Moisture

8. Low temperature oxidation of coal is accelerated by the
    (A) Storage in large heaps
    (B) Storage in compressed piles
    (C) Absence of porous or friable particles
    (D) All (a), (b) and (c)

9. Coke oven gas produced by high temperature carbonization of coal (as compared to that produced by low temperature carbonization), has
    (A) Higher calorific value
    (B) Lower hydrogen content
    (C) Both (a) and (b)
    (D) Neither (a) nor (b)

10. Which of the following is a measure of the agglutinating (i.e., binding) property of coal?
    (A) Thickness of plastic layer
    (B) Caking index
    (C) Swelling index
    (D) Gray-king index

11. Natural draft created by the chimney depends upon
    (A) Temperature of the flue gas
    (B) Its height
    (C) Both (a) & (b)
    (D) Neither (a) nor (b)

12. By-products recovery process from coal carbonization is termed as direct, indirect and semi direct process depending upon the method of recovery of
    (A) Tar
    (B) Benzol
    (C) Ammonia
    (D) None of these

13. Coke oven gas constitutes mainly of
    (A) H2 & CO
    (B) H2 & CH4
    (C) CH4 & CO
    (D) H2 & CO2

14. Shatter index of metallurgical coke on 2 inches and 0.5 inch screen should be respectively around __________ percent.
    (A) 80 and 97
    (B) 95 and 100
    (C) 40 and 70
    (D) 25 and 97

15. Presence of nitrogen in combustion air does not reduce the
    (A) Amount of heat liberated
    (B) Flame temperature
    (C) Flue gas temperature
    (D) Any of the above

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