E-PolyLearning

1. Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because
a. the hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot.
b. it reduces its calorific value tremendously.
c. it reduces its flame temperature tremendously.
d. there are chances of explosion during preheating.
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Answer: (a).the hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot.

2. Which of the following is the most reactive (as regards the formation of CO + H₂ from C + H₂O) ?
a. Blast furnace coke
b. Low temperature coke
c. Anthracite coal
d. Sub-bituminous coal
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Answer: (b).Low temperature coke

3. Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.
a. 1000
b. 4000
c. 6000
d. 8000
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Answer: (b).4000

4. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.
a. 0.5
b. 10
c. 50
d. 500
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Answer: (b).10

5. Which of the following is used for making the explosive 'TNT' ?
a. Benzol
b. Toluene
c. Pyridine
d. Cerosote
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Answer: (b).Toluene

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