Chemical Engineering - Fuels and Combustion

31. 

Presence of free moisture in coal is most disadvantageous during

A. its pulverisation (as it requires more power).
B. combustion of fire slacks on the grates.
C. handling (e.g. when emptying wagons).
D. none of these.

Answer: Option A

Explanation:

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32. 

The heat of combustion of a fuel

A. is equal to the heat of formation.
B. is always negative.
C. can't be known without calculating it.
D. is always positive.

Answer: Option B

Explanation:

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33. 

High excess air in combustion of fuels results in

A. increased fuel consumption
B. incomplete combustion
C. smoky flame
D. none of these

Answer: Option A

Explanation:

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34. 

Abrasion index of blast furnace coke should be around __________ percent.

A. 20
B. 35
C. 55
D. 80

Answer: Option D

Explanation:

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35. 

Tar yield in the low temperature and high temperature carbonisation of dry coal may be respectively __________ percent.

A. 3 & 10
B. 10 & 3
C. 10 & 20
D. 15 & 8

Answer: Option B

Explanation:

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