Chemical Engineering - Fuels and Combustion

16. 

"Overfire burning" in a furnace is a phenomenon characterised by the

A. supply of excess fuel.
B. supply of excess air.
C. burning of carbon monoxide and other incombustibles in upper zone of furnace by supplying more air.
D. none of these.

Answer: Option C

Explanation:

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17. 

Yield of pitch from distillation of high temperature tar is around __________ percent.

A. 10
B. 25
C. 65
D. 90

Answer: Option C

Explanation:

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18. 

Fuel consumption in coke making can be reduced by

A. preheating, blending and de-ashing the coal.
B. stamped charging of coal.
C. dry quenching of coke.
D. all (a), (b) and (c).

Answer: Option D

Explanation:

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19. 

During combustion of coal on grate, clinker formation is increased by the

A. use of thick fire bed.
B. low fusion point of ash (< 1100° C).
C. use of preheated primary air.
D. all (a), (b) & (c).

Answer: Option D

Explanation:

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20. 

If the specific heat of gaseous products of combustion of a fuel is high, the abiabatic flame temperature will be

A. low
B. high
C. very high, if the fuel is of low calorific value
D. none of these

Answer: Option A

Explanation:

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