Fuels and Combustion

121.Coke ovens in steel plant are heated by

1. Electricity
2. Coke oven gas
3. Mixed gas
4. Both (B) & (C)

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122.Coking coals are invariably

1. Lignites
2. Bituminous coals
3. Semi-anthracites
4. Anthracites

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123.Coking time in a commercial high temperature coal carbonisation plant is about _________ hours.

1. 6
2. 18
3. 28
4. 36

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124.Coking time in beehive coke oven is about

1. 12 hours
2. 2-3 days
3. One week
4. Two weeks

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125.Coking time in narrow by-product coke ovens is around _________ hours.

1. 18
2. 48
3. 8
4. 80

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126.Combustion of pulverised coal as compared to that of lump coal

1. Develops a non-luminous flame
2. Develops a low temperature flame
3. Can be done with less excess air
4. Provides a lower rate of heat release

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127.Combustion of pulverised coal compared to the lumpy coal

1. Provides better control of furnace temperature
2. Facilitates combustion with lower excess air
3. Provides higher thermal efficiency & flame temperature
4. All (A), (B) & (C)

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128.Combustion reaction of fuels is a/an _________ reaction.

1. Auto catalytic
2. Exothermic
3. Endothermic
4. None of these

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129.Commercial production of petrol from coal (as practised in a factory at Sasol in South Africa) is done by the _________ of coal.

1. Hydrogenation
2. Gasification
3. Carbonisation
4. None of these

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130.Compound coke ovens are those which can be heated by

1. Both steam and electrical power
2. Lean gas (e.g., B.F. gas)
3. Rich gas (e.g., coke oven gas)
4. Both (B) and (C)

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