Froth floatation is used for

Fuels and Combustion
Froth floatation is used for

Washing fine coal dust (< 0.5 mm size)

All of these

Removing ash from the coal based on difference in specific gravity of coal and ash

Washing lump coal (> 80 mm size)

Washing fine coal dust (< 0.5 mm size)

All of these

Removing ash from the coal based on difference in specific gravity of coal and ash

Washing lump coal (> 80 mm size)

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Fuels and Combustion
Which of the following is the most reactive (as regards the formation of CO + H₂ from C + H₂O) ?

Sub-bituminous coal

Anthracite coal

Low temperature coke

Blast furnace coke

Sub-bituminous coal

Anthracite coal

Low temperature coke

Blast furnace coke

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Fuels and Combustion
Nitrogen in coal

Comes from protein in parent vegetable matter

Is recovered as ammonia during its carbonisation

All of these

Is present upto 1-2%

Comes from protein in parent vegetable matter

Is recovered as ammonia during its carbonisation

All of these

Is present upto 1-2%

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Fuels and Combustion
A coal with high ash content is undesirable, as

The ash in molten condition gets absorbed in the pores of the refractory lining of the furnace and causes its spalling due to different co-efficient of expansion/contraction of the refractory and the

The ash retains the sulphur & phosphorus and thus affects the quality of products in metallurgical furnace apart from increasing the slag volume. Besides, it may fuse and stick to the boiler tubes

It is abrasive to the coal pulveriser (ie.g. ball mill) and the combustion chamber

All of these

The ash in molten condition gets absorbed in the pores of the refractory lining of the furnace and causes its spalling due to different co-efficient of expansion/contraction of the refractory and the

The ash retains the sulphur & phosphorus and thus affects the quality of products in metallurgical furnace apart from increasing the slag volume. Besides, it may fuse and stick to the boiler tubes

It is abrasive to the coal pulveriser (ie.g. ball mill) and the combustion chamber

All of these

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Fuels and Combustion
Presence of nitrogen in combustion air does not reduce the

Flame temperature

Amount of heat liberated

Any of the above

Flue gas temperature

Flame temperature

Amount of heat liberated

Any of the above

Flue gas temperature

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Fuels and Combustion
The average molecular weight of a flue gas having the composition by volume as CO₂ = 25%, O₂ = 25%, N₂ = 50% will be

23

42.9

27.6

47.3

23

42.9

27.6

47.3

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Fuels and Combustion

Fuels and Combustion Froth floatation is used for

Fuels and Combustion Which of the following is the most reactive (as regards the formation of CO + H₂ from C + H₂O) ?

Fuels and Combustion Nitrogen in coal

Fuels and Combustion A coal with high ash content is undesirable, as

Fuels and Combustion Presence of nitrogen in combustion air does not reduce the

Fuels and Combustion The average molecular weight of a flue gas having the composition by volume as CO₂ = 25%, O₂ = 25%, N₂ = 50% will be

Fuels and Combustion
Froth floatation is used for

Fuels and Combustion
Which of the following is the most reactive (as regards the formation of CO + H₂ from C + H₂O) ?

Fuels and Combustion
Nitrogen in coal

Fuels and Combustion
A coal with high ash content is undesirable, as

Fuels and Combustion
Presence of nitrogen in combustion air does not reduce the

Fuels and Combustion
The average molecular weight of a flue gas having the composition by volume as CO₂ = 25%, O₂ = 25%, N₂ = 50% will be