Fuels and Combustion
Rate of low temperature oxidation of coal due to bad storage conditions

Is more for low volatile coal compared to high volatile coal
Decreases with increase in surface area
Does not vary with increase in surface area
Is accelerated by storage in large heaps with small surface to volume ratio

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Fuels and Combustion
A liquid/gaseous fuel containing hydrocarbons and high amount of sulphur is burnt with 40% excess air. The flue gas still contains large amount of carbon monoxide. This may be due to the

High sulphur content in the fuel
Lack of thorough mixing of fuel with air
Low calorific value of the fuel
Presence of large quantity of hydrogen in the fuel

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Fuels and Combustion
Presence of free moisture in coal during its high temperature carbonisation

None of these
Reduces the coking time
Protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls
Increases the loss of fine coal dust from the ovens when charging

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