Fuels and Combustion

291.Pick the odd man out.

1. Briquettes
2. Wood
3. Oil gas
4. Pitch creosote mixture

View answer

292.Pitch creosote mixture (PCM) as compared to furnace oil is a better fuel, because its

1. Emissivity factor is higher
2. Sulphur content is lower
3. Flue gas has lower dew point thereby facilitating more waste heat recovery
4. All (A), (B) and (C)

View answer

293.Power alcohol as compared to straight run gasoline has lower

1. Calorific value
2. Octane number
3. Specific gravity
4. Viscosity

View answer

294.Preheating of _________ the flame temperature.

1. The gaseous fuel before combustion decreases
2. Combustion air decreases
3. Either the fuel or the air or both, increases
4. Either the fuel or the air does not affect

View answer

295.Preheating of a gaseous fuel results in increased

1. Flame length
2. Flame temperature
3. Quantity of flue gas
4. Ignition temperature

View answer

296.Preheating of coal charge for the coke ovens reduces the

1. Time of carbonisation
2. Yield of gas and tar
3. Fuel consumption in coking
4. All (A), (B) and (C)

View answer

297.Preheating of combustion air is done to

1. Increase the adiabatic flame temperature
2. Increase the calorific value of the fuel
3. Complete the combustion of fuel
4. Reduce its requirement for effecting the complete combustion

View answer

298.Presence of _________ in a dry gaseous fuel does not contribute to its calorific value.

1. Sulphur
2. Oxygen
3. Hydrogen
4. Carbon

View answer

299.Presence of force moisture in coal is most disadvantageous during its

1. Transportation and handling
2. Washing
3. Pulverisation
4. Storage

View answer

300.Presence of free moisture in coal during its high temperature carbonisation

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

View answer