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Chemical Engineering :: Fuels and Combustion

  1. The calorific value of natural gas is about __________ kcal/Nm3.

  2. A.
    10, 000
    B.
    2500
    C.
    25, 000
    D.
    35, 000

  3. Low temperature carbonisation of coal takes place at __________ °C.

  4. A.
    300
    B.
    1100
    C.
    700
    D.
    150

  5. Critical Air Blast (CAB) value of coke is a direct measure of its

  6. A.
    reactivity
    B.
    hardness
    C.
    strength
    D.
    none of these

  7. The function of secondary combustion air is to

  8. A.
    pneumatically convey the pulverised coal.
    B.
    completely burn the volatile matter.
    C.
    burn the lumpy coal.
    D.
    none of these.

  9. The ratio of maximum adiabatic flame temperature in air to that in pure oxygen is always

  10. A.
    1
    B.
    <1
    C.
    > 1
    D.
    unpredicatable

  11. Fixed carbon in coal is defined as

  12. A.
    that present in volatile matters.
    B.
    the total quantity of carbon present in the coal.
    C.
    hundred minus the percentage of volatile matter, ash and moisture.
    D.
    the one which is present in the residue after combustion.

  13. Which of the following fuels has the highest calorific value per unit mass (kcal/kg) ?

  14. A.
    Coal
    B.
    Kerosene
    C.
    Natural gas
    D.
    Furnace oil

  15. With increase in the time of carbonisation at a particular temperature (say 1000°C), the __________ percentage in coke oven gas increases.

  16. A.
    hydrogen
    B.
    methane
    C.
    unsaturated hydrocarbons
    D.
    all (a), (b) and (c)

  17. During its calorific value determination by bomb calorimeter, coal is combusted by

  18. A.
    air
    B.
    oxygen
    C.
    oxygen enriched air
    D.
    none of these

  19. Abel apparatus is used for those oils, whose flash points are___°F.

  20. A.
    <120
    B.
    >120
    C.
    >280
    D.
    300-600