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Chemical Engineering :: Fuels and Combustion

  1. Which of the following is not increased by using preheated combustion air in place of ordinary air at room temperature ?

  2. A.
    Calorific value of the fuel.
    B.
    Flame temperature achieved.
    C.
    Speed of combustion of fuel.
    D.
    Heat transfer rate to the stock in the furnace.

  3. Wood charcoal is obtained by the destructive distillation of wood. It is used in the production of activated carbon, which is not used for the

  4. A.
    decolourisation of sugar.
    B.
    solvent recovery from air and gases
    C.
    absorption of gases and vapor.
    D.
    electrode manufacture.

  5. Washing of coal is done to reduce the

  6. A.
    inherent impurities
    B.
    adhering impurities
    C.
    mineral matter
    D.
    both (b) and (c)

  7. Volumetric ratio of N2 to O2 in dry atmospheric air is

  8. A.
    0.21
    B.
    3.76
    C.
    4.76
    D.
    0.79

  9. Coke oven gas burns with an yellowish flame, because of the presence of

  10. A.
    CO2
    B.
    CH4
    C.
    H2
    D.
    NH3

  11. Calorific value of

  12. A.
    light paraffinic fuel oils is equal to that of equivalent olefins.
    B.
    n-paraffin is lower than that of iso-paraffins of the same compounds.
    C.
    light paraffinic fuel oils is higher than that of equivalent olefins.
    D.
    light paraffinic fuel oils is lower than that of equivalent olefins.

  13. Which of the following would require least amount of secondary air for combustion ?

  14. A.
    Coke breeze containing 25% ash and 2% volatile matter.
    B.
    Anthracite containing 10% volatile matter and 8% ash.
    C.
    Bituminous coal containing 20% ash and 25% volatile matter.
    D.
    Semi-bituminous coal containing 25% ash and 20% volatile matter.

  15. 'Fat coals' are those coals which have very high

  16. A.
    caking capacity.
    B.
    volatile matter content.
    C.
    fusion point of its ash.
    D.
    inherent moisture content.

  17. Highly reactive coke have lower

  18. A.
    porosity.
    B.
    coke reactivity index (CRI).
    C.
    Critical air blast (CAB) value.
    D.
    both (b) and (c).

  19. A coal with high ash content

  20. A.
    has higher calorific value.
    B.
    is harder and stronger.
    C.
    is not subjected to washing.
    D.
    has low quantity of mineral matter.