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Chemical Engineering :: Fuels and Combustion

  1. Pick out the wrong statement.

  2. A.
    Cokes of high reactivity are obtained from weakly coking coals.
    B.
    Cokes of high reactivity are obtained from strongly coking coals.
    C.
    Reactivity of coke is inversely proportional to its absolute density.
    D.
    Abrasion index of the coke is a measure of its hardness.

  3. Which of the following has the highest gross calorific value ?

  4. A.
    Blast furnace gas
    B.
    Coke oven gas
    C.
    Carburetted water gas
    D.
    Oil refinery gas

  5. 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

  6. A.
    presence of large quantity of hydrogen in the fuel.
    B.
    low calorific value of the fuel.
    C.
    high sulphur content in the fuel.
    D.
    lack of thorough mixing of fuel with air.

  7. Efficient burning of anthracite coal requires

  8. A.
    low preheat of air.
    B.
    fine grinding.
    C.
    high excess air.
    D.
    all (a), (b) and (c).

  9. C/H ratio is the minimum in case of

  10. A.
    furnace oil
    B.
    natural gas
    C.
    coal
    D.
    naphtha

  11. Naphthalene is used for making

  12. A.
    insecticides (e.g. moth balls).
    B.
    unsaturated polyesters.
    C.
    drug intermediates e.g. β-naphthol.
    D.
    all (a), (b) and (c).

  13. The advantage of firing pulverised coal in the furnace lies in the fact, that it

  14. A.
    permits the use of high ash content coal.
    B.
    permits the use of low fusion point ash coal.
    C.
    accelerates the burning rate and economises on fuel combustion.
    D.
    all (a), (b) and (c).

  15. A coal having higher volatile matter content, has lower

  16. A.
    smoking tendency on burning.
    B.
    coke oven gas yield on carbonisation.
    C.
    chance of catching fire during storage in open space.
    D.
    ignition temperature.

  17. Weathering of coal during storage causes

  18. A.
    reduction in coal size.
    B.
    increase in its friability.
    C.
    decrease in its caking capacity.
    D.
    all (a), (b) and (c).

  19. With increase in the temperature of carbonisation of coal

  20. A.
    hydrogen content of coke oven gas increases due to cracking of hydrocarbons.
    B.
    methane content in the coke oven gas decreases and carbon monoxide content increases.
    C.
    calorific value of the coke oven gas decreases due to cracking of hydrocarbons which is not compensated by increase in CO & H2 content.
    D.
    all (a), (b) and (c)