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Home Chemical Engineering Fuels and Combustion Comments

  • Question
  • Carbon Content by weight in air dried wood may be about __________ percent.


  • Options
  • A. 10
  • B. 25
  • C. 50
  • D. 80

  • Correct Answer
  • 50 


  • Fuels and Combustion problems


    Search Results


    • 1. Flue gas discharge velocity through chimney of a big thermal power plant may be around __________ m/sec.

    • Options
    • A. 0.5
    • B. 10
    • C. 50
    • D. 500
    • Discuss
    • 2. Which of the following constituents of coal is the most important in the production of coke?

    • Options
    • A. Moisture
    • B. Ash
    • C. Volatiles
    • D. Carbon
    • Discuss
    • 3. Prime coking coal is always blended with medium or non- coking coal before ear-bonisation

    • Options
    • A. to check against its excessive swelling during heating, which may exert high pressure and damage coke oven walls.
    • B. because, it alone produces unreactive coke.
    • C. both (a) and (b).
    • D. neither (a) nor (b).
    • Discuss
    • 4. Bituminous coal

    • Options
    • A. ignites less easily than anthracite.
    • B. is generally coking.
    • C. burns with smoky yellow flame.
    • D. both (b) and (c).
    • Discuss
    • 5. Size of blast furnace grade coke is __________ mm.

    • Options
    • A. 25-80
    • B. 0-15
    • C. 15-25
    • D. >100
    • Discuss
    • 6. Coke oven gas consists mainly of

    • Options
    • A. H2, & CH4
    • B. CO, & CO2
    • C. H2, & CO
    • D. CH4, & CO
    • Discuss
    • 7. During combustion of gaseous fuels, deficiency of air

    • Options
    • A. lengthens the flame.
    • B. tends to shorten the flame.
    • C. does not affect the flame length.
    • D. increases the flame temperature.
    • Discuss
    • 8. Ratio of primary air to secondary air increases with increase in the rank of coal, because the

    • Options
    • A. high rank coals have higher amount of volatile matter.
    • B. ratio of fixed carbon to volatile matter increases.
    • C. oxygen content progressively decreases.
    • D. calorific value of the coal increases.
    • Discuss
    • 9. Overall distillation column efficiency for most of the refinery columns can be given by (for ? = 0.07 - 1.4 cp and relative volatility < 4) (where ? = overall column efficiency, % ? = molal average viscosity of feed at average column temperature and pressure, cp ?p = pressure drop per tray, psi)

    • Options
    • A. ? = 17 - 61.1 log ?
    • B.
    • C. ? = 1.66 - 0.25 log ?
    • D. ? = 0.25 log ? - 1.67
    • Discuss
    • 10. Smaller sized packings are generally dumped to the packed columns, and the large ones of size greater than __________ mm are stacked individually, which provides better control over bed porosity and offers lower gas pressure drop.

    • Options
    • A. 25
    • B. 50
    • C. 75
    • D. 150
    • Discuss


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