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Home Chemical Engineering Fuels and Combustion Comments

  • Question
  • Calorific value of coal middling generated in coal washeries during washing of coal may be around __________ Kcal/kg.


  • Options
  • A. 1000
  • B. 4000
  • C. 6000
  • D. 8000

  • Correct Answer
  • 4000 


  • Fuels and Combustion problems


    Search Results


    • 1. Natural draught produced by a chimney depends upon the

    • Options
    • A. density of the chimney gases.
    • B. height of the chimney.
    • C. both (a) and (b).
    • D. neither (a) nor (b).
    • Discuss
    • 2. Presence of free moisture in coal during its high temperature carbonisation

    • Options
    • A. reduces the coking time.
    • B. protects the volatile products from pyrolysis (cracking) in the presence of hot coke and hot oven walls.
    • C. increases the loss of fine coal dust from the ovens when charging.
    • D. none of these.
    • Discuss
    • 3. Low temperature carbonisation

    • Options
    • A. is mainly for producing the smokeless domestic coke.
    • B. is meant for the production of 'metallurgical coke'.
    • C. produces higher quantity of gas than high temperature carbonisation.
    • D. produces less quantity of tar than high temperature carbonisation.
    • Discuss
    • 4. The gas which contributes maximum to the heating value of natural gas is

    • Options
    • A. CO
    • B. CO2
    • C. H2
    • D. CH4
    • Discuss
    • 5. Gross and net calorific value of a fuel will be the same

    • Options
    • A. if its ash content is zero.
    • B. ifits carbon content is very low.
    • C. if its hydrogen/hydrogen compound content is zero.
    • D. under no circumstances.
    • Discuss
    • 6. Fuel gases containing hydrocarbons (ie.g. coke oven gas) are not preheated before burning, mainly because

    • Options
    • A. the hydrocarbons crack thereby choking and fouling the heat transfer surface by carbon soot.
    • B. it reduces its calorific value tremendously.
    • C. it reduces its flame temperature tremendously.
    • D. there are chances of explosion during preheating.
    • Discuss
    • 7. Which of the following is the most reactive (as regards the formation of CO + H2 from C + H2O)?

    • Options
    • A. Blast furnace coke
    • B. Low temperature coke
    • C. Anthracite coal
    • D. Sub-bituminous coal
    • Discuss
    • 8. Which of the following is not a product of tar distillation?

    • Options
    • A. Phenol & naphthalene
    • B. Benzol & pitch
    • C. Anthracene & creosote
    • D. None of these
    • Discuss
    • 9. Presence of __________ in a dry gaseous fuel does not contribute to its calorific value.

    • Options
    • A. sulphur
    • B. oxygen
    • C. hydrogen
    • D. carbon
    • Discuss
    • 10. A coal containing very high percentage of durain is called __________ coal.

    • Options
    • A. bright
    • B. splint
    • C. non-banded
    • D. boghead
    • Discuss


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