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chemical engineering fuels and combustion MCQs

Practise multiple-choice questions from chemical engineering fuels and combustion for competitive examinations and subject revision. Review each marked answer and report any item that may be outdated or unclear.

chemical engineering fuels and combustion Mcqs
1. Which is the heaviest fuel gas out of the following ?
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A. Blast furnace gas

B. Water gas

C. Carburetted water gas

D. Coke oven gas

2. Tar yield in the low temperature and high temperature carbonisation of dry coal may be respectively ______________ percent?
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A. 15 & 8

B. 10 & 3

C. 3 & 10

D. 10 & 20

3. Nitrogen in coal_________________?
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A. Is present upto 1-2%

B. All A., B. and C.

C. Is recovered as ammonia during its carbonisation

D. Comes from protein in parent vegetable matter

4. Highly caking coals_____________________?
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A. Produce weak coke

B. Produce strong coke

C. May damage the coke oven walls during carbonisation

D. Both B. and C.
5. Number of macrocomponents present in coal according to Stopes are ___________________?
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A. Two

B. Four

C. Six

D. Five

6. Incomplete combustion of a fuel is characterised by the high _______________ in the flue gas?
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A. Smoke

B. Oxygen

C. Carbon monoxide

D. Temperature

7. Which of the following is not a by-product fuel ?
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A. Pitch

B. Refinery gas

C. Blast furnace gas

D. Petrol
8. Presence of nitrogen in combustion air does not reduce the ____________________?
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A. Any of the above

B. Flue gas temperature

C. Flame temperature

D. Amount of heat liberated
9. Which of the following is the most poisonous gas ?
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A. Coke oven gas

B. Producer gas

C. Blast furnace gas

D. L.D. converter gas
10. Shatter index of the coke is a measure of its___________________?
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A. Bulk density

B. Reactivity

C. Strength
11. Coals used for the generation of producer gas should have ____________________?
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A. Low fusion point of ash

B. High caking index

C. Very low ash content (8-10%)

D. High volatile matter content
12. Volatile matter content in coking coal may be about _____________ percent?
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A. 7

B. 22

C. 46

D. 1

13. Which of the following will be unsuitable for dust cleaning from flue gas at 400C from a pulverised coal fired boiler ?
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A. Wet scrubber

B. Hydrocyclones

C. Bag filter

D. Multicyclones

14. The calorific value of L.D. converter gas is about ____________ Kcal/Nm3?
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A. 1800

B. 800

C. 4500

D. 10000

15. The average molecular weight of a flue gas having the composition by volume as CO2 = 25%, O2 = 25%, N2 = 50% will be___________________?
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A. 27.6

B. 47.3

C. 23

D. 42.9

16. Caking coal is desirable for_________________?
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A. Burning on travelling grate

B. All A., B. and C.

C. Coke making

D. Burning on firebars

17. With increase in moisture content of coal, its_____________________?
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A. Bulk density always decreases

B. Clinkering tendency during combustion increases

C. Calorific value increases sometimes

D. None of these
18. The calorific value of producer gas is around _____________ kcal/Nm3?
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A. 1300

B. 9000

C. 4500

D. 500

19. Fat coals are those coals which have very high____________________?
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A. Inherent moisture content

B. Volatile matter content

C. Caking capacity

D. Fusion point of its ash

20. Which of the following would require least amount of secondary air for combustion ?
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A. Anthracite containing 10% volatile matter and 8% ash

B. Semi-bituminous coal containing 25% ash and 20% volatile matter

C. Coke breeze containing 25% ash and 2% volatile matter

D. Bituminous coal containing 20% ash and 25% volatile matter

21. Which of the following is unsuitable fuel for producer gas manufacture ?
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A. Coal having low fusion point of its ash

B. Anthracite

C. Coke

D. Coal having high fusion point of its ash

22. The hottest part of the flame lies in its _______________ zone?
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A. Non-luminous

B. Unburnt gases

C. Yellow

D. Luminous

23. The reaction, C + CO2 ? 2CO, taking place during coal gasification is called the ______________ reaction?
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A. Shift conversion

B. Boudouard

C. Reduction

D. Neumann reversal

24. Percentage of carbon monoxide in blast furnace gas may be around ____________________ ?
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A. 8

B. 22

C. 14

D. 52

25. In general, the limit of inflammability/explosion limit of fuel gases is widened by the__________________?
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A. Use of pure oxygen for combustion instead of air

B. Increase in gas pressure

C. All A., B. & C.

D. Increase in temperature (i.e. preheating)

26. Bunsen burner is an example of a/an _____________ burner?
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A. Inside mixing/premix type

B. Rotary cup

C. Submerged combustion

D. Outside mixing/diffusion flame/nozzle mix type

27. The cooling medium used in dry quenching of coke is___________________?
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A. Air

B. Phenolic water

C. Nitrogen

D. Carbon dioxide

28. Coke ovens in steel plant are heated by ___________________?
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A. Electricity

B. Coke oven gas

C. Mixed gas

D. Both B. & C.
29. The maximum adiabatic flame temperature in air is _____________ the maximum flame temperature in pure oxygen?
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A. Higher than

B. Not related to

C. Lower than

D. Same as

30. Use of pulverised coal in boiler furnace provides___________________?
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A. High calorific value

B. Less erosion on furnace walls

C. Smokeless burning

D. Better combustion
31. Fuel for a nuclear reactor (thermal) is ____________________?
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A. Uranium

B. Plutonium

C. None of these

D. Radium

32. Rate of low temperature oxidation of coal due to bad storage conditions_______________?
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A. Is accelerated by storage in large heaps with small surface to volume ratio

B. Is more for low volatile coal compared to high volatile coal

C. Does not vary with increase in surface area

D. Decreases with increase in surface area

33. A good metallurgical coke___________________?
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A. Must contain moderate quantities of ash, moisture, sulphur and volatile matters

B. Should have low fusion point of its ash

C. Should have high porosity

D. Should be brittle

34. Flue gas obtained on complete combustion of pure acetylene (a hydrocarbon fuel) will contain __________________?
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A. CO

B. CO2

C. H2O

D. Both B. & C.
35. Which of the following has the highest calorific value ?
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A. Sub-bituminous coal

B. Peat

C. Anthracite

D. Lignite

36. Percentage of methane in coke oven gas may be around _____________________?
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A. 5

B. 50

C. 25

D. 15

37. A coal with high ash content is undesirable, as________________?
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A. causes its spalling due to different co-efficient of expansion/contraction of the refractory

B. boiler tubes thereby reducing the heat transfer

C. It is abrasive to the coal pulveriser (i.e. ball mill) and the combustion chamber

D. The ash in molten condition gets absorbed in the pores of the refractory lining of the furnace

E. All A., B. and C.

F. the ash

38. The catalyst used in shift converter is _____________________?
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A. Alumina

B. Silica gel

C. Vanadium

D. Nickel
39. Short/intense flame is produced during combustion of gaseous fuel by using________________?
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A. High amount/current of combustion air

B. Very little excess air

C. Preheated secondary air

D. Low amount/current of combustion air

40. Calorific value of blast furnace gas is around _____________ KCal/Nm3?
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A. 6500

B. 850

C. 4200

D. 1800

41. Mott and Wheeler test is conducted on coke to find its _____________________?
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A. Volatile matter content

B. Reactivity with O2

C. Abradability

D. Phosphorus content

42. Soft coke is not ___________________?
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A. Used in blast furnaces

B. Produced by low temperature carbonisation of coal

C. None of these

D. A domestic fuel

43. Which of the following has the highest theoretical flame temperature ?
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A. Blast furnace gas

B. Coke oven gas

C. Acetylene

D. Hydrogen

44. Caking index of a coal is a measure of its _______________________?
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A. Agglutinating (binding) properties

B. Reactivity

C. Abradability

D. Porosity

45. A coal having higher volatile matter content, has lower_________________?
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A. Smoking tendency on burning

B. Chance of catching fire during storage in open space

C. Coke oven gas yield on carbonisation

D. Ignition temperature
46. Coke oven gas is stripped of its H2S and mercaptans content by_________________?
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A. Adsorption on bog iron bed

B. Bubbling it through dilute sulphuric acid

C. Adsorption on silica gel

D. Absorption in wash oil

47. When steam is passed over coal resulting in the endothermic reaction represent by, C + H2O = CO + H2, it is called the _______________ of coal?
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A. Oxidation

B. Gasification

C. Carbonisation

D. Coalification

48. Increase in ash content of blast furnace coke_________________?
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A. Reduces its consumption in the furnace

B. Decreases its hardness and abrasion resistance

C. Does not affect its consumption in the furnace

D. Increases its consumption in the furnace
49. Very ______________ coals are completely devoid of cokability i.e., it is non-coking ?
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A. Young

B. Mature

C. Both A & B

D. Neither A nor B

50. A coal having high volatile matter content will ________________?
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A. None of these

B. Give less yield of tar and gas on carbonisation

C. Have a very high calorific value

D. Burn with a small non-smoky flame