chemical engineering fuels and combustion MCQs – Page 4

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 Review each marked answer and report any item that may be outdated or unclear.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
61. Low temperature oxidation of stored coal results in the________________?
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A. All A., B. and A.

B. Decrease in its carbon & hydrogen content

C. Increase in its oxygen content

D. Decrease in its caking power & calorific value

62. Lurgi coal gasifier is a pressurised ______________ bed reactor?
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A. Moving

B. Fixed

C. Entrained

D. Fluidised

63. A coal gasifier operating at 20 atm. (e.g. Lurgi gasifier) as compared to one operating at atmospheric pressure (e.g. Kopper-Totzek or Winkler gasifier) will produce a gas having _____________________?
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A. Higher carbon monoxide content

B. Lower carbon dioxide content

C. None of these

D. Higher methane content and thus higher calorific value
64. Wind loss resulting from unscientific storage of coal may be the order of about _____________ percent?
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A. 7.5

B. 10.5

C. 14.5

D. 2.5
65. Which of the following accentuates clinkering trouble on furnace grate burning coal ?
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A. Thick fire bed and preheated primary air

B. All A., B. and C.

C. Low reactivity of carbonised residue containing high proportions of iron & sulphur

D. Low forced draught and fuel bed temperature

66. Blast furnace gas compared to coke oven gas has_________________?
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A. Narrower limit of inflammability

B. Lower ignition temperature

C. Higher calorific value

D. Lower theoretical flame temperature
67. Orsat apparatus__________________?
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A. Cant determine CO in flue gas, if it is < 0.2%

B. Gives flue gas analysis on dry basis

C. All A., B. & C.

D. Determines N2 in flue gas indirectly

68. Calorific value of tar is about _____________ Kcal/kg?
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A. 14000

B. 12000

C. 16000

D. 8800
69. For every 10% increase in the excess air; the fuel consumption increases by _______________ percent?
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A. 0.5

B. 1

C. 0.2

D. 0.1
70. The calorific value of a gas of composition CO2 = 20%, H2 = 50%, CH4 = 30%, is y. If the composition of gas is changed to H2 = 50%, CH4 = 30%, CO2 = 10%, N2 = 10%, then the calorific value will be___________________?
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A. y

B. 1.05 y

C. 0.95 y

D. 1.8 y

71. In flue gas analysis by Orsats apparatus, carbon monoxide is absorbed by__________________?
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A. None of these

B. Alkaline pyrogallol solution

C. Potassium hydroxide

D. Cuprous chloride
72. ombustion of pulverised coal compared to the lumpy coal __________________?
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A. Provides higher thermal efficiency & flame temperature

B. Facilitates combustion with lower excess air

C. Provides better control of furnace temperature

D. All A., B. & C.
73. _____________ of the coal is the basis for Seylors coal classification?
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A. Ultimate analysis

B. Proximate analysis

C. Calorific value

D. Caking index

74. Tar is a better fuel than furnace oil, because of its___________________?
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A. Higher calorific value

B. Lower sulphur content

C. Higher emissivity (0.8-0.9) resulting in higher radiation heat transfer rate

D. Both A. and B.
75. Low temperature oxidation of coal during storage does not decrease its__________________?
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A. Calorific value

B. Caking power

C. None of these

D. Oxygen content

76. Main constituent of the gas produced from a gobar gas plant is___________________?
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A. CH4

B. CO2

C. CO

D. H2

77. Which of the following petrographic constituents of coal is non-coking ?
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A. Fussain

B. Vitrain

C. Clarain

D. Durain

78. Dust content in raw blast furnace gas is about _______________ gm/Nm3; hence it is cleaned to the dust level of about < 10 mg /Nm3 before use?
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A. 150-200

B. 70-100

C. 2-Jan

D. 15-30
79. High excess air in combustion of fuels results in____________________?
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A. Incomplete combustion

B. None of these

C. Increased fuel consumption

D. Smoky flame

80. Purity of coke means that, it is high in carbon and low in __________________?
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A. Volatiles

B. Iron

C. Moisture

D. Ash