chemical engineering fuels and combustion Mcqs
51. Which of the following is not endothermic ?
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A. Reforming

B. Gasification

C. Cracking

D. Partial oxidation
52. Hardgrove Grindability index of four coal samples are given below. Which of them is the easiest to grind ?
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A. 100

B. 70

C. 50

D. 85

53. The gasification reaction represented by, C + H2O = CO + H2, is__________________?
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A. Exothermic

B. Autocatalytic

C. Catalytic

D. Endothermic
54. Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher __________________?
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A. Difference in gross & net calorific value

B. Sulphur content

C. Higher C/H ratio

D. Calorific value

55. With increase in the oxygen content of the coal, its ______________ decreases?
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A. Calorific value

B. Caking power

C. Both A. & B.

D. Neither A. nor B.

56. Quantity of coke oven gas produced by high temperature carbonisation of one ton of dry coal may be around ______________ Nm3?
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A. 3,000

B. 30,000

C. 30

D. 300
57. Combustion reaction of fuels is a/an ______________ reaction?
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A. Endothermic

B. None of these

C. Exothermic

D. Auto catalytic

58. To avoid fire by spontaneous combustion of coal due to its low temperature oxidation, it should be stored in___________________?
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A. Shallow and small piles

B. Fine sizes without the presence of any lump

C. Large heaps with small surface to volume ratio

D. Closed space without any ventilation facility

59. Calorific value of a typical dry anthracite coal may be around _____________ Kcal/kg?
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A. 15000

B. 8000

C. 4000

D. 1000

60. Proximate analysis of coal determines its ______________ content?
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A. None of these

B. Moisture, sulphur, nitrogen & fixed carbon

C. Moisture, volatile matter, ash & fixed carbon

D. Moisture, ash, sulphur & volatile matter

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

81. A sample of natural gas containing 80% methane (CH4) and rest nitrogen (N2) is burnt with 20% excess air. With 80% of the combustibles producing CO2 and the remainder going to CO, the Orsat analysis in volume percent is_________________?
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A. CO2 : 6.39, CO : 1.60, O2 : 3.99, H2O:25.96, N2:72.06

B. CO2 : 7.42, CO : 1.86, O2 : 4.64, N2:86.02

C. CO2 : 7.60, CO : 1.90, O2 : 4.75, N2 : 85.74

D. CO2 : 6.26, CO : 1.56, O2 : 3.91, H2O :15.66, N2 : 72.60

82. Weathering of coal during storage causes_______________?
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A. Increase in its friability

B. Decrease in its caking capacity

C. All A., B. and C.

D. Reduction in coal size

83. Which of the following fuels is the best for burning on chain grate stoker ?
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A. Pulverised coal

B. Non-caking coal

C. Coking coal

D. Caking coal

84. Largest constituent of blast furnace gas is__________________?
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A. CO2

B. CO

C. N2

D. H2

85. Wood charcoal is obtained by the destructive distillation of wood. It is used in the production of activated carbon, which is not used for the____________________?
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A. Solvent recovery from air and gases

B. Electrode manufacture

C. Decolourisation of sugar

D. Absorption of gases and vapor

86. For long flame and easy ignition, the coal used should have_________________?
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A. High volatile matter

B. Low ash

C. High calorific value

D. High ash

87. Main use of hard coke produced by high temperature carbonisation is in the ____________________ ?
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A. Iron blast furnace

B. Sinter making

C. Domestic ovens

D. Cupola in foundries

88. A fuel containing carbon and carbon monoxide (but containing no hydrogen or its compounds) is burnt in pure oxygen at constant pressure. Its gross calorific value as compared to net calorific value will be_________________?
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A. More

B. Less

C. Data insufficient; cant be predicted

D. Same
89. With increase in C/H ratio of a fuel, the amount of CO2 formed on its complete combustion____________________?
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A. Remain same

B. Either A. or B., depends on other factors

C. Decreases

D. Increases
90. The shift conversion reaction taking place during water gas manufacture is given by__________________?
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A. C + 2H2O ? CO2 + 2H2

B. None of these

C. C + H2O ? CO + H2

D. CO + H2O ? CO2 + H2
91. Which of the following has the highest flame velocity ?
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A. CO

B. CH4

C. C2H6

D. H2
92. Higher fuel combustion efficiency cannot be achieved by_________________?
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A. Preheating of fuel gases & combustion air

B. Adopting proper fuel firing technique & fuel preparation

C. Supplying correct amount of combustion air

D. Reducing sulphur content in the fuel
93. Supply of excess air for complete combustion of fuel is necessitated to facilitate___________________?
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A. None of these

B. Its thorough mixing with air

C. Attainment of high temperature

D. Attainment of chemical equilibrium

94. Desirable Micum Index values of metallurgical coke are ___________________?
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A. M40 > 78% and M10 < 10%

B. M40 > 4% and M10 10% and M10 98% and M10 < 2%

95. In Lurgi coal gasifier___________________?
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A. Coking coals cannot be used

B. Low carbon conversion efficiency is achieved

C. Entrainment of solids is higher

D. Larger quantity of coal can be processed
96. Lignite is ___________________?
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A. A coking coal

B. A high rank coal

C. Can be used for gasification and steam generation

D. A black banded coal which burns with a non-smoky yellowish flame

97. Power alcohol as compared to straight run gasoline has lower ________________?
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A. Viscosity

B. Specific gravity

C. Calorific value

D. Octane number

98. Traces of tar fog present in the coke oven gas is removed by_________________?
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A. Cyclone separator

B. Wet packed scrubber

C. Electrostatic precipitator

D. Washing with monoethanolamine

99. Bomb calorimeter can be used to determine the _____________ of the coal?
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A. Sulphur content

B. Calorific value

C. Both A. & B.

D. Neither A. nor B.

100. Which of the following fuel gases is heavier than air ?
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A. Blast furnace gas

B. Natural gas

C. Coke oven gas

D. Water gas