chemical engineering furnace technology MCQs – Page 4

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 Review each marked answer and report any item that may be outdated or unclear.

chemical engineering furnace technology Mcqs
61. In practical operation of any furnace, zero oxygen percentage or theoretical CO2 percentage in flue gas is rarely achieved, because of__________________?
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A. Use of pulverised solid fuels

B. Imperfect mixing of fuel & air and infiltration of air

C. Use of excessive positive draft in the furnace

D. Use of non-preheated combustion air

62. Furnace pressure is normally controlled by regulating the__________________?
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A. Fuel gas pressure

B. Air pressure

C. Speed of I.D. fan

D. Damper
63. Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by______________________?
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A. Oxygen enrichment of combustion air

B. Preheating the combustion air

C. All A., B. & C.

D. Preheating the fuel gas

64. Flue gas outlet temperature from the chimney of any furnace should be ideally about ______________ C?
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A. 50

B. 100

C. 150

D. 250

65. In a furnace, the heat taken by the charge/stock and the heat lost to the furnace structure & flue gases depends on the__________________?
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A. Thermal conductivity of the charge & structural materials of furnace

B. Rate of firing and emissivity of flame

C. Nature of process; whether batch, continuous or intermittent

D. All A., B. and C.
66. In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of_________________?
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A. Combustion of coal by supplying it around the burner

B. Transportation of coal

C. Preheating the primary air

D. Drying of coal

67. Which is the most thermally efficient furnace _______________________?
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A. Boiler furnace

B. Rotary kilns

C. Reheating furnace

D. Reverberatory furnace

68. Circulation of gases in furnace is caused by the_________________?
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A. Change in volume during a change of temperature

B. All A., B. and C.

C. Furnace pressure in conjunction with draft in flues

D. Difference in density between hot and cold gases

69. Ceramic coating material for furnace refractory, which increases its emissivity and thus the radiation heat transfer rate in the furnace, comprises of_________________?
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A. Zircon powder

B. Thoria

C. Graphite powder

D. Beryllium

70. The rate of scaling of furnace stock depends upon the_________________?
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A. Temperature

B. All A., B. and C.

C. Time

D. Nature of atmosphere

71. Regenerators are normally provided in the____________________?
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A. Glass melting furnace

B. All A., B. and C.

C. By product coke ovens

D. Open hearth furnace

72. Very high pressure boilers are usually _____________ boilers?
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A. Fire tube

B. Water tube

C. Waste heat

D. Natural circulation
73. A refractory wall separating the stock and the source of heat is provided in a__________________?
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A. None of these

B. Updraft kiln

C. Continuous furnace

D. Muffle furnace
74. Power required in case of forced draught as compared to induced draught (for the same draught produced) is___________________?
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A. Either more or less; depends on the flue gas density

B. Same

C. More

D. Less
75. Heat transfer takes place through a liquid medium surrounding the submerged material under heating, in case of a/an__________________?
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A. Annealing furnace

B. Steam boiler

C. Salt bath furnace

D. Blast furnace

76. Which of the following is a batch furnace ?
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A. None of these

B. Glass tank furnace

C. Cupola

D. Reheating furnace

77. Overall thermal efficiency of a lumpy coal fired suitably designed heating furnace, if operated & maintained properly may be about ____________ percent?
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A. 45-50

B. 65-70

C. 15-Oct

D. 25-30
78. Which of the following is not a recuperative furnace ?
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A. Coke oven

B. Soaking pit

C. Reheating furnace

D. Steam boiler

79. Advantages of use of preheated combustion air are__________________?
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A. All A., B. and C.

B. Increase in flame temperature

C. Reduction in scale losses

D. Saving in fuel consumption

80. Which of the following is the most suitable for preheating combustion air above 650C ?
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A. None of these

B. Regenerator

C. Ceramic recuperator

D. Metallic recuperator