1) Example of an indirectly heated furnace is__________________? a. Hood annealing furnace b. Muffle furnace c. Both A. and B. d. Neither A. nor B.
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2) In case of pulverised coal fired steam boiler, the secondary air serves the main purpose of_________________? a. Transportation of coal b. Drying of coal c. Combustion of coal by supplying it around the burner d. Preheating the primary air
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3) Which of the following is a directly fired intermittent furnace ? a. Walking beam reheating furnace b. Reverberatory furnace c. Tower furnace d. Tunnel kiln
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4) Temperature of a furnace fired with low calorific value fuel gas (i.e. lean gas) can be increased by______________________? a. Preheating the combustion air b. Oxygen enrichment of combustion air c. Preheating the fuel gas d. All A., B. & C.
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5) If fuel and air are mixed ahead of the burner, it is called a/an ______________ burner? a. Premix b. Outside mixing type c. Rotary d. Diffusion
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6) Heat balance of furnace provides means of determining the_________________? a. Thermal efficiency of the process b. Sources of heat losses c. Scope of reduction of heat losses d. All A., B. and C.
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7) Means for giving direction to the circulation of gases in furnaces are_____________________? a. Fans b. Arrangement of heating stock in the furnaces c. Location of outlet ports and heating & combustion devices d. All A., B. and C.
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8) Oxygen percentage in the flue gas coming out of a gaseous fuel fired furnace should be ideally about _____________ percent? a. < 2 b. < 5 c. < 8 d. < 10
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9) Which of the following accentuates clinkering troubles on furnace grate burning coal ? a. Low reactivity of carbonised residue containing high proportion of iron & sulphur b. Low forced draft & fuel bed temperature c. Thick firebed and preheated primary air d. All A., B. and C.
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10) Cement Kiln is a___________________? a. Rotary Kiln b. Tunnel Kiln c. Natural draft furnace d. Batch furnace
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11) Which furnace employs an I.D. fan for the removal of flue gases from the furnace ? a. Coke oven b. Blast furnace stoves c. Beehive coke oven d. High pressure boiler
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12) Reverberatory furnace is used for_____________________? a. Roasting/reduction of ores b. Annealing steel coil c. Heating air d. Steel melting
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13) Fuel used in B.F. stove is______________________? a. Pulverised coal b. Furnace oil c. Blast furnace gas/mixed gas d. Coke oven gas
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14) In a furnace operation, which is not preheated ? a. Solid fuels b. Hydrocarbon containing fuel gases (e.g. coke oven gas, refinery gas etc.) c. Both A. and B. d. Neither A. nor B.
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15) The main function of a muffle in the muffle furnace is to__________________? a. Protect the charge from the effects of the products of combustion b. Smooth out temperature inequalities on the combustion side of the muffle wall c. Both A. & B. d. Neither A. nor B.
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16) Heat transfer rate to the stock/charge in the furnace does not depend upon the________________? a. Emissivity of the refractory walls b. Size of the furnace c. Use of waste heat recovery equipments d. Thickness of the stock
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17) In order to maintain an oxidising atmosphere in a furnace, it should have__________________? a. More of excess air b. Less of excess air c. More of CO in flue gas d. More of CO2 in flue gas
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18) Which is a regenerative furnace ? a. Coke oven heating chamber b. Open hearth furnace c. Both A. and B. d. Neither A. nor B.
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19) In a furnace employing forced draught as compared to induced draught______________________? a. Air is sucked in, so air leaks are more and hence the furnace efficiency is reduced b. The fan operates hot and hence blades are liable to corrosion and erosion c. Positive pressure exists in the furnace d. None of these
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20) An example of recuperative furnace is the__________________? a. Soaking pit b. Open hearth furnace c. Coke ovens d. None of these
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