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1) Shaft furnaces are used for_______________________? a. Smelting b. Calcining c. Roasting d. All A., B. and C.
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2) Regenerators are installed in_______________? a. Coke ovens b. Open hearth furnace c. Both A. & B. d. Neither A. nor B.
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3) Presence of SO2 in furnace gases attacks the ferrous metal by way of_________________? a. Accelerating the rate of scaling b. Causing metal embrittlement c. Attacking the grain boundaries; particularly severe on low carbon and nickel bearing steels at high temperature d. All A., B. and C.
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4) In a heating process, a heat flow diagram in which the quantities of heat in the various items of a heat balance are represented by the width of a band is called the__________________? a. Ostwald chart b. Cox chart c. Sankey diagram d. None of these
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5) In producer gas making furnace, steam is added along with air to mainly control the____________________? a. Fusion of coal ash & clinker formation b. C. V. of producer gas c. Temperature of producer gas d. Tar content in producer gas
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6) Thermal efficiency of furnaces can be improved by____________________? a. Waste heat recovery from flue gas b. Minimising heat losses from furnace walls c. Maintaining proper draught d. All A., B. and C.
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7) Power required in case of forced draught as compared to induced draught (for the same draught produced) is___________________? a. Same b. Less c. More d. Either more or less; depends on the flue gas density
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8) While the fuel fired furnace can be used upto a maximum temperature of about 1700°C, the electric furnace can be used upto a temperature of about _____________ °C? a. 2000 b. 3000 c. 4500 d. 6000
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9) Rotary kilns are used in the____________________? a. Calcination of limestone & dolomite b. Cement manufacture c. Both A. and B. d. Neither A. nor B.
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10) Soaking pits are meant for heating steel_________________? a. Ingots b. Coils c. Sheets d. Slabs
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11) Pot furnace which is either regenerative or recuperative, is used in the manufacture of____________________? a. Glass b. Stainless steel c. Potteries d. Refractory bricks
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12) Very high pressure boilers are usually _____________ boilers? a. Fire tube b. Water tube c. Waste heat d. Natural circulation
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13) Thermal efficiency of blast furnace stoves used for heating blast (air) may be about _____________ percent? a. 20 b. 40 c. 60 d. 80
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14) Advantages of use of preheated combustion air are__________________? a. Saving in fuel consumption b. Reduction in scale losses c. Increase in flame temperature d. All A., B. and C.
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15) Maximum thermal efficiency of boiler may be about _____________ percent? a. 10 b. 25 c. 65 d. 90
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16) Thermal efficiency of a limestone calcination rotary kiln may be around ______________ percent? a. 20 b. 40 c. 65 d. 80
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17) Unit of furnace loading is____________________? a. Ton stock/hr/m2 hearth area b. Ton stock/hr c. Ton stock/m2 hearth area d. Both B. and C.
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18) Specific heating capacity of a furnace is expressed as_____________________? a. Weight heated/hr b. Weight heated/furnace volume c. Weight heated/hr/furnace volume d. None of these
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19) Coke ovens in steel plant are heated by____________________? a. Electricity b. Blast furnace gas/mixed gas c. Coke oven gas d. Both B. and C.
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20) Amount of coal lost in ash particle, which is carried through the boiler system, depends upon the__________________? a. Physical nature, ash content and fineness of the coal b. Amount of excess air supplied and load on the boiler c. Type of burner and combustion chamber d. All A., B. and C.
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