1) Coal tar fuels (CTF) as compared to petroleum based fuel oils have higher __________________? a. Calorific value b. Higher C/H ratio c. Sulphur content d. Difference in gross & net calorific value
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2) With increase in the oxygen content of the coal, its ______________ decreases? a. Calorific value b. Caking power c. Both A. & B. d. Neither A. nor B.
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3) The calorific value of ‘LPG’ (50% propane + 50% butane) is about ______________ kcal/Nm3? a. 5000 b. 25,000 c. 10,000 d. 15,000
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4) Fuel for a nuclear reactor (thermal) is ____________________? a. Uranium b. Plutonium c. Radium d. None of these
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5) Presence of free moisture in coal is most disadvantageous during_________________? a. Its pulverisation (as it requires more power) b. Combustion of fire slacks on the grates c. Handling (e.g. when emptying wagons) d. None of these
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6) The fuel ratio of a coal is__________________? a. The ratio of its percentage of fixed carbon to that of volatile matter b. Helpful in estimation of its rank c. Both A. and B. d. Neither A. nor B.
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7) Lurgi coal gasifier is a pressurised ______________ bed reactor? a. Moving b. Fixed c. Fluidised d. Entrained
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8) A travelling grate stoker is meant for the efficient burning of ______________ coal? a. Caking b. Pulverised c. Non-caking d. High ash
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9) Largest constituent of blast furnace gas is__________________? a. N2 b. CO c. CO2 d. H2
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10) The bright glow of a combustion process is the characteristic of ______________ temperature oxidation of coal? a. Fast & high b. Slow & low c. Slow & high d. Fast & slow
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11) C/H ratio is the maximum in case of_________________? a. Coal b. Furnace oil c. Natural gas d. Naphtha
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12) Traces of tar fog present in the coke oven gas is removed by_________________? a. Cyclone separator b. Wet packed scrubber c. Electrostatic precipitator d. Washing with monoethanolamine
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13) In general, the limit of inflammability/explosion limit of fuel gases is widened by the__________________? a. Increase in gas pressure b. Increase in temperature (i.e. preheating) c. Use of pure oxygen for combustion instead of air d. All A., B. & C.
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14) With increase in moisture content of coal, its___________________? a. Calorific value increases b. Caking properties diminish c. Swelling during carbonisation becomes excessive d. None of these
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15) Coke oven gas burns with a yellowish flame, because of the presence of __________________? a. CO2 b. CH4 c. H2 d. NH3
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16) Correct viscosity of furnace oil at the burner tip for proper atomisation is about 25 centistokes. To reduce the viscosity of high viscosity furnace oil (250 centistokes) to the correct atomisation viscosity (i.e. 25 cst), it should be preheated to about ______________°C? a. 70 b. 85 c. 105 d. 145
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17) Supply of excess air for complete combustion of fuel is necessitated to facilitate___________________? a. Its thorough mixing with air b. Attainment of chemical equilibrium c. Attainment of high temperature d. None of these
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18) ombustion of pulverised coal compared to the lumpy coal __________________? a. Provides better control of furnace temperature b. Facilitates combustion with lower excess air c. Provides higher thermal efficiency & flame temperature d. All A., B. & C.
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19) High rate of heating of coke ovens____________________? a. May damage its walls due to abrupt excessive swelling of coal b. Produces larger size coke c. Increases the time of carbonisation d. None of these
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20) Low temperature oxidation of stored coal results in the________________? a. Decrease in its caking power & calorific value b. Decrease in its carbon & hydrogen content c. Increase in its oxygen content d. All A., B. and A.
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21) High sulphur content in a fuel ______________ of the flue gases? a. Decreases the dew point b. Increases the dew point c. Reduces the combustion efficiency by limiting the permissible temperature reduction d. Both B. and C.
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22) Which of the following petrological constitutes is responsible for bright and lustrous black band of bituminous coal ? a. Vitrain b. Clarain c. Durain d. Fussain
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23) Which will have the least volatile matter and hence will be the most difficult to ignite ? a. Bituminous coal b. Coke c. Semi-bituminous coal d. Anthracite
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24) Number of macrocomponents present in coal according to Stopes are ___________________? a. Four b. Five c. Six d. Two
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25) Weathering of coal during storage causes_______________? a. Reduction in coal size b. Increase in its friability c. Decrease in its caking capacity d. All A., B. and C.
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26) The main function of primary air in pulverised coal fired burner is to_________________? a. Burn CO to CO2 b. Dry and transport the coal c. Have proper combustion by supplying it around the burner d. Preheat the tertiary air used for complete combustion of CO to CO2
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27) Which of the following has the highest calorific value (kcal/Nm3) ? a. Carburetted water gas b. Gobar gas c. Natural gas d. LPG
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28) Blast furnace gas compared to coke oven gas has_________________? a. Lower ignition temperature b. Narrower limit of inflammability c. Higher calorific value d. Lower theoretical flame temperature
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29) Which of the following is a poisonous fuel gas ? a. Coke oven gas b. Blast furnace gas c. Natural gas d. None of these
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30) Use of preheated air for combustion of fuel in the furnace, increases the___________________? a. Scale losses of the furnace stock b. Calorific value of the fuel c. Flame temperature d. None of these
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