71. The function of injector used in small capacity boilers is to____________________?
A. create vacuum
B. inject chemical solution in feed pump
C. pump water, similar to boiler feed pump
D. add make up water in the system
E. none of the above

72. In designing air preheater, the important design consideration is that_________________?
A. approach temperature should be as low as possible
B. handling and maintenance should be easier
C. heat transfer area should be optimum
D. stack gases should not be cooled to the dew point
E. none of the above

73. The temperature of flue gases at air heater outlet should be__________________?
A. 100°C
B. above dew-point temperature of flue gases
C. below dew-point temperature of flue gases
D. less than wet bulb temperature of flue gases
E. above wet bulb temperature of flue gases

74. In a recuperative air preheater, the heat is transferred____________________?
A. from a metal wall from one medium to another
B. from heating an intermediate material and then heating the air from this material
C. by direct mixing ,
D. heat is transferred by bleeding some gases from furnace
E. none of the above

75. With increase in load, convection super heater has_______________________?
A. drooping characteristic
B. linear characteristic
C. rising characteristic
D. flat characteristic
C. none of the above

76. In which of the following boilers, the draught in furnace is increased by utilizing exhaust steam from engine__________________?
A. Lancashire boiler
B. locomotive boiler
C. Babcock and Wilcox boiler
D. Cochran boiler
E. Benson boiler

77. Green coal, in order to be burnt, must be____________________?
A. heated sufficiently
B. burnt in excess air
C. heated to its ignition point
D. burnt as powder
E. burnt as lumps

78. Sulphur in coal results in___________________?
A. causing clinkering and slagging
B. corroding air heaters
C. spontaneous combustion during coal storage
D. facilitating ash precipitation
E. all of the above

79. The behavior of coal in a furnace is determined by_______________________?
A. the content of Sulphur
B. the content of ash and heating value
C. the proximate analysis
D. the exact analysis
E. its type

80. Pour point of fuel oil is the____________________?
A. lowest temperature at which oil will flow under set condition
B. storage temperature
C. temperature at which fuel is pumped through burners
D. temperature at which oil is transported
E. none of the above

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