Steam Boilers

Thermal efficiency of a thermal power plant is of the order of___________________? A. 15% B. 20%C. 30% D. 45% E. 60%.

The radius of a dished head is taken approximately as______________________? A. one-fourth B. halfC. one D. two E. three

The overall efficiency of thermal power plant is________________? A. boiler efficiency, turhine efficiecny, generator efficiency B. all the three above plus gas cycle efficiency C. carnot cycle efficiency D. regenerative cycle efficiency E. rankine cycle efficiency

In forced circulation type boiler__________________? A. heating takes place at bottom and the water supplied at bottom gets converted into the mixture of steam bubbles and hot water which rise to drum B. water is supplied in drum and through down-comers located in atmospheric condition it passes to the water wall and rises to drum…

The heat loss in a boiler takes place in the form of________________? A. heat carried away by flue gases B. heat carried away by ash C. moisture present in fuel and steam formed by combustion of hydrogen in fuel D. radiationE. all of the above

In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine__________________? A. lancashire boilerB. locomotive boiler C. babcock and wilcox boiler D. cochran boiler E. benson boiler

With increase in load, convection superheater has_______________________? A. droog characteristic B. linear characterissticC. rising characteristic D. flat characteristic C. none of the above

In a recuperative air preheater, the heat is transferred____________________? A. from a metal wall from one medium to another B. from heating an itermediate 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

The temperature of flue gases at air heater outlet should be__________________? A. 100°CB. 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

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 optimumD. stack gases should not be cooled to the dew point E. none of the above