The maximum discharge through a chimney occurs when the height of chimney is_____________________?
(A) infinitely long
(B) around 200 meters
(C) equal to the height of the hot gas column producing draught
(D) outside temperature is very low
(D) more than the tallest building nearby
Which is not correct statement about effect of sulphur in fuel ___________________?
(A) it has heating value
(B) it helps in electrostatic precipitation of ash in flue-gases
(C) it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
(D) it erodes furnace walls
(D) none of the above
Which is not the correct statement about moisture in coal ______________________?
(A) inherent moisture and surface mois¬ture are different things
(B) in some coals moisture may be present upto 40%
(C) some moisture in coal helps in better burning which is not possible with completely dry coal
(D) it increases thermal efficiency
(D) moisture in coal is removed before firing by heating it with hot air
Which is not correct statement about the function of furnace____________________?
(A) to provide proper conditions for con-tinuous complete combustion
(B) mix fuel with air and ignite
(C) separate ash from coal
(D) maintain heat supply to prepare and ignite the incoming fuel
(D) to minimise radiation losses
Which is not correct statement about pulverised fuel firing ?
(A) high burning rate is possible
(B) heat release can be easily controlled
(C) fuel burns economically
(D) it is the best technique for burning high ash content fuel having low fusion ash
(D) separate mills are required to powder the coal
Pick up wrong statement about desired properties of a good fuel__________________?
(A) high calorific value
(B) produce minimum smoke and gases
(C) ease in storing
(D) high ignition point
(D) ecomomical
Thermal efficiency of a thermal power plant is of the order of___________________?
(A) 15%
(B) 20%
(C) 30%
(D) 45%
(D) 60%.
The radius of a dished head is taken approximately as______________________?
(A) one-fourth
(B) half
(C) one
(D) two
(D) 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
(D) 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 in the form of mixture of water and steam
(C) feed pump is employed to supplement natural circulation in water wall type furnace
(D) water is converted into steam in one pass without any recirculation
(D) water is heated in a large number of tubes