Steam Boilers, Engines, Nozzles & Turbines Mcqs - Set 10

1)   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
Answer  Explanation 

ANSWER: above dew-point temperature of flue gases

Explanation:
No explanation is available for this question!


2)   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
Answer  Explanation 

ANSWER: from a metal wall from one medium to another

Explanation:
No explanation is available for this question!


3)   With increase in load, convection superheater has_______________________?

a. drooping characteristic
b. linear characterisstic
c. rising characteristic
d. flat characteristic
e. none of the above
Answer  Explanation 

ANSWER: rising characteristic

Explanation:
No explanation is available for this question!


4)   In which of the following boilers, the draught in furnace is increased by utilising exhaust steam from engine__________________?

a. lancashire boiler
b. locomotive boiler
c. babcock and wilcox boiler
d. cochran boiler
e. benson boiler
Answer  Explanation 

ANSWER: locomotive boiler

Explanation:
No explanation is available for this question!


5)   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. radiation
e. all of the above
Answer  Explanation 

ANSWER: all of the above

Explanation:
No explanation is available for this question!


6)   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 mixtur
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
e. water is heated in a large number of tubes
Answer  Explanation 

ANSWER: water is converted into steam in one pass without any recirculation

Explanation:
No explanation is available for this question!


7)   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
Answer  Explanation 

ANSWER: boiler efficiency, turhine efficiecny, generator efficiency

Explanation:
No explanation is available for this question!


8)   The radius of a dished head is taken approximately as______________________?

a. one-fourth
b. half
c. one
d. two
e. three
Answer  Explanation 

ANSWER: one

Explanation:
No explanation is available for this question!


9)   Thermal efficiency of a thermal power plant is of the order of___________________?

a. 15%
b. 20%
c. 30%
d. 45%
e. 60%
Answer  Explanation 

ANSWER: 30%

Explanation:
No explanation is available for this question!


10)   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
e. ecomomical
Answer  Explanation 

ANSWER: high ignition point

Explanation:
No explanation is available for this question!


11)   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
e. separate mills are required to powder the coal
Answer  Explanation 

ANSWER: it is the best technique for burning high ash content fuel having low fusion ash

Explanation:
No explanation is available for this question!


12)   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
e. to minimise radiation losses
Answer  Explanation 

ANSWER: separate ash from coal

Explanation:
No explanation is available for this question!


13)   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
e. moisture in coal is removed before firing by heating it with hot air
Answer  Explanation 

ANSWER: it increases thermal efficiency

Explanation:
No explanation is available for this question!


14)   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
e. none of the above
Answer  Explanation 

ANSWER: it erodes furnace walls

Explanation:
No explanation is available for this question!