Friday, May 3, 2019

MECHANICAL ENGINEERING MCQ ON BOILER PART - 2

122. Stochiometric air required for combustion of Bagasse is about

(A) 13.7 


(B) 3.2


(C) 6 


(D) 18



123. Calculate the boiler efficiency (in percentage) of the certain boiler if Evaporation ratio is 5. Enthalpy difference between saturated steam and feed water is 1500 kcal/kg. Given, the Gross Calorific Value of fuel is 10,000 kcal/kg of fuel

(A) 30 


(B) 50


(C) 75 


(D) 65


124. The enthalpy of steam at 170 degree Celsius with wetness fraction of 0.25 would:


(A) Have enthalpy greater than steam at 170 degree Celsius with dryness fraction of 0.50


(B) Have enthalpy lower than the enthalpy of saturated water at 170 degree Celsius


(C) Have enthalpy lower than steam at 170 degree Celsius with wetness fraction of 0.35


(D) None of the above


125. Which of the following would have the maximum resistance of heat transfer to a steam pipe when

indirect heating is carried out (the product and steam does not intermix)

(A) Air film


(B) Condensate film


(C) Scales 


(D) Metal thickness


126. The power output is least for which of the following cogeneration system :


(A) Reciprocating engine based


(B) Gas Turbine based


(C) Extraction-condensing steam turbine based


(D) Back-pressure steam turbine based


127. Pre-heating of combustion air in an oil-fired furnace by 20° C will save about ............... % of fuel


(A) 0.3 


(B) 1


(C) 1.5 


(D) 0.6


128. The blowdown for safety valve is given by


(A) (Set pressure)/ Set pressure - Reseating pressure


(B) Reseating pressure/ Set pressure


(C) (Set pressure - Reseating pressure)/ (Set pressure)


(D) Reseating pressure/ (Reseating pressure - Set pressure)


129. The principle of Mechanical Deaeration is based on which of the following scientific laws?


(A) Dalton’s law of partial pressures 


(B) Henry’s Law


(C) Charles Law 


(D) Both (A) and (B)


130. Which of the following is the most suitable candidate to act as an Emergency Shutdown valve?


(A) Gate Valve 


(B) Globe Valve


(C) Butterfly Valve 


(D) Both (A) and (C)


131. In which of the following units can a boiler’s rating be described?


(A) kg of steam generated at specified pressure and temperature


(B) MW of turbine capacity


(C) Kcal/hour (Rate of heat generation in the furnace)


(D) All of the above


132. Which of the following will be ideal for heat transfer in a heat exchanger


(A) Superheated steam 


(B) Saturated dry steam


(C) Wet steam 


(D) Hot water


133. Statement 1: The use of Low sulphur coals allows for the reduction in the flue gas exit temperature.


Statement 2: The use of low sulphur coals increases the collection efficiency of electrostatic

precipitator.

(A) If both statements are correct


(B) If statement 1 is correct and statement 2 is false


(C) If statement 1 is incorrect and statement 2 is correct


(D) If both, statement 1 and statement 2 are incorrect



134. Statement 1: A mechanical dust collector (cyclone separator) is installed after the Electrostatic

precipitator

Statement 2: It is preferable to install a mechanical dust collector (cyclone separator) upstream of

an Air Preheater.

(A) If both statements are correct


(B) If statement 1 is correct and statement 2 is false


(C) If statement 1 is incorrect and statement 2 is correct


(D) If both, statement 1 and statement 2 are incorrect


135. Boiler drum and other cylindrical component having an internal diameter greater than 600 mm shall

be hydraulically tested at

(A) 1.5 times the maximum permissible working pressure


(B) 1.25 times the maximum permissible working pressure


(C) 1.25 times the maximum design pressure


(D) None of the above


136. Water temperature at hydraulic testing shall be in the range of


(A) 20 - 50° C 


(B) 18 - 28° C


(C) 25 - 55° C 


(D) 40 - 55° C


137. For boiler fittings of the cast iron material can be used in case of


(A) The temperature of 250° C 


(B) The pressure of 17.5 bar gauge


(C) Boiler blowdown fittings 


(D) The pressure of 150 PSI


138. Safety valve having seat diameter not less than 32 mm should reset at


(A) At least 5% below but not more than 10% below safety valve set pressure


(B) At least 2.5% below but not more than 5% below safety valve set pressure


(C) At least 2.5% below but not more than 10% below safety valve set pressure


(D) At least 1.5% below but not more than 5% below safety valve set pressure


139. For boiler pressure of 20 kg/cm2, pressure gauge ideal range should be


(A) 0 - 80 kg/cm2 


(B) 0 - 40 kg/cm2


(C) 0 - 60 kg/cm2 


(D) 0 - 20 kg/cm2


140. Boiler registry number shall be engraved on boiler


(A) Within a period of one month from boiler registration


(B) Within a period of six months from boiler registration


(C) Within a period of one month from the date of receipt of it


(D) Within a period of six months from the date of receipt of it


141. Boiler manufacturer shall maintain record pertaining to all boiler certificates and approved drawings

for the period of

(A) One year 


(B) Two year


(C) Five year 


(D) Ten year

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Idioms mcq For Competitive Exams

Idioms mcq For Competitive Exams