Friday, May 3, 2019

MECHANICAL ENGINEERING MCQ ON BOILER PART - 6

203. When the enthalpy or total heat of steam is h kJ/kg and the sensible heat of the feed heater is hf1 kJ/kg, then the factor of evaporation is given by

(A) (h – hf1) / 2257 

(B) (h + hf1) / 2257

(C) (h × hf1) / 2257 

(D) (2h × hf1) / 2257

204. Deaerator is placed at higher elevation

(A) For good housekeeping

(B) For chemical treatment purpose

(C) To increase NPSHA and avoid Cavitation in Boiler feed pump

(D) To vent steam safely

205. Stoichiometric combustible mixture speaks about

(A) Fuel calorific value 

(B) Temperature of air and fuel

(C) Unburnt carbon in flue gas 

(D) Theoretical air

206. F and A (From and At) rating of the boiler is the amount of steam generated from

(A) Water at 0° C to steam at 100° C 

(B) Water at 27° C to steam at 100° C

(C) Water at 77° C to steam at 100° C 

(D) Water at 100° C to steam at 100° C

207. 3 Ts in boiler combustion represents

(A) Time - Transfer - Turbulence 

(B) Time - Temperature - Thermometer

(C) Time - Temperature - Turbulence 

(D) All of the Above

208. Alumina is a ............... type of refractory

(A) Acid 

(B) Basic

(C) Neutral 

(D) None of the above

209. In a CFBC boiler ............... are required to capture recycle large amount of bed material

(A) Settling camber 

(B) Mechanical cyclones

(C) Bag filters 

(D) Scrubbers

210. The best steam for indirect heating in most industrial process is

(A) As dry as possible 

(B) Superheated steam

(C) Wet steam 

(D) As wet as possible

211. The range of graduation on pressure gauge for a working pressure up to and including 35 kg/cm2 shall be

(A) Zero to 1.25 times the working pressure

(B) Zero to 1.50 times the working pressure

(C) Zero to 2.0 times the working pressure

(D) Zero to 2.5 times the working pressure

212. Which of the following parameter remain constant during ideal throttling process

(A) Pressure 

(B) Enthalpy

(C) Entropy 

(D) Temperature

213. Fish mouth opening is a term used to describe

(A) PA fan impeller cracks 

(B) Boiler tube failure

(C) Mill gear cracks 

(D) Turbine blade failure

214. Reheating of steam is used

(A) To increase efficiency 

(B) To increase work output

(C) To cool turbine blades 

(D) To reduce pollution

215. The type of firing used for a Pulverised coal-fired boiler is

(A) Over Firing 

(B) Tangential Firing

(C) Vertical Firing 

(D) None of the above

216. Water treatment for steam boiler is generally required

(A) To remove hydrogen 

(B) To prevent scale formation

(C) To improve combustion efficiency 

(D) To reduce stack temperature

217. Which of the following benefit is not achieved by maximising condensate recovery ?

(A) Maximization of boiler output 

(B) Reduction in water treatment cost

(C) Reduction in energy input cost 

(D) Minimization of flue gas exit temperature

218. In regenerative cycle feed water is heated by

(A) Flue Gas 

(B) Bleed steam from Turbine

(C) Auxiliary Heaters 

(D) All of the above

219. The ideal range of pH value for boiler feed water is

(A) 3.5 - 5 

(B) 5.5 - 6

(C) 7 - 7.5 

(D) 8.5 - 9.5

220. A device which is used to drain off water from steam pipes without the escape of steam is called

(A) Steam separator 

(B) Steam trap

(C) Pressure reducing valve 

(D) Injector



221. Boiler parameters are expressed by

(A) Tonnes/hr of steam 

(B) The pressure of steam in kg/cm2

(C) The temperature of steam in °C 

(D) All of the mentioned

222. Hydrated lime is used primarily to reduce which type of hardness in boiler feed water?

(A) Hardness due to calcium sulphate 

(B) Bicarbonate hardness

(C) Hardness due to calcium chloride 

(D) All of the mentioned

223. Which type of heat loss cannot be controlled by boiler design

(A) Loss of heat due to the combustion of hydrogen

(B) Loss of heat due to dry flue gas

(C) Loss of heat due to radiation

(D) All of the above

224. Which of the following boiler accessories does not need flue gas for its operation

(A) Economizer 

(B) Preheater

(C) Injector 

(D) Superheater

225. In oil-fired systems, poor oil fires can result from

(A) Improper viscosity 

(B) Carbonization of tips

(C) Deterioration of diffusers or more spin plates 

(D) All of the mentioned


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