steam boilers engines nozzles and turbines Mcqs
151. Deaeration of feed water is carried out because it reduces ____________________?
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A. weight of water to be handled

B. corrosion caused by oxygen

C. pH value of water

D. cavitation of .boiler feed pumps

E. heat transfer coefficient

152. The three Ts for good combustion are____________________?
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A. thorough mixing, total air, and temperature

B. total air, time, and temperature

C. temperature, time, and turbulance

D. none of the above

E. total air, true fuel, and turbulance

153. In designing air preheater, the important design consideration is that_________________?
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A. stack gases should not be cooled to the dew point

B. handling and maintenance should be easier

C. heat transfer area should be optimum

D. approach temperature should be as low as possible

E. none of the above

154. Which is not correct statement about effect of sulphur in fuel ___________________?
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A. it erodes furnace walls

B. it helps in electrostatic precipitation of ash in flue-gases

C. it has heating value

D. it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low

E. none of the above

155. The number of drums in Benson steam generator is_________________?
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A. two

B. none of the above

C. no drum

D. one

E. one steam drum and one water drum

156. An economiser in a boiler______________________?
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A. increases life of boiler

B. decreases fuel consumption

C. increases steam pressure

D. decreases steam pressure

E. increases steam flow

157. Which is not correct statement about pulverised fuel firing ?
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A. separate mills are required to powder the coal

B. heat release can be easily controlled

C. it is the best technique for burning high ash content fuel having low fusion ash

D. fuel burns economically

E. high burning rate is possible

158. Evaporative capacity of boiler is expressed as____________________?
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A. steam pressure produced

B. kg of steam produced

C. kg of fuel fired

D. kg of steam produced per kg of fuel fifed

E. kg of water evaporated

159. The major axis of elliptical manholes on the shell should be provided___________________?
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A. vertically

B. circumferentially

C. on dished end

D. anywhere

E. longitudinally

160. Film boling occurs at _______________________?
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A. very low pressure

B. very high pressures

C. medium pressures

D. none of the above

E. atmospheric pressures

161. Secondary air is the used to_________________?
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A. convert CO (formed in lower zone of furnace) into C02 at higher zone

B. air delivered by induced draft fan

C. air fed to pulverisers

D. transport and dry the coal

E. provide air around burners for obtaining optimum combustion
164. For the same diameter and thickness of tube, a water tube boiler compared to a fire tube boiler has ____________________?
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A. heating surface depends on other parameters

B. equal heating surface

C. less heating surface

D. more heating surface

E. none of the above

165. Reheating of steam under ideal conditions takes place at constant __________________?
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A. enthaply

B. temperature

C. all of the above

D. entropy

E. pressure

166. In forced circulation type boiler__________________?
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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. feed pump is employed to supplement natural circulation in water wall type furnace

C. water is converted into steam in one pass without any recirculation

D. water is heated in a large number of tubes

E. 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

167. During storage, the heating value of coal __________________?
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A. increases

B. may increase or decrease depending upon the method of storage

C. none of the above

D. decreases

E. remains constant

168. Water at pressure of 4 kg/cm2 and 160C temperature when exposed to atmosphere will_________________?
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A. remain as it was

B. cool down

C. none of the above

D. flash i.e. get converted into steam

E. boil

169. The ultimate analysis of fuel lists _____________________?
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A. moisture and ash free heating value

B. fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

C. various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

D. various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

E. fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

170. At which pressure the properties of water and steam become identical_________________?
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A. 225.6 kg/cm2

B. 1 kg/cm2

C. 100 kg/cm2

D. 0.1 kg/cm2

E. it is never possible

171. Steam in water tube boiler as compared to fire tube boiler_________________?
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A. can be raised rapidly

B. is raised at same rate

C. none of the above is true

D. could be raised at fast/slow rate depending on design

E. is raisd at slower rate

172. The proximate analysis of fuel lists__________________?
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A. various chemical constituents, carbon, hydrogen, oxygen etc, plus ash as per-cents by volume

B. moisture and ash free heating value

C. fuel constituents as percents by weight of moisture, volatile, fixed carbon and ash

D. various chemical constituents, carbon, hydrogen, oxygen, etc, plus ash as per-cents by weight

E. fuel constituents as percents by volume of moisture, volatile, fixed carbon and ash

173. The maximum discharge through a chimney occurs when the height of chimney is_____________________?
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A. equal to the height of the hot gas column producing draught

B. outside temperature is very low

C. more than the tallest building nearby

D. around 200 meters

E. infinitely long

174. The fusible plug in small boilers is located ________________?
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A. over the combustion chamber

B. in the drum

C. above steam dome

D. at the inlet of chimney

E. in the fire tubes

175. The height of chimney in a power plant is governed by__________________?
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A. quantity of flue gases to be handled

B. limitation of construction facilities

C. all of the above

D. the draft to be created

E. control of pollution
176. Caking coals are those which __________________________?
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A. do not form ash

B. form lumps or masses of coke

C. burn completely

D. burn freely

E. show little or no fusing action

177. The safety valve at superheater as compared to drum safety valve setting is set at___________________?
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A. same value

B. lower value

C. any value

D. higher value

E. none of the above

178. Sulphur content of fuels is very important to the plant operators because it____________________?
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A. facilitates ash removal

B. promotes complete combustion

C. has high heating value

D. has highly corrosive effect

E. retards electric precipitation

179. Maximum energy loss in a boiler occurs due to _______________________?
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A. radiation losses

B. ash content

C. unburnt carbon in ash

D. flue gases

E. incomplete combustion

180. On Millier chart, the constant pressure lines_________________?
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A. diverge from right to left

B. none of the above

C. are equally spaced throughout

D. diverge from left to right

E. first rise up and then fall

182. The relative heat absorption for successively added equal areas of boiler convection heating surfaces____________________?
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A. first decreases and then increases

B. remains unaffected

C. first increases and then decreases

D. decreases

E. increases

183. A fusible plug is fitted in small boilers in order to ___________________?
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A. extinguish fire if water level in the boiler falls below alarming limit

B. control steam dome

C. avoid explosion

D. remove molten aslj

E. avoid excessive build up of pressure

184. Boiler stays are used to___________________?
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A. provide foundation of boiler

B. provide support for boiler

C. take care of failure in compression

D. take care of failure in shear

E. prevent flat surfaces under pressure from tearing apart
185. The difference between cornish boiler and lancashire boiler is that_________________?
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A. former is fire tube type and latter is water tube type boiler

B. former is water tube type and latter is fire tube type

C. former contains one fire tube and latter contains two fire tubes

D. none/of the above

186. If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by___________________?
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A. none of the above

B. bucket calorimeter

C. throttling calorimeter

D. separating calorimeter

E. combined separating and throttling calorimeter

187. Steam exhaust from high pressure turbine is reheated in _____________________?
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A. a separate coil located in convection path

B. economiser

C. boiler drum

D. superheater tubes

E. a separate coil

188. Pour point of fuel oil is the____________________?
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A. storage temperature

B. lowest temperature at which oil will flow under set condition

C. temperature at which fuel is pumped through burners

D. none of the above

E. temperature at which oil is transported

189. In ordetjo obtain superheated steam, a superheater is added in an existing boiler. As as result, furnace vacuum will _________________?
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A. may improve/worsen depending on size

B. improve C. worsen

C. unpredictable

D. remain unaffected

190. Proximate analysis of fuel is determination of percentage of ____________________?
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A. carbon, hydrogen, nitrogen, sulphur, moisture

B. higher calorific value

C. fixed carbon, ash, volatile matter, moisture

D. rough analysis

E. lower calorific value

191. Pick up the wrong statement about water tube boiler in comparison to fire tube boilers ______________________?
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A. former is used for high installed capacity

B. former generates steam at high pressure

C. former occupies less space for same power

D. rate of steam flow is more in former case

E. chances of explosion are less in former case
193. The safety valve on boiler drum compared to safety valve on super heater is set at ________________?
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A. same value

B. lower value

C. lower/higher depending on steam flow

D. higher value

E. unpredicatble