Steam Boilers Engines Nozzles and Turbines

181. Water tube boilers are those in which

1. flue gases pass through tubes and water around it
2. water passes through the tubes and flue gases around it
3. work is done during adiabatic expansion
4. change in enthalpy
5. none of the above.

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182. Which device is used in thermal power plants to reduce level of pollution

1. induced draft fan
2. smoke meter
3. chimney
4. precipitator
5. pulveriser.

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183. Which is not correct statement about effect of sulphur in fuel

1. it has heating value
2. it helps in electrostatic precipitation of ash in flue-gases
3. it leads to corrosion of air heaters, ducting, etc. if flue gas exit temperature is low
4. it erodes furnace walls
5. none of the above.

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184. Which is not correct statement about pulverised fuel firing

1. high burning rate is possible
2. heat release can be easily controlled
3. fuel burns economically
4. it is the best technique for burning high ash content fuel having low fusion ash
5. separate mills are required to powder the coal.

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185. Which is not correct statement about the function of furnace

1. to provide proper conditions for con-tinuous complete combustion
2. mix fuel with air and ignite
3. separate ash from coal
4. maintain heat supply to prepare and ignite the incoming fuel
5. to minimise radiation losses.

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186. Which is not the correct statement about moisture in coal

1. inherent moisture and surface moisture are different things
2. in some coals moisture may be present upto 40%
3. some moisture in coal helps in better burning which is not possible with completely dry coal
4. it increases thermal efficiency
5. moisture in coal is removed before firing by heating it with hot air.

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187. Which of the following coals has the highest calorific value

1. anthracite coal
2. bituminous coal
3. lignite
4. peat
5. wood.

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188. Which of the following gases has the highest calorific value

1. producer gas
2. coal gas.
3. water gas
4. blast furnace gas
5. coke oven gas.

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189. Which of the following is a fire tube boiler

1. locomotive boiler
2. Babcock and Wilcox boiler
3. Stirling boiler.
4. all of the above
5. none of the above.

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190. Which of the following is a water tube boiler

1. locomotive boiler
2. Cochran boiler
3. Cornish boiler
4. Babcock and Wilcox boiler
5. Lancashire boiler.

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