Steam Boilers

51. Heating of dry steam above saturation temperature is known as

1. enthalpy
2. superheating
3. supersaturation
4. latent heat
5. super tempering.

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52. Heating value of fuel used is as on fired basis. If it is reported for dry or moisture free fuel, then latter should be multiplied by the following factor to correct for as fired value

1. (1- moisture content)
2. (1 + moisture content)
3. 1 + moisture content
4. 1 – moisture content
5. none of the above.

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53. Heating wet steam at constant temperature is heating it at constant

1. volume
2. pressure
3. entropy
4. enthalpy
5. none of the above.

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54. Hygrometery deals with the

1. Hygroscopic substances
2. water vapour in air
3. temperature of air
4. pressure of air
5. density measurement.

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55. If a steam sample is nearly in dry condition, then its dryness fraction can be most accurately determined by

1. throttling calorimeter
2. separating calorimeter
3. combined separating and throttling calorimeter
4. bucket calorimeter
5. none of the above.

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56. If partial pressure of air and steam be pa andps respectively in a condenser, then according to Dalton’s law, the pressure in condenser is equal to

1. Ps-Pa
2. pa-ps
3. Pa+P,
4. all of the above.
5. none of the above.

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57. If xx and x2 be the dryess fractions obtained in separating calorimeter and throttling calorimeter respectively, then the actual dryness fraction of steam will be

1. xxx2
2. x, + x2
3. all of the above.
4. none of the above.

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58. In a recuperative air preheater, the heat is transferred

1. from a metal wall from one medium to another
2. from heating an itermediate material and then heating the air from this material
3. by direct mixing ,
4. heat is transferred by bleeding some gases from furnace
5. none of the above.

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59. In a throttling process

1. steam temperature remaisn constant
2. steam pressure remains constant
3. steam enthalpy remains constant
4. steam entropy remains constant
5. steam volume remains constant.

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60. In accelerated circulation type boiler

1. heating takes place at bottom and the water supplied at bottom gets converted into the mixture of stdam bubbles and hot water which rise to durm
2. water is supplied in drum and through downcomers” located in atmospheric conditon it passes to the water wall and rises to durm in the from of mixture of water and steam
3. feed pump is employed to supplement natural circulation in water wall type furnace
4. water is converted into steam in one pass without any recirculation
5. water is fed under high pressure and high velocity.

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