In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is

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Question
In a boiler, feed water supplied per hour is 205 kg while coal fired per hour is 23 kg. The net enthalpy rise per kg of water is 145 kJ. If the calorific valve of the coal is 2050 kJ/kg, then the boiler efficiency will be
Options
A. 56%
B. 63%
C. 74%
D. 78%

Correct Answer

63%

More questions

1. Which of the following statement is correct?
Options
A. In a compressible flow, the volume of the flowing liquid changes during the flow.
B. A flow in which the volume of the flowing liquid does not change, is called incompressible flow.
C. When the particles rotate about their own axes while flowing, the flow is said to be rotational flow.
D. all of the above

2. Which one of the following event would reduce volumetric efficiency of a vertical compression ignition engine?
Options
A. inlet valve closing after bottom dead centre
B. inlet valve closing before bottom dead centre
C. inlet valve opening before top dead centre
D. exhaust valve closing after top dead centre

3. Which of the following statement is correct?
Options
A. Compression ratio for petrol engines varies from 6 to 10.
B. Higher compression ratio in diesel engines results in higher pressures.
C. Petrol engines work on Otto cycle.
D. all of the above

7. Which one of the following is the effect of blade shape on performance of a centrifugal compressor?
Options
A. Backward curved blades has poor efficiency
B. Backward curved blades lead to stable performance
C. Forward curved blades has higher efficiency
D. Forward curved blades produce lower pressure ratio

8. Which of the following statement is wrong?
Options
A. The reaction turbines are used for low head and high discharge.
B. The angle of taper on draft tube is less than 8�.
C. An impulse turbine is generally fitted slightly above the tail race.
D. A Francis turbine is an impulse turbine.

9. A turbine is required to develop 1500 kW at 300 r.p.m. under a head of 150 m. Which of the following turbine should be used?
Options
A. Pelton wheel with one nozzle
B. Pelton wheel with two or more nozzles
C. Kaplan turbine
D. Francis turbine

10. Which of the following statement is correct?
Options
A. The centrifugal pump is suitable for large discharge and smaller heads.
B. The centrifugal pump requires less floor area and simple foundation as compared to reciprocating pump.
C. The efficiency of centrifugal pump is less as compared to reciprocating pump.
D. all of the above

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