Jharkhand BOE (2015) Examination Paper-2 Discussion

 Choose the correct answer

Q 1. The material commonly used in boiler drum is.

        Ans- SA 213 T11

Q 2. Frequency of soot blowing in a boiler is decided by 

      Ans- Temperature of outgoing flue gas

Q 3. To improve wear resistant which element is used in boiler metallurgy 

    Ans- Mo (Molybdenum)

Q 4. Caustic embrittlement is caused by

   Ans- High PH

Q 5. The chemical is used in boiler drum for chemical treatment of boiler water

  Ans- Na3PO4 (Trisodium Phosphate)

Q 6. Indicate a permissive which is not among the necessary permissive for light up any boiler

A. All vents closed   B. Minimum drum level  C. Boiler purge complete  D. Atomising Air/Steam is available.

Q 7. For every 38 degc of superheat above saturation temperature the heat gain in station heat rate is approximately

   Ans- Approx 5 %

Q 8. What is the location of radiant super heater in furnace.

  Ans- In second pass

 Q 9. The overall efficiency of supercritical boiler is

  Ans- 42%

Q 10. From the energy efficiency point of view which flow regulating device is the most suitable for radial flow fan.

Ans- Variable frequency drive.

Q 11. The fusible plug location in small boiler is

Ans- Over the combustion chamber.

Q. 12. Reheat cycle is used in thermal power plant for what ?

Ans- To increase the plant efficiency and Prevent excess of 10-12 % moisture content in last stages of turbine.

Q 13. When steam is first being allowed into piping system, What care should take before steam allowed into piping.

Ans- All drain valve should be open condition and All condensate should be drained.

Q 14. What is the effect Caustic nature of water in boiler ?

Ans- Dissolving iron and magnetite to form sodium ferrate.

Q 15. Insufficient air in boiler will result in.

  Ans-  i) Carbon in flue gas. ii) High CO in flue gas iii) Low oxygen reading in flue gas.

Q 16. Generally packaged boilers are

Ans- Horizontal return tubular.

Q 17. Reheating of steam in ideal condition takes place at constant.

Ans- Pressure.

Q 18. Size of boiler tubes is specific by

Ans- Outside diameter and thickness.

Q 19. Which super heater in boiler has dropping characteristics

Ans- Radiant roof super heater.

Q 20. Short term overheating usually exhibits

Ans- Thin lip longitudinal rupture.

Fill in the blanks choosing appropriate answer

Q 1. The RPM of LUNGSTROM air pre heater is

     Ans- 2 to 3 RPM

Q 2. The material used in cold end heating elements of rotary air pre heater is

   Ans- Corten steel

Q 3. The safety device used in rotary air heater is 

   Ans- Rotor stoppage sensor

Q 4. The ceramics used to manufacture tiles of coal duct pipe lines contains approx 90 % of

   Ans- Alumina

Q 5. The speed range of bowl mill is 

  Ans- 50-100 rpm

Q 6. Positive displacement pump fuel oil pumps should not run for prolonged periods with the relieve valves open because this causes

  Ans- Loss of power

Q 7. A Bourdon tube is a device used to measure

  Ans- Pressure

Q 8. The maximum temperature limit of of SA 213 TP347H for boiler operations is 

  Ans- 705 deg c

Q 9. An impurity in water requires critical attention in high pressure boiler is 

 Ans- Silica

Q 10. In DM plant the degasser is used to remove 

Ans- CO2

Indicate True or False

Q 1. The purpose of oil burner register is to stabilize the oil flame adjacent to sprayer tip (T)

Q 2. Economizer recirculation system is provided for increasing the output of boiler (F)

Q 3. Incomplete combustion can be best judged by measuring CO in flue gas (T)

Q 4. Ball and tube mill crushes the coal on the principle of impact (T) 

Q 5. Reheating of steam in turbine increase the work done through turbine and its efficiency  (T)

Q 6. Wet steam shall be more effective for cleaning boiler wall surfaces using wall/soot blowers in furnaces (F)

Q 7. Stress Assisted corrosion is related to weld joint failure (T)

Q 8. Hydra-step is a device mostly used to monitor Deaerator level (F)

Q 9. Classifier installed in a mill is primarily used for varying mill output (T)

Q 10. LRSB or Wall blower are operated to increase the heat transfer in the boiler (T)

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