Best 25 question and answer for boiler first and second class operator viva examination 2017
Best 25 question and answer for boiler first and second class operator viva examination 2017 :-
Q.1 what is boiler?
Ans. According the boiler rule act 1923 “ boiler is a closed vessel exceeding 22.75 liters in capacity which is used expressly for generation of steam under pressure and including any mounting or other fitting attached to such vessel , which is wholly and partilly under pressure when steam is shut off .
Boiler is closed vessel in which the heat is produced by combustion of fuel is transferred to feed water to generate steam. Boiler is heat exchanger.
Q.2 boiler mounting and fitting?
Ans. Mounting of the boiler is which is responsible for the safe operation of the boiler i.e safety valve , water level gauge , pressure gauge , blow down valve etc,
Fitting of the boiler is a interregnal part of the boiler and helps to run the boiler in efferent manner i.e super heater , economizer , air heater , soot blower , feed pum etc.
Q.3 why we open start up vent before start of boiler ?
Ans. Start up vent is using during startup of the boiler because of when we light up the boiler during cold start then the steam generation started and the furnace temperature increasing rapidly also the temperature in the super heater zone also increases during start up MSSV of the boiler is closed condition so the steam not escaping through the boiler hence no circulation of steam in super heater zone take place so it’s a highly chance of super heater over temperature so the startup vent is in open condition during the light of boiler it maintain the circulation of the steam inside the boiler and protect the super heater getting over temperature and also use for removing the air from the super heater which causes the hammering and water fluctuation inside the drum
Q.4 when we close boiler vent ?
Ans. During the cold start up of the boiler when the drum pressure reaches upto the 1.5 -2.5 kg/cm2 then we closed the drum air vent because of the all trapped air inside the super heater and water wall panel and other pressure part of the boiler removed through the air vent .
Q.5 what is use of boiler feed pump ?
Ans. Boiler feed pump is the heart of the boiler because of the it take the water from the deaerator and reaches the boiler steam drum against the steam drum pressure .
Q.6 Make of feed pump ?
Make of feed pump means that preparing the feed for start up , before start up of the feed pump insure that the its all interlock are in healthy condition or not , suppose that we starting the boiler feed pupm for taking the water in the boiler drum before it starting up we check its interlock is in healthy condition or not i.e instrumentation air is available or not , gland cooling water available or nor , it discharge valve is closed or not , its electrical supply should be one , deaerator level is in healthy condition or not ….etc
After insuring that we started the boiler feed pump for taking the water inside the boiler drum.
Q.7 capicity of boiler & working pressure?
Ans. Every boiler manufacturer make the boiler according the customer demand so that the every boiler have different capacity or working pressure . when boiler is In operating condition the tendency of boiler of water evaporation is called the boiler capacity and during this water evaporation which amount of pressure generated is called the that boiler working pressure.
Q.8 capicity of feed pump?
Ans. In power plant feed pump is used for the transferring the fluid one place to another . In power plant centrifugal pump are used for this propose. the tendency of boiler feed pump transferring the fluid at maximum r.p.m is called the capacity of the feed pump .
Q.9 how to convert pressure from PSI to kg/cm2
Ans. Kg/cm2 value = psi value x 0.0703070
Q.10 why we use pure (D.M water ) for boiler?
Ans. We use D.M water in boiler because of dissolved salts and minerals are successfully removed from the water . so this water is used for the getting high steam purity and also for pressure parts long life maintaining and also or power plant working is closed cycle so the we reutilized the condensate so the chemical consumption also reduced and saving the chemical cost also . for running economically of boiler we use D.M water .
Q.11when we do periodic inspection of boiler & why it done?
Ans. periodic inspection of boiler carried out because checking the boiler mounting and accessory are running in proper condition or not . boiler periodic inspection done because of the our boiler is running continuous running without breakdown .
Q.12 why we do hydraulic test of boiler?
Ans. Hydraulic test of boiler is carried out insuring the boiler pressure part withstand working pressure continuous or not. And also find the any leakage in boiler pressure part with the help of hydraulic test .this test is conducted at least once in a year or when the boiler is in shutdown condition or boiler is prepared for the cold startup. And also after each repairing job in the boiler pressure part .hydraulic test is normally carried out at a pressure equal to 1.5 times of the design pressure for a new boiler and 1.25 to 1.5 time of working pressure of old boiler. Hydraulic test is successful if pressure parts withstand the test pressure for 10 minutes without any leakge .
Q.13 some time steam pipe line hammering why ?
Ans . its due to air present in the pipe line when we take water through pipeline the the water comes in contact with this air and disturbed the water flow path and causes over pipeline hammering. And also resion behind it when we take water inside the steam drum when the boiler under hot start up economizer take sensible heat from the hot flue gas and heat up the feed water whenever at outlet of economizer the temperature is above the saturation temperature then the water starting boiling just outlet the economizer it also a causes of water hammering inside the boiler .
Q.14 what is use of economizer ?
Ans. Economizer is on of the important accessory of the boiler, economizer is a heat exchanger which is utilizes heat of exhaust flue gas from the boiler to increase the feed water temperature. Economizer helps the improving the efficiency of the boiler and also reduced the fuel consumption and make the boiler operation economical. it say that , by decreasing exhaust flue gas temperature by 16 degree Celsius , boiler efficiency increase by 1% . And also by increase the temperature by 6 degree Celsius boiler efficiency increase by 1%.
Q.15 why we give blow down of boiler ?
Ans. When the water is boiling inside the boiler and steam generation take place and after dissolve solids contained in the feed water remain in the boiler. if more solids are put in the fed water , they will concentrate and may eventually reach a level where their solubility in the water exceed and they deposit from the solution .above a certain level of concentration , these solids encourage foaming and causes carryover of water into the steam. These deposits also lead to scale formation inside the boiler .resulting in localized overheating and finally causing the boiler tube failure.
So it is very necessary to control these solids concentration inside the boiler drum this is achieving with the help of Blow Down when certain volume of water is blown off and automatically replaced by feed water so the maintaining of optimum level of total dissolved solids in the boiler water. blow down is necessary to protect the surface of the heat exchanger in the boiler .however blow down can be significant source of heat loss if improperly carried out .
Blow down benefits :-
Whenever we take the blow down of the steam boiler it control the significvant reduced the treatment and operational cost that include
- lower parameters costs
- less water make up consumption
- reduced the maintenance down time
- increase boiler life
- lower consumption of treatment chemicals
Q.16 how you false water level gauge glass & when?
Ans. When the gauge glass not showing the exact water level of boiler steam drum according the control room desk operator then we needed to flush the water gauge glass. Some time due to the sludge formation gauge glass not showing the correct reading so we needed to flush the gauge glass
Gauge glass are flushed the following method
Close the water cock and open the drain cock for some time
Close the drain cock and open the water cock
Water should retiring its normal working condition
Q.17what you do in the event of water shortage of boiler?
Ans. Water shortage occurring during the when water supply failed inside the boiler due to some problems like boiler tripped due to any interlock, or boiler feed pump failed due to some interlock like deaerator level low, or some other operational fault . and also a major condition when the plant is in black out condition when no electrical supply is not available for running the any auxiliary of the plant so the drum level goes down suddenly this condition is called the shortage of water inside the boiler.
Q.18 what you do in the event of boiler tube failure?
Ans. When the boiler is getting under the blackout condition then the water supply is failed to the boiler so that the water is not circulated through the tubes so the tube getting the over temperature and lack of water tube is coming under the starvation condition and tube get damaged due to higher temperature .
Q.19 what is the difference between FTB & WTB?
Ans. In FTB ( fire tube boiler ) hot flue gases are travelling inside the tube and water are outside the tube but in WTB (water tube boiler ) water inside the tube and hot flue gases are outside the tube . fire tube boiler are low pressure boiler and water tube boiler are the high pressure boiler .
Q.20 what is the use of safety valve in the boiler?
Ans. Whenever the boiler steam pressure is going above the safe limit working pressure then the safety valve release the exceeding pressure when the exceeding pressure comes under the safe working limit . Safety valve is just release the exceeding pressure protect the pressure part of the boiler from any damage
Q.21 which type of safety valve used in the boiler?
Ans. In high pressure boiler spring loaded safety valve is used .
Q.22 what is the use of fusible plug in the boiler?
Ans. Fusible plug is a safety device for the small type of boiler. it located above the furnace to prevent from any accident which happening due to the over temperature of the boiler. The fusible plug get fused and the fall into the boiler furnace and boiler stop working.
Q.23what is the steam trap?
Ans. Steam trap is used for the removing condensate from the steam and remaining the steam in superheated form.
Q.24 why we opened pipeline drain during the line charging of boiler ?
Ans. During line charging we opened line drain for the purpose of removing the condensate present in the line during shut down time and also evenly thermal expansion of the line and also protect the line from the hammering .
Q.25 what chemical is used in boiler ?
Ans. In boiler for the maintaining the feed water chemistry and the protect the boiler from the corrosion we used hydrazine in the deaerator and trisodium phosphate inside the steam drum and also use ammonia for ph booster in large boiler .
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