Thermal Power plant interview questions and answer
What are boiler mountings?
boiler mounting are mounted on the boiler itself and mandatory required for safe and proper operation of boiler
1.water level indicator
4. Blowdown valve
5.Feed Check valve
6.Main steam Stop valve
what are boiler accessories?
Boiler accessories are components that are attached to boiler and used for working of boiler and increasing its efficiency
3. Air preheater
5. super heater
6.Ash handling system
what type of boiler does not need steam drum?
Super critical Boiler
Why it is unsafe to have high water condition in drum?
High Drum Level does not allow efficient steam water separation and makes water to carry over with steam to turbine.
What are the causes for boiler tube failure?
Due to long term overheating due to scales and deposits formed on the outer surface of tubes
Short term overheating , occurs due to flow restriction in the tube
Thermal stress and shock , occurs due to frequent start and stops
Erosion, occurs due to coal , oil, ash corrosion
Creep occurs due to constant stress of material at high temperature
Why boiler is purged every time before starting?
To remove any left over fuel in boiler which leads to explosion
What are the uses of oil firing?
1.warming up of boiler due to cold start up
2.increase the furnace core temperature to switch to coal firing
3. Stabilizing flame when interruption occurs to coal firing
4.Useful during low load operation
What is the pressure and temperature of super critical boiler?
Boiler operating pressure is more than critical pressure (221.2 bar and 375 deg temp) is called super critical boiler. At this point both steam and water have same density.
how to find incomplete combustion in boiler
high carbon oxide content at flue gas at exit
The efficiency of Rankine cycle is in the range of
On which factor does calorific valve of coal depend upon?
What is Thermal Energy?
The ratio of heat energy to the turbine to heat of coal combustion