Priming:
1. What do you mean by
the term Priming?
Priming
means carryover of water particle in the steam
2. What are the reasons
for Priming?
Reasons for
priming;
- Improper design of Boiler and steam drum
- Maintaining high drum level
- Boiler load fluctuation
- Sudden load raise due to steam demand
- Foaming in feed water
- Miss operation of Boiler
- Sudden lifting of Boiler safety valve or start up vent CV
- More impurities in Boiler water
3. What are the impacts
of Priming?
Impacts of Priming;
- Lower steam efficiency
- Water hammering
- Super heater coil failure due to thermal shock
- Turbine high vibration & blade failure
How do you avoid
priming in Boilers?
Priming can
be avoided by;
- Proper operation of boiler
- Maintaining drum level in between 45 to 55%
- Avoiding foaming
- Avoiding sudden load fluctuation
- Proper designing of Boiler
Carryover:
What do you mean by the
term carryover?
Carryover is
the carryover of solid, liquid & gaseous contaminants with water and steam
leaving the drum due to incomplete separation of water and steam in steam drum.
What are the major
reasons for carryover?
Reasons
for carryover;
- Defects in steam and water separators
- Foaming
- Boiler load fluctuation
- Higher drum level
- Boiler steam drum construction defects
What are the effects of
carryover on Boiler components?
Contamination
in steam leads to deposition of solid scale on Super heater coils & control
and regulating valves.
Foaming:
What do you mean by the
term foaming?
Foaming is the formation of unbroken bubbles on the surface
of the boiler water inside the boiler drum.
The bubbles may be in thin layer with few bubbles overlying
each other or it may build up throughout the steam space.
What are
the reasons for foaming?
- High suspended solid concentration
- High alkalinity concentration
- High dissolved solid concentrations in the boiler water
- Oil and organic contaminants in the boiler water
- High impurities
- High dosage of chemicals
- High water level
How do
you avoid foaming?
- Timely blow down & maintaining desired water quality
- Maintaining constant load on Boiler
- Avoiding high water level
No comments:
Post a Comment
Hi all,
This article is written based on practical experience..If liked, share with others, or any suggestions leave in comment box.