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Basic Controls For Boilers
MENTOR : PROFESSOR VIDITA TILVA
BY:
AASHEESH TANDON (12BIC044)
PAXAJ SHUKLA (12BIC056)
1. Introduction
How does a boiler works?
A boiler is a water containing vessel which transfers heat from a
fuel source (oi...
1. Introduction
The energy given up by the steam is sufficient to convert it back
into the form of water. When 100% of the...
1. Introduction
Since some processes can contaminate the steam, so it is not
always desirable to feed the condensate back ...
2. Basic type of boilers
 The two main types of boilers are:
• Firetube
Fire or hot gases are directed through the inside...
3. Why need boiler controls?
1. Increase uptime and availability
2. Reduce flue gas emissions
3. Maintain boiler safety
4....
4. Combustion control for boilers
 A combustion control system is broken down into :
(a) fuel control
(b) combustion air ...
4. Combustion control for boilers
 There are three general types of combustion control schemes used
today:
(a) series,
(b...
4(A). Hardware Used In Combustion Control
 (a) ON/OFF controls
 (b) Positioning systems
 (c) Metering control system
4.(B) Combustion Control Methods
Burner combustion control generally includes one or a combination of the
following method...
5. Feedwater Control For Boilers
 Feedwater control is the regulation of water to the boiler drum.
 Risks :
 If the lev...
5.(A) Components Affecting Drum Water Level
 steam bubbles
 Drum pressure
 ‘swell‘ : surge in water level as a result o...
5.(B) Single And Two Element Control
Systems
 Single Element :
 controls feed water flow based on drum level
 Response ...
5.(C) Three Element Control
 Used when :
 unstable feedwater system exists
 if large unpredictable steam demands are fr...
5. Application Chart For Drum Level
Control System
5.(C) Five And Seven Element Control
 Five element control is better than Three Element control in terms of :
 steam flo...
5. Feedwater Control for Boilers
 Advantages :
1. Multiple element feedwater control can help:
i. Faster response of syst...
5. Feedwater Control for Boilers
 Disadvantages :
1. Boilers require quick responding controls.
2. Level of the water in ...
6. Other Control Functions
 A. Furnace air and draft control
 B. Steam temperature control
 C. Steam pressure and load ...
THE END
Basic controls for boilers
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Basic controls for boilers

It deals with the two basic but important controls for a drum boiler - A) Combustion Control, B) Feed-Water Control

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Basic controls for boilers

  1. 1. Basic Controls For Boilers MENTOR : PROFESSOR VIDITA TILVA BY: AASHEESH TANDON (12BIC044) PAXAJ SHUKLA (12BIC056)
  2. 2. 1. Introduction How does a boiler works? A boiler is a water containing vessel which transfers heat from a fuel source (oil, gas or coal) into steam which is piped to a point where it can be used to run production equipment, to sterilize, to provide heat, to steam-clean, etc.
  3. 3. 1. Introduction The energy given up by the steam is sufficient to convert it back into the form of water. When 100% of the steam produced is returned to be reused, the system is called a closed system.
  4. 4. 1. Introduction Since some processes can contaminate the steam, so it is not always desirable to feed the condensate back into the boiler. A system that does not return the condensate is called an open system.
  5. 5. 2. Basic type of boilers  The two main types of boilers are: • Firetube Fire or hot gases are directed through the inside of tubes within the boiler shell which are surrounded by water. • Watertube Fire or hot gases are directed to and around the outside of tubes containing water, arranged in a vertical position.
  6. 6. 3. Why need boiler controls? 1. Increase uptime and availability 2. Reduce flue gas emissions 3. Maintain boiler safety 4. Control operating costs
  7. 7. 4. Combustion control for boilers  A combustion control system is broken down into : (a) fuel control (b) combustion air control
  8. 8. 4. Combustion control for boilers  There are three general types of combustion control schemes used today: (a) series, (b) parallel, & (c) series-parallel controls.
  9. 9. 4(A). Hardware Used In Combustion Control  (a) ON/OFF controls  (b) Positioning systems  (c) Metering control system
  10. 10. 4.(B) Combustion Control Methods Burner combustion control generally includes one or a combination of the following methods:-  Excess air regulation  Oxygen trim  Burner modulation  Air/Fuel cross-limiting  Total heat control
  11. 11. 5. Feedwater Control For Boilers  Feedwater control is the regulation of water to the boiler drum.  Risks :  If the level is too high, may interfere with the internal operation of internal devices in the boiler drum, such as - flooding of steam purification equipment can occur.  If the level is too low, reduction in efficiency of the treatment and recirculation function, undesired pressure build up, over heating of boiler coils/tubes.
  12. 12. 5.(A) Components Affecting Drum Water Level  steam bubbles  Drum pressure  ‘swell‘ : surge in water level as a result of the drum pressure decreasing  'shrink‘ : decrease in water level as result of drum pressure increasing
  13. 13. 5.(B) Single And Two Element Control Systems  Single Element :  controls feed water flow based on drum level  Response is very slow  Two Element :  uses steam flow changes as a feed forward signal  flow and level transmitters are summed by a computing relay  response is faster
  14. 14. 5.(C) Three Element Control  Used when :  unstable feedwater system exists  if large unpredictable steam demands are frequent
  15. 15. 5. Application Chart For Drum Level Control System
  16. 16. 5.(C) Five And Seven Element Control  Five element control is better than Three Element control in terms of :  steam flow measurement is temperature compensated, &  drum level measurement is pressure compensated.  Seven Element control is better than Five Element control in terms of :  Transmitters for blow down flow  Transmitters for soot blower flow
  17. 17. 5. Feedwater Control for Boilers  Advantages : 1. Multiple element feedwater control can help: i. Faster response of systems. ii. More accurate control. iii. Maximum system stability. 2. Metering control system maintains combustion efficiency over wide load changes and over long period of time 3. Parallel combustion control can be used in any size of boilers
  18. 18. 5. Feedwater Control for Boilers  Disadvantages : 1. Boilers require quick responding controls. 2. Level of the water in the boiler must be kept above 50% of height.
  19. 19. 6. Other Control Functions  A. Furnace air and draft control  B. Steam temperature control  C. Steam pressure and load control
  20. 20. THE END

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