1. High Pressure Boilers & Accessories
: POWER PLANT ENGINEERING
High Pressure Boilers & Accessories
Prepared By
Prof. Jagdish S.Talpada
Assistant Professor,
Mechanical Engineering Department,
DJMIT, Mogar

2. prepared by Prof. Jagdish S. Talpada
LECTURE - 1
prepared by Prof. Jagdish S. Talpada

3. prepared by Prof. Jagdish S. Talpada
Industrial Boilers
Steam generators
Closed vessels
made of steel and
used for generation of steam
vaporizing water
combustion of fuels
eg. coal,coke,oil,wood,saw dust and begesse etc.
Steam used for producing power,for industrial process work or for heating proposes.
prepared by Prof. Jagdish S. Talpada

4. Requirements of a Perfect Steam Boilers
Should be absolutely reliable,capable of producing maximum steam at required pressure for minimum of fuel consumption,with minimum attention and minimum initial cost and operating cost.
Simple constructions
Quick starting from cold
Strong enough against temp. stress & strains
Well design combustion chamber
Less floor area, space & light weight
Best gauges,safety valves and other mountings
Easily accessible for inspection,cleaning and repairs
prepared by Prof. Jagdish S. Talpada

5. Classification of Steam Boilers
Vertical or Horizontal
Stationary(Power plant,industrial,central heating and combined power and heating boilers.),Portable,Locomotive or Marine
Internally Fired or Externally Fired (Lancashire and Locomotive Boilers)
Solid,Liquid or Gas Fired
Fire(Smoke)Tube:Water is outside the tubes while the hot gases are inside the tubes eg.Vertical,Cochran,Lancashire,Cornish,Locomotives,etc) or Water Tube: Contain a large number of small tubes through which water circulates,the fire and hot gases being outside of the tubes.eg.Babcock and Wilcox, Stirling and High pressure Boilers etc.)
prepared by Prof. Jagdish S. Talpada

6. prepared by Prof. Jagdish S. Talpada
Vertical Boilers
Used in small factories,small water supply plants,cranes,excavators,winch engines in mines and on sites of temporary nature such as construction work etc.
Required minimum floor space,not required elaborate foundations,and is portable.
Cheap,easy to start but inefficient due to large wastage of fuel and less heating surface.
Vertical Boilers are:Simple(having one to three cross tubes), fire tubes and water tubes types.
prepared by Prof. Jagdish S. Talpada

7. Simple Cross tube vertical boiler
consists of a cylindrical shell surrounding a cylindrical fire box.
heating surface is about 8-10 times the grate area.
50% efficiency
prepared by Prof. Jagdish S. Talpada

8. prepared by Prof. Jagdish S. Talpada
Cochran Boiler
It is well design of a Vertical multitubular fire tube boiler
Improvement over the simple vertical boiler as it provides greater heating surface.
Total heating surface area is about times the grate area
Efficiency 70-75%
Ranges from 1m dia.X2m high,evaporation 20kg/hr to 3m dia X6m high,evaporation 3000kg/hr.
prepared by Prof. Jagdish S. Talpada

9. prepared by Prof. Jagdish S. Talpada
Cochran Boiler contd….
prepared by Prof. Jagdish S. Talpada

10. prepared by Prof. Jagdish S. Talpada
Lancashire Boiler
Is horizontal smoke tube boiler size range from a shell 2m diaX6m long to 3m diaX10m long
Working pressure range are up to 20kgf/cm2
Ratio of heating surface to grate area is 24-30
Efficiency is about 56% without economizer and 75% with economizer.
Similar to Cornish boiler,in Lancashire Boiler two flue tubes but in Cornish boiler only one flue tubes are there.
prepared by Prof. Jagdish S. Talpada

11. prepared by Prof. Jagdish S. Talpada
LECTURE - 2
prepared by Prof. Jagdish S. Talpada

12. Lancashire Boiler contd……
prepared by Prof. Jagdish S. Talpada

13. Lancashire Boiler contd……
prepared by Prof. Jagdish S. Talpada

14. prepared by Prof. Jagdish S. Talpada
Locomotive Boiler
Is an internally fired multitubular fire tube boiler
prepared by Prof. Jagdish S. Talpada

15. Babcock and Wilcox water tube Boiler
Water tube boiler having lager pressure ranges and larger sizes.
Three main parts, steam and water drum,water tubes and furnace.
prepared by Prof. Jagdish S. Talpada

16. prepared by Prof. Jagdish S. Talpada
Stirling Boiler
Example of water tube boiler where bent tube are used instead of straight tube which are used in Babcock and Wilcox boiler
prepared by Prof. Jagdish S. Talpada

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LECTURE - 3
prepared by Prof. Jagdish S. Talpada

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High Pressure Boilers
Two types- Natural circulation & Forced circulation Boilers
prepared by Prof. Jagdish S. Talpada

19. High Pressure Boilers contd………
La-Mont Boiler( Forced circulation Boiler)
prepared by Prof. Jagdish S. Talpada

20. Once-Through Forced Circulation Boiler
Does not required a steam and water drum,saving in weight
Supercritical Pressure Boiler
Two types- Benson and Ramzin
prepared by Prof. Jagdish S. Talpada

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Ramzin Boiler
prepared by Prof. Jagdish S. Talpada

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Loeffler Boiler
Indirect heating is combined with forced circulation
prepared by Prof. Jagdish S. Talpada

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Velox boiler
Fire tube forced circulation Boiler
prepared by Prof. Jagdish S. Talpada

24. prepared by Prof. Jagdish S. Talpada
LECTURE - 4
prepared by Prof. Jagdish S. Talpada

25. Fire tubes Vs water tubes Boilers
Fire tubes boilers has a large volume of water,therefore more flexible and can meet the sudden demand of steam without much drop of pressure.
Fire tubes boiler is rigid and of simple mechanical construction,so greater reliability and low in first cost.
Fire tube boilers can be made in smallest sizes therefore simple to fabricate and transport, occupies less floor space but more height.
Due to mostly externally fired water tubes boiler so furnace can be altered considerably to meet the fuel requirements.
Water tubes boilers are more readily accessible for cleaning,inspection and repairs,compared to the fire tube boilers.
Modern trend is in the favors of water tube boiler due to continuous increase in capacities and steam pressures.
prepared by Prof. Jagdish S. Talpada

26. Boiler Mountings and Accessories
Fitting and devices which are necessary for the safety and control are knows as boiler mountings
Fitting or devices which are provided to increase the efficiency of the boiler and help in the smooth working of the plant are knows as boiler accessories.
Fittings which are essential from the safety point of view are as follows,
Water level indicators
Safety valves
Combined high steam and low water safety valve
Fusible plug
prepared by Prof. Jagdish S. Talpada

27. Boiler Mountings and Accessories contd….
Fittings which are essential from the control point of view are as follows,
Pressure gauge
Junction or stop valve
Feed check valve
Blow-off cock
Man hole and Mud Box
The important accessories are
Superheater
Economiser
Air-preheater
Feed pump or injector
prepared by Prof. Jagdish S. Talpada