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Industrial Boilers

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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 ... – PowerPoint PPT presentation

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Title: Industrial Boilers


1
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.

2
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

3
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)TubeWater 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.)

4
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 areSimple(having one to three
    cross tubes), fire tubes and water tubes types.

5
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

6
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 10-25 times
    the grate area
  • Efficiency 70-75
  • Ranges from 1m dia.X2m high,evaporation 20kg/hr
    to 3m dia X6m high,evaporation 3000kg/hr.

7
Cochran Boiler contd.
8
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.

9
Lancashire Boiler contd
10
Lancashire Boiler contd
11
Locomotive Boiler
  • Is an internally fired multitubular fire tube
    boiler

12
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.

13
Stirling Boiler
  • Example of water tube boiler where bent tube are
    used instead of straight tube which are used in
    Babcock and Wilcox boiler

14
High Pressure Boilers
  • Two types- Natural circulation Forced
    circulation Boilers

15
High Pressure Boilers contd
  • La-Mont Boiler( Forced circulation Boiler)

16
Once-Through Forced Circulation Boiler
  • Does not required a steam and water drum,saving
    in weight
  • Supercritical Pressure Boiler
  • Two types- Benson and Ramzin

17
Ramzin Boiler
18
Loeffler Boiler
  • Indirect heating is combined with forced
    circulation

19
Velox boiler
  • Fire tube forced circulation Boiler

20
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.

21
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

22
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
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