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Boilers
8/4/2019 Boilers by 09 ME 126
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Introduction
Type of boilers
Assessment of boiler
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What is a Boiler?
Introduction
• Vessel that heats water to becomehot water or steam
• At atmospheric pressure watervolume increases 1,600 times
• Hot water or steam used to transferheat to a process
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Introduction
Type of boilers
Assessment of a boiler
Boiler
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Types of Boilers
1.Flammable boiler2.Inflammable boiler
What Type of Boilers Are There?
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Flammable boiler
• The boiler is industrial boiler, which
is based on coal, heavy oil, light oil
or flammable gas as fuel,
steam water.
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Inflammable Boilers
• The boilers in which the process
of combustionof inflammable materials
producing heat.
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Type of Boilers
1. Fire Tube Boiler
•
Relatively small steamcapacities (12,000kg/hour)
• Low to medium steampressures (18 kg/cm2)
• Operates with oil, gasor solid fuels
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Type of Boilers
Water Tube Boiler
• Used for high steamdemand and pressure
requirements
• Capacity range of 4,500 – 120,000 kg/hour
• Combustion efficiencyenhanced by induceddraft provisions
• Lower tolerance forwater quality and needs
water treatment plant
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Introduction
Type of boilers
Assessment of a boiler
Training Agenda: Boiler
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Assessment of a Boiler
1. Boiler performance
• Causes of poor boiler performance-Poor combustion
-Heat transfer surface fouling
-Poor operation and maintenance
• Heat balance: identify heat losses
• Boiler efficiency: determinedeviation from best efficiency
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Assessment of a Boiler
Heat BalanceAn energy flow diagram describes geographicallyhow energy is transformed from fuel into useful
energy, heat and losses StochiometricExcess AirUn burnt
FUEL INPUT STEAMOUTPUT
Stack Gas
Ash and Un-burnt partsof Fuel in AshBlowDownConvection &Radiation
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Assessment of a Boiler
Boiler Efficiency: Direct Method
Boiler efficiency () =Heat Input
Heat Outputx 100
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Assessment of a Boiler
• Quality of steam depend on water
treatment to control• Steam purity
• Deposits
• Corrosion
• Efficient heat transfer only if boilerwater is free from deposit-formingsolids
3. Boiler Feed Water Treatment
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Assessment of a Boiler
Deposit control
•
To avoid efficiency losses andreduced heat transfer
• Hardness salts of calcium andmagnesium
• Alkaline hardness: removed by boiling
• Non-alkaline: difficult to remove
• Silica forms hard silica scales
Boiler Feed Water Treatment
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Assessment of a Boiler
• Chemicals added to boiler toprevent scale
•Different chemicals fordifferent water type
Boiler Feed Water Treatment
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Boilers
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