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Boilers

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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 

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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

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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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