An economiser is a heat exchanger that recovers waste heat from the flue gases (exhaust) of the boiler and uses it to preheat the feed water entering the boiler.
Main Benefits of Using a Boiler
Economiser
1.
🔥 Improved Boiler
Efficiency
o
Recovers
heat from exhaust gases.
o
Increases
the overall thermal efficiency of the boiler by 5–8%.
2.
💰 Fuel Savings
o
Reduces
fuel consumption by preheating the water.
o
Saves
fuel costs (coal, gas, diesel, or biomass).
3.
🌱 Reduced Emissions
o
Lower
fuel use means less CO₂ and NOx emissions.
o
Helps
meet environmental regulations.
4.
💦 Preheats Feedwater
o
Reduces
the temperature difference between the feedwater and boiler water.
o
Lowers
thermal stress on boiler parts, increasing their lifespan.
5.
🛠️ Extended Boiler
Life
o
Smooth
temperature changes reduce metal fatigue and corrosion risk.
o
Increases
durability of the boiler tubes.
6.
📉 Reduced Operating
Cost
o
Less
fuel + less maintenance = lower OPEX.
7.
⏱️ Faster Steam
Generation
o
Preheated
water boils faster.
o
Useful
in applications requiring quick startup.
Working
Principle of a Boiler Economiser
1. Hot
flue gases exit the boiler:
o When fuel is burned in a
boiler (like gas, oil, coal, or biomass), it produces hot gases that exit
through the chimney
or stack.
o These gases can be 300–400°C
or higher, and much of this heat is usually wasted.
2. Flue
gases pass through the economiser:
o Instead of going directly
outside, the flue gases pass through the economiser,
which contains a series of metal tubes or coils.
o Inside these tubes is cold
feedwater coming into the boiler.
3.
Heat transfer occurs:
o The hot flue gases transfer
heat to the cold feed water through the metal surfaces of the
economiser.
o As a result, the feed water
temperature rises
before entering the boiler drum.
4. Preheated
water enters the boiler:
o Because the feedwater is
already heated, the boiler needs to use less fuel to
convert it into steam.
o This improves
thermal efficiency and saves fuel costs.
⚙️
Simple
Diagram (Text)-How to work Economiser?
CSS Flue gases ---> [ECONOMISER] ---> Chimney↑
Cold feedwater in↓
Preheated water to boiler
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