Key Features:
- Uses a steam circulating pump to force circulation.
- Employs superheated steam instead of water for evaporation.
- Works efficiently in high-pressure operations (100-140 bar).
Parts of Loeffler Boiler
The Loeffler boiler consists of the following essential components:
| Part | Function |
|---|---|
| Feed Pump | Supplies feed water to the boiler. |
| Economizer | Preheats the feed water using flue gases. |
| Evaporator | Converts water into saturated steam. |
| Radiant Superheater | Uses radiant heat from flue gases to superheat steam. |
| Convection Superheater | Further heats steam using convective heat transfer. |
| Steam Circulating Pump | Forces circulation of steam inside the boiler. |
| Steam Outlet | Delivers superheated steam to the prime mover. |
| Flue Gas Outlet | Removes exhaust gases after heat exchange. |
Working Principle of Loeffler Boiler
The Loeffler boiler operates on the principle of superheating steam using heat energy from flue gases instead of relying on water circulation.
Step-by-Step Working Process:
- Feed Water Supply: Water is supplied to the boiler through the feed pump. It passes through the economizer, where it absorbs heat from flue gases.
- Steam Generation: Only 30% of the water is converted into steam in the evaporator. The remaining 70% of the steam is superheated using a steam circulating pump.
- Superheating Process: The saturated steam first passes through the radiant superheater. It then moves to the convection superheater to achieve further heating.
- Steam to Prime Mover: The superheated steam is sent to the prime mover (turbine) for power generation. After expansion in the turbine, the exhaust steam is reused for heating.
- Flue Gas Removal: The remaining flue gases exit through the chimney, releasing heat in the economizer.
Key Working Principle
Instead of using water circulation, the Loeffler boiler reuses exhaust steam to generate more superheated steam, making it highly efficient for power generation.
Advantages of Loeffler Boiler
The Loeffler boiler is widely used due to its unique advantages in high-pressure applications.
- Prevention of Salt & Scale Deposition – Since steam (not water) is circulated, salt accumulation is minimized.
- High Thermal Efficiency – Reuses exhaust steam for better fuel efficiency.
- Suitable for High-Pressure Operations – Operates at 100-140 bar with superheated steam.
- Reduced Water Requirement – Uses only 30% water, making it ideal for areas with limited water availability.
- Improved Heat Transfer – Uses both radiation and convection superheaters for effective steam generation.
Applications of Loeffler Boiler
The Loeffler boiler is commonly used in power plants and industrial applications where high-pressure steam is required.
- Power Generation Plants – Used in thermal power plants for electricity production.
- Industrial Steam Generation – Applied in chemical industries for process heating.
- Marine Applications – Used in naval and cargo ships for propulsion systems.
- High-Pressure Steam Requirements – Ideal for plants operating under 100+ bar pressure.
Disadvantages of Loeffler Boiler
Despite its advantages, the Loeffler boiler has some limitations.
- High Initial Cost – Complex design makes it expensive to manufacture.
- Requires Skilled Maintenance – Needs trained personnel for operation.
- Large Size & Space Requirement – Occupies more space due to multiple components.
- Pump Power Consumption – The steam circulating pump requires extra power.
Conclusion
The Loeffler Boiler is an advanced high-pressure water tube boiler that eliminates scale formation by using superheated steam circulation. It is highly efficient, reliable, and suitable for large-scale power generation.