Fluidized Bed Boiler

The Fluidized Bed Combustion (FBC)

INTRODUCTION

A fluidized bed boiler utilizes a unique combustion chamber filled with granular material like sand or slag. This chamber ensures excellent mixing of fuel and air, leading to efficient combustion at lower temperatures. As a result, harmful emissions such as sulfur and nitrogen oxides are significantly reduced.

1- History and Development

The concept of fluidized bed combustion emerged in the 1960s, pioneered by Douglas Elliott. Its application for steam generation from biomass began in 1982 with a 10-ton/hour rice husk-fired boiler in India. Over time, fluidized bed boilers have evolved, replacing traditional systems like chain and stationary burners.

2- Types of Fluidized Bed Boilers

– Atmospheric Fluidized Bed Combustion (AFBC): Commonly known as bubbling fluidized beds, suitable for smaller capacities.

– Circulating Fluidized Bed Combustion (CFBC): Features high fuel efficiency and operates with smoke velocities of 4–6 m/s, ideal for capacities above 100 tons/hour.

– Pressurized Fluidized Bed Combustion (PFBC): Operates under high pressure and integrates gas and steam turbines for enhanced efficiency, designed for 70–350 MW capacities.

3- Key Applications

Fluidized bed boilers are widely used in industries like sugar, paper, food, and feed mills due to their ability to handle diverse fuels such as coal, biomass, and industrial waste.

4 Advantages of Fluidized Bed Boilers

Fuel Flexibility: Capable of burning high-ash coal, biomass, and industrial waste.
Lower Emissions: Meets strict environmental standards without expensive treatment systems.
Durability: Fewer moving parts reduce maintenance compared to traditional systems.

5- Disadvantages of Fluidized Bed Boilers

High Coke Fuels: Require additional components like tube beams, which may wear out quickly.
Large Combustion Chamber: Demands more space compared to other boiler types.
Fuel-Specific Design: Modifications are necessary when switching fuel types.

6- Why Choose Fluidized Bed Boilers?

Fluidized bed boilers offer unmatched efficiency, fuel versatility, and environmental compliance. Their ability to reduce emissions while providing cost-effective energy makes them indispensable in modern industrial applications.

By choosing fluidized bed boilers, industries can achieve sustainable energy solutions, reduced operational costs, and adherence to global environmental standards.

SPECIFICATION

+ Calculation & Design : according to ASME and TCVN

+ Fabrication : according to ASME and TCVN

+ Evaporation capacity : (10,000-300,000) kg/h

+ Design Pressure : (10-150) bar(g)

+ Fuel : Indonesia coal & Biomass

+ Boiler efficiency : 87%

FLUIDIEZED BED COMBUSTION LAYOUT

Principle:

The FBC system is built in a closed fuel feeding system consisting of:

– Fuel receiving hopper, Fuel lifting bucket elevator; Fuel Storage Silo

– From the Silo, the fuel will be transferred to the buffer silo by another conveyor system before feeding into the furnace.

After heating, the flue gas will keep going to the Economizer unit to recover the waste heat and change to the useful heat for the boiler.

At this time, the energy in the flue gas has nothing much to recover. it will be treated by a drying collector (what we call a bag filter) before going to the chimney and eventually into the atmosphere.