What is fluidised bed combustion system?

What is fluidised bed combustion system?

Fluidized-bed combustion (FBC) uses a mixture of particles suspended in an upward flowing airstream, which combine to exhibit fluid-like properties. Combustion takes place in the bed with very intense mixing of gases and solids, high heat transfer to the furnace, and a low combustion temperature.

Where is fluidized-bed combustion used?

Advantages and Dis-advantages of Fluidized Bed Combustion FBC is being used exhaustively these days in all major power stations all over the globe, owing to numerous advantages that it offers over the other pre-dominant methods of combustion. Few of those are: High thermal efficiency.

How does a fluidised bed work?

Typically, pressurized gas or liquid enters the fluidised bed vessel through numerous holes via a plate known as a distributor plate, located at the bottom of the fluidised bed. The fluid flows upward through the bed, causing the solid particles to be suspended.

What is fluidized-bed combustion of coal?

In fluidized-bed combustion, any fuel, e.g. coal, oil or gas, is dispersed and burned in a fluidized bed of inert particles. In most applications the temperature of the bed is maintained in the range 750–1000°C so that combustion of the fuel is substantially completed but particle sintering is prevented.

What are the advantages of fluidized-bed combustion?

FBC boilers can burn fuel with a combustion efficiency of over 95% irrespective of ash content. FBC boilers can operate with overall efficiency of 84% (plus or minus 2%). High heat transfer rate over a small heat transfer area immersed in the bed result in overall size reduction of the boiler.

What are the types of fluidized-bed boiler?

6.3 Types of Fluidised Bed Combustion Boilers 1. Atmospheric classic Fluidised Bed Combustion System (AFBC) 2. Atmospheric circulating (fast) Fluidised Bed Combustion system(CFBC) 3. Pressurised Fluidised Bed Combustion System (PFBC).

What are the types of fluidized bed boiler?

What is fluidization process?

Fluidization is defined as a method to keep solid particles floating in an upward direction (Figure 5) in a flow of gas or liquid. In freezing, fluidization occurs when particles of a similar shape and size are subjected to an upward stream of low-temperature air.

How does a fluidized bed incinerator work?

What is a Fluidized Bed Incinerator? A Fluidized Bed Incinerator uses a bed of hot sand or other granular material to transfer heat directly to waste. It is commonly used for destroying municipal sludge.

What are the disadvantages of fluidized-bed combustion?

Disadvantages Of Fluidized Bed Combustion: It has to be maintained at a high value because there is a continuous requirement of high-pressure air for supporting the bed. 2) Due to the requirement of continuous high-pressure air, the cost of the auxiliary units of the plant increases.

What are the advantages of the fluidized-bed combustion system over the fixed bed and the suspension firing systems?

Circulating fluidized-bed combustion technology has a number of advantages over BFBC technology including [19]: Improved combustion efficiency and sulfur retention due to the use of finer particles, turbulent gas-particle mixing, and a high recycle rate. Smaller bed area due to the use of high fluidizing velocities.

What is fluidized in a fluidized-bed reactor?

Fluidized-bed reactors (FBR) are the most popular reactor configurations employed for reactions involving solid reactants. In the FBR, a fluidization medium (gas or liquid) is passed through the bed of solid reactants at high enough velocities to suspend the solid and cause it to behave like a fluid.