Updated: July 2002

1. Objective

The fluidized bed incinerator is designed to treat sewage sludge or industrial highly efficiently and completely and freely construct an energy saving system or energy creating system by making use of combustion waste heat for recovery.
Ash after burning is particles containing no unburnt combustibles, uniform and stable in quality. It can be effectively used to manufacture interlocking blocks, etc.

2. Performance Characteristics

- Heat recovery is easy and energy is saved or created freely.
- Reaction and heat transfer speed is high and the fluidized bed provides liquid characteristics, which ensure high automation and labor saving.
- Burnt ash is stable and safe allowing its effective use.
- Burning air ratio is 1.3 allowing complete burning sufficiently. As a result, only a very small amount of thermal NOX, etc. is generated.
- Exhaust gas generates no organic smell and requires no deodorizing unit.
- Burning efficiency is very high and no unburnt combustibles remain.

3. Features

1) Proper fluidized bed area
The fluidized bed area is calculated based on the heat load obtained from the heat balance and material balance.
2) Proper fluidized bed materials
Particle size of the silica sand is calculated from the terminal velocity obtained by multiplying the calculated space rate by a specific coefficient to select fluidized bed materials with proper particle size distribution.
3) Proper air distribution force
Special distribution nozzles with proper ventilating resistance are used to distribute the fluidizing air uniformly, in order to maintain satisfactory fluidizing condition throughout the fluidized bed.
4) Proper freeboard height
Proper height of the freeboard is determined depending on the object to be burnt so that the gas flux in the fluidized bed is a flow rising vertically throughout the surface in order to form a satisfactory fluidized bed, the fluidized bed material is protected from being carried over the incinerator and burning is completed in the incinerator if the combustion should be done in the freeboard.

4. Principle

Making use of the high heat transfer speed and large heat capacity of the fluidized bed, even objects of high water content can be dried, decomposed, and burnt almost instantaneously. In order to maximize the features of the fluidized bed incinerator, a satisfactory fluidized bed of such materials as to allow active and entirely uniform movement is formed and its effective required volume is secured in order to complete most of burning reaction of the object to be burnt and auxiliary fuel within the fluidized bed and restrict the burning of the "freeboard" to improve the burning efficiency. As a result, generation of thermal NOX can be restricted.

5. Figure

6. Areas of application

Municipal sewage treatment plant
Nightsoil treatment plant
Municipal waste incineration plant
Refuse treatment plant
Pulp and paper industry
Food processing industry
Pharmaceutical manufacturing industry
Organic chemical industrial product manufacturing industry
Beverage manufacturing industry
Pig breeding industry
Automotive and related manufacturing industry
Textile and related manufacturing industry

7. Example

Municipal sewage treatment plant: Primary sludge + activated sludge dewatered cake.
Nightsoil treatment plant: Digested sludge dewatered cake
Pulp and paper industry: Pulp waste water + sludge
Pharmaceutical industry: Waste toxic cake
Textile industry: Wool scouring wastewater sludge
Organic chemical industry: Waste oil, oligomer, etc.
Food processing industry: Diatomaceous earth cake
Pig breeding industry: Pig excrement