Sewage treatment process separate and concentrate a large volume of sludge, giving rise to the serious problem of sludge treatment. Incineration is one of the best methods for reducing the volume of this sludge and sanitating it.
Among incineration method, the fluidized bed incineration system is attracting special attention due to its profitable features including high combustion efficiency and easy maintenance.
Kobe Steel is able to offer fluidized bed incineration system that satisfy customer's needs through their total engineering and know-how.

[Features]

1) Due to fluid movement of quarts sand, the sludge cake delivered to the furnace
   can be burnt quickly and completely.

2) Since no mechanically moving parts are present in the furnace, the simple inner 
   structure offers easy maintenance.

3) The exhaust gas is at a temperature of approximately 800 deg.C, high enough
   to completely destroy odor sources.

4) Since quartz sand retains heat well, batch operation can easily be performed.

5) Two-step combustion prevents the system from emitting NOx.

6) The incinerator also allow combustion of refuse and screened debris togethe
   with sludge.

Incinerator configuration

The diameter of the fluidized bed section of the incinerator has been optimized to insure a gas velocity of 0.8 to 1.0 m/s, adequate to create movement of the sand particles and provide efficient combustion. The freeboard diameter is wider than the fluidized bed section to provide a longer gas
residence time in order to insure that the gas is completely combusted.

Orifice plate

The air orifice plate is comprised of T-shaped air-regulating nozzles and panel-shaped air-regulated plates, both construction out heat-resistant steel. These are installed in the incinerator in a free condition.

Refractory

The incinerator structure is composed of three-layers comprised of fire-brick, heat-insulating brick and heat-insulating castable. Fan shaped fire-brick is used which effectively prevents the bricks from falling out of the structure.

[Energy saving system]

Steam dryer system

- This system used a steam dryer to dry the sludge cake indirectly.  The steam 
  is generated by the heat from the exhaust-gas boiler.

- High thermal efficiency can be realized.

Hot-air dryer system

- This system dries the sludge cake directly by directing hot air pre-heated in
  the heat exchangers against the sludge cake using a rotary kiln dryer which 
  remain in contact with the sludge cake during drying operation.

- Since no boiler is needed, maintenance is relatively easy.

Fig.l.l Hot air recovery system

Fig.1.2 Steam dryer system

Fig.2 Schematic of Kobe Steel's flidized bed sewage sludge incinerator