Updated: July 2002

1. Outline of Equipment

The Circulating Fluidized Bed Incinerator is a next-generation incinerator that can effectively satisfy the diverse demands made of sewage sludge incinerators. For instance, it can accommodate high-calorie sludge, manifold sludge properties, and load changes, and incinerate sludge mixed with other waste materials.
By operating at a high superficial velocity of 4.0-8.0 m/s, the Circulating Fluidized Bed Incinerator performs the role of mixing and stirring sludge with the bed material, sand, as well as the role of a heating medium. The incinerator is composed of a riser (the combustion chamber), a cyclone that separates the sand discharged to outside the incinerator from the combustion gas, and a downcomer that returns the separated sand to the riser. For high-calorie waste material, a heat exchanger is built into the bottom of the downcomer, allowing heat to be recovered inside the incinerator.

Figure Outline of Equipment

2. Features

(1) Stable Combustion
Inside the Circulating Fluidized Bed Incinerator, a large volume of heat circulates, with sand as its heating medium. As a result, the temperature inside the incinerator is uniform, temperature control (combustion control) is easy, and stable combustion can be achieved for a wide range of sludge properties, for mixed incineration with other waste materials such as remained screenings or grit, and for load changes.
(2) Low Energy Consumption
The blower required to circulate the sand operates with a low discharge pressure. As a result, blower power can be reduced to 60-70% of that used by Bubbling Fluidized Bed Incinerators.
(3)Heat Recovery Inside Incinerator
An external heat exchanger (a fluidized-bed heat exchanger) is used, permitting heat recovery inside the incinerator. An external heat exchanger also allows the amount of heat recovered to be freely controlled. It is thus an effective mechanism for controlling the combustion of self-combustible sludge (high-calorie sludge).
(4)High-Intensity Combustion
In the Circulating Fluidized Bed Incinerator's superficial velocity range of 4.0-8.0 m/s, the relative speed (slip speed) of gas and particles is maximized, as is their contact efficiency. As a result, high-intensity combustion is possible, and incinerator size has been reduced, saving on space.
(5) Desulfurization Inside Incinerator
Spraying slaked lime into the furnace enables desulfurization inside the Incinerator. The Circulating Fluidized Bed Incinerator provides excellent solid-gas contact, so that a desulfurization efficiency of around 90% can be expected.

3. Performance

(in Unmixed Sludge Incineration)

4. Applications

Incineration of waste materials such as dewatered sludge, dried sludge and RDF, either individually or mixed with other waste materials.

5. Miscellaneous

<Owned Experimental Incinerator>
Sludge incineration: 8.0 t-cake/d
RDF incineration: 5.0 t-RDF/d (with boiler equipment attached)
Location: Osaka (our company's test center)