The Outline of TSK FBI
Fluidized bed incineration (FBI) system will be applied in the sewage sludge treatment facilities (STF). Tsukishima Kikai Co., Ltd (TSK; in Tokyo) has abundant experience, know-how and combustion technologies as a leading company in Sludge Treatment Incineration Plant. Main features of TSK's FBI system are as follows.
- (1) Features of the Applicant Combustion (FBI) System
The sludge feeder continuously feeds dewatered/dried sludge to the fluidized bed zone. The temperature of free board zone is controlled at 850°C, and the fluidized bed zone temperature is controlled at around 650 to 750°C. Under such condition, stable and complete combustion in a short time occurs as the supplied sludge diffusing evenly throughout the zone contacts the combustion air supplied from the diffusion pipe. Combustion temperature and retention time for the combustion gas and ash are maintained at the free board and discharged as flue gas by the fluidized bed incineration furnace after complete combustion.- Complete combustion is attained with simultaneous drying and incineration inside the high temperature fluidized bed zone.
- The large heat capacity of the fluidized sand makes stable operation even if the volume or the properties of the sludge may change.
- Ideal fluidization is achieved with cone-shaped fluidized bed zone.
- Foreign materials and incombustibles can be extracted from the bottom of the incinerator.
- Odor is completely decomposed by high temperature.
- Operation can be easily stopped and restarted.
- The volatile matters in ash account for less than 1%
- As for Dioxin, adequate distribution of combustion air, high temperature over 850°C and retention time over 2 seconds, reduces its generation. For SO2, HCl and dust are treated to be lower than the target emission limits.
- (2) Abundant Experiences and Large Unit Capacity
TSK, as a leading supplier in Japan, has accumulated a lot of know-how and abundant experiences in designing, constructing and operating Fluidized Bed Incinerators for Sewage Sludge Treatment Facility, and standardized up to a large-sized incinerator of 350T/D. - (3) Reliability and Long Term Service Life
Applicant has proven record for long term Service Life of Fluidized Bed Incineration system, for example, plant built in 1978 is still in service with 320days per year operation. - (4) Efficient Flue Gas Cleaning System
Various methods must be applied to remove the pollutants generated by combustion of sewage sludge. Wet scrubbers are very effective, reliable and economical in removing HCl/SOx.
TSK applied Wet scrubbing system adding NaOH as flue gas cleaning system to meet the required regulation value.
Schematic Flow of FBI
