Kawasaki
Internal Circulation Fluidized Bed Boiler© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved1

Standing Position ofInternal Circulation Fluidized Bed Boiler
BFBCFB●Small ～ Middle size
●Applicable for low
heating value fuel (Papersludge, wood chip etc.)●Low height boiler●Middle ～ Large size
●Co-firing of coal andother recycle fuel●Bed temp. control byash circulation●Tower type boiler

Internal Circulation Fluidized Bed Boiler
HybridType© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved●Small ～ Middle size（50～150t/h）●Bed temp. control by BM circulation●Applicable for low heating value fuel●Applicable for high heating value fuel●Applicable for corrosive fuel●Same boiler height with BFB2Combustion System ofInternal Circulation Fluidized Bed Boiler
Tertiary air
Fuel
Freeboard
Doublepartition wall
Secondary air
Embedded
Evaporator

EmbeddedSuperheater
Hear recoveringcell

Combustion
cell

Fluidizing air
for heat recovering cell

Flow direction of
bed material

Fluidizing airfor circulating cell
Fluidizing airfor combustion cell
© 2013 Kawasaki Heavy Industries, Ltd. All Rights ReservedHear recoveringcell

Incombustible

Circulating cell3

Fluidized bed and furnace
Fuel Supply

Freeboard

1.Large furnace
Three(3)“T”(retentionTime,highTemp.,
Turbulence) is important for complete combustion
without emission of dioxin. Furnace is designed tohave large volume to keep long retention time.

2.Tertiary air nozzle and two-stage nose
Large two-stage nose is provided for turbulence
and mixture of flue gas after blowing tertiary
combustion air.

DoublePartitionWall

3.Heat recovering cell
Fluidizing air of heat recovering cell is heatedthrough the bed and flowed out from the upsideof partition wall to freeboard as secondary
combustion air.

Fluidized bed© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

4Fluidized bed and furnace
4.Double partition wall
Double partition walls are provided to prevent not
only combustion in heat recovering cells but also
influx of corrosive gas from combustion cell.

5.Fluidizing air nozzle
Fluidizing air nozzles are arranged uniformly anddesigned for 50-100% of boiler load.

6.Embedded heat exchanger
Approx. 35-45% of boiler heat recovery isabsorbed by embedded heat exchanger (finalsuperheater and embedded evaporator) which canbe sized in small heating surface due to high heattransfer rate in fluidized bed.
7.Fuel chute
Fuel is supplied in combustion cell only, and isburned in the combustion cell with low temperature
under poor air, and burned out completely in thefreeboard with high temperature under rich air.

© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

Fuel Supply

Freeboard

DoublePartition
WallFluidized bed5

Fluidized bed and furnace
8.Refractory wall
Water walls of fluidized bed and freeboard on thebed are covered with refractory to keep suitablecombustion atmosphere.

9.Operating condition
Relation of operating condition among combustion
cell, heatrecovering cells, and BM circulation
cells, that is, bed temperature and fluidized air
velocity for each cell, is important.

Fuel Supply

Freeboard

DoublePartition
Wall

10.Water circulation
Large size downcomer is arranged for achieving
suitable natural circulation of boiler water.
Forced circulation system of boiler water is applied
to embedded evaporator and double partition wallswith high heat transfer rate to keep suitable watercirculation performance.

Fluidized bed© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

6Fuel Application

Fuel application

BFB

Internal Circulation
Fluidized BedBoiler

CFB

Wood Chip mono-firing

◎

◎

▲

Wood Chip + RDF or RPF

○

◎

▲

RPF or RPF mono-firing▲◎▲

Coal + Wood Chip○◎◎

Coal + RDF or RPF▲◎◎

Coal mono-firing▲◎◎

Wood Chip + Paper Sludge◎◎▲◎ Good 〇 Average ▲ Poor
© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

7Feature ofInternal Circulation Fluidized Bed Boiler
1. High combustion efficiency●Stable ignition & combustion by Dense bed⇒Low heating value fuel, High moisture fuel can be applied.
●Constant combustion temperature by BM circulating●Low NOx combustion by multi air feeding and low air-ratio
Combustion cell air⇒ Primary air

Circulation & Heat recovery cell air⇒ Secondary air

Freeboard air⇒ Tertiary air●High efficiency combustion by sufficient retention time in the furnace© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved8

Feature ofInternal Circulation Fluidized Bed Boiler
2. Low level erosion / corrosion●Separation of combustion zone and heat absorption zone bydouble partition wall
- Fuel can be completely fed into combustion celI
- Mild atmosphere of heat recovery cell
⇒ Arrangement of final SH is applicable!
●Low fluidizing velocity of heat recovery cell（0.5～0.6m/s）⇒Prevention of erosion of embedded tube
●Heat transfer coefficient is very large (more than 5 times ofconvection heating area)⇒ Compact design of embedded tube

© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved9

Feature ofInternal Circulation Fluidized Bed Boiler4. Easy Operation & Easy Maintenance●Bed temperature control ⇒ Stable evaporation・Heat absorption can be controlled by air flow of circulating cell・Heat absorption of embedded tube can be controlled by operating
temperature of heat recovery cell
●Limited maintenance area
・Main maintenance area is “Bed area” and “Material handlingsystem” only
・Low fouling of convection heating area
・Low erosion of furnace upper area and convection tube

© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved10

Feature ofInternal Circulation Fluidized Bed Boiler
3. High Reliability●Low erosion of upper furnace and convection heating area
・No eruption of BM(Bed Material)⇒No need of countermeasure of erosion for furnace upper part・Low dust concentration at convection heating area
⇒Low risk of erosion of convection heating tube
●Simple circulating system of Bed Material
・Circulating area of BM is the bottom of furnace only
・No cyclone ⇒ No maintenance of cyclone refractory© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

11Omuta Recycle Power

Pellet type RDF© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

Boiler TypeInternal Circulation
Fluidized Bed Boiler

Evaporation

91 t/hSteam Press.
Steam Temp.

8.14MPa×503 ℃

FuelRDF

FuelConsumption

RDF：315 t/dEmission

NOx：65ppm
SOx： 3.0m3N/h
HCｌ： 32.5mg/m3N
Dust：20mg/m3N
DXN：0.1ngTEQ/m3N
CO：100ppm(O2=12%,dry)Plant site

Fukuoka prefecture

Delivery year

2003
12

Tokushu Tokai Paper/Shimada
Boiler typeInternal Circulation
Fluidized Bed Boiler

Evaporation

75 t/hSteam Press.
Steam Temp.

9.81MPa×501 ℃

Fuel

Waste wood chip, RPF
Waste plastic

FuelConsumption

Waste Wood Chip
© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

Wood chip：9.0t/h
Waste Plastic：2.2t/h
RPF：0.8t/h

EmissionNOx：50ppm(O2=6%,dry)
SOx： 10ppm（O2=12%,dry）
HCｌ： 100ppm
Dust：0.04g/m3N
DXN：0.1ngTEQ/m3N
CO：100ppm

Delivery year

2006
13

Korea／Iksan city Commerce & Industry Energy Co., Ltd.

RDF (Soft Type)© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved

Boiler typeInternal Circulation
Fluidized Bed Boiler

Evaporation

75 t/hSteam Press.
Steam Temp.

6.37MPa×450 ℃

Fuel

RDF、Coal

FuelConsumption

RDF：210 T/D
Coal：65.5 T/D（RDF&Coal co-firing）

EmissionNOx：70ppm
SOx： 30ppm
HCｌ： 20ppm
Dust：0.02g/m3N
DXN：0.1ngTEQ/m3N
CO ：50ppm（O2=12%,dry）

Delivery year

201214© 2013 Kawasaki Heavy Industries, Ltd. All Rights Reserved15