Ash Reinjection

8/12/2019 Ash Reinjection

1/22

KEPRIKEPRI

03 APEC03 APEC--Clean Fossil Energy Technical & Policy SeminarClean Fossil Energy Technical & Policy Seminar

CCT Experience of TongCCT Experience of Tong--Hae CFB BoilerHae CFB Boiler

Using Korean AnthraciteUsing Korean Anthracite

Combustion & Thermal Engineering Group,Combustion & Thermal Engineering Group,

Power Generation Laboratory, KEPRI, KEPCOPower Generation Laboratory, KEPRI, KEPCO

J. M. LeeJ. M. Lee, J. S. Kim, J. J. Kim, J. S. Kim, J. J. Kim


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KEPRIKEPRI


IntroductionIntroduction

Elec

tricPower[

MW]

0

5000

10000

15000

20000

25000

30000 Nuclear

Coal-fired

LNG-fired

Oil-fired

Hydro

1999 2000 2005 2010 2015

Year Year

'99 '00 '01 '02 '03 '04 '05 '06 '07 '08 '09

Coal

Consump

tion

[thousan

dton

]

0

10000

20000

30000

40000

50000

60000

bituminous coal

anthracite coal

Need to activate a domestic coal industry

Electric Power Generation with Energy SourceElectric Power Generation with Energy Source Consumption of Imported and Domestic CoalConsumption of Imported and Domestic Coal

Tonghae Circulating Fluidized Bed Boiler

- Electric Power Generation : 1, 2 units 200 MWe (693 Steam t/h)

- Using Korean Anthracite

- The First and Largest CFB boiler using Low Quality Coal


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KEPRIKEPRI


Plan of the Tonghae Thermal Power Plant CFBPlan of the Tonghae Thermal Power Plant CFB

Unit #Unit # #1 Unit#1 Unit #2 Unit#2 Unit

Start EngineeringStart Engineering 1994. 121994. 12 1994. 121994. 12

Start Site ExcavationStart Site Excavation 1995. 21995. 2 1996. 41996. 4

Start Steam GeneratorStart Steam Generator

1995. 101995. 10

1996. 121996. 12

Steel ErectionSteel Erection

Initial FiringInitial Firing 1997. 101997. 10 1999. 31999. 3

SynchronizationSynchronization 1998. 11998. 1 1999. 71999. 7

Commercial OperationCommercial Operation 1998. 101998. 10 1999. 101999. 10

Participants in the Tonghae CFB ProjectParticipants in the Tonghae CFB Project

KEPCOKEPCO :: End UserEnd User -- (Korea East(Korea East--West Power Co.)West Power Co.)

KOPECKOPEC :: Project Architectural DesignProject Architectural Design

ABBABB--CECE :: Basic DesignBasic Design

DOOSANDOOSAN :: Boiler Equipment Fabrication and ProcurementBoiler Equipment Fabrication and Procurement


4/22KEPRIKEPRI


Commercial CFB Boiler Location in KoreaCommercial CFB Boiler Location in Korea

Company (Location) CategoryCapacity

(MW)

Steam

(T/H) Fuel Start Supplier

Oriental Chemical

(Inchon)Chemical 12.5 120 Bitu. Coal, Pet. Coke 1985 Hyundai /Ahlstrom

Sunkyung (Suwon) Textile - 130 Bitu. Coal 1988

Sunkyung (Ulsan) Textile 27 200 Bitu. Coal, Pet. Coke 1989

Hyundai Oil (Susan) Refinery - 120 Pet. Coke 1989

LGChemical (Yochon) Chemicals 25 210 Bitu. Coal 1989

Petrochemical Service Co(Ulsan)

Cogen. - 250 Bitu. Coal, Pet. Coke 1990

Sunil Glucose (Inchon) Food 9.2 60 Bitu. Coal, Heavy Oil 1991

Dyeing Complex (Taegu) Dye 54.1 130 x 3 Bitu. Coal 1986 Samsung/Babcock

Jeil Sugar (Seoul ) Food 5.4 40 Bitu. Coal 1988

Hansol Paper (Jeunju ) Paper 23 130 Bitu. Coal 1990

Dyeing Complex (Pusan) Dye - 80 Bitu. Coal, Heavy Oil 1991 Daewoo/B&W

Korea Energy (Ulsan) Metal 43.5 175 Bitu. Coal 1991 Hanjung/Lurgi

KEPCO(Tonghae #1, #2) Electricity 200x2 693 Anthracite 1998 Hanjung/ABB-CE

TonghaeTonghae

CFB BoilerCFB Boiler

200X2 MWe200X2 MWe

UlsanUlsan

SusanSusan

InchonInchonSuwonSuwon

TaeguTaegu

YochonYochon

JeunjuJeunju

CFB Boiler in KoreaCFB Boiler in Korea

By Lee

PusanPusan


5/22KEPRIKEPRI


Complete View of the Tonghae Power PlantComplete View of the Tonghae Power Plant

Main Office CFB Power Block

Ash Pond Indoor Coal Yard

03 A C03 APEC


6/22KEPRIKEPRI


Power Generation Process of the Tonghae CFBPower Generation Process of the Tonghae CFB

03 APEC03 APEC Cl il h i l & li S iCl F il E T h i l & P li S i


7/22KEPRIKEPRI


Tonghae CFB boilerTonghae CFB boiler TypeType-- CFB, IndoorCFB, Indoor

-- Natural CirculationNatural Circulation-- Balanced Draft SystemBalanced Draft System

Leading SpecificationLeading Specification

-- Steam Flow : 693 T/HSteam Flow : 693 T/H

-- Max. Operating P @ T:Max. Operating P @ T:169.6 kg/cm169.6 kg/cm22, 541, 541ooCC

Emission Control DesignedEmission Control Designed

-- SOSO22 (O(O22:6%) : 180ppm /:6%) : 180ppm /150ppm150ppm

-- NOx(ONOx(O22: 6%) : 250ppm /: 6%) : 250ppm /350ppm350ppm Ash DistributionAsh Distribution

-- Fly Ash : 50%Fly Ash : 50%

-- Bottom Ash : 50%Bottom Ash : 50%

Rectangular Furnace DesignRectangular Furnace Design-- More than 2:1 Aspect RatioMore than 2:1 Aspect Ratio

: to Allow for Good Fuel Mixing: to Allow for Good Fuel Mixing

-- Size : 32m (H) x 19m (W) x 7m (L)Size : 32m (H) x 19m (W) x 7m (L)

-- StartStart--up Burner (Side Wall) : 4up Burner (Side Wall) : 4-- Lance Burner : SideLance Burner : Side--2, Rear2, Rear--33

03 APEC03 APEC Cl F il E T h i l & P li S iCl F il E T h i l & P li S i


8/22KEPRIKEPRI


TT--Style Fluidizing NozzleStyle Fluidizing Nozzle

: ABB: ABB--CE PatentedCE Patented

: Minimize Potential Nozzle Plugging: Minimize Potential Nozzle Plugging

Large Opening : Minimize Pressure DropLarge Opening : Minimize Pressure Drop To Preclude BacksiftingTo Preclude Backsifting

Cyclones and SealpotsCyclones and Sealpots

3 Layer Refractory Lined3 Layer Refractory Lined

-- Insulating,Insulating,

Firebrick,Firebrick,

Erosion Resistant Brick layerErosion Resistant Brick layer

ProvidedProvided Vortex FinderVortex Finder

Loop seal (Sealpots)Loop seal (Sealpots)

-- to Prevent Material Backto Prevent Material Back--upup

Fluidizing NozzleFluidizing Nozzle


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03 APEC03 APEC Clean Fossil Energy Technical & Policy SeminarClean Fossil Energy Technical & Policy Seminar


10/22KEPRIKEPRI


Convective BackpassConvective Backpass

Steam cooledSteam cooled backpass wallbackpass wall and convectiveand convective backpass tubesbackpass tubes DesuperheaterDesuperheater stations, and retractablestations, and retractable soot blowerssoot blowers

Air HeaterAir Heater

AirAir -- GasGas -- Over Tubular TypeOver Tubular Type

Three Major Section :Three Major Section :

: Primary Air (: Primary Air (PAPA) and Secondary Air () and Secondary Air (SASA)) -- FurnaceFurnace

: Fluidizing Air (: Fluidizing Air (FAFA)) -- to FBHE, FBAC, Sealpotsto FBHE, FBAC, Sealpots

Fuel Feed SystemFuel Feed System

66--Fuel feed system (Fuel feed system (950~1000 kcal/m950~1000 kcal/m22

ss),), 33--Coal silo (16 hour capacity)Coal silo (16 hour capacity) GravimetricGravimetric feeders (10 : 1 Turn down ratio)feeders (10 : 1 Turn down ratio)

Lime Feed SystemLime Feed System

22--Limestone blower,Limestone blower, 22--Limestone silo (12 hour capacity)Limestone silo (12 hour capacity)

03 APEC03 APEC-Clean Fossil Energy Technical & Policy SeminarClean Fossil Energy Technical & Policy Seminar


11/22KEPRIKEPRI


Circulating Fluidized Bed CombustionCirculating Fluidized Bed Combustion

Solid FluidizationSolid Fluidization-- Lower part of furnace : dense phaseLower part of furnace : dense phase-- Upper part of furnace : dilute phaseUpper part of furnace : dilute phase

-- Annulus and core structureAnnulus and core structure-- Furnace Cyclone LoopsealFurnace Cyclone Loopseal

(FBHE) Furnace(FBHE) Furnace

Emission ControlEmission Control-- DesulfurizationDesulfurization in combustorin combustor:: CaCOCaCO33(fed) + SO(fed) + SO22 + 1/2O+ 1/2O22

CaSOCaSO44 + CO+ CO22-- Low operation temperature (


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KEPRIKEPRI


Analysis of Korean AnthraciteAnalysis of Korean Anthracite

Dogae Dongwon Samchuk Kyungdong Jangsung Hanbo TaebakProximate analysis

Moisture 3.26 3.07 3.60 3.76 2.82 4.46 4.15

VM 3.90 4.33 3.89 3.92 5.00 4.09 3.68

FC 60.86 51.00 58.44 65.32 47.02 60.40 61.58

Ash 31.98 41.60 34.07 27.00 45.16 31.05 30.59

Ultimate analysis

C 63.21 52.58 60.76 68.79 49.41 63.74 64.38

H 0.77 0.77 0.82 0.82 0.80 0.79 0.80

O 2.16 3.01 2.41 2.41 2.48 2.10 2.16

N 0.39 0.36 0.43 0.43 0.40 0.46 0.50

S 0.41 0.36 0.24 0.24 0.44 0.41 0.22Ash 33.06 42.92 35.34 35.34 46.47 32.50 31.92

Ash analysis

SiO2 53.41 54.36 56.41 52.58 54.51 52.37 54.20

Al2O3 34.82 31.53 31.38 32.99 32.54 33.67 32.27

Fe2O3 2.60 4.40 2.53 6.10 4.17 5.60 4.39CaO 0.80 0.86 0.58 0.99 0.72 0.84 0.92

MgO 0.65 0.70 0.65 0.72 0.62 0.44 0.78

Na2O 0.16 0.33 0.34 0.20 0.23 0.14 0.24

K2O 4.65 4.93 4.08 3.71 4.77 4.0 4.13

TiO2 2.14 1.83 2.02 2.24 2.24 2.77 1.95HGI 93 93 105 73 - 82 -



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KEPRIKEPRI


Size Distribution of Korean AnthraciteSize Distribution of Korean Anthracite

Size (mm) Design PSD (wt.%) #1 PSD (wt.%) #2 PSD (wt.%) #3 PSD (wt.%)

> 9.5

5.6 9.5

4.75 5.6

2.8 4.75

2 2.8

1.0 2.0

0.6 1.00.25 0.6

0.1 0.25

0.075 0.1

< 0.075

0

0

1.0

2.0

16.0

31.0

16.017.0

10.0

2.0

5.0

1.0

14.4

5.1

12.3

7.2

20.0

14.614.6

5.8

3.0

2.0

0

5.0

1.2

2.9

2.4

14.0

20.026.0

17.9

3.1

11.0

0

24.4

5.1

11.5

4.0

11.0

6.012.0

13.6

2.4

10.0

Size Change of Korean AnthraciteSize Change of Korean Anthracite Effect of heating rate and particle size on fragmentation Devolatilization

&

Combustion



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KEPRIKEPRI


T e m p e r a t u re [o

C ]

dW/dT

- 0 . 1 2

- 0 . 1 0

- 0 . 0 8

- 0 . 0 6

- 0 . 0 4

- 0 . 0 2

0 . 0 0

0 . 0 2

0 . 0 4

0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0

NormalizedWeighLoss[-]

0 .0

0 .2

0 .4

0 .6

0 .8

1 .0

1/T [1/K]

0.0008 0.0009 0.0010 0.0011 0.0012 0.0013 0.0014

lnK

-10

-9

-8

-7

-6

-5

E = 14.5 [kcal/mol]

ko= 0.9518 [s-1

]

E = 1.5 [kcal/mol]

ko= 7.6937x10-4

[s-1

]

E 0 [kcal/mol]

ko= 2.6176x10

-4[s

-1]

gas film C.R

po re di ffusio n C .R

chemical reaction C.R

Shrinking Core Model FitVolumetric Model Fit

900 800 700 600 500

E = 16.5 [kcal/mol]

ko=11.2389 [s

-1]

chemical reaction C.RE = 2.3 [kcal/mol]ko= 4.7472x10

-3 [s

-1]

po re di ffusio n C .R

E 0 [kcal/mol]

ko= 8.3601x10-4

[s-1

]

gas film C.R

Combustion Characteristics of Korean AnthraciteCombustion Characteristics of Korean Anthracite

Temperature [o

C]

0 200 400 600 800 1000

W/W

o[-]

0.0

0.2

0.4

0.6

0.8

1.0

Tonghae CoalBituminous coal

1/T [K-1

]

0.0008 0.0009 0.0010 0.0011 0.0012

lnK

-9

-8

-7

-6

-5

-4

-3

E = 51.2 [kcal/mol]

ko= 1.492x1010 [s -1]

900 800 700 600 550

E = 23.5 [kcal/mol]

ko= 1.695x10

3 [s

-1]

E = 0.5 [kcal/mol]

ko= 0.024 [s-1

]

gas film

control regime

pore dif fusion

control regime

chemical reaction

control regime

3/210 )1()25767exp(10492.1 2 XPTdtdX O =

Ignition T : 500Ignition T : 500 -- 600600ooCC

-- very low combustion reactivityvery low combustion reactivity

Chemical reaction control regime :Chemical reaction control regime :

33--10 times lower than bituminous10 times lower than bituminous

T e m p e r a t u r e [oC ]

0 1 0 0 2 0 0 3 0 0 4 0 0 5 0 0 6 0 0 7 0 0 8 0 0 9 0 0 1 0 0 0

NormalizedWeightLoss[-]

0 .2

0 .4

0 .6

0 .8

1 .0

dW/dT

-0 .12

-0 .10

-0 .08

-0 .06

-0 .04

-0 .02

0 . 0 0

0 . 0 2

0 . 0 4



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KEPRIKEPRI

03 APECClean ossil ne gy echnical & olicy Seminagy y

Low Volatile contentLow Volatile content-- VM : 3.7VM : 3.7--5.0%5.0%

High Ash contentHigh Ash content

-- Ash : 27Ash : 27 -- 42%42%

Low heating valueLow heating value-- 4,5004,500--5,000 kcal/kg5,000 kcal/kg

Relatively high HGIRelatively high HGI

-- about 90about 90 -- 110110

Korean anthraciteKorean anthracite

VeryVery low combustion reactivitylow combustion reactivity

High content of fine particlesHigh content of fine particles (


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KEPRIKEPRI

gy ygy y

Initial Experience of the Tonghae CFB BoilerInitial Experience of the Tonghae CFB Boiler

High temperatureHigh temperature andand Longer timeLonger time during bed material heat upduring bed material heat up

: in sealpots, cyclone inlet and outlet (1000: in sealpots, cyclone inlet and outlet (1000--11001100 ooC)C)

: in combustor (880~920: in combustor (880~920 ooC)C)

Formation ofFormation ofclinkers, Fouling of fine particlesclinkers, Fouling of fine particles

Low circulation rateLow circulation rate (upper(upper PP 100mmH100mmH22OOdesign : 170~190mmHdesign : 170~190mmH

22O )O )

:: higherhigher temperaturetemperature and unstable bed conditionand unstable bed condition (( 900900ooCC))

:: higherhigher SOx emissionSOx emission (Ca/S mole ratio(Ca/S mole ratio 3.03.0--3.5 (


17/22

KEPRIKEPRI

gy y

oo High temperature, Clinker formation in Sealpots and CyclonesHigh temperature, Clinker formation in Sealpots and Cyclones Grease (aeration) air line at sealpot (Grease (aeration) air line at sealpot (35 places at each sealpot35 places at each sealpot))

Grease air line around ACV at sealpot (Grease air line around ACV at sealpot (10 places at each ACV10 places at each ACV))

Observation windows at sealpot (Observation windows at sealpot (1 window at each sealpot1 window at each sealpot))

Duct water spray nozzle at cyclone inlet (Duct water spray nozzle at cyclone inlet (1 spray nozzle at each cyclone1 spray nozzle at each cyclone))o High temperature in combustor, Longer time during heat up bed maHigh temperature in combustor, Longer time during heat up bed materialterial

Injection port of bed media (Injection port of bed media (3 places furnace3 places furnace))

Lance burner in a furnace (Lance burner in a furnace (5 places5 places -- dense bed region in furnacedense bed region in furnace))

o Low circulation rateLow circulation rate Cyclone modification (Cyclone modification (Vortex finder, inlet duct width changeVortex finder, inlet duct width change))

o Defluidization and Clinker formationDefluidization and Clinker formation

Fluidizing nozzle modification (Fluidizing nozzle modification (Nozzle orifice angle and shape changeNozzle orifice angle and shape change))

Solid drain line (Solid drain line (7 places at fluidizing air line7 places at fluidizing air line)) Solid drain line at FBAC (Solid drain line at FBAC (Hot and cold region, respectivelyHot and cold region, respectively))

Bed media management system (Bed media management system (FBHE media drain and sieve systemFBHE media drain and sieve system))

o Low combustion efficiencyLow combustion efficiency

Ash reinjection system (Ash reinjection system (fromfrom A/H & EP hopper to combustorA/H & EP hopper to combustor))

Modification of the System of the Tonghae CFB boilerModification of the System of the Tonghae CFB boiler



18/22

KEPRIKEPRI

Example of System Modification (Ash reinjection system)Example of System Modification (Ash reinjection system)

Ash Hopper for Reinjection Reinjection Port of Combustor



19/22

KEPRIKEPRI

Current Status of the Tonghae CFB boilerCurrent Status of the Tonghae CFB boiler

Temperature [oC]

700 750 800 850 900 950 1000 1050

CombustorH

eight[m]

0

5

10

15

20

25

30

Cyclone inlet T

annuluscore

be fore modification

after modification Bed TemperatureBed Temperature

Design : < 900Design : < 900ooCC

BeforeBefore :: 900900ooCC

AfterAfter : 850: 850 -- 870870oo

CC Cyclone inlet TemperatureCyclone inlet Temperature

Design : 900Design : 900ooCC

BeforeBefore : 960: 960 -- 10201020ooCC

After : 910After : 910 -- 930930ooCC

Cyclone outlet TemperatureCyclone outlet TemperatureDesign : 927Design : 927ooCC

Before : 980Before : 980 -- 10201020ooCC

After : 940After : 940 -- 960960ooCC

Sealpot TemperatureSealpot Temperature

Before : 960Before : 960 -- 10001000ooCCAfterAfter : 900: 900 -- 930930ooCC

Bed Temperature DifferenceBed Temperature Difference

Somewhat decreaseSomewhat decrease

before ash reinjection after ash reinjection



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KEPRIKEPRIKEPRI

Gas Concentration [ppm]

0 10000 20000

Gas Concentration [%]

0 5 10 15 20

CombustorH

eight[m]

0

5

10

15

20

25

30

CO2

O2

H2O

0 500 1000

SO2

NOx

Sampling from Stack

CO

before modification

after modification


SOSO22 emissionemission

: decrease: decrease Ca/S mole ratioCa/S mole ratio

(150ppm) :(150ppm) :

Before :Before : 3.53.5

After : 2.5After : 2.5--3.03.0

Current Emission LevelCurrent Emission Level

-- SOSO22 (150) :(150) : < 110 ppm< 110 ppm

-- NOx (350) : < 50 ppmNOx (350) : < 50 ppm

-- Dust (50) :


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KEPRIKEPRI


Power Generation (1, 2 units)Power Generation (1, 2 units)

-- Power Generation at 2002 : aboutPower Generation at 2002 : about 2,400,000MWh2,400,000MWh

-- Overall Efficiency for Power Generation :Overall Efficiency for Power Generation : 36.88 %36.88 %

* Other Power Plant using Korean Anthracite : 30~34%* Other Power Plant using Korean Anthracite : 30~34%

(Combustion Efficiency : >90%)(Combustion Efficiency : >90%)

-- Coal Consumption :Coal Consumption : 1,214,000 ton/year1,214,000 ton/year

: shows Good Performance for Economical and Environmental eff: shows Good Performance for Economical and Environmental efficiencyiciency

Future Work for OptimizationFuture Work for Optimization

-- Reduce UBC in Fly ashReduce UBC in Fly ash: Unburned Carbon in fly ash: Unburned Carbon in fly ash15~18%15~18% ((bottom ashbottom ash3%)3%)

-- Complete Perfect FluidizationComplete Perfect Fluidization

: Unstable Fluidization in FBAC: Unstable Fluidization in FBAC



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KEPRIKEPRI

ConclusionsConclusions

Current StatusCurrent Status of the Tonghae CFB boilerof the Tonghae CFB boiler Good Performance and Efficiency for Combustion of Korean Anthracite

Good Environmental Efficiency (Gas emission and Ash utilization )

Stable Operation and Power Generation

ModificationModification of the system andof the system and OptimizationOptimization of the operationof the operation

Cyclone Modification Addition of Ash Reinjection System Nozzle Modification ..

Higher temperature in sealpots, cyclone inlet and outlet Lower circulation rate and unstable bed condition

Higher SOx emission (Ca/S mole ratio 3.0-3.5 (

Documents

Ash Reinjection