1

Recent Researchon Dioxin (DXN) Emission

from Metal Industrial Facilities

Shigenobu OKAJIMA, Dr. Eng.

Research & Development Department Plant & Infrastructure Engineering Company

KAWASAKI HEAVY INDUSTRIES, LTD.

2

CONTENTS1. Status of Dioxin Emission from Metal

Industrial Facilities 2. Control Technologies of Dioxin Emission

in Metal Industrial Facilities 2.1. Electric Steelmaking Furnace2.2. Iron and Steel Sintering Process2.3. Zinc Recovery Facility2.4. Aluminum Alloy Manufacturing

3

1. Status of Dioxin Emissionfrom Metal Industrial Facilities

3

44

2,3,7,8-tetrachlorodibenzo-p-dioxin(2,3,7,8-TeCDD)

2,3,4,7,8-pentachlorodibenzofuran(2,3,4,7,8-PeCDF)

3,3,4,4-tetrachlorobiphenyl(3,3,4,4-TeCB)

C

O

H

Cl

The term dioxins in Japan refers to PCDDs, PCDFs, and co-planar PCBs

in the Law Concerning Special Measures against Dioxins on July 16, 1999.

55

Table. Environmental Quality Standarts of Dioxins in Japan(Jan. 15, 2000, Sept. 1, 2002)

Air

Water Drinking Water Ground Water

Soil

Sediment

: 0.6 pg-TEQ/m3

: 1 pg-TEQ/L: 1 pg-TEQ/L: 1 pg-TEQ/L

: 1,000 pg-TEQ/g: 250 pg-TEQ/g (Target Value)

: 150 pg-TEQ/g

6

ExistingNew

10.1Iron and Steel Sintering Process

1

1

0.5

5Aluminum Alloy Manufacturing

10Zinc Recovery Facility

5Electric Steelmaking Furnace

Table. Emission Standards of Dioxinsfor Metal Industrial Facilities in Japan

6

(ng-TEQ/m3)

(Jan. 15, 2000)

7

ExistingNew

10

10

10Aluminum Alloy Manufacturing

10Zinc Recovery Facility

7

(pg-TEQ/L)

(Jan. 15, 2000)

Table. Effluent Standards of Dioxinsfor Metal Industrial Facilities in Japan

8

32Iron and Steel Sintering Process

787

20

118

Aluminum Alloy Manufacturing

Zinc Recovery Facility

Electric Steelmaking Furnace

Table. Number of Table. Number of Metal Industrial Facilities Reported toLocal Governments under Emission Standards

of Dioxins in Japan (March 31, 2003)

Local Governments under Emission Standardsof Dioxins in Japan (March 31, 2003)

8

9

87

14

Aluminum Alloy Manufacturing

Zinc Recovery Facility

9

Table. Number of Metal Industrial Facilities Reported toLocal Governments under Effluent Standards

of Dioxins in Japan (March 31, 2003)

10

203.8

14.7

19.6

9.2

65.0

95.3

2001

190.4

13.6

16.2

14.7

51.1

94.8

2002

178.3

13.6

13.2

8.3

50.8

92.4

2003

264.1

15.0

11.8

13.8

93.2

130.3

ReductionTarget

300.9

13.3

23.0

21.8

101.3

141.5

1999

263.8

14.2

22.2

26.5

69.8

131.1

2000

328.8

20.9

28.8

25.4

113.8

139.9

1998

30.7Aluminum Alloy Manufacturing

21.8Other Industrial Processes

1997

135.0Iron and Steel Sintering Process

463.4

47.4

228.5

Total

Zinc Recovery Facility

Electric Steelmaking Furnace

Table. Trend of the Annual Dioxin Emissionfrom Metal Industrial Facilities in Japan

10

(g-TEQ/y)

Estimated

11

1.99

0.0817

0.0036

2001

0.99

0.0243

0.0026

2002

0.98

0.0243

0.0026

2003

-

-

-

ReductionTarget

5.77

0.0925

0.0036

1999

4.80

0.0555

0.0036

2000

5.67

0.0675

0.0036

1998

0.340Aluminum Alloy Manufacturing

1997

6.14

0.0036

Total Industrial Facilities

Zinc Recovery Facility

Table. Trend of the Annual Dioxin Effluent from Metal Industrial Facilities in Japan

11

(g-TEQ/y)

Estimated

12

0.111157.40 - 0.1131010Zinc Primary Smelling Facilities

0.0884,403,000111Copper Recovery Facilities

0.005

0.22

14.7(0.0026)

51.1

90.6(4.3)

Annual Emission (g-TEQ/y)

0.012 - 0.31

0.01418 - 0.47018

0.00053 - 18.4(0.01 - 1.4)

0.013 - 0.68

0 - 9.7(0.00015 - 0.67)

DXN Conc.

(ng-TEQ/m3[N])

960.7

2,436.1

48,019.2(14.7)

480.6

3,062.2

Emission Factor

(ng-TEQ/t)

4

3

20(4)

34

104(22)

Number of Data(-)

3Lead Recovery Facilities

4Precious Metals Recovery Facilities

Number of Facilities

(-)

26Iron and Steel Sintering Process

16(3)

95(30)

Zinc Recovery Facility(To Water)

Electric Steelmaking Furnace(From Building Atmosphere)

Table. Estimated Annual Dioxin Emissionfrom Metal Industrial Facilities in Japan (2002) (#1/3)

12

Effluent (pg-TEQ/L)

13

[Breakdown]

0.20.023 - 3.82524Aluminum Scrap Melting ProcessOwned by Distributors of Scraps

of Cars and Metals

13.8Melting Furnace for Melting Process

0.07Melting Furnace for Purification Process

0.014

1.6

0.22

0.39

14.4

Annual Emission (g-TEQ/y)

0.000017 - 0.18

0 - 0.5

0 - 6.3

DXN Conc.

(ng-TEQ/m3[N])

716.4

Emission Factor

(ng-TEQ/t)

6

95

192

Number of Data(-)

145Aluminum Scrap Melting Process

in Aluminum Rolling

6Aluminum Scrap Melting Process

in Aluminum Casting and Die-casting

Number of Facilities

(-)

Drying Furnace

244

Roaster

Aluminum Alloy Manufacturing

Table. Estimated Annual Dioxin Emissionfrom Metal Industrial Facilities in Japan (2002) (#2/3)

13

14

0.13490.00.000047 - 1.23437Car Component Manufacturing (Aluminum Casting

and Die-casting)

(0.024)(13.0)(0.00014 - 5.8)(24)(17)Aluminum Alloy Manufacturing (Aluminum Rolling etc.)

(To Water)

(0.0003)

1.97

0.2040.049

0.02

Annual Emission (g-TEQ/y)

(0.0014 - 0.2)

0 - 3.6

0 - 0.92

0.0000066 - 0.7

DXN Conc.

(ng-TEQ/m3[N])

3,533.2

203.2306.6

Emission Factor

(ng-TEQ/t)

(7)

48

16

13

Number of Data(-)

(7)Aluminum Alloy Manufacturing (Car and Car

Component Manufacturing)(To Water)

Number of Facilities

(-)

16Aluminum Casting and Die-casting Manufacturing

Reverberating FurnaceMelting Pot or Crucible

46

13

Car Manufacturing (Aluminum Casting and Die-casting)

Drying Process of Aluminum Cutting Waste inCar and Car Component Manufacturing

Table. Estimated Annual Dioxin Emission from Metal Industrial Facilities in Japan (2002) (#3/3)

14

Effluent (pg-TEQ/L)

15

2. Control Technologies of Dioxin Emissionin Metal Industrial Facilities

15

1616

1717

1818

Fig. Formation Route of PCDDs/PCDFsin Combustion Processes Proposed by Takeuchi

(Tetsu-to-Hagan, Vol.89, p.812, 2003)

(1) CBz, CPh (Precursors) PCDDs/PCDFs(2) PAH PCDDs/PCDFs(3) Soot PCDDs/PCDFs

1919

Fig. A Scheme for Catalytic Mechanism of CuCl2 in Soot Oxidation Proposed by Mul (Tetsu-to-Hagan, Vol.89, p.817, 2003)

R1 : 4CuCl + O2 2Cu2OCl2R2 : Reduction of Cu2OCl2 by Carbon

Formation of Compounds Including Oxgen (C-Os) + CuClR3 : Elimination of C-Os CO/CO2R4 : CuCl-O CuO + 1/2Cl2R5 : CuCl2 2CuCl + Cl2

2020

0

100

200

300

400

500

600

Tem

p. (

)

non-

mon

o- di-

tri-

tetr

a-

pent

a-

hexa

-

hept

a-

octa

-

Fig. Melting Point and Boiling Point of PCDDs/PCDFs(Chemosphere, Vol.18, Nos.1-6, pp.783-788, 1989)

M.P. B.P.PCDDs: PCDFs:

400

300

150Solid Phase

Gas Phase

2121

A Summary of Prevention and the Destructionof DXN in Metal Industrial Facilities (#1/2)

Quality control of scrap or dust inputs depending on the process used. The use of the correct feed material for the particular furnace or process. Selection and sorting to prevent the addition of material that is contaminated with organic matter or precursors can reduce the potential for dioxin formation.The use of optimum combustion conditions. The use of oxygen injection in the upper part of a furnace to ensure complete combustion of furnace gases if necessary to achieve this.The use of correctly designed and operated afterburners and rapid quenching of the hot gases to < 250.

2222

A Summary of Prevention and the Destructionof DXN in Metal Industrial Facilities (#2/2)

Very high efficiency dust removal, for example high efficiency fabric filters or ceramic filters.Absorption onto activated carbon in a fixed bed or moving bed reactor or by injection into the gas stream, and removal as filter dust. The use of a catalytic oxidation stage or fabric filters that incorporate a catalytic coating.Treatment of collected dusts in high temperature furnaces to destroy dioxin and to recover metals.

23

2.1. Electric Steelmaking Furnace

23

2424

Present production of iron and steel is approximately 700 - 800 million tons in the world and 100 - 110 million tons in Japan.Production of sintered ore is approximately 100 million tons in Japan.The percentage of electric are furnace (EAF) steel of the overall steel production are approximately 30 % in Japan. Thirty million tons of crude iron and steel, therefore, are produced in EAFs.The direct smelting of iron-containing materials such as scrap is usually performed in EAFs which play an important and increasing role in modern steel works concepts.

Production and Recycling of Iron and Steel

2525

2626

2727

2828

2929

Fig. A Chart of Temperature, CO2, O2, and CO of Flue Gas in an EAF Plant

Time

CO

(ppm

)O

2 (%

)C

O2

(%)

Tem

pera

ture

()

Time

Time

Time

Termination of PD

Inlet of Dust CollectorOutlet of EAF

Inlet of Dust CollectorOutlet of EAF (1/100)

Completion of MeltingCompletion of 1st PD

Starting of Power Distribution (PD)

Inlet of Dust Collector

Outlet of EAF

Inlet of Dust Collector

Outlet of EAF

CO 150,000 ppm= 15 %

3030

Fig. Typical Dust Collection Systems in EAF Plants (Left: Separated Type; Light: Combined Type)

EAFCombustion

Chamber

GasCooler

Dust Collector for the Evacuation of the Building Atmosphere

EAF CombustionChamber

GasCooler

Dust Collectorfor the EAF

3131

Fig. An Example of Scrap Preheating Equipment

EAF

CombustionChamber

Bucket

Fan

RotaryLid

GasCooler

Body of PreheatingEquipment

DustCollector

RegulationValue

3232

921719233PCDDs/PCDFs at the Stack

-708-35-2,308-447Filtration and Dilution Effects in theDust Collector

-15,800-278--Dilution Effect in Combined Flue Gaswith the Building Atmosphere

14,800---de novo Synthesis in Scrap Preheating-2712,390426de novo Synthesis from 500 to 300

2,2005911054Formation of PCDDs/PCDFs in the EAF

D PlantC PlantB PlantA Plant(ng/m3[N])

Table. Changes of PCDDs/PCDFs in EAF Plants

3333

Replaced by a Quenching Tower for Rapid Cooling of the Off Gas

3434

3535

DXN

(ng-

TEQ

/m3 [N

])

Fig. Scatter Plot of Temperature of the Inlet of Dust Collectorsand DXN Conc. in Flue Gases

Temperature ()

Separated TypeCombined Type

3636

3737

Fig. Injection System of Activated Carbon Powderfor Off Gas Treatment

For the EAF MixingTower

Dumper

For the Building Atmosphere

Blower

Blower

CombustionChamber

GasCooler

Dumper ActivatedCarbon Powder

Injection Unit

Dust Collectorfor the EAF

Dust Collector forthe Evacuation of theBuilding Atmosphere

3838

Fig. Dioxin Control in Thermal Processes fromResults of MSW Incineration Studies

3939

DXN

(ng/

g)Solid Phase

Fig. de novo Synthesis in EAF Dust Heated at the Temperatures of 100, 150, and 200

Non-treatedEAF Dust

Gas Phase

Memory Effect in Dioxin Formation

40

2.2. Iron and Steel Sintering Process

40

4141

4242

4343

Ignition Furnace Air

Cooling Zone

Wet Zone

Incineration or Melting Zone

Moving Direction of Sintering Bed

Drying or Calcinations ZoneWindow Boxes

Fig. Schematic Sintering Process

4444

CrossSection

4545

(Tetsu-to-Hagan, Vol.87, p.230, 2001)

4646

(Tetsu-to-Hagan, Vol.87, pp.230-231, 2001)

4747

(Tetsu-to-Hagan, Vol.87, p.232, 2001)

4848

(Tetsu-to-Hagan, Vol.87, p.230,p.232, 2001)

4949

SinteringEquipment

Flue Gas

(Tetsu-to-Hagan, Vol.87, p.232, 2001)

Sintered Ore(Product)

Dust from Off Gas Dedusting (ex. D-EP Dust)

Recycled Sinter

Other RecycledMaterials

NewMaterials

5050

5151

Table. Experimental Conditions and Results for Sinter-pot Tests

1.74000.423.0 + 5.0 + 1.0 +

3.0

Anth. + Mill Scalte + EP Dust +BF Dust1.6C 8

1.62504.25.0 + 1.0Mill Scale + EP Dust1.6C 7

0.201701.23.0 + 5.0Anth. + Mill Scale1.6C 6

1.33701.53.0 + 1.0Anth. + EP Dust1.6C 5

0.090903.73.0BF Dust1.6C 4

1.6844.51.0EP Dust (Sintering)1.6C 3

0.10554.25.0Mill Scale1.6C 2

0.083621.53.0Anthracite1.6C 1

0.16C BASE

2.55804.00.08 + 0.05NaCl + Oil1.3B 4

0.11904.00.05Oil for Rolling1.3B 3

2.55804.00.08NaCl1.3B 2

2.45804.00.09PVC1.3B 1

0.05B BASE

2.410504.40.17 + 0.10NaCl + OilVariableA 4

0.04504.50.10Oil for RollingVariableA 3

0.6510504.50.17NaClVariableA 2

6.010504.50.18PVCVariableA 1

0.03A BASE

Amount of

DXN(g/kg-mixture)

T.Cl Contentin Mix.

(mg/kg)

Coke Added(mass%)

Mixing Ratio(mass%)

AdditivesGas Flow Rate(m3[N]/min)

No.

(Tetsu-to-Hagan, Vol.87, p.234, 2001)

5252

(Tetsu-to-Hagan, Vol.88, p.373, p.375, 2002)

5353(Tetsu-to-Hagan, Vol.88, p.384, 2002)

5454

5555

5656

5757

5858

59

2.3. Zinc Recovery Facility

59

6060

Table. Production and Consumption of Zinc in Japan

300,000 - 350,000Amount of EAF Dust

700,000 - 750,000

(250,000 - 350,000)

Amount of Domestic Consumption

(Of Which Amount for Zinc Galvanized Sheet Iron)

60,000Amount of Zinc Recovery from EAF Dust

20,000 - 50,000Amount of Export

100,000 - 150,000Amount of Import

600,000 - 650,000Amount of Domestic Production

(t/y)

The amount of zinc reovery from EAF dust is approximately tenth part of that of domestic production.

6161

Fig. A Summarized Flow Sheet of Five Major ZincRecovery Facilities in Japan

Volatiling Furnace(Rotary Kiln)

Sintering Furnace(Dwight Lloyd Type)

Distilling Furnace(Electrothermic Furnace )

EAF Dust, etc

Reducing Furnace(MF Furnace, Rotary Kiln) Drying and Heating

Furnace

Refining (Anode)Furnace

(Rotary Kiln)

Electric Arc Furnace

6262

6363

Fig. A Schematic Layout of MF Furnace

ShutteConveyor

BypassFlue

Boiler

CokingZone

Settlor

MeltingZone

CokeEAF DustLimestone

Air

CoolingWater

Slag, Metal

Crude ZuOCyclones

Crude ZuO

Crude ZuO

FanStackBF

Gas CoolerFurnace

Off Gas

6464

Fig. A Schematic Layout of Electrothermic Furnace

Table forDischarge

LowerElectrode

UpperElectrode

Opening forInput

Materials

RotaryChute

CycloneAir Supply for

Oxidation

BF

DischargeOpening

6565

6666

Table. Examples of Composition of EAF Dust

0.114.20.803.703.131.12.1021.9

0.206.81.002.901.420.12.8832.3

0.254.91.603.703.624.71.9021.5

0.134.60.503.101.530.92.7029.4

0.490.30.743.0018.924.70.2019.2

0.013.28.6013.406.752.72.8020.3

0.093.32.401.500.516.01.6015.9

0.304.20.203.903.127.91.8020.7

0.401.90.803.904.534.90.9021.6

0.321.20.600.013.325.50.7025.8

0.154.21.403.505.127.52.6019.6

0.201.90.506.703.135.00.0216.0

0.464.81.504.602.034.20.4018.0

0.334.02.703.508.226.92.6022.7

0.032.23.203.804.435.91.3017.8

F %Cl %C %SiO2 %CaO %Fe %Pb %Zn %

DXN Conc. 0.22 43 ng-TEQ/g (ave. 3 ng-TEQ/g)

67

2.4. Aluminum Alloy Manufacturing

67

6868

Frame of Windows Casting

Turnings (Swarf)Can

DXN Conc. in Flue Gas of Aluminum Melting FurnacesUsed Beverage Can (UBC), Frame of WindowsTurnings, Swarf : High

: Low

6969

Table. Recycling and Final Disposal ofUsed Aluminum Cans in Japan (2002)

(9.1 %)

(20.6 %)

(70.3 %)

[Breakdown]

49,000 t/yFinal Disposal

50,000 t/yFor Die-casting and Casting

22,000 t/y

171,000 t/y

234,000 t/y

292,000 t/y

For Deoxdizing agents and Commodities

For Aluminum Alloys

Recycling

Consumption

14.72 billion cans

17.78 billion cans

Total Aluminum Consumption : 3,900,000 t/yTotal Aluminum Recycling : 1,450,000 t/y

7070

Fig. Scrap Pre-heating, De-coating, and Melting Processfor UBC (Used Beverage Can)

Cyclone

Airlock

Exhaust

Dust

Air

Fuel

Molten Aluminum

Fan for Hot Gas

AirFuel

Water

Fan

Airlock

AirlockRotary Kiln(> 500)

Scrap Discharge Opening

Water

Inlet forUBCScrap

ReverberatoryFurnace

Combustion Chamber (800)

7171

7272

BF

800

Charge ofTurnings (Swarf)

Flue Gas

Burner

Burner

300 - 500

Discharge ofTurnings (Swarf)

Cyclone

Coolingby Air

Fig. Drying Process for Turnings

Combustion Furnace

Rotary Kiln

7373

7474

Fig. Examples of Aluminum Melting Reverberatory Furnace(Upper: Side Well Type; Lower: Standard Type)

Scrap

Scrubber

Flue Gas fromthe Combustion

(Melting) Furnace

Refining Agents(Flux, Gases)

Burner

GasCooler

BF

Flue Gas

Combustion (Melting)Furnace

Stacking Machine

Stacking Machine

Casting

Product

Product

Flue Gas

Casting

HoldingFurnace

BFGasCooler

Flue Gas formthe Fore-furnace

Fore-Furnace

7575

(Organohalogen Compounds, Vol.56, p.214, 2002)

7676(Organohalogen Compounds, Vol.56, p.215, 2002)

7777

(Organohalogen Compounds, Vol.56, p.216, 2002)

7878

Table. Factors of DXN Formation in Secondary Aluminum Production

Recycle Oil(Chlorine Content0.001 0.22 %)

Fuels

9.16

Melting FurnaceMemory Effect

in the Off Gas Dust

Chlorine MixturesChloride (Salt Flux)

Aluminum Scrap

700 750 200 500

(Batch Process)

Melting Process

0.147

De-coating Furnace

UBC

300 500

Off Gas Combustion: 800

De-coating Process

16.6

Drying Furnace

Turnings, Swarf

300 500

Off Gas Combustion: 800

Drying Process

Pre-treatment

Process Chemicalsand Gases

DXN Formation

in Processes

Materials

0.174Emission Factor

(g-TEQ/t)

Temperature

Refining Process

7979

Issues in Metal Industrial DXN Sourcesin Comparison with MSW Incineration Facilities

(1) MSW incineration facilities have coped with adoption of high combustion temperature. The adoption of such a countermeasure, however, is difficult in industrial thermal processes because keeping of the quality and yield of produets is necessary.

(2) Government budgets have been injected into improvement of equipment in MSW incineration facilities, while enterprises have to pay for improvement of their equipment or facilities for reduction of DXN emission.

(3) Reduction of the amount of MSW is widely required in MSW management; in contrast it is difficult to reduce production in enterprises.

8080

Thank you for your kind attention.

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