Lessons Learned Related to Lessons Learned Related to Dioxin Formation in Cement Dioxin Formation in Cement

KilnsKilnsRobert Schreiber - Schreiber, Yonley & Associates

Manufacturing Technical Committee

PC MACT StandardPC MACT StandardDioxins & Furans Dioxins & Furans

Two part standard1. Dioxin standard - 0.2 ng/dscm TEQ

Temperature control - set during performance test

2. Dioxin standard - 0.4 ng/dscm TEQTemperature control - set during performance test

and less than 400oF

22

Dioxin MoleculeDioxin Molecule

33

Furan MoleculeFuran Molecule

44

Dioxin Versus TemperatureDioxin Versus Temperature

55

Preheater Precalciner Kiln

There are still five jobs to be done•Drying•Preheating•Calcining•Sintering•Cooling

60%Fuel Split

40%

66

Dry Process Preheater/Precalciner Dry Process Preheater/Precalciner SystemSystem

Temperature Profile PH/PC KilnTemperature Profile PH/PC Kiln

77

Wet Kiln Process Material and Gas TemperaturesWet Kiln Process Material and Wet Kiln Process Material and Gas TemperaturesGas Temperatures

88

Test Results Test Results -- Dioxin TEQsDioxin TEQs

99

Distribution of Organic Mass in Distribution of Organic Mass in Kiln EmissionsKiln Emissions

1010

Test Parameters for Historical Test Parameters for Historical StudyStudy

Test Run Kiln Conditions

1 - 3 Normal 4 - 6 Added Na2Co3 7 - 9 Added Na2Co3 + H2O

10 - 12 Added H2O 13 - 15 Coal Only

1111

Test Results Test Results Total Dioxin/Furans in Waste Dust Total Dioxin/Furans in Waste Dust and Stack Gasesand Stack Gases

1212

Test Results Test Results Comparison of Waste Dust Dioxin Comparison of Waste Dust Dioxin To Sodium in Waste DustTo Sodium in Waste Dust

1313

Test Parameters for Historical Test Parameters for Historical StudyStudy

Test Day Kiln Conditions 1 Normal

2 Addition of activated carbon (100 lb/hr) into duct work between kiln and ESP

3 Addition of atomized water (30 gal/min) into back end of kiln

4 Addition of atomized water (30 gal/min) into back end of kiln; set insufflation dust rate equal to zero

5 Addition to sulfur to raw mill (10 tons flake sulfur/4700 tons slurry

1414

Kiln Mass BalanceKiln Mass Balance

0.00

5000000.00

10000000.00

15000000.00

20000000.00

25000000.00

30000000.00

1 2 3 4 5

Tota

l (ng

/hr)

Test Day

Total in (ng/hr)

Dust- Total out (ng/hr)

Stack- Total out (ng/hr)

Total Dioxin

ND = 0

1515

Cement Kiln Dust Anomaly Cement Kiln Dust Anomaly During Test Day 2During Test Day 2

Test Day 2 Results:– Dioxin concentration on Test Day 2

averaged 34.61 ppt TEQ compared to 0.52 ppt for Test Day 1

– Dioxin concentration on Test Day 2 averaged 1341.7 ppt total D/F compared to 25.27 ppt for Test Day 1

The addition of activated carbon increased the dioxin concentration in the CKD by two orders of magnitude

1616

Statistical Analysis of High and Statistical Analysis of High and Low THC ITEQ DataLow THC ITEQ Data

-2 0 2 4 6 8

10 12 14

0 5 10 15 20 25 30ITEQ (ng/dscm)

Test Number

High and Low Total Hydrocarbon (THC) ITEQ Data

Series1

The prudent selection of raw materials has resulted in a dramatic decrease in dioxin emissions

1717

Statistical Analysis of High THC Statistical Analysis of High THC ITEQ DataITEQ Data

High Total Hydrocarbon (THC) ITEQ Data

-5

0

5

10

15

0 1 2 3 4 5 6 7 8

Test Number

ITEQ

(dg/

dcsm

) Series1

1818

Statistical Analysis of Low THC Statistical Analysis of Low THC ITEQ DataITEQ Data

Low Total Hydrocarbon (THC) ITEQ Data

-0.4-0.2

00.20.40.60.8

11.21.4

0 5 10 15 20

Test Number

ITEQ

(ng/

dscm

) Series1

1919

Dioxin Considerations in Dioxin Considerations in Cement KilnsCement Kilns

Temperature effectsRaw material effects on dioxin concentrationAlkali and chlorine effects

2020

Dioxin Considerations in Dioxin Considerations in Cement KilnsCement Kilns

Temperature effects: 450oF-750oFAccurate readingsStratificationDowncomer and duct temperatureAir inleakage

2121

Dioxin Considerations in Dioxin Considerations in Cement KilnsCement Kilns

Raw material effectsMill scale and fly ashBuild up in raw millLooking for sources of chlorinated aromaticsLaboratory test methods are challenged

2222

Dioxin Considerations in Dioxin Considerations in Cement KilnsCement Kilns

Alkali and sulfur changes in kiln systemCan affect formation mechanismUsually sufficient chlorine available for formation to occur

2323

Questions?Questions?

2424