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Rod Hatt

859-873-0188rod_hatt@coalcombustion.com

Its the coal

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Measuring Coal Quality

ASTM only produces

average data

Power plants respond to

swings in quality

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Whatmakes

coal

peopledifferent

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0

10

20

30

40

50

60

1 2 3 4 5

Pure Coal Analyses

AshWhat is Easy to sell What causes plant

problems

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Lowest cost coalis always raw.

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0

10

20

30

40

50

60

1 2 3 4 5 6 7 8 9

ASTM reports same ash level

Small and Large Variability

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Nuclear On Line AnalyzersOver the belt

Most Measures Ash and Sulfur

Chemistry

This is valuable informationMeasures chemistry

not Moisture, Btu/lb

Needs regular calibrationNeeds prior knowledge of coal

Good for coal mining industry

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New technology measures

Carbon and OxygenNo Prior Knowledge of Coal

Maybe this or some other

analyzer that measuresC, O will provide what

power plants and buyers need

Now we can measurevariability in coal quality

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Does this coal met spec?

5.7

6.1

Average

Plant Limit

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CCI promotes

Training Action - Plansand software for

Power Plants to useOn-Line

and other

Coal Qualityinformation

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Ash Btu

0

1 0 0 0

2 0 0 0

3 0 0 0

4 0 0 0

0 0 0

6 0 0 0

7 0 0 0

8 0 0 0

9 0 0 0

0 20 40 60 80% Ash

Btu/L

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SlagRelated to:

Coal Quality Getting Worse?

Plant Equipment Boiler/Mills Fixed

Combustion Process -

This we can control:

SuperiorMill Performance

Maintain Mills to Preserve

BOILER Lower F.O.R.

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FeS2

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SO2 vs Fe2O3

0.1

1.1

2.1

3.1

4.1

5.1

6.1

7.1

0 2 4 6 8 10

SO2/MBto

Fe2O3/M

B

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Waterwall Corrosion Tube Leaks

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PulverizersCoal Flow

Air Flow

Coal Pipe VelocityOutlet Temperature

Coal Fineness

Reject Material

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Ash Wears Them Out

Impacts load

High Maintenance

Performance Testing

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Pulverizer Performance

70 % passing a 200 mesh screen

MinimumorMaximum

Need 75% for high pyrite low NOx

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SiO2 Fe2O3

Al2O3 CaO

TiO2 MgO

K2O

Na2O

Acid Oxides Basic Oxides

Glass Formers Fluxes

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Acid Base

Fe2O3 FeOFe3O4

Oxidized Reduced

Good Poor

Role of Iron

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Slag Index = dry S x B/A

= dry S (~1/3 to 2/3 pyrite) x B/A= dry S (FeS2)xFe2O3+CaO+/SiO2+

Traditional Slagging Index

SI ~ (Fe)2 (iron squared)

This means that as sulfur increases theslagging increases exponentially.

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FEGTFurnace Exit Gas Temp

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0

5

10

15

20

25

30

35

40

45

Wo

od

Lign

ite

PRB

IllBitum

in.

CAPP/NA

PP

MAF Oxygen

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COAL-O-

-O-

-O-

Organically Bound Alkalis

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Ash CaO

0

5

10

15

20

25

30

35

40

0 10 20 30 40 50 60 70 80

% Ash

%Ca

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Lbs. of ash/MBtu

= %ash / (Btu/10,000)

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Lbs. of element/MBtu

= %ash / (Btu/10,000)

X (%Element/100)

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Many slagging concerns

have been addressed using

Ash Loading and Elementalloading levels; especially

Fe2O3, CaO, Na2O

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Thank you!