Illinois Basin Coal Issues

AEP BRO Forum 2013

7/30/2013

By Pat Malone

Where is the ILB Region

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NorthernAppalachian

CentralAppalachian

Illinois Basin

Powder River Basin

CO/UT UintaBasin

• 12,000 to 13,000 BTU/lb• 4 to 7 lb SO2/mmBTU• low fusion ash• Rail and Barge access

• 11,800 to 12,400 BTU/lb• 0.8 to 2 lb SO2/mmBTU• medium to high fusion ash

• 8000 to 9000 BTU/lb• 0.5 to 1.1 lb SO2/mmBTU• low fusion ash• Rail Transportation to the East

• 11,000 to 12,200 BTU/lb• 1.8 to 5.5 lb SO2/mmBTU• low fusion ash• 0 to 0.5% Chlorine

• 11,000 to 12,300 BTU/lb• 0.8 to 1.5 lb SO2/mmBTU• high fusion ash• Limited Rail

Texas Lignite• 6.000 to 7,000 BTU/lb• 2 to 3.5 lb SO2/mmBTU• low fusion ash• Mine Mouth Plants

Why ILB?

• Proximity to AEP facilities, reduces shipping costs

• The ILB is accessible from the Ohio River, and the Mississippi

• Aspects of ILB fuels make it a cheaper fuel.• Chlorine Content

• Sulfur Content

• Low Fusion Ash

• ILB as a low cost alternative to NAPP Fuel.

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Concerns with ILB

• Chlorine Content: • Fouling-high temperature bonded deposits that occur in the reheat and superheater

regions of the convection pass that are not exposed to radiation.• Fouling is determined by the amounts of alkalis in the ash, primarily sodium and potassium

compounds that vaporize during combustion and condense at approximately 1700-1500F.

• These condensed alkalis act as the glue that bonds dry ash particles together.

• Sodium chloride is very active and indicates a fuel with potentially high fouling tendencies. The chlorine is an indicator of the amount of sodium.

• Fouling reduces heat transfer, and causes channeling of high velocity gas that erodes the boiler tubes.

• High fouling coals should only be used in boilers with wide convection pass spacing, and adequate soot blowing.

• Corrosion-chlorine is a halogen and a very good oxidizer. • Furnace tube wastage especially with staged combustion (reducing). Supercritical steam generators

worse than subcriticals due to tube metal temperatures.

• Stainless Steel Superheaters

• FGD stainless steel components

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Predicting Fouling Tendencies of Coal

Low Medium High Severe

% Na2O in Ash < 1.0 1.0 - 3.0 3.0 - 4.0 > 4.0

Base/Acid Ratio x Na2O (High Temp. Ash)

< 0.2 0.2 - 0.50 0.50 - 1.0 > 1.0

% Alkali as Na2O in dry coal

< 0.3 0.3 - 0.45 0.45 - 0.6 > 0.6

% Chlorine in coal < 0.2 0.2 - 0.3 0.3 - 0.5 > 0.5

Active Na2O (weak acid soluble)

2.0 - 2.5 > 4.0

Base/Acid Ratio x Na2O (water soluble)

< 0.1 0.1 - 0.25 0.25 - 0.7 > 0.7

Blending

AEP currently limits Fuel Source Chlorine to 0.2% by weight.• We have completed test burns at a number of facilities that have blending capability

and were able to maintain a blend of ILB/Ea. Bit.

• Successfully staying below the 0.2% Cl limit

• We are comfortable with the “supervised” use of ILB coals

• Blending with PRB is difficult because of the sodium in the PRB.

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QUESTIONS?

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