Transcript Illinois Basin Coal Issues

Illinois Basin Coal Issues
AEP BRO Forum 2013
7/30/2013
By Pat Malone
Where is the ILB Region
•
•
•
•
8000 to 9000 BTU/lb
0.5 to 1.1 lb SO2/mmBTU
low fusion ash
Rail Transportation to the East
Illinois Basin
•
•
•
•
11,000 to 12,200 BTU/lb
1.8 to 5.5 lb SO2/mmBTU
low fusion ash
0 to 0.5% Chlorine
Northern
Appalachian
•
•
•
•
•
•
•
•
CO/UT Uinta
Basin
Powder River Basin
12,000 to 13,000 BTU/lb
4 to 7 lb SO2/mmBTU
low fusion ash
Rail and Barge access
Central
Appalachian
11,000 to 12,300 BTU/lb
0.8 to 1.5 lb SO2/mmBTU
high fusion ash
Limited Rail
• 11,800 to 12,400 BTU/lb
• 0.8 to 2 lb SO2/mmBTU
• medium to high fusion ash
Texas Lignite
•
•
•
•
6.000 to 7,000 BTU/lb
2 to 3.5 lb SO2/mmBTU
low fusion ash
Mine Mouth Plants
2
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.
3
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
7
Predicting Fouling Tendencies of
Coal
% Na2O in Ash
Base/Acid Ratio x Na2O
(High Temp. Ash)
% Alkali as Na2O
in dry coal
% Chlorine in coal
Low
Medium
High
< 1.0
1.0 - 3.0
3.0 - 4.0
> 4.0
< 0.2
0.2 - 0.50
0.50 - 1.0
> 1.0
< 0.3
0.3 - 0.45
0.45 - 0.6
> 0.6
< 0.2
0.2 - 0.3
0.3 - 0.5
> 0.5
Active Na2O
(weak acid soluble)
Base/Acid Ratio x Na2O
(water soluble)
2.0 - 2.5
< 0.1
0.1 - 0.25
Severe
> 4.0
0.25 - 0.7
> 0.7
8
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.
9
QUESTIONS?
10