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Coal Flow Strategies for Electric Utilities
Bill Campbell Managing Partner
Water Treatment Services Inc. 8/22/12
Coal Flow Strategies for Electric Utilities• Water is the enemy
– Water adheres to the surface of small particles due to cohesive forces. The water wants to stay or stick together with other similar particles
– Crushed Coal is a small particle and is hydrophobic• Cohesive forces allow the water to stay on the surface• Hydrophobic forces prevent water from being absorbed
into the coal.
• The amount of surface moisture determines– Dustiness and Flowability characteristics
Coal Flow Strategies for Electric Utilities• Dustiness and Flowability
– Impacted by the surface moisture
In General:Surface Moisture Properties
0-4% More Dusty4-6% Dusty & Sticky>6% More Sticky
But, please remember coal characteristics vary considerably
Coal Flow Strategies for Electric Utilities
• Wet coal can cause major problems such as:– Loss of revenue
• Derates (opportunity costs)• Competitively priced electricity (penalties)
– Maintenance costs• Equipment downtime
– Operational costs• Overtime work• Safety
Coal Flow Strategies for Electric Utilities
• Strategies to improve coal flow– Proper coal handling techniques
• Proper stack out / storage techniques• Cover storage areas where possible• Particle size• Use of encapsulation agents
– Material Selection• Liners and steel choices
– Mechanical• Air blasting & vibratory methods
– Chemically• Coal flow aids
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Stack out & storage
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Stack out & storage (problem?)
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Cover storage areas if possible
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Particle size
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Encapsulation agents
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Material Selection• Generally smoother wall surfaces result in lower wall
friction.• Materials that prevent corrosion (SST, Plastics)
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Mechanical
Coal Flow Strategies for Electric Utilities• Proper Coal Handling Techniques:
– Chemical Aids
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
– Even with all the traditional methods it may not be enough
03/06/11 1754 03/07/11 0635 12.7 565.0 165.0 - 9271 wet coal (not wet coal plugged the Coal
OMC) downcomer from the
feeder to the pulverizer.
Feeder is also filled.
03/06/11 2214 03/07/11 0130 3.3 565.0 50.0 - 3113 Condenser tube Dirty river causing
and water box Condenser Tube ends
cleaning toplug up. A Mill OOS
(including due to plugged downcomer
circulating water
flow reversal)
03/07/11 0903 03/07/11 1000 1.0 565.0 115.0 - 9271 wet coal (not A' mill feeder clogged -
OMC) wet coal
03/07/11 1000 03/07/11 2232 12.5 565.0 265.0 - 9271 wet coal (not wet coal - multiple
OMC) feeders clogging
03/08/11 1330 03/08/11 1924 5.9 565.0 165.0 - 9271 wet coal (not wet coal plugging feeders
OMC)
03/08/11 1924 03/09/11 0455 9.5 565.0 50.0 - 9271 wet coal (not wet Coal and Dirty River
OMC)
03/09/11 1400 03/10/11 0308 13.1 565.0 115.0 - 9271 wet coal (not wet coal
OMC)
03/10/11 0425 03/10/11 1100 6.6 565.0 115.0 - 9271 wet coal (not wet coal plugging feeders
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
– Revenue Loses1. Data obtained from Station Event Log 2. To use sheet input the profit loss due to derate (yellow) 3. Estimated Loss is calculated by multiplying derate duration by curtailment
DR Problem Start Date
DR End Date
Duration (hours)
Max Capacity
(MW) Curtailment
(MW) MW-Hrs Curtailed
Est. Loss $
03/05/11 1900 03/06/11 0420 9.3 565.0 165.0 1534.5 $30,690 03/06/11 1754 03/07/11 0635 12.7 565.0 165.0 2095.5 $41,910 03/06/11 2214 03/07/11 0130 3.3 565.0 50.0 165 $3,300 03/07/11 0903 03/07/11 1000 1.0 565.0 115.0 115 $2,300 03/07/11 1000 03/07/11 2232 12.5 565.0 265.0 3312.5 $66,250
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
– Samples Taken / Evaluation Performed– Real Time Dosages Estimated from data
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
– Typical dosages between 0.1 and 1.0lb/ton– Treatment optimized based on real-time moisture
and rain data
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
– Rain and coal moisture analyzed
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
Coal Flow Strategies for Electric Utilities• Water Treatment Services Involvement
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