Coal Flow Strategies for Electric Utilities

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 moistureIn General:

Surface Moisture Properties0-4% More Dusty4-6% Dusty & Sticky>6% More Sticky

But, please remember coal characteristics vary considerably


• 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


• 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


– Stack out & storage (problem?)


– Cover storage areas if possible


– Particle size


– Encapsulation agents


– Material Selection• Generally smoother wall surfaces result in lower wall

friction.• Materials that prevent corrosion (SST, Plastics)


– Mechanical


– 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


– 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


– Samples Taken / Evaluation Performed– Real Time Dosages Estimated from data

http://lasanyinternational.trustpass.alibaba.com/productshowimg/104482209-100741029/DIGITAL_AUTOMATIC_TAP_DENSITY_TEST_APPARATUS.html


– Typical dosages between 0.1 and 1.0lb/ton– Treatment optimized based on real-time moisture

and rain data


– Rain and coal moisture analyzed

Thanks

Coal Flow Strategies for Electric Utilities

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