Dry Bottom Ash HandlingOptions & New Technology

World of Coal Ash Conference 2009

2009 World of Coal Ash (WOCA) Conference - May 4-7, 2009 in Lexington, KY, USA http://ww.flyash.info/

Elimination of Fly Ash from Ash Ponds –Options & Advantagesp g

• Vacuum System to SiloN h d i i ti i t k• No changes under precip, uses existing intakes

• Limit on conveying capacity vs. distance

• Dilute Pressure System to SiloDilute Pressure System to Silo• Most Pressure Systems are “Dry”

V /P T f S t t Sil• Vacuum/Pressure Transfer System to Silo• Use existing ash intakes• No limit on conveying capacity and distance

• Dense Pressure to Silo• Can replace vacuum system• Limit on conveying capacity and distance

Dry Fly Ash Conveying –Dilute/Dense Flow Regimes g

Dry Fly Ash Conveying –Capacity vs. Distance p y

Dry Fly Ash Conveying –Vacuum System to Siloy

Dry Fly Ash Conveying –Pressure System – Most Already Dry y y y

Dry Fly Ash Conveying –Vacuum/Pressure Transfer Station 

Dry Fly Ash Conveying –Vacuum/Pressure Transfer Station 

Dry Fly Ash Conveying –Enclosed Vacuum/Pressure Transfer Station 

Dry Fly Ash Conveying –Vacuum/Pressure Transfer Silo 

Dry Fly Ash Conveying‐Vacuum/Pressure Transfer Silo Installation 

Dry Fly Ash Conveying –Pressure Feeders Under Transfer Silo 

Dry Fly Ash Conveying –Pressure Feeders Under Transfer Silo 

Dry Fly Ash Conveying –Pressure Line to Remote Silo 

Dry Fly Ash –Dense Phase Pressure – Can Replace Vacuum Systemp y

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Dry Bottom Ash Conveying 

1940’s‐1950’s: UCC develops dry bottom ash conveying 

®with NUVEYOR® pneumatic ash conveying systems, gravity discharge ash pit g y g phoppers.

Rendition of a UCC NUVEYOR system for a utility boiler, including gravity discharge ash pit hopper.

Dry Bottom Ash Conveying –Temperature p

Dry Bottom Ash Conveying –Slag Falls g

Elimination of Bottom Ash from Ash Ponds –Options & Advantagesp g

• Re‐Circulating Water System• No changes under boiler uses existing hopper• No changes under boiler, uses existing hopper• Switch to new system in 3 day outage

• Submerged Flight Conveyor – SFCg g y• Most economical choice• Simple solution if space is available

i C i• Dry Hopper Pneumatic Conveying – PAX• No water, returns heat back to boiler• Easiest 100% dry option to get out of boiler building

• Vibratory Conveying – VAX• No water, returns the most heat back to boiler• Continuous removal of bottom ash

Dry Bottom Ash – Re‐Circulation System

Dry Bottom Ash – Re‐Circulation System

Dry Bottom Ash ‐ SFC

Dry Bottom Ash ‐ SFC

Dry Bottom Ash ‐ SFC

Dry Bottom Ash ‐ PAX System

Dry Bottom Ash ‐ PAX System

Dry Bottom Ash ‐ VAX

Dry Bottom Ash ‐ VAX

Dry Bottom Ash ‐ VAX

Dry Bottom Ash –Features Comparisonp

Re‐Circ Tanks SFC  PAX  VAX 

CostsDesign and material Costs $5 M $2 M  $3.5 M  $3.5 M 

CostsInstallation Cost $4.5 M $1.5 M $3.5 M  $2.5 M

Pre‐Outage Construction 6 months 2 months 2 months 2 months

Outage  Requirement

Duration6 months 2 months 2 months 2 months

Outage Construction 3 days 3 weeks  8 weeks 6 weeks

Outage Start‐Up 2 ‐ 3 days 1 ‐ 2 days 3 ‐ 4 days 1 ‐ 2 days

Lead Time 9 months 9 months  12 months  12 months 

Dry Bottom Ash –Features Comparisonp

Re Circ Tanks SFC PAX VAXRe‐Circ Tanks SFC  PAX  VAX 

Yard Piping Corridor Yes No Yes No

Boiler & Yard SpaceBoiler House Exit Corridor for Mechanical Conveyor

No Yes No Yes

Yard Foot Print 6500 sq ft 1500 sq ft 1500 sq ft 1000 sq ft

Storage Bin Serves moreMultiple Unit synergies

Storage Bin Serves more than one boiler

Yes No Yes No

Dry Bottom Ash –Features Comparisonp

Re‐circ Tanks SFC  PAX  VAX 

High Pressure Pumps Yes No No No

Vacuum/Pressure Blowers

No No Yes No

O ti d M i t

Refractory Yes ‐ existingUsually none

YesUsually none

Yes ‐Operations and Maintenance Costs

Conveyor Chain Replacement

No Yes NoYes 

Secondary Conveyor

CrushersYes ‐ existing 

(3)Usually none

Yes (3) Yes (1)

ConveyingConveying pipeline/valves

Yes No Yes  No

Dry Bottom Ash –Features Comparison

Re Circ Tanks SFC PAX VAX

p

Re‐Circ Tanks SFC  PAX  VAX 

Make‐up water 100 gpm 50 gpm None None

Cooling Water 400 gpm 400 gpm None NoneWater Consumption

Cooling Water 400 gpm 400 gpm None None

Conveying Water (re‐circulating)

2500 gpm None None None

Power Consumption

Pumps 600 HP 50 HP None None

Blowers/Fans None None 200 HP 50 HPPower Consumption Blowers/Fans None None 200 HP 50 HP

Mechanical Drives 50 HP 100 HP 50 HP 75 HP

Dry Bottom Ash Decision Analysis

Technology AlternativesTechnology Alternatives

1 = Worst, 5 = Best Scale 1-5 Re-Circ System SFC PAX VAX

Criteria for Determing Technology Selection WT SC Total SC Total SC Total SC Total

Water Usage/Availability 0 2 0 3 0 5 0 5 0Outage Time Available 0 5 0 4 0 2 0 3 0Total Installed Cost 0 1 0 5 0 3 0 3 0Total Installed Cost 0 1 0 5 0 3 0 3 0Operation & Maintenance Cost 0 2 0 5 0 3 0 4 0Power Consumption 0 1 0 4 0 2 0 5 0Boiler House Corridor Availability 0 5 0 3 0 5 0 3 0Boiler House Corridor Availability 0 5 0 3 0 5 0 3 0Multiple Unit Synergies 0 5 0 2 0 4 0 2 0

Weighted Total Score 0 0 0 0

Decision Analysis Favors Re‐Circulation System

Technology AlternativesTechnology Alternatives

1 = Worst, 5 = Best Scale 1-5 Re-Circ System SFC PAX VAX

Criteria for Determing Technology Selection WT SCTotal SCTotal SCTotal SC Totalg gy

Water Usage/Availability 2 2 4 3 6 5 10 5 10Outage Time Available 5 5 25 4 20 2 10 3 15Total Installed CostTotal Installed Cost 2 1 2 5 10 3 6 3 6Operation & Maintenance Cost 2 2 4 5 10 3 6 4 8Power Consumption 2 1 2 4 8 2 4 5 10Boiler House Corridor Availability 5 5 25 3 15 5 25 3 15Boiler House Corridor Availability 5 5 25 3 15 5 25 3 15Multiple Unit Synergies 5 5 25 2 10 4 20 2 10

Weighted Total Score 87 79 81 74

Decision Analysis Favors SFC System

Technology AlternativesTechnology Alternatives

1 = Worst, 5 = Best Scale 1-5 Re-Circ System SFC PAX VAX

Criteria for Determing Technology Selection WT SCTotal SCTotal SCTotal SC Total

Water Usage/Availability 4 2 8 3 12 5 20 5 20Outage Time Available 5 5 25 4 20 2 10 3 15Total Installed CostTotal Installed Cost 4 1 4 5 20 3 12 3 12Operation & Maintenance Cost 3 2 6 5 15 3 9 4 12Power Consumption 2 1 2 4 8 2 4 5 10Boiler Ho se Corridor A ailabilitBoiler House Corridor Availability 1 5 5 3 3 5 5 3 3Multiple Unit Synergies 1 5 5 2 2 4 4 2 2

Weighted Total Score 55 80 64 74

Decision Analysis Favors PAX System

Technology AlternativesTechnology Alternatives

1 = Worst, 5 = Best Scale 1-5 Re-Circ System SFC PAX VAX

Criteria for Determing Technology Selection WT SCTotal SCTotal SCTotal SC Totalg gy

Water Usage/Availability 5 2 10 3 15 5 25 5 25Outage Time Available 1 5 5 4 4 2 2 3 3T t l I t ll d C tTotal Installed Cost 3 1 3 5 15 3 9 3 9Operation & Maintenance Cost 3 2 6 5 15 3 9 4 12Power Consumption 3 1 3 4 12 2 6 5 15Boiler House Corridor Availability 5 5 25 3 15 5 25 3 15Multiple Unit Synergies 5 5 25 2 10 4 20 2 10

Weighted Total Score 77 86 96 89

Decision Analysis Favors VAX System

T h l Alt tiTechnology Alternatives

1 = Worst, 5 = Best Scale 1-5 Re-Circ System SFC PAX VAX

Criteria for Determing Technology Selection WT SCTotal SCTotal SCTotal SC TotalCriteria for Determing Technology Selection WT SCTotal SCTotal SCTotal SC Total

Water Usage/Availability 5 2 10 3 15 5 25 5 25Outage Time Available 1 5 5 4 4 2 2 3 3Total Installed Cost 3 1 3 5 15 3 9 3 9Operation & Maintenance Cost 3 2 6 5 15 3 9 4 12Power Consumption 5 1 5 4 20 2 10 5 25Boiler House Corridor Availability 2 5 10 3 6 5 10 3 6Multiple Unit Synergies 1 5 5 2 2 4 4 2 2

Weighted Total Score 44 77 69 82

Pre‐Assembly Options 

Pre‐Assembly Options 

Pre‐Assembly Options 

Thanks for Listening!

Questions?Q