Oct 28, 2003 ... Coal Ash Beneficiation for. Quality Construction Materials and Sustainability.
NETL 2003 Conference on. Unburned Carbon on Utility Fly Ash.
Coal Ash Beneficiation for Quality Construction Materials and Sustainability NETL 2003 Conference on Unburned Carbon on Utility Fly Ash October 28, 2003 Pittsburgh, PA
2002 CCP’s Utilization (Tons) ! ! ! ! ! !
Concrete 190,000 Waste Stabilization 170,000 Supplemental Fuel 131,000 Sub-Base (Btm. Ash) 130,000 Cement Raw Feed 30,000 Soil/Asphalt Stabilization 12,000 Total
663,000
We Energies CCP Production & Utilization 800,000
700,000
600,000
400,000
300,000
200,000
Coal Ash Produced (Tons) Coal Ash Utilized (Tons)
100,000
0 19 80 19 81 19 82 19 83 19 84 19 85 19 86 19 87 19 88 19 89 19 90 19 91 19 92 19 93 19 94 19 95 19 96 19 97 19 98 19 99 20 00 20 01 20 02 20 03 20 04 20 05
Tons
500,000
Quality Management !Environmental
Regulations !User Specifications !Chemistry !Physical !Storage - Shelf Life
Quality of CCP’s ! Importance
of Consistency
– Loss on Ignition (LOI) – Foam Index – Chemistry (Coal Changes) – Fineness (Mill Performance) !
Ash Sample Requests – Quality Record – Outside Research
Lower Quality CCP’s? !No
Users? !Solution = Change the CCP to a material that is needed and can be beneficially used.
Why Beneficiate? ! Economics ! Quality
Enhancement ! More Revenue ! Avoid Landfilling and Expense ! Sustainability
Carbon (LOI) Reduction ! Ash
Fuel Reburn ! Fluidized Bed Combustion ! Electrostatic Seperation ! Froth Floatation
Ash Fuel Reburn Process
Patent # 5,992,336
Valley Power Plant
•Located near downtown Milwaukee •Responsible for 280 megawatts of power for the downtown area •Provides all of the steam for the district heating system •Fly Ash has LOI near 25 %, bottom ash has LOI near 50 %
Pleasant Prairie Power Plant
! ! ! !
Wisconsin’s largest power plant (2 units) Located near Wisconsin-Illinois border Serves as baseload plant for system Fly ash has LOI of less than 1%
Old System
Power Plant Coal
Landfill
Coal
Virgin Ash From Other Plants
New System Energy
Power Plant Building Materials
Wet Process
Dry Process
Test Burn Results " Bottom
Ash VAPP LOI In = 37.9% PPPP LOI Out = 0.3% " Fly Ash VAPP LOI In = 26.5% PPPP LOI Out = 0.3%
Benefits " Recover
Otherwise Lost Energy " Preserve Existing Landfill Capacity " Reduce Need for New Landfills " Provide Additional Improved Fly Ash for Concrete " Reduce Additional CO2 and other Emissions from Cement Production " Avoided Cost of Landfilling
Recovering Ash Stored In Landfills
Coal fired power plants have existed for several decades, but only recently has ash utilization become prominent. The question is, where is all the ash from years past?
In Landfills!
Licensing and constructing landfills is becoming less attractive as an option because: #There is less space for new construction of landfills #Increased regulations make landfills more expensive to license and build #People do not want landfills to be built near their homes or businesses
In addition to the expense of building and maintaining landfills, hundreds of thousands of acres of landfills contain significant amounts of ash that either was not or could not be utilized. Much of this ash has a high L.O.I. value, and is therefore
WASTED ENERGY
Ash Recovery Process (Patent #6,637,354)
Construction Materials Coal
Pleasant Prairie Power Plant
Energy
Stored Ash Environmental Benefits
Ash Reclamation at Former Landfill Site
By reclaiming, reburning, and treating ash from landfills: $Landfill space is reclaimed and is available for more productive uses $Energy is recovered $Concrete quality fly ash is produced $Raw fuel is conserved for future generations
Other Benefits Include: !
Reduced Risk to Soil/Groundwater
!
Allows Redevelopment of Former Landfills
!
Reduced Mining and Transportation of Coal
!
!
Reduced Limestone and Clay Quarried for Portland Cement Production Reduced Emissions from Cement Kilns – CO2, NOx, HCl, SOx Higher Quality/Strength Concrete
!
Production of Product Close to Market
!
P4 Ash Fuel Reburn Results
Reburn Statistics P4
Ash Reburned (tons)
Coal Fly ash Displaced produced (tons) (tons)
280,000
120,000
125,000
2,500
4,500
PIPP 10,000
Ash Fuel Blending ! Coal
typically has 5% Ash Content ! High Carbon Supplemental Fuel has 80% Ash Content ! For 2% Ash Fuel Addition: Resulting Coal Ash Influence = (.98 X .05) + (.02 X .80) .049 + .016 = .065 So for .016/.065 we have 25% influence in total ash by adding 2% Ash Fuel.
CaO vs. Ash Fuel Addition Trend 7.00
27.00 26.00
6.00
25.00 24.00
5.00
CaO (%)
23.00 22.00
4.00
21.00 3.00
20.00 19.00
2.00
18.00 17.00
CaO (% )
16.00
Ash Fuel Addition (% )
1.00
15.00 00 0 2 / 1/1
0.00 00 0 2 / 9/7
5/1
00 2 / 5
1 1/2
00 2 / 0
2 9/2
00 2 / 7
2
Fly Ash Characterists for P4 Ash Fuel 7.00 6.00
100.0
5.00
90.0
4.00 80.0 3.00 70.0
2.00
60.0
1.00
50.0
0.00
00 0 2 / 1/1
00 0 2 / 9/7
5/1
SiO2 + Al2O3 + Fe2O3 (% )
00 5/ 2
1 1/2
00 0/ 2
2 9/2
00 7/ 2
2
7 Day SAI, (% of Control)
03 0 2 / 6/4
Ash Fuel Addition (% )
Ash Fuel Addition
SiO2 + Al2O3 + Fe2O3 and SAI
110.0
LOI, Equivalent Na2O, Density, Ash Fuel Addition
Fly Ash Characterists for P4 Ash Fuel 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 1
0 00 2 / /1
LOI (% )
9
0 00 2 / /7
5/1
00 5/ 2
1
Equivalent Na2O (% )
1/2
00 0/ 2
2 9/2
00 7/ 2
2
Ash Fuel Addition (% )
6
3 00 2 / /4
Density, g/cm3
Conclusions " “The
Right Thing to Do.”
– Environment – Cement Industry – Utility Customers – Utility Stockholders – Global Community – Sustainable Development for the Future
