1. FGD, SCR, & Other Retrofit NOx Controls FGD, SCR, & Other Retrofit NOx Controls Presented by: Joe Ennis, Director Project Engineering APP Site Visit October 30 – November 4, 2006

2. 2 FGD Retrofit Program Current Program includes 10 Units Totaling 8400 MWs Construction Timeline is late 2006 through 2010 FGD Limestone Based Technologies include Spray Tower, Spray/Tray Tower and Jet Bubbling Reactor Key Design Parameters and Project Goals –98% SO2 Removal with 99% Reliability –Fuel Flexibility Sulfur Content Ranges from 2.7% to 4.5% –Disposal and Wallboard Quality Gypsum (site dependent) –Alloy 2205 and 255 Absorber Construction; FRP Internals with Jet Bubbling Reactor –Less than 10 ppm SO3 at Stack Outlet –Convert to Balanced Draft Steam Generator Operation –Limestone Quality from 88 to 95% Calcium Carbonate

3. 3 FGD Retrofit Program Additional Design and Equipment Parameters –Single Absorber Module up to 800 MW –SO3 Absorber Capture 30 to 40% –Wastewater Treatment System for Chloride Purge Stream Treatment –Redundant Ball Mills, Spare Vacuum Filters and Recycle Pumps –Saturated Exit gas at 130F –900ft+ Tall FRP Lined Stacks –Axial Flow ID Fans Up to 19,000 HP –Dry Sorbent Injection for SO3 Control Upstream of Precipitators –8+ miles of Conveying Systems to Handle 360 tph limestone and 540 tph gypsum

4. 4 Typical Spray/Tray Tower Module

5. 5 Typical Jet Bubbling Reactor Flow

6. 6 Typical Jet Bubbling Reactor Detail

7. 7 SCR Retrofit Program Current Program includes 3 Units Totaling 2380 MWs Construction Timeline is late 2006 through 2009 Key Design Parameters –90% NOx Removal Over the Unit Load Range –Inlet NOx Concentration 0.60 lb per 10^6 BTU –99+ % Reliability –No Reactor Bypass –Static Ammonia Mixers –On Site Ammonia Production –Less 2 ppm Ammonia Slip at 16,000 Service Hours –SO2 to SO3 Conversion of 0.65%

8. 8 Typical Static Mixing SCR

9. 9 FGD, SCR and Other Retrofit NOx Controls QUESTIONS????