Performance and Benefits of Flue Gas Treatment Using Thiosorbic Lime

1. Performance and Benefits of Flue Gas Treatment Using Thiosorbic Lime Presented by Carmeuse North America

2. BACKGROUND ON CARMEUSE

3. Carmeuse North America Part of the Carmeuse Group Joint Venture of: 60% Carmeuse S.A. (Belgium) 40% Lafarge S. A. (France) Carmeuse $1 billion privately-held lime company founded in 1860 60 plants in 14 countries Lafarge $11 billion publicly-held construction materials company founded in 1833 Operations in 60 countries

4. Lime Plant Locations in U.S. and Canada testingtesting

5. Carmeuse Provides: Thiosorbic® Lime for flue gas desulfurization (FGD) in coal-fired plants Access to Thiosorbic process technology Carmeuse works in cooperation with major FGD equipment suppliers to provide the best system for the customers requirements Technical support for FGD users FGD start-up, operator training, and operations support Over 25 years experience in FGD in coal-fired power plants

6. BENEFITS OF THETHIOSORBIC FGD PROCESS

7. Benefits of Thiosorbic FGD process Ultra-low SO2 emissions with high-sulfur fuel 99% SO2 removal with high-sulfur coal Lower FGD capital cost Lower FGD power consumption Valuable by-products: wallboard-quality gypsum and magnesium hydroxide [Mg(OH)2] 25 year record of reliability 17,700 MW base of experience

8. Thiosorbic Wet FGD Applications 16 Stations – 34 Units – 17,700 MW

9. Thiosorbic FGD Process Description Wet FGD process Uses lime reagent with 3-6 wt.% MgO Mg increases SO2 removal and allows low L/G 45 L/G (gpm/1000 acfm) for 99% removal with high-sulfur fuel Low chemical scaling potential Liquid in absorber slurry only 10% gypsum-saturated

10. Thiosorbic FGD Process

11. FGD Process Comparison: Thiosorbic vs. Limestone Forced Oxidation (LSFO) Higher SO2 removal Up to 99% vs. 95% for LSFO Lower Power Consumption 1.4% versus 2.0% for LSFO for high-sulfur coal Higher Reagent Utilization 99.9% vs. up to 97% for LSFO Better Gypsum Quality 98-99% pure, bright white vs. 95%, brown or tan for limestone

12. Comparison of Gypsum from Thiosorbic Lime with LSFO Gypsum

13. FGD Process Comparison: Thiosorbic vs. LSFO Lower Capital Cost 8-12% lower capital cost Much smaller absorbers Fewer recycle pumps, fewer spray headers, smaller recirculation tank Lower maintenance cost Generate more valuable SO2 allowances

14. FGD Process Comparison: Absorber Size

15. Example of compact absorber Babcock & Wilcox design Only 54 ft high (grade to top tangent line) One operating recycle pump, one spare Design L/G is 21 gal/1000 acfm (3 l/m3) for 91% SO2 removal Achieved 96% SO2 removal in 1991 performance test on 3.5% sulfur coal

17. BENEFITS OF BYPRODUCT MAGNESIUM HYDROXIDE FROM THE THIOSORBIC PROCESS

18. Thiosorbic FGD Processwith Byproduct Mg(OH)2 Production

19. Benefits of Byproduct Magnesium Hydroxide Thiosorbic process allows option for on-site production of magnesium hydroxide Demonstrated for furnace injection and SO3 control in 800 MW and 1300 MW boilers Reduces furnace-generated SO3 emissions by 90% Substantially reduces visible plume opacity

20. Mg(OH)2 Injection for SO3 Control

21. Furnace SO3 Removal vs. Mg:SO3 Ratio in 1300 MW Boiler

22. Reduction in Visible Opacity withBy-product Mg(OH)2 Treatment

23. Benefits of Byproduct Magnesium Hydroxide Increases melting point of boiler slag Reduces strength of slag deposits; increases friability and fracture for ease of removal Increases boiler efficiency Cleaner heat transfer surfaces Allows lower air heater outlet temperature

24. Benefits of Byproduct Magnesium Hydroxide Provides FGD wastewater treatment: As, Cd, Pb, Ni, Hg below detection limits Reduces size and operating costs of wastewater treatment system; no TSS removal and coagulation/lime precipitation steps required; no BOD (DBA) removal Eliminates disposal of (RCRA-unexcluded) wastewater treatment sludge; allows co-mangement via return to furnace and combination with flyash

25. Full-scale Application of Byproduct Mg(OH)2 Injection for SO3 Control A 1400 MW installation begins operation 1st quarter 2004

26. Potential Cost Savings from Furnace Injection of Magnesium Hydroxide Increase in plant efficiency due to cleaner boiler tubes and low acid dew point: 1% increase per 35 F lower air heater exit temperature Coal savings due to use of lower temperature ash fusion coal

27. Factors Used to Determine Cost Benefits of Boiler Injection of Byproduct Mg(OH)2

28. Lower Life Cycle Cost with Thiosorbic Process and Byproduct Mg(OH)2 Compared with LSFO

29. HYDRATED LIME INJECTIONFOR SO3 CONTROL

30. Ca(OH)2 Injection for SO3 Control Hydrated lime [Ca(OH)2] has been demonstrated at 1300 MW for control of SO3 emissions after selective catalytic reduction (SCR) Hydrated lime powder can be injected into flue gas immediately after the air heater and before the particulate collector, or injected after the particulate collector and before the Thiosorbic FGD system

31. Ca(OH)2 Injection for SO3 Control

32. Ca(OH)2 Injection for SO3 Control Hydrated lime injected before the particulate collector (e.g. ESP) is removed with fly ash Hydrated lime injected before the Thiosorbic FGD system is removed by impingement with absorber spays Results in complete utilization of the hydrated lime which substantially reduces reagent cost for SO3 control 90% removal of SCR-generated SO3 is possible at Ca:SO3 molar ratio of 8

33. Performance and Benefits of Flue Gas Treatment Using Thiosorbic LimeConclusions: The Thiosorbic process is a widely utilized FGD process with a 25 record of successful operation The Thiosorbic lime FGD process provides better SO2 removal performance than the LSFO process The Thiosorbic process allows lower FGD capital cost, lower power consumption, and lower life cycle cost than the LSFO process Byproduct Mg(OH)2 provides efficient control of furnace SO3 emissions and additional operating benefits and cost savings Hydrated lime provides efficient, low-cost control of SO3 formed during SCR