Performance and Benefits of Flue Gas Treatment Using Thiosorbic Lime Presented by Carmeuse North America Carmeuse North America makes no warranty or representation, expressed or implied, and assumes no liability with respect to the use of, or damages resulting from the use of, any information, apparatus, method or process disclosed in this document.

BACKGROUND ON CARMEUSE

Carmeuse North America - Background 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

Lime Plant Locations in U.S. and Canada - Background Lime Plant Locations in U.S. and Canada testing Carmeuse While Carmeuse North America is the leading supplier, FGD lime is widely available North America plant locations

Carmeuse Provides: - Background 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

BENEFITS OF THE THIOSORBIC FGD PROCESS - Thiosorbic® Process BENEFITS OF THE THIOSORBIC FGD PROCESS

Benefits of Thiosorbic FGD process - Thiosorbic® 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

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

Thiosorbic FGD Process Description - Thiosorbic® Process 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

Thiosorbic FGD Process - Thiosorbic® Process Thiosorbic FGD Process

FGD Process Comparison: Thiosorbic vs FGD Process Comparison: Thiosorbic vs. Limestone Forced Oxidation (LSFO) - Thiosorbic® Process 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

Comparison of Gypsum from Thiosorbic Lime with LSFO Gypsum - Thiosorbic® Process Comparison of Gypsum from Thiosorbic Lime with LSFO Gypsum

FGD Process Comparison: Thiosorbic vs. LSFO - Thiosorbic® Process 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

FGD Process Comparison: Absorber Size - Thiosorbic® Process These absorbers were supplied by the same FGD equipment supplier at two different sites. The difference in height is due solely to FGD process type. LSFO requires more absorber spray headers, greater L/G, more recirculation pumps, and a larger hold time in the recirculation tank, leading to a substantially taller, more costly absorber. LSFO 125 ft 38.1 m Thiosorbic 55 ft 16.8 m

Thiosorbic Absorber at Zimmer Station 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

Thiosorbic Absorber At HMPL Station #2 Example of compact absorber Wheelabrator design Only 46 ft high (grade to top tangent line) One operating recycle pump, one spare Design L/G is 30 gal/1000 acfm (4 l/m3) for 95% SO2 removal Achieved 96% SO2 removal in 1994 performance test on 3% sulfur coal

BENEFITS OF BYPRODUCT MAGNESIUM HYDROXIDE FROM THE THIOSORBIC PROCESS - Byproduct Mg(OH)2 from the Thiosorbic® Process BENEFITS OF BYPRODUCT MAGNESIUM HYDROXIDE FROM THE THIOSORBIC PROCESS

Thiosorbic FGD Process with Byproduct Mg(OH)2 Production

Benefits of Byproduct Magnesium Hydroxide - Byproduct Mg(OH)2 from the Thiosorbic® Process 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

Mg(OH)2 Injection for SO3 Control - Byproduct Mg(OH)2 from the Thiosorbic® Process Mg(OH)2 Injection Location Furnace Selective Catalytic Reduction ESP Thiosorbic FGD

Furnace SO3 Removal vs. Mg:SO3 Ratio in 1300 MW Boiler - Byproduct Mg(OH)2 from the Thiosorbic® Process Furnace SO3 Removal vs. Mg:SO3 Ratio in 1300 MW Boiler 100% 90% 80% 70% 60% 50% Full-scale demonstration of SO3 control with Thiosorbic byproduct Mg(OH)2 Full-scale demonstration of SO3 control with Thiosorbic byproduct Mg(OH)2 40% 30% 20% 10% 0% 1 2 3 4 5 6 7 8 Mg:SO3 Ratio

Reduction in Visible Opacity with By-product Mg(OH)2 Treatment - Byproduct Mg(OH)2 from the Thiosorbic® Process Reduction in Visible Opacity with By-product Mg(OH)2 Treatment Untreated Treated

Benefits of Byproduct Magnesium Hydroxide - Byproduct Mg(OH)2 from the Thiosorbic® Process 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

Benefits of Byproduct Magnesium Hydroxide - Byproduct Mg(OH)2 from the Thiosorbic® Process 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

Full-scale Application of Byproduct Mg(OH)2 Injection for SO3 Control - Byproduct Mg(OH)2 from the Thiosorbic® Process Full-scale Application of Byproduct Mg(OH)2 Injection for SO3 Control A 1400 MW installation begins operation 1st quarter 2004

Potential Cost Savings from Furnace Injection of Magnesium Hydroxide - Byproduct Mg(OH)2 from the Thiosorbic® Process 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

- Byproduct Mg(OH)2 from the Thiosorbic® Process Factors Used to Determine Cost Benefits of Boiler Injection of Byproduct Mg(OH)2 - Byproduct Mg(OH)2 from the Thiosorbic® Process

- Byproduct Mg(OH)2 from the Thiosorbic® Process Lower Life Cycle Cost with Thiosorbic Process and Byproduct Mg(OH)2 Compared with LSFO 40 base case 35 Increased availability & furnace efficiency Increased availability & furnace efficiency, reduced fuel cost 30 Increasing cost competitiveness of Thiosorbic process Lower life cycle cost for Thiosorbic process in area above each line 25 Limestone cost, $/ton 20 15 10 Based on 3% sulfur bituminous coal 5 40 45 50 55 60 65 70 Lime cost, $/ton

HYDRATED LIME INJECTION FOR SO3 CONTROL - Hydrated Lime for SO3 Control HYDRATED LIME INJECTION FOR SO3 CONTROL

Ca(OH)2 Injection for SO3 Control - Hydrated Lime 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

Ca(OH)2 Injection for SO3 Control - Hydrated Lime for SO3 Control Ca(OH)2 Injection Locations Selective Catalytic Reduction Furnace ESP Thiosorbic FGD

Ca(OH)2 Injection for SO3 Control - Hydrated Lime 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

Performance and Benefits of Flue Gas Treatment Using Thiosorbic Lime Conclusions: 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