Mercury Issues for Coal-Fired Power Plants: Emissions, Fate and Health Effects, Controls George Offen Technical Executive Emissions/Combustion Product Mgmt with material from Ramsay Chang, Paul Chu, Leonard Levin, Naomi Goodman Indiana Society of Mining and Reclamation Jasper, Indiana December 7, 2004

2 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Regulatory Status Two alternative approaches proposed 12/15/03 –MACT - compliance by Bituminous – 2 #/TBtu Sub-bit – 5.8 #/TBtu Lignite – 9.2 #/TBtu New source standards – more stringent –Cap-and-trade Co-benefits by 2010, 15 TPY (70% ΔHg by 2018) Allocations by states –Possible to opt out in one option Final rule delayed until 3/15/05 Hg rule + Clean Air Interstate Rule Clear Skies Act States considering/adopting stringent limits

3 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Mercury Global Anthropogenic Emissions Anthropogenic Emissions ~ 1/3 rd – 1/2 Total Emissions United States 155 U.S. utilities 48 South & Central America 194 Europe 560 Africa 271 Oceania 53 rest of North America 71 Asia 1231 Global total 2535 tons per year

4 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. U.S. mercury deposition from non-U.S. sources % contribution by non- U.S. sources, 2004

5 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Annual deposition of mercury for 2004 Base Case g/m 2 -y

6 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Annual deposition of mercury for 2020 Cap & Trade Scenario g/m 2 -y

7 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Drop in Mercury Exposure by Most-Sensitive Women (child- bearing age, high blood Hg level), 2020 Cap & Trade

8 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. How Mercury DEPOSITING in the U.S. Changes If Utility EMISSIONS Change Total Coal Plant Mercury EMISSIONS, (U.S.) tons/yr % Difference in Mercury EMISSIONS from Base Case Total Mercury DEPOSITION in the U.S. [wet + dry, Hg(tot)], T/yr, ALL MERCURY SOURCES % Difference in all U.S. Mercury DEPOSITION from Base Case Net Present Value of COSTS to Attain Stated Emissions Levels CURRENT CONDITIONS (2004 Base Case) MACT SCENARIO % %$10 billion 2020 CAP & TRADE SCENARIO % %$2 billion

9 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Mercury Basics Mercury emission levels very low –ppb or lb/TBtu levels –~250 lb/yr for 500 MW unit Generally a gas at ESP/fabric filter inlet –Elemental (metallic, Hg 0 ), –Ionic (oxidized, Hg +2 ), or –Particulate (Hg P ) Typical speciation –Powder River Basin (PRB): 75-90% Hg 0 –E. Bituminous: 60-90% Hg +2 Speciation affects controls and transport FGD captures only Hg +2 –Some captured Hg +2 may be converted to Hg 0 and re-emitted

10 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Indiana Coals < Mercury than all E.Bit* Median = 0.07 ppm or ~5.4 #/TBtu need 63% ΔHg 95% = 0.15 ppm need 83% ΔHg Source: 1999 EPA ICR Indiana All Eastern Bit. * Also < chlorine

11 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Sorbent Injection Scrubber Boiler Stack ESP/FF Coal Cleaning Additives SCR, Hg catalyst, corona Power Plant Mercury Control Options – Overview Polishing Filter (TOXECON) Fixed adsorption structures

12 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. SCR + FGD Co-benefits SCR – NOx control FGD – SO 2 control –Also captures Hg +2 SCRs may increase Hg +2 and improve overall Hg control –Removals of ~80-90+% possible for bituminous coals –~40-60% without SCR FGD chemistry may impact Hg +2 to Hg 0 conversion re- emission ~8 power plants with SCR/FGD to be tested in 2004

13 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. SCR + FGD Provide Hg Co-benefit on Bituminous Coal Plants ( PRB site has baghouse)

14 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. SCR + FGD Likely to Achieve Proposed MACT Limit for Existing Facilities; ? for New Facilities

15 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Field Results – ACI Hg Removal w/ ESPs Injection Concentration (lb/Macf) Hg Removal (%) Full-Scale Test (Lo S Bit) Full-Scale Test (Hi S Bit) Pilot Sites (8) $3.5M/yr for 500MW Full-Scale Test (PRB) Full-Scale Test (ND Lig) -Which line is correct? -Is this performance sustainable? -What are the impacts? -Are there lower-cost sorbents?

16 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Halogen Additives Improved ΔHg by AC Across SD-BH for Western Coals All short-term data ( 30 days); many questions! Corrosion Secondary emissions

17 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. TOXECON - An Option to ESP Injection Injection between ESP and polishing baghouse –Much less sorbent –No ash impacts –$45-55/kW projected AshCarbon/Hg

18 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. TOXECON Long-term Results 86% average removal at injection rate that maintains 1.5 p/b/h

19 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Mercury Measurements Ontario Hydro Method –~2 hour flue gas sample –Chemical solutions to capture Hg –ASTM; used in EPA ICR study Continuous mercury monitors (CMMs) - also SCEM –Still developmental –Measurement every 2 to 5 minutes –Must convert Hg +2 to Hg 0 before analyses QuickSEM TM – EPRI development –Basis for EPA draft method 324 –Integrated sample over hours to week+ –Uses a solid sorbent (carbon) –Simpler, more accurate, but not instantaneous readout

20 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Questions?

21 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Indiana Coals Tend to Have Less Chlorine May produce Less Oxidized Hg? Emissions data? Source: 1999 EPA ICR Indiana All Eastern Bit.

22 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Sorbent Injection Activated carbon injection (ACI) –Hg adsorbs onto carbon capture by ESP/BH –Most developed technology –Variety of carbons –Potential issues Ability to extrapolate from few test sites to full boiler population and fuels Can you sell your fly ash? Is the ash hazardous waste? Impact on ESP performance? Baghouse size, bag life?

23 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Sorbent Injection (concl.) Chemically-treated carbons new, appear promising –May be most applicable to W. coals –Early, short-term tests show % ΔHg at ¼ to 1/3 rd sorbent injection rate Halogen injection into boiler + std. AC ~ performance? Same questions as AC + potential release of halogen Non-carbon sorbents/reagents being developed –Amended silicates –Sodium tetrasulfide

24 Copyright © 2004 Electric Power Research Institute, Inc. All rights reserved. Hg Emissions Can Be Variable Comparison of Hourly and Daily Averages for 1 month Hourly Averages Daily Average