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Presented to the 2003 Annual ACERC Conference Salt Lake City, UT February 20, 2003. Mercury Control for Power Plants. Arun Mehta, George Offen, Ramsay Chang, Richard Rhudy. EPRI Mercury Control R&D Program.
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Presented to the 2003 Annual ACERC Conference Salt Lake City, UT February 20, 2003 Mercury Control for Power Plants Arun Mehta, George Offen, Ramsay Chang, Richard Rhudy
EPRI Mercury Control R&D Program • Program started with developing understanding of factors affecting mercury emissions • Studies of flue gas parameters controlling the effectiveness of control strategies • Development & demonstration of a range of options
Key Partners • Power Producers Allegheny, Cinergy, Duke Power, First Energy, GRE, LG&E, Minnesota Power, MidAmercan Energy Co, NIPSCo, Ontario Power Generation, PG&E NEG, PSEG, Southern Company, TVA, TXU, We Energies, Xcel • Agencies NETL/DOE, EPA, ICCI, NDIC • Contractors and Laboratories ADA-ES, Apogee, EERC, ISGS, URS • Suppliers • Hamon RC, Norit, EnviroCare, EEC
Mercury Reductions for Power Plants – Performance Overview -- Bituminous • 20-95%, depending on NOx, SO2 control • SD/BH or SCR/FGD with high Cl highest Hg • Options to increase Hg removal • Activated carbon injection (ACI) furthest developed • Oxidation catalysts or chemical additives may increase capture by SO2 controls – under development • SCR catalyst age and size may not be critical factors (?) • Re-emissions is growing concern
Mercury Reductions for Power Plants – Performance Overview – Low Rank Coals • Typically Hg < 25% • Includes plants with SO2 control • ACI again furthest developed, but • Ahead of ESP < 60-70% • Ahead of FF??? Tests planned 2003 • SD/BH impedes ACI performance • Possible solutions • Oxidation catalysts ahead of SO2 control • Chemical additives to enhance capture in SO2 control or via ACI • Fixed structures coated with sorptive material
Full-scale ACI Test Sites *DOE-NETL PRDA Projects
Field Results – Hg By ACI Ahead of ESPs 90 80 Full-Scale Test (Lo S Bit) Full-Scale Test (PRB) 70 60 50 Hg Removal (%) Full-Scale Test (Hi S Bit) 40 30 Pilot Sites (8) 20 $7M/yr for 500MW 10 0 0 5 10 15 20 25 30 Injection Concentration (lb/Macf)
SD-BH ReducedEffectiveness of ACI 100 Average BH 90 80 70 FGD, SD + BH 60 HOK, SD + BH % Hg Removal 50 LAC, SD + BH 40 IAC, SD + BH 30 20 10 0 0 2 4 6 8 Injection Concentration (lb/MMacf)
Mercury Removal Across Wet Scrubber Dependent on Salt Chemical Type • Potential impacts • Air heater pluggage • Opacity increase • Scrubber water chloride increase
Carbon honeycomb Parallel Plates with sorbent surface Gas Flow MerCAPTM Concepts • Currently focusing on post SD/BH with W. fuels • 10’ plates believe 90% Hg • Developmental technology
Mercury Control: What Next?Next? • Long-term (3 months to one year) full-scale ACI tests (withNETL/DOE) • EPRI actively seeking partners – hosts and contractors • Short-term full-scale ACI/chemical injection tests on western fuels • Emerging technologies (some with NETL/DOE) • Chemical additives • MerCAP™ and other fixed structures/beds • Novel sorbents (from EPA, EPRI, others) • Mercury oxidation catalyst field pilot testing • Other concepts, IECs?