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BACT Issues – A Technical Perspective. Presented to: American Public Power Association APPA New Generation Meeting: Anticipating New Permitting Issues, IGCC Technology Options, Atmospheric Modeling, and Anticipating the Public’s Reaction Presented by: Jennifer Sharp Seinfeld, P.E.
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BACT Issues – A Technical Perspective Presented to: American Public Power Association APPA New Generation Meeting: Anticipating New Permitting Issues, IGCC Technology Options, Atmospheric Modeling, and Anticipating the Public’s Reaction Presented by: Jennifer Sharp Seinfeld, P.E. Principal Zephyr Environmental Corporation June 28, 2006
Outline of Presentation References for developing BACT analysis Overall BACT considerations Pollutant-specific issues/precedents for PC boilers Mercury
Finding Information • The good news… • A lot of useful relevant information is on the web • The bad news… • A lot of useful relevant information is on the web!
Identifying Relevant Projects RBLC Clearinghouse http://cfpub.epa.gov/rblc/cfm/basicsearch.cfm National Coal-fired Utility Projects spreadsheet (updated 10/05) – verify accuracy (http://www.epa.gov/ttncatc1/products.html#misc) DOE Summary of Coal-fired projects (03/06) ( http://www.netl.doe.gov/coal/refshelf/ncp.pdf Clean Air Task Force - New Coal Plant Opposition Draft and Final Permits (http://www.catf.us/projects/power_sector/new_coal_plant_opposition/permits.php) Networking Summaries contained in recently submitted permit applications
References for Emission Limits and BACT Discussions RBLC Clearinghouse Other permits (final, draft proposed) Permit applications, related documents, hearing transcripts, written comments and other correspondence Test/CEMS data from existing units Acid Rain database for historical SO2 emissions http://www.epa.gov/airmarkets/emissions/prelimarp/index.html EPA dockets (http://yosemite.epa.gov/oa/EAB_Web_Docket.nsf/) State and regional databases
Important BACT Considerations Type of unit Fuel type, sulfur content Averaging times, different limits for different averaging times Cost-effectiveness analyses Startup, shutdown, malfunction emissions Method of demonstrating ongoing compliance CEMS Test methods
“Tuning” Periods/Feasibility Studies The ‘middle ground’ in negotiations Pros: Progress toward permit issuance and start of project Flexibility in not having to be in compliance with a challenging limit immediately Cons: Review/regulatory scrutiny continues
SO2 BACT Issues • The basics: • Some type of flue gas desulfurization system (FGD); • SO2 CEMS • For BACT analysis in application, typically expressed in units of lb/MMBtu • Common to have multiple emission limits for different averaging times • Short-term 1 or 3 hrs and/or 24 hrs • Long-term – 30-day and/or annual • Coal washing sometimes raised as an issue • Control efficiency as a permit limit
SO2 BACT Issues – Wet vs. Dry Scrubber • Mix of wet and dry scrubbers in recent permits; majority are dry scrubbers • In general, wet scrubbers are more efficient, but dry scrubbers can still obtain approval • Cost-effectiveness arguments necessary? • Some with tuning periods
BACT Arguments for Dry Scrubbers • Infrastructure • Maintenance considerations • Power and water requirements • Market for wet scrubber byproducts • Generally, higher ground level concentrations with wet scrubber • Better control of sulfuric acid mist, fine particulates, many HAP emissions from wet scrubber (?)
Limits for Dry Scrubbers • Limits for dry are often contested, and have been ratcheted downward • Argument: unrealistic to base SO2 emissions on continuous use of highest sulfur fuel • Use of acid rain data base for typical sulfur content • Examples of recent dry scrubber limits: • City Utilities of Springfield – 0.12 to 0.095 lb/MMBtu (30 day rolling average) • Omaha Public Power Nebraska Cities – 0.10 to 0.095 lb/MMBtu (based on EPA comments) • WI Public Service, Weston 4 – 0.09 lb/MMBtu (12-month average) (based on Sierra Club comments) • Newmont Nevada Energy – 0.09 lb/MMBtu, if fuel S content >0.45%; 0.065 lb/MMBtu, if fuel S content <0.45% S
NOx BACT Issues • The basics: • Controls: SCR + “combustion controls” • CEMS • Averaging time is critical • Quantity of NOx generated depends on type of coal(?) • Ammonia slip • Approx 3 ppm, annual • Higher short-term - ~10 ppm, hourly • Several permits have optimization studies
PM BACT Issues • Basic controls: • Dry FGD: • Baghouse • Wet FGD: • ESP or baghouse for primary filterable PM control • In some cases, wet (or polishing) ESPs downstream of the wet FGD are proposed (e.g., Thoroughbred, Duke Energy, Prairie Generating Station)
PM BACT Issues • Inconsistency in various permit limits • Measurement method really defines particulate matter • Method 5 or 17– all sizes of PM, filterable • Method 201A – PM10, filterable • Method 202 –condensible or “fine PM” • Method 202 may overstate PM10 emissions, due to ammonia and sulfate compounds created in the sampling system
PM BACT Issues • PM/PM10 compliance demonstration • PM CEMS • Performance specifications, PS-11 for PM CEMS • Only measures filterable PM • Typical requirements are periodic tests for PM10 and operational requirements for the PM control device
CO/VOC BACT • Control technology - not an issue, but even these limits keep going down • “Good combustion practices”; trade-off with NOx control • CO CEMS; some permits use CO CEMS as a surrogate to estimate VOC emissions
Mercury • Not subject to Federal PSD-BACT; no more case-by-case analysis • Subject to CAMR (70 FR 28606, revised 71 FR 33388) • CAMR highlights • New coal-fired units – NSPS, Subpart Da • New and existing units – cap and trade • Monitoring requirements • CEMS certified 90 operating days/180 calendar days after operation for new units
Mercury • Some states have more stringent requirements and/or not opt-in to national trading program • Level of detail for application?
Summary • Build a good library of information and continue to update it • Careful review of permit application – it will be scrutinized by many! • Careful negotiations with vendors for emission guarantees • Consider: • SSM emissions • Averaging periods • Method of compliance • Optimization periods
Contact Information Jennifer Sharp Seinfeld, P.E. Zephyr Environmental Corporation 10420 Little Patuxent Parkway, Suite 320 Columbia, Maryland 21044 410-312-7915 jseinfeld@zephyrenv.com visit us at www.ZephyrEnv.com And www.HazMatAcademy