Presentation to BOSC

1
ORD Mercury Combustion ProgramStatus and
Accomplishments

• Presentation to BOSC
• By
• U.S. Environmental Protection Agency
• Office of Research and Development
• National Risk Management Research Laboratory
• February 23, 2005

2
Overview of Todays Presentation

• Highlight mercury combustion RD included within
  Long Term Goal 1 of the mercury MYP
• To reduce and prevent release of mercury into the
  environment
• Discuss what has been accomplished
• Describe where we need to move in the future

3
ORD Hg Combustion - Background

• Coal combustion is significant source of mercury
  domestically and internationally
• Reducing mercury emissions is complex due to the
  variety of coal types and control technology
  configurations

4
ORD Hg Combustion - Program

• ORD/NRMRL Mercury Combustion Program is
  Addressing
• Approaches to optimize currently utilized SO2,
  NOX, and PM controls to get mercury co-benefit.
• Mercury control via injection of sorbent
  (primarily activated carbon)
• Measurement of mercury emissions from coal-fired
  power plants (e.g., CEMs)
• Potential for re-emission from coal combustion
  residues (fly ash and scrubber sludge)

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ORD Hg Combustion - Coordination
Collaborators
Primary Clients

• Office of Air Radiation (OAQPS and OAP)
• Office of Solid Waste (OSW)
• EPA Regional Offices

• DOE
• EPRI, utilities, others
• Overseas partners
• Energy Research Centre of the Netherlands
• European Union

Other Clients

• Utilities
• States and local regulatory agencies
• DOT and DOI
• Association of State and Territorial Solid Waste
  Management Officials
• Industries using CCR for commercial applications
• Foreign governments

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Control TechnologybyRavi Srivastava
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Power Plant Equipment and Mercury
Hg(0), Hg(II), Hgp - form important for capture1
Wet Scrubber
Stack
SCR
Flue Gas
ESP or FF
Coal Air
700 F
Hg0
Ammonia
gt2500 F
Ash
Residue
Limestone or lime slurry

• Factors that influence mercury control
• Coal type
• Time/temperature profile
• Flue gas composition (chlorine) and fly ash
  characteristics (carbon, calcium, iron, porosity)
• Air pollution controls already in place

1 Hg(0) elemental Hg Hg(II) oxidized Hg Hgp
particulate Hg
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Sorbent Injection
Option1

• Sorbent is injected upstream of the PM control
  device (ESP or FF)
• Collected fly ash and sorbent are mixed

Option 2 Electric Power Research Institutes
(EPRI) TOXECON System

• Sorbent injection Compact Hybrid Particulate
  Collector (COHPACTM)
• Potential solution to ash reuse problems

coal

• The extent of capture depends on
• Sorbent characteristics (particle size
  distribution, porosity, capacity at different
  gas temperatures)
• Residence time in the flue gas
• Type of PM control (FF vs. ESP)
• Concentrations of SO3 and other contaminants

9
Continuation of TOXECONTM DOE Phase I Project
Gaston, Low-sulfur Bituminous Coal
Testing Between June-November, 2003 (Longest ACI
testing period thus far)

• ACI operated nearly continuously between June
  26-November 25 rate lt 0.7 lb/MMacf
• Weekly Hg removal between 80- 90, average 86
• Less variability in emissions over longer
  averaging period
• Need to change air-to-cloth ratio to get 90
  removal
• TOXECON requires a FF after an ESP, a plant
  configuration limited to relatively few plants
  currently.

Source 2004 Mega Symposium
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Performance of Halogenated PACs(B-PAC and E-3)

• Performance of B-PAC and E-3 for Western coal
  (subbituminous, lignite) is similar to that of
  TOXECON (using conventional PAC) for Eastern
  bituminous coal

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Optimization of Existing Controls Projects

• Mercury Control in Wet Scrubbers (Project 1)
• Key question
• Can we increase net capture in wet scrubbers and
  stabilize mercury in scrubber effluent?
• Findings
• Absorbed Hg2 is not stable, a portion of Hg2
  can be reduced to Hg0 and reemitted
• Sulfite/bisulfite and pH identified as reemission
  parameters
• Additives used for waste water treatment may be
  able to stabilize Hg2
• Future RD efforts
• Additive evaluation
• Sorbents for Hg0 absorption

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Optimization of Existing Controls Projects, cont.

• Enhanced Wet Scrubber Hg Control via SCR
  Oxidation (Project 2)
• Key question
• what is the science and can we control the extent
  of oxidation?
• Findings
• HCl is a key source of chlorine needed for Hg0
  oxidation
• No apparent effect of catalyst aging
• Effect of residence time on oxidation
• No apparent effect of SO2 on oxidation
• Future RD efforts
• Fundamental research to identify and characterize
  the role of flue gas composition, fly ash
  properties, and SCR variables on Hg oxidation
• Field tests focusing on SCR impact on Hg
  oxidation for units firing subbituminous coals
  and coal blends

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Sorbent Injection Projects

• Activated Carbon Injection (Project 3)
• Key question
• How effective are the new class of commercial
  halogenated carbon sorbents?
• Future RD efforts
• Burn different rank coals in the Multi-pollutant
  Combustion Research Facility (MPCRF) and assess
  sorbent removal efficiency
• Test effect of carbon feed rate and sorbent type
  on Hg removal
• Evaluate leaching and utilization properties of
  residues
• Develop, evaluate, and characterize the potential
  of advanced sorbents for the removal of mercury
  and other pollutants
• Hg Control with PM Collectors (Project 4)
• Key question
• Can we optimize Hg control with PM collectors
  (ESPs) and thereby greatly reduce the overall
  cost by reducing or eliminating the need for
  activated carbon injection?
• Findings
• Capture of Hg is very dependent upon flue gas
  composition
• Competition between Hg, SO3 and H2O for active
  sorption sites
• Future RD efforts
• Bench-and pilot-scale experiments
• Hg chemistry and kinetics for inclusion in
  predictive models

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Contribution of EPA Science

• Through mercury and multi-pollutant RD efforts,
  ORD has
• Comprehensively assessed state of the art mercury
  mitigation technology
• Characterized key parameters associated with
  SCR-enhanced mercury control
• Identified parameters that impact mercury capture
  in wet scrubbers

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Program Office Support

• ORD has provided key support to OAR during
  development of mercury and multipollutant
  regulations
• Utility Mercury Rule
• Briefed the Administrator on the status of
  mercury controls
• Developed and updated a mercury white paper that
  represents the Agencys technical judgment
  regarding the status of mercury controls, and the
  emission reduction levels potentially achievable
• Developed comprehensive estimates of performance
  and costs of mercury and multipollutant controls
• Clear Skies, Mercury Rulemaking and Interstate
  Air Quality
• Developed estimates of performance and cost of
  mercury, NOX, and SO2 controls for electric
  utility boilers
• Characterized engineering and economic factors
  that affect installations of mercury and
  multipollutant control technologies

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Additional Activities

• Regularly provide guidance on mercury control
  technologies to states, regions, and other
  organizations
• Working with DOE and other interested parties to
  set up an international workshop on mercury
  control in China

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Future Activities

• In the future, combustion RD will
• Inform compliance decisions (mercury/multipollutan
  ts)
• Stimulate development of more cost-effective
  integrated control options
• Assist other countries (e.g., India and China)
  understand how to cost-effectively mitigate their
  mercury emissions - UNEP

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Continuous Emissions Monitors for Coal-Fired
Power PlantsbyJeff Ryan
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Objectives and Approach

• Quality Hg measurements are critical for
• Regulatory application
• Control technology RD
• International emissions inventories
• Hg measurements include
• Manual methods (e.g., OH, M29, etc.)
• Hg CEMs
• Alternative monitors (e.g., sorbent media)
• Hg measurements are complex
• Source variation and characteristics and
  interferences
• Pollution control device effects (inlet/outlet)
• Total vs. speciated Hg
• QA/QC tools (i.e., elemental oxidized Hg gas
  standards)
• Systematic Research and Demonstration
• Fundamental and Laboratory Research
• Pilot-plant testing

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Accomplishments and Impacts

• Regulatory Applications
• Hg monitoring critical component of trading rule
  and Clear Skies
• NRMRL has conducted several Hg CEM pilot-plant
  and field studies that demonstrate current levels
  of performance and support regulatory application
• Demonstrated use of critical elemental and
  oxidized Hg gas standards co-developed by NRMRL
• Written comprehensive status report submitted to
  regulatory docket (FY03 APM)
• Coauthored monitoring procedures in proposed MACT
  and cap and trade rules
• NRMRL generated data to support OAR responses to
  comments

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Accomplishments and Impacts (cont.)

• Control Technology Research Applications
• Reliable Hg CEMs for control technology
  application are critical for technology
  evaluation and process monitoring/control
• Research and technology application are
  complicated by need to perform speciated
  measurements before/after pollution control
  devices
• Numerous biases affect quantification and
  speciation
• Pilot-plant and field proof-of-concept testing of
  device (inertial impactor) to minimize these
  effects have been successful

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Much work still to be done

• Regulatory Application
• Demonstrate proposed/promulgated monitoring
  procedures prior to implementation
• Develop/demonstrate Instrumental Reference Method
  critical for implementation
• Conduct additional field testing to address
  implementation issues
• Demonstrate application in likely post-regulation
  environments through additional field testing
  (PAC inj, SCR, scrubbers, etc)
• Note FY06 APM deliverable on schedule

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Much work still to be done (cont.)

• Control Technology Application
• Must identify, demonstrate and implement accurate
  and reliable process control Hg monitor suitable
  for performance testing
• Additional pilot-plant and field testing critical

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International Application

• Cost-effective monitoring techniques /
  technologies are critical to establishing Asian
  Hg emissions inventory
• Are Hg CEMs practical?
• Costly
• Complex
• Monitoring with sorbent media and continuous
  sampling an option
• Application must be validated (costly)
• Training and Demonstration?

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Summary Message

• Were Not Done Yet
• NRMRL research comprehensively addressing
  regulatory, control technology and international
  activity research needs
• OAR relies heavily on ORD to support regulatory
  issues related to source measurement

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Coal Combustion ResiduesbySusan Thorneloe
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Coal Combustion Residue (CCR) Assessment
Characterization and Cross-Media Transfers

• CCR Work in Support of Long Term Goal 1
• Assess the effect of selected Hg-control
  technologies on the characteristics of CCRs and
  how selected utilization/disposal practices
  impact the fate of Hg and other metals (APM 2003)
• Assess the effect of APC systems on the
  characteristics of Hg-enriched CCRs and increased
  environmental risk from CCR management (APM 2004)
  

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Current Program Outputs

• Completed
• Review of available CCR characterization data and
  management practices (EPA-600/R-02-083, Dec 2002)
  
• Major finding is that available data is of
  limited applicability
• Data are not comparable due to range of leach
  tests in use
• Limited quality assurance or documentation
• Determination of appropriate leach test in
  consultation with OSW
• Major effort to determine appropriate leach
  testing protocol that is applicable to CCR types
  and management practices adopted the Leaching
  Framework (Kosson et al., 2002)
• Meeting with Science Advisory Board in 2003
• supportive of technical approach and high level
  of QA incorporated into protocol

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Current Program Outputs (cont.)

• Completed
• Evaluation of CCRs from 11 Facilities (14 units)
  for total and leachable content for mercury and
  other metals
• A realistic approach was used for long-term metal
  release for a range of conditions typical of CCR
  disposal and utilization (2003-2005) - Draft
  interim report is undergoing review
• Memo for OAR regulatory docket providing results
  from CCR evaluations conducted to date (prepared
  in consultation with OSW)

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Current CCR Characteristics/Results

• Based on four facilities where either ACI or
  brominated sorbents are in use, leaching of
  mercury from CCRs does not appear to be of
  concern for most disposal environments
• Limited data for only two facilities with wet
  scrubbers suggests that leaching of Hg may be of
  concern and warrants further evaluation

Note Briefings providing CCR results were
conducted for OSW, OAQPS, OARs AA, and the
Administrator in 2004.
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Current CCR Characteristics/Results (cont.)

• There are some management practices that may
  aggravate leaching potential (e.g., co-disposal
  with high-sulfur coal rejects).
• Leaching of As and Se is of concern in nearly all
  management scenarios whether or not Hg-control
  is in place
• Advanced sorbent technologies can increase
  capture of Arsenic, selenium, and other metals
  resulting in higher potential environmental
  releases

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In Progress

• Leaching Studies (APM 2006)
• Completing evaluation of CCRs that have been
  received
• Obtaining additional CCRs to account for range of
  expected coal types and air pollution control
  configurations
• Evaluation of potential release rates for use in
  fate and transport models
• Thermal Stability Studies (APM 2008)
• Completing life-cycle evaluation to determine
  environmental tradeoffs from production of wall
  board, asphalt, and cement clinker using CCR and
  non-CCR material
• Examining formation/release of organo-Hg
  compounds for anaerobic decomposition of
  mercury-enriched land-disposed CCRs (APM 2007)
• Capstone report on potential cross-media
  transfers from use of Hg-enriched CCRs in
  commercial applications (APM 2008)

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Current and Future Impacts to Regulatory
Environment

• Will enable EPA to ensure cross-media transfers
  are addressed. Inputs will be used in RCRA
  Subtitle D regulatory effort to evaluate
  potential environmental and health impacts.
• Could result in increased costs for those
  facilities that may have to install engineering
  controls such as use of liners, leachate
  collection, and infiltration control
• Have identified some management practices that
  will aggravate leaching potential.
• Major interest in the U.S. and Europe to utilize
  ash and scrubber sludge. These results can help
  to ensure that scenarios that pose potential
  environmental and health concerns are avoided.
• Results will make it easier to target future
  evaluations of specific CCRs.

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Future Program Outputs

• Current and future in-house CCR research will
• Assist OSW with their health risk assessment and
  development of regulations that respond to
  changing characteristics of coal combustion
  wastes
• Assist with analysis of the fate of Hg and other
  metals from land applied CCRs (APM 2006) Report
  to be produced
• Allow federal/state/local regulators to determine
  beneficial reuse options that are protective of
  human health and the environment (APM 2008)
• Report on formation of organo-Hg from anaerobic
  decomposition of CCRs (APM 2007)
• Report on fate of toxic metals from management of
  CCRs (i.e., disposal and commercial usage) from
  plants equipped with multi-pollutant control
  technologies (APM 2008) will provide mass
  balance tracking fate of mercury and other
  metals.

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Achieved Outcomes

• Critical and comprehensive review of the status
  of mercury controls has significantly enhanced
  the ability of policy makers to make informed
  decisions
• Advanced CEMs for regulatory and control
  technology applications
• Developed/refined protocols to evaluate
  cross-media transfers are now in use allowing
  more informed decisions by stakeholders