# Presentation: 141238

## Presentation to BOSC

By

U.S. Environmental Protection Agency
Office of Research and Development
National Risk Management Research Laboratory

 February 23, 2005

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

***ORD Mercury Combustion Program:******Status and Accomplishments***

## Overview of Today’s Presentation

- Highlight mercury combustion R&D 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

## 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

## 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)

**Notes:**
EPA has taken regulatory actions to control emissions of Hg from coal-fired utility plants.  The final Hg rule is scheduled to be issued in December of this year (2004).

There is an urgent need to make available cost-effective control technologies in the 2010-2015 timeframe.

Effective mercury control is very coal-type dependent and on the type(s) of air pollution control that are already in place.  There are many opportunities for co-benefit Hg control with existing technologies for control of SOx (wet scrubbers), NOx (selective catalytic reduction, SCR) and particulate matter (PM) control.  Many of our current programs are currently exploring those opportunities.

We are continuing to collaborate with DOE, EPRI, and other organizations in this area.  

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

- Office of Solid Waste (OSW)
- EPA Regional Offices

***Primary Clients***

***Other Clients***

***Collaborators***

- 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

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

***ORD Hg Combustion - Coordination***

## Control TechnologybyRavi Srivastava

## Power Plant Equipment and Mercury

**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**

**Wet Scrubber**

**Hg****0**

**>2500 °F**

**Flue Gas**

**Hg(0), Hg(II), Hg****p ****- form important for capture****1**

**700 °F**

**SCR**

**ESP or FF**

**Coal & Air**

**Ash**

**Residue**

**Ammonia**

**Stack**

**Limestone or lime slurry**

- 1 Hg(0) = elemental Hg; Hg(II) = oxidized Hg; Hgp = particulate Hg

## Sorbent Injection 

**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 SO****3**** and other contaminants**

***Sorbent Injection***

**Sorbent injection + Compact Hybrid Particulate Collector (COHPAC****TM****)**
**Potential solution to ash reuse problems**

**coal**

**Option 2: Electric Power Research Institute’s (EPRI) TOXECONTM System**

**Option1**

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

## Continuation of TOXECONTM DOE Phase I Project Gaston, Low-sulfur Bituminous Coal

**ACI operated nearly continuously between June 26-November  25; rate < 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.**

**Testing Between June-November, 2003**
**(Longest ACI testing period thus far)**

*Source: 2004 Mega Symposium*

## 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 TOXECONTM (using conventional PAC) for Eastern bituminous coal **

## 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 R&D efforts**
- Additive evaluation
- Sorbents for Hg0 absorption

## 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 R&D 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

**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 R&D 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

***Optimization of Existing Controls Projects, cont.***

## Activated Carbon Injection (Project 3)

Key question
How effective are the new class of commercial halogenated carbon sorbents?
Future R&D 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 R&D efforts
Bench-and pilot-scale experiments
Hg chemistry and kinetics for inclusion in predictive models

**Key question**
- How effective are the new class of commercial halogenated carbon sorbents?
**Future R&D 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 R&D efforts**
- Bench-and pilot-scale experiments
- Hg chemistry and kinetics for inclusion in predictive models

***Sorbent Injection Projects***

## Contribution of EPA Science

- Through mercury and multi-pollutant R&D 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

## 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 Agency’s 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

## 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

## Future Activities

**In the future, combustion R&D will:**
- Inform compliance decisions (mercury/multipollutants)
- 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

## Continuous Emissions Monitors for Coal-Fired Power PlantsbyJeff Ryan

## Objectives and Approach

**Quality Hg measurements are critical for:**
**Regulatory application**
**Control technology R&D**
**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**
**Field Demonstrations**

## 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**

## 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**

## 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**

## 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**

## 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?**

## Summary Message

**We’re 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**

## Coal Combustion ResiduesbySusan Thorneloe

## 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)

## 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

## 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)

## 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, OAR’s AA, and the Administrator in 2004.*

## 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

## 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)

## 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.

## 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.

## 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