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MERCURY REGULATIONS AND MEASUREMENT IN FLUE GASES

MERCURY REGULATIONS AND MEASUREMENT IN FLUE GASES. February 2016. Summary of Advances in CEM-Based Mercury flue gas measurements, Stimulated by - US EPA Emission Regulations & QA/QC - Challenges of measuring H g in flue gas - Performance evaluations at low H g Levels - Technical Advances.

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MERCURY REGULATIONS AND MEASUREMENT IN FLUE GASES

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  1. MERCURY REGULATIONS AND MEASUREMENT IN FLUE GASES February 2016

  2. Summary of Advances in CEM-Based Mercury flue gas measurements, Stimulated by - US EPA Emission Regulations & QA/QC - Challenges of measuring Hg in flue gas - Performance evaluations at low Hg Levels - Technical Advances

  3. U.S. EPA EGU MATS and Cement MACT • Summary – for EGUs, mercury concentration must be really low at ~ 170 parts per trillion (v/v) = 1.5 µg/m3for EGUs

  4. U.S. EPA EGU MATS and Cement MACTSummary – [Hg] must be really low ~ 1.5 ug/m3 for EGUs • EPA Electric Generating Unit Mercury and Air Toxic Standards (MATS) promulgated January 2012 • Targeted MATS Pollutants and limits Deadline for Compliance – April, 2015 • The EPA Portland Cement MACT • Targeted MACT Pollutants and limits Deadline for Compliance – September, 2015

  5. Typical US Power Plant Mercury % Reduction to Meet Regulations

  6. Impact of US EPA Regulations • New Air Pollution Control Strategies • New or Improved Monitoring Technologies • Proof of Performance of 1 & 2 • Compliance Monitoring and Reporting • Control Systems Performance Monitoring and Optimization • Plant Closures

  7. In the USA, HgCEM Equipment Trials in Real Flue Gas Determines Acceptance • Because U.S EPA Regulations are based on performance standards, there is no need to have an equivalent MCERTS or TUV certification required in the USA for HgCEM equipment. Instead there are: • EPA Field Trials in 2004-2005 • Independent Research Group Performance Testing • Field Trials by Power and Cement Companies • Frequent Relative Accuracy Tests (RATA)

  8. U.S. EPA Trials 2005 - Summary • Relative Accuracy must be <20% • Most HgCEMs did poorly, except Tekran and Thermo. Only the Tekran 3300 CEM was able to pass allUSEPA Trial performance measurements.

  9. RTP Campus, North Carolina US EPA - Research Triangle Park • After 2005 Trials - US EPA purchased three (3) Tekran Series 3300 CEM systems • EPA Team responsible for conducting North Carolina and Kentucky long-term trials • Evaluated all competitive CEM offerings prior to selecting Tekran • Chosen after observing Series 3300 in service for almost one year • Selected due to advanced automation capabilities • Will be used for Hg control technology research, among other applications

  10. Field Trials: Lessons Learned about HgCEM System Design and Operation • The coal flue gas matrix is very challenging • Conversion of Hg2+to Hg0 quantitatively with long-term robustness is critical for success • Quantitative transport of Hg species from probe to detector requires: • Dilution with dry air • High temperatures for Hg2+ - no cold spots • Inert surface materials

  11. MATRIX: Accurately Measuring pptv* Levels of Mercury in Coal Flue Gas SO2 • 1 µg/m3 Hg = 112 parts per trillion (v/v) • Accurate measurements requires understanding and managing the many potential mercury redox reactions with halogens, sulfur oxides and water in the gas phase and on surfaces • Tekran R&D spent 1998 to 2003 understanding flue gas mercury reactions in the laboratory • Detectors can only measure Hg0 HBr NOX H2O Hg0 Fe HCl HgCl2 Se Hg0

  12. CONVERSION: The Challenge of Mercury and Reactive Halogens • Hg0 + reactive halogen is our friend and foe: • Required for Hg analysis by HgCEMs and direct thermal method for sorbent traps (30B) • Helpful for Hg control and used for HgCEM performance checks • Bi-directional reaction affected by • Temperature • Catalytic surface reactions • Gas and particle matrix Bi-directional reactions For analysis, Hg0 formation must be quantitative with no back reaction For control, HgX2formation and capture needs to be quantitative with no back reaction to minimize release of Hg0 Simplified chemistry for illustration purposes only HgCl2 Hg0+ Cl2 Hg0+Br2 HgBr2

  13. Tekran 3300Xi HgCEM Flue Gas Converter/Conditioner (patented) • Task: quantitatively convert all Hg2+ to Hg0 with no back reactions in a complex flue gas matrix • Proprietary thermal converter material set at 700 degrees C • DI water injected into tail of thermal converter to “fix” Hg0 from potential back reactions and eliminate interferences • Gas is rapidly chilled, water condenses and removes reactive compounds. Only Hg0 remains in clean gas matrix for analyzer

  14. TRANSPORT: HgCEM design to minimize transport reactions and losses • 30:1 dilution with dry zero air (can be higher) • Filter element and related surfaces made with inert coatings and frequent system blowbacks (hourly) • For umbilical lines, must use fluoropolymer tubing (PFA, FEP), heated to 180˚ C, with no cold spots • Thermal converter catalyst material is robust and surface chemistry has been characterized and is known • Inject fresh DI water after the thermal converter and rapidly drop the temperature, to chemically “fix” Hg0 and prevent Hg(II) re-formation by back reactions with reactive halogens or other compounds (Tekran only) • In effect, a mini wet-scrubber with chilled coalescing filter

  15. EERC Study Low-Level Measurements (funded by EPRI, ICCI, CATM in 2010)

  16. Joint EERC, EPRI & ICCI ProjectDetermining the Accuracy of CMMs at Low Mercury ConcentrationsFigures adapted from Laudal et al., 2010 NOTE: The coal result bias for the Thermo Freedom System was resolved on a second test at EERC

  17. Reliant Energy: HgCEM Accuracy - low Hg levels – wet scrubber stack - 2007 • Sorbent Traps (avg) = 0.59 ug/m3 • Tekran with M&C (avg) = 0.56 ug/m3 • Slide courtesy of Eric Roland NOTE: Reliant Energy is now NRG

  18. Relative Accuracy TestingEPA Method 30B • This method is only intended for use only under relatively low particulate conditions (e.g., sampling after all pollution control devices) • This method is designed to measure the mass concentration of total vapor phase Hg in flue gas, including elemental Hg (Hg0) and oxidized forms of Hg (Hg2+), in micrograms per dry standard cubic meters (µg/dscm) • Sorbent Traps have: • mineral wool section (intended for PM), • primary capture section, • secondary (breakthrough) capture section • final mineral wool section • Particulate Hg that is captured in the trap is included in the analysis

  19. Tekran HgCEM RATA Results

  20. Tekran 3300Xi HgCEM SystemSame trusted components with improved physical design 3300Xi HgCEM * wall mounted * 2537Xi Analyzer 3310Xi Hg0 Calibrator • 3321 • Conditioner • Controller • Oxidizer Option

  21. 2537Xi Analyzer • 100% backwards compatibility with prior 2537 units • Network enabled • High resolution touch screen interface • Local data storage and front panel USB port retrieval and update • Improved accessibility of routine maintenance components

  22. Tekran 2537Xi • On-board storage of sample data with front panel USB retrieval • Connectable via RS232, RS485, network port, or USB port • Data logging of multiple instrument parameters • Built-in data review screens • Remote instrument login and control • Digital controls of all devices (PMT, Perm Source, Lamp, etc.) • RS-485 allows communication with external devices Data Handling & Communication

  23. Flow Diagram of Tekran Model 2537X Automated Mercury Analyzer (Pat’d)

  24. Tekran 3310Xi Elemental Calibrator Key Features • NIST owns two units as NIST-Prime Generators • NIST Traceable • Wide range of 0-1900 ug/m3 and up to 30 lpm • Mercury source is precisely heated or cooled to ± 0.05 °C and lasts for many years • High accuracy mass flow controllers (MFC) with upstream pressure regulators and temperature control

  25. Tekran 3310Xi Elemental Mercury Calibration Source (simplified schematic)

  26. Tekran New Generation HgCEM System3321 Sample Conditioner and Control Unit Converter Conditioner Components • Modular Power Panel • Modular Umbilical Heaters • Probe Control Hardware • Modular Electronics HgCl2 Generator • Oxidizer Type • Optional Wall-mounted - cabinet closed

  27. Tekran Oxidizer for generating HgCl2 gas for converter efficiency QA test

  28. Tekran 3300Xi System Diagram 1304Xi Zero Air Panel 3342 Probe 3321 Conditioner, Probe Controller, Oxidized Hg supply (optional) Note: heated lines can connect to top or side of 3321. Small Rack w/ 2537Xi, 3310Xi & PC System Control 1308 Recirculating Water Supply

  29. Cabinet-Based Tekran 3300Xi HgCEMS Interior 3300Xi HgCEMS Cabinet Cabinet for HgCEMS

  30. Tekran 1308 Re-Circulating DI Water Supply Tekran 3321 CCU The Tekran Model 1308 minimizes maintenance Tekran 1308 water is supplied from collection reservoir in closed loop cycle

  31. 1304Xi Zero Air System

  32. Tekran CEM+ Controller Software • Graphical User Interface with HMI • Streamlined configuration process • Modular Design • Easy to add reporting modules if reporting formats change • Easy to add modules for data analysis • Ease of Deployment • One-click installation

  33. Tekran 3300Xi Dual Port Sampling Applications: • Mercury control technology • Research and development • Acceptance testing at new installations • Optimization and performance monitoring • Regulatory monitoring of multiple, close-proximity emissions stacks.

  34. Conclusions • In 2015, very low USA Hg emission regulations will be enforced for coal (MATS) and cement plants (PC MACT). • Only a few HgCEM vendors have the ability to comply with the required QA and traceability protocols • A sensitive, accurate and robust HgCEM design must deal with the challenges of the flue gas matrix, Hg2+to Hg0conversion and efficient transport • The Tekran 3300Xi HgCEM is the only instrument capable of measuring accurately below 1.0 ug/m3. • Custom Tekran HgCEM Systems are being used to develop, study and commercialize mercury control technology.

  35. Mercury Control Research, Equipment and example Results

  36. Tekran 3300RS (Research Systems) 3300RS-Dual Probe 3300RS Upstream Injection

  37. Schematic of Johnson Matthey Catalyst Testing Equipment Simulated Power Plant Exhaust gas Heated Reactor with catalyst FTIR analysis Tekran 3300RS Dual Port system SO3 analysis Slide courtesy of Michael Nash at Johnson Matthey Reactor Outlet

  38. Johnson Matthey 3300RS Dual Port System and Test Rig Configuration Slide courtesy of Michael Nash at Johnson Matthey

  39. Example data from Johnson MattheyConversion of Hg0 to Hg2+ across a catalyst Online measurement of flue gas components during simulated power plant conditions. Condition 1: a low halogen bituminous condition Condition 2: a high halogen bituminous condition Slide courtesy of Michael Nash at Johnson Matthey

  40. Mercury Research Configuration at Shanghai Jiaotong University Reactor and sorbent performance evaluation with controlled Hg source and Tekran 3300RS Unit Slide courtesy of Professor Yan NaiQiang at Shanghai Jiaotong University

  41. Example Mercury Research Results fromShanghai Jiaotong University • Conversion of Hg0 to Hg2+ • Good mass balance • Good recovery to zero Hg – no memory effect Slide courtesy of Professor Yan NaiQiang at Shanghai Jiaotong University

  42. U. of Ningbo-Nottingham Hg Control Technology Configuration with 3300-RS Slide courtesy of Dr. Tao Wu’s Research Lab at the U. of Ningbo-Nottingham

  43. Cormetech Micro-Reactor Schematic • Mainly used for parametric studies of both fresh and deactivated catalyst • The reactor is a fully automated and continuous system capable of injecting a wide variety of gaseous and aqueous species • Capable of measuring DeNOx, SO2 oxidation, and Hg0oxidation over a single layer Slide courtesy of Cormetech

  44. Cormetech Reactor & Tekran 3300RS Unit • This Tekran 3300RS was designed to provide known upstream input of Hg0 and Hg2+ using a custom injection module • Installed in a vented enclosure Slide courtesy of Cormetech

  45. Cormetech Example of an Hg0 Trend for a Continuous Hg Test • Reactor is fully automated, using pre-defined testing sequence and stability criteria • Automated allows many factors to be tested • Factors affecting Hg0 oxidation are temperature, AV, and Hg0, NH3, SO2, CO, HCl, and HBr concentrations Slide courtesy of Cormetech

  46. Mercury Emission Research Conclusions • The Tekran 3300RS provides a custom platform for sensitive and robust mercury control technology research and development • The Tekran 3300RS is being used to evaluate sorbent injection, catalyst oxidation, fixed-bed filters, wet-scrubbers and additives to control mercury emissions • Emission research and control programs are using Tekran equipment at universities and commercial companies in China, Poland, UK, Korea and the USA

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