Mercury Monitoring and Reporting Requirements under the MATS Rule

1
Mercury Monitoring and Reporting Requirements
under the MATS Rule

• EPRI Conference---Louisville, KY
• May 2012
• Matthew Boze Robert Vollaro
• USEPA, CAMD
• http//www.epa.gov/airmarkets/workshops/index.html
  

2
Background

• On February 16, 2012, EPA published the Mercury
  and Toxics Standards (MATS) rule (40 CFR 63,
  Subpart UUUUU), establishing national emissions
  limitations and work practice standards for
  certain hazardous air pollutants (HAP) emitted
  from coal-fired and oil-fired electric utility
  steam generating units.
• Compliance with the rule is required
• For existing units, by April 16, 2015
• For new or reconstructed units, by April 16,
  2012, or upon startup (first-fire), whichever is
  later
• Compliance must be demonstrated, by means of
  performance testing, no later than 180 days after
  the above dates
• Mercury (Hg) is a regulated HAP under the rule.
• For existing units, the rule specifies both heat
  input-based emission limits (lb/TBtu) and
  electrical output-based limits (lb/GWh) for Hg.

3
Background (contd)

• Compliance with either Hg limit is acceptable for
  existing EGUs.
• For new or reconstructed units, only electrical
  output-based emission limits are specified.
• The magnitude of the applicable Hg emission limit
  depends on which subcategory the EGU is in.
  The general subcategories and applicable Hg
  limits (on a 30-day rolling average basis) are
• Coal-fired units designed to burn coal with GCV
  8,300 Btu/lb
• 1.2 lb/TBtu or 1.3 x 10-2 lb/GWh for existing
  units
• 2.0 x 10-4 lb/GWh for new or reconstructed units
• Coal-fired units designed to burn low-rank virgin
  coal (GCV lt 8,300 Btu/lb)
• 4.0 lb/TBtu or 4.0 x 10-2 lb/GWh for existing
  units
• 4.0 x 10-2 lb/GWh for new or reconstructed units
• IGCC units
• 2.5 lb/TBtu or 3.0 x 10-2 lb/GWh for existing
  units
• 3.0 x 10-3 lb/GWh for new or reconstructed units

4
Background (contd)

• Liquid oil-fired units
• 2.0 x 10-1 lb/TBtu or 2.0 x 10-3 lb/GWh for
  existing units (continental)
• 1.0 x 10-4 lb/GWh for new or reconstructed units
  (continental)
• 4.0 x 10-2 lb/TBtu or 4.0 x 10-4 lb/GWh for
  existing units (non-continental)
• 4.0 x 10-4 lb/GWh for new or reconstructed units
  (non-continental)
• Solid oil-derived fuel (i.e., petroleum
  coke)-fired units
• 2.0 x 10-1 lb/TBtu or 2.0 x 10 -3 lb/GWh for
  existing units
• 2.0 x 10-3 lb/GWh for new or reconstructed units
• Limited-use units in the liquid oil-fired units
  subcategory (lt 8 annual capacity factor, over a
  2-year period) are not subject to emissions
  limits for mercury
• Existing units in the same subcategory at the
  same facility may use emissions averaging for Hg.
  
• If the units in an averaging group are designed
  to burn coal with GCV 8,300 Btu/lb, there are
  alternate Hg limits for the group (1.0 lb/TBtu or
  1.1 x 10-2 lb/GWh on a 90-day rolling average).

5
Hg Compliance Options

• Certain units can comply with the rule by
  qualifying as Low-Emitting EGUs (LEEs). This
  option may not be used for units with main stack
  and bypass stack configurations.
• For Hg, a LEE is a unit that
• Emits at less than 10 of the applicable
  emissions limit or
• Has the potential to emit 29.0 lb of Hg per
  year
• To qualify for LEE status, a demonstration test
  is required.
• EPA Method 30B is used to measure Hg
  concentration for 30 unit operating days
• Paired sorbent traps are used for the test.
• Each pair of traps may be used for up to 10
  operating days
• Additional data (i.e., stack gas flow rate, CO2
  or O2 concentration, moisture, electrical load,
  as applicable) are collected during the test.
  EPA reference methods or certified CEMS that meet
  Part 75 requirements are used to provide the flow
  rate, CO2, O2, or moisture data.
• The additional data are used either to (1)
  convert the measured Hg concentrations to the
  units of the emission limit or (2) enable the
  EGUs potential annual Hg mass emissions to be
  calculated.
• The rule includes special provisions for applying
  the LEE methodology to units that share a common
  stack and units that have multiple stack (or
  duct) exhaust configurations.
• The 30 operating day demonstration test must be
  repeated at least once every 12 months, to show
  that the unit continues to qualify as a LEE for
  Hg.

6
Hg Compliance Options (contd)

• What are the compliance requirements for EGUs
  that do not qualify as LEEs ?
• A liquid oil-fired unit that does not qualify as
  a LEE for total HAP metals (including Hg),
  individual HAP metals (including Hg), or
  filterable PM must demonstrate compliance in
  accordance with 63.10000(c)(2)(ii), either by
• Conducting an initial performance test and
  subsequent quarterly stack tests to show that the
  filterable PM emissions limit is met
• Using a certified PM CEMS to demonstrate initial
  and on-going compliance with the filterable PM
  emission limit or
• Conducting an initial performance test and
  subsequent annual stack tests to show that the
  filterable PM emissions limit is met, and using
  a PM CPMS to monitor continuous performance (with
  respect to an operating limit) in-between the
  annual stack tests.
• A coal-fired unit, IGCC , or solid oil-derived
  fuel (i.e., petroleum coke)-fired unit that does
  not qualify as a LEE for Hg must continuously
  monitor Hg concentration using Hg CEMS or sorbent
  trap monitoring systems, in accordance with
  Appendix A of Subpart UUUUU.

7
Hg CEMS

• Principle
• Representative samples of flue gas are
  continuously extracted from the stack or duct
• Particulate matter is removed (i.e., filtered)
  from the gas samples
• Hg analyzer measures vapor phase Hg0 and Hg2
  (simultaneously or separately)
• Typical Hg CEMS Components
• Probe
• PM filter
• Sample conditioning
• Sample transport (sample line and pump)
• Gas analyzer (with or without converters)
• Calibration gas system

8
Typical Hg CEMS
9
Hg CEMS (contd)

• Types of systems
• Dilution extractive wet basis
• Extractive dry basis
• Development of a quality assurance/quality
  control (QA/QC) program is required.

10
Sorbent Trap Monitoring Systems

• Principle
• Known volumes of flue gas are continuously
  extracted from the stack or duct through paired,
  in-stack sorbent traps. Vapor phase Hg is
  collected on the sorbent medium.
• Typical sorbent medium is halogenated carbon
• Paired sorbent traps are used for
  quality-assurance purposes and to ensure
  measurement precision
• A pair of sorbent traps is typically used for 24
  to 168 hours (but may be used for up to 14
  operating days when the Hg concentration is very
  low), before being removed and analyzed.
• Components
• Dual trains w/sampling probes and paired sorbent
  traps. The sorbent traps have three sections
  (1) main sample collection section (2)
  breakthrough section and (3) section spiked with
  a known mass of Hg0 , for QA/QC .
• Moisture removal system
• Vacuum pump
• Sample gas flow meter

11
Typical Sorbent Trap Monitoring System---PS 12B
12
Sorbent Trap Monitoring Systems (contd)
Probe
3-section sorbent traps
13
Sorbent Trap Monitoring Systems (contd)

• The sorbent trap system must be operated and
  maintained according to Performance Specification
  12B in 40 CFR Part 60, Appendix B.
• Leak checks must be performed (before and after
  sampling)
• Paired sorbent trap consistency/agreement is
  required
• A minimum recovery of the spiked Hg0 in the
  third section is required
• Sample recovery techniques include acid leaching,
  digestion, thermal desorption (see next slide).
• Analytical methods include UV atomic
  fluorescence, UV atomic absorption, and X-ray
  fluorescence
• Analyzer calibration is required
• Development of a QA/QC program is also required.

14
Thermal Desorption System

• Thermal desorption system allows rapid, on-site
  measurement of mercury in sorbent traps
• Alternative to traditional wet chemical analysis
  methods

15
Monitoring System Certification

• Each Hg CEMS or sorbent trap monitoring system
  must be initially certified.
• For Hg CEMS, the following certification tests
  are required
• 7-day calibration error test, using elemental or
  oxidized Hg standards
• Linearity check, using elemental Hg standards
• 3-level system integrity check, using oxidized Hg
  standards
• Cycle time test, using elemental or oxidized Hg
  standards. This test is not required for
  integrated batch sampling-type CEMS
• Relative accuracy test audit (RATA). Note that a
  bias test is not required. Allowable reference
  methods for the RATA include EPA Methods 29, 30A,
  30B, and ASTM D6784-02 (the Ontario Hydro Method)
• All Hg calibration gas standards must be
  traceable to the National Institute of Standards
  and Technology (NIST). EPA , in cooperation with
  industry, NIST, and outside consultants, has
  developed interim traceability protocols. These
  are cited in Subpart UUUUU, Appendix A, sections
  3.1.4 and 3.1.5.

16
Monitoring System Certification (contd)

• For sorbent trap monitoring systems, only a RATA
  is required.
• During the RATA, the monitoring system must be
  operated according to Performance Specification
  12B
• The sorbent material must be the same type that
  is used for daily operation of the system
• The sorbent traps used for the RATA may be
  smaller than those used for daily operation
• The allowable breakthrough in the second section
  of the traps depends on the Hg concentration
  level in the stack gas (see Footnote 1 in Table
  3, below).
• The required tests and performance specifications
  that must be met for initial certification of Hg
  CEMS are summarized in Table 1.
• The RATA specifications for the initial
  certification of a sorbent trap monitoring system
  are the same as those shown in Table 1.

17
Monitoring System Certification(contd)

• Table 1 Certification Requirements for Hg CEMS

For this required certification test..... The main performance specification1 is..... The alternate performance specification1 is..... And the conditions of the alternate specification are.....
7-day calibration error test2 R - A 5.0 of span value, for both the zero and upscale gases, on each of the 7 days R - A 1.0? µg/scm The alternate specification may be used on any day of the test.
Linearity check3 R - Aavg 10.0 of the reference gas concentration at each calibration gas level R - Aavg 0.8 µg/scm The alternate specification may be used at any gas level
3-level system integrity check4 R - Aavg 10.0 of the reference gas concentration at each calibration gas level R - Aavg 0.8 µg/scm The alternate specification may be used at any gas level
RATA 20.0 RA RMavg - Cavg 1.0 µg/scm RMavg lt 5.0 µg/scm
Cycle time test5 15 minutes ----------------------------- ----------------------------
18
On-going Quality-Assurance

• To ensure that certified Hg CEMS and sorbent trap
  monitoring systems continue to provide accurate
  data, the systems are subject to on-going
  quality assurance and quality control (QA/QC)
  requirements.
• For Hg CEMS, the following QA tests are required
• Daily calibration error tests , using elemental
  or oxidized Hg standards
• Weekly single-point system integrity checks ,
  using oxidized Hg standards
• Quarterly linearity checks, using elemental Hg
  standards or 3-level system integrity checks
  using oxidized Hg standards
• Annual RATAs
• For sorbent trap monitoring systems
• The system must be operated and maintained
  according to PS 12B
• Annual RATAs are required
• Quarterly calibration of the gas flow meter and
  auxiliary equipment is required
• The on-going QA/QC requirements and acceptance
  criteria for Hg CEMS and sorbent trap monitoring
  systems are summarized in Tables 2 and 3,
  respectively.

19
On-going Quality Assurance (contd)

• Table 2 On-going QA /QC Requirements for Hg
  CEMS
• 1 Weekly means once every 7 operating days
• 2 NIST-traceable Hg
  standards are required

Perform this type of QA test.... At this frequency.... With these qualifications and exceptions.... Acceptance criteria.
Calibration error test Daily Use either a mid- or high- level gas Use either elemental or oxidized Hg2 Calibrations are not required when the unit is not in operation. R - A 5.0 of span value or R - A 1.0?µg/scm
Single-level system integrity check Weekly1 Use oxidized Hg ---either mid- or high-level Not required if daily calibrations are done with a NIST-traceable source of oxidized Hg R - Aavg 10.0 of the reference gas value or R - Aavg 0.8 µg/scm
20
On-going Quality Assurance (contd)

• Table 2 On-going QA /QC Requirements for Hg
  CEMS (contd)

Perform this QA test.... At this frequency With these qualifications and exceptions.... Acceptance criteria.
Linearity check or 3-level system integrity check Quarterly5 Required in each QA operating quarter3 ---and no less than once every 4 calendar quarters 168 operating hour grace period available Use elemental Hg for linearity check4 Use oxidized Hg for system integrity check4 R - Aavg 10.0 of the reference gas value, at each calibration gas level or R - Aavg 0.8 µg/scm
RATA Annual6 Test deadline may be extended for non-QA operating quarters, up to a maximum of 8 quarters from the quarter of the previous test. 720 operating hour grace period available 20.0 RA or RMavg - Cavg 1.0 µg/scm, if RMavg lt 5.0 µg/scm
21
On-going Quality Assurance (contd)

• Table 3 Normal Operation and QA/QC for Sorbent
  Trap Systems (PS 12B)
• 1 For the RATA, Section 2 breakthrough depends
  on CHg stack gas Hg concentration. Allowable
  breakthrough is 10 of Section 1 mass if CHg is
  gt 1 µg/m3 20 of Section 1 mass if CHg is gt
  0.5 and 1 µg/m3 50 of Section 1 mass if CHg
  is gt 0.1 and 0.5 µg/m3. There is no
  breakthrough criterion if CHg is lt 0.1 µg/m3 .

QA/QC test or specification Acceptance criteria Frequency Consequences if not met
Pre-monitoring leak check 4 of target sampling rate Prior to monitoring Monitoring must not commence until the leak check is passed.
Post-monitoring leak check 4 of average sampling rate After monitoring Invalidate the data from the paired traps or, if certain conditions are met, report adjusted data from a single trap (PS 12B, Section 12.8.1.3).
Ratio of stack gas flow rate to sample flow rate Hourly ratio may not deviate from the reference ratio by more than 25. Every hour throughout monitoring period Invalidate the data from the paired traps or, if certain conditions are met, report adjusted data from a single trap (PS 12B, Section 12.8.1.3).
Sorbent trap section 2 breakthrough 5 of Section 1 Hg mass (for daily operation)1 Every sample Invalidate the data from the paired traps or, if certain conditions are met, report adjusted data from a single trap (PS 12B, Section 12.8.1.3).
22
On-going Quality Assurance (contd)

• Table 3 Normal Operation and QA/QC for Sorbent
  Trap Systems (PS 12B) (contd)

QA/QC test or specification Acceptance criteria Frequency Consequences if not met
Paired sorbent trap agreement 10 Relative Deviation (RD) if the average concentration is gt 1.0 µg/m3 Every sample Either invalidate the data from the paired traps or report the results from the trap with the higher Hg concentration.
Paired sorbent trap agreement 20 RD if the average concentration is 1.0 µg/m3 Every sample Either invalidate the data from the paired traps or report the results from the trap with the higher Hg concentration.
Paired sorbent trap agreement Results also acceptable if difference between paired traps is 0.03 µg/m3 Every sample Either invalidate the data from the paired traps or report the results from the trap with the higher Hg concentration.
Spike Recovery Study Average recovery between 85 and 115 for each of the 3 spike concentration levels Prior to analyzing field samples and prior to use of new sorbent media Field samples must not be analyzed until the percent recovery criteria has been met.
Multipoint analyzer calibration Each analyzer reading within 10 of true value and r2 0.99 On the day of analysis, before analyzing any samples Recalibrate until successful
Analysis of independent calibration standard. Within 10 of true value Following daily calibration, prior to analyzing field samples Recalibrate and repeat independent standard analysis until successful.
Spike recovery from section 3 of both sorbent traps 75125 of spike amount Every sample Invalidate the data from the paired traps or, if certain conditions are met, report adjusted data from a single trap (PS 12B, Section 12.8.1.3).
23
On-going Quality Assurance (contd)

• Table 3 Normal Operation and QA/QC for Sorbent
  Trap Systems (PS 12B) (contd)
• 2 Annually means once every four QA operating
  quarters. Limited extensions of the RATA
  deadline are allowed for non-QA quarters---the
  maximum allowable extension is 8 calendar
  quarters from the previous RATA. A 720
  operating hour grace period is available.

QA/QC test or specification Acceptance criteria Frequency Consequences if not met
Relative Accuracy RA 20.0 of RM mean value or if RM mean value 5.0 µg/scm, absolute difference between RM and sorbent trap monitoring system mean values 1.0 µg/scm RA specification must be met for initial certification and annually2 thereafter Data from the system are invalid until a RATA is passed.
Gas flow meter calibration An initial calibration factor (Y) has been determined at 3 settings for mass flow meters, initial calibration with stack gas has been performed. For subsequent calibrations, Y within 5 of average value from the most recent 3-point calibration At 3 settings prior to initial use and at least quarterly at one setting thereafter Recalibrate meter at 3 settings to determine a new value of Y.
Temperature sensor calibration Absolute temperature measured by sensor within 1.5 of a reference sensor Prior to initial use and at least quarterly thereafter Recalibrate sensor may not be used until specification is met.
Barometer calibration Absolute pressure measured by instrument within 10 mm Hg of reading with a NIST-traceable barometer Prior to initial use and at least quarterly thereafter Recalibrate instrument may not be used until specification is met.
24
Hg Emissions Reporting

• For units that qualify as LEEs for Hg, the
  results of all 30-day demonstration tests must be
  submitted to EPAs WebFIRE database, using the
  Electronic Reporting Tool (ERT). The results
  must be submitted within 60 days after completing
  each test.
• For units that continuously monitor Hg emissions
• A monitoring plan must be developed and
  maintained.
• The Hg CEMS or sorbent trap monitoring system(s)
  and any required additional monitoring systems
  must be represented in the monitoring plan.
• Monitoring plan data must be submitted to EPA
  electronically and updated when necessary, using
  the Emissions Collection and Monitoring Plan
  System (ECMPS) Client Tool.
• Hourly Hg concentration data must be reported
  electronically using the ECMPS Client Tool.
• Data from Hg CEMS are reduced to hourly averages
• For sorbent trap monitoring systems, the Hg
  concentration obtained from the analysis of a
  pair of traps is reported for each hour of the
  data collection period.

25
Hg Emissions Reporting (contd)

• Quarterly electronic reporting of Hg emissions is
  required, no later than 30 days after the end of
  each calendar quarter.
• Hourly records of any additional data needed to
  convert Hg concentration to units of the emission
  standard (e.g., stack gas flow rate and/or
  moisture content, CO2 or O2 concentration,
  electrical load) must be included in the
  electronic quarterly reports.
• The additional monitoring system(s) used to
  convert Hg concentration to units of the standard
  must meet the requirements of 40 CFR Part 75.
• For sorbent trap monitoring systems, certain
  other hourly data must be reported (i.e., sample
  flow rate, gas flow meter reading, and the ratio
  of stack gas flow rate to sample flow rate).
• The data acquisition and handling system (DAHS)
  must be programmed to provide an hourly data
  stream in the units of the applicable Hg emission
  standard (lb/TBtu or lb/GWh).
• Hg emission rates are calculated only for
  operating hours in which valid data are obtained
  for all parameters in the applicable equation(s).
  For the purposes of Subpart UUUUU, Part 75
  substitute data are not considered to be valid
  data.

26
Hg Emissions Reporting (contd)

• Operating hours in which a valid Hg emission rate
  is not obtained are counted as hours of
  monitoring system downtime.
• Only unadjusted monitoring data are used to
  calculate Hg emission rates. Bias adjustment
  factors (BAFs) are not applied to any of the
  parameters.
• The results of all required certification and QA
  tests of Hg CEMS, sorbent trap monitoring
  systems, and the additional monitoring system(s)
  used to convert Hg concentration to units of the
  standard must be reported electronically, using
  the ECMPS Client Tool.
• For Hg CEMS and sorbent trap monitoring systems,
  RATA results and test details must also be
  submitted to the WebFIRE database via ERT, within
  60 days after completing each test.
• Compliance with the 30 (or in some cases, 90)
  operating day rolling average Hg emission rates
  is assessed in the semiannual reports required
  under 63.10031.

27
Future Changes to ECMPS for Hg

• EPA is reviewing the Hg reporting schema and
  reporting instructions (March 5, 2008) drafted
  for CAMR. This will be our starting point for
  integrating continuous Hg data into ECMPS.
• Structurally, that schema is compatible with the
  MATS Hg continuous monitoring and reporting
  requirements
• New method of determination codes (MODC) will be
  needed to handle the differences between the
  CAMR rule and the MATS rule.
• Exclusion of Startup and Shutdown hours
• Handling of invalid data hours No Substitute
  Data
• No Bias Adjustments
• Etc.

28
Future Changes to ECMPS for Hg CEMS

• Monitoring Plan will have to reactivate the
  ltCalibrationStandardgt record for reporting the
  basis of daily calibrations (i.e., Hg0 or Hg2 )
• Add 3-level System Integrity Check to the QA
  schema
• Add the ltWeeklySystemIntegrityDatagt record back
  to the Emissions schema. Program to check for
  this on an operating day basis when Hg0 is used
  in daily calibrations.
• Hourly Hg concentration measurements to be
  recorded in MHV records
• Hourly Hg emission rate data to be reported in
  DHV records

29
Future Changes to ECMPS for Hg Sorbent Trap
Monitoring Systems

• Add the QA record structure for reporting the
  required Gas Flow Meter Calibrations, GFM
  temperature sensor barometer calibration checks
• Create special emissions data schema to support
  sorbent trap monitoring
• Hourly GFM Data record
• Sampling Train Data record
• Sample Train Data would contain all the
  information necessary to determine the quality
  assurance status of each sampling period.
• Spike Recovery
• Breakthrough
• Trap Agreement
• Stack Flow to Sample Rate Ratio Check
• Leak Check

30
Future Changes to ECMPS for Hg Sorbent Trap
Monitoring Systems (continued)

• Concentration determined from a sampling period
  would be entered into the appropriate hourly MHV
  records
• This allows the data to be used to determine
  hourly emission rates and treated like Hg CEMS
  data for compliance averaging.
• Also allows for a sorbent trap systems to be used
  as a backup to Hg CEMS, (if desired to keep data
  loss at a minimum).
• Hourly Hg emission rate data to be reported in
  DHV records

31
ECMPS Process Forward

• EPA is committed to ensuring that the continuous
  monitoring data for MATS is integrated into ECMPS
  in a manner that is consistent with the process
  currently used for Part 75 reporting.
• Also, we will be working on more specific draft
  documents on the specific plans as they relate to
  MATS ECMPS monitoring requirements
• Reporting Schema
• Reporting Instructions
• Check Specifications
• Stakeholder meetings
• Goal is to have ECMPS and your DAHS programming
  updated, tested and ready to go by 1Q2015