August 2001
Environmental Technology
Verification Report
Nippon Instruments Corporation
Model AM-2 Elemental Mercury
Continuous Emission Monitor
Prepared by
Baltelle
Putting Technology To Work
Battel le
Under a cooperative agreement with
£EPA U.S. Environmental Protection Agency
ETV EjV ElV
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I lll ENVIRONMENTAL TECHNOLOGY VERIFICATION
PROGRAM J
SERA ETV
U.S. Environmental Protection Agency SS 2?
^•llr Dopnr imone
11 ENVIRONMENTAL
DdllClIC P R O T E C T . O *
.. . Putting Technology To Work
ETV Joint Verification Statement
TECHNOLOGY TYPE: Continuous Emission Monitor
APPLICATION:
MEASURING ELEMENTAL MERCURY
TECHNOLOGY
NAME:
Model AM-2
COMPANY:
Nippon Instruments Corporation
ADDRESS:
WEB SITE:
E-MAIL:
14-8 Akaoji-cho, Takatuki-shi PHONE: +81-726-94-5195
Osaka 569-1146 Japan FAX: +81-726-94-0663
http://www.smglink.com/nic
nic@rigaku.co.j p
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology Verification (ETV)
Program to facilitate the deployment of innovative or improved environmental technologies through performance
verification and dissemination of information. The goal of the ETV Program is to further environmental protec-
tion by substantially accelerating the acceptance and use of improved and cost-effective technologies. ETV seeks
to achieve this goal by providing high-quality, peer-reviewed data on technology performance to those involved
in the design, distribution, financing, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; with stakeholder groups that
consist of buyers, vendor organizations, and permitters; and with the full participation of individual technology
developers. The program evaluates the performance of innovative technologies by developing test plans that are
responsive to the needs of stakeholders, conducting field or laboratory tests (as appropriate), collecting and
analyzing data, and preparing peer-reviewed reports. All evaluations are conducted in accordance with rigorous
quality assurance protocols to ensure that data of known and adequate quality are generated and that the results
are defensible.
The Advanced Monitoring Systems (AMS) Center, one of six technology centers under ETV, is operated by
Battelle in cooperation with EPA's National Exposure Research Laboratory. The AMS Center has recently
evaluated the performance of continuous emission monitors used to measure mercury in flue gases. This
verification statement provides a summary of the test results for the Nippon Instruments Corporation Model
AM-2 elemental mercury continuous emission monitor (CEM).
5
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VERIFICATION TEST DESCRIPTION
The verification test was conducted over a three-week period in January 2001 at the Rotary Kiln Incinerator
Simulator (RKIS) facility at EPA's Environmental Research Center, in Research Triangle Park, North Carolina.
This mercury CEM verification test was conducted jointly by Battelle's AMS Center, EPA's Office of Research
and Development, and the Massachusetts Department of Environmental Protection. A week of setup and trial runs
was followed by two weeks of verification testing under different flue gas conditions. The daily test activities
provided data for verification of the following performance parameters of the AM-2 monitor: relative accuracy in
comparison to reference method results, correlation with the reference method, precision in sampling at stable
flue gas conditions, calibration/zero drift from day to day, sampling system bias in transfer of mercury to the
CEM's analyzer, interference effects of flue gas constituents on CEM response, response time to rising and
falling mercury levels, response to low levels of mercury, data completeness over the course of the test, and setup
and maintenance needs of the CEM. The Ontario Hydro (OH) draft American Society for Testing and Materials
mercury speciation method was used as the reference method in this verification test. Paired OH trains were
sampled at two locations in the RKIS duct to establish the precision of the OH method.
Quality assurance (QA) oversight of verification testing was provided by Battelle and EPA. Battelle QA staff
conducted a data quality audit of 10% of the test data, a series of performance evaluation audits on several
measurements at the RKIS, and both an internal and an external technical systems audit of the procedures used in
this verification. EPA QA staff also conducted an independent technical systems audit at the RKIS.
TECHNOLOGY DESCRIPTION
The AM-2 mercury CEM is a sampling, preconcentration, and detection system for elemental mercury. The unit
draws a sample flow rate of 0.5 L/min through a distilled water scrubbing trap, for removal of any oxidized
mercury species, and then through a dehumidifier, for removal of water vapor. The sample flow then passes
through a gold amalgamation trap, which collects and concentrates the elemental mercury from the sample
stream. Rapid heating of the gold trap drives the collected mercury into the absorption cell of the detector of the
AM-2. Operating the unit with a fixed sample flow rate, collection time, and detection conditions allows the AM-
2 response to be related to the (ig/m3 of mercury in the original sample stream. The sampling, desorption, and
detection steps are conducted in a fully automated sequential fashion, so the AM-2 provides one measurement of
elemental mercury with each complete cycle. In this verification test, the AM-2 operated with a 5-minute sample
collection step, and a 13-minute overall cycle time. The AM-2 uses cold vapor atomic absorption to detect
elemental mercury. The AM-2 requires no chemical reagents or gases other than a purified air supply, and
operates on 100-110 V AC power. The unit is 44.5 cm wide x 28.7 cm deep x 28.5 cm high (17.5 in. W x 11.3 in.
D x 11.2 in H), and weighs 20 kg (44 lbs). A front panel keyboard allows programming of the AM-2 cycle param-
eters, and an LCD display provides a readout for mercury concentrations, date, time, self diagnostic functions,
and error messages. A thermal dot matrix printer and RS-232C port for output of measurement data are built into
the AM-2.
VERIFICATION OF PERFORMANCE
Relative accuracy: During the first week of verification testing, the Nippon AM-2 provided relative accuracy for
elemental mercury of about 14% relative to OH results, at elemental mercury levels of approximately 6 to
7 (ig/m3. In the second week of verification, the AM-2 provided relative accuracy of about 23%, with elemental
mercury levels ranging from about 5 to 25 (ig/m3. Excluding two of the nine OH runs in the second week, the
AM-2 gave a relative accuracy of 12.3% in the second week of verification.
Correlation with the reference method: The coefficient of determination (r2) of the AM-2 and OH results was
0.878, based on the combined data from both weeks of verification.
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Precision at stable flue gas conditions: The precision (as percent relative standard deviation) of the AM-2
response was within 10% in 11 of the 15 OH periods and within 15% in 13 of the periods. This measured
variability includes both variability in the test facility and in the AM-2 monitor.
Calibration/zero drift: Analysis of elemental mercury standard gases gave a 4.1% relative standard deviation
(RSD) in AM-2 response during the first week of testing and a 3.4% RSD in AM-2 response during the second
week.
Sampling system bias: The bias in transport of elemental mercury through the Nippon inlet system was
approximately -7%.
Interference effects of flue gas constituents: When added to the duct along with mercury, chlorine (and to a
lesser extent hydrogen chloride) sharply reduced the elemental mercury response of the AM-2. However, elevated
levels of sulfur dioxide, nitrogen oxides, and carbon monoxide had a minimal effect on AM-2 response, and when
these gases were all present along with chlorine and hydrogen chloride, no reduction in AM-2 response was
observed, relative to that with mercury alone.
Response time to changing mercury levels: The AM-2 achieved 90 to 100% response to increases and
decreases in mercury concentrations within one 13-minute measurement cycle. Thus, the 95% response time is
essentially one measurement cycle.
Response to low levels of mercury: The AM-2 elemental mercury response increased with as little as
0.57 |ag/m3 of total mercury added to the flue gas. The actual elemental mercury concentrations were not
determined independently for comparison to the AM-2 results. However, the AM-2 elemental mercury readings
were highly correlated with the nominal total mercury level (r2 = 0.997).
Data completeness: Data completeness for the AM-2 was 100%.
Setup and maintenance needs: The AM-2 was set up and ready to sample flue gas within about four hours after
it was placed at the sampling port. The monitor required no gas supplies or other consumables and produced no
waste. No scheduled maintenance was required over the two-week period of the verification test.
Gabor J. Kovacs Date Gary J. Foley Date
Vice President Director
Environmental Sector National Exposure Research Laboratory
Battelle Office of Research and Development
U.S. Environmental Protection Agency
Gina McCarthy Date
Assistant Secretary for Pollution Prevention,
Environmental Business and Technology
Massachusetts Executive Office of Environmental Affairs
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NOTICE: ETV verifications are based on an evaluation of technology performance under specific,
predetermined criteria and the appropriate quality assurance procedures. EPA and Battelle make no expressed or
implied warranties as to the performance of the technology and do not certify that a technology will always
operate as verified. The end user is solely responsible for complying with any and all applicable federal, state,
and local requirements. Mention of commercial product names does not imply endorsement.
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August 2001
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
Nippon Instruments Corporation
Model AM-2 Elemental
Mercury Continuous Emission Monitor
by
Thomas Kelly
Charles Lawrie
Karen Riggs
Battelle
Columbus, Ohio 43201
Jeffrey Ryan
Office of Research and Development
U.S. Environmental Protection Agency
Research Triangle Park, North Carolina 27711
with support from
Massachusetts Department of Environmental Protection
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Notice
The U.S. Environmental Protection Agency (EPA), through its Office of Research and
Development, has financially supported and collaborated in the extramural program described
here. This document has been peer reviewed by the Agency and recommended for public release.
Mention of trade names or commercial products does not constitute endorsement or
recommendation by the EPA for use.
ii
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Foreword
The U.S. EPA is charged by Congress with protecting the nation's air, water, and land resources.
Under a mandate of national environmental laws, the Agency strives to formulate and implement
actions leading to a compatible balance between human activities and the ability of natural
systems to support and nurture life. To meet this mandate, the EPA's Office of Research and
Development provides data and science support that can be used to solve environmental
problems and to build the scientific knowledge base needed to manage our ecological resources
wisely, to understand how pollutants affect our health, and to prevent or reduce environmental
risks.
The Environmental Technology Verification (ETV) Program has been established by the EPA to
verify the performance characteristics of innovative environmental technology across all media
and to report this objective information to permitters, buyers, and users of the technology, thus
substantially accelerating the entrance of new environmental technologies into the marketplace.
Verification organizations oversee and report verification activities based on testing and quality
assurance protocols developed with input from major stakeholders and customer groups
associated with the technology area. ETV consists of six technology centers. Information about
each of these centers can be found on the Internet at http://www.epa.gov/etv/.
Effective verifications of monitoring technologies are needed to assess environmental quality and
to supply cost and performance data to select the most appropriate technology for that assess-
ment. In 1997, through a competitive cooperative agreement, Battelle was awarded EPA funding
and support to plan, coordinate, and conduct such verification tests for "Advanced Monitoring
Systems for Air, Water, and Soil" and report the results to the community at large. Information
concerning this specific environmental technology area can be found on the Internet at
http://www.epa.gov/etv/07/07_main.htm.
iii
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Acknowledgments
The authors wish to acknowledge the support of all those who helped plan and conduct the
verification test, analyze the data, and prepare this report. In particular we would like to thank
Bea Weaver, Adam Abbgy, and Paul Webb of Battelle. We thank those staff of EPA's
Environmental Research Center who provided assistance in the field tests. We also acknowledge
the support of Chris Winterrowd and other staff of ARCADIS Geraghty & Miller for their work
in operating the test facility, conducting Ontario Hydro sampling, and reporting data for this
report. The participation of Koji Tanida and Munehiro Hoshino of Nippon Instruments
Corporation is gratefully acknowledged.
iv
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Contents
Notice ii
Foreword iii
Acknowledgments iv
List of Abbreviations ix
1. Background 1
2. Technology Description 2
3. Test Design and Procedures 4
3.1 Introduction 4
3.2 Test Conditions 6
3.2.1 RKIS Conditions 6
3.2.2 AM-2 Operation 8
3.2.3 Ontario Hydro Reference Method 11
3.3 Verification Procedures 12
3.3.1 Relative Accuracy 12
3.3.2 Correlation with Reference Method 13
3.3.3 Precision 13
3.3.4 Calibration/Zero Drift 14
3.3.5 Sampling System Bias 14
3.3.6 Interferences 15
3.3.7 Response Time 15
3.3.8 Low-Level Response 16
3.3.9 Data Completeness 16
3.3.10 Setup and Maintenance Needs 16
3.4 Equipment and Materials 17
3.4.1 Commercial Elemental Mercury Standards 17
3.4.2 Performance Evaluation Equipment 18
v
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4. Data Quality 20
4.1 Facility Calibrations 21
4.2 Ontario Hydro Sampling and Analysis 21
4.2.1 Ontario Hydro Precision 22
4.2.2 Ontario Hydro Blank Trains 27
4.2.3 Ontario Hydro Reagent Blanks 27
4.3 Mercury Mass Balance 28
4.4 Audits 29
4.4.1 Technical Systems Audit 29
4.4.2 Performance Evaluation Audits 29
4.4.3 Data Quality Audit 32
5. Statistical Methods 33
5.1 Relative Accuracy 33
5.2 Correlation with Reference Method 33
5.3 Precision 34
5.4 Calibration/Zero Drift 34
5.5 Sampling System Bias 34
5.6 Interferences 35
5.7 Response Time 35
5.8 Low-Level Response 35
6. Test Results 36
6.1 Relative Accuracy 36
6.2 Correlation 38
6.3 Precision 38
6.4 Calibration/Zero Drift 39
6.5 Sampling System Bias 40
6.6 Interference Effects 41
6.7 Response Time 43
6.8 Low-Level Response 43
6.9 Data Completeness 45
6.10 Setup and Maintenance 45
6.11 Cost 45
7. Performance Summary 46
8. References 48
vi
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Figures
Figure 2-1. Nippon Instruments Corporation Model AM-2 Mercury Continuous
Emission Monitor 2
Figure 3-1. Side View (top) and End View (bottom) of RKIS Test Facility 9
Figure 6-1. Correlation Plot of AM-2 and OH Results for Each Week of Testing 38
Figure 6-2. Nippon AM-2 Response in Interference Test, January 18, 2001 42
Figure 6-3. Nippon AM-2 Elemental Mercury Response in Low-Level
Sensitivity Test, January 19, 2001 45
Tables
Table 3-1. General Schedule of the ETV Mercury CEM Verification Test 5
Table 3-2. Schedule of Daily Activities in the Mercury CEM Verification Test 7
Table 3-3. Summary of RKIS CEMs 10
Table 3-4. Target of Flue Gas Constituent Concentrations Used
in Verification Test 10
Table 3-5. Schedule of OH Sampling Runs During Mercury CEM Verification 13
Table 3-6. Schedule of January 18, 2001, Interference Test 15
Table 3-7. Schedule of January 19, 2001, Low-Level Response Test 16
Table 3-8. Mercury Standard Gas Identification and Analysis Results 18
Table 3-9. Performance Evaluation Audit Equipment Used for the Verification Test 19
Table 4-la. Elemental Mercury Results from OH Sampling in the First Week of
Verification Testing 23
Table 4-lb. Oxidized Mercury Results from OH Sampling in the First Week of
Verification Testing 23
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Table 4-lc. Total Mercury Results from OH Sampling in the First Week of
Verification Testing 24
Table 4-2a. Elemental Mercury Results from OH Sampling in the Second Week of
Verification Testing 24
Table 4-2b. Oxidized Mercury Results from OH Sampling in the Second Week of
Verification Testing 25
Table 4-2c. Total Mercury Results from OH Sampling in the Second Week of
Verification Testing 25
Table 4-3. Equivalent Flue Gas Mercury Concentrations (//g/m3) Found in Blank
Ontario Hydro Trains 27
Table 4-4. Percent Recovery of Total Mercury Injected into the RKIS 28
Table 4-5. Summary of PE Audits on Mercury CEM Verifications 30
Table 4-6. Results of PE Audit of OH Train Analysis 31
Table 6-1. Average Elemental Mercury Results from Nippon AM-2
CEM During OH Sampling Runs 37
Table 6-2. Relative Accuracy Results for the Nippon AM-2 37
Table 6-3. Precision Results for the Nippon AM-2 40
Table 6-4. Zero and Standard Gas Responses of the Nippon AM-2 41
Table 6-5. Summary of Calibration/Zero Drift Results for the Nippon AM-2 41
Table 6-6. Data from Response Time Tests on the Nippon AM-2 44
Table 6-7. Results of Response Time Tests: Percentage Response to
Concentration Change Within One AM-2 Cycle 44
viii
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List of Abbreviations
AMS
Advanced Monitoring Systems
ANOVA
analysis of variance
APCS
air pollution control system
CEM
continuous emission monitor
Cl2
chlorine
CO
carbon monoxide
co2
carbon dioxide
EPA
U.S. Environmental Protection Agency
ETV
Environmental Technology Verification
GFCIR
gas filter correlation infrared
h202
hydrogen peroxide
h2so4
sulfuric acid
HC1
hydrogen chloride
Hg
mercury
Hg°
elemental mercury
HgCl2
mercuric chloride
KC1
potassium chloride
KMn04
potassium permanganate
L/min
liters per minute
m3
cubic meters
MDEP
Massachusetts Department of Environmental Protection
mg/m3
milligrams per cubic meter
mL
milliliter
NDIR
non-dispersive infrared
NIST
National Institute of Standards
NO
nitric oxide
N0X
nitrogen oxides
o2
oxygen
OD
outside diameter
OH
Ontario Hydro
ORD
Office of Research and Development
PE
performance evaluation
PPb
parts per billion
ppm
parts per million
Psig
pounds per square inch gauge
QA
quality assurance
QC
quality control
QMP
Quality Management Plan
ix
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RA
relative accuracy
RKIS
Rotary Kiln Incinerator Simulator
RSD
relative standard deviation
so2
sulfur dioxide
TSA
technical systems audit
X
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Chapter 1
Background
The U.S. Environmental Protection Agency (EPA) has created the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative environmental tech-
nologies through performance verification and dissemination of information. The goal of the
ETV Program is to further environmental protection by substantially accelerating the acceptance
and use of improved and cost-effective technologies. ETV seeks to achieve this goal by provid-
ing high-quality, peer-reviewed data on technology performance to those involved in the design,
distribution, permitting, purchase, and use of environmental technologies.
ETV works in partnership with recognized standards and testing organizations; with stakeholder
groups that consist of buyers, vendor organizations, and permitters; and with the full participation
of individual technology developers. The program evaluates the performance of innovative tech-
nologies by developing test plans that are responsive to the needs of stakeholders, conducting
field or laboratory tests (as appropriate), collecting and analyzing data, and preparing peer-
reviewed reports. All evaluations are conducted in accordance with rigorous quality assurance
protocols to ensure that data of known and adequate quality are generated and that the results are
defensible.
The EPA's National Exposure Research Laboratory and its verification organization partner,
Battelle, operate the Advanced Monitoring Systems (AMS) Center under ETV. The AMS Center
recently evaluated the performance of continuous emission monitors (CEMs) for mercury
emissions in combustion flue gas. This verification report presents the procedures and results of
the verification test for the Nippon Instruments Corporation Model AM-2 elemental mercury
CEM.
1
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Chapter 2
Technology Description
The objective of the ETV AMS Center is to verify the performance characteristics of environ-
mental monitoring technologies for air, water, and soil. This verification report provides results
for the verification testing of the Nippon Instruments Corporation Model AM-2 mercury CEM.
The following description of the AM-2 is based on information provided by the vendor.
The AM-2 mercury CEM is a sampling, preconcentration, and detection system for elemental
mercury. The unit draws a sample flow rate of 0.5 L/min through a distilled water scrubbing trap,
for removal of any oxidized mercury species, and then through a dehumidifier, for removal of
water vapor. The sample flow then passes through a gold amalgamation trap, which collects and
concentrates the elemental mercury from the sample stream. Rapid heating of the gold trap drives
the collected mercury into the absorption cell of the detector of the AM-2. Operating the unit
with a fixed sample flow rate, collection time, and detection conditions allows the AM-2
response to be related to the (ig/m3 of mercury in the original sample stream. The sampling,
desorption, and detection steps are conducted in a fully automated sequential fashion, so the
AM-2 provides one measurement of elemental mercury with each complete cycle. In this veri-
fication test, the AM-2 operated with a 5-minute sample collection step, and a 13-minute overall
cycle time.
I
J
\
\
Figure 2-1. Nippon Instruments Corporation
Model AM-2 Mercury Continuous Emission
Monitor
The AM-2 uses cold vapor atomic absorption
to detect elemental mercury. The detection
limit of the AM-2 for environmental monitor-
ing is 0.1 ng/m3 or less. As modified for flue
gas analysis in this verification test, the AM-2
had a detection limit of about 0.1 (ig/m3 for
emission monitoring. The AM-2 requires no
chemical reagents or gases other than a
purified air supply, and operates on 100-110 V
AC power. The unit is 44.5 cm wide x 28.7 cm
deep x 28.5 cm high (17.5 in. W x 11.3 in. D x
11.2 in H), and weighs 20 kg (44 lbs). A front
panel keyboard allows programming of the
AM-2 cycle parameters, and an LCD display
provides a readout for mercury concentrations,
date, time, self diagnostic functions, and error
2
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messages. A thermal dot matrix printer and RS-232C port for output of measurement data are
built into the AM-2.
3
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Chapter 3
Test Design and Procedures
3.1 Introduction
This verification test was conducted according to procedures specified in the Test/QA Plan for
Pilot-Scale Verification of Continuous Emission Monitors for Mercury.(1) The Nippon
Instruments Model AM-2 CEM was verified for its measurement of elemental mercury by
comparison to reference method measurements, by challenges with interferant species, and by
repeated sampling of elemental mercury standard gases. The test activities provided data for
verification of the following performance parameters of the AM-2 monitor:
¦ Relative accuracy in comparison to reference method results
¦ Correlation with the reference method
¦ Precision in sampling at stable flue gas conditions
¦ Calibration/zero drift from day to day
¦ Sampling system bias in transfer of mercury to the CEM's analyzer
¦ Interference effects of flue gas constituents on CEM response
¦ Response time to rising and falling mercury levels
¦ Response to low levels of mercury
¦ Data completeness over the course of the test
¦ Setup and maintenance needs of the CEM.
All but the last parameter listed were evaluated quantitatively, using data produced by the
planned sequence of tests. The data used to verify these parameters are specified later in this
section, and the statistical calculations used to quantify these parameters are presented in
Section 5 of this report. The last parameter listed, setup and maintenance needs, was evaluated
qualitatively by observing the operation and maintenance of the CEM by vendor staff during the
test.
The verification test was conducted over a three-week period in January 2001 at the Rotary Kiln
Incinerator Simulator (RKIS) facility at EPA's Environmental Research Center, in Research
Triangle Park, North Carolina. The RKIS is a gas-fired, two-stage, pilot-scale incinerator that
allows flue gas composition to be manipulated by injecting pollutant gases, particulate matter,
and mercury at various points within and downstream of the combustion zone. The RKIS flue
gases pass through an extended length of duct before entering an air pollution control system
(APCS). When mercury is introduced into the facility flue gas, the facility must operate as a
permitted hazardous waste facility, with limitations on hours of operation and personnel training.
4
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In particular, mercury injection into the RKIS flue gas could be performed only between the
hours of 6:00 AM and 6:00 PM.
This mercury CEM verification test was conducted jointly by Battelle's AMS Center, EPA's
Office of Research and Development (ORD), and the Massachusetts Department of Environ-
mental Protection (MDEP). Specifically, ORD research programs on mercury chemistry and
emissions made major contributions to this verification test in the form of planning and
organization, facility operations, data acquisition, and leadership in conducting the tests at the
RKIS. The MDEP provided financial support and comments on the test plan for this verification.
In addition to these collaborations, important contributions to the study were made by the staff of
ARCADIS Geraghty & Miller, Inc. Under subcontract with EPA/ORD, ARCADIS staff operated
the test facility and associated monitoring equipment and conducted ancillary tasks, such as
sampling, to confirm the concentrations of commercially prepared elemental mercury gas
standards. Under subcontract with Battelle, ARCADIS staff performed reference flue gas
mercury sampling, coordinated the analysis of those samples, and provided the resulting data for
this report.
The schedule for the mercury CEM verification followed that stated in the test/QA plan,(1) in that
a week of setup and trial runs was followed by two weeks of verification testing under different
flue gas conditions. The overall schedule of the test is shown in Table 3-1.
Table 3-1. General Schedule of the ETV Mercury CEM Verification Test
Date Verification Test Activities
January 8-12, 2001 Installation of vendor CEMs; shakedown of facility operations and
mercury injection procedures; trial sampling of flue gas
January 15-19, 2001 Verification testing with flue gas composition approximating that of a
coal-fired power plant
January 22-25, 2001 Verification testing with flue gas composition approximating that of a
municipal waste incinerator
January 26, 2001 Packing of vendor CEMs; end of test
The first and second weeks of verification testing (January 15 to 19 and 22 to 25, respectively)
were similar, in that largely the same daily sequence of tests was conducted in each of these
weeks. However, as noted in Table 3-1, the flue gas composition differed between the two
weeks.
It should be pointed out that, although facility shakedowns and trial sampling of flue gas were
conducted during the week of January 8 to 12, relatively little time was available for the mercury
CEMs to sample the full flue gas matrix. The variety of startup activities made it impossible to
conduct full days of trial flue gas sampling. This situation contrasts with the normal installation
procedures for such CEMs, in which one or two days are often allotted for extensive sampling of
5
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the facility flue gas to tailor the CEM operation for the facility. The verification results reported
here must be considered in light of this mode of operation.
The daily schedule of the verification test is illustrated in Table 3-2, which shows the testing
activities conducted on each day and the CEM performance parameters addressed by each
activity. The exact times when specific test procedures were done are noted when appropriate
elsewhere in this report. On each day of the week, the AM-2 was challenged with a zero gas and
a commercial compressed gas standard of elemental mercury. These gases were supplied to the
analyzer one at a time as a test of day-to-day stability and speed of response. This test was done
twice a day, except that on the last day of each week it was done only once. Monday through
Wednesday of each week, the flue gas was sampled simultaneously by the AM-2 and the Ontario
Hydro(2) reference method. On Thursday and Friday of the first week, interference and low-level
mercury response tests were done, respectively.
Throughout the verification test, the AM-2 was operated by representatives of Nippon
Instruments Corporation. The intent of the testing was for the AM-2 to operate in a manner
simulating operation at a combustion facility. Therefore, once the verification test began, no
recalibration was performed other than the AM-2's built-in automated zeroing procedure. Nippon
staff prepared reagents, maintained the monitor's inlet system, and handled recovery of data from
the AM-2.
3.2 Test Conditions
The AM-2 was one of four mercury CEMs tested in this verification effort. All verification
testing took place simultaneously, so that all CEMs were subjected to exactly the same test
conditions.
3.2.1 RKIS Conditions
The natural gas combustor of the RKIS was operated continuously throughout the test period, to
maintain elevated duct temperatures and thereby minimize the chance of retention and subse-
quent release of mercury by the refractory or other components of the system. The flue gas from
the natural gas combustor was spiked with gases, mercury, and particulate matter to achieve
different representative flue gas compositions. In all cases, once the required injection rates of
mercury, gases, and particulate matter were established, at least 30 minutes of stabilization time
was allowed before the start of any reference method sampling or verification data collection.
Mercury was injected into the RKIS flue gas using a peristaltic pump and aqueous solutions of
mercury(II) or chloride (HgCl2). Different injection locations and injection solutions were tried in
trial runs to achieve stable total mercury levels and a reasonable split between elemental and
oxidized mercury in the duct. The final selection was to use mercury(II) chloride solutions, with
different injection locations (i.e., different injection temperatures) to achieve different
elemental/oxidized splits in the two weeks of testing.
6
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Table 3-2. Schedule of Daily Activities in the Mercury CEM Verification Test
Test Day AM/PM Activity (Performance Parameters)
Monday 1/15/01 AM Zero/Hg° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Flue gas sampling (Relative Accuracy, Correlation, Precision)
PM Zero/Hg° standard gas (Calibration/Zero Drift, Response Time)
Tuesday 1/16/01 AM Zero/Hg° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Flue gas sampling (Relative Accuracy, Correlation, Precision)
PM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time)
Wednesday 1/17/01 AM Zero/Fig ° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Flue gas sampling (Relative Accuracy, Correlation, Precision)
PM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time)
Thursday 1/18/01 AM Zero/Fig ° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Spiking of flue gas with interferant gases (Interferences)
PM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time)
Friday 1/19/01 AM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time,
Sampling System Bias)
AM/PM Preparation of low Fig levels in flue gas (Fow-Fevel Response)
Monday 1/22/01 AM Zero/Fig ° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Flue gas sampling (Relative Accuracy, Correlation, Precision)
PM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time)
Tuesday 1/23/01 AM Zero/Fig ° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Flue gas sampling (Relative Accuracy, Correlation, Precision)
PM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time)
Wednesday 1/24/01 AM Zero/Fig ° standard gas (Calibration/Zero Drift, Response Time)
AM/PM Flue gas sampling (Relative Accuracy, Correlation, Precision)
PM Zero/Fig0 standard gas (Calibration/Zero Drift, Response Time)
Thursday 1/25/01 AM/PM Repeat of some interference tests (Interferences)
PM Zero/Hg° standard gas (Calibration/Zero Drift, Response Time,
Sampling System Bias)
7
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Potential interferant gases (sulfur dioxide, nitrogen oxides, carbon monoxide, hydrogen chloride,
chlorine) were injected into the RKIS duct downstream of the combustion zone, using cylinders
of the pure compressed gases as the source. Nitrogen oxides in the flue gas were prepared by
injection of nitric oxide (NO). The target gas levels were established by monitoring the concen-
tration in the duct using the RKIS facility CEMs (see Table 3-3), rather than by estimation based
on dilution in the duct flow. The only exception was for chlorine, for which no CEM was avail-
able. The chlorine concentration was established by first injecting chlorine into the flame zone of
the RKIS, where complete conversion of chlorine to hydrogen chloride is thermodynamically
assured, and measuring the resulting hydrogen chloride using the hydrogen chloride CEM. The
chlorine injection rate was then maintained, but moved to a lower temperature injection point and
the concentration of HC1 was measured again. The chlorine concentration was established from
the difference in the two HC1 readings.
Particulate matter was injected into the duct at the downstream end of the RKIS combustion
zone, using a K-Tron Soder Model KCLKT20 screw feeder, which incorporated a strain gauge
measurement of the mass of material injected. The fly ash used was a lignite coal fly ash,
specially chosen for its low reactivity with mercury. The low target particulate loading
(30 mg/m3) required operating the feeder at the extreme low end of its operating range, and
resulted in substantial variation in the particulate loading in the duct (see below).
Figure 3-1 shows two views of the RKIS test facility and indicates the locations of the injection
points for particulate matter, mercury, and interferant gases. Also shown are the port locations
RM1 (Port 2) and RM2 (Port 8) where the reference Ontario Hydro (OH) method samples were
collected. That sampling is presented in detail in Section 3.2.3. Between these two locations, at
Ports 6 and 7, were the sampling locations of the mercury CEMs undergoing testing; the AM-2
was located at Port 7. The AM-2 test setup is described in more detail in Section 3.2.2.
Figure 3-1 also shows the sampling location for the facility CEMs, downstream of all the
sampling locations. The CEMs in place at the RKIS for this test are shown in Table 3-3.
The test conditions maintained throughout OH sampling in the two weeks of verification testing
were intended to represent a coal-fired power plant flue gas and an incinerator flue gas, respec-
tively. Table 3-4 summarizes the target and actual levels of mercury and of the other constituents
in the flue gas in the two weeks of testing. In general, the actual constituent levels in the flue gas
were close to the target levels. The mercury present during the first week of testing was pre-
dominantly in elemental form. During the second week of testing, to challenge the speciation
capabilities of the CEMs, the injected mercury was predominantly in oxidized form. The flue gas
water and oxygen contents were very consistent throughout both weeks of testing, at about 7%
water and 14.6% oxygen, and the flue gas temperature at the CEM sampling ports was 400 to
430°F .
3.2.2 AM-2 Operation
The AM-2 was installed on a table within about three feet of the duct, at the port location
identified as Port 7 in Figure 3-1. The AM-2 shared a sample probe and particle filter with
another Nippon Instruments mercury CEM. The probe consisted of a glass tube of about 8-mm
outside diameter (OD) enclosed in a stainless steel tube that extended to near the center of the
8
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Gale
Valve interference
s Inj.
Port 1
TC4
Port 2
TC5
RM1
I Gas Inj. I
I I i
I KorIJ Port 4
I i
©
H *
e
$
(p ~
0
d
0
0
o
o
Secondary Combustion Chamber
Duct 1
TC
t m-
u-
T--
Legend
Flyash
Injection
~ 4" Port
0 3" Port
a
~
Mercury
injection
/ / \ \
/ ' \ \
_
U 11
KSn Section Transition Section
_G round Floor
Ul
Port 5 —~iO
tb
Draft Damper
CEM
Hd, S02, H20
i J
FGCS Manifold
o
4" Port
0
3" Port
0
2" Port
Thermocouple
Port 8
RM2
Figure 3-1. Side View (top) and End View (bottom) of the RKIS Test
Facility
9
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Table 3-3. Summary of RKIS CEMs
Analyte
CEM
Principle
Measurement
Range (s)
o2
Rosemount Analytical Model 755R
Paramagnetic
0 - 25%
co2
Fuji Electric ZRH-1 Gas Analyzer
NDIR
0 - 20%
CO
Horiba Model PIR 2000
NDIR
0 - 500 ppm
NO/NOx
Thermo Environmental Model 10
Chemiluminescent 0 - 500 ppm
S02
Bodenzeewerk Model MCS 100
GFCIR
0 - 250, 0 - 2,500 ppm
HC1
Bodenzeewerk Model MCS 100
GFCIR
0- 100,0 - 1,000 ppm
Table 3-4. Target Flue Gas Constituent Concentrations (and Actual Ranges) Used in
Verification Test
Total Hg S02
Test Week (pg/m3) (ppm)
NOx
(ppm)
HC1 Particles
(ppm) (mg/m3)
One
8a 1,000
(7.3 - 7.8) (952 - 978)
250
(226 - 245)
25 30
(21.5-24.3) (0.2-71)
Two
80b 50
(72 - 119) (51 - 63)
150
(137 - 159)
100 30
(77 - 92) (2 - 54)
a Predominantly elemental Hg.
b Predominantly oxidized Hg.
duct. The probe connected to a heated glass container holding a glass fiber thimble filter. Each of
the two Nippon Instruments CEMs drew sample gas through identical heated 6-mm OD Teflon
lines, connected to a glass "T" fitting at the outlet of the filter housing. The sample gas flow of
the AM-2 was 0.5 L/min. The total gas flow through the inlet probe and filter was about 1 L/min,
and sampling was not isokinetic.
The nature of the inlet system is an important factor in verifying the performance of a mercury
CEM, because the materials and temperature of the inlet may affect the chemical speciation and
even the quantity of mercury that reaches the CEM. Since the CEMs were verified in this test
partly by comparison to the OH method, each vendor was informed of the characteristics of the
inlet system used with the OH trains. Vendors then made their own decisions about how best to
sample the flue gas to assure consistent comparisons with the OH method. In the inlet system
used with the AM-2, the filter was maintained at about 400°F, similar to the duct temperature;
the heated line from the filter holder to the AM-2 was maintained at about 300°F. At the
vendor's discretion, due to the low particulate matter loading, the inlet filter was changed only
after the first week of testing. The AM-2 determines vapor-phase elemental mercury only, so the
particulate matter collected on the filter was not analyzed.
10
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The AM-2 is a batch-wise, rather than truly continuous, mercury monitor. That is, the AM-2
automatically cycled through a sequence of sample collection, analysis, and zeroing that took
about 13 minutes. Included in that sequence was a five-minute sampling interval. Thus the AM-2
provided a reading of elemental mercury in the flue gas every 13 minutes, based on a five-minute
sample period. The output of the AM-2 was recorded both on a laptop computer and on the
monitor's built-in printer.
3.2.3 Ontario Hydro Reference Method
The OH mercury speciation method® was used as the reference method in this verification test,
because of the need for a recognized approach to verify the elemental and oxidized mercury
measurements made by the CEMs. Since the OH method is not officially designated as a
reference method by EPA or the American Society for Testing and Materials, it was judged
necessary to document the precision of the OH method itself during the verification test. As a
result, in each OH sampling run, two OH trains were operated simultaneously at each of the two
reference sampling points at the RKIS (Port 2, or RM1, and Port 8, or RM2 in Figure 3-1). At
each location, two trains were placed at ports on opposite sides of the duct (designated 2A, 2C,
8A, and 8C, respectively), with their inlet probes positioned close together near the center of the
duct. Thus, four OH trains were used for sampling at the same time in each OH run. Each OH
train used a separate inlet probe and heated filter and sampled isokinetically near the duct center-
line. An EPA Method 2 traverse was conducted at each OH sampling location, both before and
after each OH run, to set the isokinetic sampling rate. The average of pre-and post-run traverses
was used for final calculations.
The particulate filters in the OH trains were maintained at 250°F. No heating was applied to the
sample probe, instead the sample temperature dropped naturally from the duct temperature to the
filter temperature in passage from the probe to the filter. A sampling flow of about 1 m3/hr (about
16.7 L/min) was used in all OH runs.
None of the CEMs undergoing verification determined particulate mercury. As a result, the
particulate filters from the OH trains were used for two purposes: to determine particulate
mercury and to determine the particulate mass loading in the duct. For each OH run, one of the
particulate filters from each sampling location (RM1 and RM2, Figure 3-1) was used for gravi-
metric determination of particle mass loading. The other was analyzed for particulate phase
mercury. This approach provided a check on the particulate mercury level, while avoiding the
expense of additional Method 5 runs to determine the particle loading. As detailed in
Section 4.2.1, the particulate mercury determined by the OH sampling was negligible.
The meter boxes of the paired OH trains at each location were located side by side to allow
monitoring by a single operator during sampling. During the runs, OH train data were recorded
by hand on data sheets prepared for this test and also were entered immediately into an Excel
spreadsheet running on a laptop computer at the sampling location. That spreadsheet auto-
matically calculated run parameters, such as percent of isokinetic sampling rate, providing rapid
and accurate control of the sampling process.
11
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The OH trains were prepared by ARCADIS staff in a dedicated laboratory close to the RKIS high
bay. Trains were brought to the RKIS for sampling and returned to the same laboratory for
sample recovery immediately after sampling. Blank trains (one per day of OH sampling) were
also brought to one of the sampling locations at the RKIS and returned along with the sampled
trains for sample recovery. The glassware set used for the blank train was chosen at random each
day from the several sets on hand. In addition, blank samples were taken of all reagents and rinse
solutions used in the OH method. Samples were recovered into uniquely identified pre-labeled
glass containers according to OH method procedures. Samples were delivered by ARCADIS staff
within about 24 hours after sampling to Oxford Laboratories, in Wilmington, North Carolina, for
analysis. Staff of Oxford Laboratories verified sample identities from chain-of-custody sheets
before beginning sample analysis.
OH sampling was conducted under conditions of stable flue gas composition, on Monday,
Tuesday, and Wednesday of each test week (i.e., on January 15 to 17 and 22 to 24, 2001). Two
OH runs per day, of two hours each, were made during the first week. Three OH runs per day, of
one hour each, were made during the second week. Typical sampled gas volumes were about
2 cubic meters and 1 cubic meter in the first and second weeks of testing, respectively. Table 3-5
shows the actual schedule of OH sampling in the verification test. The OH sampling proceeded
smoothly, with the single exception of Run 9, which was interrupted by failure of the mercury
solution injection pump. That run was resumed after repair of the pump, and no data were lost.
3.3 Verification Procedures
This section describes the specific procedures used to verify the CEM performance parameters
that were listed in Section 3.1. The statistical procedures used to calculate the verification results
are described in Section 5 of this report.
3.3.1 Relative Accuracy
Relative accuracy was assessed by the quantitative comparison of the mercury results from the
OH method to those from the tested CEM. For the AM-2, this comparison was made only for
elemental mercury. The AM-2 results during the period of each OH run were averaged for
comparison to the OH result. In making this comparison, it must be noted that the cycle time of
the AM-2 was 13 minutes, during which time gas was sampled for only five minutes. Thus, no
more than five AM-2 data points were obtained for each hour of OH sampling, and the coverage
of the sampling period by the AM-2 was 5/13 = 38%. This difference in sampling coverage was
not important when flue gas mercury levels were constant, as in most OH runs. However, in a
few cases, spikes in the indicated mercury level were observed simultaneously on more than one
of the participating CEMs as a result of inadvertent brief changes in flue gas composition. The
impact of such a spike on the AM-2 result could be different from the impact on the correspond-
ing OH result. Consequently, the data were reviewed for the impact of such spikes on the
accuracy calculation.
12
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Table 3-5. Schedule of OH Sampling Runs During Mercury CEM Verification
Week
Run
Number
Date
Start Time
End Time
One
1
1/15/01
12:07
14:08
2
1/15/01
15:36
17:37
3
1/16/01
12:12
14:13
4
1/16/01
15:45
17:45
5
1/17/01
10:58
12:59
6
1/17/01
14:21
16:22
Two
7
1/22/01
11:32
12:33
8
1/22/01
13:25
14:25
9
1/22/01
16:15
16:5 la
17:40
18:07a
10
1/23/01
10:47
11:47
11
1/23/01
12:50
13:51
12
1/23/01
16:00
17:01
13
1/24/01
11:15
12:15
14
1/24/01
14:30
15:31
15
1/24/01
16:15
17:16
a Run 9 was interrupted by a failure of the peristaltic pump used to inject mercury solution into the RKIS; the run
was resumed after fixing the pump and allowing concentrations to stabilize.
The accuracy was calculated separately for the two different test conditions, i.e., the 24 OH
results from the first week of testing and the 36 OH results from the second week were the basis
for separate calculations of accuracy.
3.3.2 Correlation with Reference Method
The correlation of the AM-2 with the OH results was assessed using the same data used to assess
accuracy. The average AM-2 elemental mercury results over each OH sampling run were
calculated and compared to the corresponding OH results.
3.3.3 Precision
Precision of the AM-2 was determined based on the individual AM-2 results in each OH
sampling run. The relative standard deviation of the successive AM-2 readings was calculated as
13
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the measure of precision. This calculation was intended to assess CEM variability under con-
ditions of stable mercury levels. Consequently, this calculation was limited to those time periods
in which CEM data, facility data, and the observations of testing staff indicated that mercury
addition and mercury flue gas levels were stable. Occasional spikes in mercury concentration
were excluded from the calculation of precision, provided that the spikes were attributable to
occurrences at the test facility, either by corroboration of multiple CEMs, or by observations of
testing staff.
3.3.4 Calibration/Zero Drift
Day-to-day drift in AM-2 response to calibration and zero gases was assessed by sampling zero
gas (nitrogen) and a commercial standard of elemental mercury in nitrogen with the monitor each
day. The standard gases used for this procedure are described in Section 3.4.1. Those gases were
not used as absolute mercury standards, but only as sources of stable mercury levels over the test
period. The calibration/zero check was done twice on each day of testing, before and after all
other test activities. However, on the last day of each week, this test was done once and was com
bined with a check of the sampling system bias (see Section 3.3.5). A low concentration mercury
standard (-15 (ig/m3) was used in the first week, and a higher concentration standard
(~ 50 (ig/m3) was used in the second week, to parallel the flue gas mercury levels used (see
Table 3-4).
Drift was assessed in terms of the range and relative standard deviation of the repeated zero and
calibration checks. Separate assessments of drift were made for the two weeks of testing.
3.3.5 Sampling System Bias
In nearly all cases, the drift checks described in Section 3.3.4 were conducted by supplying the
zero and standard gases directly at the analyzer inlet of the CEM. However, on the last day of
each week of testing, a drift check conducted in that manner was followed immediately by a
similar check in which each gas was supplied at the inlet of the CEM's flue gas sampling system.
The ratio of the CEM response at the analyzer to that through the entire sampling system
determined the bias caused by the sampling system.
The AM-2 shared an inlet system with another Nippon Instruments CEM, as described in Section
3.2.2. That other CEM provided continuous real-time data, in contrast to the 13-minute cycle
time of the AM-2. The two CEMs were connected to the inlet system in identical configurations.
As a result, to facilitate the bias test procedure, the response of the other CEM was used to assess
the sampling system bias.
The sampling system bias test was performed by withdrawing the Nippon sampling probe from
the duct and connecting the tip of the inner glass probe to a Teflon line supplying the zero or
calibration gas. A "T" fitting in the line allowed venting of a small excess flow of gas beyond
that drawn by the Nippon CEMs. The gas supplied in this way passed through the probe, filter,
and heated sampling lines before entering the analyzer inlets of the CEMs.
14
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3.3.6 Interferences
On Thursday, January 18, the same low mercury level used on previous days (see Table 3-4) was
established in the RKIS flue gas. The addition of mercury alone continued for approximately two
hours, during which time the AM-2 sampled the flue gas to establish a baseline level of response.
Then, with the mercury injection continuing as before, a series of potential interferant gases was
injected into the flue gas, first one at a time, and then in combination. Finally, the gases were
turned off, and the mercury injection alone was continued for about another half hour. The effect
of the interferant gases was assessed by the changes in AM-2 response occurring during the intro-
duction of the gases.
Table 3-6 summarizes the schedule of the interference test on January 18. Shown are the
substances injected into the RKIS flue gas in successive time intervals during this test. The
concentrations shown in Table 3-6 are the target concentrations; actual concentrations were
maintained within ± 10% of the target values.
Table 3-6. Schedule of January 18, 2001, Interference Test
Time
Substances Injected in Flue Gas (Target Concentration, ppm)
Hga
(pg/m3)
NO CO S02 HC1 Cl2
11:05 - 13:06
8
13:06-13:39
8
500
13:39-14:16
8
500
14:16-15:05
8
2,000
15:05 - 15:50
8
250
15:50-16:30
8
10
16:30-17:06
8
500 10
17:06-17:36
8
500 500 2,000 250 10
17:36 - 18:02b
8
Approximate total Hg level.
b Brief inadvertent injection of Cl2 to the duct occurred near the start of this time period.
3.3.7 Response Time
Response time of the AM-2 was determined in both weeks of the test, as part of the calibration/
zero drift test. The rise time and fall time were determined by recording successive AM-2 read-
ings when the delivery of elemental mercury standard gas was started or stopped, respectively.
The time to reach 95% of the final value was estimated from successive readings. The 13-minute
cycle time of the AM-2 limited the resolution of the time response determination, i.e., the
15
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response time is stated in terms of the number of 13-minute cycles needed to reach 95% of the
final value.
3.3.8 Low-Level Response
The mercury levels shown in Table 3-4 were not intended to challenge the detection limit of the
AM-2. Instead the ability of the AM-2 to detect low mercury levels was tested by a procedure
conducted on January 19. On that day, the AM-2 initially sampled RKIS flue gas with no
mercury present, but with sulfur dioxide, nitrogen oxide, and hydrogen chloride present at the
concentrations used in the first week of testing (i.e., 1,000 ppm, 250 ppm, and 25 ppm, respec-
tively; Table 3-4). Injection of mercury then began, starting with a low mercury concentration,
and stepping upwards in concentration at time intervals of about one-half hour. After the highest
mercury concentration, the mercury injection was shut off, and flue gas without added mercury
was again sampled. The mercury solutions used for this test had aqueous concentrations of
0.304 to 2.45 |ig/mL, sufficient to produce total flue gas mercury concentrations of nominally
0.57 to 4.54 (ig/m3. The actual flue gas mercury concentrations were not determined; as a result,
the nominal total mercury concentrations are used for comparison to the CEM results. The low-
level response of the AM-2 was determined based on the lowest mercury concentration detected
above the flue gas background. Note that since the AM-2 determines elemental rather than total
mercury, a quantitative comparison of AM-2 response to nominal total mercury level was not
appropriate.Table 3-7 summarizes the schedule for this test.
Table 3-7. Schedule of January 19, 2001, Low-Level Response Test
Time Period
Nominal Flue Gas Total Hg Concentration
(pg/m3)
10:44-11:39
0
11:39-12:21
0.57
12:21 - 12:56
1.13
12:56-13:33
2.27
13:33-14:15
4.54
14:15-14:55
0
3.3.9 Data Completeness
Data completeness was determined by comparing the data recovered from the AM-2 to the
amount of data expected upon completion of all portions of the verification test. Data complete-
ness was evaluated in terms of the percentage of total data recovered.
3.3.10 Setup and Maintenance Needs
Setup and maintenance needs were documented qualitatively, through observation and com-
munication with the vendor during the verification test. Factors noted included the frequency of
16
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scheduled maintenance activities, the extent of any downtime, the number of staff operating or
maintaining the CEM, and the quantity of consumables used and/or waste materials produced.
3.4 Equipment and Materials
3.4.1 Commercial Elemental Mercury Standards
Four commercial compressed gas standards of elemental mercury in nitrogen were used as stable
sources of elemental mercury for verification of day-to-day instrument calibration drift and
sampling system bias. These gases were purchased from Spectra Gases, Inc., Branchburg, New
Jersey. Spectra Gases reported the nominal prepared mercury concentration of each standard and
performed an initial analysis of each cylinder in November 2000, using a commercial CEM of a
different design than those participating in the verification test. In addition, each of these
standards was sampled before and after the verification test, using a miniature impinger train
modeled after the OH method. Collected samples were then submitted for laboratory mercury
analysis, along with the collected samples from OH flue gas sampling, to determine the cylinder
gas mercury content. The protocol for conducting this miniature impinger sampling was sub-
jected to review by ARCADIS and EPA staff and was approved by EPA prior to use in this
study.(3) Unfortunately, the pre-test analysis results showed evidence of excessive loss of mercury
in sampling the gas with the mini-impinger train. This possibility was subsequently confirmed by
conducting the sampling with a different pressure regulator on the mercury gas standard. The
regulator originally used was shown to remove some mercury from the gas and to require
extremely long equilibration times to achieve stable delivery of mercury. Consequently, the pre-
test results are not valid. Post-test results from the mini-impinger train, and from an EPA-owned
mercury CEM like the one used by the gas vendor, are shown in Table 3-8.
Table 3-8 lists the mercury standards used, along with the vendor's nominal prepared concen-
tration and initial analysis result, provided by Spectra Gases. Also listed in Table 3-8 are the
cylinder concentrations determined post verification in March 2001 by means of the mini-
impinger sampling method and an EPA-owned mercury CEM.
Table 3-8 shows generally good consistency among the gas vendor's prepared mercury con-
centrations, the gas vendor's own pre-test analysis, and the post-test analyses. In particular, the
agreement between the mini-impinger OH samples obtained post test and the vendor's prepared
concentration is within 6.4%, 3.5%, 14.1%, and 6.0%, respectively, for cylinders CC19870,
CC19931, CC20219, and CC20291. This agreement is good, considering the novel nature of
these standards and the four-month time interval between their preparation and the post-test
analysis.
Cylinders CC19931 and CC19870 were prepared at full cylinder pressure of 2,000 psig.
However, because of vapor pressure limitations of elemental mercury, cylinders CC20291 and
CC20219 were prepared with an initial pressure of only 900 psig. To assure consistent testing of
day-to-day drift, each CEM undergoing verification was challenged repeatedly with just one gas
standard in each week of testing. In addition, to assure sufficient gas to complete the testing in
each week, the gas standards were assigned to participating CEMs in such a way as to balance
17
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Table 3-8. Mercury Standard Gas Identification and Analysis Results
Pre-Test Post-Test
Cylinder
Number
Prepared
Hg°Conc.
(|ig/m3)a
Gas Vendor
Analysis
(jig/m3)
OH Mini-Train
Analysis
(jig/m3)
EPA CEM
Analysis
(jig/m3)
CC19870
12.5
14
11.7
9.3
CC19931
14.1
16
13.6
13.0
CC20219
44.0
49
50.2
47.0
CC20291
49.8
55
46.8
50.6
a Concentrations in |ig/m ! converted from ppbv concentrations stated by Spectra Gases, using a conversion factor
of 1 ppbv Hg° = 8.3 (ig/m3 at 20°C and 1 atmosphere pressure.
the consumption of all standard gases. Thus, the AM-2 monitor was challenged in the first week
of testing only with mercury standard cylinder number CC19870 and, in the second week, only
with cylinder number CC20219. In both weeks of testing, the use of those cylinders was shared
among the AM-2, another Nippon CEM, and another vendor's CEM. The final gas pressures in
the elemental mercury standards at the conclusion of testing were approximately 900 psig and
1,000 psig in cylinders CC 19870 and CC 19931, respectively, and approximately 300 psig and
550 psig in cylinders CC20219 and CC20291, respectively.
The mercury standard cylinders were used with miniature low-volume stainless steel regulators
(Spectra Gases 04-1D3EATNN-018), which were flushed for about 30 minutes before use with a
0.5 L/min flow of the standard gas. The delivery plumbing from the regulators was originally
made almost entirely of SilcoSteel® fittings, i.e., stainless steel internally coated with a layer of
glass. However, long equilibration times were observed in first supplying the 12.5 and
14.1 (ig/m3 standards to the CEMs in the first week of testing. Consequently, the delivery system
was modified to consist of all Teflon, except for the regulator itself. This change notably
improved the delivery of the mercury gas standards to the CEMs.
3.4.2 Performance Evaluation Equipment
Performance evaluation (PE) audits were conducted on several key measurements at the RKIS.
Each of those audits was conducted using a reference standard or measurement system provided
by Battelle that was independent of that used in the verification test. Table 3-9 lists the PE audit
equipment used and, when appropriate, the date of the calibration of the audit equipment prior to
the verification test. The PE audit of the OH mercury analysis was done by spiking two blank
trains with a dilution of a commercial National Institute of Standards (NIST)-traceable mercury
standard. The results of the PE audits are reported in Section 4.3.2.
18
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Table 3-9. Performance Evaluation Audit Equipment Used for the Verification Test
Measurement
Audited
PE Equipment
Date
Calibrated
Source of
Calibration
Flue gas 02 and C02
LandTec GA-90 Gas Analyzer,
Model GA 1.1 (S. No. 693)
12/19/00
Vendor
Flue gas
temperature
Fluke Model 52, (S. No. 73970010) with Type
K Thermocouple
11/29/00
Battelle
Instrument Lab
Barometric pressure
Taylor Model 2250M Aneroid Barometer
(Inventory No. LN163610)
12/20/00
Battelle
Instrument Lab
Flue gas pressure
Magnehelic Model 2005
(S. No. R51006LG64)
10/25/00
Battelle
Instrument Lab
Impinger weighing
Cenco Class T Weight Set
(200 g and 500 g weights)
1/3/01
Battelle
Instrument Lab
Ontario Hydro
mercury analysis
EM Science Atomic Absorption Standard
MX0399-2, traceable to NIST SRM #1333.
NA
Vendor
19
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Chapter 4
Data Quality
The quality of the verification data was assured by quality assurance and quality control
(QA/QC) procedures, performed in accordance with the quality management plan (QMP) for the
AMS Center(4) and the test/QA plan(1) for this verification test. Minor deviations from the test/QA
plan were documented in the verification records at the RKIS during testing. Deviations required
the approval of Battelle's AMS Center Manager. A planned deviation form was used for
documentation and approval of each of the following changes:
1. The elemental mercury gas standards were not analyzed by the University of North
Dakota Energy and Environmental Research Center because the procedure to be
used would have consumed a substantial fraction of each standard.
2. The performance evaluation for oxygen and carbon dioxide measurements at the
RKIS used an electrochemical monitor for these gases rather than paramagnetic and
infrared monitors, as stated in the plan.
3. The solution used for the injection of mercury into the RKIS duct was made with
mercuric chloride instead of mercuric nitrate.
4. As a result of the use of mercuric chloride rather than mercuric nitrate for the
injection solution, the stock solution was made up with hydrochloric acid instead of
nitric acid, and no additional acid was added in making up dilutions of the stock
solution.
5. Recovered OH samples were stored at room temperature before delivery to the
analytical laboratory, consistent with OH method requirements, instead of under
refrigeration.
6. To better test the capabilities of the mercury CEMs, the low-level response test was
conducted with flue gas mercury levels of about 0.5, 1, 2, and 4 (ig/m3 instead of 1,
2, 4, and 8 (ig/m3.
7. The RKIS carbon dioxide CEM was changed before the verification test began. A
Fuji Electric Model ZRH-1 was in place at the RKIS, instead of the Horiba VIA 510
stated in the test/QA plan.
20
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8. Calculation of interference effects in terms of "relative sensitivity" was not done,
since this calculation was inappropriate in situations where chemical trans-
formations of mercury species took place.
None of these deviations had any significant effect on the quality of the verification data.
4.1 Facility Calibrations
Continuous monitors for oxygen, carbon monoxide, carbon dioxide, nitrogen oxides, sulfur
dioxide, and hydrogen chloride are installed at the RKIS and its associated APCS to monitor
system performance and document flue gas composition. For this verification test, those monitors
were calibrated according to standard facility practice on each test day. Calibration procedures
consisted of a multipoint calibration check at the start of the day and a drift check at the end of
the day. On days when OH sampling was conducted, the drift check was also conducted after
each OH run. All calibration results were within the allowable tolerances for drift and linearity.
All calibration results were documented for inclusion in the verification data files.
Flue gas water content was determined from impinger weights in the OH trains by means of an
electronic balance located in the OH train preparation/recovery laboratory. Copies of the
calibration records for that balance were included in the data file.
Key measurements that factored directly into the verification test results were also the subject of
PE audits, as described in Section 4.3.2. Those measurements included the facility CEMs for
oxygen and carbon dioxide and the balance used for determination of water.
4.2 Ontario Hydro Sampling and Analysis
The preparation, sampling, and recovery of samples from the OH trains followed all aspects of
the QA/QC requirements in the OH method. A daily blank train was prepared, kept at either the
upstream or downstream sampling location during sample runs, and recovered along with the
sampled trains. The impinger glassware used for preparing the blank train was selected at random
each day from among the several sets used, so that blank results reflect the actual state of the
sampling equipment. All required reagent blanks were collected, and additional reagent blanks
(beyond those required in the method) of the acetone rinse reagent and of the 5% w/v potassium
permanganate called for in Section 13.2.8.3 of the OH method were collected. A sample number-
ing system was implemented that provided unique identification of each train and of each
recovered sample from that train. This numbering system was implemented by means of pre-
printed labels applied to sample containers arranged in order of sample recovery for each train.
The recovered samples were delivered to the analytical laboratory within about 24 hours after
collection. Oxford Laboratories, which conducted the OH analyses, similarly adhered to all
requirements of the OH analytical process. Replicate analysis of samples was performed as
required by the OH method, and all results met the 10% acceptance criterion. The analytical
results for each set of analyses were accompanied by data quality documentation that reported the
laboratory calibration procedures and results applicable to those analyses.
21
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Because of the importance of the OH data in this verification, the following sections present key
data quality results from the OH data.
4.2.1 Ontario Hydro Precision
The results of the OH flue gas sampling and analysis are shown in Tables 4-la-c and 4-2a-c, for
the first and second weeks of verification testing, respectively. Tables 4-la and 4-2a show the
elemental mercury results, Tables 4-lb and 4-2b the oxidized mercury results, and Tables 4-lc
and 4-2c the total vapor-phase mercury results from the OH runs. Particulate mercury, deter-
mined on one OH particulate filter at each location in each OH run, was not detectable during the
first week of verification testing. During the second week of testing, of the 18 filters analyzed for
particulate mercury, 11 showed mercury of less than 0.5 (ig/m3, five showed levels 0.5 to
1 (ig/m3, and two showed levels of 1.0 to 1.5 (ig/m3. Thus, particulate mercury was a negligible
fraction of the total mercury present in RKIS flue gas.
Inspection of the data in these tables shows that, in nearly all cases, the agreement between
duplicate OH results (i.e., the precision of the OH method) was good at both the upstream and
downstream sampling locations. Furthermore, the mercury levels determined at the upstream
location generally agreed closely with those at the downstream location. This observation indi-
cates that little loss of mercury or change in mercury speciation occurred during the transit of flue
gas from one location to the other. The variability in OH results was larger in the second week of
sampling (Tables 4-2a-c) than in the first week (Tables 4-la-c). This undoubtedly results in part
from the greater proportion of oxidized mercury present in the second week. The oxidized
mercury is more difficult to transport and sample, and the proportion of oxidized mercury may
have varied due to small variations in RKIS conditions (e.g., temperature). Day-to-day variations
in mercury results in the second week are also due in part to changes in delivery conditions. Most
notably, the pump used to inject the mercury solution into the RKIS failed during OH Run 9 on
January 22 and was replaced with a different pump. The higher total mercury levels measured on
January 23 and 24, relative to those on January 22, are probably due to a slightly higher delivery
rate on those days.
To quantify the characteristics of the OH reference data before using them for verification of the
Nippon AM-2, the OH data were subjected to a statistical analysis, addressing three issues:
¦ The precision of the duplicate OH results at both the upstream and downstream sampling
locations
¦ The agreement between the mercury levels determined by the OH method at the upstream
and downstream sampling locations
¦ The identification of any outliers in the data.
These issues were addressed separately for the elemental, oxidized, and total mercury data.
22
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Table 4-la. Elemental Mercury Results from OH Sampling in the First Week of
Verification Testing
Elemental Hg (pg/m3)
Upstream
Downstream
Date
Port Location
2A
2C
8A
8C
1/15/01
Run 1
6.78
6.49
6.28
6.29
1/15/01
Run 2
6.20
6.23
6.18
5.98
1/16/01
Run 3
6.51
6.52
6.09
6.12
1/16/01
Run 4
6.43
7.00
7.55
6.50
1/17/01
Run 5
6.31
6.53
6.03
5.95
1/17/01
Run 6
6.10
6.56
5.29
5.99
Table 4-lb. Oxidized Mercury Results from OH Sampling in the First Week of
Verification Testing
Oxidized Hg (pg/m3)
Upstream
Downstream
Date
Port Location
2A
2C
8A
8C
1/15/01
Run 1
1.11
1.11
1.23
1.07
1/15/01
Run 2
0.93
1.11
1.20
1.36
1/16/01
Run 3
1.05
1.05
1.25
1.12
1/16/01
Run 4
1.09
0.99
1.40
1.26
1/17/01
Run 5
1.32
1.29
1.42
1.30
1/17/01
Run 6
1.70
1.42
1.64
1.68
23
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Table 4-lc. Total Mercury Results from OH Sampling in the First Week of Verification
Testing
Total Hg (pg/
m3)
Upstream
Downstream
Date
Port Location
2A
2C
8A
8C
1/15/01
Run 1
7.89
7.60
7.51
7.36
1/15/01
Run 2
7.13
7.34
7.38
7.34
1/16/01
Run 3
7.56
7.57
7.34
7.24
1/16/01
Run 4
7.52
7.99
(S.!)T>
7.76
1/17/01
Run 5
7.63
7.82
7.45
7.25
1/17/01
Run 6
7.80
7.98
6.93
7.67
a Shaded cells indicate data excluded as outliers.
Table 4-2a. Elemental Mercury Results from OH Sampling in the Second Week of
Verification Testing
Elemental Hg (pg/m3)
Upstream Downstream
Date
Port Location
2A
2C
8A
8C
1/22/01
Run 7
11.1
12.4
11.4
11.6
1/22/01
Run 8
14.3
15.1
13.6
11.5
1/22/01
Run 9
25.1
20.9
27.4
27.4
1/23/01
Run 10
:;.r>
7.0
6.0
6.9
1/23/01
Run 11
8.2
9.3
7.2
7.5
1/23/01
Run 12
8.0
8.1
6.7
3.7
1/24/01
Run 13
6.8
7.2
6.4
6.2
1/24/01
Run 14
4.9
5.4
6.3
5.7
1/24/01
Run 15
6.7
6.9
7.6
5.2
a Shaded cells indicate data excluded as outliers.
24
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Table 4-2b. Oxidized Mercury Results from OH Sampling in the Second Week of
Verification Testing
Oxidized Hg (pg/m3)
Upstream
Downstream
Date
Port Location
2A
2C
8A
8C
1/22/01
Run 7
61.4
67.3
63.3
69.1
1/22/01
Run 8
71.2
75.2
67.2
67.4
1/22/01
Run 9
46.5
2
44.0
46.0
1/23/01
Run 10
60.5
!)7.()
96.3
97.7
1/23/01
Run 11
111.2
110.2
100.5
98.5
1/23/01
Run 12
113.8
114.3
105.5
70.5
1/24/01
Run 13
88.0
88.0
85.6
84.5
1/24/01
Run 14
77.7
87.7
81.6
67.5
1/24/01
Run 15
86.9
91.4
84.8
81.8
a Shaded cells indicate data excluded as outliers.
Table 4-2c. Total Mercury Results from OH Sampling in the Second Week of Verification
Testing
Total Hg (pg/m3)
Upstream Downstream
Date
Port Location
2A
2C
8A
8C
1/22/01
Run 7
72.5
79.7
74.7
80.7
1/22/01
Run 8
85.4
90.2
80.7
78.9
1/22/01
Run 9
71.5
51.1
71.4
73.4
1/23/01
Run 10
61.0
104.0
102.3
104.6
1/23/01
Run 11
119.4
119.5
107.7
106.1
1/23/01
Run 12
121.8
122.5
112.2
71.1
1/24/01
Run 13
94.9
95.2
92.0
90.7
1/24/01
Run 14
82.6
93.1
87.9
73.2
1/24/01
Run 15
93.6
98.3
92.4
87.0
a Shaded cells indicate data excluded as outliers.
25
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The precision of duplicate OH trains at both sampling locations was assessed by Student's t-tests.
Nonparametric Wilcoxon Rank Sum tests were also used to compare the results from the t-tests.
The outcome of this analysis was that, in the first week of verification testing, the average agree-
ment of paired OH trains was within 2.7% for elemental mercury, within 4.4% for oxidized
mercury, and within 1.7% for total mercury. In the second week of testing, agreement of paired
trains was within 14.8% for elemental mercury, within 7.2% for oxidized mercury, and within
8.1% for total mercury. These results are very good considering the low concentrations of
mercury species and the difficulty of preparing and sampling oxidized mercury in the flue gas.
The statistical analysis found no significant differences between the paired OH results (i.e.,
Port A vs Port C) for elemental, oxidized, or total mercury at either the upstream or the
downstream sampling location.
Evaluation of upstream/downstream differences in the OH results used an analysis of variance
(ANOVA) approach. Student's t-tests and Nonparametric Wilcoxon Rank Sum tests were also
used to compare the results of the ANOVA. The statistical analysis found no significant differ-
ences between the upstream and downstream levels of elemental or total mercury in either week
of testing. The upstream and downstream elemental mercury levels agreed on average within
4.9% and within 7.0% in the first and second week of testing, respectively. Those of total
mercury agreed within 2.0% and within 4.3%, respectively. Similarly, in the second week of
testing, the upstream and downstream levels of oxidized mercury agreed within 4.2%. On the
other hand, a significant upstream/downstream difference of 11.2% in oxidized mercury was
found in the first week of testing. However, it must be noted that this resulted from an average
absolute difference of only 0.15 (ig/m3 at oxidized mercury levels of 1.2 to 1.3 (ig/m3. This
absolute difference is comparable to the detection limit of the OH method. Although a significant
upstream/downstream difference may be indicated by the statistical tests, the agreement between
upstream and downstream oxidized mercury levels is still very good considering the low mercury
levels present.
The analysis for outliers in the OH data relied on a studentized residual approach as the primary
criterion, with COVRATIO and DFFITS statistics® as secondary criteria. A mercury measure-
ment was considered an outlier if the primary criterion and at least one of the secondary criteria
were met. The aim of this analysis was to identify OH results that were not accurate indications
of the flue gas mercury content, rather than to eliminate data that resulted from facility or other
variations. For example, the statistical analysis identified all the elemental mercury results from
OH Run 9 (20.9 to 27.4 (ig/m3, Table 4-2a) as outliers relative to other data from the second
week of testing. However, those values are thought to arise from the failure of the mercury
solution delivery pump in that run and the interruption and resumption of mercury delivery to the
RKIS. That is, the OH elemental mercury results from Run 9 are thought to reflect actual test
facility variability. As a result, most of the OH results from Run 9 have been retained in the data
set. On the other hand, the analysis did disclose a few outliers in the OH data, which are shown
in Tables 4-la-c and 4-2a-c in shaded cells. Those values were excluded from the calculations
used to verify mercury CEM performance on the basis of the duplicate precision and upstream/
downstream differences for individual results. In this analysis, the precision of paired results was
compared to the average precision results stated above. Individual values showing differences
greater than three times the average precision were excluded. As Tables 4-1 and 4-2 show, this
26
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procedure excluded a few individual values differing sharply from the other simultaneous OH
results.
As a result of these analyses of the OH data, it was concluded that each OH result, excluding
outliers, could be taken as a separate and independent measurement of flue gas composition. The
result of excluding the outlying values is that, for the first week of testing, 24 values for
elemental and oxidized mercury were used in the verification and 23 values for total mercury.
For the second week of testing, 34 values for elemental mercury and 33 values for oxidized and
total mercury were used.
4.2.2 Ontario Hydro Blank Trains
Table 4-3 shows the analytical results from the six blank OH trains collected during the verifica-
tion test. This table lists the flue gas concentrations (in (ig/m3) that would be inferred from the
blank train results, assuming gas sample volumes of 2 m3 in the first week of testing and 1 m3 in
the second week. Results are shown for oxidized mercury (from the potassium chloride
impingers of the OH trains) and for elemental mercury (from both the peroxide and potassium
permanganate impingers of the OH trains). The detection limit for mercury in these samples was
0.1 |ig. As Table 4-3 indicates, the great majority of blank train results were below the detection
limit, and the few detectable mercury levels were negligible when compared to the levels actually
found in the flue gas samples (Section 4.2.1). These results indicate that OH samples were not
exposed to contamination sources during sample recovery, handling, and analysis.
Table 4-3. Equivalent Flue Gas Mercury Concentrations (jig/m3) Found in Blank Ontario
Hydro Trains
Date
Train ID
Oxidized Hg
Hg° (HA)
Hg° (KMnOJ
1/15/01
I-GR-OHI-la
< 0.05
< 0.05
0.29
1/16/01
I-GR-OHA-2a
<0.05
<0.05
<0.05
1/17/01
I-GR-OHB-3a
<0.05
<0.05
<0.05
1/22/01
II-GR-OHI-4b
<0.1
<0.1
0.31
1/23/01
II-GR-OHI-5b
<0.1
<0.1
<0.1
1/24/01
II-GR-OHI-6b
0.12
<0.1
<0.1
a Equivalent flue gas concentrations calculated from blank train results using assumed sample volume of 2 m3.
b Equivalent flue gas concentrations calculated from blank train results using assumed sample volume of 1 m3.
4.2.3 Ontario Hydro Reagent Blanks
A total of 39 samples of the various OH reagents were collected for analysis between January 15
and January 24, covering all impinger reagents and train rinse solutions. Mercury was found at
detectable levels in only two of those 39 samples. The levels found in those two samples were
27
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negligible in terms of their equivalent flue gas mercury concentration when compared to the
concentrations found in the actual flue gas samples (Section 4.2.1).
4.3 Mercury Mass Balance
Because of the potential for loss of mercury from the flue gas, a valuable QA exercise is to
calculate the mass balance of mercury in the RKIS facility. This was done by comparing the total
mercury result from each OH train (Section 4.2.1) to the expected total mercury level in the
RKIS flue gas, based on the duct flow rates and the concentrations and flow rates of the injection
solutions. The ratio of the OH total mercury to the expected total mercury, expressed as a
percentage, is defined as the percent recovery of the injected mercury. Table 4-4 summarizes this
comparison, showing percent recovery values for both the upstream and downstream OH results
for both weeks of the verification test. In each case, the mean and standard deviation, maximum,
minimum, and median of the percent recovery values are shown. The outliers identified in
Section 4.2.1 were excluded from this calculation.
Table 4-4. Percent Recovery of Total Mercury Injected into the RKIS
Period
Parameter
Upstream Recovery (%)
Downstream Recovery (%)
Week One
Mean (Std. Dev.)
112.2 (13.1)
111.3 (8.7)
Maximum
137.7
122.2
Minimum
100.8
99.5
Median
105.0
113.0
Week Two
Mean (Std. Dev.)
110.7 (14.2)
112.1 (14.4)
Maximum
134.4
136.2
Minimum
91.2
87.3
Median
108.4
110.8
Table 4-4 shows that the mass balance for mercury injected into the RKIS was good. Over the
entire verification test, the minimum mass balance value was 87.3% and the maximum was
137.7%. For both sampling locations in both weeks of testing, the average mass balance was
about 111 to 112%. These results confirm that mercury injected into the RKIS was not lost, and
in particular confirm that there was no significant difference in mercury levels between the
upstream and downstream sampling locations. Table 4-4 does indicate that the OH results were
usually higher than the expected mercury level by about 10 to 12%, on average.
28
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4.4 Audits
4.4.1 Technical Systems Audit
Battelle's Quality Manager performed an internal technical systems audit (TSA) of the verifica-
tion test on January 16 and 17, 2001, during the first week of testing. The TSA ensures that the
verification test is conducted according to the test/QA plan(1) and that all activities associated
with the test are in compliance with the AMS Center QMP.(4) On January 16 the Battelle Quality
Manager visited the RKIS test site, where he toured the test area, observed the performance of
OH method sampling, reviewed Battelle notebooks and calibration gas certificates, reviewed
facility CEM calibration records, and met with the ARCADIS Quality Manager. On January 17,
the Battelle Quality Manager visited Oxford Laboratories and reviewed the OH analysis proce-
dures in use there. All the observations of the Battelle Quality Manager were documented in a
TSA report. There were no findings of any issues that could adversely affect verification data
quality. The records concerning the TSA are permanently stored with the Battelle Quality
Manager.
In addition to the internal TSA performed by Battelle's Quality Manager, an external TSA was
conducted by EPA on January 23, 2001. The EPA external TSA included all the components of
the internal TSA, except that EPA QA staff did not visit Oxford Laboratories. The findings of
this TSA were documented in a report submitted to the Battelle Quality Manager. No adverse
findings were noted in this external TSA.
4.4.2 Performance Evaluation Audits
A series of PE audits was conducted on several different measurements at the RKIS to assess the
quality of the measurements made in the verification test. These audits were performed by
Battelle staff and were carried out with the cooperation of EPA and ARCADIS staff. These
audits addressed only those measurements that factored into the data used for verification. Each
PE audit was performed by analyzing a standard or comparing to a reference independent of
standards used during the testing (see Section 3.4.2). Each PE audit procedure was performed
once during the verification test, with the exception that OH trains were spiked once in each
week of testing. Table 4-5 summarizes the PE audits on several measurement devices of the
RKIS; Table 4-6 summarizes the PE audit results from spiking OH trains.
Table 4-5 shows that all the PE audit results on measurement devices were well within the
required tolerances stated in the test/QA plan.(1) The PE audit for oxygen and carbon dioxide was
conducted by sampling the same gas entering the facility oxygen and carbon dioxide CEMs,
using a portable monitor for those gases. This was done using a "T" fitting at the inlet of each
facility CEM, so that the readings from the portable audit monitor and the CEMs were obtained
in simultaneous sampling of the flue gas. Duct temperature measurement was audited by insert-
ing a calibrated thermocouple into the same location in the duct as the temperature probe used for
Method 2 velocity measurements. The small temperature difference observed probably resulted
from the inability to place the two probes at exactly the same location in the small duct.
29
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Table 4-5. Summary of PE Audits on Mercury CEM Verifications
Measurement
Audited
Date
Audit Method
Observed
Agreement
Required
Agreement
Flue gas 02
1/19/01
Comparison to independent 02
measurement
0.1% 02
1% 02
Flue gas C02
1/19/01
Comparison to independent C02
measurement
5% of C02
reading
10% of C02
reading
Flue gas
temperature
1/18/01
Comparison to independent
temperature measurement
1.0%
absolute T
2%
absolute T
Local barometric
pressure
1/15/01
Comparison to independent
barometric pressure measurement
0.43 " H20
0.5 " H20
Flue gas pressure
1/19/01
Comparison to independent
pressure measurement
0.02 " H20
0.5 " H20
Impinger weights
(electronic
balance)
1/18/01
Weighing certified weights
0.03%
(0.14 g at
500 g)
Larger of 1%
or 0.5 g
Barometric pressure was audited using a calibrated aneroid barometer. Flue gas pressures were
audited using a Magnehelic gauge installed in parallel with a set of similar gauges used for the
Method 2 velocity determinations. Gauges with ranges of 0 to 0.25, 0 to 0.5, and 0 to 2 inches of
water were audited. The PE audit of the electronic balance used certified weights of 200 and
500 grams; the observed agreement shown in Table 4-5 is for the 500-gram weight, which
showed the greater percentage deviation.
The PE audit of the OH train mercury analysis was conducted once in each week of the test, and
the results are summarized in Table 4-6. In the first week, impingers 1 (KC1), 4 (H202/HN03),
and 5 (KMn04/H2S04) of a blank OH train (I-LB-ST-1) were each spiked with 1 mL of a NIST-
traceable solution containing 10 |ig/mL of mercury. In the second week, the same impingers of a
blank train (II-LB-ST-2) were each spiked with 3 mL of the same solution. As Table 4-6 shows,
recovery of the spiked mercury was well within the 10% tolerance stated in the test/QA plan (1)
for all spiked samples except the potassium permanganate impinger from the first spiked train.
These results indicate that the OH analysis was accurate at spiked mercury levels comparable to
those collected in the actual OH sampling. The high readings obtained in analysis of the
potassium permaganate impinger from the first spiked train may have been caused by the need to
spike that train twice. That is, train I-LB-ST-1 was originally spiked on January 18 and stored
overnight for recovery.
However, inadvertent pressurization caused a spillover between impingers 4 and 5 overnight. As
a result, the train was emptied, rinsed, refilled, and spiked on January 19, as indicated in
Table 4-6. The higher-than-expected mercury level in impinger 5 may have resulted from
contamination during this process.
30
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Table 4-6 Results of PE Audit of OH Train Analysis
Analyses
Date
Train
Impinger"
Number
Spikeb
(Pg)
1st
(Pg)
2nd
(Pg)
Average
(Pg)
Observed
Agreement0
(%)
Required
Agreement
(%)
1/19/01
I-LB-ST-1
1
10
9.75
9.53
9.64
-3.6
10
4
10
9.85
9.61
9.73
-2.7
10
5
10
11.6
12.0
11.8
18
10
1/24/01
II-LB-ST-2
1
30
29.6
29.9
29.75
-0.8
10
4
30
29.9
30.0
29.95
-0.2
10
5
30
28.7
28.5
28.6
-4.7
10
" Impinger 1 = KC1, 4 = H202, 5 = KMn04.
b Amount of mercury injected based on dilution of NIST-traceable standard.
c Observed Agreement = (Average analysis - Spike)/Spike x 100.
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4.4.3 Data Quality Audit
Battelle's Quality Manager audited at least 10% of the verification data acquired in the verifi-
cation test. The Quality Manager traced the data from initial acquisition, through reduction and
statistical comparisons, to final reporting. All calculations performed on the data undergoing
audit were checked.
32
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Chapter 5
Statistical Methods
The following statistical methods were used to reduce and generate results for the performance
factors.
5.1 Relative Accuracy
The relative accuracy (RA) of the AM-2 with respect to the elemental and total mercury results
of the reference (OH) method was assessed by the following equation, which is incorporated in
EPA performance specifications for continuous emission monitoring systems:
11 ,a d
\d\ + Kx —
J" ^ mno/. ^
RA = x 100%
where d refers to the arithmetic difference between corresponding OH and AM-2 results, and x
corresponds to the OH result. Sd denotes the sample standard deviation of the differences, while
tan4 is the t value for the 100(1 - a)th percentile of the distribution with n-1 degrees of freedom.
To calculate RA, the OH and corresponding AM-2 results were paired, and the differences
between the paired results were calculated. Then, the absolute mean {ct) and standard deviation
(Sd) of those differences were calculated. The mean of the OH results (a;) was calculated, and the
value of tc^_1 was taken from appropriate tables for the relevant values of n and a. The RA was
determined for an a value of 0.025 (i.e., 97.5% confidence level, one-tailed). RA was calculated
separately for the first and second week of testing. The OH results used for the RA calculation
were as stated in Section 4.2.1.
5.2 Correlation with Reference Method
The degree of correlation of the AM-2 with the reference method results was assessed in terms of
the coefficient of determination (r2), which is the square of the correlation coefficient (r). This
33
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calculation was made separately for the first and second week of testing, and also for the full data
set from both weeks of testing.
5.3 Precision
Precision was calculated in terms of the percent relative standard deviation (RSD) of a series of
CEM measurements made during stable operation of the RKIS, with mercury injected at a
constant level into the combustion zone. During each OH sampling run, all readings from the
AM-2 were recorded, and the mean and standard deviations of those readings were calculated.
Precision (P) was determined as
where S is the standard deviation of the readings and X is the mean of the readings.
5.4 Calibration/Zero Drift
Calibration and zero drift were determined in a relative sense, rather than as deviations from an
absolute standard, using the elemental mercury gas standards and high-purity nitrogen as zero
gas. In the first week, nine elemental mercury standard readings, and nine zero readings, were
used for this calculation. In the second week, seven readings of each type were available for this
calculation. Drift was calculated in terms of the RSD, as
where x is the mean, and S the standard deviation, of the daily readings on standard or zero gas.
This calculation, along with the range of the data, indicated the day-to-day variation in zero and
standard readings.
5.5 Sampling System Bias
Sampling system bias was calculated as the difference in CEM response when sampling
elemental mercury standard gas through the entire sample interface, compared to that when
sampling the same gas directly at the analyzer, expressed as a percentage of the response at the
analyzer. That is,
5
P = = xl00
X
(3)
RSD = — jc 100
(3)
B = Rsl - Ra x 100
(4)
34
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where B is the percent bias, Rsi is the reading when the standard gas is supplied at the sampling
inlet, and Ra is the reading when the standard is supplied to the analyzer. As described in
Section 3.3.5, this check was conducted using another Nippon CEM undergoing verification,
which showed an identical inlet configuration with the AM-2, but which provided much faster
time response. The results of this bias check are summarized in Section 6.5, and the bias check
data are presented elsewhere.®
5.6 Interferences
Interferences were determined during sampling of combustion flue gas, in terms of the difference
in response to a constant mercury level when potential interferant gases were added or removed.
Interferences were assessed in terms of the effect of the interferant species (N0X, CO, S02, HC1,
Cl2) introduced alone or together into the flue gas. The interferant levels were established by
means of the facility CEM responses for each interferant, as described in Section 3.2.1.
5.7 Response Time
The response time was determined as the time after a step change in mercury concentration when
the AM-2 reading reached a level equal to 95% of that step change. Both rise time and fall time
were determined. The AM-2 response times were determined in conjunction with a calibra-
tion/zero drift check, by starting or stopping delivery of the elemental mercury standard gas to the
AM-2's sampling interface, recording readings until stable readings were obtained and then
estimating the 95% response time.
5.8 Low-Level Response
The ability of the AM-2 to determine low mercury concentrations was assessed by comparing
responses at successive nominal total mercury levels of 0, 0.57, 1.13, 2.27, and 4.54 (ig/m3 in the
RKIS flue gas. This test was conducted in a flue gas matrix containing elevated levels of sulfur
dioxide, nitrogen oxides, and hydrogen chloride, as described in Section 3.3.8. The lowest
mercury level producing a response above that with no mercury added is of interest in this test.
Since the AM-2 determines elemental mercury, and only the nominal total mercury
concentrations were known, a quantitative comparison of AM-2 responses to the nominal
concentrations was not conducted.
35
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Chapter 6
Test Results
The results of the verification test of the Nippon AM-2 mercury CEM are presented in this
section, based upon the statistical methods shown in Chapter 5.
6.1 Relative Accuracy
Table 6-1 shows the average elemental mercury results obtained from the AM-2 during the
period of each OH sampling run. These averages were calculated from eight or nine AM-2
readings obtained during each two-hour OH run in the first week of testing, and from four or five
AM-2 readings in each one-hour OH run, in the second week. The AM-2 averages were calcu-
lated by subtracting from each data point the daily average zero gas reading of the AM-2 (from
the calibration/zero drift results in Section 6.4), and then weighting each five-minute sampling
result by the fraction of its sampling period that overlapped the OH run. For example, an AM-2
sampling interval that overlapped the start of the OH run by only three minutes was given 3/5 the
weight of an interval that was completely within the OH sampling period. The zero-corrected and
averaged results are shown in Table 6-1 and may be compared to the OH elemental mercury
results shown in Tables 4-la and 4-2a.
The results of the calculation of relative accuracy for the AM-2 are shown in Table 6-2, which
provides separate relative accuracy results for the two weeks of testing. In the great majority of
cases, the AM-2 readings were slightly lower than the corresponding OH results, in both weeks
of testing. A relative accuracy of about 14% was found for the AM-2 CEM in the first week of
testing, with elemental mercury levels of approximately 6 to 7 (ig/m3 (as indicated by OH results,
Table 4-la). In other words, agreement between the AM-2 and the OH results was within about
1 (ig/m3 throughout the first week of testing. A relative accuracy of about 23% was found in the
second week, with OH elemental mercury levels ranging from about 5 to 25 (ig/m3 (Table 4-2a).
The relative accuracy in the second week was greatly affected by relatively poor agreement of the
AM-2 with the OH results for Runs 7 and 8. If those two runs were excluded from the calcula-
tion, the relative accuracy value for the second week would be 12.3%. The reason for the poorer
accuracy in those two runs, relative to all others, is not known.
In considering these results, it should be noted that the bias in transfer of elemental mercury
through the AM-2 inlet was found to be about -7% (see Section 6.5). This negative bias due to
the inlet system is likely a substantial contributor to the observed relative accuracy results.
36
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Table 6-1. Average Elemental Mercury Results from Nippon AM-2 During OH Sampling
Runs
Date
OH Run Number
AM-2 Hg° (pg/m3)
January 15
1
6.09
2
5.57
January 16
3
5.81
4
5.68
January 17
5
5.54
6
4.98
January 22
7
8.19
8
7.8
9
24.8
January 23
10
6.25
11
5.96
12
6.63
January 24
13
6.00
14
5.78
15
6.55
Table 6-2. Relative Accuracy Results for the Nippon AM-2a
Testing Period
Relative Accuracy (%)
Week One
14.2
Week Two
22.7b
a Elemental mercury only.
b When OH Runs 7 and 8 are excluded, relative accuracy for Week Two = 12.3%.
37
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6.2 Correlation
The correlation of the AM-2 monitor with the OH reference method also was calculated using the
elemental mercury results shown in Table 6-1. A correlation plot of the AM-2 and OH results
from each week of testing is shown in Figure 6-1. This figure also shows the linear regression
results and the correlation coefficients (r) for elemental mercury in each week, and in both weeks
combined. The resulting coefficient of determination (r2) for data from the first week was 0.155,
reflecting the limited range of elemental mercury concentrations in the first week. The r2 value
for data from the second week was 0.869. The data set from both weeks combined is the largest
and has the widest range of data values, and consequently is the most appropriate for calculation
of correlation. When all data from both weeks were combined (58 total measurements of
elemental mercury), an r2 value of 0.878 was found.
30
~ Elemental Hg, Week One
~ Elemental Hg, Week Two
25
Week Two
y = 0.904x - 0.567
r = 0.932
20
CO
£
O)
3
Both Weeks
y = 0.885x-0.212
r = 0.937
3 15
Q)
a:
CM
<
10
5
Week One
y = 0.319x + 3.59
r = 0.394
0
0
5
10
15
20
25
30
Ontario Hydro Result, ug/m3
Figure 6-1. Correlation Plot of AM-2 and OH Results for Each Week of Testing
6.3 Precision
The precision of AM-2 response for elemental mercury was calculated from the repeated
analyses of flue gas under nominally constant conditions during the 15 OH sampling runs.
Table 6-3 shows the calculated precision results, in terms of the percent relative standard
deviation (% RSD) of the readings in each run. The mean and standard deviations of the readings
are also shown. These values were calculated using zero-corrected data, as was done in the
calculation of relative accuracy; however, in this case, the AM-2 sampling periods were not
weighted when they partially overlapped the start or end of the OH run. That is, all five-minute
AM-2 sampling intervals over the time period of the OH run were treated equally, whether they
38
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were completely within the OH sampling run or not. As a result, the average values shown in
Table 6-3 may differ slightly from the AM-2 results shown in Table 6-1. The results shown for
the AM-2 in Table 6-3 are each calculated from eight or nine readings in the first week of testing
and from four or five readings in the second week.
The aim of this test was to assess the precision of the AM-2 under constant flue gas conditions.
Unfortunately, occasional spikes in mercury concentration did occur during testing. When these
spikes were corroborated by the response of multiple mercury CEMs as having been caused by
the facility, or were clearly associated with occurrences at the facility, the spikes were removed
from the data before precision was calculated. On the other hand, excursions of a single CEM
that were not coincident with similar excursions of other CEMs, or not attributable to any
occurrence at the RKIS, were not removed from the data.
Table 6-3 shows that the precision of the AM-2 results was within 15% RSD in 13 of the 15 OH
sampling periods and was within 10% RSD in 11 of the 15 periods. These results indicate the
combined variability of the AM-2 and the flue gas mercury levels and show that, in most cases,
the RKIS facility maintained highly stable mercury levels. The precision results for OH Run 9 in
Table 6-3 exclude a large spike in mercury level that was caused by the failure of the mercury
solution delivery pump. The results for that run may still include some increased variability
caused by the impending failure of that pump. The AM-2 showed a sharp decrease in reported
elemental mercury from the start to the end of OH Run 10 that resulted in a relatively large
percent RSD, and that could not be traced to any occurrence in the test facility. In Runs 11 and
13, simultaneous spikes in mercury were observed with the AM-2 and other CEMs, so those data
were removed from the calculation.
6.4 Calibration/Zero Drift
The daily AM-2 readings on zero gas and elemental mercury standard gas are listed in Table 6-4.
The data from the two weeks of testing are listed separately, because of the different standard
gases used. Table 6-5 summarizes the calibration/zero drift results, in terms of the mean,
standard deviation, percent RSD, maximum, and minimum of the zero and standard gas
responses in each week. The first analysis of the mercury standard gas in the first week was
excluded from the drift calculation because, as described in Section 3.4.1, the materials and
procedure for delivering that standard did not allow proper equilibration in that first run.
Tables 6-4 and 6-5 show that the AM-2 gave a stable response to both zero and standard gases in
the test. In particular, variation in response to both of the elemental mercury standard gases
showed a 4% RSD or less. This observation shows the stability of the AM-2 and also supports
the utility of the elemental mercury standards for confirmation of CEM stability. The mercury
concentrations in the gas standards are not known absolutely, but the average mercury concentra-
tions reported by the AM-2 for the two standard gases (15.5 and 55.3 (ig/m3, respectively) are
within 11 and 13%, respectively, of the concentrations of 14 and 49 (ig/m3, based on analysis by
the gas vendor (Table 3-8, Section 3.4.1).
39
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Table 6-3. Precision Results for the Nippon AM-2
Date
OH Run
Number
Mean Hg° (pg/m3)
Std. Devn. (pg/m3|
RSD %)
January 15
1
5.94
0.75
12.6
2
5.60
0.82
14.7
January 16
3
5.81
0.30
5.1
4
5.68
0.21
3.8
January 17
5
5.54
0.34
6.1
6
4.98
0.18
3.7
January 22
7
8.26
0.51
6.2
8
7.90
0.33
4.2
9
10.13
2.66
26.3a
January 23
10
6.11
2.46
40.3
11
4.45
0.10
2.3a
12
6.40
0.50
7.8
January 24
13
5.42
0.26
4.9a
14
5.68
0.18
3.2
15
6.49
0.19
3.0
a Brief spikes in data removed prior to calculation of precision.
6.5 Sampling System Bias
Because of the slow cycle time of the AM-2, it was not used to determine the bias of the
sampling system shared by the AM-2 and another Nippon mercury CEM. Instead, since all
aspects of the two inlet paths were identical, the other Nippon CEM was used for this purpose,
and the bias data are presented in the verification report for that CEM.(6) The observed bias in the
transport of elemental mercury through the entire inlet to the Nippon CEMs was found to be
-7.4%, using the low level standard on January 19, and -6.8%, using the high level standard on
January 25.
40
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Table 6-4. Zero and Standard Gas Responses of the Nippon AM-2
Week One
Week Two
Zero Gas
Standard Gas
Zero Gas
Standard Gas
Date
(Pg/m3)
(Pg/m3)
Date
(Pg/m3)
(Pg/m3)
January 15
0.19
11.3a
January 22
1.38
57.6
0.32
14.7
1.97
54.8
January 16
0.33
15.0
January 23
2.93
54.1
0.69
15.9
2.69
53.0
January 17
0.67
15.9
January 24
2.22
53.5
0.96
15.2
2.75
57.2
January 18
0.67
16.7
January 25
0.88
56.7
0.63
15.4
January 19
0.62
15.2
a This value excluded from calculation of drift; delivery procedure for elemental mercury standard gas not properly
equilibrated.
Table 6-5. Summary of Calibration/Zero Drift Results for the Nippon AM-2
Mean Std. Devn. Relative Std. Devn. Maximum Minimum
Testing Period (pg/m3) (pg/m3)
(Pg/m3) (pg/rn3)
Week One
Zero Gas 0.56
Standard Gas 15.5
Week Two
Zero Gas 2.12
Standard Gas 55.3
0.24
0.64
0.76
1.87
42.6
4.1
36.0
3.4
0.96
16.7
2.93
57.6
0.19
14.7
0.88
53.0
6.6 Interference Effects
The effect of interferences was tested by injecting a constant level of mercury into the RKIS and
altering the levels of several interferants, as described in Section 3.3.6. Figure 6-2 illustrates the
response of the AM-2 during this test on January 18. The dashed vertical lines indicate the time
periods in which each of the interferants or combination of interferants was introduced. The cycle
41
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12
Hg only NO CO S02 HCI Cl2 NO+CI2 All Hg only
I 500 ppm I 500ppm I 2,000 ppm I 250 ppm I 10 ppm
11:31:12 12:43:12 13:55:12 15:07:12 16:19:12 17:31:12 18:43:12
Time of Day
Figure 6-2. Nippon AM-2 Response in Interference Test, January 18, 2001
time of the AM-2 limits the number of data points obtained at each test condition, but the
behavior with high levels of the several interferant gases is apparent.
It must be stressed that the AM-2 responds only to elemental mercury. Although the total
mercury injection rate to the RKIS was constant in this test, no independent measurement was
made of the elemental/oxidized speciation of the mercury in the flue gas. Also note that changes
in injected interferants occasionally produced spikes or transients at the transition points from
one interferant to the next.
Figure 6-2 shows that neither 500 ppm nitrogen oxide nor 500 ppm carbon monoxide had a
significant effect on the elemental mercury response of the AM-2. The response decreased only
slightly with the presence of 2,000 ppm of sulfur dioxide. Addition of 250 ppm hydrogen
chloride to the duct caused a decrease in elemental mercury response of about 25%. Stabilization
of the hydrogen chloride concentration at the target level took several minutes, and this is
reflected in the AM-2 response in this period, which stabilized as the hydrogen chloride level
rose and became constant. Injection of 10 ppm of chlorine sharply reduced the elemental mercury
response. Addition of nitric oxide along with the chlorine initially produced a sharp increase in
elemental mercury response on the AM-2, but this is probably the result of an inadvertent drop in
the chlorine injection rate that occurred at this time, and not to any chemical effect of the added
nitric oxide. Once injection rates were stable, the AM-2 responses were similar to those with
chlorine alone, and thus any effect of added nitric oxide on the effect of the chlorine was small.
Figure 6-2 also shows that when all of the interferants were injected together at the indicated
target levels, the AM-2 response increased, and showed good agreement with the response to
mercury in the absence of interferants. The AM-2 responses with all interferants present show
42
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that the AM-2 is not subject to serious interferences from high levels of several key pollutants in
combustion emissions.
6.7 Response Time
The rise and fall times of the AM-2 response were tested as part of the zero and standard gas
checks done to assess calibration and zero drift. This determination was somewhat limited by the
13-minute cycle time (including a five-minute sampling time) of the AM-2 and by the need to
proceed rapidly with other test activities. Both rise and fall time were assessed for the AM-2
using the low-level mercury standard on January 17, and the rise time was assessed using the
high-concentration standard on January 23, 24, and 25. Because of the long cycle time, response
was assessed in terms of the percentage of final reading that the AM-2 achieved in a single 13-
minute cycle. For this calculation, standard gas readings were first corrected for zero gas
response before calculating the percentage change. Table 6-6 shows the data from these tests,
listing the AM-2 responses as the zero and standard gases were introduced to and removed from
the AM-2 inlet. Table 6-7 shows the results of these tests, in terms of the percentage change in
response that occurred within one AM-2 cycle.
Table 6-7 shows that for both rise and fall time, the AM-2 achieved 90 to 100% response to a
step change in concentration within one sampling/analysis cycle. Thus the 95% response time of
the AM-2 is essentially one sampling/analysis cycle.
6.8 Low-Level Response
Figure 6-3 illustrates the response of the AM-2 to low levels of mercury injected into the duct, as
described in Section 3.3.8. The dashed vertical lines indicate the time periods during which each
nominal total mercury level was introduced. Each data point represents the elemental mercury
reading of the AM-2 from one 13-minute measurement cycle. The cycle time of the AM-2 limits
the number of data points obtained at each test condition.
Figure 6-3 shows that the AM-2 responded to all mercury concentrations injected, producing an
increase above the flue gas background even with the injection of as little as 0.57 (ig/m3 of total
mercury. Thus, the primary observation from these data is that the AM-2 is sensitive enough to
detect mercury at levels below 1 (ig/m3. Since the actual flue gas mercury concentrations and
speciation were not determined, no quantitative evaluation of the AM-2 elemental mercury
response can be made. However, under the constant flue gas composition existing in this test, it
is expected that elemental mercury would be a constant fraction of the total mercury present and,
thus, that elemental and total mercury would be highly correlated. This was, in fact, observed.
When the AM-2 elemental mercury readings at each nominal total mercury level are averaged,
the coefficient of determination (r2) between the AM-2 elemental mercury readings and the
nominal total mercury was 0.997.
43
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Table 6-6. Data from Response Time Tests on the Nippon AM-2
Date
Time
Z/Sa
AM-2 Reading (pg/m3)
Rise Time
January 17
17:22
Z
0.96
17:35
s
14.4
17:49
s
15.2
January 23
18:28
z
2.69
18:41
s
53.2
18:54
s
53.0
January 24
19:24
z
2.75
19:37
s
52.6
19:51
s
57.2
January 25
15:30
z
0.88
15:43
s
52.2
15:57
s
56.7
Fall time
January 17
08:54
z
0.67
09:07
s
15.9
09:21
z
1.69
09:34
z
1.07
a Z/S = zero or standard gas reading
Table 6-7. Results of Response Time Tests: Percentage Response to Concentration Change
Within One AM-2 Cycle
Date Rise/Fall Percent Response in One Cycle
January 17 Rise 94.4
January 23 Rise 100
January 2 4 Rise 91.6
January 25 Rise 91.9
January 17 Fall 95.8
44
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3.5
4.54 ug/m3
3.0
2.5
CO
£
O)
3
2.27 ug/m3
2.0
1.13 ug/m3
E
-------
Chapter 7
Performance Summary
During the first week of verification testing, the Nippon AM-2 provided accuracy for elemental
mercury of about 14% relative to OH results, at elemental mercury levels of approximately 6 to
7 (ig/m3. In the second week of verification, the AM-2 provided relative accuracy of about 23%,
with elemental mercury levels ranging from about 5 to 25 (ig/m3. In two of the nine OH runs in
the second week, the agreement of AM-2 and OH results was unusually poor. Excluding those
two runs the AM-2 gave a relative accuracy of 12.3% in the second week of verification. The
coefficient of determination (r2) of the AM-2 and OH results was 0.878, based on the data from
both weeks of verification.
Precision of the AM-2 response was assessed in periods of stable mercury levels in the flue gas,
during the 15 OH sampling runs. The precision (as percent RSD) of the AM-2 response was
within 10% in 11 of the 15 runs and within 15% in 13 of the runs. This measured variability
includes both variability in the test facility and in the AM-2 monitor.
Calibration and zero drift were determined by repeated AM-2 analysis of zero gas and
elemental mercury standard gases. Nine such analyses in the first week of verification gave
0.56 (± 0.24) (ig/m3 and 15.5 (± 0.64) (ig/m3 for zero and standard gas, respectively. The standard
gas results equate to a 4.1% RSD in AM-2 response. Seven such analyses in the second week of
verification gave 2.12 (± 0.76) (ig/m3 and 55.3 (± 1.87) (ig/m3, for zero and standard gas,
respectively. The standard gas results equate to a 3.4% RSD in AM-2 response. The AM-2
achieved 90 to 100% response to increases and decreases in mercury concentrations within one
13-minute measurement cycle. Thus, the 95% response time is essentially one measurement
cycle.
Sampling system bias of the inlet system used with the AM-2 was determined with another
Nippon CEM that shared the common inlet system. The bias in transport of elemental mercury
through the inlet system was approximately -7%.
When added to the duct along with mercury, chlorine (and to a lesser extent hydrogen chloride)
sharply reduced the elemental mercury response of the AM-2. However, elevated levels of sulfur
dioxide, nitrogen oxides, and carbon monoxide had a minimal effect on AM-2 response, and
when these gases were present along with chlorine and hydrogen chloride, no significant
reduction in AM-2 response was observed relative to that with mercury alone.
46
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The AM-2 elemental mercury response increased above background with as little as 0.57 (ig/m3
of total mercury added to the flue gas. This result shows the capability of the AM-2 to detect
mercury at levels below 1 (ig/m3. No independent measurement of the actual elemental mercury
concentration was made for comparison to the AM-2 readings, but the AM-2 elemental mercury
readings were highly correlated with the nominal total mercury level (r2 = 0.997).
Data completeness for the AM-2 was 100%, and no repair or maintenance was needed. The unit
uses no reagents or gases other than purified air, and produces no waste.
47
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Chapter 8
References
1. Test/QA Plan for Pilot-Scale Verification of Continuous Emission Monitors for Mercury,
Battelle, Columbus, Ohio, November 30, 2000.
2. Standard Test Method for Elemental, Oxidized, Particle-Bound, and Total Mercury in Flue
Gas Generatedfrom Coal-Fired Stationary Sources (Ontario Hydro Method), American
Society for Testing and Materials, Draft Method, October 27, 1999.
3. Test Procedure for the Determination of Elemental Mercury (Fig °) Concentration from
Compressed Gas Standards Using Modified Ontario Hydro Mini-Impinger Trains, prepared
by ARCADIS Geraghty & Miller, Research Triangle Park, North Carolina, for Work
Assignment No. 2-18 of EPA Contract No. 68-C-99-201, January 11, 2001.
4. Quality Management Plan (QMP) for the E TV Advanced Monitoring Systems Pilot,
Version 2.0, U.S. EPA Environmental Technology Verification Program, Battelle,
Columbus, Ohio, October 2000.
5. Belsley, D. A., Kuh, E., and Welsch, R. E., Regression Diagnostics, John Wiley and Sons,
New York, 1980.
6. Environmental Technology Verification Report: Nippon Instruments Corporation Model
MS-l/DM-5 Mercury Continuous Emission Monitor, Battelle, Columbus, Ohio,
August 2001.
48
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