February 2007
Environmental Technology
Verification Report
THERMO ELECTRON
MERCURY FREEDOM SYSTEM
Prepared by
Battelle
Batteiie
UK Business o/Innovation
Under a cooperative agreement with
^T0 CrTr\ U.S. Environmental Protection Agency
ET1/ET1/ET1/
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February 2007
Environmental Technology Verification
Report
ETV Advanced Monitoring Systems Center
THERMO ELECTRON
MERCURY FREEDOM SYSTEM
by
Thomas Kelly
Jan Satola
Zachary Willenberg
Amy Dindal
Battelle
Columbus, Ohio 43201
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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. Mention of trade names or
commercial products does not constitute endorsement or recommendation by the EPA for use.
This report was prepared by Battelle to summarize testing supported in part by the Illinois
Department of Commerce and Economic Opportunity through the Office of Coal Development
and the Illinois Clean Coal Institute (ICCI). Neither Battelle nor any of its subcontractors nor the
Illinois Department of Commerce and Economic Opportunity, Office of Coal Development, the
ICCI, nor any person acting on behalf of either:
(a) Makes any warranty of representation, express or implied, with respect to the accuracy,
completeness, or usefulness of the information contained in this report, or that the use of
any information, apparatus, method, or process disclosed in this report may not infringe
privately-owned rights; or
(b) Assumes any liabilities with respect to the use of, or for damages resulting from the use
of, any information, apparatus, method or process disclosed in this report.
Reference herein to any specific commercial product, process, or service by trade name,
trademark, manufacturer, or otherwise, does not necessarily constitute or imply its endorsement,
recommendation, or favoring; nor do the views and opinions of authors expressed herein
necessarily state or reflect those of the Illinois Department of Commerce and Economic
Opportunity, Office of Coal Development, or the ICCI.
Notice to Journalists and Publishers: If you borrow information from any part of this
report, you must include a statement about the state of Illinois' support of the project.
11
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Foreword
The U.S. Environmental Protection Agency (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 environmental 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
assessment. Under a cooperative agreement, Battelle has received EPA funding 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/
centers/center 1 .html.
in
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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. This verification was funded in part by
the Illinois Clean Coal Institute (ICCI) under Project No. 04-1/3.2D-1; we appreciate the
involvement and support of Dr. Francois Botha, Project Manager for the ICCI. We acknowledge
the contribution of the Northern Indiana Public Service Company (NIPSCo, a NiSource
company) in hosting this verification at the R. M. Schahfer Generating Station and, in particular,
the efforts of Craig Myers, Bert Valenkamph, and Gary Logan of NIPSCo in support of the field
testing. We also thank Eric Ginsburg and William Grimley of U.S. EPA for their assistance in
setting up a Site Access Agreement among EPA, Battelle, and NiSource. Finally, we would like
to thank Robin Segall of U.S. EPA, Ernest Bouffard of the Connecticut Department of
Environmental Protection, Francois Botha of ICCI, and Craig Myers of NIPSCo for their review
of this verification report.
IV
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Contents
Page
Notice ii
Foreword iii
Acknowledgments iv
List of Abbreviations vii
Chapter 1 Background 1
Chapter 2 Technology Description 2
Chapter 3 Test Design and Procedures 4
3.1 Introduction 4
3.2 Test Facility 5
3.3 Test Procedures 5
3.3.1 Relative Accuracy 5
3.3.2 Linearity 6
3.3.3 Seven-Day Calibration Error 6
3.3.4 Cycle Time 7
3.3.5 Data Completeness 7
3.3.6 Operational Factors 7
3.4 CEM Installation 7
3.5 Verification Schedule 8
Chapter 4 Quality Assurance/Quality Control 10
4.1 OH Reference Method 10
4.1.1 OH Reproducibility 10
4.1.2 OH Blank and Spike Results 11
4.2 Audits 12
4.2.1 Performance Evaluation Audits 12
4.2.2 Technical Systems Audit 13
4.2.3 Data Quality Audit 14
4.3 QA/QC Reporting 14
4.4 Data Review 14
Chapters Statistical Methods 15
5.1 Relative Accuracy 15
5.2 Linearity 15
5.3 Seven-Day Calibration Error 16
5.4 Cycle Time 16
5.5 Data Completeness 16
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Chapter 6 Test Results 17
6.1 Relative Accuracy 18
6.2 Linearity 19
6.3 Seven-Day Calibration Error 20
6.4 Cycle Time 21
6.5 Data Completeness 22
6.6 Operational Factors 22
Chapter 7 Performance Summary 24
Chapter 8 References 25
Figures
Figure 2-1. Mercury Freedom System 2
Figure 6-1. Hgx Readings from Thermo Electron MFS During the Field Test 17
Figure 6-2. Thermo Electron MFS and OH HgT Results, July 10-13,2006 19
Tables
Table 3-1. Operating and Stack Gas Conditions at Schahfer Station Unit 17 6
Table 3-2. Weekly Test Activities During the Field Period 9
Table 3-3. Schedule of OH Method Sampling in the Week of July 10, 2006 9
Table 4-1. OH Results from July 10-13,2006, Sampling Period 11
Table 4-2. Summary of PE Audit Results 13
Table 6-1. Results from Thermo Electron MFS for Each OH Sampling Run 18
Table 6-2. Thermo Electron MFS Linearity Test Results 20
Table 6-3. Results of Zero/Calibration Stability Tests for Thermo Electron MFS 20
Table 6-4. Assessment of Cycle Time of the Thermo Electron MFS 21
Table 6-5. Thermo Electron MFS Operational Activities July 9 to 25, 2006 22
VI
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List of Abbreviations
AC
agl
AMS
ASTM
°C
CEM
CFR
EPA
ETV
°F
FGD
H2O2
H2SO4
Hg
HgCl2
Hg°
Hgox
HgT
HNO3
ICCI
KC1
klb/hr
KMnO4
LE
L/min
ug/dscm
ug/L
MFS
mL
MW
NIST
NOX
OH
ppm
PE
QA
alternating current
above ground level
Advanced Monitoring Systems
American Society for Testing and Materials
degrees Celsius
continuous emission monitor
Code of Federal Regulations
U.S. Environmental Protection Agency
Environmental Technology Verification
degrees Fahrenheit
flue gas desulfurization
hydrogen peroxide
sulfuric acid
mercury
mercuric chloride
elemental mercury
oxidized mercury
total mercury
nitric acid
Illinois Clean Coal Institute
potassium chloride
thousands of pounds per hour
potassium permanganate
linearity error
liter per minute
microgram per dry standard cubic meter
microgram per liter
Mercury Freedom System
milliliter
megawatt
National Institute of Standards and Technology
nitrogen oxides
Ontario Hydro
parts per million
performance evaluation
quality assurance
vii
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QC quality control
QMP Quality Management Plan
RA relative accuracy
%RD percent relative deviation
SC>2 sulfur dioxide
TSA technical systems audit
V volt
Vlll
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Chapter 1
Background
The U.S. Environmental Protection Agency (EPA) supports the Environmental Technology
Verification (ETV) Program to facilitate the deployment of innovative environmental
technologies through performance verification and dissemination of information. The goal of the
ETV Program is to further environmental protection by 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 testing organizations; with stakeholder groups
consisting 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 (QA) 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 the Thermo Electron Mercury Freedom System (MFS), a
continuous emissions monitor (CEM) for determining mercury in stack gas at a coal-fired power
plant. This evaluation was carried out in collaboration with the Illinois Clean Coal Institute and
with the assistance of the Northern Indiana Public Service Company.
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Chapter 2
Technology Description
The objective of the ETV AMS Center is to verify the performance characteristics of
environmental monitoring technologies for air, water, and soil. This verification report provides
results for the verification testing of the MFS. Following is a description of the MFS, based on
information provided by the vendor. The information provided below was not verified in this
test.
Designed to meet the provisions of Chapter 40 of the Code of Federal Regulations (CFR)
Parts 60 and 75 (40 CFR Parts 60 and 75), the MFS (Figure 2-1) can determine elemental (Hg°),
oxidized (Hgox), and total mercury (HgT) in exhaust
stacks of coal-fired boilers. The system uses a direct
measurement atomic fluorescence method that
precludes the use of argon tanks and gold amalgama-
tion. The system extracts a small sample flow from the
flue gas stream and immediately dilutes it inside the
probe. Any Hgox in the diluted sample is then
converted to Hg° in a dry heated converter to obtain an
HgT measurement. This diluted, converted sample is
continuously transported to the mercury analyzer in the
MFS rack where it is analyzed using atomic fluores-
cence technology developed specifically for measuring
mercury vapor concentrations on a continuous, real-
time basis. In this test, the continuous readings of the
MFS were averaged and reported at one-minute
intervals. The MFS determined only HgT for the
purposes of this test.
The MFS consists of a sampling probe with an
integrated converter, heated umbilical line, probe
controller, saturated Hg° vapor calibrator, and an
atomic fluorescence analyzer. The MFS can be audited
by introduction of mercury calibration gas standards,
which can be delivered directly to the probe inlet by the
MFS umbilical. In its rack configuration, the system is
70 inches high by 36 inches deep by 24 inches wide.
The probe box measures 34.5 inches long by 18.5 inches high by 10.5 inches wide and weighs
90 pounds. Onboard data storage capacity is
Figure 2-1. Mercury Freedom
System
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4 megabytes. Recording to a data acquisition system can be accomplished using analog output
signals, digital (RS232/485), or modbus (via an industry standard Ethernet port). The list price of
the system, as tested, excluding installation, training, and umbilical line, was $124,790.
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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
Verification of Continuous Emission Monitors (CEMs) and Sorbent-Based Samplers for Mercury
at a Coal-Fired Power Plant.^ CEMs for mercury are designed to determine total and/or
chemically speciated vapor phase mercury in combustion source emissions. Performance
requirements for mercury CEMs are contained in 40 CFR Parts 60 and 75(2) and require
assessment of the performance of newly installed mercury CEMs only for their determination of
HgT. This total is the sum of vapor-phase mercury in all chemical forms in the combustion gas,
including Hg° and Hgox (which is primarily mercuric chloride [HgCb]) vapors. In this test the
MFS was verified for its measurement of HgT.
The MFS was verified by evaluating the following parameters:
• Relative accuracy (RA)
• Linearity
Seven-day calibration error
Cycle time
• Data completeness
• Operational factors such as ease of use, maintenance and data output needs, power and other
consumables use, reliability, and operational costs.
Verification of the MFS was conducted in a field test that lasted from June 12 to July 25, 2006,
and that included two separate four-day periods of reference mercury measurements carried out
by ARCADIS Inc., under subcontract to Battelle, using American Society for Testing and
Materials (ASTM) D 6784-02, the "Ontario Hydro" (OH) method.(3) RA was determined by
comparing the MFS HgT results to simultaneous results from the OH method. Linearity was
determined based on MFS responses to Hg° standards. Calibration error was evaluated by
comparing MFS readings on mercury standard and zero gases performed once each day over a
consecutive seven-day period. Cycle time was evaluated in terms of the response of the MFS
when switching from a zero gas or upscale Hg° standard gas, supplied at the MFS probe inlet, to
sampling of stack gas. Data completeness was assessed as the percentage of maximum data
return achieved by the MFS over the test period. Operational factors were evaluated by means of
observations during testing and records of needed maintenance, vendor activities, and
expendables use.
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3.2 Test Facility
The host facility for the MFS verification was the R. M. Schahfer Generating Station, located
near Wheatfield, Indiana, approximately 20 miles south of Valparaiso, Indiana. The Schahfer
plant consists of four units (designated 14, 15, 17, and 18), with a total rated capacity of about
1,800 megawatts (MW). The MFS verification was conducted at Unit 17, which burns pulverized
Illinois sub-bituminous coal and has an electrostatic precipitator and a wet flue gas
desulfurization (FGD) unit. Unit 17 has a typical capacity of about 380 MW. The unit was
operated near this capacity for most of the test period, although the typical daily pattern of
operation was to reduce load substantially for a few hours between late evening and early
morning.
Flue gas from Unit 17 feeds into a free-standing concrete chimney with an internal liner. The top
of the stack is 499 feet above ground level (agl). Emission test ports are located at a platform
approximately 8 feet wide that encircles the outside of the stack at 370 feet agl. The stack
diameter at the platform level is 22 feet 6 inches, so the total flow area is 397.6 square feet. The
last flow disturbance is at the FGD connection to the stack liner at 128 feet agl. Thus, the
emission test ports were over 10 stack diameters downstream from the last flow disturbance and
nearly six diameters upstream from the stack exit. Four emission test ports were located at 90°
intervals around the circumference of the stack about 4 feet above the platform at 370 feet agl
and were standard 4-inch ports with #125 flanges. No traversing was done during sampling; both
the OH method and the MFS CEM sampled from a single fixed point inside the inner liner of the
stack at their respective port locations. This arrangement is justified by the absence of
stratification observed for sulfur dioxide (862) and nitrogen oxides (NOx) at this sampling
location.
Table 3-1 summarizes key operating and stack gas conditions that characterize Schahfer Unit 17
during the field period, showing the range and average values of key parameters and
constituents. Stack gas pressure was slightly positive at the sampling location.
3.3 Test Procedures
Following are the test procedures used to evaluate the MFS CEM.
3.3.1 Relative A ccuracy
The RA of the MFS was evaluated by comparing its Hgx results to simultaneous results obtained
by sampling stack gas with the OH reference method. The OH method is the currently accepted
reference method for mercury measurements in stack gas and employs dual impinger trains
sampling in parallel through a common probe to determine oxidized and elemental vapor-phase
mercury by means of appropriate chemical reagents.(3) In each of two separate weeks of the field
test period, ARCADIS conducted a series of 12 OH runs, each two hours in duration, as
described in Sections 3.5 and 4.1. The MFS was in operation at the Unit 17 test site for the
second of those OH sampling periods. The HgT concentrations in stack gas determined by the
OH reference method were compared to corresponding results from the MFS, by averaging the
successive MFS readings over the period of each OH run. A Thermo Electron vendor
representative operated the MFS during the OH sampling; however, Schahfer facility staff
operated the MFS during other periods.
5
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Table 3-1. Operating and Stack Gas Conditions at Schahfer Station Unit 17
Parameter
Unitl7Loada
Coal Feed Ratea
Temperature21
Moistureb
N0xa
S02a
HgT vaporb
Average
334 MW
297 klb/hrc
130°F
15.5%
97 ppmd
193 ppm
0.91 ug/dscme
Range
140-391
140-374
118-140
13.3-16.7
61-165
104-316
0.73-1.22
a: Values calculated from hourly data recorded routinely at the R.M. Schahfer facility, June 12 to July 25, 2006.
b: Values based on measurements made during OH reference sampling periods June 12-15 and
July 10-13, 2006.
c: klb/hr = thousands of pounds per hour.
d: ppm = parts per million.
e: ug/dscm = micrograms per dry standard cubic meter.
The OH trains were dismantled for sample recovery in the field by ARCADIS staff, and all
collected sample fractions were logged and stored for transfer to the ARCADIS analytical
laboratory. All sample handling, quality assurance/quality control (QA/QC) activities, and
mercury analyses were conducted by ARCADIS. Subsequent to mercury analysis, ARCADIS
reviewed the data and reported final mercury results from all trains in units of ug/dscm. The
results from the paired OH trains were checked relative to the duplicate precision requirement for
use of the OH data,(3'4) and qualified OH results were averaged to produce the final reference
data used for comparison to the MFS results. RA was calculated as described in Section 5.1 for
HgT based on the OH reference data, and the average of the MFS results for HgT was compared
to the corresponding average from the OH reference method.
3.3.2 Linearity
Linearity was evaluated by challenging the MFS with three concentrations of Hg° standard gases
using a calibration source built into the MFS. These standards were supplied to the MFS in non-
repetitive triplicate through the MFS's inlet filter at a rate that exceeded the MFS's inlet flow
rate. Each challenge was maintained long enough to achieve a stable response before moving to
the next challenge gas. The triplicate responses of the MFS at each challenge concentration were
averaged, and the average values were then compared to the known mercury level of the
standards. The three challenge concentrations were 3.0, 6.0, and 9.0 ug/dscm.
3.3.3 Seven-Day Calibration Error
At programmed 24-hour intervals over the period of July 17 to July 23, the MFS was challenged
with zero gas and an Hg° standard concentration of 10 ug/dscm, using the MFS calibration
source. These challenge gases were supplied through the MFS's inlet filter at a rate that exceeded
the MFS's inlet flow rate. Each such challenge was maintained long enough to achieve a stable
response. Deviation of the MFS zero and calibration readings from the expected zero or
calibration value was assessed to determine calibration error in the readings.
6
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3.3.4 Cycle Time
Cycle time was determined by monitoring the MFS readings while switching from sampling zero
gas to sampling stack gas, and from sampling an Hg° standard to sampling stack gas. The former
procedure determined the upscale response (or rise) time, and the latter the downscale response
(or fall) time. In each case, the response time was determined as the time needed to achieve 95%
of the change from one stable reading to the next.
3.3.5 Data Completeness
No additional test procedures were carried out specifically to address data completeness. This
parameter was assessed based on the overall data return relative to the total amount of data return
possible for the technology being tested.
3.3.6 Operational Factors
Operational factors such as maintenance needs, data output, consumables use, and ease of use
were evaluated based on observations by Battelle and Schahfer facility staff. A laboratory record
book was maintained at the host facility and was used to enter daily observations on these
factors. Examples of information recorded in the record books are the daily status of diagnostic
indicators for the MFS, use or replacement of any consumables, the effort or cost associated with
maintenance or repair, vendor effort (e.g., time on site) for repair or maintenance, the duration
and causes of any down time or data acquisition failure, and operator observations about ease of
use of the MFS.
3.4 CEM Installation
The MFS rack system was installed in an air-conditioned laboratory trailer placed at the base of
the Unit 17 stack. The rack components drew electrical power from two 120V/15A circuits
inside the trailer. Compressed air (110 pounds per square inch gauge) was supplied from a
compressor located near the trailer to a wall-mountable air purification panel provided by
Thermo Electron and located inside the trailer. The rack system was connected to the sampling
probe on the stack by a heated umbilical over 450 feet in length. Three 120V/30A circuits
provided power for the sampling probe, the mercury converter in the probe assembly, and the
heating of the umbilical line, respectively. Installation of the MFS was conducted by one Thermo
Electron field engineer, who trained Battelle and Schahfer facility staff in routine operation of
the MFS. That field engineer also operated the MFS during the period of OH reference method
sampling.
The MFS umbilical and needed utility supplies were in place by June 7, 2006, and the MFS rack
system arrived at the Schahfer field site on June 19. The MFS was first connected to the stack on
June 21. The slightly recessed position of the flange on the sampling port was found to prevent
the opening of doors on the CEM's sampling probe, so a port extension was installed that
allowed the doors to clear the port opening on the side of the stack. The use of this extension
caused the sampling point for the MFS probe to be 2.45 feet from the inner wall of the stack,
rather than 3.28 feet (1 meter) as prescribed in the test/QA plan.(1) Thus, the MFS sampled stack
gas from a point 10 inches closer to the stack wall than did the OH reference method. This
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difference is not expected to affect the comparison of CEM and OH data in Section 6.1 because
of the lack of stratification observed in the Unit 17 stack for other gases (SO2 and NOX).
Several problems were encountered with the MFS once it was installed at Schahfer Unit 17,
including rapidly dropping mercury readings that were ascribed by the vendor to inlet
contamination; improper connection of the rack system computer to the MFS; improper
orientation of valves in the probe and MFS rack system; sampling flow rate set excessively high
for the Unit 17 stack conditions; inadequate performance of inertial filter material in the
sampling probe; and failure of a probe heater control board in the MFS rack system. Thermo
Environmental representatives worked with the assistance of Schahfer facility staff to address
these problems; however, proper operation of the MFS was not achieved until July 9.
As noted below, the field verification began with collection of a series of 12 OH samples from
June 12 to!5. The MFS system was not on site for that set of OH runs and was not fully
operational until July 9, shortly before a second set of 12 OH sampling runs was conducted on
July 10 to 13. The MFS then continued to monitor stack gas continuously until the end of the
field test on July 25.
3.5 Verification Schedule
The MFS was verified between July 9 and July 25, 2006, in a portion of a field test that lasted
from June 12 to July 25 and in which two sorbent-based mercury sampling systems and one
other mercury CEM were also evaluated. The MFS became fully operational for sampling stack
gas at Unit 17 on July 9 and was shut down on July 25, 2006. Table 3-2 shows the weekly
activities relevant to the MFS verification that were conducted prior to and during the field
period.
Table 3-3 shows the actual schedule of OH reference method sampling completed by ARCADIS
in the week of July 10. The OH sampling proceeded efficiently, with three runs conducted on
each of four successive days. In all cases, Thermo Electron personnel and other participating
vendors were informed of the planned start time of each OH run and, in few instances, the start
time of a run was delayed slightly to assure that the technologies being tested were fully ready to
obtain data during the OH run. All OH runs were of exactly two hours duration, and Thermo
Electron personnel were notified as the ending time of each run approached.
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Table 3-2. Weekly Test Activities During the Field Period
Week of Test Activity
May 15 Battelle trailer arrived at Schahfer facility
May 22 Electric power and other utilities established at Schahfer facility
May 29 No activity related to MFS
June 5 MFS umbilical installed at Unit 17 stack
June 12 First OH reference method sampling period
June 19 MFS rack components and probe arrive at test site
June 26 MFS trial operation and troubleshooting
July 3 MFS trial operation and troubleshooting
July 10 MFS fully operational; Second OH reference method sampling period
July 17 Routine operation
July 24 Routine operation concluded; MFS shut down and removed from Battelle
trailer
Table 3-3. Schedule of OH Method Sampling in the Week of July 10, 2006
Run Number
1
2
3
4
5
6
7
8
9
10
11
12
Date
7/10/06
7/10/06
7/10/06
7/1 1/06
7/1 1/06
7/1 1/06
7/12/06
7/12/06
7/12/06
7/13/06
7/13/06
7/13/06
Start Time
9:00
11:50
14:55
8:30
11:15
14:00
8:30
11:40
14:15
8:20
11:10
13:45
End Time
11:00
13:50
16:55
10:30
13:15
16:00
10:30
13:40
16:15
10:20
13:10
15:45
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Chapter 4
Quality Assurance/Quality Control
QA/QC procedures were performed in accordance with the quality management plan (QMP) for
the AMS Center(5) and the test/QA plan for this verification test.(1) QA/QC procedures and
results are described below.
One deviation from the test/QA plan occurred due to the inability to position the MFS sampling
point at 1 meter inside the inner wall of the stack (see Section 3.4). A deviation form was
prepared and approved noting this occurrence.
4.1 OH Reference Method
This verification test included a comparison of the MFS results to those of the OH reference
method for flue gas mercury.(3'4) The quality of the reference measurements was assured by
adherence to the requirements of the OH method, including requirements for solution and field
blanks, spiked samples, and continuing calibration standards. All OH reference measurements
were made with paired trains, and the percent relative deviation (%RD = the difference between
the paired train results divided by the sum of those results, expressed as a percentage) of each
data pair was required to be < 10% (at mercury levels >1.0 ug/dscm) or < 20% (at mercury levels
< 1.0 ug/dscm).(4) Data not meeting this criterion were excluded from comparison with the MFS
results. The following sections present key data quality results from the OH method.
4.1.1 OH Reproducibitity
The mercury results of the OH stack gas samples are shown in Table 4-1, for the July 10-13
period of OH method sampling. This table indicates the OH run number and lists the average
vapor phase Hgox, Hg°, and HgT results from the paired OH trains in each run and the %RD of
each pair of results. All mercury results are in ug/dscm, i.e., adjusted to 20°C (68°F) and one
atmosphere pressure.
Inspection of Table 4-1 shows that HgT in the Unit 17 stack ranged from 0.787 to 1.215 ug/dscm
in the OH runs conducted in the July 10-13 period. The average HgT value in this period was
1.008 ug/dscm (note that one OH result for HgT is excluded from this average because of
inadequate dual train precision, as described below). Hg° comprised the great majority of the
Hgx, consistent with the scrubbing of the Schahfer Unit 17 flue gas. Hgox never exceeded about
0.09 ug/dscm, and was typically about 5% of the HgT.
10
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Table 4-1. OH Results from July 10-13, 2006, Sampling Period
Mercury Concentration (ug/dscm) and %RD of Paired Train Results3
OH Run
1
2
3
4
5
6
7
8
9
10
11
12
Hgox
0.033
0.037
0.040
0.066
0.029
0.038
0.028
0.084
0.090
0.093
0.092
0.037
%RD
10.1
2.9
3.7
52.3
11.6
2.0
5.7
7.2
6.3
0.6
0.9
22.7
Hg°
0.902
0.823
0.929
0.886
0.757
1.018
1.055
0.997
1.126
0.982
1.014
1.015
%RD
0.8
1.4
1.1
1.4
0.3
6.5
1.2
12.6
0.7
0.1
2.0
0.6
HgT
0.935
0.860
0.969
0.952
0.787
1.056
1.083
1.081b
1.215
1.074
1.107
1.053
%RD
0.4
1.2
0.9
4.9
0.1
6.4
1.3
11.0
0.2
0.1
1.8
0.2
a: %RD = difference between paired train results divided by sum of paired train results.
b: This data point excluded from calculation of RA because %RD value exceeds acceptance criterion.
The %RD values in Table 4-1 show generally close agreement between the paired OH train
results for all three mercury fractions. The %RD values are less than about 6.5% in almost all
runs for both Hg° and HgT. The only exceptions were the results for OH Run #8. The HgT result
from that run is excluded from calculations of RA because the %RD value is outside the 10%
criterion for values >1.0 ug/dscm. The %RD values for Hgox are slightly higher than those for
HgT and Hg°, presumably due to the low Hgox concentrations, with two %RD values exceeding
20%.
4.1.2 OH Blank and Spike Results
Analyses were conducted on 10 total samples collected at the Schahfer site from the blank
reagents used in the OH method in the July 10-13 period. Only two of those samples showed
detectable mercury, with concentrations of 0.003 and 0.006 microgram per liter (ug/L),
respectively. This blank reagent concentration is negligible in comparison to the mercury in
impinger solutions recovered from trains after stack sampling. Those recovered sample
concentrations were typically about 0.1 ug/L, 0.2 ug/L, and 4 ug/L in potassium chloride (KC1)
solution, hydrogen peroxide (H2O2) solution, and potassium permanganate (KMnO/t) solution,
respectively.
Blank OH sampling trains were prepared and taken to the sampling location on the Unit 17 stack
on three occasions in each week of OH sampling, and were then returned for sample recovery
without exposure to stack gas. These blank OH trains provide additional assurance of the quality
of the train preparation and recovery steps. For the July 10-13 sampling period, the total
amounts of mercury recovered from the three blank trains range from 0.193 to 0.250 ug,
equivalent to less than 10% of the typical total amount of mercury recovered from a train after
11
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stack sampling at the Schahfer plant. Those blank train results correspond to stack gas mercury
concentrations of less than 0.1 ug/dscm under typical sampling conditions in this verification.
All initial and continuing blank and calibration values from laboratory analysis of the OH
samples met the requirements of the OH method. The recovery of mercury spiked into each
reagent solution recovered from blank and sampled OH trains was also evaluated during
laboratory analysis. Those spike recoveries ranged from 88 to 117% and averaged 100%. The
recovery of mercury spiked into blank train samples as part of the performance evaluation (PE)
audit also met the prescribed criteria, as described in Section 4.2.1.
4.2 Audits
Three types of audits were performed during the verification test: a PE audit of the reference
method, a technical systems audit (TSA) of the verification test procedures, and a data quality
audit. Audit procedures are described further below.
4.2.1 Performance Evaluation Audits
PE audits of the OH method were carried out through procedures implemented at the Schahfer
plant during the field period. Table 4-2 summarizes the procedures and results of the PE audits of
the OH reference method, showing the parameter audited, the date of the audit, the OH and
reference values, the observed agreement, and the target agreement. The OH method
incorporates dual sampling trains, and the equipment used by ARCADIS to carry out the OH
sampling included dual Model 522 Source Sampler meter boxes (Apex Instruments, Fuquay-
Varina, North Carolina) designated by their serial numbers as #2007 and #2008. As a result, for
some parameters, Table 4-2 includes results for both meter boxes or for both of the dual OH
trains.
Four PE audits were conducted:
• A Fluke Model 52 II digital thermometer (Serial No. 80730162) was used to audit the probe
temperature measurements made by the #2007 meter box and the stack temperature
measurements made by the #2008 meter box. For this comparison, the appropriate
thermocouple was disconnected from the meter box and connected to the Fluke thermometer.
• A BIOS International Corporation DryCal National Institute of Standards and Technology-
(NIST)-traceable flow measurement standard (Model DC2-B, Serial No. 103777, vendor-
calibrated on May 9, 2006) was used to audit the sample gas flow rate with each of the two
OH meter boxes.
• A set of weights (Rice Lake Weight Set, Serial No. 1JXA) calibrated to ASTM Class 3
standards was used to audit the electronic balance (AND FP-6000, Serial No. 6402118) used
for weighing the OH method impingers.
• Recovery of mercury from OH trains was audited by spiking impingers containing KC1,
H2O2/nitric acid (HNOs), and KMnOVsulfuric acid (H2SO4) reagents in two blank OH
impinger trains, with 1 milliliter (mL) of a prepared mercury solution, in each of the two
separate periods of OH sampling. The mercury spiking solution was 2.5 ug/mL Hg in 1%
12
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and was prepared by dilution of a NIST-traceable 1,000-ppm (i.e., 1,000-ug/mL)
standard (Aa34n-l, Accustandards, Inc.). In the first week of OH sampling, Impingers 2, 4,
and 5 of Blank Trains 8L and 8R were spiked; and, in the final week of OH sampling,
Impingers 2, 4, and 6 of Blank Trains 7L and 7R were spiked.
Table 4-2 shows that all the PE audit results were within the target tolerances set in the test/QA
plan.(1)
Table 4-2. Summary of PE Audit Results
Parameter
OH temperature
measurement
OH sample flow
measurement
Impinger weighing
Mercury spike
recovery
Date
6/14/06
probe T
stack T
7/11/06
6/14/06
6/14/06
train 8L
imp 2
imp 4
imp 5
train 8R
imp 2
imp 4
imp 5
7/12/06
train 7L
imp 2
imp 4
imp 6
train 7R
imp 2
imp 4
imp 6
OH Result
228°Fa
127°Fb
15.02L/mina
14.58 L/minb
199.72
499.27
2.48 ug
2.02 ug
2.08 ug
2.47 ug
1.97ug
2.10ug
2.24 ug
2.12ug
2.38 ug
2.27 ug
2.33 ug
2.39 ug
Reference
Value
230°F
129°F
14.56 L/min
14.35 L/min
200 grams
500 grams
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
2.5 ug
Agreement
with
Standard
0.29%
0.31%
3.2%
1.6%
0.14%
0.15%
0.8%
19.2%
16.8%
1.2%
21.2%
16.0%
10.4%
15.2%
4.8%
9.2%
6.8%
4.4%
Target
Agreement
2% absolute T
5%
Greater of 1%
or 0.5 gram
25%
25%
25%
25%
25%
25%
25%
25%
25%
25%
25%
25%
a: #2007 meter box
b: #2008 meter box.
L/min = liters per minute; T = temperature; imp
= impinger.
4.2.2 Technical Systems A udit
A Battelle Quality Management representative conducted a TSA at the Schahfer test site on
June 14 to ensure that the verification test was being conducted in accordance with the test/QA
plan(1) and the AMS Center QMP.(5) As part of the TSA, test procedures were compared to those
specified in the test/QA plan,(1) and data acquisition and handling procedures, as well as the
reference standards and method, were reviewed. The Quality Management representative
13
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observed OH method sampling and sample recovery processes, interviewed ARCADIS
personnel, and observed the PE audit procedures noted above, except for the OH sample flow
and second OH train spiking audits, which were conducted at a later date. Observations and
findings from the TSA were documented and submitted to the Battelle Verification Test
Coordinator for response. None of the findings of the TSA at the Schahfer site required
corrective action. In addition, an internal TSA was conducted in the laboratory charged with
analyzing the OH samples. This TSA was conducted by the ARCADIS independent QA Officer
in the laboratory on-site at EPA in Research Triangle Park, North Carolina, on July 19 and
July 27, 2006. None of the findings of this laboratory TSA required corrective action. Records
from both TSA efforts are permanently stored with the Battelle Quality Manager.
4.2.3 Data Quality Audit
At least 10% of the data acquired during the verification test were audited. Battelle's Quality
Manager traced the data from the initial acquisition, through reduction and statistical analysis, to
final reporting to ensure the integrity of the reported results. All calculations performed on the
data undergoing the audit were checked.
4.3 QA/QC Reporting
Each audit was documented in accordance with Sections 3.3.4 and 3.3.5 of the QMP for the ETV
AMS Center.(5) Once the audit reports were prepared, the Battelle Verification Test Coordinator
ensured that a response was provided for each adverse finding or potential problem and imple-
mented any necessary follow-up corrective action. The Battelle Quality Manager ensured that
follow-up corrective action was taken. The results of the TSA were submitted to the EPA.
4.4 Data Review
Records generated in the verification test received a one-over-one review before these records
were used to calculate, evaluate, or report verification results. Data were reviewed by a Battelle
technical staff member involved in the verification test. The person performing the review added
his/her initials and the date to a hard copy of the record being reviewed.
14
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Chapter 5
Statistical Methods
The statistical methods used to evaluate the performance factors listed in Section 3.1 are
presented in this chapter. Qualitative observations were also used to evaluate verification test
data.
5.1 Relative Accuracy
The RA of the MFS for Hgx determination with respect to the OH reference method results was
assessed as a percentage, using Equation 1:
^
r> A * fi ^. i C\C\0/ /i \
KA — = X 1UU /o n )
X
where Prefers to the difference between the OH reference mercury concentration and the
average MFS reading over the OH sampling period, and x corresponds to the OH reference
mercury concentration. Sd denotes the sample standard deviation of the differences, while fn-i is
the t value for the 100(1 - a)th percentile of the distribution with n-1 degrees of freedom. The RA
was determined for an a value of 0.025 (i.e., 97.5% confidence level, one-tailed). All paired OH
data meeting the method quality criteria were eligible for inclusion in the calculation of RA. An
RA of less than 20% is considered acceptable.^ Alternatively, when the mean reference mercury
level is less than 5.0 ug/dscm (as in this test), agreement of the overall mean MFS value within
1.0 ug/dscm of the mean OH value is also considered acceptable.(2)
5.2 Linearity
The linearity of the MFS response was assessed by comparing its responses to the Hg° standard
concentrations, using Equation 2:
R-A (^
LE = xlOO (2)
R
where LE is the linearity error at each concentration, R is the reference mercury concentration
supplied to the MFS, and A is the average of the triplicate readings at each concentration. LE
within 10% is acceptable.(2)
15
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5.3 Seven-Day Calibration Error
The assessment of calibration error was based on the difference between the MFS responses and
the known mercury content of the zero or standard gas. Calibration error was calculated from the
MFS responses to both the zero and calibration gases for each of the seven consecutive days of
this test. Specifically, calibration error was calculated using Equation 3:
R-A ,_,
CE = xlOO (3)
S
where CE is the calibration error as a percentage of the MFS span value, R is the reference
mercury concentration supplied to the CEM, A is the MFS response to the reference gas, and S is
the span value of the instrument. Acceptable calibration error is within 5%.(2) However, for this
verification, a span value of 10 ug/dscm was assumed and, therefore, the secondary acceptance
criterion of 1.0 jig/dscm (10% of span) applies.(2) The absolute value of the differences (R - A)
were also reported.
5.4 Cycle Time
The upscale and downscale cycle times (essentially the rise and fall times) of the MFS response
were determined as the elapsed time needed to achieve 95% of the final stable reading after
switching from zero gas to stack gas and from a high mercury standard to stack gas, respectively.
The slower (i.e., longer) of the two response times was reported as the cycle time of the MFS.
Cycle times not exceeding 15 minutes are acceptable under Part 75.(2)
5.5 Data Completeness
Data completeness was calculated as the percentage of the total possible data return that was
achieved by the MFS over the entire field period. This calculation used the total hours of data
recorded divided by the total hours of data in the entire field period. The field period began at the
start of the first OH method run on June 12 and ended at the shutdown of the CEM on July 25.
For this calculation, no distinction was made between data recorded during stack gas monitoring
and that recorded during calibration or zeroing, or in performance of linearity, cycle time, and
seven-day calibration error testing. The causes of any substantial incompleteness of data were
established from operator observations or vendor records.
16
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Chapter 6
Test Results
The results of the verification tests of the Thermo Electron MFS are presented below for each of
the performance parameters. To illustrate the overall results for this CEM, Figure 6-1 shows all
of the MFS CEM's stack gas Hgx readings for its period of operation, which spanned
approximately 16 days, from July 9 (designated as Day 27) to July 25 (Day 44) of the field
period. The x-axis label in Figure 6-1 defines the July 10 to 13 OH sampling period as days 28 to
31. Figure 6-1 shows that the Hgx readings of the MFS were usually between about 0.8 and
1.7 ug/dscm. A frequent daily pattern of Hgx readings is evident, in that lower Hgx values were
reported in the early morning hours when the load was reduced on Unit 17. The gap in data on
Days 31 through 34 is apparently caused by a failure to record those data, as no data from that
time period were found in the data file downloaded from the MFS at the end of the field period.
Thermo CEM HgT
o
27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44
Time in Days (Days 28 - 31 span OH2,10-13-July 2006)
Figure 6-1. HgT Readings from Thermo Electron MFS During the Field Test
17
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6.1 Relative Accuracy
The RA of the MFS with respect to the OH results for HgT was calculated using Equation 1 in
Chapter 5. Table 6-1 lists the MFS results for those time periods corresponding to each of the
OH sampling runs (see Table 4-1). The MFS HgT results in Table 6-1 are each the average of
120 one-minute average readings, obtained in continuous monitoring over the 2-hour period of
each OH run. The MFS and OH results for HgT are shown graphically in Figure 6-2 for the
July 10-13 sample set. Note that the OH result for HgT from run #8 in the July 10-13 sampling
period was excluded from the calculation of RA (and from Figure 6-2) because the %RD value
exceeded the acceptance criterion (see Section 4.1.1).
Table 6-1. Results from Thermo Electron MFS for Each OH Sampling Run
Date
7/10/2006
7/10/2006
7/10/2006
7/1 1/2006
7/1 1/2006
7/1 1/2006
7/12/2006
7/12/2006
7/12/2006
7/13/2006
7/13/2006
7/13/2006
OH
Run
1
2
3
4
5
6
7
8
9
10
11
12
MFS Hgx
(jig/dscm)
1.023
1.038
1.071
1.004
0.955
0.971
1.074
1.071
1.052
1.236
1.273
1.294
Based on the HgT data in Tables 4-1 and 6-1, and shown in Figure 6-2, the RA of the MFS for
HgT determination was calculated to be 16.4%.
In addition to the calculation of RA, the mean values of HgT from the OH method and the MFS
CEM were compared. The data from run #8 were excluded from this comparison as well. The
mean HgT value from the other 11 OH results was 1.008 ug/dscm, and the mean MFS HgT result
for those same 11 runs was 1.090 ug/dscm, a difference of 0.082 ug/dscm. This difference is
well within the 1.0 ug/dscm acceptable difference from the mean OH value.(2)
18
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1.3 -
1.2 -
1.1 -
o
0.9 -
0.8 -
0.7 -
0.6 -
0.3
0.1
567
OH2 Run Number
10
12
Figure 6-2. Thermo Electron MFS and OH HgT Results, July 10-13, 2006
6.2 Linearity
The linearity of the Thermo Electron MFS was evaluated over a concentration range of 3 to
9 jig/dscm. Table 6-2 shows the results of the linearity test. Shown in the table are the date of
the test, the Hg° standard concentrations, the triplicate MFS responses to each mercury standard,
the mean of the triplicate sets of responses, the difference between that mean and the standard
value, and the resulting LE, calculated using Equation 2 (Section 5.2). As shown in Table 6-2,
the LE of the MFS CEM was within 7.2% at the lowest concentration point and within 2.7% at
the higher two points.
19
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Table 6-2. Thermo Electron MFS Linearity Test Results
Linearity Test
Date
July 25
Hg Standard
(jig/dscm)
3.00
6.00
9.00
MFS
Responses
(ug/dscm)
3.24
3.17
3.24
6.20
6.13
6.15
9.20
9.24
9.25
MFS
Mean
(ug/dscm)
3.22
6.16
9.23
Difference
(jig/dscm)
0.22
0.16
0.23
LE
(%)
7.2
2.7
2.6
6.3 Seven-Day Calibration Error
Calibration error of the Thermo Electron MFS CEM was determined based on zero and
calibration responses obtained on each of seven consecutive days. Table 6-3 summarizes the
results, listing the zero and calibration responses and the resulting calibration error, calculated
according to Equation 3 (Section 5.3) and expressed as a percentage of the 10 ug/dscm span
value. Table 6-3 shows that the MFS exhibited zero readings ranging from 0.024 to
0.027 ug/dscm (up to 0.27% of span), and differences from the 10 ug/dscm standard of up to
0.13 ug/dscm (up to 1.3% of span). All the MFS calibration results are well within the 5% of
span acceptance criterion and the alternate 1 ug/dscm acceptance criterion for a span range of
10 ug/dscm.(2)
Table 6-3. Results of Zero/Calibration Stability Tests for Thermo Electron MFS
Date
July 17
July 18
July 19
July 20
July 21
July 22
July 23
Zero
Readings
(jig/dscm)
0.025
0.025
0.024
0.026
0.027
0.026
0.027
Difference
from
Standard8
(jig/dscm)
0.025
0.025
0.024
0.026
0.027
0.026
0.027
Zero Error
(%)b
0.25
0.25
0.24
0.26
0.27
0.26
0.27
Calibration
Readings
(jig/dscm)
10.06
10.00
10.04
10.01
10.07
10.09
10.13
Difference
from
Standard0
(jig/dscm)
0.06
0.00
0.04
0.01
0.07
0.09
0.13
Calibration
Error
(%)b
0.6
0.0
0.4
0.1
0.7
0.9
1.3
a: Relative to standard concentration of zero.
b: Relative to span value of 10 ug/dscm.
c: Relative to standard concentration of 10.00 ug/dscm.
20
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6.4 Cycle Time
The cycle time of the Thermo Electron MFS CEM was assessed by switching the CEM between
sampling calibration or zero gas and sampling stack gas. This assessment was somewhat
complicated by the integrated sampling mode of the MFS, which produced new mercury
readings at one-minute intervals, and by noise in the CEM readings at the low stack gas mercury
levels observed. However, data were sufficient to allow an estimate of cycle time. Table 6-4
presents the data from periods used to assess the cycle time of the MFS, showing the date, time,
and value of the MFS readings in ug/dscm; the readings chosen as the initial and final readings,
and readings near the 95% change level; and the estimate of cycle time (either rise time from
zero gas to stack gas or fall time from calibration gas to stack gas).
Table 6-4. Assessment of Cycle Time of the Thermo Electron MFS
Date
July 25
July 25
Time
17:17
17:18
17:19
17:20
17:21
17:22
17:23
17:24
17:25
17:26
17:50
17:51
17:52
17:53
17:54
17:55
17:56
17:57
MFS
Reading
(ug/dscm)
0.10
0.10
0.08
0.51
1.89
2.30
1.82
1.71
1.64
1.72
10.70
10.64
6.49
3.17
2.29
1.93
1.81
1.80
Comments
Initial reading
99.4% increase
95% increase
Final reading
Initial reading
94.5% decrease
98.5% decrease
Final reading
Cycle Time
Estimate
Rise time 5 to
6 minutes
Fall time 3 to
4 minutes
Table 6-4 shows that the MFS rise time was estimated to be 5 to 6 minutes, and the fall time as
3 to 4 minutes. The MFS reading initially overshot the stack gas HgT level upon switching from
zero gas to stack gas (see readings in Table 6-4 at 17:17 to 17:26), so the readings actually
settled toward the stable stack gas value rather than increasing to it. This behavior is apparently
an artifact of the switching of gases supplied to the MFS probe. The longer of the two response
times, i.e., 5 to 6 minutes, is the cycle time of the MFS.
21
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6.5 Data Completeness
The total duration of the field test was from the start of the first OH sampling run on June 12 to
the shutdown of the CEMs on July 25, a total of 43.4 days. The Thermo Electron MFS was
operational in the field for only 16.8 days, from July 9 to July 25, or 38.7% of the entire field
period. Table 6-5 shows a breakdown of the operating activities of the MFS over those
16.8 operational days.
Table 6-5 shows that the 16.8 days of operation of the Thermo Electron MFS CEM consisted of
approximately 1.2 days of calibration, zeroing, and other programmed QC procedures; 0.1 days
conducting or re-stabilizing after programmed filter blowback; and 15.4 days of routine
monitoring of stack gas mercury. Unfortunately, for 3.3 days of that routine monitoring (19.7%
of the Thermo Electron MFS operational time), data were apparently not recorded by the MFS
CEM, so only 12.1 days of actual stack gas data were recovered from the MFS CEM. The great
majority of this data loss occurred from July 13 to 17, as shown in Figure 6-1.
Table 6-5. Thermo Electron MFS Operational Activities July 9 to 25, 2006
Activity
Stack Gas Monitoring
Monitoring Data Not Recorded
Filter Blowback
Calibration/Zeroing/Other Checks
Totals
Number of Measurement
Intervals3
17,401
4,757
191
1,782
24,131
Days
12.1
3.3
0.1
1.2
16.8
Percent of
Time
72.1%
19.7%
0.8%
7.4%
100%
a: Each measurement was a one-minute average.
6.6 Operational Factors
The Thermo Electron MFS used only electrical power and facility compressed air as
consumables. The electrical power needs consisted of two 15A circuits to run the rack system in
the trailer, and three other 30A circuits for the umbilical, the stack sampling probe, and the
mercury converter, respectively. The MFS used software that controlled all monitoring,
calibration, and data acquisition functions and displayed the current mercury reading on the front
panel of the mercury analyzer. The software is fully accessible by means of an analog phone line
through a modem built into the MFS's computer, and Thermo Electron staff frequently used this
means of access to the MFS. The software automatically saved data records, but did not
automatically save a data file over daily or other time periods. Instead, the operator entered the
range of records (date, time) to be downloaded, and the software compiled those records into a
data file. This operation was carried out twice during the field period, on June 13 and July 25.
Data recovery was incomplete in the second download, as about three days of data were
apparently unrecorded by the Thermo Electron MFS. The data file produced by this download
process was also hard to interpret, as MFS operations such as zeroes, calibrations, filter
22
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blowback, etc., were not clearly identified. Instead, Battelle staff were provided with a small
Excel® file showing the alphanumeric code associated with each such operation, so that the data
file could be interpreted. Battelle staff wrote a program to automatically decipher the codes in the
MFS data file and insert identifiers for the operations. The Thermo Electron field engineer
indicated that an update to the MFS software will be made to automate identification of each
MFS reading.
The Thermo Electron MFS did not arrive at the Schahfer Unit 17 site until June 19, due to
problems found in the vendor's pre-test checkout process, and continued to have problems once
installed in the field. On June 22 the Thermo Electron field engineer suspected that the inertial
particle filter in the sampling probe was removing mercury from the stack gas sample, so the
probe was brought to ground level for cleaning. However, thorough cleaning of the probe on
June 22 and 23 caused no improvement in MFS performance. Over the next several days (until a
Thermo Electron engineer arrived on July 6), Schahfer facility staff spent extensive time with
Thermo Electron representatives by telephone troubleshooting several alarms in the MFS,
including low dilution flow; low filter dilution factor; pressure, flow, and span failure; high
probe temperature; and low eductor pressure. During this period, a valve was found to be in the
wrong position in the MFS sampling probe, and an improper connection was found between the
MFS and the laptop computer in the rack. On July 6 there was no communication with the MFS
probe controller, and over the next two days the Thermo Electron engineer worked with Schahfer
staff to rework the probe, check for plugging, install a new circuit board, and reestablish
communication with the probe. These staff cleaned the probe and found that the stack gas sample
flow rate was set at 20 L/min when a flow of about 2 L/min would be appropriate for a wet stack
such as at Unit 17. The sample flow was reduced to 2 L/min, and three critical orifices in the
probe were cleaned and replaced. At this time, the Thermo Electron engineer also replaced a
control board in the probe controller in the rack system and corrected a check valve in the rack
system that was installed backwards. By July 9 the MFS was operating correctly; on the morning
of July 10, the MFS was declared ready by Thermo Electron for monitoring in comparison with
the OH method, and for the next several days the CEM operated apparently without problems
and produced consistent readings of stack gas mercury. However, the CEM probe temperature
and converter temperature were found to be out of normal range by the early morning of July 20,
presumably due to a bad control board. The Thermo Electron engineer also reported difficulties
during final calibration checks at the end of the test, on July 25, and suspected problems in the
filter or probe.
Thermo Electron representatives spent about 11 man-days at the Schahfer Unit 17 test site during
the field test and controlled the MFS remotely via modem in other periods. In addition, several
hours were spent over multiple days in telephone conversations between Thermo Electron and
Schahfer facility staff, troubleshooting the behavior of the CEM.
23
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Chapter 7
Performance Summary
The RA of the Thermo Electron MFS was 16.4% for Hgx, based on comparison to 11 OH
reference results. The overall average value from that set of OH data was 1.008 ug/dscm,
respectively, whereas that from the MFS was 1.090 ug/dscm, a difference of 0.082 ug/dscm.
The LE of the MFS was 2.6 to 7.2% when tested over the range of 3 to 9 ug/dscm.
The seven-day calibration error of the MFS was evaluated with zero gas and with a calibration
gas of 10 ug/dscm Hg°. Error in zero readings ranged from 0.24 to 0.27% of span, and error in
calibration gas readings from 0.0 to 1.3% of span, in both cases relative to an assumed
10 ug/dscm span value.
Cycle time of the MFS was estimated to be 5 to 6 minutes, based on readings during switching
from zero gas to sampling of stack gas. The MFS recorded a mercury reading every minute, so
the cycle time was estimated as a multiple of this integration time.
Data completeness for the MFS was 38.7%, based on its operation for 16.8 days over the
approximately six-week field test. Considering only those 16.8 days on which the MFS was fully
operational, 12.1 days of stack gas data were recovered, 1.2 days were spent in calibration/
zeroing/other instrument checks, and 0.1 day was spent in conducting or recovering from filter
blowback. Another 3.3 days of routine stack gas monitoring proceeded without apparent
problems but produced no recorded mercury data.
The MFS required 120V AC power and connection to facility compressed air. The MFS is
controlled by software that can be accessed locally or remotely and that provides rapid control of
all instrument operations and information on mercury results and instrument functions. Zeroing,
calibrations, and other operations were not clearly identified in the data files that resulted from
this software. It was necessary to decipher the data files, by means of a separate code file
provided by Thermo Electron, to identify such operations in the data. The MFS suffered from
several problems that delayed its arrival in the field and limited its operational time once there.
Problems included inadequate performance of the inertial probe material, failure of probe heating
and control circuit boards, improperly installed valves, excessively high sample flow for the
stack conditions, and failure of communication with the MFS on-board computer.
The cost of the Thermo Electron MFS as tested was approximately $124,790, excluding the
umbilical line, installation, and training.
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Chapter 8
References
1. Test/QA Plan for Verification of Continuous Emission Monitors and Sorbent-Based
Samplers for Mercury at a Coal-Fired Power Plant, Battelle, Columbus, Ohio, May 18,
2006.
2. Code of Federal Regulations, 40 CFR Part 75, including Appendices A through K, and
Part 60, July 2005.
3. Standard Test Method for Elemental, Oxidized, Particle-Bound and Total Mercury in Flue
Gas Generated from Coal-fired Stationary Sources (Ontario Hydro Method)., ASTM D
6784-02, American Society for Testing and Materials, West Conshohocken, PA, June 2002.
4. Performance Specification 12A - Specifications and Test Procedures for Total Vapor Phase
Mercury Continuous Emission Monitoring Systems in Stationary Sources, 40 CFR Part 60
Appendix B, July 2005.
5. Quality Management Plan (QMP) for the ETV Advanced Monitoring Systems Center,
Version 6.0, U.S. EPA Environmental Technology Verification Program, Battelle,
Columbus, Ohio, November 2005.
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