THE ENVIRONMENTAL TECHNOLOGY VERIFICATION PROGRAM
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Illinois Clean Coal Institute
ETV Joint Verification Statement
TECHNOLOGY TYPE: Mercury Emissions Monitor
APPLICATION: Monitoring of Flue Gas Mercury
TECHNOLOGY
NAME: Thermo Electron Mercury Freedom System
COMPANY: Thermo Electron Corporation
ADDRESS: 81 Wyman Street PHONE: (781) 622-1000
Waltham, MA 02454 FAX: (781) 622-1207
WEB SITE: www.thermo.com
E-MAIL:
The U.S. Environmental Protection Agency (EPA) has established 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 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. Information and ETV documents are available at www.epa.gov/etv.
ETV works in partnership with recognized standards and testing organizations, with stakeholder groups
(consisting of buyers, vendor organizations, and permitters), and with 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 Advanced Monitoring Systems (AMS) Center, one of six technology areas under ETV, is operated by
Battelle in cooperation with EPA's National Exposure Research Laboratory. In collaboration with the Illinois
Clean Coal Institute, and with assistance from the Northern Indiana Public Service Company, the AMS Center
evaluated the performance of the Thermo Electron Mercury Freedom System (MFS) for determining mercury in
stack gas at a coal-fired power plant. This verification statement provides a summary of the test results.
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VERIFICATION TEST DESCRIPTION
The performance of the MFS was evaluated in terms of relative accuracy (RA), linearity, seven-day calibration
error, cycle time, data completeness, and operational factors (ease of use, maintenance and data output needs,
power and other consumables use, reliability, and operational costs). RA was determined according to Equation
A-10 of Chapter 40 of the Code of Federal Regulations Part 75 (40 CFR Part 75) Appendix A, by comparing
MFS vapor-phase total mercury (HgT) results to simultaneous results from American Society for Testing and
Materials D 6784-02, the "Ontario Hydro" (OH) method. 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
elemental mercury (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.
The MFS was verified at Unit 17 of the R.M. Schahfer Generating Station, located near Wheatfield, Indiana, in
part of a field test that took place between June 12 and July 25, 2006. Unit 17 burns pulverized Illinois sub-
bituminous coal and has an electrostatic precipitator and a wet flue gas desulfurization unit. During the period
of operation of the MFS, twelve successive OH method runs, each of 2 hours duration, were conducted on the
Unit 17 stack using paired OH trains. Those reference samples were collected and analyzed to determine Hg°
and oxidized mercury (Hg0x), the sum of which is HgT.
QA oversight of verification testing was provided by Battelle and EPA. Battelle QA staff conducted a technical
systems audit, a performance evaluation audit, and a data quality audit of 10% of the test data.
This verification statement, the full report on which it is based, and the test/QA plan for this verification test are
all available atwww.epa.gov/etv/centers/centerl.html.
TECHNOLOGY DESCRIPTION
The following description of the MFS is based on information provided by the vendor. The information
provided below was not verified in this test.
Designed to meet the provisions of 40 CFR Parts 60 and 75, the MFS can determine Hg°, Hg0x, and 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 amalgamation. The system extracts a small sample flow from the flue
gas stream and immediately dilutes it inside the probe. Any Hg0x 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 fluorescence 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, a heated umbilical line, a probe controller,
a 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 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).
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VERIFICATION RESULTS
The RA of the Thermo Electron MFS was 16.4% for HgT, based on comparison to 11 OH reference results. The
overall average value from that set of OH data was 1.008 micrograms per dry standard cubic meter (ug/dscm),
respectively, whereas that from the MFS was 1.090 ug/dscm, a difference of 0.082 ug/dscm.
The linearity error 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.
_Original signed by Gregory A. Mack 2/16/07 _Original signed by Sally Gutierrez 4/4/07
Gregory A. Mack Date Sally Gutierrez Date
Vice President Director
Energy, Transportation, and Environment Division National Risk Management Research Laboratory
Battelle Office of Research and Development
U.S. Environmental Protection Agency
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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