xvEPA
United States
Environmental Protection
Agency
Office of Air Quality
Planning and Standards
Research Triangle Park NC 27711
EPA-340/1-83-016
January 1983
Stationary Source Compliance Series
Transportable
Continuous
Emission
Monitoring
System
Operational
Protocol:
Instrumental
Monitoring of SO2,
IMOx,CO2, and
O2 Effluent
Concentrations
-------
EPA-340/1-83-016
Transportable Continuous Emission
Monitoring System
Operational Protocol:
Instrumental Monitoring of SO2, NOx, CO2,
and O2 Effluent Concentrations
Prepared by:
James W. Peeler
Entropy Environmentalists, Inc.
Research Triangle Park
North Carolina
Prepared for:
Louis R. Paley
Stationary Source Compliance Division
United States Environmental Protection Agency
SSCD Contract No. 68-01-6317
U.S. Environmental Protection Agency
Region V, Library
230 South Dearborn Street
Chicago, Illinois 606Q4J
U.S. ENVIRONMENTAL PROTECTION AGENCY
Office of Air Quality Planning and Standards
Stationary Source Compliance Division
Washington, D.C. 20460
January 1983
-------
The Stationary Source Compliance series of reports is issued by the
Office of Air Quality Planning and Standards, U. S Environmental
Protection Agency, to assist Regional Offices in activities related to
compliance with implementation plans, new source emission standards,
and hazardous emission standards to be developed under the Clean Air
Act. Copies of Stationary Source Compliance Reports are available -
as supplies permit - from Library Services, U.S. Environmental
Protection Agency, MD-35, Research Triangle Park, North Carolina
27711, or may be obtained, for a nominal cost, from the National
Technical Information Service, 5285 Port Royal Road, Springfield,
Virginia 22151.
This report has been reviewed by the Office of Air Quality Planning
and Standards, U.S. Environmental Protection Agency, and approved for
publication as received from Entropy Environmentalists, Inc. Approval
does not signify that the contents necessarily reflect the views and
policies of the U.S. Environmental Protection Agency, nor does mention
of trade names or commercial products constitute endorsement or
recommendation for use.
ii
-------
ABSTRACT
A transportable continuous emission monitoring system (TCEMS) capable of
providing reliable and accurate effluent measurements of SO , NO/NO uO ,
2 x 2
and/or CL has been developed and field tested at numerous industrial and
utility boilers. This report presents the operational protocol for the TCEMS,
including set-up, operation, calibration, quality assurance, and data
reduction procedures. The TCEMS and the operational protocol are designed for
use in conducting source emission tests, continuous emission monitor (CEM)
relative accuracy tests, and stratification tests. Extensive field testing
has shown that the TCEMS can be set up, calibrated, and recording accurate and
precise data within two to four hours after arrival at the site.
iii
-------
TABLE OF CONTENTS
Execut ive Summary» i
Introduction 1
Section I. Transportable Monitoring System: Principle and Applicability.. 3
A. Principle - , 3
B. Applicability 3
Section II. Apparatus 5
A. Pollutant/Diluent Analyzer 5
B. Sample Handling System 5
C. Data Handling System - Recorders 11
Section III. Installation 13
A. Utility Requirements 14
B. Sample Handling System Installation 14
C. Analyzer Installation 19
D. Data Recorder Installation 19
Section IV. Start-Up Procedures , 21
A. Leak Check Procedures 21
B. Analyzer/Recorder Start-Up 21
C. Sample Handling System Start-Up 22
Section V. Calibration 25
A. Analyzer Calibrations 25
B. Data Recorder Calibrations 28
C. Total System Calibrations 30
Section 6. Sampling Procedures 33
A. Final TCEMS Adjustments 33
B. Sampling Probes 33
C. Sampling Duration/Calibration Frequency 36
Section 7. Quality Assurance Procedures 39
A. Analyzers 39
B. Sample Handling System 41
C. Data Handling System - Recorders 43
D. Calibration Gases 43
Section 8. Data Interpretation 45
A. General Data Interpretation Procedures 45
B. S02 and NO Source Performance Test Results. 47
C. SO and NO GEM Relative Accuracy Tests 48
2 x
Appendix I.
Appendix II.
Principles of Operation:
SO , NO/NO , CO.,, and 0
Z. X
Analyzers
,-i 9 duvji O
Stratification Testing Methodology for
Gaseous Effluent Constituents
-------
INTRODUCTION
The use of portable and transportable continuous emission monitoring sys-
tems (TCEMSs) by industry, consultants, and control agencies for the measure-
ment of gaseous effluent constituents at stationary sources has increased £_g-
nificantly in recent years. Control agencies can use TCEMSs cost effectively
to conduct a variety of inspection/audit activities, such as: (1) measurement
of S02 and/or NOX emissions, (2) determination of the accuracy of installed
continuous emission monitor (CEM) data, and (3) evaluation of the
representativeness of proposed or existing CEM sampling locations. Source
owners and operators can use TCEMSs to ensure compliance with applicable regu-
lations and to ensure maximum process and control system performance.
The TCEMS offers several advantages over conventional Reference Method
methodology for S09 and NO measurements. Both field set-up time and manpower
^. X
requirements are significantly reduced when a TCEMS is employed. In addition,
all or any combination of effluent constituents (S02, NO/NC^, C02, and 02) can
be measured concurrently and with no increase in manpower requirements. TCEMs
provide "real time" data, which allows corrective actions or additional tests
to be initiated immediately, avoiding the usual delays caused by the
time-consuming laboratory analyses and calculations required by the Reference
Methods. The immediate availability of the data can also shorten the time re-
quired for relative accuracy tests. Finally, the TCEMS offers great
versatility, allowing auxiliary tests (such as checks of monitor installation
locations for stratification or checks of a source's calibration gas
standards) to be conducted easily.
This report presents a TCEMS operational protocol that has been success-
fully field tested. The protocol specifies explicit, detailed procedures for
operating the TCEMS during field tests to ensure consistent and valid results
and to minimize the influence of operator expertise on the test results.
1
-------
SECTION I.
TRANSPORTABLE CONTINUOUS EMISSION MONITORING SYSTEM:
PRINCIPLE AND APPLICABILITY
A. Principle
An effluent gas sample is continuously extracted from a stack or duct
through one or more single-point sampling probes. The sample is conditioned
(i.e., water vapor and particulate matter are removed), and the sample is then
transported to a series of gas analyzers for the determination of SO., NO ,
C02, and 02>
B. Applicability
The transportable continuous emission monitoring system (TCEMS) is used
for the determination of S02, NO, NO , CO , and 0? concentrations at
fossil-fuel-fired combustion processes. Before this methodology can be applied
to other source categories and source-specific conditions, the validity of the
TCEMS results must be established through sufficient comparative reference
method test results.
-------
SECTION II.
APPARATUS
A. Pollutant/Diluent Analyzer
Table 1 lists the pollutant or diluent component, manufacturer, model
number, and analytical technique for each analyzer in the prototype TCEMS.
(The principles of operation for each analyzer are discussed in Appendix I of
this report.)
Table 1.
Pollutant/ Manufacturer Model No. Analytical Technique
Diluent
so2
NO, NO
C00
Bee km an
Beckman
Beckman
865
951
864
IR Differential Absorption
Spectrometer
Chemiluminescence
IR Differential Absorption
Teledyne
Spectrometer
320P-4 Electrocatalytic Fuel Cell
The S0p, C0?, and NO/NO analyzers are mounted in environmental isolated
instrument cabinets for protection from adverse weather, temperature
variations, and mechanical vibrations. Each analyzer is wrapped in two inches
of polyurethane foam within the instrument cabinet. The instrument cabinet is
also equipped with receptacles for electrical power, recorder wiring, and
connectors for sample lines. (See Figures 1 and 2.)
B. Sample Handling System
The sample handling system provides a continuously conditioned (water
vapor and particulate removed) sample gas flow for each of the gas analyzers.
-------
Figure 1.
NOX Cabinet Plumbing Diagram
Sample
Exhaust
Air/O2
Inlet
Sample
Inlet
-©•
*2.
*3.
*4.
*5.
Sample pressure regulator
Sample rotameter
Sample flow control valve
Reaction chamber
Ozone generator
*Built into the monitor
-------
Figure 2.
Cabinet Plumbing Diagram
Sample
Tnl^h to, H
^ L
. ^'4
7
1 — l
J~T~I «tf
I. SO.., or CO- gas monitor
2. Pressure gauge (in. of 1^0)
3. Sample rotameter with flow control valve
4. Bypass pressure regulator
5. Three-way calibration valve
6. Desiccant
7. Perma Pure dryer
8. Purge rotameter
9. Flow control valve
10. Purge pump
-------
Table 2 lists the major components.
Table 2.
1. In-stack probe
2. In-stack coarse filter
3. Heated sample line
4. Primary moisture removal system
5. Gas transport tubing
6. Secondary moisture removal system
7. Fine filter
8. Pump
9. Calibration systems
1. Sampling Probe
Single-point sampling probes constructed of 316 stainless steel are used
in the TCEMS. The sample probes are wrapped with Nichrome wire; a variable
transformer is used to control the electrical power supplied to heat the probe.
For stratification tests, two single-point probes are used in a
functionally parallel, time sharing fashion; one probe serves as the reference
measurement, and the other serves as a traverse measurement. Each probe is
equipped with a shut-off valve to facilitate switching from one to the other.
2. Coarse In-Stack Filter
A glass wool plug is inserted into the enlarged tip of the sampling probe
to serve as a coarse in-stack filter. Quartz or borosilicate glass wool must
be used.
-------
3. Sampling Lines
The outlet of the sampling probe(s) is connected to the primary moisture
removal system by 25 feet of 3/8-inch O.D. Teflon tubing wrapped with heating
wire and insulation. Power to the sample line heaters is controlled with a
variable transformer.
4. Primary Moisture Removal System
Combustion effluent streams contain significant amounts of water vapor.
Therefore, an ice bath condenser is used as the primary moisture removal system
to allow a relatively dry sample stream to be transported through unheated gas
lines to the analyzer location. The ice bath condenser is constructed from a
20-foot section of 3/8-inch Teflon tubing wrapped in a 6-inch diameter coil.
The gas passes through this coil to a condensate trap and then exits through a
second port. A third and fourth port are incorporated in the condensate trap
to facilitate both the injection of calibration gases and the draining of
accumulated condensate. This entire system is contained in an insulated ice
bath.
5. Gas Transport Tubing
3/8-inch O.D. Teflon tubing is used to transport the sample from the
primary moisture removal system to the analyzer location. The length of the
gas transport line should be kept as short as practical, but may be as long as
300 feet.
-------
6. Secondary Moisture Removal System
A 12-inch Perma Pure dryer is used as a secondary moisture removal system
to ensure that the sample stream is completely dry. A Thomas diaphragm pump
pulls ambient air through a cartridge containing approximately 350 grams of
8-mesh Drierite and then through the outer shell of the dryer. Purge air flow
rate is controlled by a rotameter and an in-line needle valve.
7. Fine Particulate Filters
A stainless steel, in-line, *)0-mm filter holder, and 8-micron glass
filters are used before the permeation dryer to prevent plugging with
particulate matter.
The N0-N0x analyzer requires a fine filter of less than 2 microns. A
40-mm Teflon filter holder and 2-micron glass filter paper are installed on the
analyzer inlet port.
8. Pump
The TCEMS may be operated using either a Metal Bellows (MB) Model 158 or
Thomas Model 2107CA18 pump. All internal parts of the pump that contact the
gas sample are constructed of 316 stainless steel or Teflon.
9. Calibration Gas Systems
The sample handling system is equipped with two calibration systems to
facilitate calibration of the total system: one local system to inject gases
directly into the analyzers and a second system to inject calibration gases
10
-------
directly after the in-stack probe. Both calibration systems are constructed of
stainless steel or Teflon components.
All regulators used to control delivery pressures of pollutant gas
calibration mixtures are constructed of 316 stainless steel; regulators
constructed of other materials may be used for 0^ and C0_ mixtures and zero air
or nitrogen.
C. Data Handling System - Recorders
Two dual pen Soltec Model S4202 recorders are used to document permanently
the outputs of the four analyzers.
11
-------
SECTION III.
INSTALLATION
The sampling and analysis sites may be separated by as much as 300 <>e?
The sampling site is dictated by: (1) the applicable source performance test
and/or monitor performance specification test regulatory provisions, (2) the
purpose of the test being conducted, and (3) the availability of accessible
sampling ports (See Section VI, Sampling Procedures). The sampling probe,
sampling line, primary moisture removal system, and stack calibration system
must be installed at the sampling site. All other components of the sample
handling system may be installed with the analyzers and data recorders at the
analysis site.
The analysis site should be as close as is practical to the sampling site
to minimize the response time of the system. Also, because the instruments are
sensitive, the analysis location should be free from vibration. In selecting
the analysis site, the following should also be considered: (1) operator
convenience, (2) communication needs, (3) protection from severe environmental
conditions (weather, noise, dust, temperature, noxious gases, etc.), and
(4) available utilities.
13
-------
A. Utility Requirements
The analysis site power requirements are: 115 +_ 15 VAC rms at 60 -f 0.5 Hz.
Sufficient power must be available to operate the sample and purge pumps,
analyzers, and data recorders. The supply voltage should be constant, without
sharp fluctuations. After initial start-up, the power should be rechecked with
all of the equipment operating to assure that proper voltage requirements are
met.
The sampling site power requirements are nominal 115 VAC to provide power
for operation of probe and sampling line heaters.
B. Sample Handling System Installation
The sample handling system is constructed of the sub-assemblies described
in Table 3.
Table 3.
Assembly
Probe
Primary Moisture
Removal System
Stack Calibration System
Gas Transport Tubing
Pump
Secondary Moisture
Removal System
Components
Probe; heat traced line.
Ice bath condenser,
probe shut-off valve, cali-
bration shut-off valve,
condenser drain valve.
Toggle shut-off valves and
inlet fittings for cali-
bration gases.
50 to 300 ft of 3/8-inch tubing,
MB 158 pump, or equivalent,
and fittings.
Two Perma Pure dryers, fine
filter, purge pump, purge
desiccant.
14
-------
Flow Control System Stack gas shut-off toggle
valve, flow meter, ground
level calibration system.
Analyzer Flow Control Analyzer flow meters, flow
System control valves, and bypass
flow control valve.
Figure 3 illustrates the interconnection of these sub-assemblies. Figure 4
shows the complete assembly of the sample handling system on a
component-by-component basis.
1. Sampling Site
The probe is connected to the primary moisture removal system inlet by
3/8-inch heat-traced sample line. The calibration gases are connected to the
calibration system by 1/4-inch Teflon lines; each gas is connected to its
respective inlet. The output line of this system is connected to the
calibration input fitting on the moisture removal system. A 50- to 300-foot,
3/8-inch Teflon gas transport line is connected to the outlet of the moisture
removal system and run to ground level.
2. Ground Level
The 50- to 300-foot gas transport line is connected to the gas inlet port
of the pump. Ground level calibration gases are connected to their respective
ports by 1/4-inch Teflon tubing. The outlet of the pump attaches to the inlet
of the secondary moisture removal system. The outlets of the Perma Pure dryers
are connected to the inlets of the individual analyzer flow systems. In
addition, the purge pump and purge desiccant are attached to the inlet and
outlets, respectively, of the Perma Pure dryer shell.
15
-------
Stack
Calibration
System
Monitor
Calibration
System
(Ground Level)
f
Moisture
Removal
System
Sample
Flow
System
so2
Monitor
NOX
Monitor
co2
Monitor
Probe
4=3
Stack
°2
Monitor
Bypass
or
Additional
Monitor
Rec
Rec
Rec
Rec
Figure 3. Continuous Gas Emission Monitor Block Diagram
16
-------
10
Figure 4.
Sample handling systei
(legend follows)
17
-------
Figure 4.
Sample Handling System
Legend
1. Coarse filter
2. Heated probe
3. Heat trace sample line
4. Shut-off valve
5. Fine filter
6. Flow control valve
7. Ice bath condenser
8. Condensate drain
9. 3/8-inch gas transport tubing
10. Sample Pump
11. Stack calibration system
12. Ground level calibration system
13. Moisture removal system
14. Sample rotameter
15. Monitor flow control system
18
-------
C. Analyzer Installation
All analyzer sample inlets should be connected to the appropriate lines
from the analyzer flow manifold included within the sample handling system.
All analyzer outlets and the sample by-pass flow should be properly vented to
prevent a buildup of noxious gases at the analysis site. The vent lines shou. ,<.1
be large enough so that they do not cause a back pressure on any of the
instruments.
The NO/NO analyzer requires compressed dry air for the operation of its
A
ozone generator. The output of the zero air cylinder regulator is attached to
the air inlet on the back of the monitor.
D. Data Recorder Installation
The strip chart recorders should be mounted adjacent to the analyzers in
order to facilitate comparisons of meter readings and strip chart recorder
values.
The SO and CO- analyzers have three output wires: one red, one black, and
one white. The white wire is not used. The red wire should be connected to
the positive terminal, and the black wire to the negative terminal. No ground
wire is necessary.
/
The NO/NO and 0~ analyzers have a two-wire output, with the positive
going to the red terminal of the recorder and the negative to the black
terminal.
Those monitors with environmental cabinets are equipped with red and black
terminals with color-coded banana plugs, which simply plug into the recorders.
19
-------
SECTION IV.
START-UP PROCEDURES
A. Leak Check Procedures
After the entire system has been assembled, a preliminary leak check is
conducted. To perform a leak check, first shut off the toggle valve
immediately after the probe. Next, shut off the monitor flow control valves.
Cap the purge fittings of the Perma Pure dryer. Open the calibration system
toggle valve at stack or ground level. Open the nitrogen cylinder valve., and
adjust the regulator for approximately 20 psig. Wait momentarily for the whole
system to be pressurized. Shut off the cylinder valve, and watch for any
decrease in pressure on the cylinder pressure gauge for at least one minute.
If a decrease in pressure is observed, the leak must be located and repaired.
If no decrease in pressure occurs, the system is leak-free and the probe toggle
valve can be opened to release the pressure.
B. Analyzer/Recorder Start-Up
1- S02 Analyzer
Turn the analyzer on, and allow a minimum of one hour for warm-up time.
2. N0/N0x Analyzer
Turn on the dry air cylinder, and adjust the pressure regulator output to
*»0 psig. Open the front of the analyzer, and adjust the ozone pressure
regulator to 20 psig. Turn on the power to the analyzer, and allow one hour
for the instrument to warm up.
21
-------
3- C02 Analyzer
Apply power to the analyzer, and allow a minimum of one hour warm-up time.
**• ®2 Analyzer
No start-up procedures are required for the 0^ analyzer, since it is
battery powered and completely self-contained.
5. Data Recorders
Two power switches are located on the front of the recorders, one for
recorder power and one for chart drive. Turn on the main power, and allow the
amplifier to warm up.
C. Sample Handling System Start-Up
1. Sampling Probe
Plug the probe heaters into the appropriate variable transformers, and
adjust to the proper voltages (80 to 90J).
2. Sampling Line
Plug in the sample line heaters to the appropriate variable transformers.
Adjust the voltages to approximately 80 to 90$ of scale.
3. Ice Bath Condenser
Fill the condenser insulated container with ice.
22
-------
M. Perma Pure Eryer
The Perma Pure dryer requires a dry air purge for the removal of water.
The pump draws ambient air through a desiccant and through the dryer. Turn on
the pump, adjust the flow rate to 8 L/min., and allow 30 minutes for
equilibrium to be established.
5. Pump
After the rest of the system has come to equilibrium, open the probe valve
and the sample by-pass valve. Turn on the pump, and stack gas will begin to
flow through the system. After the system has been purged with effluent, adjust
all of the monitor flow control valves to the proper flow rates for each of the
instruments: SO- = 1 L/min, CO- = 1 L/min, N0x = 4 L/min, and 02 = 0.5 L/min.
23
-------
SECTION V.
CALIBRATION
Proper calibration of the TCEMS requires sequential calibration procedures
be conducted for : (1) all pollutant and diluent analyzers in use, (2) data
recorders for each analyzer in use, and (3) total system calibration for each
monitoring channel in use. To ensure the validity of all measurements
obtained, the operator must follow all prescribed calibration procedures, and
the TCEMS must demonstrate conformance with all prescribed acceptable
calibration criteria.
A. Analyzer Calibrations
1. SO- Analyzer
Shut off the pump, and close the probe valve. Shut off the flow system
toggle valve. Open the ground level calibration toggle valve. Open the
cylinder cut-off valves, and adjust the regulators to provide delivery pressure
of 5 psig. Open the N2 toggle valve and adjust the S02 flow meter to 1 L/min.
Check the built-in pressure gauge to make sure the cell pressure is below 4-in.
H^O. If it is not, adjust the sample bypass regulator to obtain 4-in. H?0.
Turn the range switch to "Tune" and look for a reading of 30 to 40 percent. If
this reading is not obtained, refer to Section 7.3 of the Beckman 865 NDIR S0p
Analyzer manual. Turn on the recorder for the instrument. Switch from "Tune"
to Range 1. The reading should be zero; if not, adjust the zero control to
zero. Switch between Ranges 1 and 3, to see if both read zero. If zero is not
obtained on both ranges, refer to Section 7.5 of the instrument manual for bias
adjustment procedures. If zero is the same for both Range 1 and Range 3,
return to Range 1 and turn off N?.
25
-------
Inject a high range span gas, and set the gain control for the appropriate
reading. If the reading cannot be obtained, or if a negative deflection is
observed, refer to Section 7.6 of the instrument manual. Once the proper
deflection is obtained, shut off the high range gas, and inject a second gas in
the mid-range. If the proper reading is not obtained, the linearizer circuit
is out of calibration. The linearizer circuit calibration procedure is
contained in the appendix of the instrument manual. Once the proper output has
been obtained, the instrument is ready for use. Shut off the span gases and
the flow control valve, and proceed to the next analyzer.
2. N0/N0x Analyzer
Set the monitor to the NO mode, and select the range to be used (e.g.,
1000 ppm range). Inject the N2 gas. Open the flow control valve so that a
reading of 5 cfh is obtained. Open the front cover and adjust the sample
pressure regulator for 4 psi. Also adjust the sample bypass flow meter to 20
(i.e., 2000 cc/min). If zero is not obtained, adjust the zero control for zero
meter output. If zero cannot be obtained, refer to Section 6 of the Beckman
951 Chemiluminescence Analyzer instrument manual.
Once zero has b*"m obtained, inject a high concentration span gas by
opening the appropriate toggle valve. Open the front of the instrument and
check the sample pressure (4 psi) and the sample byass flow (20). Close the
front, and watch for the proper deflection of the meter or recorder. If
necessary, adjust the span control for the proper reading. If the proper
reading cannot be obtained, refer to Section 6 of the instrument manual. Once
the proper reading is shown, shut off the high span gas, and inject an
intermediate gas to check for linearity. Make sure that the sample pressure and
the sample bypass flow are set correctly. If the reading is incorrect, refer
26
-------
to Section 6 of the instrument manual. If the correct readings are obtained,
shut off the span gases, and proceed to the next analyzer.
3. COp Analyzer
Shut off the pump, and close off the probe valve. Shut off the flow
system toggle valve. Open the ground level calibration toggle valve. Open the
cylinder cut-off valves so that N,, and C02 gases may be injected. Adjust the
regulators for 5 psig. Open the N? toggle valve, and adjust the C0? flow meter
to 1 L/min. Check the built-in cell pressure gauge. If the reading is not
below 4-in. H^O, adjust the bypass regulator for minimum cell pressure while
maintaining a 1 L/min sample flow.
While continuing to inject Np, turn the range switch to "Tune" and check
for a reading of 30 to 40 percent. If this reading is not obtained, refer to
Section 7.3 of the Beckman 864 C0? Analyzer instrument manual. Turn on the
recorder for the instrument. Switch from "Tune" to Range 1. The reading
should be zero; if not, adjust the zero control to zero. Switch between Range
1 and Range 3 to see if both read zero. If zero is not obtained on both
ranges, refer to section 7.5 for bias adjustment. If zero is the same for both
Range 1 and Range 3, return to Range 1 and turn off the N~ toggle valve.
Inject a high range span gas and set the gain control for the appropriate
reading. If the reading cannot be obtained, or if a negative deflection is
observed, refer to Section 7.6 of the instrument manual. Once the proper
deflection has been obtained, shut off the high range gas, and inject a second
gas in the mid range. If the proper reading is not obtained, the linearizer
circuit is out of calibration. The linearizer circuit calibration procedure is
contained in the appendix to the instrument manual.
27
-------
Once the proper output }
-------
this iterative procedure until the zero and span values are balanced.
2. NO/NO Channel
JL
The output of the NO/NO analyzer is 0 to 1 volt DC. Zero the monitor and
adjust the recorder zero for 10 percent of the scale. Inject a high range gas,
and check that the recorder reads the same as the meter. If the readings are
not the same, refer to the Soltec recorder manual for the span adjustment
procedures, Section ^. Check the zero and upscale readings until the zero and
span settings are balanced.
3. C0_ Channel
The C0_ analyzer is equipped with a 4- to 20-ma output. The recorders
will accept a voltage input only. The recorders have been supplied with a
50-ohm resistor to convert the current output to a voltage. Since 4 ma is
equivalent to zero concentrations, and since a finite voltage is developed, a
variable span recorder must be used. The correct zero and span settings may be
achieved by pulling the recorder zero control to its "out" position. Select
the 1 volt range. With the instrument meter on zero, adjust the recorder zero
control for 10 percent of the recorder scale. Inject a gas into the instrument
for an upscale deflection, and adjust the variable span potentiometer to obtain
the same value as the meter reading. Return to zero, and adjust if necessary.
Inject the gas again, and adjust the span variable again. Continue this
iterative procedure until the zero and span values are balanced.
29
-------
4. 02 Channel
The output of the analyzer is 0 to 100 mv DC. Inject a low concentration
of Op into the monitor, and adjust the recorder for 10 percent of scale above
the low concentration value. Inject a high range gas, and check that the
recorder reads the same as the meter. If the readings are not the same, refer
to the Soltec recorder manual for the span adjustment procedures, Section 3-
Check the low and upscale readings until the low and span settings for the
recorder are balanced.
C. Total System Calibration
After the individual analyzer and data recorder calibrations are
completed, a total system calibration must be performed. All span gases used
in this check should represent values close to those of the stack effluent.
Shut off the probe valve and the pump. Open the stack calibration system toggle
valve. Open the N~ and the span gas cylinder valves, and adjust the output of
the regulators to 10 psig. Open the N? toggle valve. Turn on the pump and
adjust the instrument flow meters for the proper flows (SOp = 1 L/min; NO-NO
= 4 L/min; C0? » 1 L/min; and 0_ = 0.5 L/min). All instrument outputs should
equal zero. Open the system to ambient air to check whether air and N? give the
same reading. If not, the Perma Pure dryer has not yet come to equilibrium,
and a longer period of time is necessary for the dryer to purge.
[Note: Since the S0_ analyzer is subject to H?0
interference, a zero offset may be detected on the SO^ analyzer
when the total system calibration is attempted. The zero offset
will occur because of a reverse action in the Perma Pure drying
process during calibration. When the purge gas is not completely
dry, the water vapor permeates from the outer shell of the dryer
to the inner shell. This permeation occurs because the
calibration gases are dryer than the purge gases, and the
diffusion potential is temporarily reversed.]
30
-------
Inject SOp and record the responses of the SOp analyzer and data recorder.
Shut off the SOp, and inject NO , COp, and Op consecutively. Record the
response of the analyzer and the recorder for each measurement. During these
calibration gas injections, only the analyzer corresponding to the particular
span gas injected should provide a non-zero output.
The response of each analyzer and each data recorder must be converted to
units of concentration and compared to the assigned value of the calibration
gas mixture used in the system calibration. The response must be within _+_ 3
percent of the calibration gas value for the performance of each monitoring
channel to be considered acceptable. If such results cannot be obtained,
necessary adjustments and/or repairs must be made, and the entire calibration
procedure repeated.
31
-------
SECTION VI.
SAMPLING PROCEDURES
Sampling can commence only after all calibration procedures have been
successfully completed.
A. Final TCEMS Adjustments
To sample stack gases, close all calibration system toggle valves, and
open the probe toggle valve. Open the bypass valve on the analyzer flow
system, and turn on the pump. Adjust the S0? and C0? flow meters to 1 L/min.
Adjust the NO-NO flow meter to 4 L/min. Open the front panel of the NO-NO
analyzer, and adjust the sample pressure to 4 psi, and the bypass flow to 20
(i.e., 2000 cc). Adjust the Op flow meter to 0.5 L/min. If these flows
cannot be established, close the bypass valve until all flows are balanced.
All instruments should now correctly read the effluent concentration values.
B. Sampling Points
Selection of sampling points for the TCEMS depends upon the type of test
being conducted (source performance test or monitor performance test), and upon
the constraints imposed by applicable regulations and available sampling ports.
1. Emission Tests
All relevant regulatory provisions regarding the location of Reference
Method sampling points during source performance tests apply to the TCEMS
during tests to determine S02 and/or NO emission levels. Whereever such
33
-------
provisions do not specifically prescribe sampling points and where the sampling
location may not provide representative results, a stratification test must be
performed using the procedures detailed in Appendix II of this report.
2. GEM Performance Tests
All relevant regulatory provisions regarding the location of Reference
Method sampling points during relative accuracy tests apply to the TCEMS during
GEM performance tests.
If relative accuracy testing is conducted at a location other than the
installed GEM location where the TCEMS location may not give representative
results, a stratification test must be performed at the TCEMS location
according to the procedures specified in Appendix II of this report. The
relative accuracy test results that are obtained where the TCEMS location is
separated from the installed CEMS location cannot distinguish between factors
impacting the actual performance of the installed GEM and the potential effects
of stratification at the installed GEM location.
If relative accuracy testing is conducted at the same location as the
installed GEM location where the location may not provide representative
results, a stratification test must be performed according to the procedures
specified in Appendix II of this report. When relative accuracy testing is
conducted at the same location as the installed GEM, the following sampling
points must be used:
34
-------
a. Single Point GEMS
For single point GEMS, the TCEMS sampling probe should be located no
further than 30 cm (or 5 percent of the equivalent diameter of the cross
section, whichever is less) from the pollutant GEM sampling probe.
b. Multipoint GEMS
For multipoint GEMS, each TCEMS sampling probe traverse point should be
located no further than 30 cm (or 5 percent of the equivalent diameter of the
cross section, whichever is less) from each corresponding pollutant OEM
sampling point.
c. Path GEMS
For limited path and path GEMS, three TCEMS sampling points should be
located on a line parallel to the CEM path and no further than 30 cm (or 5
percent of the equivalent diameter of the cross section, whichever is less)
from the centerline of the CEM path. The three points for the TCEMS sampling
probe should correspond to points in the CEM path at 16.7, 50.0, and 83.3
percent of the effective length of the CEM path.
d. Alternative Locations
Other locations may be used if a stratification check is conducted and the
pollutant and diluent constituents of the gas stream are found to be of uniform
concentration throughout the measurement area of interest within the stack.
(See Appendix II.)
35
-------
C. Sampling Duration/Calibration Frequency
Sampling durations for the TCEMS must be consistent with the applicable
regulatory provisions for source performance tests and monitor relative
accuracy tests.
1• S02 and N0x Emission Tests at NSPS Subpart D Sources
After all calibration procedures have been successfully completed, the
TCEMS must be operated for three one-hour sampling runs. A system calibration
of the TCEMS (See Section V, C) must be successfully completed before and after
each sampling run. If the system calibration is not successfully completed,
adjustments and/or repairs to the TCEMS must be made and a complete
recalibration of the TCEMS must be performed.
Data obtained during a sampling run followed by an unsuccessful system
calibration may not be included in the calculation of emission levels.
2. Relative Accuracy Tests of Installed SO- and NO GEMS
After all calibration procedures have been successfully completed, the
TCEMS must be operated for 9 sampling runs to provide results comparable to the
relative accuracy test of Appendix B, Performance Specifications 2 and 3,
40 CFR 60. The TCEMS must be operated for 6 sampling runs to provide results
comparable to the relative accuracy audit of proposed Appendix F. The duration
of each sampling run shall be 20 minutes. A system calibration of the TCEMS
must be successfully completed before and after each sampling run. If a system
calibration is not successfully completed, adjustments and/or repairs to the
TCEMS must be made and a complete calibration of the TCEMS must be performed.
Data obtained during a sampling run that is followed by an unsuccessful system
36
-------
calibration may not be included in the determination of the installed CEM
relative accuracy.
In those cases when either gross disparities or excellent agreement
between the installed CEMS and the TCEMS are observed during the initial
sampling runs, it is usually possible to predict accurately the outcome of the
relative accuracy determination before all the required sampling runs are
completed. Table U lists the criteria for termination of relative accuracy
sampling where conformance with the promulgated Performance Specifications is
not required. Procedures for calculation of the mean difference are specified
in Section VIII.
Table 4.
Sample Runs , Results
Completed Percent Difference Installed CEM Performance
3
3
6
6
PD
PD > 20%
PD < 10%
PD > 20%
PD < 14%
= Percent Difference =
unacceptable
acceptable
unacceptable
acceptable
N
z (CEMS. -
i 1
N
E TCEMS.
TCEMS . )
N = Number of sample runs
These criteria are based on limited available data at the time of
preparation of this report; more restrictive criteria will be developed as
additional data become available.
37
-------
SECTION VII.
QUALITY ASSURANCE PROCEDURES
The most important quality assurance procedures for the TCEMS are those
specified for the analyzer, data recorder, and system calibration in Section V.
The calibration results provide the primary basis for assessing the quality of
the measurement results obtained. Additional quality assessment and quality
control procedures are specified below.
A. Analyzers
1 . S02 Analyzer
The SOp analyzer is sensitive to flow rate and sample pressure variations.
Therefore, the bypass valve should be open as far as possible, and the supply
flow rate should be kept at 1 L/min.
[Note: The monitor is equipped with a pressure gauge
calibrated in inches H_0. The pressure of the cell is pe-set by a
bypass regulator. This sample pressure should be maintained at 4
_+_ 0.5 in. HpO.] The operator should check the sample flow rate and
sample pressure during each sampling run.
The S0_ analyzer is equipped with an internal reflector to provide an
upscale calibration check of the analyzer response. The set point of this
refector should be noted during the analyzer calibration procedure. The
internal reflector should be activated periodically during sampling to check
for analyzer drift. Any discrepancy greater than 2 percent between the
analyzer's response to the internal reflector and the results of system
calibrations should be resolved, and the analyzer should be recalibrated.
39
-------
2. NO-NO Analyzer
x
The N0-N0x analyzer is sensitive to sample pressure and sample flow rate
fluctuations. A check of sample pressure (4 psig) and sample bypass flow (20,
indicating a flow of 2000 cc/min.) should be conducted during each sampling
run. A pressure of 20 psi on the ozone pressure gauge will assure that the
ozone generator is receiving enough air flow. The inlet gas sample is passed
through a glass fiber filter to remove particles larger than 2 microns. Before
each field use, the glass filters should be visually checked and replaced if
any discoloration is observed.
3. C0_ Analyzer
The C02 analyzer is sensitive to sample flow rate and sample pressure
fluctuations. Therefore, the bypass valve should be open as far as possible,
and the flow should be kept at 1 L/min.
[Note: The monitor is equipped with a pressure gauge in inches
JUO. The cell pressure is pre-set, but should be checked. The
pressure must be maintained within 4 _^_ 0.5 in. H?0.]
The CO- analyzer is equipped with an internal reflector to provide an
upscale calibration check of the analyzed response. The set point of this
reflector should be noted during the analyzer calibration. The internal
reflector should be periodically activated during sampling to check for
analyzer drift. Any discrepancy greater than 2 percent between the analyzer's
response to the internal reflector and the results of a system calibration
should be resolved, and the analyzer should be recalibrated.
40
-------
4. 0- Analyzer
The Op analyzer has a self-contained battery pack, which should be charged
after every field use. When the analyzer is not in use, the cell cap should be
replaced to prolong the life of the cell. After use, the sample cell should be
purged with air. Sampling time should be as short as possible (approximately 1
minute), in order to extend the life of the cell.
B. Sample Handling System
1. Probe
The probe should be cleaned before and after use. The glass wool plug
must be replaced after each field test. Heater wires should be inspected to
reduce the chance of heater outages during use.
2. Primary Moisture Removal System
The ice bath condenser should be drained and cleaned before and after use.
3. Fine Particulate Filter
This filter should be changed after each use.
4. Secondary Moisture Removal System
The purge air desiccant for the Perma Pure dryer should be replaced after
each use and checked periodically during use. When the desiccant is close to
being spent, it should be replaced immediately. If the desiccant is not
replaced, the moisture in the ambient air will allow a portion of the sample
41
-------
stream moisture to pass through the Perma Pure dryer. This small amount of
moisture represents a negligible volume fraction of the sample, but can cause a
zero offset on the S02 and C02 monitors.
The Perma Pure dryer used in the moisture removal system removes the
effluent moisture in the vapor state. Entrained moisture droplets in the
effluent will cause a saturation of the membranes in the Perma Pure dryer.
This moisture will eventually contaminate the whole monitoring system,
rendering the SO^ and COp monitors incapable of obtaining accurate effluent
measurements. If moisture appears at any point in the system after the dryer,
the total system must be shut down and the problem with moisture carryover
resolved.
5- Gas Transport Tubing
The 50- to 300-foot gas transport lines should be kept as clean as
possible. If necessary, these lines can be cleaned with soapy water and rinsed
thoroughly with distilled water. Afterwards, the lines should be dried with a
continuous flow of ambient air.
6. Pump
No routine maintenance of the sample pump is necessary.
7. Flow System
No maintenance is required.
-------
8. Analyzer Flow System
This system should be maintenance-free. If the rotameters should stick,
wash them with soapy water, and then rinse with distilled water. Do not tighten
the flow valves too tightly; this may cause damage to the valve seats.
C. Data Handling System - Recorders
The recorders should be kept clean in order to reduce friction in the
mechanical moving parts. Calibration should be performed before and after use
to check for amplifier drift.
D. Calibration Gases
Concentration values of calibration gases used with TCEMS may be
determined by either of the following methods:
1. Calibration gas values traceable to NBS standards may be established
according to "Traceability Protocol for Establishing True Concentrations of
Gases Used for Calibration and Audits of Continuous Source Emission Monitors
(Protocol No. 1)." June 15, 1978.
2. Triplicate reference method analyses of each calibration gas may be
performed. Each of the individual analytical results must be within 10 percent
(or 15 ppm, whichever is greater) of the average; otherwise, discard the entire
set, and repeat the triplicate analyses. If the average of the triplicate
reference method test results is within 5 percent of the calibration gas
manufacturer's tag value, use the tag value; otherwise, conduct at least 3
additional reference method test analyses until the results of 6 individual
runs (i.e., the 3 original plus 3 additional) agree within 10 percent or 15
43
-------
ppm, whichever is greater, of the average. Then use this average for the
cylinder value.
44
-------
SECTION VIII.
DATA INTERPRETATION
All data reduction procedures are based upon the fully documented strip
chart records of the TCEMS. All zero, span, and effluent measurements must be
clearly marked for each of the monitoring channels in use.
A. General Data Interpretation Procedures
The zero and span system calibration results for each monitoring channel
are used to evaluate all effluent monitoring results. The following procedure
must be used:
zero level = strip chart reading during zero gas
(air) injection (in chart divisions)
span level = strip chart reading during upscale
system calibration (in chart divisions)
span value = calibration gas concentration
corresponding to upscale system
calibration (in ppm or percent)
effluent level = strip chart reading of effluent
measurement (in chart divisions)
effluent value = effluent concentration (in ppm or percent)
scale factor = span value
span levei - zero level (in pPm Per chart division)
effluent value = [effluent level-zero lev el] x[ scale factor]
The above procedure is illustrated in Figure 5.
45
-------
average effluent
level = 45
zero level =10
I
span level = 52
span concentration
= 452 ppm
scale factor =
452
= 10.752 ppm/chart division
52 - 10
effluent value = [45-10] x 10.762 = 377 ppm
Figure 5. Interpretation of strip chart records
46
-------
B. SO and NO Source Performance Test Results
,1 x
Interpretation of TCEMS data for determining source emission levels should
be as consistent as possible with applicable reference method and regulatory
considerations.
For SO emission level determinations at NSPS Subpart D sources, the
following data reduction procedures are applicable:
(1) Ignore the first 5 minutes of sampling data obtained during each
one-hour sampling run to allow for complete system stabilization
following the system calibration. Divide the remaining sampling
time into two equal duration sampling periods per sampling run
for both the SO and diluent (CO- or Op) monitoring channels.
(2) Determine the average effluent level for both the SO and
diluent monitoring channels for each sampling period. Convert
the effluent levels to equivalent effluent concentrations for
both monitoring channels using the procedure in "A" above.
(3) Using the SO and diluent, concentrations, calculate emission
levels in units of lbs/10 Btu using procedures specified in
Subpart D for each sampling period.
(4) Average the two sampling period results obtained during each
run .
(5) Arrange the three sample run results in units of lbs/10 Btu to
determine the test result.
For NO emission level determinations at NSPS Subpart D sources, the same
procedures apply as for S0_ determinations, except that each sampling run may
be treated as a single value (i.e. the sampling run need not be divided into
two sampling periods) . Note that the results of three sample runs expressed in
units of lbs/10 Btu are averaged to obtain the test result.
47
-------
C. SO., and NO^ GEM Relative Accuracy Tests
(1) Ignore the first 5 minutes of data obtained during each sampling
run to allow for complete system stabilization following the
system calibration.
(2) Determine the integrated average effluent levels for all
monitoring channels in use for each sampling run. Convert the
effluent levels to equivalent effluent concentrations for each
monitoring channel using the procedure in "A" above. Also,
calculate the average pollutant and diluent concentrations using
the results of all sampling runs.
(3) Using the pollutant and diluent measurement results, calculate
the emission levels in units of lbs/10 Btu for each sampling
run. Calculate the average of all TCEMS sampling runs in units
of lbs/10 Btu.
(4) Determine the installed CEMS monitoring results (pollutant
concentration, diluent concentration, and emission levels) for
the periods concurrent with each sampling run of the TCEMS using
the same procedure that is employed by the source operator in
reporting emissions.
(5) The mean difference, 95 percent confidence interval, and
relative accuracy must be computed for each monitoring channel
and for the combined system in units of lbs/10 Btu.
Calculate the algebraic mean difference of the data set as follows
n
MD = 1/n Z V.
where: n = number of data points
D. = sample run ( i) difference
1 (CEMSi - TCEMS^
48
-------
Calculate the 95 percent (two-sided) confidence interval (CI)
as follows :
CI
where:
\/nZD 2 - (ZD V
n
3
4
5
6
7
8
9
fc.975
4.303
3. 182
2.776
2.571
2.447
2.365
2.306
Calculate the relative accuracy (RA) of the data set
as:
iMDl + CI
RA
AVG
where: AVG = average TCEMS value for all
sample runs.
-------
APPENDIX I.
PRINCIPLES OP OPERATION:
S02, NO/NOX, C02, AND 02 ANALYZERS
-------
PRINCIPLES OF OPERATION;
SO,, NO/NO , C00> AND 00 ANALYZERS
—x-
The following discussions briefly outline the operational principles of
each analyzer used in the TCEMS. Additional information may be found in the
instrument manuals provided by the manufacturers.
A. Beckman Model 865 SO,, Analyzer
The Model 865 Infrared SO Analyzer automatically and continuously
determines the concentration of S02 in a flowing gas mixture. The analytical
technique is based on the absorption of infrared energy by S02-
Within the analyzer, two infrared beams of equal energy are directed
through two optical cells: a flow-through sample cell, and a sealed reference
cell. Solid state electronic circuitry continuously measures the difference
between the amounts of infrared energy absorbed in the two cells. The
concentration is read out on a front panel meter which has a range from 0 to
100 percent. A field-selectable current output of either 4 to 20 ma or 10 to
50 ma is provided for strip chart recorder connection.
Since the outputs of these instruments are non-linear, an optional
linearizer circuit board is also included. A solenoid activated reflecting
window is provided for routine upscale calibration. This window reflects a
fixed amount of infrared energy from the sample beam to simulate a specified
concentration of SO^. The instrument is equipped with two ranges: Range 1,
which is adjustable (from 500 to 2500 ppm full scale), and Range 3, which is
equal to 20 percent of Range 1. (Range 2 is omitted from this instrument.)
1-3
-------
B. Beckman Mod^l 931 NO-NO JVnalyzer
JC ' "' T i. i i • iii
The Beckman Model 951, NO-NO Chemiluminescence Analyzer automatically and
X.
continuously monitors a flowing gas mixture. It is capable of performing two
determinations: nitric oxide (NO) and oxides of nitrogen (NO ).
The analyzer employs the Chemiluminescence method of detection. When the
analyzer is adjusted to the NO mode, the sample NO is quantitatively converted
to NO^ by gas phase oxidation with ozone produced within the analyzer. In this
reaction, the N02 molecules are elevated to an electronically excited state and
then immediately revert to a non-excited ground state. The reversion is
accompanied by emission of photons, which impinge on a photomultiplier detector
and generate a low level DC current. The current is then amplified and used to
drive a front panel meter and a recorder.
The NO mode works by the same principles as the NO mode described above,
with the exception that the sample is routed through a converter where NO- is
dissociated to form NO before entering the reaction chamber. The NO reading on
the instrument includes both the NO in the effluent and the NO resulting from
the dissociation of N0_.
The analyzer is equipped with seven ranges: 10, 25, 100, 250, 1000, 2500,
and 10,000 ppm NO or NO .
C. Beckman Model 864 C00 Analyzer
The Beckman Model 864 Infrared C0_ Analyzer automatically and continuously
determines the concentration of CO- in a flowing gas mixture. The analysis is
based on the absorption of infared energy of C0_.
1-4
-------
Within the analyzer, two infrared beams of equal energy are directed
through two optical cells: a flow through sample cell, and a sealed reference
cell. Solid sate electronic circuitry continuously measures the difference
between the amounts of infrared energy absorbed in the two cells. The
concentration is read out on a front panel meter with a scale of 0-100 percent
of set range. A field selectable current output, 4 to 20 ma or 10 to 50 ma, is
provided for a recorder hook-up.
Since the output of the instrument is non-linear, a linearizer circuit
board has been provided. For convenience in a routine upscale calibration, a
solenoid activated reflecting window has been included. This window reflects a
fixed amount of infrared energy from the sample beam to simulate a specific
concentration of C0?. The instrument is equipped with two ranges: Range 1,
equal to 0 to 20% CO , and Range 3, equal to 0 to 5% C02. (Range 2 is omitted
from this instrument.)
D. Teledyne Model 320P-4 Op Analyzer
The Teledyne Model 320P-4 utilizes a patented micro-fuel cell, which
consumes 09 from the atmosphere surrounding the measuring probe. The
consumption of Op generates a proportional electrical current, which is then
amplified and used to drive a built-in front panel meter with a scale of 0 to
25%. Facilities are also provided for a recorder hook-up with a range of 0 to
100 mv DC.
The instrument incorporates its own integral pump and power system. The
power system consists of two permanently mounted rechargeable nickel-cadmium
batteries.
1-5
-------
The 320P-4 monitor has been specifically designed to make spot checks for
Op in flue gas streams.
1-6
-------
APPENDIX II.
STRATIFICATION TESTING METHODOLOGY FOR
GASEOUS EFFLUENT CONSTITUENTS
-------
STRATIFICATION TESTING METHODOLOGY FOR
GASEOUS EFFLUENT CONSTITUENTS
Stratification is the uneven distribution of the effluent component gases
across the cross section of the ductwork or stack which transports the effluent
to the atmosphere. Stratification of gaseous constituents (S0p, NO , 0„, C0_,
etc.) may occur at or downstream of points along the effluent pathway where the
concentration of one of more constituents of the effluent changes. Thus,
points at which air inleakage occurs, points at which control devices affect
pollutant emission levels (such as at the outlet of flue gas desulfurization
systems) , and points at which dissimilar gas streams are combined may result in
stratification of the effluent stream. Samples obtained at locations where
stratification exists may not provide results that are representative of the
entire effluent stream. It is necessary, in some cases, to conduct a test to
detect and/or to quantify the existence of stratification at the existing or
proposed sampling site. The procedures presented in this report are designed
to determine whether effluent stratification is present; this methodology does
not quantify the stratified effluent profile.
Current Performance Specifications for gaseous emission monitors require
that monitors be installed in locations providing measurements that are (or
can be corrected to be) consistently representative of emissions from the
source. These regulations allow the control agency to require stratification
testing at proposed CEM sampling locations where the location cannot be assumed
to be non-stratified.
Proposed revisions to the Performance Specifications (Jan. 26, 19811
Federal Register) allow the monitor to be installed at any location provided
II-3
-------
that the reference method testing to determine the relative accuracy of said
monitors be performed in locations that are representative of the source's
emissions. Stratification testing is an accepted means of demonstrating that
particular sampling locations provide representative emission measurement
results.
Stratification can be measured for either pollutant gases (S0? or NO ) or
diluent gases (0? or C0_) in units of concentration. Alternatively, at steam
generators, stratification may be quantified in units of the applicable
standard (Ibs of pollutant per million Btu of heat input). This second
alternative is useful where both the pollutant and diluent monitors are
installed in such a manner as to view the same portion of the effluent and
where the potential for stratification is due only to air inleakage. Also,
testing to determine the representativeness of a compliance test sampling
location should be conducted in units of the standard.
The only quantitative definition for stratification that is provided in
the existing regulations is contained within Paragraph 3.9, Performance
Specification 2, Appendix B, 40 CFR 60. The definition is as follows:
"3.9 Stratification. A condition identified by a difference in
excess of 10 percent between the average concentration in the duct
or stack and the concentration at any point more than 1.0 meters
from the duct or stack wall."
Paragraph 4.3 of this specification provides the only guidance regarding
the sampling methodology to be used to determine whether stratification exists;
this paragraph reads:
"4.3. The owner or operator may perform a traverse to characterize
any stratification of effluent gases .,, ."
II-4
-------
Thus, stratification testing is performed by making a series of traverse
measurements across the stack or duct sampling location. To determine whether
or not effluent stratification exists as per the above definition, the average
effluent concentration across the stack or duct must also be known during each
measurement made along the stack traverse. Determining the average effluent
concentration concurrent with each traverse point meaurement presents some
difficulties. Ideally, concurrent determinations could be made by
simultaneously measuring emissions at several points along the cross section of
the duct or stack. However, this approach is not feasible because of the
extensive manpower and equipment required to measure spatial stratification.
to ensure that the stratification determination is not affected by temporal
changes in the average effluent concentration, a sampling and calculation
method was developed to eliminate the effects of such temporal variations. This
method employs a dual probe system to sample alternately at a traverse point
and a reference point.
Steady operation is preferable for stratification testing, because the
results are unaffected by incremental effluent concentration shifts caused by
changing process conditions. If stratification testing is performed on sources
operating under batch process conditions, the testing should be conducted
during segments of steady operation.
EQUIPMENT DESCRIPTION
The sampling apparatus necessary for stratification testing is an
extractive continuous monitoring system comprised of the following: a sample
acquisition and gas conditioning system; S0_, CO-, Op, and/or NO monitors;
strip chart recorders; and an automatic data processor (optional). The sample
II-5
-------
acquisition system consists of two heated stainless steel sampling probes, and
the monitoring system is capable of alternately measuring the effluent
extracted through each of the two probes. A detailed description of the
extractive monitoring system, along with its calibration and sampling
procedures, is contained in a document prepared for the EPA, SSCD, entitled,
"Transportable Continuous Emission Monitoring System Operational Protocol" .
SAMPLING PROCEDURE
To eliminate the effects of temporal variations of the average effluent
concentration, all effluent measurements must be noraalizd to a specific point
in time ('t') before the average concentration and percent difference at each
traverse point are calculated; therefore, a dual probe system is used to
measure the effluent emissions. One probe is used as a stationary reference
point placed at the stack or duct centroid during the stratification sampling
period; this probe is used to indicate the temporal change of the effluent
concentrations. The second probe is used for sampling at specified traverse
points determined in accordance with the sampling point location criteria of
Paragraph 3.3-1 of proposed revisions to Performance Specification 2,
Appendix A, 40 CFR 60 (Federal Register. Vol. MU, No. 197, October 10, 1979).
The monitoring system samples at the reference point, traverse point, reference
point, etc., sequentially throughout the testing period for three (3) to five
(5) minutes at each point. The monitoirng system is calibrated with gases
analyzed by the reference methods immediately before and after the
stratification test.
II-6
-------
CALCULATION PROCEDURE
The derivation of the stratification calculation procedure is based on two
principle assumptions:
1. For each traverse point x, there exists a unique constant of
proportionality between the concentrations of the Reference point and
traverse point, such that:
Tx = KXRX
[EQ. 1]
where: T = Concentration at traverse point x
Kx = Proportionality constant for point x
Rx = Reference point concentration
x = 1 , 2, 3. . .
This relationship implies that:
Kx =
[EQ. 2]
2. All changes in effluent concentration occur in such a manner that the
average concentration for a given measurement time interval is
approximately equal to the average of the concentrations measured
before and after that measurement time interval.
Thus, the average Reference concentration at a time when the traverse
point concentration is being measured is equal to the average of the
reference concentrations measured before and after the traverse point
concentration measurement.
Rx = Rxab = Rxb
xa
3]
where: R . = Reference concentration before measurement
of traverse point x
R = Reference concentration after measurement
v a
of traverse point x
In order to compare one traverse point measurement to another on a
consistent basis, the effect of effluent concentration changes with
time must be eliminated. Consequently, all traverse point
measurements must be normalized to some benchmark reference time, t.
II-7
-------
xn
r =
xn
K =
x
R =
R
* t
[EQ. 4]
normalized value of concentration for point x
proportionality constant, defined in EQ. 2
Reference concentration at reference time, t
Equation 4 results in the value that would have been measured for
traverse point x if the reference concentration had been equal to R .
U
Combining EQ. 2 and EQ. 4 and simplifying the resultant normalized
concentration is:
xn
Changes in effluent flow rate or other process operating parameters,
such as failure of a fan, could cause changes in the nature of any
stratification present. This could cause the K values to change,
rendering normalized traverse concentrations inaccurate. Again, this
is only a problem if stratification does exist, and the test will
still (detect this stratification, although it will not accurately
quantify it.
The second assumption may provide a more likely reason for inaccurate
indications of the magnitude of effluent stratification. This
assumption is valid only if the sampling time for each traverse point
is small compared to any cyclic changes in the effluent
concentrations, or if the magnitude of these changes in concentration
is small. As changes in concentration become larger, the assumption
that:
Rx = Rxb + Rxa
becomes more critical . Errors in this assumption become more
pronounced as the measurement time period approaches one-half the time
period of a cyclic concentration change. The most likely result of
such errors is an overestimation of stratification. Thus, the
perviously discussed stratification test procedure will err
conservatively, and indications of no stratification can be viewed
with a high level of confidence.
II-8
-------
STRATIFICATION DATA SHEET
Source and Location
Temporal Chance
Traverse Probe
Reference Probe
22222
Y///////S
W/Y7,
Y//////////////
Y/X//X//X//X//X/////,
-------
TECHNICAL REPORT DATA
(Please read Instructions on the reverse before completing)
1. REPORT NO.
EPA-340/1-83/016
3. RECIPIENT'S ACCESSION NO.
4. TITLE AND SUBTITLE
TRANSPORTABLE CONTINUOUS EMISSION MONITORING SYSTEM
OPERATIONAL PROTOCOL: Instrumental Monitoring of S02,
NOX, C02, and 02 Effluent Concentrations
5. REPORT DATE
January 1983
6. PERFORMING ORGANIZATION CODE
7. AUTHOR(S)
James W.
Peeler
8. PERFORMING ORGANIZATION REPORT NO.
9. PERFORMING ORGANIZATION NAM£ AND ADDRESS
Entropy Environmentalists, Inc.
P.O. Box 12291
Research Triangle Park, NC 27709
10. PROGRAM ELEMENT NO.
11. CONTRACT/GRANT NO.
68-01-6317
12. SPONSORING AGENCY NAME AND ADDRESS
OAQPS
Stationary Source Compliance Division
Waterside Mall, 401 M Street, SW
Washington, DC 20460
13. TYPE OF REPORT AND PERIOD COVERED
FINAL - IN-HOUSE
14. SPONSORING AGENCY CODE
EPA/200/04
15. SUPPLEMENTARY NOTES
16. ABSTRACT
A transportable continuous emission monitoring system (TCEMS) capable of providing
reliable and accurate effluent measurements of S02» NO/NOX, C02, and/or 02 has
been developed and field tested at numerous industrial and utility boilers. This
report presents the operational protocol for the TCEMS, including set-up, opera-
tion, calibration, quality assurance, and data reduction procedures. The TCEMS
and the operational protocol are designed for use in conducting source emission
tests, continuous emission monitor (CEM) relative accuracy tests, and stratifi-
cation tests. Extensive field testing has shown that the TCEMS can be set up,
calibrated, and recording accurate and precise data within two to four hours after
arrival at the site.
7.
KEY WORDS AND DOCUMENT ANALYSIS
DESCRIPTORS
b.lDENTIFIERS/OPEN ENDED TERMS
c. COSATI Field/Group
Air Pollution
Monitoring
Transportable CEMS
Operational Protocol
18. DISTRIBUTION STATEMENT
Release to Public
19. SECURITY CLASS (TIlisReport)
unclassified
21. NO. Or PAGES
72
20. SECURITY_ CLASS (Thispage)
unclassified
22. PRICE
EPA Form 2220-1 (R«v. 4-77) PREVIOUS EDITION is OBSOLETE
------- |