United States
Environments! Protectior
Aaencv
OTM-52: Method for Determination of Combustion
Efficiency from Enclosed Combustors Located at
Oil and Gas Production Facilities
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Other Test Method 52 (OTM-52) Method for Determination of Combustion Efficiency from Enclosed
Combustion Devices Located at Oil and Gas Facilities
Background on OTM-52
The posting of a test method on the Other Test Methods portion of the EMC website is neither an
endorsement by EPA regarding the validity of the test method nor a regulatory approval of the test
method. The purpose of the Other Test Methods portion of the EMC website is to promote discussion
of developing emission measurement methodologies and to provide regulatory agencies, the
regulated community, and the public at large with potentially helpful tools. Other Test Methods have
not yet been subject to the Federal rulemaking process. Each of these methods, as well as the
available technical documentation supporting them, have been reviewed by the EMC staff and have
been found to be potentially useful to the emission measurement community. The types of technical
information reviewed include field and laboratory validation studies; results of collaborative testing;
articles from peer-reviewed journals; peer review comments; and quality assurance (QA) and quality
control (QC) procedures in the method itself. The EPA strongly encourages the submission of
additional supporting field and laboratory data as well as comments regarding these methods.
These methods may be considered for use in federally enforceable State and local programs [e.g., Title
V permits, State Implementation Plans (SIP)] provided they are subject to an EPA Regional SIP
approval process or permit veto opportunity and public notice with the opportunity for comment. The
methods may also be candidates to be alternative methods to meet Federal requirements under 40
CFR Parts 60, 61, and 63. However, they must be approved as alternatives under Parts 60.8, 61.13, or
63.7(f) before a source may use them for this purpose. Consideration of a method's applicability for a
particular purpose should be based on the stated applicability as well as the supporting technical
information. The methods are available for application without EPA oversight for other non-EPA
program uses including state permitting programs and scientific and engineering applications. As
many of these methods are submitted by parties outside the Agency, the EPA staff may not
necessarily be the technical experts on these methods. Therefore, technical support from EPA for
these methods is limited, but the table at the end of this introduction contains contact information for
the authors and developers so that you may contact them directly. Also, be aware that these methods
are subject to change based on the review of additional validation studies or on public comment as a
part of adoption as a Federal test method, the Title V permitting process, or inclusion in a SIP.
The current regulatorily required measurement method for the determination of enclosed combustion
device (ECD) control efficiencies is both costly and complex to implement. The current reference
method is a mass balance approach that requires high-cost instrumentation and inlet and outlet flow
rate measurements to determine destruction and removal efficiency from ECDs. Many of these ECDs
are located at remote locations, are note equipped with inlet and outlet measurement ports and can
operate intermittently which present significant logistical and technical challenges that further
complicate use. Alternatively, this method determines combustion efficiency (CE) using a volumetric-
based approach that does not require flowrate measurements and can employ a range of
measurement technologies from lower cost sensor packages to high performance instruments. This
lower cost "outlet only" test method can be flexibly applied to achieve testing objectives ranging from
quick operational checks to higher accuracy assessments with effective performance levels
comparable to existing reference methods. Future iterations of this method will increase the accuracy
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
of the measurements through the continued development of site-specific waste-gas speciation
correction factors. Overall, OTM-52 reduces implementation burden and minimizes potential errors
associated with the current reference method.
Posting this method, in and of itself, does not establish a requirement, although the use of this
method may be specified by the EPA or a state through independent actions. Terms such as "must" or
"required," as used in this document, refer to procedures that are to be followed to conform with the
method. References to specific brands and catalog numbers are included only as examples and do not
imply endorsement of the products. Such reference does not preclude the use of equivalent products
from other vendors or suppliers.
OTM 52 is a draft method under evaluation that will be updated as more data from stakeholders
becomes available. Due to the urgent need for a cost effective and easy to implement method to
determine ECD control efficiencies, this method is being released as an "Other Test Method (OTM)" by
EPA's Emission Measurements Center. We solicit any and all feedback, comments, and additional data
coming from the application of this method as we work to adjust this method in anticipation of
developing a reference method for the determination of combustion efficiency from ECDs located at
oil and gas facilities.
Note: Please submit a copy, either electronic or paper, of any test report from application of this OTM
to EPA's Measurement Technology Group.
• Electronic copies should be submitted via email with the subject line "OTM-052" to:
EMC@epa.gov
• Paper copies should be mailed to:
Measurement Technology Group
Office of Air Quality Planning and Standards
U.S. Environmental Protection Agency (Mail Code E143-02)
Research Triangle Park, NC 27711
OTM-52 Authors and Developers
Michael Stovern*
R8/ECAD/ATB
Stovern.Michael@epa.gov
Jared Beck
WYDEQ/AQD
Jared.Beck@wyo.gov
Eben Thoma
ORD/CEMM/AMCD/SFSB
Thoma.Eben@epa.gov
* Primary contact
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Other Test Method 52 (OTM-52) Method for Determination of Combustion Efficiency from Enclosed
Combustion Devices Located at Oil and Gas Facilities
1.0 Scope and Application
Other Test Method (OTM)-52 is a test method for measuring combustion efficiency from
enclosed combustion devices located at oil and gas facilities. Quality assurance and quality
control (QA/QC) requirements are included to assure that you, the tester, collect data of
known and acceptable quality for each testing program. OTM-52 does not completely describe
all equipment, supplies, and sampling and analytical procedures you will need, but instead
refers to supporting test methods for some of the details. Use of OTM-52 requires a thorough
knowledge of the additional test methods referenced below, which are found in 40 CFR Part
60, Appendices A-2, A-4 and A-7:
(a) Method 3A - Determination of Oxygen and Carbon Dioxide Concentrations in
Emissions from Stationary Sources2
(b) Method 7E - Determination of Nitrogen Oxides Emissions from Stationary Sources
(Instrumental Analyzer Procedure)3
(c) Method 10 - Determination of Carbon Monoxide Emissions from Stationary
Sources4
(d) Method 25A - Determination of Total Gaseous Organic Concentration Using a
Flame Ionization Analyzer5
(e) Method 25B - Determination of Total Gaseous Organic Concentration Using a
Nondispersive Infrared Analyzer6
(f) Method 320 - Measurement of Vapor Phase Organic and Inorganic Emissions by
Extractive Fourier Transform Infrared (FTIR) Spectroscopy7
1.1 Analytes.
This method measures the concentrations of carbon dioxide (C02), carbon monoxide
(CO), hydrocarbon concentration (HCC), and oxygen (02) as determined using
established federal reference methods.
Table 1-1 Analyte list
Analyte
CAS No
Sensitivity
Carbon Dioxide (C02)
124-38-9
< 2% of Calibration Span Gas Value
Carbon Monoxide (CO)
630-08-0
< 2% of Calibration Span Gas Value
Hydrocarbon Concentration (HCC)*
N/A
< 2% of Calibration Span Gas Value
Oxygen (02)
7782-44-7
< 2% of Calibration Span Gas Value
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
* See Appendix B for a list of target analytes for determination of HCC when using
Method 320
1.2 Applicability.
This method is intended for the measurement of combustion efficiency using C02, CO,
HCC and 02 in enclosed combustors located at oil and gas production facilities for the
purposes of conducting performance tests to demonstrate compliance with applicable
performance standards. The use of this method for performance tests used to
demonstrate compliance with federal emissions standards or monitoring
requirements must be approved by the EPA Administrator. This method is available,
with appropriate administrative oversight, for application without Federal oversight
for other non-federal program uses including state permitting programs and
engineering applications.
1.3 Data Quality Objectives (DQO).
This method is designed to provide high-quality data for the determinations described
above. In these and other applications, the principal objective is to ensure data
accuracy that the emission levels are at or below the emissions target. To meet this
objective, the use of EPA traceability protocol calibration gases and measurement
system performance tests are required.
2.0 Summary of Method
A gas sample is continuously extracted from the exhaust duct of an enclosed combustion
device and conveyed to the specific gas analyzer(s) for determination of C02, CO, and HCC gas
concentrations for the calculation of combustion efficiency. You must meet the design
specifications, analyzer performance requirements, and test procedures of this method and
referenced methods to ensure reliable performance. Note: This method does not incorporate
technology specific characteristics and is technology neutral. The concentration measurement
device may be referred to as a "gas analyzer", a "sensor", or an "instrument", with these
terms used interchangeably in this method. The analyte concentrations used in calculation of
combustion efficiency (see 12.9) can be done on either a wet or dry basis, it just needs to be
consistent across all analytes and as specified in the applicable regulation, permit or other
requirement.
3.0 Definitions
3.1 Ambient Air Rinse means the gas analyzer sample stream is ambient air. This occurs for a
set amount of time between measurements. It is also referred to as purging, breathing, or
rinsing. It is required between the introduction of each analyte calibration gas during system
verification and between sample runs for emissions tests.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
3.2 Calibration Error means the percentage difference between the gas concentration
measured by the gas analyzer and the known concentration of the calibration gas.
3.3 Calibration Gas means a gas mixture containing an analyte at a known concentration and
produced and certified in accordance with "EPA Traceability Protocol for Assay and
Certification of Gaseous Calibration Standards/' September 1997, as amended May 2012, EPA-
600/R-12/5311 or more recent updates. The system verification tests require the use of
calibration gas prepared according to this protocol. In the absence of reference materials to
which a protocol gas may be made traceable, implementors of this method may follow ALT-
105 or ALT-114, as appropriate, to generate the calibration gases needed for use with this
method.
3.3.2 High-Level Gas means a calibration gas with a concentration that is equal to the
Calibration Span.
3.3.3 Mid-level Calibration Gas means a calibration gas with a concentration
equivalent of 40 to 60 percent of the Calibration Span.
3.3.4 Low-level Calibration Gas means a calibration gas with a concentration
equivalent to <20 percent of the Calibration Span.
3.4 Calibration Span means the upper limit of the analyzer's calibration that is set by the
choice of high-level calibration gas. No valid run average concentration may exceed the
calibration span. To the extent practicable, the measured emissions should be between 20 to
100 percent of the selected calibration span. This may not be practicable in some cases of low-
concentration measurements or testing for compliance with an emission limit when emissions
are substantially less than the limit. In such cases, calibration spans that are practicable to
achieving the test DQOs without being excessively high should be chosen.
3.5 Direct Calibration Mode means introducing the calibration gases directly into the analyzer
(or into the assembled measurement system at a point downstream of all sample conditioning
equipment) according to manufacturer's recommended calibration procedure. This mode of
calibration applies to non-dilution-type measurement systems.
3.6 Drift means the difference between the pre- and post-run system bias (or system
calibration error) checks at a specific calibration gas concentration level (i.e., low-, mid-, or
high-).
3.7 Measurement System means all equipment used to determine the HCC, CO, and C02
concentrations. The measurement system comprises six major subsystems: sample
acquisition, sample transport, sample conditioning, calibration gas manifold, gas analyzer(s),
and data recorder(s).
3.8 Sensor Response Time means the time it takes the sensor to respond to a change in gas
concentration at the analyzer while the sampling system is operating normally at its target
sample flow rate or dilution ratio.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
3.9 Stability Check means the procedure for demonstrating that a sensor response to the
calibration gas provides a stable output.
3.10 System Bias means the difference between a calibration gas measured in direct
calibration mode and in system calibration mode. System bias is determined before and after
each run at the low- and mid- or high-concentration levels. For dilution-type systems, pre- and
post-run system calibration error is measured rather than system bias.
3.11 System Calibration Error applies to dilution-type systems and means the difference
between the measured concentration of low-, mid-, or high-level calibration gas and the
certified concentration for each gas when introduced in system calibration mode. For dilution-
type systems, a 3-point system calibration error test is conducted in lieu of the analyzer
calibration error test, and 2-point system calibration error tests are conducted in lieu of
system bias tests.
3.12 System Calibration Mode means introducing the calibration gases into the measurement
system at the probe, upstream of the filter and all sample conditioning components.
3.13 System Response Time means the time it takes the measurement system to respond to a
change in gas concentration occurring at the sampling point when the system is operating
normally at its target sample flow rate or dilution ratio.
3.14 Test Run means a series of gas samples taken successively from the stack or duct for a
duration of 60 minutes, unless otherwise specified by a permitting authority.
4.0 Interferences
Note that interferences may vary among instruments and that instrument-specific
interferences must be evaluated consistent with their respective method (e.g. Method 320
Section 4.0).
5.0 Safety
This method may require you to work with hazardous materials and in hazardous conditions.
We encourage you to establish safety procedures before using the method. Among other
precautions, you should become familiar with the safety recommendations in the gas analyzer
user's manual. Occupational Safety and Health Administration (OSHA) regulations concerning
cylinder and noxious gases may apply. All calibration gases must be handled with utmost care
and with adequate ventilation.
6.0 Equipment and Supplies
The performance criteria in this method will be met or exceeded if you are properly using
equipment designed for this application.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
6.1 What do I need for the measurement system?You may use any measurement system that
meets the performance and design standards within this method and the following equipment
and supply specifications:
6.1.1 Sampling system components that are not evaluated in the system bias or
system calibration error test must be glass, Teflon, or stainless steel. Other materials
are potentially acceptable, subject to approval by the EPA Administrator.
6.1.2 The instrumental analyzers must meet the analyzer performance requirements
in Table 9-1.
6.2 Measurement System Components
6.2.1 Sample Probe. Glass, stainless steel, or other non-reactive material of sufficient
length to sample from the centrally located 10 percent area of the stack cross-section.
6.2.2 Particulate Filters. An in-stack or out-of-stack filter. The filter must be made of
material that is non-reactive to the gas being sampled. The filter media for out-of-
stack filters must be included in the system bias test. The particulate filter
requirement may be waived in applications where no significant particulate matter is
expected (e.g., for emission testing of a combustion turbine firing natural gas).
6.2.3 Sample Line. The sample line from the probe to the conditioning system/sample
pump should be made of Teflon or other material that does not absorb or otherwise
alter the sample gas.
6.2.4 Conditioning Equipment. For dry basis measurements, a condenser, dryer, or
other suitable device is required to remove moisture continuously from the sample
gas. Any equipment needed to heat the probe or sample line to avoid condensation
prior to the sample conditioning component is also required.
6.2.5 Sample Pump. A leak-free pump is needed to pull the sample gas through the
system at a flow rate sufficient to minimize the system response time of the
measurement system. The pump may be constructed of any material that is non-
reactive to the gas being sampled. For dilution-type measurement systems, an
ejector pump (eductor) is used to create a vacuum that draws the sample through
a critical orifice at a constant rate.
6.2.6 Calibration Gas Manifold. Prepare a system to allow the introduction of
calibration gases either directly to the gas analyzer(s) in direct calibration mode or
into the measurement system, at the probe, in system calibration mode, or both,
depending upon the type of system used. In system calibration mode, the system
should be able to flood the sampling probe and vent excess gas. Alternatively,
calibration gases may be introduced at the calibration valve following the probe.
Maintain a constant pressure in the gas manifold. For in-stack dilution-type systems, a
gas dilution subsystem is required to transport large volumes of purified air to the
sample probe and a probe controller is needed to maintain the proper dilution ratio.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
For Method 320 analyzers an analyte spike assembly must be included that also
includes a mass flow meter that is used to measure analyte spike flow.
6.2.7 Sample Gas Manifold. For the type of system shown in Figure 7E-13, the sample
gas manifold diverts a portion of the sample to the analyzer(s), delivering the
remainder to the by-pass discharge vent. The manifold should also be able to
introduce calibration gases directly to the analyzer(s) (except for dilution-type
systems). The manifold must be made of material that is non-reactive to the gas
sampled or the calibration gas and be configured to safely discharge the bypass gas.
6.2.8 Gas Analyzer(s).
6.2.8.1 C02 Concentration Analyzer (Method 3A)2. You must use an analyzer
that continuously measures C02 in the gas stream and capable of meeting or
exceeding the specifications of this method and the analyzer performance
requirements in Table 9-1.
6.2.8.2 CO Concentration Analyzer (Method 10)4. You must use an instrument
that continuously measures CO in the gas stream and capable of meeting or
exceeding the specifications of this method and the analyzer performance
requirements in Table 9-1.
6.2.8.3 Organic Concentration Analyzer (Method 25A)5. You must use a flame
ionization analyzer (FIA) capable of meeting or exceeding the specifications of
this method and the analyzer performance requirements in Table 9-1.
6.2.8.4 Organic Concentration Analyzer (Method 25B)6. You must use a
nondispersive infrared (NDIR) analyzer designed to measure alkane organics
and capable of meeting or exceeding the specifications in this method and the
analyzer performance requirements in Table 9-1.
6.2.8.5 Organic Concentration Analyzer (Method 320)7. You must use a FTIR
analytical system designed to measure alkane organics and capable of
meeting or exceeding the specifications in this method and the analyzer
performance requirements in Table 9-1. For sampling systems that will utilize
FTIR to quantify HCC, they must meet all QA/QC requirements within both this
OTM and Method 320.
6.2.9 Data Recorder. A computerized data acquisition system, digital recorder, or data
logger for recording measurement data may be used. The minimum data recording
requirement is one measurement value per minute.
7.0 Reagents and Standards
7.1 Calibration Gases.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
The calibration gases for the gas analyzer shall be C02 in nitrogen (N2) or C02 in
synthetic air; CO in N2 or CO in synthetic air; and methane (CH4) in N2 or CH4 in
synthetic air. Each calibration gas must be certified (or recertified) within an
uncertainty of 2.0 percent in accordance with "EPA Traceability Protocol for Assay and
Certification of Gaseous Calibration Standards" September 1997, as amended May
2012, EPA-600/R-12/5311. In the absence of reference materials to which a protocol
gas may be made traceable, implementors of this method may follow ALT-105, as
appropriate, to generate the calibration gases needed for use with this method. Zero
gas must meet the requirements under the definition for "zero air material" in 40 CFR
72.2. The calibration gas must be used before its expiration date and the cylinder gas
pressure must be greater than the minimum pressure of use. It is acceptable to
prepare calibration gas mixtures from EPA Traceability Protocol gases in accordance
with Method 205 in appendix M to 40 CFR Part 51. The following calibration gas
concentrations are required:
7.1.1 High-Level Gas. This concentration is chosen to set the calibration span as
defined in Section 3.4.
7.1.2 Mid-Level Gas. 40 to 60 percent of the calibration span.
7.1.3 Low-Level Gas. Less than 20 percent of the calibration span.
7.1.4 Zero Gas. High purity air with less than 0.1 part per million by volume (ppmv) of
organic material (propane or carbon equivalent) or less than 0.1 percent of the span
value, whichever is greater.
7.1.5 Fuel for Method 25A analyzer (if applicable). A 40 percent hydrogen (H2)/60
percent N2gas mixture is recommended to avoid an oxygen synergism effect that
reportedly occurs when oxygen concentration varies significantly from a mean value.
7.1.5 Tracer/Spike gas (Method 320 analyzer only). If practical, the analyte standard
cylinder shall also contain the tracer gas at a concentration which gives a measurable
absorbance at a dilution factor of at least 10:1. Two ppm SF6 is sufficient for a path
length of 22 meters at 250 °F.
7.2 Reference Spectra (Method 320 analyzer only). Obtain reference spectra for each analyte,
interferant, surrogate, CTS, and tracer. If EPA reference spectra are not available, use
reference spectra prepared according to procedures in section 4.6 of the EPA FTIR Protocol.
8.0 Sample Collection, Preservation, and Storage Emission Test Procedure:
This following section includes all required sampling and analysis procedures required for
measurements collected using Method 3A, 10, 25A and 25B analyzers. For measurements
utilizing a Method 320 analyzer the user shall follow all requirements in Method 320 as well as
OTM-52 Sections 8.1, 8.2.1, 8.2.8, 8.4 and 8.6.
8.1 Sampling Location.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
The sampling probe shall be centrally located in the stack and at least 0.5 duct
diameters into the stack.
8.2 Initial Measurement System Performance Tests.
Before measuring emissions, you must perform the procedures:
(a) Calibration Gas Verification (8.2.1)
(b) Measurement System Preparation (8.2.2)
(c) Leak Check (8.2.3)
(d) Calibration Error Test (8.2.4)
(e) Stability Check (8.2.5)
(f) System and Sensor Response Time (8.2.6)
(g) Initial System Bias Check (8.2.7)
(h) Ambient Background Concentration (8.2.8)
8.2.1 Calibration Gas Verification.
Obtain a certificate from the gas manufacturer documenting the specifications
of the gas blend. Confirm that the manufacturer certification is complete and
current. Ensure that your calibration gas certifications have not expired. This
documentation should be available on-site (i.e., test location) for inspection.
To the extent practicable, select a high-level gas concentration that will result
in the measured emissions being between 20 and 100 percent of the
calibration span values.
8.2.2 Measurement System Preparation.
Assemble, prepare, and precondition the measurement system according to
your standard operating procedure. Conduct an initial calibration of all
analyzers per the manufacturer(s) directed calibration procedures. Adjust the
system to achieve the correct sampling rate or dilution ratio (as
applicable).
8.2.3 Leak Check.
After you have assembled, prepared, and calibrated your sampling system and
analyzer, you must conduct a leak check by injecting an oxygen free gas
through the sampling probe tip and verifying that the 02 reading is less than or
equal to 0.2 percent; record the result of the check.
8.2.4 Calibration Error Test.
After you have assembled, prepared, and calibrated your sampling system
and analyzer(s), you must conduct a 3-point analyzer calibration error test
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
(or a 3-point system calibration error test for dilution systems) before the
first run. Introduce the low-, mid-, and high-level calibration gases
sequentially. For non-dilution-type measurement systems, introduce the
gases in direct calibration mode. For dilution-type measurement systems,
introduce the gases in system calibration mode.
(1) For non-dilution systems, you may adjust the system to maintain the
correct flow rate at the analyzer(s) during the test, but you may not make
adjustments for any other purpose. For dilution systems, you must operate
the measurement system at the appropriate dilution ratio during all system
calibration error checks and may make only the adjustments necessary to
maintain the proper ratio.
(2) Record the analyzer's response to each calibration gas on a form similar to
Table OTM-52-1. For each calibration gas, calculate the analyzer calibration
error using Equation OTM-52-1 in section 12.2 or the system calibration error
using Equation OTM-52-3 in section 12.4 (as applicable). The calibration error
specification in section 13.1 must be met for the low-, mid-, and high-level
gases. If the calibration error specification is not met, take corrective action
and repeat the test until an acceptable 3-point calibration is achieved.
(3) This test remains valid for 5 days or until a sensor has been replaced.
(4) Repeat section 8.2.4 (Calibration Error Test) for each target analyte (i.e.,
C02, CO, HCC, and 02).
8.2.5 Stability Check.
8.2.5.1 Procedure. Inject the span gas into the analyzer and record the
analyzer response at least once per minute until the conclusion of the test.
One-minute average values may be used instead of instantaneous readings.
After the analyzer response has stabilized, continue to flow the span gas for at
least 30 minutes. Make no adjustments to the analyzer during the test except
to maintain constant flow. Record the "time to stabilize" as the number of
minutes elapsed between the start of the gas injection and the start of the 30-
minute stability check period. If the concentration reaches a peak value within
five minutes, you may choose to record the data for at least 15 minutes
following the peak.
8.2.5.2 Calculations. Determine the highest and lowest concentrations
recorded during the 30-minute period and record the results on a form similar
to Table OTM-52-2.
8.2.5.3 This test remains valid for 5 days or until a sensor has been replaced.
8.2.5.4 Repeat section 8.2.5 (Stability Check) for each target analyte (i.e., C02,
CO, HCC, and 02)
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
8.2.6 System and Sensor Response Times.
Introduce the calibration span gases at the probe upstream of all sample
conditioning components in the system. Determine system response time by
recording the time it takes for the calibration span gas introduced at the
probe to cause the measured concentration to increase to a value that is at
least 95 percent or within 0.5 ppmv (whichever is less restrictive) of a stable
response for the span gas. Continue to observe the gas concentration reading
until it has reached a final, stable value and then perform an ambient rinse.
Sensor response time is determined by the time it takes for only the sensor to
increase to a value that is at least 95 percent or within 0.5 ppmv (whichever is
less restrictive) of a stable response for the span gas. Sensor response time
does not include sampling train time and should start when the sensor first
shows a response to the calibration gas. Sensor response time must be two
minutes or less.
Note that system and sensor response times can be done during the 2-point
system bias check.
Repeat section 8.2.6 (System and Sensor Response Times) for each target
analyte sensor/analyzer (i.e., C02, CO, HCC, and 02)
8.2.7 Initial System Bias Check.
8.2.7.1 Before sampling begins, determine whether the high or mid-level
calibration gas best approximates the emissions and use it as the upscale gas.
Introduce the upscale gas at the probe upstream of all sample conditioning
components in system calibration mode. Record the time it takes for the
measured concentration to increase to a value that is at least 95 percent or
within 0.5 ppmv (whichever is less restrictive) of a stable response for the
upscale gases. Continue to observe the gas concentration reading until it has
reached a final, stable value. Record this value on a form similar to Table
OTM-52-3.
8.2.7.2 Next, introduce the low-level gas in system calibration mode and
record the time required for the concentration response to decrease to a
value that is within 5.0 percent or 0.5 ppmv (whichever is less restrictive) of
the certified low-range gas concentration. If the low-level gas is a zero gas, use
the procedures described above and observe the change in concentration
until the response is 0.5 ppmv or 5.0 percent of the upscale gas concentration
(whichever is less restrictive).
8.2.7.3 Continue to observe the low-level gas reading until it has reached a
final, stable value and record the result on a form similar to Table OTM-52-3.
Operate the measurement system at the normal sampling rate during all
system bias checks. Make only the adjustments necessary to achieve proper
calibration gas flow rates at the analyzer.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
8.2.7.4 From this data, calculate the measurement system response time (see
section 8.2.5) and then calculate the initial system bias using Equation OTM-
52-2 in section 12.3. For dilution systems, calculate the system calibration
error in lieu of system bias using Equation OTM-52-3 in section 12.4. See
Section 9, Table 9-1 for acceptable performance criteria for system bias. If the
initial system bias (or system calibration error) specification is not met, take
corrective action. Then, you must repeat the applicable initial system bias (or
2-point system calibration error) check until acceptable results are achieved,
after which you may begin sampling.
8.2.7.5 Repeat section 8.2.7 (Initial System Bias Check) for each target analyte
(i.e., C02, CO, HCC, and 02)
8.2.8 Ambient Background Concentration.
Before sampling begins, determine the ambient background concentrations of
each analyte. Collect and record background concentrations for at least four
times the system response time.
8.3 Dilution-Type Systems—Special Considerations.
When a dilution-type measurement system is used, there are three important
considerations that must be taken into account to ensure the quality of the emissions
data. First, the critical orifice size and dilution ratio must be selected properly so that
the sample dew point will be below the sample line and analyzer temperatures.
Second, a high-quality, accurate probe controller must be used to maintain the
dilution ratio during the test. The probe controller should be capable of monitoring
the dilution air pressure, eductor vacuum, and sample flow rates. Third, differences
between the molecular weight of calibration gas mixtures and the stack gas molecular
weight must be addressed because these can affect the dilution ratio and introduce
measurement bias.
8.4 Sample Collection Method.
8.4.1 Position the sampling probe at the centroid of the stack and begin sampling.
Purge the system for a duration of at least two times the system response time before
recording any data. Maintain the appropriate sample flow rate or dilution ratio (as
applicable). You must record at least one data point per minute during the test run.
8.4.2 A test run shall be 60 minutes in duration.
8.4.3 At the conclusion of each test run, perform the ambient air rinse for a minimum
of five minutes. The duration of the ambient air rinse must be sufficient to refresh the
sensor to a zero or background concentration-reading state. The amount of time for
the ambient air rinse is generally dependent upon the gas concentration and the
duration of sampling at elevated gas concentrations.
8.5 Post-Run System Bias Check and Drift Assessment
14
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
8.5.1 After each run, repeat the system bias check or 2-point system calibration error
check to validate the run. Do not make adjustments to the measurement system
(other than to maintain the target sampling rate or dilution ratio) between the end of
the run and the completion of the post-run system bias or system calibration error
check. Note that for all post-run system bias or 2-point system calibration error
checks, you may inject the low-level gas first and the upscale gas last, or vice-versa.
You must perform a post-run system bias or system calibration error check after each
individual test run.
8.5.2 If you do not pass the post-run system bias (or system calibration error) check,
then the test run is invalid. You must diagnose and fix the problem and pass another
system bias (or 2-point system calibration error) check (Section 8.2.7) before
repeating the test run. Record the system bias (or system calibration error) results on
a form similar to Table OTM-52-3.
8.5.3 After each test run, calculate the low-level and upscale drift, using Equation
OTM-52-4 in section 12.5. If the post-run low- and upscale bias (or 2-point system
calibration error) checks are passed, but the low-or upscale drift exceeds the
specification in section 9.0, the test run data are valid, but a 3-point calibration error
test and a system bias (or 2-point system calibration error) check must be performed
and passed before any more test runs are performed.
8.5.4 For dilution systems, data from a 3-point system calibration error test may be
used to meet the pre-run 2-point system calibration error requirement for the first
test run in a test sequence. Also, the post-run bias (or 2-point calibration error) check
data may be used as the pre-run data for the next run in the test sequence at the
discretion of the tester.
8.6 Post-Run Duty Cycle Assessment
After each run, an assessment of duty cycle must be completed to determine if the
enclosed combustion device was operating for a sufficient period during the run to
have valid results. Each data point (<1 minute average) will need to be evaluated to
determine if the combustion device was operational. For each data point, if either the
measured C02 (corrected to remove background, bias, and drift) or HCC (corrected to
remove background, bias, and drift) exceeds two times the background concentration
(measured as required in 8.2.8), the control device is deemed to be operational for
that data point. For the HCC sensor with the background concentration measured as
zero per 8.2.8, the concentration threshold to determine operational status is five
times the sensor's minimum resolution.
When using Method 320, follow OTM-52 Appendix B for the determination of HCC
and C02 in the ambient background samples and during each data point during the
test run. Then complete the duty cycle assessment above.
15
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
9.0 Quality Assurance and Quality Control
Table 9-1 summarizes the QA/QC performance criteria.* The Status column indicates if the
criteria is either Suggested (S), Mandatory (M), or is an Alternative (A).
Regarding Section 8.6 "Post-Run Duty Cycle Assessment", see Table OTM-52-4 for required
duty cycles based on HCC sensor minimum resolution. Also, the entire run is invalid if any test
run that does not meet the required duty cycle from Table OTM-52-4.
*Tests utilizing Method 320 analyzer for analyte quantification must meet all QA/QC
requirements within Method 320 Section 9 in addition to the applicable QA/QC requirements
within this Section.
Table 9-1. Quality Assurance/Quality Control Criteria
Status
Process or
Element
QA/QC
Specification
Acceptance Criteria
Checking Frequency
s
Analyzer
design
Analyzer resolution
or sensitivity
<2.0% of full-scale range
Manufacturer
design
M
Analyzer
design
Analyzer sensor
minimum
resolution
Carbon dioxide (Method
3a) -0.1%;
Carbon monoxide (Method
10) - 0.01 %;
Hydrocarbon Concentration
(Method 25a or 25b)-0.01
%;
Manufacturer
design.
M
Calibration
gases
Traceability
protocol
Valid certificate required
uncertainty <2.0% of tag
value
Each test
M
High-level gas
Equal to calibration span
M
Mid-level gas
40-60% of calibration span
M
Low-level gas
<20% of calibration span
S
Data Recorder
Design
Data resolution
<0.5% of full-scale range
Manufacturer
design
S
Sample
Extraction
Probe material
Stainless steel or quartz if
stack >500 °F
Each test
M
Sample
Extraction
Probe, filter, and
sample line
temperature
1) For dry-basis analyzers,
keep sample above the
dew point by heating, prior
to sample conditioning
Each test
2) For wet-basis analyzers,
keep sample above dew
point at all times, by
heating or dilution
Each test
S
Sample
Extraction
Calibration valve
material
Stainless steel
Each test
S
Sample
Extraction
Sample pump
material
Inert to sample
constituents
Each test
16
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
s
Sample
Manifolding
Inert to sample
Each test
Extraction
material
constituents
s
Moisture
Equipment
<5% target compound
Verified through
Removal
efficiency
removal
system bias check
s
Particulate
Removal
Filter inertness
Pass system bias check
Each bias check
M
Analyzer &
Analyzer calibration
Within ±2.5 percent of the
Before initial run
Calibration Gas
error test (or 3-
calibration span of the
and after a failed
Performance
point system
analyzer for the low-, mid-,
system bias test or
calibration error for
and high-level calibration
drift test
dilution systems)
gases
A
Alternative specification:
<0.5 ppmv absolute
difference
M
System
System bias (or pre-
Within ±5.0% of the
Before and after
Performance
and post-run 2-
point system
calibration error for
dilution systems)
analyzer calibration span
for low-scale and upscale
calibration gases
each run
A
Alternative specification:
<0.5 ppmv absolute
difference
M
System
System response
Determines minimum
During initial
Performance
time
sampling time per point
sampling system
bias test
M
System
Sensor response
<2 min
During initial
Performance
time
sampling system
bias test
M
System
Performance
Drift
<3.0% of calibration span
for low-level and mid- or
high-level gases
After each test run
A
Alternative specification:
<0.5 ppmv absolute
difference
M
System
Purge time
>2 times system response
Before starting the
Performance
time
first run and when
probe is removed
from and re-
inserted into the
stack
M
System
Performance
Stability Test
The difference between the
maximum and minimum
values recorded during the
30-minute period must be
less than 2.0% of the span
gas concentration
Once every 5 days
17
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Alternatively, the
difference between the
maximum and minimum
values recorded during the
15-minute period must be
less than 1.0% percent of
the span gas concentration
M
System
Stable sample flow
Within 10% of flow rate
Each run
Performance
rate (surrogate for
maintaining system
response time)
established during system
response time check
M
Data
Recording
Frequency
<1 minute average
During each test run
S
Data
Sample
All 1-minute averages
Each test run
Parameters
concentration
range
within 125% of calibration
span
M
Data
Average
Test run average
Each test run
Parameters
concentration for
the run
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
11.0 Analytical Procedures
For measurements collected using Method 3A, 10, 25A and 25B analyzers, because sample
collection and analysis are performed together (see Section 8), additional discussion of the
analytical procedure is not necessary.
For measurements collected using a Method 320 analyzer, analytical procedures outlined in
Method 320 and OTM-52 Appendix B must be followed.
12.0 Calculations and Data Analysis
You must follow the procedures for calculations and data analysis listed in this section.
Tests utilizing Method 320 with an FTIR analyzer for analyte quantification must follow the
procedures within OTM-52 Appendix B, Method 320 Section 11, Method 320 Section 13 as
well as the following sections: OTM-52 Sections 12.7, 12.10 and 12.11.
12.1 Nomenclature.
The terms used in the equations are defined as follows:
ACE = Analyzer calibration error, percent of calibration span.
CAvg = Average unadjusted gas concentration indicated by data recorder for the test
run, ppmv.
Ceack = Average ambient background concentration, ppmv.
CDir = Measured concentration of a calibration gas (low, mid, or high) when introduced
in direct calibration mode, ppmv.
CGas = Average effluent gas concentration adjusted for bias, ppmv.
Cco2 = Average carbon dioxide gas concentration adjusted for bias, ppmv.
Ceo = Average carbon monoxide gas concentration adjusted for bias, ppmv.
Chcc = Average hydrocarbon gas concentration adjusted for bias, ppmv.
CM = Average of initial and final system calibration bias (or 2-point system calibration
error) check responses for the upscale calibration gas, ppmv.
Cma = Actual concentration of the upscale calibration gas, ppmv.
C0 = Average of the initial and final system calibration bias (or 2-point system
calibration error) check responses from the low-level (or zero) calibration gas, ppmv.
Cqa = Actual concentration of the low-level calibration gas, ppmv.
19
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Cs = Measured concentration of a calibration gas (low, mid, or high) when introduced
in system calibration mode, ppmv.
Cv = Manufacturer/vendor certified concentration of a calibration gas (low, mid, or
high), ppmv.
CE% = Combustion efficiency percentage
CS = Calibration span, ppmv.
D = Drift assessment, percent of calibration span.
DC = Duty cycle of ECD operation during test period
DF = Dilution system dilution factor or spike gas dilution factor, dimensionless.
Ndc = is the number of data points that meets the definition of ECD operation (See
12.11).
NSp = is the number of data points in the entire test period.
SB = System bias, percent of calibration span.
SB, = Pre-run system bias, percent of calibration span.
SBfinai = Post-run system bias, percent of calibration span.
SCE = System calibration error, percent of calibration span.
SCEi = Pre-run system calibration error, percent of calibration span.
SCEFinai = Post-run system calibration error, percent of calibration span.
12.2 Analyzer Calibration Error.
For non-dilution systems, use Equation OTM-52-1 to calculate the analyzer calibration
error for the low-, mid-, and high-level calibration gases.
12.3 System Bias.
For non-dilution systems, use Equation OTM-52-2 to calculate the system bias
separately for the low-level and upscale calibration gases.
ACE = Cmr Cv x 100
cs
Eq. OTM-52-1
SB = cs cDir
cs
Eq. OTM-52-2
20
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
12.4 System Calibration Error.
Use Equation OTM-52-3 to calculate the system calibration error for dilution systems.
Equation OTM-52-3 applies to both the initial 3-point system calibration error test and
the subsequent 2-point calibration error checks between test runs. In this equation,
the term "Cs" refers to the diluted calibration gas concentration measured by the
analyzer.
SCE = (,csxdf)-cv OTM-52-3
cs ^
12.5 Drift Assessment.
Use Equation OTM-52-4 to separately calculate the low-level and upscale drift over
each test run. For dilution systems, replace "SBfinai" and "SB" with "SCEfinai" and "SCE",
respectively, to calculate and evaluate drift.
D = \SBfinal - SBi\ Eq. OTM-52-4
12.6 Effluent Gas Concentration (Methods 3A, 10, 25A and 25B).
For each test run, calculate Cavg, the arithmetic average of all valid analyte
concentration values (ppmv). Then adjust the value of Cavg (ppmv) for bias using
Equation OTM-52-5a if you use a non-zero gas as your low-level calibration gas, or
Equation OTM-52-5b if you use a zero gas as your low-level calibration gas.
Caas = (Cavg ~ CBack " CM) + Cam Eq. OTM-52-5a
Caas = (Cavg ~ CBack " C0) Eq. OTM-52-5b
Cc02 = CGas(C02) Cco = CGas(-C0) CT0c = CGas(HCQ
12.7 Effluent Gas Concentration (Method 320)
For tests using Method 320 with an FTIR analyzer, Use OTM-52 Appendix B to
determine average test-run concentrations of HCC, C02 and CO. Then follow the bias
and correction factor approaches identified in Method 320, Section 13.4 to correct the
analytically derived gas concentrations in lieu of the approach above. Then determine
Chcc, CCo2 and CCo by subtracting the background concentration of the analyte from
the bias corrected average test run concentration.
12.8 Method 25A Response Factor Correction
If Chcc is determined using Method 25A a FID response factor correction needs to be
applied. The generic response factor (RF) is equal to 1.28. In lieu of using the generic
21
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
response factor, an analyzer specific response factor can be developed by following
the procedure in Appendix A of this method and can be used in place of 1.28.
CT0C = 1.28 * CGas(HCC) Eq. OTM-52-6
12.9 Method 25B Response Factor Correction
If Chcc is determined using Method 25B a NDIR response factor correction needs to be
applied. The generic response factor (RF) is equal to 0.44. In lieu of using the generic
response factor, an analyzer specific response factor can be developed by following
the procedure in Appendix A of this method and can be used in place of 0.44.
CT0C = 0.44 * CGas(HCC) Eq. OTM-52-7
12.10 Combustion Efficiency.
Use Equation OTM-52-8 to calculate the combustion efficiency of the enclosed
combustor.
CE% = ^22 * 100 Eq. OTM-52-8
(CC02 +CCO +CHCC)
Note: The analyte concentrations used in calculation of combustion efficiency can be
done on either a wet or dry basis, it just needs to be consistent across all analytes.
12.11 Duty Cycle
Use Equation OTM-52-9 to calculate the apparent duty cycle of the enclosed
combustion device. Where NSp is the total number of data points in the entire test
period and NDc is the number of data points that meets the following definition:
Number of data points that meet either: 1) the measured C02 (corrected to
remove background, bias and drift) exceeds 2x background concentration or 2)
HCC (corrected to remove background, bias and drift) exceeds 2x the
background concentration. For HCC sensor with background concentration
measured as zero, the concentration threshold to determine operational status
is 5x the sensor's minimum resolution.
DC =—*100 Eq. OTM-52-9
NSp
13.0 Method Performance
13.1 Calculation of Combustion Efficiency from Intermittent Operating Sources
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
For ECDs with intermittent operation the calculation of combustion efficiency can be
done in one of two ways 1) calculate combustion efficiency using data only from
periods of operation or 2) calculate combustion efficiency using the entire 60-minute
test period. Because of how combustion efficiency is calculated both of these
approaches generate substantially close results, however, slight differences can occur.
The differences between the two calculation approaches are driven by the HCC
analyzer minimum resolution and how ECD operation is defined using outlet only
concentrations. Using the Duty Cycle Assessment outlined in Section 8.6 and the Duty
Cycle Requirements in Table OTM-52-4 ensure that the differences between
combustion efficiency calculation approaches are less than 1% in the worst-case
scenario.
13.2 Method 25A Response Factor Correction
The generic Method 25A response factor correction applied in Section 12.8 was
generated based on flame ionization detector responses and waste gas compositions
measured during the development of this method. Appendix A to this method
describes the waste gas composition used to generate this generic Method 25A
response factor as well as an approach to determine analyzer specific response factors
based on this assumed waste gas composition. By determining a Method 25A
analyzer specific response factor as outlined in Appendix A and using that analyzer
specific response factor will increase the accuracy of test average combustion
efficiency.
13.3 Method 25B Response Factor Correction
The generic Method 25B response factor correction applied in Section 12.9 was
generated based on comparison of Method 25B, Method 25A and Method 320
measurements during the development of this method. Appendix A to this method
describes the typical waste gas composition and an approach to determine analyzer
specific response factors based on this assumed waste gas composition. By
determining a Method 25B analyzer specific response factor as outlined in Appendix A
and using that analyzer specific response factor will increase the accuracy of test
average combustion efficiency.
13.4 Method 320 Method Performance
Tests utilizing Method 320 with an FTIR analyzer for analyte quantification must follow
the Method Performance requirements within Method 320 Section 12.
14.0 Pollution Prevention [Reserved]
15.0 Waste Management [Reserved]
23
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
16.0 Alternative Procedures [Reserved]
17.0 References
1. "EPA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards"
September 1997 as amended May 2012, EPA-600/R-12/531.
2. Method 3A - Determination of Oxygen and Carbon Dioxide Concentrations in Emissions from
Stationary Sources (Instrumental Analyzer Procedure)
3. Method 7E - Determination of Nitrogen Oxides Emissions from Stationary Sources
(Instrumental Analyzer Procedure)
4. Method 10 - Determination of Carbon Monoxide Emissions from Stationary Source
5. Method 25A—Determination of Total Gaseous Organic Concentration Using a Flame Ionization
Analyzer
6. Method 25B—Determination of Total Gaseous Organic Concentration Using a Nondispersive
Infrared Analyzer
7. Method 320 — Measurement of Vapor Phase Organic and Inorganic Emissions by Extractive
Fourier Transform Infrared (FTIR) Spectroscopy
18.0 Tables, Diagrams Flowcharts, and Validation Data
Table OTM-52-1
Analyte
Calibration
Gas Cone,
(ppmv)
Analyzer
Response
ppmv CH4
Analyzer
Response
ppmv C02
Analyzer
Response
ppmv CO
Percent
of Span
Low/Zero
CH4
Mid
Span
Low/Zero
o
u
Mid
Span
Low/Zero
CO
Mid
Span
24
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Table OTM-52-2
Time (minutes)
ch4
CO
C02
Cone.
Cone.
Cone.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
CH4stability (15 min)=
CH4 stability (30 min)=
CO stability (15 min)=
CO stability (30 min)=
C02 stability (15 min)=
C02 stability (30 min)=
25
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Table OTM-52-3
Pre-test
Post-test
Calibration Gas
Level
Certified Gas
Concentration
System
Response
System Bias
(%of span)
System
Response
System Bias
(%of span)
Drift
(%of span)
Low Level Gas
Upscale level
gas
Table OTM-52-4
Duty Cycle Requirements
HCC Sensor Minimum
Resolution
Required Duty Cycle (%)
100 ppm
>80%
10 ppm
>33%
<1 ppm
>5%
26
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
OTM-52 Appendix A: Procedure for Determination of Analyzer Specific Response Factor
1.0 Scope and Applicability
This procedure is used to determine an analyzer specific response factor for use with OTM-52.
The analyzer specific response factor converts the analyzer response to that of hydrocarbon
measurements on a single carbon basis. This procedure is used with Method 25A and Method
25B analyzers.
2.0 Summary of Procedure
A Method 25A or Method 25B analyzer samples a gas mixture, that is typical of oil and gas
production facility waste stream, to determine the unique analyzer specific response factor.
You must meet the design specifications, analyzer performance requirements, and test
procedures of this procedure to ensure reliable determination of analyzer specific response
factors. The concentration measurement device may be referred to as a "gas analyzer", a
"sensor", or an "instrument", with these terms used interchangeably in this method.
3.0 Definitions
3.1 Calibration Gas means a gas mixture containing an analyte or analytes at a known
concentration and produced and certified in accordance with "EPA Traceability Protocol
for Assay and Certification of Gaseous Calibration Standards," September 1997, as
amended May, 2012, EPA-600/R-12/5311 or more recent updates. The system verification
tests in OTM 52 require the use of calibration gas prepared according to this protocol. In
the absence of reference materials to which a protocol gas may be made traceable,
implementors of this method may follow ALT-105 as appropriate, to generate the
calibration gases needed for use with this method.
3.1.1 Methane Calibration Span (See Section 7.1.1)
3.1.2 Response Factor Gas Mixture (See Section 7.1.2)
4.0 Interferences [Reserved]
5.0 Safety
This procedure may require you to work with hazardous materials and equipment in
hazardous conditions. This test procedure may not address all the safety problems associated
with its use. It is the responsibility of the user of this procedure to establish appropriate safety
and health practices and determine the applicability of regulatory limitations prior to
performing this procedure. We encourage you to establish safety measures before using the
27
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
procedure. Among other precautions, you should become familiar with the safety
recommendations in the gas analyzer user's manual. Occupational Safety and Health
Administration (OSHA) regulations concerning pressurized gas cylinders and noxious gases
may apply. All calibration gases must be handled with utmost care and with adequate
ventilation.
6.0 Equipment
The performance criteria in this method will be met or exceeded if you are properly using
equipment designed for this application.
6.1 Measurement System Components
6.1.1 Calibration Gas Manifold. Prepare an apparatus to allow the introduction of
calibration gases directly to the gas analyzer(s). The apparatus should be able
to vent excess calibration gas.
6.1.2 Organic Concentration Analyzer (Method 25A)5. You may use a flame
ionization analyzer (FIA) capable of meeting or exceeding the specifications of
this method and the analyzer performance requirements in Appendix A, Table
9-1.
6.1.3 Organic Concentration Analyzer (Method 25B)6. You may use a nondispersive
infrared (NDIR) analyzer designed to measure alkane organics and capable of
meeting or exceeding the specifications in this method and the analyzer
performance requirements in Appendix A, Table 9-1.
6.1.4 Data Recorder. A computerized data acquisition system, digital recorder, or
data logger for recording measurement data may be used. The minimum data
recording requirement is one measurement value every 10 seconds.
7.0 Reagents and Standards
7.1 Calibration Gases
7.1.1 Methane Calibration Span.
The calibration gas for the gas analyzer shall be methane (CH4) in N2 or CH4 in
synthetic air. The calibration gas must be certified (or recertified) within an
uncertainty of 2.0 percent in accordance with "EPA Traceability Protocol for
Assay and Certification of Gaseous Calibration Standards" September 1997, as
amended May 2012, EPA-600/R-12/5311. In the absence of reference
materials to which a protocol gas may be made traceable, implementors of
this method may follow ALT-105 as appropriate, to generate the calibration
gases needed for use with this method.
28
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
For this procedure a calibration gas mole concentration of about 2,000 ppm
methane is recommended. However, the methane calibration gas used to
meet Section 7.1.1 of OTM-52 is also acceptable.
7.1.2 Response Factor Gas Mixture.
7.1.2.1 The gas mixture used to determine analyzer specific response factor is
dependent on the type of waste gas emission sources being combusted by
enclosed combustion device (ECD) using OTM-52. You may use one of the two
most common mixtures representing emission sources at oil and gas
production facilities include tank vapors and dehydration unit vapors.
7.1.2.2 For analyzers used to test ECDs combusting oil tank vapor streams the
analyte and concentrations listed under "Tank Vapors - Molar Cone, (ppm)" in
Table 7-1 shall be used as an approximate gas mixture for the determination
of the analyzer specific response factor. This composition shall also be used
for analyzers testing ECDs combusting comingled oil tank and dehydration
unit vapor streams.
7.1.2.3 For analyzers that will be used to test ECDs combusting dehydration
unit vapor streams the analyte and concentrations listed under "Dehydration
Unit Vapors - Molar Cone, (ppm)" in Table 7-1 shall be used as an approximate
gas mixture for the determination of the analyzer specific response factor.
Table 7-1 Example Total Single Carbon Concertation Mixture
Tank Vapors
Dehydration Unit Vapors
Analyte
Molar Cone.
Single Carbon
Molar Cone.
Single Carbon
(ppm)
Cone, (ppm)
(ppm)
Cone, (ppm)
Methane
1,250
1,250
1,600
1,600
Ethane
250
500
150
300
Propane
200
600
100
300
Butane
150
600
50
200
Pentane
50
250
30
150
Hexane
50
300
30
180
Heptane
5
35
2.5
18
Total =
-
3,535
-
2,748
Note: Table 7-1 above is an example of how to determine "total single carbon
concentration".
7.1.2.4 For each specific response factor determination an exact "total single
carbon concentration" must be determined using the exact concentrations of
the gas mixture provided by the gas provider. See Section 12.3 for the
calculation of "total single carbon concentration".
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
7.1.3 Zero Gas. High purity nitrogen with less than 0.1 part per million by volume
(ppmv) of organic material (propane or carbon equivalent) or less than 0.1
percent of the span value, whichever is greater.
8.0 Test Procedure
8.1 Initial Measurement System Preparation
8.1.1 Assemble, prepare, and precondition the measurement system according to
your standard operating procedure.
8.1.2 Conduct an initial calibration of the analyzer per the manufacturer(s) directed
calibration procedures using the methane calibration gas identified in section 7.1.1.
8.1.3 Adjust the system to achieve the correct sampling rate or dilution ratio (as
applicable).
8.2 Leak Check.
8.2.1 After you have assembled, prepared, and calibrated your measurement system
and analyzer, you must conduct a leak check by injecting Zero Gas oxygen free gas
through the measurement system.
8.2.2 You must record the result of the check and verify that the 02 reading meets the
leak check performance criteria in Section 9.0, Table 9-1.
8.3 Initial Calibration Bias Check
8.3.1 Operate the measurement system at the normal sampling rate during all
calibration bias checks. Make only the adjustments necessary to achieve proper
calibration gas flow rates at the analyzer.
8.3.2 Introduce the methane calibration gas to the measurement system. Continue to
observe the gas concentration reading until it has reached a final, stable value. Record
this value.
8.3.3 Introduce the Zero Gas to the measurement system. Continue to observe the
Zero Gas reading until it has reached a final, stable value and record the result.
Operate the measurement system at the normal sampling rate during all calibration
bias checks. Make only the adjustments necessary to achieve proper calibration gas
flow rates at the analyzer.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
8.3.4 Systems must meet the calibration bias check performance criteria in Section
9.0, Table 9-1.
8.4 Analyzer Response Factor Testing
8.4.1 Introduce the appropriate gas mixture from Section 7.1.2 to the measurement
system.
8.4.2 Continue to observe the gas concentration reading until it has reached a final,
stable value for at least 2 minutes.
8.4.3 Record this value.
8.5 Post System Bias Check
8.5.1 Introduce the methane calibration gas to the measurement system.
8.5.2 Continue to observe the gas concentration reading until it has reached a final,
stable value.
8.5.3 Record this value.
8.5.4 Introduce the Zero Gas to the measurement system. Continue to observe the
Zero Gas reading until it has reached a final, stable value and record the result.
8.5.5 Operate the measurement system at the normal sampling rate during all system
bias checks. Make only the adjustments necessary to achieve proper calibration gas
flow rates at the analyzer.
9.0 Quality Assurance and Quality Control
Table 9-1 summarizes the QA/QC performance criteria.* The Status column indicates if the
criteria is either Suggested (S), Mandatory (M), or is an Alternative (A).
Table 9-1. Quality Assurance/Quality Control Criteria
Status
Process or
Element
QA/QC Specification
Acceptance Criteria
Checking
Frequency
M
Analyzer design
Analyzer sensor
minimum resolution
Hydrocarbon
Concentration (Method
25A or 25B) - 0.01 %;
Manufacturer
design.
M
Calibration gases
Traceability protocol
Valid certificate required
uncertainty <2.0% of tag
value
Each test
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
M
System
Performance
Leak check
02 reading is less than
or equal to 0.2 percent
Each test
M
System
Performance
Calibration bias check
Within ±5.0% of the
analyzer calibration
span for span and zero
calibration gases
Before and
after each
test
S
Data Recorder
Design
Data resolution
<0.5% of full-scale range
Manufacturer
design
M
Data Recording
Frequency
<10 second average
During test
10.0 Calibration and Standardization
10.1 The initial system bias check described in section 8.3 are required and must meet the
specifications in section 9 before you start analyzer response factor testing.
10.1.1 Make all necessary adjustments to calibrate the gas analyzer and data
recorder.
10.1.2 After the test commences, the system bias check described in section 8.5 is
required after each test run.
10.2 You must maintain a copy of the manufacturer's certification of the calibration gases
used in the analyzer response factor testing.
10.2.1 This certification must include the documentation requirements in the EPA
Traceability Protocol For Assay and Certification of Gaseous Calibration
Standards, September 1997, as amended May, 20121.
10.2.2 When Method 205 is used to produce diluted calibration gases, you must
document that the specifications for the gas dilution system are met for the
test. You must also maintain the date of the most recent dilution system
calibration against flow standards and the name of the person or
manufacturer who carried out the calibration.
11.0 Analytical Procedures
11.1 Because sample collection and analysis are performed together (see Section 8),
additional discussion of the analytical procedure is not necessary.
12.0 Calculations and Data Analysis
You must follow the procedures for calculations and data analysis listed in this section.
12.1 Nomenclature.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
The terms used in the equations are defined as follows:
CAvg = Average unadjusted gas concentration indicated by data recorder during the
analyzer response factor testing (Section 8.4), ppmv.
CGas = Average gas concentration adjusted for bias, ppmv.
CM = Average of initial and final system calibration bias (or 2-point system calibration
error) check responses for the Methane Calibration Gas, ppmv.
Cma = Actual concentration of the Methane Calibration Gas, ppmv.
C0 = Average of the initial and final system calibration bias (or 2-point system
calibration error) check responses from the Zero Gas, ppmv.
SCCjanks = Total single carbon concentration using the tank vapor composition profile.
SCCoehy = Total single carbon concentration using the dehydration unit vapor
composition profile.
12.2 Effluent Gas Concentration
Adjust the value of CAvg (ppmv) for bias using Equation OTM-52-App.A-l
Ccas = (Cavg ~ C0) Eq. OTM-52-App.A-l
12.3 Calculation of Total Single Carbon Concentration
12.3.1 Multiply the molar concentration of each analyte by its carbon number to get
each analyte's single carbon concentration (i.e. multiply methane concentration by 1,
multiply ethane concentration by 2, multiply propane concentration by 3, etc). An
example of analyte specific single carbon concentrations can be seen in Table 7-1.
12.3.2 Sum the analyte specific single carbon concentrations to get a "total single
carbon concentration" or SCC. If the Response Factor Gas Mixture composition is
based on the tank vapor concentration profile from Table 7-1 the total single carbon
concentration is defined as SCCTanks and if the Response Factor Gas Mixture
composition is based on the dehydration unit vapor concentration profile from Table
7-1 the total single carbon concentration is defined as SCCDehy.
12.3.3 Use the calculated SCCTanks value in equation OTM-52-App.A-2 and SCCdehy value
in equation OTM-52-App.A-3.
12.4 Response Factor Determination
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Determine the analyzer specific response factor using the following equations
below. For tests using the tank vapor gas mixture use Equation OTM-52-
App.A-2 and the "total single carbon concentration" calculation methodology
in section 12.3 for the exact concentrations listed on the gas mixture cylinder
used for testing (SCCTanks). For tests using dehydration unit vapor gas mixture
use Equation OTM-52-App.A-3 and the "total single carbon concentration"
calculation methodology in section 12.3 for the exact concentrations listed on
the gas mixture cylinder used for testing (SCCDehy).
When testing using OTM-52 use the analyzer specific response factor
calculated above in lieu of the generic response factor values listed in OTM-
52, Section 12.8 (RF = 1.28) for Method 25A analyzers and OTM-52, Section
12.9 (RF = 0.44) for Method 25B analyzers.
R^TOC-Tanks ~
Eq. OTM-52-App.A-2
Eq. OTM-52-App.A-3
13.0 References
1. "EPA Traceability Protocol for Assay and Certification of Gaseous Calibration Standards"
September 1997 as amended May 2012, EPA-600/R-12/531.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
OTM-52 Appendix B: Procedure for Analysis of Method 320 Measurements
1.0 Purpose
The purpose of this procedure is to determine carbon dioxide (C02), carbon monoxide (CO),
and Hydrocarbon Concentrations (HCC) on a single carbon basis using Method 3201
measurements. This procedure is meant for exclusive use with OTM-52 and should not be
used for any other method.
2.0 Summary of Procedure
This procedure provides three OTM-52 specific requirements when a Method 320 is used to
determine C02, CO and HCC. First, this procedure outlines the analytes to be included in the
spectra analysis. Second, this procedure provides the step by step process to convert
individual hydrocarbon analytes into HCC on a single carbon basis. And finally, this procedure
outlines the spectral analysis validation process required under OTM-52 to ensure accurate
quantification.
3.0 Definitions of Terms
3.1 Analyte. An Analyte is a specific chemical species that is analyzed using an FTIR analytical
software and Reference Spectra to determine its concentration in a gas sample. The most
accurate analyte concentrations are achieved when Reference Spectra for all Interferants are
used in the quantitative analysis.
3.2 Analyte Concentration Calibration Range. Analyte Concentration Calibration Range is the
range of concentrations where the accuracy of the analyte Reference Spectra is accurate to
withing 2%.
4.2 Analysis Recipe. An Analysis Recipe is a data file used to automate the analysis of test run
spectra. The recipe includes a list of analytes to be evaluated and their associated Reference
Spectra as well as other key information required for the automated spectral analysis.
4.3 Interferant. A compound in the sample matrix whose infrared spectrum overlaps with part
of the analyte spectrum. The most accurate analyte measurements are achieved when
reference spectra of interferants are used in the quantitative analysis with the analyte spectra.
4.4 Reference Spectra. A Reference Spectra provides the unique infrared absorption spectrum
for a particular analyte, interferant, surrogate, calibration transfer standards (CTS), or tracer at
a specific temperature and pressure.
4.0 Analysis System Components
4.1 FTIR Analytical Software. A computer will be needed with compatible software allowing
for automated collection, analysis and validation of spectra.
4.2 Analysis Recipe. An analysis recipe as described in section 5.1 below will be needed to
automate the analysis of test run spectra. The recipe shall include all analytes listed in Section
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
5.1.1 and their associated Reference Spectra as well as other key test run specific information
required for the automated spectral analysis of test data.
4.3 Reference Spectra. A reference spectra provides the unique infrared absorption spectrum
for a particular analyte listed in Section 5.1.1, interferant, surrogate, CTS, and tracer at the
specific temperature and pressure used during the test run data collection.
5.0 Method 320 Spectra Analysis Specifications and Procedures
5.1 Analysis Recipe Specifications
5.1.1 Analysis Recipe - Analytes
Create an analysis recipe that includes (at a minimum) the following analytes:
o Water Vapor (H20)
o Carbon Dioxide (C02)
o Carbon Monoxide (CO)
o Methane (CH4)
o Ethane (C2H6)
o Propane (C3H8)
o Butane (C4Hi0)
o Octane (CsHis)
o Ethylene (C2H4)
o Acetylene (C2H2)
o Propylene (C3H6)
o Formaldehyde (CH20)
o Acetaldehyde (CH3CHO)
o Nitrogen Monoxide (NO)
o Nitrogen Dioxide (N02)
o Anhydrous Ammonia (NH3)
o Tracer Chemical Species
5.1.2 Analysis Recipe - Analyte Reference Spectra Considerations
The analyte reference spectra shall be chosen to match the analyzer operating
temperature and pressure during the time of sampling. Additionally, the
reference spectra shall be selected so that the assumed analyte concentration
falls within Analyte Concentration Calibration Range.
5.2 Automated Test Period Sectra Analysis
Following the creation of the Analysis Recipe described above, all test spectra period
spectra (including ambient background measurements and all QA/QC tests) shall be
analyzed using the FTIR Analytical Software. If during spectral processing it is
identified that an analyte(s) concentration(s) are outside the Analyte Concentration
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Calibration Range the spectra shall be reprocessed using an updated Analysis Recipe
with appropriate analyte Reference Spectra.
5.3 Spectral Analysis Manual Validation
A manual validation of the automated spectral analysis completed in Appendix B
Section 5.2 must be completed to ensure accurate analyte quantification and that
there are minimal unknown interferences. A manual validation must be completed for
at least 3 different spectra from each test run.
A manual validation is completed on a spectra via the FTIR Analysis Software and the
general steps are outlined below:
5.3.1 Analyte Analysis Order
The user shall analyze the analytes in the following order.
5.3.1.1 Water Vapor
Water vapor shall be the first analyte to be analyzed due to its large
infrared absorption and significant interferences it causes to other
trace constituents.
5.3.1.2 Carbon Dioxide
Carbon Dioxide shall be the second analyte to analyzed due to its
large infrared absorption and significant interferences it causes to
other trace constituents.
5.3.1.3 Carbon Monoxide
Carbon Monoxide shall be the third analyte to analyzed due to its
large infrared absorption and significant interferences it causes to
other trace constituents.
5.3.1.4 Methane
Methane shall be the third analyte to analyzed due to its large
infrared absorption and significant interferences it causes to other
trace constituents.
5.3.1.5 All Other Analytes
For all additional analytes they should be analyzed in the descending
order based on their concentrations derived during the automated
spectral analysis conducted in OTM-52 Appendix B Section 5.2.
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
5.3.2 Analyte Concentration First-Guess and Optimization
The user shall use the concentration derived during the automated spectral
analysis conducted in OTM-52 Appendix B Section 5.2 as the first guess for the
target Analyte. The concentration of the Analyte shall be varied to minimize
the goodness-of-fit (or similar statistical regression analysis).
Both the initial ('first-guess') and manually optimized concentrations as well
as the goodness-of- fit (or similar statistical regression analysis) of all Analytes
shall be documented and included in a table(s) of the final test report.
5.3.3 Analyte Validation Threshold
For any Analyte with either an initial ('first-guess') or manually optimized
concentration of >10 ppm shall calculate a percent deviation.
For any Analytes subject to the validation threshold and have a percent
deviation calculated shall have the percent deviation included in the final test
report.
5.3.4 Unknown interferences
If substantial absorption residuals exist after all Analytes have been manually
validated the user shall attempt to identify the source of the interference. If
the source of the interference is identified as a hydrocarbon, it shall be added
to the list of Analytes and the data shall be reprocessed.
If a substantial absorption interference is identified following manual
validation this shall be noted in the final test report.
5.4 Carbon Dioxide Quantification Procedure
For each test run, average the carbon dioxide concentrations from the spectral
analysis. The test-run averaged carbon dioxide concentration shall be bias corrected,
and background adjusted to determine CCo2 as described in OTM-52 Section 12.7.
5.5 Carbon Monoxide Single Carbon Quantification Procedure
For each test run, average the carbon monoxide concentrations from the spectral
analysis. The test-run averaged carbon monoxide concentration shall be bias
corrected, and background adjusted to determine CCo as described in OTM-52 Section
12.7.
5.6 Hydrocarbon Concentration Single Carbon Quantification Procedure
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
The following procedure uses all of the hydrocarbon Analytes' concentrations from
the analyzed test period spectra data to determine the HCC on a single carbon basis.
The following procedures must be followed for any OTM-52 HCC determination.
5.6.1 Nomenclature
The terms used in the equations are defined as follows:
Cmeas(anaiyte(i)) = Analyte (i)'s concentration in molecule basis, ppmv
Ccarbon(anaiyte(i)) = Analyte (i)'s concentration in single carbon basis, ppmv,c
K = Carbon equivalent correction factor,
n = Number of hydrocarbon Analytes
HCCcarbon = Hydrocarbon Concentration on single carbon basis, ppmv,c
5.6.2 Analyte Single Carbon Basis Conversion
For each test run, average the concentrations of each analyte. Then use
Equation OTM-52-AppB-l to calculate the test-average, analyte specific
concentration on the single carbon basis using the appropriate carbon
equivalent correction factor (K) listed in Table 5-1 for each hydrocarbon
analyte.
Ccarbon(Analytei) ^Meas{Analyte{) % K Eq. OTM-52-AppB-l
Table 5-1 Minimum Hydrocarbon Analyte Carbon Count List
Hydrocarbon
Carbon
Analyte
Count (K)
Methane
1
Formaldehyde
1
Ethane
2
Ethylene
2
Acetylene
2
Acetaldehyde
2
Propane
3
Propylene
3
Butane
4
Octane
8
5.1.3.2 Hydrocarbon Concentration on Single Carbon Basis
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OTM-52: Method for Determination of Combustion Efficiency from Enclosed Combustion Devices Located at Oil and Gas Facilities
Use Equation OTM-52-AppB-2 to calculate the test-average HCC
concentration on the single carbon basis.
HCCcarbon 2i = i CCarbon(Analytei) Eq. OTM-52-AppB-2
For each test run, HCCCarbon shall be bias corrected, and background adjusted
to determine CHcc as described in OTM-52 Section 12.6.
6.0 References
1. Method 320 — Measurement of Vapor Phase Organic and Inorganic Emissions by Extractive
Fourier Transform Infrared (FTIR) Spectroscopy
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