ASTM D6522-00

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Designation:D6522–00
Standard Test Method for
Determination of Nitrogen Oxides, Carbon Monoxide, and
Oxygen Concentrations in Emissions from Natural Gas-
Fired Reciprocating Engines, Combustion Turbines, Boilers,
and Process Heaters Using Portable Analyzers
This standard is issued under the fixed designation D6522; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope Concentrations in Emissions from Stationary Sources
(Instrumental Analyzer Procedure)
1.1 This test method covers the determination of nitrogen
Method 7E - Determination of Nitrogen Oxides Emissions
oxides (NO and NO ), carbon monoxide (CO), and oxygen
from Stationary Sources (Instrumental Analyzer Proce-
(O ) concentrations in controlled and uncontrolled emissions
dure)
from natural gas-fired reciprocating engines, combustion tur-
Method10 -DeterminationofCarbonMonoxideEmissions
bines, boilers, and process heaters. Due to the inherent cross
from Stationary Source
sensitivities of the electrochemical cells, this test method
Method 20 - Determination of Nitrogen Oxides, Sulfur
should not be applied to other pollutants or emission sources
Dioxide, and Diluent Emissions from Stationary Gas
without a complete investigation of possible analytical inter-
Turbines
ferences and a comparative evaluation with EPAtest methods.
2.3 EPA Methods from 40 CFR Part 63, Appendix A
1.1.1 Theproceduresandspecificationsofthismethodwere
Method 301 - Field Validation of Pollutant Measurement
developed during laboratory and field tests funded by the Gas
Methods from Various Waste Media
Research Institute (GRI). Comparative emission tests were
2.4 EPA Methods from 40 CFR Part 75, Appendix H
conducted only on natural gas-fired combustion sources.
Revised Traceability Protocol No. 1: Protocol G1 and G2
1.2 The values stated in SI units are to be regarded as the
Procedures
standard. The values given in parentheses are for information
only.
3. Terminology
1.3 This standard does not purport to address all of the
3.1 For terminology relevant to this test method, seeTermi-
safety concerns, if any, associated with its use. It is the
nology D1356.
responsibility of the user of this standard to establish appro-
3.2 Definitions of Terms Specific to This Standard:
priate safety and health practices and to determine the
3.2.1 measurement system, n—total equipment required for
applicability of regulatory limitations prior to use.
the determination of gas concentration. The measurement
2. Referenced Documents system consists of the following major subsystems:
3.2.1.1 datarecorder,n—astripchartrecorder,computer,or
2.1 ASTM Standards:
digital recorder for recording measurement data.
D1356 Terminology Relating to Sampling andAnalysis of
3.2.1.2 electrochemical cell, n—that portion of the system
Atmospheres
4 that senses the gas to be measured and generates an output
2.2 EPA Methods from 40 CFR Part 60, Appendix A
proportional to its concentration, or any cell that uses
Method3A -DeterminationofOxygenandCarbonDioxide
diffusion-limited oxidation and reduction reactions to produce
an electrical potential between a sensing electrode and a
counter electrode.
This test method is under the jurisdiction of ASTM Committee D22 on Air
3.2.1.3 external interference gas scrubber, n—tube filled
Quality and is the direct responsibility of Subcommittee D22.03 on Ambient
with scrubbing agent used to remove interfering compounds
Atmospheres and Source Emissions.
upstream of some electrochemical cells.
Current edition approved February 10, 2000. Published April 2000.
Gas Research Institute Topical Report, “Development of an Electrochemical
3.2.1.4 sample interface, n—that portion of a system used
Cell Emission Analyzer Test Method,” GRI-96/0008, July 1997.
for one or more of the following: sample acquisition, sample
Annual Book of ASTM Standards, Vol 11.03.
transport, sample conditioning, or protection of the electro-
Available from Superintendent of Documents, U. G. Government Printing
Office, Washington, DC 20402. chemicalcellsfromparticulatematterandcondensedmoisture.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
D6522–00
3.2.2 interference check, n—method of quantifying analyti- measurements. The interference effects for the CO and NO
cal interferences from components in the stack gas other than emission measurements are quantified in 9.2 and shall not
the analyte. exceed 5% of the measurement.
3.2.3 initial NO cell temperature, n—temperatureoftheNO
7. Apparatus
cell that is recorded during the most recent pretest calibration
7.1 The minimum detectable limit depends on the nominal
error check.
range of the electrochemical cell, calibration drift, and signal-
3.2.3.1 Discussion—Since the NO cell can experience sig-
to-noise ratio of the measurement system. For a well designed
nificantzerodriftwithtemperaturechangesinsomesituations,
system, the minimum detectable limit should be less than 2%
the temperature must be monitored if the analyzer does not
of the nominal range.
display negative concentration results.
7.2 Any measurement system that meets the performance
3.2.4 linearity check, n—method of demonstrating the abil-
and design specifications in Sections 9 and 10.4.11 of this test
ityofagasanalyzertorespondconsistentlyoverarangeofgas
method may be used. The sampling system shall maintain the
concentrations.
gas sample at a temperature above the dew point up to the
3.2.5 nominal range, n—range of concentrations over
moisture removal system. The sample conditioning system
whicheachcellisoperated(25%to125%ofspangasvalue).
shall be designed so that there are no entrained water droplets
3.2.5.1 Discussion—Several nominal ranges may be used
in the gas sample when it contacts the electrochemical cells.A
for any given cell as long as the linearity and stability check
schematic of an acceptable measurement system is shown in
results remain within specification.
Fig. 1. The essential components of the measurement system
3.2.6 response time, n—amount of time required for the
are described below:
measurement system to display 95% of a step change in gas
7.3 Sample Probe,glass,stainlesssteel,orothernonreactive
concentration on the data recorder.
material,ofsufficientlengthtotraversethesamplepoints,and,
3.2.7 span gas, n—known concentration of a gas in an
if necessary, heated to prevent condensation.
appropriate diluent gas.
7.4 Heated Sample Line, heated (sufficient to prevent con-
3.2.8 span calibration error, n—difference between the gas
densation), nonreactive tubing, to transport the sample gas to
concentration exhibited by the gas analyzer and the known
the moisture removal system.
concentration of the span gas.
7.5 Sample Transport Lines, nonreactive tubing to transport
3.2.9 stability check, n—method of demonstrating that an
the sample from the moisture removal system to the sample
electrochemical cell operated over a given nominal range
pump, sample flow rate control, and electrochemical cells.
provides a stable response and is not significantly affected by
7.6 Calibration Assembly,atee-fittingtoattachtotheprobe
prolonged exposure to the analyte.
tipforintroducingcalibrationgasesatambientpressureduring
3.2.10 stability time, n—elapsed time from the start of the
the calibration error checks. The vented end of the tee should
gasinjectiontothestartofthe30-minstabilitycheckperiod,as
have a flow indicator to ensure sufficient calibration gas flow.
determined during the stability check.
Anyothermethodthatintroducescalibrationgasesattheprobe
3.2.11 zero calibration error, n—gas concentration exhib-
at atmospheric pressure may be used.
ited by the gas analyzer in response to zero-level calibration
7.7 MoistureRemovalSystem,achilledcondenserorsimilar
gas.
device (for example, permeation dryer), to remove condensate
4. Summary of Test Method
4.1 Agassampleiscontinuouslyextractedfromastackand
conveyedtoaportableanalyzerfordeterminationofNO,NO ,
CO, and O gas concentrations using electrochemical cells.
Analyzer design specifications, performance specifications,
and test procedures are provided to ensure reliable data.
Additionstoormodificationsofvendor-suppliedanalyzers(for
example,heatedsampleline,flowmeters,andsoforth)maybe
required to meet the design specifications of this test method.
5. Significance and Use
5.1 Theresultsofthistestmethodmaybeusedtodetermine
nitrogen oxides and carbon monoxide emissions from natural
gas combustion.
5.2 Thistestmethodmayalsobeusedtomonitoremissions
to optimize process operation for nitrogen oxides and carbon
monoxide control.
6. Interferences
6.1 NO and NO can interfere with CO concentration
measurements, and NO can interfere with NO concentration FIG. 1 Calibration System Schematic
D6522–00
continuously from the sample gas while maintaining minimal 8.2.2 Alternative certification techniques may be used, if
contact between the condensate and the sample gas. approved in writing by the applicable regulatory agency.
7.8 Particulate Filters—Filters at the probe or the inlet or 8.3 Span Gases—Use these gases for calibration error,
outlet of the moisture removal system and inlet of the analyzer linearity, and interference checks of each nominal range of
may be used to prevent accumulation of particulate material in each cell. Select concentrations as follows:
the measurement system and extend the useful life of the 8.3.1 CO and NO Span Gases—Choose a span gas concen-
components.All filters shall be fabricated of materials that are trationsuchthattheaveragestackgasreadingforeachtestrun
nonreactive to the gas being sampled. is greater than 25% of the span gas concentration. Alterna-
7.9 Sample Pump, a leak-free pump, to pull the sample gas tively,choosethespangassuchthatitisnotgreaterthantwice
through the system at a flow rate sufficient to minimize the the concentration equivalent to the emission standard. If
response time of the measurement system. The pump must be concentration results exceed 125% of the span gas at any time
constructed of any material that is nonreactive to the gas being during the sampling run, then the test run for that channel is
sampled. invalid.
7.10 Sample Flow Rate Control, a sample flow rate control 8.3.2 NO Span Gas—Choose a span gas concentration
valve and rotameter, or equivalent, to maintain a constant such that the average stack gas reading for each test run is
sampling rate within 10% during sampling and calibration greater than 25% of the span gas concentration.Alternatively,
error checks. The components shall be fabricated of materials choose the span gas concentration such that it is not greater
that are nonreactive to the gas being sampled. than the ppm concentration value of the NO span gas. The
7.11 Gas Analyzer, a device containing electrochemical tester should be aware that NO cells are generally designed to
cells to determine the NO, NO , CO, and O concentrations in measuremuchlowerconcentrationsthanNOcellsandthespan
2 2
the sample gas stream and, if necessary, to correct for interfer- gas should be chosen accordingly. If concentration results
ence effects. The analyzer shall meet the applicable perfor- exceed 125% of the span gas at any time during the sampling
mance specifications of Section 9. A means of controlling the run then the test run for that channel is invalid.
analyzer flow rate and a device for determining proper sample 8.3.3 O Span Gas—Choose a span gas concentration such
flow rate (for example, precision rotameter, pressure gage that the difference between the span gas concentration and the
downstreamofallflowcontrols,andsoforth)shallbeprovided average stack gas reading for each run is less than 10% O .
at the analyzer. Where the stack oxygen is high, dry ambient air (20.9% O )
may be used.
NOTE 1—Housing the analyzer in a clean, thermally-stable, vibration-
8.4 Mid-Level Gases—Select mid-level gas concentrations
freeenvironmentwillminimizedriftintheanalyzercalibration,butthisis
that are 40 to 60% of the span gas concentrations.
not a requirement of the test method.
8.5 Zero Gas—Zero gas must have concentrations of less
7.12 Data Recorder, a strip chart recorder, computer, or
than 0.25% of the span gas for each component. Ambient air
digital recorder, for recording measurement data. The data
may be used in a well-ventilated area.
recorder resolution (that is, readability) shall be at least 1 ppm
for CO, NO, and NO ; 0.1% O for O ; and 1° (C or F) for
9. Preparation of Apparatus
2 2 2
temperature.Alternatively,adigitaloranalogmeterhavingthe
9.1 Linearity Check:
same resolution may be used to obtain the analyzer responses
9.1.1 Conduct the linearity check once for each nominal
and the readings may be recorded manually.
rangethatistobeusedoneachelectrochemicalcell(NO,NO ,
7.13 External Interference Gas Scrubber, used by some
CO, and O ) before each field test program.
analyzers to remove interfering compounds upstream of a CO
9.1.1.1 Repeat the linearity check immediately after 5 days
electrochemicalcell.Thescrubbingagentshouldbevisibleand
of analyzer operation, if a field test program lasts longer than
should have a means of determining when the agent is
5 days.
exhausted (that is, color indication).
9.1.1.2 Repeat the linearity check whenever a cell is re-
7.14 NO Cell Temperature Indicator, a thermocouple, ther-
placed.
mistor,orotherdevicemustbeusedtomonitorthetemperature
9.1.2 If the analyzer uses an external interference gas
of the NO electrochemical cell. The temperature may be
scrubber with a color indicator, verify that the scrubbing agent
monitored at the surface or within the cell.
is not depleted, following the analyzer manufacturer’s recom-
mended procedure.
8. Reagents and Materials
9.1.3 Calibrate the analyzer with zero and span gases.
8.1 The analytical range for each gas component is deter- 9.1.4 Inject the zero, mid-level, and span gases that are
mined by the electrochemical cell design. A portion of the appropriate for each nominal range to be used on each cell.
analytical range is selected by choosing a span gas concentra- Gases need not be injected through the entire sample handling
tion near the flue gas concentrations. system.
8.2 Calibration Gases—The calibration gases for the gas 9.1.5 Purge the analyzer, briefly with ambient air between
analyzershallbeCOinnitrogenorCOinnitrogenandO,NO gas injections.
in nitrogen, NO in air or nitrogen, and O in nitrogen. 9.1.6 For each gas injection, verify that the fl
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