Stationary source emissions - Determination of the mass concentration of ammonia in flue gas - Performance characteristics of automated measuring systems

This International Standard specifies the fundamental structure and the most important performance
characteristics of automated measuring systems for ammonia (NH3) to be used on stationary source
emissions, for example, combustion plants where SNCR/SCR NOx control systems (deNOx systems) are
applied. The procedures to determine the performance characteristics are also specified. Furthermore,
it describes methods and equipment to determine NH3 in flue gases including the sampling system and
sample gas conditioning system.
This International Standard describes extractive systems, based on direct and indirect measurement
methods, and in situ systems, based on direct measurement methods, in connection with a range of
analysers that operate using, for example, the following principles:
— ammonia conversion to, or reaction with NO, followed by chemiluminescence (CL) NOx difference
measurement for ammonia (differential NOx);
— ammonia conversion to, or reaction with NO, followed by non-dispersive ultraviolet (NDUV)
spectroscopy NOx difference measurement for ammonia (differential NOx);
— Fourier transform infrared (FTIR) spectroscopy;
— non-dispersive infrared (NDIR) spectroscopy with gas filter correlation (GFC);
— tuneable laser spectroscopy (TLS).
The method allows continuous monitoring with permanently installed measuring systems of NH3
emissions, and is applicable to measurements of NH3 in dry or wet flue gases, for process monitoring,
long term monitoring of the performance of deNOx systems and/or emission monitoring.
Other equivalent instrumental methods can be used, provided they meet the minimum requirements
proposed in this International Standard. The measuring system can be calibrated with certified gases,
in accordance with this International Standard, or comparable methods.
The differential NOx technique using CL has been successfully tested on some power plants where the
NOx concentration and NH3 concentration in flue gas after deNOx systems are up to 50 mg (NO)/m3 and
10 mg (NH3)/m3, respectively. AMS based on FTIR, NDIR with GFC and TLS has been used successfully
in this application for measuring ranges as low as 10 mg (NH3)/m3.

Émission des sources fixes - Détermination de la concentration massique de l'ammoniac dans les gaz de combustion - Caractéristiques de performance des systèmes de mesure automatisés

Emisije nepremičnih virov - Določevanje masne koncentracije amoniaka v odpadnih plinih - Delovne karakteristike avtomatskih merilnih sistemov

Ta mednarodni standard določa temeljno strukturo in najpomembnejše delovne karakteristike avtomatskih merilnih sistemov za amoniak (NH3), ki se uporabljajo na emisijah nepremičnih virov, na primer na kurilnih napravah, kjer se uporabljajo sistemi za nadzor NOx SNCR/SCR (sistemi deNOx). Opredeljeni so tudi postopki za določanje značilnosti delovanja. Poleg tega opisuje metode in opremo za določanje NH3 v odpadnih plinih, vključno s sistemom za vzorčenje in sistemom za pripravo vzorčnega plina.
Ta mednarodni standard opisuje ekstraktivne sisteme, ki temeljijo na neposrednih in posrednih merilnih metodah, ter sisteme in situ, ki temeljijo na neposrednih merilnih metodah, v povezavi z vrsto analizatorjev, ki delujejo na primer z naslednjimi načeli:
– pretvorba amoniaka v NO ali reakcija z NO, čemur sledi merjenje kemoluminiscence (CL) NOx za amoniak (diferencialni NOx);
– pretvorba amoniaka v NO ali reakcija z NO, čemur sledi merjenje nedisperzne ultraviolične (NDUV) spektroskopije NOx za amoniak (diferencialni NOx);
– infrardeča spektroskopija s Fourierjevo transformacijo (FTIR);
– nedisperzna infrardeča (NDIR) spektroskopija s korelacijo plinskega filtra (GFC);
– nastavljiva laserska spektroskopija (TLS).
Metoda omogoča neprekinjeno spremljanje s stalno nameščenimi merilnimi sistemi za emisije NH3 in se uporablja za meritve NH3 v suhih ali mokrih odpadnih plinih, za spremljanje procesa, dolgoročno spremljanje delovanja sistemov za deNOx in/ali spremljanje emisij.
Uporabiti je mogoče tudi druge enakovredne instrumentalne metode, če izpolnjujejo minimalne zahteve, predlagane v tem mednarodnem standardu. Merilni sistem je mogoče umeriti s certificiranimi plini v skladu s tem mednarodnim standardom ali s primerljivimi metodami.
Tehnika diferencialnega NOx z uporabo CL je bila uspešno preskušena v nekaterih obratih, v katerih je koncentracija NOx in NH3 v odpadnih plinih za sistemi deNOx do 50 mg (NO)/m3 in
10 mg (NH3)/m3. AMS na osnovi FTIR, NDIR z GFC in TLS se uspešno uporablja v tej aplikaciji za tako nizka meritvena območja, kot je 10 mg (NH3)/m3.

General Information

Status
Published
Public Enquiry End Date
09-Oct-2018
Publication Date
30-May-2019
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
31-May-2019
Due Date
05-Aug-2019
Completion Date
31-May-2019

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INTERNATIONAL ISO
STANDARD 17179
First edition
2016-07-01
Stationary source emissions —
Determination of the mass
concentration of ammonia in flue
gas — Performance characteristics of
automated measuring systems
Émission des sources fixes — Détermination de la concentration
massique de l’ammoniac dans les gaz de combustion —
Caractéristiques de performance des systèmes de mesure automatisés
Reference number
ISO 17179:2016(E)
ISO 2016
---------------------- Page: 1 ----------------------
ISO 17179:2016(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2016, Published in Switzerland

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form

or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior

written permission. Permission can be requested from either ISO at the address below or ISO’s member body in the country of

the requester.
ISO copyright office
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Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2016 – All rights reserved
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ISO 17179:2016(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and abbreviated terms ........................................................................................................................................................... 5

5 Principle ........................................................................................................................................................................................................................ 6

6 Description of the automated measuring systems ............................................................................................................ 6

6.1 Sampling and sample gas conditioning systems ........................................................................................................ 6

6.2 Analyser equipment ........................................................................................................................................................................... 6

7 Performance characteristics .................................................................................................................................................................... 6

7.1 Performance criteria .......................................................................................................................................................................... 6

7.2 Determination of the performance characteristics ................................................................................................. 7

7.2.1 Performance test .............................................................................................................................................................. 7

7.2.2 Ongoing quality control ............................................................................................................................................. 8

8 Measurement procedure .............................................................................................................................................................................. 8

8.1 General ........................................................................................................................................................................................................... 8

8.2 Choice of the measuring system .............................................................................................................................................. 8

8.3 Sampling ....................................................................................................................................................................................................... 9

8.3.1 Sampling location ............................................................................................................................................................ 9

8.3.2 Sampling point(s) ............................................................................................................................................................ 9

8.4 Data collection ......................................................................................................................................................................................... 9

8.5 Calculation .................................................................................................................................................................................................. 9

9 Quality assurance and quality control procedures .......................................................................................................10

9.1 General ........................................................................................................................................................................................................10

9.2 Frequency of checks ........................................................................................................................................................................10

9.3 Calibration, validation and measurement uncertainty .....................................................................................11

10 Test report ................................................................................................................................................................................................................11

Annex A (informative) Extractive differential NO measurement technique ..........................................................13

Annex B (informative) Extractive direct NH measurement technique ........................................................................17

Annex C (informative) In situ and direct NH measurement with TLS analyser ..................................................20

Annex D (normative) Operational gases .......................................................................................................................................................24

Annex E (normative) Procedures for determination of the performance characteristics

during the general performance test ...........................................................................................................................................26

Annex F (informative) Examples of the results for the assessment of ammonia AMS ...................................34

Annex G (informative) Calculation of uncertainty of measurement of NH .............................................................36

Bibliography .............................................................................................................................................................................................................................40

© ISO 2016 – All rights reserved iii
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ISO 17179:2016(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,

as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the

Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.

The committee responsible for this document is ISO/TC 146, Air quality, Subcommittee SC 1, Stationary

source emissions.
iv © ISO 2016 – All rights reserved
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ISO 17179:2016(E)
Introduction

Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) NO control systems

are used for emission control of NO in flue gas from power generation plants, waste incinerators and

others. The NO reduction technologies require the injection of ammonia (NH ) and/or urea into flue

x 3

gas. The SCR system is designed to be operated at unreacted NH in flue gas (or remained NH in flue

3 3
3 3

gas) as small as possible (typically below 2 mg/m to 4 mg/m NH concentration) with more than

90 % NO reduction efficiency. The standardization of a measurement method of NH is thus strongly

x 3

desired for efficient operation and maintenance of the NO control systems and for minimization of

environmental impacts due to ammonia and NO .
© ISO 2016 – All rights reserved v
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INTERNATIONAL STANDARD ISO 17179:2016(E)
Stationary source emissions — Determination of the mass
concentration of ammonia in flue gas — Performance
characteristics of automated measuring systems
1 Scope

This International Standard specifies the fundamental structure and the most important performance

characteristics of automated measuring systems for ammonia (NH ) to be used on stationary source

emissions, for example, combustion plants where SNCR/SCR NO control systems (deNO systems) are

x x

applied. The procedures to determine the performance characteristics are also specified. Furthermore,

it describes methods and equipment to determine NH in flue gases including the sampling system and

sample gas conditioning system.

This International Standard describes extractive systems, based on direct and indirect measurement

methods, and in situ systems, based on direct measurement methods, in connection with a range of

analysers that operate using, for example, the following principles:

— ammonia conversion to, or reaction with NO, followed by chemiluminescence (CL) NO difference

measurement for ammonia (differential NO );

— ammonia conversion to, or reaction with NO, followed by non-dispersive ultraviolet (NDUV)

spectroscopy NO difference measurement for ammonia (differential NO );
x x
— Fourier transform infrared (FTIR) spectroscopy;
— non-dispersive infrared (NDIR) spectroscopy with gas filter correlation (GFC);
— tuneable laser spectroscopy (TLS).

The method allows continuous monitoring with permanently installed measuring systems of NH

emissions, and is applicable to measurements of NH in dry or wet flue gases, for process monitoring,

long term monitoring of the performance of deNO systems and/or emission monitoring.

Other equivalent instrumental methods can be used, provided they meet the minimum requirements

proposed in this International Standard. The measuring system can be calibrated with certified gases,

in accordance with this International Standard, or comparable methods.

The differential NO technique using CL has been successfully tested on some power plants where the

NO concentration and NH concentration in flue gas after deNO systems are up to 50 mg (NO)/m and

x 3 x

10 mg (NH )/m , respectively. AMS based on FTIR, NDIR with GFC and TLS has been used successfully

in this application for measuring ranges as low as 10 mg (NH )/m .
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 9169, Air quality — Definition and determination of performance characteristics of an automatic

measuring system

ISO 14956, Air quality — Evaluation of the suitability of a measurement procedure by comparison with a

required measurement uncertainty
ISO 20988, Air quality — Guidelines for estimating measurement uncertainty
© ISO 2016 – All rights reserved 1
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ISO 17179:2016(E)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
analyser
analytical part in an extractive or in situ AMS (3.3)
[SOURCE: ISO 12039:2001, 3.3]
3.2
automated measuring system
AMS

measuring system interacting with the flue gas under investigation, returning an output signal

proportional to the physical unit of the measurand (3.11) in unattended operation

Note 1 to entry: In the sense of this International Standard, an AMS is a system that can be attached to a duct or

stack to continuously or intermittently measure the mass concentration of NH passing through the duct.

[SOURCE: ISO 9169:2006, 2.1.2, modified.]
3.3
in situ AMS

non-extractive systems that measure the concentration directly in the duct or stack

Note 1 to entry: In situ systems measure either across the stack or duct or at a point within the duct or stack.

3.4
calibration of an automated measuring system

procedure for establishing the statistical relationship between values of the measurand (3.11) indicated

by the automated measuring system (3.2) and the corresponding values given by an independent method

of measurement implemented simultaneously at the same measuring point
3.5
efficiency of NH /NO
efficiency of a converter which oxidizes NH to NO
3.6
efficiency of NH /N
3 2
efficiency of a converter which reduces NH to N
3 2
3.7
influence quantity

quantity that is not the measurand (3.11) but that affects the result of the measurement

[SOURCE: ISO/IEC Guide 98-3:2008, B.2.10]
3.8
interference
cross-sensitivity

negative or positive effect upon the response of the measuring system, due to a component of the

sample that is not the measurand (3.11)
3.9
interferent
interfering substance

substance present in the air mass under investigation, other than the measurand (3.11), that affects the

response
[SOURCE: ISO 9169:2006, 2.1.12]
2 © ISO 2016 – All rights reserved
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ISO 17179:2016(E)
3.10
lack-of-fit

systematic deviation within the range of application between the measurement results obtained

by applying the calibration function to the observed response of the measuring system, measuring

reference materials (3.16) and the corresponding accepted value of such reference materials

Note 1 to entry: Lack of-fit may be a function of the measurement result.

Note 2 to entry: The expression “lack-of-fit” is often replaced in everyday language for linear relations by

“linearity” or “deviation from linearity”.
[SOURCE: ISO 9169:2006, 2.2.9, modified.]
3.11
measurand
particular quantity subject to measurement
[SOURCE: ISO/IEC Guide 98-3:2008, B.2.9, modified.]
3.12
NO /NO converter efficiency
efficiency with which the converter unit of a NO analyser reduces NO to NO
x 2
3.13
performance characteristic
one of the quantities assigned to equipment in order to define its performance

Note 1 to entry: Performance characteristics can be described by values, tolerances, or ranges.

3.14
period of unattended operation

maximum interval of time for which the performance characteristics (3.13) remain within a predefined

range without external servicing, e.g. refill, adjustment

Note 1 to entry: The period of unattended operation is often called maintenance interval.

[SOURCE: ISO 9169:2006, 2.2.11]
3.15
reference gas

gaseous mixture of stable composition used to calibrate the measuring system and which is traceable

to national or international standards
3.16
reference material

substance or mixture of substances with a known concentration within specified limits, or a device of

known characteristics

Note 1 to entry: Normally used are calibration gases, gas cells, gratings, or filters.

[SOURCE: ISO 14385-1:2014, 3.20]
3.17
reference method

measurement method taken as a reference by convention, which gives the accepted reference value of

the measurand (3.11)
3.18
transport time in the measuring system

time period for transportation of the sampled gas from the inlet of the probe to the inlet of the

measurement instrument
© ISO 2016 – All rights reserved 3
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ISO 17179:2016(E)
3.19
response time

time interval between the instant when a stimulus is subjected to a specified abrupt change and the

instant when the response reaches and remains within specified limits around its final stable value,

determined as the sum of the lag time and the rise time in the rising mode, and the sum of the lag time

and the fall time in the falling mode
Note 1 to entry: Lag time, rise time and fall time are defined in ISO 9169:2006.
[SOURCE: ISO 9169:2006, 2.2.4]
3.20
span gas

gas or gas mixture used to adjust and check the span point (3.21) on the response line of the

measuring system

Note 1 to entry: This concentration is often chosen around 70 % to 80 % of full scale.

3.21
span point

value of the output quantity (measured signal) of the automated measuring system (3.2) for the purpose

of calibration, adjustment, etc. that represents a correct measured value generated by reference

material (3.16)
3.22
standard uncertainty

uncertainty (3.23) of the result of a measurement expressed as a standard deviation

[SOURCE: ISO/IEC Guide 98-3:2008, 2.3.1]
3.23
uncertainty (of measurement)

parameter, associated with the result of a measurement, that characterizes the dispersion of the values

that could reasonably be attributed to the measurand (3.11)
[SOURCE: ISO/IEC Guide 98-3:2008, 2.2.3]
3.24
validation of an automated measuring system

procedure to check the statistical relationship between values of the measurand (3.11) indicated by the

automated measuring system (3.2) and the corresponding values given by an independent method of

measurement implemented simultaneously at the same measuring point
3.25
zero gas

gas or gas mixture used to establish the zero point (3.26) on a calibration curve within a given

concentration range
[SOURCE: ISO 12039:2001, 3.4.2]
3.26
zero point

specified value of the output quantity (measured signal) of the AMS (3.2) and which, in the absence of

the measured component, represents the zero crossing of the calibration line
4 © ISO 2016 – All rights reserved
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ISO 17179:2016(E)
4 Symbols and abbreviated terms
e Residual (lack-of-fit) at level i
k Coverage factor
n Number of measurements
s Standard deviation of repeatability
Combined uncertainty of NH mass concentration
u()γ
Expanded uncertainty of NH mass concentration
U()γ
M Molar mass of NH (=17,031 g/mol)
c 3
V Molar volume (22,4 l/mol)
Volume fraction of NH
NH mass concentration in mg/m
NH mass concentration at standard conditions in mg/m (273,15 K; 101,325 kPa)

NH mass concentration at reference conditions in mg/m (273,15 K; 101,325 kPa; O and

3 2
H O corrected)
Average of the measured values x
x ith measured value
Average of the measured value at level i
Value estimated by the regression line at level i
AMS Automated measuring system
CL Chemiluminescence
FTIR Fourier transform infrared
GFC Gas filter correlation
NDIR Non-dispersive infrared
NDUV Non-dispersive ultraviolet
QA Quality assurance
QC Quality control
SCR Selective catalytic reduction
SNCR Selective non-catalytic reduction
TLS Tuneable laser spectroscopy
© ISO 2016 – All rights reserved 5
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ISO 17179:2016(E)
5 Principle

This International Standard describes automated measurement systems for sampling, sample

conditioning, and determining NH content in flue gas using instrumental methods (analysers).

There are two types of automated measuring systems:
— extractive systems;
— in situ systems.

With extractive systems, the representative gas sample is taken from the stack with a sampling probe

and conveyed to the analyser through the sampling line and sample gas conditioning system.

In situ systems do not require any sample processing. For the installation of these systems, a

representative place in the stack is to be chosen.

The systems described in this International Standard measure NH concentration using instrumental

methods that shall meet the minimum performance specifications given.
6 Description of the automated measuring systems
6.1 Sampling and sample gas conditioning systems

Since ammonia (NH ) is condensable and highly reactive component, there are many opportunities for

loss of sample integrity due to condensation, deposition or other loss of ammonium compounds in the

sample transport system.

The details of the sampling and sample gas conditioning systems for each of automated measuring

systems are described in Annex A, Annex B, and Annex C.
6.2 Analyser equipment

Examples of the typical analytical methods available are described in Annex A (NO/NO CL technique

and NDUV technique), Annex B (FTIR and NDIR with GFC technique) and Annex C (TLS technique).

Instruments that use these techniques shall meet the performance characteristics as described in

Clause 7.
7 Performance characteristics
7.1 Performance criteria

Table 1 gives the performance characteristics and performance criteria of the analyser and

measurement system to be evaluated during general performance test, by means of ongoing QA/QC

in the laboratory and during field operation. Test procedures for the performance test are specified in

Annex E.
6 © ISO 2016 – All rights reserved
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ISO 17179:2016(E)

Table 1 — Main performance characteristics and criteria of AMS for measurement of ammonia

Performance characteristic Performance criterion Test procedure
Response time ≤400 s E.2
≤900 s

Standard deviation of repeatability in ≤2 % of the upper limit of the lowest E.3.2

laboratory at zero point measuring range used

Standard deviation of repeatability (NH ) in ≤2 % of the upper limit of the lowest E.3.3

laboratory at span point measuring range used
Lack-of-fit ≤ ±2 % of the upper limit of the lowest E.4
measuring range used
Zero drift within 24 h ≤ ±2 % of the upper limit of the lowest E.10
measuring range used
Span drift within 24 h ≤ ±2 % of the upper limit of the lowest E.10
measuring range used

Sensitivity to sample gas pressure, for a ≤ ±3 % of the upper limit of the lowest E.13

pressure change of 2 kPa measuring range used

Zero drift within the period of unattended ≤ ±3 % of the upper limit of the lowest E.11

operation measuring range used

Span drift within the period of unattended ≤ ±3 % of the upper limit of the lowest E.11

operation measuring range used

Sensitivity to ambient temperature, for a ≤ ±3 % of the upper limit of the lowest E.14

change of 10 K in the temperature range measuring range used
specified by the manufacturer

Sensitivity to electric voltage in the voltage ≤ ±2 % of the upper limit of the lowest E.15

range specified by the manufacturer measuring range used per 10 V
Cross-sensitivity ≤4 % of the upper limit of the lowest E.5
measuring range used
NO /NO converter efficiency, if applicable ≥95 % E.6
NH /NO converter efficiency, if applicable ≥90 % E.7
NH /N converter efficiency, if applicable ≥95 % E.7
3 2

Losses and leakage in the sampling line and ≤2 % of the measured value E.8 for losses and

conditioning system E.9 for leakage

Excursion of the measurement beam of ≤2 % of the measured value of the lowest E.12

cross-stack in situ AMS measuring range used
For emission monitoring from deNO systems.

For long term monitoring of changes in the deNO systems, especially the reduction of catalyst activity.

In the case of a nominal supply voltage of 200 V.

The measuring range is defined by two values of the measurand, or quantity to be supplied, within

which the limits of uncertainty of the measuring instrument are specified. The upper limit of the lowest

measuring range used should be set suitable to the application, such that the measurement values lie

within 20 % to 80 % of the measuring range.
7.2 Determination of the performance characteristics
7.2.1 Performance test

The performance characteristics of the AMS shall be determined during the general performance test.

The values of the performance characteristics determined shall meet the performance criteria specified

in Table 1. The procedures for the determination of these performance characteristics are described in

Annex E.

The ambient conditions applied during the general performance test shall be documented.

© ISO 2016 – All rights reserved 7
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ISO 17179:2016(E)

The measurement uncertainty of the AMS measured values shall be calculated in accordance with

ISO 14956 on the basis of the performance characteristics determined during the general performance

test and shall meet the level of uncertainty appropriate for the intended use.
7.2.2 Ongoing quality control

The user shall check specific performance characteristics during ongoing operation of the measuring

system with a periodicity specified in Table 2.

The measurement uncertainty during field application shall be determined by the user of the measuring

system in accordance with applicable international or national standards. For process monitoring (non-

regulatory application), the level of uncertainty shall be appropriate for the intended use. It can be

determined by a direct or an indirect approach for uncertainty estimation as described in ISO 20988.

The uncertainty of the measured values under field operation is not only influenced by the performance

characteristics of the analyser itself but also by uncertainty contributions due to

— the sampling line and conditioning system,
— the site specific conditions, and
— the calibration gases used.
8 Measurement procedure
8.1 General
The AMS shall be operated according to the manufacturer’s instructions.
The QA/QC procedures specified in Clause 9 shall be strictly observed.

During the measurement, the ambient conditions should be in the ranges applied during the general

performance test.
8.2 Choice of the measuring system

To choose an appropriate analyser, sampling line and conditioning unit, the following characteristics of

flue gases should be known before the field operation:
— ambient temperature range;
— temperature of the flue gas;
— water vapour content of the flue gas;
— dust load of the flue gas;
— expected concentration range of NH ;
— expected concentration of potentially interfering substances.

To avoid long response times and memory effects, the sampling line should be as short as possible. If

necessary, a bypass pump should be used. If there is a high dust loading in the sample gas, an appropriate

heated filter shall be used.

Before monitoring emissions, the user shall verify that the necessary QA/QC procedures have been

performed.
[3] [4]
NOTE Information on QA/QC procedures is provided in ISO 14385-1 and ISO 14385-2.
8 © ISO 2016 – All rights reserved
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ISO 17179:2016(E)
8.3 Sampling
8.3.1 Sampling location

The sampling location shall be an available space for the sampling equipment, analyser and possible

sampling platform requirements and construction, making a representative emission measurement

possible and is suitable for the measurement task. In addition, the sampling location shall be chosen

with regard to safety of the personnel, accessibility and availability of electrical power.

8.3.2 Sampling point(s)
It is necessary to ensure that the gas concentrations
...

SLOVENSKI STANDARD
SIST ISO 17179:2019
01-julij-2019
Emisije nepremičnih virov - Določevanje masne koncentracije amoniaka v
odpadnih plinih - Delovne karakteristike avtomatskih merilnih sistemov

Stationary source emissions - Determination of the mass concentration of ammonia in

flue gas - Performance characteristics of automated measuring systems

Émission des sources fixes - Détermination de la concentration massique de l'ammoniac

dans les gaz de combustion - Caractéristiques de performance des systèmes de mesure

automatisés
Ta slovenski standard je istoveten z: ISO 17179:2016
ICS:
13.040.40 Emisije nepremičnih virov Stationary source emissions
SIST ISO 17179:2019 en

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 17179:2019
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SIST ISO 17179:2019
INTERNATIONAL ISO
STANDARD 17179
First edition
2016-07-01
Stationary source emissions —
Determination of the mass
concentration of ammonia in flue
gas — Performance characteristics of
automated measuring systems
Émission des sources fixes — Détermination de la concentration
massique de l’ammoniac dans les gaz de combustion —
Caractéristiques de performance des systèmes de mesure automatisés
Reference number
ISO 17179:2016(E)
ISO 2016
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Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 2

4 Symbols and abbreviated terms ........................................................................................................................................................... 5

5 Principle ........................................................................................................................................................................................................................ 6

6 Description of the automated measuring systems ............................................................................................................ 6

6.1 Sampling and sample gas conditioning systems ........................................................................................................ 6

6.2 Analyser equipment ........................................................................................................................................................................... 6

7 Performance characteristics .................................................................................................................................................................... 6

7.1 Performance criteria .......................................................................................................................................................................... 6

7.2 Determination of the performance characteristics ................................................................................................. 7

7.2.1 Performance test .............................................................................................................................................................. 7

7.2.2 Ongoing quality control ............................................................................................................................................. 8

8 Measurement procedure .............................................................................................................................................................................. 8

8.1 General ........................................................................................................................................................................................................... 8

8.2 Choice of the measuring system .............................................................................................................................................. 8

8.3 Sampling ....................................................................................................................................................................................................... 9

8.3.1 Sampling location ............................................................................................................................................................ 9

8.3.2 Sampling point(s) ............................................................................................................................................................ 9

8.4 Data collection ......................................................................................................................................................................................... 9

8.5 Calculation .................................................................................................................................................................................................. 9

9 Quality assurance and quality control procedures .......................................................................................................10

9.1 General ........................................................................................................................................................................................................10

9.2 Frequency of checks ........................................................................................................................................................................10

9.3 Calibration, validation and measurement uncertainty .....................................................................................11

10 Test report ................................................................................................................................................................................................................11

Annex A (informative) Extractive differential NO measurement technique ..........................................................13

Annex B (informative) Extractive direct NH measurement technique ........................................................................17

Annex C (informative) In situ and direct NH measurement with TLS analyser ..................................................20

Annex D (normative) Operational gases .......................................................................................................................................................24

Annex E (normative) Procedures for determination of the performance characteristics

during the general performance test ...........................................................................................................................................26

Annex F (informative) Examples of the results for the assessment of ammonia AMS ...................................34

Annex G (informative) Calculation of uncertainty of measurement of NH .............................................................36

Bibliography .............................................................................................................................................................................................................................40

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Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards

bodies (ISO member bodies). The work of preparing International Standards is normally carried out

through ISO technical committees. Each member body interested in a subject for which a technical

committee has been established has the right to be represented on that committee. International

organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.

ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of

electrotechnical standardization.

The procedures used to develop this document and those intended for its further maintenance are

described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the

different types of ISO documents should be noted. This document was drafted in accordance with the

editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).

Attention is drawn to the possibility that some of the elements of this document may be the subject of

patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www.iso.org/patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,

as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the

Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.

The committee responsible for this document is ISO/TC 146, Air quality, Subcommittee SC 1, Stationary

source emissions.
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Introduction

Selective Catalytic Reduction (SCR) and Selective Non-Catalytic Reduction (SNCR) NO control systems

are used for emission control of NO in flue gas from power generation plants, waste incinerators and

others. The NO reduction technologies require the injection of ammonia (NH ) and/or urea into flue

x 3

gas. The SCR system is designed to be operated at unreacted NH in flue gas (or remained NH in flue

3 3
3 3

gas) as small as possible (typically below 2 mg/m to 4 mg/m NH concentration) with more than

90 % NO reduction efficiency. The standardization of a measurement method of NH is thus strongly

x 3

desired for efficient operation and maintenance of the NO control systems and for minimization of

environmental impacts due to ammonia and NO .
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INTERNATIONAL STANDARD ISO 17179:2016(E)
Stationary source emissions — Determination of the mass
concentration of ammonia in flue gas — Performance
characteristics of automated measuring systems
1 Scope

This International Standard specifies the fundamental structure and the most important performance

characteristics of automated measuring systems for ammonia (NH ) to be used on stationary source

emissions, for example, combustion plants where SNCR/SCR NO control systems (deNO systems) are

x x

applied. The procedures to determine the performance characteristics are also specified. Furthermore,

it describes methods and equipment to determine NH in flue gases including the sampling system and

sample gas conditioning system.

This International Standard describes extractive systems, based on direct and indirect measurement

methods, and in situ systems, based on direct measurement methods, in connection with a range of

analysers that operate using, for example, the following principles:

— ammonia conversion to, or reaction with NO, followed by chemiluminescence (CL) NO difference

measurement for ammonia (differential NO );

— ammonia conversion to, or reaction with NO, followed by non-dispersive ultraviolet (NDUV)

spectroscopy NO difference measurement for ammonia (differential NO );
x x
— Fourier transform infrared (FTIR) spectroscopy;
— non-dispersive infrared (NDIR) spectroscopy with gas filter correlation (GFC);
— tuneable laser spectroscopy (TLS).

The method allows continuous monitoring with permanently installed measuring systems of NH

emissions, and is applicable to measurements of NH in dry or wet flue gases, for process monitoring,

long term monitoring of the performance of deNO systems and/or emission monitoring.

Other equivalent instrumental methods can be used, provided they meet the minimum requirements

proposed in this International Standard. The measuring system can be calibrated with certified gases,

in accordance with this International Standard, or comparable methods.

The differential NO technique using CL has been successfully tested on some power plants where the

NO concentration and NH concentration in flue gas after deNO systems are up to 50 mg (NO)/m and

x 3 x

10 mg (NH )/m , respectively. AMS based on FTIR, NDIR with GFC and TLS has been used successfully

in this application for measuring ranges as low as 10 mg (NH )/m .
2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are

indispensable for its application. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any amendments) applies.

ISO 9169, Air quality — Definition and determination of performance characteristics of an automatic

measuring system

ISO 14956, Air quality — Evaluation of the suitability of a measurement procedure by comparison with a

required measurement uncertainty
ISO 20988, Air quality — Guidelines for estimating measurement uncertainty
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3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
analyser
analytical part in an extractive or in situ AMS (3.3)
[SOURCE: ISO 12039:2001, 3.3]
3.2
automated measuring system
AMS

measuring system interacting with the flue gas under investigation, returning an output signal

proportional to the physical unit of the measurand (3.11) in unattended operation

Note 1 to entry: In the sense of this International Standard, an AMS is a system that can be attached to a duct or

stack to continuously or intermittently measure the mass concentration of NH passing through the duct.

[SOURCE: ISO 9169:2006, 2.1.2, modified.]
3.3
in situ AMS

non-extractive systems that measure the concentration directly in the duct or stack

Note 1 to entry: In situ systems measure either across the stack or duct or at a point within the duct or stack.

3.4
calibration of an automated measuring system

procedure for establishing the statistical relationship between values of the measurand (3.11) indicated

by the automated measuring system (3.2) and the corresponding values given by an independent method

of measurement implemented simultaneously at the same measuring point
3.5
efficiency of NH /NO
efficiency of a converter which oxidizes NH to NO
3.6
efficiency of NH /N
3 2
efficiency of a converter which reduces NH to N
3 2
3.7
influence quantity

quantity that is not the measurand (3.11) but that affects the result of the measurement

[SOURCE: ISO/IEC Guide 98-3:2008, B.2.10]
3.8
interference
cross-sensitivity

negative or positive effect upon the response of the measuring system, due to a component of the

sample that is not the measurand (3.11)
3.9
interferent
interfering substance

substance present in the air mass under investigation, other than the measurand (3.11), that affects the

response
[SOURCE: ISO 9169:2006, 2.1.12]
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3.10
lack-of-fit

systematic deviation within the range of application between the measurement results obtained

by applying the calibration function to the observed response of the measuring system, measuring

reference materials (3.16) and the corresponding accepted value of such reference materials

Note 1 to entry: Lack of-fit may be a function of the measurement result.

Note 2 to entry: The expression “lack-of-fit” is often replaced in everyday language for linear relations by

“linearity” or “deviation from linearity”.
[SOURCE: ISO 9169:2006, 2.2.9, modified.]
3.11
measurand
particular quantity subject to measurement
[SOURCE: ISO/IEC Guide 98-3:2008, B.2.9, modified.]
3.12
NO /NO converter efficiency
efficiency with which the converter unit of a NO analyser reduces NO to NO
x 2
3.13
performance characteristic
one of the quantities assigned to equipment in order to define its performance

Note 1 to entry: Performance characteristics can be described by values, tolerances, or ranges.

3.14
period of unattended operation

maximum interval of time for which the performance characteristics (3.13) remain within a predefined

range without external servicing, e.g. refill, adjustment

Note 1 to entry: The period of unattended operation is often called maintenance interval.

[SOURCE: ISO 9169:2006, 2.2.11]
3.15
reference gas

gaseous mixture of stable composition used to calibrate the measuring system and which is traceable

to national or international standards
3.16
reference material

substance or mixture of substances with a known concentration within specified limits, or a device of

known characteristics

Note 1 to entry: Normally used are calibration gases, gas cells, gratings, or filters.

[SOURCE: ISO 14385-1:2014, 3.20]
3.17
reference method

measurement method taken as a reference by convention, which gives the accepted reference value of

the measurand (3.11)
3.18
transport time in the measuring system

time period for transportation of the sampled gas from the inlet of the probe to the inlet of the

measurement instrument
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3.19
response time

time interval between the instant when a stimulus is subjected to a specified abrupt change and the

instant when the response reaches and remains within specified limits around its final stable value,

determined as the sum of the lag time and the rise time in the rising mode, and the sum of the lag time

and the fall time in the falling mode
Note 1 to entry: Lag time, rise time and fall time are defined in ISO 9169:2006.
[SOURCE: ISO 9169:2006, 2.2.4]
3.20
span gas

gas or gas mixture used to adjust and check the span point (3.21) on the response line of the

measuring system

Note 1 to entry: This concentration is often chosen around 70 % to 80 % of full scale.

3.21
span point

value of the output quantity (measured signal) of the automated measuring system (3.2) for the purpose

of calibration, adjustment, etc. that represents a correct measured value generated by reference

material (3.16)
3.22
standard uncertainty

uncertainty (3.23) of the result of a measurement expressed as a standard deviation

[SOURCE: ISO/IEC Guide 98-3:2008, 2.3.1]
3.23
uncertainty (of measurement)

parameter, associated with the result of a measurement, that characterizes the dispersion of the values

that could reasonably be attributed to the measurand (3.11)
[SOURCE: ISO/IEC Guide 98-3:2008, 2.2.3]
3.24
validation of an automated measuring system

procedure to check the statistical relationship between values of the measurand (3.11) indicated by the

automated measuring system (3.2) and the corresponding values given by an independent method of

measurement implemented simultaneously at the same measuring point
3.25
zero gas

gas or gas mixture used to establish the zero point (3.26) on a calibration curve within a given

concentration range
[SOURCE: ISO 12039:2001, 3.4.2]
3.26
zero point

specified value of the output quantity (measured signal) of the AMS (3.2) and which, in the absence of

the measured component, represents the zero crossing of the calibration line
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4 Symbols and abbreviated terms
e Residual (lack-of-fit) at level i
k Coverage factor
n Number of measurements
s Standard deviation of repeatability
Combined uncertainty of NH mass concentration
u()γ
Expanded uncertainty of NH mass concentration
U()γ
M Molar mass of NH (=17,031 g/mol)
c 3
V Molar volume (22,4 l/mol)
Volume fraction of NH
NH mass concentration in mg/m
NH mass concentration at standard conditions in mg/m (273,15 K; 101,325 kPa)

NH mass concentration at reference conditions in mg/m (273,15 K; 101,325 kPa; O and

3 2
H O corrected)
Average of the measured values x
x ith measured value
Average of the measured value at level i
Value estimated by the regression line at level i
AMS Automated measuring system
CL Chemiluminescence
FTIR Fourier transform infrared
GFC Gas filter correlation
NDIR Non-dispersive infrared
NDUV Non-dispersive ultraviolet
QA Quality assurance
QC Quality control
SCR Selective catalytic reduction
SNCR Selective non-catalytic reduction
TLS Tuneable laser spectroscopy
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5 Principle

This International Standard describes automated measurement systems for sampling, sample

conditioning, and determining NH content in flue gas using instrumental methods (analysers).

There are two types of automated measuring systems:
— extractive systems;
— in situ systems.

With extractive systems, the representative gas sample is taken from the stack with a sampling probe

and conveyed to the analyser through the sampling line and sample gas conditioning system.

In situ systems do not require any sample processing. For the installation of these systems, a

representative place in the stack is to be chosen.

The systems described in this International Standard measure NH concentration using instrumental

methods that shall meet the minimum performance specifications given.
6 Description of the automated measuring systems
6.1 Sampling and sample gas conditioning systems

Since ammonia (NH ) is condensable and highly reactive component, there are many opportunities for

loss of sample integrity due to condensation, deposition or other loss of ammonium compounds in the

sample transport system.

The details of the sampling and sample gas conditioning systems for each of automated measuring

systems are described in Annex A, Annex B, and Annex C.
6.2 Analyser equipment

Examples of the typical analytical methods available are described in Annex A (NO/NO CL technique

and NDUV technique), Annex B (FTIR and NDIR with GFC technique) and Annex C (TLS technique).

Instruments that use these techniques shall meet the performance characteristics as described in

Clause 7.
7 Performance characteristics
7.1 Performance criteria

Table 1 gives the performance characteristics and performance criteria of the analyser and

measurement system to be evaluated during general performance test, by means of ongoing QA/QC

in the laboratory and during field operation. Test procedures for the performance test are specified in

Annex E.
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Table 1 — Main performance characteristics and criteria of AMS for measurement of ammonia

Performance characteristic Performance criterion Test procedure
Response time ≤400 s E.2
≤900 s

Standard deviation of repeatability in ≤2 % of the upper limit of the lowest E.3.2

laboratory at zero point measuring range used

Standard deviation of repeatability (NH ) in ≤2 % of the upper limit of the lowest E.3.3

laboratory at span point measuring range used
Lack-of-fit ≤ ±2 % of the upper limit of the lowest E.4
measuring range used
Zero drift within 24 h ≤ ±2 % of the upper limit of the lowest E.10
measuring range used
Span drift within 24 h ≤ ±2 % of the upper limit of the lowest E.10
measuring range used

Sensitivity to sample gas pressure, for a ≤ ±3 % of the upper limit of the lowest E.13

pressure change of 2 kPa measuring range used

Zero drift within the period of unattended ≤ ±3 % of the upper limit of the lowest E.11

operation measuring range used

Span drift within the period of unattended ≤ ±3 % of the upper limit of the lowest E.11

operation measuring range used

Sensitivity to ambient temperature, for a ≤ ±3 % of the upper limit of the lowest E.14

change of 10 K in the temperature range measuring range used
specified by the manufacturer

Sensitivity to electric voltage in the voltage ≤ ±2 % of the upper limit of the lowest E.15

range specified by the manufacturer measuring range used per 10 V
Cross-sensitivity ≤4 % of the upper limit of the lowest E.5
measuring range used
NO /NO converter efficiency, if applicable ≥95 % E.6
NH /NO converter efficiency, if applicable ≥90 % E.7
NH /N converter efficiency, if applicable ≥95 % E.7
3 2

Losses and leakage in the sampling line and ≤2 % of the measured value E.8 for losses and

conditioning system E.9 for leakage

Excursion of the measurement beam of ≤2 % of the measured value of the lowest E.12

cross-stack in situ AMS measuring range used
For emission monitoring from deNO systems.

For long term monitoring of changes in the deNO systems, especially the reduction of catalyst activity.

In the case of a nominal supply voltage of 200 V.

The measuring range is defined by two values of the measurand, or quantity to be supplied, within

which the limits of uncertainty of the measuring instrument are specified. The upper limit of the lowest

measuring range used should be set suitable to the application, such that the measurement values lie

within 20 % to 80 % of the measuring range.
7.2 Determination of the performance characteristics
7.2.1 Performance test

The performance characteristics of the AMS shall be determined during the general performance test.

The values of the performance characteristics determined shall meet the performance criteria specified

in Table 1. The procedures for the determination of these performance characteristics are described in

Annex E.

The ambient conditions applied during the general performance test shall be documented.

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The measurement uncertainty of the AMS measured values shall be calculated in accordance with

ISO 14956 on the basis of the performance characteristics determined during the general performance

test and shall meet the level of uncertainty appropriate for the intended use.
7.2.2 Ongoing quality control

The user shall check specific performance characteristics during ongoing operation of the measuring

system with a periodicity specified in Table 2.

The measurement uncertainty during field application shall be determined by the user of the measuring

system in accordance with applicable international or national standards. For process monitoring (non-

regulatory application), the level of uncertainty shall be appropriate for the intended use. It can be

determined by a direct or an indirect approach for uncertainty estimation as described in ISO 20988.

The uncertainty of the measured values under field operation is not only influenced by the performance

characteristics of the analyser itself but also by uncertainty contributions due to

— the sampling line and conditioning system,
— the site specific conditions, and
— the calibration gases used.
8 Measurement procedure
8.1 General
The AMS shall be operated according to the manufacturer’s instructions.
The QA/QC procedures specified in Clause 9 shall be strictly observed.

During the measurement, the ambient conditions should be in the ranges applied during the general

performance test.
8.2 Choice of the measuring system

To choose an appropriate analyser, sampling line and conditioning unit, the following characteristics of

flue gases should be known before the field operatio
...

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