ISO 29541:2010

INTERNATIONAL ISO
STANDARD 29541
First edition
2010-10-01
Solid mineral fuels — Determination of
total carbon, hydrogen and nitrogen
content — Instrumental method
Combustibles minéraux solides — Dosage du carbone, de l'hydrogène
et de l'azote totaux — Méthode instrumentale

Reference number
©
ISO 2010
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ii © ISO 2010 – All rights reserved

Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Terms and definitions .1
4 Principle.2
5 Reagents.2
6 Apparatus.3
7 Preparation of the test sample.3
8 Procedure.3
8.1 Instrument set-up .3
8.2 Blank analyses.3
8.3 Conditioning and instrument stability check .3
8.4 Calibration.3
8.5 Verification of calibration .4
8.6 Analysis of test samples.4
9 Expression of results.4
10 Precision.5
10.1 Repeatability limit.5
10.2 Reproducibility limit .5
11 Test report.6
Annex A (informative) Recommendations for calibration .7
Bibliography.10

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.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
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.
ISO 29541 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5,
Methods of analysis.
This first edition of ISO 29541 cancels and replaces ISO/TS 12902:2001, which has been technically revised.

iv © ISO 2010 – All rights reserved

Introduction
The reliable determination of total carbon, hydrogen and nitrogen is important for engineering calculations
applied to the combustion of coal. The precise and accurate determination of the carbon content of coal is
essential for carbon accounting purposes.

INTERNATIONAL STANDARD ISO 29541:2010(E)

Solid mineral fuels — Determination of total carbon, hydrogen
and nitrogen content — Instrumental method
WARNING — The use of this International Standard can involve hazardous materials, operations and
equipment. This International Standard does not purport to address all of the safety problems
associated with its use. It is the responsibility of the user of this International Standard to establish
appropriate safety and health practices and determine the applicability of regulatory limitations prior
to use.
1 Scope
This International Standard specifies a method for the determination of total carbon, hydrogen and nitrogen in
coal and coke by instrumental methods.
NOTE This International Standard has been validated for coal only in accordance with the principles of ISO 5725-1.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 687, Solid mineral fuels — Coke — Determination of moisture in the general analysis test sample
ISO 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 5068-2, Brown coals and lignites — Determination of moisture content — Part 2: Indirect gravimetric
method for moisture in the analysis sample
ISO 5069-2, Brown coals and lignites — Principles of sampling — Part 2: Sample preparation for
determination of moisture content and for general analysis
ISO 11722, Solid mineral fuels — Hard coal — Determination of moisture in the general analysis test sample
by drying in nitrogen
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
ISO 13909-6, Hard coal and coke — Mechanical sampling — Part 6: Coke — Preparation of test samples
ISO 18283, Hard coal and coke — Manual sampling
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-2 apply.
4 Principle
Carbon, hydrogen and nitrogen are determined concurrently in a single instrumental procedure. The
quantitative conversion of the carbon, hydrogen and nitrogen into their corresponding gases (CO , H O,
2 2
N /NO ) occurs during combustion of the sample at an elevated temperature in an atmosphere of oxygen.
2 x
Combustion products which would interfere with the subsequent gas analysis are removed. Oxides of nitrogen
(NO ) produced during the combustion are reduced to N before detection. The carbon dioxide, water vapour
x 2
and elemental nitrogen in the gas stream are then determined quantitatively by appropriate instrumental gas
analysis procedures.
5 Reagents
Unless otherwise specified, all reagents shall be of analytical reagent grade.
5.1 Carrier gas, helium or other suitable gas as specified by the instrument manufacturer.
5.2 Oxygen, as specified by the instrument manufacturer.
5.3 Additional reagents, of types and qualities specified by the instrument manufacturer.
5.4 Calibration materials: see Table 1.
Table 1 — Examples of suitable calibration materials and their stoichiometric contents of C, H and N
Mass fraction
%
Name Formula
Carbon Hydrogen Nitrogen
EDTA
C H N O
41,1 5,5 9,6
10 16 2 8
(ethylene diamine tetra-acetic acid)
C H NO
Phenylalanine 65,4 6,7 8,5
9 11 2
C H NO
Acetanilide 71,1 6,7 10,4
8 9
BBOT (CAS-No 7128-64-5)
C H N O S
72,5 6,1 6,5
26 26 2 2
2,5-bis (5′-tert-butyl-2-benzoxazolyl) thiophene
If these materials are accompanied by a traceable certificate of analysis that includes the uncertainty of the
assigned carbon, hydrogen and nitrogen values, then use the certificate values for calibration purposes. If
pure compounds (> 99,5 % purity) are available, use the stoichiometric values. Store these substances in a
desiccator under conditions that maintain the compounds in a dry state.
Table 1 lists those pure substances that were included in the interlaboratory study (ILS) to determine the
calibration requirements and precision of this International Standard. The ILS indicated benzoic acid is not
suitable for calibration. Pure substances other than those listed in Table 1 can be used for calibration provided
the substances meet the purity and calibration requirements of this International Standard.
5.5 Reference materials.
Reference material coal(s) with a certified composition and uncertainty for carbon, hydrogen and nitrogen may
be used as a check to monitor changes in instrument response, which can be affected by constituents not
present in the calibration materials, and to verify the acceptability of nitrogen results. Alternatively, coal of a
known composition can also be used as a check sample. As the bulk composition of coal can change during
storage, coals shall not be used for calibration.
2 © ISO 2010 – All rights reserved

6 Apparatus
6.1 Analytical instrument, consisting of a furnace, gas handling and detection system capable of
analysing a test portion of 6 mg or greater.
6.2 Balance, stand-alone or integrated with the instrument, with a resolution of a least 0,1 % of the test
portion to be weighed.
7 Preparation of the test sample
The sample shall be the general analysis test sample prepared to a nominal top size of 212 µm using
ISO 13909-4, ISO 13909-6, ISO 18283 or ISO 5069-2. Sample preparation procedures are described in
ISO 13909-4 for coal, ISO 13909-6 for coke and ISO 5069-2 for brown coal and lignites.
The moisture content of each test sample and reference material shall be determined in accordance with
ISO 11722 for coal, ISO 687 for coke or ISO 5068-2 for brown coals and lignites. Alternatively, the test sample
and reference material shall be dried prior to analysis.
8 Procedure
8.1 Instrument set-up
Verify that all instrument operation parameters meet the specifications in the instrument operating manual.
Verify the condition and quantity of all chemicals currently in use in the instrument to ensure they are
satisfactory for the number of samples to be analysed. Prior to any analysis, check for, and if necessary
correct, any leaks in the combustion system and carrier gas system.
8.2 Blank analyses
Perform blank analyses daily to establish carbon, hydrogen and nitrogen levels in the combustion and carrier
gases. The level of nitrogen in these gases shall not exceed 1 % of the instrument nitrogen response for the
lowest mass of calibration material. Repeat blank analyses after changing or renewing gases or other
reagents.
8.3 Conditioning and instrument stability check
Condition the instrument in accordance with the manufacturer's instructions (generally by running at least two
test portions of a coal, coke or brown coal or lignite that have a composition typical of the general analysis
sample
...