SIST EN ISO 21404:2020

SLOVENSKI STANDARD
SIST EN ISO 21404:2020
01-april-2020
Nadomešča:
SIST-TS CEN/TS 15370-1:2006
Trdna biogoriva - Določanje taljenja pepela (ISO 21404:2020)
Solid biofuels - Determination of ash melting behaviour (ISO 21404:2020)
Biogene Festbrennstoffe - Bestimmung des Asche-Schmelzverhaltens (ISO 21404:2020)
Biocombustibles solides - Methode de détermination de la fusibilité des cendres (ISO
21404:2020)
Ta slovenski standard je istoveten z: EN ISO 21404:2020
ICS:
75.160.40 Biogoriva Biofuels
SIST EN ISO 21404:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST EN ISO 21404:2020

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SIST EN ISO 21404:2020


EN ISO 21404
EUROPEAN STANDARD

NORME EUROPÉENNE

February 2020
EUROPÄISCHE NORM
ICS 75.160.40; 27.190 Supersedes CEN/TS 15370-1:2006
English Version

Solid biofuels - Determination of ash melting behaviour
(ISO 21404:2020)
Biocombustibles solides - Methode de détermination Biogene Festbrennstoffe - Bestimmung des Asche-
de la fusibilité des cendres (ISO 21404:2020) Schmelzverhaltens (ISO 21404:2020)
This European Standard was approved by CEN on 7 January 2020.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.

This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.





EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21404:2020 E
worldwide for CEN national Members.

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SIST EN ISO 21404:2020
EN ISO 21404:2020 (E)
Contents Page
European foreword . 3

2

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SIST EN ISO 21404:2020
EN ISO 21404:2020 (E)
European foreword
This document (EN ISO 21404:2020) has been prepared by Technical Committee ISO/TC 238 "Solid
biofuels" in collaboration with Technical Committee CEN/TC 335 “Solid biofuels” the secretariat of
which is held by SIS.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by August 2020, and conflicting national standards shall
be withdrawn at the latest by August 2020.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes CEN/TS 15370-1:2006.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the
United Kingdom.
Endorsement notice
The text of ISO 21404:2020 has been approved by CEN as EN ISO 21404:2020 without any modification.

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SIST EN ISO 21404:2020

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SIST EN ISO 21404:2020
INTERNATIONAL ISO
STANDARD 21404
First edition
2020-01
Solid biofuels — Determination of ash
melting behaviour
Biocombustibles solides — Méthode de détermination de la fusibilité
des cendres
Reference number
ISO 21404:2020(E)
©
ISO 2020

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SIST EN ISO 21404:2020
ISO 21404:2020(E)

COPYRIGHT PROTECTED DOCUMENT
© ISO 2020
All rights reserved. Unless otherwise specified, or required in the context of its implementation, 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
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Fax: +41 22 749 09 47
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved

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SIST EN ISO 21404:2020
ISO 21404:2020(E)

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 2
5 Reagents . 3
6 Apparatus . 3
7 Test atmosphere. 4
8 Calibration check . 5
9 Procedure. 5
9.1 Preparation of ash . 5
9.2 Preparation of test pieces . 6
9.3 Determination of characteristic temperatures. 6
10 Precision of the method . 7
11 Test report . 7
Annex A (informative) Definition of shape factor . 8
Annex B (informative) Performance data . 9
Annex C (informative) Examples of the characteristic temperatures .11
Bibliography .13
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ISO 21404:2020(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 voluntary nature of standards, 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.
This document was prepared by Technical Committee ISO/TC 238, Solid biofuels.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/ members .html.
iv © ISO 2020 – All rights reserved

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ISO 21404:2020(E)

Introduction
The test method described in this document provides information about fusion and melting behaviour
of the composite inorganic constituents of the solid biofuel ash at high temperatures.
Ash melting is a complex process where also sintering, shrinkage and expansion or swelling can occur.
The test method is empirical. The ash used for the test is a homogeneous material, prepared from
the fuel by ashing at 550 °C (alternatively, ashing temperatures of 710 °C or 815 °C may be used). The
determination is performed at a controlled rate of heating in a controlled atmosphere. In contrast,
under full-scale conditions, the complex processes of combustion and fusion involve heterogeneous
mixtures of particles, variable heating rates and gas compositions.
The determined characteristic temperatures in the test can be used for comparison of the tendency
of the ashes from different types and qualities of solid biofuels to form fused deposits or to cause bed
agglomeration on heating.
[1] [2]
The method is based on the methods described in DIN 51730:1998 , ISO 540:2008 and CEN/TS
[3]
15370-1 . The terms ash fusibility and ash softening are synonyms to ash melting.
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SIST EN ISO 21404:2020
INTERNATIONAL STANDARD ISO 21404:2020(E)
Solid biofuels — Determination of ash melting behaviour
1 Scope
This document specifies a method for the determination of the characteristic temperatures for the ash
melting behaviour of solid biofuels.
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 16559, Solid biofuels — Terminology, definitions and descriptions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 16559 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
shrinkage starting temperature
SST
temperature is defined as when the area of the test piece falls below 95 % of the original test piece area
at 550 °C (or other ashing temperature used) due to shrinking of the test piece
Note 1 to entry: Shrinkage may be due to liberation of carbon dioxide and volatile alkali compounds. It may also
be due to sintering and may be a first sign of partial melting.
3.2
deformation temperature
DT
temperature at which the first signs of melting occur
Note 1 to entry: It is common that DT will occur shortly before HT/FT. If the test results show a small temperature
difference between SST and DT and a large temperature gap between DT and HT/FT it is advised that the analyst
review the images to verify if the temperature recorded as DT is truly due to melting or if it is a shape change
caused by excessive shrinkage.
Note 2 to entry: Deformation temperature can be seen as rounding of the edges, smoothing of surfaces, expansion
of the cylinder or general changing of the cylinder shape. If the test piece starts to swell or bubble without the
edges being rounded, the temperature is registered as DT (since swelling and bubbling only occur when a fraction
of the ash is melted).
Note 3 to entry: For computerized evaluation a shape factor change can be used to define the deformation
temperature. For definition of shape factor see Annex A.
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3.3
hemisphere temperature
HT
temperature at which the test piece forms approximately a hemisphere i.e. when the height is half of the
base diameter
3.4
flow temperature
FT
temperature at which the ash is spread out over the supporting tile in a layer, the height of which is half
of the height of the test piece at the hemisphere temperature as depicted in Figure 1.
Note 1 to entry: Half of the height of the test piece at the hemisphere temperature has been defined due to
frequently occurring bubbling effects. This is especially important for automatic image evaluation.
Key
1 original shape at reference (ashing) temperature
2 SST, Shrinkage starting temperature
3 DT, Deformation temperature
4 HT, Hemisphere temperature
5 FT, Flow temperature
Figure 1 — Phases which can occur in the ash melting process
4 Principle
Ash from biofuel is prepared under controlled conditions of time and equipment specifications to
a controlled temperature of (550 ± 10) °C. This ash is homogenized, and a test piece is made from
the prepared ash. It is heated up at constant rate and is continuously observed while heated up. The
temperatures at which characteristic changes of the shape occur are recorded. The characteristic
temperatures are defined in Clause 3. Vivid images in Annex C show examples of the characteristic
temperatures.
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ISO 21404:2020(E)

For some ashes produced at 550 °C it can be difficult to determine the deformation temperature due to
liberation of carbon dioxide from carbonates in the ashes, creating strong shrinkage of the test pieces.
Ashing at higher temperatures removes carbonates from the ash but also removes possible contents
of low melting salts. For some purposes (as e.g. searching for glass melting problems regarding wood
pellets) alternative ashing temperatures of (710 ± 10) °C or (815 ± 10) °C may be used provided it is
specified in the test report.
5 Reagents
5.1 Ethanol, with a purity ≥95 %.
5.2 Gold wire, of diameter 0,5 mm or larger, or gold plate, of thickness 0,5 mm to 1,0 mm with a
purity of 99,99 % or a certified melting point (e.g. 1 064 °C).
5.3 Nickel wire, of diameter 0,5 mm or larger, or nickel plate, of thickness 0,5 mm to 1,0 mm, with a
purity of 99,9 % or a certified melting point (e.g. 1 455 °C).
NOTE Nickel is used for calibration in reducing atmosphere only.
5.4 Palladium wire, of diameter 0,5 mm or larger, or palladium plate, of thickness 0,5 mm to 1,0 mm
with a purity of 99,9 % or a certified melting point (e.g. 1 554 °C).
5.5 Carbon dioxide, carbon monoxide, hydrogen or ready mixture of carbon dioxide and carbon
monoxide with 55 % (V/V) to 65 % (V/V) carbon monoxide and 35 % (V/V) to 45 % (V/V) carbon
dioxide or ready mixture of hydrogen and carbon dioxide with 45 % (V/V) to 55 % (V/V) hydrogen
and 45 % (V/V) to 55 % (V/V) carbon dioxide.
6 Apparatus
6.1 Dishes for ashing made of inert material, such as platinum or graphite and of such size that the
2
test portion loading does not exceed 1 g/cm of bottom area can be used for all biomass material. Before
the first use, the dish shall be heated to ashing
...