Solid recovered fuels - Determination of calorific value (ISO 21654:2021)

This Standard specifies a method for the determination of gross calorific value of solid recovered fuels
at constant volume and at the reference temperature 25 °C in a bomb calorimeter calibrated by
combustion of certified benzoic acid.

Feste Sekundärbrennstoffe - Bestimmung des Brennwertes (ISO 21654:2021)

Dieses Dokument legt für feste Sekundärbrennstoffe ein Verfahren zur Bestimmung des Brennwertes bei konstantem Volumen und einer Referenztemperatur von 25 °C fest, wozu ein Verbrennungsgefäß-Kalori¬meter verwendet wird, das durch die Verbrennung zertifizierter Benzoesäure kalibriert ist.

Combustibles solides de récupération - Détermination du pouvoir calorifique (ISO 21654:2021)

Trdna alternativna goriva - Določevanje kalorične vrednosti (ISO 21654:2021)

General Information

Status
Published
Public Enquiry End Date
30-Mar-2020
Publication Date
07-Sep-2021
Technical Committee
Current Stage
6060 - National Implementation/Publication (Adopted Project)
Start Date
02-Aug-2021
Due Date
07-Oct-2021
Completion Date
08-Sep-2021

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SLOVENSKI STANDARD
SIST EN ISO 21654:2021
01-oktober-2021
Nadomešča:
SIST EN 15400:2011
Trdna alternativna goriva - Določevanje kalorične vrednosti (ISO 21654:2021)
Solid recovered fuels - Determination of calorific value (ISO 21654:2021)
Feste Sekundärbrennstoffe - Bestimmung des Brennwertes (ISO 21654:2021)
Combustibles solides de récupération - Détermination du pouvoir calorifique (ISO
21654:2021)
Ta slovenski standard je istoveten z: EN ISO 21654:2021
ICS:
75.160.10 Trda goriva Solid fuels
SIST EN ISO 21654:2021 en,fr,de

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

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SIST EN ISO 21654:2021
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SIST EN ISO 21654:2021
EN ISO 21654
EUROPEAN STANDARD
NORME EUROPÉENNE
July 2021
EUROPÄISCHE NORM
ICS 75.160.10 Supersedes EN 15400:2011
English Version
Solid recovered fuels - Determination of calorific value
(ISO 21654:2021)

Combustibles solides de récupération - Détermination Feste Sekundärbrennstoffe - Bestimmung des

du pouvoir calorifique (ISO 21654:2021) Brennwertes (ISO 21654:2021)
This European Standard was approved by CEN on 19 March 2021.

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

© 2021 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 21654:2021 E

worldwide for CEN national Members.
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SIST EN ISO 21654:2021
EN ISO 21654:2021 (E)
Contents Page

European foreword ....................................................................................................................................................... 3

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SIST EN ISO 21654:2021
EN ISO 21654:2021 (E)
European foreword

This document (EN ISO 21654:2021) has been prepared by Technical Committee ISO/TC 300 "Solid

recovered materials, including solid recovered fuels" in collaboration with Technical Committee

CEN/TC 343 “Solid Recovered Fuels” the secretariat of which is held by SFS.

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 January 2022, and conflicting national standards shall

be withdrawn at the latest by January 2022.

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 EN 15400:2011.

Any feedback and questions on this document should be directed to the users’ national standards

body/national committee. A complete listing of these bodies can be found on the CEN websites.

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 21654:2021 has been approved by CEN as EN ISO 21654:2021 without any modification.

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SIST EN ISO 21654:2021
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SIST EN ISO 21654:2021
INTERNATIONAL ISO
STANDARD 21654
First edition
2021-06
Solid recovered fuels — Determination
of calorific value
Combustibles solides de récupération — Détermination du pouvoir
calorifique
Reference number
ISO 21654:2021(E)
ISO 2021
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SIST EN ISO 21654:2021
ISO 21654:2021(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2021

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
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2021 – All rights reserved
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SIST EN ISO 21654:2021
ISO 21654:2021(E)
Contents Page

Foreword ..........................................................................................................................................................................................................................................v

Introduction ................................................................................................................................................................................................................................vi

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

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

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 2

4.1 Gross calorific value ............................................................................................................................................................................ 2

4.2 Net calorific value ................................................................................................................................................................................. 3

5 Reagents ........................................................................................................................................................................................................................ 3

6 Laboratory conditions .................................................................................................................................................................................... 4

7 Apparatus ..................................................................................................................................................................................................................... 5

7.1 General ........................................................................................................................................................................................................... 5

7.2 Auxiliary equipment ........................................................................................................................................................................... 7

7.3 Balances ........................................................................................................................................................................................................ 7

8 Preparation of test sample ......................................................................................................................................................................... 8

9 Calorimetric procedure ................................................................................................................................................................................. 8

9.1 General ........................................................................................................................................................................................................... 8

9.2 Preparing the combustion vessel for measurement ............................................................................................... 9

9.2.1 General procedure .......................................................................................................................................................... 9

9.2.2 Using combustion aids .............................................................................................................................................10

9.3 Assembling the calorimeter ......................................................................................................................................................11

9.4 Combustion reaction and temperature measurements ....................................................................................11

9.5 Analysis of products of combustion ...................................................................................................................................12

9.6 Corrected temperature rise θ ................................................................................................................................................12

9.6.1 Observed temperature rise ..................................................................................................................................12

9.6.2 Isoperibol and static-jacket calorimeters ................................................................................................12

9.6.3 Adiabatic calorimeters .............................................................................................................................................14

9.6.4 Thermometer corrections ....................................................................................................................................14

9.7 Reference temperature .................................................................................................................................................................14

10 Calibration ...............................................................................................................................................................................................................14

10.1 Principle .....................................................................................................................................................................................................14

10.2 Calibration reference ......................................................................................................................................................................15

10.2.1 Certification conditions...........................................................................................................................................15

10.2.2 Calibration conditions ..............................................................................................................................................15

10.3 Valid working range of the effective heat capacity ε .........................................................................................15

10.4 Ancillary contributions .................................................................................................................................................................16

10.5 Calibration procedure ....................................................................................................................................................................16

10.6 Calculation of effective heat capacity for the individual experiment ....................................................17

10.6.1 Constant mass-of-calorimeter-water basis ............................................................................................17

10.6.2 Constant total-calorimeter-mass basis ......................................................................................................17

10.7 Precision of the mean value of the effective heat capacity ε ......................................................................18

10.7.1 Constant value of ε ........................................................................................................................................... .........18

10.7.2 ε as a function of the observed temperature rise...........................................................................19

10.8 Repetition of the determination of effective heat capacity ............................................................................19

11 Gross calorific value .......................................................................................................................................................................................19

11.1 General ........................................................................................................................................................................................................19

11.2 Combustion .............................................................................................................................................................................................20

11.3 Calculation of gross calorific value .....................................................................................................................................20

© ISO 2021 – All rights reserved iii
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SIST EN ISO 21654:2021
ISO 21654:2021(E)

11.3.1 General...................................................................................................................................................................................20

11.3.2 Constant mass-of-calorimeter-water basis ............................................................................................20

11.3.3 Constant total-calorimeter-mass basis ......................................................................................................22

11.3.4 ε as a function of the observed temperature rise...........................................................................23

11.4 Expression of results .......................................................................................................................................................................23

11.5 Calculation to other bases ..........................................................................................................................................................23

12 Precision ....................................................................................................................................................................................................................24

12.1 Repeatability limit .............................................................................................................................................................................24

12.2 Reproducibility limit .......................................................................................................................................................................24

13 Calculation of net calorific value at constant pressure .............................................................................................24

13.1 General ........................................................................................................................................................................................................24

13.2 Calculations .............................................................................................................................................................................................24

14 Test report ................................................................................................................................................................................................................25

Annex A (normative) Adiabatic combustion vessel calorimeters .......................................................................................27

Annex B (normative) Isoperibol and static-jacket combustion vessel calorimeters ......................................31

Annex C (normative) Automated combustion vessel calorimeters ...................................................................................36

Annex D (normative) Removed ash contributors ................................................................................................................................39

Annex E (informative) Checklists for the design and procedures of combustion experiments ...........42

Annex F (informative) Examples to illustrate the main calculations used in this document if

an automated (adiabatic) combustion vessel calorimeter is used for determinations ..........47

Annex G (informative) List of symbols used in this document ...............................................................................................50

Annex H (informative) Flow chart for a routine calorific value determination ...................................................53

Annex I (informative) Interlaboratory test results .............................................................................................................................54

Annex J (informative) Additional terms for the basis of results expression ............................................................57

Annex K (informative) Environmental aspects .......................................................................................................................................58

Bibliography .............................................................................................................................................................................................................................60

iv © ISO 2021 – All rights reserved
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SIST EN ISO 21654:2021
ISO 21654:2021(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 of 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 www .iso .org/

iso/ foreword .html.

This document was prepared by Technical Committee ISO/TC 300, Solid recovered fuels, in collaboration

with the European Committee for Standardization (CEN) Technical Committee CEN/TC 343, Solid

Recovered Fuels, in accordance with the Agreement on technical cooperation between ISO and CEN

(Vienna Agreement).

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.
© ISO 2021 – All rights reserved v
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SIST EN ISO 21654:2021
ISO 21654:2021(E)
Introduction
[1]
This document is based on EN 15400 .

The result obtained is the gross calorific value of the sample analysed at constant volume with all the

water of the combustion products as liquid water. In practice, solid recovered fuels are burned at a

constant (atmospheric) pressure and the water is either not condensed (removed as vapour with the

flue gases) or condensed. Under both conditions, the operative heat of combustion to be used is the net

calorific value of the fuel at constant pressure. The net calorific value at constant volume can also be

used; Formulas are given for calculating both values.

General principles and procedures for the calibrations and the solid recovered fuels experiments are

presented in the main part of this document, whereas those pertaining to the use of a particular type of

calorimetric instrument are specified in Annexes A to C. Annex D contains the formulae to calculate the

removed ash contributors. Annex E contains checklists for performing calibration and fuel experiments

using specified types of calorimeters. Annex F gives examples to illustrate some of the calculations.

vi © ISO 2021 – All rights reserved
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SIST EN ISO 21654:2021
INTERNATIONAL STANDARD ISO 21654:2021(E)
Solid recovered fuels — Determination of calorific value

WARNING — Strict adherence to all of the provisions specified in this document should ensure

against explosive rupture of the combustion vessel, or a blow-out, provided that the vessel is of

standard design and construction and in good mechanical condition.
1 Scope

This document specifies a method for the determination of gross calorific value of solid recovered

fuels at constant volume and at the reference temperature 25 °C in a combustion vessel calorimeter

calibrated by combustion of certified benzoic acid.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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 10304-1, Water quality — Determination of dissolved anions by liquid chromatography of ions —

Part 1: Determination of bromide, chloride, fluoride, nitrate, nitrite, phosphate and sulfate

ISO 16993, Solid biofuels — Conversion of analytical results from one basis to another

ISO 21637, Solid recovered fuels — Vocabulary

ISO 21644, Solid recovered fuels — Methods for the determination of biomass content

ISO 21646, Solid recovered fuels — Sample preparation

ISO 21660-3, Solid recovered fuels — Determination of moisture content using the oven dry method —

Part 3: Moisture in general analysis sample

EN 15358, Solid recovered fuels — Quality management systems — Particular requirements for their

application to the production of solid recovered fuels
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 21637 and the following apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at http:// www .electropedia .org/
3.1
gross calorific value at constant volume

absolute value of the specific energy of combustion, in Joules, for unit mass of a solid recovered fuel

burned in oxygen in a calorimetric combustion vessel under the conditions specified

Note 1 to entry: The products of combustion are assumed to consist of gaseous oxygen, nitrogen, carbon dioxide

and sulfur dioxide, of liquid water (in equilibrium with its vapour) saturated with carbon dioxide under the

conditions of the combustion vessel reaction, and of solid ash, all at the reference temperature (3.4).

1) Under preparation. Stage at the time of publication: ISO/DIS 21646:2021.
© ISO 2021 – All rights reserved 1
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SIST EN ISO 21654:2021
ISO 21654:2021(E)
3.2
net calorific value at constant volume

absolute value of the specific energy of combustion, in Joules, for unit mass of a solid recovered fuel

burned in oxygen under conditions of constant volume and such that all the water of the reaction

products remains as water vapour (in a hypothetical state at 0,1 MPa), the other products being, as for

the gross calorific value, all at the reference temperature (3.4)
3.3
net calorific value at constant pressure

absolute value of the specific heat (enthalpy) of combustion, in Joules, for unit mass of a solid recovered

fuel burned in oxygen at constant pressure under such conditions that all the water of the reaction

products remains as water vapour (at 0,1 MPa), the other products being as for the gross calorific value,

all at the reference temperature (3.4)
3.4
reference temperature

international reference temperature for thermo-chemistry of 25 °C is adopted as the reference

temperature for calorific values (see 9.7)

Note 1 to entry: The temperature dependence of the calorific value of solid recovered fuels is small [less than 1 J/

(g ⋅ K)].
3.5
effective heat capacity of the calorimeter
amount of energy required to cause unit change in temperature of the calorimeter
3.6
corrected temperature rise

change in calorimeter temperature caused solely by the processes taking place within the combustion

vessel calorimeter

Note 1 to entry: It is the total observed temperature rise corrected for heat exchange, stirring power etc. (see 9.6).

Note 2 to entry: The change in temperature can be expressed in terms of other units: resistance of a platinum or

thermistor thermometer, frequency of a quartz crystal resonator etc., provided that a functional relationship is

established between this quantity and a change in temperature. The effective heat capacity of the calorimeter (3.5)

can be expressed in units of energy per such an arbitrary unit. Criteria for the required linearity and closeness in

conditions between calibrations and fuel experiments are given in 9.3.

Note 3 to entry: A list of the symbols used and their definitions is given in Annex G.

Note 4 to entry: Annex J explains additional relevant terms that could be of interest, more specifically in

association to Annex D. The terms can provide some clarification in certain cases.

3.7
removed ash contributors
rac

coarse inert material (i.e. metals, glass, stones, tiles, etc.) removed from the sample before preparation,

in order to avoid damage to the preparation equipment

Note 1 to entry: The removed ash contributors (rac), after sample pre-drying, are taken into account for the

calculation of the ash, carbon, hydrogen, nitrogen and sulfur content in the analysed sample.

Note 2 to entry: See Annex D for further information.
4 Principle
4.1 Gross calorific value

A weighed portion of the analysis sample of a solid recovered fuel is burned in high-pressure oxygen

in a combustion vessel calorimeter under specified conditions. The effective heat capacity of the

2 © ISO 2021 – All rights reserved
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SIST EN ISO 21654:2021
ISO 21654:2021(E)

calorimeter is determined in calibration experiments by the combustion of certified benzoic acid under

similar conditions, accounted for in the certificate. The corrected temperature rise is established from

observations of temperature before, during and after the combustion reaction takes place. The duration

and frequency of the temperature observations depend on the type of calorimeter used. Water is added

to the vessel initially to give a saturated vapour phase prior to combustion (see 9.2.1 and 10.2.2),

thereby allowing
...

SLOVENSKI STANDARD
oSIST prEN ISO 21654:2020
01-marec-2020
Trdna alternativna goriva - Določevanje kalorične vrednosti (ISO/DIS 21654:2019)
Solid recovered fuels - Determination of calorific value (ISO/DIS 21654:2019)
Feste Sekundärbrennstoffe - Bestimmung des Brennwertes (ISO/DIS 21654:2019)

Combustibles solides de récupération - Détermination du pouvoir calorifique (ISO/DIS

21654:2019)
Ta slovenski standard je istoveten z: prEN ISO 21654
ICS:
75.160.10 Trda goriva Solid fuels
oSIST prEN ISO 21654:2020 en,fr,de

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

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oSIST prEN ISO 21654:2020
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oSIST prEN ISO 21654:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 21654
ISO/TC 300 Secretariat: SFS
Voting begins on: Voting terminates on:
2019-12-19 2020-03-12
Solid recovered fuels — Determination of calorific value
Combustibles solides de récupération — Détermination du pouvoir calorifique
ICS: 75.160.10
THIS DOCUMENT IS A DRAFT CIRCULATED
This document is circulated as received from the committee secretariat.
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
ISO/CEN PARALLEL PROCESSING
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 21654:2019(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
PROVIDE SUPPORTING DOCUMENTATION. ISO 2019
---------------------- Page: 3 ----------------------
oSIST prEN ISO 21654:2020
ISO/DIS 21654:2019(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2019

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 2019 – All rights reserved
---------------------- Page: 4 ----------------------
oSIST prEN ISO 21654:2020
ISO/DIS 21654:2019(E)
Contents

Foreword ......................................................................................................................................................................... vi

Introduction .................................................................................................................................................................. vii

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

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

3 Terms and definitions ..........................................................................................................................................1

4 Principle ....................................................................................................................................................................3

4.1 Gross calorific value ..............................................................................................................................................3

4.2 Net calorific value ..................................................................................................................................................3

5 Reagents ....................................................................................................................................................................3

6 Apparatus .................................................................................................................................................................4

6.1 General .......................................................................................................................................................................4

6.2 Calorimeter with thermostat .............................................................................................................................5

7 Preparation of test sample .................................................................................................................................8

8 Calorimetric procedure .......................................................................................................................................8

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

8.2 Preparing the bomb for measurement ..........................................................................................................9

8.2.1 General procedure ..........................................................................................................................................9

8.2.2 Using combustion aids ................................................................................................................................ 10

8.3 Assembling the calorimeter ............................................................................................................................ 11

8.4 Combustion reaction and temperature measurements........................................................................ 11

8.5 Analysis of products of combustion ............................................................................................................. 12

8.6 Corrected temperature rise  ......................................................................................................................... 12

8.6.1 Observed temperature rise ....................................................................................................................... 12

8.6.2 Isoperibol and static-jacket calorimeters ............................................................................................ 13

8.6.3 Adiabatic calorimeters ............................................................................................................................... 14

8.6.4 Thermometer corrections ......................................................................................................................... 14

8.7 Reference temperature ..................................................................................................................................... 14

9 Calibration ............................................................................................................................................................. 14

9.1 Principle ................................................................................................................................................................. 14

9.2 Calibration reference ........................................................................................................................................ 15

9.2.1 Certification conditions .............................................................................................................................. 15

9.2.2 Calibration conditions ................................................................................................................................ 15

9.3 Valid working range of the effective heat capacity 𝜀 .............................................................................. 15

9.4 Ancillary contributions ..................................................................................................................................... 16

9.5 Calibration procedure ....................................................................................................................................... 16

9.6 Calculation of effective heat capacity for the individual experiment .............................................. 17

9.6.1 Constant mass-of-calorimeter-water basis ......................................................................................... 17

9.6.2 Constant total-calorimeter-mass basis ................................................................................................. 18

9.7 Precision of the mean value of the effective heat capacity 𝜀 ............................................................... 19

9.7.1 Constant value of 𝜀 ........................................................................................................................................ 19

9.7.2 𝜀 as a function of the observed temperature rise .............................................................................. 19

9.8 Repetition of the determination of effective heat capacity ................................................................. 19

10 Gross calorific value ........................................................................................................................................... 20

© ISO 2019 – All rights reserved
iii
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oSIST prEN ISO 21654:2020
ISO/DIS 21654:2019(E)

10.1 General ............................................................................................................................................................. 20

10.2 Combustion .................................................................................................................................................... 20

10.3 Calculation of gross calorific value ........................................................................................................ 20

10.3.1 General ............................................................................................................................................................. 20

10.3.2 Constant mass-of-calorimeter-water basis ......................................................................................... 21

10.3.3 Constant total-calorimeter-mass basis ................................................................................................ 22

10.3.4 𝜀 as a function of the observed temperature rise ............................................................................. 23

10.4 Expression of results ................................................................................................................................... 23

10.5 Calculation to other bases ......................................................................................................................... 24

11 Precision ................................................................................................................................................................ 24

11.1 Repeatability limit ....................................................................................................................................... 24

11.2 Reproducibility limit ................................................................................................................................... 24

12 Calculation of net calorific value at constant pressure ......................................................................... 24

12.1 General ............................................................................................................................................................. 24

12.2 Calculations .................................................................................................................................................... 25

13 Test report ............................................................................................................................................................ 26

Annex A (normative) Adiabatic bomb calorimeters ..................................................................................... 27

A.1 Principle................................................................................................................................................................. 27

A.2 Sources of deviation for the real calorimeter .......................................................................................... 27

A.3 Adiabatic conditions .......................................................................................................................................... 28

A.3.1 Thermostat ..................................................................................................................................................... 28

A.3.2 Adiabatic control .......................................................................................................................................... 28

A.4 Initial steady state and length of the main period .................................................................................. 28

A.5 Correction for drift at the final temperature ............................................................................................ 29

A.6 Strategy for checking on bias ......................................................................................................................... 30

Annex B (normative) Isoperibol and static-jacket bomb calorimeters ................................................. 31

B.1 Principle................................................................................................................................................................. 31

B.2 Sources of deviation for the real calorimeter .......................................................................................... 32

B.3 Choice of jacket temperature ......................................................................................................................... 33

B.4 Rating periods ..................................................................................................................................................... 33

B.4.1 Initial steady state and fore period ....................................................................................................... 33

B.4.2 After period and length of the main period ........................................................................................ 33

B.5 Calculation of the corrected temperature rise B .................................................................................... 34

B.5.1 General ............................................................................................................................................................. 34

B.5.2 Regnault-Pfaundler method ..................................................................................................................... 34

B.5.3 Dickinson extrapolation method ............................................................................................................ 35

Annex C (normative) Automated bomb calorimeters .................................................................................. 36

C.1 The instrument .................................................................................................................................................... 36

C.2 Calibration ............................................................................................................................................................ 36

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C.3 Precision requirements for calibrations .................................................................................................... 37

C.4 Comparability of calibration and fuel experiments ............................................................................... 37

C.5 Documentation and print-out ........................................................................................................................ 38

C.6 Precision requirements for fuel experiments .......................................................................................... 38

Annex D (normative) Removed ash contributors .......................................................................................... 39

D.1 Calculations: Calorific value I after removed ash contributors.......................................................... 39

D.2 Calculations: Calorific value II without removed ash contributors .................................................. 40

Annex E (informative) Checklists for the design and procedures of combustion

experiments .................................................................................................................................................... 41

E.1 Introduction .......................................................................................................................................................... 41

E.2 Choice of general parameters ......................................................................................................................... 41

E.3 Adiabatic calorimeters ...................................................................................................................................... 42

E.3.1 Determination of the corrected temperature rise  ........................................................................ 42

E.3.2 Evaluation of the effective heat capacity  ........................................................................................... 42

E.3.3 The gross calorific value at constant volume q .......................................................................... 43

V,gr

E.4 Isoperibol calorimeters .................................................................................................................................... 43

E.4.1 Determination of the corrected temperature rise  ........................................................................ 43

E.4.2 Evaluation of the effective heat capacity  ........................................................................................... 44

E.4.3 The gross calorific value at constant volume q .......................................................................... 45

V,gr

E.5 Automated bomb calorimeters ...................................................................................................................... 45

Annex F (informative) Examples to illustrate the main calculations used in this document if

an automated (adiabatic) bomb calorimeter is used for determinations ............................... 46

F.1 Gross calorific value at constant volume .................................................................................................... 46

F.2 Gross calorific value at constant pressure ................................................................................................. 47

F.3 Net calorific value ............................................................................................................................................... 48

F.3.1 Net calorific value at constant volume .................................................................................................. 48

F.3.2 Net calorific value at constant pressure ............................................................................................... 48

F.4 Use of typical or default values to calculate calorific values ............................................................... 48

Annex G (informative) List of symbols used in this document .................................................................. 50

Annex H (informative) Flow chart for a routine calorific value determination ................................. 53

Annex I (informative) Interlaboratory test results ....................................................................................... 54

Annex J (informative) Environmental aspects ................................................................................................ 57

Bibliography ................................................................................................................................................................. 59

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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 of 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

www.iso.org/iso/foreword.html.

This document was prepared by Technical Committee ISO/TC 300, Solid recovered fuels.

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.
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Introduction
This document is based on EN 15400.

The result obtained is the gross calorific value of the sample analysed at constant volume with all the

water of the combustion products as liquid water. In practice, solid recovered fuels are burned at a

constant (atmospheric) pressure and the water is either not condensed (removed as vapour with the flue

gases) or condensed. Under both conditions, the operative heat of combustion to be used is the net

calorific value of the fuel at constant pressure. The net calorific value at constant volume can also be used;

equations are given for calculating both values.

General principles and procedures for the calibrations and the solid recovered fuels experiments are

presented in the normative text, whereas those pertaining to the use of a particular type of calorimetric

instrument are specified in Annexes A to C. Annex D contains the formula to calculate the removed ash

contributors. Annex E contains checklists for performing calibration and fuel experiments using specified

types of calorimeters. Annex F gives examples to illustrate some of the calculations.

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DRAFT INTERNATIONAL STANDARD ISO/DIS 21654:2019(E)
Solid recovered fuels — Determination of calorific value

WARNING — Strict adherence to all of the provisions specified in this document should ensure

against explosive rupture of the bomb, or a blow-out, provided that the bomb is of standard design

and construction and in good mechanical condition.
1 Scope

This document specifies a method for the determination of gross calorific value of solid recovered fuels

at constant volume and at the reference temperature 25 °C in a bomb calorimeter calibrated by

combustion of certified benzoic acid.
2 Normative references

The following documents are referred to in the text in such a way that some or all of their content

constitutes requirements 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.

EN 15296, Solid biofuels — Conversion of analytical results from one basis to another

EN 15358, Solid recovered fuels — Quality management systems — Particular requirements for their

application to the production of solid recovered fuels

EN 15440, Solid recovered fuels — Methods for the determination of biomass content

EN 15443, Solid recovered fuels — Methods for the preparation of the laboratory sample

EN ISO 10304-1, Water quality — Determination of dissolved anions by liquid chromatography of ions —

Part 1: Determination of bromide, chloride, fluoride, nitrate, nitrite, phosphate and sulfate (ISO 10304-1)

ISO/DIS 21637, Solid recovered fuels — Terminology, definitions and descriptions

ISO/DIS 21660-3, Solid recovered fuels — Determination of moisture content using the oven dry method —

Part 3: Moisture in general analysis sample
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO/DIS 21637 and the following

apply.

ISO and IEC maintain terminological databases for use in standardization at the following addresses:

⎯ IEC Electropedia: available at http://www.electropedia.org/

ISO/CD 21644:2019 "Solid recovered fuels — Method for the determination of biomass content" is currently

being processed for the preparation of the "DIS"-enquiry.

ISO/CD 21646:2019 "Solid recovered fuels — Sample preparation" is currently being processed for the

preparation of the "DIS"-enquiry.
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⎯ ISO Online browsing platform: available at http://www.iso.org/obp
3.1
gross calorific value at constant volume

absolute value of the specific energy of combustion, in Joules, for unit mass of a solid recovered fuel

burned in oxygen in a calorimetric bomb under the conditions specified

Note 1 to entry: The products of combustion are assumed to consist of gaseous oxygen, nitrogen, carbon dioxide

and sulphur dioxide, of liquid water (in equilibrium with its vapour) saturated with carbon dioxide under the

conditions of the bomb reaction, and of solid ash, all at the reference temperature.

3.2
net calorific value at constant volume

absolute value of the specific energy of combustion, in Joules, for unit mass of a solid recovered fuel

burned in oxygen under conditions of constant volume and such that all the water of the reaction

products remains as water vapour (in a hypothetical state at 0,1 MPa), the other products being, as for

the gross calorific value, all at the reference temperature
3.3
net calorific value at constant pressure

absolute value of the specific heat (enthalpy) of combustion, in Joules, for unit mass of a solid recovered

fuel burned in oxygen at constant pressure under such conditions that all the water of the reaction

products remains as water vapour (at 0,1 MPa), the other products being as for the gross calorific value,

all at the reference temperature
3.4
reference temperature

international reference temperature for thermo-chemistry of 25 °C is adopted as the reference

temperature for calorific values (see 8.7)

Note 1 to entry: The temperature dependence of the calorific value of solid recovered fuels is small [less than

1 J/(g  K)].
3.5
effective heat capacity of the calorimeter
amount of energy required to cause unit change in temperature of the calorimeter
3.6
corrected temperature rise

change in calorimeter temperature caused solely by the processes taking place within the bomb

calorimeter

Note 1 to entry: It is the total observed temperature rise corrected for heat exchange, stirring power etc. (see 8.6).

Note 2 to entry: The change in temperature can be expressed in terms of other units: resistance of a platinum or

thermistor thermometer, frequency of a quartz crystal resonator etc., provided that a functional relationship is

established between this quantity and a change in temperature. The effective heat capacity of the calorimeter can

be expressed in units of energy per such an arbitrary unit. Criteria for the required linearity and closeness in

conditions between calibrations and fuel experiments are given in 9.3.

Note 3 to entry: A list of the symbols used and their definitions is given in Annex G.

3.7
Removed ash contributors
rac
coarse inert material (i.
...

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