oSIST prEN ISO 17507-2:2024
(Main)Natural gas - Calculation of methane number of gaseous fuels for reciprocating internal combustion engines - Part 2: PKI method (ISO/DIS 17507-2:2024)
Natural gas - Calculation of methane number of gaseous fuels for reciprocating internal combustion engines - Part 2: PKI method (ISO/DIS 17507-2:2024)
Part 2 of ISO 17507 describes the calculation method for the methane number of a gaseous fuel according to the methodology developed by DNV in a consortium with leading engine OEMs and fuel gas suppliers.
Erdgas - Berechnung der Methanzahl von gasförmigen Kraftstoffen für Verbrennungsmotoren - Teil 2: PKI-Verfahren (ISO/DIS 17507-2:2024)
Gaz naturel - Calcul de l'indice de méthane des combustibles gazeux pour les moteurs alternatifs à combustion interne - Partie 2: Méthode PKI (ISO/DIS 17507-2:2024)
[Not translated]
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2024
[Not translated]
Natural gas - Calculation of methane number of gaseous fuels for reciprocating internal
combustion engines - Part 2: PKI method (ISO/DIS 17507-2:2024)
Erdgas - Berechnung der Methanzahl von gasförmigen Kraftstoffen für
Verbrennungsmotoren - Teil 2: PKI-Verfahren (ISO/DIS 17507-2:2024)
Gaz naturel - Calcul de l'indice de méthane des combustibles gazeux pour les moteurs
alternatifs à combustion interne - Partie 2: Méthode PKI (ISO/DIS 17507-2:2024)
Ta slovenski standard je istoveten z: prEN ISO 17507-2
ICS:
75.060 Zemeljski plin Natural gas
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
International
Standard
ISO/DIS 17507-2
ISO/TC 193
Natural gas — Calculation of
Secretariat: NEN
methane number of gaseous
Voting begins on:
fuels for reciprocating internal
2024-10-17
combustion engines —
Voting terminates on:
2025-01-09
Part 2:
PKI method
ICS: 75.060
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
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Reference number
ISO/DIS 17507-2:2024(en)
DRAFT
ISO/DIS 17507-2:2024(en)
International
Standard
ISO/DIS 17507-2
ISO/TC 193
Natural gas — Calculation of
Secretariat: NEN
methane number of gaseous
Voting begins on:
fuels for reciprocating internal
combustion engines —
Voting terminates on:
Part 2:
PKI method
ICS: 75.060
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENTS AND APPROVAL. IT
IS THEREFORE SUBJECT TO CHANGE
AND MAY NOT BE REFERRED TO AS AN
INTERNATIONAL STANDARD UNTIL
PUBLISHED AS SUCH.
This document is circulated as received from the committee secretariat.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
© ISO 2024
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
STANDARDS MAY ON OCCASION HAVE TO
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Published in Switzerland Reference number
ISO/DIS 17507-2:2024(en)
ii
ISO/DIS 17507-2:2024(en)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols and abbreviated terms. 2
5 MN method . 2
PKI
5.1 Introduction .2
5.2 Applicability .2
5.2.1 Standard gaseous fuel composition range .2
5.2.2 Handling of other gaseous fuel components .3
5.3 Methodology to calculate the MN .4
PKI
5.4 Expression of results . .5
5.5 Uncertainty error and bias .5
6 Example calculations . 5
6.1 Example calculation 1 .5
6.2 Example calculation 2 .6
Annex A (normative) Listing of coefficients used in Formula (1) and Formula (4) . 9
Annex B (informative) PKI and MN values for selected gaseous fuel compositions .13
PKI
Annex C (informative) Tools for users of the MN method .15
PKI
Annex D (normative) Uncertainty error and bias .16
Annex E (informative) Natural gas-based fuels for reciprocating internal combustion engines .18
Annex F (informative) Basis of the PKI method . 19
Bibliography .22
iii
ISO/DIS 17507-2:2024(en)
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
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ISO draws attention to the possibility that the implementation of this document may involve the use of (a)
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This document was prepared by Technical Committee ISO/TC 193, Natural gas.
A list of all parts in the ISO 17507 series can be found on the ISO website.
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/DIS 17507-2:2024(en)
Introduction
The globalization of the natural gas market and the drive towards sustainability are increasing the diversity
of the supply of gases to the natural gas infrastructure. For example, the introduction of regasified LNG
can result in higher fractions of non-methane hydrocarbons in the natural gas grid than the traditionally
distributed pipeline gases for which these hydrocarbons have been removed during processing. Also, the
drive towards the introduction of sustainable gaseous fuels such as hydrogen and gases derived from
biomass results in the introduction of “new” gas compositions, containing components that do not occur
in the traditional natural gas supply. Consequently, the increasing variations in gas composition affect
the so-called knock resistance of the gas when used as a fuel which can affect the operational integrity of
reciprocating internal combustion engines.
For the efficient and safe operation of gas engines, it is of great importance to characterize the knock
resistance of gaseous fuels accurately. Engine knock is caused by autoignition of unburned fuel mixture ahead
of this mixture being consumed by the propagating flame. Mild engine knock increases pollutant emissions
accompanied by gradual build-up of component damage and complete engine failure if not counteracted.
Severe knock causes structural damage to critical engine parts, quickly leading to catastrophic engine
failure. To ensure that gas engines are matched with the expected variations in fuel composition, the knock
resistance of the fuel is to be characterized, and subsequently specified, unambiguously.
Traditional methods for characterizing the knock resistance of gaseous fuels, such as the methane number
method developed by AVL in the 1960s, relate the knock propensity of a given fuel with that of an equivalent
[1] [2] [3]
methane/hydrogen mixture using a standardized test engine , and. Several other methane number
methods have since been developed, sometimes based on the approach and/or data from the original
experimental work performed by AVL.
In recognition of the need for standardizing a method for characterizing the knock resistance of gaseous
fuels, several existing methods for calculating a methane number have been considered including the PKI
[4]
method which is described in this document. ISO 17507-1 describes the MNc method.
Methods to calculate a methane number are based on the input of the gas composition under investigation.
While methods may be fundamentally different in their development approach, the methods should ideally
produce similar methane numbers for the range of gas compositions they are valid for. Yet, differences in
outcome can be observed. Engine manufacturers typically determine the calculation method to be used
when specifying a methane number value for their engines as part of their application and warranty
statements. In all cases, when specifying a methane number based on either method, or any other method,
the method used should be noted.
The PKI method has been developed by DNV in a consortium of engine Original Equipment Manufacturers
(OEMs) and natural gas fuel suppliers. The method is based on the physics and chemistry of the air-fuel
mixture during the compression and combustion phases of the engine working cycle that determine engine
knock, using an experimentally verified engine co
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