SIST EN ISO 23306:2020
(Main)Specification of liquefied natural gas as a fuel for marine applications (ISO 23306:2020)
Specification of liquefied natural gas as a fuel for marine applications (ISO 23306:2020)
This document will specify the requirements for LNG for use as a fuel in marine engines. It will define the required values for all relevant parameters and the test method for each of these parameters
Festlegungen für Flüssigerdgas als Kraftstoff für marine Anwendungen (ISO 23306:2020)
Dieses Dokument legt die Anforderungen an die Beschaffenheit von Flüssigerdgas fest, das als Kraftstoff für marine Anwendungen verwendet wird. Es definiert die relevanten Parameter für die Messung sowie die geforderten Werte und die Bezugsprüfverfahren für alle diese Parameter.
Dieses Dokument gilt für LNG aus beliebigen Quellen, z. B. aus herkömmlichen Lagerstätten, Schiefergas, Kohlenflöz-Methan (Flözgas), Biomethan, synthetisches Methan. In diesem Dokument beschriebenes LNG kann aus dem Syntheseprozess von fossilen Brennstoffen oder erneuerbaren Energieträgern stammen.
Dieses Dokument nennt die geforderten Festlegungen für Kraftstoffe zum Zeitpunkt und am Ort des eichpflichtigen Verkehrs (an der Übergabestelle).
Spécification du gaz naturel liquéfié comme carburant pour les applications maritimes (ISO 23306:2020)
Le présent document spécifie les exigences de qualité applicables au gaz naturel liquéfié (GNL) utilisé comme carburant pour les applications maritimes. Il définit les paramètres pertinents à mesurer ainsi que les valeurs requises et les méthodes d'essai de référence pour l'ensemble de ces paramètres.
Le présent document s'applique au GNL provenant de toute source, par exemple : le gaz issu de réservoirs classiques, le gaz de schiste, le gaz de charbon, le biométhane, le méthane de synthèse. Le GNL décrit dans le présent document peut provenir d'un processus de synthèse à partir de carburants fossiles ou de sources renouvelables.
Le présent document identifie les spécifications requises pour les carburants livrés au moment et au lieu du transfert de propriété (au point de livraison).
Specifikacija utekočinjenega zemeljskega plina kot goriva za uporabo v pomorstvu (ISO 23306:2020)
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 23306:2020
01-december-2020
Specifikacija utekočinjenega zemeljskega plina kot goriva za uporabo v pomorstvu
(ISO 23306:2020)
Specification of liquefied natural gas as a fuel for marine applications (ISO 23306:2020)
Festlegungen für Flüssigerdgas als Kraftstoff für marine Anwendungen (ISO
23306:2020)
Spécification du gaz naturel liquéfié comme carburant pour les applications maritimes
(ISO 23306:2020)
Ta slovenski standard je istoveten z: EN ISO 23306:2020
ICS:
75.160.30 Plinska goriva Gaseous fuels
SIST EN ISO 23306:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 23306:2020
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SIST EN ISO 23306:2020
EN ISO 23306
EUROPEAN STANDARD
NORME EUROPÉENNE
November 2020
EUROPÄISCHE NORM
ICS 75.160.30
English Version
Specification of liquefied natural gas as a fuel for marine
applications (ISO 23306:2020)
Spécification du gaz naturel liquéfié comme carburant Festlegungen für Flüssigerdgas als Kraftstoff für
pour les applications maritimes (ISO 23306:2020) marine Anwendungen (ISO 23306:2020)
This European Standard was approved by CEN on 22 September 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 23306:2020 E
worldwide for CEN national Members.
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SIST EN ISO 23306:2020
EN ISO 23306:2020 (E)
Contents Page
European foreword . 3
2
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SIST EN ISO 23306:2020
EN ISO 23306:2020 (E)
European foreword
This document (EN ISO 23306:2020) has been prepared by Technical Committee ISO/TC 28 "Petroleum
and related products, fuels and lubricants from natural or synthetic sources" in collaboration with
Technical Committee CEN/TC 408 “Natural gas and biomethane for use in transport and biomethane for
injection in the natural gas grid” the secretariat of which is held by AFNOR.
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 May 2021, and conflicting national standards shall be
withdrawn at the latest by May 2021.
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.
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 23306:2020 has been approved by CEN as EN ISO 23306:2020 without any modification.
3
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SIST EN ISO 23306:2020
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SIST EN ISO 23306:2020
INTERNATIONAL ISO
STANDARD 23306
First edition
2020-10
Specification of liquefied natural gas
as a fuel for marine applications
Spécification du gaz naturel liquéfié comme carburant pour les
applications maritimes
Reference number
ISO 23306:2020(E)
©
ISO 2020
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SIST EN ISO 23306:2020
ISO 23306:2020(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
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Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii © ISO 2020 – All rights reserved
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope .1
2 Normative references .1
3 Terms and definitions .1
4 General requirements .2
5 Sampling .3
6 Requirements, limit values and related test methods .3
7 Main compounds removed by liquefaction process .4
Annex A (normative) Propane knock index: Methane number calculation method .6
Annex B (informative) Examples of LNG composition .12
Annex C (informative) Methane number (knock resistance) and Wobbe index (thermal
input through a restriction) .15
Annex D (informative) LNG ageing along the bunkering chain .17
Annex E (informative) Particles .18
Annex F (informative) Melting and boiling points of pure components and impurities that
can be present in different LNG.19
Bibliography .21
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SIST EN ISO 23306:2020
ISO 23306:2020(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 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 28, Petroleum and related products, fuels
and lubricants from natural or synthetic sources, Subcommittee SC 4, Classifications and specifications,
in collaboration with the European Committee for Standardization (CEN) Technical Committee
CEN/TC 408, Natural gas and biomethane for use in transport and biomethane for injection in the natural
gas grid, 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.
iv © ISO 2020 – All rights reserved
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Introduction
Due to numerous economic and environmental factors, the use of liquefied natural gas (LNG) as fuel
for marine applications has increased. The 0,10 % sulfur limit, in the sulfur emission controlled areas
in Europe and the US, which entered into force on 1 January 2015 has been one of the major driving
forces for using LNG as fuel for marine applications. The decision for the 0,50 % global sulfur limit from
1 January 2020 by the International Maritime Organization (IMO) might further increase the interest
in LNG. The International Code of Safety for Ships using Gases or other Low-flashpoint Fuels (IGF Code)
was a response to the need of guidance in this emerging market. Since LNG-fueled vessels are likely
to bunker LNG in different parts of the world, a common specification is needed for ship owners, ship
operators and LNG suppliers. It would help engine manufacturers and ship designers and it is beneficial
for the development of this new alternative marine fuel market.
In 2018, IMO adopted an initial strategy on reduction of greenhouse gas (GHG) emissions from ships.
The strategy includes the objective to peak GHG emissions from international shipping as soon as
possible, whilst pursuing efforts towards decarbonizing the sector as soon as possible in this century.
It also includes the objectives to reduce the CO emissions per transport work and total annual GHG
2
emissions from international shipping by 2050, with an interim target in 2030. Thus, LNG produced
from renewable sources as biomethane that can reduce CO emissions when used as marine fuel is also
2
addressed in this document.
LNG is produced in different locations in the world in liquefaction plants. Large scale production
facilities are often dedicated to specific markets such as natural gas grids and large power plants
that use their own standards. This document takes into consideration this major constraint for any
adaptation to marine applications specificities/requirements.
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SIST EN ISO 23306:2020
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SIST EN ISO 23306:2020
INTERNATIONAL STANDARD ISO 23306:2020(E)
Specification of liquefied natural gas as a fuel for marine
applications
1 Scope
This document specifies the quality requirements for Liquefied Natural Gas (LNG) used as a fuel for
marine applications. It defines the relevant parameters to measure as well as the required values and
the test reference methods for all those parameters.
This document applies to LNG from any source, e.g. gas from conventional reservoirs, shale gas, coalbed
methane, biomethane, synthetic methane. LNG described in this document can come from synthesis
process out of fossil fuels or renewable sources.
This document identifies the required specifications for fuels delivered at the time and place of custody
transfer (at the delivery point).
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 6578, Refrigerated hydrocarbon liquids — Static measurement — Calculation procedure
ISO 6974 (all parts), Natural gas — Determination of composition and associated uncertainty by gas
chromatography
ISO 6976, Natural gas — Calculation of calorific values, density, relative density and Wobbe indices from
composition
ISO 8943, Refrigerated light hydrocarbon fluids — Sampling of liquefied natural gas — Continuous and
intermittent methods
EN 16726, Gas infrastructure — Quality of gas — Group H
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
biomethane
methane rich gas derived from biogas or from gasification of biomass by upgrading with the properties
similar to natural gas
[SOURCE: ISO 14532:2014, 2.1.1.15]
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
3.2
liquefied natural gas
LNG
natural gas that has been liquefied after processing
[SOURCE: ISO 14532:2014, 2.1.1.12, modified — Definition has been shortened, note to entry has been
deleted.]
3.3
methane number
MN
rating indicating the knocking characteristics of a fuel gas
Note 1 to entry: It is comparable to the octane number for petrol. One expression of the methane number is the
volume percentage of methane in a methane-hydrogen mixture, that in a test engine under standard conditions
has the same tendency to knock as the fuel gas to be examined.
[SOURCE: ISO 14532:2014, 2.6.6.1]
3.4
natural gas
complex gaseous mixture of hydrocarbons, primarily methane, but generally includes ethane, propane
and higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide
Note 1 to entry: Natural gas can also contain components or contaminants such as sulfur compounds and/or
other chemical species.
[SOURCE: ISO 14532:2014, 2.1.1.1]
3.5
Wobbe index
calorific value on a volumetric basis at specified reference conditions, divided by the square root of the
relative density at the same specified metering reference conditions
[SOURCE: ISO 14532:2014, 2.6.4.3, modified — Note to entry has been deleted.]
4 General requirements
4.1 The LNG at the delivery point shall conform with the characteristics and limits given in Table 1
when tested in accordance with the specified methods.
The components listed in Table 1 and Table 2 shall be measured to enable the calculation of the physical
properties of the LNG at the delivery point.
4.2 The LNG delivered shall be free from any material at a concentration that causes the LNG to be
unacceptable for use, i.e. material not at a concentration that is harmful to personnel, jeopardizes the
safety of the ship, or adversely affects the performance of the machinery.
4.3 Physicochemical characteristics not requiring measurement are listed in Table 3.
It is not practical to require detailed chemical analysis for each delivery of fuels beyond the
requirements listed in Table 1 or Table 2. Instead, a liquefaction plant, LNG terminal or any other supply
facility, including supply barges and truck deliveries, shall have in place adequate quality assurance
and management of change procedures to ensure that the resultant LNG is in conformance with the
requirements of this document.
Examples of LNG compositions are given in Annex B.
Information on ageing of LNG can be found in Annex D and information on particles can be found in
Annex E.
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
4.4 The reference conditions shall be 288,15 K, 101,325 kPa (see ISO 13443:1996, Clause 3) in the
gaseous phase.
5 Sampling
Samples for quality verification are not mandatory but can be taken at various locations as agreed
among the parties concerned. Samples, if any, can also be taken at multiple moments in time, as LNG
has distinct different ageing characteristics than traditional hydrocarbon maritime fuels (with regards
to ageing reference is made to Annex D). In order to ensure a representative sample, proper sampling
procedures should be followed.
When sampling of LNG for analysis is carried out, it shall be in accordance with the procedures
provided in ISO 8943 or an equivalent national standard agreed between the parties concerned. Where
specific sampling requirements are documented, the relevant parties should agree on the reference
test methods. The LNG collected in liquid state shall be instantly conditioned to gaseous state without
any partial vaporization or loss of molecular components to ensure a representative sample.
There are two methods for sampling LNG as defined in ISO 8943, continuous and intermittent. Both
methods obtain LNG from the LNG cargo/bunker line and then it is gasified in a vaporizer. The
continuous method collects the gasified LNG in a sample holder at a constant flow rate for offline
analysis. The intermittent method collects gasified LNG and directs it to an on-line analyzer at
predetermined intervals. Please refer to ISO 8943 for more details on these methods.
The requirements for sampling LNG for marine applications can vary throughout the industry,
depending on availability and equipment. Load port samples can be used for quality determination if
the sampling equipment is not available and if it is agreed between the parties.
6 Requirements, limit values and related test methods
The components and physicochemical characteristics that shall be measured or calculated using the
related test methods are given in Table 1 and Table 2.
[1]
NOTE Information can be found in ISO 6975 .
Information on MN and Wobbe index can be found in Annex C.
Table 1 — Physicochemical characteristics requiring measurement/calculation with limit values
Characteristic Unit Limit Value Test method
3 a
Net Calorific Value (NCV) MJ/m (s) Min 33,6 ISO 6976
Nitrogen % (mol) Max 1,0 ISO 6974 (all parts)
Annex A (Propane knock
b
Methane Number (MN) no unit Min
index) or EN 16726
a
Calculated for a theoretical mixture of 99 % (mol) methane and 1 % (mol) nitrogen in liquid phase. The
Gross Calorific Value can be calculated from the Net Calorific Value (see ISO 13443:1996).
b
Both the method used for determining the MN and the minimum value shall be agreed between supplier and user.
The fuel supplier shall calculate the actual MN at the delivery point and provide this information to the
user (see Clause 5 for sampling location). This information shall be given as MN or MN .
(PKI) (EN 16726)
For guidance on the MN applicability to a specific application, Original Equipment Manufacturer (OEM)
specifications should be considered.
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Table 2 — Physicochemical characteristics requiring measurement without limit values
Characteristic Unit Test method Value
a 3
Density kg/m ISO 6578 Report
Methane (CH ) % (mol) ISO 6974 (all parts) Report
4
Ethane (C H ) % (mol) ISO 6974 (all parts) Report
2 6
Propane (C H ) % (mol) ISO 6974 (all parts) Report
3 8
n-Butane (C H )
4 10
% (mol) ISO 6974 (all parts) Report
i-Butane
Pentane(C H ) % (mol) ISO 6974 (all parts) Report
5 12
a
Density at temperature of the liquid phase.
7 Main compounds removed by liquefaction process
Natural gas is liquid at around −160 °C under atmospheric pressure and becomes Liquefied Natural
Gas (LNG). To avoid freezing and plugging in the liquefaction plant's cryogenic heat exchangers,
usual impurities or compounds that are present in the natural gas from various sources are removed
upstream from the liquefaction process below their solubility level. Some LNG components (e.g. ethane,
propane, butane and pentane) are possibly removed for commercial reasons or to achieve a targeted
calorific value range.
LNG composition is therefore within more narrow limits compared to natural gas. The compounds
that can be considered as harmful for marine applications are removed or reduced to very low levels
(trace) so that they are no more a concern. They shall comply with 4.2. The main compounds removed
by liquefaction are listed in Table 3 and below for information and reference. The measurement of
these species is not required. However, if the parties concerned agree to measure them, they should be
measured according to the referenced methods listed in Table 3.
The melting and boiling points for a range of compounds, including those possibly present in biomethane,
are available in Table F.1.
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Table 3 — Main compounds removed by liquefaction and not requiring measurement
Solubility limit
in LNG (around Typical value out
Characteristic Unit Test method Remarks
−160 °C, atm. of LNG plant
Pressure)
Hexane and % (mol) ISO 6974 (all n.a. n.a. n.a.
higher parts)
hydrocarbons
3 [5] 3
Total sulfur mg(S)/m ISO 19739 (n.a.) Max 30 mg(S)/m Depends on LNG
(gas) contracts. Actual
[6]
ISO 20729
value very often
much lower.
3 3
Hydrogen sulfide mg/m ISO 19739 n.a. 4,29 mg/m (N) Removed in Acid
Gas Removal Unit
(AGRU) in liquefac-
tion plant for safety
purposes.
3
Mercaptan mg/m ISO 19739 Depends on size n.a. Removed in AGRU or
of molecule in heavy hydrocar-
bon removal unit in
liquefaction plant.
Carbon dioxide % (mol) ISO 6974 (all Around 0,02 % 0,005 % (mol) Removed in AGRU in
parts) (mol) liquefaction plant.
Oxygen % (mol) ISO 6974 (all n.a. n.a. Removed in
parts) liquefaction plant
3 [3] 3
Water mg/m ISO 10101 Below 0,74 mg/ 0,74 mg/m or Removed in
3
m below dehydration unit in
liquefaction plant
3 [2] 3
Mercury µg/m ISO 6978-2 n.a. 0,01 μg/m Removed in
liquefaction plant
NOTE See Annex F for components in low concentration or absent, e.g. siloxanes.
n.a. Not available.
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Annex A
(normative)
Propane knock index: Methane number calculation method
The MN of a gaseous fuel can be calculated from its composition according to several different methods,
all of which can give different results. The methodology described in this Annex shall be employed to
calculate MN .
(PKI)
For components listed in Table 3, the mole fraction can be taken as equal to "0".
®1)
DNV GL developed a MN method (“PKI MN”) that characterizes gases for their knock resistance
based on the combustion properties of the fuel mixtures themselves. The PKI MN method is based on a
[8]
methane-propane scale (PKI, Propane Knock Index) where the knock resistance of gas composition is
compared to the knock resistance of a methane-propane gas mixture under identical engine conditions.
To calculate the PKI values a polynomial, Formula (A.1) is used:
n n m
PKIX=∑αβ+∑ XX (A.1)
nni m i j
i ij*
where
X is the (normalized) mole fraction,
i = CH , C H , C H , i-C H , n-C H , n-C H , i-C H , neo-C H , CO , CO, H and N ;
4 2 6 3 8 4 10 4 10 5 12 5 12 5 12 2 2 2
j = C H , C H , i-C H , n-C H , n-C H , i-C H , neo-C H , CO , CO, H and N ;
2 6 3 8 4 10 4 10 5 12 5 12 5 12 2 2 2
n = 1 to 4;
m = 1, 2;
α and β values are given in Table A.2.
The calculation is valid for PKI values ≤20 (or MN ≥ 53, see below) and the gas composition range in
(PKI)
Table A.1.
Table A.1 — Gas composition range
Species Min, mol % Max, mol %
CH 65 100
4
C H 0 20
2 6
C H 0 20
3 8
i-C H 0 5
4 10
n-C H 0 5
4 10
n-C H 0 2
5 12
i-C H 0 2
5 12
neo-C H 0 2
5 12
C + 0 1,5
6
H 0 20
2
1) DNV GL is a trademark of DNV GL AS. This information is given for the convenience of users of this document
and does not constitute an endorsement by ISO.
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Table A.1 (continued)
Species Min, mol % Max, mol %
CO 0 10
CO 0 20
2
N 0 20
2
H S 0 0,5
2
To account for the presence of C + and H S in the gas mixture scaling factors are derived based on
6 2
®1)
autoignition measurements in a rapid compression machine at DNV GL . These scaling factors are
used in the algorithm to translate the effect of C + and H S on the knock resistance of a gas mixture
6 2
to an equivalent fraction of n-C H . The factors are used to correct the methane and n-pentane mole
5 12
fractions as in Formulae (A.2) and (A.3).
XX=−03, ×X (A.2)
CH44,newCHingasmixtureC6+
XX=+XX+×13, (A.3)
nC51Hn25, ew nC Hi12 ngasmixtureH26SC +
Where X denotes the mole fraction. Here we note that the results of the algorithm are only valid if the
total mole percentages of the gas mixture is 100 %.
Table A.2 — α and β coefficients in Formula (A.1)
Coefficient Value Description
α 569,285 536 016 002 0 CH
CH4 4
2
α −650,854 339 490 7 CH ^2
(CH4) 4
3
α 64,359 575 257 386 2 CH ^3
(CH4) 4
4
α 17,214 959 222 053 6 CH ^4
(CH4) 4
α −645,099 966 662 855 0 C H
C2H6 2 6
2
α 694,229 376 857 102 0 C H ^2
(C2H6) 2 6
3
α −675,381 075 231 165 0 C H ^3
(C2H6) 2 6
4
α 1 474,790 791 373 33 C H ^4
(C2H6) 2 6
α 499,398 492 651 52 C H
C3H8 3 8
2
α −576,665 945 472 394 0 C H ^2
(C3H8) 3 8
3
α 252,193 674 060 28 C H ^3
(C3H8) 3 8
4
α 593,958 975 466 507 0 C H ^4
(C3H8) 3 8
α 934,466 273 223 240 0 N_C
n-C4H10 4
2
α −86,872 357 077 023 8 N_C ^2
(n-C4H10) 4
3
α −20 418,906 767 397 9 N_C ^3
(n-C4H10) 4
4
α 633 286,561 358 521 0 N_C ^4
(n-C4H10) 4
α 735,223 884 113 728 0 I_C
iso-C4H10 4
2
α −3 182,614 393 379 67 I_C ^2
(iso-C4H10) 4
3
α 20 945,186 725 021 9 I_C ^3
(iso-C4H10) 4
4
α 159 067,868 032 595 0 I_C ^4
(iso-C4H10) 4
α 2 571,930 793 605 35 N_C
n-C5H12 5
2
α 10 516,494 109 227 50 N_C ^2
(n-C5H12) 5
3
α −770 539,377 197 693 N_C ^3
(n-C5H12) 5
4
α 28 633 475,586 565 4 N_C ^4
(n-C5H12) 5
α −3 582,967 844 353 79 I_C
iso-C5H12 5
2
α 0 I_C ^2
(iso-C5H12) 5
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SIST EN ISO 23306:2020
ISO 23306:2020(E)
Table A.2 (continued)
Coefficient Value Description
3
α 403 155,950 864 334 I_C ^3
(iso-C5H12) 5
4
α −11 917 333,837 932 9 I_C ^4
(iso-C5H12) 5
α 1 123,396 367 098 65 NEC
neo-C5H12 5
2
α 1 679,728 075 248 10 NEC ^2
(neo-C5H12) 5
3
α −172 182,649 067 176 NEC ^3
(neo-C5H12) 5
4
α 3 467 918,607 466
...
SLOVENSKI STANDARD
oSIST prEN ISO 23306:2020
01-januar-2020
Specifikacija utekočinjenega zemeljskega plina kot goriva za uporabo v pomorstvu
(ISO/DIS 23306:2019)
Specification of liquefied natural gas as a fuel for marine applications (ISO/DIS
23306:2019)
Festlegungen für Flüssigerdgas als Kraftstoff für marine Anwendungen (ISO/DIS
23306:2019)
Spécification du gaz naturel liquéfié comme carburant pour les applications maritimes
(ISO/DIS 23306:2019)
Ta slovenski standard je istoveten z: prEN ISO 23306
ICS:
75.160.30 Plinska goriva Gaseous fuels
oSIST prEN ISO 23306:2020 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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oSIST prEN ISO 23306:2020
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oSIST prEN ISO 23306:2020
DRAFT INTERNATIONAL STANDARD
ISO/DIS 23306
ISO/TC 28/SC 4 Secretariat: AFNOR
Voting begins on: Voting terminates on:
2019-12-03 2020-02-25
Specification of liquefied natural gas as a fuel for marine
applications
Spécification du gaz naturel liquéfié comme carburant pour les applications marines
ICS: 75.160.30
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 23306:2019(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
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(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
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Published in Switzerland
ii © ISO 2019 – All rights reserved
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 General requirements . 2
5 Sampling . 3
6 Requirements, limit values and related test methods . 3
7 Compounds removed by liquefaction process .4
Annex A (normative) Propane Knock Index: Methane Number calculation method .6
Annex B (informative) Examples of LNG composition .12
Annex C (informative) Methane Number (knock resistance) and Wobbe Index (thermal
input through a restriction) .15
Annex D (informative) LNG ageing along the bunkering chain .17
Annex E (informative) Particles .18
Annex F (informative) Melting and boiling points of components and impurities in different
LNG .19
Bibliography .21
© ISO 2019 – All rights reserved iii
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO's adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT) see the following URL: www .iso .org/iso/foreword .html.
The committee responsible for this document is ISO/TC 28, Petroleum and related products, fuels and
lubricants from natural or synthetic sources, SC 4, Classifications and specifications.
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 2019 – All rights reserved
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
Introduction
Due to numerous economic and environmental factors, the use of liquefied natural gas (LNG) as fuel
for marine applications has increased. The 0,10% sulphur limit, in the sulphur emission controlled
st
areas in Europe and the US, which entered into force the 1 of January 2015 has been one of the major
driving forces for using LNG as fuel for marine applications. The decision for the 0,50% global sulphur
limit by the International Maritime Organization (IMO) may further increase the interest in LNG. The
International Code of Safety for Ships using Gases or other Low-flashpoint Fuels (IGF Code), entering
st
into force on the 1 of January 2017 was a response to the need of guidance in this emerging market.
Since LNG-fueled vessels are likely to bunker LNG in different parts of the world, a common specification
is needed for ship owners, ship operators and LNG suppliers. It also helps engine manufacturers and
ship designers and it is beneficial for the development of this new alternative marine fuel market.
In 2018, IMO adopted an initial strategy on reduction of greenhouse gas (GHG) emissions from ships.
The strategy includes the objective to peak GHG emissions from international shipping as soon as
possible, whilst pursuing efforts towards decarbonizing the sector as soon as possible in this century.
It also includes the objectives to reduce the CO emissions per transport work and total annual GHG
2
emissions from international shipping by 2050, with an interim target in 2030.Thus, LNG produced
from renewable sources as biomethane that can reduce CO emissions when used as marine fuel is also
2
addressed in this document.
LNG is produced in different locations in the world in liquefaction plants. Large scale production
facilities are often dedicated to specific markets such as natural gas grids and large power plants
that use their own standards. This document takes into consideration this major constraint for any
adaptation to marine applications specificities/requirements.
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oSIST prEN ISO 23306:2020
DRAFT INTERNATIONAL STANDARD ISO/DIS 23306:2019(E)
Specification of liquefied natural gas as a fuel for marine
applications
1 Scope
This document specifies the quality requirements for Liquefied Natural Gas (LNG) used as a fuel for
marine applications. It defines the relevant parameters to be measured as well as the required values
and the test reference methods for all those parameters.
This document applies to LNG from any source, e.g. gas from conventional reservoirs, shale gas, coalbed
methane, biomethane, synthetic methane. LNG described in this document may come from synthesis
process out of fossil fuels or renewable sources.
This document identifies the required specifications for fuels delivered at the time and place of custody
transfer (at the delivery point).
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 6578, Refrigerated hydrocarbon liquids — Static measurement — Calculation procedure
ISO 6974 (all parts), Natural gas -- Determination of composition and associated uncertainty by gas
chromatography
ISO 6976, Natural gas — Calculation of calorific values, density, relative density and Wobbe indices from
composition
ISO 8943, Refrigerated light hydrocarbon fluids — Sampling of liquefied natural gas — Continuous and
intermittent methods
ISO 13443:1996, Natural gas — Standard reference conditions
EN 16726, Gas infrastructure - Quality of gas - Group H
3 Terms and definitions
For the purposes of this document, the following terms and definitions 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
biomethane
methane rich gas derived from biogas or from gasification of biomass by upgrading with the properties
similar to natural gas
[1]
[SOURCE: ISO 14532:2014, 2.1.1.15]
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
3.2
Liquefied Natural Gas
LNG
natural gas that has been liquefied after processing
[SOURCE: ISO 14532:2014, 2.1.1.12]
3.3
Methane Number
MN
rating indicating the knocking characteristics of a fuel gas
Note 1 to entry: It is comparable to the octane number for petrol. One expression of the methane number is the
volume percentage of methane in a methane-hydrogen mixture, that in a test engine under standard conditions
has the same tendency to knock as the fuel gas to be examined.
[SOURCE: ISO 14532:2014, 2.6.6.1]
3.4
natural gas
complex gaseous mixture of hydrocarbons, primarily methane, but generally includes ethane, propane
and higher hydrocarbons, and some non-combustible gases such as nitrogen and carbon dioxide
Note 1 to entry: Natural gas can also contain components or contaminants such as sulfur compounds and/or
other chemical species.
[SOURCE: ISO 14532:2014, 2.1.1.1]
3.5
Wobbe index
calorific value on a volumetric basis at specified reference conditions, divided by the square root of the
relative density at the same specified metering reference conditions
[SOURCE: ISO 14532:2014, 2.6.4.3]
4 General requirements
4.1 The LNG at the delivery point shall comply with the characteristics and limits given in Table 1 when
tested in accordance with the specified methods.
The components listed in Table 1 and Table 2 shall be measured to enable the calculation of the physical
properties of the LNG at the delivery point.
4.2 The LNG delivered shall be free from any material at a concentration that causes the LNG to be
unacceptable for use in accordance with Clause 1 (i.e. material not at a concentration that is harmful to
personnel, jeopardizes the safety of the ship, or adversely affects the performance of the machinery).
4.3 Physicochemical characteristics not requiring measurement are listed in Table 3.
It is not practical to require detailed chemical analysis for each delivery of fuels beyond the requirements
listed in Table 1 or Table 2. Instead, a liquefaction plant, LNG terminal or any other supply facility,
including supply barges and truck deliveries, should have in place adequate quality assurance and
management of change procedures to ensure that the resultant LNG is compliant with the requirements
of this document.
Examples of LNG compositions are given in Annex B.
Information on ageing of LNG can be found in Annex D and information on particles can be found in
Annex E.
2 © ISO 2019 – All rights reserved
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
5 Sampling
Samples for quality verification, if any, may be taken at various locations as agreed among the parties
concerned. Samples, if any, may also be taken at multiple moments in time, as LNG has distinct different
ageing characteristics than traditional hydrocarbon maritime fuels (with regards to ageing reference
is made to Annex D). In order to ensure a representative sample, it is essential that proper sampling
procedures are followed.
When sampling of LNG for analysis is carried out, it shall be in accordance with the procedures provided
in ISO 8943 or an equivalent national standard. Where specific sampling requirements are documented,
the relevant parties should agree on the reference test methods. It is most imperative to ensure the LNG
collected in liquid state is instantly conditioned to gaseous state without any partial vaporization or
loss of molecular components to ensure a representative sample.
There are two methods of sampling LNG as defined in ISO 8943, continuous and intermittent. Both
methods obtain LNG from the LNG cargo/bunker line and then it is gasified in a vaporizer. The
continuous method collects the gasified LNG in a sample holder at a constant flow rate for offline
analysis. The intermittent method collects gasified LNG and directs it to an on-line analyzer at
predetermined intervals. Please refer to ISO 8943 for more details on these methods.
The requirements for sampling LNG for marine applications can vary throughout the industry
depending on availability and equipment. Load port samples may be used for quality determination if
the sampling equipment is not available and if it is agreed between the parties.
6 Requirements, limit values and related test methods
The components and physicochemical characteristics that shall be measured or calculated and the
related test methods are given in Table 1 and Table 2.
[2]
Note Information can be found in ISO 6975 .
The reference conditions shall comply with ISO 13443:1996, Clause 3, which are 288,15 K, 101,325 kPa.
Information on MN and Wobbe index can be found in Annex C.
Table 1 — Physicochemical characteristics requiring measurement/calculation with limit values
Characteristic Unit Limit Value Test method
3 a
Net Calorific Value (NCV) MJ/m (s) Min 33,6 ISO 6976
b
Nitrogen % (mol) Max 1,0 ISO 6974
Annex A (PKI) or
c
Methane Number (MN) no unit Min
[7]
EN 16726
a
calculated for a theoretical mixture of 99% methane and 1% nitrogen in liquid phase
b
decided to limit the nitrogen concentration and pressure in the boil-off gas
c
both the method used for determining the MN and the minimum value shall be agreed between supplier
and user
The fuel supplier shall calculate the actual MN at the delivery point and provide this information to the
user (see Clause 5 for sampling location). This information shall be given as MN or MN (EN16726).
(PKI)
For guidance on the MN applicability to a specific application, Original Equipment Manufacturer (OEM)
specifications should be considered.
Table 2 — Physicochemical characteristics requiring measurement without limit values
Characteristic Unit Test method Value
a 3
Density kg/m ISO 6578 Report
Methane (CH ) % (mol) ISO 6974 Report
4
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
Table 2 (continued)
Characteristic Unit Test method Value
Ethane (C H ) % (mol) ISO 6974 Report
2 6
Propane (C H ) % (mol) ISO 6974 Report
3 8
n-Butane (C H ) Report
4 10
% (mol) ISO 6974
i-Butane
Pentane(C H ) % (mol) ISO 6974 Report
5 12
density at temperature of the liquid phase
7 Compounds removed by liquefaction process
Natural gas is liquid at around -160°C under atmospheric pressure and becomes Liquefied Natural
Gas (LNG). To avoid freezing and plugging in the liquefaction plant's cryogenic heat exchangers,
usual impurities or compounds that are present in the natural gas from various sources are removed
upstream from the liquefaction process below their solubility level. Some LNG components (e.g. ethane,
propane, butane and pentane) are possibly removed for commercial reasons or to achieve a targeted
calorific value range.
LNG composition is therefore within more narrow limits compared to natural gas. The compounds
which can be considered as harmful for marine applications are removed or reduced to very low levels
(trace) so that they are no more a concern. They shall comply with Clause 4.2. The main compounds
removed by liquefaction are listed in Table 3 and below for information and reference. The measurement
of these species is not required. However, if the parties concerned agree to measure them, they should
be measured according to the referenced methods listed in Table 3.
The reference conditions shall comply with ISO 13443:1996, Clause 3, which are 288,15 K, 101,325 kPa.
The melting and boiling points for a range of compounds, including those possibly present in biomethane,
are available in Annex F, Table F.1.
4 © ISO 2019 – All rights reserved
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Table 3 — Physicochemical characteristics not requiring measurement
Characteristic Unit Test method Solubility limit Typical value out Remarks
in LNG (~-160°C, of LNG plant
atm. Pressure)
Hexane and high- % (mol) ISO 6974 n.a. n.a. n.a.
er hydrocarbons
3 [3] 3
Total sulphur mg(S)/m ISO 19739 Not applicable Max 30 mg(S)/m Depends on LNG
(n.a.) (gas) contracts. Actual
[4]
ISO 20729
value very often
much lower.
3 3
Hydrogen sul- mg/m ISO 19739 4,29mg/m (N) Removed in Acid
phide Gas Removal Unit
(AGRU) in liquefac-
tion plant for safety
purposes.
3
Mercaptan mg/m ISO 19739 Depends on size n.a. Removed in AGRU or
of molecule in heavy hydrocar-
bon removal unit in
liquefaction plant.
Carbon dioxide mol% ISO 6974 Around 0,005mol% Removed in AGRU in
0,02mol% liquefaction plant.
Oxygen mol% ISO 6974 n.a. n.a. Removed in lique-
faction plant
3 [5] 3
Water mg/m ISO 10101 Below 0,74mg/ 0,74mg/m or Removed in de-
m3 below hydration unit in
liquefaction plant
3 [6] 3
Mercury µg/m ISO 6978-2 n.a. 0,01μg/m Removed in lique-
faction plant
Note 1: see Annex F for components in low concentration or absent e.g. siloxanes
Note 2: n.a. means not available
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
Annex A
(normative)
Propane Knock Index: Methane Number calculation method
The MN of a gaseous fuel can be calculated from its composition according to several different
methods, all of which can give different results. For the purpose of compliance with this document, the
methodology described in this Annex shall be employed to calculate MN .
(PKI)
For components listed in Table 3, the mole fraction can be taken as equal to "0".
DNV GL developed a MN method (“PKI MN”) that characterizes gases for their knock resistance based
on the combustion properties of the fuel mixtures themselves. The PKI MN method is based on a
[7]
methane-propane scale (PKI, Propane Knock Index), where the knock resistance of gas composition is
compared to the knock resistance of a methane-propane gas mixture under identical engine conditions.
To calculate the PKI values a polynomial Formula (A.1) is used:
n n m
PKIX=∑αβ+∑ XX (A.1)
nni m i j
i ij*
where
X is the (normalized) mole fraction,
i = CH , C H , C H , i-C H , n-C H , n-C H , i-C H , neo-C H , CO , CO, H and N ;
4 2 6 3 8 4 10 4 10 5 12 5 12 5 12 2 2 2
j = C H , C H , i-C H , n-C H , n-C H , i-C H , neo-C H , CO , CO, H and N ;
2 6 3 8 4 10 4 10 5 12 5 12 5 12 2 2 2
n = 1 to 4 and m =1, 2;
α and β values are given in Table A.2.
The calculation is valid for PKI values ≤ 20 (or MN MN ≥ 53, see below) and the gas composition
(PKI)
range in Table A.1.
Table A.1 — Gas composition range
Species Min, mol % Max, mol %
CH 65 100
4
C H 0 20
2 6
C H 0 20
3 8
i-C H 0 5
4 10
n-C H 0 5
4 10
n-C H 0 2
5 12
i-C H 0 2
5 12
neo-C H 0 2
5 12
C + 0 1,5
6
H 0 20
2
CO 0 10
CO 0 20
2
N 0 20
2
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ISO/DIS 23306:2019(E)
Table A.1 (continued)
Species Min, mol % Max, mol %
H S 0 0,5
2
To account for the presence of C + and H S in the gas mixture scaling factors are derived based on
6 2
autoignition measurements in a rapid compression machine at DNV GL. These scaling factors are
used in the algorithm to translate the effect of C + and H S on the knock resistance of a gas mixture
6 2
to an equivalent fraction of n-C H . The factors are used to correct the methane and n-pentane mole
5 12
fractions as follows:
XX=−03. ×X (A.2)
CH44,newCHingasmixturec6+
XX=+XX+×13. (A.3)
nC51Hn25, ew nC Hi12 ngasmixtureH26SC +
Where X denotes the mole fraction. Here we note that the results of the algorithm are only valid if the
total mole percentages of the gas mixture is 100%.
Table A.2 — α and β coefficients in Formula (A.1)
Coefficient Value Description
α 569,2855360160020 CH
CH4 4
2
α -650,8543394907 CH ^2
(CH4) 4
3
α 64,3595752573862 CH ^3
(CH4) 4
4
α 17,2149592220536 CH ^4
(CH4) 4
α -645,0999666628550 C H
C2H6 2 6
2
α 694,2293768571020 C H ^2
(C2H6) 2 6
3
α -675,3810752311650 C H ^3
(C2H6) 2 6
4
α 1474,79079137333 C H ^4
(C2H6) 2 6
α 499,39849265152 C H
C3H8 3 8
2
α -576,6659454723940 C H ^2
(C3H8) 3 8
3
α 252,19367406028 C H ^3
(C3H8) 3 8
4
α 593,9589754665070 C H ^4
(C3H8) 3 8
α 934,4662732232400 N_C
n-C4H10 4
2
α -86,8723570770238 N_C ^2
(n-C4H10) 4
3
α -20418,9067673979 N_C ^3
(n-C4H10) 4
4
α 633286,5613585210 N_C ^4
(n-C4H10) 4
α 735,2238841137280 I_C
iso-C4H10 4
2
α -3182,61439337967 I_C ^2
(iso-C4H10) 4
3
α 20945,1867250219 I_C ^3
(iso-C4H10) 4
4
α 159067,8680325950 I_C ^4
(iso-C4H10) 4
α 2571,93079360535 N_C
n-C5H12 5
2
α 10516,49410922750 N_C ^2
(n-C5H12) 5
3
α -770539,377197693 N_C ^3
(n-C5H12) 5
4
α 28633475,5865654 N_C ^4
(n-C5H12) 5
α -3582,96784435379 I_C
iso-C5H12 5
2
α 0 I_C ^2
(iso-C5H12) 5
3
α 403155,950864334 I_C ^3
(iso-C5H12) 5
4
α -11917333,8379329 I_C ^4
(iso-C5H12) 5
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ISO/DIS 23306:2019(E)
Table A.2 (continued)
Coefficient Value Description
α 1123,39636709865 NEC
neo-C5H12 5
2
α 1679,72807524810 NEC ^2
(neo-C5H12) 5
3
α -172182,649067176 NEC ^3
(neo-C5H12) 5
4
α 3467918,607466990 NEC ^4
(neo-C5H12) 5
α -469,428097827742 N
N2 2
2
α 352,688107288763 N ^2
(N2) 2
3
α -220,491687402358 N ^3
(N2) 2
4
α 1419,680053962420 N ^4
(N2) 2
α -953,460328339263 CO
CO2 2
2
α 1148,487258682280 CO ^2
(CO2) 2
3
α -601,339855375907 CO ^3
(CO2) 2
4
α 448,125565457084 CO ^4
(CO2) 2
α -5813,75996390021 CO
CO
2
α 5511,72102582867 CO^2
(CO)
3
α 1647,04306584326 CO^3
(CO)
4
α -3471,24152555425 CO^4
(CO)
α -906,859878136883 H
H2 2
2
α 1059,74781014028 H ^2
(H2) 2
3
α -1302,86158149863 H ^3
(H2) 2
4
α 3639,85949304520 H ^4
(H2) 2
β 201,788909592169 CH *C H
CH4×C2H6 4 2 6
β -865,856657223225 CH *C H
CH4 •C3H8 4 3 8
β -1210,2275419324 CH *N_C
CH4 •n-C4H10 4 4
2
β 1331,555523696450 (CH *N_C )^2
(CH4 •n-C4H10) 4 4
β -1023,2781474703 CH *I_C
CH4 •iso-C4H10 4 4
2
β 1550,09518461258 (CH4*I_C4)^2
(CH4 × iso-C4H10)
β -2811,67740432523 CH4*N_C5
CH4 × n-C5H12
β 3363,98150506356 CH4*I_C5
CH4 × iso-C5H12
β -1534,52567488723 CH4*NEC5
CH4 × neo-C5H12
β -1,05397332930609 CH4*N2
CH4 × N2
β 473,57476410971 CH4*CO2
CH4 × CO2
2
β -308,25901022921 (CH4*CO2)^2
(CH4 × CO2)
β 5356,4335705495 CH4*CO
CH4 × CO
β 118,685621913274 CH4*H2
CH4 × H2
2
β 252,885168496247 CH4*(H2^2)
CH4 × (H2)
2
β 325,305174695724 (CH4^2)*H2
(CH4) × H2
β 0 C2H6*C3H8
C2H6 × C3H8
β -437,695363730406 C2H6*N_C4
C2H6 × n-C4H10
β -109,983789902769 C2H6*I_C4
C2H6 × iso-C4H10
β -1870,34746500563 C2H6*N_C5
C2H6 × n-C5H12
β 3909,50906076245 C2H6*I_C5
C2H6 × iso-C5H12
β -886,578525827322 C2H6*NEC5
C2H6 × neo-C5H12
β 968,887620927515 C2H6*N2
C2H6 × N2
2
β 267,47276619196 (C2H6^2)*N2
(C2H6) × N2
8 © ISO 2019 – All rights reserved
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oSIST prEN ISO 23306:2020
ISO/DIS 23306:2019(E)
Table A.2 (continued)
Coefficient Value Description
2
β 337,464863958288 C2H6*(N2^2)
C2H6 × (N2)
β 1431,95011699315 C2H6*CO2
C2H6 × CO2
β 6463,14444295627 C2H6*CO
C2H6 × CO
β 1865,09090384357 C2H6*H2
C2H6 × H2
β -118,490180710956 C3H8*N_C4
C3H8 × n-C4H10
β 0 C3H8*I_C4
C3H8 × iso-C4H10
β -1734,80568239427 C3H8*N_C5
C3H8 × n-C5H12
2
β 127551,642193201 C3H8*(N_C5^2)
C3H8 × (n-C5H12)
2
β 11318,4183950722 (C3H8^2)*N_C5
(C3H8) × n-C5H12
β 3318,96820819338 C3H8*I_C5
C3H8 × iso-C5H12
β 0 C3H8*NEC5
C3H8 × neo-C5H12
β 13,345337812469 C3H8*N2
C3H8 × N2
β 292,275289330565 C3H8*CO2
C3H8 × CO2
β 5403,50260794829 C3H8*CO
C3H8 × CO
2
β 2333,82346342921 (C3H8^2)*CO
(C3H8) × CO
β 957,887281487301 C3H8*H2
C3H8 × H2
β 3500,70282852274 N_C4*I_C4
n-C4H10 × iso-C4H10
β -4737,32849494999 N_C4*N_C5
n-C4H10 × n-C5H12
2
β 525591,310711326 NC4*(NC5^2)
n-C4H10 × (n-C5H12)
2
β 297556,039242685 (NC4^2)*NC5
(n-C4H10) × n-C5H12
β 6095,05998875087 N_C4*I_C5
n-C4H10 × iso-C5H12
β -953,002183779388 N_C4*NEC5
n-C4H10 × neo-C5H12
β 0 N_C4*N2
n-C4H10 × N2
β -103,571484346062 N_C4*CO2
n-C4H10 × CO2
β 5869,19050652774 N_C4*CO
n-C4H10 × CO
β 1267,61953483589 N_C4*H2
n-C4H10 × H2
β 5056,60309163761 I_C4*N_C5
iso-C4H10 × n-C5H12
β 6619,27877637044 I_C4*I_C5
iso-C4H10 × iso-C5H12
β -1363,96101644841 I_C4*NEC5
iso-C4H10 × neo-C5H12
β 14,8038957999724 I_C4*N2
iso-C4H10 × N2
β 211,752602673394 I_C4*CO2
iso-C4H10 × CO2
β 5786,32525717488 I_C4*CO
iso-C4H10 × CO
β 1458,46072043154 I_C4*H2
iso-C4H10 × H2
β 12268,283772748 N_C5*I_C5
n-C5H12 × iso-C5H12
β 0 N_C5*NEC5
n-C5H12 × neo-C5H12
β -1573,68893770625 N_C5*N2
n-C5H12 × N2
β -898,466856535774 N_C5*CO2
n-C5H12 × CO2
2
β -42401,4111391824 (N_C5^2)*CO2
(n-C5H12) × CO2
β 3985,11042051103 N_C5*CO
n-C5H12 × CO
2
β 48265,3191033737 (N_C5^2)*CO
(n-C5H12) × CO
β -1112,44352770
...
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