1、December 2016 English price group 23No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 75.060!%j“2599271www.din.deDIN
2、EN ISO 6976Natural gas Calculation of calorific values, density, relative density and Wobbe indices from composition (ISO 6976:2016);English version EN ISO 6976:2016,English translation of DIN EN ISO 6976:2016-12Erdgas Berechnung von Brenn und Heizwert, Dichte, relativer Dichte und Wobbeindex aus de
3、r Zusammensetzung (ISO 6976:2016);Englische Fassung EN ISO 6976:2016,Englische bersetzung von DIN EN ISO 6976:2016-12Gaz naturel Calcul des pouvoirs calorifiques, de la masse volumique, de la densit relative et des indices de Wobbe partir de la composition (ISO 6976:2016);Version anglaise EN ISO 697
4、6:2016,Traduction anglaise de DIN EN ISO 6976:2016-12SupersedesDIN EN ISO 6976:200509www.beuth.deDocument comprises 67 pagesDTranslation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.01.17 DIN EN ISO 6976:2016-12 2 A comma is used as the decim
5、al marker. National foreword This document (EN ISO 6976:2016) has been prepared by Technical Committee ISO/TC 193 “Natural gas”, Subcommittee SC 1 “Analysis of natural gas” (Secretariat: NEN, Netherlands) in collaboration with Technical Committee CEN/TC 238 “Test gases, test pressures, appliance cat
6、egories and gas appliance types” (Secretariat: AFNOR, France). The responsible German body involved in its preparation was DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working Committee NA 062-05-73 AA Gasanalyse und Gasbeschaffenheit. In addition to the legal unit
7、s of measurement, this standard also uses the units “F” (degrees Fahrenheit) and “psi” (pound per square inch). It is important to note that according to the German law on units in metrology, the use of these units is not permitted in official or business communications within Germany. Conversion No
8、n-SI unit SI unit Conversion F C C = 59 (F 32) psi Pa 1 psi = 6 894,757 PaThe DIN Standards corresponding to the International Standards referred to in this document are as follows: ISO 6974-1 DIN EN ISO 6974-1 ISO 6974-2 DIN EN ISO 6974-2 ISO 14912 DIN EN ISO 14912 ISO 80000-1 DIN EN ISO 80000-1 Am
9、endments This standard differs from DIN EN ISO 6976:2005-9 as follows: a) the standard has been technically revised; b) normative references have been included; c) terms and definitions have been updated; d) the former Annex A on symbols and units has been incorporated in the normative text. Previou
10、s editions DIN EN ISO 6976: 2005-09 DIN EN ISO 6976:2016-12 3 National Annex NA (informative) Bibliography DIN EN ISO 6974-1, Natural gas Determination of composition and associated uncertainty by gas chromatography Part 1: General guidelines and calculation of composition DIN EN ISO 6974-2, Natural
11、 gas Determination of composition and associated uncertainty by gas chromatography Part 2: Uncertainty calculations DIN EN ISO 14912, Gas analysis Conversion of gas mixture composition data DIN EN ISO 80000-1, Quantities and units Part 1: General DIN EN ISO 6976:2016-12 4 This page is intentionally
12、blank EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 6976 August 2016 ICS 75.060 Supersedes EN ISO 6976:2005English Version Natural gas - Calculation of calorific values, density, relative density and Wobbe indices from composition(ISO 6976:2016) Gaz naturel - Calcul des pouvoirs calorifiq
13、ues, de la masse volumique, de la densit relative et des indices de Wobbe partir de la composition (ISO 6976:2016)Erdgas - Berechnung von Brenn- und Heizwert, Dichte, relativer Dichte und Wobbeindex aus der Zusammensetzung (ISO 6976:2016) This European Standard was approved by CEN on 24 August 2016.
14、 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
15、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-CENELE
16、C 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy,
17、 Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue
18、Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6976:2016 EEuropean foreword .4Introduction .61 Scope . 72 Normative references 83 Terms and definitions . 84 Symbols and units 114.1 Quantities .
19、114.2 Subscripts . 124.3 Superscript 125 Principles 126 Behaviour of ideal and real gases 136.1 Enthalpy of combustion . 136.2 Calculation of compression factor . 147 Calculation of calorific value on a molar basis . 147.1 Gross calorific value . 147.2 Net calorific value 158 Calculation of calorifi
20、c value on a mass basis . 158.1 Gross calorific value . 158.2 Net calorific value 169 Calculation of calorific value on a volume basis .169.1 Ideal-gas gross calorific value . 169.2 Ideal-gas net calorific value 169.3 Real-gas gross calorific value . 179.4 Real-gas net calorific value 1710 Calculati
21、on of associated properties 1710.1 Ideal-gas relative density 1710.2 Ideal-gas density . 1810.3 Ideal-gas gross Wobbe index . 1810.4 Ideal-gas net Wobbe index . 1810.5 Real-gas relative density 1910.6 Real-gas density 1910.7 Real-gas gross Wobbe index . 1910.8 Real-gas net Wobbe index 2011 Uncertain
22、ty of calculation .2011.1 Principles 2011.2 Formulae for the analytical method 2111.3 Inputs for the analytical method 2111.3.1 Composition and compositional uncertainties .2111.3.2 Non-compositional inputs 2211.4 Expanded uncertainty . 2311.5 Expression of results . 2311.5.1 General. 2311.5.2 Analy
23、tical method 2311.5.3 Generic method 2311.5.4 Contingency method 2311.6 Application of uncertainty . 2412 Tables of data 25Contents Page2DIN EN ISO 6976:2016-12 EN ISO 6976:2016 (E)Foreword .5Annex B (normative) Formulae for uncertainty calculations 33Annex C (informative) Conversion factors .38Anne
24、x D (informative) Example calculations .40Bibliography .633DIN EN ISO 6976:2016-12 EN ISO 6976:2016 (E)Annex A (normative) Values of auxiliary constants .31European foreword This document (EN ISO 6976:2016) has been prepared by Technical Committee ISO/TC 193 “Natural gas” in collaboration with Techn
25、ical Committee CEN/TC 278 “Test gases, test pressures, appliance categories and gas appliance types” 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 Febr
26、uary 2017, and conflicting national standards shall be withdrawn at the latest by February 2017. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held responsible for identifying any or all such pate
27、nt rights. This document supersedes EN ISO 6976:2005. 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, Finla
28、nd, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of IS
29、O 6976:2016 has been approved by CEN as EN ISO 6976:2016 without any modification. 4DIN EN ISO 6976:2016-12 EN ISO 6976:2016 (E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internati
30、onal 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 IS
31、O, 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, Par
32、t 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 e
33、lements 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 rece
34、ived (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 ISOs adh
35、erence 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 193, Natural gas, Subcommittee SC 1, Analysis of natural gas.This third edition cancels and repl
36、aces the second edition (ISO 6976:1995), which has been technically revised.5DIN EN ISO 6976:2016-12 EN ISO 6976:2016 (E)IntroductionBoth international and intra-national custody transfer of natural gas usually require precise determination of both the quantity and the quality of the gas to be trade
37、d. This document specifies methods for the calculation of key properties that describe gas quality, namely gross and net calorific value, density, relative density, and gross and net Wobbe index. The methods provide the means of calculating these properties and their uncertainties for any natural ga
38、s, natural gas substitute or similar combustible gaseous fuel of known composition at commonly used reference conditions.Values of the various properties calculated in accordance with this document will, in general, differ only by very small amounts from those calculated using the second (1995) edit
39、ion of this document. In this context, it is recognized that:a) adoption of the revisions detailed in this document will not be without cost, since instrumental software will need updating;b) recorded energy content and hence billed energy will, in consequence of these revisions, change by small amo
40、unts;c) unintended impacts could occur if the revisions are implemented uncritically; for instance, if the revisions are implemented at input points to a pipeline system but not at exit points, then a costly accountancy imbalance may result;d) commercial, contractual, regulatory and legislative obli
41、gations will need to be taken into account.For these reasons, and depending upon the users application, it may be appropriate to undertake an impact assessment in order to determine an agreed timing and procedure for implementation of the provisions of this document.6DIN EN ISO 6976:2016-12 EN ISO 6
42、976:2016 (E)1 ScopeThis document specifies methods for the calculation of gross calorific value, net calorific value, density, relative density, gross Wobbe index and net Wobbe index of natural gases, natural gas substitutes and other combustible gaseous fuels, when the composition of the gas by mol
43、e fraction is known. The methods specified provide the means of calculating the properties of the gas mixture at commonly used reference conditions.Mole fractions by definition sum to unity. Guidance on the achievement of this requirement by chromatographic analysis is available in ISO 6974-1 and IS
44、O 6974-2.The methods of calculation require values for various physical properties of the pure components; these values, together with associated uncertainties, are provided in tables and their sources are identified.Methods are given for estimating the standard uncertainties of calculated propertie
45、s.The methods of calculation of the values of properties on either a molar, mass or volume basis are applicable to any natural gas, natural gas substitute or other combustible fuel that is normally gaseous, except that for properties on the volume basis the method is restricted to mixtures for which
46、 the compression factor at reference conditions is greater than 0,9.Example calculations are given in Annex D for the recommended methods of calculation.NOTE 1 The qualifiers “superior”, “higher”, “upper” and “total” are, for the purposes of this document, synonymous with “gross”; likewise, “inferio
47、r” and “lower” are synonymous with “net”. The term “heating value” is synonymous with “calorific value”; “mass density” and “specific density” are synonymous with “density”; “specific gravity” is synonymous with “relative density”; “Wobbe number” is synonymous with “Wobbe index”; “compressibility fa
48、ctor” is synonymous with “compression factor”. The dimensionless quantity molecular weight is numerically equal to the molar mass in kgkmol1.NOTE 2 There are no explicit limits of composition to which the methods described in this document are applicable. However, the restriction of volume-basis cal
49、culations to mixtures with a compression factor greater than 0,9 at reference conditions sets implicit limits on composition.NOTE 3 Because the mole fraction of any water present is not normally available from chromatographic analysis, it is common practice to calculate the physical properties on a dry gas basis and to allow for the effects of water vapour in a separate procedure. However, if the mole fraction of water vapour is known then the
