1、BRITISH STANDARDBS EN ISO 6975:2005Incorporating Amendment No. 1 to BS 3156-11.1.2:1997 (renumbers BS as BS EN ISO 6975:2005)Natural gas Extended analysis Gas chromatographic methodThe European Standard EN ISO 6975:2005 has the status of a British StandardICS 75.060g49g50g3g38g50g51g60g44g49g42g3g58
2、g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 6975:2005This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, wa
3、s published under the authority of the Standards Board and comes into effect on 15 August 1997 BSI 17 February 2006ISBN 0 580 28037 3National forewordThis British Standard is the official English language version of EN ISO 6975:2005. It is identical with ISO 6975:1997.The UK participation in its pre
4、paration was entrusted to Technical Committee PTI/15, Natural gas and gas analysis, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep UK interests i
5、nformed; monitor related international and European developments and promulgate them in the UK.A list of organizations represented on this committee can be obtained on request to its secretary.Cross-referencesThe British Standards which implement international or European publications referred to in
6、 this document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online.This publication does not purport to include all the necessary provisions of a
7、contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, pages i and ii, the EN ISO title page, the EN ISO foreword page, the
8、 ISO title page, pages ii and iii, a blank page, pages 1 to 21 and a back cover.The BSI copyright notice displayed in this document indicates when the document was last issued.Amendments issued since publicationAmd. No. Date Comments16104 February 2006 Renumbers BS 3156-11.1.2:1997 as BS EN ISO 6975
9、:2005 BSI 17 February 2006 iContentsPageNational foreword Inside front coverISO foreword iiiText of ISO6975 1BS EN ISO 6975:2005ii blankEUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN ISO 6975May 2005ICS 75.060English versionNatural gas Extended analysis Gas-chromatographic method(ISO 6975:1997)Ga
10、z naturel Analyse tendue Mthode parchromatographie en phase gazeuse (ISO 6975:1997)Erdgas Erweiterte Analyse GaschromatographischesVerfahren (ISO 6975:1997)This European Standard was approved by CEN on 17 April 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stip
11、ulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exis
12、ts in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies
13、 of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STAN
14、DARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN ISO 6975:2005: EForeword The text of ISO 6975:1997 has
15、 been prepared by Technical Committee ISO/TC 193, Natural gas, of the International Organization for Standardization (ISO) and has been taken over as EN ISO 6975:2005 by CMC. This European Standard shall be given the status of a national standard, either by publication of an identical text or by end
16、orsement, at the latest by November 2005, and conflicting national standards shall be withdrawn at the latest by November 2005. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, B
17、elgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 697
18、5:1997 has been approved by CEN as EN ISO 6975:2005 without any modifications. EN ISO 6975:2005EN ISO 6975:2005ii ContentsPageForeword iiiIntroduction 11 Scope 12 Normative references 23 Definitions 34 Principle 45 Analysis and analytical requirements 56 Procedures 77 Calibration and control charts
19、78 Calculations 119 Precision 1310 Test report 13Annex A (informative) Determination of the responsecurves for the main components in a sample 14Annex B (informative) Further details onthe matrices used in Annex A 19Annex C (informative) List of retention indices 20Annex D (informative) Bibliography
20、 21Figure 1 Resolution of two adjacent peaks 4Figure 2 Example of a control chart for nitrogen 9Figure 3 Example of a control chart for carbon dioxide 10Figure 4 Example of a control chart for ethane 11Table 1 Tolerance between concentrations ofcomponents in the WRM and sample 6Table A.1 F-table 18D
21、escriptors: Natural gas, gas analysis, determination of content, hydrocarbons, chromatographic analysis, reference sample.EN ISO 6975:2005 BSI 17 February 2006 BSI 17 February 2006 iii ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bo
22、dies (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 organizatio
23、ns, 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.Draft International Standards adopted by the technical committees are circulate
24、d to the member bodies for voting. Publication as an International Standard requires approval by at least75%of the member bodies casting a vote.International Standard ISO6975 was prepared by Technical CommitteeISO/TC193, Natural gas, Subcommittee SC1, Analysis of natural gas.This second edition canc
25、els and replaces the first edition (ISO6975:1986), which has been technically revised.Annex A to Annex D of this International Standard are for information only.EN ISO 6975:2005 blankiv BSI 17 February 2006 1 IntroductionThis International Standard describes the specifications that an accurate metho
26、d for the complete and extended analysis of natural gas shall fulfil.The analytical methods involve injection of natural gas on to packed or open tubular (capillary) columns inone or more gas chromatographs. The components coming off the columns are detected bythermal-conductivity detector (TCD) or
27、flame ionization detector (FID).Compared to other analytical methods, the extended gas-chromatographic analysis supplies considerable knowledge of the individual components in the natural-gas mixture. This allows quantitative measurement of particular components in the C6+ fraction and calculation o
28、f physical properties. Although the higher hydrocarbons influence physical properties such as calorific values and density by less than0,3% and0,004%, respectively, knowledge of them is required for evaluation of the pseudo-values for the C6+ fraction.In addition, vapour phase equilibrium calculatio
29、ns often require detailed composition data, especially of hydrocarbons with carbon numbers higher than6.The simultaneous determination of benzene and other aromatics is needed for gas consumers using natural gas as a chemical feedstock since these components can interfere in some processes.1 ScopeTh
30、is International Standard describes the specifications for the quantitative analysis of the following components of natural gas:heliumhydrogenargonoxygennitrogencarbon dioxidesaturated hydrocarbons from C1 to C5hydrocarbon fractions from C6 upwardsaromatic compounds as benzene and tolueneThe gas-chr
31、omatographic methods determine the components in the following ranges: This method is not intended for the determination of oxygen compounds (water vapour, methanol, glycols) or sulfur compounds.oxygen: 0,001% (n/n) to 0,5% (n/n)helium: 0,001% (n/n) to 0,5% (n/n)hydrogen: 0,001% (n/n) to 0,5% (n/n)a
32、rgon: 0,001% (n/n) to 0,5% (n/n)nitrogen: 0,001% (n/n) to 40% (n/n)carbon dioxide: 0,001% (n/n) to 40% (n/n)methane: 50% (n/n) to 100% (n/n)ethane: 0,02% (n/n) to 15% (n/n)propane: 0,001% (n/n) to 5% (n/n)higher hydrocarbons: The method can measure hydrocarbon components from106 (n/n) up to their ma
33、ximum concentration, which is compatible with the requirement that the gas is free from hydrocarbon condensate at any pressure in the range1 102 kPa to7 103 kPa.EN ISO 6975:2005 2 BSI 17 February 2006It is not possible to make unambiguous identifications of hydrocarbons above C6. Even where “spiking
34、” a gas mixture with known components shows where they elute, it cannot be stated with certainty that such a component is the only one with that retention time. Unidentified components are classified according to the carbon number which the analysis indicates to be appropriate. While this is a neces
35、sary simplification, it does allow a reasonable quantitative value to be obtained.This method is intended for use in situations where the hexanes plus compositional breakdown and/or the complete analysis is desired.The method is not intended for dense phase gases whose pressure exceeds the cricondeb
36、ar (critical condensation pressure), or for gas samples containing any measurable hydrocarbon condensate, liquid water or process fluid such as methanol or glycols (see ISO6570-1 and ISO10715).Gases which have been treated for transmission are unlikely to contain detectable levels of hydrocarbons ab
37、ove C12. Samples taken from nearer the well head, before the gas has reached gas treatment plants, may contain hydrocarbons to C16 or above.2 Normative referencesThe following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At
38、 the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and I
39、SO maintain registers of currently valid International Standards.ISO5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part1: General principles and definitions. ISO6142:1981, Gas analysis Preparation of calibration gas mixtures Weighing methods. ISO6143:1981, Gas anal
40、ysis Determination of composition of calibration gas mixtures Comparison methods. ISO6326-1:1989, Natural gas Determination of sulfur compounds Part1: General introduction. ISO6326-2:1981, Gas analysis Determination of sulfur compounds in natural gas Part2: Gas chromatographic method using an electr
41、ochemical detector for the determination of odoriferous sulfur compounds. ISO6326-3:1989, Natural gas Determination of sulfur compounds Part3: Determination of hydrogen sulfide, mercaptan sulfur and carbonyl sulfide sulfur by potentiometry. ISO6326-4:1994, Natural gas Determination of sulfur compoun
42、ds Part4: Gas chromatographic method using a flame photometric detector for the determination of hydrogen sulfide, carbonyl sulfide and sulfur-containing odorants. ISO6326-5:1989, Natural gas Determination of sulfur compounds Part5: Lingener combustion method. ISO6570-1:1983, Natural gas Determinati
43、on of potential hydrocarbon liquid content Part1:Principles and general requirements. ISO6974-1:, Natural gas Determination of composition with defined uncertainty by gas chromatography Part1: Guidelines for tailored analysis1). ISO6974-2:, Natural gas Determination of composition with defined uncer
44、tainty by gas chromatography Part2: Measuring system characteristics and statistics for data treatment1). ISO6974-3:, Natural gas Determination of composition with defined uncertainty by gas chromatography Part3: Determination of hydrogen, helium, inert gases and hydrocarbons up to C81). ISO6974-4:,
45、 Natural gas Determination of composition with defined uncertainty by gas chromatography Part4: Determination of nitrogen, carbon dioxide and hydrocarbons (C1 up to C5 andC6+) for a laboratory and on-line measuring system1). ISO6974-5:, Natural gas Determination of composition with defined uncertain
46、ty by gas chromatography Part5: Determination of nitrogen, carbon dioxide and hydrocarbons (C1 up to C5 andC6+) for a laboratory and on-fine process application1). 1) To be published. (Revision, in parts, of ISO6974:1984)EN ISO 6975:2005 BSI 17 February 2006 3 ISO10715:1997, Natural gas Sampling gui
47、delines. ISO14111:1997, Natural gas Guidelines for traceability in analysis. 3 DefinitionsFor the purposes of this International Standard, the following definitions apply.3.1 resolutiongas-chromatographic resolution is a characteristic of the separation of two adjacent peaks and is measured as twice the distance between the maxima of the named peaks divided by the sum of the intercepts on the baseline made by tangents drawn to the peaks at half their height (see Figure 1). The resolution RAB may be expressed by the following equation:3.2 main
