1、BRITISH STANDARDBS EN ISO 6974-6:2008Natural gas Determination of composition with defined uncertainty by gas chromatography Part 6: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and C1to C8hydrocarbons using three capillary columnsICS 75.060g49g50g3g38g50g51g60g44g49g42g3g58g4
2、4g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN ISO 6974-6:2008This British Standard, having been prepared under the direction of the Materials and Chemicals Sector Policy and St
3、rategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 6 November 2002 BSI 2009ISBN 978 0 580 54803 1National forewordThis British Standard is the UK implementation of EN ISO 6974-6:2008. It is identical with ISO 6974-6:2002. It supersedes BS ISO 6974-6
4、:2002The UK participation in its preparation was entrusted to Technical Committee PTI/15, Natural gas and gas analysis.which is withdrawn.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary p
5、rovisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity fromlegal obligations.Amendments issued since publicationDateBS EN ISO 6974-6:2008This corrigendum renumbers BS ISO 6974-6:2002 as 30 April 2009CommentsEUROPEAN STAND
6、ARDNORME EUROPENNEEUROPISCHE NORMEN ISO 6974-6June 2005ICS 75.060English versionNatural gas - Determination of composition with defineduncertainty by gas chromatography - Part 6: Determination ofhydrogen, helium, oxygen, nitrogen, carbon dioxide and C1 toC8 hydrocarbons using three capillary columns
7、 (ISO 6974-6:2002)Gaz naturel - Dtermination de la composition avec uneincertitude dfinie par chromatographie en phase gazeuse -Partie 6: Dtermination de lhydrogne, de lhlium, deloxygne, de lazote, du dioxyde de carbone et deshydrocarbures C1 C8 en utilisant trois colonnescapillaires (ISO 6974-6:200
8、2)Erdgas - Bestimmung der Zusammensetzung mitdefinierter Unsicherheit durch Gaschromatographie - Teil 6:Bestimmung des Wasserstoffs, Heliums, Sauerstoffs,Stickstoffs, Kohlenstoffdioxids und der KohlenwasserstoffeC1 bis C8 mit drei Kapillarsulen (ISO 6974-6:2002)This European Standard was approved by
9、 CEN on 19 May 2005.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate 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 ma
10、y be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists 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 Centr
11、al Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland
12、, Portugal, Slovakia,Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT 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 reser
13、vedworldwide for CEN national Members.Ref. No. EN ISO 6974-6:2005: E2 Foreword The text of ISO 6974-6:2002 has 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 6974-6:2005 by CMC. This European
14、 Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2005, and conflicting national standards shall be withdrawn at the latest by December 2005. According to the CEN/CENELEC Internal Regulations, the natio
15、nal standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Por
16、tugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. Endorsement notice The text of ISO 6974-6:2002 has been approved by CEN as EN ISO 6974-6:2005 without any modifications. iiiContents Foreword iv Introduction. v 1 Scope 1 2 Normative references 1 3 Principle . 3 3.1 Analysis o
17、f natural gas samples . 3 3.2 Analysis of natural gas substitutes. 3 4 Materials. 3 5 Apparatus. 4 6 Procedure. 9 6.1 Operating conditions 9 6.2 Performance requirements. 11 6.3 Determination 11 7 Calculation . 14 8 Precision 14 9 Test report 14 Annex A (informative) Typical precision values 15 Bibl
18、iography 16 iv 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 subjec
19、t 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)
20、 on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committee
21、s are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this part of ISO 6974 may be the subject of patent rights. ISO shall n
22、ot be held responsible for identifying any or all such patent rights. ISO 6974-6 was prepared by Technical Committee ISO/TC 193, Natural gas, Subcommittee SC 1, Analysis of natural gas. This first edition of ISO 6974-6, together with ISO 6974-1, ISO 6974-2, ISO 6974-3, ISO 6974-4 and ISO 6974-5, can
23、cels and replaces ISO 6974:1984 which specified only one method. ISO 6974 consists of the following parts, under the general title Natural gas Determination of composition with defined uncertainty by gas chromatography: Part 1: Guidelines for tailored analysis Part 2: Measuring-system characteristic
24、s and statistics for processing of data Part 3: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and hydrocarbons up to C8using two packed columns Part 4: Determination of nitrogen, carbon dioxide and C1to C5and C6+hydrocarbons for a laboratory and on-line measuring system using t
25、wo columns Part 5: Determination of nitrogen, carbon dioxide and C1to C5and C6+hydrocarbons for a laboratory and on-line process application using three columns Part 6: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and C1to C8hydrocarbons using three capillary columns Annex A o
26、f this part of ISO 6974 is for information only. vIntroduction This part of ISO 6974 describes a precise and accurate method for the analysis of natural gas, which permits the determination of the composition of natural gas. The compositional data obtained are used for the calculation of calorific v
27、alue, relative density and Wobbe index. This method requires the use of three columns which are put in two gas chromatographs. Due to the high separation power of the capillary columns used, components, generally not present in natural gas but in some natural gas substitutes, can also be detected us
28、ing this method. For the analysis of natural gas substitutes, a methanizer is used in addition. This part of ISO 6974 provides one of the methods that may be used for determining the composition of natural gas in accordance with parts 1 and 2 of ISO 6974. 1Natural gas Determination of composition wi
29、th defined uncertainty by gas chromatography Part 6: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and C1to C8hydrocarbons using three capillary columns 1 Scope This part of ISO 6974 describes a gas chromatographic method for the quantitative determination of the content of hyd
30、rogen, helium, oxygen, nitrogen, carbon dioxide and C1to C8hydrocarbons in natural gas samples using three capillary columns. It is applicable to the analysis of gases containing constituents within the mole fraction ranges given in Table 1 and is commonly used for laboratory applications. These ran
31、ges do not represent the limits of detection, but the limits within which the stated precision of the method applies. Although one or more components in a sample may not be present at detectable levels, the method can still be applicable. This part of ISO 6974 is only applicable if used in conjuncti
32、on with parts 1 and 2 of ISO 6974. This method can also be applicable to the analysis of natural gas substitutes. NOTE Additional information on the applicability of this method to the determination of natural gas substitutes is also given where relevant. 2 Normative references The following normati
33、ve documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 6974. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 6974 are encouraged
34、 to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of currently valid International Standards. ISO 6142, G
35、as analysis Preparation of calibration gas mixtures Gravimetric method ISO 6143, Gas analysis Comparison methods for determining and checking the composition of calibration gas mixtures ISO 6974-1:2000, Natural gas Determination of composition with defined uncertainty by gas chromatography Part 1: G
36、uidelines for tailored analysis ISO 6974-2, Natural gas Determination of composition with defined uncertainty by gas chromatography Part 2: Measuring-system characteristics and statistics for processing of data ISO 7504, Gas analysis Vocabulary 2 Table 1 Application ranges Component Formula Mole fra
37、ction % Helium He 0,002 to 0,5 Hydrogen H20,001 to 0,5 Oxygen O20,007 to 5 Nitrogen N20,007 to 40 Methane CH440 to 100 Carbon monoxide aCO 0,001 to 1 Carbon dioxide CO20,001 to 10 Ethyne (Acetylene) aC2H20,001 to 0,5 Ethene a2H40,001 to 0,5 Ethane C2H60,002 to 15 Propene a b C3H60,001 to 0,5 Propane
38、 b3H80,001 to 5 i-Butane C4H100,000 1 to 1 n-Butane C4H100,000 1 to 1 2,2-Dimethylpropane (Neopentane) C5H120,000 1 to 0,5 2-Methylbutane (i-Pentane) C5H120,000 1 to 0,5 n-Pentane C5H120,000 1 to 0,5 Cyclopentane C5H100,000 1 to 0,5 2,2-Dimethylbutane C6H140,000 1 to 0,5 2,3-Dimethylbutane C6H140,00
39、0 1 to 0,5 2-Methylpentane C6H140,000 1 to 0,5 3-Methylpentane C6H140,000 1 to 0,5 n-Hexane C6H140,000 1 to 0,5 Benzene C6H60,000 1 to 0,5 Cyclohexane C6H120,000 1 to 0,5 HeptanescC7H160,000 1 to 0,5 Methylcyclohexane C7H140,000 1 to 0,5 Toluene C7H80,000 1 to 0,5 OctanesdC8H180,000 1 to 0,5 Xylenes
40、eC8H100,000 1 to 0,5 NOTE The analysis may be extended under specific conditions (e.g. greater sample volume) to hydrocarbons heavier than C8, if present in mole fractions 1 mol/mol. aThese components are generally not present in natural gas, but in natural gas substitute. bThe separation of propane
41、 from propene is critical. Depending on the column in use this separation may not be achieved. cComponents included: n-heptane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,2-dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,2,3-trimethylbutane. Not all isomers c
42、an be separated from each other. dComponents included: n-octane, 2-methylheptane, 3-methylheptane, 4-methylheptane, dimethylcyclohexanes, 2,2-dimethylhexane, 2,3-dimethylhexane, 2,4-dimethylhexane, 2,5-dimethylhexane, 3,3-dimethylhexane, 3,4-dimethylhexane, 2,2,3-trimethylpentane, 2,2,4-trimethylpen
43、tane (i-octane), 2,3,3-trimethylpentane, 2,3,4-trimethylpentane, 2,2,3,3-tetramethylbutane. Not all isomers can be separated from each other. eComponents included: o-xylene, m-xylene, p-xylene. m- and p-xylene will not be separated from each other. 33 Principle 3.1 Analysis of natural gas samples De
44、termination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and hydrocarbons from C1to C8by gas chromatography using three capillary columns. A PLOT1)precolumn is used for the separation of carbon dioxide (CO2) and ethane (C2H6). A molecular sieve PLOT column is used for the separation of the
45、permanent gases helium (He), hydrogen (H2), oxygen (O2), nitrogen (N2) and methane (CH4). A thick film WCOT2)column coated with an apolar phase is used for the separation of the C3to C8(and heavier) hydrocarbons. The permanent gases helium (He), hydrogen (H2), oxygen (O2), nitrogen (N2) and methane
46、(CH4) are detected with a thermal conductivity detector (TCD). The C2to C8hydrocarbons are detected with a flame ionization detector (FID). 3.2 Analysis of natural gas substitutes Carbon monoxide (CO) and carbon dioxide (CO2) are detected using an FID after reduction of the components to CH4by a met
47、hanizer. Use of a methanizer, makes it possible to detect CO and CO2at a mole fractions greater than 0,001 %. If the samples do not include CO or CO2or if the CO and/or the CO2mole fraction exceeds 0,02 %, a methanizer is not required. CO and CO2may then alternatively be detected with the TCD. When
48、analysing natural gas substitutes, the PLOT column described in 3.1 can also be used for the separation of ethyne (C2H2) and ethene (C2H4) and the molecular sieve PLOT column can also be used for the analysis of carbon monoxide (CO). 4 Materials 4.1 Carrier gases 4.1.1 Argon (Ar), W 99,999 % pure, f
49、ree from oxygen and water. 4.1.2 Nitrogen (N2), W 99,999 % pure or Helium (He) W 99,999 % pure. 4.2 Auxiliary gases 4.2.1 For FID detection: 4.2.1.1 Nitrogen (N2) or helium (He), W 99,996 % pure. 4.2.1.2 Air, free from hydrocarbon impurities, i.e. the mole fraction of hydrocarbons 0,2 % and CO2at mole fractions 0,02 %. 6.3.3.2 FID Connect the FID to two columns by means of a fitting. Use the FID for the detection of C2H2, C2H4 and C2H6eluting from the PoraPLOT U precolumn and all hydrocarbons above C3H6eluting from the WCOT methyl s
