1、October 2014English price group 15No 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!%;w(“2248405www.din.deDDIN
2、 EN ISO 6974-5Natural gas Determination of composition and associated uncertainty by gaschromatography Part 5: Isothermal method for nitrogen, carbon dioxide, C to1C hydrocarbons and C hydrocarbons5 6+(ISO 6974-5:2014);English version EN ISO 6974-5:2014,English translation of DIN EN ISO 6974-5:2014-
3、10Erdgas Bestimmung der Zusammensetzung und der zugehrigen Unsicherheit durchGaschromatographie Teil 5: Isothermes Verfahren fr Stickstoff, Kohlenstoffdioxid, C1- bisC5-Kohlenwasserstoffe und C6+-Kohlenwasserstoffe(ISO 6974-5:2014);Englische Fassung EN ISO 6974-5:2014,Englische bersetzung von DIN EN
4、 ISO 6974-5:2014-10Gaz naturel Dtermination de la composition et de lincertitude associe par chromatographie enphase gazeuse Partie 5: Mthode isotherme pour lazote, le dioxyde de carbone, les hydrocarburesC1 C5 e t C6+ (I SO 6974-5:2014);Version anglaise EN ISO 6974-5:2014,Traduction anglaise de DIN
5、 EN ISO 6974-5:2014-10SupersedesDIN EN ISO 6974-5:2002-06www.beuth.deDocument comprises 32 pages09.14Translation by DIN-Sprachendienst.In case of doubt, the German-language original shall be considered authoritative.DIN EN ISO 6974-5:2014-10 2 A comma is used as the decimal marker. National foreword
6、 The text of this document (EN ISO 6974-5:2014) has been prepared by Technical Committee ISO/TC 193 “Natural gas” (Secretariat: NEN, Netherlands). The responsible German body involved in its preparation was the DIN-Normenausschuss Materialprfung (DIN Standards Committee Materials Testing), Working C
7、ommittee NA 062-05-73 AA Gasanalyse und Gas-beschaffenheit. DIN EN ISO 6974-2 consists of the following parts, under the general title Natural gas Determination of composition and associated uncertainty by gas chromatography: Part 1: General guidelines and calculation of composition Part 2: Uncertai
8、nty calculations Part 3: Determination of hydrogen, helium, oxygen, nitrogen, carbon dioxide and hydrocarbons up to C8using two capillary columns and one packed column Part 4: Determination of nitrogen, carbon dioxide and C1up to C5and C6+hydrocarbons for a laboratory and on-line measuring system us
9、ing two columns Part 5: Isothermal method for nitrogen, carbon dioxide, C1up to C5hydrocarbons and C6+hydrocarbons Part 6: Determination of helium, oxygen, nitrogen, carbon dioxide and C1up to C8hydrocarbons using three capillary columns The DIN Standards corresponding to the International Standards
10、 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 6976 DIN EN ISO 6976 ISO 10723 DIN EN ISO 10723 Amendments This standard differs from DIN EN ISO 6974-5:2002-06 as follows: a) component working ranges (Table 1) have been modified; b) referen
11、ces to DIN EN ISO 6974-1 and DIN EN ISO 6974-2 have been updated; c) Annex A “Example of application” has been added. Previous editions DIN EN ISO 6974-5: 2002-06 DIN EN ISO 6974-5:2014-10 3 National Annex NA (informative) Bibliography DIN EN ISO 6974-1, Natural gas Determination of composition and
12、associated uncertainty by gas chroma-tography Part 1: General guidelines and calculation of composition DIN EN ISO 6974-2, Natural gas Determination of composition and associated uncertainty by gas chroma-tography Part 2: Uncertainty calculations DIN EN ISO 6976, Natural gas Calculation of calorific
13、 values, density, relative density and Wobbe index from composition DIN EN ISO 10723, Natural gas Performance evaluation for analytical systems DIN EN ISO 6974-5:2014-10 4 This page is intentionally blank EN ISO 6974-5July 2014 ICS 75.060 Supersedes EN ISO 6974-5:2001English VersionNatural gas - Det
14、ermination of composition and associateduncertainty by gas chromatography - Part 5: Isothermal methodfor nitrogen, carbon dioxide, C1to C5hydrocarbons and C6+hydrocarbons (ISO 6974-5:2014)Gaz naturel - Dtermination de la composition et delincertitude associe par chromatographie en phasegazeuse - Par
15、tie 5: Mthode isotherme pour lazote, ledioxyde de carbone, les hydrocarbures C1 C5 et C6+(ISO 6974-5:2014)Erdgas - Bestimmung der Zusammensetzung und derzugehrigen Unsicherheit durch Gaschromatographie - Teil 5: Isothermes Verfahren fr Stickstoff, Kohlenstoffdioxid,C1- bis C5-Kohlenwasserstoffe und
16、C6+-Kohlenwasserstoffe (ISO 6974-5:2014)This European Standard was approved by CEN on 28 June 2014. 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-
17、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 transl
18、ation 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
19、, 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 United Kingdom. CEN-CENELEC Management Centre: Avenue M
20、arnix 17, B-1000 Brussels 2014 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN ISO 6974-5:2014 EEUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGEUROPEAN STANDARDNORME EUROPENNEEUROP
21、ISCHE NORM2DIN EN ISO 6974-5:2014-10 EN ISO 6974-5:2014 (E) Contents Page Foreword . 3 Introduction . 4 1 Scope . 5 2 Normative references. 6 3 Principle 6 4 Materials 8 5 Apparatus 8 6 Scheme of the configuration . 10 7 Procedure 11 7.1 Control of the apparatus . 11 7.2 Operation of the apparatus .
22、 12 8 Expression of results . 15 8.1 Uncertainty 15 8.2 Test report . 15 Annex A (informative) Example of application 16 Annex B (informative) Procedure for Setting Valve timings and Restrictor Setting . 26 Bibliography 28 ForewordThis document (EN ISO 6974-5:2014) has been prepared by Technical Com
23、mittee ISO/TC 193 Natural gas . 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 January 2015, and conflicting national standards shall be withdrawn at the latest by January 2015. Attention is draw
24、n 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 patent rights. This document supersedes EN ISO 6974-5:2001. According to the CEN-CENELEC Internal Regulations, the nat
25、ional standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Li
26、thuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 6974-5:2014 has been approved by CEN as EN ISO 6974-5:2014 without any modification. “ ”3DIN EN ISO 6974-5:201
27、4-10EN ISO 6974-5:2014 (E)IntroductionThis part of ISO 6974 describes a method for the analysis of natural gas that is commonly used for online process applications, but can be applied to laboratory instruments. The compositional data obtained are used for the calculation of calorific value, density
28、 and Wobbe index.It is assumed that the natural gas does not contain any oxygen at source and that any oxygen which may be present is due to contamination during sampling.The primary use of this chromatographic method is the calculation of calorific value (CV) according to ISO 6976. It is based on a
29、 column switching technique in which multiple columns, chosen for their separating ability for particular groups of components, are switched under automatic control.Only one injection is necessary and the first phase of the method involves accelerated backflush of C6+ (which is measured as a recombi
30、ned “pseudo component” rather than by the summation of individual component measurements). Lighter components (nitrogen, methane, carbon dioxide and ethane) are stored on the appropriate separating column while the heavier, C3to C5hydrocarbons are eluted. The lighter components are then separated by
31、 redirecting carrier gas on to the appropriate column.A Thermal Conductivity Detector (TCD) is used for measurement of the above components.When the method is first set up, the repeatability of measurement is established by repetitive analysis of a cylinder of test gas, commonly a typical natural ga
32、s. For each component, a control chart showing the mean value, and the bounds representing 2 and 3 standard deviations, is drawn up. Subsequently, this test gas is analysed after each calibration of the analyser, and the results are compared with the data in the control charts. The performance of th
33、e analyser is assessed by this procedure.Any change in the method setup can give rise to differences in component responses and hence (where applied) to calculated uncertainties. In these circumstances fitting data to an existing control chart is not a suitable procedure, and the operations that wer
34、e undertaken when the method was first set up shall be repeated.This part of ISO 6974 provides one of the methods that may be used for determining the compositions of natural gas in accordance with ISO 6974-1 and ISO 6974-2.4DIN EN ISO 6974-5:2014-10 EN ISO 6974-5:2014 (E) 1 ScopeThis part of this I
35、nternational Standard describes a gas chromatographic method for the quantitative determination of the content of nitrogen, carbon dioxide and C1to C5hydrocarbons individually and a composite C6+ measurement, which represents all hydrocarbons of carbon number 6 and above in natural gas samples. It i
36、s applicable to the analysis of gases containing constituents within the working ranges given in Table 1.Table 1 Component working rangesComponentMole fraction%Min. Max.Nitrogen N20,1 22Carbon dioxide CO20,05 15Methane CH434 100Ethane C2H60,1 23Propane C3H80,05 10iso-Butane i-C4H100,01 2,0n-Butane n
37、-C4H100,01 2,0neo-Pentane neo-C5H120,005 0,35iso-Pentane i-C5H120,005 0,35n-Pentane n-C5H120,005 0,35Hexanes + C6+ 0,005 0,35NOTE 1 The working ranges in Table 1 are those for which the method has been shown to be satisfactory, and are offered for guidance. However, there is no reason why wider rang
38、es should not be used, provided that the successful measurement of such wider ranges has been demonstrated.NOTE 2 Hydrocarbons above n-pentane are expressed as the “pseudo-component” C6+ which is measured as one composite peak and calibrated as such. The properties of C6+ are calculated from an exte
39、nded analysis of the individual C6and higher hydrocarbons.NOTE 3 Oxygen is not a normal constituent of natural gas and would not be expected to be present in gas sampled to an online instrument. If any oxygen is present as a result of air contamination, it will be measured with the nitrogen. The res
40、ulting measured (nitrogen + oxygen) value will be in error to a small extent because of the slight difference between the detector responses of oxygen and nitrogen.NOTE 4 The helium and argon contents are assumed to be sufficiently small and unvarying that they need not be analysed for.NOTE 5 The ga
41、s sample shall not contain any hydrocarbon condensate and/or water.5DIN EN ISO 6974-5:2014-10EN ISO 6974-5:2014 (E)2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the
42、 edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 6974-1, Natural gas Determination of composition and associated uncertainty by gas chromatography Part 1: General guidelines and calculation of compositionISO 6974-2,
43、Natural gas Determination of composition and associated uncertainty by gas chromatography Part 2: Uncertainty calculations3 PrincipleFigure 1 is a flowchart showing the steps involved in the analytical process. It is based on more detailed flowcharts in ISO 6974-1 and ISO 6974-2, simplified to repre
44、sent the procedure described in this part. References are given at each step to the relevant clause in this part and, where appropriate, to the relevant clauses in ISO 6974-1 and ISO 6974-2.6DIN EN ISO 6974-5:2014-10 EN ISO 6974-5:2014 (E) Figure 1 Operational flowchartNOTE The steps referred to in
45、Figure 1 are identical to the steps in flowcharts A and B in ISO 6974-1 Step 5 refers to the use of relative response factors for indirectly measured components. Indirect components are not used in this part of ISO 6974, so step 5 is not used.The chromatographic method uses a column switching/backfl
46、ush arrangement, configured as shown in Figure 2. The sample is injected onto a boiling-point column which is divided into short and long sections (columns 1 and 2). The long section (column 2) provides separation of C3to C5hydrocarbons, while C6and heavier hydrocarbons are retained on the short sec
47、tion (column 1), from which they are 7DIN EN ISO 6974-5:2014-10EN ISO 6974-5:2014 (E)backflushed and measured by the detector as a single peak. Two six-port valves can handle the sample injection and backflushing operations, or they may be dealt with together by a single 10-port valve.Nitrogen, carb
48、on dioxide, methane and ethane pass rapidly and unresolved through the boiling-point column onto a porous polymer bead column (column 3), suitable for their separation. A six-port valve either connects this column or by-passes it during measurement of C3to C5components.The separations that occur in
49、the columns are as follows:Column 1 Retains C6+ components ready for backflushing as one composite peak.Column 2 Separates Propane, iso-Butane, n-Butane, neo-Pentane, iso-Pentane and n-Pentane, (which elute after C6+ has left column 1).Column 3 Stores and separates Nitrogen, Methane, Carbon Dioxide and Ethane which elute after n-Pentane has left column 2.4 Materials4.1 Carrier gas, Helium (He), 99,995 % pure, free from oxygen and water.4.2 Auxiliary gases, compressed air, for valve actuation (If consumption is l
