1、BSI Standards PublicationBS EN ISO 16960:2014Natural gas Determinationof sulfur compounds Determination of total sulfurby oxidative microcoulometrymethodBS EN ISO 16960:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN ISO16960:2014.The UK participation in it
2、s preparation was entrusted to TechnicalCommittee PTI/15, Natural Gas and Gas Analysis.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for it
3、s correctapplication. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 75292 6ICS 75.060Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strat
4、egy Committee on 31 October 2014.Amendments issued since publicationDate Text affectedEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 16960 October 2014 ICS 75.060 English Version Natural gas - Determination of sulfur compounds - Determination of total sulfur by oxidative microcoulometry me
5、thod (ISO 16960:2014) Gaz naturel - Dtermination des composs soufrs - Dtermination de la teneur totale en soufre par microcoulomtrie oxydante (ISO 16960:2014) Erdgas - Bestimmung von Schwefelverbindungen - Bestimmung des Schwefelgehalts mittels oxidativem mikrocoulometrischen Verfahren (ISO 16960:20
6、14) This European Standard was approved by CEN on 24 August 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-to-date lists and bibliographical
7、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
8、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, Former Yugoslav Republic of Mace
9、donia, 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. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUR
10、OPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 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 16960:2014 EBS EN ISO 16960:2014EN ISO 16960:2014 (E) 3 Foreword This document (E
11、N ISO 16960:2014) has been prepared by Technical Committee 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 April 2015, and conflicting national standards shall be withdra
12、wn at the latest by April 2015. 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 patent rights. According to the CEN-CENELEC Internal Regulations, the
13、 national 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
14、, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. Endorsement notice The text of ISO 16960:2014 has been approved by CEN as EN ISO 16960:2014 without any modification. BS EN ISO 16960:2014ISO
15、 16960:2014(E) ISO 2014 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Test principle . 14 Reagents 15 Apparatus . 25.1 Converter . 25.2 Titration cell 25.3 Microcoulometer . 25.4 Flow controller 25.5 Electromagnetic agitator 25.6 Medical syringe .
16、25.7 Volumetric flask . 26 Test preparation . 26.1 Preparation of electrolyte 26.2 Reference sample 26.3 Apparatus installation 36.4 Preparation of instrument 36.5 Check and adjustment of the instrument . 36.6 Determination of recovery factor of sulfur . 37 Test procedure 47.1 Sampling . 47.2 Sample
17、 injection and measurement . 48 Calculation 48.1 Volume conversion 48.2 Calculation of total sulfur mass concentration in the gas sample 59 Precision . 69.1 General . 69.2 Repeatability . 6Bibliography 7BS EN ISO 16960:2014ISO 16960:2014(E)ForewordISO (the International Organization for Standardizat
18、ion) 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 r
19、epresented 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 d
20、evelop 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
21、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 duri
22、ng 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 mea
23、ning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 193
24、, Natural gas, Subcommittee SC 1, Analysis of natural gas.iv ISO 2014 All rights reservedBS EN ISO 16960:2014ISO 16960:2014(E)IntroductionThree methods for determination of sulfur compounds in natural gas already exist as International Standards: ISO 6326-3, Natural gas Determination of sulfur compo
25、unds Part 3: Determination of hydrogen sulfide, mercaptan sulfur and carbonyl sulfide sulfur by potentiometry; ISO 6326-5, Natural gas Determination of sulfur compounds Part 5: Lingener combustion method; ISO 19739, Natural gas Determination of sulfur compounds using gas chromatography. ISO 2014 All
26、 rights reserved vBS EN ISO 16960:2014BS EN ISO 16960:2014Natural gas Determination of sulfur compounds Determination of total sulfur by oxidative microcoulometry methodWARNING The use of this International Standard can involve hazardous material, operations, and equipment. This International Standa
27、rd does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use.1 ScopeThis Internatio
28、nal Standard specifies a method for the determination of total sulfur in the range from 1 mg/m3to 200 mg/m3in pipeline natural gas by oxidative microcoulometry. Natural gas with sulfur contents above 200 mg/m3can be analysed after dilution with a suitable sulfur-free solvent.2 Normative referencesTh
29、e following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3696,
30、Water for analytical laboratory use Specification and test methodsISO 6142, Gas analysis Preparation of calibration gas mixtures Gravimetric methodISO 6144, Gas analysis Preparation of calibration gas mixtures Static volumetric methodISO 6146, Gas analysis Preparation of calibration gas mixtures Man
31、ometric methodISO 10715, Natural gas Sampling guidelines3 Test principleA gas sample containing sulfur is mixed with oxygen in a quartz furnace tube in order to convert the sulfur compounds to sulfur dioxide by oxidative pyrolysis. The obtained sulfur dioxide enters the titration cell along with car
32、rier gas and reacts with iodine contained therein. The consumed iodine is complemented by the electrolysis of potassium iodide. In accordance with Faradays law of electrolysis, the sulfur concentration in the gas sample can be calculated from the consumed electric quantity by electrolysis and correc
33、ted by comparison to a reference standard sample.4 Reagents4.1 Test water, conforming to the requirements of Grade 3 of ISO 3696,4.2 Glacial acetic acid, analytical purity.4.3 Potassium iodide, analytical purity.4.4 Oxygen, minimum purity 99,99 % (by volume fraction), maximum volume fraction of sulf
34、ur containing gases 0,01 % (by volume fraction).INTERNATIONAL STANDARD ISO 16960:2014(E) ISO 2014 All rights reserved 1BS EN ISO 16960:2014ISO 16960:2014(E)4.5 Carrier gas, argon, helium, or nitrogen with a minimum purity 99,99 % (by volume fraction), maximum volume fraction of sulfur containing gas
35、es 0,01 % (by volume fraction).5 Apparatus5.1 ConverterThere are three independent heating sections in a converter: preheating section (800 C 20 C), combustion section (900 C 20 C), and exit section (800 C 20 C).5.2 Titration cellInstall a pair of electrolysis electrodes and a pair of indicator-refe
36、rence electrodes in the cell.5.3 MicrocoulometerElectrolysis commences automatically when there is a reduction in the concentration of iodine caused by the presence of sulfur dioxide in the titration cell, to maintain the concentration of iodine at its original level. The microcoulometer can automat
37、ically record the electrolysis time and current and directly display the sulfur content.5.4 Flow controllerProvides the specified flow rates at the outlet.5.5 Electromagnetic agitatorProvides the specified rotational rates in the titration cell.5.6 Medical syringeAir tight syringes of volumes 0,25 m
38、l, 1 ml, 2 ml, and 5 ml. Syringe-delivered volumes should be calibrated by weighing pure water prior to initial use. Periodic calibration might be required thereafter.5.7 Volumetric flaskOne standard laboratory volumetric flask of nominal 25 ml volume.6 Test preparation6.1 Preparation of electrolyte
39、Weigh 0,5 g potassium iodide, dissolve it in 100 ml water, add in 5 ml glacial acetic acid, and then dilute the solvent to 1 L with water. The electrolyte should be stored in a brown reagent bottle. The electrolyte shelf life after preparation is three months.6.2 Reference sampleUse calibration gas
40、mixtures of sulfur compounds prepared according to ISO 6142, ISO 6144, or ISO 6146. Sulfur concentration in the calibration gas mixtures shall be close to that in the tested sample.It is recommended that sulfur compounds in the calibration gas mixture were hydrogen sulfide (H2S) in a methane matrix.
41、2 ISO 2014 All rights reservedBS EN ISO 16960:2014ISO 16960:2014(E)6.3 Apparatus installationInstall the apparatus following the instruction. Connect the carried gas tube and oxygen tube. An example of a typical microcoulometer set-up is given in Figure 1.Key1 microcoulometer2 titration cell3 electr
42、omagnetic stirrer4 reforming furnace5 quartz furnace tube6 injection port7 flow meter8 needle valveFigure 1 Typical microcoulometric set-up6.4 Preparation of instrumentReplace the silicone rubber plug in the injection port. Regulate the flow rate of carrier gas and oxygen to the values specified by
43、the apparatus. Then switch on the electromagnetic stirrer, adjust stirring speed to produce a slight vortex in the electrolyte6.5 Check and adjustment of the instrumentCheck and adjust all the operating parameters according to the instruction manual of the instrument.6.6 Determination of recovery fa
44、ctor of sulfurInstall software of microcoulometer and display the sulfur recovery factor using computer software, typically installed on a person computer (PC), suited for the microcoulometer being used.6.6.1 Sampling and injectionTake samples after flushing the syringe with the gas standard sample
45、four to five times. The syringe plunger should be pushed to the required scale by the gas pressure in the bottle when sampling. Insert the syringe into the injection port, the injection rate is about 0,15 ml/s to 0,2 ml/s and the injection volume is typically 0,25 ml to 5 ml. ISO 2014 All rights res
46、erved 3BS EN ISO 16960:2014ISO 16960:2014(E)6.6.2 MeasurementSwitch the instrument to correction factor mode. Enter the concentration of the standard sample and the injection volume. Carry out the determination of the microcoulometer recovery factor by injecting a standard sample according to the me
47、thod described in 6.6.1. The sulfur recovery factor displayed on the instrument can be used when the relative standard deviation of five consecutive recovery factors is equal or less than 2 %, take the average of these five consecutive values as the recovery factor of the instrument used for measure
48、ments.In case the recovery factor is less than 75 % (F in Formula (3), 2 decimal places), it is necessary to identify the reason23.7 Test procedure7.1 Sampling7.1.1 Sampling from natural gas pipelineSampling shall be performed in accordance with ISO 10715.7.1.2 Sampling from gas cylindersAnalysis sh
49、ould be performed as soon as possible after receiving the samples. Sampling shall be performed in accordance with 6.6.1.7.2 Sample injection and measurementSwitch the instrument to sample measurement mode. Input volume parameters into the microcoulometer software (corrected to reference conditions). Carry out the determination of the sample recovery factor by injecting the sample according to the method described in 6.6.1. The sulfur recovery factor displayed on the instrument can be used. The sulfur
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