1、BSI Standards PublicationBS ISO 17198:2014Dimethyl ether (DME) for fuels Determination of totalsulfur, ultraviolet fluorescencemethodBS ISO 17198:2014 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17198:2014.The UK participation in its preparation was entrust
2、ed to TechnicalCommittee PTI/13, Petroleum Testing and Terminology.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 its correctapplication
3、. The British Standards Institution 2014. Published by BSI StandardsLimited 2014ISBN 978 0 580 79349 3ICS 71.080.60; 75.160.20Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Co
4、mmittee on 31 December 2014.Amendments issued since publicationDate Text affectedBS ISO 17198:2014 ISO 2014Dimethyl ether (DME) for fuels Determination of total sulfur, ultraviolet fluorescence methodDME comme carburant ou combustible Dtermination de la teneur en soufre total Mthode par Fluorescence
5、 UltravioletINTERNATIONAL STANDARDISO17198First edition2014-11-15Reference numberISO 17198:2014(E)BS ISO 17198:2014ISO 17198:2014(E)ii ISO 2014 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2014All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or ut
6、ilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyri
7、ght officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 17198:2014ISO 17198:2014(E)Contents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Reagents and materials . 15 Ap
8、paratus . 36 Procedures 46.1 Apparatus preparation . 46.2 Apparatus calibration and verification 46.3 Verification . 66.4 Sampling and Measurement 76.5 Calculation and result . 97 Precision . 98 Test Report .10Annex A (informative) The report of the interlaboratory tests .11Bibliography .13 ISO 2014
9、 All rights reserved iiiBS ISO 17198:2014ISO 17198:2014(E)ForewordISO (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 committee
10、s. 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 ISO, also take part in the work. ISO collaborates closely with the Inter
11、national 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, Part 1. In particular the different approval criteria needed for the diff
12、erent 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 elements of this document may be the subject of patent rights. ISO sha
13、ll 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 received (see www.iso.org/patents). Any trade name used in this document
14、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 adherence to the WTO principles in the Technical Barriers to Trade (TBT
15、) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 28, Petroleum products and lubricants, Subcommittee SC 4, Classifications and specifications.iv ISO 2014 All rights reservedBS ISO 17198:2014ISO 17198:2014(E)IntroductionIn general, lar
16、ge amounts of DME in the international trade and domestic transportation can be executed using sea and/or various land transportations. From the feed stock of synthesis gas for DME production, and throughout the loading and transportation, there is a risk of increasing sulfur contents.Any sulfur com
17、pounds in DME contributes to SOxemissions. It can also cause corrosion in equipment. Therefore, sulfur content is tested accurately in process feeds, in finished products, as well as for compliance determinations required by regulatory authorities. It is common practice to analyse the sulfur, either
18、 by ultraviolet fluorescence or by oxidative microcoulometry.This International Standard specifies the procedure of test by ultraviolet fluorescence method. ISO 2014 All rights reserved vBS ISO 17198:2014BS ISO 17198:2014Dimethyl ether (DME) for fuels Determination of total sulfur, ultraviolet fluor
19、escence methodWARNING The use of this International Standard can involve hazardous materials, operations and equipment. This International Standard 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 e
20、stablish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.1 ScopeThis International Standard specifies a procedure of test for the sulfur content in dimethyl ether (DME) used as fuel by the ultraviolet (UV) fluorescence method. This proce
21、dure is applicable to determine the amount of total sulfur up to the value specified in ISO 16861.This test method will not measure sulfur that is not volatile under the practical conditions of the test, namely room temperature and atmospheric pressure.NOTE The precision of this method has been stud
22、ied for a limited set of samples and content levels by a limited amount of labs. It allows establishment of a quality specification of DME but cannot be considered as a full precision determination in line with the usual statistical methodology as in ISO 4259.2 Normative referencesThe following docu
23、ments, 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 16861, Petroleum produ
24、cts Fuels (class F) Specifications of dimethyl ether (DME)ISO 29945, Refrigerated non-petroleum-based liquefied gaseous fuels Dimethylether (DME) Method of manual sampling onshore terminals3 PrincipleA DME sample is directly injected into a UV fluorescence detector. The sample enters into a high-tem
25、perature combustion tube (1 000C to 1 100C), where the sulfur is oxidized to sulfur dioxide (SO2) in an oxygen-rich atmosphere. Water produced during the sample combustion is removed and the sample combustion gases are exposed to ultraviolet (UV) light. The SO2absorbs the energy from the UV light an
26、d is converted to excited SO2. The fluorescence emitted from the excited SO2as it returns to a stable state SO2is detected by a photomultiplier tube and the resulting signal is a measure of the sulfur contained in the sample.4 Reagents and materials4.1 Inert gas, argon or helium, of high purity grad
27、e with a minimum purity of 99,998 volume %.4.2 Oxygen, of high purity grade with a minimum purity of 99,75 volume %.INTERNATIONAL STANDARD ISO 17198:2014(E) ISO 2014 All rights reserved 1BS ISO 17198:2014ISO 17198:2014(E)4.3 Solvent.Use either the solvent specified in 4.3.1 or 4.3.2 or a solvent sim
28、ilar to that occurring in the sample under analysis. Correction for sulfur contribution from solvents used in standard preparation and sample dilution is required. Alternatively, use of a solvent with non-detectable sulfur contamination relative to the unknown sample makes the blank correction unnec
29、essary.4.3.1 n-hexane, reagent grade.4.3.2 Toluene, reagent grade.4.4 Sulfur compounds, compounds with a minimum purity of 99 mass %. Examples are given in 4.4.1 to 4.4.4. Where the purity of these compounds is less than 99 mass %, the concentrations and nature of all impurities are to be establishe
30、d. Certified reference materials from accredited suppliers are suitable alternatives to the compounds listed in 4.4.1 to 4.4.4.4.4.1 Dibutyl sulfide (DBS).4.4.2 Dibutyl disulfide (DBDS).4.4.3 Dibenzothiophene (DBT).4.4.4 Thionaphthene (benzothiophene) (TNA).4.5 Sulfur stock solution.Prepare a stock
31、solution of sulfur content approximately 1 000 mg/l by accurately weighing the appropriate quantity of sulfur compound (4.4) in a volumetric flask (5.9). Ensure complete dissolution with solvent (4.3). Calculate the exact sulfur concentration of the stock solution to the nearest 1 mg/l. This stock s
32、olution is used for the preparation of calibration standards. As an alternative procedure, a sulfur stock solution of approximately 1 000 mg/kg can be prepared by accurately weighing the appropriate quantity of sulfur compound (4.4). Take precautions to ensure that evaporation of the solvent and/or
33、sulfur compounds is not causing weighing errors.4.6 Calibration standards.Prepare the calibration standards by dilution of the stock solution (4.5) with the selected solvent (4.3). Calculate the exact sulfur content of each calibration standard.Calibration standards with a known sulfur concentration
34、, in mg/l or mg/kg, can be obtained with a volume/volume (or mass/mass) dilution of the stock solution at 1 000 mg/l or mg/kg. Other practices are possible but those mentioned above avoid any density correction.New calibration standards should be prepared on a regular basis depending upon the freque
35、ncy of use and age. When stored at low temperature, typically in a refrigerator, the calibration standards, with a sulfur content above 30 mg/kg or mg/l have at least a one month use of life. Below this sulfur content (30 mg/kg), the shelf life should be reduced.4.7 Quality control samples.These are
36、 stable samples representative of the materials being analysed, that have a sulfur content that is known by this test method over a substantial period of time. Alternatively, there are standard materials with a certified value commercially available. Ensure before use that the material is within its
37、 shelf life.2 ISO 2014 All rights reservedBS ISO 17198:2014ISO 17198:2014(E)5 Apparatus5.1 Furnace, comprising an electric device, capable of maintaining a temperature sufficient to pyrolyse all of the sample and oxidize all sulfur to sulfur dioxide (SO2).Follow manufacturers direction for the setti
38、ng of the temperature.It can be set either in a horizontal or vertical position.5.2 Combustion tube, of quartz, constructed to allow the direct injection of the sample into the heated oxidation zone of the furnace (5.1).The combustion tube shall have side arms for the introduction of oxygen and carr
39、ier gas. The oxidation section shall be large enough to ensure complete combustion of the sample. It can be set either in a horizontal or vertical position.5.3 Flow controllers, capable of maintaining a constant supply of oxygen and carrier gas.5.4 Vapour drier, capable of removing water vapour form
40、ed during combustion prior to measurement by the detector (5.5).5.5 UV fluorescence detector, a selective and quantitative detector capable of measuring light emitted from the fluorescence of sulfur dioxide by UV light.5.6 Microsyringe, capable of accurately delivering between 5 l and 50 l quantitie
41、s. Follow the manufacturers instructions for determining the length of the needle required. For vertical injection, syringes with a polytetrafluoroethylene (PTFE) plunger are recommended.5.7 Sample inlet system, positioned either vertically or horizontally. It shall consist of a direct-injection inl
42、et system capable of allowing the quantitative delivery of the material to be analysed into an inlet carrier stream which directs the sample into the oxidation zone at a controlled and repeatable rate. A syringe drive mechanism, which discharges the sample from the microsyringe at a constant rate of
43、 approximately 1 l/s maximum, is required.Key1 sample injection hole 6 dehumidifier2 inert gas 7 gas outlet3 combustion tube 8 ultraviolet light source4 oxygen 9 ultraviolet fluorescence detector5 combustion furnace 10 count number indicatorFigure 1 Test apparatus for ultraviolet fluorescence method
44、 (example) ISO 2014 All rights reserved 3BS ISO 17198:2014ISO 17198:2014(E)5.8 Balance, capable of weighing with an accuracy of at least 0,1 mg.5.9 Volumetric flasks, Class A one-mark volumetric flasks, conforming to ISO 1042, of appropriate capacities, including 100 ml, for the preparation of sulfu
45、r stock solution (4.5) and calibration standards (4.6).6 Procedures6.1 Apparatus preparation6.1.1 Assemble the apparatus and check for leaks according to the manufacturers instructions.6.1.2 Adjust the inlet pressure and flow rate of each gas according to the manufacturers instructions.6.1.3 Refer t
46、o the manufacturers instructions to set the temperature of the furnace (5.1) high enough to ensure all sulfur pyrolysis and oxidation, typically 1 100 C in the case of a one-temperature-zone furnace or 750 C for pyrolysis, and 1 000 C to 1 100 C for oxidation in the case of a two-temperature-zone fu
47、rnace.6.1.4 Adjust the instrument sensitivity and baseline stability, and perform instrument blanking procedures following the manufacturers guidelines. Ensure that the UV light is stable before measurement.NOTE For the UV light, a warm-up time of at least 30 min is usually required.6.2 Apparatus ca
48、libration and verification6.2.1 Multi-point calibration6.2.1.1 Prepare a series of calibration standards (5.6) by carrying out dilutions of the stock solution (5.5) with the selected solvent (5.3) to cover the range of operation (see Table 1 for examples). The number of calibration standards used in
49、 construction of the calibration curve can vary but it should not be less than four.Table 1 Examples of calibration standardsSulfur content approximate value of samplemg/kgSulfur content of standardsg/L0,5 11 22 45 106.2.1.2 Flush the microsyringe (5.6) several times with the solution to be analysed and ensure that the final liquid column in the syringe contains no bubbles.6.2.1.3 Using one of the techniques described in 6.2.1.3.1 or 6.2.1.3.2, quantitatively analyse an appropriate sample size as specified by the manufact
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