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1、 Reference number ISO 20847:2004(E) ISO 2004 INTERNATIONAL STANDARD ISO 20847 First edition 2004-03-15 Petroleum products Determination of sulfur content of automotive fuels Energy-dispersive X-ray fluorescence spectrometry Produits ptroliers Dtermination de la teneur en soufre des carburants pour a
2、utomobiles Spectromtrie de fluorescence de rayons X dispersive en nergie Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction or networking permitted witho
3、ut license from IHS -,-,- ISO 20847:2004(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer perfor
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6、cretariat at the address given below. ISO 2004 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the
7、address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2004 All rights reserved Copyright International Organization
8、 for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 20847:2004(E) ISO 2004 All rights reserved iii Contents Page Forewordiv Introdu
9、ction v 1 Scope1 2 Normative references .1 3 Principle.1 4 Reagents and materials2 5 Apparatus.2 6 Sampling and sample handling.3 7 Apparatus preparation3 8 Calibration4 9 Procedure.6 10 Calculation.6 11 Expression of results6 12 Precision6 13 Test report7 Annex A (informative) Interferences.8 Annex
10、 B (informative) Guidelines for measuring low sulfur contents (less than 100 mg/kg)10 Bibliography .11 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction
11、 or networking permitted without license from IHS -,-,- ISO 20847:2004(E) iv ISO 2004 All rights reserved 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 nor
12、mally 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 organizations, governmental and non-governmental, in liaison with ISO, also take part in
13、the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepar
14、e International Standards. Draft International Standards adopted by the technical committees 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 som
15、e 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. ISO 20847 was prepared by Technical Committee ISO/TC 28, Petroleum products and lubricants. Copyright International Organization for Standardizatio
16、n Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 20847:2004(E) ISO 2004 All rights reserved v Introduction This International Standard is directed
17、specifically at the lower end of the concentration range covered in ISO 8754 (3 in the Bibliography), which covers sulfur contents from 0,01 % (m/m) up to 5,00 % (m/m). By restriction of instrument type, a better signal to background ratio for sulfur K emission is assured and by the use of matrix ma
18、tched calibration standards or other means of matrix corrections (as detailed below), the precision and accuracy of results for samples having varying C:H mass ratios and oxygen contents are improved. A knowledge of the general composition of the sample for analysis is advantageous in obtaining the
19、best test result. Where matrix matching is not used and where the C:H mass ratio of the test sample is known or can be determined, accuracy may be improved by the use of the equation given in A.2.2 to correct the result to the C:H mass ratio of the calibration standards, i.e. the reference diluent o
20、il (4.1). Some instruments include the capability for the separate measurement of scattered radiation from the X-ray tube, and notes for information are provided in A.2.3 on the use of this scattered radiation for compensation for matrix effects in the test sample. Copyright International Organizati
21、on for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under li
22、cense with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 20847:2004(E) ISO 2004 All rights reserved 1 Petroleum products Determination of sulfur content of au
23、tomotive fuels Energy-dispersive X-ray fluorescence spectrometry WARNING The use of this International Standard may 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 responsibil
24、ity of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies an energy dispersive X-ray fluorescence (EDXRF) test method for the determination
25、of the sulfur content of motor gasolines, including those containing up to 2,7 % (m/m) oxygen, and of diesel fuels, including those containing up to 5 % (V/V) fatty acid methyl ester (FAME), having sulfur contents in the range 30 mg/kg to 500 mg/kg. Other products may be analysed and other sulfur co
26、ntents may be determined according to this test method; however, no precision data for products other than automotive fuels and for results outside the specified range have been established for this International Standard. For reasons of spectral overlap, this International Standard is not applicabl
27、e to leaded motor gasolines, lead-replacement gasolines containing 8 mg/kg potassium to 20 mg/kg potassium, or to products and feedstocks containing lead, silicon, phosporus, calcium, potassium or halides at concentrations greater than one-tenth of the concentration of sulfur measured. NOTE For the
28、purposes of this International Standard, the terms “% (m/m)” and “% (V/V)” are used to represent the mass fraction and the volume fraction of a material, respectively. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated referenc
29、es, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 3170:2004, Petroleum liquids Manual sampling ISO 3171:1988, Petroleum liquids Automatic pipeline sampling 3 Principle The test portion, in a cup fitted wi
30、th an X-ray transparent window, is placed in a beam of exciting radiation from an X-ray tube. The intensity of the sulfur K characteristic X-radiation is measured, and the number of accumulated counts is compared with a calibration curve constructed from sulfur standards covering the range of sulfur
31、 contents under examination. NOTE The exciting radiation may be either direct, or indirect via a secondary target. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo
32、reproduction or networking permitted without license from IHS -,-,- ISO 20847:2004(E) 2 ISO 2004 All rights reserved 4 Reagents and materials 4.1 Diluent oil 4.1.1 The reference diluent oil is white oil (light paraffin oil) of high purity grade, with a sulfur content of 1 mg/kg maximum. However, if
33、only one type of matrix is to be analysed (e.g. motor gasoline), the accuracy of results may be improved by using a matrix-matched diluent. These should match approximately the aromatic and oxygen content of the material to be analysed, and should consist of high purity components of less than 1 mg/
34、kg sulfur content. NOTE Suitable components for the matched matrix diluent include heptane, 2,2,4-trimethylpentane, toluene, xylenes, ethanol, methyl tertiary butyl ether (MTBE), ethyl tertiary butyl ether (ETBE), tertiary amyl methyl ether (TAME) and fatty acid methyl ester (FAME). 4.1.2 For the an
35、alysis of diesel fuels containing FAME at contents greater than 5 % (V/V), a matched matrix diluent oil of the white oil with FAME shall be used. 4.2 Sulfur compounds 4.2.1 General Sulfur compounds of known sulfur content shall be used for the preparation of the primary standards. The compounds give
36、n in 4.2.2 to 4.2.5 are suitable, and their nominal sulfur contents are given. Where the purity of these compounds is less than 99 % (m/m), either the concentrations and nature of all impurities are to be known or certified reference materials shall be used. 4.2.2 Dibenzothiophene (DBT), with a nomi
37、nal sulfur content of 17,399 % (m/m). 4.2.3 Dibutylsulfide (DBS), with a nominal sulfur content of 21,915 % (m/m). 4.2.4 Thionaphthene (Benzothiophene) (TNA), with a nominal sulfur content of 23,890 % (m/m). 4.2.5 Dibutyldisulfide (DBDS), with a nominal sulfur content of 35,950 % (m/m). 4.3 Referenc
38、e materials Certified reference materials (CRMs) from accredited suppliers, containing a range of sulfur concentrations, are suitable alternatives to the compounds listed in 4.2 for use as calibration standards. 4.4 Quality control samples Stable samples representative of the materials being analyse
39、d, that have a sulfur content that is known by this test method over a substantial period of time, or supplied commercially with a certified value. Ensure before use that the material is within its shelf life. 5 Apparatus 5.1 Energy-dispersive X-ray fluorescence analyser 5.1.1 Energy-dispersive X-ra
40、y fluorescence analyser, having facilities for measuring and subtracting the background to give net sulfur intensities. The instrument shall be capable of measuring the content of sulfur at 50 mg/kg with an error due to counting statistics of 3 % relative standard deviation (RSD) maximum. 5.1.2 Sour
41、ce of X-ray excitation, with significant flux at X-ray energies above 2,5 keV. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=NASA Technical Standards 1/9972545001 Not for Resale, 04/20/2007 03:48:46 MDTNo reproduction or networking permitted
42、 without license from IHS -,-,- ISO 20847:2004(E) ISO 2004 All rights reserved 3 5.1.3 Removable sample cup, providing a sample depth of at least 5 mm, and equipped with replaceable X-ray transparent film. NOTE The transparent film is normally of polyester or polycarbonate with a thickness between 2
43、 m and 6 m. Polyester film is the preferred choice as samples of very high aromatic content can dissolve polycarbonate film. There are possibly trace amounts of calcium in polyester film, but any absorption or enhancement effects would be cancelled out when samples and standards are analysed using t
44、he same material. It is important that samples, standards and blanks are measured using the same batch of film to avoid bias. 5.1.4 X-ray detector, with high sensitivity, and resolution not exceeding 800 eV at 2,3 keV. 5.1.5 Means of discriminating between sulfur K characteristic X-radiation and oth
45、er X-rays of higher energy (e.g. filters). 5.1.6 Signal conditioning and data handling electronics, including the functions of pulse counting, and a minimum of two energy regions (to correct for background X-rays). When matrix matching of samples and standards is not used, the instrument shall also
46、be able to measure an energy region corresponding to scattered radiation, and to use this measurement to compensate for matrix effects (see Annex A). The latter measurement can also be used as the second energy region specified above and used to calculate the background. NOTE Differences in carbon/h
47、ydrogen ratios, or oxygen contents, between samples and standards can cause matrix effects which may lead to a bias in the analytical result. 5.2 Analytical balance, single-pan or double-pan, capable of weighing to the nearest 0,1 mg. 5.3 Mixer, magnetic stirrer with PTFE-coated stirring rods. 5.4 F
48、lasks, of 100 ml capacity, narrow-necked, conical, and made of borosilicate glass. 6 Sampling and sample handling 6.1 Unless otherwise specified, samples shall be taken by the procedures described in ISO 3170 or ISO 3171. 6.2 Store samples which contain light fractions (e.g. motor gasoline and naphtha) in a refrigerator. 6.3 Mix samples by gently shaking by hand prior to the removal of the test portion. 6.4 Allow test portions to attain ambient temperature prior to analysis. 7 A