1、November 2007DEUTSCHE NORM English price group 8No part of this standard 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 75.160.20!$J3,“1391609
2、www.din.deDDIN EN 15490Ethanol as a blending component for petrol Determination of pHeEnglish version of DIN EN 15490:2007-11Ethanol zur Verwendung als Blendkomponente in Ottokraftstoff Bestimmung des pHe-WertesEnglische Fassung DIN EN 15490:2007-11www.beuth.deDocument comprises 12 pagesDIN EN 15490
3、:2007-11 2 National foreword This standard has been prepared by Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin” (Secretariat: NEN, Netherlands). The responsible German body involved in its preparation was the Nor
4、menausschuss Materialprfung (Materials Testing Standards Committee), Technical Committee NA 062-06-81 AA Gasfrmige und flssige Kraft- und Brennstoffe, Schmierstoffe und verwandte Produkte mit minerallstmmiger, synthetischer oder biologischer Herkunft of the Fachausschuss Minerall- und Brennstoffnorm
5、ung (FAM). EUROPEAN STANDARDNORME EUROPENNEEUROPISCHE NORMEN 15490August 2007ICS 71.080.60English VersionEthanol as a blending component for petrol - Determination ofpHeDtermination du pHeEthanol zur Verwendung als Blendkomponente inOttokraftstoff - Bestimmung des pHe-WertesThis European Standard wa
6、s approved by CEN on 30 June 2007.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 nation
7、alstandards may be obtained on application to the CEN 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 translationunder the responsibility of a CEN member into its own language and notif
8、ied to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta,
9、 Netherlands, Norway, Poland, Portugal,Romania, 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 2007 CEN All rights of exploitati
10、on in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 15490:2007: Ethanol comme base de mlange lessence -EN 15490:2007 (E) 2 Contents Page Foreword. 3 1 Scope 4 2 Normative references . 4 3 Terms and definitions. 4 4 Principle . 4 5 Reagents and materials 4 6 Apparat
11、us 5 7 Sampling and sample handling . 5 8 Apparatus preparation 5 9 pH meter and electrode system calibration . 5 10 Apparatus verification 6 11 Procedure 6 12 Expression of results 7 13 Precision 7 13.1 General. 7 13.2 Repeatability, r 7 13.3 Reproducibility, R . 7 14 Test report . 8 Annex A (infor
12、mative) Background to actual fuel specification needs 9 Bibliography . 10 EN 15490:2007 (E) 3 Foreword This document (EN 15490:2007) has been prepared by Technical Committee CEN/TC 19 “Gaseous and liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the secre
13、tariat of which is held by NEN. 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 February 2008, and conflicting national standards shall be withdrawn at the latest by February 2008. This document w
14、as prepared by CEN/TC 19s Ethanol Task Force and is based on an extract and translation from a French Wine Regulation 1. This method has been developed for European fuel ethanol specifications. Interlaboratory studies found that the method is not robust enough. Therefore it is better not to use it t
15、o determine the presence of any strong acids or alkalis that may be present in fuel ethanol. This Standard has insufficient precision to fulfill actual fuel specification needs (see Annex A). A test for strong acid and for the presence of alkaline substance will be developed by CEN/TC 19 to replace
16、the pHe test method. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Icel
17、and, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 15490:2007 (E) 4 1 Scope This European Standard describes a procedure for the determination of acid strength, as a pHe valu
18、e, of ethanol to be used as a blend component for gasoline. For further background on the applicability of this document, the user is referred to the information in Annex A. NOTE For the purposes of this European Standard, the term “% (V/V)” is used to represent the volume fraction. 2 Normative refe
19、rences The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 3170, Petroleum liquids Manual samp
20、ling (ISO 3170:2004) EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696:1987) 3 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1 pHe measure of the acid strength 4 Principle The pHe of a test porti
21、on of ethanol held at 22 C 2 C is measured using an electrode containing lithium chloride (LiCl) in an ethanol medium connected to a pH meter system. NOTE In non-aqueous media, it is not possible to carry out absolute pH measurements and a pHe value is not directly comparable to pH values of water s
22、olutions. 5 Reagents and materials Use only reagents of recognized analytical grade. 5.1 Buffer solutions, of pH (4,00 0,02), pH (7,00 0,02) and pH (10,00 0,02), within their valid period for use. CAUTION Buffer solutions can deteriorate with time and it is important that they are used within their
23、valid period of use. NOTE Buffer solutions may be prepared from either commercially available tablets dissolved in water or commercially available aqueous solutions. 5.2 Ethanol, 99 % (V/V) containing 1 % (V/V) water. 5.3 Water, conforming to Grade 3 of EN ISO 3696. EN 15490:2007 (E) 5 5.4 Lithium c
24、hloride solution, 1mol/l in 99 % (V/V) ethanol (5.2). 5.5 Sodium hydroxide aqueous solution, approximately 1 mol/l 5.6 Hydrochloric acid aqueous solution, approximately 1 mol/l 6 Apparatus 6.1 pH Meter, capable of reading to 0,01 pH with an accuracy of 0,01 pH (or 1 mV), preferably fitted with a tem
25、perature compensator. 6.2 Combined pH electrode, filled with a 1 mol/l solution of lithium chloride (LiCl) in 99 % (V/V) ethanol. 6.3 Magnetic stirrer 6.4 PTFE covered magnetic follower. 6.5 Glass beakers, approximately 100 ml capacity fitted with a cover to minimise the ingress of carbon dioxide fr
26、om the air. NOTE The cover should either be a rigid plastic cover with a hole to allow the electrode to pass through or a film of disposable plastic placed over the top of the beaker after the electrode has been inserted. 6.6 Timer, capable of measuring seconds. 7 Sampling and sample handling 7.1 Sa
27、mples shall be taken as described in EN ISO 3170. 7.2 Take care to minimise the uptake of atmospheric water during sampling and sample handling. NOTE The use of a glass bottle that can be sealed with a septum has been found suitable for sampling and sample handling. A test portion of the sample can
28、be taken through the septum with a syringe fitted with a needle. 8 Apparatus preparation 8.1 Clean/rehydrate new electrodes before use in alcoholic solutions and after measuring the pHe of 10 ethanol samples by alternatively soaking them in 1 mol/l sodium hydroxide solution (5.5) for approximately 3
29、0 s then 1 mol/l hydrochloric acid solution (5.6) for approximately 30 s. Repeat this procedure 3 times. 8.2 Wash the electrode free of acid and alkali with water (5.3) and allow draining. If the electrode is not to be used immediately, place in and store in a solution of lithium chloride in ethanol
30、 (5.4). 9 pH meter and electrode system calibration 9.1 Set up the pH meter in accordance with the manufactures instructions and, if fitted, adjust the temperature compensator to 22 C 2C. 9.2 Remove the combined electrode from the lithium chloride solution (5.4), wash with water (5.3) and allow drai
31、ning. 9.3 Rinse the combined electrode (6.2) with pH 4,00 buffer solution (5.1). EN 15490:2007 (E) 6 9.4 In a 100 ml beaker (6.5), place sufficient volume of pH 4,00 buffer solution (5.1) at 22 C 2C to cover the electrode. Insert the magnetic follower (6.6). 9.5 Place the beaker and its contents on
32、the magnetic stirrer (6.3). NOTE Automatic pH meters may require the user to input the pH value of the buffer solution. 9.6 Place the combined electrode (6.2) into the pH 4,00 buffer solution (5.1). Cover the beaker (see NOTE under 6.5). 9.7 Switch on the magnetic stirrer (6.3) and allow the pH mete
33、r reading to stabilize. 9.8 If necessary adjust the reading to 4,00. 9.9 Remove the combined electrode and rinse it with water (5.3). 9.10 Repeat 9.3 to 9.9 using the pH 10 buffer solution (5.1) (see NOTE under 9.5). If necessary, adjust the pH meter reading to 10,00 using the slope adjustment. 10 A
34、pparatus verification 10.1 Before testing each day and after cleaning/rehydrating the electrode, see clause 8, verify the correct functioning of the electrode/pH meter system using a pH 7,00 buffer solution (5.1) in accordance with 10.2 to 10.7. 10.2 Rinse the combined electrode with water (5.3) the
35、n with pH 7,00 buffer solution (5.1). 10.3 In a 100 ml beaker (6.5), place sufficient volume of pH 7,00 buffer solution (5.1) at 22 C 2C to cover the electrode. Insert the magnetic follower (6.4). 10.4 Place the beaker and its contents on the magnetic stirrer (6.3). 10.5 Place the combined electrode
36、 (6.2) into the pH 7,00 buffer solution (5.1), cover the beaker (see NOTE under 6.5). 10.6 Switch on the magnetic stirrer (6.3) and allow the pH meter reading to stabilize (see NOTE under 9.5). 10.7 The pH meter shall read pH 7,00 0,04. 10.8 If the reading is not within the tolerance in 10.7, remove
37、 the combined electrode, clean in accordance with 8.1 and repeat 10.1 to 10.6. 10.9 If the reading is still not within the tolerance in 10.7, recalibrate the electrode and pH meter in accordance with clause 9. 11 Procedure 11.1 If a temperature compensator is fitted to the pH meter, check and, if ne
38、cessary, adjust it to 22 C 2 C. 11.2 Bring the ethanol (5.2) to be tested to 22 C 2 C and place sufficient volume of it to cover the electrode in a 100 ml beaker (6.5). 11.3 Place the beaker and the test portion on a magnetic stirrer (6.3). Insert the magnetic follower (6.4) and the electrode and co
39、ver the beaker to minimise the ingress of atmospheric carbon dioxide. EN 15490:2007 (E) 7 11.4 Stir the test portion, allow the pHe reading to stabilize, see note. Record the pHe to the nearest 0,01. NOTE For some samples this may be in excess of 4 min. In such circumstances extra care should be tak
40、en to minimise the ingress of atmospheric carbon dioxide during the measurement. 12 Expression of results Report the pHe of the sample to the nearest 0,01. 13 Precision 13.1 General The precision given was derived from statistical analysis by EN ISO 4259 2 of the results of interlaboratory testing o
41、f a matrix of ethanol samples produced in Europe from bio materials such as raw wine, molasses, pulp and corn. Typical values are given in Table 1. NOTE The interlaboratory testing and the statistical evaluation are detailed in an UNGDA Report, September 2006 (UNGDA, 174 blvd Camlinat, 92247 MALAKOF
42、F Cedex, France, www.ungda.org). 13.2 Repeatability, r The difference between two test results, obtained by the same operator with the same apparatus under constant operating conditions on identical test material would in the long run, in the normal and correct operation of the test method, exceed t
43、he following value in only one case in twenty. r = 0,033 X (1) where X is the average of results being compared. 13.3 Reproducibility, R The difference between two single and independent results, obtained by different operators working in different laboratories on identical test material, would in t
44、he long run, in the normal and correct operation of the test method, exceed the following value only in one case in twenty. R = 0,096 X (2) where X is the average of results being compared. EN 15490:2007 (E) 8 Table 1 Calculated values for repeatability and reproducibility pHe Repeatability r Reprod
45、ucibility R 5 0,165 0,48 5,5 0,181 5 0,528 6 0,198 0,576 6,5 0,214 5 0,624 7 0,231 0,672 7,5 0,247 5 0,72 8 0,264 0,768 8,5 0,280 5 0,816 9 0,297 0,864 14 Test report The test report shall contain at least the following information: a) reference to this European Standard, i.e. EN 15490; b) type and
46、complete identification of the product tested; c) result of the test (see 12); d) any deviation, by agreement or otherwise, from the procedure specified; e) date of the test. EN 15490:2007 (E) 9 Annex A (informative) Background to actual fuel specification needs The test method described in this doc
47、ument is able to identify the presence (in fact the absence) of strong acids and alkalis in ethanol for fuel (blending) purposes. In general, ethanol for those purposes in Europe requires a minimum pHe of 6,5 and a maximum pHe of 9,0. This has been studied based on the methods reproducibility and it
48、 has been found unfit for compliance testing at the boundaries of the ethanol specification. The reason behind this is that the result is greatly influenced by the amount of water in the test sample. In general, the water content required in European fuels is rather low compared to similar specifica
49、tions in other regions of the world. The pH meter readings are not very stable and there can be a lot of reading drift caused by effects of the test sample on the glass electrode and possibly by take up of atmospheric carbon dioxide. Although guidance can be given on the length of time the operator waits until making the readings, laboratories reported that the time taken for their instrument varied and some laboratories reported that up to 4 minutes were required to obtain a stable reading. Having th
