CEN/TR 16885:2015
(Main)Liquid petroleum products - Investigation on test method for measurement of the oxidation stability of diesel and diesel/FAME blends by Acid Number after ageing
Liquid petroleum products - Investigation on test method for measurement of the oxidation stability of diesel and diesel/FAME blends by Acid Number after ageing
This Technical Report describes the investigation into the development of a standard test method to determine oxidation stability of diesel fuel and fatty acid methyl ester (FAME) blends in diesel by the use of determining the acid number after ageing at elevated temperature. It provides conclusions following this work that have been discussed by CEN. The result thereof is that no European Standard has been developed.
Flüssige Mineralöl-Erzeugnisse - Bericht über die Bestimmung der Oxidationsstabilität von Diesel und Diesel/FAME-Mischungen durch Bestimmung der Säurezahl nach Verälterung
Produits pétroliers liquides - Recherche de la détermination de la stabilité à l'oxydation du gazole et des mélanges gazole/EMAG par l'indice d'acide après vieillissement
Tekoči naftni proizvodi - Preiskovanje preskusne metode za merjenje oksidacijske stabilnosti dizla in FAME/dizelske mešanice s kislinskim številom po staranju
Ta dokument opisuje preiskovalno in preskusno metodo za merjenje oksidacijske stabilnosti dizelske mešanice FAME s kislinskim številom.
General Information
Standards Content (Sample)
SLOVENSKI STANDARD
01-december-2015
7HNRþLQDIWQLSURL]YRGL3UHLVNRYDQMHSUHVNXVQHPHWRGH]DPHUMHQMHRNVLGDFLMVNH
VWDELOQRVWLGL]ODLQ)$0(GL]HOVNHPHãDQLFHVNLVOLQVNLPãWHYLORPSRVWDUDQMX
Liquid petroleum products - Investigation on test method for measurement of the
oxidation stability of diesel and diesel/FAME blends by Acid Number after ageing
Flüssige Mineralöl-Erzeugnisse - Bericht über die Bestimmung der Oxidationsstabilität
von Diesel und Diesel/FAME-Mischungen durch Bestimmung der Säurezahl nach
Verälterung
Produits pétroliers liquides - Recherche de la détermination de la stabilité à l'oxydation
du gazole et des mélanges gazole/EMAG par l'indice d'acide après vieillissement
Ta slovenski standard je istoveten z: CEN/TR 16885:2015
ICS:
75.160.20 7HNRþDJRULYD Liquid fuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
CEN/TR 16885
TECHNICAL REPORT
RAPPORT TECHNIQUE
September 2015
TECHNISCHER BERICHT
ICS 75.160.20
English Version
Liquid petroleum products - Investigation on test method
for measurement of the oxidation stability of diesel and
diesel/FAME blends by Acid Number after ageing
Produits pétroliers liquides - Recherche de la Flüssige Mineralöl-Erzeugnisse - Bericht über die
détermination de la stabilité à l'oxydation du gazole et Bestimmung der Oxidationsstabilität von Diesel und
des mélanges gazole/EMAG par l'indice d'acide après Diesel/FAME-Mischungen durch Bestimmung der
vieillissement Säurezahl nach Verälterung
This Technical Report was approved by CEN on 17 August 2015. It has been drawn up by the Technical Committee CEN/TC 19.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, 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.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2015 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 16885:2015 E
worldwide for CEN national Members.
Contents Page
European foreword . 3
1 Scope . 4
2 Context and creation of a dedicated subgroup . 4
3 Participants in the work . 5
4 Meetings of the subgroup „Acid No.“ . 5
5 Main steps of the work item study . 6
5.1 Creation of the NWI . 6
5.2 Test method used . 6
5.3 First Round Robin Test . 7
5.4 Improvement of the test method . 7
5.5 Pass/fail methodology . 8
5.6 Second Round Robin Test . 9
6 Conclusions . 11
7 Acid number determination method available for lab use . 11
8 Acknowledgements . 11
Annex A (informative) Test method transcription . 12
Annex B (normative) Round Robin Results . 20
B.1 October 2010 results . 20
B.2 2012/2013 RRT . 22
Annex C (normative) Pass-/Fail discriminant analysis . 25
Bibliography . 31
European foreword
This document (CEN/TR 16885:2015) has been prepared by Technical Committee CEN/TC 19 “Gaseous and
liquid fuels, lubricants and related products of petroleum, synthetic and biological origin”, the secretariat of
which is held by NEN.
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.
1 Scope
This Technical Report describes the investigation into the development of a standard test method to
determine oxidation stability of diesel fuel and fatty acid methyl ester (FAME) blends in diesel by the use of
determining the acid number after ageing at elevated temperature. It provides conclusions following this
work that have been discussed by CEN. The result thereof is that no European Standard has been developed.
2 Context and creation of a dedicated subgroup
In case of poor diesel or biodiesel quality, ageing of the fuel in the fuel system under high pressure and
temperature (recirculation of fuel, high injector temperature, long storage in the vehicle fuel tank) may
cause various car problems due to the formation of acidity through oxidation (i.e. deposit of sediments,
deposit of lacquer, corrosion, lube oil deterioration).
Acidity of the fuel is therefore considered as a relevant parameter to evaluate oxidation stability of the Diesel
fuel. Test methods based on the measurement of the acid number (AN) after an ageing step were studied. An
ageing test temperature of 115 °C which is significantly higher than the test temperature of 95 °C applied in
EN ISO 12205 [1] has been chosen because it better discriminates fuel’s oxidation stability. Additionally, it is
closer to the temperature range prevailing in fuel systems of current and future engine technologies (i.e.
common rail systems).
Customer complaints related to fuel degradation linked to oxidation stability in France are shown in
Figure 1.
Figure 1 — Customer complaints linked to fuel degradation in France
A test method based on the change of the acid no. of a fuel during ageing, Delta AN, was evaluated in
CEN/TC 19/JWG1 'FAME Test methods' in 2008. In the Delta AN method, the fuel is aged at 115 °C for 16 h
by passing a stream of oxygen through the fuel using the oxidation cell of EN ISO 12205. The acid number of
the fuel before ageing is subtracted from the acid number of the aged fuel. The results of Round Robin tests
made on the Delta AN method led to the conclusion that the Delta AN test method, although discriminative,
exhibits a precision not enough robust ; this test method needed some analytical improvements. A draft
report about the test results applying the Delta AN method performed in 2008 was presented to
CEN/TC 19/JWG1 in January, 2011.
Further work concerning the improvement of the Delta AN test method was carried out in France in 2009. A
new test method based on the measurement of the acid number of the fuel after ageing was developed.
Based on the results of a cross check test, it was decided at the JWG1 meeting on September 4, 2009, that
additional work would be necessary concerning the robustness and precision of the new method. As such
work being not covered by the CEN/TC 19 mandate to JWG1, it was proposed that experts continue the
improvement work and issue a proposal for a NWI to WG 24.
Based on the results of the work of the French experts the continuation of the work was accepted by WG24
in March 2010. JWG1 started the work, creating a dedicated subgroup for this preliminary new work item
(PNWI).
3 Participants in the work
Several European experts were active within this project, represented by one or more member(s)
participating in the meetings. The memberships are listed in Table 1.
Table 1 — Members of the Subgroup „Acid No.“
Company Country Members
PSA France P. Jestin
S. Duperrier; P. Manuelli; P. Pestiaux; A.
TOTAL France
Vincent; A. Gandubert
SHELL M. Schmidt
Germany
Deutsche BP Germany W. Strojek
Neste Oil M. Kuronen
Finland
IFPEN L. Pidol
France
OMV Austria W. Koliander
ADM Germany J. Groos; J. Fischer
ASG Germany T. Wilharm
Metrohm Switzerland C. Haider; U. Loyall
SGS Germany, France M. Kulikowski; D. Juillet
4 Meetings of the subgroup „Acid No.“
The members of the group have been working on the assessment of the oxidation stability of diesel and
diesel/FAME blends by determination of the acid value after ageing from beginning of 2010 to mid-2014.
The meetings are listed in Table 2. This work have been reported and discussed within JWG1 at each session.
The main orientations and action plans have systematically been validated by JWG1.
Table 2 — Meetings of the Subgroup „Acid No.“
Meeting Date and location
Meeting 1 April 27, 2010
Conference call
Meeting 2 July 07, 2010
Meeting 3 January 14, 2011
Meeting 4 May 24, 2011
PSA Peugeot Citroën – Paris
Call conference July 25, 2011
Conference call
Meeting 5 September 02, 2011
IFPEN – Rueil
Meeting 6 March 22, 2012
PSA Peugeot Citroën – La Garenne Colombes
Meeting 7 November 13, 2013
TOTAL – Paris La Défense
5 Main steps of the work item study
5.1 Creation of the NWI
The first meeting of the group took place in April, 2010. The scope was presented to the members: the
objective was to improve the precision of the new acid number test method applicable to diesel fuels from
B0 to B10. In that context, some adjustments were made on the test method protocol and it was decided to
run first a cross-check test. Necessary improvements based on the outcome of the study should be
implemented to the method. A Round Robin test should finally be conducted in order to develop the
precision of the method.
5.2 Test method used
The method used has been developed to be applicable to diesel fuels from B0 to B10. The main analytical
parameters are listed hereafter and the full description of the test method is given in Annex A.
— Sample amount: (10 ± 0,2) g;
— Heating bath temperature: (115 ± 0,2) °C ;
— Oxygen rate: (1 ± 0,1) L/h;
— Running time for fuel oxidation: 16 h ± 5 min;
— Maximal time between the end of oxidation step and the AN measurement: 4 h.
The fuel was aged either in an oil bath or an heating bath as applied in the Rancimat equipment
5.3 First Round Robin Test
A RT was run in October, 2010 to assess the precision of the proposed new AN method on both colorimetric
and potentiometric determination of the AN. Nine samples were used for the RRT: 3 B0, 4 B7 and 2 B10.
Samples were representative for the European Market, some containing cetane improver (content between
100 and 1000 ppm), CFPP additives and/or lubricity additives. Thirteen labs out of fourteen participants
have returned their results on time: ten labs have performed colorimetric determination (oil bath and
[2]
Rancimat bath according to EN 15751 ) and eleven labs have performed potentiometric determination (oil
bath and Rancimat bath according to EN 15751). The results of this RRT are given in Annex B.
The RRT results led to the following comments:
— Even if there was a discrimination between “good” and “bad” products, results were worse than
expected, in particular for the potentiometric version. When the dispersion of results with the
potentiometric method was discussed, all participants agreed that experimental parameters were
perhaps not optimized and that it was necessary to work on it (electrode system, solvent, dynamic
titration, etc.).
— “Home-made” diesels, meaning diesels formulated by blending “good” and “bad” B0 or B7 in order to
reach certain AN target, seemed to have a strange behaviour. Even if the formulated products seemed to
be homogeneous, the results obtained by the labs were really different and the statistical distribution of
results indicated strong issues.
— There were some difficulties of being more precise on very good samples (AN <0,1 mg KOH/g). For non
acidic samples, the resulting precision is poor due to the precision of colorimetric titration (in test
method ISO 6618 [3] the reproduci
...
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