CEN/TR 17544:2020

SLOVENSKI STANDARD
01-december-2020
Goriva za motorna vozila - Poročilo o študijah o nagnjenosti k blokiranju filtra za
hladno vlaženje (CS-FBT) metilnega estra maščobnih kislin (FAME) kot mešanice
za dizelsko gorivo in o dizelskem gorivu, ki vsebuje do 30 % (V/V) FAME
Automotive fuels – Report on studies done on cold soak filter blocking tendency (CS-
FBT) on fatty acid methyl ester (FAME) as blend component for diesel fuel, and of diesel
fuel containing up to 30 % (V/V) of FAME
Kraftstoffe - Bericht über Studien zur cold soak filter blocking tendency (CS-FBT) an
Fettsäuremethylester (FAME) als Mischkomponente für Dieselkraftstoff und
Dieselkraftstoff, der bis zu 30% (V / V) FAME enthält
Carburants pour automobile Rapport sur les études relatives à la tendance au
colmatage de filtre après macération à froid dester méthylique dacides gras (EMAG)
comme composant pour le gazole et de gazole contenant jusquà 30% (V/V) dEMAG
Ta slovenski standard je istoveten z: CEN/TR 17544:2020
ICS:
75.160.20 Tekoča goriva Liquid fuels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17544
TECHNICAL REPORT
RAPPORT TECHNIQUE
September 2020
TECHNISCHER BERICHT
ICS 75.160.20
English Version
Automotive fuels - Report on studies done on cold soak
filter blocking tendency (CS-FBT) on fatty acid methyl
ester (FAME) as blend component for diesel fuel, and of
diesel fuel containing up to 30 % (V/V) of FAME
Carburants pour automobile - Rapport sur les études Kraftstoffe - Bericht über Studien zur cold soak filter
relatives à la tendance au colmatage de filtre après blocking tendency (CS-FBT) an Fettsäuremethylester
macération à froid d'ester méthylique d'acides gras (FAME) als Mischkomponente für Dieselkraftstoff und
(EMAG) comme composant pour le gazole et de gazole Dieselkraftstoff, der bis zu 30% (V / V) FAME enthält
contenant jusqu'à 30 % (V/V) d'EMAG

This Technical Report was approved by CEN on 7 September 2020. 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATIO N

EUROPÄISCHES KOMITEE FÜR NORMUN G

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17544:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 2
Introduction . 3
1 Scope . 4
2 Normative references . 4
3 Terms and definitions . 4
4 Filter blocking tendency of diesel fuels and FAME . 4
4.1 Evolution of diesel fuels and FAME composition . 4
4.2 Detail of field issues . 5
4.3 FBT test development . 5
5 CS-FBT studies . 5
5.1 General . 5
5.2 Ruggedness studies – 2011 - 2013. 6
5.3 Studies on parameter impacts . 11
5.4 Comparison FAME data vs results with CS-FBT . 14
6 Comparison of CS-FBT with C-FBT . 16
6.1 General . 16
6.2 Comparison study CS-FBT/C-FBT– 2017 . 16
7 Conclusion and perspectives on filter blocking tendency . 18
Annex A (informative) Description of the different methods . 19
Annex B (informative) Ruggedness study 2011– detailed results . 20
B.1 Overview of mini ILS . 20
B.2 Overview of the results set . 21
B.3 Overview of the statistical analysis . 21
Annex C (normative) Working draft . 24
Annex D (informative) Ruggedness study 2013– detailed results . 31
D.1 Preliminary works . 31
D.2 Ruggedness study 2013 . 31
D.3 Results assessment . 34
Annex E (informative) CS-FBT for FAME – detailed results . 37
Bibliography . 38

European foreword
This document (CEN/TR 17544:2020) 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 shall not be held responsible for identifying any or all such patent rights.
Introduction
[1]
As reported in CEN/TR 16982 , during recent past winters, a wide range of vehicles has been affected in
specific European countries and there are possible links with fatty acid methyl esters (FAME)
composition, base diesel quality, cold flow additives and oxidation stability effects. In order to solve these
issues, some countries have introduced new additional requirements in their national specifications or
“best practice” market agreements.
In the UK, developments around the Filter Blocking Tendency test (FBT) has been engaged and in
[2]
particular a variant of the IP 387 with a Cold Soak step (CS-FBT). This work has been exchanged with
CEN/TC19 and the CEN/TC19/WG31 has started several studies in order to evaluate the interest of using
this method for neat FAME and diesel fuels containing up to 30 % (V/V) of FAME.
This document reports the content of these studies.
1 Scope
This document describes the studies executed to develop a method to analyse the filter blocking tendency
after a cold soak step of fatty acid methyl ester (FAME) as a blend component for diesel and of diesel fuel
containing up to 30 % (V/V) of FAME, respectively.
NOTE For the purposes of this document, the term “% (V/V)” is used to represent the volume fraction, φ.
2 Normative references
There are no normative references in this document.
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http://www.iso.org/obp
— IEC Electropedia: available at https://www.electropedia.org/
3.1
filter blocking tendency
FBT
dimensionless value that defines the filter blocking tendency of a fuel caused by particulates
Note 1 to entry: The value is calculated using the pressure or volume attained at the end of the test. Depending on
[2]
the outcome of the test, two different equations are applied (see IP 387 , Clause 9 for the calculation of the FBT
value).
[SOURCE: IP 387]
3.2
cold soak
CS
exposure of the test portion to a constant reduced temperature for a period of time
[3]
[SOURCE: IP PM-EA ]
3.3
cold soak filter blocking tendency
CS-FBT
variant of an FBT determination which includes a cold soak step before testing the sample
4 Filter blocking tendency of diesel fuels and FAME
4.1 Evolution of diesel fuels and FAME composition
In recent years diesel fuels have become more complex as FAME, hydrotreated vegetable oils (HVO), Gas-
To-Liquid (GTL), etc. have been increasingly introduced into diesel blends. FAME has evolved from its
origins as RME (Rapeseed Methyl Ester) into a wide variety of sources including animal sourced (TME -
Tallow Methyl Ester) and used cooking oil (UCOME – Used Cooking Oil Methyl Ester). These changes to
fuel composition are considered to have a possible impact to the Filter Blocking Tendency of the fuel.
4.2 Detail of field issues
The detail of field issues in different areas in Europe are well documented in CEN/TR 16982. This report
includes also several works engaged in different countries to understand those field issues among which
[4]
the development of FBT test and variants including the CS-FBT and the Cold FBT (C-FBT, IP 618 ).
4.3 FBT test development
[5] [6]
As described in CEN/TR 16884 , the FBT test (IP 387, ASTM D2068 ) was originally developed as the
“Navy Rig Test” in the 1980s by the UK Ministry of Defence (National Gas Turbine Establishment) to
predict operability of warships after the Falklands War. Warship filters were being blocked by rust, sand,
microbiological growth and insoluble gums, and a need was identified to develop a lab test with a direct
correlation to filter blocking of filter/coalescer elements. The test was later standardized as IP 387
following a Ministry of Defence request to establish test precision. The NATO F-76 naval distillate fuel
specification contains a requirement for FBT, and in Australia and New Zealand, legislation requires that
diesel fuel shall meet a maximum FBT limit.
Today, the FBT test is used to determine the filterability of middle distillate fuels, biofuels such as FAME
and diesel / biofuel blends. This method is not necessarily a cold flow test, however it has been found to
be effective at detecting poorly blended MDFI additives and is sensitive to a number of other solid
contaminants that can be found in modern diesel fuels. The filter pore size is also representative of
modern diesel vehicle fuel filter technology.
For the Filter Blocking Tendency Test, a 300 ml sample portion of the fuel is passed at a constant flow
rate of 20 ml/min through a specified filter medium. There are several different procedures contained
within the FBT test method. In Procedures A and B a 13 mm diameter, 1,6 µm glass fibre filter is used;
whereas in Procedure C a 22 mm diameter, 5 µm nylon filter is used. The pressure difference across the
filter and the volume of fuel passing through the filter are monitored until the pressure reaches 105 kPa
or the volume of fuel passing through the filter medium reaches 300 ml, at which point the test is
terminated.
[7] [8] [9]
Cold flow tests such as Cloud Point (CP) , Cold Filter Plugging Point (CFPP) and Pour Point (PP) are
designed to detect and test the impact of paraffin wax deposition once a distillate fuel reaches and drops
below its cloud point. The field issues mentioned in 4.2 were encountered at temperatures above the CP
of the fuel.
The FBT test was developed to detect potential filter blocking above the cloud point of the fuel. It’s
important to note that it should not be used at, or below, the cloud point.
5 CS-FBT studies
5.1 General
[3]
The CS-FBT is a variant of FBT test developed by Energy Institute (IP PM-EA ). The CS-FBT test adopts
a low temperature sample pre-conditioning step which involves cold soaking the fuel sample for 16 h to
accelerate the precipitation of the insoluble impurities, before allowing the fuel to warm to ambient
temperature and performing a filtration step identical to the FBT test. By allowing the sample to warm to
ambient temperature after the cold soak, the test only measures those impurities that do not re-dissolve
easily after they have formed.
Using the FBT test only may not detect impurities such as saturated monoglycerides (SMG) and sterol
glucosides (SG) which only manifest themselves at lower temperatures, but above the cloud point of the
fuel. Therefore, a “cold” version of IP 387 was investigated to detect these impurities which can
precipitate out of the fuel above its cloud point.
This type of approach has been studied in northern America. In Canada, the CGSB (Canadian General
[10]
Standards Board) has already developed its own CS-FBT test method (CGSB-3.0 – No 142.0 ) that is also
[11]
based on the FBT test. This test has been adopted in the CGSB 3.524 specification for FAME. In the USA,
[12]
the Cold Soak Filtration Test (ASTM D7501 ) has also been developed and is required in the ASTM
[13]
specification for FAME (ASTM D6751 ).
NOTE Details of the different methods can be found in Table A.1.
5.2 Ruggedness studies – 2011 - 2013
5.2.1 Ruggedness study 2011
5.2.1.1 Origin
A joint meeting with CEN/TC 19/WG 31 and Energy Institute was held in London on February 1st 2011 as
a “Cold Filterability Workshop”.
Plans were discussed to organize a ruggedness study. The study procedure was defined in June 2011 and
testing to be carried out in September 2011 with results to be available for WG24 meeting in
November 2011.
The mini ILS test on CS-FBT method was carried out in September 2011:
— ten FAME samples tested by 8 laboratories using the method developed by CEN/TC 19/WG 31 (main
parameters presented in Table 1),
[14]
— Each FAME sample tested as a B10 blend in a EN 590 compliant fuel (GO PSA4 blanc) and de-
aromatized kerosene as described in the IP PM-EA test, hereafter:
— A FAME sample is treated to delete its thermal history by keeping it at elevated temperature
(60 °C) for (2 – 3) hours and then allowing to cool to room temperature. Then, it is blended as
B10 and it is cooled to 5 °C, kept at this temperature for 16 h and again allowed to reach room
temperature (see Figure 1). The objective of this process is to favour the precipitation of any
compounds that can cause filtration problems.
— The appearance of the sample is then evaluated.
— The filter blocking tendency (FBT according to IP 387-procedure B) is determined by passing a
constant flow of the prepared sample through a specific filter.
— The FBT value and the appearance of the sample (AR) (see Table B.2) are used to calculate the
Filterability Factor (FF) (see Formula (B.1)) which determines the acceptability of the sample.
— Testing was carried out in duplicate.
NOTE Details for this Ruggedness study 2011 can be found in Annex B

Figure 1 — Sample preparation scheme
Table 1 — Ruggedness studies, procedure details
Parameter Ruggedness Study 2011 Ruggedness Study 2013
Glassware Glassware not defined Unscratched Glassware for FBT
FAME sample Yes (shaking for 30s) Yes (shaking for 30s)
homogenization
FAME heating 60 °C ± 2 °C for 120 min ± 10 min 60 °C ± 2 °C for 120 min ± 10 min
FAME cooling At ambient T in air or water bath At ambient T in air
Mixing with Stirring during 1min Shaking approx. 2min
DAK
Cold Soak 16h@5 °C, cooling chamber or 16h@5 °C, cooling chamber
water bath
Warming-up 20 °C ± 5 °C for a period no longer 20 °C ± 5 °C for a period no longer
than 2 h in air or water batch than 2 h in air
Homogenization Stir the sample vigorously, using a shake 5 min, allow to stand for 2
magnetic stirrer, for 120 s ± 5s, min
and allow to stand for 300 s
Beaker Keep in same beaker for FBT test Transfer to FBT beaker
(unscratched)
5.2.1.2 Outcome
Main results following the 2011 study are:
— Evaluation using FBT discriminated between good and bad samples but 2R limit not reached,
— Evaluation on volume gave even better discriminated between good and bad samples,
— All test conditions (for both solvents) in general gave comparable results,
— However, precision remained an issue when comparing results from different laboratories; sample
homogeneity or sample preparation (B10 blending) may be a reason.
Main outcomes are:
— New project group set up to optimize the precision of proposed IP PM-EA test,
— Detailed investigation of sample preparation and filtration,
— Work on calibration for FBT methods and explore reasons for test variability. Explore opportunities
for developing a suitable calibration material for “higher” FBT values,
— Work on modifications of the method (e.g. stirring during filtration).
5.2.2 Ruggedness study 2013
5.2.2.1 Origin
At the 18th meeting of WG 31 (7th February 2013), the group felt that the main issue with the original
ruggedness test was poor precision and the correlation with field filterability issues.
NOTE The details of Ruggedness study 2013 are given in Annex D.
5.2.2.2 Preliminary testing
It was reported that preliminary tests were carried out with 2 FBT verification fluids to understand if
such fluids can be used in future ILS to check the validity of the IP 387 FBT apparatus. The fluids were
EN 590 diesel products with a contaminant added: two samples with FBT of approx. 2,5 and two others
with FBT of approx. 5,0 and Type B filters were supplied to the seven laboratories taking part in the study
(see Table D.1).
A detailed sample preparation procedure was provided to the participants as well (samples are shaken
for 120 s and then allowed to stand for 5 min in order to simulate real life, i.e. let large particles drop
down to the bottom).
a) b)
Figure 2 — Main results of preliminary testing
Main results of the pre-study were (see Figure 2):
— The results were overall encouraging.
— Reproducible results can be obtained on the same sample. Deviations found for some laboratories
may have been due to technical reasons.
— It was concluded that it would be appropriate to have a verification material for future ILS.
Proposals discussed to improve precision in the group were then:
— Stirring,
— Evaluation of pressure curves,
— Cooling rate,
— Container material – Feedback from one Lab mentioned some influence on FBT,
— Grounding of IP 387 apparatus – Canadian work on CS-FBT showed that grounding has an influence,
— More defined sample preparation – Possible reason for poor results in the 2011 ruggedness study.
5.2.2.3 Ruggedness study 1
The scope of the new ruggedness study was defined to identify if proposed modifications of the method
were successful and to give preliminary evaluation of the test precision.
The set-up of the study was defined as follows:
— a new draft method has been defined referenced as WG 24/N403 (see right column in Table 1),
— Method has two parts for testing FAME and diesel,
— Procedure A – For testing of FAME as B10 in de-aromatized kerosene,
— Procedure B – For testing of finished diesel fuels.
— four laboratories,
— three FAME samples for Method A testing,
— three B10 finished blends (using the same FAME samples) for Method B testing.
Protocol used:
— Three different types of preparation were requested on the samples to the laboratories:
— With FAME samples received: Prepare two different B10 blends as per procedure A,
— With FAME samples received: Prepare 0,8 l of one B10 sample, but separate the samples before
cold soak, carry out the rest of the procedure A 2 times,
— With two B10 samples per FAME as received: carry out procedure B.
a) b)
c)
Figure 3 — Effect of B10 preparation
Results of the first study:
— Procedure A – Precision still an issue especially for higher FBT values – Inter laboratory precision
needs improvement. Sample preparation (blending of FAME) is an important step (see Figures 3.a
and 3.b),
— Procedure B – Much better results in terms of estimated precision of the method (see Figure 3.c). No
sample preparation.
5.2.2.4 Ruggedness study 2
Based on the work in 2013, WG 31 concluded that it seemed necessary to modify the test conditions, e.g.
sample size to be able to reach 60°C. The experts decided to run new trial, aiming to give results by mid-
2014.
Details of the new trial using eight laboratories:
— Using Procedure A (FAME and de-aromatized kerosene)
— four FAME samples
— three experiments:
— Experiment 1 – CS-FBT within 1 h of blending
— Experiment 2 - Heat soak for 1 h at 60°C before CS-FBT
— Experiment 3 - 24 h delay before CS-FBT
— Using Procedure B (finished diesel)
— One diesel sample
15]
— Optional ASTM D2709[ centrifuge test

a) b)
Figure 4 — Results of 2014 trial
At the 21st meeting of WG 31 on 10 September 2014, results of the new trial were presented (see
Figure 4):
— For FAME (Procedure A) the average results are similar:
— Experiment conditions did not affect the overall mean of each sample;
— Standard deviations are different for each sample and each experiment.
— For the finished fuel (Procedure B):
— The precision is significantly better and similar to IP 387 (see Table D.4);
— The results of the ASTM D2709 centrifuge test did not provide further useful data (see
Table D.6).
This resulted in a further proposal to carry out another ILS with a reference diesel instead of DAK (de-
aromatized kerosene), as DAK seems to be too severe.
5.3 Studies on parameter impacts
5.3.1 General
The CS-FBT ruggedness study ran in 2013/14 (see 5.2) led to poor results for FAME (Procedure A). Two
assumptions were then proposed:
— either the laboratories had difficulty making volumetric solutions (which is unlikely),
— or the samples were tampered during their air transportation/over the course of the study
(preferred option).
In this framework, it was decided to carry out further tests in the 2015-2017 time frame in one laboratory
to determine whether it is preferable to send pure FAME or pre-blended samples with DAK to
laboratories willing to participate in the CS-FBT ILS.
5.3.2 Samples
The six FAME samples used for this complementary study are listed in Table 2. All these FAME were
provided by a single supplier.
Table 2 — FAME identification and their corresponding descriptions
FAME reference FAME description
410–254 Undistilled RME/(PME; Sunflower ME) blend (60:40)
410–255 Undistilled RME/PME blend (95:5)
410–256 Pure undistilled RME
410–257 Pure distilled TME
410–258 Pure undistilled UCOME
410–259 Pure distilled RME
NOTE To monitor the FAME thermal history, FAME were transported, immediately manufactured, under the
same temperature conditions by road from the plant to the testing laboratory.
The diluent, shown in the Table 3 was used for tests. This was used as the low aromatic kerosene (see
C.6.2).
Table 3 — Diluent identification and its corresponding description
Diluent reference Diluent description
DAK 286735Q De-Aromatized Kerosene (DAK) from VWR (CAS n°64742–47–8)
Prior to use DAK was filtered on a cellulose filter (0.45 µm)
5.3.3 Apparatus
The Stanhope-Seta MFT apparatus with serial number 1038958 was used. The instrument was calibrated
prior testing in accordance with the manufacturer’s instructions. Filters in glass fibre were used as per
the test method.
5.3.4 Sample preparation
5.3.4.1 General preparation
Samples were prepared following to two different procedures: with and without freezing prior to the
application of the CS-FBT method described in Annex C.
NOTE To mimic sample freezing that can occur during air transportation, Air France and Aéroports de Paris
were questioned about temperature during transportation. They answered that depending on the destination and
airline, temperatures ranging from – 20 °C to 10 °C can be encountered in cargo planes. That is why these two
temperatures were studied.
5.3.4.2 Procedure with freezing at −20 °C or chilling at 10 °C
Description of the procedure used:
— Shake FAME sample vigorously for 30 s;
— Freeze or chill the FAME sample in an environmental chamber at −20 °C or 10 °C for 48 h;
— Remove from the environmental chamber and leave it to room temperature for 24 h;
— Place whole FAME sample in oven at 60 °C for 120 min;
— Remove from oven and allow to cool to 20 °C within 120 min;
— Shake FAME sample vigorously for 30 s (allow air bubbles to disperse);
— Apply directly the CS-FBT method described in C.12 on FAME and B10.
NOTE To prepare 10 % (V/V) blends, 50 ml of FAME and 450 ml of diluent were added to a 1 L clean bottle.
Bottles were then shaken for 2 min.
5.3.4.3 Description of the procedure without freezing or chilling
Description of the procedure used:
— Shake FAME sample vigorously for 30 s;
— Place whole FAME sample in oven at 60 °C for 120 min;
— Remove from oven and allowed to cool to 20 °C within 120 min;
— Shake FAME sample vigorously for 30 s (allowed air bubbles to disperse);
— Apply the CS-FBT method described in C.12 on FAME and B10.
5.3.5 Results
Table 4 presents the results of the complementary trials.
Table 4 — FAME CS-Filter Blocking Tendencies including FAME dilution and freezing steps
Pure FAME B10
FAME Ref. Without Chilling Freezing Without Chilling Freezing
freezing @ 10 °C @ −20 °C freezing @ 10 °C @ −20 °C
410–254 12,54 10,56 4,45 1,28 1,35 1,13
410–255 8,06 4,37 1,30 1,39 1,28 1,09
a a
410–256 4,68 n.m. 4,40 1,23 n.m. 1,10
a a a a
410–257 3,05 n.m. n.m. 1,00 n.m. n.m.
410–258 30,01 15,56 30,01 1,29 4,29 1,04
a a
410–259 1,22 n.m. 1,15 1,01 n.m. 1,01
a
n.m. is for not measured
NOTE 1 The results in Table 4 are average results, detailed results are reported in Table E.1.
NOTE 2 Contrary to what was intended (see 5.3.1), the WG studied the temperature impact on FAME and not on
B10 samples. Freezing and chilling steps were always performed on pure FAME. This means that the impact of
temperature on pre-blended samples with DAK was not studied as such.
According to Table 4, the following was observed:
— CS-FBT results for pure UCOME (410-258) are very high because it plugs immediately the filter and
this happened whatever the freezing applied or not;
— As expected, the distillation step impacts the CS-FBT results whatever the freezing applied or not.
Distilled RME (410 - 259) has a far better CS-FBT result than undistilled RME sample (420 - 256);
— As expected, CS-FBT results of pure FAME are higher than those obtained with B10. The DAK dilution
allowed to dilute impurities/contaminants and thus eased the flow. Moreover, on pure FAME, poor
repeatability is observed;
— Globally, when decreasing the temperature prior to filterability measurement, the CS-FBT decreases.
The differences of the results are significant regarding the repeatability of the IP 387. Freezing
impacts thus slightly the CS-FBT results;
— On diluted samples (B10), FAME discrimination is not easy due to the narrow distribution. It will be
thus difficult to carry out an ILS on B10 if, despite different samples, little variability is observed.
5.3.6 Complementary testing
To go further, complementary tests were performed to study the impact of the cold-soak step on the
filterability results. The same blended samples (B10) – prepared according to the procedure without
freezing – were tested according to the FBT method (IP 387).
Results were compared to those obtained when CS-FBT is applied (Table 5).
Given the fact that only one FBT measurement was performed and the poor reproducibility of the method,
we cannot draw easily conclusions but only tendencies. However, results suggest that the cold-soak step
at 5 °C does not significantly impact the filterability results.
CS-FBT method does not seem to be better than FBT method whereas this method is longer to carry out.
Table 5 — Comparison FBT vs. CS-FBT of B10 samples
Results in the
B10 (FAME Ref) FBT values CS-FBT values reproducibility of the
method
B10 (410–254) 1,17 1,28 Yes
B10 (410–255) 1,74 1,39 No
B10 (410–256) 1,28 1,23 Yes
B10 (410–257) 1,00 1,00 Yes
B10 (410–258) 1,10 1,29 No
B10 (410–259) 1,01 1,01 Yes
5.4 Comparison FAME data vs results with CS-FBT
In this part, the impurities (glycerol, SMG and sterylglucosides) of FAME samples listed in Table 2 were
determined. The objective was to see if a correlation between impurities and the CS-FBT results obtained
on the B10 could be identified.
Impurities of FAME samples are gathered in Table 6.
Table 6 — Properties of FAME samples
unit Method 410– 410– 410– 410– 410– 410–
Characteristics
254 255 256 257 258 259
Density kg/m EN ISO 12185 882,3 883,0 883,5 874,7 887,1 882,7
a
Cloud point °C EN 23015 −3,4 −4 −3,7 14 n.m. −4,5
g/100g
Free glycerol EN 14105 0,020 0,050 0,030 0,030 0,005 0,060
(% (m/m))
g/100g
Mono glycerides EN 14105 0,58 0,72 0,74 0,25 0,46 0,49
(% (m/m))
g/100g
Diglycerides EN 14105 0,13 0,21 0,23 0,05 0,23 0,05
(% (m/m))
g/100g
Triglycerides EN 14105 < 0,05 < 0,05 0,05 0,05 0,19 < 0,05
(% (m/m))
g/100g
Total glycerol EN 14105 0,19 0,27 0,26 0,03 0,17 0,19
(% (m/m))
Sterylglucosides mg/kg EN 16934 37 39 21 1 5 2
Saturated mono
mg/kg EN 17057 700 600 400 < 50 1 000 400
glycerides
“FBT expected”
according to  Level 3 3 2 1 2 1
impurities
CS-FBT on B10
Annex C 1,28 1,39 1,23 1,00 1,29 1,01
blends
a
n.m. is for not measured (sample too dark)
According to Table 6, it was observed that:
— Sterylglucosides and SMG levels of FAME samples vary between (1 – 39) mg/kg and
(50 – 1 000) mg/kg respectively and mean values are 17 mg/kg and 525 mg/kg respectively;
— The levels of “FBT expected” were determined considering the following assumptions:
— if sterylglucosides and SMG contents are below average (i.e. low impurities),
➢ Assumption of low clogging tendency (Level 1);
— if the levels of sterylglucosides and SMG are one lower and the other higher than their means
(i.e. intermediate impurities content),
➢ Assumption of an average tendency to clogging (Level 2);
— if sterylglucosides and SMG contents are above average (i.e. high impurities),
➢ Assumption of a high clogging tendency (Level 3);
— Distilled FAME (410-257 and 410-259) with low impurity levels and thus a low “FBT expected” have
a low CS-FBT;
— FAME with the highest impurity contents which could therefore suggest a significant clogging trend
have the highest CS-FBT.
Globally, on the six FAMEs tested, we have a good correlation between the amount of impurities and the
CS-FBT results obtained with B10 blends.
6 Comparison of CS-FBT with C-FBT
6.1 General
[4]
The UK Energy Institute has developed the method IP 618 (C-FBT) for measuring the cold filter blocking
tendency at +3 °C and −1 °C, in order to simulate typical winter operating temperatures.
The C-FBT is a performance based diesel fuel test which is intended to highlight potential filtration issues
such as poorly blended cold flow additive, low level polyethylene, saturated mono glycerides, sterol
glucosides and water, or in some cases ineffective additive chemistry to deal with the challenging cold
winter conditions even for non-biodiesel distillate fuels.
6.2 Comparison study CS-FBT/C-FBT– 2017
6.2.1 General
Since the development in 2017 of IP 618, new test method which allows to control the temperature
during the filtration step, it was decided to compare CS-FBT results to C-FBT.
Note: Due to low availability of C-FBT equipment, C-FBT measurements were performed at the
Stanhope-Seta facility. To limit the FAME ageing, FAME were transported by road from the testing
laboratory to the Stanhope-Seta facility located in the London area.
6.2.2 Samples
The six FAME samples used previously (Table 2) were used to compare CS-FBT and C-FBT methods.
The diluent, shown in Table 7 was used for tests performed at Stanhope-Seta facility. It was used as low
aromatic kerosene similar to that specified in C.6.2.
Table 7 — Diluent identification and its corresponding description
Diluent reference Diluent description
VWR Heavy Distillate for cold soak project
SA 1744
Prior to use diluent was filtered on a cellulose filter (0,80 µm)
6.2.3 Apparatus
The Stanhope-Seta C-FBT apparatus with serial number 1039588 was used. The instrument was
calibrated prior testing in accordance with the manufacturer’s instructions. IP 618 filters were used as
per the test method. They were enclosed in an aluminium housing which allows filters to reach
temperature effectively.
6.2.4 Sample preparation
Samples were prepared in accordance with Annex C:
— Shake FAME sample vigorously for 30 s;
— Place whole FAME sample in oven at 60 °C for 120 min;
— Remove from oven and allow to cool to 20 °C within 120 min;
— Shake FAME sample vigorously for 30 s (allow air bubbles to disperse);
— Blend FAME and diluent using 250 ml measuring cylinder and 20 mL pipette:
— Add 40 mL of FAME and 360 ml of diluent to a 1 L clean bottle for 10 % (V/V) blend;
— Add120 mL of FAME and 280 ml of diluent to a 1 L clean bottle for 30 % (V/V) blend;
— Shake bottle for 2 min;
— Apply the C-FBT method described in IP 618.
6.2.5 Results
Table 8 shows the results of the comparison.
Table 8 — Comparison CS-FBT vs C-FBT results
Blends B10 B30
CS-FBT CS-FBT
C-FBT C-FBT C-FBT
FAME Ref. (CS @ 5 °C and (CS @ 5 °C and
(Test @ 10 °C) (Test @ 3 °C) (Test @ 10 °C)
Test @ 20 °C) Test @ 20 °C)
a
410–254 1,28 2,51 n.m. 7,56 6,08
a
410–255 1,39 1,08 n.m. 5,09 5,09
410–256 1,23 1,80 2,25 2,69 2,51
410–257 1,00 1,02 1,01 2,90 1,15
b
410–258 1,29 DNF 1,27 30,01 30,01
a
410–259 1,01 1,00 n.m. 1,03 1,01
a
n.m. is for “not measured”
b
DNF is for “Did not filter at all”
According to Table 8, we observe that:
— Depending on the dilution or the temperature of test, it was hard to determine the C-FBT of UCOME
sample (410-258);
— With the C-FBT method, a larger distribution of results is observed:
— For B10 samples, we have a range of C-FBT from 1,00 to 2,51 (comparing to 1,00 to 1,39 with CS-
FBT);
— For B30 samples, we have a range of C-FBT from 1,15 to 30,01 (comparing to 1,01 to 2,25 with
CS-FBT);
— The temperature at which C-FBT is performed seems to play a key role in the filterability results:
results at 3°C are higher or similar than those obtained at 10°C. This factor is of interest if an ILS is
triggered; it would help to differentiate FAME and could help to extend the application scope;
— Given this last observation, it is difficult to compare C-FBT and CS-FBT methods. Indeed, C-FBT is
measured directly at a fixed cold temperature (3 °C or 10 °C) whereas CS-FBT is measured at room
temperature (around 20 °C).
7 Conclusion and perspectives on filter blocking tendency
The Cold Soak FBT method, IP PM-EA/08, was introduced to assess the filter blocking tendency of neat
FAME using a 10 % dilution of FAME in low aromatic kerosene (B10); but no precision data had been
determined.
The study carried out in 2011 by WG31, using a method based on IP PM-EA/08, showed that precision
was an issue when comparing results from different laboratories. The test method differed from
IP PM - EA/08 in that an EN 590 compliant fuel was also used along with the de-aromatized kerosene
(DAK) similar to that used in IP PM-EA/08.
Additional ruggedness tests were carried out in 2013 using a new draft method WG24/N403.
Modifications were made to tighten up the procedure including taking special care to use unscratched
glassware. The main modification was a change in the scope to include the testing of fuels prepared at
one location which were then distributed to each laboratory (Finished fuels - Method B). Precision
remained poor between laboratories when preparing blends (Method A) but much better when testing
the finished fuels (Method B).
IP PM-EA/13 was published, as an update to IP PM-EA/08, to include both Method A and Method B
(Precision not yet determined).
Further experiments using WG24/N403 but with modifications to Method A (CS-FBT carried out at
different intervals after B10 blending and heating of the B10) did not significantly improve the precision
of Method A.
The thermal history of the FAME samples during shipment was considered to be the most likely reason
for the poor precision. It was considered unlikely that individual laboratories would have difficulties
making the B10 blends.
Testing FAME samples that had been frozen, and then heated, indicated that thermal history can impact
the CS-FBT results.
In conclusion, the CS-FBT appears suitable for testing finished fuels containing FAME (Method B of
WG24/N403) but is not robust for testing of neat FAME (as a 10 % dilution in DAK).
The Energy Institute has since published IP 618 which utilizes a Cold FBT (C-FBT) rather than CS-FBT.
The scope of IP 618 (Cold FBT) only includes finished fuels containing up to 20 % of FAME. Comparisons
done in 2017 between the two methods CS-FBT and C-FBT on same set of samples have not allowed us
to conclude on behaviour.
The follow-up of work ongoing at Energy Institute on Cold FBT method is to allow us to find a better way
to assess the filtering issue with FAME.
Annex A
(informative)
Description of the different methods
Table A.1 gives the details of the different methods mentioned in this document as variant of FBT.
Table A.1 — Different test methods as variant of FBT
ASTM D7501-18a – CGSB-3.0 (No IP PM-EA –
Methods
IP 387 – FBT IP 618 –
Cold Soak Filtration 142.0) Cold Cold Soak
(ASTM D2068-17) Cold FBT
[13]
Test Soak FBT FBT
Middle Distillate Biodiesel (B100) Biodiesel FAME Middle
Scope
fuels (B0), and with cloud point (B100) (B100 as Distillate
fuels such as below 20 °C 10 % in LAK) containing
Biodiesel (B100) and Diesel up to 20 %
and Biodiesel Fuels FAME
blends (Bx) containing up
to 30 % FAME
Sample
preparation FAME 0 to 100 100 20 10 0 to 20
content (%V/V)
Low Aromatic
Diluent
None None Isopar L Kerosene None
(LAK)
FAME
Not
conditioning Not applicable 40 60 60
applicable
Temperature (°C)
Soak
Not applicable 4,5 1 5 Optional, 5
Temperature (°C)
Soak Time (h) Not applicable 16 16 16 Optional, 16
Test Temperature
15 to 25 24,5 to 25,5 24 to 26 18 to 22 3 and −1
(°C)
Filter porosity
1,6 (GF/A) 0,7 (GF/F) 1,6 (GF/A) 1,6 (GF/A) 1,6 (GF/A)
(µm)
Filter Diameter
1,3 4,7 1,3 1,3 1,3
(cm)
Test Time (min) 15 max 12 max 15 max 15 max 15 max
Test Volume (ml) 300 300 300 300 300
360 s max (200 s
Pass/Fail Limit
max for application
below −12 °C)
Annex B
(informative)
Ruggedness study 2011– detailed results
B.1 Overview of mini ILS
— Participants (8 Laboratories): Repsol, Shell, BP, Total, Cargill, Infineum, ASG, Q8
— 10 FAME Samples (see Table B.1)
— Procedure based on IP PM/EA modified
— Organization / completion of draft done by L. Arrabal-Flores, T. Kweekel, A. Galonzelli, W. Strojek
— Sample Distribution by IFTS after homogenization of FAMEs
— Compositional Data by H. Stein / ASG Germany
— Solvents for preparation of B10 blends:
— DAK from IP PM EA
— B0: fuel “GO PSA 4 Blanc” w/o additives, low CP/CFPP, EN 590 compliant, Typical in aromatics
Table B.1 — FAME samples
Sample N° FAME type description
FBT_FAME_1 Pure SME untreated on SG
FBT_FAME_2 SME/high PME blend
FBT_FAME_3 PME/SME commercial
FBT_FAME_4 Commercial FAME “intermediate”
FBT_FAME_5 Good, commercial FAME
FBT_FAME_6 Distilled AFME
FBT_FAME_7 20 PME / 80 SME
FBT_FAME_8 70 PME / 30 SME
FBT_FAME_9 50 PME / 50 SME
FBT_FAME_10 Undistilled PME
B.2 Overview of the results set
— 2 sets of results were obtained:
— Dilution in DAK ➔ FBT
— Dilution in GO PSA 4 ➔ FBT
— For both solvents, the appearance rating before FBT testing was recorded as well in a separate
evaluation.
Here below details for appearance rating (AR) and filtration factor (FF) from the procedure applied:
Table B.2 — Appearance rating (AR)
Appearance
Description
rating (AR)
Clear and bright. Absence of turbidity (do not take into account small dirt
particles). Absence of floating layer at the top of the sample.
Slightly hazy, and/or small particles either in suspension or as a
0,5 precipitate (do not take into account small dirt particles). Absence of
floating layer at the top of the sample.
Hazy, particles suspended or precipitated (do not take into account small
dirt particles) and/or a floating layer at the top of the sample is detected.
Extremely hazy, particles suspended, precipitated or on the walls
covering more than 75 % of the volume of the sample (do not take into
account small dirt particles), and/or a floating layer, that covers more
than 75 % of the top sample surface, is detected.
Calculation of the filterability
...