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Marine Fuel Quality 2015 An Objective Review

Report for: INTERTANKO

Reference: TID 8108 Reporting date: February 2016 Report by: A.A. Wright

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Executive summary

Despite the maturity of the marine fuel market and a well-established marine fuel quality standard, ISO 8217, there remains a risk that the fuel supplied to a ship will be off-specification. From the FOBAS data for the first half of 2015 this risk over that period was of the order of 4 – 5 bunkerings out of every 100, the risk being slightly greater for the residual fuels as compared to the distillates.

For the residual fuels the principal reasons for being off-specification were excessive viscosity and water content however high abrasive content and asphaltene instability were also significant factors. In terms of the distillate fuels the principal reason for being off-specification over the same period was sulphur content exceeding the ordered 0.10% max limit as required in order to comply with the MARPOL Annex VI ECA-SOx requirements thereby placing users in potential breach of those requirements.

In assessing this 2015 data over a three year period going back to 2012 there is a noticeable consistency in these findings. The only marked difference being that, with the change of the ECA-SOx limit from 1.00% to 0.10% from 1 January 2015, the low sulphur compliance issue has now shifted away from the residual fuels to the distillates where it was already an on-going concern.

Additionally, the occasional incidence of deleterious chemical contamination continues to occur. A particular problem with this being that practically, from the receiver’s perspective, it can only be investigated once the problem has manifested itself.

Written by: Andy Wright Approved by: Timothy Wilson

Designation: Fuel Consultant Designation: Principal Specialist Fuels

Date of approval: Fuel Oil Bunker Analysis and Advisory Service (FOBAS) Lloyd’s Register GMT Ltd.

February 2016

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Contents

Executive Summary i

1. Introduction 1

2. Marine fuels in 2015 2

3. Factors potentially affecting the quality of the fuel as supplied to a ship 3

4. Relevance of FOBAS findings to world-wide fuel quality 5

5. FOBAS findings on fuel quality 1st January – 30th June 2015 7

6. Comparison of 2015 and 2012 - 2014 findings 11

7. Future issues 14

8. Concluding remarks 16

References 17

Appendix I - Summary of FOBAS Off-Specification Report findings 1st January - 30th June 2015 18

Appendix II - Off–specification residual fuel characteristics 2012 to 2015 19

Appendix III - Fuel quality aspects covered under Clause 5 of ISO 8217 21

Appendix IV – Consequences of off- specification fuels: case histories 24

Appendix V - A background to marine fuel quality 30


February 2016

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1. Introduction

Marine fuel quality has been an ongoing shipowners concern for decades – FOBAS, as Lloyd’s

Register’s fuel testing service - has, for example now been in operation for over 34 years in order

to meet the demand in this area for factual data and well-founded, knowledgeable, engineering

advice.

This review seeks to set this marine fuel quality issue into context and to factually demonstrate

that while the majority of fuels as supplied are of acceptable quality at that stage there is

nevertheless, despite the maturity of the market and the availability of knowledge and

information, a significant number of instances where there has been a failure to have the

necessary required quality control in place resulting in the delivery of off-specification fuels and

hence exposing the eventual user to the potential consequences of that failure.

However the assessment of what represents marine fuel quality is a multi-faceted issue and is

not summed up by any single parameter. Although the ongoing development of the

international marine fuel specification, ISO 8217 [1], has materially assisted in quantifying many

of the principal characteristics which define a fuel as delivered – recognising that adequate

onboard treatment is an essential subsequent stage - there still remain significant challenges.

The reality of current marine fuel supply systems and procedures is that the user only receives the

fuel that is actually delivered; not necessarily that as ordered by the user or that as intended by

the supplier. Therefore, as a starting point to the satisfactory use of a fuel it needs to be actually

delivered to the ship meeting the quantified limits of the applicable specification, for example

ISO 8217:2012 RMG380, since given the commercial and operational realities these dictate that,

apart from in the most extreme cases, a fuel once loaded onboard has to be used. However,

there are a number of additional factors, mainly related to the nature of the components used in

the production of that fuel, which are not readily quantified or capable of verification at the time

of delivery which can result in serious operating consequences. Therefore, fuel suppliers cannot

simply consider marine fuel as an amorphous, uniform, commodity but must have in place

robust and actually implemented quality control systems which ensure that the fuels they supply

are comprised of acceptable components, homogenous and within specification at the point of

delivery.

Within this review the term ’shipowner’ is used to represent that party responsible for the ship

although in practice it is recognised that through the actions of managers and agencies this is in

reality often a far more complex relationship.

Marine Fuel Quality 2015 An Objective Review February 2016

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2. Marine fuels in 2015 Setting the Scene

For the purposes of this review the term ‘marine fuel’, also known as bunkers, is taken to mean

those conventional liquid fuels as produced by the refining or processing of petroleum. Typically

these marine fuels are sub-divided as being either distillates or residuals. Distillate fuels being

categorised as those fuels that do not require heating to achieve injection viscosity whereas

residual fuels do require such heating.

Within this context distillate fuels, often also referred to as gas oils, are generally the direct

product of the refinery or allied processes, such as gas-to-liquids, from which they were

produced although they could be mixed with other similar materials during the various stages of

production and distribution. These fuels may be dyed and in some instances the incorporation of

trace quantities of residual product is permitted; typically the line washings during supply where

the distillate is delivered after the residual. These distillate fuels may include a proportion of a

bio-derived product; in some counties a certain inclusion being mandated.

Residual fuels are formed principally from the un-distilled and often cracked portion of the crude

oil being processed together with various off-runs and side streams from the refinery processes

which are thereafter blended with lighter materials as necessary to meet particular product

specifications. The lighter blend stocks so used being either distillates or cutter stocks; the latter

being the generally higher boiling point, but not residual fractions, from various refinery

processes such as thermal or catalytic cracking.

Over the last year or so this classic two-part split of the marine fuel market has been augmented

by the appearance of a number of marine fuels of unconventional formulations. These fuels are

sometimes referred to as being hybrid fuels, however they are more appropriately referred to as

ultra-low sulphur fuel oils (ULSFO) or ‘ECA-SOx Fuels’, since they are blended to meet the 0.10%

maximum sulphur limit applicable under MARPOL Annex VI from 1 January 2015 in respect of

fuels to be used in the Emission Control Areas (ECA-SOx) .This requirement has prompted

suppliers to find alternatives to the more costly sulphur limited distillates but which reduce the

thermal gradient when changing over from or to those residual fuels still used outside the ECA-

SOx areas. These fuels therefore have some of the characteristics of distillates while at the same

time require heating in order to attain the required injection viscosity. As such these fuels should

be seen as off-takes from the existing refinery systems but suitable only for use in fuel and

machinery systems where there is a general availability of the required heating and treatment

capabilities.

Gaseous fuels, such as natural gas, and other liquid fuels such as methanol are outside the scope

of this review.

Marine fuel quality explained

A more detailed explanation into the issue of marine fuel quality as supplied to ships, the various

influencing factors and the means by which it is assessed is given in Appendix V, which

highlights some of the main reasons why marine fuel quality as supplied to the ship, at the

bunker manifold, remains such a contentious issue.


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3. Factors potentially affecting the quality of the fuel as supplied to a ship

A fuel supplier needs to have in place a robust and applied quality control system which

adequately addresses all those factors which affect the quality of the fuel which is to be supplied

and the ability to meet the ordered specification by:

Controlling the quality of the individual blend stocks used to produce the fuel

Avoiding the ingress of extraneous, potentially deleterious, materials within the

supplier’s (or upstream) storage, handling and delivery systems

Ensuring the correct blending procedures are applied - either in the shore-side tank

farm or at the point of delivery

Blend stocks

The actual physical supplier may be the marketing arm of an organisation which also operates a

refinery or group of refineries in which case they may receive their blend stocks directly from

those sources. In other instances, the blend stocks used will have been traded, potentially a

number of times, by brokers between the source and actual supplier with potentially splitting

and mixing of different consignments along the way. Irrespective of the particular route it is for

the participants in each stage in that process to adequately document the incoming products,

any processing / mixing undertaken and the outgoing products down that chain; that

documentation to be correct and as complete as necessary.

The basic quality of these blend stocks will be a function of the crude oils from which they were

produced and the refinery processes to which those have been subjected. In the case of the

residual fuel base stock this will be typically collected on a pool arrangement whereby any

number of differing processes feed into it and therefore it will not tend to be of a consistent

quality.

The concern in this area is that blend stocks are not fully documented, by accident or design,

and hence oil parcels which are for one reason or another unsuitable or unacceptable as fuel

components may get incorporated into the fuel production stream. Therefore, where there are

any uncertainties as to the nature and quality of a blend component to be used it is for the

supplier to resolve those issues before using it in the production of a fuel to be supplied to a ship.

Extraneous materials

Clearly in a well-managed fuel supply system there would be no ingress of any undesirable

material into the fuel, or its constituent components. Such material could be truly extraneous to

the fuel product; water (fresh / brackish / saline – together with the risk that it includes bacteria),

dust, maintenance materials or corrosion debris. Alternatively it could be other fuel /

hydrocarbon products: line residues, washings through to materials remaining in shore tanks or

barges (including unpumpables).

That such materials are present in a fuel may be due to faulty systems or equipment or a lack of

care and attention (or deliberate) by operators – whether this is at the fuel supplier stage or in

the supply chain prior to that point is immaterial to the receiver of that fuel since their concern is

the quality of the product received, not the upstream procedures by which it was produced over

which they have, of course, no control. Included within this topic, although not a listed or testing

detected quality aspect, would be the practice of routinely, as opposed to its correct usage only

for line flushing on completion of supply, air blowing into the fuel causing it to froth (cappuccino


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effect) thereby temporarily increasing the volume which is recorded and from which the invoiced

quantity, in tonnes, is determined.

In a number of instances this extraneous material is found to be waste chemicals and other such

material for which marine fuels are at times seen by some as a convenient disposal route. A

more detailed insight into the issue of these, often highly deleterious, materials is covered in

Appendix III which addresses some of those fuel quality issues additional to the specification

requirements under the ISO 8217 Tables 1 and 2 with some relevant case studies given in

Appendix IV.

Blend process

Blending of the various components from which the fuel as supplied is produced may be

undertaken ashore or at the point of delivery, in either case the supplier’s intent would be to

make the best use of the available component products so as to not give away quality

characteristics. However since a residual fuel needs to be blended to achieve the required

viscosity and density together with attention to the limit of the sulphur content (all other residual

fuel characteristics will usually be what they turn out to be) there will inevitably need to be some

compromises – hence, for example, the delivery on occasions of a fuel of much lower viscosity

than the maximum ordered.

For the blending to be undertaken correctly in the first instance there needs to be accurate data

in respect of the blend components to be used – viscosity and density (together with sulphur if

that is a factor). Secondly the blend proportions as determined from that data need to be correct

calculated and then set – and thereafter uniformly maintained.

Adjustment of the blend ratios over the supply period results in the delivery of a non-

homogeneous product, an issue which will not be detected from the continuous drip samples

taken over the whole of the bunkering period, but with potentially serious consequences to the

user particularly where the fuel is loaded in series into a number of different tanks.

It is of course the duty of the fuel supplier in producing the residual fuel to be delivered, or

indeed any other party upstream of that point, to ensure that any component blend stocks

which are to be mixed, and any light or cutter stocks used, are actually mutually compatible and

will not result in asphaltene precipitation. Furthermore, it needs to be ensured that the various

components are sufficiently well mixed together such that the fuel will not tend settle back out

over time to those original components – a process known as stratification – again an issue

which would not normally be detected from the continuous drip sample.

Quality control failures

Overall therefore, each instance where a fuel parameter has not met the specification

requirement is a case where the necessary quality controls, for one reason or another, have not

been effective and the supplier has therefore failed in their duty to meet the user’s ordered

specification. The frequency with which these quality control failures occur is addressed in the

following sections.


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4. Relevance of FOBAS findings to world-wide fuel quality

In drawing general conclusions from any set of data it is essential to understand how that data

relates to the total picture. In terms of fuel quality this is particularly relevant since there are

potentially many factors which could affect the assessment.

FOBAS as a fuel testing service has been in operation since 1982 providing a range of services to

shipowners in respect of both the fuel as received and as used. Principal amongst the services

offered is the ‘Routine Bunker Analysis Service’ covering the testing of receiver / user drawn

samples of the fuel as delivered to the ship together with, on the basis of the test results

obtained, associated technical comment highlighting any concerns and providing

recommendations regarding the use of that particular fuel.

Since there is no mandatory requirement to have the fuel as received tested the data from these

sources may be questioned as to the degree to which the findings from such a service provide a

fair representation of the global marine fuel quality issue. In the first instance the data could be

seen as being somewhat self-selecting – in that clearly it represents the fuel supplied to users

which choose to participate in such services and who therefore undertake more than the bare

minimum. Furthermore, the inputs, the samples received do not represent a statistically balanced

cross section of the world’s fuel supply –in terms of the suppliers, the ports of supply nor even

the quantities of the various fuel grades.

As to the actual samples tested, these can be taken as being representative of the particular

consignment of fuel in question. FOBAS provides instructions and guidance as to the correct

sampling procedures and the issues that those undertaking that sampling need to look out for in

order to obtain a worthwhile sample. Also supplied are the necessary sampling connections and

containers in order to draw the required bunker manifold drip sample across the whole of the

supply period. On the issue of user drawn samples there is no incentive on the part of the

persons drawing that sample to do it otherwise than correctly and to not adulterate it or

otherwise tamper with its representativeness since the primary purpose of the test results

obtained is to guide the ship’s engineers as to the use of that fuel. Where the test results

potentially trigger a claim against the supplier there will often be further samples drawn from

storage tanks and the fuel system to support the initial finding and secondly the supplier will be

undertaking their own testing on their retained sample before admitting any liability. Indeed in

instances where, due to carelessness or neglect, submitted samples have not been drawn

correctly this represents a wasted testing fee to the user with implications to those responsible.

The validity of the individual test results themselves is underpinned by the FOBAS laboratories all

being duly accredited and audited, the use of standard test methods and, perhaps most

importantly, their familiarity with performing the particular tests being undertaken.

FOBAS is a world-wide operation and therefore there is no particular geographic skewing of the

ports represented by the samples received. While there is a tendency for users to preferentially

send in samples of residual fuel, given the known operational issues, as opposed to distillates this

is common to all users and therefore by approaching the data generally on a relative, rather than

absolute basis, the quality findings are not affected. However, given that the users of testing

services are charged on a per sample basis there can be a tendency that ships loading only small

consignments of fuel, such as those in the coastal trades, to be underrepresented. Additionally

those users operating shuttle or scheduled services between set ports, where there is a particular

relationship with the supplier, may also not tend to use fuel testing services.

On the basis that tens of thousands of fuel samples are tested annually by FOBAS any local issues

would not affect the overall fuel quality findings. Furthermore, from discussions with other fuel


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testing services and observations of their reported findings there are no substantive differences

with their experiences.

The International Maritime Organization (IMO), in setting up the fuel sulphur monitoring

programme as required under regulation 14.2 of MARPOL Annex VI, considered that the data

from the fuel testing services represented the most reliable and comprehensive data sources

available. FOBAS has been a major contributor of data to that programme from the outset. The

consistency of the FOBAS data with that of the other data providers is illustrated by the fact that

for the 2014 assessment, for example, the FOBAS residual fuel sulphur weighted average of 2.45%

was only 0.01% below that determined from the all the input data.

The final point in this question as to the relevance of the FOBAS data to the global marine fuel

quality issue is what fraction of the total marine fuel supply is represented by the findings of the

fuel testing services? For the years 2011 [2] and 2014 [3] the IMO fuel sulphur monitoring

programme covered:

2011 2014

Residuals

Number of samples 97137 153719

Tonnage 87730775 116680203

Distillates


Tonnage 2768350 4144945

Totals


Tonnage 90499125 120825148

The above values can be shown with precision given since they are the direct sums of individual

substantiated data sets. In contrast, the IMO 3rd Greenhouse Gas Study 2014 [4] could only

estimate for 2011, for example as the latest year given, the total marine fuel consumption

(international + domestic + fishing) as 253 – 327 million tonnes. Hence on that basis for 2011

somewhere between 28-36% of the global fuel tonnage was included in the IMO’s fuel sulphur

monitoring programme at that date and, with the addition of an additional service provider in

2014, that proportion will have subsequently increased. Furthermore, in terms of the total

amount of fuels tested world-wide the above will tend to be an underestimation since samples

where there is no tonnage value given by the submitter have to be excluded from the testing

service data provided to IMO.

Therefore, in summary, on the basis of the reliability of the individual samples tested, the tests

used, the world-wide nature of the service, the number of samples tested, the consistency with

the findings of other fuel testing services and the fact that a significant proportion of the world-

wide tonnage of fuel supplied is tested there is strong case that the FOBAS finding presented in

the following section are a relevant guide to global fuel quality over the period considered.


February 2016

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5. FOBAS findings on fuel quality 1st January – 30th June 2015 As part of the wider FOBAS services, two Off-Specification Reports are produced every month in

respect of all valid ‘as supplied’ fuel test reports issued. The first covers reports issued 1st-14

th of

the month and the second 15th- end of month. Only samples which are advised by the client to

have been drawn from the fuel receiving manifold using a continuous drip sampling process, or

equivalent, are included. Test results are given against the port of supply and the specification

limit or requirement against which they have been assessed.

Approach taken

For the purpose of these Reports the assessment of off-specification is against the current edition

of the ISO 8217 specification although it is recognised that at least some of the samples received

will be in respect of fuels which have been ordered and supplied against earlier editions. Off-

specification findings in this context are in accordance with the procedure given in ISO 4259[5];

that is from the receiver’s perspective test results which exceeded the relevant maximum limit

given in the specification by more than the 95% confidence margin. For these Reports the same

applies, in reverse, in respect of minimum limits except in the case of Flash Point for which all

findings below 60oC are given. A full discussion of the application of ISO 4259 to ISO 8217 is

given in the CIMAC publication ‘Guidelines on the Interpretation of Marine Fuel Oil Analysis Test

Results’ [6].

A summary of these reports, covering the period 1st January – 30

th June 2015 is given in

Appendix I. This period therefore represents the first six months of the MARPOL Annex VI

regulation 14 Emission Control Area fuel sulphur limit being 0.10% maximum, as opposed to

the 1.00% maximum which had applied since 1st July 2010, and hence the general use of

distillate type fuel to meet that requirement rather than the controlled sulphur content residual

fuel which had been widely used previously.

Findings

The findings from these Reports are given as percentages. As discussed in the previous section it

is considered that these FOBAS findings are representative of fuels as supplied world-wide and

are free of any particular skewing either in terms of regions or fuel grades. While the numbers

given in the tables below are considered to be generally applicable to all as supplied fuels world-

wide there will inevitably be certain detailed differences with findings from other datasets,

however it still serves to illustrate the same message.

Over the whole the period 1st January – 30

th June 2015 the overall occurrence of Off-

Specification Report findings was 4.5% of all the samples tested; ranging from 2.6% to 5.6%

for the individual Reports. This range in the proportions of off-specification findings between

individual Reports high-lights the need to assess fuel quality issues from large data sets spread

over extended periods.

Split between the fuel types, the average occurrence rate for the residual fuels tested over that

period was 4.7% as against 4.2% for the distillates


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It should be noted that where there is a quality issue with a particular fuel as supplied it may be

such as to affect more than one characteristic; for example a shortfall in the quantity of light

blend stock used to produce a particular residual fuel could result in both the viscosity and the

density values exceeding the relevant specification limits. Consequently, this overall off-

specification occurrence rate of 4.5% will in fact represent, in terms of whole numbers, less than

the 9 actual bunkering operations out of every 200 as given by that percentage.

To put this into a more specific context, ships generally bunker some 7-10 times a year – on that

basis a particular ship could, on average, currently expect to receive an Off-Specification Report

finding once every 2-3 years.

The following tables give the occurrence of an off-specification characteristic as percentages for

the period 1st January – 30

th June 2015 for both distillate and residual fuels against the total

numbers of the samples received for the respective fuel types. Additionally, in order to present

these in terms whole numbers, these percentage values are also expressed in terms of the

occurrence of the particular characteristic being off-specification per 10,000 bunkering’s over

that period:

Table 1 - Distillate fuel off-specification by characteristic (Jan-Jun 2015)

Characteristic Off-specification occurrence

of fuel as supplied

% Per 10,000

bunkerings

Sulphur (0.10% max) 1.56 156

Pour Point 1.26 126

Carbon Residue (on 10% residue) -

DM other than DMB

0.37 37

Viscosity at 40oC – max limit 0.26 26

Carbon Residue - DMB 0.24 24

Lubricity 0.22 22

Flash Point 0.20 20

Water 0.07 7

Viscosity at 40oC - min limit 0.02 2

Cetane Index 0.02 2

Ash 0.02 2

From the above it is markedly evident that for the distillate fuels the greatest occurrence of off-

specification was encountered in respect of sulphur and pour point. Thereafter it could be

viewed that there is a second ranking of occurrences covering carbon residue through to flash

point with the remainder occurring as isolated instances.

Sulphur

Previously with the ECA-SOx fuel sulphur limit set at 1.50% and then 1.00% that was a major

reason for residual fuels to be off-specification and this appears to be a continuing trend now

with the distillates being the fuel type used in those areas. In this it is to be noted that generally

there is only a narrow margin between the supplied value and the limit value with consequently

only a limited tolerance to less than fully robust supplier quality controls on that parameter.


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Flash Point

As noted above the 95% confidence margin, which for distillate fuels would exclude those of

57.5˚C and above, is not applied to the flash point data included in the Reports. If it had been

there would have been only a single entry – one instance of 53 ˚C which, to put into a wider

context, is still above the US automotive minimum limit.

Table 2 - Residual fuel off-specification by characteristic (Jan-Jun 2015)


of fuel as supplied

% Per 10,000

bunkerings

Viscosity at 50oC 1.70 170

Water 1.01 101

Density at 15oC 0.48 48

Ash 0.39 39

Aluminium + Silicon 0.35 35

Total Sediment: Aged 0.24 24

CCAI 0.16 16

Carbon Residue 0.09 9

Used Lubricating Oils 0.09 9

Sodium 0.09 9

Vanadium 0.05 5

Sulphur (3.50% max) 0.05 5

Pour Point 0.02 2

Flash Point 0.01 1

From the above it is markedly evident that for the residual fuels the greatest occurrence of off-

specification was encountered in respect of viscosity and water. Thereafter there is a second

ranking of occurrences covering ash through to CCAI with the remainder occurring as isolated

instances.

Viscosity

In the case of the off-specification residual fuel viscosity the principal concern is whether it will

still be possible to attain the temperature for the required injection viscosity, usually 12-15 cSt,

itself typically a range of around 10˚C. Off-specification was more common for the IFO 180 as

opposed to the IFO 380 grades. For these instances of off-specification viscosity:

48% required an increase of injection temperature of less than 3˚C

38% required an increase of injection temperature of 3 - 6˚C

14% required an increase of injection temperature of greater than 6˚C

Water

Water as a contaminant to the fuel is typically not uniformly distributed across the whole of the

supply and therefore tends to be encountered as slugs which can therefore affect the drawn

sample. Consequently, in instances of a very high water content in the sample (i.e. above 2 %)

may not be exactly matched in subsequently drawn tank samples. Nevertheless, the overall


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finding is generally that there was at least elevated water content. Of these water off-

specification (0.50% being the given limit value) cases:

66% were ≤ 1.00%

25% were > 1.00%, ≤ 2.00%

9% were > 2.00%

Total Sediment: Aged

The total sediment test is included in the specification as an indicator of unstable fuels; residual

fuels which will precipitate asphaltenic sludge with serious, even catastrophic effects on the

engine and fuel treatment system performance. However, it is a test with a relatively wide 95%

confidence margin (0.05% as compared to the limit value of 0.10%) and can be affected by

factors other than precipitated asphaltenic material. While some 40% of these off-specification

FOBAS findings (> 0.15%) were principally due to toluene insoluble material in the fuel (ie non-

asphaltenic material) that still left around a third of those instances, 8 in 10,000, which indicated

a clear risk that the fuel as supplied was unstable.

Aluminium + Silicon

The sum of these elements is taken as representing the potentially highly abrasive catalytic fine

content but can also be due to other materials, if mainly silicon it probably represents earthy /

sand type material which is more readily reduced by onboard treatment. Of these aluminium +

silicon off-specification cases (i.e. >72 mg/kg):

39% were ≤ 80 mg/kg

34% were > 80 mg/kg, ≤ 100 mg/kg

26% were > 100 mg/kg

Overall comment

Hence despite the decades that the ISO 8217 specification has been in existence and in use there

still remain a significant number of instances where the fuel as delivered was outside the

required specification.

A number of such case studies are given in Appendix IV covering instances where either the

listed characteristics in ISO 8217 were off-specification or where the fuels in one manner or

another did not comply with the Clause 5 requirement of that standard.


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6. Comparison of 2015 and 2012 - 2014 findings

In order to assess the general representativeness of the fuel quality data of the 6 month period reviewed,

1st January – 30

th June 2015, in Section 5 that data has also been compared to the FOBAS data for the

previous 30 month period 1st July 2012 – 31

st December 2014 in order to cover in total a three year

period. This comparison is summarised in Table 3 in respect of the total numbers of findings in the

individual Off-Specification Reports issued over those respective periods.

Table 3 Comparison of 2012-14 and 2015 periods

% off-specification 2012-14 2015

Distillate fuels 4.3 4.2

Residual fuels 6.6 4.7

In terms of the individual off-specification occurrence rates for the distillate and residual fuels these are

shown respectively in Tables 4 and 5 on the same basis as in the previous section of this review.

Table 4 - Distillate fuel off-specification by characteristic (2012-2014)

Characteristic Off-specification occurrence of

fuel as supplied

% Per 10,000

bunkerings

Sulphur (0.10% max) 1.69 169

Pour Point 0.58 58

Carbon Residue (on 10% residue) -

DM other than DMB

0.43 43

Viscosity at 40˚C – max limit 0.73 73

Lubricity 0.24 24

Flash Point 0.31 31

Water 0.13 13

Cetane Index 0.01 1

Table 5 - Residual fuel off-specification by characteristic (2012-2014)


of fuel as supplied

% Per 10,000

bunkerings

Viscosity at 50˚C 2.26 226

Water 1.03 103

Sulphur (1.00% max) 0.70 70

Density at 15˚C 0.56 56

Aluminium + Silicon 0.82 82

Total Sediment: Aged 0.29 29

CCAI 0.36 36

Carbon Residue 0.10 10

Sulphur (3.50% max) 0.06 6

Pour Point 0.02 2

Flash Point 0.01 1


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Comparisons in the percentage occurrence of off-specification findings in respect of a number of the

individual fuel characteristics are given in Figure 1 and Figure 2 for the distillate fuels and residual fuels

respectively.

Figure 1 Distillate fuels - comparison of 2012-14 and 2015 off-specification findings

Figure 2 Residual fuels - comparison of 2012-14 and 2015 off-specification findings


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The noticeable feature of the summary in Table 3 is that while the distillate fuel off-specification occurrence rate is relatively consistent in contrast for the residual fuels in contrast there is a marked decrease in the rate for 2015 as compared to 2012-14. As noted in the above discussion, the period under review followed directly on from the change in the ECA-SOx fuel sulphur limit from 1.00% - which had in some part been met by use of sulphur content controlled residual fuel – to 0.10% which was generally a distillate fuel. Hence, as shown in Figure 2, off-specification in terms of the 1.00% sulphur limit, which was one of the principal reasons for being off-specification in the 2012-14 data, no longer features for the 2015 period. That the occurrence of off-specification sulphur in respect of the distillate fuels is relatively consistent, Figure 1, between the two periods may be attributable to the fact that since 2010 the principal reason for off-specification was already failures to meet the 0.10% sulphur limit as introduced by the EU Sulphur Directive in respect of the fuel used by ships while ‘at berth’ – that this limit now also applies to the ECA-SOx areas has not therefore dramatically changed the likelihood of off-specification. In terms of the distillate fuels as shown by Figure 1 the marked change between the 2012-14 and 2015 periods is in that while the occurrence of off-specification high viscosity has decreased paradoxically the occurrence of off-specification pour point has increased – possibly indicating an increased tendency to use high wax component blend components in order to achieve the required sulphur limit. The occurrence rates for the other distillate fuel characteristics being generally consistent between the two periods. In terms of the residual fuels as shown by Figure 2 further implications of the disappearance of the 1.00% max sulphur residual fuel grade are seen in the markedly reduced occurrences of off-specification aluminium + silicon and CCAI reflecting the previous use of the low sulphur side-products of refinery catalytic cracking – relatively high density / low viscosity products rich in abrasive aluminium and silicon ‘cat fines’ – as blend components in order to meet that 1.00% sulphur limit. Nevertheless despite that reduction in occurrence of aluminium + silicon off-specification it still remains a significant factor. Although the occurrence rate of off-specification viscosity decreased in the 2015 period as compared to that for the 2012-14 period it still remains, by an appreciable margin, the principal issue. In respect of the other characteristics such as water, density and total sediment these are essentially consistent between the two periods. Month-by-month occurrences of off-specification findings for the principal residual fuel quality characteristics - viscosity, water, aluminium + silicon and total sediment: aged - over the three year period covered by this review are given in Appendix II.


14

7. Future issues In terms of the future fuel quality it is not intent of this review to attempt to predict how the

distribution and frequency of the off-specification occurrences as given in section 5 will develop

– either as a result of the general commercial and technical dynamics or as a result of any

statutory action which may stem from the discussion currently underway within IMO on fuel

quality. There are however two aspects from the existing MARPOL Annex VI which are expected

to present significant impacts on future fuel quality issues.

Outside ECA-SOx sulphur limit

As given in the existing regulation 14 of MARPOL Annex VI the outside ECA-SOx limit is set to be

reduced from the current 3.50% limit to 0.50%. IMO has now commenced the process which

will decide whether that is to occur 1st January 2020 as given or is to be deferred to 1

st January

2025 on the basis of the expected availability of fuels meeting that requirement. However,

irrespective of the outcome within IMO the European Union has already established, through the

Sulphur Directive, that the maximum fuel sulphur limit for those EU waters (which include the

exclusive economic zones and pollution control zones of all Member States) which are not ECA-

SOx will be 0.50% from 1st January 2020.

Whereas the previous ECA-SOx fuels with sulphur limits of 1.50% and then 1.00% were

generally sulphur controlled residual fuels and the current, 0.10%, limit is generally a distillate

product it is to be anticipated that there will be no such clear assumption as to the fuel type to

be used to meet this 0.50% limit.

It is the FOBAS expectation that the whole range of fuel types may be used to cover this

requirement; distillates, blended diesel oils, light fuel oils through to the residual grades. Hence

from different suppliers and different ports around the world there will be widely differing fuel

types being provided.

Therefore in the future this 0.50% sulphur limit will be the major driver to formulating the fuel

composition and hence the quality since all other characteristics will be secondary to that core

sulphur requirement.

Tier III NOx controls

To date the NOx controls given by regulation 13 of MARPOL Annex VI have had no impact on

the ship’s fuel quality requirements since the Tier II, and preceding Tier I, limits have been met by

means of ‘in engine – no consumables’ controls.

The Tier III NOx controls are applicable to engines installed on ships constructed on or after 1st

January 2016, and to additional / non-identical engines installed on other ships on or after that

date, but only while operating within the designated ECA-NOx areas – currently the North

American and US Caribbean Sea areas. To meet these Tier III levels the general expectation is

that most engines will be fitted with selective catalytic reduction (SCR) units which will have

certain fuel quality implications.

SCR units are not necessarily very tolerant of fuel sulphur – combined with the urea reductant

used in such systems it can result in the formation of ammonium sulphate which then precludes

the required reduction of NOx to nitrogen and water vapour but which can also quickly

accumulate to the point that the SCR becomes so choked as to block the flow of exhaust gas. At


February 2016

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present, the two areas which are ECA-NOx are also ECA-SOx so in those areas the fuel sulphur

content will be limited to 0.10% maximum. Therefore fuel sulphur control in these instances will

not only be an issue in terms of statutory compliance but also a factor which will have direct

operating, even safety, implications.

A further, and potentially more fundamental, issue with SCR units will be the presence of certain

ash elements in the exhaust gas stream – primarily from the fuel as used but also from the

engine’s burnt or entrained lubricant. This will be an ever present issue, unlike the sulphur case

which is only an issue when the SCR is operating (urea being injected), since although the SCR

will only be required to be operated within the ECA-NOx areas exhaust gas will continue to flow

through these units at all times (designs seen to date do not tend to incorporate exhaust gas

bypass ducts). Alkaline (i.e. sodium and potassium) and earth (i.e. calcium and magnesium)

metals together with arsenic can have substantial blinding and deactivation reactions with the

catalytic blocks used in the SCR.

Consequently there may need to be a far tighter control on fuel ash elements in the fuel as

supplied – since generally these are not elements (apart from, to a degree, sodium) which are

amenable to onboard treatment - than is currently the case with again major implications on the

operability of what will be expensive and essential (if to meet NOx control requirements) items of

ship’s equipment.


16

8. Concluding remarks As identified in this review there is no simple go / no go answer to the issue of fuel quality –

either as supplied or as used. The fuel received is only that which comes onboard and if at that

stage it is not within specification then the user is already presented with a number of problems

– some which can be perhaps managed, at a risk and with additional effort, and some which

cannot.

As shown from the actual FOBAS fuel test results for the first six months of 2015 there are fuels

which should not have been supplied – above limit sulphur levels, unstable fuels and fuels with

excessive levels of catalytic fines – however while these are far from being the majority each

instance is an instance which should not have occurred and an instance where the ship was, at

least to some extent put at risk- either in terms of statutory compliance or operational capability.

While an initial assessment of quality of the fuel as supplied can be undertaken against the

qualified limits of a specification, such as those given in Table 1 or Table 2 of ISO 8217, it is only

the starting point.

In addition there are other factors – mainly linked to the nature of the blend components used –

which are not readily assessed in terms of the fuel as delivered. In respect of these the shipowner

is totally dependent on the supplier having excluded them from the outset since there are no

means onboard by which a fuel that is, for example, corrosive or heavily laden with semi-solid

chemical materials can be rendered safe to use.

Therefore from this review it would be summarised:

There remains a significant risk of a ship receiving off-specification fuel

This off-specification risk is slightly greater in respect of residual fuels as opposed to

distillates

With residual fuels there remains a clear risk that off-specification will be in respect of

either asphaltene stability or abrasive content with serious implications for the usability

of that fuel

For distillate fuels the major risk is that the sulphur content will not meet statutory

requirements

On occasions, incidents of unusual deleterious extraneous material in fuels as supplied

are encountered.


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References

1. ISO 8217:2012 Petroleum products – Fuels (class F) – Specifications of marine fuels

2. IMO, MEPC 64/4: Sulphur monitoring for 2011

3. IMO, MEPC 68/3/2: Sulphur monitoring for 2014

4. IMO, MEPC 67/INF.3: Third IMO Greenhouse Gas Study 2014

5. ISO 4259:2006 Petroleum products – Determination and application of precision data in relation to methods of test

6. CIMAC Guideline 2015: The Interpretation of Marine Fuel Analysis Test Results


18

Appendix I - Summary of FOBAS Off-Specification Report findings 1st January - 30th June 2015

The following tables give the incidence of off-specification findings by the Reports in which they

were included. Period 1 is for reports issued 1st – 14

th of the month, Period 2 for reports issued

15th to the end of the month.

In this context off-specification means outside the 95% confidence margin as given by ISO 4259

from either the ISO 8217:2012 limit or, in the case of sulphur, the required limit. The exception

to this approach is flash point for which all findings of values below 60˚C are included.


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Appendix II - Off–specification residual fuel characteristics 2012 to 2015

In order to give further detail in respect of the encountered variations in occurrences (expressed

as % of the total number of residual fuel samples received that month) over time these are set

out below for the principal off-specification characteristics over the three year period covered by

Section 6 of this review:


20


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Appendix III - Fuel quality aspects covered under Clause 5 of ISO 8217

Background

Experience has repeatedly shown that engine operating problems can still occur despite fuels

having met the relevant ISO 8217 Table 1or Table 2 limits. ISO 8217 requires that “the fuel

should be a homogeneous blend of hydrocarbons derived from petroleum refining”. This

situation has often led to speculation that fuel related operational problems and marine engine

failures have been caused by the presence of specific chemical species which are viewed as

extraneous ‘contaminants’. Whilst it is accepted that some of these chemical species are clearly

not derived from petroleum refining, it is a subject of some debate and, even disagreement,

whether certain of the other alleged “contaminants” are truly extraneous contaminants, since

they may actually arise directly from the refining process, in other words are naturally occurring

chemical species.

The presence of so-called “contaminants”, in marine residual fuels, and indeed in some cases

also in the distillate fuels, is therefore an issue of continued concern for shipowners and other in

the marine industry. Though a consensus exists that there is a need for a better understanding

of the relationships between their presence in a fuel and its operational characteristics, it is still

not clear what constitutes a ‘contaminant’ and critically what constitutes a detrimental

concentration, what is clear however is that the supply chain from refinery through storage to

delivery to the ships bunker manifold is open to potential cross contamination and poor blending

practices.

The ISO 8217 refers to such materials as ‘deleterious materials’ which are impractical to test for

on each bunker delivery and for which mostly do not have any uniformly adopted standardised

analytical methodology for checking their presence in a marine fuel. This is addressed in more

detail in Annex B of the standard.

It is therefore incumbent on the supplier to ensure that the supply chain, from refinery through

to delivery, has in place adequate quality assurance management practices such that the fuel

delivered is not only in conformity with the defined characteristic limits as given in Table 1 or

Table 2, as applicable, of ISO 8217 but also the requirements of Clause 5 of that standard.

Examples of extraneous deleterious materials that have been detected by FOBAS:

Polymers: Such as polypropylene, polyethylene or polystyrene. A well understood

contaminant, which resulted initially in unexplained filter blockages restricting, even

completely choking, fuel flow to the combustion machinery. This issue became quite

prolific and lead to a series of cases being reported back in the late 1990’s. Although

less of an occurrence today it is often one of the first suspects when unexplained fuel

filter blockages are being experienced. Almost impossible to detect at delivery since the

usual routine bunker fuel sample with a typical size of 500-750 ml is insufficient to be

certain to pick up trace polymer fibres or globules, so where this is suspected verification

analysis usually requires additional, specific, samples from the fuel system and sludge

caught in the hot filters where blockages are occurring.


22

Chemical species / compounds: such as:

Polyvinyl acetate Tall oil

Hexanol,alpha – pinene Butoxy butanol

Glycerides Diethylhexyl phthalate (plasticising agent)

Butanol Alpha-pinene

Butyl acrylate Heptanol, dioxane

Phenoxy ethanol Phenol

Phenyl ethanol Trimethylene norbanane

Methyl benzyl ether Phenoxy propanol

Glycols Bisphenols

Glycerol Tri butyl tin

The above list, of course, cannot be exhaustive. Experience indicates that the most likely

outcomes of the presence of such extraneous deleterious materials in the fuel as

supplied are corrosion, deposit formation and formation of films (lacquering), with the

latter two being more frequent than corrosion. At what levels any one, or combinations

of, these chemicals will result in difficulties is problematic (see Appendix IV for case

histories) hence all fuels as supplied should be free of any such materials.

Where extraneous chemicals are present the outcome can, as a minimum, result in

having to deal with additional sludge from separators and filters but in extreme cases

results in excessive sludging and filter blocking, and hence engine fuel starvation,

together with machinery damage – particularly fuel injection system components.

Acids: such as:

Palmitic Oleic

Stearic Rosin

Dodecanoic Tetradecanoic

Hexadecanoic Octadecanoic

Hydrofluoric Sulphuric

As with the chemical species and compounds above, the effects of the presence of such

acids in the fuel as supplied is not readily predictable although in this instance the

primary risk is corrosive attack of fuel treatment system and engine components.

Onboard treatment would again be expected to be ineffective in preventing problems

but at what concentrations of any one (or in combinations with other acids or

extraneous chemicals) of these will cause problems is undefinable and hence any fuel

should be completely free of such extraneous contaminants. Where problems have been

encountered with such fuels the experience has been that components such as fuel

injector pumps have been degraded to the point of failure in a short space of time yet

seemingly other ships which received parallel supplies of that fuel reported no problems.

Bacterial contamination

Where water is present in a fuel as supplied it may be contaminated with bacteria and

which then may be carried over from poorly maintained storage tanks on shore to ship.

These microbes can further multiply in areas where settled water accumulates. This can

lead to at the least filter blockages and fuel flow restriction leading to worst case

scenarios of corrosion on the fuel system components.


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Atypical asphaltenes

The nature of residual fuel oil coming into the marine supply chain is influenced by the

diversity of the crude oil sources, the refinery processes and the various streams of cutter

stocks used to meet the particular ordering specification. Atypical asphaltenes, have

been suggested as being one cause of heavy sludge deposition at the purifiers, not

related to fuel stability condition, and are suspected as being a consequence of some of

the more severe fuel production processes.

Quantification of extraneous deleterious materials

The above listing should not be considered as being complete. Furthermore the

characteristics listed do not necessarily result in observed operating problems which may

be due to factors such as the concentrations present, combinations with other materials,

applied temperatures or the particular fuel system equipment / engine type / model in

which the fuel in question is used.

Frequency of occurrence

FOBAS’s experience is that about 0.2% of bunkers result in a need for extended

investigative analysis to address reported concerns and or operational problems being

encountered on board. Of these some 0.01% are as a result of the presence of

unexplained presence of chemical species and contamination from other foreign matter

as described above. The issues experienced could range from simply being an

inconvenience of a higher frequency of filter blocking occuring to fuel pump seizure or

rapid wear and costly engine damage. Whilst this figure of 0.2% may seem insignicant it

does equate to 20 bunkerings out of 10,000 loaded, which is no lesser matter to the

particular ship concerned.

Ignition and Combustion. Performance

In this it is to be noted that combustion performance is distinct from ignition performance, the

latter being assessed in terms of indicators such as Cetane Number or Cetane Index and to a

lesser extent by the CCAI value.

Although a fundamental requirement of any fuel is that it must deliver acceptable combustion

performance there is currently no test process by which this can be readily quantified in a manner

suitable for inclusion in a fuel quality specification such as ISO 8217. Indeed different engines will

have differing combustion performance from the same fuel – in part from their design

parameters by also affected by the service load and their overall maintenance condition. Further

details are given in the CIMAC Fuel Quality Guide – Ignition and Combustion.


24

Appendix IV – Consequences of off- specification fuels: case histories

Case 1: Chemical contamination

The following case is selected to illustrate the point that there is more to assessing fuel quality

than simply a comparison to the requirements of Table 1 or Table 2, as relevant, in terms of the

fuel as supplied.

A sample of the residual fuel, as delivered to a ship, was tested in the usual manner and found to

comply with the requirements of Table 2 (RM grade) of ISO 8217:2012.

However, when brought into service fuel filtration problems were immediately experienced which

were so severe as to heavily restrict the flow to the engine thereby compromising deliverable

power capability and response. The de-sludge frequency of the automatic backwash filter

increased sharply and this necessitated additional manual cleaning. In order to investigate the

reasons for these problems samples were drawn across the fuel system from storage through to

engine fuel rail together with a sample of the filter deposit material.

On analysis the fuel was found to contain various

fatty acids, bisphenol tars, 1-tetradecane and an

ethylene based polymer/copolymer.

Such materials derive neither from the crude stock

used nor the usual refinery processes and had been

identified as being present in previous cases of fuel

filtration blockages and fuel injector / pump seizures.

Consequently, there was good reason to conclude

that the chemicals identified had been the cause of

the operational problems encountered.

The supplier initially refuted this finding but, on undertaking their own internal investigation,

found that the fuel as supplied had indeed been contaminated with the identified chemicals.

Since the use of the fuel in question coincided with the operational problems it was deemed to

have failed to have met the Clause 5 requirements of ISO 8217. Since the fuel was demonstrably

unusable the supplier agreed to de-bunkering.

Blocked Filter Cage

GCMS chemical analysis


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Case 2 – Unstable fuel

Despite the fuel being found to be off-specification shortly after being delivered this case

illustrates the time, effort, inconvenience and cost that can occur - in this instance the associated

costs were around $500k and it took some 4 years to resolve.

The ship loaded the fuel in Rotterdam (over 600t) which was routinely analysed and the Total

Sediment Potential analysis (carried out to determine the thermal stability of the fuel) was found

to be 0.26% m/m instead of a maximum of 0.10% m/m as given by ISO 8217. This was reported

to the charterers who informed the suppliers and who in turn rejected the claim.

A further sample was taken and a similar result

reported. Meanwhile the owners were requested

by the supplier to try and use the fuel which they

did, but had serious problems with filters blocking

and purifiers becoming clogged up and having to

be cleaned many times a day together with

engine operating problems.

The ship was en route to Singapore and was by

then in the Mediterranean. By that time the

supplier had acknowledge that the fuel indeed

had ‘high sediment’ issue but that ‘… it should

not be a problem for the main engine ...’.

However, due to the problems already encountered,

others fuels, including distillate which was already

onboard, were instead used. In Singapore, three

months after the fuel was supplied it was eventually

de-bunkered.

This all took place in 2011 yet the claim was finally settled

against the supplier towards the end of 2015, the cost of

the claim was over $500k.

Asphaltene sediment from tank bottom

Asphaltene sediment blocking fuel lines

Separator overloaded with asphaltene

sediment


26

Case 3 – Fuel pumps and filtration problems A ship loaded fuel in Houston in February 2015. After starting consumption from this batch, it experienced issues related to filtration problems and sticking fuel pumps. At one point the problems reached such severity that even propulsion power was lost. On testing the fuel in question an additional acid number test was also undertaken in order to determine the level of acidic components in the fuel which gave a result of 0.63 mg KOH/g. Based on the feedback, it was decided to run further in-depth testing to determine the nature of acids present in the fuel and determine the possibility of external contamination. GCMS data from the derivatised SPE polar extract suggested low level presence of a variety of oxygenated species, including glycols, glycol ethers, fatty acids, bisphenols and biphenyl diols. Several nitrogen-containing oxygenates were also detected. In other

words the fuel was contaminated by a composite of chemical wastes. Sources of some of these components were unknown, but they were not products of regular petroleum refining. Whilst little was known of the impact of the reported chemicals on the machinery plant, other FOBAS experiences from dealing with fuels with the presence of bisphenols and complex fatty acids showed that in some cases such fuels have the tendency to cause various operational problems which may range from unusual sludge deposit formation at the filters and purifiers through to the excessive wear of fuel injection and cylinder components.

Case 4 - Catfines – abrasive damage and its costs

Catfines, the aluminium and silicon oxides debris which were formerly the carriers of refinery catalysts, is one of the more common residual fuel concerns. Although generally present to at least some degree in most fuels but if supplied over the specification limit represents a serious risk of damage to fuel system and cylinder components in a short space of time. An example of this issue is in respect of a ship that bunkered in Panama from a trusted supplier. The ‘as delivered’ fuel sample was received shortly thereafter and on testing was found to have a very high, 135 mg/kg, level of catfines (as indicated by the aluminium plus silicon findings). The shipowner was contacted immediately and advised of the possible consequences of using this fuel but at first could not believe that a fuel of this quality could possibly have been delivered from this reputable supplier with whom they had been dealing with for many years without any problems. However, almost simultaneously, the ship had started to report serious operational difficulties whilst using the fuel.

Fuel pump plunger damage


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Cylinder liner wall embedded with

abrasive catalytic fines – which

causes rapid wear of liners and

piston rings

As the ship had only just left port and given that they did not have any other residual fuel onboard, it was requested to switch to gasoil and return to port. The supplier was immediately put on notice for supply of

an off-specification fuel and for any damages caused to the ship’s machinery resulting from the use of the fuel. In port the main engine was examined and high wear to the cylinder liners and piston rings was observed.

Damage to several of the cylinder liners was so bad that they had to be replaced despite the fact that this high catfine fuel had been in use for only a short period of time. The cost of such off-specification fuels can vary considerably depending on the extent of the resulting damage, noting that many instances both the main and auxiliary engines may use the same fuel. Hence the total cost of the damage to fuel injection system components, piston rings and liners can vary anywhere from $100,000 to over S1,00,000 when adding in off hire, voyage diversion and other costs.

In a particular instance of high catfines being present in the fuel as supplied the direct itemised costs were as shown in the following Table A4-1 (i.e. not including loss such aspects of loss of hire and opex during off-hire):

Table A4-1 Cost breakdown as a result of off specification, high catfine, fuel being supplied


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Case 5 – Excessive sludge generation at the separator The vessel reported excessive sludge generation at separation plant during the use of fuel loaded from Zeebrugge in December 2015. The initial analysis of the bunker manifold drip sample showed the fuel to have above average sediments levels but which were however still within the 0.10% m/m limit of ISO

8217 standard. The other test results were all within the Table 2 requirements. The ship however experienced on-going operational problems with the fuel in use, so further testing was undertaken in order to determine the root cause of the problems being reported. Both FTIR and GCMS analyses were performed on the fuel to determine whether there was presence of any external contamination. Additionally an acid number test was performed which showed the results 0.68 mg KOH/g. GCMS/FTIR analysis indicated high levels of Estonian shale oil present in the fuel. Semi quantitative analysis tentatively placed the concentration of shale oil at 28% by weight. It should be noted that ISO 8217 recognises oil derived from tar sands and shale as ‘petroleum’ and therefore its presence in itself

is not considered as anomalous with requirements of ISO 8217. However, FOBAS experience shows that in few cases that the inclusion of certain young types of shale oils (especially Estonian shale oil) in the fuel has the potential to affect the stability of the fuel blend and thus have the tendency to cause sludging problems especially at the separation plant. In view of the in-depth analysis performed it was concluded that the operational problems reported by the ship were caused by the poor stability of the fuel resulting from the presence of Estonian shale oil detected through FTIR/GCMS testing. In this instance therefore the fuel would be considered not to have met the Clause 5.3 requirement that ‘Fuels shall be free from any material that renders the fuel unacceptable for use in marine applications’. Case 6 - High sediment and acid number readings There have been a number of cases at the end of 2015 where residual fuel from St. Petersburg has been found to contain high levels of sediment and acid numbers (TAN). Total sediment values were found to be in the range 0.30 to 0.50% m/m and TAN around 3.00 mg KOH/g all of which was confirmed by supplier’s analysis. As this was detected in the samples drawn at the time of delivery the shipowner was able to alert the ships concerned to not to use the fuel and initiated claims against the fuel supplier in which they were successful in each case. As such, the fuels were de-bunkered and re-supplied all at the suppliers cost. The downtime for the ships was approximately 6 days and total costs to the supplier were estimated to be around $250,000.

Sludge filled purifier bowl


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Fatty Acids Chemicals M/E A/E M/E A/E

Texas City IFO 380 1.49Hexadecanoic and

Octadecanoic Acids.

Heptanol, Dioxane, Styrene, Phenol, Phenoxy Ethanol,

Trimethylene Norbanane, Phenyl Ethanol, Phenoxy

Propanol, Methyl Benzyl Ether.

Y _ Y Y

Angola IFO380 2.1

Hexadecanoic, Octadeca-dienoic, Octadecenoic and

Tetradecanoic Acids. Isomers of Pimaric & Abietic

Acids.

Butanol, Hexanol, Pinene, Butoxy Butanol, Butyl Acrylate, Traces of

Tetrachloroethylene

Y Y Y Y

Lagos IFO380 2.3

Hexadecanoic, Octadeca-dienoic, Octadecenoic and


Acids.

Butanol, Hexanol, Pinene, Butoxy Butanol,

Butyl Acrylate, Terpenoid Compounds,

Traces of Tetrachloroethylene.

Y Y Y Y

Nigeria IFO380 2.2

Hexadecanoic, Octadecadienoic, Octadecenoic and


Acids.

Butanol, hexanol, A-Pinene, Butoxy Butanol,

Butyl Acrylate, Terpenoid Compounds.

Y Y Y Y

Luanda IFO380 2.35



Acids.

Butanol, Hexanol, Butoxy Butanol, Butyl Acrylate, Terpenoid

Compounds, A-Pinene, 4-Isopropyl Phenol.

Y Y

West Africa IFO380 2.3 Y Y Y Y

Lagos IFO380 0.3

Butanol, Isobutyl Methyl Ketone, Hexanol,

Pinene and Butoxy Butanol.

Y

West Africa IFO380 2.28 Y Y

West Africa IFO380 2.2



Acids.

Butanol, Hexanol, Alpha - Pinene and Butoxy

Butanol.Y Y

Panama IFO500 0.4


Octadecanoic Acids.

Butanol, Styrene, Butoxy butanol, Glycols and Postulated Phenol

derivatives

Y Y Y Y

Client reported fuels system problems subsequently FOBAS identified fatty acids and provided client with a satisfactory explanation. Waiting on feedback from client…..

Vessel encountered serious operational difficulties, FOBAS detected the elevated acid number when tank samples were tested but client did not have representative sample to take the case forward.

Vessel reported heavy sludge at the purifiers, FOBAS identified solvents in the fuel which was considered to possibly be having a cleaning affect in the tanks. Again a contaminant. Waiting for further feedback.

Client reported operational problems on fuel system components . Based on their own and FOBAS experience with such contaminated fuel, they considered further testing unnecessary. Vessel de-bunkered.

Not a FOBAS client but requested us to investigate the quality of fuel after suffering serious fuel pump and injector problems. Vessel had to replace all fuel pumps on main engine.

Vessel suffered damage to fuel pumps and injectors and asked FOBAS to investigate. Finally de-bunkered after suffering problems and power failures in transpacific voyage.

Filter BlockagesFinal Outcome

Vessel suffered severe damage to fuel pumps and injectors and requested FOBAS to investigate, debunkered after contaminants were found in the fuel.

FOBAS alerted the vessel, vessel had no choice but to burn the fuel, suffered damage to fuel pumps and injectors as a sequence vessel also suffered power failure on main engine and generators. Finally de-bunkered.

Reported serious operational problems on fuel system components. FOBAS investigation picked up the contaminants in the fuel. Vessel de-bunkered after supplier confessed the fuel was contaminated.FOBAS alerted the vessel - supplier was put on notice prior to use, vessel had no choice but to burn this fuel. Suffered serious operational problems with fuel system components leading to power failure on main engine and generators

Region Fuel Grade Acid NumberComposition Injector Fuel P/P

Case 7 – Composite of chemical species contamination The following series of cases occurred over an approximate six month period during which 22 ships experience operational problems after loading fuels which, from the basic testing results, had seemingly met the ISO 8217 ordering specification. These fuels however led to severe operational problems being experienced and after extended investigative analysis were found to have been contaminated with a composite of waste chemical species. A number of these cases are detailed below in the table. This series of cases specifically illustrates the incidental vulnerability of the supply chain and how the same sourced fuel stock had ended up being supplied in a number of different locations. The consequence of this contamination was typically the seizure of engine fuel pumps and injectors. The indication that such a problem exists is usually only when it manifests itself on board once put into use– thereafter justifying further investigation and providing the alert characteristics for other ships which have been supplied with the same sourced bunkers to be duly alerted to take precautionary steps.


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Appendix V - A background to marine fuel quality

The use of marine fuels

Since the 1980’s virtually all newbuildings have been motor-ships and therefore these now

represent virtually all the existing fleet. Such ships utilize either low or medium speed engines for

propulsion with additional medium speed engines for other purposes, principally electrical power

generation, together with fired boilers for steam raising / ship services where required.

Through the 1980’s and into the 90’s the objective in many instances was to use the same grade

of residual fuel for both the main (propulsion) and auxiliary (other purposes) engines – the ‘uni-

fuel’ concept - as opposed to using distillate fuel for main engine manoeuvring and the

auxiliaries as was generally previously the case. However, with the advent of sulphur driven

environmental controls, both internationally by means of MARPOL Annex VI and national / local

requirements or incentive schemes, there has been an enforced reversion to have at least two

grades of fuel onboard where ships are intended to operate both inside and outside the areas

where those controls apply.

As to the actual overall quantities of marine fuels delivered world-wide, despite the tonnage of

each delivery being individually documented on the associated bunker delivery note, there are

considerable variations in the estimated total quantities. The IMO 3rd Greenhouse Gas Study

2014, estimated for 2011 the total marine fuel consumption (international + domestic + fishing)

as 253 – 327 million tonnes of which around 75% was given as being residual fuel.

A significant change to the fuel use spectrum has resulted from the reduction of the MARPOL

Annex VI reg.14 Emission Control Area (ECA-SOx) fuel sulphur limit to 0.10 % maximum from 1st

January 2015. While increasing the demand for sulphur controlled distillate grade fuels it has

also had the effect of eliminating the artificially created demand for those sulphur controlled

residual fuels used previously to meet the original, 1.5% maximum, and from 1st July 2010,

1.00%, ECA-SOx fuel sulphur limits. The significance of these sulphur controlled residual grades

in relation to fuel quality in general was the observed tendency for at least some of the lighter

blend stock used in their production to be high in abrasive catalytic fines.

As an alternative to the ECA-SOx fuel requirements a number of ships are now being fitted, at

least in part, with Exhaust Gas Cleaning Systems (EGCS) – otherwise referred to as SOx scrubbers

– enabling the use of residual fuel with the sulphur content typically in the range 2.5 – 3.5 % -

whereas otherwise a controlled sulphur distillate would have been used. However, as yet, the

numbers of these systems in service is not significant as compared to the number of ships which

meet the 0.10% limit on the basis of the fuel as supplied. EGCS as such do not impose any

specific fuel quality criteria other than the sulphur content being within the range of the system’s

capabilities.

Quality requirements

Currently the vast majority of fuels as supplied to ships are and successfully fulfil their intended

role if given the management and applied effort appropriate to the use of an acknowledged ‘not

ready to use’ product and in so doing result in no more than the expected wear and tear on

machinery components. However, at times, more management and effort than normal is

imposed on the user with the risk of, for example, accelerated wear and degradation of

machinery components. In a limited number of cases, prior to use, the fuel quality indicators

available to a shipowner highlight a significant possible risk with a fuel; it then needs to be


February 2016

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assessed whether these can be avoided, or at least mitigated, and if not ultimately whether to

take that risk. In extreme cases the fuel proves itself as unusable; either it cannot be got to the

point of use or having got there results in severe, even catastrophic, failure of machinery –

possibly over the space of just a few hours.

Ultimately fuel is purchased to power the ship, either directly as propulsion power or to power

the various necessary ship services. It is required to do that within the capabilities of an individual

ship; its combustion equipment, fuel system arrangements and components. It is required to

deliver that power in a safe and reliable manner without causing undue wear or operating

problems. As a petroleum product it is to be respected as such in terms of both human health

and fire safety but a particular fuel should not itself introduce additional specific hazards in these

areas. These aspects may be considered as the ‘constants’ of the operating equation.

The fuel, representing the ‘variables’ of this equation, therefore has to be of a certain acceptable

quality at the point of use. However, that quality is multifaceted and not readily defined or

established. Indeed even the aspect of ‘acceptable’ quality is elusive, especially with regard to a

product, which it is accepted from the outset, requires treatment (management in storage,

cleaning and, in the case of residuals, heating) prior to use. What may prove to be acceptable –

and the different understandings of what that may be - in one instance may be found to be not

so in another but in any case that is after the event. To produce a fuel, to order it and to accept

it onboard there needs a prior understanding of what the term ‘quality of fuel supplied’ means.

While a ‘poor’ quality fuel as loaded will, by that definition, be a fuel which results in problems

in service and hence as used, it must also be recognised that an ‘acceptable quality fuel’ as

loaded can be rendered unacceptable at the point of use by actions, or inactions, taken onboard.

The basis of marine fuel as supplied being ‘not ready to use’ may be seen as an historical carry-

over. From the establishment of the diesel engine powered ship (motor-ship) as a general

alternative to the steam powered ship in the 1920’s, these represented generally around 50-

65% , by tonnage, of the ships built each year through to the 1970’s. A core attraction of the

motor-ship being its fuel economy relative to the steam-ship but at the disadvantage of needing

to use a premium ‘diesel’ grade of fuel whereas the steam ship, with a very basic settling and

relatively coarse filter arrangement, could nevertheless readily handle the much cheaper ‘boiler

oil’ fuel grade – the precursor of today’s residual fuel. Hence a principal motor-ship development

and operational objective over this period, which was achieved, was to produce fuel systems and

engines (together with lubricants) which would enable these ships to operate on ‘boiler oil’ and

thereby eliminate that disadvantage.

Hence the marine fuel world – suppliers, purchasers and users – was premised on the universal

supply of ‘boiler oil’, and this has, to date, remained so, despite the subsequent disappearance

of the steam-ship, with the outlooks, systems, equipment and supply procedures appropriate to

such a product grade.

Ready to use at point of supply

While over the years there have been a number of proposals to supply / purchase general

purpose distillate or residual fuels on the basis of being ‘ready to use’ - as is the case with

premium grade distillates - but of course at a price to match, none of these proposals have been

taken up. Indeed it is unlikely given the general outlook that any shipowner would feel so totally

confident in the quality condition of the fuel to be supplied that even having paid for it to be

‘clean’ would feel comfortable in using it without testing to confirm that and still retain the

capability for onboard treatment. Furthermore, there are a number of sources of potential

onboard contamination which would nevertheless still need to be countered – hence the premise

that a marine fuel must be adequately cleaned / treated prior to use will remain, as it always has

been, the case.


32

Technical and commercial aspects of fuel quality

The basis of the specification of the fuel to be supplied will be set by the ship’s known technical

capabilities and intended voyages / areas of operation, the later point reflecting the need to

meet the fuel sulphur limits as given by MARPOL Annex VI or other national / local controls;

either directly by using fuel, as supplied, of the required sulphur content or, where permitted, by

the fitting of approved alternative means such as exhaust gas cleaning systems. A further point

in this is that as engine fuel management systems become more advanced, both in terms of fuel

economy but also for emissions control purposes, potentially they will become ever more

sensitive to poor quality fuels.

In commercial terms it needs to be appreciated that the fuel purchaser and the fuel user may not

be the same entity and therefore could have certain differences in objectives as to the fuel to be

supplied, the ports where it is to be supplied and the particular suppliers to be used. Generally

ships are offered to provide transport services on the basis of either voyage or time charters.

Under a voyage charter the shipowner provides the ship and crew (hence the combustion units

and the persons, engineers, to operate it) together with the required fuel and in turn receives

payment for the goods carried. In contrast, under a time charter agreement a ship is offered on

the basis of a given consumption of a specified fuel grade / quality against speed, and the

shipowner is paid only for providing the ship, and crew; it is the charterer that actually supplies

the fuel to be used.

Hence, in the case of a voyage charter, it is for the shipowner to weigh the odds between the

different fuel supply options on offer considering both the immediate and longer term

implications which may at times result in not taking the lowest cost product on offer and the

preferential selection of a supplier of known performance whereas in the case of the time

charter their core interest is in providing the particular fuel tonnage requirements to cover the

current charter.

By the start of the 1980’s it was apparent to all parties concerned with marine fuel that the

previous practice of referring to product names for distillate fuels and viscosity grades for the

residual fuels no longer provided any guidance as to the quality of the actual product to be

ordered or delivered. To resolve this issue as a joint effort between the oil companies, engine

builders shipowners and others, under the auspices of the British Standards Institution, the first

marine fuel specification was developed, BSMA100:1982. This task was subsequently taken over

by the International Organization for Standardization (ISO) resulting in the first edition of their

marine fuel specification, ISO 8217, in 1987 with revised editions in 1996, 2005, 2010 through

to the current 5th edition of 2012. Over the years new characteristics have been introduced as a

result of the development of the required test methods or an identification of need and certain

limits have been tightened. Under ISO 8217 from the 4th edition onwards it is for the fuel

purchaser to specify the particular sulphur limit to be met.

Despite the onward development of the ISO 8217 specification it is not uncommon still to find

fuels being ordered to the 2005 or even 1996 editions; the particular attraction being the less

stringent catalytic fine and, in the case of the latter, water limits (80 mg/kg and 1.0 % as

opposed to 60 mg/kg and 0.5% for the principal residual grades).

A further point with regard to residual fuels which does nothing to assist in the idea of quality is

the widely used expression that these fuels are ‘refinery wastes / rubbish / garbage’ rather than

being those fractions which at the time and place of production, and with the processes

available, it is not economic to process further. Against this ‘waste / rubbish / garbage’ mind-set

it is not easy to get across into the supply chain ideas such as tank and line cleanliness, avoiding

the ingress of contaminant materials or that such fuels are a convenient, and unnoticed, means

to dump service expired system oils or true waste / slop materials.


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Fuel as supplied – identification of quality

Having identified the ship’s fuel quality, and quantity, requirements and the purchaser having

ordered against those requirements it is for the supplier, in accepting the order, to duly provide.

From the receiver / user’s perspective the first indication of quality will normally be the pre-

delivery documentation provided by the supplier before any transfer commences. At this stage it

must be established that the advised details of the product it is intended to supply are in

accordance with the ship’s requirements, grade and any specific characteristics, otherwise the

product should be refused although the realities of the situation may at times dictate otherwise.

Over the course of the delivery the receiver / user needs to maintain vigilance as to quality

aspects. Are the supplier’s and MARPOL fuel samples being drawn in a manner that indicates

that they will be truly representative and as required? Likewise for the ship’s own drawn sample,

where that is to be taken from a different primary sample to that from which the supplier’s and

MARPOL samples are to be obtained, is that being drawn in a truly representative manner?

Additionally, what other activities are occurring; in the case of a bunker barge alongside is the

operation being conducted without problems, is the barge alongside the sole source or are other

barges pumping through that barge to the ship? Also, does the fuel appear to be supplied as a

homogenous product, has air-blowing been over used, is there any unusual odour or other

apparent abnormal characteristics?

On completion of delivery do the details on the bunker delivery note, in so far as it covers quality

rather than quantity matters, correspond to the pre-delivery data and the ship’s requirements?

Have the supplier’s and MARPOL samples been correctly prepared, documented and securely

sealed as required?

Thereafter it is the shipowner’s choice as to whether they go further and have a sample of the

fuel as supplied tested. For many this now represents a standard part of the quality chain with

that fuel not being brought into use until the relevant test report is available.

Although there have been a number of options over the years for onboard testing from portable

units for individual tests such as viscosity, density and water units through to LR’s ‘Lab-On-A-Ship’

these only provide indications – at times extremely important and highly useful indications (for

example – water reduction across a purifier) – not the basis on which to challenge whether or

not specification limits have been met or to take substantial decisions as to if a fuel should be

considered usable / unusable.

In the first instance for the test results to have any real value the laboratory to be used itself

needs to be accredited to ISO 17025, or an equivalent national standard, for the tests to be

undertaken. While many shore-based test laboratories may have the basic capability to

undertake marine fuel testing a key requirement is that the familiarity and systemic approach to

undertaking the various tests required. This then raises the question of what tests? To simply ask

for ‘... a fuel sample to be tested …’ is an open ended and pointless question.

Today the various fuel testing services all provide standard test packages principally based on the

characteristics given in the ISO 8217 specification; each of which is defined by one or more test

procedures the results from which can then be used to evaluate the fuel as supplied. These fuel

characteristics are reviewed in the attachment at the end of this Appendix.


34

Given the basic framework of ISO 8217, the assessment of quality of a fuel as supplied may be

divided into 3 sub-sets; namely statutory, defined limits and general requirements:

Statutory: From the SOLAS and MARPOL Conventions the particular flash point and sulphur

limits are given – these are set values on which there can be no compromise.

Defined Limits: These would be seen as the numeric limits as given in Table 1 or Table 2 of ISO

8217. These are in respect of certain physical properties, composition or performance indicators.

General Requirements: Ultimately, irrespective of meeting the statutory and defined limits, the

fuel supplied must be fit for use as given by the relevant text clause of ISO 8217 – a requirement

mirrored in regulation 18.3.1 of MARPOL Annex VI which, in that regard, uses the corresponding

text of the 1996 edition of the specification. However, it is quite another matter as to what these

requirements actually represent in terms of characteristics which can be quantified by testing and

furthermore directly linked to predicted or encountered fuel system and engine performance.

Taking this requirement as given in the current (and 2010) editions of ISO 8217 while certain

aspects such as being free of both inorganic acids and used lubricating oil are specified most

other aspects which may render a ‘… fuel unacceptable for use in marine applications …’ – the

presence of certain petro-chemicals and other such contaminants – are not so readily identifiable

other than by specialist, specific, time consuming and costly tests methods – furthermore given

the multitude of possible test methods such testing will normally only be undertaken after a

problem is encountered which itself will be the first clue as to what particular additional testing

to undertake. Even then having identifying an ‘unusual’ component its quantification is another

matter both in absolute terms and relative to other fuels in general – furthermore it is often not

possible to assuredly link that finding to the problem encountered, indeed different engines /

systems may seemingly have used the ‘same’ fuel but with widely differing outcomes. Rather this

is case where if the only factor which changed was the fuel for an engine which has a previous

(and subsequent) history of satisfactory running and it can be shown that all the usual care in

storage, handling and treatment was taken then it by default that it points to the problem being

due to the quality of that particular fuel as supplied.

Additionally both ISO 8217 and regulation18.3.1 of MARPOL Annex VI require:

‘The fuel shall not contain / include …any added substance or chemical waste that:

jeopardizes the safety of ships or adversely affects the performance of the machinery, or

is harmful to personnel, or

contributes overall to additional air pollution.’

In the context of what is often a multi-stream blended product there is the issue of how is ‘... an

added substance …’ defined, what is ‘.. a chemical waste…’ given that in many instances a by-

product from one refinery or industrial process is the feedstock to another – and that, as

highlighted above, many in the industry already see residual fuels actually as being waste

materials. What is the test of the term ‘... jeopardizes the safety of ships …’, what constitutes ‘..

an adverse effect …’ given that a ship is as a matter of course to be operated in a safe and

prudent manner and marine fuels are ordered, purchased and supplied on the basis of requiring

adequate cleaning / treatment prior to use. While some extreme cases of poor fuel quality – at

the point of supply - could be seen as clearly breaching one or more of the listed requirements,

for the majority of cases of questionable fuel quality these criteria would not be readily

established or proven.

As to effects on human health, as a hydrocarbon product a marine fuel will have inherent safety

issues in terms of being a combustible product, a source of hydrocarbon vapour and human

contact / ingestion. Exactly where these depart from the ‘norm’ – however defined – and how


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that is established and where the degrees of responsibility lie between the supplier and the user

(or both) differs considerably.

Finally, in terms of air pollution it is unclear what is implied by the term ‘... overall ...’ – where are

the boundary lines of this assessment, solely onboard or taking into account some or all of prior

extraction, transport and production activities – and how are the relative demerits of the various

disparate effects of combustion products aggregated to arrive at any such assessment?

Consequently, given the above the question of the real-world quality of the fuel as supplied to

the ship may be considered as a two part question:

Criteria 1

Has the fuel met the ordered specification? In the case of ordering against ISO 8217

have the relevant statutory and defined limits been complied with? but recognising that,

in terms of the ‘acceptable for use’ aspect, the certain aspects of this point will normally

only be capable of assessment only after the fuel has been brought into use.

Criteria 2

Where the fuel has not met one or more of the statutory or defined limits then does that

render the fuel unusable or, with a certain amount of effort, to the particular points

identified it could be used without undue risk?

This two part distinction is important since there is, in practical terms for the ship, also a time

dynamic – hence the responsibility on the supplier, not the receiver, to ensure the quality of the

product delivered. The fuel a ship receives is only that fuel which comes down the bunker supply

hose. From the receiver’s / ship owner’s perspective, pre-delivery inspections and the like are

generally not seen as practical or having any real value. Where for the receiver’s own information,

fuel testing is to be undertaken a worthwhile representative sample can only be drawn over the

whole of the supply period. Consequently, the fuel will always be onboard before it can be

assessed; typically by despatch of a sample to one of the fuel testing services and as that takes

time a ship will normally have sailed from the port of supply before the quality of the fuel

received is established, at least in terms of the statutory and defined limits.

Even where that is not the case, for example where there is a problem identified from the

information given on the bunker delivery note, bunker supply barges can pump at rates of up to

so many hundred tonnes an hour whereas a ship’s installed transfer pumps in most instances can

pump at only a fraction of that rate. Therefore no fuel once onboard is readily off-loaded – even

where there is supplier agreement. Added to which any quality dispute process will, given the

financial and other implications, take time to resolve and will not necessarily conclude with the

fuel being off-loaded and also that is time during which time the ship’s fuel storage capacity is

reduced, possibly substantially, by a fuel which is not at that time available for use.

Indeed while a fuel supplier may, having been alerted to the issue by the user, agree that a

particular fuel has failed an aspect under Criteria 1, as given above, the real-world resolution of

that is more often financial – a discounted price being instead charged, rather than actual de-

bunkering. As to whether that discount actually covers the time, direct and indirect costs

together with the fact of the shipowner having to take on an additional risk burden for a fault

not of their making is another matter.

A further consideration in this area is that a particular consignment of fuel may, on receipt or

later, have been comingled in storage tanks onboard the receiving ship. Good practice guidelines

stress that fuels should always be loaded into tanks which have been emptied of previous fuels

however in reality this is often not possible; either in the case of being required, by the owner or

charterer, to load maximum bunkers or in the case of distillates where there may be only a

limited number, possibly only one, storage tank. In those instances a fuel which has failed the

Criteria 1 requirements will inevitably affect the fuel with which it has been mixed. While the


36

supplier, in potentially accepting that the fuel they supplied did not meet the specification

requirements, will take no responsibility for other fuels already onboard which have been cross

affected.

Therefore, in all but the most extreme cases, off-loading a fuel which has been found to fail the

Criteria 1 requirements is not the optimum outcome for any of the parties involved. Added to

which the ship will invariably have departed from the port of supply before any agreement to

off-load is concluded there is the question of not only the physical arrangements but also who is

to receive that fuel and its product status as a ‘unacceptable’ quality fuel.

Fuel quality characteristics and the significance of off-specification test results

The following table provides a brief on the potential significance of the various characteristics

specified in ISO 8217:2012 Tables 1 and 2 and those others characteristics which fall under the

general requirements and Clause 5, when off-specification. In this context, off-specification

means an instance where the test result obtained exceeds a maximum value, or is below a

minimum value, by more than the 95% confidence margin given by application of ISO 4259. It

should be noted that this is not an exhaustive list but rather provides an indication of some of

the possible outcomes of an off-specification product being supplied to a ship.

Characteristic Significance Implications of off-specification

FAME FAME – Fatty Acid Methyl

Esters otherwise known as

‘bio-diesel’ – not to be used

as an intended blend

component.

Concern that FAME of significant content may result

in:

a) oxidation stability problems with resulting

formation of sediments which can choke filters and

fuel injection components, particularly if stored for

extended periods;

b) finely dispersed water within the fuel which may in

turn promote microbial problems;

c) depending on source material may have poor low

temperature performance characteristics;

d) FAME material deposition on exposed surfaces

including filters; and

e) degradation of certain resilient type seal materials.

Inorganic acids Also known as ‘strong acids’. Fuels to be free of these highly corrosive acids (i.e. sulphuric acid, nitric acid, hydrofluoric acid).

Corrosion attack particularly to purifier and fuel pump and injection system components.

Used lubricating oils

See below See below


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Distillate fuel – ISO 8217 Table 1


Viscosity at 40˚C

Ease of flow Values above max limit: tendency to compromise injection spray pattern. Increased mechanical load on fuel pumps and drive arrangements. Values below min limit: potential that there will be insufficient dynamic lubrication under higher temperature conditions. Increased tendency to flow through fine clearances, particularly under the high pressures of fuel injection pumps, especially where those clearances are wear increased resulting in an inability to generate the required pressure / flow. Also shortfall of spray penetration on injection.

Density at 15˚C Weight / volume relationship of a fuel

Selection of appropriate purifier gravity disc. Reduced tendency to settling out of water and solids. Also as density is generally used to convert the delivered quantity (m

3) into the invoiced amount

(tonnes), a value below the quoted bunker delivery note value results in a tonnage shortfall.

Cetane index Ignition performance of base fuel.

Does not take into account any ignition performance additive which may have been applied. Values below minimum limit increasing potential for extended ignition delay (hence knocking which can damage top and bottom end bearings) particularly under low load or cool charge air conditions.

Sulphur Precursor of post combustion low temperature corrosion of susceptible components in engine and exhaust duct. For environmental protection controlled to limit SOx and related particulate emissions.

Statutory issue. Non-compliance with MARPOL Annex VI regulation 14 (and / or local controls). Increased tendency to cold corrosion.

Flash point Temperature at which fuel vapour is ignited under specific closed cup test conditions.

Statutory issue. Non-compliance with SOLAS. Values substantially below minimum limit could indicate inclusion of particularly volatile components with potential for evolution of hydrocarbon rich vapours.

Hydrogen sulphide

Indicator of fuel’s potential capability to evolve toxic harmful vapours.

Increased risk of evolution of harmful vapours during storage, transfer and treatment. Formed in the refinery process it is normally negligible in the fuel as supplied. However awareness and appropriate precautions must be always taken when handling marine fuels. The limit provides a margin of control to exposure but does not eliminate the risk entirely from within enclosed spaces. Appropriate safety processes and procedures should be in place to protect crew and others at risk to exposure. In extreme cases exposure to accumulations of the vapour phase would be fatal.

Acid number Indicator of acidity however no direct correlation between acid number and corrosion risk.

Possibility of an indication of corrosive and or lacquer forming chemical species degrading susceptible components particularly fuel injection equipment however some crudes naturally result in elevated values which do not give rise to in-service problems.


38

Total sediment – existent (DMB)

Quantification of filterable material present. Indicator of whether, in a fuel incorporating residual material, the blend components are compatible.

Increased sediment in tanks (particularly settling tanks) and during treatment (purification and filtering). If fuel is not a blend of compatible components the resulting asphaltenic sludge precipitated will affect treatment effectiveness and may potentially result in choking of the system and or irregular combustion profile.

Oxidation stability

Tendency to form gums and resins over time.

May be due to unstabilised distillate type products but also potentially due to inclusion, by intent as a blend component or inadvertently due to line washing / remainder in tanks, of poor quality FAME / biodiesel with therefore particular tendency to other FAME related problems. Resulting gums and resins acting to result in choking and interfering with free movement of sliding components.

Carbon residue (DMB)

Indicator of tendency to post combustion carbon deposition – engine design and operating profile dependent as to significance.

Tendency to increased post combustion carbonaceous deposits in engine, system lubricant, turbochargers and in exhaust duct particularly under low load or other non-optimum operating conditions. Potential for cracking of fuel in uncooled injector tips resulting in hard carbon deposits being formed which compromise combustion by adversely affecting injector spray pattern resulting in further deposition.

Carbon residue – 10% residue (DMX, DMA, DMZ)

As above but on a concentrated fraction of the sample – test result is not a tenth of what would have been obtained if using full sample.

As above.

Cloud point (DMX)

Temperature at which wax crystals are first evident on cooling.

If operating at temperatures where there is at least a proportion of the wax component of a fuel in a solid condition, albeit dispersed, it will tend to choke filters and other fine clearances.

Pour point Lowest temperature at which fuel is still fluid under test conditions.

A fuel once solidified is of course unpumpable and furthermore is not readily brought back to a liquid condition by subsequent heating due to having a very poor heat transfer characteristic. If not possible to await return to warmer ambient conditions fuel may literally have to be dug or stream lanced out of tanks and transfer lines physically rodded through / dissembled in order to remove. Fuel in tanks with surfaces exposed to ambient (water or air) temperatures below the pour point may form a solid mass on that surface which can grow to the point where it breaks away to fall through the liquid phase as a solid mass and so choke suction connections. For distillate fuels however pour point is only one element of low temperature performance since problems due to wax precipitation can be encountered at temperatures significantly above the pour point as indicated by the Cold Filter Plugging Point test (the temperature at which flow is blocked in a test rig using a standard filter element) – a characteristic which is not currently restricted in Table 1.


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Hydrocarbon waxes exist in a multitude of differing forms each with its own solidification temperature and therefore the problem arises when a sufficient number and quantities of these waxes have precipitated such as to choke filters and any other fine clearances. Given the ranges and concentrations of the different wax species which may be present in a particular fuel together with the different sensitivities to filter choking there is no set value above the pour point at which this wax precipitation will cause problems – it may be a only 1 or 2˚C or it may be more than 20˚C. This issue is addressed in greater detail in the CIMAC Guideline for Managing Cold Flow Properties of Marine Fuel.

Appearance (DMX, DMA, DMZ)

If clear and bright fuel is taken as water free. For excise purposes some marine distillates may include dye which affects the ability to assess the appearance.

If not clear and bright the total sediment and water tests need to be undertaken – if water present in significant quantity issues as given in following entry. Oxidation stability and lubricity tests cannot be undertaken.

Water (DMB)

Contaminant material – can be from fresh to saline.

Contaminant material indicative of poor storage and / or handling conditions. If saline or brackish there will be a corresponding sodium content. Potential source of bacterial contamination particularly at the oil/water interface where water collects at the base of settling tanks. Lowers fuel energy content.

Ash Distillates should be generally free of ash forming components.

Indicative of presence of extraneous material. Further investigation required to determine particular nature of that material, often caused by contamination by residual fuel oil with its higher concentration of metals.

Lubricity (fuels < 0.050% sulphur)

Ability to support boundary lubrication between contact surfaces.

Wear / micro-seizure between contacting surfaces.


40

Residual fuel – ISO 8217 Table 2


Viscosity at 50˚C

Ease of flow Higher than expected temperatures required for transfer and injection however due to the viscosity / temperature relationship values significantly higher than limit value result in only limited increases in required temperatures (ie 500 cSt as compared to 380 cSt increases transfer and injection temperatures by around 3˚C and 6˚C respectively). Higher than recommended injection viscosity may result in poor atomisation and overloading of fuel injection feed pipes

Density at 15˚C Weight / volume relationship of a fuel.

Decrease in the density differential which is the basis for cleaning by settling or purification / separation, even to the point where there is no differential with water which will not therefore be reduced. Conventional purifiers with a nominal density limit of 991 kg/m

3 should be able to function with fuels up to

around 994 kg/m3 although less efficiently. Modern

separators, without conventional gravity disc, can however operate up to around density values of 1010 kg/m

3.

Also as density is generally used to convert the delivered quantity (m

3) into the invoiced amount

(tonnes) a value below the quoted bunker delivery note value results in a tonnage shortfall.

Calculated Carbon Aromaticity Index CCAI

Principally included to control the fuel’s viscosity / density relationship and hence preclude unconventional blends. Also empirical indicator of ignition performance.

Tendency to indicate ignition problems more pronounced with lower viscosity fuels but low speed and most medium speed engines not generally oversensitive to such issues. For some higher viscosity grades this may be a factor which sets blending limits. High values result from atypical viscosity / density relationship which, for the lower viscosity fuels in particular, may indicate use of unusual blend components. CIMAC has published their recommendations ‘Fuel quality guide – Ignition and combustion’ which gives further details.

Sulphur Precursor of post combustion low temperature corrosion of susceptible components in engine and exhaust duct. For environmental protection controlled to limit SOx / particulate emissions.

Statutory non-compliance with MARPOL Annex VI regulation 14 (and / or local controls). Increased tendency to cold corrosion.

Flash point Temperature at which fuel vapour is ignited under specific closed cup test conditions.

Statutory non-compliance with SOLAS. Values substantially below min limit could indicate inclusion of particularly volatile components with potential for evolution of hydrocarbon rich vapours.

Acid number Indicator of acidity however no correlation between acid number and corrosion risk.

Possibility of corrosion of susceptible components particularly fuel injection equipment however some crudes naturally result in elevated values which do not give rise to problems.


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Total sediment - aged

Quantification of filterable material present. Indicator of whether a fuel is a blend of compatible components and / or will remain in a stable condition over time or on heating.

Test method has a relatively high (0.05) 95% confidence margin relative to the limit value (0.10). In addition off-specification values often found to be due to toluene insoluble material and hence in those instances not indicative of asphaltene instability. As a straight filtration test it is indicative of possible increased sediment in tanks (particularly settling tanks) and during treatment (purification and filtering). However, if fuel is not stable the resulting asphaltenic sludge precipitated will seriously adversely affect treatment effectiveness, resulting in excessive sludge precipitation and hence choking of the purifier and filters. Coke formation on heater elements restricts heat transfer and therefore it may not be possible to achieve the required injection temperature. On injection the sludge will not be sufficiently atomised resulting in impingement on liners and hence cracking, heavy fouling which can impede required action of piston rings and choke turbocharger turbine blades.

Carbon residue Indicator of tendency to post combustion carbon deposition.

Possible increase in post combustion carbonaceous deposits in engine, system lubricant, turbochargers and in exhaust duct particularly under low load or other non-optimum operating conditions.

Pour point Lowest temperature at which fuel is still fluid under test conditions.

Since most residual fuels require heating (30-40˚C) in order to achieve the required transfer viscosities there is usually the tank heating capability to deal with this issue, provided it is used as required. A fuel once solidified is of course unpumpable and furthermore is not readily brought back to a liquid condition by heating due to very poor heat transfer characteristic.

Water Contaminant material – can be from fresh to saline.

Contaminant material indicative of poor storage or handling conditions. If saline or brackish there will be a corresponding sodium content. Potential source of bacterial contamination particularly at the oil/water interface where water collects at the base of settling tanks. Water should normally be capable of being significantly reduced by onboard treatment if in other than a finely emulsified state. Water content remaining in the fuel as used can result in micro-seizure of fuel injection components and also lowers the fuel’s energy value.

Ash Summation of all ash forming materials present.

Fuel ash may be due to elements present in the crude stock used and which are concentrated into the residual fraction, elements introduced during refinery processes such as catalytic cracking and which are not recovered prior to release to the residual pool or elements present due to extraneous contamination. Further investigation of cause of high values necessary and on identification due action, if possible, taken.

Vanadium Precursor of post combustion high temperature corrosion to susceptible components.

Unaffected by onboard treatment. High temperature corrosion only occurs if the component surface temperatures are sufficiently high for at least some of the various vanadium compounds which may be formed to deposit in a semi-plastic state in which case the higher the vanadium content the more


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severe the problem.

Sodium Precursor of post combustion high temperature corrosion to susceptible components and deposit formation. Indicator of saline water contamination.

Although treatment may reduce the water and associated sodium content where that is saline (or in case of evaporative loss) some sodium will be retained in the fuel. This lowers the temperature at which vanadium compounds will deposit on engine components. Additionally, the sodium sulphate will contribute to the other ash forming metals and can result in fouling of the turbocharger turbine blades reducing its performance – in the extreme to engine failure.

Aluminium + Silicon

Indicator of abrasive catalytic fine material being present.

High levels of aluminium + silicon (catfines) are not easily reduced during normal on board treatment and can therefore pass through to the engine fuel system where rapid wear of injection system components (fuel pumps, injectors), liners and piston rings may occur. Piston rings so worn down can break up with the resulting debris causing further extensive damage to the combustion chamber components and turbocharger turbine.

Hydrogen sulphide

Indicator of fuel’s potential capability to evolve toxic harmful vapours.

Increased risk of evolution of harmful vapours during storage, transfer and treatment. Formed in the refinery process it is normally negligible in the fuel as supplied. However awareness and appropriate precautions must be always taken when handling marine fuels. The limit provides a margin of control to exposure but does not eliminate the risk entirely from within enclosed spaces. Appropriate safety processes and procedures should be in place to protect crew and others at risk to exposure. In extreme cases exposure to accumulations of the vapour phase would be fatal.

Used lubricating oils

Indicator of inclusion of waste products which could include other not readily detected deleterious materials.

Waste lubricating oils are generally collected in an uncontrolled manner and therefore such wastes can also include a wide range of other materials such as hydraulic oils, solvents and other cleaners all with unpredictable results in terms of fuel treatment and combustion performance.

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Contact: Timothy Wilson Principal Specialist Fuels (FOBAS) Lloyd’s Register EMEA Lloyd’s Register Global Technology Centre, Southampton Boldrewood Innovation Campus, Burgess Road, Southampton,SO16 7QF T 44(0) 33041 40570 E [email protected] W www.lr.org/tid

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Copyright © Lloyd’s Register EMEA. 2016. A member of the Lloyd’s Register Group.

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