Fuel Additives & Fuel Blending

Part ofMarine Fuels Webinar Week29 June-3 July 2020

Webinar Q&A summary:OD’O | Oliver D’Olne, AdercoJL | John LaRese, ExxonMobil Marine Fuels

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What is the blending ratio for the Aderco product?

OD’O | 1 Liter for 55 metric tonne.

Aderco claims that this product 2055G is also a combustion catalyst ...how is this possible if it does not contain any of the metallic catalysts required for

combustion improvement?

OD’O | Aderco 2055G is a highly concentrated surfactant reducing the surface tension between hydrocarbon molecules within the fuel matrix. The

reduction of surface tension during the injection phase allows for a reduction of the size of fuel droplets. Therefore, for a same quantity injected, you get a

finer mist of fuel droplets, increasing the contact surface between air and fuel. A higher surface of contact helps to a full combustion process.

If additive is necessary then surely the supplier should add it and not the buyer?

OD’O | It is preferred that the end-user doses the product in their tanks. The reason why is explained by the polarized nature of Aderco 2055G surfactant. A

fraction of the product will be lost for fuel treatment by sticking to the metal surfaces of the tanks. When you dose on shore then you transfer to a barge

then you transfer to the vessel tanks, you will lose three times this "sticking" fractions, with a potential of losing the full fuel treatment properties.

JL | ExxonMobil fuels delivered into-ship do not require additives, and it is our opinion that any reputable supplier should be responsible for ensuring that

marine fuel not only meets the purchasing specification, but is fit-for-use as well. However, if the fuel purchased from others is lacking in certain qualities,

additives may be recommended to improve these shortcomings.

Does Exxon test all their fuels by FIA?

JL | During the development of our fuels we undertake a thorough fit-for-use assessment which includes additional testing above and beyond the standard

ISO 8217:2017 characteristics. Some of these tests consider combustion, waxing, compatibility and other parameters prior to manufacturing and releasing

our product. Additional, periodic assessment includes test bed engine testing and onboard vessel trials to ensure our products are of the highest quality

and performance.

It is very difficult to treat on-board after the fuel has been bunkered. Would you recommend treatment on-board once the fuel has been stemmed?

OD’O | Recommendation is to dose the tanks before bunkering, once the quantities of bunkers are confirmed by the supplier. It is always possible to dose

past bunkering.

Does this fuel comply with IMO 2020?

OD’O | Cannot reply as our product is not a fuel.

JL | ExxonMobil’s EMF.5TM IMO compliant (max 0.50% sulphur) fuels meet or exceeds ISO 8217:2017 specifications and is compliant within IMO’s 2020

0.50% sulphur limits.

ISO 8217: 2017 do not include a spec. specific for VLSFO. When will a dedicated ISO spec be delivered?

OD’O | Not before 2022, the latest revision was in 2017. The ISO 8217 board revise every five years. However, no idea if a new category will be introduced.

JL | The ISO 8217:2017 specification for Residual Fuels does not list a limit for sulphur due to different requirements in different locations. The specification

applies to all sulphur grades. The ISO working group, of which ExxonMobil is a member, is in the process of developing the next edition of ISO 8217 with

industry-recommended changes.

Is there any effect on fuel consumption after using of an additive?

OD’O | Yes see just above.

Re: low viscosity VLSFO (Category1 as per Aderco slide): what is the recommendation on handling such bunker onboard? For example, the bunker has

been received, the bunker sample analysed in laboratory showed about 30 cSt. Can we use additive at this stage

OD’O | We recommend to treat on a continuous basis. But if you opt for treating only low viscosity fuels, then you simply apply the normal dosage 1 litre

per 55 Mt, before bunkering.

Did you gather fuels from around the globe? How many different fuels did you conduct these tests on?

OD’O | Fuel samples collected at various major port like ARA, Houston, Singapore represent the general trend of VLSFO you get in these major ports.

What is your view on the stability reserve of the VLSFO's? We have seen cases where the TSP of the specific product was on-spec testing directly after

delivery while when treated/consumed after a short period of time seemed to have deteriorated rapidly, c

OD’O | This case of abnormal ageing of VLSFO's have been noticed mainly with low viscosity paraffinic fuel oils. Our view is the rapid oxidation of blend

components like Vacuum Gas Oil (VGO) explain this new issue.

JL | The development of the new fuels ahead of IMO 2020 has resulted in a large number of fuel types and a variety of different sediment levels have been

reported. This is commonly caused by the fuel’s stability. Fuel should be able to remain onboard for six months minimum without degradation which would

render the fuel unfit for use. Vessel operators should have a conversation with their fuel supplier if they suspect the fuel has started to break down in a

short period of time.

Olivier, does your product influence the separation efficiency of the separators in any way? For example, do separation times or separation

temperatures have to be specially adapted?

OD’O | No adaptation of temperature or separation times needed. The separation efficiency is the result of an optimum fuel homogenization in fuel

storage tanks, better drainage of sediments and water at settling tanks. Also, the reduction of surface tension improves the ejection of cat fines and

sediments.

Jörg Ullmann , Bosch: Could you comment on temperature and pressure influence on asphaltene precipitation. Little is known about the effects in

booster pumps

OD’O | Asphaltene precipitation and mainly driven by temperature, but for sure pressure will be an added factor for contributing to asphaltene

precipitation in booster pumps. The principle of our fuel treatment is to coat the asphaltene molecules with a protective layer, especially when this resin

protective layers have been damaged (mainly in refinery with heavy cracking processes).

JL | Typically, asphaltenes drop out in storage and settling tanks and not in fuel systems. The fuel stays in the fuel system for a relatively short period of

time and there is little tendency for fuel separation during this period. The biggest effect on asphaltene drop out is the overall solvency reserve of the fuel,

keeping those molecules in suspension. The degree of solvency reserve of the product is one aspect of the problem, the other is the total amount of

asphaltenes present. If solvency reserve is an issue, a high asphaltene content will make a bad situation worse.

Will Aderco 2055G help with wax appearance that John discussed?

OD’O | Our product has no action so far as we know on wax crystals.

What are the treat rates of 2055G used to generate the results presented in the Olivier's slides?

OD’O | The treat rates used in the laboratory testing take into account the surface area to volume principle, in summary the treat rates are not the same as

for traditional dosing but it is in relation with the small size of containers used in labs. Translated, it means a dosage of 1Ltr for 55 Mt.

Recently, we have received fuels with a high CCAI. Can Aderco assist with this?

OD’O | High CCAI are abnormal for VLSFO. Normally the VLSFO's should have a CCAI in the region of 800 - 825. This CCAI is a computation made with an

algorithm. It does not always represent the exact combustion quality of your fuel oil. However, for the reasons explained above - better combustion

through a finer atomisation of fuel droplets can be obtained with 2055G, improving indirectly the CCAI.

Is Heavy Aromatics with 2-5ppm sulphur good as a blending component for bunkers?

OD’O | They are a good candidate for blending as their calorific value is high, but they must be adjusted finely in order to not exceed the final cap of 0.5% in

the finished blend.

JL | One component cannot be evaluated on its own, you would have to look at the entire component mix to determine if the different components are

suitable to be blended together.

Can Aderco 2055G positively influence TSP/TSA, S value and P value tests as referenced by CIMAC as acceptable tests for fuel stability and compatibility?

OD’O | TSP and TSA can be improved with Aderco 2055G. In fact it is one of the main advantages of using 2055G, to improve fuel stability by keeping

asphaltene in suspension and preventing it from coagulating. Our product has also the ability to disperse existing agglomeration of asphaltene and this

helps to reduce the TSP and TSA. However, some limits must be set for this improvement. Abnormally high TSP as we have seen this year, four to five time

the upper limit, cannot be brought down to acceptable levels.

Can smaller cat fines pass through a well operated purifier?

OD’O | This is always the issue, small cat fines are the most difficult to eliminate and even with a perfect setting, a fuel oil separator can eject up to 75% of

cat fines but not more. So any additional input like the use of 2055G for improving cat fines drainage and ejection will be a bonus.

JL | Yes they can. It is imperative to ensure that all aspects of a ship’s treatment system are working correctly. This includes proper housekeeping to

ensure water is drained off of fuel tanks daily to assist cat fine settling, proper temperature in storage and settling tanks to aid settling. Proper purifier

operation and keeping a low as possible throughput to maximize the time fuel remains in the purifier bowl, which will maximize the separation. Ensure that

fine micron filters just before engines are fitted with the proper mesh size. In some cases cat fines are extremely fine (small) particles sizes that will pass

through these fine mesh filters and still enter the engine.

When is the optimum time in the supply chain to treat with Aderco 2055G?

OD’O | The end user is the optimum place, I have explained above the reason why. There is a loss of product each time you transfer a treated fuel oil from

one tank to another.

Question for John; what about the asphaltene instability of VLSFO and potential to cause combustion-related asphaltene deposits?

JL | Typically, the biggest worry is the solvency reserve of the fuel and the drop out of asphaltene molecules causing increasing levels of sediment. If this

gets severe it can cause excessive purifier sludging and filter blocking. Look at the analysis of your fuels for contaminates such as vanadium, sodium, ash

etc, that are more indicative of potential problems with deposits.

Did Olivier explain the relationship between "reserve stability number (RSN)" and TSP? Can you repeat to clarify?

OD’O | TSP and RSN are linked. TSP is a quite rough indicator of the fuel stability; RSN is a much more precise measure for the same stability issue. Some

companies order systematically RSN analysis for each FOA. This helps to take emergency action with our product if something wrong is detected.

Emergency action means increasing the dosage as soon as RSN exceeds 10 (range 1 to 15).

Why don’t engine makers implement common rules and designs, so that all engines become compatible with standardised fuels in the market?

OD’O | The engines receive at injection phase the fuel that was bunkered and the quality can fluctuate a lot. When engine manufacturers make their tests

in their facilities, they use a standard and well-blended fuel oil which does not always represent the real-life bunker. It is especially difficult for a

manufacturer to replicate this fuel oil diversity in quality and specifications. This is the reason why it is essential to keep a good fuel-handling procedure on

board, for instance limiting fuel commingling of different viscosities as much as possible.

JL | With the advent of IMO 2020 and the 0.50% sulphur cap there is a wide variety of fuels that have entered the market. Most all of these fuels meet the

intent of the spec and do what they are supposed to do and are fit to use. However, they might require vessel operators to change how they operate the

engine, i.e. lower load similar to when operating an engine on gas oil compared to a residual fuel. ExxonMobil works closely with all the major OEMs to

ensure that the fuels, lubricants and cylinder condition monitoring ensure that the engines work at their optimum level.

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