Lloyd’s Register Fuel Oil Bunkering Analysis and Advisory Service (FOBAS) on Thursday (8 May) released a bulletin regarding its testing on a number of fuels that have a high tested Ash content, above the 0.100%m/m limit for an RMG380 grade:

In recent days FOBAS has tested a number of fuels that have a high tested Ash content, above the 0.100%m/m limit for an RMG380 grade. These fuels were bunkered in the second half of April from ports in the ARA (Antwerp, Rotterdam, Amsterdam) region with tested Ash ranging from 0.102 to 0.127%m/m.

These fuels are all high sulphur residual fuels (>0.50% mass) with very similar properties and appear to be from the same source.

One common factor in all is the high Calcium which is a main contributor to the off-spec Ash in each case. Calcium ranged from 116mg/kg up to 181mg/kg. Sodium was also relatively high ranging from 50 to 86mg/kg., The fuels also had high acid numbers (TAN) ranging from 2.20 to 3.40mgKOH/g.

Often when we see high acid numbers (>2.00mgKOH/g) and high Calcium together this is due to naphthenic acids. These are present in the original crude oil and generally not considered any operational concern. Initial testing on some of these recent fuels show naphthenic acids to be present.

There are some additional points to clarify on the above:

• Firstly, in relation to Calcium, it may be noted that ISO8217 lists a 30mg/kg limit for Calcium. It is important to note the full clarification in the standard however, where the Calcium limit only applies in conjunction with the Phosphorus or Zinc limits of 15mg/kg, used as a measure of ULO (Used Lubricating Oil) presence, rather than to limit the Calcium content on its own.
• Sodium levels, although relatively high are all still below the 100mg/kg RMG380 grade limit.
• On any high acid number fuel, it should also be noted that just because naphthenic acids are present, it does not rule out any other contamination or potential issues with the fuel. Additional attention should be given to the performance of the fuel injection equipment and component conditions during the use of such fuels
• Although Calcium on its own is not a problem, at high levels where it increases the total Ash content as seen here, it can be an issue with increased Ash potentially leading to an increase in post combustion fouling and surging of turbocharger. This should not be allowed to accumulate in particular in the turbocharger, inlet grids, nozzle and blading.

So far we have not had any operation problems reported on the use of these fuels, however caution should be taken in particular to dealing with any increase in post combustion fouling as mentioned, and if further investigation into the nature of the acidic components present is required to confirm they are only naphthenic acids then detailed GCMS forensic testing could be carried out.

Photo credit: Louis Reed from Unsplash
Published: 9 May, 2025

Lloyd’s Register Fuel Oil Bunkering Analysis and Advisory Service (FOBAS) on Tuesday (29 April) released a bulletin regarding testing of fuel samples from different vessels, which bunkered in Istanbul, that have reported problems with fuel injection equipment seemingly caused by a substance sticking and seizing the jerk type fuel pumps:

In recent days, FOBAS has tested fuel samples from different vessels that have reported problems with fuel injection equipment seemingly caused by a substance sticking and seizing the jerk type fuel pumps. These vessels bunkered fuel in March and April this year from Istanbul.

These fuels have been further investigated with extended chemical analysis showing a number of chemical species present with some at very high levels.

Various chemicals were found including 4-Cumyl Phenol and Cyclohexane Diol at high levels. Resin acids and Acrylates were also identified along with unusually high levels of DCPD (Dicyclopentadiene), Indene and trace levels of Tetrachloroethylene.

Not all these chemicals may be contributing to the problems, but they are in a pattern seen in some problem fuels from Antwerp and Rotterdam in 2024 and a number of problem fuels from Houston in 2023 and 2018. Some of these chemicals can polymerise and are used in the manufacture of resins and plastics and may be reacting together under the heat and pressure of the fuel injection system.

These fuels were found to be on-spec based on standard routine analysis. However, there are some particular parameters of note. Viscosity was low at around 40cSt, acid numbers were high (1.50 – 2.50mgKOH/g) and all fuels were VLSFO with sulphur content <0.50%. This low viscosity and high acid number pattern aligns with other contaminated fuels seen in Houston in 2023).

We would suggest that if you have bunkered in the last 2-3 months in Istanbul to be particularly cautious with the use of the fuel. In particular if the fuel has a low viscosity, around 50cSt or lower, high acid number >1.00mgKOH/g or high sediments, we would suggest to discuss further testing options as this problematic fuel may not be isolated to only two vessels.

It should also be noted and suppliers reminded that any fuel purchased against the ISO8217 standard must meet the general requirements of clause 5 as well as limits in the characteristics tables. Clause 5 includes the statement that the fuel should be a “homogeneous blend of hydrocarbons derived from petroleum refining” and be free from any substance or chemical waste that “jeopardizes the safety of the ship or adversely affects the performance of the machinery”.

Photo credit: Hans Reniers on Unsplash
Published: 30 April, 2025

Lloyd’s Register Fuel Oil Bunkering Analysis and Advisory Service (FOBAS) on Friday (11 April) released a bulletin regarding its testing of several samples of high sulphur residual fuels from Civitavecchia withTotal Sediment Potential (TSP) results exceeding the ISO8217 specification limit of 0.10% m/m:

In recent days, FOBAS has tested several samples from Civitavecchia with Total Sediment Potential (TSP) results exceeding the ISO8217 specification limit of 0.10% m/m. The samples were all high sulphur residual fuels and TSP results ranged from 0.83% m/m to 1.05% m/m.

Further analysis on these fuels suggests a possible mix of both asphaltenes and some extraneous dirt.

Fuels with high sediments can result in excessive sludge deposition in tanks and throughout the handling and treatment/fuel injection systems.

In view of the above, if your ships are planning to bunker in this port, we recommend that suppliers are advised of your concerns regarding the stability of the fuel in the area, and that they provide you with additional reassurance that they will adhere to the ISO 8217 requirements for the grade ordered. Ideally including providing full TSA, TSE and TSP sediment test results.

Additional attention should be given to the collection of bunker samples. It should be ensured that all parties have witnessed the sampling process and have signed witness forms accordingly, and that the supporting documentation includes records of all the samples considered representative of the fuel as loaded.

Photo credit: Louis Reed from Unsplash
Published: 14 April, 2025