Bunker Flash

FINDINGS & INSIGHTS

During the period of 25 July 2025 to 02 August 2025, Maritec Pte Ltd (hereafter referred to as Maritec-Naias) tested forty samples representing VLSFO deliveries from various suppliers at Singapore ports, which indicated Aluminium and Silicon (Al+Si) concentrations ranging from 51 mg/Kg up to 120 mg/kg.

Maritec-Naias findings of Al+Si concentrations in the forty samples tested were as follows:

• Two samples indicated Al+Si concentrations above 100 mg/Kg levels
• Eleven samples indicated Al+Si concentrations above 60 mg/Kg levels
• Twenty-nine samples indicated Al+Si concentrations between 51 to 60 mg/Kg levels

While thirty eight out of forty samples fell within the specifications of ISO8217:2005 (80 ppm) and even within the ISO8217:2010/2017 specifications (including permitted limits of 72 PPM as per ISO4259 for a single test result), the Catfines content can still be considered at high levels.

Aluminium and Silicon are main classes of abrasive solids found in fuels. High levels of abrasive particles at the engine inlet may lead to abnormal wear and tear of the fuel system components, piston rings and cylinder liners. In fact, to control the amount of catalyst fines delivered to the engine, many engine builders specify a maximum limit of 15 mg/kg of Aluminium plus Silicon at the engine inlet.

An efficiently operating fuel purification system is the preliminary method of removing these particles. Measuring the fuel’s Aluminium and Silicon concentrations before and after the system’s centrifuge provides an indication of the efficiency of the purification system in removing catalyst fines.

OUR RECOMMENDATIONS

Maritec-Naias recommends collecting samples from within the fuel system at points such as the fuel oil tank transfer pump, before and after centrifuge, service tank and after filter samples to check the fuel cleaning efficiency.

Maritec-Naias states, while all presented findings are true, this document, does not reflect on the overall quality of fuel being supplied in the Singapore region. If you intend to bunker at this region please request a Certificate of Quality prior to loading.

Maritec-Naias can assist you with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to Contact us.

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Findings & Insights:

In the recent-past few months several ships in the Singapore and Rotterdam area reported operational problems including fuel sludging, injector failure, filter clogging, system deposits and corrosion of turbocharger nozzle rings.

In light of the reported problems, CTI-Maritec swiftly carried out extended Gas Chromatography Mass Spectrometry (GC-MS) testing for Very Low Sulphur Fuel Oil (VLSFO) samples from these said vessels.

GC-MS testing by Solid Phase Extraction (SPE) method showed the presence of high concentrations (>10000 PPM) of cardol, cardanol, anacardic acid and other alkyl resorcinols. All mentioned compounds, which are substituted long chain phenols, indicated the fuel was blended with Cashew Nutshell Liquid (CNSL) from undeclared source materials or production processes.

CNSL is a non-FAME BioFuel, which is a naturally occurring byproduct of the cashew nut industry and acts as a low-cost alternative renewable fuel. It’s a substituted phenol, which is highly reactive and less stable owing to its high iodine value. The application of CNSL is known in the production of plastic, resin, adhesives, laminates, and surface coatings. CNSL has high acid values and is therefore highly corrosive as well. High Potassium found in CNSL blend fuels cause serious post-combustion deposits and corrosion of turbocharger nozzle rings.

The latest version of ISO:8217 specifies the accepted BioFuels such as FAME based biofuels, Hydrotreated Vegetable Oil (HVO), defined by the specifications of EN 14214, ASTM D6751 and EN 15940 respectively. These fuels are now established and acknowledged by equipment manufacturers (OEM), Classification Societies (Class) and flag Administrations as ‘drop-in’ fuels. There is no specification available for CNSL from any authorised body like above.

CTI-Maritec Recommendations:

CTI-Maritec recommends that shipowners should not use 100% CNSL as a marine fuel or use CNSL as a blending component in marine fuel, which is contrary to the guidance by IMO on best practices for suppliers on the quality of fuel oil delivered to ships.

MEPC.1 /Circ. 875/Add.1 section ‘5’ – where it states that:

5.3 Blend components should be tried and tested so that their typical properties and suitability for bunker production and how they combine with other components is well understood…… and

5.4 Where there are any uncertainties as to the nature and quality of blend component, any issue should be identified and resolved before its use in the production of bunkers.

Furthermore, CTI-Maritec recommends not using unestablished bioproducts in marine diesel engines. Blending these substances in a marine fuel might meet specifications as per ISO:8217 tables 1 and 2 parameter limits but may not fulfil general requirements of compliance as per Clause 5 of ISO:8217.

CTI-Maritec can assist you with further information on the quality of bunkers tested in different regions. For further information or assistance please do not hesitate to Contact us.

FINDINGS & INSIGHTS

In the last few weeks CTI-Maritec has tested multiple fuel oil bunker samples from vessels that have taken fuel/bunkered in MALTA and reported operational issues and/or tested to have the presence of high levels of chemical compounds.

Extended Gas Chromatography Mass Spectrometry (GC-MS) testing by ASTM D7845 was conducted for two Very Low Sulphur Fuel Oil (VLSFO) samples, which showed the presence of high concentrations of acetophenone, phenolic compounds (4-cumylphenol, phenol and others), styrene glycol and phenethyl alcohols. Furthermore, testing by Solid Phase Extraction (SPE) GC-MS technique indicated low levels of bisphenol isomers, fatty acids, long chain fatty acids and dehydroabietic acid. All mentioned compounds are non-hydrocarbons. Our GC-MS analysis also indicated the presence of reactive hydrocarbons like DCPD, Dihydro-DCPD, Styrene and Indene.

The common problems encountered, as reported by the vessels, were sludging, filter clogging and in some instances, fuel pump issues associated with phenolic compounds and phenethyl alcohols.

Due to the high levels of these chemical compounds, the fuels do not meet the general requirement and is considered as off-spec fuel as per clause 5 of ISO8217 and MARPOL Annex VI regulation 18 which states:

“The fuels shall be homogeneous blends of hydrocarbons derived from petroleum refining. This shall not preclude the incorporation of small amounts of additives intended to improve some aspects of performance.”

The fuels shall be free from inorganic acids and from used lubricating oils. The fuel should not include any added substance or chemical waste which,

a) jeopardizes the safety of ships or adversely affects the performance of the machinery; or

b) is harmful to personnel; or

c) contributes overall to additional air pollution.”

CTI-Maritec Recommendations:

CTI-Maritec recommends to:

• Closely observe the vessel fuel system/s for signs of filter clogging and purifier sludging and additionally, increase vigilance on the centrifuges to monitor overloading.
• Increase frequency of their de-sludging cycle depending on the accumulated sludge.
• Possibly reduce the Mean Time between bowl cleaning of the purifier and fuel system filters.
• Avoid blending with other fuels, in particular marine diesel and gas oil and also other fuel oil as such mixing may well increase the sediment problem.

Furthermore, at these levels of concentration of chemical compounds present in fuel oil, there is an increased risk of excessive wear to the vessel’s fuel pump plunger and barrel assembly. Therefore, it is advised to monitor the fuel pump index closely to check for deteriorating performance. As a back-up, ensure there are sufficient spare seals and plunger barrel assembly to replace damaged units if necessary.

In addition, as a precaution, it is advised to closely monitor the performance of the engines while using this fuel to detect any deterioration of the fuel injection equipment performance and the sealing effect of the piston rings.

This document, however, does not reflect on the overall quality of fuel being supplied in Malta. If you intend to bunker in this region, please request for a Certificate of Quality prior to loading.

CTI-Maritec can assist you with further information on the quality of bunkers tested in different regions. For further information or assistance please do not hesitate to Contact us.

FINDINGS & INSIGHTS

From the period of 08 May 2024 to 05 July 2024, Maritec Pte Ltd (hereafter referred to as CTI-Maritec) tested twenty-two samples representing both HSFO and VLSFO deliveries from various suppliers in the Amsterdam-Rotterdam-Antwerp (ARA) region, which showed Aluminium and Silicon (Al+Si) concentrations ranging from 40 mg/Kg up to 177 mg/kg.

Out of the twenty-two samples, CTI-Maritec found Aluminium and Silicon (Al+Si) concentrations in two samples to be above 100 mg/Kg and in one sample at 68 mg/Kg level.

While the rest of the samples fell within the specifications of ISO8217:2005 (80 ppm) and even within the ISO8217:2010/2017 specification (including permitted limits of 72 PPM as per ISO4259 for a single test result), the Catfines content were still considered at high levels. Many of these samples were also found to have high density, high TSP and high CCAI.

Aluminium and Silicon are main classes of abrasive solids found in fuels. High levels of abrasive particles at the engine inlet may lead to abnormal wear and tear of the fuel system components, piston rings and cylinder liners. To control the maximum amount of catalyst fines delivered to the engine, many engine builders specify a maximum limit of 15 mg/kg of Aluminium plus Silicon at engine inlet.

An efficiently operating fuel purification system is the main way of removing these particles. Measuring the fuel’s Aluminium and Silicon concentrations before and after centrifuge provides an indication of the efficiency of the system in removing catalyst fines.

Due to relatively high TSP, fuels might generate increased sludge formation, especially at the Purifiers and filters. Due to high CCAI, fuels might have ignition and combustion related issues.

Our Recommendations:

CTI-Maritec recommends collecting samples from within the fuel system at points such as the fuel oil tank transfer pump, before and after centrifuge, service tank and after filter samples to check the fuel cleaning efficiency.

This document, however, does not reflect on the overall quality of fuel being supplied in ARA region, if you intend to bunker at this region please request for a Certificate of Quality prior to loading.

CTI-Maritec can assist you with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to Contact us.

FINDINGS & INSIGHTS

Maritec Pte Ltd has tested seven samples from four different suppliers representing HSD and Bio Distillate grade deliveries in Indonesia with flashpoint as low as 35°C for the period of 10 December 2023 to 19 December 2023.

SOLAS Chapter II-2, Part B, Reg. 4. Clause 2.1.1 states:

“The following limitations shall apply to the use of oil as fuel, except as otherwise permitted by this paragraph, no oil fuel with a flashpoint of less than 60°C shall be used.”

Recommendations by CTI-Maritec: 

If your vessel has bunkered a low flashpoint fuel it is prudent to observe the below precautions.

• Flame screens on tank vents should be maintained in good condition and there should be no sources of ignition in the vicinity of the vents. This will assist in safe natural ventilation of volatile components in the fuel.
• No Smoking, No naked flame and No hot work must be allowed at any areas near to tank air vents.
• Send additional tank(s) samples upon arrival in port to check the fuel properties and flash point results especially if there has been co-mingling of fuels in bunker tanks.
• If the vessel is out at sea it may be possible to obtain dispensation from your Flag State Administration up to next arrival port.
• Put the supplier on notice promptly and notify your P&I club.

ISO 4259 interpretation for tested flashpoint temperature is not taken into consideration here as the safety of onboard crew and vessel is of higher precedence.

This document however does not reflect on the overall quality of fuel being supplied at Indonesia, if you intend to bunker at this region please request for a Certificate of Quality prior to loading.

Maritec Pte Ltd can assist you in with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to contact us.

FINDINGS & INSIGHTS

Maritec Pte Ltd has tested three samples of VLSFO deliveries in Singapore with flashpoint as low as 54°C from different suppliers and barges as well as eleven samples (from the period of 5^th September 2023 to 19^th October 2023) of HSD and B35 deliveries in Indonesia with flashpoint as low as 41°C from mostly a single supplier.

SOLAS Chapter II-2, Part B, Reg. 4. Clause 2.1.1 states:

“The following limitations shall apply to the use of oil as fuel, except as otherwise permitted by this paragraph, no oil fuel with a flashpoint of less than 60°C shall be used.”

Recommendations by CTI-Maritec:

If your vessel has bunkered a low flashpoint fuel it is prudent to observe the below precautions.

• Flame screens on tank vents should be maintained in good condition and there should be no sources of ignition in the vicinity of the vents. This will assist in safe natural ventilation of volatile components in the fuel.
• No Smoking, No naked flame and No hot work must be allowed at any areas near to tank air vents.
• Send additional tank(s) samples upon arrival in port to check the fuel properties and flash point results especially if there has been co-mingling of fuels in bunker tanks
• If the vessel is out at sea it may be possible to obtain dispensation from your Flag State Administration up to next arrival port
• Put the supplier on notice promptly and notify your P&I club.

ISO 4259 interpretation for tested flashpoint temperature is not taken into consideration here as the safety of onboard crew and vessel is of higher precedence.

This document however does not reflect on the overall quality of fuel being supplied at Singapore, if you intend to bunker at this region please request for a Certificate of Quality prior to loading.

Maritec Pte Ltd can assist you in with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to contact us

DOWNLOAD THIS BUNKER FLASH

FINDINGS & INSIGHTS

In recent times, there have been notable machinery issues affecting vessels bunkering from the United States, particularly in the Houston area. These problems include failures in Main Engine startup, loss of power from auxiliary engines resulting in the loss of propulsion, and fuel pump malfunctions, among others. These concerns have been widely reported in the news.

CTI-Maritec, an independent fuel testing laboratory, has undertaken an investigation into fuel samples collected from this region. The analysis has revealed elevated levels of specific compounds, which have raised concerns about the stability of the fuel being used in these vessels.

Over the past few months, our testing has identified three vessel fuel samples with significantly high levels of two compounds:

• Dihydro-dicyclopentadiene (ranging from 1200 ppm to 6000 ppm) and
• Tetrahydro-dicyclopentadiene (ranging from 2500 ppm to 5500 ppm).

These samples exhibited a poor reserve stability, measured using manual P-value by SMS1600 test method. This suggests a lack of homogeneity in the fuel sample, which could potentially pinpoint to similar conditions in the supplied fuel.

Table 1 shows our finding for one of the samples upon progressive dilution with cetane, a paraffinic solvent prescribed for SMS1600 test method.

Table 1: Progressive cetane dilution and microscopic observation

For acceptable fuel stability asphaltene flocculation generally does not occur upon cetane dilution up to 30%, and fuels that are able to withstand dilution up to 50% are considered as stable fuels for strategic long-term storage.

For the sample tested, asphaltene flocculation was detected prior to cetane dilution and gradual increase of cetane % increased the observed flocculation levels which indicates the fuel has poor stability reserve.

The presence of the compounds detected at elevated levels for the fuels tested increases the risk of unmanageable sludge deposition in the fuel oil system. This, in turn, can result in complications related to fuel treatment processes and engine operation.

It is worth noting that while these compounds are commonly found in marine bunker fuels, their current prevalence in this region is unusually high. This may indicate inadequate quality control measures within the production and supply chain.

Based on the above findings, it can be argued that these fuels represented by the tested samples may not meet the general requirements outlined in clause 5 of ISO8217. Therefore, if your vessel is bunkering in this area, we strongly advise you to request the fuel supplier to provide a Certificate of Quality from an accredited laboratory. This certificate should, at a minimum, confirm the absence of the aforementioned compounds using accredited GC-MS methods. This precautionary measure is crucial to ensure the safe and reliable operation of your vessel’s machinery.

This document however does not reflect on the overall quality of fuel being supplied in the Houston region.

Maritec Pte Ltd can assist you in with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to contact us

DOWNLOAD BF202310-01

FINDINGS & INSIGHTS

Since the last alert (BF202207-01) dated on 05-July-2022 on Chemical Contaminants in Fuels from ARA Region (Amsterdam, Rotterdam & Antwerp), CTI-Maritec has kept a close watch on the fuel quality in the region. More recently, several VLSFOs delivered in this region are still observed with the presence of chemical contaminants. These VLSFOs also indicated elevated potassium content and acid number.

Forensic analysis by Gas Chromatography and Mass Spectrometry techniques, specifically ASTM D7845 GC/MS and Solid Phase Extraction (SPE) GC/MS, on some of the samples revealed the presence of the following compound groups at abnormally high concentrations

• Fatty Acids and Monoglycerides (>1000ppm)
• Alkylresorcinols (>2000ppm)
• Phenolic compounds (>1000ppm)

It is difficult to determine a safe concentration level suitable for marine diesel engine usage or the baseline wherein machinery problems may occur.  Due to the severity of the Machinery problems faced, we urge vessel operators to continue pre-emptively testing the fuels bunkered in the region by accredited test methods to detect these contaminants assessing the risk each bunker stem has on the vessel machinery.

Recommendation by CTI-Maritec:

1. Obtain quality assurance and test proof from suppliers on the absence of contaminants in the intended stem prior bunker delivery (This will require testing beyond the scope of standard ASTM D7845-20 test method)
2. Plan your bunkers well in advance to keep the incoming fuel segregated and reduce the risk of comingling.
3. Ensure sampling procedure during bunkering is witnessed by both supplier and receiver and sample bottles are counter-sealed and same recorded in the Bunker Delivery Note.
4. Be aware of your bunker supply contract and the notification time limit stipulated to flag potentially problematic fuels to the supplier.
5. Look for signs of abnormally high potassium content (>110ppm) and/or high total acid number (>1.5mgkoh/g) and pre-emptively analyze the bunker fuel by Gas Chromatography and Mass Spectrometry (GC-MS) that can reveal the presence of undesirable compounds in the fuel thus safeguarding vessel operations.
6. Where chemical compounds have been detected, gather sufficient evidence to support further investigation. Proceed to conduct joint analysis in agreement with the supplier by an independent laboratory capable of detecting the compounds to determine the compliance with ISO8217 clause 5 – General Requirements.

This document however does not reflect on the overall quality of fuel being supplied at ARA region.

Maritec Pte Ltd can assist you in with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to contact us

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FINDINGS & INSIGHTS

Recently MARITEC has investigated 5 VLSFO samples that were bunkered in the US-Gulf region between June to July 2022. Operational Feedback was received from 2 vessels that had used these fuels indicating issues such as excessive wear of fuel pump plungers, barrels, and fuel injectors.

Further investigation through forensic analysis by ASTM D7845 Direct Injection and Solid Phase Extraction GCMS methods, has indicated these fuels to have an uncharacteristic detection of chemical species, specifically:

• Tetrachloroethylene (Chlorinated Organic Compound) at concentration less than 100ppm
• FAME at concentrations 300 to 400ppm
• Fatty Acids at concentrations between 50-2000ppm

Though there is insufficient literature that the presence of these compounds especially at these concentration levels causing issues as mentioned above, it remains a cause of concern as they are not natural products of a refinery stream.

Through experience and feedback from vessel usage, these compounds primarily affect the fuel service system resulting in excessive wear of injection components.

It may not always be possible to get a thorough GCMS analysis along with the supplier’s Certificate of Quality prior bunkering. If you are planning to bunker in this region, we recommend ensuring correct sampling procedure and proper documentation is carried out onboard to ensure true representation of the bunkered fuel. Record any event and document evidence indicating any operational issues faced onboard by the vessel during the fuel usage.

Alternatively, CTI-Maritec advises to pre-emptively conduct GCMS by D7845 and Solid Phase Extract to look out for such deleterious material and check whether the fuel supplied to the vessel contravenes stipulations of the MARPOL Annex VI Regulation 18.3 & ISO 8217 Clause 5 both of which mentions that marine fuels supplied to the ships should be free from chemical waste or added substances at quantities that may jeopardize the safety or adversely affects the performance of the machinery.

This document however does not reflect on the overall quality of fuel being supplied at US Gulf region, it is however advised to take the necessary precautions as indicated above.

Maritec Pte Ltd can assist you in with further information on quality of bunkers tested in different regions. If you require any other information or assistance do not hesitate to contact us.

DOWNLOAD BF202207-04

FINDINGS & INSIGHTS

Maritec has tested several VLSFOs delivered in the ARA region to be observed with the presence of chemical contaminants in the recent months. These VLSFOs also indicated elevated potassium content and acid number.

From these samples, CTI-Maritec has obtained feedback from vessels encountering rapid and excessive wear on fuel pumps on main propulsion engines and a tendency for increased deposit formation in the exhaust system.

Figure 1: Exhaust grid fouling
Figure 2: Turbocharger Nozzle Ring fouling
Figure 3: Fuel Pump Plunger wear down

Forensic analysis by Gas Chromatography and Mass Spectrometry techniques, specifically ASTM D7845 GC/MS and Solid Phase Extraction (SPE) GC/MS, on some of the samples revealed the presence of the following compound groups at abnormally high concentrations

• Fatty Acids and Monoglycerides (>1000ppm)
• Alkylresorcinols (>2000ppm)
• Phenolic compounds (>1000ppm)

Fatty acids and Monoglycerides are acidic compounds commonly found in fuels where the FAME content has broken down in the presence of water and have known to cause costly accelerated wear in fuel oil injection pumps. The presence of these compounds can also suggest an inclusion of substandard Bio-fuels into the blend. This also explains the high potassium content in the fuel as Potassium Hydroxide (KOH) is one of the possible catalysts used in the production of bio-diesel. The separation of the spent catalyst out from the final product is a complicated and expensive process. The increased potassium can also contribute towards the total ash forming tendency of the fuel leading to abnormal deposit formation in post combustion exhaust system components.

The presence of Alkylresorcinols and phenolic compounds suggests the inclusion of shale oil which is allowed as per the definition of ‘petroleum fuel’ in ISO 8217 standards. CTI-Maritec’s experience however has shown that the presence of these compounds tends to cause fuel instability leading to issues like filter blockages and purifier bowl overloading. This is despite the Total Sediment potential tests being within specification. Any sludge not capable of being removed by the fuel treatment system can cause combustion issues in the main engine.

If your vessel is expected to bunker in the ARA region; CTI Maritec advises to check the pre-bunkering certificate of quality or Manifold sample test results for signs of abnormally high potassium content (>110ppm) and/or high total acid number (>1.5mgkoh/g) and pre-emptively analyze the bunker fuels by Gas Chromatography and Mass Spectrometry (GC-MS) that can reveal the presence of undesirable compounds in the fuel thus safeguarding vessel operations.

In every case, CTI Maritec urges bunker fuel receivers to ensure thorough attention is given to the witnessing of correct sampling procedures during bunkering, counter-sealing and recording of seals in the bunker delivery note and any other documentation required to ensure correct representative samples are obtained during the bunkering process.

Collecting objective evidence on the storage, treatment and usage of the fuel is to be always given a high priority in the event an operational problem occurs to determine if the fuel used was one of the root causes for a machinery failure.
This document however does not reflect on the overall quality of fuel being supplied at ARA region.

Maritec Pte Ltd can assist you in with further information on quality of bunkers tested in different regions. If you require any other information or assistance, please do not hesitate to contact us

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