MALAYSIA

During the last three months, we have received three VLSFO fuel samples from Malaysia ports with density above 991 kg/m³, and acid number above 1.5 mg KOH/g fuel, with one sample tested for estimated cetane number yielding a value of 8.7. Based on our database, the average ECN values for HSFOs were 18.6 and for VLSFOs was 35.7; therefore, an ECN value of 8.7 is considered as a fuel with poor ignition quality.

GCMS analysis indicated the presence of phenolic compounds exceeding 15,000 ppm, non-phenolic oxygenated compounds above 1,000 ppm, and approximately 1,000 ppm of reactive components. Of these three cases, one vessel reported operational problems and stated that the fuel could not be used without additional blending, another vessel consumed the fuel without reported issues, while no operational feedback has yet been received for the third case. Taken together, the presence of high phenolic content, oxygenated compounds, reactive species, elevated acid number, and poor ignition properties may be indicative of shale oil or shale oil-derived components in the blend.

SHALE OIL

Shale oil is characterized by relatively high density, elevated aromatic and phenolic content, high concentrations of oxygenated compounds, poor ignition quality, thermal instability, and a tendency to form carbon deposits. When blended into bunker fuels or bunker fuel blending components, these characteristics may increase the overall fuel density and aromaticity, potentially leading to longer ignition delay, reduced combustion efficiency, sludge formation, injector fouling, and fuel instability, particularly if the fuel has not been adequately stabilized or hydrotreated. The presence of shale oil in bunker fuel can increase the Total Acid Number (TAN), consistent with the high acid number values observed in these samples.

However, because bunker fuels are already heavy residual fuels with less stringent requirements, limited incorporation of shale oil may still be technically acceptable for marine engines, which is one reason such fuels may remain within the ISO 8217 specification limits. Proper fuel management remains critical, including viscosity control, compatibility assessment, and correct fuel heating and treatment procedures onboard.

SINGAPORE REVIEW

We have reviewed fuel samples from the Port of Singapore over the last 3 months to assess whether any may contain shale oil blend components based on GCMS test results. Several samples collected showed similar contaminant fingerprints, including the presence of phenolic compounds, reactive species, oxygenated compounds, and free fatty acids. The acid number of these samples was also higher than 1.5 mg KOH/g fuel. The detection of phenolic compounds, including resorcinol-type compounds, may indicate the presence of shale oil-derived components in the blend.

Among these samples, there was one reported case with operational issues, including fuel pump seizure and sludging. The affected fuel contained approximately 7,000 ppm phenolic compounds, 670 ppm reactive species, 855 ppm oxygenated compounds, and 400 ppm free fatty acids. However, no operational problems have been reported to date from other vessels using fuels with a similar contaminant profile.

We are continuing to investigate these cases to better understand whether the observed operational issues are related to fuel composition, and we will provide further updates as additional information becomes available.

RECOMMENDATIONS

Based on the current observations, we recommend performing GC-MS analysis for fuels with an acid number greater than 1.5 mg KOH/g fuel.

PRECAUTIONS AND SUGGESTED MITIGATION OPTIONS

One possible mitigation measure is blending the affected fuel with a compatible, clean fuel that does not contain chemical contaminants, provided that appropriate compatibility testing is performed beforehand.

In cases where sludge formation occurs, asphaltene dispersant additives may help stabilize the fuel and reduce sludge generation. However, it should be noted that there are currently limited studies evaluating the effectiveness of such additives specifically in fuels affected by shale-oil-related contamination.

The following precautionary measures are recommended in cases of contaminated fuels:

  1. Ensure all maintenance records are fully updated and shared with relevant stakeholders, including insurers and vessel owners. This will assist in identifying and documenting any fuel-related operational issues should problems arise.
  2. Carry out a detailed inspection of the fuel supply and circulation system before use. This should include verification of the fuel transfer system, fuel treatment equipment, injection system, engine condition, and overall engine performance to confirm that all systems are operating correctly.
  3. The operational impact of contaminated fuel may vary depending on several factors, including contaminant concentration, engine age and condition, operating temperature, maintenance standards, and onboard fuel management practices. As a precaution, engine performance and operating parameters should be closely monitored by the vessel crew throughout fuel consumption.

This document (insight) does not reflect the overall quality of fuel being supplied from Malaysia & Singapore ports.

Please do not hesitate to contact us if you require any further information or assistance.