Between May 20 and June 2, five samples of very low sulphur fuel oil (VLSFO) from two suppliers at the Port of Singapore displayed Aluminium and Silicon (Al+Si) concentrations ranging from 61 mg/kg to 68 mg/kg. During the same period, 15 VLSFO samples also registered elevated Acid Numbers, between 2.0 mg KOH/g and 2.5 mg KOH/g. These cat fine values surpass the ISO 8217:2010/2017 specification limit of 60 parts per million (ppm), although they remain within the permitted tolerance limit of 72 ppm under ISO 4259.
For freight forwarders and vessel operators, these findings signal potential risks associated with VLSFO bunkered in Singapore. High cat fines can cause abrasive wear to engine components, particularly fuel pumps and cylinder liners, leading to increased maintenance costs and potential operational downtime. Elevated acid numbers can accelerate corrosion within the fuel system. While the cat fines are within the ISO 4259 tolerance, consistent levels at the upper end of the specification still warrant caution. Forwarders should advise their shipping partners to exercise diligence in fuel management, including thorough on-board testing and potentially more frequent engine inspections, when bunkering in this region to mitigate risks to vessel schedules and cargo delivery.