Recently MARITEC has investigated 5 VLSFO samples that were bunkered in the US-Gulf region between June to July 2022, as well as several VLSFOs delivered in the ARA Region, finding contamination issues.
US-Gulf region
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
These compounds primarily affect the fuel service system resulting in excessive wear of injection components. However, MARITEC warns that it may not always be possible to get a thorough GCMS analysis along with the supplier’s Certificate of Quality prior bunkering.
ARA Region
Since the last alert from July 5 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
Taking the above into consideration, MARITEC recommends the following:
- 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).
- Plan your bunkers well in advance to keep the incoming fuel segregated and reduce the risk of comingling.
- 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.
- Be aware of your bunker supply contract and the notification time limit stipulated to flag potentially problematic fuels to the supplier.
- 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.
- 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.
