Over the past month, Viswa has received seven VLSFO samples supplied from a single supplier in China, where vessels reported frequent filter clogging, particularly of the 10-micron filters. The reported filter replacement interval was approximately 1–2 hours following the commencement of fuel consumption.
Selected problem fuels were subjected to comprehensive GC-MS analysis, and EN 14077 testing. EN 14077 analysis indicated total organic chloride concentrations ranging from 60 to 167 ppm in tested samples.
According to ISO 8217:2024, fuel is considered free of organic chlorides when the total organic chlorine content does not exceed 50 mg/kg as determined by EN 14077. At elevated temperatures, organic chlorides may decompose to form hydrogen chloride gas, which can subsequently form hydrochloric acid in the presence of water. Based on our experience to date, no short term operational issues have been reported to us in connection with fuels containing organic chloride levels within this range. However, the long-term effects of continuous operation on such fuels have not been evaluated by Viswa.
Comprehensive GC-MS analysis identified the presence of higher concentrations of 1,2-dichloropropane and 2-chloro-1-propanol in all tested fuels.
All problem fuels exhibited a similar contaminant fingerprint, including caprolactam concentrations ranging from 295–1021 ppm.
Caprolactam (C₆H₁₁NO) is a cyclic amide primarily used as the monomer for the production of nylon-6. Based on our database, the presence of caprolactam in VLSFO is uncommon and has not been frequently observed in the samples analysed to date.
We are continuing to investigate the presence of other potential polymeric materials in these samples. At present, there is no standardized method for the detection and quantification of polypropylene or polyethylene in fuel samples.
Further updates will be provided as additional information becomes available from these investigations.
This document does not reflect the overall quality of fuel being supplied in China port. Please do not hesitate to contact us if you require any further information or assistance.