The shipping industry is under growing pressure to comply with decarbonisation regulations, particularly in the EU/EEA regions, where authorities are now focusing on reducing greenhouse gas (GHG) emissions from ships operating in these waters. These regulations emphasize not only the emissions of the ships themselves but also the carbon intensity of the fuels they burn. As the 2023 IMO Strategy on Reduction of GHG Emissions from Ships is adopted, this focus will extend to a broader geographical area, intensifying the need for cleaner fuels.
To meet these regulations, the shipping industry is shifting toward low- to zero-carbon emission fuels, including biofuels. One such option being explored is Cashew Nutshell Liquid (CNSL), which is a renewable byproduct of the cashew nut. CNSL offers a low-cost alternative fuel option; however, its characteristics present challenges. It has high acidity, making it highly corrosive, and it exhibits poor combustion properties. Nevertheless, it can improve the lubricity and energy content of fuel blends. CNSL contains phenolic compounds, including cardol, cardanol, and anacardic acid, which have the potential for polymerisation, resulting in instability.
Recently, Skuld, an insurance provider for the maritime industry, has observed several vessels encountering operational problems related to their fuel systems. These issues, such as injector failure, clogging of filters and heaters, fuel sludging, and deposit buildup, were traced back to contamination by phenolic compounds in the fuel. Extended Gas Chromatography Mass Spectrometry (GCMS) testing of Heavy Fuel Oil (HFO) and Very Low Sulfur Fuel Oil (VLSFO) samples from the affected vessels revealed a high concentration of these problematic compounds.
Blending CNSL with traditional fuels can lead to severe engine component damage, including accelerated wear of fuel pumps, cracks in fuel systems, and poor engine performance, which can result in a loss of power.
Given these risks, Skuld advises its members to exercise caution when procuring bunker fuels. The following guidelines are recommended:
- Due Diligence in Supplier Selection: Always conduct thorough vetting procedures when selecting a bunker supplier.
- Testing and Fuel Specifications: Use the latest version of ISO 8217:2024 for fuel testing, especially for bio-residual marine fuels. Ensure that sales terms and warranties related to the fuel’s fitness are reviewed.
- Certificate of Quality: Request a Certificate of Quality prior to bunkering to ensure the fuel meets necessary standards.
- Fuel Analysis: Carry out a comprehensive fuel analysis before use. As phenolic compounds are not detectable in the standard ISO 8217 test, Skuld recommends an extended GCMS test from a reputable fuel laboratory.
- Avoid Unestablished Biofuels: Do not use untested or unverified biofuel products in marine diesel engines.
Skuld’s Loss Prevention department is available to provide further clarification or assistance on these matters.
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