Answer
Before using biofuel onboard, as Chief Engineer I would check both fuel quality and machinery compatibility.
Main checks:
- Confirm the engine maker has approved the biofuel/blend for the main engine, generators, boilers and fuel system.
- Check the fuel against ISO 8217:2024 and identify the grade, especially whether it contains FAME and at what percentage. ISO 8217:2024 now includes specific grades permitting FAME up to B100.
- Review the fuel analysis report: viscosity, density, flash point, sulphur, acid number, oxidation stability, water, sediment, cold-flow properties and contaminants.
- Check compatibility with existing fuel before mixing. Different stable fuels can become unstable when mixed, causing sludge and filter blockage.
- Prefer segregated storage initially and avoid unnecessary mixing.
- Check tank cleanliness because biofuel/FAME can have a cleaning effect, loosening old deposits and causing filter clogging.
- Check material compatibility of seals, hoses, gaskets and elastomers.
- Check the fuel’s storage stability. FAME is more susceptible to oxidation and water absorption, so prolonged storage should be avoided.
- Check for microbial growth risk, especially where water contamination is possible.
- Prepare extra filters and monitor purifier/filter differential pressure closely after changeover.
- Adjust fuel temperature/viscosity control, injection settings and cylinder lubrication according to engine-maker guidance.
- Conduct a proper risk assessment and fuel changeover plan, brief engineers, and initially monitor exhaust temperatures, combustion, fuel pressure, filters and engine performance closely.