Safe Bunkering of Biofuels. Bunkering of Biofuels in Maritime: Characteristics, Regulatory Landscape, and Safety Assessment

February 09, 2024

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(European Maritime Safety Agency) The ongoing Study on the Safe Bunkering with Biofuels (bio-methanol, FT-diesel, DME, HVO and FAME) has, in its first report, provided a comprehensive analysis of a pre-selection of biofuels in terms of its properties (flashpoint, toxicity, cold flow properties and others) and how those can raise safety concerns during bunkering operations in a preliminary hazard identification. The following reports will elaborate on the conclusions of the HAZID workshops to draw up a guidance and safety checklists for the bunkering of these fuels, including comparison with conventional fuels. READ MORE

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EUROPE: EMSA PUBLISHES BIOFUEL BUNKERING SAFETY STUDY (Bunkerspot)
EMSA: Ensuring safe bunkering practices for biofuels in maritime operations (Safety4Sea)

Excerpt from Safety4Sea: Summary of critical conditions

#1 Bio-methanol

Temperature

Methanol has a lower flashpoint (9.7 °C) compared to traditional marine fuels (≥ 60 °C), requiring careful additional safeguards to mitigate the risk of fire and explosion hazards.
Methanol’s normal boiling point is about 65 °C. This temperature is considered out of range for normal bunkering operations.

Material compatibility

Methanol can be corrosive to some materials (e.g., aluminium, copper, titanium, and polyvinyl chloride). Corrosion is prevented through the selection of materials in contact with methanol, or application of appropriate coating.

Miscibility and contaminants

Methanol has a high solubility in water. Even solutions of methanol containing up to 74% water may be flammable.

Toxicity

The Immediately Dangerous to Life or Health concentration (IDLH) of methanol is 6000 ppm. Primary risks related to methanol toxicity is through ingestion of the substance in its liquid state, but vapour inhalation and contact/absorption through the skin can also have harmful impact.

#2 Bio-FT-diesel

Temperature

Bio-FT-diesel may have a lower flashpoint than 60°C. As such, the IMO IGF Code could be mandatory, depending on the specified flashpoint of the bio-FT-diesel product.

#3 Bio-DME

Temperature

DME is a flammable gas under normal ambient conditions necessitating additional safeguards to avoid the risk of fire or explosion. The presence of surfaces above the autoignition temperature of DME (350 °C) is not considered credible during bunkering operations. However, sources of ignition still pose a risk.
DME will liquefy if cooled (below boiling point at -24.8 °C at 1atm) or pressurized (above the vapour pressure at 5.3 bar at 20 °C).
The freezing point of DME (-141.5 °C) is considered out of range during bunkering operations.

Pressure

If pressure drops below 5.3 bar at 20 °C, DME vaporizes, and due to the relative vapour density of DME (1.59) compared to air (1.0), becoming heavier than air and posing a risk of distant ignition or inhalation in confined spaces as it travels along the ground or water surface.

#4 HVO

Temperature

HVO share the same flashpoint specification as distillate marine fuels (≥ 60 °C), requiring similar flammability precautions.
Some HVO fuels, without additional cold flow processing, may exhibit poorer cold flow properties than MGO.

#5 FAME

Temperature

Cold temperatures can cause fuel degradation, clogging and reduced flow capabilities. Cold flow properties differ among biodiesels, with the cloud point for B100, for instance, ranging from -5 to 20°C. Typically lower tolerance to cold temperatures than MGO.
B100 flashpoint (≥ 101 °C) exceeds that of MGO (≥ 60 °C), signifying lower flammability. This temperature is not considered a credible risk during bunkering.

Contamination

FAME is more contamination-sensitive than MGO. Prevent water, oxygen, dirt, and rust introduction to maintain fuel quality. Exposure to water can facilitate for microbial growth and/or hydrolysis which may cause corrosion and formation of sediments.

Material compatibility

B100-compatible materials: carbon steel, aluminium, stainless steel, Teflon, Viton, Nylon, fluorocarbon, carbon filled acetal, fibreglass.
Not recommended materials (B100): copper, bronze, brass, zinc, lead, tin, galvanized metal, nitrile rubber, butadiene, Hypalon, natural rubber, neoprene, Polypropylene, Polyurethane, Polyethylene.

Overview of Regulations & Best Practices – Safe Bunkering

The chosen biofuels vary when it comes to regulatory coverage and industry best practices in terms of their safe bunkering. Bio-methanol is the most mature, whereas HVO and FAME, exhibiting similarities in regulatory coverage, share commonalities with conventional marine diesels, potentially allowing for the leveraging of existing frameworks. Bio-DME, being gaseous and not commercially available, represents a somewhat unique position in this context and has little coverage. Among the selected biofuels, bio-FT-diesel has the least coverage.

For the safe bunkering of some of the biofuels, especially HVO, FAME, bio-DME and to some extent FT-diesel, an specific design approach as that taken by the Port of Singapore may be a valid method for ensuring safety. While bio-methanol can rely more on earlier industry experience and the specific guidelines that comes with that. A riskbased approach for their safe bunkering therefore seems the most appropriate until their use matures.

Regulations concerning the blending of these fuels have been considered and the safe bunkering of these blends should follow those guidelines. Other industries do not seem to take the same approach as the maritime sector, preferring a pure “drop-in” approach with a minimal impact to existing infrastructure and procedures for fuelling. Requiring a strict approval process for the fuel to ensure minimal operational impact to existing technologies. It should be noted that strict rules and guidelines may hinder biofuel adoption, while having a minimal positive impact on safety. Keeping the comparable risk in mind between a biofuel and a conventional fuel through a risk assessment seems an appropriate method for ensuring their safe bunkering, while promoting adoption. The following overview covers each biofuel specifically. READ MORE