Fuel Oil References

Standards and Classification

In the maritime sector, fuel oils are pivotal for the operation of ships, with their classification reflecting their physical characteristics and suitability for different types of engines and environmental regulations. Unlike the classification used in automotive or stationary engines, marine fuels are categorized based on their distillation process, viscosity, and sulphur content, adhering to international standards such as ISO 8217. Here’s a closer look at the various types of marine fuel oils:

MGO (Marine Gas Oil): This is akin to No. 2 fuel oil and is produced purely from the distillation process. MGO is known for its cleanliness and high quality, making it suitable for ships navigating in environmentally sensitive areas.
MDO (Marine Diesel Oil): A blend that includes heavy gasoil and may contain minor amounts of black refinery feedstocks. Its viscosity does not exceed 12 cSt, eliminating the need for heating before use in internal combustion engines.
IFO (Intermediate Fuel Oil): This type represents a mix of gasoil and heavy fuel oil, containing less gasoil compared to MDO, making it heavier and requiring pre-heating.
HFO (Heavy Fuel Oil): Almost entirely consisting of residual oil, HFO is the heaviest type of marine fuel, equivalent to No. 6 fuel oil in terms of its composition.
MFO (Marine Fuel Oil): Essentially another term for HFO, indicating its heavy, residual nature.

Despite the variety, marine diesel oil often includes some amount of heavy fuel oil, distinguishing it from regular diesel fuels used in land vehicles.

Ignition Quality Indices

CCAI (Calculated Carbon Aromaticity Index) and CII (Cetane Index) are two critical measures of the ignition quality of residual fuel oils. While CCAI is frequently calculated for marine fuels, these oils are primarily traded based on their maximum viscosity as per ISO 8217. This is due to marine engines’ capability to operate on fuels of varying viscosities. Viscosity is measured in centistokes (cSt), and the pricing of marine fuels often correlates with their viscosity and Sulphur content.¹

Common Marine Fuels Based on Viscosity and Sulphur Content

IFO 380 – Intermediate fuel oil with a viscosity of up to 380 cSt and sulphur content below 3.5%.
IFO 180 – Similar to IFO 380 but with a maximum viscosity of 180 cSt.
LS 380 – Low-sulphur variant with a viscosity up to 380 cSt and sulphur content below 1%.
LS 180 – Low-sulphur variant with a viscosity up to 180 cSt and sulphur content below 1%.
MDO – Marine diesel oil.
MGO – Marine gas oil.
LSMGO – Low-sulphur marine gas oil, with sulphur content below 0.1%, mandated for use in EU ports and anchorages as per EU Sulphur Directive 2005/33/EC.
ULSMGO – Ultra-low-sulphur marine gas oil, with even lower sulphur levels, suitable for use in US territories and the EU for inland applications.

Fuel Oil Density and Purification

The density of marine fuel oil is a crucial factor, particularly in the purification process before its use. Fuel oils must have a density sufficiently different from water to enable their purification using centrifugal force.² This process is essential for removing water and impurities, ensuring the fuel’s efficiency and reducing engine wear and tear. While older purifiers are suited for fuels with a maximum density of 991 kg/m^3, modern systems can handle fuels up to 1010 kg/m^3.

Importance in Maritime Industry

Understanding the specifications, classifications, and standards of marine fuel oils is indispensable in the maritime industry. It ensures compliance with environmental regulations, optimizes engine performance, and enhances fuel efficiency. As regulations evolve and the industry moves towards more sustainable practices, the role of cleaner, alternative fuels is set to increase, marking a significant shift in fuel oil usage and standards.

Emerging Trends in Marine Fuel: LNG and HVO

The maritime industry is increasingly moving towards greener alternatives to traditional marine fuels, driven by stringent environmental regulations and a global push for sustainability. Among these alternatives, LNG (Liquefied Natural Gas) bunkering and HVO (Hydrotreated Vegetable Oil) fuel are gaining prominence for their environmental benefits and potential to reduce the shipping industry’s carbon footprint.

LNG Bunkering: A Path to Cleaner Shipping

LNG bunkering is the process of providing liquefied natural gas to a ship for use as fuel. This technology has emerged as a key player in the maritime industry’s efforts to reduce emissions, thanks to LNG’s cleaner-burning properties. Compared to traditional marine fuels, LNG significantly reduces emissions of sulfur oxides (SOx), nitrogen oxides (NOx), carbon dioxide (CO2), and particulate matter.

Advantages of LNG:

Reduced Emissions: LNG emits up to 25% less CO2 than conventional marine fuels, virtually eliminates SOx emissions, and significantly lowers NOx emissions and particulate matter.³
Global Compliance: Using LNG helps ships meet the International Maritime Organization (IMO) regulations, including the IMO 2020 global Sulphur cap and the forthcoming IMO greenhouse gas (GHG) reduction targets.⁴
Growing Infrastructure: The global network of LNG bunkering facilities is expanding, making it increasingly feasible for ships to refuel LNG across major ports worldwide.⁵

HVO Fuel: Sustainable Biofuel for the Seas

HVO fuel, or Hydrotreated Vegetable Oil, is a renewable diesel produced from vegetable oils or animal fats using a hydrotreating process. It stands out as a sustainable alternative to fossil diesel and marine fuels, capable of significantly reducing greenhouse gas emissions without the need for modifications to existing diesel engines.

Benefits of HVO Fuel:

Greenhouse Gas Reduction: HVO can reduce GHG emissions by up to 90% over its lifecycle compared to conventional marine fuels.⁶
Compatibility and Flexibility: HVO fuel can be used in pure form or blended with traditional fuels, offering flexibility for ships transitioning towards greener alternatives.
Reduced Emissions of Pollutants: Similar to LNG, HVO significantly lowers emissions of SOx, NOx, CO2, and particulate matter, contributing to cleaner air and compliance with environmental regulations.⁷

The Future of Marine Fuel

As the maritime industry seeks to navigate the challenges of environmental sustainability and regulatory compliance, LNG bunkering and HVO fuel represent vital steps forward. These alternatives not only pave the way for a greener shipping sector but also demonstrate the industry’s capacity for innovation and adaptation. With continued investment in fuel technology and infrastructure, the adoption of cleaner, renewable marine fuels is set to accelerate, marking a transformative era in maritime history.