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MB Energy

Heavy Fuel Oil (HFO)

Short explanation: Heavy Fuel Oil (HFO), also referred to as bunker fuel or residual fuel oil, is a high-viscosity, dense fuel used in marine, industrial, and power generation applications. It delivers high energy output and is suited for continuous, heavy-duty operations.

With MB Energy, HFO supply is structured around your operational needs. We support consistent delivery, aligned with your infrastructure and consumption patterns, ensuring reliable fuel availability for critical processes.

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HFO

Energy to move

What is Heavy Fuel Oil (HFO)?

Heavy Fuel Oil (HFO) is a residual fuel derived from crude oil refining. It is characterised by its high density and viscosity, making it significantly thicker than distillate fuels such as diesel or Marine Gasoil (MGO).

HFO is primarily used in large-scale applications where high energy demand and cost efficiency are key factors. Its composition includes heavy molecules such as long-chain hydrocarbons and aromatics with extended side chains, contributing to its energy content and physical properties.

Under the 1973 MARPOL Marine Convention, HFO is defined as fuel with a density greater than 900 kg/m³ at 15°C or a kinematic viscosity exceeding 180 mm²/s at 50°C. It is typically black in appearance and requires specific handling due to its physical characteristics.

HFO is distinct from Marine Gasoil (MGO), which is a lighter, more refined fuel with properties closer to diesel. The two fuels differ significantly in composition, handling requirements, and application.

Typical Applications

Heavy Fuel Oil is used across sectors requiring high energy output and continuous operation.

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Marine propulsion

HFO is the predominant fuel for medium and low-speed marine diesel engines. Most large vessels are designed to operate on this fuel due to its energy density and cost profile.

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Power generation

Oil-fired power plants use HFO to generate electricity, particularly where large-scale, stable energy output is required.

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Industrial operations

Manufacturing facilities use HFO in boilers and thermal systems where high heat demand and continuous fuel supply are essential.

Technical Specifications

HFO is defined by measurable physical and chemical characteristics that influence handling, storage, and combustion performance.

Standards and Classification

According to the MARPOL Convention (1973), HFO is classified by:
- Density > 900 kg/m³ at 15°C  
- Kinematic viscosity > 180 mm²/s at 50°C 

These parameters define its classification as a residual, high-viscosity fuel.

Physical Properties

HFO is black in colour and highly viscous. Its density and flow behaviour require heating during storage and transport to maintain pumpability.

Chemical Composition

HFO contains a high proportion of heavy hydrocarbons, including long-chain molecules and aromatic compounds with extended side chains. This composition contributes to its high energy content.

Fuel Differentiation

HFO differs from Marine Gasoil (MGO), which is lighter and more refined. MGO behaves similarly to diesel, while HFO requires dedicated handling systems due to its viscosity and density.

Cold Flow Properties

IHO is supplied as a **winter-grade fuel year-round**, reducing the risk of waxing and maintaining flow performance in lower temperatures.

Product Benefits

Cost-effective supply

HFO provides a cost-effective fuel option for large-scale energy demand. Its availability and established supply chains make it suitable for industries requiring consistent fuel access.

High energy output

Its high energy content supports continuous operation in heavy-duty environments, including marine engines and industrial boilers.

Stable bulk storage

HFO offers stable storage characteristics when managed correctly, making it suitable for bulk storage in large tank systems.
ed for frequent deliveries.

Supply & Delivery

HFO supply requires specialised logistics due to its viscosity and density.

Storage is typically managed in large tanks equipped to handle heated fuel. Maintaining temperature is essential to ensure flow and usability.

Transport is carried out using heated tankers or pipelines designed for high-viscosity fuels. This ensures safe and controlled delivery from terminal to end-use location.

MB Energy supports supply planning aligned with your operational requirements, including coordination of delivery volumes and infrastructure compatibility.

Product Variants

HFO is not a single uniform product. Variants exist based on viscosity, density, and specific application requirements.

These differences influence handling, storage, and engine compatibility. Selecting the appropriate variant depends on your equipment configuration and operational profile.

Residual Fuel Oil Grades

Standard HFO grades vary in viscosity and density.
These are selected based on engine requirements, storage capability, and heating systems.

Process

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How It Works

HFO is stored in heated tanks to maintain fluidity. Before use, it is further heated and conditioned to reach the required viscosity for combustion.

In marine and industrial systems, fuel treatment systems ensure proper atomisation and combustion performance.

Delivery, storage, and usage must be aligned to ensure consistent fuel quality and operational reliability.

FAQ

What are the benefits of using HFO?

HFO is a cost-effective and widely available fuel with high energy output. It is particularly suited to heavy-duty applications such as marine engines and industrial boilers. Its stable storage properties allow for bulk storage over time when handled correctly, supporting consistent operations.

How is HFO stored and transported?

HFO is stored in large tanks designed to handle high-viscosity fuels. Heating systems are typically required to maintain flowability. Transport is carried out using specialised heated tankers or pipelines to ensure the fuel remains usable throughout the supply chain.

What environmental impact does HFO have?

Combustion of HFO produces emissions including sulphur oxides (SOx), nitrogen oxides (NOx), and particulate matter. These emissions are subject to regulatory frameworks, particularly in marine applications.  

To support customers in addressing emissions, we offer a carbon-offsetting scheme as an optional measure.

Is HFO compatible with existing machinery and systems?

Many industrial engines, boilers, and marine systems are specifically designed to operate on HFO. However, due to its viscosity and handling requirements, certain systems may require appropriate heating, treatment, or modifications. Equipment specifications should always be reviewed before use.

Are there alternatives to Heavy Fuel Oil?

Alternatives include liquefied natural gas (LNG), biofuels, and distillate fuels such as Marine Gasoil. These options differ in infrastructure requirements, cost structure, and operational suitability.  

Each business should assess which option aligns with its operational and economic requirements.

Can emissions be addressed without switching fuel?

In addition to evaluating alternative fuels, emissions can be addressed through measures such as carbon offsetting. This can be a first step or an option where direct fuel switching is not feasible within existing infrastructure.

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We provide clear supply options aligned with your operational setup.