Tackling marine diesel engine fuel contamination

In the marine industry, where fuel quality and operational continuity are crucial, understanding water contamination is essential. It’s a persistent issue for shipping operators, degrading fuel quality and damaging fuel systems – and ultimately leading to costly disruptions in a vessel’s performance.

Contaminants including microbiological growth, Hormoconis resinae (the dreaded diesel bug), fungi, yeasts, water, and excessive sulphur can all render the fuel supply unusable if left untreated.

Then there’s the significant havoc that degraded fuel can wreak on onboard fuel systems, resulting in reduced performance, increased maintenance costs, and even potential non-compliance with environmental regulations.

The last things you need are corrosion, clogged filters, engine inefficiency, and even equipment failure causing further problems on top of any fuel wastage.

How to protect your marine fuel against contamination

Proper fuel management, including regular testing and treatment, is crucial for addressing these challenges.

Here, we’re going to unpack the causes of marine fuel contamination and explore strategies for detection, prevention, and mitigation. With a proactive fuel stewardship strategy you can:

• maintain the integrity of your onboard fuel
• regularly test for contaminants and monitor quality
• take steps to treat any contamination to mitigate damage 

What causes marine fuel contamination?

Water – a hidden threat

Microorganisms, including bacteria and fungi, thrive in environments where water and nutrients are both present. Water can enter the fuel system through condensation, poor handling practices, or compromised storage.

Biofuels and contamination

The marine industry is increasingly turning to biofuels as an effective way to decarbonise and reduce environmental impacts, thanks to their low sulphur levels and reduced CO2 emissions. This shift aligns with stricter regulations, such as the IMO 2020 mandate that lowered the sulphur content in ship fuel oil to 0.5% from 3.5%.

The downside is that biofuels such as FAME (Fatty Acid Methyl Ester) can promote microbial growth and fuel contamination, as they attract and hold more water, creating better conditions for the growth of diesel bug.

This is a challenge vessels must navigate as they balance regulatory compliance with the practicalities of keeping their fuel clean and their operations running smoothly – making managing and mitigating microbial contamination even more crucial.

Risks of contamination in the fuel supply chain

There’s potential risk at every stage of the supply chain, including fuel production, distribution, storage and in the fuel systems of end users – as shown in the diagram below (zoom in for a closer look).

Common signs of onboard fuel contamination

Engine performance issues:

• Reduced power output and/or engine efficiency
• Reduce
• Difficulty starting the engine
• Unexpected engine shutdowns

Fuel system problems:

• Clogged fuel filters
• Fuel injector failures
• Increased fuel consumption
• Failing fuel pumps

Increased maintenance needs:

• More frequent cleaning of engine components
• Higher frequency of component replacements

Engine component wear:

• Increased piston ring wear
• Increased cylinder liner wear

Visible fuel changes:

• Unusual colour or cloudiness
• Presence of sediment or particles
• Separation of fuel layers

Unusual odours:

• Strong, unfamiliar smells from the fuel
• Exhaust odour changes

Increased emissions:

• Excessive smoke from the exhaust
• Changed colour of exhaust smoke

Water in fuel:

• Condensation in fuel tanks
• Fuel-water emulsion formation

Microbial growth:

• Slimy substances in fuel or filters
• Biofouling in storage tanks

Corrosion:

• Accelerated wear on fuel system components
• Visible corrosion in fuel tanks or lines

Fuel test results:

• Failed laboratory analysis
• Abnormal readings on onboard fuel testing equipment

Inconsistent fuel gauge readings:

• Erratic or inaccurate fuel level indications

Lubricating oil degradation:

• Increased acidity in lubricating oil
• More frequent oil changes required
• Potential bearing damage due to oil breakdown

Comprehensive fuel stewardship solutions for the marine industry

At Star, we understand the impact of fuel contamination on the efficiency and reliability of your marine operations. We’ve developed a range of solutions that addresses these challenges and covers the full cycle of fuel management.

Fuel maintenance & contamination prevention

Don’t leave your fuel quality to chance. Good fuel stewardship is essential for maintaining reliable performance and protecting your valuable assets, by preventing the buildup of harmful deposits and sludge

Your solutions…

Aquafighter fuel tank filters

Simple yet effective, these filters capture and remove free and emulsified water in directly in the fuel tank to prevent diesel bug, and protect the tank and filters. Various sizes and shapes to suit tank openings, sizes & configurations are available.

Star Mariner fuel maintenance additives

Our range of marine fuel treatment additives are designed to protect the integrity of fuel on-board ship, and are effective with Marine Gas Oils (MGOs) and low sulphur alternatives, acting to neutralise and prevent contamination, improve shelf life and counter temperature induced coagulation.

Fuel contamination testing & analysis

Onboard testing identifies any problems at the point of refuelling and at sea, meaning contamination risks can be minimised and suppliers held to account. This helps to avoid unnecessary downtime and costly long-term damage to hardware.

Your solutions…

Star FUELSTAT contamination test kit

An on-board testing solution that detects Hormoconis resinae (diesel bug), bacteria, fungi and yeast contaminants in as little as 10 minutes.

Star XRF onboard sulphur tester

Our on-board analyser confirms sulphur content in fuel within a range of 0.1% – 5.0%, allowing validation of fuel for vessels operating within and outside of designated Emission Control Areas (ECAs).

Fuel treatment

If the worst happens and your fuel becomes compromised, we can offer a range of additives to tackle it and protect against degradation.

Your solutions…

Star Mariner fuel treatment additives

Star Mariner Eliminator is a biocide that eradicates and prevents microbial contamination of fuel (diesel bug).

Fuel treatment services

We offer an all-inclusive approach to ensuring onboard fuel quality, delivered by expert technician’s on-board ship. This includes: fuel sample analysis, fuel polishing and conditioning; and fuel tank & system cleaning.

Contact us today to find out more.