Protecting onshore diesel assets from risks associated with biofuels

Greenhouse gases (GHGs) are a global problem. As the planet heats up, we must find every way to reduce the carbon footprint. Looking ahead, many projects are working to find zero-carbon solutions using new energies, but while waiting for these developments and the necessary infrastructure to support this energy transition, we must find ways to reduce GHGs, including emissions from current fuel emissions.

More efficient machines, which consume less fuel, and changes in fuel composition, incorporating more environmentally friendly components, are two of the weapons in our “arsenal” for a greener world. The challenge we face, however, is that while biofuels reduce emissions, they also pose an increased risk of damage to valuable terrestrial assets.

Biofuels and biodiesel have been around for a long time. The sale of E10 petrol and B7 diesel became mandatory in the European Union (EU) in 2011. B7 diesel contains up to 7% biocomponents derived from renewable resources, which are generically referred to as fatty acid methyl esters (FAME). We understand the limitations of this fuel at lower temperatures; however, the addition of FAME also gives it a greater affinity for retaining water.

Water, essential to life… and to microbes

We already know that water will separate from fuel and the steps to remove it are part of good fuel management. However, with the introduction of FAME into its chemical composition, the biofuel will retain water at higher concentrations, and the more FAME added, the greater the potential for emulsified water.

At the refinery, fuel contains

Water ingress comes from mechanisms such as condensation. As fuel is consumed and air takes its place in a tank, it brings moisture with it. Any change in temperature can cause this moisture to condense to create free water. Dissolved water and free water will chemically react with the FAME to form an emulsion at higher concentrations.

Let’s be clear, the use of biodiesel is an essential part of reducing GHGs and increasing the FAME content is an essential part of our efforts to reduce the environmental impact of diesel fuel emissions as new energies are developed. However, the additional water potential that accompanies biodiesel is problematic. The fuel is likely to contain dormant microbial formations, such as spores. The presence of water and air creates an environment where microbes (yeasts, filamentous fungi or bacteria) can thrive.

As the microbes multiply in the fuel, they can form a layer of biomass made up of billions of organisms. This biomass, which appears as a stringy web-like substance, usually gray or brown in color, can clog filters, increase injector wear, and even corrode tanks with the organic acid it contains. product. This was a problem even before FAME was introduced, but the bio component in the fuel has exacerbated the problem.

Risks for terrestrial assets

The increased percentage of FAME helps the environment but also increases the risk of microbial contamination. Additionally, technological advancements in motor technology also make these precision-engineered machines more susceptible to the risk of microbial contamination. The engines have precise, higher internal pressure fuel injectors, whose smaller orifices have a lower tolerance to sediment and particulates that could be generated by off-spec fuel. This requires better fuel management measures to ensure valuable equipment is not damaged and huge costs are incurred.

A Environmental Protection Agency (EPA) study suggests that moderate to severe corrosion on metal components of underground storage tank (UST) systems storing diesel fuel in the United States could be a very common phenomenon. The study found that 83% of the tanks inspected had moderate or severe metal corrosion and indicates that the introduction of biodiesel into USTs has resulted in an increase in corrosion issues by approximately 40% to 50%. This has a huge impact on downtime, including the need to replace system parts or even entire systems. A system will always fail at its weakest link, and although these are relatively cheap parts, the impact on businesses could be huge.

The report goes on to say: “Prior to 2007, the corrosion risks identified in tanks storing diesel fuels were generally considered to be limited to the bottom of the tanks…Corrosion observed since 2007 may however affect owners who have followed the same practices of maintenance. for years and had no corrosion problems.

Although typical maintenance may include testing, monitoring via sensors, sampling or fuel “polishing”, depending on the nature of the application, to avoid costly repairs and unnecessary tank cleaning, on-site testing provide an economical and quick way to determine microbial activity levels. in fuel. It showcases a proactive solution that, with an increasing percentage of FAME, will ensure users are one step ahead of any issues that may arise.

A research paper Posted in Frontiers in microbiology concluded, “A mixed microbial community of filamentous fungi and acid-producing bacteria was able to proliferate in B20 biodiesel storage tanks, cause fouling, degrade fuel by metabolizing FAME, produce organic acids, and accelerate corrosion. steel under biofilms attached to metal surfaces. ”

Corrosion not only threatens day-to-day operations, but also poses a significant environmental risk if fuel leaks into the ground.

The EPA notes that biodiesel may contain glycerol as a by-product of the production process and that “metabolic consumption of glycerol by microbial populations could produce volatile organic acids such as propionic, lactic, or glyceric acids.” These acids were identified in the majority of water samples from the aqueous phase of the fuels analyzed.

On-site testing saves time, money and produces accurate results

A good on-site testing regime will help ensure that contamination does not lead to corrosion or damage to systems. Understanding contamination levels means that maintenance actions, such as tank cleaning and biocide addition, can be adapted and optimized to avoid unnecessary costs.

Operators have two basic options when it comes to sampling to identify microbial contamination: send fuel samples to laboratories or use on-site test kits. Testing frequency may be adjusted based on microbial test results, observed trends, and operational experience. Microbes are living, dynamic organisms. This means that the microbial population can change during sample transport and as such laboratory testing requires careful storage and transport of samples and carries a higher risk that results will not be representative of the environment. tank environment.

On-site testing of land assets offers a quick, easy and cost-effective alternative. Antibody-based test kits, such as the Conidia Bioscience FUELSTAT Test Kit, are a proven method for identifying microbes capable of degrading fuel and providing an accurate indication of contamination levels. The kits are inexpensive, single-use, and testing is a straightforward process, requiring minimal training and no special handling. The simple nature of this approach means the task can be easily incorporated into day-to-day operations with results available within minutes.


The introduction of biofuels with increased FAME content makes sense for the environment, but we must not ignore the increased risk of microbial contamination and must adapt routine operations to ensure that advanced corrosion and damage to system components does not occur. threaten business continuity and profits.

To protect onshore assets, fuel management regimes need to be updated to reflect the increased risk of microbial contamination due to higher FAME content. Contamination can occur at any point in the fuel supply chain and simple on-site testing can save thousands in repairs and help protect the environment from fuel leaks.

Pierre Poitras is a technical consultant at Conidia Bioscience.