AZoSensors discusses the importance of fuel analysis in the marine industry, the common contaminants found in marine fuel and their associated effects, as well as the methods used to test marine fuel.
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Why is Fuel Analysis Important to The Marine Industry?
Using contaminated or off-specification fuels can adversely affect the environmental and operational performance and safety of marine vessels, increasing the risk of costly downtime. Operational issues and downtime due to poor fuel quality result in significant financial losses for ship operators and associated stakeholders every year.
For instance, biofouling is a significant issue with marine diesel fuel as it increases the risk of microbial contamination. Similarly, water contamination is another problem in both heavy fuels and marine diesel fuels.
Thus, fuel analysis is necessary to ensure the use of uncontaminated marine fuel and optimize the ship's performance. Fuel analysis can prevent engine damage and failure, reduce replacement and maintenance of parts, and decrease re-fuelling and de-bunkering due to poor fuel quality.
Additionally, fuel analysis can ensure the use of on-specification fuels and compliance with insurance underwriter requirements and global regulations and directives with limited operational impact.
Common Contaminants in Marine Fuel
Common contaminants in marine fuel include asphaltenes, hydrogen sulfide, sulfur, nitrogen, carbon, vanadium, nickel, aluminum silicate, water, ash, sediments, used lubricating oil, and microbes, including yeast, fungi, and bacteria. The presence of sulfur in marine fuel leads to rapid wear in engines owing to its acidity and generation of sulfur oxides on combustion.
Sulfur oxides must be neutralized using cylinder lubricants as they are corrosive to engine piston liners. Organic compound additives can be used to control the acidity caused by sulfur.
Similarly, water in fuel translates into energy loss for the user as water does not yield any energy. Moreover, water-contaminated fuel in injectors can result in erratic combustion. Water can also cause corrosion to different components.
The total sediment aged is primarily the total sediment formed under typical conditions in the marine fuel excluding external influences. In fuel oil, the total sediment aged can cause problems in the fuel cleaning systems when it exceeds the specification value. Higher total sediment aged also leads to plugging in the fuel filters and erratic combustion.
The presence of aluminum silicate can lead to abrasive wear of fuel pumps, injectors, and cylinder liners. Thus, the aluminum silicate level must be limited to enable the fuel cleaning system of the ship to remove the contaminant effectively. Ash content indicates the share of inorganic incombustible components present in marine fuel.
Microbiological contamination occurs when the temperature ranges between 15 oC and 40 oC and non-dissolved water is present in the fuel. This type of contamination is prevalent in sub-tropical and tropical regions due to high ambient temperatures and air humidity. Microbiological contamination can lead to the plugging of filters on marine distillate fuel feed and gasoil lines.
Methods Used for Marine Fuel Testing
Sophisticated methods such as gas chromatography-mass spectrometry (GCMS) and Fourier transform infrared (FTIR) spectroscopy are used to perform a thorough analysis of marine fuel composition.
FTIR can be utilized to characterize organic components such as polymers, ketones, alcohols, and acids. The components are identified by comparing the resulting spectra to a library that contains spectra of known components. However, all components, such as acids, cannot be effectively identified by FTIR, which necessitates further analysis, such as GCMS.
The GCMS generates a detailed spectrum showing all detected components, which are then identified by comparing them to a library of known spectra. The concentration of every component is obtained by its signal strength.
However, these steps are time-consuming, triggering the emergence of fast screening methods such as headspace GC-MS (HS GCMS) that can deliver results within a few hours. These methods can only identify more volatile components that can be separated from the marine fuel within a short duration.
The International Organization for Standardization (ISO) 8217 prescribed methods for aluminum silicate testing are ISO 10478, IP 501, and IP 470. These tests measure the sum of aluminum and silicon in marine fuel as the ratio between aluminum and silicon can vary significantly between manufacturers and types of aluminum silicate catalysts.
Micro carbon residue is an ISO 8217:2005 prescribed test used to test the carbon residue in marine fuels. Micro carbon residue is more precise and quicker than other tests, such as Conradson Carbon Residue. The total sediment is measured by hot filtration on all lower-grade marine fuel products that fail the visual inspection requirements.
Sensors Used in Marine Fuel Testing
Over the years, there have been significant advancements in sensors used for marine fuel testing. Sensors have revolutionized machinery monitoring, measuring various parameters, and identifying risks, which has led to improved efficiency and compliance.
Various sensors, including echo sounders, viscosity and density sensors, and torque meters, help optimize marine fuel efficiency. For example, viscosity and density sensors measure the viscosity and density of marine fuel, which helps detect contaminants and monitor fuel quality in real-time, thus satisfying regulatory sulfur content requirements.
Advanced sensor technologies offer benefits such as data accuracy, early detection of contaminants, and remote monitoring, making maritime infrastructures more efficient and safer.
Sensors to Monitor Fuel Contamination: The Future
It is clear that contaminated fuel severely impacts the productivity and success of the marine industry. Interest from academia is helping to address the risks of contaminated marine fuel, with some recent research examples discussed below.
A recent study published in Sensors discussed a system equipped with a mini sensor that sniffs ship exhausts. This device helps detect SO2 in marine fuel and monitor vessel emissions, thus reducing ship pollution. The measurement accuracy of this device was verified by on-site tests.
Another recent study published in Ocean & Coastal Management proposed a sensing method for monitoring marine fuel sulfur content (FSC) in ships. This method combines sensor observations with SO2 numeric simulation to determine FSC. This technique enables efficient supervision of contaminants in marine fuels and ship emissions.
References and Further Reading
Prevention of Water and Contaminants In Marine Fuel Systems. [Online]
Vermeire, M. B. (2021). everything you need to know about marine fuels. [Online]
Investigative Analysis of Marine Fuel Oils: Pros & Cons. [Online]
Be assured of your marine fuel quality. [Online] Available at: https://www.lr.org/en/services/technical-advisory/fuel-testing/
Deng, M., et al. (2022). A Diffused Mini-Sniffing Sensor for Monitoring SO2 Emissions Compliance of Navigating Ships. Sensors, 22(14), p.5198. doi.org/10.3390/s22145198
Peng, X., et al. (2022). Optimal site selection for the remote-monitoring sulfur content of ship fuels in ports. Ocean & Coastal Management, 225, p.106211. doi.org/10.1016/j.ocecoaman.2022.106211
Simon Gregory, (2023). Advancements in Sensor Technology for Marine Fuel Testing. Available at: https://www.pibeginners.com/marine-fuel-testing/
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