Oldendorff commissioned study reveals issues with biofuels
A study commissioned by German bulk carrier company Oldendorff Carriers has found issues with the stability and degradation of second-generation advanced biofuel blends when stored in ships’ bunker storage tanks.
PHOTO: Oldendorff’s cargo vessel Edwine Oldendorff loading cargo at Albany, Australia before commencing its biofuel trial. Oldendorff Carriers
The study was conducted by the US-based Massachusetts Institute of Technology’s (MIT) Center for Bits and Atoms (CBA) on a B20 biofuel blend comprising 20% biofuel component derived from used cooking oil and 80% VLSFO.
The analysis and impact
The study involved the analysis of 15 samples of the B20 biofuel blend. It was conducted by “monitoring eight chemical parameters over an extended one-year period, under a variety of storage conditions,” Oldendorff says.
The parameters included density, viscosity, water and sediment and microbial contamination (MCB), among others.
Low levels of MBC were noted in all the samples after a month, which increased over time in samples when exposed to light.
The study warned that MBC can lead to “operational problems, including fouling of tanks, pipes and filters, tank corrosion, and fuel injection equipment damage.”
Meanwhile, oxidative degradation was noted in certain samples, with the study recommending the addition of antioxidants and regular monitoring.
Primary reason behind the instability
The presence of unsaturated fatty acids in biofuels makes them prone to oxidative degradation, which involves the disintegration of macromolecules when exposed to oxygen through the process of oxidation. The unsaturated fatty acids are inherently present in the vegetable oils and animal fats from which the biofuels are derived.
This has raised concerns about the stability and degradation of biofuel blends over time when stored in vessels’ bunker tanks compared to conventional marine fuels, the study revealed.
Another study highlighting the same issues
In June, a study on using biofuels onboard vessels conducted by the Mærsk Mc-Kinney Møller Center for Zero Carbon Shipping (MMMCZCS) also showed that the presence of unsaturated compounds in bio-diesels make them susceptible to oxidative degradation.
This is because unsaturated compounds have “weak carbon-hydrogen (C-H) bonds that can break, creating sites that easily react with dissolved oxygen to form peroxides that initiate the oxidation process,” the MMMCZCS study elaborated.
The MMMCZCS study goes on to say that while this “oxidative nature is beneficial from a biodegradability perspective,” it is an “undesirable characteristic from a fuel-quality standpoint.”
Testing data from Oldendorff’s bulk carrier using a biofuel blend was utilised by MMMCZCS while conducting the study.
The German bulk carrier company believes that the MIT study “will be valuable for both biofuel producers and users, assisting them in planning their bunker storage and maintenance systems accordingly over time.”
Oldendorff’s use of biofuel blends
Oldendorff considers biofuels as a drop-in fuel option for reducing greenhouse gas emissions (GHG) emissions.
In January 2022, the company trialled the B20 biofuel blend - supplied by oil supermajor BP - on its cargo vessel, Edwine Oldendorff. The trial voyage saw the vessel sailing from Australia to Vietnam carrying cargo for the Australian cooperative CBH Group. MIT analysed the emission reduction potential of the biofuel as part of its agreement with Oldendorff.
By Tuhin Roy
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