GENERATOR DAMAGE PAT SMYTH – LECTURER IN ADVANCED BIOFUELS, MCGILL UNIVERSITY, CANADA


Block Micelles damage to generator injectors


Micelles are a major factor in emergency generator damage, yet traditional filters do not remove them efficiently. Pat Smyth, lecturer in advanced biofuels for BioFuelNet Canada, outlines a better solution.


Micelles were recently recognised as the major factor in diesel corrosion and emergency generator damage. Micelles form when water droplets and surfactants bond together; the Micelles then settle to the storage tank bottom, forming a layer that is very conducive to microbial growth. Microbes create acids, which corrode components of backup generator engines, storage tanks (including fiberglass tanks), and piping. Micelles themselves are not efficiently removed by traditional filters, so they are ingested into engines, scouring injectors and greatly increasing the risk of backup generator failure. There is one filtration standard that


addresses Micelle removal, and that is SAE J1488 filtration.


Micelle formation Water and surfactants are both polar molecules, which means they both have an electrical charge, so are attracted to each other; Micelles form when surfactants and water bond, and the water droplet becomes encapsulated by surfactants. The Micelles then settle to the storage tank bottom, forming a layer that is conducive to microbial growth, and also concentrate the water and surfactants on the bottom layer. Some examples of surfactants include biodiesel and ethanol; practically every additive to liquid fuels is a surfactant. Figure 1 is a 3D illustration of a Micelle,


the surfactant encapsulates the water droplet, forming a surfactant shell. Note that a traditional filter needs physical contact with the water to remove it; in a Micelle, the surfactant’s fatty acid tail forms a barrier, isolating the water droplet from filter material, water tests, and fuel. Since the surfactant prevents contact between the filter and the water droplet, traditional filters cannot easily remove the water and


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Figure 1. Cutaway depiction of surfactant molecules encasing a water droplet.


most Micelles bypass the traditional filter. In 2021, the Coordinating Research


Council (CRC) released Project DP-07-16- 01 Identification of potential parameters causing corrosion of metallic components in diesel fuel underground storage tanks.1 CRC is a non-profit organisation that directs engineering and environmental studies on the interaction between automotive/other mobility equipment and petroleum products. The Sustaining Members of CRC are the American


Petroleum Institute (API), and a group of automobile manufacturer members (Stellantis, Mercedes Benz, Ford, General Motors, Honda, Nissan, Toyota, and Volkswagen). A key finding is Micelle formation (see


Fig 2). Pat Smyth


Pat Smyth has researched diesel corrosion control for over 12 years. In 2022 he was invited to present his findings to ASTM International (American Society for


Testing Materials) and to SAE International (Society of Automotive Engineers), as well as to NACE (National Association Corrosion Engineers) (2018) and the EPA Office of Underground Storage Tanks (2016). Pat is a lecturer in BioFuelNet Canada’s Advanced Biofuels course, hosted on McGill University’s myCourses platform.


Corrosion mechanism Details of corroded ULSD equipment are shown in Figure 3 and a UST system with steel tank with severe metal corrosion in Figure 4. Before the 2006


introduction of ULSD (Ultra Low Sulfer Diesel) and surfactants (biodiesel), free-standing water accumulated on the tank bottom, and microbes only existed in a thin layer at the water/diesel interface. This thin layer of microbes has been described as the thickness of a sheet of


IFHE DIGEST 2024


Surfactant molecules


Water droplet


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