Released October 5, 2010
MOSCOW, ID – After biodiesel is made, it must be cleaned to remove impurities, including soap and glycerin. The traditional water wash method causes several problems, including possible emulsions and degraded biodiesel if the fuel is not dried adequately. It also creates a lot of waste water.
Recently, waterless methods of purifying biodiesel have been introduced into the marketplace, such as ion exchange resins and synthetic magnesium silicate.
A number of different companies manufacture ion exchange resins (which are small polymer beads) to clean biodiesel. Although the products are similar, the companies’ explanations of how the products work are sometimes very different. For example, many companies say the beads work by exchanging ions (the sodium or potassium ions from the soap in the biodiesel are exchanged with hydrogen ions on the bead surfaces). However, one company selling similar beads claims they work via glycerin and soap interaction.
University of Idaho graduate student Jake Wall worked with Dr. Jon Van Gerpen and Dr. Joseph Thompson to conduct a series of experiments on ion exchange resins to determine how they work, including how long they remain effective.
Read the complete Tech Note at the University of Idaho's Biodiesel Education Program web site.
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