Faculty members and students from the UMass Amherst departments of chemical and mechanical and industrial engineering recently collaborated with University of Minnesota researchers to discover a new behavior of woody biomass that makes it levitate above heated surfaces in a way similar to what is called “the Leidenfrost effect” in liquids. Announced in Nature Scientific Reports, the research captures via high speed photography a particle of cellulosic biomass floating above a surface by aggressive generation of gases. The surprising new property can enhance biofuel production and has implications for cooking, tobacco use, and forest fire suppression. Read Phys Org article.
The UMass faculty members involved in the research were Jonathan Rothstein of the Mechanical and Industrial Engineering Department and Wei Fan of the Chemical Engineering Department, and they were supported by UMass undergraduate students Katharine Greco, Michael Stelatto, Eric Davis, and Brendon Vincent. Their main collaborator was former UMass Chemical Engineering Professor Paul Dauenhauer, now at the University of Minnesota Department of Chemical Engineering and Materials Science, who calls the find “an important discovery.”
As the article in Nature Scientific Reports explains, “The condition of heat transfer to lignocellulosic biomass particles during thermal processing at high temperature (>400 °C) dramatically alters the yield and quality of renewable energy and fuels. In this work, crystalline cellulose particles were discovered to lift off heated surfaces by high speed photography similar to the Leidenfrost effect in hot, volatile liquids. Order of magnitude variation in heat transfer rates and cellulose particle lifetimes was observed as intermediate liquid cellulose droplets transitioned from low temperature wetting (500–600 °C) to fully de-wetted, skittering droplets on polished surfaces (>700 °C). Introduction of macroporosity to the heated surface was shown to completely inhibit the cellulose Leidenfrost effect, providing a tunable design parameter to control particle heat transfer rates in industrial biomass reactors.”