Reactive Liftoff of Crystalline Cellulose Particles

Abstract

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.

Identification of the fractions responsible for morphology conservation in lignocellulosic pyrolysis: Visualization studies of sugarcane bagasse and its pseudo-components

“…Much of the sample has already been consumed by evaporation of the liquid phase, but a solid material remains on the surface. This is likely due to the fact that the material is in poor contact with the disk surface due to Leidenfrost effects [82], in which the vapors rise solid sample, drastically reducing the rate of energy transfer by conduction (see Frames C-D).…”

Micro-ratcheted surfaces for a heat engine biomass conveyor

“…15 More recently, intermediate cellulose liquids were revealed to exhibit a 'reactive Leidenfrost effect,' whereby the droplet of molten cellulose levitates above polished silicon surfaces at temperatures exceeding 750 1C. 16 In this work, we demonstrate the first capability to control the behavior and motion of microcrystalline cellulosic particles using engineered surfaces at the conditions common to thermochemical reactors. As depicted in the photograph of Fig.…”

High resolution mass spectrometry to explore molecular-level understanding of biomass pyrolysis

“…34 Dauenhauer and coworkers used high speed photography to visualize aerosol ejection from molten cellulose as well as a wetting effect in crystalline cellulose particles at fast pyrolysis temperatures (around 500 °C). [35][36] Most recently, the Dauenhauer group developed a thermal pulsing reactor, named the Pulse-Heated Analysis of Solid Reactions (PHASR).…”