A Computational Model for a Dilute Biomass Suspension Undergoing Mixing and Settling

Guest Speaker: Michael Sprague

Abstract: The biochemical conversion of lignocellulosic biomass to liquid transportation fuels involves a multitude of physical and chemical transformations that occur in several distinct processing steps (e.g., pretreatment, enzymatic hydrolysis, and fermentation). In this work we focus on development of a computational fluid dynamics model of a dilute biomass slurry, which is a highly viscous particle-laden fluid that can exhibit yield-stress behavior. Here, we model the biomass slurry as a generalized Newtonian fluid that accommodates biomass transport due to settling and biomass-concentration-dependent viscosity. Within a typical mixing vessel, viscosity can vary over several orders of magnitude. We solve the model with the Nek5000 spectral-finite-element code in a simple vane mixer, and validate against experimental results.

Michael Sprague is a Senior Scientist at the National Renewable Energy Laboratory. Mike’s research interests include computational mechanics of fluids, structures, and their interaction, spectral finite-element methods for time-dependent partial-differential equations, and high-performance computing. He is leading several projects in wind energy, including a Department of Energy (DOE) Exascale Computing Project.
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