Lignocellulose is a continually mass-produced biopolymer composite that holds tremendous potential as a renewable source of fuels, chemicals, and materials that can displace large portions of fossil fuel-derived products. Realizing cost-competitive processes that convert lignocellulosic biomass into these desired products requires development of conversion strategies that specifically address its inherent complexity that spans multiple length scales. Such technological advances are informed by improving our fundamental understanding of the chemical, physical, and biological characteristics that govern the properties and functionality of lignocellulose in plant cell walls. Towards these goals, computational tools provide an excellent complement to experiment for the purposes of optimization and interpretation of experimental results. While much attention has been devoted to modeling biomass structure and behavior during conversion processes at the extreme length scales (i.e., the molecular scale and the bulk process scale), relatively little effort has been focused on understanding the role of lignocellulose mesostructure via computational modeling. Well established tools exist for modeling biomass at extreme scales, such as molecular dynamics simulation at the molecular scale and reactor models for the bulk process scale; however, few tools are available that can adequately account for the complex, highly variable geometry of lignocellulose at the mesoscale. In this presentation, I will describe our recent efforts towards elucidating the impact of lignocellulose mesostructure on physiochemical processes of great importance to many conversion processes, namely the transport of heat and mass throughout the cell wall. A general method based on constructive solid geometry will be presented that can be used to explicitly model lignocellulosic biopolymer assemblies on the length scale of ~ 100 nm. Several examples of how quantitative microscopy and chemical analysis can be used to parameterize the model for various scenarios will be included. Next, I will show how these structural models can be employed in finite element simulations to predict the transport behavior of heat and/or various chemical species throughout the material. Finally, I will describe how findings at this scale can be coupled to particle-scale simulations to provide estimates of useful parameters for the optimization biomass conversion processes.

Modeling the mesoscale architecture of lignocellulose to elucidate its impact on transport phenomena and biomass conversion processes

253rd National Meeting (2017)

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