Applications and associated processing technologies of lignocellulosic biomass are becoming increasingly important as we endeavor to meet societal demand for fuels, chemicals, and materials from renewable resources. Meanwhile, the rapidly expanding availability and capabilities of high-performance computing present an unprecedented opportunity to accelerate development of technologies surrounding lignocellulose utilization.In order to realize this potential, suitable modeling frameworks must be constructed that effectively capture the multiscale complexity and tremendous variety exhibited by lignocellulosic materials. In our assessment of previous endeavors toward this goal, several important shortcomings have been identified: (1) the lack of multiscale integration strategies that capture emergent properties and behaviors spanning different length scales and (2) the inability of many modeling approaches to effectively capture the variability and diversity of lignocellulose that arise from both natural and process-induced sources. In this Perspective, we survey previous modeling approaches for lignocellulose and simulation processes involving its chemical and mechanical transformation and suggest opportunities for future development to enhance the utility of computational tools to address barriers to widespread adoption of a renewable bioeconomy.

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The discharge of granular media from hoppers plays a vital role in many solids handling operations. The dynamic flow of poly-disperse non-spherical particles differs markedly from mono-disperse spheres and highlights the need to rigorously account for particle shape effects. The multi-sphere discrete element method (MS-DEM) was utilized here to examine the bulk packing fraction, discharge rate, collisional stress tensor, and order parameter of a bidisperse sphere-rod mixture evacuating a hopper. A modified form of the Myers and Sellers correlation with variable shape factor is capable of replicating the MS-DEM discharge data. The collisional stress tensor is observed to be highly symmetric for mono-disperse spheres but becomes asymmetric when rod-like particles are introduced. The order parameter within the hopper increases significantly during discharge and the rod-like particles undergo shear induced alignment with their long dimensions orthogonal to the outflow plane.