Biomass Particle Models with Realistic Morphology and Resolved Microstructure for Simulations of Intraparticle Transport Phenomena
Peter Ciesielski, Michael F. Crowley, M R. Nimlos, Aric W. Sanders, Gavin Wiggins, Bryon Donohoe
Biomass exhibits a complex microstructure of directional pores that can vary substantially between species of origin. However, models of biomass particles employed in simulations of conversion processes typically employ over-simplified geometry such as spheres and cylinders that neglect intra-particle microstructure. Here we develop 3D models of biomass particles with size, morphology, and microstructure based on parameters obtained from quantitative image analysis. We obtain measurements of particle size and morphology by analyzing large ensembles of particles that result from typical size reduction methods, and we delineate several representative size classes. Microstructural parameters including cell wall thickness and cell lumen dimensions are measured directly from micrographs of sectioned biomass. A general constructive solid geometry algorithm is presented that produces models of biomass particles based on these measurements. Finally, we employ the parameters obtained from image analysis to construct models of 3 different particle size classes from two different feedstocks representing a hardwood poplar species (Populus tremuloides, quaking aspen) and a softwood pine (Pinus taeda, loblolly pine).