![]() ![]() Poor understanding of biomass handling, especially with regard to biomass flowability during feedstock conversion process design, may result in excessive process downtime due to common granular material interactions such as unanticipated feed silo ratholing, screw feeder jamming, etc. However, handling of biomass feedstock is one of the key challenges to the commercialization of biomass as an energy source. Biomass is considered one of the most abundant and easy-to-access alternative renewable resources of energy and chemicals ( Binder and Raines, 2009 Bilgili et al., 2017). Comparatively, the auger feeder was found to be much more impacted by the size of the particles, where smaller particles had a more consistent and stable flow while consuming less power.ĭue to the limited resource of fossil fuel and growing sentiment toward global warming, alternative sources of energy are today’s demand. For the gravity-driven hopper flow, the critical arching distance and mass discharge rate ranged from approximately 10 to 30 mm and 2 to 16 tons/hour, respectively, for both materials, where the arching distance depends strongly on the overall particle size and depends less on the hopper inclination angle. To supplement these laboratory-scale properties, this work explores the flow of loblolly pine and Douglas fir through a pilot-scale wedge-shaped hopper and a screw feeder. Measurement of the anisotropic particle–particle friction ranged from coefficients of approximately 0.20 to 0.45 and resulted in significantly higher and more variable friction measurements for larger particle sizes and in perpendicular alignment orientations. For equipment designed to characterize the quasi-static shear stress failure of bulk materials ranging from 50 to 1,000 ml in test volume, similar test results were observed for finely milled particles (50% passing size of 1.4 mm) with a narrow size distribution (span between 10 and 90% passing size of 0.9 mm), while stress chaining and over-torque issues persisted for the bench-scale test apparatus for larger particle sizes or widely dispersed sample sizes. In general, it was observed that the bulk internal friction and apparent cohesion depend strongly on both the stress state of the sample in granular shear testers and the overall particle size and distribution span. This work explores the shear and frictional properties of loblolly pine at multiple experimental test apparatus and particle scales to elucidate a property window that defines the shear behavior over a range of material attributes (particle size, size distribution, moisture content, etc.). ![]() ![]() Current handling unit operations are adapted from other sectors (primarily agriculture), where some simplifying assumptions about granular mechanics and flow performance do not translate well to a highly compressible and anisotropic material with nonlinear time- and stress-dependent properties. One dominant challenge facing the development of biorefineries is achieving consistent system throughput with highly variant biomass feedstock quality and handling performance. 4Material Physics Applications Division, Los Alamos National Laboratory, Los Alamos, NM, United States.3Applied Materials Division, Argonne National Laboratory, Lemont, IL, United States.2Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, WA, United States.1Energy and Environment Science and Technology Directorate, Idaho National Laboratory, Idaho Falls, ID, United States.Jordan Klinger 1*, Nepu Saha 1, Tiasha Bhattacharjee 1, Susan Carilli 1, Wencheng Jin 1, Yidong Xia 1, Richard Daniel 2, Carolyn Burns 2, Oyelayo Ajayi 3, Ziwei Cheng 4, Ricardo Navar 4 and Troy Semelsberger 4 ![]()
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