(21e) Real-Time, in-Line Assessment of Flow Performance for Compressible and Anisotropic Bulk Solids
Feeding and handling problems have been recognized as a major contributor to low production of renewable cellulosic ethanol in the US, which achieved only 7% of nameplate capacity in 2016. Current methods that assess material feeding and handling properties require multiple hours to complete, making them ill-suited for quality assurance and control (QA/QC) in production environments. This talk presents a method, based upon a custom hopper with adaptable geometry, to assess feeding and handling behavior of materials in a production or receiving line in real-time, so that those properties can be used to either sort material or adjust preprocessing conditions to ensure that incoming material meet feeding and handling specifications. Flow properties are determined by continually adjusting the size of the outlet in a plane-flow hopper to maintain a constant fill level in the hopper. The angle of the hopper walls can also be adjusted to tune the geometry to different materials. Tests conducted at approximately 1,000 lbs per hour indicate that this method readily assesses the flow performance differences of corn stover and pine wood due to changes in particle size from 3 to 13 mm and due to changes in moisture content from 10 to 20%. Comparison of this method with shear tests using an automated Schulze ring shear indicate that this method is more sensitive for determining differences in flowability performance than traditional shear tests for corn stover and pine wood. Test results, including wall pressure measurements, are compared to simulations and indicate that this method shows promise for in-line quantitative estimation of the flow properties of compressible and anisotropic materials, including bulk density, cohesion, and internal angle of friction.