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Accurate Characterization of Particle Flowability

Idaho National Laboratory

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Technology Marketing Summary

Efficient and reliable flow of bulk solids is of significant importance to a wide range of industries. Unfortunately, variables such as density, particle size, and moisture content of many bulk solid feed streams cause problems for accurately controlling their flow as required for various process. Formation of bridges, crusts, rat holes, and funnels in bulk solids handling equipment are often experienced causing the inefficient and unreliable flow in conventional equipment. These issues often result in process downtime, and damage to equipment. They are often addressed by making expensive equipment upgrades or investing in oversized handling systems. New cost effective methods and systems to accurately measure and control the flowability of bulk solids are needed to address these materials handling issues.



Researchers at INL have developed a simple measurement tool for the efficient and reliable characterization of the flowability of bulk solids via all four key parameters: bulk density, particle friction (cohesion), compressibility and elasticity. While many rheological testing devices have been deployed to assess flow properties of bulk solids no tester to date can accurately measure the effect of all four parameters on flowability at the same time. The concept includes a test apparatus and procedure for testing that also mimics flow in a gravity hopper to give direct prediction of flow problems within hopper systems.


  • Allows for thorough characterization of bulk solid flowability properties
  • Reduced capital expenditure in bulk solid handling equipment by designing “right size” systems
  • Cost effective
  • More versatile compared to conventional characterization methods  


Applications and Industries
  • Food
  • Cellulosic biomass handling and conversion
  • Biofuels
  • Agriculture
  • Mining
  • Other applications where bulk solid feed streams are variable or uncontrolled


More Information

Hernandez S, TL Westover, JC Ryan, AC Matthews, CL Williams. “Feeding properties and behavior of hammer- and knife-milled pine," Powder Technol. 2017; 320, 191-201

Westover TL, Phanphanich M, Ryan, JC. Comprehensive rheological characterization of chopped and ground switchgrass, Biofuels 2015; 6(5-6): 249-260.

Patents and Patent Applications
ID Number
Title and Abstract
Primary Lab
Patent 9,969,553
Hopper apparatuses for processing a bulk solid, and related systems and methods
A hopper apparatus comprises a movable wall comprising opposing walls movably connected to a support assembly and oriented at acute angles relative to a central vertical axis of the support assembly, and movement control devices configured and positioned to move the opposing walls along the support assembly to control dimensions of a discharge outlet at least partially defined by converging ends of the opposing walls; a liner assembly comprising liner structures at least partially overlying inner surfaces of the opposing walls and configured to remain at least partially stationary relative to the opposing walls during movement of the opposing walls; and pressure sensors between the inner surfaces of opposing walls and portions of the liner structures thereover. A bulk solids processing system and a method of processing a bulk solid are also described.
Technology Status
Technology IDDevelopment StageAvailabilityPublishedLast Updated

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To: Ryan Bills<>