Particle Professor: Shape up
Particle shape can be important when you're designing a new process or fixing an existing one. It may be necessary to understand your particle shape, how it changes throughout the process, and how it will affect your process and product.
All too often we assume that a particle's shape is spherical. Sometimes this assumption can have undesirable consequences. Particles that aren't spherical increase the particle-to-particle shear force and the gas- or fluid-to-particle drag force. This means nonspherical particles could make your particle size measurements incorrect and your hopper flow more challenging, skew your grade efficiency curves in classifiers, increase your entrainment rate in fluidized beds, and increase your particle attrition in many unit operations. If you think you have nonspherical particles in your process, you need to follow these three steps: measure, evaluate, and apply.