Quantifying Mixing and Segregation In a Fluidized Bed with a Particle Segregation Number

Mixing and segregation in particulate systems have been studied extensively over the past two decades because multi-component granular systems are important to many industrial processes such as fluidized bed gasification, food processing, and pharmaceutical production. Product quality is often identified by the homogeneity (or lack thereof) of the mixture. Several methods have been developed to assess the mixing or segregation quality in granular systems and various segregation measures have been proposed. This paper presents a method to quantify mixing/segregation in collapsed fluidized beds by using 3D X-ray computed tomography. Additionally, a new characterization measure, the particle segregation number (PSN), is introduced. The PSN expresses the level of "mixedness" in a collapsed fluidized bed (or any granular system) with a single number, thus providing a single measure to quantify mixing or segregation in 3D granular systems.