Particle Design for Improved Flow

Chair(s):

• Heather Emady, Arizona State University

Schedule

Abstracts

Controlling Segregation by Particle or Process Designs through Fundamental Understanding

Yi Fan¹, Richard Lueptow², Bruce Hook^1*, and Karl Jacob³;  ¹ The Dow Chemical Company, Lake Jackson, TX, 77566; ² Northwestern University, Evanston, IL; ³ Retired from The Dow Chemical Company, Midland, MI, 48677

Particulate products tend to segregate due to size differences of different components when handled, processed, or transported in a variety of industries ranging from chemical to pharmaceutical to agricultural. Segregation can cause unwanted product quality issues or process upset, resulting in significant financial losses due to the need of remixing these products or off specs products. There are many different mechanisms for particle size segregation including sifting/percolation, angle of repose, bouncing, and fluidization, where the sifting and percolation mechanism is the most prominent driving mechanism for granular materials above 200 microns.  This talk presents an approach to control segregation of granular materials by properly designing particles (e.g. size or shape) or process conditions based on a recently developed continuum model [1], where particle properties and process conditions are incorporated.  A few examples are presented to show how particle size, size distribution, and shape can be modified or process conditions such as feed flow rates can be regulated to minimize segregation. In a rare case, we also show an example of how the approach can be used to optimize process conditions to utilize segregation to achieve better process efficiency and product quality.  

[1], Y. Fan, C. Schlick, P. Umbanhowar, J. Ottino, and Lueptow, “Modelling size segregation of granular materials: the roles of segregation, advection and diffusion”, Journal of Fluid Mechanics 741, 252-279, 2019.

Improving Flowability by Designing Powders

Jayant Khambekar, Jenike & Johanson

In many industrial applications, storage and flow of powdered materials are often encountered.  Powder flowability is a function of the powder itself as well as of design of the equipment used to handle it.  These are the two sides of the same coin; you can achieve better flow behavior by using either approach.  Thus, it is quite possible to design powder characteristics in order to achieve good flow behavior.  This presentation will discuss various powder characteristics that play a role in determining flow behavior, and also demonstrate by giving examples from industrial applications.