Will Mass Flow Solve All Your Segregation Problems?

Most chemical processes must produce products that are uniformly mixed. There have been many articles written about preventing particle segregation during bulk solids flow; and ensuring a mass flow pattern is a common suggestion. But mass flow alone is not necessarily the answer to all segregation problems that can occur in silos and tanks. We will focus on the two major mechanisms of segregation; namely, sifting and fluidization segregation.   Determine the segregation mechanism The first step in solving segregation is to determine what type of segregation is occurring in your vessel. The two most common types of segregation are sifting and fluidization segregation. The first step is to know your material’s flow properties. The next step is to identify the mechanism that is causing your segregation and provide reliable geometries and solutions that will result in segregation-free flow. Laboratory tests can be run to identify how a solid will flow. Many of these tests follow an ASTM standard [1] that uses the Jenike method of testing your materials [2]. The results of material testing will help you determine what type of segregation you have to overcome so that you can design a silo or hopper to store and discharge your…