US-SOUTH AFRICA DDEP: EFFICIENT PROCESSING OF POLYDISPERSE PARTICULATE MIXTURES

Intellectual Merit: Particulate, or granular, materials are encountered throughout our daily lives, ranging from the food we eat, to the roads we drive on, to the medicines we take. It is challenging to find a commercial product that at some point was not a collection of differing, distinct particles before it was mixed and transformed into its final form. Yet, despite the prevalence of particulate materials, their processing units operate at meager levels compared to their fluid counterparts. As a result, particulate processing plants suffer from poor efficiency, frequent shutdowns and excess waste, all contributing to higher product cost. Often, rules-of-thumb have been used to limit these problems, but these have not reliably predicted and prevented processing problems from occurring. A more desirable approach is the ability to quantitatively predict flow behavior and segregation rates from fundamental principles, material properties and small-scale laboratory tests, and then to engineer processes accordingly to limit detrimental effects on performance and product uniformity. A multidisciplinary research team is critical to first characterize the fundamental nature of granular materials and then extend that knowledge to efficient operation at industrial scale. Collaboration among Professor Benjamin Glasser and Mr. Matthew Metzger at Rutgers University with the research group of Professor Diane Hildebrandt at the University of the Witwatersrand (WITS) in South Africa will uniquely connect the basic knowledge of granular materials with ability to design efficient granular operations at scale. At the core of these issues is the lack of a fundamental understanding of how particles behave when subject to a driving force, which significantly hampers attempts to reproduce and scale-up particulate processes. The proposed Doctoral Dissertation Enhancement Project will focus on developing a fundamental understanding of why granular materials tend to segregate, or de-mix. Investigations of the flow of polydisperse particles of varying degrees of roughness in commonly encountered granular systems will assist in building the foundation for intelligent decision making about the segregation potential of a variety of particulate mixtures. Subsequent analysis will determine operation regimes to minimize particulate segregation during industrial operation. Broader Impact: The collaboration will nurture a conduit of communication that will facilitate on-going and future exchanges between the two leading research groups in their respective fields. Prof. Glasser's group at Rutgers University is internationally recognized for foundational works exposing links between the tendency of granular materials to segregate and instabilities caused by differences in size, density and surface properties. Prof. Hildebrandt?s group at WITS University offers complementary expertise in incorporating elementary knowledge into the design of efficient processes from a systems perspective. Collectively, the collaboration will connect internationally-renowned scientists and expertise not found at a single university. The proposed studies will develop a framework to determine optimal operation conditions for granular unit operations to decrease the occurrence of product failures and inefficiencies frequently encountered during particulate processing operations.This award has been funded by NSF's Office of International Science and Engineering.