At the 2014 AIChE Student Conference held from November 14 - 17, 2014 in Atlanta, Georgia, junior Jacob D. Massa placed second, and senior Ingrid J. Paredes placed first, in their divisions of the Undergraduate Poster Competition. Both Massa and Paredes conduct research in Catalysis and Reaction Engineering. Under the guidance of Professor Benjamin Glasser, Paredes studies the the scale-up of rotary calcination, a common thermal treatment process in catalyst manufacturing, and under the guidance of Professor Fuat Celik, Massa studies the effect of platinum tin alloy structure and composition on the kinetics and thermodynamics of dehydrogenation and coke formation.
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The students' full abstracts can be read below:
Ingrid J. Paredes - "Residence Time Distribution Studies on a Rotary Calciner with Flights"
Rotary calcination is a thermal treatment process poorly understood, yet commonly used in catalyst manufacturing. Problems arise particularly upon scale-up of the process from the laboratory and pilot plant scales to the manufacturing scale. Developing such fundamental understanding of rotary calcination can improve product quality and cut energy and material costs. The two important indices for continuous calcination are: (1) in the axial direction, the residence time of the particles inside the calciner, and (2) in the radial direction, the characteristic time of calcination. This research seeks to provide a methodology for scale-up through understanding of the effects of calciner geometry, operating conditions and material properties on particle residence time and temperature distributions. To optimize calciner performance, the particle residence time must exceed the time required for heating and calcination. For uniform treatment, the particles must also exhibit low axial dispersion. A combination of discrete element method (DEM) simulations and experiments are used to explore the influence of these competing timescales on scale-up. This poster focuses on the results of recent residence time and dispersion studies conducted on a pilot plant scale calciner. In the experiments, the influence of operating conditions and material properties on the mean residence time, hold up and axial dispersion in a pilot plant rotary calciner. It was observed that increasing the feed rate did not significantly affect the mean residence time, while increasing the calciner incline and rotary speed decreased mean residence time.
Jacob D. Massa - "Ethane and Methane Dehydrogenation over Pt and PtSn Alloys"
The effect of platinum tin alloy structure and composition on the kinetics and thermodynamics of dehydrogenation and coke formation pathways during light alkane dehydrogenation have been studied using density functional theory. Ethylene is in high demand as a valuable chemical precursor and is among the most produced organic compounds worldwide. Ethane is a cheap, abundant chemical, but has less practical value. Therefore, studying catalysts for ethane dehydrogenation to its corresponding olefin is relevant to modern demands and greatly increases the value of this particular alkane. Supported Pt catalysts are known to be active for ethane dehydrogenation, but the high temperatures required by these endothermic reactions leads to significant coke formation and deactivation. Alloying Pt with Sn and other main group elements has been shown to decrease the amount of coke formed and lead to more stable catalysts. We apply periodic density functional theory to compare the potential energy surfaces from ethane and methane dehydrogenation. This will allow us to better appreciate the effect of catalyst composition (e.g. Pt/Sn ratio) and surface geometry on both reaction energetics and coke formation. As compared to pure Pt, C-H bond scission is more difficult on the alloys, and dihydrogen desorption is more facile.