Time: 14 July, 03:00 pm
Venue：Conference Room on the First Floor, Energy Building1#
Carsten Sievers
Georgia Institute of Technology
Biography：
Carsten Sievers obtained his Diplom and Dr. rer nat. degrees in Technical Chemistry at the Technical University of Munich, Germany. Under the guidance of Prof. Johannes A. Lercher, he worked on heterogeneous catalysts for various processes in petroleum refining including hydrogenation of aromatics in Diesel fuel, alkylation, alkane activation, and catalytic cracking. Additional research projects included novel catalytic system, such as supported ionic liquids. In 2007, he moved to the Georgia Institute of Technology to work with Profs. Christopher W. Jones and Pradeep K. Agrawal as a postdoctoral fellow. His primary focus was the development of catalytic processes for biomass depolymerization and synthesis of biofuels. He joined the faculty at the Georgia Institute of Technology in 2009. His research group is developing catalytic processes for the sustainable production of fuels and chemicals. Specific foci are on the stability and reactivity of solid catalysts in aqueous phase, surface chemistry of oxygenates in water, production of specific chemicals from biomass, applied spectroscopy, synthesis of well-defined catalysts, methane conversion, mechanocatalysis, CO2 capture, pyrolysis, and gasification. He is Director of the Southeastern Catalysis Society, Director of the ACS Division of Catalysis Science & Technology and the AIChE Division of Catalysis and Reaction Engineering, and Editor of Applied Catalysis A: General.
Abstract:
The conversion of biomass to value-added chemicals and fuels is one of the great challenges in modern chemical engineering. Since biomass contains much more oxygen than most chemicals and fuels, it is critical to develop processes for removing oxygen containing functional groups. Catalysts will play a critical role in most of these processes because they are critical for providing the required selectivity to certain products. Specific reactions for oxygen removal include hydrodeoxygenation (HDO), dehydration, condensation, and ketonization. The development of efficient catalysts for these reactions will require a good understanding of the interactions of biomass-derived oxygenates with potential catalysts. Our work aims to provide this insight using in-situ spectroscopy.
Selective dehydration can be used to produce specific chemicals from biorenewable feedstocks. The dehydration of glycerol to acrolein is a particularly promising process because large amounts of glycerol are produced as a by-product of bio-diesel. In this talk, dehydration of glycerol over niobia catalysts with different concentrations of Br?nsted and Lewis acid sites will be described. Important surface species are identified by in-situ IR spectroscopy, and it is shown how different acid sites affect different dehydration paths and the formation of coke.
In a separate study, we use time-resolved operando IR spectroscopy to elucidate the reaction paths of aromatic oxygenates during HDO over H-BEA and Pt/H-BEA zeolites. Trends in reactivity and selectivity are explained based on nature of surface species formed from different oxygenates. It is also shown that carbonaceous deposits can undergo several stages of aging before significant deactivation is observed. Most importantly, oxygenates with two functional groups can form strongly bound surface species that prevent diffusion of reactants and products. The new insight will allow for developing protocols for efficient regeneration of spent HDO catalysts.
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