UNIVERSITY OF MASSACHUSETTS
Grant: $1,998,601 - National Science Foundation - Jul. 30, 2009
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Award Description: This program has two parts 1. Conversion of biomass-derived feedstocks and derivatives to fuels Catalytic fast pyrolysis CFP is used to convert solid biomass into gasoline-range aromatics in a single-step process. CFP begins with the pyrolysis of the solid biomass into smaller oxygenates. These species then enter into the zeolite pores, undergoing a series of dehydration decarbonylation and oligomerization reactions to form aromatics, CO, CO2 and water. The chemistry invloves multiple phases including solid biomass pyrolysis, homogeneous gas-phase reactions and reactions in a zeolite catalyst. In order to optimize the process, the fundamnetal science is being investigated to determine how reaction conditions and catalyst choice influence the distribution and yield of the resulting biofuels and bioproducts. Obtaining such an understanding is extremely challenging because the multi-component nature of this complex system. A range of zeolite catalysts will be prepared covering various pore topologies, acidities, basicities, and other functionalities including those containing metal atoms and ions. Single functional and bi-functional zeolites will also be prepared for testing. The product distributions are correlated with the chemical/catalytic properties of the various zeolite catalysts, for comparison with molecular modeling. Ex situ and in situ spectroscopy are used to characterize the catalysts as-made, and under reaction conditions, to determine how such rapid heating influences the structures and chemical properties of zeolites. These spectroscopies will also be applied to understand the reactive intermediates in gas-phase and zeolite-catalyzed reactions. Electronic structure and kinetic calculations are used to determine the gas phase and zeolite-catalyzed reaction rates. In addition hybrid DFT/forcefield methods are used to compute reaction barriers and frequencies, which will go into micro-kinetic models of reaction networks in both gas-phase and zeolite-catalyzed processes. These results will be validated by the spectroscopic studies and guide process studies of biomass conversion. Various process conditions and catalysts will be investigated including flow (e.g., fluidized bed) and quasi-batch systems. We will study the effects of heating rates and carrier gases on product distributions. Product distributions will be compared with predictions of macroscopic reactor models, which will incorporate inputs from the molecular modeling studies described above. 2. Selective conversion of biomass model systems to chemicals Examination of the role of connectivity, channel size and shape in zeolitic materials developed in the EFRC for dehydration and oxidation of C3 polyfunctional monomers for the synthesis of chemicals. In orde to determine elementary-steps and kinetics of dehydration and oxidation chemistries over zeolite catalysts. Initially this study focuses on the chemical conversion of glycerol, lactic acid and 3-hydroxypropionic acid on a series of multidimensional zeolite materials with different pore sizes to enable us to describe the host-related environments relevant for the protection/de-protection of hydroxyl and carboxyl chemical functionalities in a polyfunctional molecule. Catalyst evaluation and kinetic analysis of primary and secondary reaction pathways will be carried out using microreactor systems capable of online sampling of reactor effluents using concurrent chromatographic and mass spectrometric analysis. The identity and reversibility of relevant elementary steps will be probed using in-situinfrared spectroscopy and chemical and isotopic transient techniques. In conjunction with these experimental studies, computational studies will be conducted with embedded-cluster type calculations that enable a quantum mechanical description of a representative zeolite cluster and account for long-range forces due to the extended structure.
Project Description: The Huber research group is working to study the fundamentals of CFP technology and help move it from the laboratory to an industrial level. We have made significant progress in the project to date. Three papers ave been published on this topic, with another one currently submitted, and are working on several other papers. Our first paper on this topic helped show the importance of heating rate on minimizing coke formation as well as showed that this is a shape selective reaction[9]. Using isotopically labeled compounds we have shown that this reaction follows a hydrocarbon pool mechanism where the carbon and hydrogen are randomly mixed inside zeolite catalysts[10]. In a recently submitted paper we have identified there are both homogeneous and heterogeneous reactions and using FTIR have identified that the pyrolysis step is rapid compared to the heterogeneous step. We are also studying the catalytic properties that help make a good catalyst. We have shown (in a yet to be submitted manuscript) that the aromatic selectivity is a function of the pore size of the zeolite. We have designed a fluidized bed reactor where we have performed CFP with sawdust as a feedstock. Working with collaborators Profs T.J. Mountzarias, Jeff Davis, and Steve de Bruyn Kops, we are developing a computational fluid dynamic model for CFP in a fluidized bed reactor. We are also working with Professor Scott Auerbach to understand the fundamentals of the catalytic chemistry by combining theoretical calculations with experimental results. Working with Prof Raul Lobo, we are working on developing new generations of zeolite catalysts that can be used for CFP technology. We also have a patent application on CFP technology and UMass has licensed CFP technology to the start up company Anellotech. Using this combination of fundamental and applied studies we hope to move CFP technology from the laboratory to a commercial scale reactor.
Jobs Summary: N/A (Total jobs reported: 0)
Project Status: Less Than 50% Completed
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