Investigation of Catalytic Biomass Reactions Through Integrated Computational and Experimental Methods

Johnson, Benjamin

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Year:: 2018
Contributor:: Johnson, Benjamin (creator); Peterson, Andrew (Advisor); Goldsmith, C. Franklin (Reader); Guduru, Pradeep (Reader); Brown University. Engineering: Fluid, Thermal, and Chemical Processes (sponsor)
Genre:: theses
Subject:: Catalysis; Biomass energy; Methanation; DFT; Experimental design
Extent:: 13, 97 p.
DOI: https://doi.org/10.26300/3t6p-qs42

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Abstract:: Liquid biofuels are a carbon-neutral alternative fuel which shares many of the desirable qualities of conventional petroleum, including its high energy content. One process used for biomass conversion is deoxygenation, which converts carboxylic acids and triglycerides, the primary components of vegetable oil, into diesel-like hydrocarbons. To better understand the deoxygenation reaction mechanism, a micro-kinetic model was constructed to simulate the deoxygenation reaction network. Of particular note is the presence of hydrogen in the mechanism, where it can serve both beneficial and detrimental roles. It is required for hydrogenation of certain reaction intermediates, but excess hydrogen can limit the rate of other key steps. The mechanism was also studied through the development of an experimental reaction process for the continuous deoxygenation of palmitic acid. Methanation is another biomass conversion process often used in conjunction with gasification or pyrolysis to make synthetic natural gas from lignocellulosic biomass. This work examines how the activity of methanation catalysts can be greatly influenced by minor changes in electronic structure which can be applied in different ways. Co-adsorbates can exert an influence on catalyst activity, although these are often undesirable and can lead to `poisoning' of the catalyst. Co-adsorbate effects are studied in depth by combining DFT calculations and other mathematical models to quantify the different ways in which co-adsorbates can influence desired reactions. Mechanical strain can also be used to alter catalyst activity, and it was previously proposed based on computational research that applying strain to a nickel catalyst can increase its activity for methanation. This work developed and operated a process for conducting thermochemical methanation over a mechanically strained catalyst. Results surprisingly indicated that mechanical strain decreased the activity of nickel. Additional computational analysis suggests that the application of strain promotes CO-splitting but inhibits hydrogenation, resulting in a net decline in activity. This result shows that catalyst activity can be manipulated through mechanical strain, but that additional challenges remain to fully taking advantage of this property.
Notes:: Thesis (Ph. D.)--Brown University, 2018

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Rights: In Copyright
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Johnson, Benjamin, "Investigation of Catalytic Biomass Reactions Through Integrated Computational and Experimental Methods" (2018). Fluid, Thermal, and Chemical Processes Theses and Dissertations. Brown Digital Repository. Brown University Library. https://doi.org/10.26300/3t6p-qs42

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Fluid, Thermal, and Chemical Processes Theses and Dissertations

Theses and Dissertations for the Fluid, Thermal, and Chemical Processes department.
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