PRIMARY AND SECONDARY REACTIONS  OF CELLULOSE MELT PYROLYSIS

Paulsen, Alex D

Publication:
PRIMARY AND SECONDARY REACTIONS OF CELLULOSE MELT PYROLYSIS

dc.contributor.advisor	Paul J. Dauenhauer
dc.contributor.author	Paulsen, Alex D
dc.contributor.department	University of Massachusetts Amherst
dc.date	2024-03-27 18:23:17
dc.date.accessioned	2024-04-26T15:47:25Z
dc.date.available	2024-04-26T15:47:25Z
dc.date.issued	2014
dc.date.submitted	February
dc.date.submitted	2014
dc.description.abstract	Fast pyrolysis of biomass is a next-generation biofuels production process that is capable of converting solid lignocellulosic materials (in their raw form) to a transportable liquid (bio-oil) which can be catalytically hydrogenated to fuels and chemicals. Pyrolysis reactors depolymerize solid biomass by heating the feedstock (in the absence of oxygen) up to high temperatures (400 – 600 °C) to produce a short-lived intermediate liquid phase (only a few seconds), which ultimately breaks down to form small (1-6 carbon) oxygenates. These vapor-products can then be condensed at room temperature to produce liquid bio-oil. While biomass fast pyrolysis has enormous potential to produce renewable fuels, an understanding of the fundamental chemistry and transport processes of biomass pyrolysis to produce bio-oil is not available in the literature. This work utilizes co-pyrolysis and isotopic labeling to study the liquid-phase secondary reactions of levoglucosan to form anhydrosugars, pyrans, and light oxygenates. Isotopic labeling studies also reveal that hydrogen exchange is a critical component of levoglucosan deoxygenation. Next, the effects of pyrolysis reaction temperature and sample length scale are discussed. These studies revealed that the yield of total furan rings (i.e., all products containing a five-membered furan ring) does not change significantly with increased reaction temperature compared to other pyrolysis products, such as light oxygenates and anhydrosugars. However, the functional groups bound to the furan ring (e.g., alcohols and aldehydes) are easily cleaved to produce smaller furans. This chemistry was targeted by impregnating cellulose with palladium on carbon to selectively decarbonylate oxygenated furans within liquid intermediate cellulose to form deoxygenated furans resulting in a more stable bio-oil. The last part of this thesis, a new experimental technique, Spatiotemporally-Resolved Diffuse Reflectance in situ Spectroscopy of Particles (STR-DRiSP), which is capable of measuring biomass composition during fast pyrolysis with high spatial (ten micron) and temporal (one millisecond) resolution is developed. Compositional data were compared with a comprehensive two-dimensional single particle model. The STR-DRiSP technique can be used to determine the transport-limited kinetic parameters of biomass decomposition for a wide variety of biomass feedstocks.
dc.description.degree	Doctor of Philosophy (PhD)
dc.description.department	Chemical Engineering
dc.identifier.doi	https://doi.org/10.7275/6044711.0
dc.identifier.orcid	N/A
dc.identifier.uri	https://hdl.handle.net/20.500.14394/18602
dc.relation.url	https://scholarworks.umass.edu/cgi/viewcontent.cgi?article=1254&context=dissertations_2&unstamped=1
dc.source.status	published
dc.subject	Biomass Pyrolysis
dc.subject	Cellulose
dc.subject	Spectroscopy
dc.subject	Supported Metal Catalysts
dc.subject	Palladium
dc.subject	Levoglucosan
dc.subject	Catalysis and Reaction Engineering
dc.title	PRIMARY AND SECONDARY REACTIONS OF CELLULOSE MELT PYROLYSIS
dc.type	openaccess
dc.type	dissertation
digcom.contributor.author	isAuthorOfPublication\|email:apaulsen@ecs.umass.edu\|institution:University of Massachusetts Amherst\|Paulsen, Alex D
digcom.identifier	dissertations_2/229
digcom.identifier.contextkey	6044711
digcom.identifier.submissionpath	dissertations_2/229
dspace.entity.type	Publication