Dissertation
CATALYTIC WET OXIDATION OF ORGANIC RICH AQUEOUS FRACTION DERIVED FROM BIOMASS THERMOCHEMICAL PROCESSING WITH NOVEL CHAR CATALYSTS IN MICROSCALE BASED REACTORS
Washington State University
Doctor of Philosophy (PhD), Washington State University
01/2022
DOI:
https://doi.org/10.7273/000004356
Handle:
https://hdl.handle.net/2376/124934
Abstract
Development of alternative fuel refineries, in order to improve global sustainability through increased biofuel production, has been increasingly supported by both government and private companies. Thermochemical processes such as hydrothermal liquefaction (HTL) and pyrolysis are leading technologies in this area. However, characterization, treatment, and reuse of aqueous by-products produced by such processes have received little attention. This dissertation is focused on aqueous phase characterization and catalytic advanced oxidation processing in novel microscale reactors. Novel char catalysts and improved process design were developed for efficient removal of organic contaminants. Small acids, cyclic pentenes, and carboxylic compounds such as phenol were initially identified. Model compounds were chosen based on these findings, and catalytic wet oxidation (CWO) processes in batch reactors conducted, in order to obtain reaction rate kinetics. The mechanism of compound oxidation was developed and shown through DFT analysis to be a production of hydroxyl free radicals ( ) in the presence of an oxidant and the N-doped char catalyst. The free radicals readily react with the dissolved organic compound, which was further confirmed with a FeO-N-doped char catalysts in a modified Fenton-like reaction system. In order to better develop a treatment processes which could integrate with a biorefinery, all process engineering experiments were conducted in a continuous solid-catalyzed microscale-based reactor utilizing the FeO-N-doped char catalyst. Time scale analysis was used for reactor geometry optimization in an effort to reduce diffusion time. The design led to a parallel plate reactor with channel depth of 500 microns. Thermochemical aqueous phases produced by pilot scale processes were characterized in detailed by extensive analytical methods. Traditional methods of spectroscopic analysis were limited in the ability to identify more complex oligomeric compounds and thus newer methods such as ICR-MS were utilized. The aqueous phases were successfully treated by the novel catalyst in the microreactor with removal of over 70% total organic carbon present at atmospheric pressure and at 90 °C. Some aqueous phase samples were more complex in nature however, successful decontamination was achieved. Catalytic wet oxidation processing in microscale-based reactors proves to be a plausible treatment option for process water in biorefineries.
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Details
- Title
- CATALYTIC WET OXIDATION OF ORGANIC RICH AQUEOUS FRACTION DERIVED FROM BIOMASS THERMOCHEMICAL PROCESSING WITH NOVEL CHAR CATALYSTS IN MICROSCALE BASED REACTORS
- Creators
- Iva Tews
- Contributors
- Manuel Garcia-Perez (Advisor)Claudio Stockle (Committee Member)Su Ha (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Publisher
- Washington State University
- Number of pages
- 277
- Identifiers
- 99900883035601842
- Language
- English
- Resource Type
- Dissertation