Dissertation
Biomass-assisted synthesis of hierarchical zeolites for catalytic fast pyrolysis of lignocellulose biomass and waste plastic
Doctor of Philosophy (PhD), Washington State University
01/2019
Handle:
https://hdl.handle.net/2376/110993
Abstract
This study developed a green production platform of renewable biofuel and valuable chemicals through optimization of catalytic pyrolysis and minimization of the related environmental concerns. A new post-synthetic methodology in zeolite modification successfully induced the formation of unique hierarchical HZSM-5 catalyst to further improve its functionality in the catalytic pyrolysis of lignocellulose biomass and waste plastic material. The first step of modification is via controlled alkaline treatment, which tailors mesopore formation while preserving crystallinity and acid properties of HZSM-5 zeolite. In the second step, the effluent from the alkaline treatment was subjected to crystallization condition in the presence of alkaline lignin to induce reassembly of the alkali-treated crystal subunits of HZSM-5. The surface properties of hierarchical HZSM-5 indicated the impact of lignin during the biomass-assisted zeolite synthesis, in which the conventional synthetic surfactant was replaced with natural organic materials. Additionally, the lignin used in catalyst preparation was acquired from the waste stream of an effective alkaline pretreatment of woody biomass in contribution to the valorization of waste by-product in bioenergy production. In the catalytic pyrolysis using the hierarchical HZSM-5 zeolites, high-quality liquid and gas products were obtained with better product yields compared to the parent HZSM-5. The excellent catalytic performances in the hierarchical HZSM-5 were also observed in the effectiveness of reducing coke formation on the catalyst. The secondary structures developed on the surface of HZSM-5 enabled catalytic cracking of bulky oxygenated intermediates and facilitated their accessibility to the active acid sites within the essential microporous zeolite framework for aromatization. Moreover, the larger pore openings and the intercrystalline mesopores in the hierarchical HZSM-5 were able to increase the diffusion flow of the reactants derived from the thermal decomposition of both lignocellulose biomass and plastic material. The optimization of process condition and enhancement of targeted products were further achieved in catalytic co-pyrolysis of lignocellulose biomass and plastic waste. Lastly, thermal degradation behavior of feedstock used in this study, and kinetic study of catalytic co-pyrolysis of lignocellulose and plastic mixture was evaluated with isoconversional methods.
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Details
- Title
- Biomass-assisted synthesis of hierarchical zeolites for catalytic fast pyrolysis of lignocellulose biomass and waste plastic
- Creators
- Moriko Qian
- Contributors
- Hanwu Lei (Advisor)Birgitte K Ahring (Committee Member)Joan Q Wu (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 173
- Identifiers
- 99900581704601842
- Language
- English
- Resource Type
- Dissertation