Dissertation
WET OXIDATION OF SOFTWOOD FOR THE PRODUCTION OF PRECURSORS FOR RENEWABLE FUELS AND CHEMICALS
Doctor of Philosophy (PhD), Washington State University
01/2013
Handle:
https://hdl.handle.net/2376/111948
Abstract
The objective of the proposed research is to find conditions whereby high concentrations of sugars as well as less condensed lignin compounds can be produced by wet oxidation of softwood. Two of the four studies were focused on the determination of wet oxidation process parameters of temperature, oxygen, and residence time in a 10 kg pretreatment system. Wet oxidation showed a high sugar yield of over 300 g/L (glucose, xylose, arabinose, galactose and mannose) with minimum concentrations of sugar degradation products (HMF and furfural) at experimentally determined process conditions. A strategy was then formulated to understand the effect of wet oxidation on the lignin fraction.
In the third study, lignin was extracted from the raw, pretreated and enzymatically treated loblolly pine fractions and analyzed using one-dimensional and two-dimensional Nuclear Magnetic Resonance, NMR techniques. It was hypothesized that during the wet oxidation process, lignin undergoes unique structural transformation via a critical path of in situ methoxylation whereby S-like structures were generated from H-like or G-like structures within the lignin of pretreated loblolly pine. In the fourth study, the lignin potential for the production of phenolic compounds or intermediates was evaluated. Biorefinery lignin was washed and dried to remove the residual sugars and wet oxidation was carried out at the 1-L scale using higher severities i.e. higher temperatures and residence times. Several high value products were identified in the hydrolysate using GC/MS providing a potential for utilization of lignin for chemicals production instead of combined heat and power generation by burning the lignin in boilers.
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Details
- Title
- WET OXIDATION OF SOFTWOOD FOR THE PRODUCTION OF PRECURSORS FOR RENEWABLE FUELS AND CHEMICALS
- Creators
- Diwakar Rana
- Contributors
- Birgitte K Ahring (Advisor)Xiao Zhang (Committee Member)Manuel Garcia (Committee Member)Rick Orth (Committee Member)
- Awarding Institution
- Washington State University
- Academic Unit
- Chemical Engineering and Bioengineering, School of
- Theses and Dissertations
- Doctor of Philosophy (PhD), Washington State University
- Number of pages
- 228
- Identifiers
- 99900581447001842
- Language
- English
- Resource Type
- Dissertation