Abstract
This thesis addresses the maritime sector’s substantial climate and environmental impacts by exploring and optimizing a novel lignin-alcohol fuel technology called Cold-processed Lignin in Ethanol Oil (CLEO). The research investigates various aspects of CLEO, including the physiochemical characterization of highly concentrated lignin dispersions, production optimization, the development of novel lignin size determination methodologies, and pathways towards an industrial implementation of CLEO.
Key findings include the identification of a stable lignin-aggregate network that prevents lignin precipitation at above 30 wt% lignin concentrations. Production yields improved from 42% to 89% through enhancements in solvent composition with glycerol and modifications of process parameters, achieving immediate stability and avoiding the most energy-demanding processing step. A central aspect of CLEO production is alcohol dispersibility, which was found to correlate with lignin molecular size. This work presents a novel method for lignin size measurement based on Taylor Dispersion Analysis (TDA), which effectively and reproducibly measures the hydrodynamic volume of lignin molecules, correlating it to molecular weight through polystyrene calibration. Additionally, exploring minor modifications to the hydrothermal pretreatment of wheat straw significantly improved the alcohol dispersibility of residual lignin, presenting a pathway towards large-scale integration of CLEO technology into existing bioprocessing industries.
The collective work in this thesis demonstrates the potential of using lignin-alcohol dispersions as a viable marine fuel while improving the understanding of solvent-lignin interactions in these dispersions.
Key findings include the identification of a stable lignin-aggregate network that prevents lignin precipitation at above 30 wt% lignin concentrations. Production yields improved from 42% to 89% through enhancements in solvent composition with glycerol and modifications of process parameters, achieving immediate stability and avoiding the most energy-demanding processing step. A central aspect of CLEO production is alcohol dispersibility, which was found to correlate with lignin molecular size. This work presents a novel method for lignin size measurement based on Taylor Dispersion Analysis (TDA), which effectively and reproducibly measures the hydrodynamic volume of lignin molecules, correlating it to molecular weight through polystyrene calibration. Additionally, exploring minor modifications to the hydrothermal pretreatment of wheat straw significantly improved the alcohol dispersibility of residual lignin, presenting a pathway towards large-scale integration of CLEO technology into existing bioprocessing industries.
The collective work in this thesis demonstrates the potential of using lignin-alcohol dispersions as a viable marine fuel while improving the understanding of solvent-lignin interactions in these dispersions.
Original language | English |
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Publisher | Department of Geosciences and Natural Resource Management, Faculty of Science, University of Copenhagen |
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Number of pages | 246 |
Publication status | Published - 2024 |