Dissertation
FRACTIONATION OF BIOMASS VIA SEQUENTIAL HYDROTHERMAL LIQUEFACTION TO PRODUCE VALUE-ADDED PRODUCTS AND TECHNO-ECONOMIC ANALYSIS
Doctor of Philosophy (PhD), Washington State University
01/2020
Handle:
https://hdl.handle.net/2376/112267
Abstract
Hydrothermal liquefaction (HTL) is considered to be a promising technology for biomass conversion. The main advantages of HTL include accepting wet feedstock, operating under moderate temperature and pressure conditions, and having high production yield and conversion efficiency. This work consists of both experimental investigations and techno-economic analysis (TEA) of a two-stage sequential hydrothermal liquefaction (SeqHTL) process as an alternative HTL design for treating various types of biomass.
Processing algae was first studied. A critical review on SeqHTL for converting algae was conducted compared to one-stage direct HTL (DHTL). Operating principles, reaction mechanisms, feasibilities, and advantages of SeqHTL for harvesting co-products were discussed. Next, a comparative TEA between SeqHTL and DHTL for algal biofuel production was performed. Results showed that milder operating conditions and the unique capability of co-product production led to reduced capital and operating costs for SeqHTL. A sensitivity analysis revealed that improving the yield of co-products reduced the biofuel cost.
The next study was the HTL treatment of lignocellulose. The first stage of SeqHTL was used to pretreat the biomass at low temperatures to break the cell walls and release sugars. In the second stage, value-added products from sugars and lignin were produced at moderate temperatures. Results showed that SeqHTL achieved higher conversion yields than DHTL due to the pre-extraction of sugars. Various characterization techniques were used to measure the performance differences between SeqHTL and DHTL. Additionally, to overcome the barrier of low sugar recovery in the first stage due to the recalcitrance of the lignocelluloses, a pretreatment method prior to HTL using fungi enhanced with Mn addition was investigated. The pretreatment facilitated thermal decomposition reaction and enabled more sugar recovery.
Finally, a TEA was performed on the extraction of bioactive compounds from potato peels via sequential hydrothermal extraction. This generated merits that provided economic results on the two-stage process.
This work highlighted the fractionation feature of SeqHTL in comparison with DHTL when used to treat various biomasses. The research encompassed process chemistry, kinetics, design, and economics. Findings demonstrated that SeqHTL technology holds promise in processing various feedstocks for bio-chemical production, natural compounds extraction, and waste resources utilization.
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Details
- Title
- FRACTIONATION OF BIOMASS VIA SEQUENTIAL HYDROTHERMAL LIQUEFACTION TO PRODUCE VALUE-ADDED PRODUCTS AND TECHNO-ECONOMIC ANALYSIS
- Creators
- Xiangyu Gu
- Contributors
- Shulin Chen (Advisor)Cornelius F Ivory (Committee Member)Manuel Garcia-Perez (Committee Member)Steven R Saunders (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
- 309
- Identifiers
- 99900581411001842
- Language
- English
- Resource Type
- Dissertation