Thesis
Continuous sequential hydrothermal liquefaction process for bio-oil production & nutrient recovery from wet microalgae biomass
Washington State University
Master of Science (MS), Washington State University
05/2016
Handle:
https://hdl.handle.net/2376/102437
Abstract
Hydrothermal Liquefaction has been successfully demonstrated for producing a fuel from different microalgae. However, most of these studies have been limited to batch reactor testing, wherein lie a great deal of uncertainties concerning the kinetics, heating and cooling rates, effect of reactor designs, and organic solvent use for product partitioning. Furthermore, the high temperatures used significantly decreased the potential to recover nutrients and develop value-added byproducts. Therefore, the development of a continuous-flow operating system that can be easily built, scaled-up, allows co-product retrieval and does not involve the use of organic solvents, is critical for the advancement and sustainable commercialization of microalgae-derived biofuels. Sequential hydrothermal liquefaction trials with several microalgae were performed in order to determine strain-specific process metrics, thermophysical properties, and engineering data, for the design and development of a continuous-flow reactor system. The Chlorella sp. exhibited preeminence with biocrude yields ranging between 30 - 32 wt%, and phosphorous recovery percentages exceeding 85%. Contrastingly, one Galdieria sulphuraria strain had substantial C and P loss to the char, approximately 39% and 46% respectively. Nonetheless, such results highlighted the potential of reusing the water product effluents to increase mixotrophic productivity, or to attain value added products through fermentation or anaerobic digestion. The biocrudes produced had oxygen contents of 7 - 14%, nitrogen of 5 - 8%, very low sulfur (< 1.4%), and higher heating values between 33 - 37 MJ/kg. Additionally, it was determined that the biochar residue could be used as a low-quality fuel to supply part of the heat energy (6 - 30 MJ/kg). Based on corresponding mass and energy balances, the continuous-flow prototype was sized and developed for a nominal capacity of 2 L-hr-1 and SS 316L construction. The system includes the successive sub-critical water extraction and liquefaction reaction stages, as well as the design of two novel non-solvent product separation steps. With the prototype system, an initial exploratory continuous-flow performance assessment of sequential hydrothermal liquefaction for biocrude production and nutrient recovery from different microalgae samples can be developed. Fundamental data may be collected, that may be further utilized to survey additional optimization possibilities.
Metrics
Details
- Title
- Continuous sequential hydrothermal liquefaction process for bio-oil production & nutrient recovery from wet microalgae biomass
- Creators
- Jose Salomon Martinez Fernandez
- Contributors
- Shulin Chen (Chair)Manuel Garcia-Perez (Committee Member) - Washington State University, Biological Systems Engineering, Department ofSu Ha (Committee Member) - Washington State University, Chemical Engineering and Bioengineering, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Biological Systems Engineering, Department of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 129
- Identifiers
- 99900525201001842
- Language
- English
- Resource Type
- Thesis