Multiphysics Modeling and Design of River Reactors for the Continuous Production of Saltwater Algae and Carbon Dioxide Sequestration
Open Access
- Author:
- Bell, Lindsey
- Graduate Program:
- Agricultural and Biological Engineering
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 19, 2025
- Committee Members:
- Howard M Salis, Thesis Advisor/Co-Advisor
Ali Borhan, Committee Member
Suat Irmak, Program Head/Chair
Juliana Vasco-Correa, Committee Member - Keywords:
- algae
carbon sequestration
biofuel
finite element method
bioreactor
sustainability - Abstract:
- Microalgae are rapidly gaining traction as a sustainable feedstock for biofuels; however, the use of microalgae as a feedstock is currently limited by cost barriers, low efficiency, and a lack of commercial scale production operations. In lieu of these commercial systems, physical models are used to estimate the magnitude of algae production on a large scale. However, current open system models are flawed in that they do not often account for fluctuations in medium composition (e.g., ocean water composition), climate, or spatial variations in the distribution of nutrients. Thus, the objective of this research is to construct an open system model that accounts for variations in environmental parameters and the spatial distribution of nutrients, and to use this model to optimize the design of a novel open, continuous system for microalgae production according to the average continuous productivity of algal biomass. An optimization procedure tests the productivity of the reactor under a variety of scenarios according to carbon dioxide delivery method: inlet addition of carbon dioxide or the delivery of carbon dioxide through absorption columns dispersed across the length of the reactor. Compared to an unsupplemented system, a system with carbon dioxide delivery has a higher average continuous productivity, and the continuous delivery of carbon dioxide via dispersed absorption columns best compensates for carbon dioxide loss across the length of the reactor. As such, the success of microalgae cultivation depends on technological improvements in carbon capture and carbon delivery methods. Nevertheless, despite the necessity of a carbon delivery system, the cost efficiency of an open, continuous system will be superior to that of closed or batch cultivation systems. Thus, such a system may allow microalgae-based biofuel to become cost-competitive with petroleum based fuels.