MICROALGAE CARBON CAPTURE
Microalgae captures carbon dioxide as it grows through photosynthesis. The microalgae can then be harvested and used as a feedstock for various process, including making biochar. Our Microalgae team is working on the design of a floating photobioreactor (PBR), with a focus on mixing, to optimise growth rate of the microalgae. We are working on making and testing a prototype, and investigating filtration and microalgae harvesting.
MICROALGAE INTRODUCTION
Microalgae captures carbon dioxide as it grows through photosynthesis. Our chosen microalgae species, Nannochloropsis Oceanica has carbon concentrating mechanisms, increasing the rate of photosynthesis. This microalgae species lives in the ocean, which presents a unique opportunity to use biological mechanisms for CO2 capture without taking up important terrestrial land.
TESTING OUR DESIGN
We have a CAD model of our FPBR, we simulate the mixing of the microalgae using ANSYS Fluent. We choose to focus on the mixing characteristics as they are the most significant factor within our control for promoting algal growth. We simulate the motion of the FPBR on an ocean surface, and examine the fluid flow within. We can influence the fluid flow characteristics by introducing baffles and internal partitions, and the simulations provide rapid feedback on how our proposed design changes influence the fluid mixing.
We are also building a small scale wave tank so that we can physically test 3D printed prototypes.
FLOATING PHOTOBIOREACTOR DESIGN
We are designing a floating photobioreactor (FPBR) to grow our chosen species of microalgae. The FPBR will be placed in the ocean, which allows us to use the energy of the waves to mix the microalgae. This provides significant energy savings compared to traditional microalgae cultivation. We are working to optimise the shape of the FPBR, and the incorporation of baffles to ensure that the microalgae is efficiently mixed, allowing it access to light and nutrients.
We are designing experiments to determine how we plan to filter the microalgae, to prevent contamination in the PBR and the prevent any contamination of the ocean. We are also determining an energy efficient method to harvest the microalgae for use as a feedstock for biochar. This may include the use of filtering or coagulants to remove the bulk water from the microalgae.