Chemical and Biomedical Engineering - Research Publications
Permanent URI for this collection
Search Results
1 - 4 of 4
-
ItemEnhanced CO2 bio-utilization with a liquid-liquid membrane contactor in a bench-scale microalgae raceway pond(Elsevier Ltd, 2019-12-01)Microalgae are able to absorb CO2 generated from sources such as flue gas to produce biomass with high lipid content. In this research, an immersed liquid-liquid membrane contactor was investigated to deliver CO2 captured by a chemical solvent to the microalgae culture via semipermeable membranes. Experiments showed that the CO2 mass transfer could be facilitated by using a thinner membrane support layer, or avoiding a support altogether, as the support was liquid filled which reduced the mass transfer coefficient. In order to better condition the culture media, the solvent flow was controlled by pH feedback. This scenario showed comparable biomass productivity (0.10 g L-1 d-1) to the conventional direct bubbling method, but with a lower energy cost and higher CO2 utilization efficiency. Further, a pond liner was formed from flat sheet membranes as a more effective alternative to a hollow fiber arrangement. The optimized system achieved a CO2 utilization efficiency of up to 90% compared to 47% with the uncontrolled hollow fiber membrane system and 11% for air sparging, thereby reducing the CO2 released to the atmosphere.
-
ItemCritical review of strategies for CO2 delivery to large-scale microalgae cultures(CHEMICAL INDUSTRY PRESS, 2018-11-01)Microalgae have great, yet relatively untapped potential as a highly productive crop for the production of animal and aquaculture feed, biofuels, and nutraceutical products. Compared to conventional terrestrial crops they have a very fast growth rate and can be produced on non-arable land. During microalgae cultivation, carbon dioxide (CO2) is supplied as the carbon source for photosynthesising microalgae. There are a number of potential CO2 supplies including air, flue gas and purified CO2. In addition, several strategies have been applied to the delivery of CO2 to microalgae production systems, including directly bubbling CO2-rich gas, microbubbles, porous membrane spargers and non-porous membrane contactors. This article provides a comparative analysis of the different CO2 supply and delivery strategies and how they relate to each other.
-
ItemThe effects of medium salinity on the delivery of carbon dioxide to microalgae from capture solvents using a polymeric membrane system(SPRINGER, 2019-06-01)Efficient provision of carbon dioxide to microalgae is one of the major challenges to cost-effective large-scale cultivation. Previously, we have demonstrated the effectiveness of a novel membrane system in delivering CO2 to a marine strain of Chlorella sp. from CO2-loaded solvents. In this approach, the solvent is pumped through a non-porous hollow fibre membrane immersed in a microalgae medium, allowing passive transfer of CO2 that is utilised by the microalgae to enhance their growth, while simultaneously regenerating the solvent. In this article, we compare the growth of both fresh water and marine strains of algae using this membrane delivery system. While the fresh water medium has less pH buffering capacity and can dissolve less CO2, it proves similarly effective in delivering CO2 to the growing algae. Both the freshwater and marine species of Chlorella have slightly higher growth rates than the other species tested—Dunaliella tertiolecta and Haematococcus pluvialis. However, due to the lower osmotic pressure of the fresh water medium, more water is drawn through the membrane into the solvent than when the salt water medium is used. In conclusion, while CO2 delivery through the membrane system is effective for both salt and fresh water media, better performance is obtained for the salt water medium.
-
ItemThe use of monoethanolamine and potassium glycinate solvents for CO2 delivery to microalgae through a polymeric membrane system(ELSEVIER SCIENCE BV, 2017-12-15)