CIGR XVII th World Congress – Québec City, Canada – June 13-17, 2010 1 XVII th World Congress of the International Commission of Agricultural and Biosystems Engineering (CIGR) Hosted by the Canadian Society for Bioengineering (CSBE/SCGAB) Québec City, Canada June 13-17, 2010 NUMERICAL INVESTIGATION OF A BUBBLE-COLUMN PHOTO- BIOREACTOR DESIGN FOR BIODIESEL PRODUCTION FROM MICROALGAE I.-H. SEO, I.-B. LEE 1 J.-S. CHOI, S.-H. SONG , H.-S. HWANG, S.-W. HONG, J.P. BITOG, K.-S. KWON, 1 Department of Rural Systems Engineering and Research Institute for Agriculture and Life Sciences, College of Agricultural and Life Sciences, Seoul National University, Korea, iblee@snu.ac.kr CSBE100880 – Presented at Section IV: Rural Electricity and Alternative Energy Sources Conference ABSTRACT Renewable energy is interesting as a countermeasure for the fossil energy depletion and carbon dioxide reduction. Biodiesel using vegetable oils is one of the most desirable renewable energy because it can be an alternate diesel to petroleum. However, the biodiesel from soybean or corn, etc. can be confronted with food crisis. Microalgae have recently been researched as a new biodiesel source which not only contain high oil lipids with high growth rate but also offer value-added products such as cosmetics, health functional food or pharmacy from the residue. Because pond production system has limitations in unstable weather conditions and insufficient land availability especially in Korea, photo-bioreactors (PBRs) is essential for their cultivation. More so, controlling the suitable environments such as light, nutrients, carbon dioxide, temperature, etc. in the PBR is possible. Despite the availability of PBRs at present, only a few can be practically used for mass production due to some limitations. In this study, computational fluid dynamics (CFD) was used to design an optimum bubble-column PBR for mass production of microalgae. Multi-phase models including bubble movement, meshes and time step independent tests were considered to develop the three-dimensional CFD model. The model was enhanced and validated through Particle Image Velocimetry (PIV) tests. Various types of PBRs were simulated and compared quantitatively with consideration of the microalgae’s growth model adaptable for the CFD model and an evaluation method of mixing efficiency in the PBRs has been done. This research can be used as a basic technique for microalgae production on a large scale. Keywords: Bio-diesel, computational fluid dynamics (CFD), microalgae, photo- bioreactor INTRODUCTION Climate change and exhausting of petroleum have been a global problem. Renewable and carbon neutral energy source are necessary for environment and economic sustainability. Natural energy from solar, wind and biomass are now being watched with keen interest to solve the problem. Among the mentioned energy sources, biodiesel derived from biomass and oil crops is a potential renewable and carbon neutral alternative