(460c) Geographical Optimization Of Algae Growth In Photobioreactors By Combining CFD Simulations With LIGHT and LIGHT-Temperature Models

Algae present a source of biomass that avoids several problems for other biomass sources.   It does not need to be grown on land used for food crops, and can grow using low quality brackish or salt water.  It also produces a much larger amount of oil per acre than several other alternative biomass sources.  In this study, we simulate the growth of algae over the world to determine which regions would allow the greatest amount of algae production for a packed photobioreactor.  To accomplish this, the starting point was a CFD simulation of a packed bubble column that maximized algae production as a function of flow and geometry parameters.  Then, the concentration field of algae was calculated by integrating several light and light/temperature models of algae growth.  This process was repeated for several latitude/longitude positions on the Earth.  By using this method on a sufficiently small grid with a small timestep, only a set of algebraic equations must be solved to obtain the total algae production, rather than the full set of transport equations. We compare several different light-based and light and temperature-based growth kinetic models to determine monthly algae production.  Our findings indicate that temperature has a significant impact on regional algae growth which cannot be seen using light intensity models alone.  The combination of the light and light/temperature models provides a clearer picture of the global regions favorable for algae production that would not otherwise be captured.  The results of our modeling indicate that the best regions for algae growth with the packed column are the Eastern Caribbean islands, Uganda, and Northeastern Australia.