Modeling and Dynamic Optimization of Microalgae Cultivation in Outdoor Open Ponds

Abstract

Compared to other oil crops, microalgae can achieve much higher oil yields and CO2 fixation rates making algal biomass a potential feedstock for the production of ecofriendly renewable biofuels. However, the production cost remains too high for commodity markets such as transportation fuels. An optimization formulation is proposed for the cultivation of microalgae in outdoor open ponds. Operations including dilution rate, and CO2 gas feed rate are optimized to minimize the cost of producing algal biomass in an annual production cycle. Moreover, the economic advantage of utilizing waste CO2, e.g. industrial flue gases, in providing CO2 for algal growth is evaluated. Utilization of waste heat recovery in heating up the open pond culture to improve cultivation during cold weather is analyzed as well. Also, a supply chain model is proposed and optimized to determine the optimal location of an algae facility coupled with municipal wastewater treatment for the purpose of utilizing wastewater nutrients.