Design and analysis of biodiesel production from algae grown through carbon sequestration

This paper addresses the design and techno-economic analysis of an integrated system for the production of biodiesel from algal oil produced via the sequestration of carbon dioxide from the flue gas of a power plant. The proposed system provides an efficient way to the reduction in greenhouse gas emissions and yields algae as a potential alternative to edible oils currently used for biodiesel production. Algae can be processed into algal oil by various pathways. The algal oil can then be used to produce biodiesel. A flowsheet of the integrated system is synthesized. Then, process simulation using ASPEN Plus is carried out to model a two-stage alkali catalyzed transesterification reaction for converting microalgal oil of Chlorella species to biodiesel. Cost estimation is carried out with the aid of ICARUS software. Further economic analysis is performed to determine profitability of the algal oil to biodiesel process. The results suggest that, for the algal oil to biodiesel process analyzed in this study, factors such as choosing the right algal species, using the appropriate pathway for converting algae to algal oil, selling the resulting biodiesel and glycerol at a favorable market selling prices, and attaining high levels of process integration can collectively render algal oil to be a competitive alternative to food-based plant oils.