A novel superstructure is developed for the biochemical conversion of macroalgae to mixed alcohols (MAs). Microalgae production processes as well as wastewater treatment networks are integrated into the process synthesis framework to improve the environmental performance of the MAs manufacturing process. Based on the superstructure, techno-economic mixed integer linear programming model was formulated. The objective function was the maximization of the net present value (NPV). The results indicated that biofuel production from macroalgae is economically viable, at minimum ethanol selling price (MESP) of $1.26 $/gal. Furthermore, the optimal design has achieved a 90% reduction in CO2 emissions (CE). Sensitivity analysis indicated that the selling price of heavier alcohols and purchasing price of macroalgae are the most sensitive parameters to MESP.
Keywords Superstructure optimization, process synthesis, macroalgae, biofuels, mixed alcohols