Simulation and Energy Integration for a Biorefinery of Valuable Substances and Biofuel from Microalgae Biomass

Abstract

Traditional biofuels have been criticized, primarily, because there is not neutral CO2 balance and its production is based on raw materials used for human alimentation. Microalgae emerges as a promising renewable, not food, source for biofuels production, however, its principal obstacle are the high production costs. One alternative proposed by researchers to achieve a feasible production is the incorporation of the biorefinery concept, which is a framework for producing several products, including energy, from biomass giving economic competitiveness due to high value co-products. In this paper, a first approximation of a topology of microalgae biorefinery was analyzed. The analysis was based on process simulation with the software SuperPro Designer for modeling the topology through stages. The harvest stage consists of a chemical flocculation and a filter press; the lipid extraction stage was made first lysing the cells by means of acid and basic hydrolysis, then a pigment extraction with hexane, Polyunsaturated Fatty Acids (PUFAs) concentration forming urea complexes, and triglycerides (TGs) recovery from complexes formed; furthermore, the last stage where the transformation from lipids to biodiesel through homogeneous transesterification ocurred. Finally, taking into account the energy integration principle with Aspen Energy Analyzer was possible to reduce the external services of heating and cooling with the aim to improve the topology propoused.