Otimização de biorrefinarias integradas de cana-de-açúcar e microalgas utilizando programação linear inteira mista

Abstract

As the energy demand continues to grow, the use of fossil fuels has become a global problem. For this reason, the search for sources that are less harmful to the environment is increasing, and biomass, with the production of biofuels, is a promising alternative for preventing global warming. Biomass is considered a carbon-neutral feedstock and its efficient conversion represents an interesting option for the production of energy and value-added chemicals. The process of converting and/or upgrading biomass takes place through the implementation of biorefineries; these facilities represent the starting point for the promotion of bioeconomy models. Therefore, the aim of this study is to develop a mixed integer linear programming (MILP) model based on an integrated biorefinery applied in Colombia for the supply chain, using information from multiple conversion routes to select the optimal combination of processes taking into account economic and environmental aspects. Six types of biorefineries with the potential to produce bioethanol, electricity, bagasse pellets, SNG, green diesel, green gasoline, jet fuel and biochar were considered. Four technologies for the conversion of microalgae grown on vinasse were analysed: biodigestion, supercritical water gasification, hydrothermal liquefaction and hydrothermal carbonisation. The MILP model was solved in Lingo software using a database library of process models. The results show that microalgae are a promising strategy for treating vinasse and that microalgae are more energy efficient than sugarcane in terms of land use. The production of biofuels and electricity using sugarcane as a feedstock has proven to be a promising alternative for energy production from an economic and environmental point of view. The main challenge for the project of integrated biorefineries is to select the best combination of processes and operations taking into account economic aspects, with the location and logistics system being the most impactful in environmental terms.