Multi-objective optimization of the supply chain of biofuels from residues of the tequila industry in Mexico

The tequila industry in Mexico generates large amounts of lignocellulosic residues from the cultivation fields as well as from the tequila processing industries. Nowadays, these residues are disposed, but they could be used as feedstock for a biorefinery. Before implementing a biorefinery system to treat the residues from the tequila industry in Mexico, it is necessary to assess the economic and environmental performance of the entire supply chain for biofuel production. Developing a proper optimization framework for supply chain management in the tequila industry in Mexico that will consider all the activities involved along with the conflicting objectives of its daily operation represents a scientific challenge. Therefore, this paper presents a multi-objective optimization approach for designing such a supply chain that accounts for the simultaneous maximization of the net present value and environmental performance of the network. The environmental objective function accounts for impacts in ecosystem quality, human health and damage to resources. These are quantified through the eco-indicator 99 method. Numerical results show that the implementation of a biorefinery system in Mexico based on the residues from the tequila industry can provide significant economic and environmental benefits. Particularly, results indicate that the best economic solution shows a profit of 7.9 × 108 USD/year. Furthermore, the distributed system involving several central and distributed processing plants allows obtaining significant economic improvements. Finally, the results reported through Pareto curves allow identifying several solutions that are appealing for decision makers.