A multi-objective mixed integer linear programming model proposed to optimize a supply chain network for microalgae-based biofuels and co-products: a case study in Iran.

Abstract

Recently, with efficient methods of cultivating microalgae at hand, researchers and investors have paid considerable attention to the production of different environmentally friendly biofuel products. In this study, a two-stage deterministic model is proposed to design a microalgae-based biofuel and co-product supply chain network (MBCSCN). In the first stage, appropriate locations to cultivate microalgae are identified through the analytical hierarchy process (AHP). In the second stage, a deterministic mathematical mixed integer linear programming (MILP) model is developed for a period of 5 years based on economic and environmental impacts as two criteria. The economic objective function maximizes the overall profit, while the objective function of the environmental impacts seeks to minimize fossil fuel consumption throughout the supply chain. Then, a multi-objective MILP optimization problem is solved using the ε-constraint method. The proposed model is evaluated through a case study in Iran. It has helped to identify appropriate locations for the cultivation of microalgae and to specify the required quantity of feedstock, the species of microalgae, the required technology, and the transportation modes in each step of the supply chain.