Multi-objective optimization of an industrial ethanol distillation system for vinasse reduction – A case study

The fluctuation in the price of oil and the positive consequences of fuels from renewable sources (compared to fossil fuels) propel the expansion of biofuel global production. In this work, the current distillation operation of an ethanol distillery is simulated and compared to the use of indirect heating, evaluating the environmental and economic impacts associated with vinasse fertirrigation by using an external automated tool. Results show that the replacement proposed decreases approximately 15% of the amount of vinasse. Moreover, as the modifications do not change the outlet flowrates, such revamping might be done without additional operational changes that could affect the productivity. The environmental evaluation presents positive results, showing that the new configuration may decrease all environmental impacts categories assessed. From an economic perspective, the plant could also have higher profits, presenting a payback period of 3.57 years. Finally, the new improved system is treated as a multi-objective optimization problem and it is solved by using the weighted sum method to obtain the Pareto frontier, providing the optimal solutions that trade-off economic and environmental objectives.