Energy analysis of the ethanol industry considering vinasse concentration and incineration

Nowadays, the ethanol represents the most consolidated biofuel in Brazil. Despite presenting environmental advantages in comparison with non-renewable fuels, the concern for the ethanol process residues is increasing. Among these residues, the vinasse, bottom product of distillation process, is the most important since its characteristics such as BOD, acidic nature and large volume make its disposition difficult and costly. The aim of this study is the integration of a vinasse concentration and incineration system to a conventional sugar, ethanol and electricity production process. For this study, the Aspen Plus® software was used to simulate the production process. Assuming a sugar-ethanol production plant, different scenarios were analysed considering vinasse concentration with a multiple-effect evaporator system, vinasse incineration with salt recuperation, and heat integration. In scenarios that do not assumed heat integration, the main results show that vinasse incineration is necessary to contribute to the steam generation in order to cover the steam demand of the process, including the vinasse concentration. Regarding the heat integration procedure, an appropriate placement of evaporators was achieved through the reduction of the number of effects on both the vinasse and juice evaporation systems; thus promoting a meaningful reduction in the steam consumption of the integrated process1429610