Simulation of Dilute Acid Hydrolysis of Banana Waste for Ethanol Production: Comparison between the Use of Fruits, Peel and Pseudostem

Abstract

Banana waste has been used to produce bioethanol with the goal of developing a low-cost, sustainable production method. Brazil, which annually generates large amounts of agro industrial waste, has high technological potential in this area. The pseudostem, peel and the fruit can be used and studies are focused on the hydrolysis because it has been proven that this step involves the highest production cost. The goal of this study is to evaluate the acid hydrolysis of banana residues using simulation. It was used the Aspen HYSYS® software simulating the heating, hydrolysis, neutralization and cooling process, from experimental data previously evaluated. A conversion reactor was used and the reactions of cellulose to glucose and that to the hydroxymethylfurfural (HMF) were implemented. Calculation was made in order to obtain the conversion for the optimum conditions of previous work: 120°C, 2 % (weight) H2SO4 and residence time in reactor of 15 min. For these conditions a conversion of cellulose to glucose of 36 % can be obtained when pseudostem was used. Tests were performed with this value for three residues mentioned and then the conversion was increased gradually to the maximum value (100 %). Even known that the conversion of lignocellulosic residues is around 40-60 %, we aimed to corroborate the results previously obtained in the laboratory with data that have not been evaluated experimentally, as the energetic condition of the process and HMF production. The analysis of the energy consumption per sugar produced demonstrated that the hydrolysis of banana fruit residue (pulp) is unattractive as shown experimentally. This behaviour is independent of the increased conversion process. For hydrolysis of the pseudostem was observed that there is a decrease in the amount of energy required in respect of glucose produced to near 80 %, from which the gains with increasing conversion are few.