A mathematical, economic and energetic appraisal of biomethane and biohydrogen production from Brazilian ethanol plants' waste: Towards a circular and renewable energy development

The high production of sugarcane in Brazil and its application of ethanol and sugar production results in a higher generation of vinasse and bagasse. The treatment of these residues can be carried out using anaerobic co-digestion procedures. Besides promoting waste treatment, it enables energy exploration through biogas and hydrogen generation. Bioenergy use can also generate steam in sugar and alcohol plants by burning, sugarcane milling, fueling vehicles for the transport of products, among others. These energy applications allow total and efficient, energetic exploring of sugarcane. Hence, this study estimated the production of methane, hydrogen, thermal and electrical energy generated from vinasse and bagasse in the autonomous and annexed Brazilian ethanol and sugar plants. Three scenarios present the use of biogas generated: Scenario 1: energy use of all methane from biogas; Scenario 2: hydrogen production from the remaining methane, after considering the energy autonomy of the ethanol plants; Scenario 3: hydrogen production from all the methane generated. All the scenarios which considered the use of methane led to energy self-sufficiency in the sector. However, only annexed plants present economic feasibility for implementing the project. Scenario 2 is highlighted in this study, once beyond the sectors energetic self-sufficiency, the operational conditions enabled the storage of 9.26E+07 Nm(3).d(-1) of hydrogen, equal 3.04E+08 ton per year. CH4 and H-2 production seen in a global scenario of circular economy and energy security have high benefits, contributing to the gradual transformation of an economy dependent on nonrenewable resources into a circular and renewable economy. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study focuses on the production of methane, hydrogen, thermal and electrical energy from vinasse and bagasse in Brazilian ethanol and sugar plants. Different scenarios show that the use of biogas can lead to energy self-sufficiency in the sector, with Scenario 2 being highlighted for its operational conditions enabling the storage of hydrogen.