Energy and environmental analysis of vinasse processing using internal circulation biodigesters and concentrators for different production ranges of ethanol and its potential impact on Brazil

Abstract

Vinasse is one of the worst waste products in the production of ethanol. However, it can be used to generate biogas, electricity, and carbon credits from biodigesters and concentrators. Thus, studying the use of vinasse is justified, and this study asks the following research question: How feasible is it to use internal circulation biodigesters with the vinasse concentrator Citrotec®, and their conjugates in energy and environmental terms? To answer this question, the study employs quantitative methodology. To analyze this in terms of energy, the consumption of diesel in vinasse logistics has been calculated, the balance of energy in its processing and transport, its generation of electricity, and its capacity in terms of storage in urban centers. It has also been in terms of its incremental capacity in the production of cellulosic ethanol, the generation of electricity, and substitution for diesel, gasoline, and ethanol in the states of Brazil. The environmental analysis includes the balance and emission and mitigation of nitrous, sulfur, and carbon oxides in the processing and transport of vinasse, as well the figures for each Brazilian state that produces ethanol and the potential gains in the carbon credit market. The principal innovations of this article are a detailed analysis of the production ranges for autonomous sugar energy plants with a range of production from 500 to 4000 m3/day, the processing and logistics of vinasse for planting, as well as an analysis of each Brazilian state for the 2015/2016 crop. According to our results and review of the literature, the reuse of vinasse is recommended due to its energy and environmental gains, in a way that maintains the fertilizing and irrigation characteristics of the residues, particularly the IC biodigesters and concentrators and their conjugates.