Estudo exploratório do processo de biossecagem aplicado ao controle de umidade da biomassa de cana de açúcar

Abstract

In Brazil, each metric ton of sugarcane processed in sugar and ethanol mills generates approximately 250 kilograms of biomass in the form of sugarcane bagasse, resulting in an annual production ranging from 5 to 12 million metric tons of this residue. Sugarcane bagasse can be used as an energy source through combustion process. However, sugarcane biomass must be subjected to a moisture control process in order to optimize operation conditions during the combustion. Conventional drying processes are highly costly, so an alternative involves the use of biological heat generated by microbial activity to remove water from the system. This process, known as biodrying, relies on the metabolic activity of microorganisms present in the biomass, which can generate temperatures of up to 70 °C. Nevertheless, studies on biodrying remains limited and there is a significant demand for scientific studies that optimize the development of this process for industrial scale drying of organic solid waste. Therefore, the objective of this study is to present an exploratory investigation of the biodrying process applied to moisture control in sugarcane biomass, utilizing native microorganisms from the biomass. The thermal profile of the system and the mass loss over time were monitored to support the development of process intensification strategies. Three experiments were conducted, adopting a fixed bed configuration, with variations in operating time, aeration regime, initial biomass humidification and turning processes. The results demonstrate that, in the first two short-term experiments, there was no significant increase in temperature and mass loss was minimal, indicating limited microbiological activity. In contrast, the third experiment, which lasted 30 days, employed continuous aeration and periodic turning, resulting in improved thermal performance and a greater mass reduction. However, the temperature values did not reach characteristics of efficient biodrying (above 40°C). The total mass loss was 1,7 kilograms, indicating partial moisture removal and some microbiological activity. The results indicate that the method is promising but the operational conditions require optimization.