Análise da produção de etanol a partir da casca de arroz utilizando o software Unisim® Design

Abstract

Current environmental policies seek to reduce energy consumption and waste disposal into the environment, through research and development of alternatives generally linked to renewable sources. The use of biomass from agro-industrial residues such as rice husk for energy generation is a good alternative both for the production of bioethanol and as a new destination for waste. The method used to obtain second generation ethanol using lignocellulosic raw materials - such as rice husk - is through acid hydrolysis followed by fermentation and distillation. This process can be planned, analyzed and optimized using specialized software for process simulation, such as UniSim® Design. Thus, with interest in the development of the Bagé region, the present study consisted of producing a simulation of the process of obtaining ethanol from rice husks using the UniSim® Design software as well as conducting studies of the optimum conditions of the process. The simulation was carried out from a conversion reactor as an adaptation for the fermentation process followed by separation steps in order to achieve the highest purity of ethanol within the process parameters used. Regarding the purity of the ethanol obtained as well as the other products of the process, the simulation study showed better results when compared to the literature, however it is still necessary to add new purification steps in the flowchart in order to obtain more refined products. In a general analysis of all steps involved in obtaining ethanol, the production of bioethanol obtained in the process is about 2,338.0 L/h with a purity of 66.3% of ethanol from 3.042 t/h of rice husk. It was also possible to obtain a theoretical ethanol yield of 150.7 L/t, a real yield of 78.25 L/t and a process efficiency of 51.9%. In addition, based on the study of the optimum process conditions, it is possible to achieve a purity of 66.57% ethanol with a biomass/water ratio of 1:2.75 as a feed current obtained through the study of optimum process conditions.