Desempenho de uma coluna de destilação, frente à variação das concentrações e vazões de alimentação utilizando-se solução hidroalcoólica padronizada

Abstract

In Brazil, especially in Rio Grande do Sul, there is a significant increase in ethanol production in small scale, i.e. in micro distilleries. These small-scale distilleries benefit small farmers, decentralize ethanol production and are based on the economic, social and environmental issue, but they do not hold enough technology that enables high performance in their processes, especially in the distillation stage. View of all this, it has developed this work, which aims to study the performance of a distillation column in permanent regime, developed and built at the Laboratory for Post-Graduate Processes Engineering using as feed a commercial ethanol solution and water, varying the concentration and the input flow into the column. It was opted for a standardized solution in order to achieve free results from interference by possible impurities. The concentration and flow of feed were set as independent variables and their limits established respectively in 5 and 9 °GL (% by volume) and 1848-4385 g/h. The concentrations of the distillate and of the bottom product were defined as dependent variables. Eleven tests were carried out according to the methodology of planning of experiments by using a central composite rotatable delineation, with triplicate at the central point. Three samples of distillate and bottom product were collected in flasks with lids, at intervals of fifteen minutes. Data were tabulated in spreadsheets from excel. Statistical analysis, using the software Statistica 7th version, was performed to evaluate whether the parameters: ethanol concentration and input flow of feed product interfere in the obtaining ethanol in patterns determined by ANP Resolution n°. 7, February 9th, 2011, i.e., Hydrous Ethanol Fuel (HEF) with ethanol concentration between 92.5 - 93.8°INPM. It was observed that, for the distillate, feed concentration and input flow, both in the quadratic form, are significant, i.e., there is the influence of these two variables in the obtaining of ethanol with higher alcoholic strength, but it was not able to reach the standard established by resolution of ANP. For the bottom product, it was found that neither concentration nor the input flow influence in their alcoholic concentration, possibly by design of the studied column.