Isoamyl alcohol production integrated with hydrous ethanol production

Bioethanol produced from sugarcane is a great alternative to produce biofuels for Brazil. The energy demand and better utilization of by-products are areas with large potential improvements in the ethanol production process. The ethanol industry in Brazil has experienced successive increases in demand and production. This expansion of ethanol productivity will allow more profitable uses of products such as fusel oil, a mixture of various alcohols such as isobutanol, ethanol, propanol and, especially, isoamyl alcohol. Such alcohols have applications in various industries. However, current applications of fusel oil presents low economic benefits for ethanol mills. Energy demand is another point that has great impact on increasing the sustainability and profitability of bioethanol production. The development of more efficient distillation technologies is very important because this unit operation is responsible for a considerable part of the utilities and investment costs in ethanol production. Moreover, this reduction in steam consumption can increase the quantity of bagasse available to be used for bioelectricity or cellulosic ethanol production. In these circumstances, the present study aims to investigate processes that increase the economic benefit and sustainability of ethanol production by reducing utilities and equipment distillation costs or by manufacturing of products with higher added value. With the premise of having relative ease application, the following processes are investigated: integrated process for isoamyl alcohol and ethanol production; use of high energy efficiency columns distillation for multi-component separations (divided wall column and multi-effect columns; energy demand optimization of the conventional distillation process of ethanol; distillation process of fusel oil to obtain ethanol, isoamyl alcohol and butanol. The integrated production of ethanol and isoamyl alcohol allows increasing the recovery of ethanol and producing isoamyl alcohol and its isomer active amyl alcohol with high purities from fusel oil. However, energy integration using a multi-effect distillation columns for the integrated process was not an economically viable alternative due to the small temperature differentials obtained for energy transfer between columns. To make better use of other constituents of fusel oil, the investigation of an autonomous plant configuration for butanol, isoamyl alcohol and ethanol recovery from fusel oil was investigated, this process shows high recovery rates of these components by a process that does not use solvents and employs only conventional distillation columns and decanters. An additional contribution of this thesis is to demonstrate the influence of phlegm concentration on energy demand costs of industrial ethanol distillation. The optimal economic conditions allow savings in energy demand of about 15% in the current ethanol plants, only by controlling the composition of phlegm. The process of hydrated ethanol production using a Divided Wall Column (DWC) was developed and optimized. Compared with the conventional sequence of two distillation columns, the DWC proposal presented lower costs of utilities and equipment (AU)