Performance and cost evaluation of a new double-effect integration of multicomponent bioethanol distillation

Bioethanol derived from sugarcane is the most advanced alternative to fossil fuels and part of the solution in the efforts to achieve a low-carbon emissions world. Since distillation accounts for a large part of total energy consumption by industry, the need to reduce energy requirements serves as motivation for the study of this process. Many energy efficient schemes have been developed with this aim. However, most of them focus on columns working under pressure. Due to the organic nature of sugarcane and also to the liming process to which its juice is submitted, significant fouling can result from the insolubility of calcium salts, which is intensified at higher temperatures. In this work, Aspen Plus® was used to investigate the energy requirement of a configuration of double-effect forward-integrated columns, considering an extra stripping section to reduce the risk of fouling. The wine was considered a multicomponent mixture. Response surface methodology was applied to optimize the process and analyze some operating parameters. The configurations studied were adequate, but involved higher investments. The total annual costs were observed to be lower than those of a conventional process. Finally, congeners tended to have a negative effect on the specific steam consumption of the process.