Parastillation And Metastillation Applied To Bioethanol And Neutral Alcohol Purification With Energy Savings

Bioethanol is an important biofuel with high potential to be a safety environmental alternative to fossil fuels. However, bioethanol production involves many distillation steps, which is one of the most energy consuming separation processes. Unconventional distillation techniques were proposed, aiming to reduce energy cost and CO2 emissions on bioethanol production. Parastillation and metastillation processes and novelty combinations of these techniques were explored. In all proposed configurations the liquid or vapor phase was divided inside the column. For the first time, parastillation columns with multiple condensers and columns with different distillation techniques combined into one unique column shell, here denominated as combined columns, were studied. Multiple condensers set, in parastillation columns, avoids the non-necessary mixed of the vapor phases. Combined columns are composed of parastillation trays in the rectifying section and of metastillation or conventional trays in the stripping section. The new configurations reduce total annual costs and CO2 emissions up to 35 % and 42 %, respectively, when compared with traditional distillation. Reduction in the column diameter by using metastillation instead of conventional distillation was possible without an increase in the column height, differently from previously results. Therefore, biofuel and neutral alcohol production can be even more economical and sustainable.