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.

生物乙醇是重要的生物燃料，具有成为化石燃料安全替代环境的潜力。然而，生物乙醇生产涉及许多蒸馏步骤，这是最耗能的分离方法之一。提出了非常规蒸馏技术，旨在降低能源成本和CO ₂生物乙醇生产中的排放。探索了精馏和精馏过程以及这些技术的新颖性。在所有建议的配置中，液相或气相均在塔内分配。首次研究了具有多个冷凝器的蒸馏塔和具有不同蒸馏技术的蒸馏塔，这些蒸馏塔组合成一个独特的塔壳，在此称为合并塔。在分馏塔中设置多个冷凝器可避免不必要的气相混合。合并的塔由精馏段中的蒸馏塔板和汽提段中的蒸馏塔或常规塔板组成。新配置降低了年度总成本和CO ₂与传统蒸馏相比，排放量分别高达35％和42％。与以前的结果不同，可以通过使用转移蒸馏而不是常规蒸馏来减小塔直径，而不会增加塔高度。因此，生物燃料和中性酒精的生产可以更加经济和可持续。