Abstract

Direct contact membrane distillation (DCMD) was evaluated as an alternative for the treatment of sugarcane stillage obtained in the bioethanol production process. First, a synthetic stillage solution was prepared in order to study the influence of the main operational parameters of DCMD in the permeate flux, as well as to analyze the separation of volatile components (such as ethanol and acetic acid) and the concentration of non-volatile components presented in the feed stream (sucrose and other salts). Secondly, an industrial sample of sugarcane stillage was treated using DCMD. The highest flux achieved was 13.4 kg/m²·h for a transmembrane temperature difference of 55 °C, reaching a recovery degree of 70% with a specific thermal energy consumption of 671 kWh/m³. Then, sugarcane stillage was concentrated until 60°Brix. A preliminary economic study was also presented, an estimated cost of 1.25 $ per m³ of recovered permeate was obtained without any heat integration or DCMD operational optimization. DCMD showed to be suitable for stillage disposal allowing to recuperate the permeate stream as process water (containing mainly water and a low concentration of volatile components) and the concentrated stillage as biofuel to be used in the steam boiler (for producing more energy making the process thermally sustainable) or for ferti-irrigation (for reducing the transportation cost due to the volume reduction).

Graphic Abstract

中文翻译：

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直接接触膜蒸馏法处理甘蔗蒸馏酒

摘要

评价了直接接触膜蒸馏（DCMD）作为生物乙醇生产过程中获得的甘蔗蒸馏的替代方法。首先，制备合成釜馏溶液，以研究DCMD的主要操作参数对渗透通量的影响，并分析挥发性成分（例如乙醇和乙酸）的分离以及非挥发性成分的浓度。进料流中存在的挥发性成分（蔗糖和其他盐）。其次，使用DCMD处理了甘蔗蒸馏酒的工业样品。跨膜温差为55°C时，最高通量为13.4 kg / m ² ·h，回收率达到70％，单位热能消耗为671 kWh / m ³。然后，将甘蔗蒸馏物浓缩至60°白利糖度。还提出了一项初步的经济研究，在不进行任何热集成或DCMD操作优化的情况下，估计回收成本为每m ³ 1.25美元。DCMD被证明适合处理釜馏物，可以将渗透物流作为工艺用水（主要含有水和低浓度的挥发性成分）进行回收，而浓缩釜馏物可以用作蒸汽锅炉中的生物燃料（用于产生更多能量，从而使工艺得以恢复）热可持续性）或肥力灌溉（由于体积减少而减少运输成本）。

图形摘要