Product inhibition and the cost of downstream separations are two main barriers in using lignocellulosic biomass for bioethanol production. If bioethanol can be continuously removed from fermentation broth without affecting the fermentation process, significant gains can be achieved with bioethanol yields and process efficiency. Hot microbubble clouds generated by energy efficient means have been used to remove ethanol from dilute ethanol–water mixtures (∼4% [v/v]) maintained at 60 °C, and the effect of key operating parameters on the stripping rate has been studied. Numerical simulations of a hot microbubble rising in a dilute ethanol–water mixture were also performed to understand the instantaneous concentrations within the gas phase. Increasing the inlet gas temperature from 90 to 150 °C and decreasing the liquid height in the unit from 50 to 5 mm both increased the ethanol stripping rate. However, the benefit of increasing the gas temperature for maximum ethanol removal depended on the liquid height in the unit. Under all operating conditions, ethanol concentration was reduced below ∼2% [v/v] within ∼25 min of operation, demonstrating the potential of hot microbubble stripping for product removal from lignocellulosic fermenters. Implemented effectively in a fermenter, this technology could intensify the bioethanol production process and improve process economics.

中文翻译：

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乙醇-水稀释混合物的热微气泡汽提

产物抑制和下游分离的成本是使用木质纤维素生物质生产生物乙醇的两个主要障碍。如果可以在不影响发酵过程的情况下从发酵液中连续去除生物乙醇，那么生物乙醇的产量和工艺效率将大大提高。通过节能方法产生的热微气泡云已用于从维持在60°C的稀乙醇-水混合物（〜4％[v / v]）中除去乙醇，并且研究了关键操作参数对汽提率的影响。为了了解气相中的瞬时浓度，还对在稀乙醇-水混合物中升起的微气泡进行了数值模拟。将进气温度从90°C升高到150°C，并将装置中的液体高度从50 mm降低到5 mm，都可以提高乙醇的汽提率。但是，增加气体温度以最大程度地去除乙醇的好处取决于装置中的液体高度。在所有操作条件下，乙醇的浓度在约25分钟内降低至约2％[v / v]以下，这表明热微泡汽提具有去除木质纤维素发酵罐中产物的潜力。在发酵罐中有效实施该技术可以增强生物乙醇的生产工艺并提高工艺经济性。在运行的约25分钟内，乙醇浓度降低到约2％[v / v]以下，这表明热微泡汽提具有从木质纤维素发酵罐中去除产物的潜力。在发酵罐中有效实施该技术可以增强生物乙醇的生产工艺并提高工艺经济性。在运行的约25分钟内，乙醇浓度降低到约2％[v / v]以下，这表明热微泡汽提具有从木质纤维素发酵罐中去除产物的潜力。在发酵罐中有效实施该技术可以增强生物乙醇的生产工艺并提高工艺经济性。