Abstract:

1,3-propandiol(PDO) and water concentration in fermentation broth are usually in the range of 7%-10% and 82%-85%. In the downstream processing of PDO recovery,dehydration by evaporation is the most energy intensive with the most PDO loss. In this work,the dehydration process of filtered fermentation broth by evaporation was simulated with Aspen Plus software. The effect of operation pressure on the water content in the concentrate and POD recovery yield was investigated, and the efficiency of multi-effect evaporation process in cocurrent,cross and countercurrent flow operations was compared. It was found that POD loss increased with the decrease of the required water content in the concentrate and increase of operation pressure. When the operation pressures were 5kPa, 100kPa and 150kPa,to obtain 30% of water content in the concentrate,the PDO loss was simulated to be 4.63%,20.04% and 24.78%,respectively. However,PDO loss increased to 23.68%,76.62% and 84.95%,respectively,when the required water content decreased to 12.5%. The concurrent flow multi-effect evaporation achieved the highest PDO recovery,reaching 97.73% at 30% of water content in the concentrate with steam consumption of 0.354 ton to evaporate 1 ton water.

Key words: 1,3-propanediol, multi-effect evaporation, concentrate, simulation

摘要：

1，3-丙二醇（PDO）发酵液中PDO浓度7%～10%，水含量82%～85%，PDO分离提取各工序中蒸发脱水能耗最大、PDO损失率最大。本文利用Aspen Plus软件对PDO发酵液蒸发脱水过程进行了模拟，研究了操作压力与蒸发脱水终点浓缩液中水含量对蒸发脱水过程中PDO收率的影响，比较了并流、逆流和错流多效蒸发流程进行PDO发酵液脱水的优缺点。研究结果表明，PDO发酵液蒸发脱水过程中PDO损失率随浓缩液中水含量降低和操作压力增大而增大，PDO发酵液在操作压力分别为5kPa、100kPa、150kPa的3种条件下蒸发脱水至浓缩液含水量为30%时，PDO损失分别为4.63%、20.04%和24.78%，PDO发酵液在3种不同操作压力条件下浓缩至浓缩液含水量为12.5%时，PDO损失分别增大到23.68%、76.62%和84.95%；并流蒸发流程PDO收率最高，浓缩液含水量30%，PDO收率97.73%，蒸发1t水消耗0.354t蒸汽。

关键词: 1, 3-丙二醇, 多效蒸发, 浓缩, 模拟