关键词: 1, 3-丙二醇, 多效蒸发, 浓缩, 模拟

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