伴有简单蒸馏的间歇萃取精馏过程

Design and Operation of a Batch Extractive Rectification Column with a Bottom Equilibrium Distillation Still

提出一种伴有简单蒸馏的间歇萃取精馏的操作方式。新操作方式是在普通间歇精馏塔的基础上,在精馏塔底部连接一个间歇精馏塔釜和一个简单蒸馏釜。在精馏过程中,混有溶剂的塔内液相不流回塔釜,而是流入塔底简单蒸馏釜,经简单蒸馏的汽相返回塔釜,而富含溶剂的液相留在简单蒸馏釜中。以乙二醇为溶剂分离乙醇水物系的分析操作结果表明,与普通间歇萃取精馏操作相比较,新操作方式克服了普通间歇精馏操作中塔釜容积过大的问题,同时具有在操作过程中塔釜温度上升幅度很小、操作时间短、溶剂回收简便等优点。

A new method of batch extractive distillation (BED) with solvent recovered by an additional equilibrium distillation still was provided.The new type batch extractive rectification column system consisted of a rectification column,a batch reboiler and an additional equilibrium still in bottom.The liquid in the column containing solvent did not flow into batch reboiler,but into equilibrium distillation still,from which only vapor phase flowed into batch reboiler and solvent was kept in equilibrium distillation still.The nature of operation was analyzed during separation of ethanol-water azeotrope using glycol as solvent.Comparing with common batch extractive distillation (CBED) operation,the new method possessed some major advantages.The new method could avoid large volume problem of batch reboiler in BED.The temperature of reboiler increased only mildly during the process and operation time was shorter while keeping same purity and yield of product.The solvent recovery was simple and effective in new operation.