先加入溶剂的间歇萃取精馏实验研究

Study on Batch Extractive Distillation with Adding Solvent before Ebullition

针对常规间歇萃取精馏操作中产品采出前建立平衡过程复杂、能耗较高的问题,提出了一种新的间歇萃取精馏操作方式,即在精馏塔釜液接近泡点时,就将溶剂以一定流量连续加入精馏塔,当蒸汽上升至塔顶就以一定的回流比采出产品.因此在产品采出之前,只需要建立一次汽—液平衡关系.本文以乙二醇为溶剂分离乙醇—水体系,通过与常规间歇萃取精馏操作方式的对比实验表明,新的操作方式具有操作简单,操作时间短,能耗低等优点.

One of the main shortcomings of common batch extractive distillation （CBED） is difficult to control the process, because the vapor-liquid equilibrium must be established three times before collecting products, and the energy consumption of CBED is high in this step. A new process of batch extractive distillation （BED） was proposed in this thesis. In the new operation, the solvent was added to the still before boiling, therefore the vapor-liquid equilibrium was established only once before collecting products under finite reflux ratio with solvent feeding. The azeotrope of ethanol-water was separated by the new BED using glycol as solvent. Comparing with the common batch extractive distillation, the new BED had the advantages of operating simply, short and economically.