双储罐替代恒全回流半连续精馏操作方式的研究

Study on operation mode of vessels-alternated semi-continuous distillation with constant total reflux

提出双储罐替代的恒全回流半连续精馏操作方式(SCTR),该操作方式中塔顶和塔釜的双储罐分别交替使用,使精馏塔处于恒全回流状态,并能进行半连续地产品采出和原料补充。通过Matlab编程进行模拟,以轻重组分回收率、单位时间总产量(P.I.)等作为指标,在不同进料情况下对各参数的优化,包括储罐总体积、各储罐体积等。模拟结果表明,SCTR操作方式与恒回流比间歇精馏操作方式相比,最多可节省操作时间32%,与塔顶单储罐动态累积循环全回流间歇精馏相比,操作时间相近,与多储罐动态累积循环全回流间歇精馏操作方式相比,耗时略高。适用于轻组分浓度低的二元组分的分离。采用乙醇/正丙醇物系验证了该操作方式在进料浓度分别为0.2、0.5和0.8情况下的可行性和操作的简单灵活。

The present work proposed a new operation mode named the vessels-alternated semi-continuous distillation with constant total reflux(SCTR).In the new mode,the column was under total reflux all the time with two reflux drums working in turn at both the top and the bottom,respectively.A simulation was conducted by Matlab to study the discharging policy and optimize the operating parameters including the total holdup and distribution of vessels.The optimization was done according to the product yield both of light and heavy components,as well as the amount of total product per unit time(P.I.).Compared with operation mode of constant reflux(CR),SCTR can save the operation time by more than32%.It took almost the same time to operate compared with CTR with one vessel,but more time than the MVBD with three vessels.The results showed that the SCTR operation was more suitable for separation of binary mixtures with low concentration of light component.But it was advantageous in realizing semicontinuous operation by discharging product and replenishing feed periodically.Experiments with ethanol-propanol system in different feed concentrations(0.2、0.5and0.8)were presented,which confirmed the operation feasibility and simplicity of the new operation mode.