无累积罐循环全回流间歇精馏三温控制操作

提出了通过塔顶、塔中上以及塔中3个温度控制进行操作状态转换的无累积罐循环全回流间歇精馏控制方法，并以理想物系--乙醇-正丙醇混合物为分离物系进行了实验研究。通过实验确定了温度控制条件为当塔顶温度稳定后且塔顶和塔中上温差为0.3 ℃时变全回流为全采出操作，当塔中温度升高1.0 ℃时停止全采出转为全回流操作。同时还考察了在不同乙醇投料浓度条件下这种操作的运行情况，发现不同投料浓度对塔顶产品平均纯度的影响并不显著，基本能保持在0.99。最后在相同的投料浓度和操作条件下，对比了这种新型控制方式和双温度控制方式，结果表明三温度控制方式比双温度控制方式操作时间减少了23.3 min，分离效率提高了23.95%，产品浓度提高了1.06%，产品收率提高了1.08%。

Tri-temperature control method on cyclic total reflux batch distillation without reflux drum

A control method of total reflux by introducing temperatures of top part,upper-middle part and middle part in batch distillation column without reflux drum was proposed.The ethanol—n-propanol system identified as a typical ideal system was used to conduct the experimental study of this operation.The optimized temperature control conditions were determined by experiments:when the temperature of the top part was stable and difference between the upper-middle part and the top part was 0.3 ℃,the total reflux operation would be switched to the total withdrawal operation,and if the temperature of the middle part rose by 1 ℃,the total withdrawal operation should be converted to the total reflux operation.From the results of experiments under the same operating conditions,the influence of different feed concentrations on the overhead product average purity is not significant,basically maintained at 0.99(mass fraction).Finally,compared with dual temperature control method under the same feed concentration and operating conditions,this tri-temperature control method reduces operating time by 23.3 min,promotes separation efficiency by 23.95%,increases the purity of product by 1.06% and increases the product yield by 1.08%.