Study On Dual Temeprature Control Of Batch Distillation

The models for cyclic total reflux operation were established in this paper. A controlling method of batch distillation by introducing temperatures of middle and top part in batch distillation column is proposed. The top temperature is chosen as the controlling point of withdrawing the product and the set temperature of middle part is used as the switch of total withdraw to reflux. When we are setting the controlling temperature of middle part, we revise the setting method early proposed by others through adding the bottom temperature sensor. Moreover, the relation between the theoretical and practical plate is made use of to calculate the rising range of middle temperature to set the middle temperature controlling point. In this way, we deliver a precise calculating method to set the middle controlling data in advance in order to improve the purity of product and the recovery ratio.In this paper , isopropyl alcohol and n-propyl alcohol was used to conduct the experimental study of this operation. After comparing the dual-temperature controlling method with the traditional controlling method, we find out that the novel method not only adopts the advantages of the traditional method, but also makes the product qualified. Furthermore, introducing the controlling point of middle part temperature in column makes the quantity and quality of production better than that of the method only using top part temperature, and it makes controlling operation flexibility more high. After comparing the middle controlling point set by the theoretical plate method with the method purely depending on experience, we find out that the improved setting method reduces the withdrawing time, enhances withdrawing efficiency and improves the purity and recovery ratio.