intermittent azeotropic distillation

Intermittent distillation combines the characteristics of simple distillation and conventional rectification. It is particularly suitable for the fine chemical industry. It is divided into distillation with a constant reflux ratio and distillation with a constant component concentration. . I’ll give you the specific principles and calculations later tonight; I’m in an elective class right now. ~~Hehe.

Characteristics of the batch distillation process: When high standards are required for the separation of mixed liquids, and the type or composition of the feedstock frequently changes, the batch distillation approach offers greater flexibility. From the perspective of distillation units, batch distillation is roughly similar to continuous distillation. In batch distillation, the feed liquid is added to the distillation vessel in batches, gradually heated and vaporized; once the composition of the liquid in the vessel drops to the specified value, it is discharged all at once. It is thus easy to understand that the batch distillation process has the following characteristics. 　　① Intermittent distillation is a non-steady-state process. During the distillation process, the composition of the bottom liquid continuously decreases. If the reflux ratio is kept constant during operation, the composition of the distillate will decrease accordingly ； Conversely, to maintain a constant composition of the distillate, the reflux ratio must be increased continuously during the distillation process. To meet the predetermined requirements, the actual approach can be flexible and varied. For example, at the beginning of the operation, the reflux ratio can be increased gradually to maintain a roughly constant composition of the distillate ； However, an excessively high reflux ratio is not economically reasonable. Therefore, the reflux ratio can be kept constant during the later stages of operation; if the obtained distillate does not meet the requirements, this portion of the product can be combined with the next batch of raw material for further distillation. 　　Furthermore, due to the non-steady state nature of the process, the amount of liquid accumulated in the tower (the liquid holdup) will affect the distillation process and the quantity of the product. To minimize the liquid holdup, packed columns are often used in batch distillation. 　　② In batch distillation, the entire column is a distillation section, with no stripping section. Therefore, to obtain a product with the same top and bottom composition, the energy consumption of batch distillation must be greater than that of continuous distillation. 　　The design calculation method for batch distillation begins with selecting a reference state (usually the initial or final state of operation) for the calculations, in order to determine the number of trays required. Then, based on the given number of theoretical plates, the reflux ratio or product composition at other states during distillation is determined using operational calculation methods.

Original poster, this is my QQ: 80202712. We have just systematically finished studying the batch distillation section of Chemical Engineering Principles. There are many calculations related to the principle of batch distillation; I can’t write them all down. Add me on QQ and I’ll tell you.

Isopropyl alcohol and water can form an azeotrope, and conventional distillation finds it difficult to separate the components of this azeotrope. As for batch equilibrium distillation, I’m not sure what the original poster means; laboratories generally use conventional distillation methods for such purposes. A double-column separation system is commonly used in industry to separate these two