The distillation tower is a tower-type vapor-liquid contact device for distillation, also called a distillation tower. There are two main types: plate tower and packed tower. According to the operation mode, it can be divided into continuous distillation tower and batch distillation tower. According to the operating pressure, it can be divided into three types: normal pressure, pressurized and reduced pressure. The basic principle of distillation is to partially vaporize and partially condense a liquid mixture multiple times,Taking advantage of the different volatilities of each component (relative volatility,α) characteristics to achieve unit operations for separation purposes. Distillation can be divided into simple distillation, flash distillation, rectification and special distillation according to its operation method.