A tray tower is a type of equipment used for分级contact mass transfer in gas-liquid or liquid-liquid systems, consisting of a cylindrical tower body and several trays spaced horizontally within the tower. It is widely used in distillation and absorption, and some types (such as sieve tray towers) are also used for extraction. It can also serve as a reactor for gas-liquid phase reaction processes. During operation (taking a gas-liquid system as an example), the liquid flows downward through each tray layer, from top to bottom, and is discharged at the bottom; the gas, propelled by a pressure difference, flows upward through each tray layer, from bottom to top, and is discharged at the top. Each tray maintains a certain depth of liquid layer, and the gas is dispersed into the liquid layer through the trays, where interfacial mass transfer occurs.