Structural Principle of Gas Solenoid Valve Packing Tower

Packed tower is a mass transfer equipment in which the packing in the tower is used as the contact member between gas and liquid phases. The tower body of the packed tower is a straight vertical cylinder (as shown in the figure above), and the bottom is equipped with a packing supporting plate, and the packing is placed on the supporting plate in a random pile or a whole building. A packing pressure plate is installed above the packing to prevent it from being blown by the updraft. The liquid is sprayed onto the packing through the liquid distributor from the top of the tower and flows down the surface of the packing. The gas is fed in from the bottom of the tower, and after being distributed by a gas distribution device (small diameter towers generally do not have a gas distribution device), it continuously passes through the gap of the packing layer in countercurrent with the liquid. On the packing surface, the gas and liquid two phases are in close contact for mass transfer . The packed tower is a continuous contact type gas-liquid mass transfer equipment. The two-phase composition changes continuously along the tower height. Under normal operating conditions, the gas phase is the continuous phase and the liquid phase is the dispersed phase.

　When the liquid flows down the packing layer, there is a tendency to gradually concentrate on the tower wall, making the liquid flow near the tower wall gradually increase. This phenomenon is called wall flow. The wall flow effect causes uneven distribution of the gas and liquid phases in the packing layer, thereby reducing the mass transfer efficiency. Therefore, when the packing layer is high, it needs to be segmented with a redistribution device in the middle. The liquid redistribution device includes a liquid collector and a liquid redistributor. The liquid flowing down from the upper packing is collected by the liquid collector and sent to the liquid redistributor. After being redistributed, it is sprayed onto the lower packing.

　The packed tower has the advantages of large production capacity, high separation efficiency, small pressure drop, small liquid holding capacity, and large operating flexibility.

Packed towers also have some shortcomings, such as the high cost of packing; when the liquid load is small, the surface of the packing cannot be effectively wetted, which reduces the mass transfer efficiency; it cannot be directly used for suspended solids or easily polymerized materials; Complex distillation such as discharging is not suitable for waiting.