What is the function of Pall ring packing? What types are there?

First, let’s get to know the packed tower. The packed tower includes cooling tower, distillation tower, extraction tower, desorption tower, washing tower, etc. The tower equipment is one of the most important equipment in chemical industry, petrochemical industry, and oil refining production. It can make gas The two liquid phases are in close contact to achieve the purpose of interphase mass transfer and heat transfer. The packing is a mass transfer carrier as a contact component between the gas and liquid phases. The tower body of the packed tower is a vertical cylinder with a packing support plate installed at the bottom. The Pall ring packing is placed on the support plate in a random pile or in a complete manner. On the other hand, if the Pall rings are of small size, they can be piled randomly, and if the Pall rings of large size are customized, they can be assembled in a complete way.
A packing pressure plate is installed above the Pall ring packing to prevent it from being blown by the upward airflow. The liquid is sprayed from the top of the tower to the packing through the liquid distributor and flows down along the surface of the packing. The gas is fed from the bottom of the tower and distributed through the gas distribution device. Afterwards, it continuously passes through the gaps in the packing layer in counter-current with the liquid. On the surface of the packing, the gas and liquid phases are in close contact for mass transfer. The packed tower is a continuous contact gas-liquid mass transfer equipment. The two-phase composition changes continuously along the height of the tower. Under normal operating conditions, the gas phase is the continuous phase and the liquid phase is the dispersed phase.
The types of Pall ring packing will also vary according to the material, and the corresponding performance will also be different. No matter what kind of material the Pall ring is made of, it has the characteristics of high specific surface area utilization, small air flow resistance, uniform liquid distribution, and high mass transfer efficiency. At the same time, the performance of different materials will be slightly different. For example, ceramic Pall rings have good corrosion resistance, plastics have good temperature resistance and great operating flexibility, and metal Pall rings have good antifouling effect.
The working principle of Pall ring packing is that when the liquid flows downward along the packing layer, it has a tendency to gradually concentrate toward the tower wall, causing the liquid flow near the tower wall to gradually increase. This phenomenon is called wall flow. The wall flow effect causes the gas and liquid phases to be unevenly distributed in the packing layer, thus reducing the mass transfer efficiency. Therefore, when the filler layer is high, it needs to be segmented and a redistribution device is installed in the middle. The liquid redistribution device consists of 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 distributor. After redistribution, it is spray-painted onto the lower Pall ring packing. After placing Pall ring packing in the packed tower, the problems of wall flow and channel flow can be solved.