Stainless steel packed tower is one of the most important equipment in chemical industry, petrochemical industry and oil refining
Packed tower is a mass transfer equipment in which the packing in the tower is used as the contact component between gas and liquid. The body of the packed tower is a vertical cylinder, and the bottom is equipped with a packing support plate. The packing is placed on the support plate in a disorderly or integral way. The top of the packing plate is installed to prevent 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 packing surface. The gas is fed from the bottom of the tower and distributed through the gas distribution device (generally, no gas distribution device is set for small diameter tower), and then it flows with the liquid continuously through the gap of the packing layer. On the surface of the packing, the gas-liquid two-phase contact closely for mass transfer. The packed tower is a continuous contact gas-liquid mass transfer equipment. The two-phase composition changes continuously along the tower height. Under normal operation, the gas phase is continuous phase and the liquid phase is dispersed phase.
When the liquid flows downward along the packing layer, it tends to concentrate to the tower wall gradually, which makes the liquid flow near the tower wall increase gradually. This phenomenon is called wall flow. The wall flow effect results in the uneven distribution of gas and liquid phases in the packing layer, resulting in the decrease of mass transfer efficiency. Therefore, when the packing layer is high, it needs to be segmented and the redistributor should be set in the middle. The liquid redistributor consists of liquid collector and liquid redistributor. The liquid flowing from the upper packing is collected by the liquid collector and sent to the liquid redistributor. After redistribution, the liquid 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 operation flexibility.
The packed column also has some shortcomings, such as high cost of packing, low efficiency of mass transfer due to low liquid load, inability to directly use materials with suspended solids or easily polymerized materials, unsuitable for complex distillation such as side feed and discharge, etc.