Compared with plate column, packed column has certain advantages, especially in recent years, a variety of new and efficient packing has been developed, which has more prominent advantages and wider application range. Its specific characteristics are as follows:
1. The pressure drop is very low, which can be used in vacuum distillation and other operating systems with limited pressure drop.
2. With the development of new high efficiency packing, the production capacity (allowable gas velocity) and efficiency of packed tower are equal to or exceed those of plate column. Many units at home and abroad use new packing to transform plate column, which greatly improves production capacity and efficiency.
3. Flexible operation.
4. It can deal with foaming system.
5. General fillers are easy to be blocked by suspended solids in the liquid, while some grid fillers with large void fraction have self-cleaning effect under high gas velocity scouring, and are not easy to be blocked, and their heat transfer performance is better than that of baffles.
6. The material selection of fillers is wide, such as metal, plastic, ceramic, graphite, etc., which is suitable for wider chemical system and operating system.
7. Small liquid holding capacity, suitable for the treatment of heat sensitive materials.
8. The total investment cost of small tower (diameter ≤ 0.6m) is lower than that of plate tower, but the investment cost of large tower is higher.
9. The heat exchange in the middle of the tower is inconvenient.
10. It is difficult to draw out the side line and the structure is complex.
11. High requirements for initial gas-liquid distribution.
The process control is difficult because of its small liquid holding capacity and sensitivity.