What is the diameter of the tower to choose a plate tower or a packed tower? Don’t hesitate to teach me

Factors that should be considered when choosing a tower type include:: Material properties, operating conditions, performance of tower equipment, and manufacturing, installation, transportation and maintenance of tower equipment, etc. a. Factors related to physical properties (1) For materials that are prone to foaming, such as when the processing capacity is not large, it is better to choose a packed tower. Because packing can cause foam to burst, it can easily cause flooding in plate towers. (2) For corrosive media, a packed tower can be used. If a plate tower must be used, a sieve plate tower, cross-flow tray or tongue-shaped tray with simple structure and low cost should be used to facilitate timely replacement. (3) When heat-sensitive materials need to be operated under reduced pressure to prevent decomposition or polymerization caused by overheating, a tower type with a smaller pressure drop should be selected. For example, a tower filled with structured packing, a wet wall tower, etc. can be used. When a low vacuum degree is required, a sieve plate tower and a float valve tower should be used. (4) For systems with greater viscosity, large-size fillers can be used. The mass transfer efficiency of the plate tower is too poor. (5) For materials containing suspended solids, a tower type with a larger liquid flow channel should be selected, preferably a plate tower. Bubble towers, float valve towers, grid towers, tongue towers and sieve towers with larger apertures can be used. Small fillers should not be used. (6) For systems with thermal effects during operation, it is appropriate to use a plate tower. Because there is a liquid layer on the tray, heat exchange tubes can be placed in it for effective heating or cooling. b. Factors related to operating conditions (1) If the gas phase mass transfer resistance is large (i.e. gas phase control system, such as distillation of low-viscosity liquids, air humidification, etc.), a packed tower should be used because the gas phase in the packing layer is turbulent and the liquid phase is a film flow. On the contrary, for systems controlled by the liquid phase, a plate tower should be used because the liquid phase in the plate tower is turbulent and gas is used to bubble the liquid layer. (2) For large liquid loads, a packed tower can be used. If a plate tower is used, a tower type with gas-liquid co-current flow (such as a jet tray) or a tower type with smaller liquid flow resistance on the plate (such as a sieve plate and a float valve) should be selected. In addition, both guided screen trays and multi-downcomer screen trays can withstand larger liquid loads. (3) For low liquid loads, packed towers are generally not suitable. Because packed towers require a certain amount of spray density, mesh packing can be used in low liquid load situations. (4) Suitability for liquid-gas ratio fluctuations. Plate towers are better than packed towers. Therefore, when liquid-gas ratio fluctuations are large, plate towers are suitable. (5) Operating flexibility. Plate towers are larger than packed towers, with float valve towers being the largest and bubble cap towers second. Generally speaking, cross-flow towers have smaller operating flexibility. c. Other reasons (1) In most cases, when the tower diameter is greater than 800mm, a plate tower is suitable, and when the tower diameter is less than 800mm, a packed tower is suitable. But there are exceptions. The use of Pall rings and some new packing materials in large towers can be better than that of plate towers. Similarly, when the tower diameter is less than 800mm, plate towers are also used. (2) Generally, packed towers are heavier than plate towers. (3) For large towers, plate towers are cheaper to build. Since the price of packing is approximately proportional to the volume of the tower, the price of plate towers is calculated based on unit area and decreases as the tower diameter increases.

Very detailed, thank you. Currently studying * design.

The diameter of a packed tower should generally not be too large, generally less than 2.5m is more reasonable, but the processing capacity is small. If it is larger, the side wall effect will be more serious; the diameter of the plate tower is generally not less than 0.65m, and above 2.5m, it can have a larger processing capacity and the overall efficiency is higher. The question you asked seems to be wrong. The choice of plate tower or packed tower depends on the comprehensive analysis of many factors, and cannot be analyzed from the tower diameter alone. The tower diameter is only one aspect.

Tower diameter is not the first condition for selecting trays or packing. It is generally determined based on the properties of the materials. In terms of normal use, if the tower diameter is too small, it is not convenient to use a plate tower for maintenance. If the tower diameter is too large, the side wall effect of the packing will be obvious. The smallest plate tower has a tray shape similar to a candied haws, with a tower diameter of about 350. The 10-million-ton decompression tower of a domestic crude oil decompression device also has a large inner diameter (not sure, probably about 7/8 meters), but the internal parts still use structured packing. Personally, I think the form of the internal parts is still determined by the nature of the material. When both are available, consider which one is more convenient for maintenance.