Why is a packed tower the preferred choice for the renovation of old factories? Please, moderators, do not delete it. Thank you

I’ve encountered this question too; I asked someone in process design, and she said it’s mainly measured by their differences, such as cost-effectiveness.

It is mainly because packed towers are relatively inexpensive. 1# yangjie007

The separation capacity and efficiency of the filler are used to maximize potential

It requires less space for installation and maintenance, and offers greater flexibility in packing operations

The filler has a high operational flexibility and low subsequent costs!

Then why did the new plant choose a plate tower?

I think the question itself is not precise; new plants can also use packed towers. The specific choice is certainly determined by material properties/separation requirements/economics; it cannot be generalized. The tower height is determined by the separation efficiency of the internals, while the tower diameter is determined by the vapor-liquid load. Generally speaking, the separation efficiency of packed towers is higher than that of plate towers, and their operational flexibility is greater than that of plate towers. In the case where only the internal components can be replaced without changing the tower structure, using packing for modification can achieve the goal of increasing capacity. Or, due to space constraints, by replacing it with a new tower, the filler can also handle a larger volume. This is perhaps the intended meaning of this question. But packing is relatively expensive, especially structured packing. I don’t understand either why a slab is used for new construction.

The new type of packed tower exhibits the following characteristics: ① High separation efficiency: This packing can be designed to have a large specific surface area, thereby increasing the number of theoretical plates per unit height. For example, the theoretical number of plates per meter height for wire mesh packing can exceed 10 ； ② Low pressure drop: Generally, even under high loads, the pressure drop of regularly packed materials remains relatively low, which is one of its significant advantages ； ③ High flux and operational flexibility: Since the structured packing allows for higher gas and liquid fluxes, the production capacity can generally be significantly increased compared to tray towers of the same diameter. It also allows the flux to vary over a wide range; the elastic ratio of the structured packing itself can be as high as 100, but in actual packed towers, the elastic ratio is primarily limited by the operational elasticity of the liquid distributor inside the tower ； ④ Low liquid holding capacity: The liquid holding capacity refers to the amount of liquid retained on the surface of the packing, inside the internals, or on the trays of the tower during normal operation; it varies as the operating load changes. For packed columns, the liquid holdup is generally less than 6%, while in plate columns it can be as high as 8–12%. ⑤ Low amplification effect: Unlike granular fillers, the efficiency of structured fillers decreases only slightly when used in large towers. Therefore, it can be said that packed towers, especially those with structured packing, have more advantages over tray towers. However, due to limitations such as the properties of the material being processed, packed towers cannot completely replace tray towers; moreover, their performance is not ideal under vacuum operating conditions. Currently, packed towers are the trend of the moment, with new types of structured packing emerging one after another; it is believed that all these issues will be resolved.

Hehehe, guys, you’re overanalyzing it. In my opinion, it’s just a test related to sex; there’s no need to take it so seriously