Issues related to the filler

According to my personal understanding, there should be some differences

I checked online and found that the theoretical number of plates for the CY700 is 8–10 plates per meter. So its HETP should be 100–125 mm, right? (HETP = packing height/theoretical number of plates). But why do some manufacturers report an HETP of 333–400 mm? If HETP is 333–400 mm, then the theoretical number of plates should be 2.5–3 plates per meter. Thank you; I’m waiting online

The efficiency of the packing is generally directly related to the liquid distribution effect; it is higher in towers with small diameters, while for those with larger diameters, a lower number of theoretical plates is typically assumed. Furthermore, different systems vary; the theoretical plate numbers typically provided are determined for standard systems (benzene, toluene), and they may differ for other systems. In general design, the lower limit is usually adopted; for a 700 filler, about 5 theoretical stages are used.

This post was last edited by Chuangxin Packing on 2010-5-11 at 13:30. The value of the plate equivalent height HETP is first related to the type of packing: different types of packing have different specific surface areas, which in turn affects the size of the gas-liquid mass transfer interface; moreover, different packing materials have varying abilities to distribute gas and liquid evenly, and the more uniform the distribution, the better the mass transfer efficiency. Generally, the plate equivalent height of structured packing is smaller than that of bulk packing, and the higher the grade of the structured packing, the smaller its plate equivalent height (for example, the HETP of Mellapak350Y is definitely lower than that of Mellapak250Y)； Secondly, the equivalent plate height of the packing is also related to factors such as the tower diameter and the performance of the distributor. Since the distribution effect is generally poorer in towers with larger diameters, the efficiency decreases slightly; poor performance of the distributor and redistributor will certainly affect the mass transfer efficiency of the packing ； Finally, when the same filler is used in different systems, the mass transfer efficiency varies as well (the HETP differs). For example, the 4mm metal θ-ring used in laboratory settings yields 15–16 theoretical plates per meter of filler in the benzene-toluene standard system with a 20mm distillation column; however, this figure is much lower in the acetic acid-water system. The reason for this is that film formation and renewal on the surface of the filler occur more slowly in the latter system, which affects the mass transfer efficiency. How many meters high is the packing equivalent to one theoretical plate: http://bbs.hcbbs.com/thread-335664-1-1.html

The plate height of HETP, as well as the theoretical number of theoretical plates, depend on the type of packing and the specific application system

There are general classifications based on form and specific surface area, all of which are determined through experiments; the experimental setups are as mentioned on the 4th floor. However, when applying them in different situations, experience still plays a role, just like in the case of plate efficiency