Aspen empty tower spray simulation
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Hello, everyone: I am currently simulating gas absorption and purification in an empty tower (that is, a tower without trays or packing), which involves processes such as heat transfer and dissolution; therefore, Radfrac was chosen for this simulation. I’m encountering some issues now: in Aspen, if one wants to perform calculations based on flow rate or tower sizing, it’s necessary to choose between tray towers or packed towers; there seems to be no option for empty towers (if there is one I haven’t found it yet, please let me know). I also searched for relevant keywords on the forum and found that there is very little interest in tower top spraying. Some people suggest using CFD software, but due to the need to take into account the property parameters of various substances, it is generally very difficult to carry out physical-mechanical simulations using CFD. I would like to ask everyone here mainly how to calculate the HETP for tray spray, or how to calculate the mass transfer coefficient in tray spray. Thank you all~
Aspen does not provide a model for empty tower spraying.
Why is this? The F.R.I. rating software also does not have a blank tower spray module. . .
There’s no need to worry; a tower with spray nozzles is also a type of absorption tower. Choosing Radfraci is the right decision – it’s just that the parameter settings are different, resulting in an equivalent transition.
Well, it’s just an absorption/desorption process; using radfrac, simulation works fine for now. I now want to conduct theoretical calculations for the tower size; I’m currently stuck on calculating the HETP for an empty tower. Do any experts have any suggestions regarding this HETP or size calculation? Thanks, haha~
HETP is related to the tower diameter; with a tower diameter of DN1200 as the boundary, HETP is generally set at 600 mm, and the pressure drop under empty conditions is considered zero. The efficiency can be determined arbitrarily.
Thank you for your reply. Does that mean I can’t obtain this data directly in Aspen? (Because if calculations are done for a packed tower, HETP can be calculated directly, from which the tower height can be determined.) Additionally, HETP seems to be closely related to the mass transfer efficiency (I’m an amateur; that’s what I’ve understood after reading some books). So I feel that it’s necessary to first know (or calculate) the overall mass transfer coefficient, so that HETP can be calculated manually; however, the overall mass transfer coefficient for spray towers seems to also not be available for calculation in Aspen. .
Hello, OP; I’m stuck here as well. May I ask what simulation was used for the RadFra you selected in Aspen in the end? (Plate tower or packed tower?) Could the settings be expanded a bit? (Our current idea is that we have 13 theoretical series; when conducting simulations, we use these 13 series. We choose a packed tower, and when checking the packing, we only simulate levels 1-3. We’re not sure if this setup is correct.) Please help us out, OP
Same question, mine has a 7-layer spray system. How to set the feeding position? If it’s convenient, add me on QQ at 1242435638