Issues regarding towers in Aspen Plus
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Recently, I encountered some issues while simulating a distillation column, and I wanted to use the DSTWU module for quick calculations. However, I found that this model allows only one feed stream, whereas the column model I am working on has three feed streams. I’m a beginner; I’ve only used the DSTWU module and the RADFRAC module. It seems that neither of these modules allows for the input of multiple materials. Could anyone please tell me how to input multiple feed materials using these two modules? Or sending an example would also work; I’m extremely grateful here! !
I checked again just now and found that radfrac allows multiple feed streams to be entered, but I don’t know how to set the parameters
Radfrac can have multiple feed streams, and for each feed stream it is necessary to enter the feed temperature, pressure, flow rate, composition, and feed location. The method of entry is the same as that for the first feed stream; simplified modules cannot have multiple feed streams
I know now, but there are some parameters that can’t be set, such as the number of plates. I tried setting it arbitrarily, but convergence doesn’t occur. Could someone upstairs share an example? Thanks
There is a lot of information available online about various methods for setting up towers; it is recommended that the original poster take a look.
The parameter settings must be determined based on the specific system in question. For example, regarding the number of trays, choosing a random value may not lead to a convergent result; it’s possible that the number of trays is insufficient. In such cases, it’s necessary to conduct trial calculations and adjust the parameter values until the desired results are achieved. Alternatively, a simplified design module can be used to estimate initial values, after which a more precise distillation module can be employed to make adjustments around these initial values, which speeds up the process. The reason for non-convergence could also be improper settings of other parameters. Check the hints provided in the calculation results to identify where the error lies, and make adjustments accordingly. It’s best to analyze the process as well, rather than adjusting parameters blindly
Hehe, what the person above said is really accurate. But with the simplified method, there’s only one material to be imported – how should that be done?
First, the simplified method can only estimate one feed stream; furthermore, if convergence is not achieved, the number of iterations can be adjusted by setting the ‘minimum iterations’ value in the convergence settings under the corresponding column； Secondly, it is possible to adjust the draw rate and reflux ratio; if the feed stream can be simplified to a binary system, an approximate calculation of the number of theoretical plates can be carried out using simpler methods first, along with the determination of the reflux ratio, after which all components can be taken into account using more precise methods for the calculation. Thirdly, it is necessary to check whether the thermodynamic methods chosen are appropriate. There are many examples available – some are included in the Aspen installation files, and there are also plenty in our forum. It is recommended that the original poster look for them in the community’s shared resources