When simulating a vacuum distillation unit, the actual number of trays can be converted into theoretical trays using empirical efficiency; as for the feed position, how should it be determined...
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The literature I’ve read only gives brief overviews; so what is actually done in practice?
For example, in the case of batch feeding, you can select a theoretical plate whose liquid-phase composition is closest to that of the feed; this plate can then be used as the feed plate. Of course, with sophisticated tools like Aspen available, you can conduct a sensitivity analysis by using the position of the feed inlet as a variable and the concentration of the distillate phase as the response variable, in order to determine which plate is the most suitable.
Yes, sensitivity analysis can be used to determine the optimal feed plate, and there are existing examples to follow. But how should the interrupt cycle and the positions of the inlet and outlet of the stripping tower be set? I now know the actual structure of the atmospheric pressure tower, and I want to carry out a field simulation; unfortunately, I have no prior experience with such processes, which leads to various problems. I hope the moderator can provide some guidance – thank you very much
I’ve never done vacuum distillation before; it seems quite complex, but the principle should be similar. I’m not quite clear about the function of the intermediate cycle and the stripping tower you mentioned. Taking the side-stream output as an example, first run a simulation without any side-stream output, then examine the composition of each tray inside the tower, and select the desired side-stream concentration for the output; run another simulation. Of course, with side-stream output present, the results will be different, and adjustments can be made accordingly