Absorber

[aken]

Hi.
Was wondering, is there a way to do a parametric stud of solvent flow rate versus recovery of a component in the absorber. Asking because recovery is not one of the option is there a way around this?

[jasper]

What do you mean by recovery? If you mean the relative amount going over the top or bottom, you could use measure units to measure the compound flow rates (in and out) and an information calculator to calculate the recovery.

[aken]

Thank you. I varied the solvent flow rate for the absorber, so as to obtain the flow rate to achieve the desired specification while holding number of stages constant. I then wanted to to hold constant the optimized solvent flow rate, so as to optimize the number of stages. But if l do that the only stages suitable is the one l held constant while optimizing the solvent flowrate. My question is there any way to optimize this together?

[jasper]

Not clear on your question again. Unfortunately COFE does not (yet) have an optimizer. But you can vary solvent flow rate and feed stage together. You'd get a matrix of answers, which you can plot. You would need to first export feed stage as a input parameter from ChemSep.

[aken]

Trying out the procedure from this paper where water is the solvent

https://www.owlnet.rice.edu/~ceng403/gr ... dillo.html
So if l vary number of stages in COFE, does it automatically switch the feed stages to the first and last stage in an absorber?

[hkooijman]

You should consider running parametric studies inside ChemSep. To do so, open up the column and go to the cape-open panel. First switch off Cape-Open properties. This will allow you to run parametric studies on the column. Then define your thermo again. Once you defined that, you can solve inside the ChemSep User Interface and also get Analysis tools. First Solve the column again - checking that your results remain the same - and then use Analysis / Parametric study. Select your input parameters, in your case the number of stages as well as the bottom feed stage. Make sure you vary both in the same way. Then select output variables, for example concentrations in the products or flow rates. Run and you can see the influence of the number of stages in your column.

[aken]

Thank for your responses, really helped. I have a question about the the measuring unit, l assigned it to measure 5 flow rates, and in ports it shows l can connect 5 outputs, but l can not connect the 5 information streams. This is because l want to calculate recovery for 5 components and l following the chemsep example. See attached, thanks

[jasper]

This is because the icon only has 4 connection points. Either change the icon, or just remove the icon. The latter will give you a box, where you can connect anything to any side.

[jasper]

(when you try to connect, a warning message along these lines should show up in the log?)