Problem with investigate HCl removal column

[andrejkucma]

Please, apologize me, only fault due quick work . Here is the right fsd.

[hkooijman]

I think this is a rather strange request but here is maybe a clue to kick-start you column. I first removed the sidestream that did nothing. Then I switched to internal thermo as to be able to run the column in the column simulator ChemSep directly w/o having to run at the flowsheet. I switched to a Reflux Ratio (RR) of 0.4 (guessed) for the top while keeping the bottoms spec of 1e-5 HCl. I initialize the column using a bottoms flow-rate and RR spec. Guessing the right bottoms flow is very important as when it is too little the x-HCl in the bottom is too small for the column to converge to the large concentration specified... Since 130 mol/s is coming in I guess 125. Using 120 will already result in a column that doesn't converge. On the other hand using 130 also causes an infeasible specification as the MB and Equilibria cannot do that. I monitor the RR and the bottoms xHCl as to check on the convergence. When you run at the flowsheet level you might loose the column solution when you make too big a change. You then probably need to adapt the guess and reset the initialization from "Old results" back to "Automatic"

Harry

[andrejkucma]

thank you for navigating, column is solve nice! but the real problem its then probably else yet... its problem when the column is implemented into flowsheet, because, ever when top and bottom stream go in heat exchangers beetwen C201 and HCl removal column, flowsheet doesnt converge. to be right, problem is MB in some heatexchanger. For ex. in exhanger go 80tones/hour and escape 130... all other is working.

[jasper]

Probably a feed or product stream to a heat exchanger is a cut stream. In this case the heat exchanger is in mass balance only in case the flowsheet is converged.

You can verify the cut streams by setting the verbose level to "debug" (flowsheet settings), which will put the cut streams (and a lot of other information regarding the solution) in the log window under the flowsheet.

[andrejkucma]

thank. good idea, Mr jasper. Its pleasure to work with you! I like this program