PROII simulation for atmospheric and vacuum distillation: the last side stream column does not converge; seeking advice from experts

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This post was last edited by wode1986053 on 2017-5-9 at 11:06. A beginner is working with the Pro II simulation; a constant-pressure column model has been added on top of the models used previously. There are five side streams in total. For the first four columns, the extraction amounts and the corresponding extraction amounts from the main column were set as variables. After multiple runs, convergence was finally achieved. However, when the last side-stream column was added, the following error message kept appearing: ** A FATAL ERROR OCCURRED ON ITERATION 2 *** ERROR HISTORY IS NOT AVAILABLE FOR THIS ITERATION *** ERROR *** UNIT 12 - TEMPERATURE EXCEEDS LIMIT on tray 45. *** ERROR *** UNIT 12 - WATER SUPERSATURATION DETECTED on 1 trays. Column solution is likely to be erroneous. Rerun using the SURE column with the FREEWATER (DECANT) option enabled. UNIT 12 NOT SOLVED *** PROBLEM SOLUTION NOT REACHED ** WARNING ** Unit ‘12’ DID NOT SOLVE *** Run completed - Case not solved. Images cannot be added :'( The model also cannot be uploaded due to company network restrictions:Q