QUOTE (Clayton @ Nov 6 2008, 12:06 AM)

Does anyone have any advice on how to converge a CDU. Any general advice would be helpful.
My main problem is when i add the kerosene stripper it doesn't converge.
Are there any specific variables i should use to specify the column. I dont have overflash liquid flows and i saw that is what was used in the Hysys example as one of them.
Also, should i fixed the reflux ratio??
Dear,
Once you add any side stripper to the main fractionator of the CDU you get 2 degrees of freedom which you need to specify. Once these active specifications you have given it should be an issue to get it converge. Whenever you are simulating CDU in Hsysy start the flowrate values with the small numbers then try to achive the actual flows of the pump arounds and side strippers products. Always have a rough material balance or the column split before running the column as this will you to identify that any of the active specification is not overriding the convergence of the simulation model. Hope this could help you a little.