3 replies to this topic

[AnbIran]

Hi every one, I'm modeling a naphtha fractionator column, I could solve it but solving the model is very unstable when I change the parameters to fine tune some variables it could not solve and even when I put the values which software has already solved model for me, it couldnot solve again.

 

anyone knows is there any specific adjustments to fix this problem?

[shvet1]

no, there is not

[Pilesar]

Your specifications may be too tight. There must be a way for the column to material balance given the specs and stages and components you supply or you will get no convergence. While it may be a problem with the convergence algorithm, the problem usually is in the user input. Make a tiny parameter adjustment and view which way the converged solution travels.Is a stream drying up? Is a duty heading to zero? Having a converged run is a great starting place since they are much easier to troubleshoot. Did you prepare the original model or using someone else's model? If an old model, then there may have been changes in the databases during a version upgrade.Try building a new simulation from scratch using the same inputs.

Edited by Pilesar, 30 June 2024 - 07:19 AM.

[AnbIran]

Your specifications may be too tight. There must be a way for the column to material balance given the specs and stages and components you supply or you will get no convergence. While it may be a problem with the convergence algorithm, the problem usually is in the user input. Make a tiny parameter adjustment and view which way the converged solution travels.Is a stream drying up? Is a duty heading to zero? Having a converged run is a great starting place since they are much easier to troubleshoot. Did you prepare the original model or using someone else's model? If an old model, then there may have been changes in the databases during a version upgrade.Try building a new simulation from scratch using the same inputs.

Thank you Pilesar, I defined the model in Petro-SIM and my problem was solved, it was ok in Petro-SIM.