7 replies to this topic

[Bal]

Hello, 

 

I've a problem in converging the attached reboiled absorber and will appreciate your help in that.. I want the convergence of this column to be robust.. Is it impossible??

 

The only specification it has is related to the ratio between c1 and c2 in the bottom liquid prodctt (0.02)

 

Thanks

 

Attached Files

•  reboiled absorber.zip   105.25KB   10 downloads

[Bobby Strain]

If you don't succeed, model it as a distillation operation.

 

Bobby

[Bal]

I'll try it.. and let you know 

Thanks

[Bal]

Same problem with the column..

I tried to change the solver to Modified HYSIM Inside-Out and the convergence improved.. Is it bad to use this solver???

[Bobby Strain]

I would not use the solver. Try less strict specifications until it converges. Or, change specifications to maybe overhead product flow. You need to set up feed at least one stage below the top tray.  and set the reflux at some nominal value until it converges. then change to the specs you want. Then reduce reflux flow until it is near zero. Just try different things until it converges. Have patience.

 

Bobby

[Bal]

You mean that I should relax the absolute and weighted tolerance?

 

what about the heat and the equi. errors?

 

Also, when the column fails to diverge, I look at the temperature profile and it's totally bad...

 

Could you have a look at the file I have attached? 

[Bobby Strain]

What you should try is something different. For example, specify the overhead product flow and reflux flow. Adjust one or both until you get a converged solution. Then move from that point.

 

Bobby

[Bal]

I will try it in a while