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[Bluehat]

Dear all,

I wish to rigorously simulate the column reboiler in hysys but unfortunately the simulation does not converged.  Here is the status of my case:

 

1. column is simulated with reboiler represented as a heat exchanger and steam used as the heating medium on the tube side.

2. simulation converged with the default exchanger model "calculated by the column"

3. I wish to use the rigorous model for the reboiler so that I can specify the reboiler type and define the exchanger geometry.

4. Rigorous Shell&Tube heat exchanger model selected from the parameters tab

5. Reboiler (BKU) geometry was specified

6. Shell and tube side pressure drop were defined 

7. When solver was activated to run the simulation, the following message appears: column has too many design specifications.

8. In the column monitor page four specs were active but only three are required so the following 3 specs were selected active: reboiler heat balance, product spec at the top of column and exchanger (reboiler) heat duty. Degree of freedom =0

 

 

Observations when the simulation was run:

1. Hot fluid allocation was changed to the shell side and can not be modified and the message displayed in the message tab reads "The data input for hot fluid location is unacceptable "

2. Not solved.

 

Will appreciate suggestions on how to converge the simulation.

 

Thank you

 

 

 

[Bobby Strain]

It is a great waste of time to attempt rigorous modelling as you propose. You can, of course, specify a circulation rate as part of the column operation if you are using a thermosyphon. Then, simply export the column streams to a rigorous model for heat exchange. This makes the exercise quite simple. That's what engineers do. Make the difficult task simple.

 

Bobby