3 replies to this topic

[JOAN93]

Hello all! I am a student working on a simulation of a dehydrogenation column of propane to get propene. 

I'm using Aspen V8.4 we get the next error when we ran the column. 

 

SEVERE ERROR

   THE FOLLOWING STAGES DRIED UP (VAPOR OR LIQUID FLOW APPROACHES 0):

     1    2    3    4    5    6    7    8    9   10   11   12   13   14

5  16   17   18   19   20   21   22   23   24   25   26   27   28

9  30   31   32   33   34   35   36   37   38   39   40   41   42

3  44   45   46   47   48   49   50   51   52   53   54   55   56

7  58   59   60   61   62   63   64   65   66   67   68   69   70

   A LIMIT OF  0.10000E-04 * SUM OF FEEDS WAS IMPOSED ON THE FLOW RATES

   OR A LIMIT OF  0.10000E-04 WAS IMPOSED ON THE STAGE V/L OR L/V RATIO

 

I have no idea on how to solve this issue. Could anyone please help me? 

 

I leave you guys a dropbox link here so if anyone of you guys can access to the program maybe that might help! 

 

https://www.dropbox....ion 1.apwz?dl=0

 

Thanks ahead!

 

 

[Bobby Strain]

Well, you must first convert propane to propylene in a reactor.

 

Bobby

[JOAN93]

Our feed data it's provided by the company that designed the project, so we're not supposed to deal with  the reaction. We are just supposed to simulate the separation and once simulation is successful then add a new feed stream and optymize it's feed stage. 

[Pilesar]

Every stage must have vapor and liquid. Do you have condenser at the top and reboiler at the bottom? Errors like "tray drying up" often indicate that the specifications are impossible to meet. Change your specs so that you will get convergence. If you cannot figure out where your specs are impossible, choose something simple like a bottoms flow rate and reflux ratio. Once you get convergence, then review results and modify your specs gradually till you understand how the model behaves. Save your work often as a new file name so that you can revert to an older working model if you fall into a pit.