5 replies to this topic

[abolghasem202]

Dear all,

 

 

I am simulating a distillation  column using HYSYS. 

The problem is that my simulation results are identical to plant data, when I set tray murphree efficiency to 93%. Therefore, I dont know if my simulation is correct or I have made a mistake.

The column contain sieve trays with weir height of 64mm.

Is it possible that sieve trays provide such a high murphree efficiency?

 

I would appreciate your suggestions.

[Bobby Strain]

I always use ideal stages for simulation. It's less complicated than using efficiency. The efficiency of any tray depends on the components, too, and there are many publications that you can refer to. If you tell us the separation you are simulating you may get some help. I'm not sure why you doubt your simulation if it matches your actual performance. That's what we all strive for.

 

Bobby

Edited by Bobby Strain, 05 February 2019 - 04:11 PM.

[abolghasem202]

Bobby,

 

Thank you so much for your response.

 

The column is used for separation of propene/propane mixture.

 

The reason that I doubt my simulation is that when I set murphree efficiency to a typical value (~60%), the products purity deviate about 0.5% from the plant data. Im not sure that sieve trays can provide efficiency of 93%. 

 

My concern is that the actual efficiency of trays might be around 60% and the 0.5% difference in products purity can be due to something else that I can not see in my simulation.

[Bobby Strain]

In this service tray efficiency (Theoretical/Actual) is near 100%.

 

Bobby

[breizh]

Hi,

You may find some interest reading this paper.

 

http://www.ijcea.org/vol8/621-A726.pdf

 

good  luck

 

Breizh

[Technical Bard]

In a C3 splitter column, especially larger diameter ones, I have actually seen plant data with tray efficiencies above 100% because there are horizontal gradients in the composition across the tray deck.  But that is rare. 

 

Look up the O'Connell curves in Kister's Distillation Design book.