Ponchon Savarit for distillation + overall efficiency?

In summary, you can apply efficiencies on the Ponchon-Savarit diagram by shifting the diagonal line that separates the two liquid-vapor equilibrium curves. Efficiencies can also be applied to the enthalpy curves by shifting them up or down. There is no basic step-by-step guide, but this information should help with understanding the process.
  • #1
maistral
240
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I'm having trouble trying to figure this out.

I am aware how to employ overall efficiencies on McCabe-Thiele - IIRC it goes like:

"draw a pseudoequilibrium curve in between the equilibrium line, and the rectifying/stripping lines - 100% efficiency means that it coincides with the equlibrium line, 50% efficiency means it lies directly in between the EL and RL/SL, and 0% efficiency means that the pseudoequilibrium line concides with the RL/SL"

I don't know how to employ efficiencies on the Ponchon-Savarit though. Do I still do this mechanic with the diagonal line? What about the enthalpy curves?

is there a basic step-by-step guide in doing this? Thanks!
 
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  • #2
Yes, you can still employ efficiencies on the Ponchon-Savarit diagram. The efficiency will be applied to the diagonal line that separates the two liquid-vapor equilibrium curves. Depending on the efficiency, the diagonal line will be shifted up or down. A higher efficiency will mean the diagonal line is shifted up, whereas a lower efficiency will mean the diagonal line is shifted down. You can also apply efficiencies to the enthalpy curves. A higher efficiency will mean the enthalpy curves are shifted up, whereas a lower efficiency will mean the enthalpy curves are shifted down. Hope this helps!
 

1. What is Ponchon Savarit for distillation?

Ponchon Savarit is a graphical method used to analyze and design distillation columns. It allows for the determination of the number of theoretical stages required for a given separation and the overall efficiency of the column.

2. How does Ponchon Savarit method work?

The Ponchon Savarit method involves drawing a diagram with two vertical axes representing the vapor and liquid compositions, and a horizontal axis representing the number of theoretical stages. By plotting the equilibrium curve and operating line on this diagram, the number of theoretical stages and overall efficiency can be determined.

3. What are the benefits of using Ponchon Savarit for distillation?

Using Ponchon Savarit allows for a quick and accurate analysis of distillation columns, helping to optimize their design and operation. It also allows for a better understanding of the separation process and can help identify potential issues or areas for improvement.

4. What are the limitations of Ponchon Savarit method?

One limitation of the Ponchon Savarit method is that it assumes ideal behavior of the components in the distillation process. In reality, there may be non-idealities such as azeotropes or deviations from Raoult's law, which can affect the accuracy of the results.

5. How is overall efficiency calculated using Ponchon Savarit method?

The overall efficiency of a distillation column is calculated by dividing the actual number of stages required for the separation by the minimum number of stages predicted by the Ponchon Savarit method. This ratio is then multiplied by 100 to give a percentage value for the overall efficiency.

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