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Calculating K Values

antoine saturated vapor pressure flash pseudo oil gas

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#1 shahad


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Posted 07 April 2021 - 08:59 PM

I want to do a flash calculation on a reflux drum with a known temperature and pressure, so first I need to calculate the svp using antoine coefficients to then get the K values. 


My issue is that I have hydrogen, h2s, methane, ethane and propane, and the antoine coefficents are out of the temperature range, so is there another way to calculate the K values?


Also, I have a range of pseudo components (NBP54-154) so can I assume it is hexane/pentane?

#2 breizh


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Posted 08 April 2021 - 12:35 AM


You may consider the calculator attached to support your work together with an excel sheet used to calculate a flash based on EOS (Peng Robinson) . You will find a way to get access to Ki's in the document.


On top of that you may consider this web application offered by Quest :

Other Thermodynamic Properties – Quest Consultants

Good luck,


#3 latexman


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Posted 08 April 2021 - 07:43 AM

Here is an ancient resource - https://en.wikipedia...ePriester_chart


It may not have all your components, but I wanted to point it out.  I suspect with Hydrogen you may have to utilize some Henry's Law data/method.

#4 SilverShaded


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Posted 14 April 2021 - 02:12 AM

For accurate results you really need to use a simualtor as there will be significant intreactions between those compounds.  The Heavier hydrocabons will for example sponge the lighter compounds to some extent so using pure component vapour pressure won't be very accurate and could lead to significant error.

Edited by SilverShaded, 14 April 2021 - 02:12 AM.

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