Calculating Entropy & Enthalpy: SRK, Wilson, Antoine & Clausius-Clapeyron

[FoFi_Olli]

I would like to calculate the entropy or enthalpies (steam, specific and inner energy) using the SRK [suave-redlich-kwong] equation, the Wilson approximation and (if necessary) the Antoine equation. and the Clausius-Clapeyron equation for a mixture of 0.199 mol/l nitrogen and 0.811 mol/l carbon dioxide. The critical mixture parameters (critical point) as well as the enthalpies (specific, internal and evaporation) at 50 bar pressure and 150 bar pressure and at a constant 288.15 K are to be calculated in order to then form the difference to find out how much energy , preferably in the wet steam area, can be stored.

I am a little bit stuck. Now I try to find out which A-factors to use when (SRK, Wilson, ...). Is the a-factor of wilson only useable for mixtures and only for liquids?

 

[Chestermiller]

I would like to calculate the entropy or enthalpies (steam, specific and inner energy) using the SRK [suave-redlich-kwong] equation, the Wilson approximation and (if necessary) the Antoine equation. and the Clausius-Clapeyron equation for a mixture of 0.199 mol/l nitrogen and 0.811 mol/l carbon dioxide. The critical mixture parameters (critical point) as well as the enthalpies (specific, internal and evaporation) at 50 bar pressure and 150 bar pressure and at a constant 288.15 K are to be calculated in order to then form the difference to find out how much energy , preferably in the wet steam area, can be stored.

I am a little bit stuck. Now I try to find out which A-factors to use when (SRK, Wilson, ...). Is the a-factor of wilson only useable for mixtures and only for liquids?

Everything you want to do is discussed in detail in Ch. 14 of Smith and Van Ness, Introduction to Chemical Engineering Thermodynamics.

 

[FoFi_Olli]

I thank You a lot.
It had to come to that point, that I tried to figure out the right way with the CHat-GPT.
Do you mean CH. 13 of the eighth version?

I give the Examples 13.5 and 13.7 of the eighth edition a try. In table 13.7 we can see how far the enthalpy and entropy calculated with the R/K-Equation differs from the S/R/K-Equation.

It is a lot more difficult, but i have to do it with the SRK-Eq. and therefore:
Is it possible to start with the calculation of the critical point of the mixture VLE (example 13.7) to get the factors I need and then to continue like in example 13.5 to get the enthalpy of the mixture?
My aim is to calculate the latent energy stored from one pressure point of 50 bar to another pressure point of 150 bar.

And three less important last questions:
What is the Modified Raoult’s Law and what ist the Modified Henry's Law for? Are they still subkritical? Could the Modified Raoult’s Law possibly be a more easy solution or does it not fit the problems ?

 

[FoFi_Olli]

Everything you want to do is discussed in detail in Ch. 14 of Smith and Van Ness, Introduction to Chemical Engineering Thermodynamics.

Hello Mr. Chestermiller,

i would be very grateful if you could answer the questions, since i am still stuck in the calculation and especially in the order of the calculation steps :)

thanks in advance
Olli Meyer

 

[Chestermiller]

I thank You a lot.
It had to come to that point, that I tried to figure out the right way with the CHat-GPT.
Do you mean CH. 13 of the eighth version?

I give the Examples 13.5 and 13.7 of the eighth edition a try. In table 13.7 we can see how far the enthalpy and entropy calculated with the R/K-Equation differs from the S/R/K-Equation.

I have the 4th edition.

It is a lot more difficult, but i have to do it with the SRK-Eq. and therefore:
Is it possible to start with the calculation of the critical point of the mixture VLE (example 13.7) to get the factors I need and then to continue like in example 13.5 to get the enthalpy of the mixture?
My aim is to calculate the latent energy stored from one pressure point of 50 bar to another pressure point of 150 bar.

I'm not sure my examples In the 4th edition correspond to yours. 13.7 involves NaOH solutions, and 13.5 involves a LiCl solution.

And three less important last questions:
What is the Modified Raoult’s Law and what ist the Modified Henry's Law for? Are they still subkritical? Could the Modified Raoult’s Law possibly be a more easy solution or does it not fit the problems ?

Sections on this in 4th edition are in Chapter 12.

 

[FoFi_Olli]

I have the 4th edition.

I'm not sure my examples In the 4th edition correspond to yours. 13.7 involves NaOH solutions, and 13.5 involves a LiCl solution.

Sections on this in 4th edition are in Chapter 12.

Hello again,
I want to figure out which chapters you are refering to.
Can You please post a screenshot of the chapters or name the titels of the given and important chapters?!
Bellow is a screenshot of the 8th version.

have a nice day and thanks in advance
Olli Meyer