Please explain what you mean by “deviation rate of state equation” and “enthalpy change deviation rate”. Deviation from what? At which thermodynamic state?

The gas here is propane, 300K, 0.99MPa.

Compression rate is calculated by empirical equation: Z = PV / RT.

Compression rate deviation rate: η=(Z-Znist)/Znist,

Znist - the result of NIST.

Here only the empirical equation of state (EOS) calculation results of value η=-0.01~+0.01 are selected.

Corresponding enthalpy change H1 = H-H0

H - Enthalpy of Real Gas H0 - Enthalpy of Rare Gas

H1 derived from the empirical equation of state above by the second law of thermodynamics

Enthalpy deviation rate: η=(H1-H1 nist)/nist,

H1nist --- The result of NIST.

Compression rate only reflects the accuracy of the equation of state. The enthalpy deviation rate calculated by empirical equation of state with deviation rate_=-0.01~+0.01 is about 14.6%.

This is caused by the inaccuracy of the second law of thermodynamics. This is a common phenomenon, which is known to all who engage in thermophysical activities.

Literature screenshots are from “Properties of Gases and Liquids”.

“Compression rate deviation rate”? I should call this “relative deviation of the compression factor”.

Znist is presumably the result of the NIST reference correlation. What is Z?

Please also explain what the diagram shows! “Output vs. input of the Second Law” is incomprehensible. The Second Law is neither a computer nor a machine; it cannot have input or output. Please state your problem more clearly.

Z is the compression factor, no mistake.

Z is very accurate and the equation of state is very accurate.

Enthalpy can be calculated by the equation of state and the second law of thermodynamics.

The equation of state is very accurate, the accuracy of enthalpy calculation is wrong, the problem lies in the second law of thermodynamics.

报错

(1) I understand that ZNIST is the compression factor of propane, obtained from the NIST reference correlation.

I understand from your first message that you observed a deviation (Z–ZNIST)/ZNIST.

How did you calculate Z?

(2) I understand that you observe a difference (14.6%) of the enthalpy values from two different sources.

Please explain what you mean by “enthalpy”! There are residual and total enthalpies; the latter are differences with respect to some standard state, and the standard state may not be the same between different tabulations. For example, chemists assume that the molar enthalpy of pure chemical elements at 1 bar, 298.15 K is zero. This allows them to estimate the heat of chemical reactions. Engineers sometimes assume that the enthalpy of pure components under standard conditions is zero. Furthermore, the standard state has not always been the same over the past 100 years.

Compression coefficients are derived from a variety of empirical equations (such as the RK equation, which you can see on the left side of the picture).

The calculation here is not enthalpy, but enthalpy change (Hd = H (300K, 0.99Mpa) - H (300, 0Mpa).

Nist's results are close to the experimental results.

“Nist's results are close to the experimental results.“

Yes, this is what reference correlations are for.

Now, what is the problem? You still have not explained what the diagram shows, nor stated your question in a way that others can understand it.

1. This involves the quantitative calculation of the second law of thermodynamics. The input is the equation of state. The deviation rate of compressibility (-1%~1%) indicates that the empirical equation of state has a good accuracy.

2. The enthalpy deviation rate derived from the equation of state with high accuracy (deviation rate=-1%~1%) is very high.

3. High-precision input leads to poor-precision output. This is the result of theory. Or the second law of thermodynamics lacks the ability of quantitative prediction.

You need to know, how does the second law of thermodynamics come into being? It simplifies and filters molecular interactions. It is normal to have a high theoretical deviation rate.

* * * * *

The starting point of thermodynamic logic is: 1) opposing perpetual motion. 2) The irreversibility of dynamics. Let's look at how to get Carnot efficiency = 1-T1/T2.

1.1 There are many kinds of type 2 perpetual motors, each of which is a natural phenomenon.

A) Machine A: against the irreversibility of thermodynamics (diffusion, heat conduction, friction, etc) - dynamics;

B) Machine B: Utilizing the Difference of Carnot Efficiency (Reversible Thermodynamics) - Thermodynamics

1.2 A and B belong to different disciplines. There is a parallel relationship between them and there is no logical mutual inevitability.

1.3. Logic of the Second Law of Thermodynamics:

Experience induction, deny that A machine==> B machine can not be manufactured==> All material Kano efficiency: 1-T1/T2.

1.4 The logic of the second law of thermodynamics violates the physical logic that A and B cannot be inferred from each other.

1.5 The second law of thermodynamics elevates the "irreversibility", which is in fact only a kinetic experience.

📷 Detailed discussion can be found in the following figure.

1. The second law of thermodynamics loses the ability of quantitative prediction.

2. Data processing method of law 2 of thermodynamics violates scientific discipline: modifying experimental data to satisfy theory

See the picture for details.

3. The second law of thermodynamics can only be called science if it reaches the same quantitative prediction ability as Newton's second law, otherwise it is pseudoscience.

4.Unfortunately, all the charts of enthalpy and entropy are organized in this way.

Sorry, but Fig. 1 is nonsense. One cannot predict the 2nd virial coefficient from the 2nd Law. It is necessary to have some experimental data or a pair potential.

P(V, T, E) is not a meaningful expression for a pure fluid. There can only be two independent arguments.

From the references, NIST gas thermophysical properties data are arranged by the second law of thermodynamics (Wagner method).

1. Only experimental data (PVT) are needed to fit the equation of state.

2. The second law of thermodynamics: fitting equation of state requires experimental data (PVT+E)

3. I use the equation of state (PVT) of carbon dioxide output from NIST (sorted out by the second law of thermodynamics) to inversely derive the 2nd virial coefficient.

4. Another NIST scientist obtained the 2nd virial coefficient of carbon dioxide from experiments. The difference between the two is shown in the figure.

5. Which do you believe in different 2nd virial coefficients?

Fig. 1 is for carbon monoxide, not carbon dioxide.

The empirical equation of state published by NIST, a function of the Wagner–Span type published by Lemmon and Span, is not a reference correlation. The 2nd virial coefficient derived from this correlation matches the experimental points reasonably well; the solid curve in the diagram is wrong.

Comparison of New and Old Thermodynamics

1. Logic of the Second Law of Thermodynamics: Subjectivism, Logical Jump, Interdisciplinary Argumentation.

2. New thermodynamics pursues universality, two theoretical cornerstones:

2.1 Boltzmann formula: ro=A*exp(-Mgh/RT) - Isotope centrifugal separation experiments show that it is suitable for gases and liquids.

2.2. Hydrostatic equilibrium: applicable to gases and liquids.

3. The second and third sonic virial coefficients of R143a derived from the new thermodynamics are in agreement with the experimental results.

3.1. The third velocity Virial coefficient derived is in agreement with the experimental data, which shows that the theory is still correct when the critical density is reached.

4. See Appendix Pictures and Documents for details.

The contradiction of the second law of thermodynamics