New equations for enthalpy of vaporization from the triple point to the critical point

1988 ◽  
Vol 9 (4) ◽  
pp. 567-575 ◽  
Author(s):  
G. R. Somayajulu
Keyword(s):  
Critical Point ◽  
Triple Point ◽  
Enthalpy Of Vaporization

scholarly journals Corollary from the Exact Expression for Enthalpy of Vaporization

2011 ◽  
Vol 2011 ◽  
pp. 1-7
Author(s):  
A. A. Sobko
Keyword(s):  
Critical Point ◽  
Thermodynamic Parameters ◽  
Exact Expression ◽  
Enthalpy Of Vaporization ◽  
Atoms And Molecules ◽  
Linear Dimensions ◽  
Accuracy Of Measurements

A problem on determining effective volumes for atoms and molecules becomes actual due to rapidly developing nanotechnologies. In the present study an exact expression for enthalpy of vaporization is obtained, from which an exact expression is derived for effective volumes of atoms and molecules, and under certain assumptions on the form of an atom (molecule) it is possible to find their linear dimensions. The accuracy is only determined by the accuracy of measurements of thermodynamic parameters at the critical point.

Three-parameter correlation for the surface tension of saturated liquids

2020 ◽  
Vol 34 (11) ◽  
pp. 2050107 ◽  
Author(s):  
Qiuju Chen ◽  
Jianxiang Tian ◽  
Hua Jiang
Keyword(s):  
Surface Tension ◽  
Critical Point ◽  
Triple Point ◽  
High Accuracy ◽  
Economic Benefits ◽  
Operating Conditions ◽  
Simple Liquids ◽  
Parameter Correlation ◽  
Multiple Parameter ◽  
Better Than

In this paper, we study the multiple-parameter correlations for the surface tension of saturated liquids. The proposed three-parameter correlation requires only the critical temperature as inputs and is tested by using the NIST REFPROP data for 72 saturated liquids including refrigerants, alkanes and some other simple liquids such as argon, carbon dioxide, etc. It is found that this correlation well stands in the whole temperature range from the triple point to the critical point with high accuracy for 71 liquids with average absolute deviations (AADs) less than 5% and for 66 liquids with AADs less than 1%. These results are clearly better than the ones of other available correlations. This correlation can be directly used to estimate the value of the surface tension of the corresponding liquids at any temperature point from the triple point to the critical point. The accuracy of the predictions would clearly have economic benefits since it would allow improvement of process operating conditions, the development of new processes, the reduction of oversizing in the design of new equipment and even reduction of energy requirements.

THE TEMPERATURE DEPENDENT ENTHALPY OF VAPORIZATION OF PURE SUBSTANCES

2008 ◽  
Vol 22 (25) ◽  
pp. 2509-2515 ◽  
Author(s):  
JIANXIANG TIAN
Keyword(s):  
Triple Point ◽  
B Value ◽  
Coexistence Curve ◽  
Enthalpy Of Vaporization ◽  
Temperature Dependent ◽  
Absolute Deviation ◽  
Quantum Fluid ◽  
Theory Result ◽  
Pure Substances ◽  
Better Than

Recently the universal behavior of the temperature dependent enthalpy of vaporization along with the whole liquid–vapor coexistence curve at equilibrium is described and explained by Roman et al.5 The work (called RWVM relation) succeeds in the combination of the linear relation near the triple point and the renormalization group theory result near the critical point. For the convenience of chemical designs and engineering applications, we report its b values yielding the minimum average absolute deviation (AAD) for 74 pure substances from the NIST web-book and compare the results with other correlations. We find that with an adapted b value, the RWVM relation predicts the data of 47 pure substances with an AAD less than 0.0093, with six more than 0.02 and all less than 0.03 except quantum fluid hydrogen, that is clearly better than other correlations. For most pure substances, b covers the range from 0 to 1. Only one negative value stands for the quantum fluid helium because of its enthalpy of vaporization being experimentally not a monotonic function of the temperature in the range near the triple point.

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