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Modified van der waals equation for the dense gaseous and liquid regions from PVT data for methane
Author(s) -
Dingrani J. G.,
Thodos George
Publication year - 1975
Publication title -
the canadian journal of chemical engineering
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.404
H-Index - 67
eISSN - 1939-019X
pISSN - 0008-4034
DOI - 10.1002/cjce.5450530313
Subject(s) - methane , dimensionless quantity , thermodynamics , van der waals force , equation of state , compressibility , theorem of corresponding states , van der waals equation , compressibility factor , neon , absolute deviation , chemistry , reduced properties , van der waals radius , physics , argon , organic chemistry , molecule , statistics , mathematics
PVT measurements available in the literature for methane in the gaseous and liquid regions were used with the van der Waals equation of state,\documentclass[article]\pagestyle[empty]\begin[document]$$ \left( [P + \frac[a][[v^2 ]]] \right)\left( [v - b] \right) = RT $$\end[document]to obtain values of the internal pressure parameter, a , where the covolume parameter was taken as b = v c /3. The conditions covered temperatures from 114.53°K (T R = 0.599) to 611°K (T R = 3.20) and pressures up to 3000 atm (P R = 65.50). A dimensionless relationship was developed for the dependence of the parameter a on density and temperature for the gaseous and liquid regions. Density values for methane were calculated from the resulting equation and were compared with the corresponding experimental values to produce an average deviation of 0.26% (791 points). This relationship also enabled the accurate prediction of density values for substances having similar critical compressibility factors as methane (z c = 0.289). For neon and ammonia, this relationship was found to have a limited applicability.