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Extension of the pitzer correlation for compressibility factor calculations
Author(s) -
Hsiao YuhJen,
Lu Benjamin C. Y.
Publication year - 1979
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.5450570116
Subject(s) - thermodynamics , compressibility , compressibility factor , pitzer equations , chemistry , physics , activity coefficient , aqueous solution
The three‐parameter generalized correlation of Pitzer et al (1955) for calculating the compressibility factor Z of normal fluids in the T r and P r regions of 0.8 ≦ T r ≦ 4.0 and 0 ≦ P r ≦ 9.0 has been extended to wider ranges, using the P‐V‐T data available in the literature for 53 compounds with a total number of data points about 15,000. The linear equation in ω proposed by Pitzer et al is found to be adequate. Values of Z (0) and Z (1) of the linear equation are presented in tabular forms at regular intervals of T r and P r in the region of 0.2 ≦ T r ≦ 5.0 and 0 ≦ p r ≦ 12.0. Quantum gases and highly polar compounds are not included in the correlation. In comparison, volumetric data for 15 compounds were used as the basis for the correlation of Pitzer et al, while 4 compounds were used by Lee and Kesler. The ω values covered in this work (–0.002 to 0.9065) is also wider than those used by Pitzer et al. (–0.002 to 0.352) and Lee and Kesler (0.0072 to 0.4902). The overall average absolute deviation between the calculated Z values obtained from the proposed correlation and the literature values for the 12 compounds tested by Lee and Kesler is 1.38%, which reduces to 1.07% if 1‐pentene is excluded in the comparison. The corresponding deviations obtained from the correlation of Lee and Kesler are 1.41% and 1.35% respectively. The proposed correlation also yields better results at ω = 0 than those obtained from earlier correlations.