Improved correlations for heavy n-paraffin physical properties

Critical properties and acentric factors are essential input parameters for equation-of-state models. Experimental data for such properties are limited for heavy hydrocarbons; this necessitates the use of property correlations based on data for lighter members of the homologous series under study. However, inaccurate estimates of the critical properties and the acentric factors often translate to erroneous phase behavior predictions and computational failures. experimental measurements extend the available data on critical properties of n-paraffins up to n-C36; using this information, we have examined a number of existing correlations for predicting n-paraffin physical properties. Careful evaluation of the quality and the extrapolation capability of each correlation indicates that the asymptotic behavior correlation (ABC) is well suited for the task. Accordingly, we have updated the ABC using the recent experimental data. The accuracy of the updated correlations for describing experimental critical temperature, critical pressure, acentric factor, critical compressibility, and normal boiling point temperature for normal paraffins is 0.2, 0.8, 0.4, 0.6, and 0.1%, respectively, over the range from C3 to n-C36.