A simplified method for calculating saturated liquid densities

Abstract

A simplification for the Nasrifar–Moshfeghian (NM) liquid density correlation has been developed. A replacement for the Mathias and Copeman temperature-dependent term with the original Soave–Redlich–Kwong equation of state (SRK EOS) temperature-dependent term has been done. This replacement has overcome the limitations in use for the original model due to the Mathias and Copeman vapor pressure-dependent parameters. The new correlation uses one characteristic parameter for each compound and suggests a value of zero for generalization purpose. The revised model has been tested for pure compounds liquid density prediction of different types including paraffins, cyclo-paraffins, olefins, diolefins, cyclic olefins, aromatics, ethers, liquefied inorganic gases and alcohols. The average absolute percent deviation for 76 compounds consisting of 2379 experimental data points was found to be 0.58%. The simplified method was then used to predict the saturated liquid density of multi-component systems. The average absolute percent deviation for 58 multi-component systems consisting of 978 experimental points was found to be 0.67%. Generalizing the correlation, by setting a value of zero for the characteristic parameter, gave average absolute percent deviation of 2.01% for the same pure compounds and 1.57% for the 58 multi-component systems. The accuracy of the simplified model has been compared with other correlations and equations of states.