Correlations allow calculation of density for petroleum fractions.

Correlations allow calculation of density

Two new equations that allow calculation of the density of petroleum fractions without the need of graphical data have been developed.

The equations have been found to be as accurate as the American Petroleum Institute nomograph, and more accurate than some other recently proposed correlations. The equations will also allow computer evaluation of fraction densities.

Data on density at specific temperatures are required daily in a variety of chemical engineering computations. Some of these computations involve: fluid flow, heat and mass transfer, pumping, mixing, estimates of other properties, and interconversions of volumetric and mass flow rates.

Although a number of graphical and mathematical methods have been published to suggest ways to estimate the density of petroleum fractions when no experimental data are available, most of them suffer from various shortcomings.

In their guide books, Blan and Davidson, 1 and kern2 show graphs which express the density of petroleum cuts as a function of temperature and API gravity only. While useful for rough estimations, these approaches …