Modified Estimation of Oils Density

Tyumen State University Herald. Physical and Mathematical Modeling. Oil, Gas, Energy


2016, Vol. 2. №3

Modified Estimation of Oils Density

About the author:

Aleksandr A. Moiseev, Cand. Sci. (Tech.), Senior Research Associate, State Research Institute of Chemmotology (Moscow);


Significant attention is paid to the construction of the approximation describing liquid and solid hydrocarbon state at various temperatures and pressures. The natural basis for such approximation is the law of corresponding states of van der Waals. According to it, all the substances are subjected to the same equation of state, if this equation is expressed in terms of the reduced variables. This law is approximate and allows you to evaluate the properties of a dense gas or liquid in a simple way. The calculations employs the Mendeleev–Clapeyron equation supplemented with the compressibility factor characterizing the deviation of the studied hydrocarbon parameters from the state of the ideal gas with the same molecular weight.

In terms of this approach there have been built modified hydrocarbon density estimation algorithms based on the use of the law of corresponding states. In contrast to the traditional algorithm based on the use of correlation tables, the modified algorithms use the idea of compressibility factor in the form of a power function reduced temperature and pressure. The parameters of this presentation are calibrated by least squares method based on the comparison results for the calculated and tabulated values of alkanes densities under normal conditions.

The article shows that the modified algorithms provide better accuracy for light alkanes, and they can be used in combination with traditional algorithm for accurate density estimation of a wide range of hydrocarbons.


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