A correlation of diffusion coefficient at infinite dilution based on dense fluid theory

In this paper a new correlation of the Schmidt number is proposed as a function of solvent molar volume and molecular weight for predicting binary molecular diffusion coefficients in reservoir fluids and self-diffusion coefficients of dense and liquid carbon dioxide. The feature of this new correlation is that the model is derived from the Chapman and Enskog theory as well as computer simulation results for self-diffusion coefficients of dense fluids. In the correlation from experimental data, the cubic simplified perturbed hard-chain equation of state has been used to predict the molar volumes of the solvent as well as the molecular parameters in the new correlation. The newly-developed semi-theoretical liquid viscosity model of Du and Guo has been used in predicting the viscosities of solvents. Extensive comparisons of the calculated and experimental diffusion data have been carried out to ensure that the new model is applicable for predicting the self- and binary diffusion coefficients, particularly for carbon dioxide-alkane and alkane-alkane systems.