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In this work, a new algorithm for polydisperse asphaltene modeling through application of continuous molecular thermodynamics is introduced. The Scott-Magat theory of polydisperse polymer solutions is applied at equilibrium condition and a necessary and sufficient condition is defined to minimize the Gibbs free energy relation. Three commonly used distribution functions were examined for characterization of asphaltenes, and experimental data reported in the literature is used to adjust parameters of the distribution functions. Among the three distribution functions, the fractal molecular weight distribution function which gives accurate results is selected. A new exponential binary interaction coefficient between asphaltene and crude oil is introduced. The solubility parameter, volume fraction of asphaltene, and the amount of asphaltenes precipitated are calculated through minimization of Gibbs free energy and phase equilibrium condition. It has been shown that the calculated results are in good agreement with experimental data.

The cavitation technique with the use of a proper hydrogen donor can be used to upgrade heavy oils, such as atmospheric and vacuum residues and lower the difficulties of their transportation and exploitation. On the other hand, the very high localized temperature experienced in collapsing bubbles may activate the dispersed metal nanoparticles, and therefore the cracking or hydrogenation reactions may be catalyzed through the cavitation process of heavy oils. This paper investigated numerically the formation of a vapour phase in the cavitation chamber of a home‐made laboratory hydrodynamic cavitation setup and also investigated the upgrading of a sample of heavy fuel oil in the presence of gasoline as a hydrogen donor and metal nanoparticles. The results indicated that adding 0.01 L/L gasoline to a 10‐min cavitational cracking process at 80 °C and atmospheric pressure can reduce the viscosity of heavy oil by about 20 %. In addition, the presence of iron nanoparticles can increase the rate of hydrogenation and/or cracking reactions in the heavy oil cavitational upgrading process (HCUP) in the presence of a hydrogen donor.

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In this study, a new cubic hard sphere equation of state (EOS) was developed from standard classical thermodynamics. The new equation is applied to calculate properties of fluids and vapor-liquid phase equilibrium calculations. The derived equation is a simplified expression of the hard sphere equation which yields satisfactory agreement with the molecular simulation of hard molecule data. The EOS is written in a cubic form by combining the derived repulsive hard spheres with Redlich-Kwong (RK) empirical attractive term. Satisfactory calculated results for the saturated properties of pure fluids for temperature ranges from 303 to 523 K and pressure ranges from 50 to 5000 psi are obtained. Simplicity and generality of this equation combined with reasonable accuracy makes it a useable EOS for almost all areas of equipment design for separation processes and production operations including refinery and petroleum reservoir industries. The accuracy of the predicted properties from the developed EOS are greater than of other commonly used two parameter cubic equations of state, RK and Pang-Robinson (PR).