Evaluation of material property estimating methods for n-alkanes, 1-alcohols, and methyl esters for droplet evaporation calculations

Modeling of heat and mass transfer in liquid fuel combustion requires several material properties in a wide temperature and pressure range. The unavailable data are commonly patched with various estimation methods. In this paper, group contribution methods (GCM) and law of corresponding states (LCS) were analyzed for estimating material properties of n-alkanes (up to C10H22 and C12H26), 1-alcohols (up to C10H22O), and methyl esters (up to C19H38O2 and C19H36O2). These were compared to reference data to evaluate their applicability. LCS suggested by Poling et al. provides proper estimation for the acentric factor. GCM of Joback accurately estimates normal boiling point, critical properties, and specific heat capacity of the vapor-phase, the latter was corrected for methanol, however, GCM of Constantinou is more accurate for critical pressure of methyl esters. GCM of Ruzicka is suitable for estimating liquid-phase specific heat capacity. This method was updated for methanol. GCM of Elbro gives a proper estimation for liquid-phase density, while LCS of Lucas estimates vapor-phase viscosity properly. LCS of Chung and the modified Eucken method for vapor-phase and GCM of Sastri for liquid-phase thermal conductivity are appropriate. Considering the gas-phase mutual diffusion coefficient, the method of Fuller provides the best estimation, while LCS methods of Riedel and Chen are suitable for the enthalpy of vaporization at the normal boiling point.

Characterization of Pure and Undefined Petroleum Fractions of Messla and Sarir Crude Oils of Libya Using Correlation Models

<p>Knowing the physical properties of hydrocarbons and petroleum fractions is essential for designing most crude oil production and refining processes. Several correlations, called group contribution methods, have been proposed in the literature to assess these parameters and have been used extensively. The majority frequent correlations reported in the literature, where it is generally accepted in the petroleum industry, are used to describe unspecified fractions of oil. The only input parameters required are specific gravity and normal boiling point or molecular weight. Calculated properties include: normal boiling point (T_b), Molecular weight (Mw), critical properties for instance critical pressure (P_c), critical temperature (T_c), critical volume (V_c) and acentric factor (ω), as well as other parameters including Watson factor (K), and compressibility factor (Z_c). In this approach, x samples of petroleum fractions of Messla and Sarir crude oils of Arabian Gulf Oil Company, Libya have been collected. A quantity of characterization technique of untainted and unknown petroleum fractions have been presented to foresee the physical properties of these petroleum fractions. Correlations for characterizing non-specific petroleum fractions suppose precise seriousness and boiling point as input parameters. These correlations are Twu Correlations, Cavett Correlations, Kesler-Lee Correlations and Riazi-Daubert Correlations. The physical properties of the compounds in terms of specific gravity and (T_b) were shown on the algorithm and the correlation models for the auxiliary acids were corrected in this study. The considerations addressed revealed that there is no significant difference between the correlation models and the results obtained and it appears to be very close to the similar published data of the cited authors.</p>

A Re-assessment of the Thermodynamic Properties of Osmium

The thermodynamic properties were reviewed by the author in 1995. A new assessment of the enthalpy of fusion at 68.0 ± 1.7 kJ mol-1 leads to a revision of the thermodynamic properties of the liquid phase and although the enthalpy of sublimation at 298.15 K is retained as 788 ± 4 kJ mol-1 the normal boiling point is revised to 5565 K at one atmosphere pressure.

Song and Mason Equation of State for Refrigerants

In this work, the Song and Mason equation of state has been applied to calculate the <em>PVT</em> properties of refrigerants. The equation of state is based on the statistical-mechanical perturbation theory of hard convex bodies. The theory has considerable predictive power, since it permits the construction of the <em>PVT</em> surface from the normal boiling temperature and the liquid density at the normal boiling point. The average absolute deviation for the calculated densities of 11 refrigerants is 1.1%.

Maximum on the Electrical Conductivity Polytherm of Molten TeCl4

The electrical conductivity of molten TeCl4 was measured up to 761K, i.e. 106 degrees above the normal boiling point of the salt. For the first time it was found that TeCl4 electrical conductivity polytherm has a maximum. It was recorded at 705K (κmax=0.245 Sm/cm), whereupon the conductivity decreases as the temperature rises. The activation energy of electrical conductivity was calculated.