Vapor−Liquid Equilibrium For The Mixture of m-Xylene, Ethylbenzene and 1, 2, 4-Trichlorobenzene at 101.3 kPa

The vapor-liquid phase equilibrium (VLE) data for binary systems of m-xylene + ethylbenzene, m-xylene + 1, 2, 4-trichlorobenzene, ethylbenzene + 1, 2, 4-trichlorobenzene and ternary system of m-xylene + ethylbenzene + 1, 2, 4-trichlorobenzene were determined with a modified Rose still at 101.3 kPa, and all the binary data passed the Wisniak’s test, which accorded with the thermodynamic consistency. Three activity coefficient models namely, Wilson, NRTL and UNIQUAC were used to correlate VLE data and get binary interaction parameters, then the ternary VLE data of m-xylene + ethylbenzene + 1, 2, 4-trichlorobenzene were estimated based on these model parameters using Aspen Plus software. The estimation values of the three models agree well with the experimental data. Moreover, the effect of 1, 2, 4-trichlorobenzene was analyzed, and it found to be an effective candidate extractant for the extractive distillation of ethylbenzene from mixed xylenes.

Asphaltene precipitation from heavy oil mixed with binary and ternary solvent blends

Models are required to predict the onset and precipitation of asphaltenes from mixtures of heavy oil and solvents for a variety of heavy oil applications. The regular solution approach is well suited for this objective but has not yet been tested on solvent mixtures. To do so, the onset and amount of asphaltene precipitation were measured and modeled for mixtures of heavy oil with solvent blends made up from n-alkanes, cyclohexane, and toluene at temperatures of 21 and 180 °C and pressures of 0.1 and 10 MPa. Temperature dependent binary interaction parameters (BIP) between the cyclohexane/asphaltene and toluene/asphaltene pseudo-component pairs were proposed to match the data. All other BIP were set to zero. The model with BIP determined from asphaltene precipitation in heavy oil and binary solvents predicted asphaltene precipitation from heavy oil and ternary solvent blends, generally to within the experimental error.

Correlation and prediction of solubility of hydrogen in alkenes and its dissolution properties

In this work, solubility of hydrogen in some alkenes was investigated at different temperatures and pressures. Solubility values were calculated using the Peng–Robinson equation of state. Binary interaction parameters were calculated using fitting the equation of state on experimental data, Group contribution method and Moysan correlations and total average absolute deviation for these methods was 3.90, 17.60 and 13.62, respectively. Because hydrogen solubility in Alkenes is low, Henry’s law for these solutions were investigated, too. Results of calculation showed with increasing temperature, Henry’s constant was decreased. The temperature dependency of Henry’s constants of hydrogen in ethylene and propylene was higher than to other alkenes. In addition, using Van’t Hoff equation, the thermodynamic parameters for dissolution of hydrogen in various alkenes were calculated. Results indicated that the dissolution of hydrogen was spontaneous and endothermic. The total average of dissolution enthalpy ($${\Delta H}^{^\circ }$$ Δ H ∘ ) and Gibbs free energy ($${\Delta G}^{^\circ }$$ Δ G ∘ ) for these systems was 3.867 kJ/mol and 6.361 kJ/mol, respectively. But dissolution of hydrogen in almost of alkenes was not an entropy-driven process.

Measurement and Correlation of Liquid-Liquid Equilibrium Data of Mesityl oxide-Diethoxymethane-Water System

To provide essential data for the separation of diethoxymethane and system water using mesityl oxide as the extractant, in this paper, the liquid-liquid equilibrium data of the ternary system of ‘mesityl oxide + diethoxymethane + water’ was measured at 303.2 K, 313.2 K and 323 K under normal pressure. The experimental results showed that partition coefficient and separation factor were both larger than 1, indicating that diethoxymethane and water could be well separated with mesityl oxide. The linear correlation coefficient of Bachman and Hand equation was larger than 0.99, indicating that our experimental data has good reliability. At the same time, the binary interaction parameters of the model were obtained by correlating the experimental data with the NRTL and UNIQUAC models. The relative root mean square error (RMSD) of the experimental value and the calculation formula was less than 0.79%, indicating that both the NRTL and UNIQUAC models can be well associated with experimental data.

An improved reduction method for phase stability testing in the single-phase region

A new reduction method for mixture phase stability testing is proposed, consisting in Newton iterations with a particular set of independent variables and residual functions. The dimension of the problem does not depend on the number of components but on the number of components with nonzero binary interaction parameters in the equation of state. Numerical experiments show an improved convergence behavior, mainly for the domain located outside the stability test limit locus in the pressure–temperature plane, recommending the proposed method for any applications in which the problematic domain is crossed a very large number of times during simulations.

Liquid-liquid Equilibrium Determination and Data Correlation for 2,2,4-trimethyl Pentane - tripropylene Glycol Binary System

Liquid-liquid equilibrium at temperatures between 293.16K and 353.1K for the mixture of 2,2,4-trimethylpentane + 2- [2- (2-Hydroxypropoxy) propoxy] -1-propanol was determined using the cloud point method. The measured data was used to estimate the binary interaction parameters of NRTL thermodynamic model, through non-linear regression using MATLAB� software. The binary interaction parameters resulting from regression were used further in a chemical simulation software (PRO/II 9.3) to determine the LLE for the studied mixture. The LLE calculation results obtained with the NRTL model were compared with the results of LLE calculations using the predictive thermodynamic model-UNIFAC. It was determined that the results of the calculation of the LLE using binary interaction parameters obtained through regression have a smaller deviation from the experimental data than the results of the calculation performed using the UNIFAC model. Moreover, the binary interaction parameters obtained from regression were utilized for the estimation of the solvency properties of tripropylene glycol considering the extraction of C8 aromatics from a mixture containing 2,2,4-trimethyl pentane, ethylbenzene and xylenes.