Experimental Solid-liquid Equilibrium Data Research Articles

Measurement and Prediction of Ternary Solid−Liquid Equilibria

Solid−liquid equilibria (SLE) and liquidus lines for the ternary systems cyclohexane + benzene + 2-heptanone and acetonitrile + benzene + chloroform were determined by means of the synthetic visual method. The phase diagrams are represented in different graphical forms. The experimental SLE data were compared with results obtained by the modified UNIFAC (Dortmund) method. The prediction of ternary solid−liquid equilibria with the help of a reliable group contribution method is a suitable way for choosing selective solvents for extractive crystallization processes. A model comparison (original UNIFAC, modified UNIFAC (Dortmund), modified UNIFAC (Lyngby), and ASOG) for the prediction of about 325 ternary SLE systems taken from the Dortmund Data Bank shows superior results for mod. UNIFAC (Do) in comparison to the other methods.

Correlation of solid—liquid and vapor—liquid equilibrium data for polynuclear aromatic compounds

Solid—liquid equilibrium (SLE) data were measured for five solutes in cis-decalin from ambient temperature to the melting point of the solutes. These SLE data plus our previous data for the same solutes in tetralin were used to determine experimental activity coefficients and interaction parameters using the UNIQUAC model. This set of interaction parameters gave a good representation of the experimental SLE data but were not satisfactory generally for predicting vapor—liquid equilibria for these systems. However, in an alternative approach, the solid solubility data and one vapor—liquid equilibrium point for each isotherm from previous work were used to determine another set of binary interaction parameters in the UNIQUAC model using a gradient-based search technique. The calculated values of parameters were used then to predict the vapor—liquid equilibrium for that system. It was found that the solid solubility and one vapor—liquid equilibrium data point were sufficient to predict the vapor—liquid equilibrium curve for the binary systems studied. Finally, all the solid solubility and vapor—liquid equilibrium data were combined to determine global parameters for the ten binary systems using the UNIQUAC model.

Calculation of solid-liquid equilibria using the modified BWR equation of state of Lee and Kesler.

The solubility of solid hydrocarbons and inorganics (carbon dioxide and hydrogen sulfide) in liquid hydrocarbons was correlated using the modified BWR equation of state of Lee and Kesler and the pseudocritical method to compute the fugacity coefficient of the solute in subcooled liquid. This method requires two binary parameters, k12 and s12, for each binary pair to be computed from experimental solid-liquid equilibrium data. These parameters are tabulated for a large number of binary systems. The correlation resulting from this investigation will be valuable in the design of cryogenic processes.