Date of Award
Doctor of Philosophy (PhD)
Phase equilibrium diagrams for systems containing compounds found in coal liquids and heavy crude oil are useful in designing separation processes and also in testing and developing of thermodynamic models. Solid-liquid equilibrium (SLE) data are easy to obtain compared with vapor-liquid equilibrium (VLE) data for systems that are solid near room temperature, because the solids melt to liquids and have relatively high boiling points. It may be possible to extrapolate activity coefficients derived from SLE data to higher temperatures and thus predict vapor-liquid equilibrium. This dissertation presents new SLE and VLE data for compounds related to coal liquids. The problem of obtaining VLE data from SLE data is investigated. Vapor-liquid equilibrium data were measured at 170 and 190$\sp\circ$C for 15 binary and 8 ternary systems containing polynuclear aromatic compounds. Binary VLE data were correlated using five different activity coefficient models and regular solution theory to determine the non-ideality of the liquid mixtures. Ternary vapor-liquid equilibrium data were predicted using the interaction parameters obtained from regression of binary data for the UNIQUAC, Wilson, and regular solution theory models. Solid-liquid equilibrium data were also measured for five systems containing the same compounds. These solid solubility data along with one vapor-liquid point were used to predict the vapor-liquid equilibrium curve for each binary system. SLE and VLE data were also combined to determine global parameters valid from 298 to 463 K. Finally, experimental studies and predictions of the solid-liquid phase diagram of ternary systems containing two solutes were also carried out. The study of such phase diagrams is an important tool in analyzing various chemical engineering processes such as crystallization and extraction.
Gupta, Ajay, "Low-Pressure Phase Equilibria of Heavy Aromatic Compounds." (1991). LSU Historical Dissertations and Theses. 5238.