High pressure vapor-liquid equilibria involving mixtures of dimethyl ether, freon-22, alcohols, and water

Knowledge of the phase behavior of fluid mixtures is of a special interest to many chemical processes such as extraction, leaching, drying, simulation of petroleum reservoirs, and enhanced oil recovery. Therefore, it is of relevance to be able to produce accurate phase equilibrium data as well as reliable models for calculating phase equilibrium at elevated temperatures and pressures.; An apparatus has been built to accurately generate new high pressure vapor-liquid equilibrium data (VLE) for binary and aqueous ternary systems at temperatures and pressures up to 110°C and 12 MPa respectively. The experimental apparatus is a dynamic circulation continuous flow type where the vapor and the liquid are circulated inside an equilibrium cell thoroughly and continuously at a constant temperature until vapor-liquid equilibrium is achieved. The experimental system consists mainly of an equilibrium cell, two magnetic pumps, sampling valves, high pressure pumps, a constant air bath, and a gas chromatograph.; The reliability of a Thornton apparatus to reproduce and generate new vapor-liquid equilibrium data at atmospheric pressure is demonstrated. Most of the low pressure apparatus are capable of sampling the liquid phase only. The vapor phase is then calculated from equations of state. The uniqueness of our apparatus is its capability of circulating the liquid and vapor phases and sampling both phases simultaneously.; The experimental phase equilibrium data are correlated using the Elliott-Suresh-Donohue (ESD) and Peng-Robinson (PR) equations of state. The ESD is a semiempirical model for the representation of thermodynamic properties for non-spherical and associating mixtures. It accounts for selfassociation (hydrogen bonding interaction between similar molecules) and cross-association (hydrogen bonding interaction between different molecules) for systems with multiple associating species. The ESD shows that there is evidence of self-associations and cross-associations in the fluid mixtures studied. The ESD has been able to very accurately address the effect of association and hydrogen bonding.; The last section of the thesis is an expletory study to demonstrate the ability of constructing high pressure apparatus based on stoichiometric technique that does not require sampling to determine the contents of each phase. From the overall known composition, volumetric data, temperature, and pressure, the liquid and vapor phase compositions are determined.