Call number: LD2668 .T4 1963 C59 / Master of Science

Interfacially active reagents are utilized in metal solvent extraction processes and it is therefore important to understand the role of the liquid-liquid interface in the study of the kinetics and equilibria of extraction. The diffusion problems encountered in the traditional apparatus were overcome by using a high speed stirring apparatus. The microporous teflon membrane phase separator permitted more accurate measurements of interfacial areas, characterization of extraction kinetics of metal chelates, and a greater understanding of the phase separation mechanism. In contrast to the neutral ligands, the anionic ligand of dithizones and substituted dithizones showed significant interfacial adsorption at the chloroform/water interface as monitored spectro-photometrically. Equilibrium studies on p-halodithizones indicated that the adsorption constant increased as the substituent was altered from chloro to bromo to iodo, and with the distribution ratio of the ligand. Kinetic studies on dithizone and p-iododithizone with Ni(II) and Zn(II) indicated that the extent of participation of the interface in solvent extraction kinetics of these metal ions is dictated by the interfacial activity of the extractant and the mechanisms of the rate limiting step in the bulk aqueous and interfacial regions.

The vapour recirculation apparatus of Moodley [2002] was modified, reconstructed, and commissioned in order to be used in the acquisition of high-pressure vapour-liquid equilibrium (HPVLE) data at low temperatures. The original equipment of Moodley [2002] was modified with the aim of achieving the desired operating temperature range which the original equipment was unable to achieve. Major modifications were carried out on the cooling circuit allowing the equipment to reach temperatures as low as -30°C, a significant improvement to the original equipments minimum attainable temperature of -5°C. Modifications were also successfully carried out on the vapour recirculation pump of Moodley [2002], which failed when operated over extended periods at high pressures thus enabling the equipment to operate at pressures up to 10.0 bar, an improvement on the previous pressure operating limit of 6.9 bar. The operating limits of the equipment were tested through measurement of pure-component vapour-pressures of isopentane at temperatures between -14 and +27.9°C and pressures up to 10.1 bar and on propane at temperatures between -30.1 and +26.0°C and pressures up to 9.7 bar. The isopentane vapour-pressure measurements had an average deviation of ±0.49% when compared to literature data while the propane vapour-measurements had a maximum average deviation of ±0.35% when compared to literature data indicating that the equipment was capable of measuring accurate vapour-pressure data at temperatures down to -30°C and pressures up to 10.0 bar. The equipment was thereafter used in the acquisition of binary HPVLE data. Considerable time was spent developing and practicing the techniques used in the binary HPVLE measurements. Binary measurements were performed on the test system propane + 1- propanol at 19.9°C. To gain more confidence in the binary HPVLE measurements another test system, propane + isopentane was selected and binary HPVLE measurements were performed at 25°C and 0°C. The equipment was able to reproduce relatively accurate binary HPVLE results for the test systems at the selected isotherms. The equipment was thereafter used in the acquisition of a new set of binary HPVLE data for the propane + isopentane system at -10°C however owing to time constraints and chemical availability the acquisition of a complete set of data was not possible. The binary HPVLE data was thereafter regressed via the direct method. The Peng-Robinson (PR) equation of state (EOS) and the Soave-Redlich-Kwong (SRK) EOS were each coupled with the Mathias Copeman alpha function together with the Wong-Sandler mixing rule and the NRTL local composition model and applied to the binary systems at each of the isotherms investigated. Regressed data showed a relatively good agreement with measured experimental data for both binary systems investigated at all of the isotherms except the new -10°C isotherm of the propane + isopentane system. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2010.

Call number: LD2668 .T4 1959 T34

A thesis submitted to the Faculty of Engineering, University of the Witwatersrand, Johannesburg, South Africa in fulfilment of the requirements for the degree of Doctor of Philosophy. / The aim of process synthesis is to select process equipment and interconnections in order to achieve some performance goal, such as the composition of one or more products, in an optimal manner. This work focuses on the synthesis and optimization of vapour-liquid equilibrium (VLE) separation processes. The regions of feasible products for a range of VLE separation processes (including simple distillation, simple condensation and processes comprised of one or two flash stages and mixing) are determined and analyzed. Binary and ternary systems, both ideal and non-ideal, are considered. It is shows .at the products of VLE separation processes are not inherently restricted; limitations in product composition are therefore introduced by the choice of separation equipment. The products on the boundary of the region of feasible products are often found to be associated with infinite costs. Therefore costs and, product composition should he considered simultaneously in process synthesis. This work introduces a pair of variables which are proposed as cost indicators for VLE separation processes. These variables, which are called "capacity variables", pertain to distillation columns and a wide range of other VLE separation processes, allowing their comparison. The variables incorporate both capital and energy costs of a process and are thus related to total annual costs. They accommodate costs of both boiling and condensing. They ate simple to calculate from the mass balance equations. The capacity variables are analogous to mean residence time, which serves as a cost indicator for processes invoi ving reaction. The capacity variables are evaluated for a range of processes separatins binary and ternary mixtures and a range of thermodynamic systems. The capacity variables reflect the impact of the operating parameters, such as product specifications and reflux ratio, on process costs. In distillation processes, the optimum reflux ratio is found to be close to the beuristic value of 1.2 times the minimum reflux ratio. The capacity variables are proposed as useful tools for the initial stages of process synthesis. / Andrew Chakane 2018

Thesis (Ph. D.)--University of Washington, 1991. / Vita. Includes bibliographical references (leaves [117]-123).

No description available.

No description available.

No description available.

High pressure vapour-liquid equilibrium experiments were undertaken with a static high-pressure apparatus designed by Prof. J. D. Raal and commissioned by Prof. D. Ramjugernath. Isothermal VLE binary data data was measured at moderate temperatures and pressures ranging from atmospheric to 7.2 bar. The equipment had a combined operating pressure and temperature limit of approximately 150 bar and 215° C respectively. The apparatus was initially designed for the measurement of gas-liquid binary systems- where one of the components was supercritical at the operating conditions. Test data were measured for the pentane + ethanol system at 100.41°C. The 2-methyl-2-butene + TAME, hydrocarbon + olefin system, was observed at 70°C, 94.6°C and 104.5°C. The apparatus was modified for the measurement of binary systems containing sub-critical components at the operating conditions specified. An injection port was installed on the apparatus assembly such that the second component of the binary system could be introduced into the equilibrium cell. The binary VLE data was regressed using various thermodynamic models. The direct method or phi-phi approach was considered. The equations of state models used in the regression were the Peng-Robinson-Stryjek-Vera (PRSV) and Soave-Redlich-Kwong (SRK). The 1-fluid van der Waals, Wong and Sandler mixing rules were selected to estimate binary interactions. The excess Gibbs energy equations coupled with the Wong and Sandler mixing rules were the NRTL and WILSON equations. / Thesis (M.Sc.Eng.)-University of KwaZulu-Natal, Durban, 2009.