Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 66-70). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1975. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--University of New South Wales, 1995. / Completed at: University of New South Wales, School of Chemical Engineering and Industrial Chemistry. Title from electronic deposit form.

Thesis (MScEng)--University of Stellenbosch, 2008. / Bibliography. Also available via the Internet.

Thesis (M.S.)--University of Missouri-Columbia, 2004. / Typescript. Includes bibliographical references (leaves 66-70). Also available on the Internet.

Thesis (Ph. D.)--University of Wisconsin--Madison, 1970. / Typescript. Vita. eContent provider-neutral record in process. Description based on print version record. Includes bibliography.

Thesis (Ph. D.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2008. / Koros, William J., Committee Chair ; Breedveld, Victor, Committee Member ; Jones, Christopher W., Committee Member ; Kumar, Satish, Committee Member ; Nair, Sankar, Committee Member.

Thesis (M.S.)--Humboldt State University, 2007. / Includes bibliographical references (leaves 81-82). Also available via Humboldt Digital Scholar.

In this dissertation the power draw, the mass transfer and the liquid mixing behaviour of boiling and hot sparged stirred tank reactors (STRs) were investigated. The power draw characteristics of six different impellers were studied under varying operating conditions and expressed in terms of the relative power draw, RPD. Generally the impellers showed considerably higher power draw in hot gassed than in comparable cold conditions. The main phenomenon in hot systems, the evaporation of liquid into a gas bubble suddenly exposed to it, was investigated experimentally. The growth of nitrogen and air bubbles in hot water was found to be very fast and be completed typically within milliseconds after their exposure to the liquid. This was confirmed by studies applying acoustic bubble sizing techniques which were carried out together with Richard Manasseh from CSIRO, Melbourne, Australia. Experimental studies of the gas-liquid mass transfer in hot sparged STRs were carried out using a tank of 450 mm in diameter agitated by a 180 mm Rushton turbine. Experiments involving the temperature kinetics in an air-water system and absorption and desorption of ammonia were used to determine gas and also some liquid side mass transfer coefficients. The gas side coefficients kga were found to be typically in the order of 0.01 s-1. An enhancement of the liquid side mass transfer was also observed. Both Fick and Stefan-Maxwell models were employed to express gas side mass transfer coefficients. The models predict there will be a decrease of the coefficients at high concentrations. In the hot sparged tank the temperature is essentially uniform throughout the STR. Liquid mixing times have been measured for various boil-off and sparging rates. No significant deviations from the single phase or the cold gassed mixing times in this equipment were recorded.

The work presented in this thesis has focused on the development and implementation of two-dimensional (2D) nuclear magnetic resonance (NMR) correlation techniques to unambiguously discriminate and characterise competitive adsorption and mass transfer processes in porous materials. This has primarily involved investigations on porous oxides; in particular silicas and aluminas commonly used as catalyst supports. The techniques used are demonstrated to be capable of acquiring information relevant to the performance of heterogeneous catalysts and adsorbents across the hierarchy of length scales relevant to industrial processes. The methodologies associated with the acquisition and processing of 2D NMR correlation data were first established through the development of analytical models capable of simulating 2D signal attenuation data for T1-T2, D-T2 and T2-T2 experiments. Common artefacts were also discussed by means of experimental and simulated examples and, where appropriate, methods have been introduced for their prevention. The NMR relaxation behaviour of water saturating the pore space of silica was observed to correlate strongly with independent measurements of the activation energy of dehydroxylation, thus establishing NMR relaxometry as a tool for directly probing the surface energetics of silica surfaces. This interpretation of T1/T2 ratios differs from that in conventional applications of the technique which typically present the ratio as an indicator of surface-adsorbate interaction strength. Here, the T1/T2 ratios of three liquid probe molecules: ethanol, diethyl ether and cyclohexane, are used to investigate the influence of pore size and density of adsorption sites on relaxation behaviour. Competitive adsorption behaviour has been directly investigated through the acquisition of T1-T2 correlation data of binary liquid mixtures imbibed in various silica supports. These measurements, in combination with a newly developed model for the relaxation of multi-component mixtures, have provided a comprehensive assessment of the ability of this technique to quantify intra-pellet compositions and address competitive adsorption behaviour in porous media. With the aid of a random walk Monte-Carlo model to simulate transverse relaxation in packed bed reactors, T2-T2 relaxation exchange measurements have been used to investigate mass transfer across the fluid-solid boundary in a packed bed reactor filled with γ-alumina and liquid cyclohexane. These data were used to quantify the rate of exchange between intra- and inter-pellet environments at a number of flow rates. Exchange rates were then converted into the more convenient terms of mass transfer coefficients and compared against literature data using two separate dimensionless mass transfer analyses.