No description available.

Thesis (M. Sc.)--University of Alberta, 2010. / Title from pdf file main screen (viewed on June 21, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Master of Science in Chemical Engineering, Department of Chemical & Materials Engineering, University of Alberta. Includes bibliographical references.

Not available / text

Not available / text

Not available / text

A thesis submitted for the degree of Doctor of Philosophy to The Department of Chemical and Metallurgical Engineering, Faculty of Engineering, University of the Witwatersrand, Johannesburg, 2016 / Separation of materials is crucial to the operation of the majority of chemical processes, not only for the purification of final products but also for the processing of feed-stocks prior to chemical reaction. The most commonplace method of materials separation is distillation which, unfortunately, is often an energy-intensive process and contributes significantly to mankind’s energy consumption and carbon dioxide emissions. Alternative approaches to separation are therefore a crucial element of the ongoing pursuit for sustainability in chemical industries. There are two principal ways of going about this. The first is to replace distillation units with alternative unit operations that can achieve the same separation with less energy expenditure. The second approach is overall flowsheet revision, fundamentally changing a separation cycle to minimize its energy requirements. The greatest improvements to energy efficiency will be achieved by applying both approaches in tandem. However, each must be developed separately to make that possible. This thesis lays the groundwork for radical revision of major separation operations by showcasing a new overall flowsheet for bioethanol separation that promises tremendous improvements in separation efficiency, reducing the energy usage involved in ethanol purification by as much as 40% in some scenarios. It also develops a novel method for the design of multi-membrane permeation units, showing how area ratio can be manipulated to fundamentally alter separation performance from such units, resulting in superior separation performance to conventional units, achieving higher recoveries than conventional setups. With membranes being an increasingly popular separation method, the potential for superior performance from multi-membrane units promises improvements in separation efficiency.

A gaseous diffusion column was designed, constructed, and its operation tested with a system of electrolytic hydrogen and carbon dioxide. The column contained one diffusion unit with two 6-inch diameter barrier areas. In the preliminary tests the flow rates of the hydrogen-carbon dioxide mixture were varied from 0 to 15 cubic feet per hour. Vacuum on the system was varied from 0 to 25 inches of mercury. Composition of the feed mixture was held constant at 50 mol per cent hydrogen and 50 mol per cent carbon dioxide. Temperature of the system varied with the surroundings from 75 to 85 °F. Barrier materials were of 0.008 inch thick fiber glass called Dexiglas mat obtained from Dexter and Sons, and 0.018-inch thick fiber glass Ultra Efficient Filter media mat obtained from Mine Safety Appliance Company. It was found that the hydrogen permeated at a rate greater than could be explained by diffusion alone, but which could be closely accounted for when adsorption and adsorbed flow were taken into account. The separation of a system of carbon dioxide and hydrogen by means of a fiber glass barrier could be adequately represented as a combination of gaseous diffusion and of adsorbed flow. Agreement of observed values was within five per cent with an estimate of gaseous diffusion using Weller and Steiner's equation plus a value for adsorbed flow from a modified version of Russell's equation. The separation of hydrogen from carbon dioxide in the equipment as constructed increased as the pressure increased from 10 to 20 inches of mercury for flow rates of one to ten cubic feet per hour for the gaseous mixture which is contrary to that predicted by pure gaseous diffusion. A permeability apparatus was constructed and operated with a system of .carbon dioxide and hydrogen. Composition of the feed mixture was either pure electrolytic hydrogen, pure carbon dioxide, or a mixture of 50 mol per cent hydrogen and 50 mol per cent carbon dioxide. Temperature of the system varied with the surroundings from 25 to 28 °C. Barrier materials of 0.008-inch thick fiber glass called Dexiglas obtained from Dexter and Sons, 0.001-inch thick polystyrene from Dow Chemical Company, 0.001-inch thick cellulose acetate supplied by Celanese Corporation, and silicone rubber obtained from General Electric Company, Silicone Division, were used in this investigation. The permeation of hydrogen and carbon dioxide checked previous work⁽⁶⁹⁾ which listed these barriers as having selective permeability to the gases used. The permeation of a mixture of carbon dioxide and hydrogen is in direct relationship with the adsorption of that mixture onto a powdered sample of the barrier material. / Ph. D.

A numerical analysis of laminar film condensation and the prediction of aerosol formation is presented for a gas-vapor mixture undergoing forced flow through a vertical tube. This analysis is useful for estimating the sizes and operating conditions of condensers used for removing vapors from gas-vapor mixtures. The ability to predict the possibility of aerosol formation without expensive experimental studies makes it practical to design condensers in which aerosol formation is impossible. Three different vapors (water, mercury, and benzene) mixed with air are considered in the analysis at three different inlet vapor mass fractions (50% of saturated, 75% of saturated, and saturated). The results indicate that condensers could effectively be used to remove vapors from gas/vapor mixtures and therefore, that design estimates could be determined from the model presented here. The results also show that inlet vapor mass fractions as low as 50% of saturation for water and benzene and 25% of saturation for mercury could cause aerosol formation in the bulk flow field. Aerosol formation degrades the performance of a condenser in removing vapor because the vapor condenses in the bulk flow where it is not easily removed without the use of a filtering medium. / Master of Science

Digitized by Kansas Correctional Industries

Abstract not available