Thesis (Ph. D.)--University of New South Wales, 2005. / Also available online.

Thesis (Ph. D.)--University of Washington, 1994. / Vita. Includes bibliographical references (leaves [162]-170).

Thesis (Ph. D.)--University of Canterbury, 2010. / Typescript (photocopy). Includes bibliographical references. Also available via the World Wide Web.

Thesis (M. S.)--Chemical and Biomolecular Engineering, Georgia Institute of Technology, 2007. / Koros, William, Committee Member ; Hsieh, Jeffery, Committee Chair ; Deng, Yulin, Committee Member.

A novel approach to enhance the concentration of Carbon dioxide to economic scale using low efficient Inorganic Ceramic membranes has been proposed. This was achieved by the addition of second and third stage permeation trains to the existing low CO2 recovering Ceramic Inorganic membranes. The Inorganic Ceramic membrane development involved modification of Alpha Alumina support with Gamma Alumina for improved surface area. Further modifications with Magnesium Oxide and Silicon Elastomer showed increase in the selectivity of Carbon dioxide molecules over Nitrogen, Methane, Argon, and Helium molecules, both in pure and mixture forms. A simulated flue gas feed concentration of CO2-14% and N2-86% was found to be concentrated more than 90% of CO2. The Carbon dioxide permeability was found to decrease as the membrane thickness and number of dipping increased, whereas, the selectivity of the Carbon dioxide over Nitrogen, Argon, Helium and Methane molecules improved with the use of modified membranes compared to membrane support only. The testing of the fabricated membrane demonstrated that modified membrane at third stage permeation at a pressure drop of 9.00KPa and operating temperature of 296K was capable of recovering more than 90% of Carbon dioxide from a feed gas mixture of 14%-CO2 and N2-86%.The permeability of the Carbon dioxide gas molecules that was recovered at the above listed operating conditions was 4.26X10-12 (mol.m/m2.s.Pa). This was achieved by surface flow mechanism and membrane pore sizes estimated were found to be macroporoes and mesopores with their EDXA and SEM images. A numerical algorithm was used to estimate the errors. The error was found to decrease as the permeation value increases.

Atualmente, existe no mundo a necessidade de buscar alternativas aos combustíveis fósseis por fontes renováveis para a produção de energia. O gás natural possui vantagens significativas em relação a outros combustíveis fósseis, em especial pela redução nas emissões atmosféricas provenientes da sua combustão. O uso do metano presente no biogás é uma alternativa renovável ao uso do gás natural nas suas diversas aplicações, incluindo gás natural veicular. Para separação de metano, membranas têm recebido grande atenção devido às diversas vantagens, tais como eficiência energética na operação e baixo impacto ambiental com relação à outras tecnologias. Membranas poliméricas de poli (fluoreto de vinilideno) (PVDF) e polissulfona (PSf) foram sintetizadas através do método de inversão de fases. A realização de ensaios de permeação sob uma faixa de pressão de operação entre 2 e 5 bar, e sob uma faixa de temperatura de operação entre 20 e 45°C, e a análise da morfologia das membranas através de microscopia eletrônica de varredura em amostras das membranas, permitiram que fossem identificados os mecanismos de transporte atuantes nas membranas poliméricas. Os mecanismos de transporte contribuíram para a investigação e o entendimento da influência dos parâmetros de operação (temperatura e pressão) sobre a permeabilidade e a seletividade na separação de gases (CO2/CH4) nas membranas poliméricas. As membranas de poli (fluoreto de vinilideno) (PVDF) apresentaram elevada permeabilidade para ambos os gases em todas as pressões (2 a 5 bar) e temperaturas (20 a 45°C) estudadas, porém não se mostraram atraentes para esta aplicação devido à baixa seletividade na separação de gases, enquanto que as membranas de polissulfona (PSf) demonstraram boas perspectivas para esta aplicação, devido a uma melhor relação entre permeabilidade e seletividade. O incremento da pressão dentro da faixa estudada (2 a 5 bar) resultou em menores fluxos de permeado para o gás CO2, e fluxos de permeado constantes e por vezes maiores para o gás CH4. O incremento da temperatura aumentou o fluxo de permeado de ambos os gases. / Submitted by Ana Guimarães Pereira (agpereir@ucs.br) on 2015-02-23T17:07:47Z No. of bitstreams: 1 Dissertacao Lucas David Biondo.pdf: 222796 bytes, checksum: b99e9c379f231389dd82488dab084019 (MD5) / Made available in DSpace on 2015-02-23T17:07:47Z (GMT). No. of bitstreams: 1 Dissertacao Lucas David Biondo.pdf: 222796 bytes, checksum: b99e9c379f231389dd82488dab084019 (MD5) / Currently, there is a need in the world to substitute fossil fuels for renewable sources in the energy production. Natural gas has significant advantages over other fossil fuels, in particular the reduction in atmospheric emissions from their combustion. The use of methane, present in biogas, is a renewable alternative instead of using natural gas in its various applications, including as an alternative energy for vehicles. Within this context, polymeric membranes have received great attention due to several advantages, such as energy efficiency in operation and low environmental impact regarding to other technologies. Polymeric Membranes of poly (vinylidene fluoride) (PVDF) and polysulfone (PSf) were synthesized by the phase inversion method. Permeation testing under a range of operating pressure between 2 and 5 bar, and under a range of operating temperature between 20 and 45 °C, together with morphology analysis by scanning electron microscopy, allowed to identify the transport mechanism acting in the polymeric membranes. The transport mechanisms contributed to investigate and understand the influence of operating parameters (temperature and pressure) on permeability and selectivity in gas separation (CO2/CH4) in the polymeric membranes. The membranes of poly (vinylidene fluoride) (PVDF) showed high permeability to both gases at all pressures (2 to 5 bar) and temperatures (20 to 45 °C) studied,, however, not attractive for this application due to low selectivity in gas separation, while the membranes of polysulfone (PSf) showed good prospects for this application, due to a better relationship between permeability and selectivity. Increasing pressure within the studied range (2 to 5 bars) resulted in lower permeate fluxes for CO2 and permeate flows constant and occasionally higher for CH4. The increase in temperature increased the permeate flux of both gases.

Submitted in part fulfillment of the requirements for the Degree of Masters in Technology in Chemical Engineering, ML Sultan Technikon, 2003. / Whilst microfiltration (MF) has numerous uses and advantages over conventional separation processes it does have certain limitations. MF membrane process can effectively remove turbidity but cannot sufficiently remove low molecular organics. For a sufficient removal of such particles adaptations and modifications to the membrane has to be made or additional removal processes (e.g. nanofiltration or reverse osmosis) has to be added. This project makes an attempt at addressing the former issue. In MF, a membrane on a support performs the filtration. There are various types of materials used as supports e.g. ceramics, porous steel tubes, polymers etc. These materials are usually rigid or semi-rigid and thus offer the advantage of maintaining their shape thus enabling operation at high pressures. This project will concentrate exclusively on woven fibre microfiltration (WFMF). This is a tubular cloth-like filter, which becomes rigid when feed flows into it. / M

Atualmente, existe no mundo a necessidade de buscar alternativas aos combustíveis fósseis por fontes renováveis para a produção de energia. O gás natural possui vantagens significativas em relação a outros combustíveis fósseis, em especial pela redução nas emissões atmosféricas provenientes da sua combustão. O uso do metano presente no biogás é uma alternativa renovável ao uso do gás natural nas suas diversas aplicações, incluindo gás natural veicular. Para separação de metano, membranas têm recebido grande atenção devido às diversas vantagens, tais como eficiência energética na operação e baixo impacto ambiental com relação à outras tecnologias. Membranas poliméricas de poli (fluoreto de vinilideno) (PVDF) e polissulfona (PSf) foram sintetizadas através do método de inversão de fases. A realização de ensaios de permeação sob uma faixa de pressão de operação entre 2 e 5 bar, e sob uma faixa de temperatura de operação entre 20 e 45°C, e a análise da morfologia das membranas através de microscopia eletrônica de varredura em amostras das membranas, permitiram que fossem identificados os mecanismos de transporte atuantes nas membranas poliméricas. Os mecanismos de transporte contribuíram para a investigação e o entendimento da influência dos parâmetros de operação (temperatura e pressão) sobre a permeabilidade e a seletividade na separação de gases (CO2/CH4) nas membranas poliméricas. As membranas de poli (fluoreto de vinilideno) (PVDF) apresentaram elevada permeabilidade para ambos os gases em todas as pressões (2 a 5 bar) e temperaturas (20 a 45°C) estudadas, porém não se mostraram atraentes para esta aplicação devido à baixa seletividade na separação de gases, enquanto que as membranas de polissulfona (PSf) demonstraram boas perspectivas para esta aplicação, devido a uma melhor relação entre permeabilidade e seletividade. O incremento da pressão dentro da faixa estudada (2 a 5 bar) resultou em menores fluxos de permeado para o gás CO2, e fluxos de permeado constantes e por vezes maiores para o gás CH4. O incremento da temperatura aumentou o fluxo de permeado de ambos os gases. / Currently, there is a need in the world to substitute fossil fuels for renewable sources in the energy production. Natural gas has significant advantages over other fossil fuels, in particular the reduction in atmospheric emissions from their combustion. The use of methane, present in biogas, is a renewable alternative instead of using natural gas in its various applications, including as an alternative energy for vehicles. Within this context, polymeric membranes have received great attention due to several advantages, such as energy efficiency in operation and low environmental impact regarding to other technologies. Polymeric Membranes of poly (vinylidene fluoride) (PVDF) and polysulfone (PSf) were synthesized by the phase inversion method. Permeation testing under a range of operating pressure between 2 and 5 bar, and under a range of operating temperature between 20 and 45 °C, together with morphology analysis by scanning electron microscopy, allowed to identify the transport mechanism acting in the polymeric membranes. The transport mechanisms contributed to investigate and understand the influence of operating parameters (temperature and pressure) on permeability and selectivity in gas separation (CO2/CH4) in the polymeric membranes. The membranes of poly (vinylidene fluoride) (PVDF) showed high permeability to both gases at all pressures (2 to 5 bar) and temperatures (20 to 45 °C) studied,, however, not attractive for this application due to low selectivity in gas separation, while the membranes of polysulfone (PSf) showed good prospects for this application, due to a better relationship between permeability and selectivity. Increasing pressure within the studied range (2 to 5 bars) resulted in lower permeate fluxes for CO2 and permeate flows constant and occasionally higher for CH4. The increase in temperature increased the permeate flux of both gases.

Submitted in fulfilment of the academic requirements for the Degree of Masters in Technology: Chemical Engineering, M.L. Sultan Technikon, 2002. / Crossflow microfiltration (CFMF) using a fabric support has been successfully used to treat a range of problematic waters. Experimental evidence indicates that the formation of a dynamic membrane or precoat on a woven-fibre microfilter can significantly increase the performance of the filter, that is, the production rate and rejection. The use of precoats in filtration applications is based on the precoat's unique microstructure that is able to trap sub-micron particles while maintaining a permeable filter cake. However, to date the precoating step has been more of an art than a science. Very little knowledge exists on the best type of precoat to use, or the the optimal velocity, pressure and concentration to form a stable precoat. Further, although various models have been proposed for CFMF, their still exists a lack of knowledge of the mechanisms by which precoats improve performance. / M

Magister Scientiae - MSc / Over the past 40 years, research pertaining to membrane technology has lead to the development of a wide range of applications including beverage production, water purification and the separation of dairy products. For the separation of gases, membrane technology is not as widely applied since the production of suitable gas separation membranes is far more challenging than the production of membranes for eg. water purification. Hydrogen is currently produced by recovery technologies incorporated in various chemical processes. Hydrogen is mainly sourced from fossil fuels via steam reformation and coal gasification. Special attention will be given to Underground Coal Gasification since it may be of great importance for the future of South Africa. The main aim of this study was to develop low temperature CsHSO4/SiO2 composite membranes that show significant Idea selectivity towards H2:CO2 and H2:CH4. / South Africa