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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

The Design of Continuous Chromatography for Separation and Purification

David M Harvey (8782685) 30 April 2020 (has links)
Continuous chromatography is an attractive alternative to traditional batch chromatography because it can have higher productivity, solvent efficiency, and product concentrations. However, several barriers prevent further use of continuous chromatography. There are many operating parameters that must be determined when designing continuous systems making it difficult to achieve high purity, yield, and productivity. Through the identification and strategic combination of the key dimensionless groups that control a continuous separation, it is possible to design highly productive systems that produce products with high yield and high purity. In this dissertation, three examples were selected to demonstrate the significance of a model-based method when designing continuous chromatography systems. (1) The Speedy Standing Wave Design and simulated moving bed splitting strategies for the separation of ternary mixtures with linear isotherms. (2) The Standing-wave Design of Three-Zone open-loop non-isocratic SMB for purification. (3) The Continuous Ligand-Assisted Displacement for the separation of Rare Earth Elements.<div>In the first example, the Speedy Standing Wave Design equations were developed for multicomponent separations with linear isotherms and a systematic splitting strategy was developed for the design of multiple sequential Simulated Moving Beds (SMBs). By performing the easiest split first, the overall productivity and solvent efficiency can be significantly improved. Rate model simulations were used to verify that the SSWD equations achieved target yields and purities. In systems where only one component is desired, the sorbent should be selected such that this component is the most or least retained so that it can be separated in a single SMB.</div><div>In the second example, the Standing Wave Design method was extended to non-isocratic three zone open loop SMBs. The standing wave design equations were derived and then verified using rate model simulations. In two case studies it was shown that non-isocratic SMBs designed using the standing wave design method show an order of magnitude higher productivity than a comparable batch system when the impurities are weakly adsorbing. When the impurities are competitive, the SWD method produces SMB systems with 2 orders of magnitude higher productivity than comparable batch systems. Because the design is based on dimensionless groups, the resulting designs are easily scalable and no rate model simulations are required to design high yield, high purity, and high productivity SMBs.</div><div>In the third example, the constant pattern design method was extended to continuous LAD systems. A continuous operation mode was developed that reduced the cycle time of LAD systems to further increase the productivity. In cases where the feed was equimolar, the continuous configuration increased the productivity between 20-50%. A multizone continuous LAD configuration was developed for the separation of a complex mixture of Dy, ND, and Pr that simulated a crude magnet feed. The resulting overall productivity for this system was 190 kg/m<sup>3</sup>day which was two orders of magnitude higher than a single column batch system and 70% higher than a multizone batch system. The robustness of the constant pattern design method was demonstrated through a simulated case study and it was determined that adding a safety factor through the reduction of the flowrate was more effective than reducing the design length.</div><div>Using a model-based design allows for the consistent design of continuous chromatography systems. The effects of a change in a feed or operating condition can be more easily understood through the lens of the model. This means that adjustments can be made pre-emptively when necessary and the new designs can be tested with virtual experiments before being implemented. The understanding of key dimensionless groups allows for designs that meet key design criteria at all scales of operation and thus allows for the easy transition from one scale to another.</div>
2

Problemas direto e inverso de processos de separação em leito móvel simulado mediante mecanismos cinéticos de adsorção / Direct and inverse problems of separation processes moving bed simulated by kinetic mechanisms of adsorption

Kamilla Vogas Romualdo 21 December 2012 (has links)
Diversas aplicações industriais relevantes envolvem os processos de adsorção, citando como exemplos a purificação de produtos, separação de substâncias, controle de poluição e umidade entre outros. O interesse crescente pelos processos de purificação de biomoléculas deve-se principalmente ao desenvolvimento da biotecnologia e à demanda das indústrias farmacêutica e química por produtos com alto grau de pureza. O leito móvel simulado (LMS) é um processo cromatográfico contínuo que tem sido aplicado para simular o movimento do leito de adsorvente, de forma contracorrente ao movimento do líquido, através da troca periódica das posições das correntes de entrada e saída, sendo operado de forma contínua, sem prejuízo da pureza das correntes de saída. Esta consiste no extrato, rico no componente mais fortemente adsorvido, e no rafinado, rico no componente mais fracamente adsorvido, sendo o processo particularmente adequado a separações binárias. O objetivo desta tese é estudar e avaliar diferentes abordagens utilizando métodos estocásticos de otimização para o problema inverso dos fenômenos envolvidos no processo de separação em LMS. Foram utilizados modelos discretos com diferentes abordagens de transferência de massa, com a vantagem da utilização de um grande número de pratos teóricos em uma coluna de comprimento moderado, neste processo a separação cresce à medida que os solutos fluem através do leito, isto é, ao maior número de vezes que as moléculas interagem entre a fase móvel e a fase estacionária alcançando assim o equilíbrio. A modelagem e a simulação verificadas nestas abordagens permitiram a avaliação e a identificação das principais características de uma unidade de separação do LMS. A aplicação em estudo refere-se à simulação de processos de separação do Baclofen e da Cetamina. Estes compostos foram escolhidos por estarem bem caracterizados na literatura, estando disponíveis em estudos de cinética e de equilíbrio de adsorção nos resultados experimentais. De posse de resultados experimentais avaliou-se o comportamento do problema direto e inverso de uma unidade de separação LMS visando comparar os resultados obtidos com os experimentais, sempre se baseando em critérios de eficiência de separação entre as fases móvel e estacionária. Os métodos estudados foram o GA (Genetic Algorithm) e o PCA (Particle Collision Algorithm) e também foi feita uma hibridização entre o GA e o PCA. Como resultado desta tese analisouse e comparou-se os métodos de otimização em diferentes aspectos relacionados com o mecanismo cinético de transferência de massa por adsorção e dessorção entre as fases sólidas do adsorvente. / Several important industrial applications involving adsorption processes, citing as an example the product purification, separation of substances, pollution control and moisture among others. The growing interest in processes of purification of biomolecules is mainly due to the development of biotechnology and the demand of pharmaceutical and chemical products with high purity. The simulated moving bed (SMB) chromatography is a continuous process that has been applied to simulate the movement of the adsorbent bed, in a countercurrent to the movement of liquid through the periodic exchange of the positions of input and output currents, being operated so continuous, notwithstanding the purity of the outlet streams. This is the extract, rich in the more strongly adsorbed component, and the raffinate, rich in the more weakly adsorbed component, the method being particularly suited to binary separations. The aim of this thesis is to study and evaluate different approaches using stochastic optimization methods for the inverse problem of the phenomena involved in the separation process in LMS. We used discrete models with different approaches to mass transfer. With the benefit of using a large number of theoretical plates in a column of moderate length, in this process the separation increases as the solute flowing through the bed, i.e. as many times as molecules interact between the mobile phase and stationary phase thus achieving the equilibrium. The modeling and simulation verified in these approaches allowed the assessment and identification of the main characteristics of a separation unit LMS. The application under consideration refers to the simulation of the separation of Ketamine and Baclofen. These compounds were chosen because they are well characterized in the literature and are available in kinetic studies and equilibrium adsorption on experimental results. With the results of experiments evaluated the behavior of the direct and inverse problem of a separation unit LMS in order to compare these results, always based on the criteria of separation efficiency between the mobile and stationary phases. The methods studied were the GA (Genetic Algorithm) and PCA (Particle Collision Algorithm) and we also made a hybridization between the GA and PCA. This thesis, we analyzed and compared the optimization methods in different aspects of the kinetic mechanism for mass transfer between the adsorption and desorption of the adsorbent solid phases.
3

Problemas direto e inverso de processos de separação em leito móvel simulado mediante mecanismos cinéticos de adsorção / Direct and inverse problems of separation processes moving bed simulated by kinetic mechanisms of adsorption

Kamilla Vogas Romualdo 21 December 2012 (has links)
Diversas aplicações industriais relevantes envolvem os processos de adsorção, citando como exemplos a purificação de produtos, separação de substâncias, controle de poluição e umidade entre outros. O interesse crescente pelos processos de purificação de biomoléculas deve-se principalmente ao desenvolvimento da biotecnologia e à demanda das indústrias farmacêutica e química por produtos com alto grau de pureza. O leito móvel simulado (LMS) é um processo cromatográfico contínuo que tem sido aplicado para simular o movimento do leito de adsorvente, de forma contracorrente ao movimento do líquido, através da troca periódica das posições das correntes de entrada e saída, sendo operado de forma contínua, sem prejuízo da pureza das correntes de saída. Esta consiste no extrato, rico no componente mais fortemente adsorvido, e no rafinado, rico no componente mais fracamente adsorvido, sendo o processo particularmente adequado a separações binárias. O objetivo desta tese é estudar e avaliar diferentes abordagens utilizando métodos estocásticos de otimização para o problema inverso dos fenômenos envolvidos no processo de separação em LMS. Foram utilizados modelos discretos com diferentes abordagens de transferência de massa, com a vantagem da utilização de um grande número de pratos teóricos em uma coluna de comprimento moderado, neste processo a separação cresce à medida que os solutos fluem através do leito, isto é, ao maior número de vezes que as moléculas interagem entre a fase móvel e a fase estacionária alcançando assim o equilíbrio. A modelagem e a simulação verificadas nestas abordagens permitiram a avaliação e a identificação das principais características de uma unidade de separação do LMS. A aplicação em estudo refere-se à simulação de processos de separação do Baclofen e da Cetamina. Estes compostos foram escolhidos por estarem bem caracterizados na literatura, estando disponíveis em estudos de cinética e de equilíbrio de adsorção nos resultados experimentais. De posse de resultados experimentais avaliou-se o comportamento do problema direto e inverso de uma unidade de separação LMS visando comparar os resultados obtidos com os experimentais, sempre se baseando em critérios de eficiência de separação entre as fases móvel e estacionária. Os métodos estudados foram o GA (Genetic Algorithm) e o PCA (Particle Collision Algorithm) e também foi feita uma hibridização entre o GA e o PCA. Como resultado desta tese analisouse e comparou-se os métodos de otimização em diferentes aspectos relacionados com o mecanismo cinético de transferência de massa por adsorção e dessorção entre as fases sólidas do adsorvente. / Several important industrial applications involving adsorption processes, citing as an example the product purification, separation of substances, pollution control and moisture among others. The growing interest in processes of purification of biomolecules is mainly due to the development of biotechnology and the demand of pharmaceutical and chemical products with high purity. The simulated moving bed (SMB) chromatography is a continuous process that has been applied to simulate the movement of the adsorbent bed, in a countercurrent to the movement of liquid through the periodic exchange of the positions of input and output currents, being operated so continuous, notwithstanding the purity of the outlet streams. This is the extract, rich in the more strongly adsorbed component, and the raffinate, rich in the more weakly adsorbed component, the method being particularly suited to binary separations. The aim of this thesis is to study and evaluate different approaches using stochastic optimization methods for the inverse problem of the phenomena involved in the separation process in LMS. We used discrete models with different approaches to mass transfer. With the benefit of using a large number of theoretical plates in a column of moderate length, in this process the separation increases as the solute flowing through the bed, i.e. as many times as molecules interact between the mobile phase and stationary phase thus achieving the equilibrium. The modeling and simulation verified in these approaches allowed the assessment and identification of the main characteristics of a separation unit LMS. The application under consideration refers to the simulation of the separation of Ketamine and Baclofen. These compounds were chosen because they are well characterized in the literature and are available in kinetic studies and equilibrium adsorption on experimental results. With the results of experiments evaluated the behavior of the direct and inverse problem of a separation unit LMS in order to compare these results, always based on the criteria of separation efficiency between the mobile and stationary phases. The methods studied were the GA (Genetic Algorithm) and PCA (Particle Collision Algorithm) and we also made a hybridization between the GA and PCA. This thesis, we analyzed and compared the optimization methods in different aspects of the kinetic mechanism for mass transfer between the adsorption and desorption of the adsorbent solid phases.

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