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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

Numerical solution of optimal control problems with implicitly defined discontinuities with applications in engineering

Brandt-Pollmann, Ulrich. January 2004 (has links) (PDF)
Heidelberg, University, Diss., 2004.
2

Enzymatic production of sugar fatty acid esters

Yan, Youchun. January 2001 (has links)
Stuttgart, Univ., Diss., 2001.
3

Heteroazeotropdestillation als Verfahren zur Trennung thermisch empfindlicher Substanzen

Ottenbacher, Markus. January 2007 (has links)
Zugl.: Stuttgart, Univ., Diss., 2007. / Druckausg. im Logos-Verlag, Berlin erschienen.
4

Numerically Optimized Diabatic Distillation Columns

Schaller, Markus 10 July 2007 (has links) (PDF)
Im Gegensatz zur konventionellen adiabatischen Destillation erfolgt bei der diabatischen Destillation Wärmeaustausch nicht nur am Kondensator und Verdampfer, sondern auch innerhalb der Kolonne an den einzelnen Siebböden, was die Entropieproduktion (=Exergieverlust) des Destillationsprozesses stark reduziert. In dieser Arbeit werden Modellsysteme zur diabatischen Destillation von idealen binären Gemischen mittels numerischer Optimierung untersucht. Das Ausgangsmodell beschränkt sich auf die Minimierung der Entropieproduktion verursacht durch Wärme- und Massentransport im Inneren der diabatischen Destillationskolonne. Im zweiten Modell wird das diabatische Modell um die Irreversibilität bedingt durch den Wärmeaustausch mit der Umgebung erweitert. Im dritten Modellsystem wird anstelle der bis dahin voneinander unabhängig geregelten Bodentemperaturen eine diabatische Implementierung mit seriellen Wärmetauschern untersucht, die nur mehr vier Kontrollvariablen besitzt und besonders zur praktischen Anwendung geeignet ist. Für alle diabatischen Modelle werden die minimale Entropieproduktion und optimalen Betriebsprofile numerisch ermittelt, und mit konventionellen Destillationskolonnen verglichen. Alle Ergebnisse zeigen eine deutlich Reduktion der Entropieproduktion für den diabatische Fall, besonders bei Kolonnen mit vielen Böden. / Contrary to conventional adiabatic distillation, in diabatic distillation columns heat transfer not only happens at the condenser and reboiler but also at the intermediate trays which strongly reduces the entropy production (= exergy losses). In this work, model systems for the diabatic distillation of ideal binary mixtures are investigated numerically.The first model is restricted to the minimization of the entropy production due to heat and mass transfer inside the diabatic column. In the second approach the model is extended with the irreversibility due to heat transfer with the column's surroundings. Instead of independently controlled tray temperatures as in the latter models, we focus on a specific diabatic implementation with sequential heat exchangers, which has merely four controls and which is particularly suitable for practical application. For all diabatic models the minimum entropy production and resulting optimal operating profiles are determined numerically, and compared to the ones obtained for a conventional column. All results show an enormous reduction of the entropy production for the diabatic case, especially for columns with many trays.
5

Simulação de destilador molecular de filme descendente para destilar frações pesadas de petroleo / Simulation of falling film molecular distillator for istillations of petroleum heavy fraction

Mallmann, Evandro Stoffels, 1983- 15 August 2018 (has links)
Orientador: Rubens Maciel Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-15T12:56:55Z (GMT). No. of bitstreams: 1 Mallmann_EvandroStoffels_M.pdf: 5927500 bytes, checksum: 1142d105683d77d9dfbe069513e8abce (MD5) Previous issue date: 2010 / Resumo: O Petróleo obtido nas bacias brasileiras é do tipo pesado e ultra pesado, apresentando alta viscosidade, que dificulta sua exploração (retirada do petróleo dos campos submarinos) e também as operações de refino para obtenção de combustíveis outros derivados. Os processos de refino atualmente em atividade nas refinarias não permitem a operação de óleos pesados e ultra pesados, de forma que estes são misturados a óleos leves para seu processamento. Este procedimento leva à dependência do Brasil em importação de petróleo, assim como a não completa valoração do óleo encontrado no país. Dentro deste contexto, a utilização da Destilação Molecular se apresenta como alternativa à operação inicial de óleos pesados e ultra pesados. Experimentos realizados nos Laboratórios de Desenvolvimento de Processos Separação (LDPS) e de Otimização, Projeto e Controle Avançado (LOPCA) mostraram a viabilidade de seu emprego. Porém, é necessária uma ampla investigação para desenvolvimento de políticas operacionais que levem a operação de destiladores moleculares com alto desempenho para refino de petróleo. Para tanto, é necessário o desenvolvimento de simulações que permitam um extensivo estudo cobrindo as possíveis faixas operacionais, que são funções das características do petróleo. Propõe-se assim, neste trabalho, o desenvolvimento de simulações para a destilação molecular tipo filme descendente fazendo-se uso do simulador comercial Aspen Plus®, que possui facilidades de pacotes termodinâmicos para a realização da tarefa. Dados experimentais já disponíveis foram usados para a análise e avaliação das simulações. / Abstract: The petroleum gotten in the Brazilian basins is of the types heavy and ultra-heavy, presenting high viscosities that make difficult its exploration (remove of the oil from submarine fields) and also the operations of refining for fuel attainment and other derivatives. The processes of refining, currently in activity, in the refineries, do not allow the heavy and ultra-heavy oil operation, so that these are mixed with light oils for its processing. This procedure leads to the dependence of Brazil in importation of oil, as well as not complete valuation of the oil found in the country. Inside this context, the use of molecular distillation is presented as an alternative to initial operation of heavy and ultra-heavy oil. Experiments carried through in the Laboratories of Development of Processes of Separation (LDPS) and Optimization, Project and Advanced Control (LOPCA) had shown the viability of this operation. However, is necessary an ample inquiry for development of operational politics that take the operation of molecular distillers with high performance for oil refining. For this purpose, the development of simulations that allow an extensive study covering the possible operational bands, that are functions of the characteristics of the oil, is necessary. It is considered thus, in this work, the development of a descendant filmed distiller simulations using the commercial simulator Aspen Plus®, that possess easiness of thermodynamic packages for the accomplishment of the task. Available experimental data were used for the analysis and evaluation of the simulations. / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
6

Simulação e analise da coluna de destilação a vacuo da unidade de destilação de processos de refino de petroleo / Simulation and analysis of vacuum distillation column from distillation unit of petroleum refinery processes

Maia, Júlio Pereira, 1978- 12 August 2018 (has links)
Orientador: Maria Regina Wolf Maciel / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-12T12:30:40Z (GMT). No. of bitstreams: 1 Maia_JulioPereira_M.pdf: 1976654 bytes, checksum: 7db1c6ceb65b53e42be6af7e578eb0f0 (MD5) Previous issue date: 2007 / Resumo: Unidades de vácuo para destilação de petróleo são estudadas neste trabalho. A destilação a vácuo é empregada para frações pesadas do petróleo, com vastas aplicações em processamento de crus pesados e ultra-pesados, motivado pelas dificuldades em se processar estes crus a pressão atmosférica devido ao alto ponto de ebulição dos componentes em suas composições. Estes compostos podem ser facilmente decompostos se não forem destilados abaixo da pressão atmosférica. Os produtos obtidos desta unidade são usados como insumos para a Unidade de Craqueamento Catalítico (UCC). Adotaram-se dois tipos de crus neste trabalho. Estes crus foram estabelecidos e caracterizados em um ambiente de simulação. Diferentes blends dos óleos foram considerados. Como unidades de vácuo estão conectadas com unidades atmosféricas, ambas as unidades foram simuladas no estado estacionário. A unidade atmosférica foi simulada com os equipamentos auxiliares principais. Produtos da unidade atmosférica foram determinados, e procedimentos para ajustar as variáveis de sistema de forma a fazer com que os produtos estivessem especificados foram apresentados. O projeto convencional de unidade de vácuo para produção de combustíveis foi o adotado para a simulação. Procedimentos para auxiliar a convergência da simulação desta unidade foram desenvolvidos. Uma análise de sensitividade foi conduzida, analisando as principais variáveis do sistema. Baseado nisso, um procedimento de otimização no estado estacionário foi adotado, levando em consideração os limites de convergência determinados para a análise de sensitividade. O sistema foi convertido do estado estacionário para se realizar uma simulação dinâmica. A simulação dinâmica foi conduzida com mudanças no fluxo de alimentação da torre atmosférica. O estabelecimento desta plataforma de simulação e sua disponibilidade foram muito importantes, bem como os resultados da simulação, por não ser facilmente encontrado na literatura aberta. Mais ainda, a grande complexidade deste processo de separação faz com que seja útil para treinamento de operadores. / Abstract: Vacuum units for petroleum distillation are studied in this work. Vacuum distillation is employed for heavy petroleum fractions, with large applications on heavy and ultra-heavy crude processing, motivated by difficulties in processing these crudes at atmospheric pressure, due to the boiling range of the compounds in their compositions. These compounds would be easily decomposed if they were not distillated under atmospheric pressure. The products obtained from this unit are used as feedstock for Fluid Catalytic Cracking Unit (FCCU). Two different petroleum crudes were adopted in this work. These petroleum were established and characterized in a simulation environment. Different blends from the oils were considered. As vacuum units in petroleum plants are connected with atmospheric units, both units were simulated in steady state. The atmospheric unit was simulated with the main auxiliary equipment. Products from atmospheric unit were set, and a procedure to set system variables in order to make the products to meet specifications was presented. The conventional design vacuum unit for fuels production was set to be simulated. Procedures to aim convergence of the simulation of this unit were developed. A sensitivity analysis was carried out, analyzing the main variables of the system. Based on it, an optimization procedure in steady state was applied, taking into consideration the convergence bounds set for the sensitivity analysis. The system was converted from steady state to perform a dynamic simulation. The dynamic simulation was carried out with changes in the atmospheric feed flow rate. The establishment of this simulation platform and its availability were very important as well as the results of the simulation, since this is not easily found in the open literature. Moreover, the large complexity of this separation process makes it useful for operator training. / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
7

Valoração dos produtos ultrapesados provenientes da destilação molecular de petróleo / Assessment of petrolem molecular distillation ultra-heavy products

Gordillo Celis, Carlos Alberto 19 August 2018 (has links)
Orientadores: Rubens Maciel Filho, Paula Sbaite Duarte dos Santos / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Química / Made available in DSpace on 2018-08-19T04:58:43Z (GMT). No. of bitstreams: 1 GordilloCelis_CarlosAlberto_M.pdf: 40097706 bytes, checksum: c60604f84094a693629fd3fbc7ee8c2b (MD5) Previous issue date: 2011 / Resumo: Esta dissertação baseia-se na valoração da corrente de destilado e da corrente de resíduo geradas na destilação molecular (DM) do petróleo as quais são obtidas a partir do resíduo de vácuo (RV) proveniente da unidade de destilação a vácuo (UDV). Primeiramente se separou os asfaltenos da corrente ultrapesada do resíduo da DM (RDM), seguido do tratamento com solvente da corrente do destilado da destilação molecular (DDM). Duas amostras de RDM foram utilizadas como matéria prima na separação de asfaltenos, a primeira delas, o RDM obtido a temperatura do evaporador (TDM) de 340°C e, a segunda, o RDM obtido a TDM=280°C. Os asfaltenos separados chamaram-se de A, B e C. O asfalteno "A", separado do RDM TDM=340°C e os asfaltenos "C" e "B" foram separados do RDM TDM=280°C. A comparação das massas molares e da distribuição de massa molar das amostras separadas foi analisada a partir dos dados obtidos por cromatografia de permeação em gel, onde as massas molares medias variam entre 3737 e 4232 Da. Ressalta-se que foi necessário o desenvolvimento de um metodo analítico apropriado para analise de petróleo e asfaltenos por cromatografia de permeação em gel. As amostras de asfaltenos separados da corrente do RDM foram ainda caracterizadas por espalhamento de luz dinâmico, espectroscopia de infravermelho por transformada de Fourier, microscopia eletrônica de varredura e espectroscopia de energia dispersiva de raios-X. Na segunda metade do trabalho, utilizando-se como matéria prima a corrente de DDM TDM=340°C, comparando-se quatro amostras, duas provenientes do mesmo petróleo e mais duas, provenientes de petróleos diferentes. Partindo dessas correntes foi realizada, a desaromatizarão e desparafinação o óleo DDM em uma montagem experimental de bancada operada a pressão atmosférica e temperaturas de -7 a 80°C. O gasto energético envolvido nesse processamento se resumiu ao aquecimento e resfriamento do reator e do sistema de agitação magnético. Com o uso de solventes como, furfural e metil isobutil cetona (MIBC), a corrente de DDM deu origem a quatro óleos com características de óleos básicos, caracterizados e classificados segundo as viscosidades e índices de viscosidades dos mesmos, classificando-se como óleo básico neutro pesado, brilhante e cilindro pesado, dentro dos grupos API I e V. Assim, a valoração das correntes RDM e DDM fecha o ciclo de um grande projeto, que começou com alimentação do RV na UDM e finalizou com aproveitamento das correntes geradas dando valor agregado a esses produtos / Abstract: This dissertation deals with adding value to the distillate and residual streams of the molecular distillation (MD) of petroleum vacuum residua (PVR), PVR being the residual stream of vacuum distillation unit. First of all, asphaltenes were separated from the molecular distillation ultraheavy stream (MDR), followed by the solvent treatment of the molecular distillation distillate stream (MDD). Two samples of MDR were used as raw material for the asphaltene synthesis: the first was obtained at an evaporator temperature during the MD of 340°C; the second, at TDM=280°C. The molar mass and the molar mass distribution of the two samples were obtained from the gel permation chromatography (GPC) analysis. The asphaltenes with molar masses between 3737 to 4232Da were called "A"; "B" and "C". The asphaltene "A" was separated from MDR 340°C and the asphaltenes "B" and "C" were obtained from MDR 280°C. It's important to highlight that it was necessary to develop an analytic method in order to perform the GPC analysis of the samples. The "A"; "B" e "C" samples were characterized by dynamic light scattering (DLS), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). In the second phase of this work, four samples of MDD 340°C, two of them obtained from one petroleum, and the two remaining obtained from different petroleums, were used as raw materials for the deparaffinization and dearomatization processes. The experimental procedure was carried out at atmospheric pressure and temperatures between -7 to 80°C. The energy requirement for this process was related to the heating and cooling of the reactor and to the agitation system. The MDD treatment with furfural and methyl isobutyl ketone (MIBK) produced four different oils showing basic oil characteristics. The oils were classified according to their viscosity and viscosity index into heavy neutral, bright stock and heavy cylinder stock. Besides, they were classified into the I and V API groups. Thereby, the fact of adding value to the MDR and MDD streams closes a bigger project that started with the use of petroleum vacuum residua as feedstock of the molecular distillation process and ended with the better utilization of the distillation waste oil streams / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química
8

Innovativt spillvärmesystem för Cytiva

Ansved, Johannes, Barr, Anton, Baumann, Marcus, Blomander, Matilda, Hedman, Carl, Kempe, Erik, Nerlander, Viktor, Press, Arvid January 2020 (has links)
In this paper different waste heat recovery systems are investigated for Cytiva’s solvent recyclingfacility. Currently steam is used to distill ethanol before cooling it with condenser fans. Thecooling demand varies severely, and peak demand need to be handled with smart energy storagesolutions such as hot water storage tanks or salt storage. Potential heat sinks for the waste heat arelocal heating, heating water for internal use, steam condense and electrical energy generation.Python is used to simulate results with data from Cytiva. The suggested systems are evaluatedbased on yearly performance, savings and environmental impact. A comparison between thedifferent potential systems concludes that none of the investigated solutions can handle the entirecooling demand by itself and redundancy is missing during the summer months. Whenimplemented, the final solution should be a combination of multiple systems.
9

Modellering och analys av potential för värmeåtervinning i industriella destillationsprocesser : En fallstudie hos Cytiva Sweden AB med fokus på energi, utsläpp och ekonomisk lönsamhet.

Maier, Johan January 2024 (has links)
This case study evaluates the potential of recovery and utilization of waste heat from three solvent recovery distillation columns, conducted in collaboration with the biotech company Cytiva Sweden AB. Currently, waste heat from distillation processes is dissipated through conventional air-cooling systems without any heat recovery mechanism. Cytiva are assessing utilizing the waste heat with two distinct methods: using a vapor compression heat pump (HP) in a shared circulating cooling system serving multiple waste heat generating processes and implementing a semi-open mechanical vapor recompression system (MVR) within one of the three distillation processes, thereby substituting the conventional virgin steam-powered reboiler with a waste heat-fed alternative. The study pursues a dual objective. Firstly, it to develops a computational model based on simplified process schematics, fluid flows, and temperatures, encompassing five scenarios, including a baseline scenario devoid of waste heat recuperation or utilization. Two scenarios involving an HP within the cooling system, leveraging waste heat to elevate water temperatures from 50 ⁰C to the requisite 80 ⁰C for subsequent export into a district heating distribution grid. Another scenario integrates an MVR system into one distillation process, while conventionally cooling the remaining waste heat flows. Lastly, a combined scenario incorporates both the HP and MVR systems. Using operational parameters, energy prices, and emissions factors from 2023, the model identifies the optimal alternative based on energy savings, emission reduction, and economic profitability. The combined HP and MVR system emerges as the most favorable option, yielding annual energy savings of 14 500 MWh, a heat export of 9 800 MWh/year generating profits of 4.9 Mkr/year, emissions reductions of 2 000 tonCO2ekv/year, and a yearly total cost savings of 9.9 Mkr. However, the combined system is also the most expensive option. The independent nature of the two systems facilitates ease of installation and operation. These findings provide valuable insights for Cytiva in their efforts to mitigate environmental impact through heat recovery and utilization.
10

Uso da CavitaÃÃo HidrodinÃmica como Alternativa de DesifecÃÃo de Ãgua para Abastecimento Humano / The use of the cavitation hydrodynamics as alternative for the water disinfection for the human supplying

Eliezer Fares Abdala Neto 22 August 2006 (has links)
FundaÃÃo de Amparo à Pesquisa do Estado do Cearà / Relata o uso da cavitaÃÃo hidrodinÃmica como alternativa para a desinfecÃÃo de Ãgua para o abastecimento humano, ampliando a oferta de Ãgua que atenda aos padrÃes de potabilidade. No estado do CearÃ, tendo em vista as condiÃÃes de saneamento precÃrias, fontes de Ãgua utilizadas para abastecimento, sejam superficiais e ou subterrÃneas, tem apresentado um elevado Ãndice de contaminaÃÃo. A Ãgua que à fornecida a populaÃÃo deve estar isenta da presenÃa de microrganismos patogÃnicos. A desinfecÃÃo constitui-se na medida de tratamento que tem como principal meta a eliminaÃÃo dos microrganismos causadores de doenÃas, realizada por meio de agentes fÃsicos e/ou quÃmicos. O cloro tem se destacado como o desinfetante mais difundido, porÃm estudos recentemente publicados trazem a tona que, muitos desses quÃmicos, podem ser danosos aos usuÃrios de Ãguas tratadas e ao ambiente. E que alguns microrganismos causadores de doenÃas, sÃo mais resistente ao tradicional desinfetante cloro do que as bactÃrias do grupo coliformes. Com isso, existe a necessidade de se desenvolver processos de desinfecÃÃo adicionais que poderiam eliminar ou reduzir o uso dessas desinfecÃÃes quÃmicas. Por meio de um levantamento bibliogrÃfico da engenharia aplicada na concepÃÃo da tecnologia de cavitaÃÃo hidrodinÃmica, foram construÃdos protÃtipos para produÃÃo de Ãgua desinfetada atravÃs da cavitaÃÃo hidrodinÃmica; avaliando o potencial de geraÃÃo de cavitaÃÃo hidrodinÃmica atravÃs da eficiÃncia tÃrmica apresentada no protÃtipo; e o estudo da qualidade fÃsico-quÃmica e bacteriolÃgica das Ãguas utilizada no experimento. A final da prototipagem foi possÃvel inativaÃÃo total dos microrganismos observados, coliformes totais e coliformes fecais, presentes na Ãgua de alimentaÃÃo do reator que teve como vazÃo de alimentaÃÃo o valor de 60L/h e potÃncia motriz de 30KW. Apresentando-se como uma alternativa de desinfecÃÃo, caracterizada pela possibilidade de adoÃÃo em plantas de abastecimento de Ãgua individual ou em comunidades de pequeno porte, devido principalmente a nÃo geraÃÃo de subprodutos, mobilidade da vazÃo de operaÃÃo do sistema e o nÃo uso de quÃmicos. / It tells to the use of the cavitation hydrodynamics as alternative for the water disinfection for the human supplying, extending it offers of water that takes care of to the fresh standards. In the state of the CearÃ, in view of the precarious conditions of sanitation, used water sources for supplying, are superficial and or underground, it has presented one raised contamination index. The water that is supplied the population must be exempt of the presence of pathogenic. disinfection consists in the measure of treatment that has as main goal the elimination of the .causing of illnesses, carried through by means of physical and/or chemical agents. The chlorine if has detached as the spread out deodorant more, however studies recently published bring that, many of these chemistries, can be harmful to the users of treated waters and the environment. E that some .causing of illnesses, are more resistant to the traditional deodorant chlorine of what the coliform bacteria of the group. With this, the necessity exists of if to develop disinfection processes you add that they could eliminate or reduce the use of these chemical disinfections. By means of a bibliographical survey of the engineering applied in the conception of the cavitation technology hydrodynamics, they had been constructed to archetypes for water production disinfected through the cavitation hydrodynamics; evaluating the potential of cavitation generation hydrodynamics through the presented thermal efficiency in the archetype; e the study of the quality bacteriological physicist-chemistry and of waters used in the experiment. The end of the test unit was possible death of the observed microorganism, gifts in the water of feeding of the reactor that had as feeding outflow the value of 60L/h and power of 30KW. Presenting itself as an alternative of disinfection, characterized for the possibility of adoption in plants personal of water supply or in communities of small which had mainly transport, not the by-product generation, mobility of the outflow of operation of the system and not the use of chemistries.

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