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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.
21

Modélisation des équilibres entre phases et simulation de la distillation des eaux-de-vie en vue d’une meilleure compréhension du comportement des composés volatils d’arôme / Modeling of phase equilibria and simulation of spirits distillation for a better understanding of volatile aroma compounds behavior.

Puentes Mancipe, Cristian 13 December 2017 (has links)
La qualité des eaux-de-vie est un paramètre associé à la composition en composés volatils d’arôme. Cette composition résulte de la combinaison de différents facteurs dont la nature et le traitement des matières premières, mais surtout des transformations ayant lieu lors des phases de fermentation, distillation et, dans la plupart de cas, vieillissement.La distillation est une opération de séparation pratiquée depuis des millénaires, avec une technologie assez mature. Cependant, dans le domaine des eaux-de-vie, elle s’appuie essentiellement sur des connaissances empiriques. L’objectif de ce doctorat fut de contribuer à une meilleure compréhension du comportement des composés volatils d’arôme au cours de différents modes de distillation et de fournir des bases scientifiques à la conduite des unités par le biais de modules de simulation. L’attention a été portée sur la distillation d’Armagnac et de Calvados dans des colonnes multiétagées en régime stationnaire.Les modules de simulation ont été construits avec le logiciel ProSimPlus®. La première partie des travaux a été consacrée à l’acquisition de données d’équilibre liquide-vapeur des composés volatils d’arôme en milieu hydroalcoolique pour l’identification du modèle NRTL, en suivant trois approches complémentaires : recherche dans la littérature, détermination expérimentale et prédiction théorique avec les modèles UNIFAC et COSMO. Grâce à la connaissance acquise sur les volatilités relatives par rapport à l’éthanol et à l’eau, les composés volatils d’arôme ont pu être classés en trois groupes : composés légers, composés intermédiaires et composés lourds. La deuxième partie des travaux a porté sur la construction et la validation des modules de simulation, après réconciliation des données issues de la caractérisation expérimentale des unités de distillation. Cette investigation démontre que la simulation est un outil d’ingénierie performant dans le domaine des eaux-de-vie. Les résultats de la simulation ont permis d’affiner la classification des composés intermédiaires en trois catégories supplémentaires selon leur profil de concentration dans la colonne et leur taux de récupération dans le distillat. Enfin, cet outil a mis en évidence que certains paramètres opératoires, notamment l’augmentation de la teneur en éthanol du distillat ainsi que l’extraction de queues, favorisent la séparation préférentielle de certaines espèces de volatilité faible ou intermédiaire par rapport à l’éthanol. / The quality of spirits is a parameter related to the composition of volatile aroma compounds. This composition results from the combined production process of raw material extraction, subsequent fermentation, distillation and, in many cases, ageing.Distillation is a very old and the most important industrial separation technology. However, in spirits production, this operation relies essentially on empirical knowledge. The aim of this PhD was to contribute to a better understanding of the volatile aroma compounds behaviour in spirits distillation and to provide a scientific basis for the process through computer simulation. The study was focused on Armagnac and Calvados production by continuous multistage distillation.The simulation modules were built using the software ProSimPlus®. The first part of this research was dedicated to the acquisition of vapor-liquid equilibrium data of the volatile aroma compounds in ethanol-water solutions, in order to estimate the binary interaction parameters of the NRTL model.Three complementary approaches of data acquisition were used: literature compilation, experimental measurements and predictions with UNIFAC and COSMO models.According to their relative volatilities with respect to ethanol and water, the volatile aroma compounds can be classified in three groups: light compounds, intermediary compounds and heavy compounds. The second part of this research dealt with the creation and validation of simulation modules, by using reconciled experimental data from the distillation units. The results prove that simulation is a powerful tool in spirits distillation. The simulation data enables a more precise classification of the intermediary compounds in three categories, by considering their composition profiles in the distillation column and their recovery ratios from feed to distillate. Finally, the analysis of some operating parameters, including ethanol concentration in the distillate as well as tails extractions, demonstrates that the distillate composition can be modified by virtue of a selective separation of intermediary and heavy compounds with respect to ethanol.
22

An adaptive modeling and simulation environment for combined-cycle data reconciliation and degradation estimation.

Lin, TsungPo 26 June 2008 (has links)
Performance engineers face the major challenge in modeling and simulation for the after-market power system due to system degradation and measurement errors. Currently, the majority in power generation industries utilizes the deterministic data matching method to calibrate the model and cascade system degradation, which causes significant calibration uncertainty and also the risk of providing performance guarantees. In this research work, a maximum-likelihood based simultaneous data reconciliation and model calibration (SDRMC) is used for power system modeling and simulation. By replacing the current deterministic data matching with SDRMC one can reduce the calibration uncertainty and mitigate the error propagation to the performance simulation. A modeling and simulation environment for a complex power system with certain degradation has been developed. In this environment multiple data sets are imported when carrying out simultaneous data reconciliation and model calibration. Calibration uncertainties are estimated through error analyses and populated to performance simulation by using principle of error propagation. System degradation is then quantified by performance comparison between the calibrated model and its expected new & clean status. To mitigate smearing effects caused by gross errors, gross error detection (GED) is carried out in two stages. The first stage is a screening stage, in which serious gross errors are eliminated in advance. The GED techniques used in the screening stage are based on multivariate data analysis (MDA), including multivariate data visualization and principle component analysis (PCA). Subtle gross errors are treated at the second stage, in which the serial bias compensation or robust M-estimator is engaged. To achieve a better efficiency in the combined scheme of the least squares based data reconciliation and the GED technique based on hypotheses testing, the Levenberg-Marquardt (LM) algorithm is utilized as the optimizer. To reduce the computation time and stabilize the problem solving for a complex power system such as a combined cycle power plant, meta-modeling using the response surface equation (RSE) and system/process decomposition are incorporated with the simultaneous scheme of SDRMC. The goal of this research work is to reduce the calibration uncertainties and, thus, the risks of providing performance guarantees arisen from uncertainties in performance simulation.
23

[en] MASS BALANCE DATA RECONCILIATION OF THE URUCU- MANAUS GAS PIPELINE / [pt] RECONCILIAÇÃO DE DADOS DO BALANÇO DE MASSA NO GASODUTO URUCU-MANAUS

GISELE DE OLIVEIRA BARRETO 06 May 2016 (has links)
[pt] Se por um lado à privatização do setor de energia, que induz acirrada concorrência, tem estimulado a inovação tecnológica e a adoção de mecanismos de incentivos à eficiência operacional, a regulação do mercado introduz mecanismos de controle requerendo maior responsabilidade no uso consciente da energia de sorte a assegurar a eficiência energética e a proteção ambiental. Pressões de organizações ambientalistas internacionais e a crescente demanda por energia explicam a tendência mundial pelo uso de combustíveis fósseis mais limpos. O baixo nível de emissões e resíduos associados ao processo de combustão de gás natural qualifica esta commodity energética como um elemento estratégico para integrar a matriz energética de organizações e países comprometidos com a sustentabilidade global. O impacto econômico associado à medição de gás natural exige uma otimização do controle do balanço de massa no sistema de entrega. A aplicação da Metodologia de Reconciliação de Dados constitui o objetivo deste trabalho. A técnica provou ser uma ferramenta eficaz para a avaliação do balanço de massa em um gasoduto durante o período de operação associado ao transporte de gás natural. A natureza intrínseca do seu algoritmo de cálculo, que leva em conta a redundância nas medições, qualifica a metodologia para aumentar a confiabilidade da medição assim reduzindo a incerteza individual associada a cada grandeza física capaz de interferir na medição e identificar erros grosseiros. Fundamentado na avaliação metrológica do balanço de massa de um gasoduto brasileiro, os resultados do estudo permitem discutir a adequação da técnica proposta de reconciliação de dados. Dentre as conclusões do trabalho, foi possível mostrar que o uso da técnica de tratamento dos dados do gás não contado (unaccounted for gas) pode atingir valores inferiores a 0,3 porcento, comparando-se, assim, à tolerância preconizada em nível internacional. / [en] If on the one hand, privatization of the energy sector, which induces keen competition, has stimulated technological innovation and the adoption of incentive mechanisms for operational efficiency, regulation of the market introduces control mechanisms requiring greater responsibility in the conscious use of energy so as to ensure energy efficiency and environmental protection. Pressure from international environmental organizations and the growing demand for energy, explain the worldwide tendency for the use of cleaner fossil fuels. The lower levels of emissions and residues associated with the combustion process of natural gas classify this energy commodity as a strategic element to enter into the energy matrix of organizations and countries committed to global sustainability. The economic impact associated with the measurement of natural gas, demands optimization in controlling the mass balance in the delivery system. Application of the Data Reconciliation Methodology constitutes the objective of this work. The technique proved to be an efficient tool for the evaluation of the mass balance in a gas pipeline for the period of operation associated with the transport of natural gas. The intrinsic nature of its calculation algorithm, which takes into account the redundancy of measurements, qualifies the methodology to increase the confidence of measurement, thereby reducing the individual uncertainty associated with each physical volume capable of interfering with the measurement and identify gross errors. Based on the metrological evaluation of the mass balance of a Brazilian pipeline, the results of the study enable discussion on the adequacy of the data reconciliation technique proposed. Among the conclusions of the work, it was possible to demonstrate that the use of the technique in treating the data of unaccounted for gas, could achieve values lower than 0.3 percent, thereby comparable with the tolerances advocated at international level.
24

Reconciliação dinâmica de dados baseada em estimadores em uma malha de controle MPC / Dynamic data reconciliation based on estimators in a MPC control loop

Silva, Guilherme Moura Afonso da 27 April 2017 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The data reconciliation in process control is extremely important regarding the industries because from this it is possible to obtain a greater efficiency in the performance in industrial process control meshes aiming at a lower cost and a higher quality of the product. In this work we approach data estimation techniques for the implementation of an online dynamic data reconciliation system in order to reduce the noise and the measurement uncertainties that are submitted in the process variables. The techniques used here are: the Kalman Filter, the Preditor-Corrector DDR Algorithm, the Moving Horizon Estimator (MHE) and the Constrained Extended Kalman Filter (CEKF). The analysis is performed by applying the dynamic data reconciliation system in a simulated process, characteristic of the chemical industry, operating under MPC (Model Predictive Control). The performance of the MPC controller is also enhanced by the use of the reconciled data in the feedback control loop. / A reconciliação de dados em controle de processos é extremamente importante no que diz respeito às indústrias, pois a partir dessa é possível obter uma maior eficiência no desempenho em malhas de controle de processos industriais visando à minimização dos custos e maximizando a qualidade do produto. Neste trabalho abordam-se técnicas de estimação de dados para a implementação de um sistema de reconciliação dinâmica de dados on-line a fim de reduzir os ruídos e as incertezas de medições a que estão submetidas às variáveis do processo. As técnicas aqui empregadas são: o Filtro de Kalman, o Algoritmo DDR Preditor-Corretor, o Estimador de Horizonte Móvel (MHE) e o Filtro de Kalman Estendido com Restrições (CEKF). As análises são efetuadas aplicando o sistema de reconciliação dinâmica de dados em um processo simulado, característico da indústria química, operando sob controle preditivo (MPC). Também é efetuado o aprimoramento no desempenho do controlador MPC utilizando os dados reconciliados na malha de realimentação do controlador.
25

Aplikace pokročilých regresních modelů / ADVANCED REGRESSION MODELS

Rosecký, Martin January 2018 (has links)
This thesis summarizes latest findings about municipal solid waste (MSW) modelling. These are used to solve multivariable version of inverse prediction problem. It is not possible to solve such problem analytically, so heuristic framework using regression models and data reconciliation was developed. As a side product, models for MSW modelling using PCA (Principal Component Analysis) and LM (Linear Model) were created. These were compared with heuristic model called RF (Random Forest). Both of these models were also used for per capita MSW modelling. Theoretical parts about generalized linear models, data reconciliation and nonlinear programming are also included.
26

Vyrovnání provozních dat v energetických procesech / Data reconciliation of energy processes

Nováček, Adam January 2015 (has links)
This thesis is focused on problem data reconciliation of measurements. The objective of this thesis was reconciled measured value from electric drum dryer to suit exactly to the mathematical model of drying. For solution was used nonlinear data reconciliation with constrained nonlinear optimization. The entire calculation is processed in programme MATLAB and outputs are graphs of reconciled values of measurement on dryer such as inlet and outlet temperature and humidity, differential pressure of exhaust moisture air, weight of laundry, atmospheric pressure and electric supply. Achieved solution can by characterized by an amount of evaporated water. Weight of wet and dry laundry are 27,7 kg a 17,7 kg. The calculated amount of evaporated water from measurements was almost 18,8 kg. With reconciled measurements it was 9,7 kg. Goals of the thesis were found more realistic values.
27

[en] DATA RECONCILIATION AND GUARD BANDS APPLIED TO THE ESTABLISHMENT OF SULFUR LIMITS IN FUELS FOCUSING ON MEETING SPECIFICATIONS / [pt] RECONCILIAÇÃO DE DADOS E BANDAS DE GUARDA APLICADAS AO ESTABELECIMENTO DE LIMITES DE ENXOFRE EM COMBUSTÍVEIS COM FOCO NO CUMPRIMENTO DAS ESPECIFICAÇÕES

ANA CAROLINA HERMOGENES DE MATOS 12 January 2023 (has links)
[pt] É uma prática operacional comum que as refinarias trabalhem de forma otimizada e produzam diesel e gasolina com fração mássica de enxofre conforme o limite da especificação. No entanto, quando esse parâmetro de qualidade é analisado pelas refinarias e, após as operações de transferência, é reanalisado pelos terminais de armazenamento, esses resultados de medição nem sempre atendem à especificação. Para evitar disputa entre produtores e consumidores sobre o cumprimento da especificação é necessário que haja uma margem mais segura dentro da avaliação da conformidade desses produtos. Este trabalho apresentou uma nova metodologia que utiliza da Reconciliação de Dados em conjunto com o conceitos de bandas de guarda para determinação de novos limites de tolerância de propriedades críticas, como o enxofre, em alguns combustíveis, com base na reprodutibilidade, na diferença entre as médias de todos os resultados aceitáveis de cada laboratório e nas especificações brasileiras. Essa abordagem alternativa pode ser utilizada para evitar disputas entre fornecedores e clientes (Oliveira e Aguiar, 2019). Em conjunto com a RD foram utilizados os conceitos de regras de decisão com as definições das bandas de guarda, apresentados pelo Guia Eurachem/CITAC, 2021. Na presente pesquisa, foi visto que utilizando restrições de processo e medições redundantes, o valor reconciliado (resultado final) apresenta melhores valores experimentais, além disso a incerteza reconciliada é minimizada em relação às incertezas que foram calculadas experimentalmente. / [en] It is an operational practice that refineries (here producers) work in an optimized way and produce diesel and gasoline with a mass fraction of sulfur close to the specification. However, when this quality parameter is analyzed by refineries and, later, after custody transfer operations, it is re-analyzed by storage terminals (here called consumers), these measurement results do not always meet the specification. This study proposes a new methodology based on data reconciliation connected to the guard bands concept to establish upper acceptance limits for producers offering a comfortable giveaway to consumers. From the minimized reconciled expanded uncertainties, process model constraints, and the upper specification limits, the upper acceptance limits for the producers were optimized to ensure that the reconciled values meet the specification. Consumer and producer risks and histograms were calculated. Validation data sets proved that the proposed methodology could be applied because all the reconciled values comply with the specifications.

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