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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

Controle da injeção de catalisador em uma unidade piloto tipo FCC a frio.

Moura, Alex Elton de 31 August 2015 (has links)
Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-04-15T15:07:33Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação CONTROLE DA INJEÇÃO DE CATALISADOR EM UMA UNIDADE PILOTO TIPO FCC A FRIO.pdf: 3413557 bytes, checksum: 5abbf7dd3a8cab8c21085e585d6282f6 (MD5) / Made available in DSpace on 2016-04-15T15:07:33Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação CONTROLE DA INJEÇÃO DE CATALISADOR EM UMA UNIDADE PILOTO TIPO FCC A FRIO.pdf: 3413557 bytes, checksum: 5abbf7dd3a8cab8c21085e585d6282f6 (MD5) Previous issue date: 2015-08-31 / CNPQ / O Craqueamento Catalítico Fluidizado (FCC) é largamente utilizado no processo de refino do petróleo para transformar hidrocarbonetos de baixo valor comercial em produtos de elevado valor agregado, como gasolina, diesel e GLP. A crescente demanda de combustíveis fósseis, que são recursos não renováveis, requer melhor compreensão do processo e da operação, desafios que tem atraído o interesse da indústria e da academia pelo FCC. Esse processo é bastante competitivo e está em continuo desenvolvimento tecnológico, cujas pesquisas estão divididas em duas grandes linhas: modelos fluidodinâmicos frios e modelos cinéticos. A combinação das informações obtidas nas linhas de pesquisas deve retornar ao processo industrial e garantir a competitividade. Com essa perspectiva, foi construída uma Unidade Piloto a Frio (UPF), no Departamento de Energia Nuclear da UFPE, para a investigação de parâmetros fluidodinâmicos no riser da unidade com auxílio das medidas de transmissão gama. A transmissão gama é requerida como método não intrusivo para medir a distribuição da concentração do catalisador no reator do FCC o riser. Com a operação da UPF realizam-se medidas em tempo real de pressão, vazão, intensidade da radiação, com a condição de que a automação garante que as variáveis do sistema estão sob controle. Este controle é necessário para realização das medidas porque as hipóteses dos modelos matemáticos para simular o escoamento bifásico ar–catalisador de FCC, assumem que o sistema é um leito fluidizado circulando em regime estacionário. Numa unidade piloto como no processo industrial, o controle da injeção de catalisador é um processo de extrema importância, pois a eficiência da reação de craqueamento dos hidrocarbonetos depende da concentração e da distribuição do catalisador no riser. No presente trabalho foi desenvolvido um novo tipo de injetor de sólidos, com desempenho avaliado em função da pressão, intensidade gama e da estabilidade do sistema sob controle automatizado. Os resultados apresentados demonstram que as variáveis do processo, medidas em tempo real, apresentaram a precisão requerida para a operação do sistema em regime estacionário. / The Fluid Catalyst Cracking FCC is a worldwide used process in petroleum refinery aiming to break fossils long carbohydrates chains into more commercial interesting products as gasoline, diesel, GLP. Increasing demand for renewable energy due to time limiting of the fossils sources and also for environmental reasons requires a continuous development and innovation of the FCC process. Such a demand brings technologic and academic efforts in order to keep FCC as a competitive commercial process. Therefore, the research follows two big lines: fluid dynamics and kinetic which for physical models are developed to simulate industrial plants for studying and return the obtained innovation. Looking for such a research perspective a cold model UPF was installed at Nuclear Energy Department of UFPE for fluid dynamic parameters investigation by means of gamma ray transmission measurements. The nuclear nonintrusive technique is required in the riser for the solid concentration distribution measurements. Online measurements of pressure, flow and gamma intensity are carried out during UPF automated operation that is keeping by control a stead state regime. Such operational conditions are assumed in the hypotheses of mathematical models that air-FCC catalyst flow can be simulated as a circulating fluidized bed in a stead state regime. As for a pilot unit in industrial plants the solid injection in riser is very important as the catalyst concentration distribution maps the cracking reactions, therefore, determining process efficiency. In this work a new solid injector was developed, its capability in keeping stable operational conditions was demonstrated by pressure and gamma intensity measurements under automation control.
2

Application of Mixed-Effect Modeling to Improve Mechanistic Understanding and Predictability of Oral Absorption

Bergstrand, Martin January 2011 (has links)
Several sophisticated techniques to study in vivo GI transit and regional absorption of pharmaceuticals are available and increasingly used. Examples of such methods are Magnetic Marker Monitoring (MMM) and local drug administration with remotely operated capsules. Another approach is the paracetamol and sulfapyridine double marker method which utilizes observed plasma concentrations of the two substances as markers for GI transit. Common for all of these methods is that they generate multiple types of observations e.g. tablet GI position, drug release and plasma concentrations of one or more substances. This thesis is based on the hypothesis that application of mechanistic nonlinear mixed-effect models could facilitate a better understanding of the interrelationship between such variables and result improved predictions of the processes involved in oral absorption. Mechanistic modeling approaches have been developed for application to data from MMM studies, paracetamol and sulfapyridine double marker studies and for linking in vitro and in vivo drug release. Models for integrating information about tablet GI transit, in vivo drug release and drug plasma concentrations measured in MMM studies was outlined and utilized to describe drug release and absorption properties along the GI tract for felodipine and the investigational drug AZD0837. A mechanistic link between in vitro and in vivo drug release was established by estimation of the mechanical stress in different regions of the GI tract in a unit equivalent to rotation speed in the in vitro experimental setup. The effect of atropine and erythromycin on gastric emptying and small intestinal transit was characterized with a semi-mechanistic model applied to double marker studies in fed and fasting dogs. The work with modeling of in vivo drug absorption has highlighted the need for, and led to, further development of mixed-effect modeling methodology with respect to model diagnostics and the handling of censored observations.
3

Contribution à l'étude des parois complexes végétalisées : évaluation de la performance énergétique globale en climat tropical humide / Contribution to the Vegetalised Complex Partition study (VCP) : Energetic performance evaluation under a tropical humid climate

Jean, Aurélien 08 December 2015 (has links)
En matière de consommation énergétique mondiale, l'augmentation est indiscutablement la tendance actuelle. Conformément au contexte énergétique international, l'île de La Réunion doit faire face à une demande énergétique croissante. Après analyse de la répartition de ces besoins, la régulation thermique du bâti apparaît être l'un des postes les plus énergivores. Afin de réduire l'importance de ce poste, la solution présentement proposée consiste a végétaliser la structure afin d'en réduire la surchauffe. Le présent article est une introduction vulgarisée au domaine des parois complexes végétalisées (PCV). Afin d'accréditer cette prétention, la notion de toiture végétalisée, leurs utilisations, ainsi que les différentes modifications quelles induisent y sont définies. L'illustration des propos est permise par l'application d'un cas d'étude concret, celui d'une utilisation sur l'île de La Réunion. Cette dernière permettant de définir divers impacts du système dans ces conditions. / The aim of this article is to present a vulgarized introduction to the vegetated complex partitions field, called VCP. To reach this goal, the green roof notions, their uses and implications are defined. The theory is illustrated by a Reunion Island case study, which allows to list several impacts of the green walls utilization.
4

台灣電力市場用戶群代表制度之研究 / Analysis of aggregator systems for the Taiwan electricity market

洪穎正, Hung, Ying Cheng Unknown Date (has links)
本研究針對先進國家「用戶群代表」制度之政策與法規進行探討,並進一步探討如何施行於台灣電力市場。首先定義並解釋「用戶群代表」涵意後,整理出先進國家(包含美國、歐盟、德國、澳洲、韓國五個地區與EnerNOC、Comverge、CPower、OhmConnect四個公司)的用戶群代表商業模式案例,藉由文獻分析與個案研究,觀察先進國家政策方向與用戶群代表市場定位差異。同時,本研究由我國用戶群代表相關制度法規,探討用戶群代表於我國電力市場實施之適法性。此外,本研究根據文獻回顧整理出發展用戶群代表制度的關鍵成功因素,並詳細探討我國當前條件是否適合發展。最後針對政府與台電、產業界、學術界、電力用戶的不同角度,提出可行的政策法規建議。 / This thesis explores the policies and regulations of aggregator systems in advanced countries and explores how to implement aggregator system in Taiwan electricity market. In order to achieve this objective, we first define and elaborate the meanings of aggregator. Then, experience and case studies of USA, European Union, Germany, Australia and Korea are studied. In addition, business models of four aggregators, EnerNOC, Comverge, CPower and OhmConnect are presented. Furthermore, we examine current related regulations of an aggregator in Taiwan electricity market for feasibility analysis. In addition, this study summarizes the key success factors of the development of aggregator systems according to the literature review, and discusses in detail whether Taiwan's current conditions are suitable for development. Finally, market models and policy regulations in relation to the aggregator are recommended.

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