Submitted by Deyse Queiroz (deysequeirozz@hotmail.com) on 2018-05-16T14:53:03Z No. of bitstreams: 1 POTÍ OLIVEIRA CORTÊZ DOSTA - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 1109832 bytes, checksum: b9946c27427ba9fe3bba90b7b91d41cd (MD5) / Made available in DSpace on 2018-05-16T14:53:03Z (GMT). No. of bitstreams: 1 POTÍ OLIVEIRA CORTÊZ DOSTA - DISSERTAÇÃO PPGSA PROFISSIONAL 2015..pdf: 1109832 bytes, checksum: b9946c27427ba9fe3bba90b7b91d41cd (MD5) Previous issue date: 2015-07 / Em busca de alternativas para o aproveitamento de resíduos do abate animal foi estudado um protótipo de reator contínuo de custo-benefício acessível para uso popular na agroindustrial local, com fins de produzir biocombustível líquido. Bem como, avaliação experimental por meio deste aproveitamento com o sebo, adquirido nos abatedouros públicos e caseiros de Catolé do Rocha-PB, utilizando dois tipos de métodos, a saber: hidroesterificação e craqueamento térmico catalítico. O sistema foi construído em escala de laboratório, composto por materiais metálicos de aço inox e algumas conexões de silicone. O sistema foi composto por reator, trocador de calor e uma bomba periférica comercial de 1/4CV. O aquecimento foi efetuado por chama a gás, o fluxo, a temperatura e pressão foram monitoradas. O reator foi manufaturado resultando em um volume de 687,22 mL. A avaliação experimental do sistema proposto foi realizada introduzindo gordura animal, a qual foi extraída do sebo por duas técnicas, chapa elétrica e autoclave, buscando investigar o melhor rendimento. A autoclave foi mais significativa (75,7%). Posteriormente, a síntese do biocombustível com o método da hidroesterificação adotando o referido sistema, apresentou não conformidade operacional na conexão da saída do reator, visto que estas foram rompidas, devido à formação de vapor internamente, ocasionando retorno da mistura aquecida para a conexão com a bomba periférica. Esperava-se atingir temperatura de 260 ºC e pressão de 3bar, mas não foram atingidas. A segunda tentativa foi realizada buscando se atingir 200 ºC a 2bar, porém aos 157 ºC houve nova formação de refluxo. Diante deste fato, o sistema foi modificado, entre o reator e o trocador de calor a fim de se realizar um craqueamento termocatalítico, utilizando dois tipos de catalisadores independentemente, o carbonato de cálcio e a ferrita de níquel. Adotou-se a razão de 1:10 de catalisador/gordura injetados no sistema, pressão ambiente e temperatura acima de 600 ºC. Este método revelou bom funcionamento para o sistema idealizado, mas, ainda necessita ser aprimorado, em virtude do rendimento do bio-óleo ter sido inferior ao citado em literatura. Comparando a síntese entre os catalisadores o bio-óleo de carbonato de cálcio obteve melhor rendimento (49,51%), menor índice de acidez (1,45 mgKOH/g) porém o perfil térmico sugeriu maior presença de ácidos graxos combinados, moléculas de diacilglicerídeos e triacilglicerídeos. Já com ferrita de vii níquel teve menor rendimento 32,22%, maior índice acidez (5,36 mgKOH/g) e perfil térmico característico de apenas uma decomposição térmica sugerindo uma melhor ação catalítica. Ambos os bio-óleos apresentaram índice de acidez acima das normas da ANP. / In search of alternatives to recovery waste to animals slaughter, was studied a prototype of affordable continuous reactor for public use and local agribusiness, for purposes of producing liquid biofuels. As well, through the experimental evaluation of tallow use, acquired in public and homemade slaughterhouses Catolé Rocha-PB, using two types of methods, namely: hidroesterification and catalytic thermal cracking. The system was built on a laboratory scale, composed of metallic materials of stainless steel and some silicone connections. The system is composed of reactor, heat exchanger and pumps a commercial peripheral 1/4CV. Heating was affected by flame gas, and both flow with temperature and pressure were monitored. The reactor was manufactured resulting in a volume of 687.22 mL. The experimental evaluation of the system was carried out by introducing animal fat, which was extracted from tallow by two techniques, plates and autoclave techniques in order to investigate the best performance. The autoclave was more significant (75.7%). Thereafter, the biofuels synthesis was performed in the system, initially with the method of hidroesterification, in which one cannot observe operating line of the system, the reactor outlet connection, since these were broken due to formation of steam internally, causing returning the mixture heated for connecting to peripheral pump. Was expected reach 260 °C temperature and 3bar pressure, without success. A second attempt was carried out in order to achieve 2bar to 200 ºC, but at 157 ºC was new line of reflux. Given this fact, the system was modified between the reactor and the heat exchanger in order to hold a thermo catalytic cracking using two types of catalysts, independently, calcium carbonate and nickel ferrite. Adopted the ratio of 1:10 catalyst/fat injected into the system, ambient pressure and temperature above 600 °C. This method showed good run for the idealized system, but still needs to be improved since the yield of bio-oil was lower than that cited in the literature. Comparing the synthesis of the catalysts as calcium carbonate bio-oil obtained better yield (49.51%), acidity index (1.45 mgKOH/g), however the thermal profile suggested greater presence of fatty acids combined, diacilglicerídeos and triacilgerídeos molecules. Already with nickel ferrite had lower yield (32.22%), higher acidity index (5.36 mgKOH /g) and ix characteristic thermal profile of just one thermal decomposition suggesting a better catalytic action. Both bio-oils had acidity index above the standard of the ANP.

Orientadores: Maria Regina Wolf Maciel, Henry França Meier, Antonio Andre Chivanga Barros / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-08T19:43:12Z (GMT). No. of bitstreams: 1 Wiggers_VinicyusRodolfo_D.pdf: 8765117 bytes, checksum: 4f3088b3ee50ec116b65b9bb63658c4a (MD5) Previous issue date: 2007 / Resumo: A necessidade de diversificação e gradual substituição das atuais fontes de energia demandam o estudo e desenvolvimento de tecnologias alternativas que sejam capazes de substituir os combustíveis fósseis e minimizar os impactos ambientais causados por esses. Nesse sentido, a biomassa apresenta-se como alternativa tecnológica dada sua potencial capacidade de produção de combustíveis líquidos e gasosos capazes de substituírem o petróleo. Devido aos fatores econômicos e ambientais a utilização de óleos vegetais e gorduras residuais constituem-se numa importante fonte de matéria-prima e objeto de investigação científica presente nesse trabalho, em nível de doutorado. Uma unidade em escala de bancada, com capacidade de produção de até l0 kg/h, foi projetada, construída e utilizada para a execução de experimentos com óleo de soja degomado e óleo de fritura, com o intuito de se avaliar, tecnicamente, a possibilidade de produção de biocombustíveis. Os experimentos seguiram um planejamento experimental variando-se parâmetros de processo e os produtos gerados foram submetidos tanto à análise química por técnicas de cromatografia para determinação da composição em termos de números de carbonos, do poder calorífico superior quanto a procedimentos de determinação das características de destilação dos produtos. Os resultados obtidos com a análise dos produtos possibilitam a produção de biocombustíveis com características similares à,s da gasolina e do diesel, derivados de petróleo. / Abstract: The neeessity of diversifieating and substituting the aetual energy' s sourees leads to studies and altemative teehnology developments able to substitute the fossil fuels and reduee the environment impaets. In this way, the biomass appears as a potential altemative souree of solids, gases and liquids fuels able to substitute the petroleum. Due to environrnental and eeonomie faets, the use of vegetable oils and waste fatty acids are an important souree of feedstoek and the scientifie study of this work. A beneh se ale unit, with 10 kglh eapacity, was projeeted, built and used to experiments runs with soybean oil and eooking oil to investigate the teehnieal possibility of produetion of biofuels. The experiments were done following an experimental plan by ehanging proeess parameters and the products were ehemieal analyzed by ehromatography to determine the eomposition in terms of earbón numbers and heat power. A methodology to determine the distillation eharaeteristics of the produets leads to the possibility of produetion of biofuels like the fuels from petroleum. / Doutorado / Desenvolvimento de Processos Químicos / Doutor em Engenharia Química

Heat of hydration is a property of Portland cement and a direct result of the chemical reaction between cement and water. The amount of heat released is dependent upon the cement mineralogical composition, curing temperature, water to cement ratio, and cement fineness. High temperature resulting from heat of hydration (thereon referred to as HOH) of cement can affect the hydration process, and consequently the kinetics of development of the mechanical properties of concrete. One of the main reasons triggering the interest in HOH of cement is its implication in thermal cracking of concrete. The high temperature gradient between the inner core and the outer surface of a concrete element is known to result in large tensile stresses that may exceed tensile strength, thus leading to early–age thermal cracking in mass concrete. This dissertation initially addresses accurately predicting the heat of HOH of Portland cement at seven days based on the heat flow data collected from isothermal calorimetry for a time interval of 0-84 h. This approach drastically reduces the time required to identify the seven day HOH of Portland cement. The second part of this study focuses on cement fineness and its critical role on the heat generated by Portland cement during hydration. Using a matrix of four commercially available Portland cements, representing a wide range of mineralogical composition, and subjecting each of the as-received cements to several grinding increments, a linear relationship was established between cement fineness and heat of hydration. The effect of cement fineness and mineralogical composition on HOH of Portland cement was then related through a mathematical expression to predict the HOH of Portland cement based on its mineralogical composition and fineness. Three expressions were proposed for the 1, 3 and 7 day HOH. The findings indicate that the equations developed, based on cement main phase composition and fineness, can be used to identify cements with high heat of HOH that may cause thermal cracking in mass concrete elements. Also, the equations can be used to correlate the HOH with the other properties of Portland cement for quality control and prediction of chemical and physical properties of manufactured Portland cement and concrete. Restrained shrinkage experiments results on mortar specimens prepared with cements of variable phase composition and fineness indicate that interaction of C3A and sulfate source is the prime phenomenon followed by cement fineness as the second main factor influencing concrete cracking. In order to minimize this effect, the third part of this study focused on studying alternatives that can lower the heat generated by concrete on hydration through the incorporation of nanomaterials; namely, graphene nanoparticles. The results indicate that incorporation of graphene a as replacement for Portland cement improves thermal diffusivity and electrical conductivity of the cement paste. Consequently, the use of graphene can trigger improvement of the thermal conductivity of concrete elements thus reducing the cracking potential of concrete. Measurements of HOH of graphene-cement paste, at w/c=0.5, using isothermal conduction calorimetry, indicate that incorporation of graphene up to 10% increases the length of the induction period while reduces the magnitude of the alite main hydration peak due to the filler effect. Furthermore, increasing the w/c ratio from 0.5 to 0.6 and graphene content from 1 % to 10% (as a partial replacement of cement) increases the 7 day HOH of Portland cement by 50 J/g. Isothermal conduction calorimetry heat flow curves show that incorporation of graphene particles up to 10% does not have significant effect on interaction of aluminates and sulfates sources since the time of occurrence of the C3A sulfate depletion peak is not affected by graphene substitution up to 10%. Full factorial statistical design and analysis conducted on compressive strength data of mortar specimens prepared at two w/c ratios, using cements of different finenesses and graphene content indicates that the quantity of graphene and the physical interaction due to variable w/c, graphene and cement fineness, have the smallest P-value among all the samples, representing the most significant impact on compressive strength of mortar samples. It appears that in graphene cement paste composites, addition of 1% graphene results in 21% reduction of Young’s modulus. Increasing the graphene content from 1% to 5% and/or 10% does not show significant effect on Young’s modulus. Similar trends can be observed in the hardness of graphene cement paste samples. In conclusion, partial replacement of Portland cement with graphene nanoparticles in concrete mixtures is a good alternative to lower the cracking potential in mass concrete elements.

Student Number : 9900772K - MSc research project - School of Civil and Environmental Engineering - Faculty of Engineering and the Built Environment / The hydration of cement is an exothermic reaction, which begins almost immediately upon contact with water. This produces a large amount heat that subsequently raises the temperature of the concrete mixture, creating a temperature gradient across the member. The temperature rise associated with hydration induces thermo-mechanical stresses. These stresses can cause damage to the structure, affecting the durability and in extreme cases the functionality of the structure. If the maximum rate of heat evolution experienced can be minimised through the selection of the constituents of a concrete mixture, then the thermal stresses that develop in the concrete can be reduced. The main aim of this research is to develop a knowledge of how the heat evolution characteristics of concrete are affected by changing certain concrete mixture parameters and ingredients. The focus is on the addition of three different cement extenders and varying the water/cement ratio. This will be a step towards the development of a model for predicting the thermal properties of concrete. As a part of this investigation, a prediction model for the change in heat rate in concrete was developed. The model is intended to predict the contribution of the individual clinker crystallographic phases in cement and the heat liberated in concrete during hydration.

The dependence on oil and the fact that petroleum conventional reservoirs are becoming depleted direct attentions toward unconventional-and harder to access-reservoirs. Among those, heavy and extremely heavy oil reservoirs and tar sands form a considerable portion of all petroleum resources. Conventional thermal and thermocatalytic refining methods are not affordable choices in some cases, as they demand a considerable energy investment. On the other hand, electron irradiation, as a novel technology, provides more promising results in heavy oil upgrading. Electron irradiation, as a method of delivering energy to a target molecule, ensures that most of the energy is absorbed by the molecule electronic structure. This leads to a very efficient generation of reactive species, which are capable of initiating chemical reactions. In contrast, when using thermal energy, only a small portion of the energy goes into the electronic structure of the molecule; therefore, bond rupture will result only at high energy levels. The effect of electron irradiation on different heavy petroleum fluids is investigated in this study. Radiation-induced physical and chemical changes of the fluids have been evaluated using different analytical instruments. The results show that high energy electron particles intensify the cracking of heavy hydrocarbons into lighter species. Moreover, irradiation is seen to limit any post-treatment reactions, providing products of higher stability. Depending on the characteristics of the radiolyzed fluid, irradiation may change the distribution pattern of the products, or the radiolysis process may follow the same mechanism that thermal cracking does. In addition to that, we have studied the effectiveness of different influencing variables such as reaction temperature, absorbed dose values, and additives on radiolytic reactions. More specifically, the following subjects are addressed in this study: *Radiation?induced chain reactions of heavy petroleum fluids *Complex hydrocarbon cracking mechanism *High and low temperature radiolysis *Synergetic effects of different chemical additives in radiolysis reactions *Time stability of radiation products

Submitted by Johnny Rodrigues (johnnyrodrigues@ufcg.edu.br) on 2018-04-30T16:15:44Z No. of bitstreams: 1 TALLES CAIO LINHARES DE OLIVEIRA - DISSERTAÇÃO PPGEQ 2014..pdf: 2048638 bytes, checksum: 8906a39fa89dff7c77323f97499594a3 (MD5) / Made available in DSpace on 2018-04-30T16:15:44Z (GMT). No. of bitstreams: 1 TALLES CAIO LINHARES DE OLIVEIRA - DISSERTAÇÃO PPGEQ 2014..pdf: 2048638 bytes, checksum: 8906a39fa89dff7c77323f97499594a3 (MD5) Previous issue date: 2014-09 / CNPq / O monômero cloreto de vinila (MVC), matéria prima usada para a obtenção do policloreto de vinila (PVC), é produzido comercialmente em larga escala através da decomposição térmica do 1,2-dicloroetano (EDC) em um reator tubular inserido em um forno industrial. O PVC possui aplicações que vão desde produtos médico-hospitalares e embalagens para alimentos até peças de alta tecnologia como as usadas em equipamentos espaciais. O principal problema enfrentado na operação é a formação de uma camada de coque no interior do reator que limita o tempo de operação. O presente trabalho consiste no desenvolvimento de modelos matemáticos para a previsão do comportamento de um reator de craqueamento térmico de EDC. Um total de três modelos foram formulados, o primeiro modelo serviu para estruturação do algoritmo e para a análise geral da metodologia usada. No segundo modelo uma cinética reacional mais complexa envolvendo composto estáveis e radicais foi implementada, a deposição de coque foi considerada o que possibilitou estimar o seu impacto no tempo de produção e nas variáveis do processo como: pressão, temperatura e conversão. O último modelo foi desenvolvido utilizando técnicas de fluidodinâmica computacional (CFD) e forneceu as distribuições na direção radial e ao longo do reator para as variáveis do processo. Os resultados obtidos de todos os modelos estão em concordância com dados industriais disponíveis. Os modelos I e II podem ser usados para realização de testes no processo sem a necessidade de utilização de unidade piloto e como ponto de partida para a otimização nos fornos de craqueamento, enquanto o modelo em CFD pode contribuir para estudo de melhorias de projeto deste tipo de reator. / The vinyl chloride monomer (MVC) raw material used to obtain the polyvinyl chloride (PVC), is commercially produced on a large scale by thermal decomposition of 1,2dichloroethane (EDC) inserted into a tubular reactor in an oven industrial. PVC has applications ranging from medical products and food containers to high-tech parts like those used in space equipment. The main problem faced in the operation is the formation of a layer of coke inside the reactor which limits the time of operation. The present work is the development of mathematical models for predicting the behavior of reactor thermal cracking of EDC. A total of three models were formulated, the first model was used to structure the algorithm and the overall analysis of the methodology used. In the second model a more complex reaction kinetics involving radicals and stable compound was implemented, coke deposition was found which allowed to estimate their impact on production time and the process variables such as pressure, temperature and conversion. The last model was developed using computational fluid dynamics (CFD) and provided the distributions in the radial direction and along the reactor for the process variables. The results of all the models are in agreement with industrial data available. Models I and II can be used for testing the process without the need of using pilot unit and as a starting point to optimize the cracking furnaces while the CFD model study can contribute to improvements in the design of this type reactor.

Orientador: Rubens Maciel Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-11T05:06:17Z (GMT). No. of bitstreams: 1 DiazMateus_FabianAndrey_M.pdf: 2380896 bytes, checksum: be3b7c2cb01810009ddbc674d0b696e6 (MD5) Previous issue date: 2008 / Resumo: Neste trabalho é desenvolvida a modelagem matemática e a simulação computacional de um forno para processos de conversão térmica de frações pesadas de petróleo. O modelo cinético das reações de conversão é tomada de Sugaya (1993) a qual consta de uma reação irreversível de primeira ordem com 9 lumps reacionais e 24 pseudocomponentes. Os 24 pseudocomponentes são caracterizados e suas propriedades são calculadas mediante diferentes correlações e métodos encontrados na literatura. À medida que a carga avança pela tubulação do forno, a reação ocorre gerando quantidades maiores de componentes leves alterando as condições de fluxo como decorrência de alterações físico-químicas. Estes efeitos são levados em consideração na modelagem desenvolvida. O estado da mistura é verificado para cada passo de integração mediante a equação Soave Redlich Kwong. No caso de escoamento bifásico, as propriedades do líquido e do vapor são calculadas para determinar o regime de escoamento e calcular o Holdup. Este parâmetro permite estimar as propriedades de transporte, os coeficientes de transferência e a perda de carga. Inicialmente é simulada uma unidade piloto de craqueamento térmico. Esta unidade consta de uma serpentina aquecida isotermicamente, fato pelo qual só balanço de massa é integrado. O programa encontra as constantes cinéticas mediante um algoritmo Newton ¿ Raphson, cuja função objetivo é a diferença entre a conversão calculada e a conversão medida. Finalmente o forno industrial é simulado. Balanços de massa, momento, energia e temperatura de parede são integrados. Os resultados obtidos apresentam boa concordância com os dados do forno 23H ¿ 1 (Refinaria Presidente Bernardes, Cubatão) para craqueamento térmico. Deposição de coque na tubulação é avaliada para analisar o comportamento do processo. O programa desenvolvido permite o estudo do processo de craqueamento térmico para processos de conversão térmica como o coqueamento retardado e visco-redução. Novos parâmetros operacionais podem ser estudados, diferentes cargas e estratégias de controle podem ser simuladas e avaliadas com o software desenvolvido / Abstract: The mathematical modeling and the computational simulation of a process furnace for thermal conversion of heavy oil fractions is developed in this work. Kinetics of conversion reactions is from Sugaya (1993). It is based in a first order irreversible reaction with 9 lumps and 24 pseudocomponents. The 24 pseudocomponents are characterized and their properties calculated by different correlations and methods available in the literature. As walks through the furnace tubes, the feed, initially liquid, reacts generating light fractions and gas. The state of the mixture is checked for each integration step by a subroutine based on the Soave Redlich Kwong equation. When two phases are flowing, properties of the liquid and vapor are calculated to determine the flow regime and the holdup. This parameter allows to calculate the transport properties and the heat transfer and pressure drop coefficients. Initially, a thermal cracking pilot plant is simulated. This unit is formed by a reactor coil that is isothermally quenched; consequently, only mass balance is integrated. The program finds the kinetic constants by a Newton ¿ Raphson algorithm whose objective function is the difference between the calculated and measured conversion. Finally, an industrial furnace is simulated. Mass, momentum, wall temperature and energy balances are integrated. Results show good agreement whit the data reported from the industrial furnace 23-H-1 (Refinery Presidente Bernardes, Cubatão) for thermal cracking. Coke deposition in tubes is tested to analyze the performance of the process. The program developed in this work allows an insight study of thermal cracking processes such as delayed coking and visbreaking. New operational parameters, different feeds, control strategies and many other parameters can be studied. / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Orientador: Rubens Maciel Filho, Andre Jardini Munhoz / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-12T13:50:59Z (GMT). No. of bitstreams: 1 CelisAriza_OscarJavier_M.pdf: 4398609 bytes, checksum: 42adde2f8e141979345e9197e4cffadf (MD5) Previous issue date: 2008 / Resumo: Esta dissertação tem como foco estudar e propor um procedimento alternativo de craqueamento térmico de resíduos de petróleos pesados e ultra pesados por radiação laser. As principais vantagens dessa técnica estão relacionadas com a economia e a praticidade obtidas nas atividades de refino de petróleo, ao se tornar desnecessário, por exemplo, o uso de catalisadores e de grandes fornalhas nas etapas de craqueamento, reduzindo os altos custos operacionais típicos desses processos. A técnica proposta consistiu na utilização de um sistema laser de CO2 e scanner óptico de varredura. Assim, gerou-se um laser o qual foi incidido diretamente no resíduo de petróleo, fornecendo à amostra uma energia térmica suficiente para ocorrer o rompimento das cadeias dos hidrocarbonetos. Inicialmente, para se definir as condições de processo, os resíduos pesados e ultra pesados obtidos da destilação molecular tiveram suas propriedades físico-químicas (condutividade térmica (k), profundidade de absorção (d), densidade (?), peso molecular (PM) ) e térmicas (capacidade calorífica (Cp), entalpia (H) e temperatura de craqueamento (Tcrack)caracterizadas, sendo estas últimas determinadas através da técnica de calorimetria diferencial de varredura (DSC). A caracterização química dos hidrocarbonetos presentes antes e depois da irradiação foi feita num sistema de cromatografia gasosa acoplada à espectroscopia de massas (CG/EM), com uma prévia separação das frações parafínicas com o uso de coluna cromatográfica aberta. Uma condição experimental de irradiação utilizada consistiu na operação do laser de CO2 a uma potência de 25 W e a uma velocidade de varredura de 1595 mm/s sob a superfície dos resíduos ultra pesados produzindo um aumento em hidrocarbonetos característicos em C8-C10, sendo a maioria identificada como frações aromáticas (etilbenzeno, s-xileno e ?-xileno). Além disso, composto de hidrocarbonetos C25-C36 foram produzidos nos resíduos com maior peso molecular. Com as propriedades ópticas, térmicas e físico-químicas das amostras determinadas, esenvolveu-se para este processo um modelo matemático determinístico, cujas equações foram resolvidas pela técnica de elementos finitos, através do uso do software ANSYS. Os resultados de simulação juntamente com os dados experimentais permitiram identificar para a condição de irradiação estudada o comportamento térmico (transferência de calor) e as reações de craqueamento, tornando possível a estimativa da seletividade dos produtos obtidos após a incidência do laser. / Abstract: This dissertation focuses on studying and proposing an alternative procedure for the thermal cracking of heavy and ultra heavy oil residue fractions by the use of laser radiation. The main advantages to that technique include and a better operation with cost-savings, since no catalysts or big furnaces are needed, decreasing then the high costs intrinsic to the oil cracking processes. The proposed technique consisted in the use of a CO2 laser and an optical scanner system. The laser beam was focused directly on the oil residue and the supplied energy was enough to break thermally the hydrocarbon molecules. With the purpose of setting the operational conditions of the laser incidence, the heavy and ultra heavy oil residues obtained from molecular distillation had their physical-chemical (thermal conductivity (k), absorption depth (d), density (?), molecular weight (PM) ) and thermal properties (heat capacity(Cp), enthalpy (H) and cracking temperature (Tcrack) characterized, the last ones by the use of differential scanning calorimetry (DSC). The characterization of hydrocarbons founded before and after irradiation was performed in a gas chromatography-mass spectrometry system (CG/MS) with a previous n-paraffin fractions separation by an open chromatograph column. One experimental irradiation condition with a power of 25 W and scanning speed of 1595 mm/s were used on the heavy and ultra heavy oil residue surfaces. The hydrocarbon numbers in C8-C10 were increased and a large proportion of aromatic fractions (ethyl benzene, s-xylene and ?-xylene) was identified. Furthermore, hydrocarbon compounds of C25-C36 were produced in the heavy oil fractions with highest molecular weight. With the values of optical, thermal and physical-chemical properties, it was developed a deterministic mathematical model whose equations were resolved by finite element technique in ANSYS software. The results of the simulation and the experimental data led to an identification of the thermal behavior and cracking reactions under the irradiation condition. Also, the product selectivity obtained after CO2 laser incidence could be estimated. / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Beståndsdelarna som bildar betong är ballast, cement, vatten och ibland olika tillsatsmedel och tillsatsmaterial. När betongen blandas startar hydratationen som leder till att cementpastan expanderar och värme frigörs. Hydratationshastigheten avtar med tiden vilket gör att cementpastan efter en viss mognad kommer kontrahera. Dessa töjningsrörelser kan under olika omständigheter bidra till att sprickor uppstår. Sprickorna kan begränsas eller elimineras med hjälp av olika åtgärder.   Genom redogörelse för hur ingjutna kylrör minskar risken för att temperatursprickor uppstår i ung betong vid uppförandet av en simbassängkonstruktion kan syftet uppnås. Rapporten avgränsas till den första och andra fasen i betongens hårdnandeprocess.   En fallstudie har genomförts där metoden innefattar en intervju och dialog med sakkunniga, läsning i rekommenderad litteratur från företaget samt observation av arbetet innan, under och efter gjutning. Datan har verifierats för att bibehålla korrekt information.   Förekomsten av sprickor påverkas av olika faktorer som betongreceptet, mängden armering och temperatur. En konstruktions geometri med planerade gjutetapper är också betydelsefull för minimering av sprickor.   Ingjutna kylrör fördelar temperaturen i betongkroppen för att undvika att en för hög temperaturdifferens uppstår mellan betongens kärna och yta. Detta gör att betongens inre delar inte kommer expandera lika mycket och skapa ett inre tvång, på grund av värmen som hydratationen bidrar till. Värmeutvecklingen för de olika delarna har registrerats med hjälp av temperaturmätare, vilka resulterade i olika diagram.   I simbassängen uppkom inte några temperatursprickor. Dock var det svårt att urskilja om det var på grund av det specifika betongreceptet som användes eller om kylningen var den bidragande faktorn till resultatet.

Made available in DSpace on 2014-12-17T15:42:09Z (GMT). No. of bitstreams: 1 AnaCRM_TESE.pdf: 3734770 bytes, checksum: 59720290841ee6807d60b116e21f2090 (MD5) Previous issue date: 2010-12-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Microporous materials zeolite type Beta and mesoporous type MCM-41 and AlMCM-41 were synthesized hydrothermally and characterized by methods of X-ray diffraction, Fourier transform infrared, scanning electron microscopy, surface acidity, nitrogen adsorption, thermal analysis TG / DTG. Also we performed a kinetic study of sunflower oil on micro and mesoporous catalysts. The microporous material zeolite beta showed a lower crystallinity due to the existence of smaller crystals and a larger number of structural defects. As for the mesoporous materials MCM-41 and AlMCM-41 samples showed formation of hexagonal one-dimensional structure. The study of kinetic behavior of sunflower oil with zeolite beta catalysts, AlMCM-41 and MCM-41 showed a lower activation energy in front of the energy of pure sunflower oil, mainly zeolite beta. In the thermal cracking and thermocatalytic of sunflower oil were obtained two liquid fractions containing an aqueous phase and another organic - organic liquid fraction (FLO). The FLO first collected in both the thermal cracking as the thermocatalytic, showed very high level of acidity, performed characterizations of physicochemical properties of the second fraction in accordance with the specifications of the ANP. The second FLO thermocatalytic collected in cracking of sunflower oil presented results in the range of diesel oil, introducing himself as a promising alternative for use as biofuel liquid similar to diesel, either instead or mixed with it / Os materiais microporosos tipo ze?lita beta e mesoporosos tipo MCM-41 e AlMCM-41 foram sintetizados hidrotermicamente e caracterizados pelos m?todos de difra??o de raios X, infravermelho por transformada de Fourier, microscopia eletr?nica de varredura, acidez superficial, adsor??o de nitrog?nio, an?lise t?rmica via TG/DTG. Ainda foi realizado um estudo do comportamento cin?tico termogravim?trico do ?leo de girassol sobre os catalisadores micro e mesoporosos citados. Usando curvas integrais da TG e o m?todo cin?tico de Vyazovkin, foram estimados a energia de ativa??o, as taxas de convers?o e o tempo degrada??o do ?leo em fun??o da temperatura. O material microporoso ze?lita beta apresentou menor cristalinidade, devido ? exist?ncia de cristais menores e um maior n?mero de defeitos estruturais. Quanto aos materiais mesoporosos MCM-41 e AlMCM-41 apresentaram amostras com forma??o da estrutura hexagonal unidimensional. O estudo do comportamento cin?tico do ?leo de girassol com os catalisadores ze?lita beta, AlMCM-41 e MCM-41, mostrou uma menor energia de ativa??o frente a energia do ?leo de girassol puro, principalmente a ze?lita beta. No craqueamento t?rmico e termocatal?tico do ?leo de girassol foram obtidas duas fra??es l?quidas contendo uma fase aquosa e outra org?nica fra??o l?quida org?nica (FLO). A primeira FLO coletada, tanto no craqueamento t?rmico quanto no termocatal?tico, apresentou ?ndice de acidez muito elevado, sendo assim foi realizada as caracteriza??es das propriedades f?sico-qu?micas da segunda fra??o de acordo com as especifica??es da ANP. As segundas FLOs coletadas no craqueamento termocatal?tico do ?leo de girassol apresentaram resultados na faixa adequada ao diesel de petr?leo, apresentando-se como uma alternativa promissora para utiliza??o como biocombust?vel l?quido similar ao diesel, seja em substitui??o, ou misturado a este