Submitted by Caroline Xavier (caroline.xavier@pucrs.br) on 2017-06-30T13:27:41Z No. of bitstreams: 1 TES_NATALIA_FEIJO_LOPES_COMPLETO.pdf: 8285271 bytes, checksum: 119a9479b96dbe3b60816028d619c58d (MD5) / Made available in DSpace on 2017-06-30T13:27:41Z (GMT). No. of bitstreams: 1 TES_NATALIA_FEIJO_LOPES_COMPLETO.pdf: 8285271 bytes, checksum: 119a9479b96dbe3b60816028d619c58d (MD5) Previous issue date: 2017-03-24 / Conselho Nacional de Pesquisa e Desenvolvimento Cient?fico e Tecnol?gico - CNPq / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior - CAPES / Funda??o de Amparo ? Pesquisa do Estado do Rio Grande do Sul (FAPERGS) / For the oil industry, corrosion in steel is a serious problem, especially when in presence of aqueous environment and in contact with dissolved gases (CO2, H2S and O2). In cases exploration in pre-salt fields, corrosion control is even more critical, because the crude oil is extracted with high salinity and elevated CO2 content at high pressures and temperatures. Therefore, the objective of this work was to study the performance of steels used in wellbore casing (HSLA steels with 0.04% Cr and with 0.31% Cr and a superduplex steel) in a CO2 corrosive environment with a similar chemical composition to the pre-salt reservoirs, at high pressures (15 and 30 MPa) and high temperatures (50?C and 90?C). For this, batch corrosion tests, for 7 and 30 days, were performed and the assessment of the corrosion process was made through the characterization of the scales formed on the steel surface. Corrosion rates were determined by mass loss tests, the characterization of the corrosion products was made by FEG/SEM, EDS, XRD and Raman, and the properties of the corrosion products were evaluated by electrochemical measurements of potentiodynamic polarization resistance and electrochemical impedance. In addition, the in-situ corrosion process was carried out at atmospheric pressure and evaluated by means of electrochemical impedance spectroscopy (EIS) in order to compare with the results obtained at high pressures. The scales formed on the steel surface at high pressure are predominantly composed of iron carbonate enriched with calcium as substitutional element in the lattice and the results indicate that the scales that exhibited more protective properties were the ones formed at higher temperature (90?C). There was a significant improvement on the protection character of these scales with the increase of the chromium content, with special emphasis on the high performance of superduplex steel. Comparing EIS analyzes performed on pre-corroded steels with in-situ measurements, the results obtained by the measurements performed using pre-corroded samples were more coherent with the results obtained by the other evaluation methods. However, the in situ EIS measurement can be important to provide complementary information for the understanding of corrosion involving complex systems such as these studied. / Para a ind?stria petrol?fera, a corros?o em a?os ? um grave problema, principalmente quando em presen?a de meio aquoso e em contato com gases dissolvidos (CO2, H2S e O2). Em casos como no pr?-sal, o controle da corros?o ? ainda mais cr?tico, pois o petr?leo ? extra?do com ?gua de alta salinidade e elevado teor de CO2, a altas press?es e temperaturas. Desta forma, o objetivo deste trabalho foi estudar o desempenho de a?os utilizados em revestimento de po?os de petr?leo (a?os ARBL com 0,04% de Cr e com 0,31% de Cr e um a?o superduplex) frente ao ambiente corrosivo por CO2, com composi??o qu?mica similar ao pr?-sal, a altas press?es (15 e 30 MPa) e altas temperaturas (50?C e 90?C). Para isto, realizaram-se ensaios de corros?o em batelada, por 7 e 30 dias, e as an?lises do processo corrosivo foram realizadas a partir da caracteriza??o dos filmes de produto de corros?o formados na superf?cie do a?o ap?s os ensaios. As taxas de corros?o foram determinadas por perda de massa, a caracteriza??o dos produtos de corros?o foi realizada por FEG/MEV, EDS, DRX e Raman, e as propriedades eletroqu?micas dos produtos de corros?o foram avaliadas por resist?ncia de polariza??o potenciodin?mica e imped?ncia eletroqu?mica (EIS). Al?m disso, avaliou-se tamb?m o processo corrosivo in situ, por meio de espectroscopia de imped?ncia eletroqu?mica, em press?o atmosf?rica com a finalidade de comparar com os resultados obtidos a altas press?es. O produto de corros?o formado na superf?cie do a?o a alta press?o, para todas as condi??es experimentais, ? predominantemente composto por carbonato de ferro enriquecido por c?lcio substitucional e os resultados indicam que os filmes que apresentaram propriedades mais protetoras aos a?os foram os formados em temperatura mais alta (90?C). Houve uma melhora significativa no car?ter de prote??o destes filmes com o aumento do teor de cromo, com especial destaque ao elevado desempenho do a?o superduplex. Comparando as an?lises de EIS realizadas nos a?os pr?-corro?dos com as de in situ, observou-se que os resultados obtidos atrav?s das medidas realizadas nas amostras pr?-corro?das foram mais coerentes com os resultados obtidos pelos outros m?todos avaliativos. Por?m, a medida de EIS in situ pode ser importante para fornecer informa??es complementares para a compreens?o da corros?o envolvendo sistemas complexos como estes estudados.

Submitted by Celso Magalhaes (celsomagalhaes@ufrrj.br) on 2017-07-17T15:09:58Z No. of bitstreams: 1 2016 - L?gia Marcondes Rodrigues dos Santos.pdf: 1928089 bytes, checksum: 74cdeac055ec3629545f632b08dd75c4 (MD5) / Made available in DSpace on 2017-07-17T15:09:58Z (GMT). No. of bitstreams: 1 2016 - L?gia Marcondes Rodrigues dos Santos.pdf: 1928089 bytes, checksum: 74cdeac055ec3629545f632b08dd75c4 (MD5) Previous issue date: 2016-11-28 / Beer is the most consumed beverage in the world and Brazil is the third biggest producer just behind USA and China. It is an alcoholic beverage made from malted cereals, water, hops and yeast. To produce beer, water and malt are mixed and heated, what it is called the mashing step which aims to promote gelatinization and the starch hydrolyzation by the enzymes of the malt: ? and ? amylases. Since by using high hydrostatic pressure (HHP) it is possible to realize both processes (gelatinization and hydrolysis), mashing can use this technology without the need of heating and to raise productivity of the brewhouse. The aim of this study was to evaluate the use of HHP on starch hydrolysis and the sugar profile formed. For this, worts (water and malt solution ? ratio 4:1) were treated with HHP in 300, 400 or 500 MPa for 5, 10 and 15 minutes, and as control sample, the same solution was treated with heat (1st step: 52?C / 20 min; 2nd step: 72 ?C / 25 min; 3rd step: 78 ?C / 5 min). After, it was made the sugar profile by high performance liquid chromatography (HPLC), soluble solids content by density and microscopic analysis of gelatinized starch. As results, it was possible to verify a decrease on starch concentration (indication of hydrolysis) and a progressive swelling (indication of gelatinization) of the granules, especially at 500 MPa. The iodine test, which assesses starch presence, showed the same results of microscopy analysis and, on both qualitative assessments, the pressure level was of great influence and only on the iodine test, time seems to have had any influence since it was observed a decrease on starch content as time increased at 500 MPa. The sugar profile revealed five main sugars in all worts: glucose, sucrose, fructose, maltose and maltotriose. The maltose, maltotriose and fructose?s contents of the pressurized worts were similar to the heat treatment (500 MPa / 5 ? 15 min). Fructose and glucose exhibited and increase in most of the pressurizations. Sucrose and soluble solids contents of the pressurized samples were lower than the heated one. Among the pressure levels studied, there was a trend of increase on soluble solids, maltose, maltotriose and glucose?s content as the pressure was raised and generally, pressure influenced all sugar?s contents, except from sucrose. Time had a small effect on sugar?s content in some pressure levels. The variations observed to maltose, maltotriose and soluble solids were adjusted to mathematical models of fourth grade that exhibited a strong influence of pressure without dependence of the time effect. Additionally, the principal component analysis explained the variance with formation of three main clusters: heated wort, 500 MPa / 10 or 15 min wort and the other pressurized worts. The results showed that high hydrostatic pressure was able to promote desirable changes on mashing concerning gelatinization and hydrolysis with formation of desirable sugars, especially at 500 MPa. It suggests that it?s possible to produce wort by HHP providing productivity gains, once HHP takes less time (5 min against 80 min of usual heat process) and less energy consumption. / A cerveja ? a bebida alco?lica mais consumida no mundo, e o Brasil ? o terceiro maior produtor. No processo de produ??o convencional, a mostura ? a etapa que objetiva prioritariamente, promover gelatiniza??o e hidr?lise enzim?tica do amido pelas enzimas end?genas ? e ? amilases. A alta press?o hidrost?tica (APH) ? capaz de promover a gelatiniza??o de amido e ativa??o de enzimas e, desta maneira, a mostura demonstra ser uma etapa da fabrica??o de cerveja capaz de utilizar APH, no entanto h? poucos estudos na literatura sobre esta aplica??o. A adequa??o dessa tecnologia poder? propiciar esta etapa do processo sem necessidade de calor e com tempo reduzido, o que reverter? em aumento de produtividade e capacidade da ind?stria cervejeira. Desta maneira, o objetivo deste trabalho foi avaliar o efeito do processo da APH sobre a hidr?lise do amido para forma??o de a??cares durante a mostura. Para isso, mostos (solu??o contendo ?gua e malte ? 4:1) foram tratados por alta press?o hidrost?tica (APH) a 300, 400 ou 500 MPa por 5, 10 ou 15 minutos e, como controle do experimento, a mesma solu??o foi tratada termicamente (TT: 1? fase: 52?C / 20 min; 2? fase: 72 ?C / 25 min; 3? fase: 78 ?C / 5 min) . Posteriormente, procedeu-se an?lise do perfil de a??cares por cromatografia l?quida de alta efici?ncia (HPLC), o teor de s?lidos sol?veis por densitometria e an?lise microsc?pica da gelatiniza??o do amido. Como resultado, observou-se atrav?s da microscopia que houve diminui??o na concentra??o de amido (indicativo de hidr?lise) e um progressivo inchamento (indicativo de gelatiniza??o) dos gr?nulos com o aumento da press?o, principalmente a 500 MPa. O resultado do teste iodo (que avalia presen?a de amido) corroborou com o resultado da microscopia, indicando a diminui??o na concentra??o de amido a 500 MPa. O perfil de a??car revelou cinco sacar?deos principais: sacarose, frutose, glicose, maltose e maltotriose. As concentra??es de maltose, maltotriose e frutose dos mostos pressurizados foram similares ?s observadas no mosto TT quando nos n?veis mais intensos (500 MPa / 5, 10 e 15 min). Frutose e glicose exibiram aumento de concentra??o na maioria dos tratamentos avaliados. O teor de sacarose e de s?lidos sol?veis foram inferiores ao observado no mosto TT em todos os mostos tratados por APH. Entre os n?veis de APH avaliados, observou-se tend?ncia de aumento da concentra??o de s?lidos sol?veis, maltose, maltotriose e glicose com o aumento da intensidade de APH. De maneira geral, o efeito da press?o alterou o teor de todos os a??cares, exceto sacarose. J? o tempo exerceu discreto efeito na concentra??o dos a??cares quando pressurizados em alguns n?veis de press?o. O modelo matem?tico que melhor se ajustou aos dados experimentais dos teores de maltose, maltotriose e s?lidos sol?veis foi o de quarto grau, que exibiu forte influ?ncia do fator press?o sem depend?ncia do fator tempo, corroborando com as outras an?lises deste estudo. Adicionalmente, an?lises de componentes principais exibiu explica??o (CP1 + CP2) a 92 % de vari?ncia com forma??o de tr?s clusters principais: mosto TT, mostos 500 MPa / 10 ou 15 min e demais mostos tratados por APH. Os resultados demostraram que a APH foi capaz de promover as altera??es desej?veis no processo de mostura no que se refere aos efeitos de gelatiniza??o e hidr?lise com forma??o dos a??cares de interesse, principalmente nos n?veis mais intensos (500 MPa) de press?o. Esse resultado sugere que a produ??o de mosto por APH ? vi?vel tecnicamente, podendo vir a proporcionar ganho expressivo de produtividade, uma vez que a APH demanda menos tempo (5 min contra 80 min do tratamento t?rmico) e h? redu??o do consumo de energia.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-08-29T17:58:31Z No. of bitstreams: 1 2017 - Fabiola dos Santos Gouvea.pdf: 2182163 bytes, checksum: dfda9ecfc3001fc4f7db7aa0e3138b6a (MD5) / Made available in DSpace on 2017-08-29T17:58:31Z (GMT). No. of bitstreams: 1 2017 - Fabiola dos Santos Gouvea.pdf: 2182163 bytes, checksum: dfda9ecfc3001fc4f7db7aa0e3138b6a (MD5) Previous issue date: 2017-02-20 / CAPES / Consumers are increasingly becoming more critical in the selection of a food product, by mainly considering sensory, nutritional and safety issues in the decision to purchase. As a result, less drastic preservation methods have been more deeply investigated and broadly adopted in industrial scale, including the addition of natural antimicrobials and the high hydrostatic pressure processing. In this sense, the objective of the this study was to evaluate the effect of the incorporation of carrot either individually or in combination with high pressure tretament on the inhibition of Listeria innocua inoculated in Minas Frescal cheese, besides evaluating the effect on the proximate composition, carotenoids content and sensorial characteristics and acceptance. A 22 factorial design was first employed to perform the chemical and physical characterization, being the independent variables the pressure (0 and 500 MPa) and the carrot concentration (0% and 6%), with three repetitions of the central point. The following analyses were carried out in the cheeses resulting from the treatments: proximate composition (moisture, protein, ethereal extract, fixed mineral residue - FMR); instrumental color; carotenoid quantification (total carotenoids, lutein, ?-carotene and ?-carotene) and enumeration of Listeria innocua. For the sensory analysis, a full factorial design was adopted, by considering the central points of the first design as factors themselves. The global acceptance was evaluated by a 9-point hedonic scale and the CATA Test (check-all-that-apply) with 102 consumers. High pressure processing at the level of 500 MPa for 10 minutes reduced the Listeria innocua count from 7 log cfu /ml up to undetectable levels, without further sigificant increase along the chilled storage at 8 ?C for 22 days. On the contrary, the single carrot incorporation (6%) or its combination in the level of (3%) with pressure treatment at (250 MPa) had no effect on the inhibition of this microorganism. Moisture content, protein, ethereal extract and FMR were not significantly affected by either the carrot incorporation or the high pressure processing. As expected, carrot addition enhanced the levels of total carotenoids, lutein, ?-carotene and ?-carotene, as well as affected the instrumental color parameters. There again, high pressure processing had no significant effect on these compounds. Furthermore, high hydrostatic pressure processing did not influence the overall acceptance of the samples, while the incorporation of 6% of carrot tended to lower the acceptance. In the analyzis of individual consumers, the cheese with 3% of carrot processed at 250 MPa did not differ from the control sample, which was the most preferred sample. According to the CATA test, the consumers were able to sensory characterize and differentiate between the cheeses with or without the addition of carrot. / Os consumidores t?m se tornado mais cr?ticos na escolha de um produto aliment?cio, sendo as caracter?sticas sensoriais, nutricionais e funcionais, assim como a seguran?a do alimento, fatores preponderantes na decis?o de compra do consumidor. Tais demandas t?m induzido a busca por m?todos alternativos de conserva??o, menos danosos ? qualidade do produto, como adi??o de antimicrobianos naturais e o processamento por alta press?o hidrost?tica. Nesse sentido, o presente estudo objetivou avaliar o efeito da incorpora??o da cenoura e do tratamento por alta press?o hidrost?tica na inibi??o da Listeria innocua e nas caracter?sticas qu?micas, f?sica, microbiol?gicas e sensoriais do queijo Minas Frescal, visando desenvolver um produto diferenciado, mais seguro e saud?vel. O processamento dos queijos seguiu um delineamento fatorial 22 com os fatores: press?o (0 e 500 MPa) e concentra??o de cenoura (0 e 6%) com 3 repeti??es do ponto central. Foram realizadas an?lises f?sico-quimicas (umidade, prote?na, extrato et?reo, res?duo mineral fixo (RMF) e cor instrumental), quantifica??o dos carotenoides (carotenoides totais, lute?na, ?-caroteno e ?-caroteno) e contagem de Listeria innocua. A an?lise sensorial seguiu um delineamento fatorial completo (considerando os pontos centrais como fatores), em que foi avaliado a aceita??o global pela escala hed?nica de 9 pontos e o Teste CATA (check-all-that-apply) com 102 consumidores. O processamento por alta press?o em 500 MPa por 10 minutos reduziu a contagem de Listeria innocua em aproximadamente 7 log ufc/mL, para n?veis n?o detect?veis imediatamente ap?s o processamento, e essa contagem se manteve constante ao longo do armazenamento a 8?C por 22 dias. J? a incorpora??o individual (sem pressuriza??o) da cenoura (6%), ou a utiliza??o combinada desta na concentra??o de 3% com a press?o de 250 MPa, n?o apresentou efeito na inibi??o desse micro-organismo. Os teores de umidade, prote?na, extrato et?reo e RMF tamb?m n?o foram afetados significativamente pela incorpora??o da cenoura ou pelo processamento de alta press?o hidrost?tica. Como esperado, a incorpora??o da cenoura aumentou os teores de carotenoides totais, lute?na, ?-caroteno e ?-caroteno, bem como influenciou nos par?metros de cor instrumental. Em contrapartida, o processamento por alta press?o n?o apresentou efeito significativo sobre esses compostos. O processamento por alta press?o hidrost?tica pouco influenciou na aceita??o global da amostras, enquanto que a incorpora??o de 6% de cenoura tendeu a uma menor aceita??o. Quando analisados os consumidores individualmente, foi verificado que a amostra processada a 250 MPa com 3% de cenoura n?o diferiu da amostra controle, sendo essas as mais preferidas. O teste CATA mostrou que os consumidores conseguiram diferenciar e caracterizar sensorialmente os queijos incorporados com cenoura dos n?o adicionados.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-10-11T21:36:55Z No. of bitstreams: 1 DivalDeBritoGuerraNeto_TESE.pdf: 2280333 bytes, checksum: 547f847c8d3a073e28a74856b347d0d5 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-10-14T22:36:16Z (GMT) No. of bitstreams: 1 DivalDeBritoGuerraNeto_TESE.pdf: 2280333 bytes, checksum: 547f847c8d3a073e28a74856b347d0d5 (MD5) / Made available in DSpace on 2016-10-14T22:36:17Z (GMT). No. of bitstreams: 1 DivalDeBritoGuerraNeto_TESE.pdf: 2280333 bytes, checksum: 547f847c8d3a073e28a74856b347d0d5 (MD5) Previous issue date: 2016-02-19 / O petr?leo ? uma mistura complexa, havendo predomin?ncia de hidrocarbonetos paraf?nicos, naft?nicos e arom?ticos (Freitas e Costa, 1969) al?m de outros constituintes (sulfurados, nitrogenados e oxigenados) que ocorrem normalmente na forma de compostos org?nicos. O CO2, por exemplo, estar presente em mais de 25% do ?leo extra?do da camada do pr?-sal entre as bacias de Campos e Santos. Estimativas apontam que somente nas duas ?reas com reservas delimitadas - os campos de Tupi e Iara, onde h? um ac?mulo de at? 12 bilh?es de barris de ?leo e g?s - existam 3,1 bilh?es de toneladas de CO2, um dos gases que contribuem para o aquecimento do planeta. Devido a essa grande quantidade de contaminantes (CO2, N, S, etc.) presente na mistura de hidrocarbonetos extra?da dessas bacias, ? preciso buscar novas pr?ticas de separa??o deste contaminante. Para tal desenvolvimento de novas pr?ticas ? importante um estudo constante sobre o equil?brio termodin?mico entre os constituintes do petr?leo e seus contaminantes. Com isso o objetivo ? construir um equipamento que gere condi??es suficientes para poder verificar o comportamento de fase de v?rios sistemas de interesse da ind?stria do petr?leo com seus contaminantes mais comuns, por exemplo: CO2 a alta press?o utilizando o conhecimento pr?vio do grupo Neto, 2010 de pesquisa, que deve operar em press?es e temperaturas de at? 300 bar e temperatura at? 100 graus Celsius. Alguns sistemas de interesse s?o: CO2 e alcanoaminas (monoetanolamina, dietanolamina, trietanolamina). ?gua e ?lcool laur?lico etoxilado e CO2 e alcanos com leve contamina??o de ?gua. / Oil is a complex mixture having predominantly paraffinic hydrocarbons, naphthenic and aromatic (Freitas and Costa, 1969) and other constituents (sulfur, nitrogen and oxygen) that normally occur in the form of organic compounds. The CO2, for example, be present in over 25% of the oil extracted from the pre-salt layer of the Campos and Santos basins. Estimates suggest that only in two areas with defined reserves - the Tupi and Iara, where there is an accumulation of up to 12 billion barrels of oil and gas - there are 3.1 billion tons of CO2, one of the gases that contribute to warming. Because of this large amount of contaminants (CO2, N, S, etc.) present in the mixture of hydrocarbons extracted these basins, it must find new ways of separation of this contaminant. For such development of new practices is important a constant study of the thermodynamic equilibrium between oil constituents and their contaminants. Thus the goal is to build a device that generates enough conditions to check phase behavior of various oil industry's interest systems with their most common contaminants, eg CO2 at high pressure using prior knowledge of Guerra-Neto, 2010, which must operate at temperatures and pressures up to 300 bar and temperatures up to 100 degrees Celsius. Some systems of interest are: CO2 and alcanoaminas (monoetanolamine, dietanolamine, trietanolamine). Lauryl alcohol ethoxylate and water and CO2 and alkanes with mild contamination of water.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-05T22:23:13Z No. of bitstreams: 1 LeonardoResende_DISSERT.pdf: 7377959 bytes, checksum: 16ea1cdbf54927d2b45fc0aac9163621 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-02-16T00:06:40Z (GMT) No. of bitstreams: 1 LeonardoResende_DISSERT.pdf: 7377959 bytes, checksum: 16ea1cdbf54927d2b45fc0aac9163621 (MD5) / Made available in DSpace on 2016-02-16T00:06:40Z (GMT). No. of bitstreams: 1 LeonardoResende_DISSERT.pdf: 7377959 bytes, checksum: 16ea1cdbf54927d2b45fc0aac9163621 (MD5) Previous issue date: 2014-09-24 / Do ponto de vista econ?mico, a metalurgia do p? (MP) ? uma t?cnica bastante usada para a produ??o de pe?as de pequeno porte. ? poss?vel, atrav?s da MP e de uma pr?via cominui??o de res?duos s?lidos tais como cavacos ferrosos, produzir pe?as sinterizadas altamente densas e de interesse para a ind?stria automotiva, eletr?nica e aeroespacial. No entanto, sem essa pr?via cominui??o dos cavacos, a produ??o de corpos com densidade igual a densidade te?rica por t?cnicas convencionais de sinteriza??o necessitaria do uso de aditivos ou de temperaturas significativamente maiores do que 1250?C. Uma rota alternativa para a fabrica??o de corpos sinterizados com alta densidade a partir de compacta??o de cavacos ferrosos (? 850 ?m) e sinteriza??o em fase s?lida ? a t?cnica de compacta??o sob alta press?o (AP). Nesse trabalho, foram usadas diferentes press?es de compacta??o para a produ??o de sinterizados de cavacos de a?o carbono SAE 1050. Especificamente, foi investigado o efeito da alta press?o de compacta??o no comportamento da densifica??o das amostras sinterizadas. Portanto, amostras de cavacos do a?o carbono SAE 1050 foram compactadas uniaxialmente a frio sob press?es de 500 e 2000 MPa, respectivamente. Os corpos verdes obtidos foram sinterizados sob atmosfera carbonetante a 1100 e 1200?C por 90 minutos. A taxa de aquecimento usada foi de 20?C/min. Os materiais de partida e os corpos sinterizados foram caracterizados por microscopia ?ptica, MEV, DRX, medidas de densidade (geom?trica: massa/volume, e picnometria) e medidas de microdureza Vickers e dureza Rockwel. Os resultados obtidos mostraram que os compactos produzidos sob 2000 MPa apresentaram valores de densidade relativa de 93% a 100% da densidade te?rica e microdureza entre 150 HV e 180 HV, respectivamente. Diferentemente, os compactados sob 500 MPa apresentaram uma microestrutura bastante heterog?nea, valor de densidade abaixo de 80% da densidade te?rica e condi??es estruturais das amostras inadequadas para a realiza??o das medidas de microdureza e dureza. Os resultados obtidos indicam que utiliza??o da compacta??o sob alta press?o de cavacos ferrosos ? uma rota bastante promissora para melhorar as condi??es de sinterabilidade deste tipo de material, pois, al?m de promover uma maior compacta??o do material de partida, a tens?o externa atua, juntamente com a tens?o superficial, funcionando como for?a motriz para o processo de sinteriza??o. Adicionalmente, press?es extremamente elevadas permitem a deforma??o pl?stica dos materiais, promovendo um contato ?ntimo e extenso das part?culas e eliminando poros e trincas. Isso tende a diminuir o tempo e/ou a temperatura necess?rias para uma boa sinteriza??o, evitando-se o crescimento excessivo de gr?os, sem o uso de aditivos. Al?m disso, as press?es elevadas provocam fratura nos gr?os em materiais fr?geis ou d?cteis altamente encruados, o que propicia um p? de partida, para a sinteriza??o, mais fino, sem os riscos de contamina??o presentes quando s?o usados m?todos de cominui??o pr?via do p?. / From an economic standpoint, the powder metallurgy (P/M) is a technique widely used for the production of small parts. It is possible, through the P/M and prior comminution of solid waste such as ferrous chips, produce highly dense sintered parts and of interest to the automotive, electronics and aerospace industries. However, without prior comminution the chip, the production of bodies with a density equal to theoretical density by conventional sintering techniques require the use of additives or significantly higher temperatures than 1250?C. An alternative route to the production of sintered bodies with high density compaction from ferrous chips (? 850 microns) and solid phase sintering is a compression technique under high pressure (HP). In this work, different compaction pressures to produce a sintered chip of SAE 1050 carbon steel were used. Specifically, the objective was to investigate them, the effect of high pressure compression in the behavior of densification of the sintered samples. Therefore, samples of the chips from the SAE 1050 carbon steel were uniaxially cold compacted at 500 and 2000 MPa, respectively. The green compacts obtained were sintered under carbon atmosphere at 1100 and 1200?C for 90 minutes. The heating rate used was 20?C/min. The starting materials and the sintered bodies were characterized by optical microscopy, SEM, XRD, density measurements (geometric: mass/volume, and pycnometry) and microhardness measurements Vickers and Rockwell hardness. The results showed that the compact produced under 2000 MPa presented relative density values between 93% and 100% of theoretical density and microhardness between 150 HV and 180 HV, respectively. In contrast, compressed under 500 MPa showed a very heterogeneous microstructure, density value below 80% of theoretical density and structural conditions of inadequate specimens for carrying out the hardness and microhardness measurements. The results indicate that use of the high pressure of ferrous chips compression is a promising route to improve the sinterability conditions of this type of material, because in addition to promoting greater compression of the starting material, the external tension acts together with surface tension, functioning as the motive power for sintering process. Additionally, extremely high pressures allow plastic deformation of the material, providing an intimate and extended contact of the particles and eliminating cracks and pores. This tends to reduce the time and / or temperature required for good sintering, avoiding excessive grain growth without the use of additives. Moreover, higher pressures lead to fracture the grains in fragile or ductile materials highly hardened, which provides a starting powder for sintering, thinner, without the risk of contamination present when previous methods are used comminution of the powder.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-08-10T11:24:30Z No. of bitstreams: 1 MeysamMashhadikarimi_TESE.pdf: 7466845 bytes, checksum: 3ec1fdf5f0b341e5aa20ba33dd8d5104 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-08-10T14:09:43Z (GMT) No. of bitstreams: 1 MeysamMashhadikarimi_TESE.pdf: 7466845 bytes, checksum: 3ec1fdf5f0b341e5aa20ba33dd8d5104 (MD5) / Made available in DSpace on 2017-08-10T14:09:43Z (GMT). No. of bitstreams: 1 MeysamMashhadikarimi_TESE.pdf: 7466845 bytes, checksum: 3ec1fdf5f0b341e5aa20ba33dd8d5104 (MD5) Previous issue date: 2017-07-10 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Neste trabalho de pesquisa, foi obtido um compacto de diamante policristalino (PDC), constitu?do de uma camada superior de diamante policristalino sob um substrato de WC-10% em peso de Co e uma interface de WC-20% em peso de Nb/Ni entre as camadas, atrav?s de m?todo de sinteriza??o de alta press?o e alta temperatura (HPHT). Para alcan?ar esse objetivo, foram realizadas tr?s etapas distintas. Na primeira etapa, foi sinterizado o corpo de diamante com um ligante adequado, e foram obtidos os melhores par?metros de sinteriza??o. Na segunda etapa, foi realizado o estudo de diferentes condi??es de sinteriza??o para o substrato de metal duro WC-10% p.Co. E, na terceira e ?ltima etapa, foi produzido, de acordo com os resultados alcan?ados nas etapas anteriores, o compacto de diamante policristalino de camada tripla (PDC). Na primeira etapa, quatro ligantes diferentes foram usados para sinterizar o diamante atrav?s do m?todo HPHT. Os ligantes utilizados foram o Nb/Fe, Nb/Co, Nb/Ni e Nb puro, sendo 10% em peso de ligante utilizado para cada composi??o. A sinteriza??o foi realizada a diferentes temperaturas e sob diferentes press?es e tempos. As amostras obtidas foram analisadas atrav?s das medidas de densidade relativa e dureza, al?m das imagens eletr?nicas de varredura, para encontrar os melhores par?metros de sinteriza??o e ligante. Os estudos mostraram que o Nb apresentou o melhor comportamento, e que os melhores par?metros de sinteriza??o foram: T = 1750 ?C, P = 7,7 GPa, t = 6 minutos. Na segunda etapa, uma mistura em p? de WC-10% em peso de Co foi sinterizado atrav?s de HPHT sob press?o de 7,7 GPa, variando temperatura (1500 ?C, 1600 ?C, 1700 ?C, 1800 ?C, 1900 ?C) e tempo (2 e 3 minutos). As an?lises microestruturais e estruturais foram realizadas atrav?s de MEV/EDS e DRX. Ensaios de dureza, tenacidade (ITF) e de resist?ncia ? compress?o, tamb?m, foram realizados para entender os efeitos de diferentes par?metros de sinteriza??o nas propriedades dos sinterizados, verificando-se densifica??o total das amostras sinterizadas a altas temperaturas. Entretanto, foi observado um crescimento anormal de gr?os para estas mesmas temperaturas. Altos valores de dureza foram observados, aproximadamente, entre 1250 a 1650 HV para todas as amostras sinterizadas. Na terceira etapa, para a obten??o do PDC, uma camada fina de WC-20% em peso de Nb/Ni foi utilizada para a forma??o da interface entre a camada superior de diamante com ligante de Nb pura e o substrato de WC 10% em peso de Co. A sinteriza??o foi feita atrav?s do m?todo HPHT ? temperatura de 1750 ?C sob 7,7 GPa de press?o. Foram utilizados dois tempos diferentes, de 6 min. (tr?s sucessivos 2 minutos) e 9 min. (tr?s sucessivos 3 minutos). A dureza foi medida e os estudos estruturais/microestruturais foram realizados atrav?s de an?lises de MEV/EDS. Em suma, os resultados mostraram que este novo tipo de PDC pode ser produzido com sucesso, usando um novo ligante, o niobio puro, para o diamante, sem qualquer presen?a de grafitiza??o. Verificou-se tamb?m que o uso de uma interface com os mesmos elementos constituintes do substrato e do corpo de diamante sinterizado resultou numa boa ades?o entre as camadas, o que pode resultar em melhor desempenho e melhorar a durabilidade do PDC. / The primary objective of this thesis was to obtain a triple layer polycrystalline diamond compact (PDC) containing a polycrystalline diamond as top layer, a WC 10 wt% Co substrate, and a WC 20 wt% Nb/Ni interface to bond these two layers via high pressure high temperature (HPHT) sintering. To achieve this objective, the project has been done in three different stages. The first stage was producing diamond sintered body with a suitable binder, and finding the best sintering parameters. The second stage of project was done to study the WC 10 wt% Co hardmetal substrate at different sintering conditions, and the third and last stage was done according to the results achieved from previous stages to obtain a triple layer PDC. At the first stage, four different binders were used to sinter diamond under HPHT condition. Binders were Nb/Fe, Nb/Co, Nb/Ni and pure Nb and 10 wt% binder was used. Sintering was carried out at different temperature and under different pressure and holding time. Obtained samples were studies according to relative density, microstructure, and hardness to find the optimum binder and sintering parameters. Studies at this stage showed that Nb is the best binder and T=1750 ?C, 7.7 GPa with holding time more than 6 minutes are the best sintering parameters. At the second stage a powder mixture of WC 10 wt% Co was sintered via HPHT at 1500, 1600, 1700, 1800, and 1900?C under 7.7 GPa pressure for 2 and 3 minutes. Microstructural/structural analyses were performed by SEM/EDS and XRD and hardness, Indentation Fracture Toughness (ITF) and compression tests were also carried out to understand effects of different sintering parameters. At this stage, it was found that full density can achieved for high sintering temperature along with abnormal grain growth. High hardness was observed in range starting from 1250 up to 1650 HV. At the third stage, to obtain PDC, a thin layer of WC 20 wt% Nb/Ni was used as an interface between top layer of diamond with pure Nb binder and WC 10 wt% Co substrate. Sintering was done via HPHT method at 1750?C under 7.7 GPa of pressure. Two different holding time of 6 (three successive 2 minutes) and 9 (three successive 3 minutes) were used. Hardness was measured and microstructural/structural studies were done via SEM/EDS. The overall results showed that this new kind of PDC can successfully produce using a new pure Niobium binder for diamond without any graphitization. It was also found that using an interface having the resemblance to both substrate and sintered diamond body caused good adhesion between layers that can results in enhanced performance and improving durability of PDC.

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2018-10-19T17:51:25Z No. of bitstreams: 1 2013 - Ellen Almeida dos Santos Ferreira.pdf: 1317610 bytes, checksum: dd687bdd4e12dc0f868a15a961aa31ed (MD5) / Made available in DSpace on 2018-10-19T17:51:25Z (GMT). No. of bitstreams: 1 2013 - Ellen Almeida dos Santos Ferreira.pdf: 1317610 bytes, checksum: dd687bdd4e12dc0f868a15a961aa31ed (MD5) Previous issue date: 2013-05-06 / Brazil is a big producer and exporter of fruits and fruit juice. The sale, in many cases, is limited to the seasonality of production and perishability of fruits. The Brazilian cherry is a tropical fruit originally from the South and Southeast regions of Brazil, with high perishability and susceptibility to physical damage during transport. Considering all the losses that the productive chain of fresh Brazilian cherry may suffer, it is evident the importance of producing the juice of this fruit. Traditionally, thermal treatment has been employed in the processing and preservation of these products; however, undesirable changes in sensory and nutritional characteristics can happen. Among the innovative technologies to reduce these undesirable changes is High Hydrostatic Pressure (APH). This method of food preservation provides additional benefits to the product allowing products closer to the fresh product. This study aimed to investigate the process of high pressure in the preservation of Brazilian cherry pulp (Eugenia uniflora L.) to assess their microbiological safety and sensory quality and nutritional nectar obtained. The study was conducted at Embrapa Food Technology (Rio de Janeiro-RJ, Brazil). The Brazilian cherry pulp was processed by high hydrostatic pressure using different pressure levels, temperatures and retention time, following a central composite design. Microbiological analyzes were performed (for Salmonella spp., Coliforms at 45? C, mesophilic aerobic, yeasts and molds), physico-chemical (pH, acidity, soluble solids, fibers), antioxidant activity and instrumental color. It was investigated nectar microbiological shelf life obtained from the pressurized pulp. Shelf life estimation through Survival Analysis was also carried out, and the nectar exceeded 35 days of storage. Further studies are recommended. The sensory characteristics of nectars obtained from the pressurized pulp, non-pressurized pulp (Control), pasteurized Control, and three commercial brands available in the market were evaluated by consumer acceptance and through the methodology check all that apply (CATA). Data were analyzed using analysis of variance, Tukey test, and Multiple Factor Analysis. The high pressure process has been effective in preserving the nectar refrigerated for up to 35 days. There was no significant negative effect on antioxidant activity and color of the samples subjected to high pressure. The results obtained in the determination of "ideal" pulp concentration and sweetness for the nectar formulation cherry were 36% and 10%, respectively. In Acceptance Test samples pressurized and commercial B had the highest scores and the terms most frequently used in the methodology check all that apply were reddish, cherry flavor, presence of particles, attractive color, acid, astringent, off-flavor, sweet, bitter, gritty look. Such terms are therefore considered the most suitable to describe the samples by consumers. / O Brasil ? um grande produtor e exportador de frutas e suco de frutas. A comercializa??o, em muitos casos, ? limitada ? sazonalidade da produ??o e ? perecibilidade das frutas. A pitanga ? uma fruta tropical origin?ria das regi?es Sul e Sudeste do Brasil, com alta perecibilidade e susceptibilidade a danos f?sicos durante o transporte. Tendo em vista todas as perdas que a cadeia produtiva da pitanga in natura pode sofrer, fica evidente a relev?ncia da obten??o do suco deste fruto. Tradicionalmente o tratamento t?rmico tem sido empregado no processamento e conserva??o destes produtos; no entanto, altera??es indesej?veis nas caracter?sticas nutricionais e sensoriais podem acontecer. Entre as tecnologias inovadoras para redu??o dessas altera??es indesej?veis, est? a Alta Press?o Hidrost?tica (APH). Este m?todo de conserva??o de alimentos oferece benef?cios adicionais ao produto permitindo a obten??o com caracter?sticas mais pr?ximas do produto in natura. Este estudo teve como objetivo investigar o processo de alta press?o na conserva??o de polpa de pitanga (Eugenia uniflora L.) de modo a avaliar a seguran?a microbiol?gica e a qualidade sensorial e nutricional do n?ctar obtido. O trabalho foi realizado na Embrapa Agroind?stria de Alimentos (Rio de Janeiro, RJ, Brasil). A polpa de pitanga foi processada por alta press?o hidrost?tica utilizando diferentes n?veis de press?o e tempo de reten??o, seguindo delineamento experimental do tipo composto central. Foram realizadas an?lises microbiol?gicas (para Salmonella spp., coliformes ? 45?C, aer?bios mes?filos e fungos filamentosos e leveduras), f?sico-qu?micas (pH, acidez, s?lidos sol?veis, fibras), atividade antioxidante, cor instrumental e avalia??o sensorial. Foi avaliada a vida ?til microbiol?gica do n?ctar obtido a partir da polpa pressurizada e sensorialmente atrav?s da an?lise de sobreviv?ncia (Survival Analysis). O n?ctar apresentou vida ?til superior a 35 dias, necessitando estudos subsequentes. As caracter?sticas sensoriais dos n?ctares obtidos a partir da polpa pressurizada, da polpa n?o pressurizada (controle), do controle pasteurizado e de tr?s marcas comerciais dispon?veis no mercado foram avaliadas atrav?s da aceita??o do consumidor e utilizando a metodologia check all that apply (CATA). Os dados foram analisados por An?lise de Vari?ncia, teste de m?dia, e An?lise M?ltipla de Fatores. O processamento da polpa por alta press?o foi eficaz na preserva??o do n?ctar refrigerado por at? 35 dias. N?o houve efeito negativo da APH na atividade antioxidante das amostras. Nas an?lises de cor todos os par?metros analisados (L*, a* e b*) diferiram (p<0,05) do controle (polpa n?o pressurizada) e as amostras pressurizadas. Os resultados obtidos na determina??o de concentra??o de polpa e do?ura ?ideais? para a formula??o do n?ctar de pitanga foram 36% e 10%, respectivamente. No Teste de Aceita??o as amostras pressurizada e comercial B obtiveram as maiores m?dias e na metodologia check all that apply, os termos utilizados mais frequentemente como descritores foram cor avermelhada, sabor de pitanga, presen?a de part?culas, cor atrativa, ?cido, adstringente, sabor estranho, gosto doce, gosto amargo, aspecto arenoso. Tais termos podem ser, portanto, considerados os mais apropriados na descri??o das amostras pelos consumidores.

Made available in DSpace on 2014-12-17T15:01:24Z (GMT). No. of bitstreams: 1 DivalBGN_DISSERT.pdf: 2637921 bytes, checksum: 83fbea74e9888e52417cea5286defdaa (MD5) Previous issue date: 2010-12-22 / Crude oil is a complex liquid mixture of organic and inorganic compounds that are dominated by hydrocarbons. It is a mixture of alkanes from the simplest to more complex aromatic compounds that are present derivatives such as gasoline, diesel, alcohol, kerosene, naphtha, etc.. These derivatives are extracted from any oil, however, only with a very high quality, in other words, when the content of hydrocarbons of low molecular weight is high means that production of these compounds is feasible. The American Petroleum Institute (API) developed a classification system for the various types of oil. In Brazil, the quality of most of the oil taken from wells is very low, so it is necessary to generate new technology to develop best practices for refining in order to produce petroleum products of higher commercial value. Therefore, it is necessary to study the thermodynamic equilibrium properties of its derivative compounds of interest. This dissertation aims to determine vapor-liquid equilibrium (VLE) data for the systems Phenilcyclohexane - CO2, and Cyclohexane - Phenilcyclohexane - CO2 at high pressure and temperatures between 30 to 70oC. Furthermore, comparisons between measured VLE experimental data from this work and from the literature in relation to the Peng- Robinson molecular thermodynamic model, using a simulation program SPECS IVCSEP v5.60 and two adjustable interaction parameters, have been performed for modeling and simulation purposes. Finally, the developed apparatus for determination of phase equilibrium data at high pressures is presented / O petr?leo bruto ? uma complexa mistura l?quida de compostos org?nicos e inorg?nicos em que predominam os hidrocarbonetos, desde os alcanos mais simples at? os arom?ticos mais complexos. Nessa mistura encontram-se presentes derivados como gasolina, diesel, ?lcool, querosene, nafta, g?soleos, etc., estes derivados s?o extra?dos de qualquer petr?leo, por?m, somente os com uma qualidade bastante elevada, ou seja, com teor de hidrocarbonetos de baixo peso molecular alto s?o realmente vi?veis a produ??o destes compostos. A American Petroleum Institute (API) desenvolveu um sistema de classifica??o dos tipos de petr?leo. No Brasil a qualidade da maioria dos petr?leos retirado dos po?os ? muito baixa, sendo assim, ? necess?rio obter novos conhecimentos a fim de desenvolver melhores pr?ticas de refino com o intuito de produzir derivados de petr?leo de alto valor comercial. Para isso se faz necess?rio o estudo de equil?brio termodin?mico de seus derivados. Esta disserta??o de mestrado consiste em determinar dados de equil?brio l?quido-vapor dos sistemas Fenilciclohexano - CO2 e Fenilciclohexano - Ciclohexano e CO2 a alta press?o e temperaturas entre 30 a 70 graus Celsius. Compara??es entres os dados experimentais de equil?brio liquidovapor encontrados no laborat?rio e na literatura foram realizadas em rela??o aos valores obtidos pelo modelo termodin?mico molecular de Peng-Robinson usando o programa computacional SPECS IVCSEP v5.60, com dois par?metros de intera??o ajust?veis, para fins de modelagem e simula??o. Al?m disso, ? apresentado o desenvolvimento de um equipamento de alta press?o no laborat?rio para determina??o de dados de equil?brio de fases

Made available in DSpace on 2014-12-17T15:01:44Z (GMT). No. of bitstreams: 1 JosiniraAA.pdf: 2069893 bytes, checksum: f72b269f6b8b693ef45bd7120dd46ee5 (MD5) Previous issue date: 2007-11-26 / The composition of petroleum may change from well to well and its resulting characteristics influence significantly the refine products. Therefore, it is important to characterize the oil in order to know its properties and send it adequately for processing. Since petroleum is a multicomponent mixture, the use of synthetic mixtures that are representative of oil fractions provides a better understand of the real mixture behavior. One way for characterization is usually obtained through correlation of physico-chemical properties of easy measurement, such as density, specific gravity, viscosity, and refractive index. In this work new measurements were obtained for density, specific gravity, viscosity, and refractive index of the following binary mixtures: n-heptane + hexadecane, cyclohexane + hexadecane, and benzene + hexadecane. These measurements were accomplished at low pressure and temperatures in the range 288.15 K to 310.95 K. These data were applied in the development of a new method of oil characterization. Furthermore, a series of measurements of density at high pressure and temperature of the binary mixture cyclohexane + n-hexadecane were performed. The ranges of pressure and temperature were 6.895 to 62.053 MPa and 318.15 to 413.15 K, respectively. Based on these experimental data of compressed liquid mixtures, a thermodynamic modeling was proposed using the Peng-Robinson equation of state (EOS). The EOS was modified with scaling of volume and a relatively reduced number of parameters were employed. The results were satisfactory demonstrating accuracy not only for density data, but also for isobaric thermal expansion and isothermal compressibility coefficients. This thesis aims to contribute in a scientific manner to the technological problem of refining heavy fractions of oil. This problem was treated in two steps, i.e., characterization and search of the processes that can produce streams with economical interest, such as solvent extraction at high pressure and temperature. In order to determine phase equilibrium data in these conditions, conceptual projects of two new experimental apparatus were developed. These devices consist of cells of variable volume together with a analytical static device. Therefore, this thesis contributed with the subject of characterization of hydrocarbons mixtures and with development of equilibrium cells operating at high pressure and temperature. These contributions are focused on the technological problem of refining heavy oil fractions / A composi??o do petr?leo pode variar de po?o para po?o e as suas caracter?sticas influenciam significativamente os produtos obtidos no processo de refino. Sendo assim, ? de suma import?ncia caracterizar o petr?leo para que se possam conhecer suas caracter?sticas e assim destin?-lo de maneira adequada para o seu processamento. Como o petr?leo ? uma mistura multicomponente, utilizar misturas sint?ticas representativas das fra??es proporciona um melhor entendimento do comportamento da mistura. Um caminho para a caracteriza??o de fra??es ? geralmente atrav?s de correla??o entre propriedades f?sicoqu?micas de f?cil medi??o em que algumas dessas propriedades como massa espec?fica, densidade, viscosidade e ?ndice de refra??o s?o freq?entemente utilizadas. Visando a caracteriza??o de fra??es de petr?leo, neste trabalho foram obtidos dados de massa espec?fica, viscosidade e ?ndice de refra??o de misturas bin?rias n-heptano + hexadecano, ciclohexano + hexadecano e benzeno + hexadecano em baixa press?o e temperaturas de 288,15 K a 310,95 K e esses dados foram utilizados no desenvolvimento de uma proposta de caracteriza??o de fra??es de fra??es de petr?leo atrav?s da rela??o de propriedades f?sico-qu?micas com a composi??o. Os resultados obtidos mostraram uma ferramenta promissora e flex?vel na caracteriza??o termof?sica de misturas de hidrocarbonetos. Adicionalmente, foi realizada a medi??o de massa espec?fica em alta press?o e temperatura da mistura bin?ria ciclohexano + n-hexadecano numa faixa de 6,895 a 62,053 MPa e 318,15 a 413,15 K e a partir desses dados, uma proposta de modelagem de densidade de l?quidos comprimidos utilizando o modelo de Peng-Robinson e escalonamento de volume foi desenvolvida, utilizando um n?mero menor de par?metros que outros modelos da literatura. Os resultados foram satisfat?rios mostrando a acur?cia do modelo n?o apenas para massa espec?fica, mas tamb?m para coeficiente de expans?o t?rmica e compressibilidade isot?rmica. Esta tese visou contribuir de maneira cientifica com o problema tecnol?gico de refino de ?leos pesados, que pode ser configurado como um problema de caracteriza??o e de busca de processos que possibilitem a obten??o de correntes fracionadas com interesse comercial, como por exemplo a extra??o com solventes em alta temperatura e press?o. Visando obter dados de equil?brio de fases nessas condi??es, foram desenvolvidos projetos conceituais de dois dispositivos experimentais, que consiste de uma c?lula de volume vari?vel como componente de um aparato de equil?brio est?tico anal?tico. Sendo assim, essa tese contribuiu com propostas de caracteriza??o de misturas de hidrocarbonetos e com projetos de montagem de uma c?lula de equil?brio operando em alta temperatura e alta press?o, o que pode contribuir para o problema tecnol?gico de refino de ?leos pesados

Made available in DSpace on 2014-12-17T14:08:54Z (GMT). No. of bitstreams: 1 HumbertoSC_DISSERT.pdf: 7792135 bytes, checksum: 5204c60825f60e9f74c5f24e46e8aa4e (MD5) Previous issue date: 2013-07-29 / Nearly 3 x 1011 m3 of medium and light oils will remain in reservoirs worldwide after conventional recovery methods have been exhausted and much of this volume would be recovered by Enhanced Oil Recovery (EOR) methods. The in-situ combustion (ISC) is an EOR method in which an oxygen-containing gas is injected into a reservoir where it reacts with the crude oil to create a high-temperature combustion front that is propagated through the reservoir. The High Pressure Air Injection (HPAI) method is a particular denomination of the air injection process applied in light oil reservoirs, for which the combustion reactions are dominant between 150 and 300?C and the generation of flue gas is the main factor to the oil displacement. A simulation model of a homogeneous reservoir was built to study, which was initially undergone to primary production, for 3 years, next by a waterflooding process for 21 more years. At this point, with the mature condition established into the reservoir, three variations of this model were selected, according to the recovery factors (RF) reached, for study the in-situ combustion (HPAI) technique. Next to this, a sensitivity analysis on the RF of characteristic operational parameters of the method was carried out: air injection rate per well, oxygen concentration into the injected gas, patterns of air injection and wells perforations configuration. This analysis, for 10 more years of production time, was performed with assistance of the central composite design. The reservoir behavior and the impacts of chemical reactions parameters and of reservoir particularities on the RF were also evaluated. An economic analysis and a study to maximize the RF of the process were also carried out. The simulation runs were performed in the simulator of thermal processes in reservoirs STARS (Steam, Thermal, and Advanced Processes Reservoir Simulator) from CMG (Computer Modelling Group). The results showed the incremental RF were small and the net present value (NPV) is affected by high initial investments to compress the air. It was noticed that the adoption of high oxygen concentration into the injected gas and of the five spot pattern tends to improve the RF, and the wells perforations configuration has more influence with the increase of the oil thickness. Simulated cases relating to the reservoir particularities showed that smaller residual oil saturations to gas lead to greater RF and the presence of heterogeneities results in important variations on the RF and on the production curves / Aproximadamente 3 x 1011 m3 de ?leos m?dios e leves restar?o nos reservat?rios ao redor do mundo ap?s a aplica??o dos m?todos convencionais de recupera??o e grande parte desse volume seria recuper?vel com o uso de m?todos especiais. A combust?o in-situ (CIS) ? um m?todo de recupera??o avan?ada de petr?leo no qual um g?s que cont?m oxig?nio ? injetado no reservat?rio onde reage com o ?leo cru para criar uma frente de combust?o de alta temperatura que se propaga pelo reservat?rio. O m?todo HPAI (High Pressure Air Injection) ? uma denomina??o particular do processo de inje??o de ar aplicado em reservat?rios de ?leos leves, onde as rea??es de combust?o s?o dominantes entre 150 e 300?C e a gera??o de flue gas ? o principal fator de deslocamento do ?leo. Um modelo de simula??o de fluxo de um reservat?rio homog?neo foi constru?do para o estudo, o qual foi inicialmente submetido ? produ??o prim?ria, por 3 anos, e em seguida, ao processo de inje??o de ?gua por mais 21 anos. Nesse ponto, com a condi??o madura estabelecida no reservat?rio, foram selecionadas tr?s varia??es desse modelo, de acordo com o fator de recupera??o (FR) obtido, para o estudo da t?cnica de combust?o in-situ (HPAI). Em seguida realizou-se uma an?lise de sensibilidade sobre o FR de par?metros operacionais pr?prios do m?todo: vaz?o de inje??o de ar por po?o, concentra??o de oxig?nio no g?s injetado, esquema de inje??o de ar e configura??o dos canhoneados dos po?os. Essa an?lise, para um per?odo adicional de at? 10 anos produ??o, foi efetuada com o aux?lio da t?cnica de planejamento composto central. O comportamento do reservat?rio e os impactos de par?metros envolvendo as rea??es qu?micas e de particularidades de reservat?rio sobre o FR tamb?m foram avaliados. Adicionalmente foram elaborados uma an?lise econ?mica e um estudo de maximiza??o do FR do processo. As simula??es foram realizadas com o simulador de processos t?rmicos em reservat?rios STARS (Steam, Thermal and Advanced Process Reservoir Simulation) da CMG (Computer Modelling Group). Os resultados mostraram que os FR incrementais foram baixos e que o valor presente l?quido (VPL) ? impactado negativamente pelos elevados investimentos iniciais para compress?o do ar. Observou-se que a ado??o de maiores concentra??es de oxig?nio no g?s injetado e do esquema de inje??o de ar tipo five spot tende a favorecer o FR, e que a configura??o dos canhoneados dos po?os apresenta influ?ncia crescente com o aumento da espessura porosa com ?leo do reservat?rio. Casos simulados referentes ?s particularidades de reservat?rio indicaram que menores satura??es residuais de ?leo ao g?s levam a FR maiores e que a exist?ncia de heterogeneidades resulta em varia??es consider?veis nos FR e nas curvas de produ??o