La régénération et la réactivation des catalyseurs industriels d'hydrodésulfuration (HDS) CoMo/Al2O3 usés permettent leur réutilisation. Étant donné que ces catalyseurs sont considérés comme toxiques et polluants, la régénération/réactivation est une procédure intéressante dans un cadre écologique et économique. La régénération permet d'éliminer les dépôts de carbone mais ne permet pas de restaurer complètement l'activité des catalyseurs de HDS des nouvelles générations. En conséquence, une deuxième étape appelée « réjuvenation », impliquant l’ajout de composés organiques, a été mise en œuvre. L’étude de l’impact des additifs est d’un grand intérêt mais de nombreuses observations restent inexpliquées. En outre, certains brevets ont décrit une procédure de pré-activation permettant d'activer des catalyseurs ex situ afin d'éviter le contact avec des composés soufrés, ainsi que de manipuler et de charger en toute sécurité les catalyseurs dans des unités de HDS. De plus, il est de notoriété publique que la sulfuration est une étape critique ayant un impact important sur les performances catalytiques. En ce sens, cette étude vise à étudier l’effet de différentes conditions de rajeunissement, de pré-activation et de sulfuration ultérieure sur les caractéristiques finales des catalyseurs. Dans ce travail, trois catalyseurs régénérés et pré-activés ont été étudiés après différents protocoles de sulfuration. Les catalyseurs ont été testés et comparés dans la HDS de thiophène et SRGO. Aussi, l’influence des composés organiques ajoutés lors de la réjuvenation a été étudiée par différentes techniques (XPS, CO / IR, TEM…). Les résultats ont permis de déterminer les différences d'activité catalytique et d'établir une corrélation entre l'activité en HDS du thiophène et la concentration de sites CoMoS. Aucune divergence morphologique n'a été détectée dans les systèmes et les différences de performances catalytiques sont attribuées à un degré de promotion inégal. / Regeneration and reactivation of used industrial CoMo/Al2O3 hydrodesulfurization (HDS) catalysts allows reusing them. Since these catalysts are considered toxic and pollutant, regeneration/reactivation is an interesting procedure from an economical and ecological point of view. The regeneration allows removing carbon deposits but, by itself, does not restore completely the activity of new generations of HDS catalysts. Consequently, a second stage named rejuvenation, involving addition of organic compounds has been implemented. The study of the impact of additives is of great interest but many observations remain unexplained. Furthermore, some patents have described a pre-activation procedure that allows activating catalysts ex situ in order to avoid contact with sulfur compounds and a safe handling and loading of the catalysts in HDS units. In addition, it is common knowledge that sulfidation is a critical stage that impacts strongly the catalytic performance. In this sense, this study aims to study the effect of different rejuvenation, pre-activation and subsequent sulfidation conditions on final characteristics of catalysts. In this work three rejuvenated and pre-activated catalysts were studied after different sulfidation protocols. Catalysts were tested and compared in thiophene and SRGO HDS. Additionally, the influence of the organic compounds added during rejuvenation was studied by different techniques (XPS, CO/IR, TEM…). Results allowed determining differences in catalytic activity and establishing a correlation between thiophene HDS activity and CoMoS concentration. No morphological divergences were detected in the systems, instead, differences in catalytic performances are attributed to an unequal promotion degree

Orientador: Mauro Gonçalves / Banca: Júlio Cerca Serrão / Banca: Camila Coelho Greco / Resumo: O presente estudo teve como objetivo verificar se as intensidades do LFEMG e do ponto de quebra são semelhantes e se há diferença no valor do índice, calculando-se o RMS em intervalos referentes a cinco segundos ou ao ciclo de passada e estudar o comportamento da freqüência de passada (FP), amplitude (RMS) e freqüência da atividade eletromiográfica nos período pré (RMS-PRE, FM-PRE) e pós contato (RMS-PRE, FM-POS) dos músculos íleocostal (IC), reto femoral (RF), vasto lateral (VL), vasto medial (VM), bíceps femoral (BF), tibial anterior (TA) e gastrocnêmio lateral (GL), bem como da co-ativação dos músculos RF/BF, VL/BF, VM/BF e GL/TA nos períodos pré (PRE) e póscontato (POS) ao longo de um teste incremental, considerando as intensidades absolutas e quatro intensidades relativas: inicial (IIN), equivalente ao LFEMG (ILF), 15% abaixo (IAB) e 15% acima (IAC) do LFEMG. Onze voluntários foram submetidos a um teste incremental de corrida até exaustão voluntária. Os valores de RMS foram obtidos de duas formas, a cada cinco segundos do intervalo de corrida e a cada ciclo de passada. O LFEMG e o ponto de quebra foram determinados. Não houve diferenças significantes entre os valores dos índices obtidos pelas duas formas de análise nem entre os músculos. Entretanto, foi evidenciado que os valores de LFEMG foram maiores do que os do ponto de quebra apenas quando determinados pelos valores de RMS obtidos nos ciclos de passada. As velocidades relativas obtidas foram 9,2±0,4 km.h-1 na IAB, 10,6±0,7 km.h-1 na LFEMG e 12,3±0,5 km.h-1 na IAC. A partir dos 11 km.h-1 a FP, a RMS-PRE para o músculo IC e a RMS-POS para os músculos VL e VM apresentaram aumento. Nas intensidades relativas, houve aumento dos valores da FP, da RMS-PRE para os músculos BF, TA e GL, da RMS-POS e FM-POS para o músculo GL a partir da ILF. As correlações foram significantes para FP e FM-PRE do VL... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: The aim of the present study was to verify whether eletromyographic fatigue threshold (EMGFT) and breakpoint intensities were similar and whether there is differences in the speed value between these indexes when calculated considering five seconds intervals or referent to stride cycle and study stride frequency (SF), amplitude and frequency of electromyographic activity behaviors on pre (PRE) and post (POS) contact periods for iliocostalis (IC), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), tibialis anterior (TA) and gastrocnemius lateralis (GL), and co-activation ratio of RF/BF, VL/BF, VM/BF and GL/TA on PRE and POST periods during an incremental running protocol, considering absolute intensities and four relative intensities: initiail (IIN), equivalent to EMGFT (IFT), 15% below (IBE) and 15% above (IAB) EMGFT. Eleven males performed an incremental running test to exhaustion. RMS values were obtained every five seconds and during stride cycles of each running stage. EMGFT and breakpoint were determined for all muscles. There were no significant differences between two different indexes when calcula values obtained RMS calculation nor among different muscles. However, the EMGFT values were greater than breakpoint values when determined using RMS calculated for stride cycles, with no difference when obtained every five seconds. Relative intensities obtained were 9.2±0.4 km... (Complete abstract click electronic access below) / Mestre

Made available in DSpace on 2014-06-11T19:22:52Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-03-11Bitstream added on 2014-06-13T19:28:21Z : No. of bitstreams: 1 silva_pb_me_rcla.pdf: 790741 bytes, checksum: d5249659f04bcedba18543a60ee45546 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / O presente estudo teve como objetivo verificar se as intensidades do LFEMG e do ponto de quebra são semelhantes e se há diferença no valor do índice, calculando-se o RMS em intervalos referentes a cinco segundos ou ao ciclo de passada e estudar o comportamento da freqüência de passada (FP), amplitude (RMS) e freqüência da atividade eletromiográfica nos período pré (RMS-PRE, FM-PRE) e pós contato (RMS-PRE, FM-POS) dos músculos íleocostal (IC), reto femoral (RF), vasto lateral (VL), vasto medial (VM), bíceps femoral (BF), tibial anterior (TA) e gastrocnêmio lateral (GL), bem como da co-ativação dos músculos RF/BF, VL/BF, VM/BF e GL/TA nos períodos pré (PRE) e póscontato (POS) ao longo de um teste incremental, considerando as intensidades absolutas e quatro intensidades relativas: inicial (IIN), equivalente ao LFEMG (ILF), 15% abaixo (IAB) e 15% acima (IAC) do LFEMG. Onze voluntários foram submetidos a um teste incremental de corrida até exaustão voluntária. Os valores de RMS foram obtidos de duas formas, a cada cinco segundos do intervalo de corrida e a cada ciclo de passada. O LFEMG e o ponto de quebra foram determinados. Não houve diferenças significantes entre os valores dos índices obtidos pelas duas formas de análise nem entre os músculos. Entretanto, foi evidenciado que os valores de LFEMG foram maiores do que os do ponto de quebra apenas quando determinados pelos valores de RMS obtidos nos ciclos de passada. As velocidades relativas obtidas foram 9,2±0,4 km.h-1 na IAB, 10,6±0,7 km.h-1 na LFEMG e 12,3±0,5 km.h-1 na IAC. A partir dos 11 km.h-1 a FP, a RMS-PRE para o músculo IC e a RMS-POS para os músculos VL e VM apresentaram aumento. Nas intensidades relativas, houve aumento dos valores da FP, da RMS-PRE para os músculos BF, TA e GL, da RMS-POS e FM-POS para o músculo GL a partir da ILF. As correlações foram significantes para FP e FM-PRE do VL... / The aim of the present study was to verify whether eletromyographic fatigue threshold (EMGFT) and breakpoint intensities were similar and whether there is differences in the speed value between these indexes when calculated considering five seconds intervals or referent to stride cycle and study stride frequency (SF), amplitude and frequency of electromyographic activity behaviors on pre (PRE) and post (POS) contact periods for iliocostalis (IC), rectus femoris (RF), vastus lateralis (VL), vastus medialis (VM), biceps femoris (BF), tibialis anterior (TA) and gastrocnemius lateralis (GL), and co-activation ratio of RF/BF, VL/BF, VM/BF and GL/TA on PRE and POST periods during an incremental running protocol, considering absolute intensities and four relative intensities: initiail (IIN), equivalent to EMGFT (IFT), 15% below (IBE) and 15% above (IAB) EMGFT. Eleven males performed an incremental running test to exhaustion. RMS values were obtained every five seconds and during stride cycles of each running stage. EMGFT and breakpoint were determined for all muscles. There were no significant differences between two different indexes when calcula values obtained RMS calculation nor among different muscles. However, the EMGFT values were greater than breakpoint values when determined using RMS calculated for stride cycles, with no difference when obtained every five seconds. Relative intensities obtained were 9.2±0.4 km... (Complete abstract click electronic access below)