Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2017-04-03T19:41:30Z No. of bitstreams: 1 RafaelVianaSales_DISSERT.pdf: 3545507 bytes, checksum: 4ef61dd2d94d0034feabb461fc8913f1 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2017-04-05T19:14:13Z (GMT) No. of bitstreams: 1 RafaelVianaSales_DISSERT.pdf: 3545507 bytes, checksum: 4ef61dd2d94d0034feabb461fc8913f1 (MD5) / Made available in DSpace on 2017-04-05T19:14:13Z (GMT). No. of bitstreams: 1 RafaelVianaSales_DISSERT.pdf: 3545507 bytes, checksum: 4ef61dd2d94d0034feabb461fc8913f1 (MD5) Previous issue date: 2015-12-21 / A emiss?o de compostos sulfurados provenientes da queima de combust?veis derivados do refino do petr?leo, como ?leo diesel e gasolina, ? respons?vel por ocasionar danos ambientais, ? sa?de humana e aumento de custos industriais. Neste trabalho, foram estudados processos adsortivos de compostos sulfurados do diesel proveniente da Refinaria Potiguar Clara Camar?o, RPCC, com elevado teor de enxofre, utilizando s?licas mesoporosas do tipo MCM-41, que foram obtidas por m?todo hidrot?rmico, a partir de duas s?licas amorfas, s?lica MP1, novo material avaliado neste trabalho e uma s?lica comercial, utilizada para compara??o. Para os adsorventes mesoporosos MCM-41, sintetizados, foi avaliada a capacidade de adsor??o de enxofre em colunas de leito fixo e, posteriormente, os mesmos foram modificados, p?s-situ, com c?tions met?licos por impregna??o ?mida e dispers?o f?sica. Diferentes composi??es qu?micas dos compostos met?licos foram testadas, com a utiliza??o de ?xidos e sais, para a obten??o de s?tios ativos e avalia??o da complexa??o, entre o enxofre dos compostos org?nicos e os c?tions met?licos inseridos nos adsorventes, favorecendo a adsor??o. Os adsorventes sintetizados, puros e modificados, foram caracterizados atrav?s das t?cnicas de difratometria de raios X - DRX, espectroscopia de infravermelho com transformada de Fourier - FTIR, an?lises termogravim?tricas - TG/DTG, an?lises texturais pelo m?todo de BET/BJH e microscopia eletr?nica de varredura ? MEV com espectroscopia de energia dispersiva (EDS). Um planejamento fatorial do tipo 23, foi aplicado para o estudo do processo de adsor??o onde blends dos c?tions met?licos foram testados na adsor??o dos compostos sulfurados existentes. O monitoramento do teor de enxofre no diesel, durante o processo de adsor??o, ocorreu por t?cnica de Espectrometria de Fluoresc?ncia na Regi?o do Ultravioleta (FUV). A cin?tica e o equil?brio de adsor??o foram avaliados, onde isotermas de equil?brio foram obtidas para a avalia??o da capacidade m?xima de adsor??o de compostos sulfurados, nos sistemas adsorventes desenvolvidos neste trabalho. Foram obtidas capacidades m?ximas de adsor??o, em mg.g-1, de 16,64 e 14,98, respectivamente, para os adsorventes testados: 2AgS/MCM-41(M) e 1NiS1AgS/MCM-41(M). Os dados experimentais foram ajustados aos modelos de equil?brio de Langmuir e Freundlich. A remo??o de enxofre presente no diesel foi significante, atingindo o m?ximo de adsor??o de 94,9%, em rela??o ? concentra??o inicial deste contaminante. Atrav?s do estudo estat?stico, constatou-se que os blends preparados a partir dos adsorventes modificados por sais apresentaram uma capacidade de adsor??o maior em rela??o aos preparados por impregna??o de ?xidos met?licos, o que pode contribuir para a redu??o de custos industriais, uma vez que o m?todo de impregna??o ?mida dispensa uma segunda calcina??o. / The emission of sulfur compounds from the burning of oil products, such as diesel and gasoline, is responsible for causing environmental damage to human health and increase industrial costs. In this work, adsorptive processes of sulfur compounds from the diesel provided by the refinery Potiguar Clara Camar?o, RPCC, with high sulfur content, were studied using MCM-41 type of mesoporous silica which were obtained by hydrothermal method, from two amorphous silicas, MP1 silica, a new material evaluated in this work and a commercial silica, used for comparison. For MCM-41 mesoporous adsorbents, synthesized, it was evaluated the capability of sulfur adsorption in fixed bed columns, and later they were modified post-situ with metal cations by wet impregnation and physical dispersion. Different chemical compositions of metal compounds were tested with the use of oxides and salts, to obtain active sites and evaluation of complexing, between the sulfur of organic compounds and the metal cations inserted on the adsorbent, favoring adsorption. The synthesized adsorbents, pure and modified, were characterized by the techniques of X-ray diffraction - XRD, Fourier transform infrared spectroscopy - FTIR, thermogravimetric analysis - TG / DTG, textural analysis by the method of BET / BJH and scanning electron microscopy - SEM with energy dispersive spectroscopy (EDS). A 23 factorial plan was applied to study the adsorption process which metal cations blends were tested in the adsorption of existing sulfur compounds. The sulfur content monitoring in diesel fuel during the adsorption process occurred by ultraviolet fluorescence Spectrometry (UVF). The adsorption kinetics and equilibrium were evaluated, where equilibrium isotherms were obtained for the evaluation of the maximum adsorption capacity of sulfur compounds in adsorbent systems developed in this work. Maximum adsorption capacities were obtained ,at mg.g-1, 16,64 and 14,98, respectively, for the tested adsorbent: 2AgS/MCM-41(M) e 1NiS1AgS/MCM-41(M. The experimental data were fit to a Langmuir balance models and Freundlich. The removal of sulfur present in the diesel was significant, ranging from 54.3% to 88.9% compared to the initial concentration of contaminant. By statistical analysis it was found that blends prepared from the adsorbent modified by salts showed a higher adsorption capacity than the ones prepared by impregnation of metal oxides, which may contribute to the reduction of industrial costs, since the wet impregnation method dispenses a second calcination.

Made available in DSpace on 2014-12-17T15:41:59Z (GMT). No. of bitstreams: 1 Mariele ISM_DISSERT.pdf: 4704397 bytes, checksum: 9fa1538bc3d6948d492f9a6c378eaf62 (MD5) Previous issue date: 2012-07-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / Processo de Dessulfuriza??o Oxidativa (ODS) de um diesel comercial foi realizado em condi??es suaves na presen?a de catalisadores a base de van?dio ou mangan?s, suportados em aluminas, argilas e ze?litas. A oxida??o e extra??o da mol?cula de dibenzotiofeno (DBT), representando os compostos de enxofre presentes no diesel, foram realizadas usando como solvente a acetonitrila e oxidante o per?xido de hidrog?nio a temperatura de 55?C. O processo mostrou-se eficiente, o DBT foi convertido para sua respectiva sulfona, e a quantidade que n?o foi convertida a sulfona foi extra?da pelo solvente. O sistema de rea??o apresentou remo??o e oxida??o de at? 100% do composto de enxofre com alguns catalisadores. Verificando que para a oxida??o os catalisadores foram mais ativos, e os catalisadores de mangan?s apresentaram melhores resultados na extra??o dos compostos de enxofre.

Made available in DSpace on 2014-12-17T15:42:07Z (GMT). No. of bitstreams: 1 MarconiSFO_DISSERT.pdf: 4822002 bytes, checksum: 2debc2b37aed6dad6d1e0bb06a153e64 (MD5) Previous issue date: 2013-07-31 / The underground natural gas found associated or not with oil is characterized by a mixture of hydrocarbons and residual components such as carbon dioxide (CO2), nitrogen gas (N2) and hydrogen sulfide (H2S), called contaminants. The H2S especially promotes itself as a contaminant of natural gas to be associated with corrosion of pipelines, to human toxicity and final applications of Natural Gas (NG). The sulfur present in the GN must be fully or partially removed in order to meet the market specifications, security, transport or further processing. There are distinct and varied methods of desulfurization of natural gas processing units used in Natural Gas (UPGN). In order to solve these problems have for example the caustic washing, absorption, the use of membranes and adsorption processes is costly and great expenditure of energy. Arises on such findings, the need for research to active processes of economic feasibility and efficiency. This work promoted the study of the adsorption of sulfide gas in polymer matrices hydrogen pure and modified. The substrates of Poly(vinyl chloride) (PVC), poly(methyl methacrylate) (PMMA) and sodium alginate (NaALG) were coated with vanadyl phosphate compounds (VOPO4.2H2O), vanadium pentoxide (V2O5), rhodamine B (C28H31N2O3Cl) and ions Co2+ and Cu2+, aiming to the adsorption of hydrogen sulfide gas (H2S). The adsorption tests were through a continuous flow of H2S in a column system (fixed bed reactor) adsorption on a laboratory scale. The techniques used to characterize the adsorbents were Infrared spectroscopy (FTIR), thermogravimetry analysis (TGA), X-ray fluorescence (XRF), the X-ray diffraction (XRD) electron microscopy (SEM). Such work indicates, the results obtained, the adsorbents modified PMMA, PVC and NaALG have a significant adsorptive capacity. The matrix that stood out and had the best adsorption capacity, was to ALG modified Co2+ with a score of 12.79 mg H2S / g matrix / O g?s natural encontrado no subsolo associado ou n?o ao petr?leo se caracteriza por uma mistura de hidrocarbonetos e componentes residuais tais como o di?xido de carbono (CO2), o g?s nitrog?nio (N2) e o sulfeto de hidrog?nio (H2S), denominados de contaminantes. O H2S em especial se promove como contaminante do g?s natural por estar associado ? corros?o de dutos (gasodutos), ? toxidade humana e a aplica??es finais do G?s Natural (GN). O teor de enxofre presente no GN deve ser totalmente ou parcialmente removido, visando atender as especifica??es de mercado, seguran?a, transporte ou processamento posterior. H? distintos e variados m?todos de dessulfuriza??o do g?s natural usados nas Unidades de Processamento do G?s Natural (UPGN). Visando solucionar tais problemas temos como exemplo a lavagem c?ustica, a absor??o, o uso de membranas e a adsor??o, sendo processos onerosos e com grande disp?ndio energ?tico. Surge, diante de tais constata??es, a necessidade de pesquisa de processos ativos de viabilidade econ?mica e efici?ncia. O presente trabalho promoveu o estudo da adsor??o do g?s sulfeto de hidrogr?nio em matrizes polim?ricas puras e modificadas. Os substratos de Poli(cloreto de vinila) (PVC), Poli(metacrilato de metila) (PMMA) e alginato de s?dio (NaALG), foram recobertos com os compostos de fosfato de vanadila (VOPO4.2H2O), pent?xido de van?dio (V2O5), rodamina B (C28H31N2O3Cl) e os ?ons Co2+ e Cu2+, objetivando-se a adsor??o do g?s sulfeto de hidrog?nio (H2S). Os ensaios de adsor??o se deram atrav?s de um fluxo cont?nuo de H2S em um sistema de coluna (reator de leito fixo) de adsor??o em escala de laborat?rio. As t?cnicas utilizadas para a caracteriza??o dos adsorventes foram ? espectroscopia de infravermelho (FTIR), a an?lise termogravimetria (TG), a fluoresc?ncia de raios X (FRX), o difra??o de raios X (DRX), a microscopia eletr?nica de varredura (MEV). Tal trabalho indica, pelos resultados obtidos, que os adsorventes modificados de PMMA, PVC e NaALG t?m uma capacidade adsortiva significativa. A matriz que se destacou e apresentou a melhor capacidade de adsor??o, foi a de ALG modificada com Co2+ tendo um resultado de 12,79 mg de H2S/g de matriz

Made available in DSpace on 2014-12-17T15:41:53Z (GMT). No. of bitstreams: 1 JoseABLRA_DISSERT.pdf: 2347923 bytes, checksum: 6e0dcb6d004a500ef5b9305459cc4e95 (MD5) Previous issue date: 2010-05-27 / Mesoporous molecular sieves of MCM-41 type are considered as promising support for metal in the refining processes of petroleum-based materials as catalysts and adsorbents for environmental protection. In this work, mesoporous molecular sieves MCM-41 were modified with different rare earth ions (La, Eu e Yb) for the obtaining nanostrutured materials with catalytic properties. The catalysts were synthesized by the hydrothermal method at 100oC for 120 h, presenting, all the samples, in the gel of synthesis molar ratio Si/Ln = 50. The obtained materials after calcination at 500oC for 2 h were characterized by XRD, surface area BET, TG/DTG, FTIR, and hydrothermal stability at 700?C. The XRD analysis of the catalysts indicated that the materials containing rare earth presented characteristic hexagonal structure of the mesoporous materials of the type MCM-41. The TG curves showed that the decomposition of the structural template occurs in the materials at temperatures lower than 500oC. The samples presented variations as the specific superficial area, average diameter of pores and thickness of the silica wall, as a function of the nature of the rare earth impregnated in the mesoporous material. Hydrotermal stability was evaluated through the exposition of the materials to water vapour at 700?C. The thiophene adsorptions reach a maximum at 80% of conversion and incorporation of the rare earths showed influence in the process. Adsorption capacity followed the sequence: Yb-MCM-41 < La-MCM-41 < Eu-MCM-41 < MCM-41 / As peneiras moleculares mesoporosas do tipo MCM-41 s?o consideradas promissoras como suporte para metais em processos de refino de materiais a base de petr?leo, como catalisadores e como adsorventes para prote??o ambiental. Neste trabalho a peneira molecular mesoporosa tipo MCM-41 foi modificada com diferentes terras raras (La, Eu e Yb) para a obten??o de materiais nanoestruturados com propriedades catal?ticas. Os catalisadores foram sintetizados pelo m?todo hidrot?rmico a 100 oC por 120 horas, apresentando, todas as amostras, no gel de s?ntese raz?o molar Si/Ln = 50. Os materiais resultantes, ap?s calcina??o a 500 oC por 2 horas, foram caracterizados por: DRX, ?rea superficial pelo m?todo de BET, TG/DTG, FTIR e testes hidrot?rmicos a 700oC. As an?lises de DRX dos catalisadores indicaram que os materiais contendo as terras raras apresentaram estrutura hexagonal caracter?stica do material mesoporoso tipo MCM-41. As curvas TG mostraram que a decomposi??o do direcionador estrutural ocorre nos materiais em temperaturas inferiores a 500oC. As amostras apresentaram varia??es quanto ? ?rea superficial espec?fica, di?metro m?dio de poros e espessura da parede de s?lica, em fun??o da natureza da terra rara impregnada no material mesoporoso. A estabilidade hidrot?rmica foi avaliada atrav?s da exposi??o dos materiais a vapor d ?gua a 700oC. A adsor??o de tiofeno atingiu valores m?ximos de 80% e a incorpora??o das terras raras influenciaram no processo. A ordem crescente de capacidade de adsor??o seguiu a seguinte seq??ncia: Yb-MCM-41 < La-MCM-41 < Eu-MCM-41 < MCM-41

Made available in DSpace on 2014-12-17T15:42:00Z (GMT). No. of bitstreams: 1 Mariele ISM_DISSERT.pdf: 4704397 bytes, checksum: 9fa1538bc3d6948d492f9a6c378eaf62 (MD5) Previous issue date: 2012-07-20 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The oxidative desulfurization process (ODS) of a commercial diesel fuel was performed under mild conditions in the presence of catalysts based on vanadium or manganese, supported on alumina, clays (commercial, natural and pillared) and zeolites (NaX, NaY, beta, mordenite and ZSM-5). The catalysts were synthesized by wet impregnation and characterized by X-ray diffraction, textural analysis by N2 adsorption and scanning electron microscopy. The dibenzothiophene (DBT) was used as sulfur compound in catalytic evaluation. The reactions were performed using acetonitrile as solvent and the hydrogen peroxide as oxidant at 55?C. The reaction products were analized by gas chromatography (GC-FID). In the studied conditions, the process was efficient due to the DBT was converted to its corresponding sulfone. Both DBT and corresponding sulfone were extracted by the solvent. Removals and oxidations up to 100% of sulfur compound were achieved. The catalysts supported on ZSM-5 zeolite showed are more effective for oxidation reaction of sulfur compound, presenting the best results. It was observed for oxidation reaction, that vanadium catalysts were more effective and manganese catalysts showed best results for removal of sulfur compounds / O processo de Dessulfuriza??o Oxidativa (ODS) de um diesel comercial foi realizado em condi??es suaves na presen?a de catalisadores ? base de van?dio ou mangan?s, suportados em aluminas, argilas (comerciais, naturais e pilarizadas) e ze?litas (NaX, NaY, beta, mordenita, ZSM-5). Os catalisadores foram sintetizados via impregna??o ?mida e caracterizados por difra??o de raios-X, an?lise textural por adsor??o e dessor??o de nitrog?nio e microscopia eletr?nica de varredura. O dibenzotiofeno (DBT) foi utilizado como o composto de enxofre nos testes catal?ticos. As rea??es foram realizadas usando como solvente acetonitrila e como oxidante o per?xido de hidrog?nio a temperatura de 55?C. Os produtos de rea??o foram analisados por cromatografia gasosa (CG-FID). Nas condi??es estudadas o processo mostrouse eficiente, o DBT foi convertido para sua respectiva sulfona. Ambos DBT e a sulfona foram extra?dos pelo solvente. Remo??es e oxida??es de 100% do composto de enxofre foram alcan?adas. Os catalisadores suportados na ze?lita ZSM-5 mostraram-se mais efetivos para a rea??o de oxida??o do composto sulfurado, apresentando os melhores resultados. Observa-se para a rea??o de oxida??o que os catalisadores de van?dio foram mais efetivos, e os catalisadores de mangan?s apresentaram melhores resultados na extra??o dos compostos sulfurados

Submitted by Jorge Silva (jorgelmsilva@ufrrj.br) on 2017-05-09T20:05:40Z No. of bitstreams: 1 2016 - Melise Ferreira de Aguiar.pdf: 5763969 bytes, checksum: 9dcc7682d7ffab0b0a6ce4d1db704c10 (MD5) / Made available in DSpace on 2017-05-09T20:05:40Z (GMT). No. of bitstreams: 1 2016 - Melise Ferreira de Aguiar.pdf: 5763969 bytes, checksum: 9dcc7682d7ffab0b0a6ce4d1db704c10 (MD5) Previous issue date: 2016-12-12 / CAPES / Natural gas is extensively used in industries as well as in other sectors as an energy resource and, sometimes, it needs to undergo processes for the removal of impurities present in its composition. Among them are the sulfur compounds, which can cause damages to pipes and catalysts, making it necessary to develop and/or improve deep desulfurization methods. In this context, granular activated carbon was modified through two methods, oxidation using nitric acid, and impregnation using a ferric chloride solution. The resulting adsorbents were evaluated for their capacity of adsorbing seven sulfur compounds present in the synthetic natural gas sample, through their rupture curves. Afterwards, the adsorbents desorption was performed by using supercritical carbon dioxide under the conditions of 60?C at 100 bar, 150 bar and 200 bar. The results indicate that all the modification methods improved the sulfur compounds retention when compared to virgin activated carbon. The compound that had the greatest increase in the adsorption capacity after iron impregnation was the tert-butyl mercaptan (TBM), and with the activated carbon oxidized by HNO3 it was the dimethyl sulfide (DMS). Nevertheless, the supercritical conditions studied in the desorption stage were efficient only for the unmodified activated carbon. The adsorption capacities of both modified adsorbents after the regeneration were inferior to those capacities obtained in the first adsorption, then two hypotheses were investigated: (1) destruction of the newly created sites after regeneration; and (2) incomplete desorption in the studied supercritical conditions. Through other experiments it was proved that, after regeneration, there was no destruction of the newly created sites; therefore, further studies on the operating conditions are required in order to the modified adsorbents to achieve high regeneration capacities. / O g?s natural ? utilizado nas ind?strias e em outros setores como fonte de energia e necessita, por vezes, de processos de remo??o das impurezas presentes em sua composi??o. Dentre elas est?o os compostos de enxofre, que provocam danos em tubula??es e catalisadores, sendo necess?rio o desenvolvimento e/ou o aperfei?oamento de m?todos para a dessulfuriza??o profunda. Nesse contexto, um carv?o ativado granular foi modificado por meio de dois m?todos, oxida??o utilizando ?cido n?trico e por impregna??o usando uma solu??o de cloreto de ferro III, os adsorventes resultantes foram avaliados quanto ? sua capacidade para adsorver sete compostos de enxofre presentes em uma amostra de g?s natural sint?tica, atrav?s das curvas de rupturas. Posteriormente, foi realizada a dessor??o dos adsorventes utilizando di?xido de carbono supercr?tico nas condi??es de 60 ?C a 100 bar, 150 bar e 200 bar. Os resultados indicam que todos os m?todos de modifica??o melhoraram a reten??o dos compostos sulfurados individuais em compara??o com o carv?o ativado virgem. O composto que obteve maior aumento da capacidade de adsor??o ap?s a impregna??o com ferro foi o terc-butilmercaptana (TBM), e com o carv?o ativado oxidado pelo HNO3 foi o metiletilsulfeto (DMS). J? as condi??es supercr?ticas estudadas na etapa de dessor??o foram eficientes somente para o carv?o ativado n?o modificado. As capacidades de adsor??o dos dois adsorventes modificados ap?s a regenera??o foram inferiores aos obtidos na primeira adsor??o, ent?o duas hip?teses foram investigadas: (1) destrui??o dos novos s?tios criados ap?s a regenera??o; e (2) dessor??o incompleta nas condi??es supercr?ticas estudadas. Atrav?s de outros experimentos comprovou-se que n?o houve ? destrui??o dos novos s?tios criados ap?s a regenera??o, sendo necess?rio um estudo mais profundo em rela??o ?s condi??es operacionais, a fim de alcan?ar altas capacidades de regenera??o dos adsorventes modificados.

Made available in DSpace on 2014-12-17T14:07:01Z (GMT). No. of bitstreams: 1 KarlaSMGS_partes_autorizadas_pelo_autor.pdf: 1248832 bytes, checksum: 6139c9f98f965322e719dfe4f7274a99 (MD5) Previous issue date: 2009-03-13 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The mixed metal oxides constitute an important class of catalytic materials widely investigated in different fields of applications. Studies of rare earth nickelates have been carried by several researchers in order to investigate the structural stability afforded by oxide formed and the existence of catalytic properties at room temperature. So, this study aims synthesize the nanosized catalyst of nickelate of lanthanum doped with strontium (La(1-x)SrxNiO4-d; x = 0,2 and 0,3), through the Pechini method and your characterization for subsequent application in the desulfurization of thiophene reaction. The precursor solutions were calcined at 300?C/2h for pyrolysis of polyester and later calcinations occurred at temperatures of 500 - 1000?C. The resulting powders were characterized by thermogravimetric analysis (TG / DTG), surface area for adsorption of N2 by BET method, X-ray diffraction (XRD), scanning electron microscopy (HR_SEM) and spectrometry dispersive energy (EDS). The results of XRD had show that the perovskites obtained consist of two phases (LSN and NiO) and from 700?C have crystalline structure. The results of SEM evidenced the obtainment of nanometric powders. The results of BET show that the powders have surface area within the range used in catalysis (5-50m2/g). The characterization of active sites was performed by reaction of desulfurization of thiophene at room temperature and 200?C, the relation F/W equal to 0,7 mol h-1mcat -1. The products of the reaction were separated by gas chromatography and identified by the selective detection PFPD sulfur. All samples had presented conversion above 95% / Os ?xidos met?licos mistos constituem uma importante classe de materiais catal?ticos mundialmente investigados em diferentes campos de aplica??es. Estudos envolvendo niquelatos de terras raras v?m sendo realizados por v?rios pesquisadores no intuito de investigar a estabilidade proporcionada pelo ?xido estrutural formado e a exist?ncia de propriedades catal?ticas, ? temperatura ambiente. Neste contexto, este trabalho tem como objetivo a s?ntese do catalisador nanom?trico de niquelato de lant?nio dopado com estr?ncio (La(1-x)SrxNiO4-d; x = 0,2 e 0,3), atrav?s do m?todo Pechini e caracteriza??o para posterior aplica??o em rea??o de dessulfuriza??o de tiofeno. As solu??es precursoras foram calcinadas a 300?C/2h, para pir?lise do poli?ster e posteriores calcina??es foram realizadas nas temperaturas entre 500 - 1000?C. Os p?s resultantes foram caracterizados por an?lise termogravim?trica (TG/DTG), ?rea superficial por adsor??o de N2 pelo m?todo BET, difra??o de raios x (DRX), microscopia eletr?nica de varredura de alta resolu??o (HR_MEV) e espectroscopia por energia dispersiva (EDS). Com os dados de an?lise t?rmica, foi poss?vel definir as temperaturas e calores envolvidos no processo de decomposi??o dos ?xidos finais. Os resultados de DRX mostraram que as perovisquitas obtidas s?o constitu?das de duas fases (LSN e NiO) e a partir de 700?C apresentaram estrutura cristalina. Os resultados de MEV evidenciaram a obten??o de p?s nanom?tricos. Os resultados de BET mostraram que os p?s obtidos apresentam ?rea superficial dentro da faixa utilizada em cat?lise (5-50m2/g). A caracteriza??o dos s?tios ativos foi realizada atrav?s da rea??o de dessulfuriza??o de tiofeno ? temperatura ambiente e a 200oC, com raz?o F/W igual a 0,7molh-1mcat -1. Os produtos da rea??o foram separados por cromatografia em fase gasosa e identificados por detec??o PFPD seletivo a enxofre. Todas as amostras apresentaram convers?o acima de 95%

Made available in DSpace on 2014-12-17T15:01:19Z (GMT). No. of bitstreams: 1 LuizFSF.pdf: 1747527 bytes, checksum: e75c5e8a2575620cc3a29490253bcad6 (MD5) Previous issue date: 2009-03-05 / Natural gas, although basically composed by light hydrocarbons, also presents in its composition gaseous contaminants such as CO2 (carbon dioxide) and H2S (hydrogen sulfide). Hydrogen sulfide, which commonly occurs in oil and gas exploration and production activities, besides being among the gases that are responsible by the acid rain and greenhouse effect, can also cause serious harm to health, leading even to death, and damages to oil and natural gas pipelines. Therefore, the removal of hydrogen sulfide will significantly reduce operational costs and will result in oil with best quality to be sent to refinery, thereby resulting in economical, environmental, and social benefits. These factors highlight the need for the development and improvement of hydrogen sulfide sequestrating agents to be used in the oil industry. Nowadays there are several procedures for hydrogen sulfide removal from natural gas used by the petroleum industry. However, they produce derivatives of amines that are harmful to the distillation towers, form insoluble precipitates that cause pipe clogging and produce wastes of high environmental impact. Therefore, the obtaining of a stable system, in inorganic or organic reaction media, that is able to remove hydrogen sulfide without forming by-products that affect the quality and costs of natural gas processing, transport and distribution is of great importance. In this context, the evaluation of the kinetics of H2S removal is a valuable procedure for the treatment of natural gas and disposal of the byproducts generated by the process. This evaluation was made in an absorption column packed with Raschig ring, where natural gas with H2S passes through a stagnant solution, being the contaminant absorbed by it. The content of H2S in natural gas in column output was monitored by an H2S analyzer. The comparison between the obtained curves and the study of the involved reactions have not only allowed to determine the efficiency and mass transfer controlling step of the involved processes but also make possible to effect a more detailed kinetic study and evaluate the commercial potential of each reagent / O g?s natural, embora seja composto basicamente de hidrocarbonetos leves, apresenta tamb?m em sua composi??o gases contaminantes como o CO2 (Di?xido de carbono) e o H2S (Sulfeto de hidrog?nio). O H2S, que comumente ocorre nas atividades de explora??o e produ??o de ?leo e g?s, al?m de estar entre os respons?veis pela chuva ?cida e pelo efeitoestufa, causa s?rios danos ? sa?de, levando inclusive ? morte, e danifica as tubula??es de transporte do petr?leo e do g?s natural. Por isso, eliminando-se o g?s sulf?drico haver? significativa redu??o dos custos de opera??o e uma melhor qualidade do ?leo destinado ? refinaria, resultando assim num beneficio econ?mico, ambiental e social. Tudo isso demonstra a necessidade do desenvolvimento e aprimoramento de seq?estrantes que removam o sulfeto de hidrog?nio da ind?stria de petr?leo. Atualmente existem v?rios processos para o tratamento do g?s natural utilizados pela ind?stria petrol?fera para remo??o do H2S, no entanto eles produzem derivados de aminas prejudiciais ?s torres de destila??o, precipitados insol?veis que provocam entupimento dos dutos e originam res?duos de grande impacto ambiental. Por isso, a obten??o de um sistema est?vel em meio reacional inorg?nico ou org?nico capaz de remover o g?s sulf?drico sem formar subprodutos que afetem a qualidade e o custo do processamento, transporte e distribui??o do g?s natural ? de grande import?ncia. Nesse contexto a avalia??o da cin?tica de remo??o do H2S surge como um procedimento valioso para o tratamento do g?s natural e destino dos subprodutos do processo. Esta avalia??o foi feita numa coluna de absor??o recheada com an?is de Raschig, por onde o g?s natural contaminado com H2S atravessava uma solu??o estagnada, sendo por esta absorvida. Na sa?da da coluna o teor de H2S no g?s era monitorado por um analisador de H2S. A compara??o das curvas obtidas e o estudo das rea??es permitiram n?o somente determinar a efici?ncia e a etapa controladora da transfer?ncia de massa dos processos envolvidos como tamb?m efetuar um estudo cin?tico mais aprofundado e avaliar o potencial comercial de cada reagente