• Refine Query
  • Source
  • Publication year
  • to
  • Language
  • 3
  • Tagged with
  • 3
  • 3
  • 3
  • 2
  • 2
  • 2
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • 1
  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

Pir?lise t?rmica e catal?tica de res?duos de v?cuo gerados no refino de petr?leo

Lima, Regineide de Oliveira 17 February 2012 (has links)
Made available in DSpace on 2014-12-17T14:08:50Z (GMT). No. of bitstreams: 1 RegineideOL_DISSERT.pdf: 1906684 bytes, checksum: 6ab6bc4b30db454754e3cd6ba142d8d7 (MD5) Previous issue date: 2012-02-17 / In this study, was used a very promising technique called of pyrolysis, which can be used for obtaining products with higher added value. From oils and residues, since the contribution of heavier oils and residues has intensified to the world refining industry, due to the growing demand for fuel, for example, liquid hydrocarbons in the range of gasoline and diesel. The catalytic pyrolysis of vacuum residues was performed with the use of a mesoporous material belonging the M41S family, which was discovered in the early 90s by researchers Mobil Oil Corporation, allowing new perspectives in the field of catalysis. One of the most important members of this family is the MCM-41, which has a hexagonal arrangement of mesopores with pore diameters between 2 and 10 nm and a high specific surface area, making it very promising for use as a catalyst in petroleum refining for catalytic cracking, and their mesopores facilitate the access of large hydrocarbon molecules. The addition of aluminum in the structure of MCM-41 increases the acidity of the material, making it more positive for application in the petrochemical industry. The mesoporous material of the type Al-MCM41 (ratio Si / Al = 50) was synthesized by hydrothermal method starting from the silica gel, NaOH and distilled water added to the gel pseudobohemita synthesis. Driver was used as structural CTMABr. Removal of organic driver (CTMABr) was observed by TG / DTG and FTIR, but this material was characterized by XRD, which was observed the formation of the main peaks characteristic of mesoporous materials. The analysis of adsorption / desorption of nitrogen this material textural parameters were determined. The vacuum residues (VR's) that are products of the bottom of the vacuum distillation tower used in this study are different from oil fields (regions of Cear? and Rio de Janeiro). Previously characterized by various techniques such as FTIR, viscosity, density, SARA, elemental analysis and thermogravimetry, which was performed by thermal and catalytic degradation of vacuum residues. The effect of AlMCM-41 was satisfactory, since promoted a decrease in certain ranges of temperature required in the process of conversion of hydrocarbons, but also promoted a decrease in energy required in the process. Thus enabling lower costs related to energy expenditure from degradation during processing of the waste / No presente trabalho, foi utilizada uma t?cnica bastante promissora denominada de pir?lise, a qual pode ser usada para obten??o de produtos com maior valor agregado. Partindo de ?leos e res?duos, visto que a contribui??o desses petr?leos mais pesados e res?duos tem se intensificado para o mundo da ind?stria do refino, em virtude da crescente demanda por combust?veis, como por exemplo, hidrocarbonetos l?quidos na faixa de gasolina e ?leo diesel. Os res?duos de v?cuo (RV?S) que s?o produtos de fundo da torre de destila??o a v?cuo utilizados neste trabalho, foram provenientes de diferentes petr?leos (regi?es do Cear? e Rio de Janeiro). Estes res?duos foram previamente caracterizados por v?rias t?cnicas como: FTIR, viscosidade, densidade, SARA, an?lise elementar e termogravimetria, pela qual foi realizada a degrada??o t?rmica e catal?tica dos res?duos de v?cuo. A pir?lise catal?tica dos res?duos de v?cuo foi realizada com a utiliza??o de um material mesoporoso pertencente ? fam?lia M41S, que foi descoberto no in?cio dos anos 90 por pesquisadores da Mobil Oil Corporation, possibilitando assim novas perspectivas no ramo da cat?lise. Um dos mais importantes membros desta fam?lia ? o MCM-41, que possui um arranjo hexagonal de mesoporos com di?metros de poros entre 2 a 10 nm e uma alta ?rea espec?fica, tornando-o bastante promissor para ser utilizado como catalisador no refino do petr?leo para o craqueamento catal?tico, j? que seus mesoporos facilitam o acesso de mol?culas grandes de hidrocarbonetos. A incorpora??o do alum?nio na rede do material MCM-41 proporciona a acidez ao material, possibilitando sua aplica??o na ind?stria petroqu?mica. O material mesoporoso do tipo Al- MCM41 (raz?o Si/Al=50) foi sintetizado atrav?s do m?todo hidrot?rmico partindo da S?lica gel, NaOH e ?gua destilada, acrescentado de pseudobohemita no gel de s?ntese. O efeito do AlMCM-41 foi satisfat?rio, pois promoveu uma diminui??o de determinadas faixas de temperatura requeridas no processo de convers?es dos hidrocarbonetos, como tamb?m promoveu uma diminui??o na energia necess?ria do processo. Possibilitando assim, menos custos relacionados ao gasto de energia para a degrada??o durante o processamento desses res?duos. Como direcionador estrutural foi utilizado CTMABr. A remo??o do direcionador org?nico (CTMABr) foi verificado por TG/DTG e FTIR, como tamb?m este material foi caracterizado por DRX, o qual foi constatado a forma??o dos principais picos caracter?sticos dos materiais mesoporosos. Pela an?lise de adsor??o/dessor??o de nitrog?nio deste material foram determinados os par?metros texturais
2

Craqueamento t?rmico e termocatal?tico do ?leo de girassol (Hellianthus annus L.) sobre materiais micro e mesoporosos / Craqueamento t?rmico e termocatal?tico do ?leo de girassol (Hellianthus annus L.) sobre materiais micro e mesoporosos

Melo, Ana Cl?udia Rodrigues de 06 December 2010 (has links)
Made available in DSpace on 2014-12-17T15:42:09Z (GMT). No. of bitstreams: 1 AnaCRM_TESE.pdf: 3734770 bytes, checksum: 59720290841ee6807d60b116e21f2090 (MD5) Previous issue date: 2010-12-06 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Microporous materials zeolite type Beta and mesoporous type MCM-41 and AlMCM-41 were synthesized hydrothermally and characterized by methods of X-ray diffraction, Fourier transform infrared, scanning electron microscopy, surface acidity, nitrogen adsorption, thermal analysis TG / DTG. Also we performed a kinetic study of sunflower oil on micro and mesoporous catalysts. The microporous material zeolite beta showed a lower crystallinity due to the existence of smaller crystals and a larger number of structural defects. As for the mesoporous materials MCM-41 and AlMCM-41 samples showed formation of hexagonal one-dimensional structure. The study of kinetic behavior of sunflower oil with zeolite beta catalysts, AlMCM-41 and MCM-41 showed a lower activation energy in front of the energy of pure sunflower oil, mainly zeolite beta. In the thermal cracking and thermocatalytic of sunflower oil were obtained two liquid fractions containing an aqueous phase and another organic - organic liquid fraction (FLO). The FLO first collected in both the thermal cracking as the thermocatalytic, showed very high level of acidity, performed characterizations of physicochemical properties of the second fraction in accordance with the specifications of the ANP. The second FLO thermocatalytic collected in cracking of sunflower oil presented results in the range of diesel oil, introducing himself as a promising alternative for use as biofuel liquid similar to diesel, either instead or mixed with it / Os materiais microporosos tipo ze?lita beta e mesoporosos tipo MCM-41 e AlMCM-41 foram sintetizados hidrotermicamente e caracterizados pelos m?todos de difra??o de raios X, infravermelho por transformada de Fourier, microscopia eletr?nica de varredura, acidez superficial, adsor??o de nitrog?nio, an?lise t?rmica via TG/DTG. Ainda foi realizado um estudo do comportamento cin?tico termogravim?trico do ?leo de girassol sobre os catalisadores micro e mesoporosos citados. Usando curvas integrais da TG e o m?todo cin?tico de Vyazovkin, foram estimados a energia de ativa??o, as taxas de convers?o e o tempo degrada??o do ?leo em fun??o da temperatura. O material microporoso ze?lita beta apresentou menor cristalinidade, devido ? exist?ncia de cristais menores e um maior n?mero de defeitos estruturais. Quanto aos materiais mesoporosos MCM-41 e AlMCM-41 apresentaram amostras com forma??o da estrutura hexagonal unidimensional. O estudo do comportamento cin?tico do ?leo de girassol com os catalisadores ze?lita beta, AlMCM-41 e MCM-41, mostrou uma menor energia de ativa??o frente a energia do ?leo de girassol puro, principalmente a ze?lita beta. No craqueamento t?rmico e termocatal?tico do ?leo de girassol foram obtidas duas fra??es l?quidas contendo uma fase aquosa e outra org?nica fra??o l?quida org?nica (FLO). A primeira FLO coletada, tanto no craqueamento t?rmico quanto no termocatal?tico, apresentou ?ndice de acidez muito elevado, sendo assim foi realizada as caracteriza??es das propriedades f?sico-qu?micas da segunda fra??o de acordo com as especifica??es da ANP. As segundas FLOs coletadas no craqueamento termocatal?tico do ?leo de girassol apresentaram resultados na faixa adequada ao diesel de petr?leo, apresentando-se como uma alternativa promissora para utiliza??o como biocombust?vel l?quido similar ao diesel, seja em substitui??o, ou misturado a este
3

S?ntese e caracteriza??o de peneiras moleculares mesoporosas do tipo MCM-41 e AlMCM-41 a partir de fontes alternativas de s?lica e de alum?nio

Silva, Marta L?gia Pereira da 01 June 2009 (has links)
Made available in DSpace on 2014-12-17T14:07:01Z (GMT). No. of bitstreams: 1 MartaLPS_partes_autorizadas_pelo autor.pdf: 1296900 bytes, checksum: ae142b4d715f0718971945acd4c853ad (MD5) Previous issue date: 2009-06-01 / Conselho Nacional de Desenvolvimento Cient?fico e Tecnol?gico / The mesoporous molecular sieves of MCM-41 and AlMCM-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 the molecular sieves MCM-41 and AlMCM-41 were synthesized by replacing the source of silica conventionally used, for quartz, an alternative and abundant, and the use of waste from the production of diatomaceous earth, an aluminum-silicate, as a source aluminum, due to abundant reserves of diatomaceous earth in the state of Rio Grande do Norte in the city of Cear?-Mirim, with the objective of producing high-value materials that have similar characteristics to traditional commercial catalysts in the market. These materials were synthesized by the method of hydrothermal synthesis at 100 ? C for 7 days and subjected to calcination at 500 ? C for 2 hours under flow of nitrogen and air. The molecular sieves were characterized by X-ray diffraction (XRD), differential thermal analysis (DTA) and thermogravimetric analysis (TG), adsorption of N2 (BET and BJH methods), spectroscopy in the infra red (FTIR), microscopy scanning electron (SEM) and transmission electron microscopy (TEM). The analysis indicated that the synthesized materials showed characteristic hexagonal structure of mesopores materials with high specific surface area and sort and narrow distribution of size of pores / As peneiras moleculares mesoporosas do tipo MCM-41 e AlMCM-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 foram sintetizadas as peneiras moleculares MCM-41 e AlMCM-41 atrav?s da substitui??o da fonte de s?lica convencionalmente utilizada, por quartzo, uma fonte alternativa e abundante, e pela utiliza??o do rejeito da produ??o de diatomita, um alumino-silicato, como fonte de alum?nio, devido a abundante reserva de diatomita no estado do Rio Grande do Norte, no munic?pio de Cear?-Mirim, com o objetivo de produzir materiais de alto valor agregado que apresentam caracter?sticas semelhantes aos catalisadores comerciais tradicionalmente existentes no mercado. Estes materiais foram sintetizados pelo m?todo de s?ntese hidrot?rmica a 100 ?C por 7 dias, e submetidos a calcina??o a 500 ?C por 2 horas sob fluxo de nitrog?nio e ar. As peneiras moleculares foram caracterizadas por difra??o de raios-X (DRX), an?lises t?rmicas diferencial (DTA) e termogravim?trica (TG), fisissor??o de N2, (M?todos de BET e BJH), espectroscopia na regi?o do infra vermelho (FTIR), microscopia eletr?nica de varredura (MEV) e microscopia eletr?nica de transmiss?o (MET). As an?lises indicaram que os materiais sintetizados apresentaram estrutura hexagonal caracter?stica dos materiais mesoporosos, com elevadas ordena??o e ?rea superficial espec?fica e estreita distribui??o de tamanho de poros

Page generated in 0.0214 seconds