Made available in DSpace on 2016-08-19T12:56:42Z (GMT). No. of bitstreams: 1 Dissertacao Irata.pdf: 3144382 bytes, checksum: c6e6615b3bf42aec9baa1245f95165df (MD5) Previous issue date: 2013-10-04 / The oil´s behavior s study, mainly the hard fractions, including asphaltenes and resins, have became extremely important, since the relations between theses constituents during the oil mixing operations and its derivatives may bring several problems with the asphaltenes precipitance. Undesirable, the precipitance may cause pipe s obstruction during the oil s extraction, slowing down the production and rising up the expenses. These facts have motivated this work, that seek determine the influence of temperature and adding particulate materials, in the beginning of asphaltenes precipitation (IP) in models solutions, intending in better characterize the precipitation process, once many of the models applied to determinate the stability and compatibility between these oils, for example, are based on data from the beginning of the precipitation (IP). The technique spectroscopy near Infrared was used to determine the precipitation of asphaltenes in the temperature range from 10 to 30 ºC and with different particle materials (calcareous, sandstone, clay) and a optical microscopy technique determining IP with no temperature variations, contributing as basis for the obtained value, using the NIR technique. The results will designate the temperature variation, with little influences on precipitation, according to the literature. Particle adding (calcareous and clay) have proved to be significant, modifying significantly the asphaltenes precipitation outset, however, the same thing hasn t been noticed with the sandstone particles. / O estudo do comportamento do petróleo, principalmente das frações pesadas, que incluem asfaltenos e resinas, tem se tornado extremamente importante, visto que as relações entre esses constituintes durante as operações de misturas de petróleos e de petróleos e seus derivados, podem trazer inúmeros problemas com a precipitação dos asfaltenos. Indesejável, a precipitação pode ocasionar obstruções de tubulações durante a extração do petróleo, diminuindo a produtividade e aumentando os custos, o que motivou a realização deste trabalho que objetiva determinar a influência da temperatura e da adição de materiais particulados, no início de precipitação (IP) dos asfaltenos em soluções modelos, no intuito de melhor caracterizar o processo de precipitação, uma vez que muitos dos modelos empregados para determinar a estabilidade e a compatibilidade entre petróleos, por exemplo, baseiam-se nos dados do início de precipitação. A técnica de Infravermelho Próximo (NIR) foi utilizada para determinar o início de precipitação (IP) dos asfaltenos na faixa de temperatura de 10 a 30ºC e com diferentes materiais particulados (calcário, arenito e argila) e a técnica de microscopia óptica na determinação do IP servindo como base para os valores obtidos com uso da técnica NIR. Os resultados indicaram variações de temperatura, pouco influentes na precipitação, em acordo com a literatura. As adições de particulados (calcário e argila) mostraram-se significativas, alterando relevantemente o início de precipitação dos asfaltenos, no entanto, o mesmo não foi observado para os particulados de arenito.

Particles and macromolecular components, including biopolymers (protein and carbohydrate), are viewed as the main foulants in the complex feed submerged membrane filtration systems such as membrane bioreactor (MBR). This work focused on two aspects of fouling in complex fluids: 1- Assessing fouling propensity and mechanisms for various model solutions. 2- Using of two specific solutions modelling biomass found in MBR for a better understanding of the fouling mechanisms in submerged MBR processes. Filtrations were carried out with 0.22 ??m PVDF hollow fibre membrane. Alginate was used as a model for polysaccharide, bovine serum albumin (BSA) as a model for protein, (un)washed yeast and bentonite were representing suspended solid contents. According to the data obtained during this study the fouling propensity of each model solution was classified as follow in a decreasing order: Alginate &gt unwashed yeast &gt washed yeast &gt BSA &gt bentonite for one-component solutions; and Alginate-washed yeast &gt Alginate-BSA &gt Alginate-bentonite &gt Alginate-unwashed yeast for two-component solutions. Introducing the alginate increased the reversible fouling (except BSA). Passive adsorption had a significant effect on fouling of alginate even before the beginning of the filtration. Washed yeast and a mixture of washed yeast + BSA were then used as model solutions to simulate the activated sludge found in MBR. The concentration of washed yeast and BSA used in this study were calculated in order for the characterisations of the two model solution to match (in terms of biopolymer contents) those of MBR biomasses reported in the literature. By rinsing, backwashing and chemical cleaning of the membrane, three fouling layers of upper, intermediate and lower were defined respectively. Results obtained from the analysis of the biopolymers found in the cleaning solutions allow a better understanding of the fouling mechanisms occurring for the two model solutions used in this study: for washed yeast, the lower layer and for washed yeast + BSA , the upper and intermediate layers were found to have relatively high biopolymeric composition. This was explained by higher concentration of solids on the membrane surface and by higher biopolymer interactions when washed yeast was mixed with BSA.

Particles and macromolecular components, including biopolymers (protein and carbohydrate), are viewed as the main foulants in the complex feed submerged membrane filtration systems such as membrane bioreactor (MBR). This work focused on two aspects of fouling in complex fluids: 1- Assessing fouling propensity and mechanisms for various model solutions. 2- Using of two specific solutions modelling biomass found in MBR for a better understanding of the fouling mechanisms in submerged MBR processes. Filtrations were carried out with 0.22 ??m PVDF hollow fibre membrane. Alginate was used as a model for polysaccharide, bovine serum albumin (BSA) as a model for protein, (un)washed yeast and bentonite were representing suspended solid contents. According to the data obtained during this study the fouling propensity of each model solution was classified as follow in a decreasing order: Alginate &gt unwashed yeast &gt washed yeast &gt BSA &gt bentonite for one-component solutions; and Alginate-washed yeast &gt Alginate-BSA &gt Alginate-bentonite &gt Alginate-unwashed yeast for two-component solutions. Introducing the alginate increased the reversible fouling (except BSA). Passive adsorption had a significant effect on fouling of alginate even before the beginning of the filtration. Washed yeast and a mixture of washed yeast + BSA were then used as model solutions to simulate the activated sludge found in MBR. The concentration of washed yeast and BSA used in this study were calculated in order for the characterisations of the two model solution to match (in terms of biopolymer contents) those of MBR biomasses reported in the literature. By rinsing, backwashing and chemical cleaning of the membrane, three fouling layers of upper, intermediate and lower were defined respectively. Results obtained from the analysis of the biopolymers found in the cleaning solutions allow a better understanding of the fouling mechanisms occurring for the two model solutions used in this study: for washed yeast, the lower layer and for washed yeast + BSA , the upper and intermediate layers were found to have relatively high biopolymeric composition. This was explained by higher concentration of solids on the membrane surface and by higher biopolymer interactions when washed yeast was mixed with BSA.