Amphiphilic chemical additives are widely used to prevent the formation of asphaltene deposits and to promote demulsification of crude oil. Although it is known that the efficiency of these additives is mainly related to their structure and molar mass, this correlation is still not well established, because it is also related to the type of petroleum to be treated. In this work, C10I asphaltenes extracted from two different types of asphaltic residues were used to prepare model systems containing 1 wt % asphaltenes in toluene. Amphiphilic macromolecules, obtained from polymerization of cardanol by polyaddition and polycondensation, were characterized by Fourier transform infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR), and size-exclusion chromatography (SEC) and evaluated regarding their influence on the variation of asphaltene precipitation onset of model systems and the variation of volume and separation kinetics of water in model water-in-oil emulsions. The results show that the structure of polycardanol obtained by polyaddition favors its action as a dispersant of asphaltenes, which can be related to the fact that its phenol groups are relatively free to interact with the sites of the asphaltene molecules, as opposed to polymers obtained by polycondensation, in which the polymerization reaction occurs in the aromatic ring. Besides this, the demulsification results indicate a close relation of the dispersant action of this type of additive with its performance in water–toluene separation, so that the separation kinetics is mainly related to the molar mass of the additive in determining the final performance. The results highlight potential asphaltene dispersants derived from renewable sources.

Recebido em 13/4/12; aceito em 2/7/12; publicado na web em 21/9/12The structure of the various asphaltenic subfractions found in crude oil was evaluated. For this purpose, C5 asphaltenes were extracted from an asphaltic residue using n-pentane as the flocculant solvent. The different subfractions were isolated from the C5 asphaltenes by the difference in solubility in different solvents. These were characterized by infrared spectroscopy, nuclear magnetic resonance, X-ray fluorescence, elementary analysis and mass spectrometry. The results confirmed that the subfractions extracted with higher alkanes had greater aromaticity and molar mass. However, small solubility variations between the subfractions were attributed mainly to the variation in the concentrations of cyclical hydrocarbon compounds and metals.

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The production of heavy oil has emerged as one of the great challenges of the oil industry today. The high viscosity, characteristic of these oils is linked to factors such as the presence of higher molecular weight components, asphaltenes, paraffins, resins and even due to emulsion stability. Highly emulsified oils are seen as a big problem because it directly affects the oil production and the costs involved to do it. Already the phase behavior of asphaltenes has been the subject of discussion in various jobs that match to recognize its complexity. Thus it is of utmost importance to develop new technologies that act reducing the viscosity and consequently reflecting in higher yields with lower costs. This study aimed to develop products that act reducing the viscosity, in operations where asphaltene dispersion and controlled droplet size of emulsified water from the system increased, so as to promote a significant reduction in viscosity with the use of environmentally products correct. A sample of oil used in the tests was from an exploratory field onshore Colombia. Products containing mixtures of different green chemical-polymeric agents with the intention of promoting a multifunctional and excellent synergy with the proposed system were developed. The analyzes were performed oil viscosity in a Haake RS 600, wherein the oil had its SARA and its water content measured by Karl Fischer. The results obtained with viscosity reduction were highly significant and promising, as the oil used in this study, no previous treatment had a viscosity of approximately 180000 cP, and after the development and application of the product is reached viscosities of up to 25 cP, while optimizing the process of demulsification end of oil.