Asphaltenes
Mostrando 1-12 de 34 artigos, teses e dissertações.
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1. Influence of Refinery Asphalt Residue Addition on Flow: A Study Using Waxy Model-System
One of the main phenomena causing problems in the oil industry is the precipitation of waxes, which can crystallize and form deposits, clogging lines and reducing flows. Many studies have been conducted seeking to overcome this problem, mainly through application of chemical to increase flow. Some studies have shown that the asphaltenes present in crude oil
Journal of the Brazilian Chemical Society. Publicado em: 2023
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2. EVALUATION OF THE CHEMICAL COMPOSITION AND STRUCTURE OF ASPHALTENES FROM THREE OFFSHORE BRAZILIAN BIODEGRADED HEAVY OILS
Asphaltenes fractions were extracted and purified from three heavy Brazilian oils. Their mass compositions of C, H, N, Ni and V were obtained from elemental analysis and S and O atomic percentages from EDS. The H/C ratios showed high degree of unsaturation, while the O atomic percentages indicated more pronounced biodegradation effects on two samples. Quanti
Quím. Nova. Publicado em: 2021-04
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3. The Stabilization of Asphaltenes in Different Crude Fractions: A Molecular Approach
The conditions of petroleum extraction may allow asphaltenes to precipitate, causing deposition that clogs wells, pipes and equipment, consequently reducing productivity. In this work, the solubility parameters and precipitation onset of polar fractions of heavy crudes from Brazilian fields were estimated using a simplified system of n-heptane/toluene mixtur
J. Braz. Chem. Soc.. Publicado em: 2021-04
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4. Recent Developments on the Elucidation of Colloidal Aspects of Asphaltenes and Their Relevance to Oilfield Problems
Asphaltenes constitute the heavy petroleum fraction responsible for deposition events that may lead to reduced oil production, therefore of great interest for flow assurance. These molecules self-assemble in solutions leading to formation of aggregates that eventually grow towards precipitation and blockages in reservoirs and pipelines. Based on the Yen-Mull
J. Braz. Chem. Soc.. Publicado em: 2020-02
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5. THERMODYNAMIC ANALYSIS AND MODELING OF BRAZILIAN CRUDE OIL AND ASPHALTENE SYSTEMS: AN EXPERIMENTAL MEASUREMENT AND A PC-SAFT APPLICATION
ABSTRACT Asphaltenes represent the heaviest fraction of crude oils, being recognized by their tendency to self-associate and precipitate. Asphaltene precipitation and subsequent deposition can cause problems in all stages of production. The objective of this paper is to model Brazilian crude oil and asphaltene systems using the PC-SAFT equation of state. Asp
Braz. J. Chem. Eng.. Publicado em: 15/07/2019
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6. Automatized Separation of Fractions from Petroleum Based on Spectrophotometric Signal Derivative Using Open-Source Hardware for the Determination of Ni and V Linked to Porphyrins
An automated method based on open-source hardware was created for the separation of porphyrins fractions from crude oil, an essential step for the quantification of V and Ni as metalloporphyrins. Preparative liquid chromatography was implemented with a reverse phase gradient from MeOH to toluene. The system allows three solvents and fractions changes by usin
J. Braz. Chem. Soc.. Publicado em: 23/05/2019
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7. Optimal hydrated lime concentration in asphalt binder to improve photo degradation resistance
Abstract The effect of short-term oxidation, evaluated by using a Rolling Thin Film Oven Test, and the effect of weathering aging on the oxidation process of hydrated lime modified asphalts were studied. Hydrated lime (HL) has been known as an additive for asphalt mixtures and is now considered as a binder additive that increases asphalt mixture durability.
REM, Int. Eng. J.. Publicado em: 2018-04
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8. CORRELAÇÕES GEOQUÍMICAS ENTRE AMOSTRAS DE PETRÓLEO DA BACIA POTIGUAR E DEFINIÇÃO DE SUAS POSSÍVEIS ROCHAS GERADORAS
Eight petroleum samples from Potiguar Basin were submitted for determination of saturated biomarkers by gas chromatography (fingerprint), liquid chromatography (saturates, aromatics, resins and asphaltenes), gas chromatography-mass spectrometry (GC-MS), nickel and vanadium by high resolution continuum source graphite furnace atomic absorption spectrometry (H
Quím. Nova. Publicado em: 2018-04
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9. AVALIAÇÃO DE ASFALTENOS PRECIPITADOS EM DIFERENTES CONDIÇÕES DE COMPOSIÇÃO, TEMPERATURA E PRESSÃO
Asphaltenes are a heavy fraction of petroleum with the ability for self-association, a phenomenon that can occur spontaneously in the reservoirs or in any of the various stages of production and processing, depending on variations in pressure, temperature, composition and shearing, among others. In this work, it was evaluated the precipitation of asphaltenes
Quím. Nova. Publicado em: 2018-02
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10. COMPARISON BETWEEN ASPHALTENES (SUB)FRACTIONS EXTRACTED FROM TWO DIFFERENT ASPHALTIC RESIDUES: CHEMICAL CHARACTERIZATION AND PHASE BEHAVIOR
Asphaltenes are blamed for various problems in the petroleum industry, especially formation of solid deposits and stabilization of water-in-oil emulsions. Many studies have been conducted to characterize chemical structures of asphaltenes and assess their phase behavior in crude oil or in model-systems of asphaltenes extracted from oil or asphaltic residues
Quím. Nova. Publicado em: 2016-01
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11. Chemical modification of cobalt ferrite nanoparticles with possible application as asphaltene flocculant agent
Asphaltenes can cause enormous losses in the oil industry, because they are soluble only in aromatic solvents. Therefore, they must be removed from the petroleum before it is refined, using flocculant agents. Aiming to find new materials that can work as flocculant agents to asphaltenes, cobalt ferrite nanoparticles were chemically modified through acid-base
Mat. Res.. Publicado em: 02/04/2013
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12. The influence of asphaltenes subfractions on the stability of crude oil model emulsions
O petróleo é produzido na forma de emulsão água em óleo e os asfaltenos são considerados os principais responsáveis pela estabilização dessas emulsões. O objetivo deste trabalho foi avaliar a influência de diferentes frações asfaltênicas sobre a estabilidade de emulsões modelo de petróleo (salmoura em asfaltenos/tolueno) e sobre a eficiência
J. Braz. Chem. Soc.. Publicado em: 28/01/2013