A5084444102- Petroleum Processing and Analysis
- Hydrocarbon exploration and reservoir analysis
- Enhanced Oil Recovery Techniques
- Phase Equilibria and Thermodynamics
- Mass Spectrometry Techniques and Applications
- Surfactants and Colloidal Systems
- Photochemistry and Electron Transfer Studies
- Chemical Reaction Mechanisms
- Free Radicals and Antioxidants
- Crystallization and Solubility Studies
- Analytical Chemistry and Chromatography
- Porphyrin and Phthalocyanine Chemistry
- Chemical Reactions and Mechanisms
- Reservoir Engineering and Simulation Methods
- Catalysis and Hydrodesulfurization Studies
- Heat transfer and supercritical fluids
- Spectroscopy and Quantum Chemical Studies
- Infrastructure Maintenance and Monitoring
- Cultural Heritage Materials Analysis
- Asymmetric Synthesis and Catalysis
- Catalysis and Oxidation Reactions
- Hydraulic Fracturing and Reservoir Analysis
- Synthesis and Characterization of Heterocyclic Compounds
- Pesticide Residue Analysis and Safety
- Oil, Gas, and Environmental Issues
Central University of Venezuela
2014-2024
Sociedade Brasileira de Química
2016
Centre National de la Recherche Scientifique
2009
Université de Pau et des Pays de l'Adour
2009
Ollscoil na Gaillimhe – University of Galway
2007
Petroleum of Venezuela (Venezuela)
2001-2002
University of Essex
1987
The precipitation and deposition of asphaltenes is a primary problem related to the processing, transportation, production oil. Flocculation asphaltene aggregates likely occur during processing crude Recently, it has been shown that nanotechnology in form nanoparticles useful for inhibition or prevention formation damage. Although well-known adsorption on nanoparticle surface would reduce capacity these asphaltic compounds interact with each other, limited studies have performed regarding...
The main objective of this study is to investigate the effect resin I on adsorption behavior n-C7 asphaltenes onto silica and hematite nanoparticles. It worthwhile mention, for first time, that competitive asphaltene over nanoparticles reported. Indeed, a novel method based thermogravimetric analysis (TGA) softening point (SP) measurements was used simultaneously construction isotherms resins. experiments were conducted in batch mode at different (A:R) ratios 7:3, 1:1, 3:7 concentrations...
Seven asphaltene samples and six octylated (OA) derivatives were analyzed using laser desorption ionization−time-of-flight (LDI−TOF) mass spectrometry (abbreviated as MS) vapor pressure osmometry (VPO) techniques. Molecular weight distributions (MWDs) that determined MS spanned, for all asphaltenes their counterparts, a similar range, from ∼100 Da to ∼10 000 Da. For asphaltenes, the number-average molecular (Mn) weight-average (Mw) afforded values in 1900 ± 200 3200 400 intervals,...
The proposition of the hypothesis-relating structure with properties asphaltenes is a very important endeavor. In view their complexity, being an intricate mixture high-molecular-mass compounds, experimental and theoretical procedures must be designed to check whether structures proposed are consistent expected found behavior. During recent years, structural characteristic asphaltene, whereby several polycyclic systems present in them joined by flexible aliphatic chains, has been authors....
The Sphere method developed by Hansen (Hansen, C. M. Solubility Parameters: A User's Handbook; CRC Press: Boca Raton, FL, 1999) to calculate components of solubility parameters (SP), δD, δP, and δH, where D, P, H stand for dispersion, polar, hydrogen bonding respectively, have been applied resins, asphaltenes, fractions A1 A2. Mean values these compounds in MPa0.5 were asphaltenes (19.5 ± 0.1, 4.7 0.2, 4.2 0.1); A2 (19.6 5.8 4.4 0.2); (20.9 5.6 0.3, 6.8 resins (18.6 3.6 3.2 0.3). Also, the...
The aggregation behavior of model molecules asphaltene subfractions A1 and A2 dissolved in heptane, toluene, tetrahydrofuran (THF) were studied using molecular dynamics simulations. proposed models are based on previously structures with two new models, including a highly aromatic prominent island-type molecule another archipelago-type architecture. mechanisms THF, heptane solvents studied. results toluene consistent the solubility asphaltenes their these solvents. size aggregates is...
Adsorption isotherms of two native resins on different asphaltene surfaces were obtained using the UV spectrophotometric technique. The shape curves can be attributed both to multilayer adsorption and penetration in microporous structure asphaltenes. relationship between behavior activity as stabilizers indicates that their effectiveness is related adsorbed amount particles also capacity dissolve results support a model for stabilization where are incorporated into bulk asphaltenes helping...
Cumene solutions of asphaltenes (8 g/L) were treated with p-nitrophenol (PNP) and a precipitated solid was collected after 3 days. For the asphaltene samples examined, between 48 70% sample could be by this treatment. PNP, known to form charge-transfer complexes aromatic compounds, probably forms type compounds asphaltenes, leading precipitation. The dissolved in chloroform, PNP removed extraction aqueous sodium hydroxide. Although initial has usual high solubility toluene (higher than 50...
ABSTRACT The distribution of egg and larvae mackerel, horse sardine, hake, megrim, blue whiting anchovy along the European Atlantic waters (south Portugal to Scotland) during 1998 is described. Time year, sea surface temperature bottom depth are used define spawning habitat different species. Mackerel, sardine eggs presented widest distribution, whereas megrim showed a limited restricted Celtic Sea Bay Biscay respectively. Correspondingly mackerel highest aggregation indices. Blue were found...
A combined liquid chromatography coupled to a mass spectrometer with an ICP detector (μSEC-HR MS; μSEC for brevity) technique was used analyze the metals in four asphaltenes and their corresponding A1 (toluene insoluble), A2 soluble), trapped compound (TC, heptane soluble) fractions. For three of asphaltene samples, normalized profiles both nickel sulfur were very similar, showing that porphyrins distributed almost all types aggregates. Extensive overlapping observed vanadium at retention...
Adsorption of asphaltenes on glass surface has been studied by using photothermal deformation spectroscopy. This technique was adapted for direct measurement the amount asphaltene adsorbed plate surfaces. Solid-solution adsorption isotherms were obtained at room temperature in toluene. Stepwise or multilayer detected three cases examined (Furrial, Jobo, and Hamaca) after long contact periods. After first layer due to saturation one (Jobo two (Furrial) further layers measured. Analysis...
Amphiphiles are frequently used to prevent asphaltene precipitation in reservoir rocks and wellbore tubing. It is supposed that these substances can stabilize the asphaltenes forming a steric stabilization layer around them. In this study, adsorption isotherms of two amphiphiles (nonylphenol nonylphenolic resin) native resin on particles obtained order analyze relationship between effectiveness compounds as stabilizers. The comparison three reveals significant difference behavior fraction...
The adsorption kinetics of asphaltenes at the toluene − silica interface has been measured for nine solution concentrations CS (from 5 to 3000 mgL-1) Results could be adjusted an irreversible second-order kinetics, where rate k was strongly dependent on concentration. Thus a large reduction in observed when increased studied concentration range. This accounted terms aggregates formed solution. step wise trends isotherms mineral surfaces, reproduced using above values.
Trapping of compounds by asphaltenes in guest−host complexes (GHC) is an important phenomenon relevant to many properties the system, such as asphaltene structure, swelling and solvent trapping, geochemical impact, well trapping metalloporphyrins, free radicals, resins, other crude oil components, as, e.g., paraffin. Several mechanisms, adsorption occlusion, during separation from can be considered, but most interest attracted GHC, which guest firmly bound cannot completely liberated host...
Effects of pressure on thermo-oxidative decomposition different sources n-C7 asphaltenes were investigated at high using a thermogravimetric analyzer under an air atmosphere. The extracted from heavy and extra-heavy crude oils around the world thoroughly characterized by elemental analysis (EA), vapor osmometry (VPO), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FTIR) spectroscopy, diffraction (XRD), nuclear magnetic resonance (NMR) techniques. A high-pressure coupled...
Two acidic samples, A and B, were isolated from Cerro Negro extraheavy crude oil. Sample has a relatively low number average molecular weight (Mn = 480 Da), aromaticity (fa 15.2%), γ (6.8 m Nm-1, toluene−0.1 N HCl), whereas for these values Mn 1200 Da, fa 20%, 14.8 Nm-1. These could be compared to those asphaltenes under the same conditions 5000, in toluene by VPO, 47%, 20.9 Nm-1).
A sample of asphaltenes (ACN) precipitated from Cerro Negro crude oil had been divided into 14 fractions using a dialysis procedure employing THF−acetone mixtures as the extracting solvent. Seven extracts (F1−F7) and corresponding residues R1−R7 were obtained mixture composition changed 40 to 100% THF. These materials characterized by elemental analyses, VPO, solubility, C-13 NMR, electron paramagnetic resonance (EPR). As last are aproached, following trends observed: H/C decreases,...