Sample records for automated on-column asphaltene

  1. Heavy Oil Process Monitor: Automated On-Column Asphaltene Precipitation and Re-Dissolution

    John F. Schabron; Joseph F. Rovani; Mark Sanderson


    An automated separation technique was developed that provides a new approach to measuring the distribution profiles of the most polar, or asphaltenic components of an oil, using a continuous flow system to precipitate and re-dissolve asphaltenes from the oil. Methods of analysis based on this new technique were explored. One method based on the new technique involves precipitation of a portion of residua sample in heptane on a polytetrafluoroethylene-packed (PTFE) column. The precipitated material is re-dissolved in three steps using solvents of increasing polarity: cyclohexane, toluene, and methylene chloride. The amount of asphaltenes that dissolve in cyclohexane is a useful diagnostic of the thermal history of oil, and its proximity to coke formation. For example, about 40 % (w/w) of the heptane asphaltenes from unpyrolyzed residua dissolves in cyclohexane. As pyrolysis progresses, this number decrease to below 15% as coke and toluene insoluble pre-coke materials appear. Currently, the procedure for the isolation of heptane asphaltenes and the determination of the amount of asphaltenes soluble in cyclohexane spans three days. The automated procedure takes one hour. Another method uses a single solvent, methylene chloride, to re-dissolve the material that precipitates on heptane on the PTFE-packed column. The area of this second peak can be used to calculate a value which correlates with gravimetric asphaltene content. Currently the gravimetric procedure to determine asphaltenes takes about 24 hours. The automated procedure takes 30 minutes. Results for four series of original and pyrolyzed residua were compared with data from the gravimetric methods. Methods based on the new on-column precipitation and re-dissolution technique provide significantly more detail about the polar constituent's oils than the gravimetric determination of asphaltenes.


    John F. Schabron; Joseph F. Rovani Jr; Mark Sanderson


    About 37-50% (w/w) of the heptane asphaltenes from unpyrolyzed residua dissolve in cyclohexane. As pyrolysis progresses, this number decrease to below 15% as coke and toluene insoluble pre-coke materials appear. This solubility measurement can be used after coke begins to form, unlike the flocculation titration, which cannot be applied to multi-phase systems. Currently, the procedure for the isolation of heptane asphaltenes and the determination of the amount of asphaltenes soluble in cyclohexane spans three days. A more rapid method to measure asphaltene solubility was explored using a novel on-column asphaltene precipitation and re-dissolution technique. This was automated using high performance liquid chromatography (HPLC) equipment with a step gradient sequence using the solvents: heptane, cyclohexane, toluene:methanol (98:2). Results for four series of original and pyrolyzed residua were compared with data from the gravimetric method. The measurement time was reduced from three days to forty minutes. The separation was expanded further with the use of four solvents: heptane, cyclohexane, toluene, and cyclohexanone or methylene chloride. This provides a fourth peak which represents the most polar components, in the oil.

  3. Determination of asphaltenes in heavy oils using an on-column method

    Rogel, E.; Ovalles, C.; Moir, M. [Chevron Energy Technology Co., Richmond, CA (United States); Schabron, J.F. [Western Research Inst., Laramie, WY (United States)


    An improved analytical method for determining the asphaltene content in crude oil and petroleum samples was presented. The method used an on-column precipitation technique coupled with an evaporative light scattering detector (ELSD). The column has an inert packing material where the asphaltene was precipitated and re-dissolved using a solvent. Heavy crude oils with asphaltene contents ranging from 5 to 25 per cent w/w were tested. A blend of 90:10 dichloromethane and methanol was used to decrease the influence of hydrocarbon adsorption mechanisms from the polymeric liquid chromatographic phases. A series of laboratory experiments were conducted to compare results obtained using the method with results obtained using traditional gravimetric methods. Regression analysis was used to determine the calibration constants. The study showed that the method can be used as replacement for conventional gravimetric methods when faster results are needed or when sample sizes are small. It was concluded that the method was able to accurately quantify asphaltene contents as low as 120 ppm. 8 refs., 1 tab., 3 figs.

  4. The Asphaltenes

    Mullins, Oliver C.


    Asphaltenes, the most aromatic of the heaviest components of crude oil, are critical to all aspects of petroleum utilization, including reservoir characterization, production, transportation, refining, upgrading, paving, and coating materials. The asphaltenes, which are solid, have or impart crucial and often deleterious attributes in fluids such as high viscosity, emulsion stability, low distillate yields, and inopportune phase separation. Nevertheless, fundamental uncertainties had precluded a first-principles approach to asphaltenes until now. Recently, asphaltene science has undergone a renaissance; many basic molecular and nanocolloidal properties have been resolved and codified in the modified Yen model (also known as the Yen-Mullins model), thereby enabling predictive asphaltene science. Advances in analytical chemistry, especially mass spectrometry, enable the identification of tens of thousands of distinct chemical species in crude oils and asphaltenes. These and other powerful advances in asphaltene science fall under the banner of petroleomics, which incorporates predictive petroleum science and provides a framework for future developments.

  5. Interfacial behavior of asphaltenes.

    Langevin, Dominique; Argillier, Jean-François


    We review the existing literature on asphaltenes at various types of interfaces: oil-water, air-water, gas-oil and solid-liquid, with more emphasis on the oil-water interfaces. We address the role of asphaltene aggregation, recently clarified for asphaltenes in bulk by the Yen-Mullins model. We discuss the questions of adsorption reversibility and interfacial rheology, especially in connection with emulsion stability. PMID:26498501

  6. The fractal aggregation of asphaltenes.

    Hoepfner, Michael P; Fávero, Cláudio Vilas Bôas; Haji-Akbari, Nasim; Fogler, H Scott


    This paper discusses time-resolved small-angle neutron scattering results that were used to investigate asphaltene structure and stability with and without a precipitant added in both crude oil and model oil. A novel approach was used to isolate the scattering from asphaltenes that are insoluble and in the process of aggregating from those that are soluble. It was found that both soluble and insoluble asphaltenes form fractal clusters in crude oil and the fractal dimension of the insoluble asphaltene clusters is higher than that of the soluble clusters. Adding heptane also increases the size of soluble asphaltene clusters without modifying the fractal dimension. Understanding the process of insoluble asphaltenes forming fractals with higher fractal dimensions will potentially reveal the microscopic asphaltene destabilization mechanism (i.e., how a precipitant modifies asphaltene-asphaltene interactions). It was concluded that because of the polydisperse nature of asphaltenes, no well-defined asphaltene phase stability envelope exists and small amounts of asphaltenes precipitated even at dilute precipitant concentrations. Asphaltenes that are stable in a crude oil-precipitant mixture are dispersed on the nanometer length scale. An asphaltene precipitation mechanism is proposed that is consistent with the experimental findings. Additionally, it was found that the heptane-insoluble asphaltene fraction is the dominant source of small-angle scattering in crude oil and the previously unobtainable asphaltene solubility at low heptane concentrations was measured. PMID:23808932

  7. Athabasca asphaltene structures

    Dettman, H.; Salmon, S.; Zinz, D. [National Centre for Upgrading Technology, Devon, AB (Canada)


    In order to model petroleum behaviour during production and refining processes, it is important to understand the molecular character of oil components. Gas chromatography can be used to separate components with boiling points less than 524 degrees C. However, since asphaltenes have a higher boiling point, gel permeation chromatography (GPC) must be used to separate species before analysis. Analysis of Athabasca asphaltene GPC fractions has shown that asphaltenes consist of 2 types of species, notably crunchy species that are graphitic in appearance, and oily species. The molecular weights range from 400 to 2000 g/mole as measured by low resolution mass spectrometry. This poster described the ongoing effort to separate the asphaltenes by polarity. Athabasca asphaltenes were subfractioned into 4 parts according to differential solubility in pentane and centrifugation. Acidic species were isolated from the asphaltenes using adsorption chromatography. The 4 polarity fractions and acid species have been characterized with particular reference to elemental and metals content. Analyses were performed by Fourier transform infrared (FTIR) and nuclear magnetic resonance (NMR) carbon type analyses. This poster provided comparisons of their elution profiles by GPC. tabs., figs.

  8. Raman spectrum of asphaltene

    Abdallah, Wael A.


    Asphaltenes extracted from seven different crude oils representing different geological formations from around the globe were analyzed using the Raman spectroscopic technique. Each spectrum is fitted with four main peaks using the Gaussian function. On the basis of D1 and G bands of the Raman spectrum, asphaltene indicated an ordered structure with the presence of boundary defected edges. The average aromatic sheet size of the asphaltene molecules is estimated within the range of 1.52-1.88 nm, which represents approximately seven to eight aromatic fused rings. This estimation is based on the integrated intensity of D1 and G bands, as proposed by Tunistra and Koenig. The results here are in perfect agreement with so many other used techniques and indicate the potential applicability of Raman measurements to determine the average aromatic ring size and its boundary. © 2012 American Chemical Society.

  9. Polymeric stabilization of colloidal asphaltenes

    Hashmi, Sara; Firoozabadi, Abbas


    Asphaltenes, the heaviest component of crude oil, cause many problems in petroleum extraction and recovery. Operationally defined as insoluble in long chain alkanes but soluble in toluene, asphaltenes have been described by bulk thermodynamic models such as the Flory-Huggins theory. However, bulk models work well only for asphaltenes in good solvents. Characterization of asphaltenes in poor solvents remains elusive: molecular scale asphaltenes readily aggregate to the colloidal scale and become highly unstable in solution. We investigate the ability of polymers to stabilize colloidal asphaltene suspensions in heptane. In the absence of added polymer, sedimentation measurements reveal dynamics reminiscent of collapsing gels. Adding polymers to colloidal asphaltene suspensions can delay the characteristic sedimentation time by orders of magnitude. Light scattering results suggest that the mechanism of stabilization may be related to a decrease in both particle size and polydispersity as a function of added polymer.

  10. A simple on-column preparation of [11C]choline. Automation and adaptation to routine production for clinical positron emission tomography (PET)

    [11C]Choline is currently a potential PET radiopharmaceutical for tumor imaging. For its routine PET application we have developed an automated synthesis system based on the Sep-Pak [11C]methylation method. A simple and highly sensitive method for the detection of residual 2-dimethylaminoethanol (DMAE) in [11C]choline injections was also developed by the combination of headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry (GC-MS). Using this system, [11C]choline ready for injection can be obtained in a decay corrected radiochemical yield of 88% with a radiochemical purity of >99% after optimizing reaction parameters. The total synthesis time was 16 min after the end of irradiation. The simplicity, the high efficiency, and the use of disposable components are advantageous for routine clinical use. (author)

  11. Asphaltene based photovoltaic devices

    Chianelli, Russell R.; Castillo, Karina; Gupta, Vipin; Qudah, Ali M.; Torres, Brenda; Abujnah, Rajib E.


    Photovoltaic devices and methods of making the same, are disclosed herein. The cell comprises a photovoltaic device that comprises a first electrically conductive layer comprising a photo-sensitized electrode; at least one photoelectrochemical layer comprising metal-oxide particles, an electrolyte solution comprising at least one asphaltene fraction, wherein the metal-oxide particles are optionally dispersed in a surfactant; and a second electrically conductive layer comprising a counter-electrode, wherein the second electrically conductive layer comprises one or more conductive elements comprising carbon, graphite, soot, carbon allotropes or any combinations thereof.

  12. Asphaltene Aggregation and Fouling Behavior

    Derakhshesh, Marzie

    This thesis explored the properties of asphaltene nano-aggregates in crude oil and toluene based solutions and fouling at process furnace temperatures, and the links between these two phenomena. The link between stability of asphaltenes at ambient conditions and fouling at the conditions of a delayed coker furnace, at over 450 °C, was examined by blending crude oil with an aliphatic diluent in different ratios. The stability of the blends were measured using a S-value analyzer, then fouling rates were measured on electrically heated stainless steel 316 wires in an autoclave reactor. The less stable the blend, the greater the rate and extent of fouling. The most severe fouling occurred with the unstable asphaltenes. SEM imaging of the foulant illustrates very different textures, with the structure becoming more porous with lower stability. Under cross-polarized light, the coke shows the presence of mesophase in the foulant layer. These data suggest a correlation between the fouling rate at high temperature furnace conditions and the stability index of the crude oil. Three organic polysulfides were introduced to the crude oil to examine their effect on fouling. The polysulfides are able to reduce coking and carbon monoxide generation in steam crackers. The fouling results demonstrated that polysulfide with more sulfur content increased the amount of corrosion-fouling of the wire. Various additives, solvents, ultrasound, and heat were employed to attempt to completely disaggregate the asphaltene nano-aggregates in solution at room temperature. The primary analytical technique used to monitor the nano-aggregation state of the asphaltenes in solution was the UV-visible spectroscopy. The results indicate that stronger solvents, such as pyridine and quinoline, combined with ionic liquids yield a slight reduction in the apparent absorbance at longer wavelengths, indicative of a decrease in the nano-aggregate size although the magnitude of the decrease is not significant

  13. Electrodeposition of Asphaltenes. 2. Effect of Resins and Additives

    Khvostichenko, Daria S; Andersen, Simon Ivar


    Electrodeposition of asphaltenes from oil/heptane, asphaltene/heptane, and asphaltene/heptane/additive mixtures has been investigated. Toluene, native petroleum resins, and a synthetic asphaltene dispersant, p-nonylphenol, were used as additives. The addition of these components led to partial...... preparation of the mixture and the toluene content. Introduction of petroleum resins into asphaltene/heptane mixtures resulted in neutralization of the asphaltene particle charge. The addition of p-nonylphenol to asphaltene suspensions in heptane did not alter the charge of asphaltene particles. Current...

  14. Asphaltenes and Asphaltene model compounds: Adsorption, Desorption and Interfacial Rheology.

    Pradilla, Diego


    There are numerous problems encountered during extraction, production, transportation and refining of crude oil. Most of these problems are typically oil-specific, meaning that they depend upon the source of the oil, and sometimes they are reservoir-specific, meaning that they depend on the stage of extraction (primary, secondary or enhanced recovery). Nevertheless, a great part of the problems are related to the indigenous surface-active species such as asphaltenes, naphthenat...

  15. Molecular thermodynamics for prevention of asphaltene precipitation

    Wu, Jianzhong; Prausnitz, J.M.


    Crude petroleum is a complex mixture of compounds with different chemical structures and molecular weights. Asphaltenes, the heaviest and most polar fraction of crude oil, are insoluble in normal alkanes such as n-heptane, but they are soluble in aromatic solvents such as toluene. The molecular nature of asphaltenes and their role in production and processing of crude oils have been the topic of numerous studies. Under some conditions, asphaltenes precipitate from a petroleum fluid, causing severe problems in production and transportation Our research objective is to develop a theoretically based, but engineering-oriented, molecular-thermodynamic model which can describe the phase behavior of asphaltene precipitation in petroleum fluids, to provide guidance for petroleum-engineering design and production. In this progress report, particular attention is given to the potential of mean force between asphaltene molecules in a medium of asphaltene-free solvent. This potential of mean force is derived using the principles of colloid science. It depends on the properties of asphaltene and those of the solvent as well as on temperature and pressure. The effect of a solvent on interactions between asphaltenes is taken into account through its density and through its molecular dispersion properties.

  16. Quantification of asphaltene precipitation by scaling equation

    Janier, Josefina Barnachea; Jalil, Mohamad Afzal B. Abd.; Samin, Mohamad Izhar B. Mohd; Karim, Samsul Ariffin B. A.


    Asphaltene precipitation from crude oil is one of the issues for the oil industry. The deposition of asphaltene occurs during production, transportation and separating process. The injection of carbon dioxide (CO2) during enhance oil recovery (EOR) is believed to contribute much to the precipitation of asphaltene. Precipitation can be affected by the changes in temperature and pressure on the crude oil however, reduction in pressure contribute much to the instability of asphaltene as compared to temperature. This paper discussed the quantification of precipitated asphaltene in crude oil at different high pressures and at constant temperature. The derived scaling equation was based on the reservoir condition with variation in the amount of carbon dioxide (CO2) mixed with Dulang a light crude oil sample used in the experiment towards the stability of asphaltene. A FluidEval PVT cell with Solid Detection System (SDS) was the instrument used to gain experimental knowledge on the behavior of fluid at reservoir conditions. Two conditions were followed in the conduct of the experiment. Firstly, a 45cc light crude oil was mixed with 18cc (40%) of CO2 and secondly, the same amount of crude oil sample was mixed with 27cc (60%) of CO2. Results showed that for a 45cc crude oil sample combined with 18cc (40%) of CO2 gas indicated a saturation pressure of 1498.37psi and asphaltene onset point was 1620psi. Then for the same amount of crude oil combined with 27cc (60%) of CO2, the saturation pressure was 2046.502psi and asphaltene onset point was 2230psi. The derivation of the scaling equation considered reservoir temperature, pressure, bubble point pressure, mole percent of the precipitant the injected gas CO2, and the gas molecular weight. The scaled equation resulted to a third order polynomial that can be used to quantify the amount of asphaltene in crude oil.

  17. Separation and characterization of asphaltenic subfractions

    Honse, Siller O.; Ferreira, Silas R.; Mansur, Claudia R. E.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas Professora Eloisa Mano; Gonzalez, Gaspar, E-mail: [Centro de Pesquisas da PETROBRAS (CENPES), Rio de Janeiro, RJ (Brazil)


    The 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 (author)

  18. Determination of the molecular weight of asphaltenes

    Average molecular weights of asphaltenes from Colombian Barrancabermeja asphalts were determined using freezing point depression and MALDI TOF methods. Asphaltenes from different sources were used: fresh Barrancabermeja asphalt and recovered asphalt of the same origin that had been used as paving during five years. The results obtained using both techniques ate consistent and show that average molecular weight of asphaltenes from fresh asphalt is lower than the weight of asphaltenes from recovered asphalts. The freezing point depression method using benzene as solvent proved to be reliable and accurate when the temperature changes are measured with an uncertainty of +/- 0.00 1 K. The matrix preparation for the MALDI TOF method was modified using silver trifluoroacetate as ionisation promoter

  19. Asphaltenes-based polymer nano-composites

    Bowen, III, Daniel E


    Inventive composite materials are provided. The composite is preferably a nano-composite, and comprises an asphaltene, or a mixture of asphaltenes, blended with a polymer. The polymer can be any polymer in need of altered properties, including those selected from the group consisting of epoxies, acrylics, urethanes, silicones, cyanoacrylates, vulcanized rubber, phenol-formaldehyde, melamine-formaldehyde, urea-formaldehyde, imides, esters, cyanate esters, allyl resins.

  20. Rheology of asphaltene-toluene/water interfaces.

    Sztukowski, Danuta M; Yarranton, Harvey W


    The stability of water-in-crude oil emulsions is frequently attributed to a rigid asphaltene film at the water/oil interface. The rheological properties of these films and their relationship to emulsion stability are ill defined. In this study, the interfacial tension, elastic modulus, and viscous modulus were measured using a drop shape analyzer for model oils consisting of asphaltenes dissolved in toluene for concentrations varying from 0.002 to 20 kg/m(3). The effects of oscillation frequency, asphaltene concentration, and interface aging time were examined. The films exhibited viscoelastic behavior. The total modulus increased as the interface aged at all asphaltene concentrations. An attempt was made to model the rheology for the full range of asphaltene concentration. The instantaneous elasticity was modeled with a surface equation of state (SEOS), and the elastic and viscous moduli, with the Lucassen-van den Tempel (LVDT) model. It was found that only the early-time data could be modeled using the SEOS-LVDT approach; that is, the instantaneous, elastic, and viscous moduli of interfaces aged for at most 10 minutes. At longer interface aging times, the SEOS-LVDT approach was invalid, likely because of irreversible adsorption of asphaltenes on the interface and the formation of a network structure. PMID:16316096

  1. The Critical Micelle Concentration of Asphaltenes as Measured by Calorimetry

    Andersen, Simon Ivar; Christensen, S. D.


    solvent mixture) is titrated with a solution of asphaltene in the same solvent. The asphaltene concentration of the injected solution is at a level above the critical micelle concentration (CMC). In the present paper the procedure is applied in investigation of asphaltenes as well as subfractions...

  2. Investigation of Asphaltene Precipitation at Elevated Temperature

    Andersen, Simon Ivar; Lindeloff, Niels; Stenby, Erling Halfdan


    In order to obtain quantitative data on the asphaltene precipitation induced by the addition of n-alkane (heptane) at temperatures above the normal boiling point of the precipitant, a high temperature/high pressure filtration apparatus has been constructed. Oil and alkane are mixed at the...... the extracted fraction, hence there is no room for stirring. The equipment as well as solutions to some of the problems are presented along with precipitation data from 40 to 200 degrees C. The asphaltenes separated are analyzed using FT-ir. The filtrate containing the maltenes was cooled to room...

  3. Colloidal structural evolution of asphaltene studied by confocal microscopy

    Hung, Jannett; Castillo, Jimmy A.; Reyes, A.


    In this work, a detail analysis of the flocculation kinetic of asphaltenes colloidal particles has been carried out usng confocal microscopy. The colloidal structural evolution of the asphaltene flocculated has had varies postulated; however, the aggregation process of asphaltene is still not fully understood. In a recent paper, using Confocal microscope (homemade), we reported high-resolution micrographic images of asphaltenes flocculated and the correlation between crude oil stability and flocculation process. This technique permitted visualizes directly the physical nature of asphaltene flocculated. In this work, a detail analysis of the flocculation kinetic of asphaltene colloidal particles has been carried out using confocal microscopy. The physical nature of asphaltene flocculated from different crude oils is showed through of high-resolution image micrographies and its colloidal structural evolution.

  4. Asphaltene precipitates in oil production wells

    Kleinitz, W,; Andersen, Simon Ivar


    At the beginning of production in a southern German oil field, flow blockage was observed during file initial stage of production from the oil wells. The hindrance was caused by the precipitation of asphaltenes in the proximity of the borehole and in the tubings. The precipitates were of solid...

  5. Asphaltenes : interfacial aggregates characterization and film structure

    Alvarez, G.; Argillier, J.F. [Inst. Francais du Petrole, Rueil-Malmaison Cedex (France); Langevin, D. [Univ. Paris-Sud, Orsay Cedex (France). Laboratoire de Physique des Solides


    An understanding of stability mechanisms of crude oil emulsions is necessary for controlling and improving heavy oil production. The properties of the amphiphilic film that surrounds the droplets influence the behaviour of emulsions. This study examined the complex composition of asphaltenes, resins and naphtenic acids found in crude oil using a combination of techniques, such as measurement of dynamic interfacial tension and rheology of water; and modelling the oil interface where asphaltenes or naphthenic acids are dissolved. The study revealed the properties of the films. The amount of adsorbed asphaltene at the interface was determined through small-angle neutrons scattering (SANS) measurements, in which the structure of the interfacial layer and aggregates characteristics were obtained, along with UV-VIS experiments. The study showed that different parameters have a significant influence on interfacial structure and film properties, and therefore on emulsions behaviour. The parameters include naphthenic acid/asphaltene ratio, molecular weight of the naphtenic acid, pH and ionic strength of the aqueous phase. Some correlation between microscopic properties and macroscopic behaviour were obtained using stability tests on emulsions.

  6. On the Mass Balance of Asphaltene Precipitation

    Andersen, Simon Ivar; Lira-Galeana, C.; Stenby, Erling Halfdan


    In the evaluation of experimental data as well as in calculation of phase equilibria the necessity of the application of mass balances is obvious. In the case of asphaltenes the colloidal nature of these compounds may highly affect the mass balance. In the present paper several experiments are pe...

  7. Monitoring of large diesel engines through asphaltene content

    Declerck, R. [Texaco Technology Ghent (Belgium)


    Lubricants in large diesel engines, for marine and power plant application, are open contaminated with heavy fuel. This type of contamination results in blackening of the engines and deposit formation because of the coagulation of asphaltene particles. Monitoring of the asphaltene content presents the operator with important information on the condition of the engine and the lubricant. This technique was an important asset in developing a new range of lubricants highly capable of tackling the presence of asphaltenes. (orig.)

  8. Pyrolysis of petroleum asphaltenes from different geological origins and use of methylnaphthalenes and methylphenanthrenes as maturity indicators for asphaltenes

    Manoj Kumar Sarmah; Arun Borthakur; Aradhana Dutta


    Asphaltenes separated from two different crude oils from upper Assam, India, having different geological origins, viz. DK (Eocene) and JN (Oligocene–Miocene) were pyrolysed at 600°C and the products were analysed by gas chromatography–mass spectrometry (GC/MS) especially for the generated alkylnaphthalenes and alkylphenanthrenes. Both the asphaltenes produced aliphatic as well as aromatic compound classes. Alkylnaphthalenes and alkylphenanthrenes were identified by using reference chromatograms and literature data and the distributions were used to assess thermal maturity of the asphaltenes. The ratios of -substituted to α-substituted isomers of both alkylnaphthalenes and alkylphenanthrenes revealed higher maturity of the JN asphaltenes than the DK asphaltenes. For both the asphaltenes the abundance of 1-methylphenanthrene dominated over that of 9-methylphenanthrene showing the terrestrial nature of the organic matter.

  9. Pyrolysis of petroleum asphaltenes from different geological origins and use of methylnaphthalenes and methylphenanthrenes as maturity indicators for asphaltenes

    Manoj Kumar Sarmah; Arun Borthakur; Aradhana Dutta


    Asphaltenes separated from two different crude oils from upper Assam, India, having different geological origins, viz. DK(eocene) and JN (oligocene–miocene) were pyrolysed at 600 °C and the products were analysed by gas chromatography–mass spectrometry (GC/MS) especially for the generated alkylnaphthalenes and alkylphenanthrenes. Both the asphaltenes produce aliphatic as well as aromatic compound classes. Alkylnaphthalenes and alkylphenanthrenes were identified by using reference chromatograms and literature data and the distributions used to assess thermalmaturity of the asphaltenes. The ratios of -substituted to -substituted isomers of both alkylnaphthalenes and alkylphenanthrenes revealed higher maturity of the JN asphaltenes than the DK asphaltenes. For both the asphaltenes, the abundance of 1-methylphenanthrene dominates over that of 9-methylphenanthrene showing the terrestrial nature of the organic matter.

  10. Effect of asphaltenes on crude oil wax crystallization

    Kriz, Pavel; Andersen, Simon Ivar


    The paper summarizes the experimental work done on asphaltene influenced wax crystallization. Three different asphaltenes (from stable oil, instable oil, and deposit) were mixed at several concentrations or dispersions into the waxy crude oil. These blends were evaluated by viscometry and yield...... stress measurement and compared with the original crude oil. A complex asphaltene−wax interaction as a function of asphaltene concentration and degree of asphaltene dispersion under dynamic and static condition was observed. The crystallization and the wax network strength was strongly dependent...

  11. Separation of Asphaltenes by Polarity using Liquid-Liquid Extraction

    Andersen, Simon Ivar


    In order to investigate the nature of petroleum asphaltenes in terms of polarity a process was developed using initial liquid-liquid extraction of the oil phase followed by precipitation of the asphaltenes using n-heptane. The liquid-liquid extraction was performed using toluene-methanol mixtures...... with increasing content of toluene. Although large fractions of the crude oil (Alaska ´93) was extracted in the higher polarity solvents (high concentration of methanol), the asphaltene content of the dissolved material was low. As the toluene content increased more asphaltenes were transferred to the...... extracted in the high polarity solvents....

  12. Study of asphaltene precipitation by Calorimetry

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David; Andersen, Simon Ivar; Stenby, Erling Halfdan; Carrier, Hervé


    Can calorimetry bring new input to the Current understanding of asphaltene precipitation? In this work, two types of precipitation were studied by means of calorimetry: addition of n-heptane into asphaltene solutions and temperature/pressure variations on a recombined live oil. The first series of...... experiments showed that weak forces determine precipitation. Indeed, isothermal titration calorimetry could not detect any clear signal although this technique can detect low-energy transitions such as liquid-liquid equilibrium and rnicellization. The second series of tests proved that precipitation caused by...... T and P variations is exothermic for this system. Furthermore, the temperature-induced precipitation is accompanied by an increase in the apparent thermal expansivity. Therefore, it seems that these two phase transitions exhibit different calorimetric behaviours and they may not be as similar as...

  13. Asphaltene analysis using size exclusion chromatogrphy

    Lynch, A.W.; Thomas, M.G.


    A common technique used in coal liquefaction investigations is the asphaltene analysis, whereby products are separated into four major fractions (insolubles, preasphaltenes, asphaltenes and oils) by solvent extraction techniques. The fractions are defined by their solubility in organic solvents such as tetrahydrofuran, toluene and pentane. An instrumental method of analysis, using gel permeation liquid chromatography, was developed to reduce the problems with the conventional solvent separation. The technique relies upon the fact that the fractions differ in molecular size as well as solubility. The method uses one solvent (THF) and a single 100A microstyragel column to separate the three soluble fractions. The trends in the data obtained with the molecular size separation agree with the trends obtained by conventional solvent separation on the same samples. (5 refs.)

  14. Investigation of Asphaltene Precipitation at Elevated Temperature

    Andersen, Simon Ivar; Lindeloff, Niels; Stenby, Erling Halfdan


    appropriate temperature and the pressure in closed vessels keeping the mixture at the liquid state. The filtration is performed with a small differential pressure over the filter so as to avoid flashing the mixture. The technique requires a low dead volume in the system to minimize the content of maltenes in...... the extracted fraction, hence there is no room for stirring. The equipment as well as solutions to some of the problems are presented along with precipitation data from 40 to 200 degrees C. The asphaltenes separated are analyzed using FT-ir. The filtrate containing the maltenes was cooled to room...... temperature and the asphaltenes separating upon cooling was collected and analyzed. The oil and selected maltene fractions and extraction/cleaning solvents were analyzed using GC....


    James A. Guin; Ganesh Ramakrishnan; Keiji Asada


    During this past six months we continued our ongoing studies of the diffusion controlled uptake of coal and petroleum asphaltenes into a porous carbon catalyst. Toluene was used as the solvent for experiments at 20 C and 75 C while 1-methylnaphthalene was the solvent for the higher temperature experiments at 100 C, 150 C and 250 C. All runs were made at a pressure of 250 psi (inert He gas). Experiments were performed at 20 C and 75 C, for the petroleum asphaltene/toluene system. For the coal asphaltene/toluene system, experiments were performed at 75 C. Experiments were performed at 100 C, 150 C and 250 C for the coal asphaltene/1-methylnaphthalene system. A comparison between the experimental data and model simulated data showed that the mathematical model satisfactorily fitted the adsorptive diffusion of both the coal and petroleum asphaltenes onto a porous activated carbon. The adsorption constant decreases with an increase in temperature for both, the coal asphaltene/1-methylnaphthalene system as well as the petroleum asphaltene/toluene system. It was found that the adsorption constant for the coal asphaltene/toluene system at 75 C was much higher than that of the petroleum asphaltene/toluene system at the same temperature providing evidence of the greater affinity of the coal asphaltenes for the carbon surface. This could be due to the presence of more functional heteroatomic groups in the coal asphaltenes compared to their petroleum counterparts. Also during this time period, a new carbon catalyst support was prepared in our laboratory which will be used in adsorption experiments during the next phase of work.

  16. Asphaltene and solids-stabilized water-in-oil emulsions

    Sztukowski, Danuta M.

    Water-in-crude oil emulsions are a problem in crude oil production, transportation, and processing. Many of these emulsions are stabilized by asphaltenes and native oilfield solids adsorbed at the oil-water interface. Design of effective emulsion treatments is hampered because there is a lack of understanding of the role asphaltenes and solids play in stabilizing these emulsions. In this work, the structural, compositional and rheological properties of water/hydrocarbon interfaces were determined for model emulsions consisting of water, toluene, heptane, asphaltenes and native oilfield solids. The characteristics of the interface were related to the properties of asphaltenes and native solids. Emulsion stability was correlated to interfacial rheology. A combination of vapour pressure osmometry, interfacial tension and emulsion gravimetric studies indicated that asphaltenes initially adsorb at the interface as a monolayer of self-associated molecular aggregates. It was demonstrated why it is necessary to account for asphaltene self-association when interpreting interfacial measurements. The interfacial area of Athabasca asphaltenes was found to be approximately 1.5 nm2 and did not vary with concentration or asphaltene self-association. Hence, more self-associated asphaltenes simply formed a thicker monolayer. The interfacial monolayer observed in this work varied from 2 to 9 nm in thickness. The asphaltene monolayer was shown to adsorb reversibly only at short interface aging times. The film gradually reorganizes at the interface to form a rigid, irreversibly adsorbed network. The elastic and viscous moduli can be modeled using the Lucassen-van den Tempel (LVDT) model when the aging time is less than 10 minutes. An increase in film rigidity can be detected with an increase in the total elastic modulus. Increased film rigidity was shown to reduce the rate of coalescence in an emulsion and increase overall emulsion stability (reduce free water resolution). The rate of

  17. Study on the polarity, solubility, and stacking characteristics of asphaltenes

    Zhang, Long-li


    The structure and transformation of fused aromatic ring system in asphaltenes play an important role in the character of asphaltenes, and in step affect the properties of heavy oils. Polarity, solubility and structural characteristics of asphaltenes derived from Tahe atmospheric residue (THAR) and Tuo-826 heavy crude oil (Tuo-826) were analyzed for study of their internal relationship. A fractionation method was used to separate the asphaltenes into four sub-fractions, based on their solubility in the mixed solvent, for the study of different structural and physical-chemical properties, such as polarity, solubility, morphology, stacking characteristics, and mean structural parameters. Transmission electron microscope (TEM) observation can present the intuitive morphology of asphaltene molecules, and shows that the structure of asphaltenes is in local order as well as long range disorder. The analysis results showed that n-heptane asphaltenes of THAR and Tuo-826 had larger dipole moment values, larger fused aromatic ring systems, larger mean number of stacking layers, and less interlayer spacing between stacking layers than the corresponding n-pentane asphaltenes. The sub-fractions that were inclined to precipitate from the mixture of n-heptane and tetrahydrofuran had larger polarity and less solubility. From the first sub-fraction to the fourth sub-fraction, polarity, mean stacking numbers, and average layer size from the TEM images follow a gradual decrease. The structural parameters derived from TEM images could reflect the largest fused aromatic ring system in asphaltene molecule, yet the parameters derived from 1H NMR data reflected the mean message of poly-aromatic ring systems. The structural parameters derived from TEM images were more consistent with the polarity variation of sub-fractions than those derived from 1H NMR data, which indicates that the largest fused aromatic ring system will play a more important role in the stacking characteristics of

  18. Interfacial tension change due to asphaltene flocculation in recombined oils

    Carrier, H.; Pauly, J.; Daridon, J.L. [Univ. de Pau, Pau Cedex (France). Laboratoire des Fluides Complexes; Mejia, A. [Univ. de Pau, Pau Cedex (France). Laboratoire des Fluides Complexes; Univ. Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of). Facultad de Ciencias; Castillo, J. [Univ. Central de Venezuela, Caracas (Venezuela, Bolivarian Republic of). Facultad de Ciencias


    Asphaltenes found in reservoirs fluids may dissolve as colloidal aggregates in crude oils. The aggregates might destabilize as a result of changes in both temperature and pressure, resulting in flocculation of asphaltenes. The insolubility of asphaltenes can cause major problems at different stages of oil production, such as deposition and flow blockage. In order to evaluate the risk of asphaltene formation and to design techniques to prevent asphaltene deposits, it is necessary to measure and predict the conditions of flocculation throughout the pressures encountered from reservoir to surface conditions. To date, most asphaltene stability studies have been conducted at atmospheric pressure for dead oils by adding precipitating solvents. However the relationship of these stability tests with asphaltene flocculation due to the decompression of live oil in reservoir or production conditions is not fully established. Accurate measurements on both atmospheric and field conditions are needed. In order to address this problem, a high-pressure device using refractive index measurements and a filtration technique was designed to measure onset of asphaltene flocculation in live oils. The capacity of the device was also extended to investigate the evolution of the interfacial tension between crude oil and gases or immiscible liquids such as water, at pressures up to 70 MPa. Interfacial tension was measured by axisymmetric drop shape analysis of a pendant oil drop. The study found that a relationship exists between the discontinuity in the trend of the superficial tension as a function of the pressure and the threshold of asphaltenes aggregation due to decompression. The study provided evidence of the effect of asphaltenes flocculation on the interfacial tension. 2 refs.

  19. Structural Study of Asphaltenes from Iranian Heavy Crude Oil

    Davarpanah L.


    Full Text Available In the present study, asphaltene precipitation from Iranian heavy crude oil (Persian Gulf off-shore was performed using n-pentane (n-C5 and n-heptane (n-C7 as light alkane precipitants. Several analytical techniques, each following different principles, were then used to structurally characterize the precipitated asphaltenes. The yield of asphaltene obtained using n-pentane precipitant was higher than asphaltene precipitated with the use of n-heptane. The asphaltene removal affected the n-C5 and n-C7 maltene fractions at temperatures below 204°C, as shown by the data obtained through the simulated distillation technique. Viscosity of heavy oil is influenced by the asphaltene content and behavior. The viscosity dependence of the test heavy oil on the shear rate applied was determined and the flow was low at y. above 25 s-1 . The reconstituted heavy oil samples were prepared by adding different amounts of asphaltenes to the maltenes (deasphalted heavy oil and asphaltene effects were more pronounced at the low temperature of 25°C as compared with those at the higher temperatures. According to the power law model used in this study the flowability of the test heavy oil exhibited a pseudoplastic character. Structural results obtained from Fourier Transform InfraRed (FTIR spectroscopy showed the presence of the different functional groups in the precipitated asphaltenes. For instance, the presence of different hydrocarbons (aliphatic, aromatic and alicyclic based on their characteristics in the FTIR spectra was confirmed. Resins are effective dispersants, and removal of this fraction from the crude oil is disturbing to the colloidal nature of heavy oil; asphaltene flocculation and precipitation eventually occur. Appearance of pores in the Scanning Electron Microscopy (SEM images was used as an indicator of the resin detachment. With the use of 1H and 13C Nuclear Magnetic Resonance (NMR spectroscopy, two important structural parameters of the

  20. Asphaltene precipitates in oil production wells

    Kleinitz, W,; Andersen, Simon Ivar


    compounds in the organic scales from operations definitely differed from the data published in the literature. In order to dissolve the precipitates and thus eliminate the damage, various organic solvents and industrial solvent mixtures were examined. The kinetics of the dissolution process in operational...... subsequently resumed in these wells. The production from the wells was adjusted in such a way that the conditions for asphaltene deposition are effectively suppressed for several years. The long-term success of the treatment tons also supported by modifying the production strategy. The process of optimising...

  1. Role of asphaltenes in stabilizing thin liquid emulsion films.

    Tchoukov, Plamen; Yang, Fan; Xu, Zhenghe; Dabros, Tadeusz; Czarnecki, Jan; Sjöblom, Johan


    Drainage kinetics, thickness, and stability of water-in-oil thin liquid emulsion films obtained from asphaltenes, heavy oil (bitumen), and deasphalted heavy oil (maltenes) diluted in toluene are studied. The results show that asphaltenes stabilize thin organic liquid films at much lower concentrations than maltenes and bitumen. The drainage of thin organic liquid films containing asphaltenes is significantly slower than the drainage of the films containing maltenes and bitumen. The films stabilized by asphaltenes are much thicker (40-90 nm) than those stabilized by maltenes (∼10 nm). Such significant variation in the film properties points to different stabilization mechanisms of thin organic liquid films. Apparent aging effects, including gradual increase of film thickness, rigidity of oil/water interface, and formation of submicrometer size aggregates, were observed for thin organic liquid films containing asphaltenes. No aging effects were observed for films containing maltenes and bitumen in toluene. The increasing stability and lower drainage dynamics of asphaltene-containing thin liquid films are attributed to specific ability of asphaltenes to self-assemble and form 3D network in the film. The characteristic length of stable films is well beyond the size of single asphaltene molecules, nanoaggregates, or even clusters of nanoaggregates reported in the literature. Buildup of such 3D structure modifies the rheological properties of the liquid film to be non-Newtonian with yield stress (gel like). Formation of such network structure appears to be responsible for the slower drainage of thin asphaltenes in toluene liquid films. The yield stress of liquid film as small as ∼10(-2) Pa is sufficient to stop the drainage before the film reaches the critical thickness at which film rupture occurs. PMID:24564447

  2. A study of asphaltene solubility and precipitation

    Hong E.; Paul Watkinson [University of British Columbia, Vancouver, BC (Canada). Department of Chemical and Biological Engineering


    The effects of diluent composition on asphaltene precipitation from Cold Lake vacuum residue and Athabasca atmospheric tower bottoms were determined using the hot filtration method at 60-85{sup o}C. For selected mixtures the temperature range was extended to 300{sup o}C. The diluents include pure n-alkanes, a lube oil base-stock, a heavy vacuum gas oil and a resin-enriched fraction recovered from Cold Lake vacuum residue by supercritical fluid extraction and fractionation. The latter three complex diluents were tested alone and in blends, in order to cover a range of saturates from 56 to 99.4 wt%, aromatics from 0.6 to 25 wt%, and resins from 0 to 19 wt%. The scaling equation proposed by Rassamdana et al. in which the weight percent of asphaltenes precipitated is expressed as a function of alkane to feed ratio, and the alkane molecular mass, gave good agreement with the data for the pure alkane diluents. For the more complex diluents, an extension to the scaling equation was developed with two additional variables (the density and saturate content of the diluents). This equation provided good agreement with the data over a wide range of diluent to feed ratios. By the addition of the colloidal instability index of the feed oil into the variables of the scaling equation, the precipitation data from the two different feed oils could be correlated. 13 refs., 8 figs., 3 tabs.

  3. Chemical composition of asphaltenes from thermal dissociation of brown coal

    Evstaf' ev, S.N.; Denisova, T.I.; Tuturina, V.V.


    Investigates chemical composition of asphaltenes and preasphaltenes separated from liquid products of thermal dissociation of Azeisk deposit brown coal in tetralin. Asphaltenes and preasphaltenes represent a mixture of mainly aromatic compounds containing bi- and tri-cyclic aromatic fractions differing by length of aliphatic substituents and by distribution of oxygen-containing functional groups. Describes tests carried out at 300-420 C in autoclaves using 0.1-0.3 mm coal particles and tetralin containing decalin (2.8%) and naphthalene (5.2%). Establishes that asphaltenes soluble in acetone are represented by low-molecular saturated compounds; about 60% of oxygen in asphaltenes and preasphaltenes is attached to ethereal and heterocyclic structure groups. 10 refs.

  4. A chemical process of asphaltenes dispersion : anticor DSA 700

    This work deals with asphalts dispersion chemical process. Asphaltenes are constituents of petroleum which under chemical, physical or mechanical variations effect precipitate and create deposits. In order to cope with this problem, a product : Anticor DSA 700 has been adjusted and allow to stabilize asphaltenes. This method has already been used in France and in Algeria and will be extended to others west countries. (O.L.). 2 figs


    James A. Guin; Ganesh Ramakrishnan


    During this time period, experiments were performed to study the diffusion controlled uptake of quinoline and a coal asphaltene into porous carbon catalyst pellets. Cyclohexane and toluene were used as solvents for quinoline and the coal asphaltene respectively. The experiments were performed at 27 C and 75 C, at a pressure of 250 psi (inert gas) for the quinoline/cyclohexane system. For the coal asphaltene/toluene system, experiments were performed at 27 C, also at a pressure of 250 psi. These experiments were performed in a 20 cm{sup 3} microautoclave, the use of which is advantageous since it is economical from both a chemical procurement and waste disposal standpoint due to the small quantities of solvents and catalysts used. A C++ program was written to simulate data using a mathematical model which incorporated both diffusional and adsorption mechanisms. The simulation results showed that the mathematical model satisfactorily fitted the adsorptive diffusion of quinoline and the coal asphaltene onto a porous activated carbon. For the quinoline/cyclohexane system, the adsorption constant decreased with an increase in temperature. The adsorption constant for the coal asphaltene/toluene system at 27 C was found to be much higher than that of the quinoline/cyclohexane system at the same temperature. Apparently the coal asphaltenes have a much greater affinity for the surface of the carbon catalyst than is evidenced by the quinoline molecule.

  6. Novel stationary phases based on asphaltenes for gas chromatography.

    Boczkaj, Grzegorz; Momotko, Malwina; Chruszczyk, Dorota; Przyjazny, Andrzej; Kamiński, Marian


    We present the results of investigations on the possibility of the application of the asphaltene fraction isolated from the oxidized residue from vacuum distillation of crude oil as a stationary phase for gas chromatography. The results of the investigation revealed that the asphaltene stationary phases can find use for the separation of a wide range of volatile organic compounds. The experimental values of Rohrschneider/McReynolds constants characterize the asphaltenes as stationary phases of medium polarity and selectivity similar to commercially available phases based on alkyl phthalates. Isolation of asphaltenes from the material obtained under controlled process conditions allows the production of a stationary phase having reproducible sorption properties and chromatographic columns having the same selectivity. Unique selectivity and high thermal stability make asphaltenes attractive as a material for stationary phases for gas chromatography. A low production cost from a readily available raw material (oxidized petroleum bitumens) is an important economic factor in case of application of the asphaltene stationary phases for preparative and process separations. PMID:27144876

  7. Modelling the effect of gas injections on the stability of asphaltene-containing crude oils

    Zhang, X.; Moorwood, T. [Infochem, Munich (Germany); Merino Garcia, D.; Pena Diez, J.L. [Repsol YPF, Madrid (Spain)


    In oil fields where asphaltene deposits occur, they present major remediation problems and can halt production due to flow blockage. Crude oils which precipitate asphaltenes generally contain both asphaltene molecules and lighter resin molecules. Resins are thought to solvate the asphaltene molecules, thus stabilizing the solution, while light gases have the opposite effect. In order to model asphaltene phase behaviour, it is important to understand the impact of adding gas to asphaltene-containing crudes. This study presented several experimental investigations of gas injection into asphaltene-containing crudes. The trends of asphaltene destabilization were discussed. The injection gases ranged from pure gases to a gas condensate. The data were modelled using a conventional equation of state together with an extra term that considered the association between asphaltene molecules and their solvation by resins. Since the model could simultaneously described the gas, oil and asphaltene phases, it was possible to calculate phase stability and phase equilibria. However, a different model had to be used to obtain the gas-oil equilibrium because the use of solubility parameters only allows the stability of the asphaltene phase to be calculated. The model correctly predicted that the gases will promote asphaltene precipitation. In its original form, the model tended to over-predict the trend. The optimal parameter values needed to represent all the available experimental data were determined. The extent to which the effect of gas injection on asphaltenes can be predicted was then discussed.

  8. Comparisons Between Asphaltenes from the Dead and Live-Oil Samples of the Same Crude Oils

    Aquino-Olivos, M.A.; Andersen, Simon Ivar; Lira-Galeana, C.


    extracted and analyzed. These pressure-driven asphaltenes found on the filter were found to make up in the range between 50 and 100 ppm of the whole crude oil. Opening of the cell did not reveal asphaltenes retained due to wall adhesion. Size exclusion chromatography tests performed on both the live-oil......-derived asphaltenes and the standard asphaltenes as precipitated by atmospheric titration on the same crude oil, revealed that the live-oil asphaltenes had apparent smaller hydrodynamic volume and narrower distributions than the standard asphaltenes for two oils. Further FTIR tests also showed large differences......Asphaltenes precipitated from pressure-preserve bottomhole oil samples have been obtained for three oils at different pressures, using a bulk high-pressure filtration apparatus. The precipitates captured on the filter were recovered, the asphaltenes defined by the n-heptane insolubility were...

  9. Comparisons Between Asphaltenes from the Dead and Live-Oil Samples of the Same Crude Oils

    Aquino-Olivos, M.A.; Andersen, Simon Ivar; Lira-Galeana, C.


    Asphaltenes precipitated from pressure-preserve bottomhole oil samples have been obtained for three oils at different pressures, using a bulk high-pressure filtration apparatus. The precipitates captured on the filter were recovered, the asphaltenes defined by the n-heptane insolubility were...... extracted and analyzed. These pressure-driven asphaltenes found on the filter were found to make up in the range between 50 and 100 ppm of the whole crude oil. Opening of the cell did not reveal asphaltenes retained due to wall adhesion. Size exclusion chromatography tests performed on both the live-oil......-derived asphaltenes and the standard asphaltenes as precipitated by atmospheric titration on the same crude oil, revealed that the live-oil asphaltenes had apparent smaller hydrodynamic volume and narrower distributions than the standard asphaltenes for two oils. Further FTIR tests also showed large differences...

  10. New method for the onset point determination of the petroleum asphaltene aggregation

    Work has been devoted to investigation of the process of asphaltenes aggregation in a model system asphaltene-toluene-heptane. The procedure of the onset point determination of the petroleum asphaltenes which is based on the method of photon correlation spectroscopy has been described. Two ways have been developed to determine the onset of asphaltenes aggregation by means of method of photon correlation spectroscopy. The first method allows defining the onset of asphaltenes aggregation of light scattering intensity depending on the quantity of n-alkane in the model system. The second method allows determining the onset point of asphaltenes aggregation parameter k depending on the quantity of n-alkane. A comparative evaluation of onset points, obtained in different ways has been given. The influence of the model system composition on the process of asphaltenes aggregation has been studied. The characteristic diffusion time of asphaltenes has been calculated

  11. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    Rajagopal K.; Silva S. M. C.


    The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10...

  12. Correlations between SARA Fractions, Density, and RI to Investigate the Stability of Asphaltene

    Ali Chamkalani


    Asphaltene precipitation is one of the most common problems in both oil recovery and refinery processes. Its deposition causes many problems mainly because of the fuzzy nature of asphaltene and the large number of parameters affecting precipitation. Unfortunately there is not a predictive technique for screening it. Refractive index (RI) was used as a stability test for asphaltene which makes a quantitative judgment for asphaltene stability. In our study, we first represent a novel correlatio...

  13. Asphaltene flocculation and collapse from petroleum fluids

    Branco, Valter Antonio M.; De Almeida Xavier, Luiza Cristina [Petroleo Brasilerio S.A., Petrobras/CENPES/DIGER, Cidade Universitaria, Quadra 7, Ilma Fundao, RJ, 21910 Rio de Janeiro (Brazil); Mansoori, G. Ali; Park, Sang J.; Manafi, Hussain [Thermodynamics Research Laboratory, Department of Chemical Engineering, University of Illinois at Chicago, 810 S. Clinton Street, 60607-7000 Chicago, IL (United States)


    Deposition of complex and heavy organic compounds, which exist in petroleum crude and heavy oil, can cause a number of severe problems. To prevent deposition inside the reservoir, in the well head and inside the transmission lines, it is necessary to be able to predict the onset and amount of deposition due to various factors. In the present paper, the mechanism of asphaltene deposition, which is the major cause of most organic deposition cases, is modeled based on statistical mechanics of polydisperse polymer solutions joined with the kinetic theory of aggregation and its predictive capability is discussed. Utilization of statistical mechanics of polydisperse polymer solutions joined with kinetic theory of aggregation enables us to develop a realistic model which is able to predict both reversible and irreversible heavy organic depositions. The present model is capable of describing several reversible and irreversible situations, such as the phenomena of organic deposition, growing mechanism of heavy organic aggregates, the size distributions of precipitated organics and the solubility of heavy organics in a crude oil due to variations in oil pressure, temperature and composition. As an example, the present model is applied for heavy organics deposition prediction of two different Brazilian crude oils for which experimental data are available. It is shown that the prediction results of the present model are in good agreement with the experimental data.

  14. Cooee bitumen. II. Stability of linear asphaltene nanoaggregates

    Lemarchand, Claire; Schrøder, Thomas; Dyre, J. C.;


    chose first to consider the simple case where only asphaltene molecules are counted in a nanoaggregate. We used a master equation approach and a related statistical mechanics model. The linear asphaltene nanoaggregates behave as a rigid linear chain. The most complicated case where all aromatic......Asphaltene and smaller aromatic molecules tend to form linear nanoaggregates in bitumen. Over the years bitumen undergoes chemical aging and during this process, the size of the nanoaggregate increases. This increase is associated with an increase in viscosity and brittleness of the bitumen...... molecules are counted in a nanoaggregate is then discussed. The linear aggregates where all aromatic molecules are counted seem to behave as a flexible linear chain...

  15. Hindered Diffusion of Asphaltenes at Evaluated Temperature and Pressure

    James A. Guin; Surya Vadlamani; Xiafeng Yang


    During this time period, uptake experiments were performed at elevated temperatures up to 280 o C for the adsorptive diffusion of a coal asphaltene in 1- methylnaphthalene onto alumina catalyst pellets. Model simulation results showed that a mathematical model incorporating diffusion and adsorption mechanisms satisfactorily fitted the adsorptive diffusion of coal asphaltenes onto the alumina catalyst in a fairly wide temperature range of 55 o C to 280 o C. The logarithm of the adsorption constant, obtained by simulating the experimental data with the model solution, was found to be linearly dependent on temperature. As temperature increased, the value of the adsorption constant decreased. On the other hand, the effective diffusivity of the asphaltene increased with temperature. These off-setting temperature dependencies resulting from the adsorption constant and the effective diffusivity compensated at least to some extent in the uptake process.

  16. Thin film pyrolysis of oil sands asphaltenes for structural analysis

    Karimi, Arash; Gray, Murray R [Department of Chemical and Materials Engineering, University of Alberta (Canada); Qian, Kuangnan; Olmstead, William N.; Freund, Howard [ExxonMobil Research and Engineering (United States)], email:


    Current methods to extract asphaltene building blocks only produce small sample quantities per batch for analysis. To reach sample quantities sufficient for several analytical methods on each batch, the following method was investigated in a preliminary study. Asphaltenes from Alberta bitumen were spray coated as thin films on alloy plates to be used in controlled pyrolysis. Each batch of six plates reacted around 1 g of asphaltenes in the furnace. Reaction products were purged from the reaction chamber with cold nitrogen, then cooled in a cold trap. Gases were collected and analysed using gas chromatography. Liquid products were condensed in a cold trap, rinsed with solvent, and evaporated overnight. The coke was also recovered from the plates and analysed. The method yielded mass balances greater than 90%. Products analysis revealed molecular fragment sizes ranging from C10 to C100. Lighter components (C5-C10) were not detected, having probably evaporated during solvent removal.

  17. Polymeric dispersants delay sedimentation in colloidal asphaltene suspensions.

    Hashmi, Sara M; Quintiliano, Leah A; Firoozabadi, Abbas


    Asphaltenes, among the heaviest components of crude oil, can become unstable under a variety of conditions and precipitate and sediment out of solution. In this report, we present sedimentation measurements for a system of colloidal scale asphaltene particles suspended in heptane. Adding dispersants to the suspension can improve the stability of the system and can mediate the transition from a power-law collapse in the sedimentation front to a rising front. Additional dispersant beyond a crossover concentration can cause a significant delay in the dynamics. Dynamic light scattering measurements suggest that the stabilization provided by the dispersants may occur through a reduction of both the size and polydispersity of the asphaltene particles in suspension. PMID:20334407

  18. Cooee bitumen II: Stability of linear asphaltene nanoaggregates

    Lemarchand, Claire A; Dyre, Jeppe C; Hansen, Jesper S


    Asphaltene and smaller aromatic molecules tend to form linear nanoaggregates in bitumen.Over the years bitumen undergoes chemical aging and during this process, the size of the nanoaggregate increases. This increase is associated with an increase in viscosity and brittleness of the bitumen, eventually leading to road deterioration. This paper focuses on understanding the mechanisms behind nanoaggregate size and stability. We used molecular dynamics simulations to quantify the probability of having a nanoaggregate of a given size in the stationary regime. To model this complicated behavior, we chose first to consider the simple case where only asphaltene molecules are counted in a nanoaggregate. We used a master equation approach and a related statistical mechanics model. The linear asphaltene nanoaggregates behave as a rigid linear chain. The most complicated case where all aromatic molecules are counted in a nanoaggregate is then discussed. The linear aggregates where all aromatic molecules are counted seem ...

  19. Cooee bitumen. II. Stability of linear asphaltene nanoaggregates

    Lemarchand, Claire A.; Schrøder, Thomas B.; Dyre, Jeppe C.; Hansen, Jesper S.


    Asphaltene and smaller aromatic molecules tend to form linear nanoaggregates in bitumen. Over the years bitumen undergoes chemical aging and during this process, the size of the nanoaggregate increases. This increase is associated with an increase in viscosity and brittleness of the bitumen, eventually leading to road deterioration. This paper focuses on understanding the mechanisms behind nanoaggregate size and stability. We used molecular dynamics simulations to quantify the probability of having a nanoaggregate of a given size in the stationary regime. To model this complicated behavior, we chose first to consider the simple case where only asphaltene molecules are counted in a nanoaggregate. We used a master equation approach and a related statistical mechanics model. The linear asphaltene nanoaggregates behave as a rigid linear chain. The most complicated case where all aromatic molecules are counted in a nanoaggregate is then discussed. The linear aggregates where all aromatic molecules are counted seem to behave as a flexible linear chain.

  20. Stability and demulsification of emulsions stabilized by asphaltenes or resins.

    Xia, Lixin; Lu, Shiwei; Cao, Guoying


    Experimental data are presented to show the influence of asphaltenes and resins on the stability and demulsification of emulsions. It was found that emulsion stability was related to the concentrations of the asphaltene and resin in the crude oil, and the state of dispersion of the asphaltenes and resins (molecular vs colloidal) was critical to the strength or rigidity of interfacial films and hence to the stability of the emulsions. Based on this research, a possible emulsion minimization approach in refineries, which can be implemented utilizing microwave radiation, is also suggested. Comparing with conventional heating, microwave radiation can enhance the demulsification rate by an order of magnitude. The demulsification efficiency reaches 100% in a very short time under microwave radiation. PMID:14972628

  1. Degradation of Asphaltenic Fraction by Locally Isolated Halotolerant Bacterial Strains

    Ali, Hager R.; Nour Sh. El-Gendy; Moustafa, Yasser M.; Roushdy, Mohamed I.; Hashem, Ahmed I.


    Three halotolerant bacterial species were isolated from locally oil-polluted water sample for their ability to utilize asphaltene (Asph) fraction as sole carbon and energy source. These bacteria degrade 83–96% of 2500 mg/L asphaltene within 21 d at 30°C and pH7. They were identified as Bacillus sp. Asph1, Pseudomonas aeruginosa Asph2, and Micrococcus sp. Asph3. A statistically significant difference at 95% confidence level for cell growth and percentage biodegradation (%BD) was observed in al...

  2. The effect of asphaltene particle size and distribution on the temporal advancement of the asphaltene deposition profile in the well column

    Zeinali Hasanvand, Mahdi; Mosayebi Behbahani, Reza; Feyzi, Farzaneh; Ali Mousavi Dehghani, Seyed


    Asphaltene deposition in oil wells is an inconvenient production problem. Generating a precise deposition model for the well column is essential for optimal well design and prevention/reduction of deposition-associated difficulties. The goal of this study is to determine the effects of various parameters on the deposition process. These parameters include oil viscosity, temperature, flow velocity, well diameter and asphaltene particle size and particle size distribution. The first five parameters are analyzed using Escobedo and Mansoori (2010), Cleaver and Yates (1975) and Friedlander and Johnstone (1957) asphaltene deposition models. The last parameter (asphaltene particle size distribution) is not directly included in the asphaltene deposition models. Therefore, a dynamic well column model is generated by combining transport phenomena (mass, heat and momentum transfer) equations with thermodynamic models. The model is fine-tuned and verified based on field data from an Iranian producing oil well with frequent asphaltene deposition problem and subsequently used for predicting the time-dependent development of the asphaltene deposition profile in the well column for a series of asphaltene particle size distributions. The results show the effect of the said parameters depends on how the buffer layer and Brownian motion are defined. The Escobedo and Mansoori (2010) model is found to make better predictions of deposited asphaltene in the studied well.

  3. Enhanced Oil Recovery (EOR by Miscible CO2 and Water Flooding of Asphaltenic and Non-Asphaltenic Oils

    Edwin A. Chukwudeme


    Full Text Available An EOR study has been performed applying miscible CO2 flooding and compared with that for water flooding. Three different oils are used, reference oil (n-decane, model oil (n-C10, SA, toluene and 0.35 wt % asphaltene and crude oil (10 wt % asphaltene obtained from the Middle East. Stearic acid (SA is added representing a natural surfactant in oil. For the non-asphaltenic oil, miscible CO2 flooding is shown to be more favourable than that by water. However, it is interesting to see that for first years after the start of the injection (< 3 years it is shown that there is almost no difference between the recovered oils by water and CO2, after which (> 3 years oil recovery by gas injection showed a significant increase. This may be due to the enhanced performance at the increased reservoir pressure during the first period. Maximum oil recovery is shown by miscible CO2 flooding of asphaltenic oil at combined temperatures and pressures of 50 °C/90 bar and 70 °C/120 bar (no significant difference between the two cases, about 1% compared to 80 °C/140 bar. This may support the positive influence of the high combined temperatures and pressures for the miscible CO2 flooding; however beyond a certain limit the oil recovery declined due to increased asphaltene deposition. Another interesting finding in this work is that for single phase oil, an almost linear relationship is observed between the pressure drop and the asphaltene deposition regardless of the flowing fluid pressure.

  4. Asphaltene detection using surface enhanced Raman scattering (SERS).

    Alabi, O O; Edilbi, A N F; Brolly, C; Muirhead, D; Parnell, J; Stacey, R; Bowden, S A


    Surface enhanced Raman spectroscopy using a gold substrate and excitation at 514 nm can detect sub parts per million quantities of asphaltene and thereby petroleum. This simple format and sensitivity make it transformative for applications including sample triage, flow assurance, environmental protection and analysis of unique one of a kind materials. PMID:25812164

  5. Langmuir films of asphaltene model compounds and their fluorescent properties.

    Nordgård, Erland L; Landsem, Eva; Sjöblom, Johan


    The relationship between the physicochemical properties of asphaltenes and asphaltene structure is an issue of increasing focus. Surface pressure-area isotherms of asphaltene model compounds have been investigated to gain more knowledge of their arrangement at an aqueous surface. Variations in interfacial activity have been correlated to proposed arrangements. The presence of a carboxylic acid has shown to be crucial for their interfacial activity and film properties. The acid group directs the molecules normal to the surface, forming a stable monolayer film. The high stability was absent when no acidic groups were present. Fluorescence spectra of deposited Langmuir-Blodgett films showed only the presence of the excimer emission for thin films of acidic model compounds, indicating a close face-to-face arrangement of the molecules. Time-correlated single photon counting (TCSPC) of the model compounds in toluene indicated the presence of aggregates for two of four compounds at low concentrations. However, a sudden drop of interfacial tension observed could not be correlated to the aggregation. Instead, aggregation induced by addition of a "poor" solvent showed decreased interfacial activity when aggregated due to decrease of monomers in bulk. The findings regarding these asphaltene model compounds and their structural differences show the great effect an acidic group has on their physicochemical properties. PMID:18652499

  6. A Thermodynamic Mixed-Solid Asphaltene Precipitation Model

    Lindeloff, Niels; Heidemann, R.A.; Andersen, Simon Ivar;


    A simple model for the prediction of asphaltene precipitation is proposed. The model is based on an equation of state and uses standard thermodynamics, thus assuming that the precipitation phenomenon is a reversible process. The solid phase is treated as an ideal multicomponent mixture. An activi...

  7. Aggregation of model asphaltenes: a molecular dynamics study.

    Costa, J L L F S; Simionesie, D; Zhang, Z J; Mulheran, P A


    Natural asphaltenes are defined as polyaromatic compounds whose chemical composition and structure are dependent on their geological origin and production history, hence are regarded as complex molecules with aromatic cores and aliphatic tails that occur in the heaviest fraction of crude oil. The aggregation of asphaltenes presents a range of technical challenges to the production and processing of oil. In this work we study the behaviour of the model asphaltene-like molecule hexa-tert-butylhexa-peri-hexabenzocoronene (HTBHBC) using molecular dynamics simulation. It was found that the regular arrangement of the tert-butyl side chains prevents the formation of strongly-bound dimers by severely restricting the configurational space of the aggregation pathway. In contrast, a modified molecule with only 3 side chains is readily able to form dimers. This work therefore confirms the influence of the molecular structure of polyaromatic compounds on their aggregation mechanism, and reveals the unexpected design rules required for model systems that can mimic the behavior of asphaltenes. PMID:27465036

  8. Microfluidic investigation of the deposition of asphaltenes in porous media.

    Hu, Chuntian; Morris, James E; Hartman, Ryan L


    The deposition of asphaltenes in porous media, an important problem in science and macromolecular engineering, was for the first time investigated in a transparent packed-bed microreactor (μPBR) with online analytics to generate high-throughput information. Residence time distributions of the μPBR before and after loading with ~29 μm quartz particles were measured using inline UV-Vis spectroscopy. Stable packings of quartz particles with porosity of ~40% and permeability of ~500 mD were obtained. The presence of the packing materials reduced dispersion under the same velocity via estimation of dispersion coefficients and the Bodenstein number. Reynolds number was observed to influence the asphaltene deposition mechanism. For larger Reynolds numbers, mechanical entrapment likely resulted in significant pressure drops for less pore volumes injected and less mass of asphaltenes being retained under the same maximum dimensionless pressure drop. The innovation of packed-bed microfluidics for investigations on asphaltene deposition mechanisms could contribute to society by bridging macromolecular science with microsystems. PMID:24777527

  9. A Thermodynamic Mixed-Solid Asphaltene Precipitation Model

    Lindeloff, Niels; Heidemann, R.A.; Andersen, Simon Ivar; Stenby, Erling Halfdan

    A simple model for the prediction of asphaltene precipitation is proposed. The model is based on an equation of state and uses standard thermodynamics, thus assuming that the precipitation phenomenon is a reversible process. The solid phase is treated as an ideal multicomponent mixture. An activity...

  10. Water-in-Hydrocarbon Emulsions Stabilized by Asphaltenes at Low Concentrations.

    Yarranton; Hussein; Masliyah


    The role of Athabasca asphaltene particles and molecules in stabilizing emulsions was examined by measuring the surface area of water-in-toluene/hexane emulsions stabilized by various asphaltene fractions, each with a different proportion of soluble and insoluble asphaltenes. The stabilized interfacial area was found to depend only on the amount of soluble asphaltenes. Furthermore, the amount of asphaltenes on the interface was consistent with molecular monolayer coverage. Hence, at low concentrations, asphaltenes appear to both act as a molecular surfactant and stabilize emulsions. The effect of the hexane : toluene ratio on emulsion stability was examined as well. At lower hexane : toluene ratios, more asphaltenes were soluble but the surface activity of a given asphaltene molecule was reduced. The two effects oppose each other but, in general, a smaller fraction of asphaltenes appeared to stabilize emulsions at lower hexane : toluene ratios. The results imply that the emulsifying capacity of asphaltenes is reduced but not eliminated in better solvents. Copyright 2000 Academic Press. PMID:10882493

  11. Permeability reduction by asphaltenes and resins deposition in porous media

    R. Hamadou; M. Khodja; M. Kartout; A. Jada [Sonatrach/Division Centre de Recherche et Developpement, Boumerdes (Algeria)


    The deposition of crude oil polar fractions such as asphaltenes and resins in oil reservoir rocks reduce considerably the rock permeability and the oil production. In the present work, a crude oil and various core samples were extracted from Rhourd-Nouss (RN) reservoir rock. Afterwards, core flow experiments were carried out in the laboratory to investigate permeability reduction that causes formation damage. The core permeability damage was evaluated by flooding Soltrol, through the sample and measuring the solvent permeabilities, K{sub I} and K{sub f}, respectively, before and after injection of a given pore volume number of the crude oil. The data indicate that upon flooding the crude oil through the porous medium, considerable permeability reduction, expressed as the ratio (K{sub I} - K{sub f})/K{sub I}, and ranging from 72.4% to 98.3% were observed. The permeability reduction is found to result from irreversible retention of asphaltenes and resins in the porous core sample. However, no correlations could be established between the depth of the well, the core porosity, the core mineral compositions determined by X-ray analysis, and the permeability damage factors. In addition, effluents flowing away from RN wells were collected and analysed at various periods, after carrying out aromatic solvents squeezes. The amount of saturates, aromatics, resins, and asphaltenes (SARA analysis), of the crude oil, the deposited crude oil fraction, and the effluent's residues were measured and compared. The asphaltenes weight percent was found to increase from 1.56% for the crude oil to 11.42% for the deposited oil fraction, and was in the range 1.37-2.36% for the effluent's residues. Such results indicate that the deposited oil fraction and the effluent's residues consist mainly of asphaltenes and resins. 26 refs., 1 fig., 11 tabs.

  12. The importance of asphaltene origin on its behaviour in production systems

    Grutters, M.; Stankiewicz, A.; Cornelisse, P.; Utech, N. [Shell Global Solutions, The Hague (Netherlands)


    Despite much progress in characterizing asphaltenes, little is known about the relation between the size and shape of asphaltenes and their impact on flow assurance. This lack of understanding is related primarily to the fact that the asphaltenes structure found in crudes depends on many geochemical processes that are generally not included as input for flow assurance studies. The geochemical processes that are important to asphaltenes are type of source rock and deposited organic matter, maturity, migration history, and processes in the reservoir as hybridization and biodegradation. A careful examination of geochemical processes can reveal the relationship between asphaltene behaviour in fields that are seemingly very different or distant. This paper provided some examples of these relationships. Understanding the structure of asphaltenes is critical and warrants the further development of methods for more accurate characterization.

  13. Method for determining asphaltene stability of a hydrocarbon-containing material

    Schabron, John F; Rovani, Jr., Joseph F


    A method for determining asphaltene stability in a hydrocarbon-containing material having solvated asphaltenes therein is disclosed. In at least one embodiment, it involves the steps of: (a) precipitating an amount of the asphaltenes from a liquid sample of the hydrocarbon-containing material with an alkane mobile phase solvent in a column; (b) dissolving a first amount and a second amount of the precipitated asphaltenes by changing the alkane mobile phase solvent to a final mobile phase solvent having a solubility parameter that is higher than the alkane mobile phase solvent; (c) monitoring the concentration of eluted fractions from the column; (d) creating a solubility profile of the dissolved asphaltenes in the hydrocarbon-containing material; and (e) determining one or more asphaltene stability parameters of the hydrocarbon-containing material.

  14. Prediction of the Gas Injection Effect on the Asphaltene Phase Envelope

    Bahrami Peyman; Kharrat Riyaz; Mahdavi Sedigheh; Firoozinia Hamed


    Asphaltene instability may occur when pressure, temperature and compositional variations affect the reservoir oil. Permeability reduction, wettability alteration, and plugging of wells and flow lines are the consequences of this phenomenon. Therefore, it is crucial to investigate the asphaltene behavior in different thermodynamic conditions by knowing the Asphaltene Precipitation Envelope (APE) in a preventive way rather than the costly clean-up procedures. The selected reservoir oil has face...

  15. Bayesian Belief Network Method for Predicting Asphaltene Precipitation in Light Oil Reservoirs

    Jeffrey O. Oseh (M.Sc.); Olugbenga A. Falode (Ph.D)


    Asphaltene precipitation is caused by a number of factors including changes in pressure, temperature, and composition. The two most prevalent causes of asphaltene precipitation in light oil reservoirs are decreasing pressure and mixing oil with injected solvent in improved oil recovery processes. This study focused on predicting the amount of asphaltene precipitation with increasing Gas-Oil Ratio in a light oil reservoir using Bayesian Belief Network Method. These Artificial Intelligence-Baye...

  16. Impact of maltene and asphaltene fraction on mechanical behavior and microstructure of bitumen

    Hofko, B.; L. Eberhardsteiner; Fussl, J.; H. Grothe; Handle, F.; Hospodka, M.; Grossegger, D.; Nahar, S.N.; Schmets, A. J. M.; Scarpas, A.


    As a widely accepted concept, bitumen consists of four fractions that can be distinguished by their polarity. Highly polar asphaltene micelles are dispersed in a viscous phase of saturates, aromatics and resins (maltene phase). Different concentrations of asphaltenes in the bitumen result in a range of mechanical response properties. In an interdisciplinary study the impact of the maltene phase and asphaltenes on the linear viscoelastic behavior and the microstructure of bitumen were analyzed...


    Silas R. Ferreira


    Full Text Available 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 from refineries. However, due to the diversity and complexity of these structures, there is still much to be investigated. In this study, asphaltene (subfractions were extracted from an asphaltic residue (AR02, characterized by NMR, elemental analysis, X-ray fluorescence and MS-TOF, and compared to asphaltene subfractions obtained from another asphaltic residue (AR01 described in a previous article. The (subfractions obtained from the two residues were used to prepare model-systems containing 1 wt% of asphaltenes in toluene and their phase behavior was evaluated by measuring asphaltene precipitation onset using optical microscopy. The results obtained indicated minor differences between the asphaltene fractions obtained from the asphaltic residues of distinct origins, with respect to aromaticity, elemental composition (CHN, presence and content of heteroelements and average molar mass. Regarding stability, minor differences in molecule polarity appear to promote major differences in the phase behavior of each of the asphaltene fractions isolated.

  18. The acoustic spectroscopy of asphaltene aggregation in petroleum

    A sphaltenes are well known to be important in causing blockages during production, transportation and refining. They are also responsible for the formation of tar mats in petroleum reservoirs, which can impede crude oil recovery. Acoustic spectroscopy in the frequency range 2 – 120 MHz was used to detect the aggregation of asphaltenes in a North Sea crude oil (UK continental shelf). In the absence of aggregation, both the toluene solvent and the maltenes isolated from the oil exhibit a power law dependence which is a function of the continuous phase. In contrast the crude oil itself showed clear signs of a changing size of the scattering entities. With sufficient information, it may in future be possible to determine the size of the scattering particles from the acoustic spectrum including the changing size of the asphaltene particles during aggregation.

  19. Asphaltenes in Mexican fuel oils; Asfaltenos en combustoleos mexicanos

    Longoria Ramirez, Rigoberto [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)


    In this article the main aspects in which the Instituto de Investigaciones Electricas (IIE) has worked to contribute to the solution of problems due to the presence of asphaltenes in national fuel oils, are emphasized. The increment of these compounds, that concentrate harmful elements, in the last ten years has reached 22% by weight of the fuel oil. It is demonstrated that the quantification of asphaltenes depends on the type of solvent employed. [Espanol] En este articulo se subrayan los principales aspectos en los que el Instituto de Investigaciones Electricas (IIE) ha trabajado para contribuir a la solucion de problemas debidos a la presencia de asfaltenos en combustoleos nacionales. El incremento de estos compuestos, que concentran elementos nocivos, en los ultimos diez anos ha llegado hasta un 22% del peso del combustoleo. Se demuestra que la cuantificacion de los asfaltenos depende del tipo de solvente utilizado.

  20. Cooee bitumen II: Stability of linear asphaltene nanoaggregates

    Lemarchand, Claire,; Schrøder, Thomas; Dyre, J.C.; Hansen, Jesper Schmidt


    Asphaltene and smaller aromatic molecules tend to form linear nanoaggregates in bitumen. Over the years bitumen undergoes chemical aging and during this process, the size of the nanoaggregate increases. This increase is associated with an increase in viscosity and brittleness of the bitumen, eventually leading to road deterioration. This paper focuses on understanding the mechanisms behind nanoaggregate size and stability. We used molecular dynamics simulations to quantify the probability of ...

  1. Behavior of asphaltene model compounds at w/o interfaces.

    Nordgård, Erland L; Sørland, Geir; Sjöblom, Johan


    Asphaltenes, present in significant amounts in heavy crude oil, contains subfractions capable of stabilizing water-in-oil emulsions. Still, the composition of these subfractions is not known in detail, and the actual mechanism behind emulsion stability is dependent on perceived interfacial concentrations and compositions. This study aims at utilizing polyaromatic surfactants which contains an acidic moiety as model compounds for the surface-active subfraction of asphaltenes. A modified pulse-field gradient (PFG) NMR method has been used to study droplet sizes and stability of emulsions prepared with asphaltene model compounds. The method has been compared to the standard microscopy droplet counting method. Arithmetic and volumetric mean droplet sizes as a function of surfactant concentration and water content clearly showed that the interfacial area was dependent on the available surfactant at the emulsion interface. Adsorption of the model compounds onto hydrophilic silica has been investigated by UV depletion, and minor differences in the chemical structure of the model compounds caused significant differences in the affinity toward this highly polar surface. The cross-sectional areas obtained have been compared to areas from the surface-to-volume ratio found by NMR and gave similar results for one of the two model compounds. The mean molecular area for this compound suggested a tilted geometry of the aromatic core with respect to the interface, which has also been proposed for real asphaltenic samples. The film behavior was further investigated using a liquid-liquid Langmuir trough supporting the ability to form stable interfacial films. This study supports that acidic, or strong hydrogen-bonding fractions, can promote stable water-in-oil emulsion. The use of model compounds opens up for studying emulsion behavior and demulsifier efficiency based on true interfacial concentrations rather than perceived interfaces. PMID:19852481

  2. Influence of asphaltene aggregation and pressure on crude oil emulsion stability

    Auflem, Inge Harald


    Water-in-crude oil emulsions stabilised by various surface-active components are one of the major problems in relation to petroleum production. This thesis presents results from high-pressure separation experiments on ''live'' crude oil and model oil emulsions, as well as studies of Interactions between various indigenous stabilising materials in crude oil. A high-pressure separation rig was used to study the influence of gas and gas bubbles on the separation of water-in-crude oil emulsions. The results were interpreted as a flotation effect from rising gas bubbles, which led to increased separation efficiency. The separation properties of a ''live'' crude oil were compared to crude oil samples recombined with various gases. The results showed that water-in-oil emulsions produced from the ''live'' crude oil samples, generally separated faster and more complete, than emulsions based on recombined samples of the same crude oil. Adsorption of asphaltenes and resins onto a hydrophilic surface from solutions with varying aromatic/aliphatic character was investigated by a quarts crystal microbalance. The results showed that asphaltenes adsorbed to a larger degree than the resins. The resins were unable to desorb pre-adsorbed asphaltenes from the surface, and neither did they adsorb onto the asphaltene-coated surface. In solutions of both of resins and asphaltenes the two constituents associated in bulk liquid and adsorbed to the surface in the form of mixed aggregates. Near infrared spectroscopy and pulsed field gradient spin echo nuclear magnetic resonance were used to study asphaltene aggregation and the influence of various amphiphiles on the asphaltene aggregate size. The results showed Interactions between the asphaltenes and various chemicals, which were proposed to be due to acid-base interactions. Among the chemicals used were various naphthenic acids. Synthesised monodisperse acids gave a reduction of

  3. Enhancing the Effectiveness of Carbon Dioxide Flooding by Managing Asphaltene Precipitation

    Deo, Milind D.


    This project was undertaken to understand fundamental aspects of carbon dioxide (CO2) induced asphaltene precipitation. Oil and asphaltene samples from the Rangely field in Colorado were used for most of the project. The project consisted of pure component and high-pressure, thermodynamic experiments, thermodynamic modeling, kinetic experiments and modeling, targeted corefloods and compositional modeling.

  4. Molecular dynamic simulation of asphaltene co-aggregation with humic acid during oil spill.

    Zhu, Xinzhe; Chen, Daoyi; Wu, Guozhong


    Humic acid in water and sediment plays a key role in the fate and transport of the spilled oil, but little is known about its influence on the aggregation of heavy oil asphaltenes which is adverse for remediation. Molecular dynamic simulation was performed to characterize the co-aggregation of asphaltenes (continental model and Violanthrone-79 model) with Leonardite humic acid (LHA) at the toluene-water interface and in bulk water, respectively, to simulate the transport of asphaltenes from oil to water. At the toluene-water interface, a LHA layer tended to form and bind to the water by hydrogen bonding which provided a surface for the accumulation of asphaltenes by parallel or T-shape stacking. After entering the bulk water, asphaltene aggregates stacked in parallel were tightly sequestrated inside the inner cavity of LHA aggregates following surface adsorption and structure deformation. Asphaltene aggregation in water was 2-fold higher than at the toluene-water interface. The presence of LHA increased the intensity of asphaltene aggregation by up to 83% in bulk water while relatively less influence was observed at the toluene-water interface. Overall results suggested that the co-aggregation of asphaltene with humic acid should be incorporated to the current oil spill models for better interpreting the overall environmental risks of oil spill. PMID:26149857

  5. 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 reactions using dodecylbenzene sulfonic acid (DBSA) to increase their lipophilicity. Nanoparticle synthesis was performed using the co-precipitation method followed by annealing of these nanoparticles, aiming to change the structural phase. Modified and unmodified nanoparticles were tested by FTIR-ATR, XRD and TGA/DTA. In addition, precipitation onset of the asphaltenes was performed using modified and unmodified nanoparticles. These tests showed that modified nanoparticles have a potential application as flocculant agents used to remove asphaltenes before oil refining, since the presence of nanoparticles promotes the asphaltene precipitation onset with the addition of a small amount of non-solvent (author)

  6. An experimental study of asphaltene particle sizes in n-heptane-toluene mixtures by light scattering

    Rajagopal K.


    Full Text Available The particle size of asphaltene flocculates has been the subject of many recent studies because of its importance in the control of deposition in petroleum production and processing. We measured the size of asphaltene flocculates in toluene and toluene - n-heptane mixtures, using the light-scattering technique. The asphaltenes had been extracted from Brazilian oil from the Campos Basin, according to British Standards Method IP-143/82. The asphaltene concentration in solution ranged between 10-6 g/ml and 10-7 g/ml. Sizes was measured for a period of about 10000 minutes at a constant temperature of 20°C. We found that the average size of the particles remained constant with time and increase with an increase in amount of n-heptane. The correlation obtained for size with concentration will be useful in asphaltene precipitation models.

  7. The formation of rag layers and the role of interfacial partition of naphthenates and asphaltenes

    Moran, K. [Syncrude, Edmonton, AB (Canada); Kiran, S.; Acosta, E.J. [Toronto Univ., ON (Canada). Dept. of Chemical Engineering and Applied Chemistry


    Stable emulsions of oil and water are known as rag layers and have been associated with the precipitation of asphaltenes and the formation of liquid crystal phases. This paper presented optical microscopy studies of rag layers produced under different conditions. Liquid crystal formation was observed only under specific conditions, such as in the presence of un-dissociated naphthenic acids. Liquid crystal phases were not observed in the absence of naphthenic acids or in the presence of sodium naphthenates. The formation of rag layer was associated to the fraction of asphaltene where the oil was reduced. Optical micrographs showed that the droplets of oil and/or water in the rag layer were not stabilized by the particles of asphaltene precipitated. These observations were explained using a hypothesis of asphaltene interfacial partition, whereby the asphaltene molecules accumulate near the oil/water interface to form skins that inhibit their coalescence and separation.

  8. Chemical modification of cobalt ferrite nanoparticles with possible application as asphaltene flocculant agent

    Oliveira, G.E.; Clarindo, J.E.S.; Santo, K.S.E., E-mail: [Universidade Federal do Espirito Santo (CCE/DQUI/UFES), Vitoria, ES (Brazil). Centro de Ciencias Exatas. Dept. de Quimica; Souza Junior, F.G. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), Rio de Janeiro, RJ (Brazil). Instituto de Macromoleculas


    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 reactions using dodecylbenzene sulfonic acid (DBSA) to increase their lipophilicity. Nanoparticle synthesis was performed using the co-precipitation method followed by annealing of these nanoparticles, aiming to change the structural phase. Modified and unmodified nanoparticles were tested by FTIR-ATR, XRD and TGA/DTA. In addition, precipitation onset of the asphaltenes was performed using modified and unmodified nanoparticles. These tests showed that modified nanoparticles have a potential application as flocculant agents used to remove asphaltenes before oil refining, since the presence of nanoparticles promotes the asphaltene precipitation onset with the addition of a small amount of non-solvent (author)

  9. Evaluation of the asphaltenes macromolecules stabilization by alkylbenzenes compounds; Avaliacao da estabilizacao de macromoleculas asfaltenicas por compostos alquilbenzenicos

    Oliveira, G.E.; Mansur, C.R.E.; Lucas, E.F. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas]. E-mail:;; Gonzalez, G. [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas]. E-mail:


    The asphaltene deposition is a problem that affects oil production, transportation and storage. Some researches about asphaltene stabilization have been made in order to avoid its flocculation and deposition. In this work, the performance of four alkylbenzene compounds as asphaltene stabilizer was evaluated. The additive were tested in two different concentrations: 5000 and 10000 mg/L. Cardanol, polycardanol, polystyrene and polystyrene sulfonade were used as additive. The study was carried out by asphaltene precipitation in a solvent mixture (toluene and heptane), since that the asphaltene solubility in these solvents are different. The best results were obtained by using cardanol, at 5000 mg/L. (author)

  10. Geochemistry of raw Asphaltenes of the Oriental Plains

    Were studied samples of asphaltenes previously separate from 44 raw (p.eb ≥ 200 Celsius degrades) of the three regions of the Oriental Plains: Meta, Casanare and Arauca. The elementary analysis of asphaltenes samples of was carried out in a Carlo Erba CHNS analyzing, with a Coulometric auxiliary of Sulfur (Western Atlas, Core Laboratories). Starting from this analysis the atomic relationships were calculated (H/C), (O/C), (N/S), (C/S) and (C/N) which were used to discriminate or to separate the samples in groups. The pyrolysis Rock-eval was carried out on 20 mg, of each sample diluted with 80 mg of fine quartz, in order to avoiding the problems that are presented when it works with samples that contain more than 20% of Total Organic Carbon (COT). The results of this pyrolysis allowed establishing the presence of six groups or families in the samples of asphaltenes. It was also proven that the raw of the Arauca Field is of terrestrial origin while those of Cano Limon are originated of marine kerogens. With Nuclear Magnetic Resonance of proton (RMN of H) the percentages of Ha, Hβ, Ha, Hox y HAR+F, were calculated as well as the percentage of carbon aromatic insubstituted (% CAR (US)). Also, it was calculated the Aromatic Factor, FA and the substitution degree a, they were also calculated starting from these data the relationships FA/s, Hα/Hox+F y Hα/Hβ. When correlating the diverse data obtained starting from the elementary analysis to each other, the pyrolysis rock-eval and the RMN of H was possible to find two families or groups of raw in each one of the three areas of the Oriental Plains, giving a total of six families or groups of raw in the 44 studied samples. The correlations were: S2/S3 versus (N/S)AT, (C/S)AT versus FA/a, % Car (US) versus FA/d, FA versus, Ha /Ha r+d versus F A/d. Keeping in mind that Behar et al (1984) they concluded in their investigation of asphalts Geochemistry that the gases chromatography (PY -GC) of asphalts it could be used for

  11. Characterization of Physically and Chemically Separated Athabasca Asphaltenes Using Small-Angle X-ray Scattering

    Amundaraín Hurtado, Jesús Leonardo; Chodakowski, Martin; Long, Bingwen; Shaw, John M. (Alberta)


    Athabasca asphaltenes were characterized using small-angle X-ray scattering (SAXS). Two methods were used to separate asphaltenes from the Athabasca bitumen: namely, chemical separation by precipitation with n-pentane and physical separation by nanofiltration using a zirconia membrane with a 20 nm average pore size. The permeate and chemically separated samples were diluted in 1-methylnaphtalene and n-dodecane prior to SAXS measurements. The temperature and asphaltene concentration ranges were 50-310 C and 1-10.4 wt %, respectively. Model-independent analysis of SAXS data provided the radius of gyration and the scattering coefficients. Model-dependent fits provided size distributions for asphaltenes assuming that they are dense and spherical. Model-independent analysis for physically and chemically separated asphaltenes showed significant differences in nominal size and structure, and the temperature dependence of structural properties. The results challenge the merits of using chemically separated asphaltene properties as a basis for asphaltene property prediction in hydrocarbon resources. While the residuals for model-dependent fits are small, the results are inconsistent with the structural parameters obtained from model-independent analysis.

  12. Study on the dipole moment of asphaltene molecules through dielectric measuring

    Zhang, Long Li


    The polarity of asphaltenes influences production, transportation, and refining of heavy oils. However, the dipole moment of asphaltene molecules is difficult to measure due to their complex composition and electromagnetic opaqueness. In this work, we present a convenient and efficient way to determine the dipole moment of asphaltene in solution by dielectric measurements alone without measurement of the refractive index. The dipole moment of n-heptane asphaltenes of Middle East atmospheric residue (MEAR) and Ta-He atmospheric residue (THAR) are measured within the temperature range of -60°C to 20°C. There is one dielectric loss peak in the measured solutions of the two types of asphaltene at the temperatures of -60°C or -40°C, indicating there is one type of dipole in the solution. Furthermore, there are two dielectric loss peaks in the measured solutions of the two kinds of asphaltene when the temperature rises above -5°C, indicating there are two types of dipoles corresponding to the two peaks. This phenomenon indicates that as the temperature increases above -5°C, the asphaltene molecules aggregate and present larger dipole moment values. The dipole moments of MEAR C7-asphaltene aggregates are up to 5 times larger than those before aggregation. On the other hand, the dipole moments of the THAR C7-asphaltene aggregates are only 3 times larger than those before aggregation. It will be demonstrated that this method is capable of simultaneously measuring multi dipoles in one solution, instead of obtaining only the mean dipole moment. In addition, this method can be used with a wide range of concentrations and temperatures.

  13. Diagnosis of asphaltene stability in crude oil through “two parameters” SVM model

    Chamkalani, Ali; Mohammadi, Amir H.; Eslamimanesh, Ali;


    Asphaltene precipitation/deposition and its imposing difficulties are drastic issues in petroleum industry. Monitoring the asphaltene stability conditions in crude oil systems is still a challenge and has been subject of many studies. In this work, the Refractive Index (RI) of several oil samples...... is determined using the existing SARA fractions experimental data for this purpose. The powerful Least-Square modification of Support Vector Machine (LSSVM) strategy is applied to develop a computer program, by which the asphaltene stability region can be determined for various crudes. The developed two...

  14. Investigating molecular interactions and surface morphology of wax-doped asphaltenes.

    Pahlavan, Farideh; Mousavi, Masoumeh; Hung, Albert; Fini, Ellie H


    The nature and origin of bee-like microstructures (bees) in asphalt binders and their impact on asphalt oxidation have been the subject of extensive discussions in recent years. While several studies refer to the bees as solely surface features, some others consider them to be bulk microcrystalline components that are formed due to co-precipitation of wax and asphaltene molecules. In this study, we use a rigorous theoretical and experimental approach to investigate the interplay of asphalt components (mainly asphaltene and wax) and their impact on bee formation. In the theoretical section, quantum-mechanical calculations using density functional theory (DFT) are used to evaluate the strength of interactions between asphaltene unit sheets in the presence and absence of a wax component, as well as the mutual interactions between asphaltene molecules (monomers and dimers) and paraffin wax. The results of this section reveal that paraffin waxes not only do not reinforce the interaction between the asphaltene unit sheets, they destabilize asphaltene assembly and dimerization. AIM (Atom in Molecules) analysis shows the destabilizing effect of wax on asphaltene assembly as a reduction in the number of cage and bond critical points between asphaltenes. This destabilization effect among interacting systems (asphaltene-asphaltene and wax-asphaltene) does not support the hypothesis that interaction between paraffin waxes and non-wax components, such as asphaltene, is responsible for their co-precipitation and bee formation. To further examine the effect of wax component on asphalt microstructure experimentally, we used atomic force microscopy (AFM) to study the surface morphology of an asphalt sample doped with 1% to 25% paraffin wax. In agreement with the conclusions drawn from the DFT approach, our experiments indicate that paraffin wax tends to crystallize separately and form lamellar paraffin wax crystal inclusions with 10 nm thickness. Moreover, the addition of 3% wax

  15. Enhancing the Effectiveness of Carbon Dioxide Flooding by Managing Asphaltene Precipitation

    Deo, Milind D.


    Objectives of this project was to understand asphaltene precipitation in General and carbon dioxide induced precipitation in particular. To this effect, thermodynamic and kinetic experiments with the Rangely crude oil were conducted and thermodynamic and reservoir models were developed.

  16. Asphaltene self-association: Modeling and effect of fractionation with a polar solvent

    Garcia, Daniel Merino; Murgich, J; Andersen, Simon Ivar


    The self-association of asphaltenes in toluene is believed to occur step-wise, rather than by the formation of micelles. A number of step-wise models have been used to fit the calorimetric titration of asphaltenes in dried toluene solutions, with excellent results. All the models are based on...... chemical reactions equivalent to the ones found in polymerization. The study shows that the choice of the average properties of asphaltenes, such as the molecular weight, is critical in the final value of the parameter of interest, namely the average heat of self-association DeltaH(a). The low values of...... because it does not self-associate or because the dilution effect is not strong enough to break the aggregates. Fluorescence and IR spectroscopy experiments confirm there is self-association in INS fraction, leading to the conclusion that asphaltene aggregates are formed by bonds of different strengths...

  17. Modelling asphaltene precipitation equilibrium : influence of the experimental contact time and temperature

    Dufour, J.; Marugan, J.; Calles, J.A.; Gimenez-Aguirre, R. [Rey Juan Carlos Univ., Madrid (Spain). Dept. of Chemical and Environmental Technology, Repsol-YPF Flow Assurance Laboratory; Pena, J.L. [Rey Juan Carlos Univ., Madrid (Spain). Dept. of Chemical and Environmental Technology, Repsol-YPF Flow Assurance Laboratory; Centro Tecnologico Repsol-YPF, Madrid (Spain); Merino-Garcia, D. [Centro Tecnologico Repsol-YPF, Madrid (Spain)


    Asphaltene deposition creates flow assurance problems and economic losses for petroleum companies. Predictive models are therefore needed to prevent these problems. Most models found in the literature are based on equilibrium calculations and must be checked against experimental data of both onset and amount of asphaltenes separated. However, the samples must be equilibrated for a long time since the kinetics of asphaltene aggregation and precipitation are slow. This paper discussed the kinetics of asphaltene precipitation, based on results obtained from a problematic South American crude and its residue. The influence of temperature, chain length of the n-alkane solvent and n-alkane/oil mass ratio was evaluated. The solids were characterized by 1H NMR, elemental analysis and Fourier transform infrared (FTIR) spectroscopy to determine their chemical structure. Metal contents (mainly Fe, V and Ni) have been measured by atomic emission spectroscopy. The true equilibrium data will be used to validate equilibrium models from the literature.

  18. Bayesian Belief Network Method for Predicting Asphaltene Precipitation in Light Oil Reservoirs

    Jeffrey O. Oseh (M.Sc.


    Full Text Available Asphaltene precipitation is caused by a number of factors including changes in pressure, temperature, and composition. The two most prevalent causes of asphaltene precipitation in light oil reservoirs are decreasing pressure and mixing oil with injected solvent in improved oil recovery processes. This study focused on predicting the amount of asphaltene precipitation with increasing Gas-Oil Ratio in a light oil reservoir using Bayesian Belief Network Method. These Artificial Intelligence-Bayesian Belief Network Method employed were validated and tested by unseen data to determine their accuracy and trend stability and were also compared with the findings obtained from Scaling equations. The obtained Bayesian Belief Network results indicated that the method showed an improved performance of predicting the amount of asphaltene precipitated in light oil reservoirs thus reducing the number of experiments required.

  19. Studies of water-in-oil emulsions: the role of asphaltenes and resins

    Experiments were conducted to study the role of asphaltenes in water-in-oil emulsions. Asphaltenes are the agents that act like surfactants and are responsible for the formation and stability of these emulsions. Experiments were conducted on an emulsion that had been standing for three months, and on a salt water-oil emulsion. A series of tests were performed to study how asphaltenes would migrate in the absence of a strong gravity effect. All the experiments showed that asphaltenes migrate to the oil-water interface from the oil. This explains why an emulsion which sits for a long time can become more viscous and more stable as time progresses. Future work will determine whether resins will behave in the same manner. 36 refs., 2 tabs

  20. Investigation of asphaltene precipitation in miscible gas injection processes: experimental study and modeling

    S. Moradi


    Full Text Available Asphaltene precipitation during natural depletion and miscible gas injection is a common problem in oilfields throughout the world. In this work, static precipitation tests are conducted to investigate the effects of pressure, temperature and gas type and concentration on asphaltene instability. Three different oil samples have been studied under reservoir conditions with/without nitrogen and methane injection. Besides applying common thermodynamic models, a new scaling equation is presented to predict asphaltene precipitation under HPHT gas injection. Extensive published data from the literature are also used in model development. The scaling approach is attractive because it is simple and complex asphaltene properties are not involved in the calculations. Moreover, the proposed model provides universal parameters for different fluid samples over a wide range of pressure and temperature that makes it novel for evaluation of future gas injection projects when simple PVT data are available.

  1. Analysis of metals in asphaltenes of KU-46 by PIXE analysis

    The content of metals of the asphaltenes obtained from the KU-46 mexican crude with n-heptane was evaluated. The found metals in higher concentration are transition metals as well as the vanadium, nickel, copper and zinc. Moreover the sulfur in high concentrations was quantified. The metallic content of the asphaltenes revealed that the crude contains a lower quantity of metals unlike the vacuum residue previously analysed. (Author)

  2. Prediction of the Gas Injection Effect on the Asphaltene Phase Envelope

    Bahrami Peyman


    Full Text Available Asphaltene instability may occur when pressure, temperature and compositional variations affect the reservoir oil. Permeability reduction, wettability alteration, and plugging of wells and flow lines are the consequences of this phenomenon. Therefore, it is crucial to investigate the asphaltene behavior in different thermodynamic conditions by knowing the Asphaltene Precipitation Envelope (APE in a preventive way rather than the costly clean-up procedures. The selected reservoir oil has faced a remarkable decline in production due to several years of extraction, and Enhanced Oil Recovery (EOR has been considered as a solution. Therefore, in this paper, a comprehensive study was carried out to predict the effects of different injected gases on asphaltene onset and to prevent future asphaltene precipitation based on the laboratory data. The Advanced Redlich-Kwong-Soave (RKSA equation of state was considered to develop APE using Multiflash (Infochem Co.. For the selected reservoir oil, with temperature reduction at low temperatures, asphaltene precipitation weakened and made the onset pressure decrease, so this behavior is different from the results obtained in other published reports. On the basis of this model, several sensitivity analyses were performed with different gases (i.e., methane, CO2, N2 and associated gases to compare the risk of each gas for future EOR strategies. APE tend to expand as the amount of injected gases increases, except for CO2 gas injection, that showed another unconventional behavior for this crude oil. It was observed that for CO2 gas injection below a certain temperature, asphaltene stability increased, which can be considered as a good inhibitor of asphaltene precipitation.

  3. Distribution of metals in vacuum residuums, asphaltenes and maltenes by PIXE

    The PIXE technique for determining directly the distribution and abundance of trace metals in vacuum residuum, asphaltenes and maltenes separated with n-alkanes (C5-C8) is used. The metal content of petroleum derivatives revealed that the vacuum residuum contains iron, aluminium, vanadium and nickel mainly, while that the asphaltenes and maltenes maintain inside of their composition only preferably the vanadium and nickel as majority elements. (Author)

  4. Kinetic studies on the pyrolysis of asphaltenes from differenttypes of kerogens


    The pyrolysis kinetics of a series of asphaltenes, from different types of kerogens, are studied in this work. The results indicate that the distributions of activation energy are over a wide range for the asphaltenes from type I kerogens. There is still a large potential of hydrocarbon generation in case the activation energy is above 350 kJ·mol-1. While the distributions of activation energy are comparatively over a narrow range for the asphaltenes from type II and II kerogens,there is a little or almost no potential of hydrocarbon generation with the activation energy above 350 kJ·mol-1 respectively. For the asphaltenes from some specific type of kerogens, the pyrolysis kinetics can be applied to marking their maturity. Furthermore, based on detailed discussions of the kinetics parameter frequency factor, the asphaltenes from type I kerogens are considered to be of great potential to regenerate oils, while the asphaltenes' potential for oil-to-gas conversion tends to go down in order of primitive kerogen types of Ⅲ II and I.

  5. Structural Characterisation of Asphaltenes during Residue Hydrotreatment with Light Cycle Oil as an Additive

    Yong-Jun Liu


    Full Text Available Several atmospheric residues (AR of Kuwaiti crude, in the absence, or in the presence, of light cycle oil (LCO as an aromatic additive, were hydrotreated in an experimental plant. Asphaltenes (precipitated from Kuwaiti AR, a hydrotreated AR, and a hydrotreated blend of AR and LCO were characterised by chemical structure and changes during residue hydrotreatment. The average structural parameters of these asphaltenes, obtained from a combined method of element analysis, average molecular weight, X-ray diffraction, and NMR, demonstrate that, after hydrotreatment, the aromatic cores of the asphaltenes become more compact and smaller whereas the peripheral alkyl branches are decreased in number and shortened. The influence of LCO on residue hydrotreating is also studied in terms of structural changes in the asphaltenes. The findings imply that LCO added to AR during hydrotreating improves the degree of aromatic substitution, the total hydrogen/carbon atomic ratio per average molecule, the distance between aromatic sheets and aliphatic chains, and so forth, by modifying the colloidal nature and microstructure of asphaltene: this is beneficial for the further hydroprocessing of AR. Three hypothetical average molecules are proposed to represent the changes undergone by such asphaltenes during hydrotreatment as well as the effects of additive LCO.

  6. Asphaltene macrostructure of petroleum crude investigated by small angle neutron scattering

    Complete text of publication follows. The amount and the phase stability of the asphaltene fraction in petroleum and crude oils are important during the production, the processing and the transportation of these crude fluids. Small angle neutron scattering SANS technique was used to investigate the colloidal properties of an Algerian petroleum crude. Dilute samples with various concentrations up to 11% vol. were studied. The macrostructure of the present asphaltene fraction as well as its size distributions and volume fraction were extracted by modeling the experimental scattering data using a non linear least squares fitting program. The analysis results suggest that into the studied conditions, the petroleum crude asphaltene fraction seems to form stable micellar systems with a polydisperse globular like shape structures. It was found that the micelles mean size radius was about 2 nm and did not vary with the petroleum fluid medium concentration. The volume fraction of asphaltenes did not also increase with petroleum fluid medium concentration. These results suggest that the forming micelles were stable and there was no aggregation. In order to probe the internal structure of the asphaltene micelles the contrast variation technique was also performed on the isolated asphaltene fraction and from these results a form factor shape model was proposed. (author)

  7. Formation of asphaltene deposits from crude oil destabilized by addition of propane

    Wang, J.; Creek, J. [Chevron Energy Technology Co., Houston, TX (United States); Fan, T.; Buckley, J. [New Mexico Inst. of Mining and Technology, NM (United States)


    As oil development moves into deeper water and deeper wells, it is increasingly important to predict the formation of asphaltene deposits. The first step toward predicting deposition is knowing the asphaltene stability as a function of temperature, pressure, and composition. Flocculated asphaltenes can segregate under the influence of gravity in low energy environments. The challenge lies in understanding the deposits that form on pipe walls in producing wells. This paper reported on a continuing study of arterial deposition from destabilized crude oils in stainless steel capillary tubing as a function of several variables, including the molecular size of the paraffinic precipitating agent. The initial studies revealed that destabilization of asphaltenes from a given crude oil with higher molecular weight precipitants produced a larger volume of asphaltene enriched deposit compared to a lower molecular weight precipitant with the same crude oil. Liquid n-paraffins precipitants from n-pentane to n-pentadecane were used in the initial studies. The data was then used to forecast precipitation with solution gas at different pressures and temperatures. In this present study, the range of paraffinic precipitants was extended to include propane for a comparative evaluation to determine the driving force for asphaltene precipitation in reservoir fluids.

  8. Chemistry and structure of coal derived asphaltenes and preasphaltenes. Interim report

    Yen, T. F.


    It is the objective of this project to isolate the asphaltene and preasphaltene fractions from coal liquids from a number of liquefaction processes. These processes consist of in general: catalytic hydrogenation, staged pyrolysis and solvent refining. The asphaltene fractions may be further separated by both gradient elution through column chromatography, and molecular size distribution through gel permeation chromatography. These coal-derived asphaltene and preashpaltene fractions will then be investigated by various chemical and physical methods for characterization of their structures. After the parameters are obtained, these parameters will be correlated with the refining and conversion variables which control a given type of liquefaction process. The effects of asphaltene in catalysis, ash or metal removal, desulfurization and denitrification will also be correlated. It is anticipated that understanding the role of asphaltenes in liquefaction processes will enable engineers to both improve existing processes, and to make recommendations for operational changes in planned liquefaction units. The objective of Phase 1 was to complete the isolation and separation of coal liquid fractions and to initiate their characterization. The objective of Phase 2 is to continue the characterization of coal asphaltenes and other coal liquid fractions by use of physical and instrumental methods. The structural parameters obtained will be used to postulate hypothetical average structures for coal liquid fractions.The objective of Phase 3 is to concentrate on the characterization of the preasphaltene (benzene insoluble fraction) of coal liquid fraction by the available physical and chemical methods to obtain a number of structural parameters.


    Silas R. Ferreira; Fabio R. Barreira; Luciana S. Spinelli; Katia Z. Leal; Peter Seidl; Elizabete F. Lucas


    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 from refineries. However, due to the diversity and complexity of these structures, there is still much to be investigated. In this study,...

  10. Study on the interaction of asphaltenes macromolecules and stabilizer compounds: LCC and cardanol; Estudo da interatividade entre macromoleculas asfaltenicas e compostos estabilizantes: LCC e cardanol

    Moreira, Luiz Fernando Bandeira; Lucas, Elizabete Fernandes [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Macromoleculas; Gonzalez, Gaspar [PETROBRAS, Rio de Janeiro, RJ (Brazil). Centro de Pesquisas


    Petroleum contains asphaltene which can be precipitated, generating various problems affecting the crude oil production and transport, storage and processing. This work presents a mathematical adaptation of interaction models for the asphaltene-stabilizer system allowing prediction of stabilizer performance for avoiding asphaltene precipitation. The ashew liquid and particularly the cardanol have been studied by using the peptising test. The ashew and cardanol present the asphaltene stabilizer properties and positive properties in both cases. (author)

  11. Determination of trace elements in GPC fractions of oil-sand asphaltenes by INAA

    Asphaltene samples precipitated from Athabasca and Cold Lake oil-sand bitumens were separated into 12 fractions of varying molecular weight by preparative gel permeation chromatography (GPC). Each fraction was then analyzed by analytical GPC and visible spectrometry. Concentrations of As, Ce, Co, Cr, Eu, Ga, Hf, Hg, La, Ni, Sb, Sc, Se, Sm, Tb, Th, U, V, Zn, and Zr in the fractions were determined by neutron activation analysis. Molecular weights of the Athabasca fractions are generally higher than the corresponding Cold Lake fractions. Between 58% and 90% of the metal contents occur in the high molecular weight fractions of both asphaltenes. Except for V and Cr, which show biomodel distributions, all the elements have decreasing concentrations as the molecular weight of the fraction decreases. High molecular weight fractions, constituting about 55% of the whole asphaltenes, contain nonporphyrin bound vanadium compounds. It is estimated that 27% and 31% of V present in Athabasca and Cold Lake asphaltenes respectively occur as porphyrin type compounds, including vanadyl prophyrins released from the asphaltene micelle during the separation and vanadyl porphyrins bearing high-molecular-weight substituents

  12. The aggregation and diffusion of asphaltenes studied by GPU-accelerated dissipative particle dynamics

    Wang, Sibo; Xu, Junbo; Wen, Hao


    The heavy crude oil consists of thousands of compounds and much of them have large molecular weights and complex structures. Studying the aggregation and diffusion behavior of asphaltenes can facilitate the understanding of the heavy crude oil. In previous studies, the fused aromatic rings were treated as rigid bodies so that dissipative particle dynamics (DPD) integrated with the quaternion method can be used to study asphaltene systems. In this work, DPD integrated with the quaternion method is implemented on graphics processing units (GPUs). Compared with the serial program, tens of times speedup can be achieved when simulations performed on a single GPU. Using multiple GPUs can provide faster computation speed and more storage space for simulations of significant large systems. By using large systems, simulations of the asphaltene-toluene system at extremely dilute concentrations can be performed. The determined diffusion coefficients of asphaltenes are similar to that in experimental studies. At last, the aggregation behavior of asphaltenes in heptane was investigated, and the simulation results agreed with the modified Yen model. Monomers, nanoaggregates and clusters were observed from the simulations at different concentrations.

  13. Asphaltene precipitation and its effects on the vapour extraction (VAPEX) heavy oil recovery process

    Luo, P.; Wang, X.; Gu, Y. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Regina Univ., SK (Canada). Petroleum Technology Research Centre; Zhang, H. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Core Laboratories Canada Ltd., Calgary, AB (Canada); Moghadam, L. [Fekete Associates Inc., Calgary, AB (Canada)


    One of the most important physical phenomena during the solvent vapour extraction (VAPEX) of heavy oil recovery is asphaltene precipitation. After the asphaltene precipitation occurs, the produced heavy oil is deasphalted in-situ, resulting in a lower viscosity and better quality. However, precipitated asphaltenes may plug some small pores of the reservoir formation, thus reducing its permeability. This paper examined the effects of three operating factors on the asphaltene precipitation during the VAPEX process, notably solvent type; operating pressure; and sand-pack permeability. Eight VAPEX tests were conducted to recover two different Lloydminster heavy oil samples from a rectangular sand-packed physical model with a butane mixture and propane as the respective solvents. The accumulative heavy oil and solvent production from the physical model were measured in the entire VAPEX process. The paper described the materials, experimental set-up, and experimental preparation. The VAPEX test was also explained. Results were presented for sand consolidation; solvent effect; pressure effect; and permeability effect. It was concluded that when the extracting solvent is in a liquid-gas state, asphaltene precipitation occurs and leads to in-situ deasphalting. 15 refs., 3 tabs., 6 figs.

  14. Molecular mechanics and microcalorimetric investigations of the effects of molecular water on the aggregation of asphaltenes in solutions

    Murgich, J.; Lira-Galeana, C.; Garcia, Daniel Merino; Andersen, Simon Ivar; del Rio-Garcia, J.M.


    The interaction of two model asphaltene molecules from the Athabasca sand oil with a water molecule in a toluene solution was studied by means of molecular mechanics calculations. It was found that water forms bridging H bonds between the heteroatoms of asphaltenes with a considerable span in ene...

  15. Characterization of the onset asphaltenes by focused-beam laser reflectance : a tool for chemical additives screening

    Marugan, J.; Calles, J.A.; Dufour, J.; Gimenez-Aguirre, R. [Univ. Rey Juan Carlos, Madrid (Spain). URJC-Repsol-YPF Flow Assurance Laboratory, Dept. of Chemical and Environmental Technology; Pena, J.L. [Univ. Rey Juan Carlos, Madrid (Spain). URJC-Repsol-YPF Flow Assurance Laboratory, Dept. of Chemical and Environmental Technology; Centro Tecnologico Repsol-YPF, Madrid (Spain); Merino-Garcia, D. [Centro Tecnologico Repsol-YPF, Madrid (Spain)


    The deposition of asphaltenes in crude oil can cause flow assurance problems. In this study, a laser reflectance technique known as Focused-Beam Reflectance Measurement (FBRM) was used to study the kinetics of asphaltenes aggregation near onset. The FBRM tool provides a very sensitive way of determining the onset n-alkane/oil mass ratio. The influence of the n-alkane solvent and temperature on the solvent/oil threshold ratio of 2 South American crude oils with 21 and 27 API were investigated. The FBRM technique provided kinetic information about the evolution with time of the size distribution of asphaltenes flocs. Additional FBRM experiments of asphaltene redissolution and reprecipitation were also performed for a comparative evaluation, beginning with the solids recovered following the IP- 143 standard, which were fractionated into 4 different polarity groups using n-pentane - chloroform mixtures. The objective was to find correlations between polarity of the asphaltenes and its instability near the onset. Metal content was determined through atomic emission spectroscopy. The solids were characterized by 1H NMR, FT-IR spectroscopy, and vapour-pressure osmometry in order to determine the chemical and structural features of the most unstable asphaltenes. The FBRM probe was used to screen commercial chemical additives to prevent asphaltenes deposits. This technique was shown to be a very powerful tool for examining the influence of additives on the aggregation kinetics and the particle size distribution of the first asphaltene solids.

  16. Isothermal Titration Calorimetry and Fluorescence Spectroscopy Study Of Asphaltene Self-Association In Toluene And Interaction With A Model Resin

    Garcia, Daniel Merino; Andersen, Simon Ivar


    This article collects the work performed by Isothermal Titration Caloritnetry (ITC) in the study of the self-association of asphaltenes in toluene solutions. Calorimetric experiments show that asphaltenes, start self-associating at very low concentrations and that the existence of a Critical Mice...

  17. Removal of asphaltene and paraffin deposits using micellar solutions and fused reactions. Final report, 1995--1997

    Chang, C.L.; Nalwaya, V.; Singh, P.; Fogler, H.S.


    Chemical treatments of paraffin and asphaltene deposition by means of cleaning fluids were carried out in this research project. Research focused on the characterization of asphaltene and paraffin materials and dissolution of asphaltene and paraffin deposits using surfactant/micellar fluids developed early in the project. The key parameters controlling the dissolution rate were identified and the process of asphaltene/paraffin dissolution were examined using microscopic apparatus. Numerical modeling was also carried out to understand the dissolution of paraffin deposits. The results show that fused chemical reaction systems are a promising way of removing paraffin deposits in subsea pipelines. The fused system may be in the form of alternate pulses, emulsions systems or encapsulated catalyst systems. Fused reaction systems, in fact, are extremely cost-effective--less than 10% of the cost of replacing entire sections of the blocked pipeline. The results presented in this report can have a real impact on the petroleum industry and the National Oil Program, if it is realized that the remediation technologies developed here can substantially delay abandonment (due to asphaltene/paraffin plugging) of domestic petroleum resources. The report also sheds new light on the nature and properties of asphaltenes and paraffin deposits which will ultimately help the scientific and research community to develop effective methods in eliminating asphaltene/paraffin deposition problems. It must also be realized that asphaltene remediation technologies developed and presented in this report are a real alternative to aromatic cleaning fluids currently used by the petroleum industry.

  18. Calorimetric Evidence about the Application of the Concept of CMC to Asphaltene Self-Association

    Garcia, Daniel Merino; Andersen, Simon Ivar


    For many years, the concept of critical micellar concentration (CMC) has been projected from surfactant science into asphaltene science. There are several similarities between these two species, such as the stabilization of water-in-oil emulsions and surface activity, which suggested that...... asphaltenes may also have a concentration at which self-association occurs (CMC). This article presents evidence found by calorimetry and spectroscopic techniques, that suggest that this concept may not be adequate for asphaltene self-association in toluene solutions. Isothermal titration calorimetry has been...... widely used in surfactant science to determine both the CMC and the enthalpy of micellation of many surfactants. The concentration interval could be divided into three regions: monomer region, micellation region, and micelle region. The absence of the first region (monomer) in the concentration range...

  19. Structural modifications of petroleum asphaltenes by reductive alkylation investigated by TLC-FID

    Cagniant, D.; Nosyrev, I.; Cebolla, V.; Vela, J.; Membrado, L.; Gruber, R. [Universite de Metz, Metz (France). Laboratoire de Thermodynamique et d' Analyses Chimiques


    The reductive alkylation of a French petroleum asphaltene (Lagrave) was studied with potassium in THF, in absence of an electron transfer reagent. From the number of butyl and benzyl groups added to the starting asphaltene, the difference of reactivity of the alkyl reagents, butyl iodide and benzyl bromide, was pointed out. Special attention was focused on the cleavage of C-S and C-O linkages in relation to the structural modifications. From the number of hydrogen atoms added during the reduction step, it was concluded that the sulphide linkages are mainly of aryl-S-aryl, aryl-S-alkyl or alkyl-S-alkyl types. The TLC-FID (Iatroscan) analysis was found to be very suitable to follow the 'depolymerization' process of the asphaltene, qualitatively as well as quantitatively, by the application hydrocarbon group type analysis. 23 refs., 2 figs., 5 tabs.

  20. Sulfur K-edge X-ray absorption spectroscopy of petroleum asphaltenes and model compounds

    The utility of sulfur K-edge X-ray absorption spectroscopy for the determination and quantification of sulfur forms in petroleum asphaltenes has been investigated. Both X-ray absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra were obtained for a selected group of model compounds and for several petroleum asphaltene samples. For the model compounds the sulfur XANES was found to vary widely from compound to compound and to provide a fingerprint for the form of sulfur involved. The use of third derivatives of the spectra enabled discrimination of mixtures of sulfidic and thiophenic model compounds and allowed approximate quantification of the amount of each component in the mixtures and in the asphaltene samples. These results represent the first demonstration that nonvolatile sulfur forms can be distinguished and approximately quantified by direct measurement

  1. A study of some asphaltenes solutions structure and of a Safaniya vacuum residue

    Guille, V.


    A lot of problems in the petroleum industry are due to the presence of asphaltenes compounds in petroleum products. A good knowledge of the chemical composition and the different properties of asphaltenes in solution are necessary to cope with these difficulties. We have then examined a Safaniya Vacuum Residue (VR) and its fractions (asphaltenes, resins, aromatics and saturates). In order to describe the macro-structure of these complex colloidal systems, we used different characterisation techniques: small angle X-ray and neutron scattering (SAXS and SANS), rheology and electron microscopy. Scattering techniques allows us to precise the model for asphaltenes and resins in solution. These macromolecules are poly-dispersed disk-like particles with thickness and diameter which are respectively close to 1 to 10 nm. The average molecular weight is equal to 106 000 for asphaltenes and 3 300 for resins. We have shown that SAXS is more sensitive to the scattering of the aromatic part of the molecule. Adding n-heptane induces first a de-solvation of the molecules and then an aggregation up to flocculation. These solutions present large heterogeneities due to concentration fluctuations. A huge difference in the chemical composition of the different asphaltenes molecules can explain these fluctuations. These heterogeneities are stable as a function of temperature; this means that exist strong molecular interactions. Ultracentrifugation gives two different fractions which contain different chemical structures, more or less aromatic. Solutions, in good solvent, of these two fractions are homogeneous but a mixture of these two fractions exhibits, heterogeneities. SAXS gives information about the structure of VR. We have observed the presence of large density fluctuations up to 300 deg. C. Rheological measurements confirm three-dimensional organisation. (author). 11 refs., 11 figs., 49 tabs.

  2. Effects of Asphaltene Aggregation in Model Heptane-Toluene Mixtures on Stability of Water-in-Oil Emulsions

    McLean; Kilpatrick


    As part of an ongoing investigation into the stability of water-in-crude oil emulsions, model oils have been utilized to further probe the effects of crude solvency as well as specific resin-asphaltene interactions on emulsion stability. These model oils were constructed by dissolving varying amounts of resins and/or asphaltenes in a mixture of heptane and toluene. The resins and asphaltenes used in this study were isolated from four different crude types-Arab Berri (AB), Arab Heavy (AH), Alaska North Slope (ANS), and San Joaquin Valley (SJV)-and characterized in a previous study using heptane precipitation of the asphaltenes followed by an extrographic separation of the resins from silica gel. Asphaltenes dissolved in heptol at concentrations of just 0.5% were shown to generate emulsions which were even more stable than those generated from their respective whole crude oils. Some types of resins (e.g., from AH and SJV) also demonstrated an ability to stabilize emulsions although these resin-stabilized emulsions were considerably less stable than those prepared with asphaltenes. The primary factors governing the stability of these model emulsions were the aromaticity of the crude medium (as controlled by the heptane:toluene ratio), the concentration of asphaltenes, and the availability of solvating resins in the oil (i.e., the resin/asphaltene or R/A ratio). The model emulsions were the most stable when the crude medium was 30-40% toluene and in many cases at small R/A ratios (i.e., R/A asphaltenes are the most effective in stabilizing emulsions when they are near the point of incipient precipitation. The types of resins and asphaltenes used to construct these model oils also played a role in determining the resultant emulsion stability which indicates the importance of specific resin-asphaltene interactions. The interfacially active components that stabilized these model systems were the most polar and/or condensed portions of the resin and asphaltene fractions as

  3. Fractal characteristics of an asphaltene deposited heterogeneous surface

    Several methods have been employed in recent years to investigate homogeneous surface topography based on image analysis, such as AFM (atomic force microscopy) and SEM (scanning electron microscopy). Fractal analysis of the images provides fractal dimension of the surface which is used as one of the most common surface indices. Surface topography has generally been considered to be mono-fractal. On the other hand, precipitation of organic materials on a rough surface and its irregular growth result in morphology alteration and converts a homogeneous surface to a heterogeneous one. In this case a mono-fractal description of the surface does not completely describe the nature of the altered surface. This work aims to investigate the topography alteration of a glass surface as a result of asphaltene precipitation and its growth at various pressures using a bi-fractal approach. The experimental results of the deposited surfaces were clearly indicating two regions of micro- and macro-asperities namely, surface types I and II, respectively. The fractal plots were indicative of bi-fractal behavior and for each surface type one fractal dimension was calculated. The topography information of the surfaces was obtained by two image analyses, AFM and SEM imaging techniques. Results of the bi-fractal analysis demonstrated that topography alteration in surface type II (macro-asperities) is more evident than that in surface type I (micro-asperities). Compared to surface type II, a better correlation was observed between the fractal dimensions inferred from the AFM images (DA) and those of the SEM images (DS) in surface type I.

  4. Monitoring the formation of asphaltene and pre-asphaltene through solvent soaking during liquefaction of Mukah Malingian Malaysian coal via semi-continuous solvent flow high-pressure reactor system

    Khudzir Ismail; Nur Nasulhah Kasim; Mohd Azlan Mohd Ishak; Mohd Fauzi Abdullah [University Technology MARA Perlis, Perlis (Malaysia). Fuel Combustion Research Laboratory


    One of the problems that could affect the production of high percentage of oil + gas yield during liquefaction of low-rank coal is the production of high amount of asphaltene, pre-asphaltene and coke through de-polymerisation and re-polymerisation of the radical species within the coal carbon matrix at high temperature regime. Hence, one solution is to suppress the re-polymerisation reaction by supplying sufficient amount of fresh donor solvent at the appropriate liquefaction temperature to instantaneously cap the reactive radical species. In this work, the effect of solvent flow rates and solvent soaking time at selective isothermal temperatures on the formation of asphaltene and preasphaltene during liquefaction of Mukah Balingian low-rank Malaysian coal via semi-continuous solvent flow high-pressure reactor system were studied. The liquefaction processes were carried out at 4 MPa with three different solvent flow rates i.e. at 2, 7, and 10 ml/min, and at temperature ranging from 300 to 450{sup o}C by using tetralin as hydrogen donor solvent. Initial findings showed that asphaltene and pre-asphaltene begin to form at liquefaction temperature range of 300-350{sup o}C, with the percent yields tend to increase with increasing in the solvent flow rate and solvent soaking time. At above 400{sup o}C, the percent of asphaltene and pre-asphaltene seem to decrease slightly probably due to conversion of these components to oil + gas. The slight reduction in the percentage of asphaltene and pre-asphaltene suggest that sufficient amount of hydrogen donors were present during the soaking condition to cap the small radical species, thus preventing the re-polymerisation reaction and promoting the formation of oil+gas. Apparently, the percentages of coal conversion and oil + gas yield were almost similar regardless whether the solvent soaking was applied at 400 or 420{sup o}C. 18 refs., 4 figs., 4 tabs.

  5. Effect on molecular interactions of chemical alteration of petroleum asphaltenes. I

    Juyal, Priyanka; Garcia, Daniel Merino; Andersen, Simon Ivar


    Asphaltenes are naturally occurring components of crude oil and have been the subject of many studies that have involved a variety of methods to determine their complex structure, their association in crude oil with resins, and their agglomeration phenomena. Yet, the molecular structures of aspha...

  6. Determination of asphaltene onset conditions using the cubic plus association equation of state

    Arya, Alay; von Solms, Nicolas; Kontogeorgis, Georgios M.


    The cubic-plus-association (CPA) equation of state (EoS) has already been proven to be a successful model for phase equilibrium calculations for systems containing associating components and has already been applied for asphaltene modeling by few researchers. In the present work, we apply the CPA...

  7. Investigating the factors influencing recovery of asphaltenic oil by water and miscible CO{sub 2} flooding

    Chukwudeme, Edwin Andrew


    Conclusions that may be drawn from this work on the influence of CO{sub 2}, temperature, pressure and water composition on the recovery of asphaltenic oil by water and CO{sub 2} flooding are as follows: Asphaltene is found to alter outcrop chalk wettability from water-wet to more oil wet, which influence oil recovery by miscible CO{sub 2} and water flooding. Modification of Hirschberg solubility model for predicting asphaltene deposition has been done to account for the effect of CO{sub 2} fraction in the liquid phase during miscible flooding. This is done based on data from this work and literature. This model made it possible to isolate the effect of CO{sub 2} fraction in liquid phase on asphaltene deposition during miscible flooding. Hence, determine the critical fraction of CO{sub 2} that initiate the asphaltene deposition. The critical fraction of CO{sub 2} is estimated to be between 17 to 42 mol percent (mol%), with 33 mol% as average value. A ternary diagram is developed and is based on solubility parameter ratio (S.P.R) and molar volume ratio (V{sub CO2}/V{sub L}) and their relation to asphaltene deposition using data from this work and literature. From this data, it may be suggested that S.P.R is a determining factor for asphaltene deposition during CO{sub 2} flooding, which is not unreasonable since it is influenced by the molar volume ratio, hence temperature, pressure and composition. It is interesting to see a linear relationship between asphaltene precipitation and pressure drop regardless of the flowing pressure at isothermal condition. This is tested for under-saturated fluids. Oil recovery by miscible CO{sub 2} flooding shows low ultimate oil recovery with increasing temperature and pressure for asphaltenic oil compared to non-asphaltenic. CO{sub 2} flooding is found to be plausible for asphaltenic reservoir at lower temperature (< 70 C). From simulation studies, EOR by CO{sub 2} initiated after at least three years of water injection show the

  8. Separation and characterization of resins and asphaltenes coming from Castilla crude Evaluation of their molecular interaction

    The study of resins and asphaltenes, the heaviest fractions of oil, has become an area of interest due to the abundance of heavy crude oils in Colombia and Latin America. We studied the chemical composition of the heavy fractions of Castilla crude oil, evaluated some of its molecular parameters and found evidence of the interaction between the resins extracted from the crude with the asphaltenes of the original crude. With this objective, we carried out at the pilot plant level precipitation of the resin-asphaltene (R-A) aggregate by adding and mixing under controlled conditions, a paraffin solvent, from the Apiay refinery, called Apiasol. By extracting Soxhlet with the same solvent, resin 1 of aggregate R-A was separated. Resin ll defined as the soluble fraction that is part of the maltenes, was separated from the deasphalted crude by open column chromatography, using alumina as support, according to the SAR method (Saturated, Aromatics, Resins). The fractions of resins and the asphaltenes obtained, were characterized by: Nuclear Magnetic Resonance (NMR), FT-lR, DRX, elementary analysis (C, H, N, S), metal content (Ni and V), distribution of molecular weight by GPC, and average molecular weight by VPO. The results obtained show evidence that resin l which is part of the aggregate has less average molecular weight than resin ll which is present in the fraction of maltenes. In addition, some changes were found in the elementary analysis of among the resins. On the one hand, and taking into account the existing theories of molecular interactions among these fractions, it was found that the resins l separated from the R-A aggregate, when added to the crude, they stabilize their asphaltenes. This evaluation was carried out by analyzing the flocculation point of the crude and its mixtures with 1,9% and 3,8% of resin l, when they are titrated with a precipitating agent in an NIR cell that works with high pressure and temperature

  9. Dynamic Surface Properties of Asphaltenes and Resins at the Oil-Air Interface.

    Bauget, Fabrice; Langevin, Dominique; Lenormand, Roland


    Because of the existence of large reserves, the production of heavy oils is presently the object of much interest. Some heavy oil reservoirs show anomalous behavior in primary production, with rates of production better than predicted. In Canada and Venezuela some heavy oils are produced in the form of "bubbly" oil, which is stable for several hours in open vessels. These crude oils are therefore commonly called "foamy oils". Since the presence of bubbles could be responsible for an enhanced rate of production, a better knowledge of the properties of the gas-oil interface is desirable. We have experimentally studied the effect of concentration of asphaltenes and resins on static and dynamic properties of oil-air interfaces and also on bulk viscosity. The experiments include surface tension measurements using the pendant-drop method, surface viscosity by the oscillating-drop method, foamability by continuous gas injection, and film lifetime. All the experiments were performed using resins and asphaltenes in toluene solutions at 20 degrees C. At first asphaltenes enhance foamability and film lifetime. All the experiments performed showed a change in regime for asphaltene concentrations around 10% by weight, possibly due to clustering. At the studied concentrations, the adsorption process at the air-oil interface is not diffusion controlled but rather involves a reorganization of asphaltene molecules in a network structure. The formation of a solid skin is well identified by the increase of the elastic modulus. This elastic modulus is also an important property for foam stability, since a rigid interface limits bubble rupture. The interface rigidity at long times decreases with increases in resin fraction, which could decrease foam stability as well as emulsion stability. Copyright 2001 Academic Press. PMID:11427016

  10. Compositional thermodynamic model of asphaltenes flocculation out of crudes; Modelisation thermodynamique compositionnelle de la floculation des bruts asphalteniques

    Szewczyk, V.


    The aim of this work is to propose to the oil industry a compositional thermodynamic model able to predict the operating conditions which induce asphaltenes flocculation out of crudes. In this study, various analytical methods (calorimetry, elemental analysis, {sup 13}C nuclear magnetic resonance, neutron diffusion,...) have been used in order to get a better description of the asphaltene fraction to infer its flocculation mechanism. The proposed model describes this flocculation as a thermodynamic transition inducing the formation of a new liquid phase with a high asphaltene content and formed by all the components initially in the crude: the asphaltene deposit. Asphaltenes are represented as a pseudo-component essentially made of carbon and hydrogen. The analytical modelling of the F11-F20 light fraction is the one proposed by Jaubert (1993). The F20+ heavy fraction is represented by four pseudo-components, their physical properties are calculated using the group contribution methods of Avaullee (1995) and of Rogalski and Neau (1990). The Peng-Robinson equation of state (1976) combined with the Abdoul and Peneloux group contribution mixing rules (1989) is used in order to restitute the gas-liquid-asphaltene deposit phase equilibria. This model not being able to compute flocculation conditions on a predictive manner, the method consists in fitting some physical properties of the pseudo-components introduced in the analytical representation of the asphaltene crudes. he obtained results show results show that the proposed flocculation model is then well adapted to the description of the thermodynamic properties (saturation pressures, relative volumes, flocculation curves) of asphaltene crudes within a relatively large range of temperature (30-150 deg C) and pressure (0.1-50 MPa), covering the majority of conditions met in oil production. (author) 109 refs.

  11. Problematic stabilizing films in petroleum emulsions: shear rheological response of viscoelastic asphaltene films and the effect on drop coalescence.

    Harbottle, D; Q. Chen; Moorthy, K.; Wang, L.; Xu, S; Liu, Q.; Sjoblom, J; Z. Xu


    Adsorption of asphaltenes at the water-oil interface contributes to the stability of petroleum emulsions by forming a networked film that can hinder drop-drop coalescence. The interfacial microstructure can either be liquid-like or solid-like, depending on (i) initial bulk concentration of asphaltenes, (ii) interfacial aging time, and (iii) solvent aromaticity. Two techniques--interfacial shear rheology and integrated thin film drainage apparatus--provided equivalent interface aging condition...

  12. The influence of petroleum asphaltenic sub fractions on the demulsifiers performance; Influencia de subfracoes asfaltenicas de petroleo sobre a acao de desemulsificantes

    Honse, Siller O.; Mansur, Claudia R.E.; Lucas, Elizabete F. [Universidade Federal do Rio de Janeiro (IMA/UFRJ), RJ (Brazil). Inst. de Macromoleculas. Lab. de Macromoleculas e Coloides na Industria de Petroleo], e-mail:


    The aim of this work is to evaluate the influence of asphaltene fractions and subfractions on the stabilization of petroleum emulsions, as well as on the efficiency of demulsifiers based on poly(ethylene oxide-b-propylene oxide) (PEO-PPO). Asphaltenes were extracted from an asphaltic residue using n-heptane (C5 asphaltenes) and n-decane (asphaltenes C10). Intermediate subfractions were also obtained. Model emulsions, consisted of water and dispersions of the asphaltene in toluene were prepared, with and without adding demulsifier. The stability of the emulsions was higher when adding more polar fractions. However, asphaltenes presenting a broad distribution of polarity cause higher emulsion stability than that presenting very narrow distribution of intermediate polarity. The efficiency of PEO-PPO copolymer on emulsions separation is related to the original stability of the emulsions. In this work, it was confirmed that branched surfactant presents higher efficiency than the linear. (author)

  13. Chemistry and structure of coal-derived asphaltenes, Phase III. Quarterly progress report, January--March 1978

    Yen, T. F.


    The solubility limits of Synthoil and PAMCO asphaltenes have been measured as a function of Hildebrand solubility parameters and hydrogen bonding. Solvents with moderate hydrogen bonding capacity such as dioxane, ethyl benzoate and dibutyl phthalate were found to be most effective in dissolving asphaltenes over the widest range of solubility parameters. VPO molecular weight studies of coal liquid derived carbenes, as a function of concentration in the solvent THF, indicate that these fractions are more strongly self-associated than the corresponding asphaltenes, and generally afford high infinite dilution number average molecular weights: Synthoil, 861; HRI H-Coal, 1156; Cat. Inc. SRC, 1228; PAMCO SRC, 1054. The variable ESR temperature dependence of the spin intensity for a Synthoil asphaltene-I/sub 2/ charge transfer followed a 1/T (Curie--Weiss) dependence over the temperature range from 25/sup 0/ to -114/sup 0/C suggesting that independent, non-interacting donor and acceptor doublets were formed. Weight percent OH values, determined from 'H NMR analysis of silylated asphaltenes, were found to provide a reasonably linear correlation with the absorbance of the monomeric OH infrared stretching bands of the asphaltenes.

  14. Molecular Dynamics Simulation: The Behavior of Asphaltene in Crude Oil and at the Oil/Water Interface

    Gao, Fengfeng


    Carboxyl asphaltene is commonly discussed in the petroleum industry. In most conditions, electroneutral carboxyl asphaltene molecules can be deprotonated to become carboxylate asphaltenes. Both in crude oil and at the oil/water interface, the characteristics of anionic carboxylate asphaltenes are different than those of the carboxyl asphaltenes. In this paper, molecular dynamics (MD) simulations are utilized to study the structural features of different asphaltene molecules, namely, C5 Pe and anionic C5 Pe, at the molecular level. In crude oil, the electroneutral C5 Pe molecules prefer to form a steady face-to-face stacking, while the anionic C5 Pe molecules are inclined to form face-to-face stacking and T-shaped II stacking because of the repulsion of the anionic headgroups. Anionic C5 Pe has a distinct affinity to the oil/water interface during the simulation, while the C5 Pe molecules persist in the crude oil domain. A three-stage model of anionic C5 Pe molecules adsorbed at the oil/water interface is finally developed.

  15. Application of the PC-SAFT EoS in the definition of a universal plot for asphaltene stability

    Vargas, F.; Hirasaki, G.; Chapman, W. [Rice Univ., Houston, TX (United States). Dept. of Chemical and Biomolecular Engineering; Gonzalez, D. [Rice Univ., Houston, TX (United States). Dept. of Chemical and Biomolecular Engineering; Schlumberger, Houston, TX (United States); Wang, J.; Creek, J. [Chevron Energy Technology Co., Houston, TX (United States); Buckley, J. [New Mexico Tech, Socorro, NM (United States). PRRC


    This paper presented a new tool to model asphaltene stability under reservoir conditions. Asphaltene poses a problem in deep water production because of it has the tendency to precipitate, and the mechanisms of aggregation and deposition are not completely understood. A universal model is needed to predict the stability of these species, under different conditions. This paper presented advances in developing a general method to model asphaltene stability in oil, using the PC-SAFT Equation of State (EoS), regardless of the oil components and their compositions. The PC-SAFT EoS is an alternative to the Flory-Huggins theory (FHT) and has been successfully used to model asphaltene stability. By defining dimensionless parameters, the equilibrium curves of different multicomponent mixtures collapse onto one single curve. The obtained universal plots for the bubble point and the onset of asphaltene precipitation were found to be in excellent agreement with results obtained from simulations. This paper also presented an extension of this model to mixtures containing dissolved gases, such as methane, carbon dioxide and ethane. The study also addressed the issue regarding the validity of the current mixing rule for solubility parameters of mixtures containing dissolved gases. A new mixing rule was derived for solubility parameters of mixtures containing liquids and dissolved gases. There was good agreement between simulation results and refractive index measurements. In addition, the universal curves for asphaltene stability and the corresponding dimensionless numbers proposed in this study can be obtained using this new mixing rule.

  16. Polymer solution and lattice theory applications for modeling of asphaltene precipitation in petroleum mixtures

    S. A. Mousavi-Dehghani


    Full Text Available Here asphaltene precipitation in petroleum reservoirs during natural depletion and miscible gas injection is modeled via two distinct and new methods (polymer solution and lattice theories. The first model is based on the polymer solution theory, which is a combination of Miller's combinatorial term with a modified residual term of the original Flory-Huggins theory. The second one is the application of the well-known Sanchez-Lacombe equation of state (SL EOS to describe the phase behavior of asphaltene compounds in crude oil. The results of both models show an acceptable and good agreement between the real data (field and experimental and these two models. As it can be seen from the obtained results of these two models, it seems application of the lattice or polymer solution theories (based on The Miller's combinatorial term could give the better and more close to real data.

  17. Fullerenes in asphaltenes and other carbonaceous materials: natural constituents or laser artifacts.

    Santos, Vanessa G; Fasciotti, Maíra; Pudenzi, Marcos A; Klitzke, Clécio F; Nascimento, Heliara L; Pereira, Rosana C L; Bastos, Wagner L; Eberlin, Marcos N


    The presence of fullerenes as natural constituents of carbonaceous materials or their formation as laser artifacts during laser desorption ionization (LDI) mass spectrometry (MS) analysis is reinvestigated and reviewed. The results using asphaltene samples with varying composition as well as standard polycyclic aromatic hydrocarbons (PAH) and fullerene samples as models have demonstrated that indeed Cn ring fullerenes are not natural constituents but they are formed as common and often as predominant artifacts upon laser radiation, and a series of incorrect assignments based on LDI-MS data of several carbonaceous materials seems unfortunately to have been made. When the present results are evaluated also in the light of the vast literature on LDI-MS of carbonaceous materials, the formation of fullerene artifacts seems particularly common for LDI-MS analysis of asphaltenes and other carbonaceous samples with considerably high levels of PAH and varies according to the type of laser used, and the intensity of the laser beam. PMID:26805430

  18. Reduction of Water/Oil Interfacial Tension by Model Asphaltenes: The Governing Role of Surface Concentration.

    Jian, Cuiying; Poopari, Mohammad Reza; Liu, Qingxia; Zerpa, Nestor; Zeng, Hongbo; Tang, Tian


    In this work, pendant drop techniques and molecular dynamics (MD) simulations were employed to investigate the effect of asphaltene concentrations on the interfacial tension (IFT) of the oil/water interface. Here, oil and asphaltene were represented by, respectively, common organic solvents and Violanthrone-79, and two types of concentration, i.e., bulk concentration and surface concentration, were examined. Correlations between the IFTs from experiments and MD simulations revealed that surface concentration, rather than the commonly used bulk concentration, determines the reduction of oil/water IFTs. Through analyzing the hydrogen bonding, the underlying mechanism for the IFT reduction was proposed. Our discussions here not only enable the direct comparison between experiments and MD simulations on the IFTs but also help with future interfacial studies using combined experimental and simulation approaches. The methodologies used in this work can be extended to many other oil/water interfaces in the presence of interfacially active compounds. PMID:27268710

  19. Experimental Study and Mathematical Modeling of Asphaltene Deposition Mechanism in Core Samples

    Jafari Behbahani T.; Ghotbi C.; Taghikhani V.; Shahrabadi A.


    In this work, experimental studies were conducted to determine the effect of asphaltene deposition on the permeability reduction and porosity reduction of carbonate, sandstone and dolomite rock samples using an Iranian bottom hole live oil sample which is close to reservoir conditions, whereas in the majority of previous work, a mixture of recombined oil (a mixture of dead oil and associated gas) was injected into a core sample which is far from reservoir conditions. The effect of the oil inj...

  20. Polymer solution and lattice theory applications for modeling of asphaltene precipitation in petroleum mixtures

    S. A. Mousavi-Dehghani; Mirzayi, B.; M. Vafaie-Sefti


    Here asphaltene precipitation in petroleum reservoirs during natural depletion and miscible gas injection is modeled via two distinct and new methods (polymer solution and lattice theories). The first model is based on the polymer solution theory, which is a combination of Miller's combinatorial term with a modified residual term of the original Flory-Huggins theory. The second one is the application of the well-known Sanchez-Lacombe equation of state (SL EOS) to describe the phase behavior o...

  1. Organic flow assurance: Asphaltene dispersant/inhibitor formulation development through experimental design

    Abrahamsen, Eirin L.


    The exploitation of hydrocarbon has forced the petroleum production to move closer to extreme climate areas and deep waters such as the Barents Sea. These challenges require effective and safe production, transport and processing of the petroleum sources. Chemical and physical changes in the reservoir may cause different types of unpredicted problems such as organic deposits which are mainly asphaltene and wax precipitation. Wax precipitation is very common in subsea pipelines....

  2. Correlations between diamagnetic properties and structural characters of asphaltenes and other heavy petroleum products

    El-Mohamed, S.; Achard, M.-F.; Hardouin, F.; Gasparoux, H.


    Magnetic susceptibility measurements are made at room temperature on heavy petroleum products. They provide characteristic values of the diamagnetism of such organic compounds with high molecular masses. By the use of the Pascal's rules the average number of condensed aromatic rings, in asphaltenes and other heavy petroleum fractions, must be small and undoubtedly less than in the well-known Yen's model. 10 refs., 4 figs., 4 tabs.


    Shkidchenko, Alexander; Akhmetov, Lenar; Gafarov, Arslan


    The possibility of biodegradation of asphaltenes at a room temperature by single aerobic strains Microbacterium liquefaciens Ash-10, Pseudomonas putida Ash-4, Rhodococcus erythropolis Sh-3 and Bacillus sp. 2, isolated from soil with chronic petroleum pollution has been shown. All strains possess high oil-utilizing activity and the ability to grow on agar media containing polycondensed hydrocarbons, black oil, alcohol-benzene resins, benzene resins as sole sources of carbon and energy. The str...

  4. Rheological, dielectric and structural characterization of asphaltene suspensions under DC electric fields

    L. Rejon; O. Manero; C. Lira-Galeana [Instituto de Investigaciones Electricas, Morelos (Mexico)


    The rheological, dielectric and structural behavior of suspensions composed of silicon oil and asphaltene particles under DC electric fields are investigated experimentally. In the absence of an electric field, the suspensions show a near Newtonian behavior. When the electric field (E) is applied, the suspensions behave as Bingham plastics with a yield stress that varies as a power of the electric field. The increase in the viscosity of the suspensions (electrorheological phenomenon, ER) is more accentuated at low shear rates and depends on the electric field intensity. The resulting rheological behavior can be attributed to the formation of structures induced by the electric field, and they break when the shear rate is increased. The relation between the structural arrangements of the suspension under an electric field and the rheological behavior is analyzed in this study. Results show that the ER response of asphaltene suspensions is not as large as that observed in conventional ER fluids, but nevertheless they throw light on the contribution of electrorheological mechanisms upon asphaltene particle aggregation observed in the transport of the crude oil in the petroleum industry. 17 refs., 10 figs., 1 tab.

  5. Air oxidation of the kerogen/asphaltene vanadyl porphyrins: an electron spin resonance study



    Full Text Available The thermal behavior of vanadyl porphyrins was studied by electron spin resonance during heating of kerogens, isolated from the La Luna (Venezuela and Serpiano (Switzerland bituminous rocks, at 25°C for 1 to 20 days in the presence of air. During the thermal treatment of the kerogens, the vanadyl porphyrins resonance signals decrease monotonically and become quite small after 6 days of heating. Concomitantly, new vanadyl signals appear and, at longer heating times, dominate the spectrum. It is suggested that the secondary vanadyl species must have been formed from vanadyl porphyrins. Similar conversions of vanadyl porphyrins are observed under the same experimental conditions for asphaltenes extracted from the La Luna and Serpiano rocks, and floating asphalt from the Dead Sea (Israel. A comparison of the spin-Hamiltonian parameters for vanadyl porphyrins and the vanadyl compounds obtained during pyrolysis of the kerogens/asphaltenes suggests that the latter are of a non-porphyrin type. For comparison a study was conducted on Western Kentucky No. 9 coal enriched with vanadium (>>400 ppm from six mines. All the coal samples show only the presence of predominant by non-porphyrin vanadyl compounds, similar to those generated through laboratory heating of the kerogens/asphaltenes in air. In addition, some samples also contain a minor amount of vanadyl porphyrins.

  6. Syngas obtainment from the gasification of asphaltenes of the San Fernando crude oil

    In this work, we developed the first study in Colombia to obtain and evaluate syngas compositions derived from asphaltenes gasification. These asphaltenes came from the implementation of a Deasphalting process to San Fernando crude oil, with the purpose of looking for technological options for their utilization. We performed the design, installation and commissioning of facilities for the gasification of asphaltenes at laboratory scale, it following an experimental methodology, performing nine tests and considering temperature and agent gasification quantity (oxygen) as independent variables. The syngas derived from gasification was analyzed by two chromatographic techniques, which reported the presence of refinery gases and sulfur. We evidenced a growth tendency of CO, H2 and sulfur composition and a decrease in CH4 and CO2 composition with temperature. The composition of the syngas was evaluated with different quantities of gasification agent (33%, 40% and 47% the amount of oxygen theoretically required for complete combustion) at each temperature levels operated. It was established that when using a 40% of gasification agent, you get greater average content of CO and H2, which are the interest gases in the gasification process.

  7. Colloidal asphaltene deposition in laminar pipe flow: Flow rate and parametric effects

    Hashmi, S. M.; Loewenberg, M.; Firoozabadi, A.


    Deposition from a suspended phase onto a surface can aversely affect everyday transport processes on a variety of scales, from mineral scale corrosion of household plumbing systems to asphaltene deposition in large-scale pipelines in the petroleum industry. While petroleum may be a single fluid phase under reservoir conditions, depressurization upon production often induces a phase transition in the fluid, resulting in the precipitation of asphaltene material which readily aggregates to the colloidal scale and deposits on metallic surfaces. Colloidal asphaltene deposition in wellbores and pipelines can be especially problematic for industrial purposes, where cleanup processes necessitate costly operational shutdowns. In order to better understand the parametric dependence of deposition which leads to flow blockages, we carry out lab-scale experiments under a variety of material and flow conditions. We develop a parametric scaling model to understand the fluid dynamics and transport considerations governing deposition. The lab-scale experiments are performed by injecting precipitating petroleum fluid mixtures into a small metal pipe, which results in deposition and clogging, assessed by measuring the pressure drop across the pipe. Parametric scaling arguments suggest that the clogging behavior is determined by a combination of the Peclet number, volume fraction of depositing material, and the volume of the injection itself.

  8. Home Automation

    Ahmed, Zeeshan


    In this paper I briefly discuss the importance of home automation system. Going in to the details I briefly present a real time designed and implemented software and hardware oriented house automation research project, capable of automating house's electricity and providing a security system to detect the presence of unexpected behavior.

  9. Characterisation of crude oil components, asphaltene aggregation and emulsion stability by means of near infrared spectroscopy and multivariate analysis

    Aske, Narve


    Effective separation of water-in-crude oil emulsions is a central challenge for the oil industry on the Norwegian Continental Shelf, especially with the future increase in subsea and even down-hole processing of well fluids. The mechanisms and properties governing emulsion stability are far from fully understood but the indigenous surface active crude oil components are believed to play a major role. In this work a thorough physico-chemical characterisation of a set of crude oils originating from a variety of production fields has been performed. Crude oil properties responsible for emulsion stability were identified by use of multivariate analysis techniques like partial least squares regression (PLS) and principal component analysis (PCA). Interfacial elasticity along with both asphaltene content and asphaltene aggregation state were found to be main contributors to emulsion stability. Information on a crude oils ability to form elastic crude oil-water interfaces was found to be especially crucial when discussing emulsion stability. However, measured values of interfacial elasticity were highly dependent on asphaltene aggregation state. Several experimental techniques was utilised and partly developed for the crude oil characterisation. A high-pressure liquid chromatography (HPLC) scheme was developed for SARA-fractionation of crude oils and an oscillating pendant drop tensiometer was used for characterisation of interfacial rheological properties. For emulsion stability a cell for determining the stability as a function of applied electric fields was used. In addition, near infrared spectroscopy (NIR) was used throughout the work both for chemical and physical characterisation of crude oils and model systems. High pressure NIR was used to study the aggregation of asphaltenes by pressure depletion. A new technique for detection of asphaltene aggregation onset pressures based on NIR combined with PCA was developed. It was also found that asphaltene aggregation is

  10. Probing Molecular Interactions of Asphaltenes in Heptol Using a Surface Forces Apparatus: Implications on Stability of Water-in-Oil Emulsions.

    Zhang, Ling; Shi, Chen; Lu, Qingye; Liu, Qingxia; Zeng, Hongbo


    The behaviors and molecular interactions of asphaltenes are related to many challenging issues in oil production. In this study, the molecular interaction mechanism of asphaltenes in Heptol solvents of varying toluene/n-heptane ratio were directly measured using a surface forces apparatus (SFA). The results showed that the interactions between asphaltene surfaces gradually changed from pure repulsion to weak adhesion as the weight ratio of toluene (ω) in Heptol decreased from ω = 1 to 0. The measured repulsion was mainly due to the steric interactions between swelling asphaltene molecules and/aggregates. The micropipet technique was applied to test the stability of two water-in-oil emulsion droplets attached to glass pipettes. A computer-controlled 4-roll mill fluidic device was also built in-house to investigate the interaction of free-suspending water-in-oil emulsions under dynamic flow conditions. Both micropipet and 4-roll mill fluidic tests demonstrate that asphaltenes adsorbed at oil/water interfaces play a critical role in stabilizing the emulsion drops, in agreement with the repulsion measured between asphaltene surfaces in toluene using SFA, and that interfacial sliding or shearing is generally required to destabilize the protective interfacial apshaltene layers which facilitates the coalescence of emulsion drops. Our results provide insights into the fundamental understanding of molecular interaction mechanisms of asphaltenes in organic solvents and stabilization/destabilization behaviors of water-in-oil emulsions with asphaltenes. PMID:27128395

  11. Colloidal analysis of the asphaltene and their fractions with p-nitrophenol (PNP) of the Furrial crude oil for effect of the hydrotreating to different pressures

    Labrador-Sanchez, H. [Univ. de Carabobo, Estado Carabobo (Venezuela, Bolivarian Republic of). Dept. de Quimica, Grupo de Petroleo, Hidrocarburo y Derivados; Lindarte, L. [Univ. de Carabobo, Estado Carabobo (Venezuela, Bolivarian Republic of). Dept. de Quimica, Grupo de Petroleo, Hidrocarburo y Derivados; Univ. de Carabobo, Estado Carabobo (Venezuela, Bolivarian Republic of). Dept. de Quimica, Laboratorio de Catalisis y Metales de Transicion; Luis, M.A. [Univ. de Carabobo, Estado Carabobo (Venezuela, Bolivarian Republic of). Dept. de Quimica, Laboratorio de Catalisis y Metales de Transicion


    A study was conducted to investigate the effect of hydrotreating Furrial crude oil on asphaltene and its fractions (A1 and A2) obtained by the p-Nitrophenol (PNP) method. A batch reactor was used at different pressures of hydrogen to perform 8 hydrotreating reactions on the Furrial crude oil. Asphaltenes were separated from the oil and fractioned with PNP to obtain A1 and A2. The asphaltene and their fractions were characterized for flocculation threshold, percentage of total sulfur, nuclear magnetic resonance of 13C and elemental composition. The study showed that hydrotreating influenced the colloidal behaviour of the asphaltene and that the catalyst promoted the conversion of asphaltene, its stability, and its desulfurization. Hydrotreating had a greater affect on the A2 fraction than the A1 fraction. 2 refs.

  12. A new strategy for the on-column exopeptidase cleavage of poly-histidine tagged proteins.

    Kuo, Wen-Hui K; Chase, Howard A


    This paper describes a new strategy, which aims to make on-column poly-histidine tag removal more useful in the production of recombinant proteins by improving the yield and efficiency of on-column exopeptidase cleavage. This involves improvement of the on-column cleavage condition by using imidazole concentrations in the range of 100-500 mM in the cleavage buffer. At 300 mM imidazole, maximum on-column cleavage yield (in excess of 99%) was achieved in 3h of incubation. However, as a result of the increased imidazole concentration, this new strategy of on-column cleavage results in some residual uncleaved poly-histidine tagged proteins (~0.1%) and the production of cleaved dipeptides, both of which need to be further removed in a subsequent step. A method involving the recirculation of recovered proteins and peptides through the immobilized metal affinity chromatography (IMAC) column (same-column recirculation) was found to be superior to subtractive IMAC for the purpose of contaminant clearance. Recovery of the detagged target proteins was achieved using 10 column volumes of recovery buffer, which had the effect of diluting the imidazole concentration to a suitably low level for contaminant removal by same-column recirculation. This strategy was also applicable at a higher adsorbent loading of 10 mg protein/mL adsorbent with an optimal ratio of 200 mU of DAPase per mg of adsorbed tagged maltose binding protein (MBP), giving a cleavage yield of 99.1% in 3 h. Finally, on-column cleavage conditions including the effect of protease concentration and incubation time on the new strategy have been investigated and comparisons are made for different tag removal strategies. PMID:21925974

  13. Thermogravimetric analysis of petroleum asphaltenes along with estimation of average chemical structure by nuclear magnetic resonance spectroscopy

    Combining with the 1H and 13C nuclear magnetic resonance (NMR) determinations, elemental analysis and molecular weight measurement, average molecular formula of the chemical unit for the asphaltenes from Chinese Daqing crude oil were calculated. Thermal pyrolysis kinetics of the asphaltenes had been studied using thermogravimetric analysis (TGA). The distributed activation energy model (DAEM) was used to analyze these complex systems. The results show that the peak activation energy for pyrolysis of the asphaltenes is 245 kJ mol-1 and the pre-exponential factor is 5.88 x 1014 s-1. The DAEM method presented reasonably good results of the prediction of the weight loss curves. A linear relationship can be found from the plots of logarithm of the pre-exponential factor against the activation energy at selected conversion values. This phenomenon known as the compensation effect was explained and it was in agreement with the estimated chemical structure determined by NMR

  14. Quantitative Determination of Asphaltenes and Resins in Solution by Means of Near-Infrared Spectroscopy. Correlations to Emulsion Stability.

    Kallevik, Harald; Kvalheim, Olav M.; Sjöblom, Johan


    Near-infrared (NIR) spectroscopy in the range 1100-2250 nm together with a latent-variable regression technique is used to analyze the content of asphaltene and resins in solution. It is shown that this technique is capable of determining the amount of these components individually. w/o emulsions were prepared from the separated components of asphaltenes and resins from crude oils. The stability was directly determined with the critical voltage in a dielectric instrumentation. The emulsion stability decreased linearly with an increase in the resin/asphaltene ratio. A final linear model correlating the critical voltage and the analytical concentrations (from the NIR spectra) could be established for this model system. Copyright 2000 Academic Press. PMID:11254289

  15. On the application of NiO nanoparticles to mitigate in situ asphaltene deposition in carbonate porous matrix

    Hashemi, Seyed Iman; Fazelabdolabadi, Babak; Moradi, Siyamak; Rashidi, Ali Morad; Shahrabadi, Abbas; Bagherzadeh, Hadi


    Prevention of asphaltene formation in reservoir rocks can result in resolving a severe long-lasting issue in petroleum production. The present research addresses the issue in the context of exploring the potential effect of nickel oxide (NiO) nanoparticles in destabilizing asphaltene deposition in porous media, in the presence of carbon dioxide. To ensure proper distribution within the system and to retain future field-scale applicability, the NiO nanoparticles were exposed to the in situ oil via injection gas stream, in which they had been uniformly dispersed using polydimethylsiloxane (PDMS). The experimental results, established under miscible CO2 state, indicate a considerable improvement in permeability/porosity reduction of core, as well as less asphaltene accumulation in porous media and increased oil recovery factor after applying NiO nanoparticles.

  16. Library Automation

    Dhakne, B. N.; Giri, V. V; Waghmode, S. S.


    New technologies library provides several new materials, media and mode of storing and communicating the information. Library Automation reduces the drudgery of repeated manual efforts in library routine. By use of library automation collection, Storage, Administration, Processing, Preservation and communication etc.

  17. Process automation

    Process automation technology has been pursued in the chemical processing industries and to a very limited extent in nuclear fuel reprocessing. Its effective use has been restricted in the past by the lack of diverse and reliable process instrumentation and the unavailability of sophisticated software designed for process control. The Integrated Equipment Test (IET) facility was developed by the Consolidated Fuel Reprocessing Program (CFRP) in part to demonstrate new concepts for control of advanced nuclear fuel reprocessing plants. A demonstration of fuel reprocessing equipment automation using advanced instrumentation and a modern, microprocessor-based control system is nearing completion in the facility. This facility provides for the synergistic testing of all chemical process features of a prototypical fuel reprocessing plant that can be attained with unirradiated uranium-bearing feed materials. The unique equipment and mission of the IET facility make it an ideal test bed for automation studies. This effort will provide for the demonstration of the plant automation concept and for the development of techniques for similar applications in a full-scale plant. A set of preliminary recommendations for implementing process automation has been compiled. Some of these concepts are not generally recognized or accepted. The automation work now under way in the IET facility should be useful to others in helping avoid costly mistakes because of the underutilization or misapplication of process automation. 6 figs

  18. Study of flow properties of asphaltenic oils in a porous medium; Etude des proprietes d`ecoulement des bruts asphalteniques en milieu poreux

    Petrova-Bensalem, R.


    Deposits of asphaltenes during production can adversely affect the exploitation of certain fields, that of Hassi Messaoud is a known example. The objective of this study is essentially focused on the damage aspects due to formation of this deposits. A methodology has been developed which makes it possible to determine the flow properties of asphaltenic oils in a porous medium under conditions close to those of a reservoir and to detect the formation of organic deposits in situ. Several types of rocks with different morphology were selected along with a number of asphaltenic oils having varied geographic origins. It was shown with these that it was possible to evaluate, in laboratory, the reduction in permeability to the oil resulting from an asphaltene deposit during the circulation of crude oil in the samples. It was observed that the variation in blocking the cores as a function of the volume of injected fluid is similar to the blocking kinetics ascertained for the retention of solid suspended particles in injection water. This similarity in the phenomena led to using particle damage models developed for the latter case. Several experiments involving blocking by asphaltenes could thus be satisfactory simulated, showing that this approach is worth developing despite the differences between the two types of colloidal suspension. The method using injection or `squeeze` of co- solvents was studied with the same systems (rock/crude oil) as a possible remedy for asphaltene deposition. To select suitable solvents and additives. A methodology was established based on application of Hansen`s theory for adjusting the polarity of solvent to the chemical properties of the asphaltene to be eliminated. This was combined with a series of in vitro tests with separated asphaltenes and the minerals of the reservoir rock. The efficiency of the co-solvents thus selected was verified by slug injection in to cores which has been damaged by asphaltenes. This approach may well help the

  19. Extraction and characterization of crude oil asphaltenes sub fractions; Extracao e caracterizacao de subfracoes de asfaltenos de petroleo

    Ferreira, Silas R.; Calado, Lucas S.; Honse, Siller O.; Mansur, Claudia R.E.; Lucas, Elizabete F., E-mail: [Universidade Federal do Rio de Janeiro, Instituto de Macromoleculas, Laboratorio de Macromoleculas e Coloides na Industria de Petroleo, Rio de Janeiro, RJ (Brazil)


    Asphaltenes from crude oil have been studied for a long time. However, until today their chemical structures and physical-chemical properties are not well established. Nowadays, it is accepted that asphaltenes are dispersed in the crude oil as macro structures, which are mainly constituted of some condensed aromatic rings (about 6-20), containing aliphatic or naphthenic groups. The asphaltenes are also defined as the crude oil fraction that is insoluble in low molar mass n-alkanes and soluble in aromatic solvents, like benzene and toluene In order to investigate the molecular structure, in this work the asphaltenes were separated by using a different procedure as that normally described in the literature and characterized by infrared spectrometry, nuclear magnetic resonance, x-ray fluorescence, elemental analyses and particle size and size distribution. The difference in subfractions polarity can be attributed not only to the aromaticity changes but also to the content of elements, such as N, O, Fe, V, Si e Ni. (author)

  20. Effect of demulsifiers on interfacial films and stability of water-in-oil emulsions stabilized by asphaltenes

    Baydak, E.N.; Yarranton, H.W.; Ortiz, D. [Calgary Univ., AB (Canada). Dept. of Chemical and Petroleum Engineering; Moran, K. [Syncrude Research Centre, Edmonton, AB (Canada)


    In water-in-toluene/heptane emulsions stabilized by asphaltenes, there is a correlation between emulsion stability and the compressibility of interfacial asphaltene films. In order to determine if this correlation for emulsion stability is more generally applicable, a study was conducted in which the effect of commercial demulsifiers on the film properties and emulsion stability was measured. A naphthenic acid (NA) and a branched dodecylbenzene sulfonic acid (DDBS) were examined. Surface pressure isotherms were measured in a drop shape analyzer for droplets of asphaltenes, toluene, and heptane surrounded by a solution of water and surfactant. The experimental variables included heptane, asphaltene and surfactant concentration along with aging time. The compressibilities of the interfacial films were determined from the slope of the surface pressure isotherms. Water-in-oil emulsions were prepared from the same solutions. Emulsion stability was evaluated in terms of the free water evolved after a treatment of centrifugation and heating. Initial results suggest that the demulsifiers increase the compressibility of the interfacial films. In most cases, the addition of the demulsifier increased emulsion stability. The timing of the addition of the demulsifier or the phase to which it was added did not appear to have an influence on the results. It was concluded that the reduction in interfacial tension from the added surfactant may inhibit coalescence more than the weakening of the interfacial film promotes coalescence. 1 ref.

  1. Problematic stabilizing films in petroleum emulsions: shear rheological response of viscoelastic asphaltene films and the effect on drop coalescence.

    Harbottle, David; Chen, Qian; Moorthy, Krishna; Wang, Louxiang; Xu, Shengming; Liu, Qingxia; Sjoblom, Johan; Xu, Zhenghe


    Adsorption of asphaltenes at the water-oil interface contributes to the stability of petroleum emulsions by forming a networked film that can hinder drop-drop coalescence. The interfacial microstructure can either be liquid-like or solid-like, depending on (i) initial bulk concentration of asphaltenes, (ii) interfacial aging time, and (iii) solvent aromaticity. Two techniques--interfacial shear rheology and integrated thin film drainage apparatus--provided equivalent interface aging conditions, enabling direct correlation of the interfacial rheology and droplet stability. The shear rheological properties of the asphaltene film were found to be critical to the stability of contacting drops. With a viscous dominant interfacial microstructure, the coalescence time for two drops in intimate contact was rapid, on the order of seconds. However, as the elastic contribution develops and the film microstructure begins to be dominated by elasticity, the two drops in contact do not coalescence. Such step-change transition in coalescence is thought to be related to the high shear yield stress (~10(4) Pa), which is a function of the film shear yield point and the film thickness (as measured by quartz crystal microbalance), and the increased elastic stiffness of the film that prevents mobility and rupture of the asphaltene film, which when in a solid-like state provides an energy barrier against drop coalescence. PMID:24845467

  2. Three Related FCA Methods for Mining Biclusters of Similar Values on Columns

    Kaytoue, Mehdi; Codocedo, Victor; Baixeries, Jaume; Napoli, Amedeo


    Biclustering numerical data tables consists in detecting particular and strong associations between both subsets of objects and attributes. Such biclusters are interesting since they model the data as local patterns. Whereas there exists several definitions of biclusters, depending on the constraints they should respect, we focus in this paper on biclusters of similar values on columns. There are several ad hoc methods for mining such biclusters in the literature. We focus here on two aspects...

  3. Analysis of metals in asphaltenes of KU-46 by PIXE analysis; Analisis de metales en asfaltenos de crudo mexicano KU-46 por PIXE

    Navidad G, P.; Pina L, L.I.; Lopez M, J.; Ramirez T, J.J.; Aspiazu F, J.A.; Romero G, E.T. [Gerencia de Ciencias Basicas, Instituto Nacional de Investigaciones Nucleares, A.P. 18-1027, 11801 Mexico D.F. (Mexico)


    The content of metals of the asphaltenes obtained from the KU-46 mexican crude with n-heptane was evaluated. The found metals in higher concentration are transition metals as well as the vanadium, nickel, copper and zinc. Moreover the sulfur in high concentrations was quantified. The metallic content of the asphaltenes revealed that the crude contains a lower quantity of metals unlike the vacuum residue previously analysed. (Author)

  4. Effect of Asphaltene Dispersants on Asphaltene Dispersibility in Heavy Fuel Oil%沥青质分散剂对重质燃料油沥青质分散稳定作用研究

    刘新亮; 张菅; 尹海亮


    以总潜在沉淀物为指标,考察了沥青质分散剂对船用燃料油沥青质分散性的影响,并对其分散机理进行了讨论,结果表明,十二烷基苯磺酸、十二烷基苯酚、十二烷基醇和十二烷基胺均对燃料油中的沥青质有一定的分散作用,其中,十二烷基苯磺酸分散性能最好,99%以上的以总潜在沉淀物形式检测到的沥青质可以被其重新分散到燃料油中,其良好的分散性可能与十二烷基苯磺酸分子中的酸性官能团和苯环有关。%The dispersibilities of four different dispersants (dodecylbenzenesulfonic acid,dodecanol,dodecylamine and dodecyl phenol) to asphaltene in heavy fuel oil were evaluated by using the potential total sediment as the index, and the possible dispersing mechanism was discussed. The results show that, dodecylbenzenesulfonic acid has the highest disperability to asphaltene in heavy fuel oil, and more than 99 % asphaltene aggregation can be redispersed when dodecylbenzenesulfonic acid dosage is 4%(wt).

  5. Investigation of the Gas Injection Effect on Asphaltene Onset Precipitation Using the Cubic-Plus-Association Equation of State

    Arya, Alay; von Solms, Nicolas; Kontogeorgis, Georgios M.


    Miscible and immiscible gas flooding is one of the enhanced oil recovery (EOR) techniques that has been widely used to increase the oil production. One of the critical problems with gas flooding is that it generally aggravates the asphaltene precipitation, which further creates a flow assurance...... modeling approach from the previous work and provide the conceptual base for it. Five different reservoir fluids are studied to validate whether the model is able to calculate the effect of different types (e.g., N2, CO2, and methane) and amounts (e.g., 10, 20, and 30 mol %) of gas injections in agreement...... amounts of gas injections and also remains the same at upper and lower onset pressure boundaries. On the basis of this unique characteristic, a simple procedure to predict asphaltene phase envelope (APE) for the reservoir oil with relatively simple and few experimental data, performed on STO with n...

  6. Modeling of asphaltene precipitation due to steam and n-alkane co-injection in the ES-SAGD process

    Badamchizadeh, A.; Kohse, Bruce F.; Kumar, A. [Computer Modelling Group Ltd (Canada)


    This paper provides an insight into the SAGD process in general, and the formation of asphaltene participates in the hybrid ES-SAGD process in particular. The objective of this work was to build an EoS model able to calculate the physical and chemical properties of the bitumen and n-alkane mixture, develop a model to quantify asphaltene participates in bitumen due to n-alkane injection, and investigate their effect on the ES-SAGD process. Athabasca bitumen properties identified under various test conditions and from the results of previous efforts, mainly the SimDist experimental data, were illustrated. These data were used to develop the EoS model, which in turn was used to generate the STARS thermal simulator. Overall, the EoS model was successfully developed and hence was able to predict bitumen and n-heptane properties. Moreover, asphaltene deposition in the ES-SAGD process was modeled in the thermal simulator its effect in causing oil blockage and restrictions in the steam chamber over a long run of the process was demonstrated.

  7. Effect of surfactants on interfacial films and stability of water-in-oil emulsions stabilized by asphaltenes.

    Ortiz, D P; Baydak, E N; Yarranton, H W


    The effect of additives on asphaltene interfacial films and emulsion stability was analyzed through the change in film properties. Surface pressure isotherms were measured at 23°C for model interfaces between aqueous surfactant solutions and asphaltenes dissolved in toluene and heptane-toluene mixtures. Compressibility, crumpling film ratio and surface pressure were determined from the surface pressure isotherms. The stability of water-in-oil emulsions was determined for the same systems based on the proportion of unresolved emulsified water after repeated treatment involving heating at 60°C and centrifugation. Experimental variables included concentration of asphaltenes (5 and 10 kg/m(3)), concentration and type of surfactant (Aerosol OT, nonylphenol ethoxylates, polypropylene oxide block-copolymer, dodecylbenzene sulfonic acids, dodecylbenzene sulfonic acid-polymer blend, diisopropyl naphthalene sulfonic acid, and sodium naphthenate) and aging time (from 10 min to 4 h). Additives were found to have two opposing effects on film properties and emulsion stability: (1) decreasing or eliminating the crumpling ratio which destabilized emulsions and (2) decreasing interfacial tension which enhanced emulsion stability. A stability parameter was defined to include both the crumpling ratio and interfacial tension and provided a consistent correlation for the percent residual emulsified water. PMID:20804982

  8. Characterization of asphaltene molecular structures by cracking under hydrogenation conditions and prediction of the viscosity reduction from visbreaking of heavy oils

    Rueda Velasquez, Rosa Imelda

    The chemical building blocks that comprise petroleum asphaltenes were determined by cracking samples under conditions that minimized alterations to aromatic and cycloalkyl groups. Hydrogenation conditions that used tetralin as hydrogen-donor solvent, with an iron-based catalyst, allowed asphaltenes from different geological regions to yield 50-60 wt% of distillates (Paraffins and 1-3 ring aromatics were the most abundant building blocks. The diversity of molecules identified, and the high yield of paraffins were consistent with high heterogeneity and complexity of molecules, built up by smaller fragments attached to each other by bridges. The sum of material remaining as vacuum residue and coke was in the range of 35-45 wt%; this total represents the maximum amount of large clusters in asphaltenes that could not be converted to lighter compounds under the evaluated cracking conditions. These analytical data for Cold Lake asphaltenes were transformed into probability density functions that described the molecular weight distributions of the building blocks. These distributions were input for a Monte Carlo approach that allowed stochastic construction of asphaltenes and simulation of their cracking reactions to examine differences in the distributions of products associated to the molecular topology. The construction algorithm evidenced that a significant amount of asphaltenes would consist of 3-5 building blocks. The results did not show significant differences between linear and dendritic molecular architectures, but suggested that dendritic molecules would experience slower reaction rates as they required more breakages to reach a given yield of distillates. Thermal cracking of asphaltenes in heavy oils and bitumens can dramatically reduce viscosity, enabling pipeline transportation with less solvent addition. The viscosities of the products from visbreaking reactions of two different heavy oils were modeled with lumped kinetics based on boiling point pseudo

  9. Automation Security

    Mirzoev, Dr. Timur


    Web-based Automated Process Control systems are a new type of applications that use the Internet to control industrial processes with the access to the real-time data. Supervisory control and data acquisition (SCADA) networks contain computers and applications that perform key functions in providing essential services and commodities (e.g., electricity, natural gas, gasoline, water, waste treatment, transportation) to all Americans. As such, they are part of the nation s critical infrastructu...

  10. Mise en évidence de la polydispersité physico-chimique des asphaltènes Evidence of the Physicochemical Polydispersity of Asphaltenes

    Szewczyk V.


    Full Text Available Afin d'élaborer un modèle thermodynamique capable de décrire la floculation des asphaltènes en s'appuyant au maximum sur la réalité physicochimique, nous nous sommes efforc In order to develop a thermodynamic model able to describe the flocculation of asphaltenes according to their physicochemical properties, we have tried to give a better definition of the asphaltenes chemical structure and to show its influence on the mechanism of aggregation in solution. This work consisted in :- putting in evidence the physical and chemical polydispersity of asphaltenes;- studying simultaneously the nature and the localization of the chemical functions in the asphaltene oligomers (elemental analysis, analysis of the pyrolysed products, etc. and their capacity to aggregate in solution (X-ray diffusion to better understand the aggregation mechanims and to identify the functions responsible of this aggregation;- establishing a relation between the proportion of these functions and the size of the aggregates in order to take it in account in the thermodynamic model.The fractionation of a sample of asphaltenes with increasing quantities of n-heptane has allowed to separate different classes of aggregates. For each added quantity of n-heptane, the sample of asphaltenes has been separated in an insoluble fraction and a soluble one. The insoluble fraction contains the aggregates which firstly floculate. The elemental composition of each fraction has been determined by elemetal analysis. The pyrolysis in an open medium has allowed to break the aggregates in elementary patterns, the nature of the different patterns has been determined by liquid and gazeous chromatography. The size of the aggregates has been observed by X-ray diffusion.The results of this chemical characterization have shown that the initial sample of asphaltenes is formed by a group of oligomers having different elemental compositions and different chemical structures. The aggregates which

  11. Asphaltenes analysis arising of non conventional oils; Analise de asfaltenos oriundos de petroleos nao convencionais

    Silva, Fernanda B. da; Fiorio, Paula G.P.; Guimaraes, Maria Jose O.C.; Seidl, Peter R. [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Escola de Quimica


    The need to use heavy fractions in an efficient way in the production of nobler fractions has motivated the search for ways of separating the asphaltenes, since these molecules increase the viscosity of the fractions submitted to distillation, contribute to the formation of coke and to poisoning and deactivation of catalysts used in process such as cracking, reform, etc, besides provoking cloggings and blockages caused by its deposition, generating losses on the productivity and increases of the operational costs. This paper evaluates the influence of solvent blends (EQ-NP) in the selective extraction of constituents of three samples from Brazilian heavy crude. For the extraction process was used two solvent blends (N1P1 and N1P2). The solvent blend composed of N1P1 showed a higher selectivity in the extraction of aggregates than N1P2. The extracted fraction was characterized by Hydrogen Nuclear Magnetic Resonance ({sup 1}H-NMR) and revealed that the chemical species extracted from different blends exhibit very small differences. (author)

  12. Automated Budget System

    Department of Transportation — The Automated Budget System (ABS) automates management and planning of the Mike Monroney Aeronautical Center (MMAC) budget by providing enhanced capability to plan,...

  13. Steroid-Derived Naphthoquinoline Asphaltene Model Compounds: Hydriodic Acid Is the Active Catalyst in I2-Promoted Multicomponent Cyclocondensation Reactions.

    Schulze, Matthias; Scott, David E; Scherer, Alexander; Hampel, Frank; Hamilton, Robin J; Gray, Murray R; Tykwinski, Rik R; Stryker, Jeffrey M


    A multicomponent cyclocondensation reaction between 2-aminoanthracene, aromatic aldehydes, and 5-α-cholestan-3-one has been used to synthesize model asphaltene compounds. The active catalyst for this reaction has been identified as hydriodic acid, which is formed in situ from the reaction of iodine with water, while iodine is not a catalyst under anhydrous conditions. The products, which contain a tetrahydro[4]helicene moiety, are optically active, and the stereochemical characteristics have been examined by VT-NMR and VT-CD spectroscopies, as well as X-ray crystallography. PMID:26584791

  14. N(pro) fusion technology: On-column complementation to improve efficiency in biopharmaceutical production.

    Schindler, S; Missbichler, B; Walther, C; Sponring, M; Cserjan-Puschmann, M; Auer, B; Schneider, R; Dürauer, A


    N(pro) fusion technology, a highly efficient system for overexpression of proteins and peptides in Escherichia coli, was further developed by splitting the autoprotease N(pro) into two fragments to generate a functional complementation system. The size of the expression tag is thus reduced from 168 to 58 amino acids, so by 66%. Upon complementation of the fragments auto-proteolytic activity is restored. This process has been shown for three model proteins of different size, a short 16 aa-peptide, MCP-1, and lysozyme. Moreover, the complementation was still functional after immobilization of the N-terminal fragment to a solid support which enables recycling of the immobilized fragment. This strategy enhances overall productivity of N(pro) Fusion Technology and thus allows more efficient production of recombinant proteins with reduced costs and in higher yields. Overall, the N(pro) complementation system has, depending on the size of the target molecule, potential to increase the productivity up to 4 fold for batch refolding and even more for on-column refolding strategies by the proven possibility of regeneration of the immobilized fragment. PMID:26687898

  15. Manufacturing and automation

    Ernesto Córdoba Nieto


    The article presents concepts and definitions from different sources concerning automation. The work approaches automation by virtue of the author’s experience in manufacturing production; why and how automation prolects are embarked upon is considered. Technological reflection regarding the progressive advances or stages of automation in the production area is stressed. Coriat and Freyssenet’s thoughts about and approaches to the problem of automation and its current state are taken and e...

  16. Do column frits contribute to the on-column, flow-induced degradation of macromolecules?

    Striegel, André M


    Flow-induced, on-column degradation is a major hindrance to the accurate characterization of ultra-high molar mass macromolecules and colloids. This degradation is a direct result of the large shear rates which are generated within the column, which cause chain scission to occur both in the interstitial medium and, it has been postulated, at the packing particle pore boundary. An additional putative source of degradation has been the column frits, though little experimental evidence exists to either support or refute this claim. To this effect, the present experiments examine the role of the frits in the degradation of high molar mass macromolecules. Two narrow dispersity polystyrene standards, the molar mass of which differs by a factor of two, were analyzed on three different size-exclusion chromatography (SEC) columns, each with frits of different pore size, at various flow rates. In the smallest pore size column, which also contained the smallest frits and which was packed with the smallest diameter particles, the larger standard was forced to degrade by increasing the flow rate of the mobile phase. During the course of the latter portion of the study, the inlet and the outlet frits were removed from the column, in stepwise fashion. It was concluded that neither frit played any appreciable role in the degradation. Results of our studies were applied to explain previously observed degradation in ultra-high pressure liquid chromatography of polymers. The general conclusion arrived at herein is that the column frits are likely to have a secondary role (as compared to interstitial and pore boundary stresses), or no role at all, in polymer degradation for cases where the frit radius is larger than or equal to the hydraulic radius rcof the column. PMID:25085820

  17. Techniques for monitoring fouling tendency resulting from thermal treatment

    Schabron, J.F.; Rovani, J.F. [United States Dept. of Energy, Laramie, WY (United States). Western Research Inst.


    Western Research Institute (WRI) coking index calculations use analyses derived from various stages of pyrolysis. Pyrolsis severity is monitored using automated flocculation titrimetry (AFT) and ultrasonic spectroscopy. AFT data are then used to to calculate various stability and solubility parameters. Ultrasonic amplitude and frequency spectra of residua exhibit maximum intensities near 1.1 MHz and diminish during the initial stages of pyrolysis, then grown again as pre-coke materials form. As pyrolysis progresses, the amount of heptane asphaltenes soluble in cyclohexane decreases as coke and toluene insoluble (TI) pre-coke materials appear. While automated flocculation titrimetry (AFT) and ultrasonic spectroscopy can be used to calculate the various stability and solubility parameters, analysis can take up to 3 days to perform. This presentation provided details of a novel automated on-column asphaltene precipitation and re-dissolution technique to isolate heptane asphaltenes and determine the amount of asphaltenes soluble in cyclohexane. Oil solution is injected onto a packed column with a heptane mobile phase. Asphaltene material is re-dissolved in a step gradient sequence of 4 solvents: heptane; cyclohexane; toluene; and methylene chloride. The sequence is followed by a polytetrafluoroethylene (PTFE) stationary phase. Experiments with the method indicated that greater accuracy in the distribution and amounts of polar materials were observed than with gravimetric asphaltene analysis. It was concluded that the automated technique provides a sensitive diagnosis of the pyrolysis severity history of a residuum. refs., tabs., figs.

  18. Far- and mid-infrared spectroscopy of complex organic matter of astrochemical interest: coal, heavy petroleum fractions, and asphaltenes

    Cataldo, F; Manchado, A


    The coexistence of a large variety of molecular species (i.e., aromatic, cycloaliphatic and aliphatic) in several astrophysical environments suggests that unidentified IR emission (UIE) occurs from small solid particles containing a mix of aromatic and aliphatic structures (e.g., coal, petroleum, etc.), renewing the astronomical interest on this type of materials. A series of heavy petroleum fractions namely DAE, RAE, BQ-1, and asphaltenes derived from BQ-1 were used together with anthracite coal and bitumen as model compounds in matching the band pattern of the emission features of proto-planetary nebulae (PPNe). All the model materials were examined in the mid-infrared (2.5-16.7 um) and for the first time in the far-infrared (16.7-200 um), and the IR bands were compared with the UIE from PPNe. The best match of the PPNe band pattern is offered by the BQ-1 heavy aromatic oil fraction and by its asphaltenes fraction. Particularly interesting is the ability of BQ-1 to match the band pattern of the aromatic-ali...

  19. Chemical modification of a bitumen and its non-fuel uses. [Reactions of tar sand asphaltenes in synthesis of non-fuel products

    Moschopedis, S.E.; Speight, J.G.


    Simple reactions are described whereby tar sand bitumen can be converted to a whole range of materials. Examples are given to illustrate the non-fuel uses of the products. The following reactions of Athabasca asphaltenes are considered: oxidation, halogenation, sulfonation and sulfomethylation, phosphorylation, hydrogenation, reactions with S and O, reactions with metal salts, and miscellaneous chemical conversions. (JGB)

  20. Combustion of drops of Mexican fuel oils with high asphaltenes content; Combustion de gotas de combustoleos mexicanos con alto contenido de asfaltenos

    Garcia Rodriguez, Jose Francisco [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)


    In this work the combustion of fuel drops with a content of 18% of asphaltenes has been studied . The results obtained for this fuel were compared with the ones obtained for another with a content of 12% asphaltenes. The drops were suspended in a platinum filament and burned in an spherical radiant furnace. The drop size varied between 600 and 800 microns. The fuel drops with 12% asphaltenes showed shorter combustion times, a smaller diameter increment of the smaller diameter during the combustion stages and also a shorter burning time of the carbonaceous residue than the fuel drops with a content of 18% asphaltenes. [Espanol] En el presente trabajo se ha estudiado la combustion de gotas de combustible con 18% de contenido de asfaltenos. Los resultados obtenidos para este combustible se compararon con los obtenidos para otro con 12% de contenido de asfaltenos. Las gotas fueron suspendidas en un filamento de platino y quemadas en un horno radiante esferico. El tamano de las gotas vario entre 600 y 800 micras. Las gotas de combustible con 12% de asfaltenos mostraron tiempos de combustion mas cortos, un incremento del diametro menor durante las etapas de combustion y un tiempo de quemado del residuo carbonoso tambien mas corto que las gotas del combustible con 18% de contenido de asfaltenos.

  1. A small angle neutron scattering study of the adsorbed asphaltene layer in water-in-hydrocarbon emulsions: structural description related to stability.

    Jestin, Jacques; Simon, Sébastien; Zupancic, Lina; Barré, Loïc


    We have developed a specific protocol to study with SANS measurements, the structure of the interfacial film layer in water-in-oil emulsions stabilized by asphaltene. Using the contrast matching technique available for neutron scattering, we have access to both the composition and the quantity of interface. The results obtained give us a view of the asphaltene aggregates in the interfacial film, which are structured as a monolayer and show a direct correlation between the size of asphaltene aggregates in solution and the thickness of the film layer. The organization of the interface has been studied as a function of several parameters such as the quantity of resins, i.e., the size of aggregates, the pH of the aqueous phase, and the aging time of the emulsions and the consequences of these variations on the macroscopic stability of these emulsions. We show that the key parameter for the stability is the inter-asphaltene aggregate interaction inside the film layer. Changing the attractive/repulsive balance between the aggregates in the film at the microscopic scale, by changing the aggregate's size or the aggregate's ionization, has a direct incidence on the quantity of water recovered after centrifugation: the stronger the attraction between aggregates in the film, the more stable the emulsion is. PMID:17867712

  2. Probing the Carbonyl Functionality of a Petroleum Resin and Asphaltene through Oximation and Schiff Base Formation in Conjunction with N-15 NMR.

    Kevin A Thorn

    Full Text Available Despite recent advances in spectroscopic techniques, there is uncertainty regarding the nature of the carbonyl groups in the asphaltene and resin fractions of crude oil, information necessary for an understanding of the physical properties and environmental fate of these materials. Carbonyl and hydroxyl group functionalities are not observed in natural abundance 13C nuclear magnetic resonance (NMR spectra of asphaltenes and resins and therefore require spin labeling techniques for detection. In this study, the carbonyl functionalities of the resin and asphaltene fractions from a light aliphatic crude oil that is the source of groundwater contamination at the long term USGS study site near Bemidji, Minnesota, have been examined through reaction with 15N-labeled hydroxylamine and aniline in conjunction with analysis by solid and liquid state 15N NMR. Ketone groups were revealed through 15N NMR detection of their oxime and Schiff base derivatives, and esters through their hydroxamic acid derivatives. Anilinohydroquinone adducts provided evidence for quinones. Some possible configurations of the ketone groups in the resin and asphaltene fractions can be inferred from a consideration of the likely reactions that lead to heterocyclic condensation products with aniline and to the Beckmann reaction products from the initially formed oximes. These include aromatic ketones and ketones adjacent to quaternary carbon centers, β-hydroxyketones, β-diketones, and β-ketoesters. In a solid state cross polarization/magic angle spinning (CP/MAS 15N NMR spectrum recorded on the underivatized asphaltene as a control, carbazole and pyrrole-like nitrogens were the major naturally abundant nitrogens detected.

  3. Rheological properties of hydrate suspensions in asphaltenic crude oils; Proprietes rheologiques de suspensions d'hydrate dans des bruts asphalteniques

    Marques de Toledo Camargo, R.


    The development of offshore oil exploitation under increasing water depths has forced oil companies to increase their understanding of gas hydrate formation and transportation in multiphase flow lines in which a liquid hydrocarbon phase is present. This work deals with the flow behaviour of hydrate suspensions in which a liquid hydrocarbon is the continuous phase. Three different liquid hydrocarbons are used: an asphaltenic crude oil, a condensate completely free of asphaltenes and a mixture between the asphaltenic oil and heptane. The rheological characterisation of hydrate suspensions is the main tool employed. Two original experimental devices are used: a PVT cell adapted to operate as a Couette type rheometer and a semi-industrial flow loop. Hydrate suspensions using the asphaltenic oil showed shear-thinning behaviour and thixotropy. This behaviour is typically found in flocculated systems, in which the particles attract each other forming flocs of aggregated particles at low shear rates. The suspensions using the condensate showed Newtonian behaviour. Their relative viscosities were high, which suggests that an aggregation process between hydrate particles takes. place during hydrate formation. Finally, hydrate suspensions using the mixture asphaltenic oil-heptane showed shear-thinning behaviour, thixotropy and high relative viscosity. From these results it can be inferred that, after the achievement of the hydrate formation process, the attractive forces between hydrate particles are weak. making unlikely pipeline obstruction by an aggregation process. Nevertheless, during the hydrate formation, these attractive forces can be sufficiently high. It seems that the hydrate surface wettability is an important parameter in this phenomena. (author)

  4. Manufacturing and automation

    Ernesto Córdoba Nieto


    Full Text Available The article presents concepts and definitions from different sources concerning automation. The work approaches automation by virtue of the author’s experience in manufacturing production; why and how automation prolects are embarked upon is considered. Technological reflection regarding the progressive advances or stages of automation in the production area is stressed. Coriat and Freyssenet’s thoughts about and approaches to the problem of automation and its current state are taken and examined, especially that referring to the problem’s relationship with reconciling the level of automation with the flexibility and productivity demanded by competitive, worldwide manufacturing.

  5. An efficient on-column expressed protein ligation strategy: Application to segmental triple labeling of human apolipoprotein E3

    Zhao, Wentao; Zhang, Yonghong; Cui, Chunxian; Li, Qianqian; Wang, Jianjun


    Expressed protein ligation (EPL) is an intein-based approach that has been used for protein engineering and biophysical studies of protein structures. One major problem of the EPL is the low yield of final ligation product, primarily due to the complex procedure of the EPL, preventing EPL from gaining popularity in the research community. Here we report an efficient on-column EPL strategy, which focuses on enhancing the expression level of the intein-fusion protein that generates thioester fo...

  6. An automated swimming respirometer



    An automated respirometer is described that can be used for computerized respirometry of trout and sharks.......An automated respirometer is described that can be used for computerized respirometry of trout and sharks....

  7. Configuration Management Automation (CMA)

    Department of Transportation — Configuration Management Automation (CMA) will provide an automated, integrated enterprise solution to support CM of FAA NAS and Non-NAS assets and investments. CMA...

  8. Workflow automation architecture standard

    Moshofsky, R.P.; Rohen, W.T. [Boeing Computer Services Co., Richland, WA (United States)


    This document presents an architectural standard for application of workflow automation technology. The standard includes a functional architecture, process for developing an automated workflow system for a work group, functional and collateral specifications for workflow automation, and results of a proof of concept prototype.

  9. Géochimie des résines et asphaltènes Geochernistry of Resins and Asphaltenes

    Tissot B.


    Full Text Available Les produits lourds des huiles brutes (résines et asphaltènes jouent un rôle important dans la genèse et l'accumulation du pétrole, ainsi que dans la mise en production par des méthodes conventionnelles ou par récupération assistée. Les asphaltènes et résines sont considérés ici comme des fragments de kérogène, avec une structure d'ensemble comparable : ils peuvent constituer des intermédiaires dans la genèse de l'huile brute par dégradation thermique du kérogène. De plus, la pyrolyse des asphaltènes séparés à partir d'un pétrole biodégradé peut produire de nouveaux hydrocarbures saturés qui reproduisent la fraction saturée primitive, détruite par la dégradation ; on peut ainsi disposer d'un nouvel outil pour corréler ce type d'huiles brutes. Les produits lourds semblent défavorisés par rapport aux hydrocarbures, dans la migration de la roche-mère vers le réservoir, où les résines et asphaltènes sont proportionnellement moins abondants. La structure physique des asphaltènes et résines dans les pétroles, et en particulier l'existence d'une macrostructure du type micelles ou agrégats, est probablement responsable de la viscosité élevée des huiles lourdes. Une meilleure connaissance de cette macrostructure pourrait suggérer de nouvelles méthodes pour diminuer la viscosité et améliorer la récupération des huiles lourdes. The heavy constituents of crude oil (resins and asphaltenes play an important role in generation and accumulation of petroleum, and also in production by conventional and enhanced oil recovery processes. Asphaltenes and resins are considered here as small fragments of kerogen, with a comparable overall structure: they may act as intermediate compounds in oil generation by thermal breakdown of kerogen. Furthermore, pyrolysis of asphaltenes separated from a degraded crude oil is able to generate a new saturated hydrocarbon fraction which duplicates the original one, now degraded

  10. Effect of asphaltene and resin oils on the viscosity of bituminous petroleum materials to be used as asphalt primers

    Bencomo, M. R.


    Full Text Available The bituminous crude from the Machete, Venezuela, area, which has such a fluid consistency that it falls outside the normal scope of the A5TM D-5 (1 penetration test exceeding the 3D-mm ceiling specified in that standard and can be used as an asphalt primer: Like other asphalt products, these materials are -chemically speaking- a mix of numerous naphthenic, paraffinic and aromatic hydrocarbons and heterocyclic compounds containing sulphur, nitrogen, oxygen and so on. They have a dense and a malthene oil phase which, along with the natural hydrocarbons additives used in these products acts as a volatile fluidizer. The former is described as a mix of asphaltenes: complex high molecular weight substances that are insoluble in paraffinic hydrocarbons and soluble in aromatic compounds such as benzene. The malthene oil phase, in turn, consists in a mix of resins and hydrocarbons and together the two constitute a colloidal system. The experiments discussed in the present paper were conducted to determine the effect of the proportion of asphaltenes and resin oils on the viscosity of such bituminous crude emulsions/ with a view to their use as primers. These experiments were run in a Parr batch reactor in a nitrogen atmosphere using n-heptane as a solvent. The resins were separated after the asphaltenes precipitated from the samples and subsequently from the malthene fraction obtained. The results showed that the asphaltenes account for the structural characteristics and consistency of the medium and the resin oils for its cohesive properties/,the malthene oils act as solvents.Los crudos extrapesados procedentes del área Machete (Venezuela son materiales de consistencia blanda o fluida, por lo que se salen del campo en el que normalmente se aplica el ensayo de penetración a productos asfálticos según el método ASTM D-5 (1, cuyo límite máximo es 30 mm, y pueden ser utilizados como pinturas asfálticas de imprimación. Al igual que otros productos


    Facelli, Julio; Pugmire, Ronald; Pimienta, Ian


    The goal of this project is to obtain and validate three dimensional atomistic models for the organic matter in both oil shales and oil sands. In the case of oil shales the modeling was completed for kerogen, the insoluble portion of the organic matter; for oil sands it was for asphaltenes, a class of molecules found in crude oil. The three dimensional models discussed in this report were developed starting from existing literature two dimensional models. The models developed included one kerogen, based on experimental data on a kerogen isolated from a Green River oil shale, and a set of six representative asphaltenes. Subsequently, the interactions between these organic models and an inorganic matrix was explored in order to gain insight into the chemical nature of this interaction, which could provide vital information in developing efficient methods to remove the organic material from inorganic mineral substrate. The inorganic substrate used to model the interaction was illite, an aluminum silicate oxide clay. In order to obtain the feedback necessary to validate the models, it is necessary to be able to calculate different observable quantities and to show that these observables both reproduce the results of experimental measurements on actual samples as well as that the observables are sensitive to structural differences between models. The observables that were calculated using the models include 13C NMR spectra, the IR vibrational spectra, and the atomic pair wise distribution function; these were chosen as they are among the methods for which both experimental and calculated values can be readily obtained. Where available, comparison was made to experiment results. Finally, molecular dynamic simulations of pyrolysis were completed on the models to gain an understanding into the nature of the decomposition of these materials when heated.

  12. Brewster angle microscopy of Langmuir films of athabasca bitumens, n-C5 asphaltenes, and SAGD bitumen during pressure-area hysteresis.

    Hua, Yujuan; Angle, Chandra W


    Bitumen films formed on water surfaces have negative consequences, both environmental and economic. CanmetENERGY has placed considerable research emphasis on understanding the structures of the bitumen films on water as a necessary step before optimization of bitumen extraction. The detailed structures of the adsorbed molecules and, especially, the role of asphaltene molecules at the interfaces are still under scrutiny and debate. In the present study, we compared bitumen and asphaltene films as they were compressed and expanded under various surface pressures in order to achieve a clearer understanding of bitumen film structures. We used a customized NIMA Langmuir trough interfaced to a Brewster angle microscope (BAM) and CCD camera (Nanofilm_ep3BAM, Accurion, previously Nanofilm Gmbh) to study images of bitumen films at the air/water interface. The bitumen film appeared uniform with high reflectivity at a surface pressure of 18 mN·m(-1) and exhibited a coarse pebblelike interface with reduced reflectivity in the liquid condensed (LC) phase at higher pressures (18-35 mN·m(-1)). During the first cycle of compression asphaltene films showed well-defined phase transitions and a uniformly smooth interface in the LC phase between 9 and 35 mN·m(-1). However, folding or buckling occurred at surface pressures from 35 to 44 mN·m(-1). On expansion, asphaltene films appeared to break into islands. The hysteresis of the pressure-area isotherm was much larger for asphaltenes than for bitumen. In both compression and expansion cycles, BAM images for bitumen films appeared to be more reproducible than those of the asphaltene films at the same surface pressures. Films for low-°API SAGD bitumen were almost identical to those for surface-mined bitumen. Films formed from partially deasphalted surface-mined bitumens showed higher compressibility and lower rigidity than the original bitumen. The BAM images illustrated significant differences between the partially deasphalted and

  13. Shoe-String Automation

    Duncan, M.L.


    Faced with a downsizing organization, serious budget reductions and retirement of key metrology personnel, maintaining capabilities to provide necessary services to our customers was becoming increasingly difficult. It appeared that the only solution was to automate some of our more personnel-intensive processes; however, it was crucial that the most personnel-intensive candidate process be automated, at the lowest price possible and with the lowest risk of failure. This discussion relates factors in the selection of the Standard Leak Calibration System for automation, the methods of automation used to provide the lowest-cost solution and the benefits realized as a result of the automation.

  14. Avaliação geoquímica de biomarcadores ocluídos em estruturas asfaltênicas Geochemical evaluation of occluded biomarkers in asphaltenic structures

    Débora de Almeida Azevedo


    Full Text Available Asphaltenes from two Brazilian crude oils were submitted to mild oxidation to disrupt their structure, releasing the occluded oil. The released hydrocarbons were compared with those from the original crude oil, and used to evaluate the alteration of the oils, especially as a result of biodegradation, but also thermal maturity. The crude oils used are depleted in n-alkanes, which are usually related to biodegradation. However, the released products from the corresponding asphaltenes have n-alkane distributions from nC10 to nC40, suggesting a protection effect from biodegradation. The m/z 191 mass chromatograms showed higher relative intensities for tricyclic terpanes than the hopanes in the crude in comparison with the released ones.

  15. Improved automated synthesis and preliminary animal PET/CT imaging of 11C-acetate

    To study a simple and rapid automated synthetic technology of 11C-acetate (11C- AC), automated synthesis of 11C-AC was performed by carboxylation of MeMgBr/tetrahydrofuran (THF) on a polyethylene loop with 11C-CO2, followed by hydrolysis and purification on solid-phase extraction cartridges using a 11C-Choline/Methionine synthesizer made in China. A high and reproducible radiochemical yield of above 40% (decay corrected) was obtained within the whole synthesis time about 8 min from 11C-CO2. The radiochemical purity of 11C-AC was over 95%. The novel, simple and rapid on-column hydrolysis-purification procedure should adaptable to the fully automated synthesis of 11C-AC at several commercial synthesis module. 11C-AC injection produced by the automated procedure is safe and effective, and can be used for PET imaging of animals and humans. (authors)

  16. Ruthenium-ion-catalyzed oxidation of asphaltenes and oil-source correlation of heavy oils from the Lunnan and Tahe oilfields in the Tarim Basin, NW China

    MA Anlai; ZHANG Shuichang; ZHANG Dajiang; JIN Zhijun; MA Xiaojuan; CHEN Qingtang


    The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphaltenes in heavy oils from the Lunnan and Tahe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations. The RICO products included n-alkanoic acids, α, ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid , regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields are different from those of Well TD2. The biomarkers bounded on the asphaltenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C2s sterane and C29 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tahe oilfields.

  17. Effect of various catalysts on the chemical structure of oils and asphaltenes obtained from the hydroliquefaction of a highly volatile bituminous coal

    Cebolla, V.L.; Diack, M.; Oberson, M.; Bacaud, R.; Cagniant, D.; Nickel-Pepin-Donat, B. (Universite de Metz, Metz (France))


    The catalysts studied were aerosols of SiO{sub 2}, Fe{sub 2}O{sub 3}, MoO{sub 3} and Ni-Mo/Al{sub 2}O{sub 3}. The hydroliquefaction runs at 350, 400 and 430{degree}C, in the presence of tetralin and sulfur, were evaluated by solvent extractions, hydrogen consumption and structural analysis of the isolated oil and asphaltene fractions. At 350 {degree}C, a clear influence of the catalyst on the extraction yields is observed. This effect disappears at higher temperatures. Nevertheless, hydrogen consumption from gas or solvent is affected by the nature of the catalyst at a given temperature. The influence of the catalyst is also confirmed by electron spin resonance study of the stable radicals of the tetrahydrofuran insoluble fractions. After elimination of tetralin, the structural analyses were carried out by gas chromatography (oils), size exclusion chromatography (oils and asphaltenes) and extrography (raw hydroliquefaction products). The oils obtained with sulfided Fe{sub 2}O{sub 3} or MoO{sub 3} contained significantly more two-ringed aromatic compounds than oils obtained with the other catalysts or without added catalyst. No significant influence of the catalyst at a given temperature on the oils and asphaltenes is observed by size exclusion chromatography. In contrast, a large temperature effect is evidenced for each fraction, independently of the nature of the catalyst. 38 refs., 7 figs., 6 tabs.

  18. Effect of salts on the interfacial tension of asphaltene-toluene/water interface : prediction by Poisson-Boltzmann modified model and experimental validation

    Se, R.A.G.; Lima, E.R.A.; Nele, M.; Tavares, F.W. [Federal Univ. of Rio de Janeiro (Brazil). School of Chemistry; Bostrom, M. [Linkoping Univ., Linkoping (Sweden). Dept. of Physics, Chemistry and Biology


    This study presented new experimental data of interfacial tension of toluene-asphaltene/water systems in the presence of different salts. In order to study the stability of emulsions caused by the presence of salts in produced water, it is important to understand the interaction of ions at the interface. It was simpler to use model systems consisting of asphaltenes dissolved in toluene because of the complexity of the interfacially active components in oil. The study involved a Brazilian crude oil in which asphaltene was precipitated with a 1:15 ratio of n-heptane and solutions of water with salts LiCl, KCl, NaCl, NaI, NaBr and KBr in concentrations of 0.10, 0.25, 0.50, 0.75 and 1.0 M. The study investigated salt mixtures NaCl/NaBr and NaCl/NaI in the proportions 0.8:0.2, 0.6:0.4, 0.4:0.6, 0.2:0.8 molar. The experimental data was modeled using a modified Poisson-Boltzmann equation that considered dispersion in order to take into account the influence of ions at the interface.

  19. Automated stopcock actuator

    Vandehey, N. T.; O'Neil, J.P.


    Introduction We have developed a low-cost stopcock valve actuator for radiochemistry automation built using a stepper motor and an Arduino, an open-source single-board microcontroller. The con-troller hardware can be programmed to run by serial communication or via two 5–24 V digital lines for simple integration into any automation control system. This valve actuator allows for automated use of a single, disposable stopcock, providing a number of advantages over stopcock manifold systems ...

  20. The Adaptive Automation Design

    Calefato, Caterina; Montanari, Roberto; TESAURI, Francesco


    After considering the positive effects of adaptive automation implementation, this chapter focuses on two partly overlapping phenomena: on the one hand, the role of trust in automation is considered, particularly as to the effects of overtrust and mistrust in automation's reliability; on the other hand, long-term lack of exercise on specific operation may lead users to skill deterioration. As a future work, it will be interesting and challenging to explore the conjunction of adaptive automati...

  1. Service functional test automation

    Hillah, Lom Messan; Maesano, Ariele-Paolo; Rosa, Fabio; Maesano, Libero; Lettere, Marco; Fontanelli, Riccardo


    This paper presents the automation of the functional test of services (black-box testing) and services architectures (grey-box testing) that has been developed by the MIDAS project and is accessible on the MIDAS SaaS. In particular, the paper illustrates the solutions of tough functional test automation problems such as: (i) the configuration of the automated test execution system against large and complex services architectures, (ii) the constraint-based test input generation, (iii) the spec...

  2. Re-Os dating of maltenes and asphaltenes within single samples of crude oil

    Georgiev, Svetoslav V.; Stein, Holly J.; Hannah, Judith L.; Galimberti, Roberto; Nali, Micaela; Yang, Gang; Zimmerman, Aaron


    Re-Os geochronology of oil may constrain the timing of oil formation and improve oil-source and oil-oil correlations. Typically, asphaltene (ASPH), the heaviest and most Re-Os rich oil fraction, from multiple oils within an oil field or a larger petroleum system are analyzed to obtain sufficient spread in Re-Os isotopic ratios, a mathematical necessity for precise Re-Os isochrons. Here we offer a new approach for Re-Os geochronology of oil based on isotopic analyses of different fractions within a single sample of crude oil. We studied three oils from the Gela oil field, southern Sicily, Italy, recovered from Triassic-Jurassic stratigraphic intervals (Streppenosa, Noto, and Sciacca Formations) within the Gela-1 well. ASPH (insoluble in n-alkane) and maltene (MALT, soluble in n-alkane) fractions of oil were separated using n-pentane, n-hexane, n-heptane and n-decane solvents. The ASPH contents of the Sciacca and Noto oils (26-33 wt%) are notably higher compared to the Streppenosa oil (7-12 wt% ASPH). We present an optimized Re-Os procedure with sample digestion in a high-pressure asher, followed by isotopic measurements using negative thermal ionization mass spectrometry. Very high metal contents of Gela oils allowed acquisition of precise Re-Os data. Systematic variations between the type of solvent used for ASPH precipitation and the ASPH content of the oil (also known from the literature) and the Re-Os contents of the ASPH and MALT fractions (first observed in this study) provide important practical applications for Re-Os analyses of oil. Most Re and Os (∼96-98%) in the Noto oil are hosted in the ASPH fraction. In contrast, a significant portion of Re and Os (∼33-34%) is stored in the MALT fraction of the lighter, but heavily biodegraded Streppenosa oil. Collectively, our new data on alkane distribution, hopane and sterane biomarkers, major and trace element contents, and Re-Os concentrations and isotopic ratios of the oils and their fractions support the

  3. Automated Weather Observing System

    Department of Transportation — The Automated Weather Observing System (AWOS) is a suite of sensors, which measure, collect, and disseminate weather data to help meteorologists, pilots, and flight...

  4. Laboratory Automation and Middleware.

    Riben, Michael


    The practice of surgical pathology is under constant pressure to deliver the highest quality of service, reduce errors, increase throughput, and decrease turnaround time while at the same time dealing with an aging workforce, increasing financial constraints, and economic uncertainty. Although not able to implement total laboratory automation, great progress continues to be made in workstation automation in all areas of the pathology laboratory. This report highlights the benefits and challenges of pathology automation, reviews middleware and its use to facilitate automation, and reviews the progress so far in the anatomic pathology laboratory. PMID:26065792

  5. Automated cloning methods.; TOPICAL

    Argonne has developed a series of automated protocols to generate bacterial expression clones by using a robotic system designed to be used in procedures associated with molecular biology. The system provides plate storage, temperature control from 4 to 37 C at various locations, and Biomek and Multimek pipetting stations. The automated system consists of a robot that transports sources from the active station on the automation system. Protocols for the automated generation of bacterial expression clones can be grouped into three categories (Figure 1). Fragment generation protocols are initiated on day one of the expression cloning procedure and encompass those protocols involved in generating purified coding region (PCR)

  6. Molecular Weight and Association of Asphaltenes: a Critical Review Masse moléculaire et association des asphaltènes : une revue critique

    Speight J. G.


    Full Text Available The determination of asphaltene molecular weights is complicated by the tendency of asphaltene molecules to associate with each other and with other petroleum constituents, and reported molecular weights vary from 900 to 300 000. This paper reviews the methods (vapor pressure osmometry, size exclusion chromatography, ultrafiltration, ultracentrifugation, viscosity, small angle X-ray scattering, infrared spectroscopy, solubilization, and interfacial tension that have been used to estimate asphaltene molecular weights and to probe association phenomena. It is concluded that asphaltene fractions from typical crudes have a number average molecular weight of 1 200-2 700 and a molecular weight range of 1,000-10,000 or higher. Intermolecular association phenomena are primarily responsible for observed molecular weights up to and in excess of 100,000 but detailed mechanisms of the intermolecular associations are not well understood. Certain observations suggest that asphaltene molecules are associated in reversedmicelles and that asphaltenes interact selectively with resins although the evidence on these points is subject to alternate interpretations. H-bond interactions between asphaltenes and resins have been demonstrated. La détermination de la masse moléculaire des asphaltènes est difficile à cause de la tendance qu'ont les molécules d'asphaltènes à s'associer les unes aux autres et avec d'autres constituants des pétroles. Ces masses moléculaires varient de 900 à 300 000. Cet article passe en revue les méthodes (osmométrie par tension de vapeur, chromatographie d'exclusion stérique, ultrafiltration, ultracentrifugation, viscosité, diffusion centrale des rayons X, spectroscopie infra-rouge, solubilisation et tension interfaciale qui ont été utilisées pour estimer les masses moléculaires des asphaltènes et pour étudier les phénomènes d'association. On conclut que les asphaltènes extraits de bruts types ont des masses mol

  7. Library Automation Style Guide.

    Gaylord Bros., Liverpool, NY.

    This library automation style guide lists specific terms and names often used in the library automation industry. The terms and/or acronyms are listed alphabetically and each is followed by a brief definition. The guide refers to the "Chicago Manual of Style" for general rules, and a notes section is included for the convenience of individual…

  8. Automation in Warehouse Development

    Hamberg, R.; Verriet, J.


    The warehouses of the future will come in a variety of forms, but with a few common ingredients. Firstly, human operational handling of items in warehouses is increasingly being replaced by automated item handling. Extended warehouse automation counteracts the scarcity of human operators and support

  9. Automate functional testing

    Ramesh Kalindri


    Full Text Available Currently, software engineers are increasingly turning to the option of automating functional tests, but not always have successful in this endeavor. Reasons range from low planning until over cost in the process. Some principles that can guide teams in automating these tests are described in this article.

  10. Automation in Immunohematology

    Meenu Bajpai


    Full Text Available There have been rapid technological advances in blood banking in South Asian region over the past decade with an increasing emphasis on quality and safety of blood products. The conventional test tube technique has given way to newer techniques such as column agglutination technique, solid phase red cell adherence assay, and erythrocyte-magnetized technique. These new technologies are adaptable to automation and major manufacturers in this field have come up with semi and fully automated equipments for immunohematology tests in the blood bank. Automation improves the objectivity and reproducibility of tests. It reduces human errors in patient identification and transcription errors. Documentation and traceability of tests, reagents and processes and archiving of results is another major advantage of automation. Shifting from manual methods to automation is a major undertaking for any transfusion service to provide quality patient care with lesser turnaround time for their ever increasing workload. This article discusses the various issues involved in the process.

  11. Automated model building

    Caferra, Ricardo; Peltier, Nicholas


    This is the first book on automated model building, a discipline of automated deduction that is of growing importance Although models and their construction are important per se, automated model building has appeared as a natural enrichment of automated deduction, especially in the attempt to capture the human way of reasoning The book provides an historical overview of the field of automated deduction, and presents the foundations of different existing approaches to model construction, in particular those developed by the authors Finite and infinite model building techniques are presented The main emphasis is on calculi-based methods, and relevant practical results are provided The book is of interest to researchers and graduate students in computer science, computational logic and artificial intelligence It can also be used as a textbook in advanced undergraduate courses

  12. Automation in Warehouse Development

    Verriet, Jacques


    The warehouses of the future will come in a variety of forms, but with a few common ingredients. Firstly, human operational handling of items in warehouses is increasingly being replaced by automated item handling. Extended warehouse automation counteracts the scarcity of human operators and supports the quality of picking processes. Secondly, the development of models to simulate and analyse warehouse designs and their components facilitates the challenging task of developing warehouses that take into account each customer’s individual requirements and logistic processes. Automation in Warehouse Development addresses both types of automation from the innovative perspective of applied science. In particular, it describes the outcomes of the Falcon project, a joint endeavour by a consortium of industrial and academic partners. The results include a model-based approach to automate warehouse control design, analysis models for warehouse design, concepts for robotic item handling and computer vision, and auton...

  13. Advances in inspection automation

    Weber, Walter H.; Mair, H. Douglas; Jansen, Dion; Lombardi, Luciano


    This new session at QNDE reflects the growing interest in inspection automation. Our paper describes a newly developed platform that makes the complex NDE automation possible without the need for software programmers. Inspection tasks that are tedious, error-prone or impossible for humans to perform can now be automated using a form of drag and drop visual scripting. Our work attempts to rectify the problem that NDE is not keeping pace with the rest of factory automation. Outside of NDE, robots routinely and autonomously machine parts, assemble components, weld structures and report progress to corporate databases. By contrast, components arriving in the NDT department typically require manual part handling, calibrations and analysis. The automation examples in this paper cover the development of robotic thickness gauging and the use of adaptive contour following on the NRU reactor inspection at Chalk River.

  14. Improvement of Test Automation

    Räsänen, Timo


    The purpose for this study was to find out how to ensure that the automated testing of MME in the Network Verification will continue smooth and reliable while using the in-house developed test automation framework. The goal of this thesis was to reveal the reasons of the currently challenging situation and to find the key elements to be improved in the MME testing carried by the test automation. Also a reason for the study was to get solutions as to how to change the current procedures and wa...

  15. Chef infrastructure automation cookbook

    Marschall, Matthias


    Chef Infrastructure Automation Cookbook contains practical recipes on everything you will need to automate your infrastructure using Chef. The book is packed with illustrated code examples to automate your server and cloud infrastructure.The book first shows you the simplest way to achieve a certain task. Then it explains every step in detail, so that you can build your knowledge about how things work. Eventually, the book shows you additional things to consider for each approach. That way, you can learn step-by-step and build profound knowledge on how to go about your configuration management

  16. Automation of radiochemical analysis by flow injection techniques. Am-Pu separation using TRU-resinTM sorbent extraction column

    A rapid automated flow injection analysis (FIA) procedure was developed for efficient separation of Am and Pu from each other and from interfering matrix and radionuclide components using a TRU-resinTM column. Selective Pu elution is enabled via on-column reduction. The separation was developed using on-line radioactivity detection. After the separation had been developed, fraction collection was used to obtain the separated fractions. In this manner, a FIA instrument functions as an automated separation workstation capable of unattended operation. (author)

  17. Automated Vehicles Symposium 2014

    Beiker, Sven; Road Vehicle Automation 2


    This paper collection is the second volume of the LNMOB series on Road Vehicle Automation. The book contains a comprehensive review of current technical, socio-economic, and legal perspectives written by experts coming from public authorities, companies and universities in the U.S., Europe and Japan. It originates from the Automated Vehicle Symposium 2014, which was jointly organized by the Association for Unmanned Vehicle Systems International (AUVSI) and the Transportation Research Board (TRB) in Burlingame, CA, in July 2014. The contributions discuss the challenges arising from the integration of highly automated and self-driving vehicles into the transportation system, with a focus on human factors and different deployment scenarios. This book is an indispensable source of information for academic researchers, industrial engineers, and policy makers interested in the topic of road vehicle automation.

  18. I-94 Automation FAQs

    Department of Homeland Security — In order to increase efficiency, reduce operating costs and streamline the admissions process, U.S. Customs and Border Protection has automated Form I-94 at air and...

  19. Automated Vehicles Symposium 2015

    Beiker, Sven


    This edited book comprises papers about the impacts, benefits and challenges of connected and automated cars. It is the third volume of the LNMOB series dealing with Road Vehicle Automation. The book comprises contributions from researchers, industry practitioners and policy makers, covering perspectives from the U.S., Europe and Japan. It is based on the Automated Vehicles Symposium 2015 which was jointly organized by the Association of Unmanned Vehicle Systems International (AUVSI) and the Transportation Research Board (TRB) in Ann Arbor, Michigan, in July 2015. The topical spectrum includes, but is not limited to, public sector activities, human factors, ethical and business aspects, energy and technological perspectives, vehicle systems and transportation infrastructure. This book is an indispensable source of information for academic researchers, industrial engineers and policy makers interested in the topic of road vehicle automation.

  20. Hydrometeorological Automated Data System

    National Oceanic and Atmospheric Administration, Department of Commerce — The Office of Hydrologic Development of the National Weather Service operates HADS, the Hydrometeorological Automated Data System. This data set contains the last...

  1. An automated Certification Authority

    Shamardin, L V


    This note describe an approach to building an automated Certification Authority. It is compatible with basic requirements of RFC2527. It also supports Registration Authorities and Globus Toolkit grid-cert-renew automatic certificate renewal.

  2. Disassembly automation automated systems with cognitive abilities

    Vongbunyong, Supachai


    This book presents a number of aspects to be considered in the development of disassembly automation, including the mechanical system, vision system and intelligent planner. The implementation of cognitive robotics increases the flexibility and degree of autonomy of the disassembly system. Disassembly, as a step in the treatment of end-of-life products, can allow the recovery of embodied value left within disposed products, as well as the appropriate separation of potentially-hazardous components. In the end-of-life treatment industry, disassembly has largely been limited to manual labor, which is expensive in developed countries. Automation is one possible solution for economic feasibility. The target audience primarily comprises researchers and experts in the field, but the book may also be beneficial for graduate students.


    Adan-Yovani León-Bermúdez


    Full Text Available The creation of new polymer compounds to be added to asphalt has drawn considerable attention because these substances have succeeded in modifying the asphalt rheologic characteristics and physical properties for the enhancement of its behavior during the time of use. This work explains the synthesis of a new graft copolymer based on an asphalt fraction called asphaltene, modified with maleic anhydride. Polystyrene functionalization is conducted in a parallel fashion in order to obtain polybenzylamine resin with an amine - NH2 free group, that reacts with the anhydride graft groups in the asphaltene, thus obtaining the new Polystyrene/Asphaltene graft copolymer.La creación de nuevos compuestos poliméricos para ser adicionados al asfalto, ha llamado la atención de manera considerable debido a que estas sustancias han logrado modificar las características reológicas y propiedades físicas del asfalto, con la finalidad de mejorar su comportamiento en el tiempo de uso. El presente trabajo explica, la síntesis de un nuevo copolímero de injerto a partir de una fracción del asfalto llamada asfalteno, la cual es modificada con anhídrido maleico. Paralelamente se realiza la funcionalización del poliestireno, resina polibencilamina, esta posee un grupo amina - NH2 libre que reacciona con los grupos anhídro, injertados en el asfalteno, y así obtener el nuevo copolímero de injerto Poliestireno/Asfalteno.

  4. Automated security management

    Al-Shaer, Ehab; Xie, Geoffrey


    In this contributed volume, leading international researchers explore configuration modeling and checking, vulnerability and risk assessment, configuration analysis, and diagnostics and discovery. The authors equip readers to understand automated security management systems and techniques that increase overall network assurability and usability. These constantly changing networks defend against cyber attacks by integrating hundreds of security devices such as firewalls, IPSec gateways, IDS/IPS, authentication servers, authorization/RBAC servers, and crypto systems. Automated Security Managemen

  5. Automating Supplier Selection Procedures

    Davidrajuh, Reggie


    This dissertation describes a methodology, tools, and implementation techniques of automating supplier selection procedures of a small and medium-sized agile virtual enterprise. Firstly, a modeling approach is devised that can be used to model the supplier selection procedures of an enterprise. This modeling approach divides the supplier selection procedures broadly into three stages, the pre-selection, selection, and post-selection stages. Secondly, a methodology is presented for automating ...

  6. Taiwan Automated Telescope Network

    Shuhrat Ehgamberdiev; Alexander Serebryanskiy; Antonio Jimenez; Li-Han Wang; Ming-Tsung Sun; Javier Fernandez Fernandez; Dean-Yi Chou


    A global network of small automated telescopes, the Taiwan Automated Telescope (TAT) network, dedicated to photometric measurements of stellar pulsations, is under construction. Two telescopes have been installed in Teide Observatory, Tenerife, Spain and Maidanak Observatory, Uzbekistan. The third telescope will be installed at Mauna Loa Observatory, Hawaii, USA. Each system uses a 9-cm Maksutov-type telescope. The effective focal length is 225 cm, corresponding to an f-ratio of 25. The field...

  7. Automated Lattice Perturbation Theory

    Monahan, Christopher


    I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.

  8. Automated functional software testing

    Jelnikar, Kristina


    The following work describes an approach to software test automation of functional testing. In the introductory part we are introducing what testing problems development companies are facing. The second chapter describes some testing methods, what role does testing have in software development, some approaches to software development and the meaning of testing environment. Chapter 3 is all about test automation. After a brief historical presentation, we are demonstrating through s...

  9. Instant Sikuli test automation

    Lau, Ben


    Get to grips with a new technology, understand what it is and what it can do for you, and then get to work with the most important features and tasks. A concise guide written in an easy-to follow style using the Starter guide approach.This book is aimed at automation and testing professionals who want to use Sikuli to automate GUI. Some Python programming experience is assumed.

  10. Colloidal Structure of Heavy Crudes and Asphaltene Soltutions Structure colloïdale des bruts lourds et des suspensions d'asphaltènes

    Barre L.


    Full Text Available Many industrial problems that arise during petroleum processing are related to the high concentration of asphaltenes. A good knowledge of the chemical composition of these macromolecules and a detailed understanding of the evolution of the colloïdal structures present in oil and its derivatives can play a decisive role in improving processing facilities. Asphaltenes are defined by their insolubility in n-heptane. Soluble molecules are called maltenes which can be fractionated by liquid chromatography in so-called resins, aromatic and saturated fractions. The major part of the research carried out on these complex molecules concerned the chemical composition determination from powerful techniques measurements as for instance IR or NMR methods. Nevertheless, very little information on the colloïdal structure of asphaltenes or resins in pure solvent or in real systems is accessible.The molecular weight determination was the first objective; several techniques, as vapour pressure osmometry (VPO, were used. The main conclusion of these determinations was the huge variation of the molecular weight measured by different methods. We used X-ray and neutron small angle scattering techniques in order to deduce the size polydispersity and the weight average molecular weight. Different systems as (i asphaltenes or resins in solution with different solvents, or (ii asphaltene and resin mixtures in suspension with good or bad solvents were investigated as a function of temperature increase. We have exhibited that the aggregation number, i.e. the number of smaller entities , can strongly vary with solvent composition and temperature. Resins appear as very good solvent for asphaltene molecules. Scattering measurements often exhibit strong scattered intensity at small scattering vector, showing the presence in the suspension of large heterogeneities in diluted solutions of asphaltenes and resins. We can suggest that these heterogeneities are due to

  11. Far infrared (terahertz) spectroscopy of a series of polycyclic aromatic hydrocarbons and application to structure interpretation of asphaltenes and related compounds

    Cataldo, Franco; Angelini, Giancarlo; García-Hernández, D. A.; Manchado, Arturo


    A series of 33 different polycyclic aromatic hydrocarbons (PAHs) were studied by far infrared spectroscopy (terahertz spectroscopy) in the spectral range comprised between 600 and 50 cm-1. In addition to common PAHs like naphthalene, anthracene, phenanthrene, fluoranthene, picene, pyrene, benzo[α]pyrene, and perylene, also quite unusual PAHs were studied like tetracene, pentacene, acenaphtene, acenaphtylene, triphenylene, and decacyclene. A series of alkylated naphthalenes and anthracenes were studied as well as methypyrene. Partially or totally hydrogenated PAHs were also object of the present investigation, ranging from tetrahydronaphthalene (tetralin) to decahydronaphthalene (decalin), 9,10-dihydroanthracene, 9,10-dihydrophenanthrene, hexahydropyrene, and dodecahydrotriphenylene. Finally, the large and quite rare PAHs coronene, quaterrylene, hexabenzocoronene, and dicoronylene were studied by far infrared spectroscopy. The resulting reference spectra were used in the interpretation of the chemical structure of asphaltenes (as extracted from a heavy petroleum fraction and from bitumen), the chemical structures of other petroleum fractions known as DAE (distillate aromatic extract) and RAE (residual aromatic extract), and a possible interpretation of components of the chemical structure of anthracite coal. Asphaltenes, heavy petroleum fractions, and coal were proposed as model compounds for the interpretation of the emission spectra of certain proto-planetary nebulae (PPNe) with a good matching in the mid infrared between the band pattern of the PPNe emission spectra and the spectra of these oil fractions or coal. Although this study was finalized in an astrochemical context, it may find application also in the petroleum and coal chemistry.

  12. Automated Camera Calibration

    Chen, Siqi; Cheng, Yang; Willson, Reg


    Automated Camera Calibration (ACAL) is a computer program that automates the generation of calibration data for camera models used in machine vision systems. Machine vision camera models describe the mapping between points in three-dimensional (3D) space in front of the camera and the corresponding points in two-dimensional (2D) space in the camera s image. Calibrating a camera model requires a set of calibration data containing known 3D-to-2D point correspondences for the given camera system. Generating calibration data typically involves taking images of a calibration target where the 3D locations of the target s fiducial marks are known, and then measuring the 2D locations of the fiducial marks in the images. ACAL automates the analysis of calibration target images and greatly speeds the overall calibration process.

  13. Automated telescope scheduling

    Johnston, Mark D.


    With the ever increasing level of automation of astronomical telescopes the benefits and feasibility of automated planning and scheduling are becoming more apparent. Improved efficiency and increased overall telescope utilization are the most obvious goals. Automated scheduling at some level has been done for several satellite observatories, but the requirements on these systems were much less stringent than on modern ground or satellite observatories. The scheduling problem is particularly acute for Hubble Space Telescope: virtually all observations must be planned in excruciating detail weeks to months in advance. Space Telescope Science Institute has recently made significant progress on the scheduling problem by exploiting state-of-the-art artificial intelligence software technology. What is especially interesting is that this effort has already yielded software that is well suited to scheduling groundbased telescopes, including the problem of optimizing the coordinated scheduling of more than one telescope.

  14. Myths in test automation

    Jazmine Francis


    Myths in automation of software testing is an issue of discussion that echoes about the areas of service in validation of software industry. Probably, the first though that appears in knowledgeable reader would be Why this old topic again? What's New to discuss the matter? But, for the first time everyone agrees that undoubtedly automation testing today is not today what it used to be ten or fifteen years ago, because it has evolved in scope and magnitude. What began as a simple linear script...

  15. Automated phantom assay system

    This paper describes an automated phantom assay system developed for assaying phantoms spiked with minute quantities of radionuclides. The system includes a computer-controlled linear-translation table that positions the phantom at exact distances from a spectrometer. A multichannel analyzer (MCA) interfaces with a computer to collect gamma spectral data. Signals transmitted between the controller and MCA synchronize data collection and phantom positioning. Measured data are then stored on disk for subsequent analysis. The automated system allows continuous unattended operation and ensures reproducible results

  16. Automated conflict resolution issues

    Wike, Jeffrey S.


    A discussion is presented of how conflicts for Space Network resources should be resolved in the ATDRSS era. The following topics are presented: a description of how resource conflicts are currently resolved; a description of issues associated with automated conflict resolution; present conflict resolution strategies; and topics for further discussion.

  17. Protokoller til Home Automation

    Kjær, Kristian Ellebæk


    computer, der kan skifte mellem foruddefinerede indstillinger. Nogle gange kan computeren fjernstyres over internettet, så man kan se hjemmets status fra en computer eller måske endda fra en mobiltelefon. Mens nævnte anvendelser er klassiske indenfor home automation, er yderligere funktionalitet dukket op...

  18. Myths in test automation

    Jazmine Francis


    Full Text Available Myths in automation of software testing is an issue of discussion that echoes about the areas of service in validation of software industry. Probably, the first though that appears in knowledgeable reader would be Why this old topic again? What's New to discuss the matter? But, for the first time everyone agrees that undoubtedly automation testing today is not today what it used to be ten or fifteen years ago, because it has evolved in scope and magnitude. What began as a simple linear scripts for web applications today has a complex architecture and a hybrid framework to facilitate the implementation of testing applications developed with various platforms and technologies. Undoubtedly automation has advanced, but so did the myths associated with it. The change in perspective and knowledge of people on automation has altered the terrain. This article reflects the points of views and experience of the author in what has to do with the transformation of the original myths in new versions, and how they are derived; also provides his thoughts on the new generation of myths.

  19. Automated data model evaluation

    Modeling process is essential phase within information systems development and implementation. This paper presents methods and techniques for analysis and evaluation of data model correctness. Recent methodologies and development results regarding automation of the process of model correctness analysis and relations with ontology tools has been presented. Key words: Database modeling, Data model correctness, Evaluation

  20. Automated solvent concentrator

    Griffith, J. S.; Stuart, J. L.


    Designed for automated drug identification system (AUDRI), device increases concentration by 100. Sample is first filtered, removing particulate contaminants and reducing water content of sample. Sample is extracted from filtered residue by specific solvent. Concentrator provides input material to analysis subsystem.


    Dolgorukov, S. O.; National Aviation University; Roman, B. V.; National Aviation University


    The article reflects current situation in education regarding mechatronics learning difficulties. Com-plex of laboratory test benches on electropneumatic automation are considered as a tool in advancing through technical science. Course of laboratory works developed to meet the requirement of efficient and reliable way of practical skills acquisition is regarded the simplest way for students to learn the ba-sics of mechatronics.

  2. Automating spectral measurements

    Goldstein, Fred T.


    This paper discusses the architecture of software utilized in spectroscopic measurements. As optical coatings become more sophisticated, there is mounting need to automate data acquisition (DAQ) from spectrophotometers. Such need is exacerbated when 100% inspection is required, ancillary devices are utilized, cost reduction is crucial, or security is vital. While instrument manufacturers normally provide point-and-click DAQ software, an application programming interface (API) may be missing. In such cases automation is impossible or expensive. An API is typically provided in libraries (*.dll, *.ocx) which may be embedded in user-developed applications. Users can thereby implement DAQ automation in several Windows languages. Another possibility, developed by FTG as an alternative to instrument manufacturers' software, is the ActiveX application (*.exe). ActiveX, a component of many Windows applications, provides means for programming and interoperability. This architecture permits a point-and-click program to act as automation client and server. Excel, for example, can control and be controlled by DAQ applications. Most importantly, ActiveX permits ancillary devices such as barcode readers and XY-stages to be easily and economically integrated into scanning procedures. Since an ActiveX application has its own user-interface, it can be independently tested. The ActiveX application then runs (visibly or invisibly) under DAQ software control. Automation capabilities are accessed via a built-in spectro-BASIC language with industry-standard (VBA-compatible) syntax. Supplementing ActiveX, spectro-BASIC also includes auxiliary serial port commands for interfacing programmable logic controllers (PLC). A typical application is automatic filter handling.

  3. Automated Preferences Elicitation

    Kárný, Miroslav; Guy, Tatiana Valentine

    Prague : Institute of Information Theory and Automation, 2011, s. 20-25. ISBN 978-80-903834-6-3. [The 2nd International Workshop od Decision Making with Multiple Imperfect Decision Makers. Held in Conjunction with the 25th Annual Conference on Neural Information Processing Systems (NIPS 2011). Sierra Nevada (ES), 16.12.2011-16.12.2011] R&D Projects: GA MŠk 1M0572; GA ČR GA102/08/0567 Institutional research plan: CEZ:AV0Z10750506 Keywords : elicitation * decision making * Bayesian decision making * fully probabilistic design Subject RIV: BB - Applied Statistics, Operational Research preferences elicitation.pdf

  4. Automated drawing generation system

    Since automated CAD drawing generation systems still require human intervention, improvements were focussed on an interactive processing section (data input and correcting operation) which necessitates a vast amount of work. As a result, human intervention was eliminated, the original objective of a computerized system. This is the first step taken towards complete automation. The effects of development and commercialization of the system are as described below. (1) The interactive processing time required for generating drawings was improved. It was determined that introduction of the CAD system has reduced the time required for generating drawings. (2) The difference in skills between workers preparing drawings has been eliminated and the quality of drawings has been made uniform. (3) The extent of knowledge and experience demanded of workers has been reduced. (author)

  5. Terminal automation system maintenance

    Coffelt, D.; Hewitt, J. [Engineered Systems Inc., Tempe, AZ (United States)


    Nothing has improved petroleum product loading in recent years more than terminal automation systems. The presence of terminal automation systems (TAS) at loading racks has increased operational efficiency and safety and enhanced their accounting and management capabilities. However, like all finite systems, they occasionally malfunction or fail. Proper servicing and maintenance can minimize this. And in the unlikely event a TAS breakdown does occur, prompt and effective troubleshooting can reduce its impact on terminal productivity. To accommodate around-the-clock loading at racks, increasingly unattended by terminal personnel, TAS maintenance, servicing and troubleshooting has become increasingly demanding. It has also become increasingly important. After 15 years of trial and error at petroleum and petrochemical storage and transfer terminals, a number of successful troubleshooting programs have been developed. These include 24-hour {open_quotes}help hotlines,{close_quotes} internal (terminal company) and external (supplier) support staff, and {open_quotes}layered{close_quotes} support. These programs are described.

  6. ATLAS Distributed Computing Automation

    Schovancova, J; The ATLAS collaboration; Borrego, C; Campana, S; Di Girolamo, A; Elmsheuser, J; Hejbal, J; Kouba, T; Legger, F; Magradze, E; Medrano Llamas, R; Negri, G; Rinaldi, L; Sciacca, G; Serfon, C; Van Der Ster, D C


    The ATLAS Experiment benefits from computing resources distributed worldwide at more than 100 WLCG sites. The ATLAS Grid sites provide over 100k CPU job slots, over 100 PB of storage space on disk or tape. Monitoring of status of such a complex infrastructure is essential. The ATLAS Grid infrastructure is monitored 24/7 by two teams of shifters distributed world-wide, by the ATLAS Distributed Computing experts, and by site administrators. In this paper we summarize automation efforts performed within the ATLAS Distributed Computing team in order to reduce manpower costs and improve the reliability of the system. Different aspects of the automation process are described: from the ATLAS Grid site topology provided by the ATLAS Grid Information System, via automatic site testing by the HammerCloud, to automatic exclusion from production or analysis activities.

  7. Rapid automated nuclear chemistry

    Rapid Automated Nuclear Chemistry (RANC) can be thought of as the Z-separation of Neutron-rich Isotopes by Automated Methods. The range of RANC studies of fission and its products is large. In a sense, the studies can be categorized into various energy ranges from the highest where the fission process and particle emission are considered, to low energies where nuclear dynamics are being explored. This paper presents a table which gives examples of current research using RANC on fission and fission products. The remainder of this text is divided into three parts. The first contains a discussion of the chemical methods available for the fission product elements, the second describes the major techniques, and in the last section, examples of recent results are discussed as illustrations of the use of RANC

  8. Rapid automated nuclear chemistry

    Meyer, R.A.


    Rapid Automated Nuclear Chemistry (RANC) can be thought of as the Z-separation of Neutron-rich Isotopes by Automated Methods. The range of RANC studies of fission and its products is large. In a sense, the studies can be categorized into various energy ranges from the highest where the fission process and particle emission are considered, to low energies where nuclear dynamics are being explored. This paper presents a table which gives examples of current research using RANC on fission and fission products. The remainder of this text is divided into three parts. The first contains a discussion of the chemical methods available for the fission product elements, the second describes the major techniques, and in the last section, examples of recent results are discussed as illustrations of the use of RANC.

  9. Automated Microbial Metabolism Laboratory


    Development of the automated microbial metabolism laboratory (AMML) concept is reported. The focus of effort of AMML was on the advanced labeled release experiment. Labeled substrates, inhibitors, and temperatures were investigated to establish a comparative biochemical profile. Profiles at three time intervals on soil and pure cultures of bacteria isolated from soil were prepared to establish a complete library. The development of a strategy for the return of a soil sample from Mars is also reported.

  10. Components for automated microscopy

    Determann, H.; Hartmann, H.; Schade, K. H.; Stankewitz, H. W.


    A number of devices, aiming at automated analysis of microscopic objects as regards their morphometrical parameters or their photometrical values, were developed. These comprise: (1) a device for automatic focusing tuned on maximum contrast; (2) a feedback system for automatic optimization of microscope illumination; and (3) microscope lenses with adjustable pupil distances for usage in the two previous devices. An extensive test program on histological and zytological applications proves the wide application possibilities of the autofocusing device.