Asphaltene Components Research Articles

Development and performance evaluation of composite flame retardant based on the thermodynamic properties of asphalt components

The demand for enhanced flame retardancy in asphalt pavement has increased due to its extensive use in enclosed spaces like tunnels. Based on four components of asphalt, the thermodynamic tests, basic performance tests, limit oxygen index tests, storage stability tests, and microscopic experiments were used to prepare and evaluate a new type of composite flame retardant asphalt. The results indicated that the thermal stability of the saturate and aromatic fractions was poor, while the resin and asphaltene components exhibited better thermal stability during combustion. The thermodynamic properties of the selected flame retardant materials were matched with different asphalt components. Three flame retardant systems were designed, and the final composition ratio was determined using orthogonal experiments and the entropy method. Compared to single and binary flame retardant systems, the asphalt with the three-component flame retardant system showed significantly better flame retardant performance. The softening point difference of asphalt increased continuously with higher flame retardant dosages. To maintain storage stability, the flame retardant content should be controlled below 12 %. Despite some agglomeration, most flame retardants were present as individual particles, indicating good dispersion in the asphalt. This study delves into the multi-stage combustion dynamics of asphalt from the perspective of its components and proposes a composite flame retardant formulation scheme. The findings are significant for the development of tunnel asphalt pavement and environmental protection.

Evaluation of compatibility in bio-oil and zinc oxide modified asphalt to facilitate waste recycling

The promotion of bio-oil (Bo) waste in road asphalt modification has significant potential for application and environmental benefits. The thermal storage stability, rheological properties, and nano-microstructural characteristics of the composite modified asphalt system were investigated. The Cole-Cole diagram effectively evaluated the compatibility of modified asphalt, demonstrating high sensitivity and accuracy. Significant interaction energy was observed between zinc oxide (ZnO) and asphaltene, with asphaltene primarily acting as an electron donor during its interaction with ZnO. The three organic small molecules in Bo primarily interacted with the polar molecules in asphalt through ester groups, exhibiting varied interaction effects with asphaltene. Bo influenced the colloidal structure of asphalt mainly through diffusion and molecular intercalation. When Bo constituted 4% of the composite modified asphalt system, the organic small molecules from Bo fully diffused within the asphalt matrix, inhibiting the stacking of aromatic rings in the asphaltene structure and enhancing the aromatic activity of asphaltene. Bo improved the compatibility between ZnO and asphalt primarily through dilution and balancing effects from the perspective of asphaltene components. The research results can promote the promotion and application of bio-oil waste in asphalt pavement engineering, which is an important measure to practice sustainable development.

Effect of Nanostructured Shungite on the Rheological Properties of Bitumen

Improving the physico-mechanical characteristics of bitumen is a constant and pressing problem in road construction. The issue is solved by modifying bitumen with various additives, one of which is a nanostructured modifier. This paper examines the effect of adding a natural mineral, shungite, to bitumen from the Koksu deposit (Kazakhstan) after grinding under different conditions. The mechanochemical activation of shungite made it possible to obtain samples with an average particle diameter of up to 3 μm. Using scanning electron microscopy, nanostructured particles with sizes of up to 100 nm were discovered in their structure. The effect of nanostructured shungite on the rheological characteristics of bitumen—elasticity and loss moduli, and loss tangent at high and low temperatures—was studied. The transition temperatures of bitumen from the viscoelastic to the liquid state were established, and their shift to the region of elevated temperatures when modified with ground shungite are shown. The presence of organic and inorganic components in the composition of shungite—carbon, silica, and metal oxides—has a beneficial effect on the rheological properties of bitumen by forming bonds with resinous asphaltene components of bitumen. The use of bitumen modified with nanostructured shungite makes it possible to replace the polymer modifier with a natural mineral to improve the quality of the road surface.

Biodegradation of Crude Oil by Nitrate-Reducing, Sulfate-Reducing, and Methanogenic Microbial Communities under High-Pressure Conditions.

Carbon capture, utilization, and storage (CCUS) is an important component in many national net-zero strategies, and ensuring that CO2 can be safely and economically stored in geological systems is critical. Recent discoveries have shown that microbial processes (e.g., methanogenesis) can modify fluid composition and fluid dynamics within the storage reservoir. Oil reservoirs are under high pressure, but the influence of pressure on the petroleum microbial community has been previously overlooked. To better understand microbial community dynamics in deep oil reservoirs, we designed an experiment to examine the effect of high pressure (12 megapascals [MPa], 60 °C) on nitrate-reducing, sulfate-reducing, and methanogenic enrichment cultures. Cultures were exposed to these conditions for 90 d and compared with a control exposed to atmospheric pressure (0.1 MPa, 60 °C). The degradation characteristic oil compounds were confirmed by thin-layer analysis of oil SARA (saturates, aromatics, resins, and asphaltenes) family component rods. We found that the asphaltene component in crude oil was biodegraded under high pressure, but the concentration of asphaltenes increased under atmospheric pressure. Gas chromatography analyses of saturates showed that short-chain saturates (C8-C12) were biodegraded under high and atmospheric pressure, especially in the methanogenic enrichment culture under high pressure (the ratio of change was -81%), resulting in an increased relative abundance of medium- and long-chain saturates. In the nitrate-reducing and sulfate-reducing enrichment cultures, long-chain saturates (C22-C32) were biodegraded in cultures exposed to high-pressure and anaerobic conditions, with a ratio of change of -8.0% and -2.3%, respectively. However, the relative proportion of long-chain saturates (C22-C32) increased under atmospheric pressure. Gas Chromatography Mass Spectrometry analyses of aromatics showed that several naphthalene series compounds (naphthalene, C1-naphthalene, and C2-naphthalene) were biodegraded in the sulfate-reducing enrichment under both atmospheric pressure and high pressure. Our study has discerned the linkages between the biodegradation characteristics of crude oil and pressures, which is important for the future application of bioenergy with CCUS (bio-CCUS).

Effect of waste cooking oil on the performance of EVA modified asphalt and its mechanism analysis

The balance between the low and high temperature performance of asphalt materials is important to avoid either rutting deformation or low temperature cracking resistance of asphalt pavement. This is beneficial for improving the asphalt pavement comprehensive performance. Considering the excellent high temperature performance of Ethylene–vinyl acetate (EVA) modified asphalt, this study first modified it with Waste Biological Oil (WBO) to prepare WBO/EVA composite modified asphalt (WEMA) with different dosages. Then the samples were evaluated by the traditional physical properties, low and high temperature rheological properties. Finally, the micro mechanism of WBO on EVA modified asphalt were explored by gel permeation chromatography (GPC) test and atomic force microscope (AFM) experiments. The experimental results reveal that WBO has a softening effect on EVA modified asphalt, reducing its stiffness and improving its stretching performance and flowability. In addition, WBO can reduce the high-temperature deformation resistance of EMA modified asphalt, but it significantly enhances the low-temperature property of EVA modified asphalt. When the WBO content ranges from 1.5 to 2.5%, the high-temperature performance of WEMA is inferior to that of EVA-modified asphalt, however, its low-temperature performance is significantly better than that of EVA-modified asphalt. Importantly, within this WBO content range, the comprehensive performance of WEMA is superior to that of pure asphalt. Mechanism investigation showed that WBO reduces the content of macromolecular micelles and average molecular weight in EVA modified asphalt, and it also diluts the asphaltene components in the asphalt system, resulting in a slight weakening of the performance of WEMA at high temperatures and a significant performance enhancement at low temperatures. Ultimately, the utilization of WBO/EVA composite modified asphalt has a better comprehensive performance.

Examining the rheological and adhesion performance of asphalt: Insights into the influence of SARA components

The role of chemical components is pivotal in determining the rheological and adhesion performance of asphalt binders. In this study, the saturate, aromatic, resin, and asphaltene (SARA) components were directly blended with the original asphalt in specific proportions, enabling a direct assessment of their influence on critical asphalt properties. Various tests, including frequency sweep, temperature sweep, and multiple stress creep and recovery tests, were conducted, followed by the utilization of master curves to analyze the rheological properties of SARA-doped asphalt. Additionally, binder bond strength tests were performed to evaluate the adhesion properties of SARA-doped asphalt binders. The research outcomes revealed that the complex modulus, rutting factor, creep and recovery behaviors increased with higher asphaltene and resin proportions, while diminishing with elevated saturate and aromatic proportions. Analysis of the Glover–Rowe (G-R) parameter variation indicated that increasing the proportion of aromatic and saturate components can enhance cracking resistance, with the aromatic component playing a particularly significant role in this enhancement. Furthermore, augmenting the proportion of heavy components was found to enhance the adhesion performance between asphalt and commonly used aggregates. Notably, the pattern of interfacial failure transitioned from cohesive failure to adhesive failure gradually with rising proportions of heavy components.

From Bin to Binder: Unleashing Waste Butter’s Potential as a Pioneering Bio-Modifier for Sustainable Asphalt Engineering

Exploring the interface of environmental sustainability and civil infrastructure development, this study introduces waste butter (WB), a byproduct of animal fat processing, as a novel bio-modifier in asphalt production. This approach not only recycles animal waste but also charts a course for sustainable infrastructural development, contributing to a reduced environmental impact and promoting circular economy practices. The experiments incorporated varying WB concentrations (e.g., 3%, 6%, and 9% by weight of binder) into standard AP-5 asphalt, employing advanced analytical tools for comprehensive characterization. These included thin-layer chromatography–flame ionization detection (TLC-FID), Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), and Differential Scanning Calorimetry (DSC). The critical properties of the asphalt blends, such as penetration, softening point, viscosity, ductility, rutting factor (Dynamic Shear Rheometer), and thermal susceptibility (Penetration Index, Penetration–Viscosity Number), were assessed. FT-IR analysis indicated negligible chemical alteration with WB addition, suggesting predominantly physical interactions. TLC-FID showed a decrease in aromatic and asphaltene components but an increase in resin content, highlighting the influence of WB’s fatty acids on the asphalt’s chemical balance. The colloidal instability index (IC) confirmed enhanced stability due to WB’s high resin concentration. Meanwhile, SEM analysis revealed microstructural improvements with WB, enhancing binder compatibility. TGA demonstrated that even a minimal 3 wt. % WB addition significantly improved thermal stability, while the DSC results pointed to improved low-temperature performance, reducing brittleness in cold conditions. Rheologically, WB incorporation resulted in increased penetration and ductility, balanced by decreased viscosity and softening point, thereby demonstrating its multi-faceted utility. Thermal susceptibility tests emphasized WB’s effectiveness in cold environments, with further evaluation needed at higher temperatures. The DSR findings necessitate careful WB calibration to meet Superpave rutting standards. In conclusion, this research positions waste butter as a superior, environmentally aligned bio-additive for asphalt blends, contributing significantly to eco-friendly civil engineering practices by repurposing animal-derived waste.

Formation behaviors of gas hydrates in water-in-oil emulsions with the coexistence of asphaltenes and resins

Hydrate formation is one of the major flow assurance issues for the subsea multiphase pipelines. The effects of the interaction between heavy fractions of crude oil components on hydrate behaviors are still not well understood. In this study, the effects of resins on hydrate formation behaviors in asphaltene-containing emulsions were investigated using a high-pressure reactor apparatus. The results indicated that both resins and asphaltenes inhibited hydrate nucleation and increased the induction time. Furthermore, considerable synergistic effects of asphaltenes and resins on the hydrate formation behaviors were discovered in the water-in-oil emulsions, depending on the aggregation state of asphaltenes. The addition of resins was observed to disperse the asphaltene aggregates significantly and enhance the inhibitory effect of asphaltenes on hydrate nucleation. Additionally, the calculated results of gas consumption showed that the presence of resins can decrease the growth rate of hydrates in the asphaltene-containing emulsions. A potential mechanism was presented to illustrate how resins affect hydrate formation in an emulsion with varying asphaltene aggregation states. These findings offer a better knowledge of the synergistic effects between the heavy components of resins and asphaltenes and have potential application in the hydrate management of crude oil pipelines.

Insights into the effect of water content on asphaltene aggregation behavior and crude oil rheology: A molecular dynamics simulation study

In the production and transportation of crude oils, the interaction between asphaltene components and water is inevitable, significantly impacting asphaltene aggregation, deposition behaviors, emulsion stability, and rheological properties of crude oils. However, the comprehension of the oil-water interaction mechanisms and corresponding viscosity responses remains unclear. Hence, we performed molecular dynamics (MD) simulations to investigate the effect of varying water content on distinct asphaltene aggregation states and the rheological behavior of crude oils. The microscopic mechanisms underlying the aggregation and rheological properties were elucidated. Our MD results show that with the continuous introduction of water, the original bulk phase aggregation of asphaltenes undergoes a transition towards interfacial adsorption behavior, culminating in the formation of water-in-crude oil emulsions. The strength and driving forces of this interfacial adsorption are influenced by different polar functional groups of asphaltene. Besides, by elucidating the contributions of external molecular friction and internal structural deformation to the viscosity, two viscosity-influencing mechanisms are revealed. Furthermore, we delineate a physical viscosity scheme. These intriguing discoveries hold promise for advancing the comprehension of rheological behavior in crude oils with distinct aggregation states, providing theoretical guidance for efficient development of crude oils.

Composition transformation of terrigenous organic matter resinous-asphaltene components in super-deep wells in Siberia during meso- and apocatagenesis

The evolution of the elemental composition of dispersed organic matter (DOM) heterocyclic components during catagenesis was traced via studying samples from the Tyumen (SG-6) and Srednevylyuy-27 (SV-27) super-deep wells of Siberia. During mesocatagenesis, the composition of terrigenous DOM asphaltenes and resins undergoes directed changes: a decrease in hydrogen and oxygen content, enrichment with carbon, and graphitization of the structure. During apocatagenesis, due to high-temperature destruction, on the one hand, there is a condensation of individual blocks of asphaltenes and their transition to an insoluble form (formation of epiasphaltenic kerogens – EPAK). On the other hand, the lighter part of the asphaltenes goes into the formation of hydrocarbons and gas formation – a relative increase in the concentration of the former in % by mass of residual bitumoids is noted, as well as structural redistributions within benzene and spirit-benzene resins. In all studied parameters of the elemental composition, a symmetrical (unidirectional) transformation of resinous and asphaltene components of bitumoids from the SG-6 and SV-27 wells under harsh thermobaric conditions is noted. The obtained results should be taken into account when predicting new oil and gas accumulation zones in deep-laid horizons.

Occurrence of deep liquid oil reservoirs in the Sichuan and Tarim basins as constrained by geological evidences and molecular simulation

The hydrocarbon phase state of deep to ultra-deep reservoirs in the Tarim and Sichuan basins has been of great interest in oil and gas exploration. Based on a combination of molecular dynamics simulation, gold-tube pyrolysis experiments, and geological-geochemical theory, this study discusses the mechanisms governing the stability of oils in deep reservoirs from the perspectives of their reservoir accumulation histories and chemical reactions. Generally, the reason for the existence of liquid oil in the Tarim Basin is widely considered to be only controlled by external geological conditions, mainly including low geothermal gradient, absence of thermal events, low maximum reservoir temperatures, and late hydrocarbon generation process. However, this study firstly proposed that the chemical composition of oil is an internal factor for its thermal stability. The simulation results reveal that the polycondensation reactions of asphaltene will release hydrogen atoms, which can provide a necessary hydrogen source for cracking of liquid chain hydrocarbons. It means that the presence of asphaltene components can promote the cracking of chain hydrocarbons and generate methane. The normal mature oil in the Sichuan Basin generally has higher contents of asphaltenes than that of the high-mature light oil of the Tarim Basin, so more hydrogen has historically been available for the cracking of oil to gas. By looking at the accumulation histories and chemical compositions of the crude oils, this study first explains the stable long-term storage of liquid hydrocarbons in the Tarim Basin, providing important guidance for future deep to ultra-deep oil and gas exploration.

An atomistic model of aged asphalt guided by the oxidation chemistry of benzylic carbon with application to asphalt rejuvenated with a triglyceride

Waste cooking oil (WCO) shows promise for restoring physical properties of aged asphalt binder to enable pavement recycling. Its use as a rejuvenator lessens the environmental burden on land fills with its disposal. In this study, we report our initial development of an aged asphalt model and the computational investigation of the effect of triglycerides, the main component of WCO, on the viscosity, self-diffusion, and microstructural properties of aged asphalt at 1 atm and 404 K. The fundamental research question in this work involves understanding the underlying mechanism(s) by which WCO rejuvenates aged asphalt binder. A central feature of this aged asphalt model is consideration of oxidation chemistry and reported functional group concentrations since properties like viscosity are known to be related to the amounts of moieties such as ketones and sulfoxides. Model oxidation compounds include proposed representative asphalt structures based on Peterson’s dual reaction pathways, leading to polycyclic aromatic hydrocarbon molecules resulting from fast phase aromatization and multiple species from a slow phase degradation of benzylic hydroperoxide intermediates. The new model takes into account the observed product distribution of aryl alcohols and aryl ketones based on findings for cumene oxidation in the literature. Other oxygen-containing functional groups, such as anhydrides, carboxylic acids, and polynuclear aromatics, have been incorporated to account for the critical physical characteristics of aged asphalt. By extending the molecular basis set of asphalt components, we can now construct more realistic asphalt models to represent varying SARA (Saturates, Aromatics, Resins, Asphaltents) content, different oxidation levels and functional group composition. Virtual representations of the molecules in the basis set were created and molecular dynamics simulations of the aged asphalt model conducted. Results with aged asphalt basis set provided good agreement with reported physical properties. With the developed aged asphalt model, our molecular dynamics simulations reveal that triglyceride (tristearin) has preferential interactions with asphaltene molecules. On addition of 10 wt% triglyceride to aged asphalt, the asphaltene-asphaltene interaction was most significantly affected. The radial distribution functional analysis revealed that the asphaltene-asphaltene nearest neighbor distance increased from 4.0 Å to 7.5 Å. Thus, adding triglyceride to aged asphalt helps to reduce the aggregation of asphalt components and as such promotes a decrease in viscosity of the aged asphalt, from 83 cP to 69 cP. In addition, the asphaltene components have larger self-diffusion coefficients upon the addition of triglyceride, changing from 3.57 × 10−8 cm2/s in the aged asphalt to 1.41 × 10−7 cm2/s in the triglyceride/aged asphalt mixture. Those findings are consistent with the observed effectiveness of utilizing waste cooking oil to rejuvenate aged asphalt.

The influence of composition of asphaltenes of different genesis on the properties of carbon materials manufactured from them by plasma processing

The results of experimental studies of carbon materials, which are formed in the plasma of a direct current (DC) arc discharge initiated in open air from the asphaltenes of different origins, extracted from the natural asphaltite and from the oil of the Sredne-Ugutskoye Oilfield, are presented. The influence of the initial asphaltene composition on the composition and properties of the resulting carbon materials is analyzed. The initial asphaltenes and the samples of the carbon materials are characterized by the methods of X-ray diffraction, differential thermal analysis, X-ray fluorescence analysis, IR-Fourier spectroscopy, laser diffraction, transmission and scanning electron microscopy. The changes in the composition and structure of the asphaltenes are determined before and after their plasma treatment and the hypotheses are put forward concerning the chemical processes causing the changes in the molecular structure of the samples. As a result of plasma treatment of asphaltenes (100 A, 30 s), it was shown that graphitization occurs, as well as oxidation, and a decrease in sulfur content. Moreover, nanotubes and nano-onions have been detected using electron microscopy. Petroleum asphaltenes after plasma treatment give a less thermostable carbon material, but with a lower content of heteroatoms, and with a large amount of sulfur in the composition of sulfoxide structural fragments. This method is shown to be a promising technology for processing the petroleum feedstock enriched with heavy asphaltene components for the manufacture of carbon nanomaterials: nanotubes, nano-onions and polyhedral graphite.

Microscopic Analysis of Aging Effects on the Adhesion Properties between Asphalt and Mineral Aggregate

This research investigated the effect of aging on the adhesion properties between asphalt and aggregate at the molecular level. Based on the molecular dynamics simulation method, the adhesion characteristics of asphalt component representative molecules and bulk asphalt with silica mineral aggregate before and after aging were evaluated in terms of adsorption energy and adhesion work, respectively. In addition, the simulation results were verified using a pull-off test. Results show that the adsorption energy increases after aging, and was most pronounced for the representative molecules of the asphaltene component. In bulk asphalt, the increase of large-mass molecules after aging led to an increase in its adhesion to mineral aggregate. The presence of water greatly weakened the adhesion strength between asphalt and mineral aggregate, and the negative effect of water on the adhesion strength between aged asphalt and mineral aggregate was severer. The pull-off test confirmed that aging enhanced the adhesion strength between asphalt and aggregate, but exacerbated the negative impact of water on the adhesion strength between asphalt and aggregate. The findings promote further understanding of the effect of aging on the adhesion properties of asphalt to mineral aggregate and the water damage mechanism of asphalt mixtures.

The effect of low-temperature oxidation on asphaltene structure and properties during air injection

Air injection is a promising method to enhance light crude oil recovery. To effectively utilize this technology, understanding the oxidation behaviour and interactions of SARA components during low-temperature oxidation (LTO) is crucial. In this study, the SARA components of two light crude oils from the Xinjiang oilfield were characterized during LTO under air and nitrogen atmospheres, respectively. Firstly, our results revealed that the oxidation behaviour under air significantly affected crude oil stability at temperatures above 150 °C. Secondly, asphaltene component exhibited the highest oxidative activity, leading to the introduction of more oxygen and further oxidation of C–O groups and sulphoxides on the asphaltene surface. This resulted in stronger intermolecular forces among asphaltene molecules. Furthermore, the polarity characterization showed increased polarity difference between asphaltenes and resins. Structural parameters changes were observed in asphaltene aggregates, with enhanced aromaticity and accumulation of aromatic sheets after LTO reactions. Finally, these findings contribute to a deeper understanding of SARA component oxidation and interactions during LTO process, which is valuable for future air injection applications.

Structural Organization of Asphaltenes and Resins and Composition of Low Polar Components of Heavy Oils

Comparative characteristics of resins, asphaltenes, and low polar components of heavy oils from the Ashalchinskoye (I) and Nurlatskoye (II) oil fields (Republic of Tatarstan, Russia) are given. These oils differ in the age of host rocks (Permian and Devonian, respectively) and the content of their components and heteroatoms. An X-ray phase analysis and scanning and transmission electron microscopy reveal that, in contrast to smooth surface asphaltenes of oil I, asphaltenes of oil II are characterized by a loose and porous surface and smaller sizes of nanoaggregates. Nanoaggregates form a disorderly tangled structure because of the alkyl side-chain configuration, which makes it difficult to stack aromatic sheets. The crystallites of nanoaggregates of asphaltenes of oil II are smaller than the crystallites of nanoaggregates of asphaltenes of oil I. The application of the method of structural-group analysis based on the use of the measured indicators of the elemental composition, average molecular weights, and the results of 1H NMR spectroscopy made it possible to establish that overall sizes of mean molecules of resins and asphaltenes of heavy oil I are larger due to the increased content of aromatic and naphthenic cycles in the naphthenoaromatic system. A feature of the structure of the resin–asphaltene components of oil II is a greater number of alkyl substituents in the side chains. According to gas chromatography–mass spectrometry (GC–MS) analysis, the low polar components under study are characterized by a similar set of saturated hydrocarbons (n-alkanes, mono-, and polycycloalkanes) but differ in the composition of identified aromatic hydrocarbons and heteroorganic compounds. A feature of the low polar components of oil II is the presence of a wider range of n-alkyl- and phenylalkyl-substituted benzenes and nitrogen- and oxygen-organic compounds in their composition.

Interfacial Performance of Asphalt-Aggregate System under Different Conditions Based on Molecular Dynamics Simulation

The interface between asphalt and aggregate directly determines the performance of asphalt mixtures but unavoidable weaknesses can be easily found at the interfacial bonding region. In order to evaluate the interfacial adhesion behavior between asphalt and aggregate at the atomic scale, asphalt binders and two mineral aggregates (quartz and calcite) were selected to build molecular models and molecular dynamics (MD) simulations were conducted. The interfacial energy between asphalt and aggregate was calculated and the mineral aggregate has a more significant influence on the energy compared to the binder types. Also, the simulation result indicates that saturate, aromatic, resin, and asphaltene (SARA) components have different interfacial energies with respect to the aggregates. This result can also be derived from the relative concentration of SARA components on the aggregate surface. Additionally, oxidation of the asphalt binder results in increased interfacial energy due to the enhanced intermolecular bonding generated by oxidized functional groups. The intrusion of water greatly reduces the interfacial energy, but the energy increases under the coupling effect of oxidation and moisture, especially for calcite. The grey relational grade theory was conducted to evaluate the factors affecting the adhesive energy, and the results show that the energy of the asphalt-aggregate is more sensitive to the asphaltene index than other factors.

Plasma Processing of Light- and Heavy-Oil Asphaltenes

The paper presents an analysis of the results of an experimental study of carbon materials obtained in a direct-current arc plasma from asphaltenes isolated from light oil of the Sredneugutskoye field and combined heavy oil from Venezuelan fields, as well as asphaltenes isolated from natural asphaltite. The influence of the composition of initial asphaltenes on the composition and properties of carbon materials obtained as a result of plasma treatment has been studied. The parent asphaltenes and carbon materials synthesized from them have been examined using a set of instrumental methods: X-ray diffraction, thermogravimetric analysis, energy-dispersive X-ray fluorescence analysis, Fourier-transform IR spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission and scanning electron microscopy, and laser diffraction. Changes in the composition and structure of the obtained materials after plasma processing of asphaltenes have been established. It is shown that this method can be considered promising for processing not only petroleum material, but also oil industry waste enriched in resin–asphaltene components.

THE USE OF BENZENE OXIDATION PRODUCT AS A COMPONENT OF AN INHIBITORY ADDITIVE FOR PARAFFINIC AND HIGHLY PARAFFINIC PETROLEUM

Results of the application of benzene oxidation product (BOP), formed in barrier discharge, as an improving component of the inhibiting additive for paraffinic and highly paraffinic petroleum are presented. The proposed additive consists of a copolymer of alkyl acrylates with dodecylamine acrylate and BOP at a ratio of 15:1 wt. %. Benzene oxidation by air in a barrier discharge proceeds predominantly to phenol (~77.3 wt. %), diatomic phenols, and an insignificant amount of macromolecular compounds. The effect of the additive (in combination with BOP) in the amount of 0.03-0.05 wt. was evaluated relying on changes in the rheological characteristics and freezing point of paraffinic and highly paraffinic petroleum with a high content of resins and asphaltene components. The composition containing polymer and BOP additionally reduces the amount of asphaltene-resin-paraffin deposits by 1.5-2.5 g, which gives an increase in inhibitory capacity by 10-12 %. The depression of the freezing point of petroleum is 46 °С on average. The dynamic viscosity of petroleum under study decreases in the presence of the additive by a factor of 2.2 on average.

Quantitative determination of petroleum hydrocarbons in oily sludge following efficient n-heptane separation

Accurate analysis of the main chemical components of oil-bearing sludge is an important prerequisite for effective soil remediation and resource reuse. However, precise analysis of the extract components is difficult to achieve because of the mutual interference of saturates, aromatics, and resins, collectively called SAR, and asphaltene that are introduced during chloroform extraction. In this study, SAR was efficiently extracted using n-heptane, while asphaltene components were retained in soil because of their insolubility in n-heptane. The maximum yield of SAR extraction was 27.0%, indicating an increase of 1.75% compared to chloroform extraction. The extracted SAR components were separated by chromatography and the main structural units and components were analyzed. The results show that saturates, aromatics, and resins have a single component, a high content of major components, and contain fewer impurities using n-heptane extraction. Moreover, the solubility of asphaltene was inhibited during the effective extraction of SAR components with n-heptane and did not influence the subsequent analysis of SAR component. Efficient SAR extraction, accurate SAR component analysis, and high efficiency asphaltene separation was achieved using n-heptane-extraction-assisted pyrolysis. This provides a new method for the component analysis of oily sludge and promotes its efficient separation.