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•Microwave radiation was successfully applied for crude oil demulsification.•Multimode microwave radiation provided faster heating.•Single mode microwave radiation spent less ...energy.•Total applied energy rules the demulsification efficiency.
During petroleum production and refining, water-in-crude oil emulsions are formed in a desirable or undesirable fashion. However, for economic and operational reasons it is necessary to separate water from oil. In order to present an alternative to the currently available techniques used to solve such task, this study aims to analyze the influence of microwave application modes (multimode and single mode) on the breaking efficiency of a synthetic water-in-crude oil emulsion. In both heating modes, it was observed that the water content, temperature, and total applied energy are preponderant parameters regarding obtain higher efficiencies. The single mode heating required less energy to reach the same temperature and/or demulsification efficiency while the multimode provided better reproducibility. The power dissipation and, consequently, the microwave heating efficiency was dependent on the heating temperature and the emulsion water content. Furthermore, it was noticed that the presence of chemical additives tends to minimize any effect of irradiation mode on demulsification efficiency at temperatures above the 120°C.
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Obesity causes epigenetic alterations mediated by non-coding RNAs (ncRNAs) that increase susceptibility to autoimmune and inflammatory pathways. Obese individuals with rheumatoid ...arthritis (RA) are particularly affected, with worse clinical outcomes and treatment responses. In order to identify micro RNAs (miRNAs) and long ncRNAs (lncRNAs) that may influence RA development, progression, treatment efficacy, and clinical outcomes in obese individuals, we systematically screened PubMed, Web of Science, and Scopus databases for articles on these topics, published in the last decade. We ended up with 38 of initially 1110 documents and found that both obesity and RA share dysregulated expression of miR-21, miR-143, miR-146a, miR-155 miRNAs, H19, and HOTAIR lncRNAs (all but H19, up-regulated). With one exception (H19 and BMI in brown fat tissue), they correlated positively with clinical measures and disease activity. H19 and HOTAIR regulate 24 miRNAs, some differentially expressed in the investigated diseases. Both regulate miR-143-3p. We also investigated eleven GWAS-identified SNVs found in exonic lncRNA regions (there were none in exonic miRNA genes). Eight were associated with RA and three with obesity-related traits, seven change binding sites for miRNAs, especially on LINC01184 and GATA3-AS1, four were associated with gene expression in adipocytes (including LINC01184) and two may also change the secondary structure of ENSG00000284825 and LINC02656. These ncRNAs compose a unique regulatory network in obese RA patients, compiled for the first time in this review, which we suggest as future therapeutic targets in these simultaneous conditions.
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•We report the effect of microwaves and conventional heating on the crude oil.•Microwaves allowed us to remove water and acidic compounds from the oil phase.•Temperature and pH can be ...managed to alter the profile of acids recovered.
In this work, the application of microwave technology is investigated for breaking water-in-heavy crude oil emulsions focusing upon the identification of acidic species existing in the aqueous phase recovered by the microwave demulsification process. To accomplish this, a methodology for characterization of acidic species based on GC/qMS (gas chromatography coupled to mass spectrometry quadrupole type) has been developed. An experimental study was conducted to assess the effect of operating conditions, including the heating mode (microwaves/conventional heating), process time (30, 60min), pH of the aqueous phase (pH=2, 6, 10) and temperature (90, 120, 150°C) over the migration of acidic species from the crude oil to the aqueous phase during the demulsification of a heavy crude oil. The most influential variable was the temperature, which favors the partitioning of a larger number of acidic species, including cyclic compounds of low molecular weight that were not extracted at low temperature. The microwave heating allowed a wider distribution profile of monocyclic and bicyclic acids than the conventional heating scheme. Changing the aqueous phase pH from acid to the alkaline range modifies the profile of acidic compounds from predominantly acyclic to monocyclic and bicyclic species.
•Ammonium-based ionic liquids have surfactant properties.•Presence of amines in the ionic liquid decreases density and increases viscosity.•Amino groups present in the cation help to reduce surface ...and interfacial tension.•Increasing the cation alkyl chain length causes a decrease in interfacial tension.•Hydroxyls groups in the cation make it difficult to decrease the interfacial tension.
The demand for oil and gas resources has increased dramatically recently; therefore, residual oil recovery from previously under-exploited reservoirs has attracted significant attention. In this context, chemical methods are considered promising owing to their efficiency. Therefore, it is essential to identify new compounds that can enable residual oil recovery. Among the studied chemical compounds, ionic liquids (ILs) have been considered alternatives to commercial surfactants because of their notable properties, such as low vapor pressure, flammability, and chemical stability. Recently, several studies have reported new ILs as alternatives to commercial surfactants. However, only a few studies have been conducted on protic ionic liquids for this purpose. This paper presents the characteristics of three ionic liquids (ILs) based on ammonium cations and hexanoate anions, namely 2-hydroxyethyl ammonium hexanoate 2HEAHx, bis(ethyl)tri(ammonium) BHEAHx hexanoate, and bis(ethyl)tri(ammonium) hexanoate DETAHx. The physicochemical properties of pure ILs, including viscosity, density, and sound velocity, were measured over a temperature range of 298.15–343.15 K. Our results showed that adding a hydroxyl group to the cation increased the density of the IL. Moreover, the IL with the highest number of amine groups in the cation exhibited a lower density and higher viscosity. Among the three ILs studied, DETAHx exhibited the lowest critical micellar concentration of 235 ppm. All the studied ILs reduced the interfacial tension between substances with different polarities. The analyzed properties show that hexanoate-based ionic liquids are competitive for chemical applications concerning commercial surfactants.
Aprotic ionic liquids (C4pyr+NTf2-, C8mim+NTf2-, C8mim+OTf-, C8mim+PF6-, C8mim+BF4-, C12mim+NTf2-, and C12mim+Cl-) were successfully evaluated as viscosity modifiers, emulsion inhibitors, and ...demulsifiers. They are prone to be applied for the heavy oil production since such crude oil type potentializes some issues that are typically observed in the petroleum industry. Among them, it is worth highlighting the low flowability due to the oil's high viscosity. Also, high-viscous crude oil usually generates stable emulsions since they have high resins and asphaltene contents, which are interfacial-active. Thus, for operational and economic reasons there is a need for technologies that facilitate the improvement of the heavy-oil flowability as well as the demulsification process. Then, this work aimed to analyze the influence of the ionic liquid chemical structure (cationic alkyl length, cationic functional group, and anion type) upon the oil viscosity, emulsion inhibition or demulsification, at concentrations of 5 and 100 ppm (m/m). Two Brazilian heavy-oils were used for this study. Viscosity measurements of these oils at room temperature (25 °C) were made by an oscillatory rheometer before and after the addition of ionic liquid. Also, the emulsification inhibition and demulsification efficiency were analyzed by centrifugation. The results showed that the 1-dodecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide promoted a demulsification efficiency higher than 99%. In turn, the 1-butylpyridinium bis(trifluoromethylsulfonyl)-imide was the one that worked as an emulsion inhibitor. On the other hand, the interaction between the studied oils and some of the used ionic liquids enhanced the oil viscosity. All the evidence points out to the fact that it was caused by the asphaltene aggregation due to the formation of an ionic liquid-asphaltene molecular structure. The observed viscosity increase was of 11% for oil A and 7% for the oil B.
CO2 influence on asphaltene precipitation Cruz, Arley A.; Amaral, Monique; Santos, Denisson ...
The Journal of supercritical fluids,
January 2019, 2019-01-00, Letnik:
143
Journal Article
Recenzirano
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•NIR was applied to monitor the effect of CO2 content in the asphaltene precipitation at high pressure.•Experimental data were modelled with SRK-CPA EoS.•Effects of temperature, ...pressure, CO2 and model system composition were investigated on the asphaltene precipitation.
The energy industry has registered a considerable growth of petroleum production from reservoirs located in deep and ultra-deepwater, mainly in Brazil. The Brazilian Pre-Salt fields, specifically, have shown high carbon dioxide content which favors the precipitation of organic particles such as asphaltenes. This scenario has turned flow assurance into a major technical and economic challenge for the exploitation of those fields. In this work a variable-volume cell equipped with a near-infrared probe was used to study the onset of asphaltene precipitation induced by carbon dioxide, evaluating the effects of pressure, temperature, asphaltene concentration, and system composition. Furthermore, the Cubic Plus Association (CPA) was applied to model the asphaltene precipitation. The results show that temperature and the oil model system composition were the parameters that most influenced the asphaltene stability, and that the CPA adequately described the asphaltene precipitation.
The use of ionic liquids (ILs) as demulsifiers of water-in-crude oil emulsions represents a new field of study. The main purpose of this work is to investigate the effect of five ILs, C4mim+NTf2−, ...C8mim+NTf2−, C12mim+NTf2−, C4py+NTf2−, and C8mim+ OTf−, and a set of operation parameters on the demulsification process, including the heating type (conventional and microwave), IL concentration (0.74–8.9 μmol/g), effect of alkyl chain length, and effect of cation and anion type on demulsification efficiency. The results indicated that the demulsification was favored when more hydrophobic ILs and longer cation alkyl chains were employed, such as C12mim+NTf2−, reaching values close to 92% of water removal. Moreover, the joint use of microwaves and hydrophobic ILs allowed us to maximize the demulsification efficiency.
A common problem verified in the sucker rod pumping technique is fluid slippage, reducing pump efficiency (PE). Approaches relating to the influence of water cut, viscosity, and clearance on fluid ...slippage lacks discussions in the literature. Thus, this work aims to study the effect of these three parameters upon slippage and PE. Rheological analyses were carried out to determine emulsions viscosities. The obtained data were inputs parameters in the QRod-Echometer software. The results showed that clearance was the parameter that most influenced the pump efficiency, and for fluids with low viscosity, the PE will be optimized when clearance is reduced.
The asphaltene precipitation and deposition cause severe operational, economic, and environmental problems to the petroleum industry in all of its streams, such as pipe clogging, emulsion ...stabilization, and incrustation in separators. It is induced by temperature, pressure, and composition changes at crude oil production and refinement. The crude oil incompatibility is the main reason for asphaltene precipitation at refinery plants. Although it has been the subject of studies for the last 50 years, there is still a lack of robust and reliable tools that can detect and monitor the asphaltene precipitation online. In this scenario, the present work aims to use near-infrared spectroscopy to analyze the oil compatibility regarding asphaltene stability as well as to study the influences of pressure, temperature, and composition variation at desalter conditions. For this, a near-infrared spectrometer equipped with a transflectance probe connected to a variable volume high-pressure cell was used. The results showed that the temperature, pressure, and rate of flocculant agent addition on the crude oil presented a small influence on the asphaltene precipitation onset at the experimental range studied. The interaction among the compounds in oil blends was the only factor that changed the asphaltene stability level.
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