Crude Oil Emulsions Research Articles

Alginate-based poly ionic liquids for the efficient demulsification of water in heavy crude oil emulsions

This work deals with the synthesis, characterization, and application of alginate-based poly ionic liquids for efficient demulsification of water in oil emulsions. For the formation of renewable poly ionic liquid (PIL), sodium alginate (S.ALG) was converted to alginic acid (H.ALG), followed by an esterification process to produce corresponding polyester, (N.ALG). In the later stages, the formed N.ALG was subjected to a quaternization reaction using either 1-bromohexadecane or 1-bromononane in order to produce PILs (BH-ALG) and (BN-ALG), respectively. Then, the two formed PILs (BH-ALG and BN-ALG) were evaluated in terms of the chemical structure, surface and interfacial tensions, thermal stability, relative solubility number (RSN), and micelle size. While testing the efficiency of as-synthesized two PILs towards the demulsification of water in heavy crude oil (W/O) emulsions, both PILs were found to be efficient. Furthermore, an increase in efficiency was observed with the increase of PIL concentration and ratio of water in the emulsions. Among the two PILs, the BH-ALG displayed higher demulsification efficiency as against the BN-ALG, and this can be due to its higher hydrophobicity, and hence its ability to disperse in heavy crude oil as a continuous phase.

Crude oil emulsion breaking: An investigation about gravitational and rheological stability under demulsifiers action

Emulsions are common in the oil industry, being present in the extraction and production stages. Its formation occurs with the contact of brine and crude oil under intense flow. The presence of emulsified water (dispersed droplet size, φ ≤ 50 μm) in crude oil can negatively impact its exploration, transportation, and refining, making transportation more expensive, requiring more energy for heating, and causing equipment corrosion on all processes. In addition, crude oil has salts and sediments that encrust and corrode equipment of the primary oil treatment unit and distillation towers, also causing catalyst poisoning in the cracking step. Therefore, such components need to be removed for subsequent refining processes. To prevent these problems, the dehydration/desalting of crude oils is a strategy adopted to reach adequate values of water, salts, and sediments required in the refineries for the next steps after primary treatment. However, the emulsion breaking is influenced by several factors that affect the stability of crude oil (W/O emulsion), such as viscosity, contents of water, salts, sediments, and natural surfactants, among others. Given this perspective, this work investigated the stability of two different types of crude oils with demulsifier under the action of gravity (bottle test) and shear stress (rheology). The comparisons of gravitational and rheological techniques concluded that the shear stress sweep analyses are useful to evaluate the demulsifier performance in the emulsion breaking, being a reliable and fast methodology. Such studies allowed the identification of adequate parameters: temperature (80 °C) and, demulsifier type and quantity (500 ppm) for efficient crude oil phase separation, without using washing water. The physicochemical and rheological characterizations clarified the crude oil's colloidal stability behavior to understand the impurities' influence on the oils' properties (crude and desalted).

Synthesis and Evaluation of PEGylation of Poly(acrylate-maleic anhydride) as a Demulsifier for Crude Oil Emulsions

Synthesis and Evaluation of PEGylation of Poly(acrylate-maleic anhydride) as a Demulsifier for Crude Oil Emulsions

Demulsification of water-in-crude oil emulsion driven by a three-branch structure demulsifier

A three-branch structure demulsifier (GTE-DDA) for the treatment of water-in-crude oil (W/O) emulsions was synthesized by a one-step method using glycerol triglycidyl ether (GTE) as core and dodecyl amine (DDA) as branched chain. It was characterized by Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance hydrogen spectra (1H NMR) and thermogravimetric analysis (TGA). Some key parameters such as the concentration of GTE-DDA, settling time, operated temperature and salinity on demulsification efficiency (DE) were systematically explored. The DE reached 87.55% after treating with 400 mg/L of GTE-DDA at 50 °C for 30 min. The demulsifying temperature was significantly lower than those reported in literatures (60-80℃). Especially, a rise in temperature could further improved the DE. In addition, GTE-DDA had an excellent salt tolerance. The possible mechanism was investigated by the interfacial tension (IFT), three-phase contact angle (CA) and microscopic observation. The comparison with commercial demulsifiers showed that GTE-DDA had a great potential for the treatment of crude oil emulsions.

Stability of acid in crude oil emulsion based on interaction energies during well stimulation using HCl acid

Acid stimulation is one of the most common chemical approaches to overcome the reduction of crude oil production due to clogging of oil formation passages. Nonetheless, in this process, the formation of stable and tight acid in crude oil emulsions may lead to further unsolicited formation damage. In this study, the stability of dispersed HCl droplets with concentration of 15 and 28 wt % in a crude oil was characterized by means of the interaction energy theory. Similar experiments were repeated and compared with distilled water. The results showed that water droplets always tend to coalesce in short period of time, while acid droplets resist. This is due to the acid-base interaction energy, which is the most prevailing component among various interaction energies which would profoundly influence the stability of acid in crude oil emulsions. In case of using HCl solution as aqueous phase in the emulsion, this interaction between acid droplets overcomes the others, especially the attractive interactions. The most stable acid in crude oil emulsion would be formed in distances between the droplets shorter than 4 nm because acid-base interactions are short-ranged. For the investigated crude oil, it was also observed that the emulsion with HCl 28 wt % solution was more stable than that for HCl 15 wt %. Bottle tests also agreed qualitatively with the results of this theoretical approach. The practical implications of these results would be that overdosed acidizing with excessive injection rates may lead to unwanted formation damage due to formation of tight acid in crude oil emulsions. Finally, the presented results would serve as a guideline for comparing acids of different concentrations.

Effects of Asphaltene Concentration and Test Temperature on the Stability of Water-in-Model Waxy Crude Oil Emulsions.

In oil fields, the formation of water-in-waxy crude oil emulsion is inevitable. The dissolved/crystallized state wax can interact with asphaltenes and then greatly affect the emulsion stability. However, studies on this aspect are still insufficient. In this work, the effects of the test temperature (30 °C well above the wax appearance temperature (WAT) and 15 °C well below the WAT) and asphaltene concentration (0∼1.5 wt %) on the stability of the water-in-model waxy crude oil emulsions containing 10 wt % wax were systematically investigated. When the model crude oils contain no wax, the flowability of the oils is good and the asphaltene concentration has little influence on the oil rheology. Increasing the asphaltene concentration facilitates the adsorption of asphaltenes to the oil–water interface, thus reducing the interfacial tension and water droplet size while enhancing the interfacial dilatational modulus. The stability of the emulsions improves with the increase in the asphaltene concentration, but the emulsions are still unstable. When the model crude oils contain 10 wt % wax, the WAT slightly decreases from the initial 25 to 24 °C after the addition of asphaltenes. The oil rheology is greatly improved by the addition of 0.05 wt % asphaltenes. With the further increase of the asphaltene concentration, the improved rheological ability of the asphaltenes deteriorates rapidly. At the asphaltene concentration of 1.5 wt %, the oil rheology is dramatically aggravated. The stability of the emulsion containing 10 wt % wax is mainly controlled by two aspects: on the one hand, the dissolved-state wax (30 °C) could facilitate the adsorption of asphaltenes to the interface, further reduce the interfacial tension and the water droplet size, and enhance the interfacial dilatational modulus; on the other hand, the wax crystals precipitated in the oil phase (15 °C) can form a stronger network structure at relatively high asphaltene concentrations (0.5∼1.5 wt %) and then immobilize the water droplets. The above two aspects greatly improve the sedimentation and coalescence stabilities of the emulsions at 15 °C. In addition, we did not find persuasive evidence showing that the wax could crystallize around the water droplets and strengthen the oil–water interfacial films.

Comparability of in situ crude oil emulsification in phase equilibrium and under porous-media-flow conditions

HypothesisThe emulsification of water and crude oil is typically examined and optimized in test tubes by optical means, that is, mixed under turbulent conditions and detected outside the porous medium in equilibrium. In this study, we investigate the rather complex case of crude oil emulsification by alkaline solutions to assess whether the classical phase behavior experiments are representative of the emulsification under laminar flow conditions in porous media. ExperimentsWe characterized the phase equilibrium in the test tubes through X-ray attenuation in micro-X-ray computed tomography (μCT). Moreover, we showed that for these systems, the conventional qualitative optical inspection leads to considerable misinterpretation. X-ray attenuation ensures a quantitative analysis directly comparable to results from μCT-based core-flood experiments, where phase mixing occurs in porous media flow. The study was complemented with microfluidic experiments providing additional high-resolution information on emulsion phases. FindingsWe conclusively show that in the complex in situ saponification of crude oil by alkaline flooding, (a) the emulsifications in test tubes and in porous media flow are comparable, considering the displacement process in the latter; (b) a minimum emulsion volume with balanced compositions leads to optimal oil recovery in μCT-based and conventional core flooding and in microfluidics.

Braid-reinforced PVDF hollow fiber membranes for high-efficiency separation of oily wastewater

Several efforts to produce mechanically robust polymeric hollow fiber membranes have led to the use of polyethylene terephthalate (PET) hollow braided tubes, which offer rigidity to hollow fiber membranes. However, a compensation of flux exists with increased filtration pathway occasioned by braid substrate and thick polymer coating. It is often difficult to control the fabrication parameters to achieve uniformly coated and thin separation layer. In this work, we report a modification of the erstwhile dry-jet wet spinning process for braided hollow fiber by introducing a loop-system to increase resident time in the coagulation bath for effective solvent exchange and leaching of pore former additive. A combination of air gap (5, 15 and 25 cm), polymer concentration (15%, 17% and 19%) and take-up speed (1.2, 2.4 and 3.6 m/min) were varied to produce membranes with optimum filtration performance against crude oil emulsion feed. BRP-HM8 spun with 15 wt% PVDF, 15 cm air gap and take-up speed of 2 rpm exhibited thin and uniform coating outside of braid, well-developed pore structure resulting in high flux up to 620 L/m2h, good hydrophilic/oleophobic characteristics with > 98% rejection of crude oil as well high mechanical properties against harsh feed and elevated pressure.

Experimental verification of the effects of three metal oxide nanoparticles on mass transfer at gas-liquid interface

The application of nanomaterials in petroleum industry is becoming common. Nanofluids are used as the water phase in the process of water alternating gas injection. Previous studies mainly focused on the effect of nanoparticles on the pore throat properties of porous media or the effect of nanofluids on crude oil emulsification. However, in the process of water gas alternating displacement, the relative flow of water and gas affects the displacement front and gas breakthrough time. Therefore, it is significant to study the effect of nanoparticles on mass transfer at gas-liquid interface. Based on the good dispersion and unique physical properties of nanoparticles in the base solution, in the process of alternating injection of CO2 and water, water is used as the base solution and nanoparticles are added to form a uniformly dispersed nanofluid. In this study, the enhancement of mass transfer by nanoparticles at the gas-liquid interface was studied. The theoretical model of the micro mass transfer at the gas-liquid interface during the percolation of nanofluid and CO2 in porous media was deduced. Combined with the absorption experiment of CO2 mixture, the enhancement effect of nanoparticles on mass transfer process was verified. Different factors affecting CO2 absorption were also compared. The main fluids used in the experiment were deionized water, SiO2, TiO2 and Al2O3 nanofluids. The experimental results of different nanofluids show that TiO2 nanoparticles enhance the mass transfer most obviously, and SiO2 inhibits the mass transfer when the content exceeds a certain content. In addition, the optimum absorption concentrations of the three nanoparticles are in the range of 0.06–0.08 wt‰. Combined with the relative permeability experiment, the influence of nanoparticles on the law of gas-liquid relative permeability is further revealed. This experimental result provides a theoretical guidance for the application of nanoparticles in enhancing oil recovery.

Reversible stability of colloids switched by CO2 based on polyhexamethylene guanidine.

The stability of a colloid, including emulsion and polymer latex, can be destroyed irreversibly by the addition of salt. Using the CO2 stimulus, amines can be converted into organic ammonium salts reversibly, which can access the switching of colloids. Polyhexamethylene guanidine (PHMG), was chosen as a switchable amine. The conductivity of PHMG aqueous solution switched by adding and removing CO2. Surface tension measurements verified that, under CO2, the critical micelle concentration of sodium dodecyl benzene sulfonate (SDBS) decreased from 1.0 × 10-3 to 5.0 × 10-4 M with the addition of PHMG. The crude oil emulsion containing SDBS and PHMG was destroyed and restored reversibly by the treatment with CO2 and N2. The polystyrene latex also occurred an obvious stratification after sparging with CO2 and returned a homogeneous phase upon bubbling N2. This study is intended to pave the way for colloids which has reversible stability in response to CO2 stimulation.

Chemical demulsification techniques in oil refineries: A review

During oil production and pipeline transmission, water–oil emulsions form due to pressure and shear forcesWhen water or brine droplets are continually spread across crude oil, water-in-oil (W/O) emulsions form. Other emulsions, such as those produced of crude oil droplets suspended in brine or water (O/W), are uncommon. When crude oil is removed from a reservoir, it is contaminated with sediments and water, among other impurities. Natural emulsifiers include resins, asphaltenes, waxes, crude particles, and carboxylic acids. At the water–oil interface, some of these components may clump together, generating a stable film surrounding the droplets, by preventing water droplets from clumping, this film aids in the formation of a stable w/o emulsion. Water and crude oil production could raise a number of concerns. This could include the cost of pumping or transporting water via tanker or pipeline, as well as manufacturing facility corrosion. Chemical demulsification is the process of destabilizing the shielding interfacial layers with chemicals, resulting in a quicker emulsion breakdown rate. As a cost-effective and effective method of dewatering crude oil emulsions, chemical additives are frequently used.

Demulsification of crude oil emulsions using ionic liquids: A computational intelligence approach

Ionic liquids have enormous applications in various areas of technology. Among their usage is for the destabilization of crude oil emulsions produced in oilfields. Herein, we propose a support vector regression (SVR) based model for smart screening and prediction water/oil separation driven by ionic liquids demulsifiers. The proposed SVR model applies attributes such as crude oil-water volumes, asphaltenes/resins content, emulsification speed/time, demulsification temperature, ionic liquid concentration, ionic liquid molecular weight, and demulsification time to predict the extent of demulsification performance of representative ionic liquids. Accordingly, the predicted demulsification efficiencies of the assessed ionic liquids exhibited significant matches with the experimental results. The developed approach demonstrated excellent accuracy as indicated by the root mean square error (RSME) values: 4.0123 and 19.6478 for the training and testing datasets, respectively. Additionally, the model demonstrated a considerable correlation coefficient (R2): 97.86 % and 75.97 % for the demulsification efficiency of tested ionic liquids in the training and testing datasets, respectively, thereby consolidating an appreciable agreement between the measured and the predicted results. It is envisaged that the SVR model employed in this study would greatly enhance the smart screening of ionic liquids used for demulsification activities in the petroleum and other related industries.

APPLICATION OF Dalbergiella welwitschii LEAVES EXTRACT IN THE DEMULSIFICATION OF WATER-IN-OIL EMULSIONS

The application of Dalbergiella welwistchii leaves extract in breaking a crude oil and water Emulsions was studied. n-Hexane, methanol and distilled water extracts of the leaves were prepared using soxhlet extraction method. The extracts were characterized with GC-MS and the components of the extracts show the presence of lupeol, campesterol, methandrostenolone,butylgallate, terpineo, glycylglycine, n-butoxycarbonyl-, pentafluorophenylmethyl ester, taxifolin, 2-Oxabicyclo[2.2.1]heptan-3-one, 1,7,7-trimethyl-, innossitol, p-cymene, (E)-3(10)-Caren-4-ol, 2,4(1H,3H)-Quinazolinedione, 1-methyl-, quercetin 3’-methyl ether, phenol, coumarin, mesitylene, campesterol methyl ether, terpinen-4-ol, bis(2-butyoxyethyl) phthalate, cyclohexane, 1-methyl-2-propyl-, 2-tolyloxirane, (E)-3(10)-Caren-4-ol, sulfurous acid, 2-ethylhexyl nonyl ester, p-cymene, diethyl benzamidomalonate, fumaric acid nonyl trans-hex-3-enyl ester, 1,1'-diacetoxy-4,4'-dichloro- 5,5',8,8'-tetramethoxy -6,6'-dimethyl-2,2'-binaphthalene, bicyclo[4.2.0]oct-1-ene,7-exoethenyl-, 1,3-cyclopentadiene,1,2,3,4-tetramethy-5-methylene-, 2,2'-bithienyl, 5,5'-bis(trimethylstanyl)-, α-d-glucofuranosyl benzenesulfonate, benzaldehyde, 2H-benzo[f]oxireno[2,3-E]benzofuran-8(9H)-one,9[[[2-(dimethylamino)ethyl] amino] methyl] octahydro-2,5α-dimethyl-, ethyl iso-allocholate, androstane-11,17-dione, 3-[(trimethylsilyl)oxy]-, 17-[O-(phenylmethyl)oxime], (3α,5α)-, 1-Isopropoxy-2,2,3-trimethylaziridine (sin) in various percentages in all the extracts. Basic water percentage test of the emulsion shows that the emulsion contained 65.2% water. The various extracts were prepared as demulsifiers and subjected to demulsification test using different concentrations at room temperature for 60 minutes. A synthetic demulsifier was employed for comparison using the total volume of water separated as a yardstick. Results show that n-hexane extract and methanol extract demulsifiers were able to break water-in-oil Emulsions and these were attributed to the phytochemical components of the extracts while the distilled water extract demulsifier was unable to break the emulsion. The commercial demulsifier employed resolved the emulsion with a percentage higher than that of the n-hexane extract and methanol extract formulated demulsifiers. This was attributed to the dehydrating and other chemical components used in preparing the synthetic demulsifier.

Preparation and demulsification performance of modified attapulgite nanoparticle demulsifier

By chemically modifying the attapulgite (AT) using 3-Aminopropyl triethoxysilane (APTES), stearic acid (STA) and/or octadecyl trichlorosilane (OTS), AT-APTES, AT-APTES-STA and AT-OTS nanoparticle demulsifiers were prepared. The structure and morphology of the prepared materials were characterized and analyzed by FT-IR, SEM and Zeta potential. Contact angle characterization and the distribution of nanoparticle materials in the oil-water mixture showed that the AT-APTES-STA nanomaterial has good amphiphilicity and interfacial activity. The demulsification performance of various NP demulsifiers was investigated by using bottle test method. The results showed that the AT-APTES-STA nanoparticles can achieve rapid and efficient demulsification of the crude oil emulsions at room temperature in a wide pH range from acidic to weak alkaline. The increase of demulsifier dosage and demulsification temperature was helpful to improve the demulsification efficieny. However, the influence of temperature on the demulsification efficiency was limited, and good demulsification efficiency could be obtained at room temperature. Under the conditions of demulsifier dosage 900 ppm, pH 7 and temperature 25℃, the demulsification efficiency of AT-APTES-STA was as high as 96.7%. In contrast, the AT-APTES had a poor demulsification efficiency, while the AT and AT-OTS materials basically do not have the demulsification ability. By comparing the demulsification performance and the chemical structure of these modified attapulgite nanoparticles, it was concluded that a NP demulsifier with excellent demulsification performance should have the following two basic characteristics: (a) good amphiphilicity and interfacial activity; and (b) enough surface functional groups that can strongly interact with the emulsified molecules. It is believed that this work is of great significance to the design and preparation of NP demulsifiers for the crude oil emulsion.

Continuous Separation Process of Water-in-Crude Oil Emulsion by Simultaneous Application of an Electrical Field Combined with a Novel Absorbent Based on Functionalised PolyHIPE Polymer

During the extraction process of crude oil, the removal of water from a high stability water-in-crude oil emulsions is life-threatening for the production of a profitable product. However, several technologies of separation exist today, e.g. stripping columns, centrifugal separators, coalescence separators, vacuum distillation systems and gravity separators, almost all of these approaches are not able to completely remove water from water-in-crude oil emulsions besides their high cost.
 In this study, the preparation of a high internal phase emulsion (HIPE) was achieved on a laboratory scale. Subsequently, it was polymerized and sulphonated to produce a hydrophilic macroporous polyHIPE polymer (PHP) called silane (vinyl trimethoxy silane) PHP with a relatively high surface area of 104 m 2/g. It demonstrates high water absorption capability in addition to its ability to remove surface active substances such as Mg, Ca, Na and Cl, from crude oil which cause crude oil emulsification.
 The rates of demulsification of water-in-crude oil emulsions were examined in high AC field under various emulsion inlet flow rates from 100 ml/min to 1500 ml/min and different applied voltages from 1-5 kV (equivalent to 14-69 kV/m) by using a model of an electrostatic separator combined with silane PHP as absorber. It was found that the best separation efficiency was 91% with applied voltage of 5 kV and emulsion inlet flow rate of 100 ml/min. When the spent silane PHP was reused in the demulsification process under similar conditions, a separation efficiency of up to 73% was achieved. Also, it was noticed that the separation efficiency was increased with the increase in applied voltage and reduction in the inlet flow rate of emulsion. Moreover, the original or spent silane PHP were able to remove the undesired metals present in the crude oil.
 Keywords: Demulsification; Emulsion flow rate; Separation efficiency; Electrostatic Separator; Electric field strength.

Experimental study on the performance of emulsions produced during ASP flooding

ASP (Alkaline/Surfactant/Polymer) flooding is one of the most promising techniques that has proven to have successful application in several laboratory and pilot tests. However, the formation of persistent and stable emulsions is one of the associated problems with ASP flooding. The present work investigated the effect of sodium carbonate alkaline, Alpha Olefin Sulfonate (AOS) surfactant, and GLP100 polymer on produced crude oil emulsion. The study was conducted by measuring the emulsion stability in terms of water separation and rag layer volume using a TurbiScan analyzer, the dispersed droplet size using cross-polarization microscopy, the interfacial tension using spinning drop tensiometer, and rheological properties using rheometer. The experimental results have shown that AOS presence increased the emulsion stability only when its concentration is above 100 ppm. Meanwhile, below 100 ppm, the presence of AOS promoted water separation and reduced the rag layer volume. In a less significant manner, a high concentration of sodium carbonate alkali increased the stability of the emulsion. The use of GLP100 Polymer has shown substantial ability in promoting water separation and reducing the rag layer volume to a minimal level. It is believed that the outcomes of this work will aid in developing a suitable destabilization process to enhance the oil–water separation and produced water treatment from ASP flooding in the oil production fields. Further investigations on AS, AP, SP as well as the ASP's combined effect on emulsion stability, droplet size, interfacial tension and rheological properties are highly recommended to support the decision-makers on the EOR implementations with chemical additives.

Investigations of crude-oil emulsions at the micro-to-nano scales

The removal of the micro droplets of emulsified water from crude oil causes high cost and energy. In this paper we show that cryo electron microscopy (cryo-EM) imaging of micro and nano emulsions prepared from United Arab Emirate based crude oil provides critical information on their stability. Specifically, the cryoSEM imaging analysis applied to emulsion of murban-2019, and upper zakum-2019 crude-oils allowed determining naturally occurring surfactants in these crude-oils. Moreover, the applied method also turned out to be an efficient way to qualitatively investigate the effect of synthetic surfactant on the stability of the emulsions. The high resolution cryoTEM imaging analysis of emulsions from upper zakum-2019 sample enabled visualizing “bilayer” of naturally occurring surfactants, presumably the asphaltene. The cryoTEM analysis further allowed estimating the volume-fraction of emulsified water in the crude-oil at nanoscales and turned out to be about 1% for the upper zakum-2019 samples.

Synthesis and application of novel gemini pyridinium ionic liquids as demulsifiers for arabian heavy crude oil emulsions

Ionic liquids (ILs) are environmentally friendly compounds and their gemini types exhibit high thermal stabilities and high surface and interfacial activity. The main objective of this work is to prepare, characterize and investigate the demulsification efficiency of two gemini pyridinium surfactant ILs. They were prepared by the introduction of long chain decanoyl chloride to aminopyridine followed by quaternization with two dichloro spacers containing different ethylene oxide units (DCDE and TEGDC) to form MEGPy and TEGPy ILs, respectively. The structure properties of the prepared demulsifiers were investigated using different spectral tools including 1HNMR and 13CNMR and DLS. Also, their solubility and surface activity were investigated to confirm their ability to reduce surface tension (ST) and interfacial tension (IFT). Gemini pyridinium IL with triethylene oxide spacer (TEGP) showed higher ability to reduce both ST and IFT than that with mono ethylene oxide spacer (MEGP). Thanks to the ability of both TEGPy and MEGPy surfactant IL to reduce ST and IFT, they were applied successfully as demulsifiers for W/O emulsions with different water percentages. Demulsification study indicated that both TEGPy and MEGPy were able to demusify W/O emulsions with high performance which reached to 100% at low concentrations (250 ppm) for some compositions with higher activity to TEGP IL than MEGPy surfactant.

Effect of Polar Molecule Aggregation on the Stability of Crude Oil/Water Interface: A Molecular Simulation Study

Abstract To ensure the efficient operation of crude oil dehydration and sewage treatment technology in oilfield surface production system, the effect mechanism of polar components represented by asphaltene and resin on the formation and stability of oil-water emulsion needs to be revealed at nanoscale. In this paper, the molecular dynamics simulation method was used to construct the crude oil/polar component/water system models with different molar ratios of asphaltene to resin by adjusting the number of asphaltene and resin molecules, so as to reveal the molecular arrangement and aggregation process and film forming characteristics of asphaltene, resin, and their mixture at the oil-water interface. The simulated results showed that the aggregation process of asphaltene molecules under the influence of hydrogen bonds can be divided into three stages. The addition of resin molecules enhanced the connection between molecules of all polar components at the interface. The π−π stacking and T-shaped stacking structures were found in all aggregations, and the higher the molar ratio of asphaltene molecules, the higher the proportion of π−π stacking structure. With the increase of the molar ratio of asphaltene to resin increases from 0 : 1 to 1 : 0, the interfacial film thickness and interface formation energy increase from 2.366 nm and -143.89 kJ/mol to 3.796 nm and -304.09 kJ/mol, respectively, which indicated that asphaltene molecules play a more significant role in promoting the formation of interfacial film and maintaining its structural stability than resin molecules. The investigations in this study provide theoretical support for demulsification of the crude oil emulsion.

Synthesis of novel demulsifier nano-materials and their application in the oil industry

Nanotechnology is a scientific discipline that has a wide range of applications in practically every aspect of modern life, particularly in the fabrication of nanomaterials and nanocomposites. Due to the importance of this sector economically and in terms of energy supply, one of the most important applications of nanomaterials is their large scale use to remove or minimize the hurdles that the oil and gas industry faces. The hydrothermal method was used to prepare novel Rhodium borate nanoparticles, which were made by first obtaining Rhodium oxide from Rhodium acetate, then reacting with boric acid and other cofactors. The efficiency of the process for generating Rhodium borate nanoparticles was extremely high. The efficiency of the process for generating Rhodium borate nanoparticles was extremely high. The validity of the obtained results was confirmed by the diagnostic and estimation procedures utilized in this work (XRD, FT-IR, SEM, and TEM). One of the most critical processes in petroleum processing is demulsification. To avoid issues during oil transportation and handling, oil emulsions must be broken down. Because of the water content and dissolved salts in the aqueous phase of the emulsion, the presence of water in the crude oil is undesirable and can lead to pipeline corrosion and increased transportation costs. The physical and chemical features of crude oil from the Halfaya oil field in southern Iraq, which is known to contain a certain percentage of water, have been investigated. Rhodium borate (Rh2O3. B2O3·H2O) (DF1) nanoparticles were utilized in this work to separate water from crude oil emulsions. Effective aggregates exist in the synthesized Rhodium borate nanoparticles, allowing them to operate as demulsifying agents. The separation of water from the emulsion by the produced rhodium borate (DF1) and the standard demulsifier (RP96BQ) used in the same oil field at constant temperature (60 °C) and with varying concentrations was compared in this study using crude oil samples. A high separation efficiency was obtained for the prepared nano demulsifier with a percentage of up to (84.2%) compared with the standard demulsifier (RP96BQ).