Demulsification Tests Research Articles

Demulsification of Water-in-Crude Oil Field Emulsion Using Green Demulsifier Based on Sesamum indicum: Synthesis, Characterization, Performance, and Mechanism

Summary This paper addresses the issues related to poor demulsifier efficiency, low biodegradability, and toxicity of commonly used chemical demulsifiers in the petroleum industry. To overcome these challenges, this study proposes an environmentally friendly demulsifier synthesized from Sesamum indicum (sesame oil). The synthesized demulsifier is characterized using Fourier transform infrared (FTIR), nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). The demulsification test was performed for the synthesized demulsifier through the standard bottle test method using water-in-oil field emulsion. The results indicate that the demulsifier has an excellent dehydration rate and can achieve a demulsification efficiency of 85% within 10 minutes at a concentration of 200 ppm and 100% efficiency in 60 minutes at 70°C and performs better than the commercial demulsifier. The paper summarizes the factors affecting the demulsification process, including settling time, temperature, and demulsifier concentration. Furthermore, the demulsification mechanism is explained through interfacial tension (IFT) measurement, competitive adsorption test between asphaltene and demulsifier, and rheology study of emulsion. Moreover, the disuccinimidyl sulfoxide (DSSO) demulsifier is tested for its biodegradability according to Organization for Economic Co-operation and Development procedure, and the results show that it is completely biodegradable. The outcome of this research provides a promising solution for the demulsification of field emulsions through eco-friendly and efficient demulsifier.

Fluorinated polyether-coated Fe3O4-functionalized oxidized carbon nanotubes as a recyclable demulsifier for crude oil emulsion treatment.

Based on the excellent adsorption properties of carbon materials, a new magnetic nanodemulsifier was prepared in this study. First, carbon nanotubes were oxidized using a solvothermal method. Then, Fe3O4 was combined with oxidized carbon nanotubes using a one-pot method, and then grafted onto fluorine-containing polyether to prepare a magnetic composite demulsifier (Fe3O4@C-F) with good demulsification properties. The surface morphology of the composite demulsifier was analyzed using scanning electron microscopy (SEM). The structure of the composite demulsifier was characterized using Fourier transform infrared (FTIR) spectroscopy and X-ray photoelectron spectrometry (XPS). The stability of the composite demulsifier was characterized using thermogravimetric analysis (TGA). Results showed that the oxidized carbon nanotubes and fluorinated polyether were successfully attached to Fe3O4. The experimental objective was to obtain a self-made crude oil emulsion. The demulsification test and recovery performance test were then performed, and the main factors affecting the demulsification performance of the demulsifier were investigated. Results showed that when the dosage was 800 mg L-1, the temperature was 65 °C, the demulsification time was 90 min, and the pH value was 6. The demulsification effect of the Fe3O4@C-F magnetic composite demulsifier was the best, whereby the demulsification rate could reach 91.68%, and the oil-water interface was clear. Fe3O4@C-F had a magnetic response and could be recycled from the two-phase system six times under the action of an external magnetic field. Fe3O4@C-F is an efficient and environmentally friendly demulsifier that has important application value for enriching demulsification technology systems.

A gemini ionic liquid and its low-temperature demulsification performance in water-in-crude oil emulsions

In the demulsification process of crude oil emulsions, the temperatures of above 60 °C are most commonly required. In this work, a gemini ionic liquid (PGE-TFA) with amphipathy and interfacial activity was prepared by a simple and safe method, which could be used at the temperature of 40 °C for the effective demulsification of crude oil emulsions. The chemical structure and thermostability was investigated by FTIR, 1HNMR and TGA. The demulsification tests of PGE-TFA showed that it had higher demulsification efficiency (DE) and faster demulsification rate than common commercial demulsifiers. PGE-TFA could be used at a low temperature of 40 °C, a wide pH range and high salinity. The DE reached as high as 95.53 % in water-in-oil emulsions with the concentration of 500 mg/L at 40 °C for 90 min. The temperature of 70 °C could slightly increase the DE and significantly improve the demulsification rate, and the DE of 97.72 % was obtained with the same concentration for 30 min. In addition, the demulsification mechanism was investigated by dynamic interfacial tension, competitive adsorption and zeta potential. The results displayed that PGE-TFA had amphipathy and interfacial activity, which promoted it quickly diffuse to the oil-water interface and displace asphaltenes at the interface. Therefore, an unstable composite film could be formed at the interface and the interfacial tension was lowered, which induced the demulsification of the emulsions.

Demulsification of amphiphilic gemini ionic liquids and its demulsification mechanism

This work aims to prepare two new amphiphilic and interfacial active gemini ionic liquids to treat crude oil and investigates its demulsification mechanism. Tetraethylene glycol was pretreated with thionyl chloride and used as a linker to connect succinimide or phthalimide, and then reacted with dodecyl benzene sulphonic acid to obtain the corresponding amphiphilic and interfacial active gemini ionic liquid STA or PTA, respectively. 1H nuclear magnetic resonance spectroscopy (1HNMR) and Fourier-transform infrared spectroscopy (FTIR) was used to determine the chemical structures. The demulsification tests showed the demulsification efficiency with 150 mg/L of STA or PTA at 60 °C for 30 min was 99.89% and 99.79%, respectively. Furthermore, the demulsification mechanism of STA and PTA were studied and the prominent demulsification ability of STA and PTA were attributed to the better interfacial activity and amphipathy which could destroy the asphaltenes interfacial film. These results showed that STA and PTA had excellent demulsification efficiency, which promised application in petroleum industry.

Effect of Magnetic Graphene Oxide on Heavy Oil Demulsification

Chemical demulsification is the most efficient demulsification approach that can attain the desired separation efficiency and meet the environmental regulation standards whilst impose minimal economic burden on the petroleum industry. However, current demulsification methods using chemical demulsifiers suffer from significant secondary pollution, particularly after the demulsification process. Therefore, in this work, magnetic graphene oxide (MGO) was synthesized by a one-step co-precipitation method from graphene oxide (GO). The properties of MGO were then characterized by X-ray diffraction and Fourier transform infrared. MGO was successfully synthesized and used as the demulsifier for diluted heavy oil emulsions. Different MGO concentrations (40, 80, 120, 160, and 200 ppm) were used at different water cuts (20:80, 30:70, 40:60, 50:50, and 60:40 v/v%). Demulsification tests using the bottle test method indicated that MGO could separate the emulsions up to 99.98% efficiency due to the high surface area-to-volume ratio of nanoparticles and magnetic features, which enhanced the adsorptive capacity for separating water from the oil. The residual oil content in the separated water was then analyzed by an ultraviolet-visible spectrophotometer. The oil concentration in the separated water reduced to 398.8 mg/ml, corresponding to a demulsification efficiency of 99.98% observed at 40 ppm MGO concentration. The interfacial tension of the emulsions during demulsification was also analyzed, where the interfacial tension decreased with increasing MGO concentration.

Synthesis of modified natural polysaccharides for demulsification and corrosion inhibition

Oilfield chemicals play an important role in oilfield drilling, well completion, water injection, enhanced oil recovery, and gathering and transportation. The development of novel, environmentally friendly, multifunctional oilfield chemicals is an urgent research direction. In this study, two hyperbranched natural polysaccharides (AH and EH) were synthesized by modifying the biodegradable natural polysaccharide chitosan. AH and EH molecules contain a large number of polar groups, which interact with iron and adsorb on the iron surface, thus inhibiting corrosion. At the same time, the hyperbranched structure has a good bridging and aggregation effect on the dispersed phase in the emulsion, so as to achieve demulsification. In accordance with the strong fluorescence effect of crude oil, laser confocal microscopy was used instead of optical microscopy to observe the microscopic morphology of water-in-oil (W/O) emulsions. The demulsification tests indicate that the highest dehydration efficiencies of 86.24 % (AH) and 82.15 % (EH) were attained at a concentration of 500 mg L−1. The maximum corrosion inhibition efficiencies [90.24 % (AH) and 88.55 % (EH), at a concentration of 500 mg L−1] were calculated by weight loss experiments, micromorphology analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy. Quantum chemical theory of the two natural polysaccharides was applied to further interrogate the molecular space structure. Laboratory test results indicate that the modified natural polysaccharides AH and EH exhibited good demulsification performance for W/O emulsions, and substantially inhibited the corrosion of carbon steel in brine. This study provides new ideas for developing natural polysaccharides as environmentally friendly, multifunctional oilfield chemicals.

Preparation and characterization of nano-demulsifier ZIF-8@CNTs based on MOFs for O/W emulsion demulsification

Oil in water (O/W) and water in oil (W/O) crude oil emulsions have caused many production safety hazards and environmental problems, which have attracted widespread attention. In this article, an amphiphilic nano demulsifier ZIF-8@CNTs was prepared by solvothermal method based on the metal-organic frameworks (MOFs) and carbon nanotubes (CNTs). Scanning electron microscopy (SEM) and infrared spectroscopy (FT-IR) showed that ZIF-8@CNTs were grape dendritic, and ZIF-8 was successfully combined with OX-CNTs. Thermogravimetric analysis (TGA) showed that ZIF-8@CNTs had good thermal stability. The demulsification test showed that the demulsification rate could reach 99.4% when ZC-1 was added at 500 mg/L for 30 min at room temperature. The demulsification mechanism was studied by interfacial tension and interfacial activity experiments.

Freshly Milled Quartz Particles Obtained from River Sand as an Efficient Natural Demulsifier for Crude Oil Emulsions

Saline water necessarily contained in crude oil forms complex and stable water-in-oil (w/o) emulsions with oil. Due to the negative impact of this emulsion on the oil’s transportation and refining, special materials are added to help break the emulsion and separate water. Herein, a comparative study of the demulsifying ability concerning w/o emulsion of the original and freshly milled quartz (FMQ) particles isolated from river sand was carried out. The effect of quartz with a mesh size of 75 μm on reducing emulsion stability was investigated using rheological measurements, interfacial tension measurements, demulsification tests, as well as routine methods for characterizing solid and liquid materials. With the addition of 3 wt% FMQ, 97% demulsification efficiency was achieved after 100 min of settling, against 140 min for the original quartz. The role of milling quartz is to increase the ability of water to adhere and thus locally increase the pH value; this results in a reduction in the stability of the emulsion and its destruction. The prolonging effect of quartz milling lasted about 2.5–3.0 h, after which the demulsifying ability of milled quartz became comparable to that of the starting material.

Emulsification Characteristics and Electrolyte-Optimized Demulsification of Produced Liquid from Polymer Flooding on Alaska North Slope

Summary The first-ever polymer flooding pilot test is currently implemented in heavy oil reservoirs on Alaska North Slope (ANS). One of the major concerns of field engineers is the impact of polymer on oil/water separation after polymer breakthrough. This paper aims to predict the influence of polymer on emulsification characteristics of produced liquid and seek a cost-effective method to treat the produced liquid from polymer flooding. In this study, emulsions, at moderate and vigorous shearing conditions, were prepared by mechanically mixing 25 vol% of the ANS heavy oil with 75 vol% of the polymer solution. Bottle test method, microscope, and pendant drop technique were utilized to investigate the effect of polymer on emulsification characteristics in terms of separation behavior, drop size distribution (DSD), and interfacial properties [i.e., interfacial tension (IFT) and interfacial dilational rheology], respectively. As for chemical demulsification, the performance and interfacial behavior of four commercial demulsifiers and an inorganic salt, that is, potassium chloride (KCl), was measured using simulated produced liquid. The bottle test results demonstrated that polymer could enhance the emulsion stability, resulting in a slower separation rate, poorer water quality, and greater thickness of the intermediate layer. The pendant drop measurements showed that the IFT and interfacial dilational rheology were independent of polymer concentration. Thus, the stabilization effect of the polymer was mainly attributed to the increased viscosity of the continuous phase and the decreased drop size of the dispersed oil phase. As for the chemical demulsification tests, compound demulsifier E12 + E18 exhibited the best demulsification performance as well as the lowest IFT and interfacial elastic modulus. Nevertheless, a multifold dosage of E12 + E18 was required to demulsify the emulsion under vigorous mixing, leading to a potential increase in the chemical cost. A less expensive electrolyte, KCl, was able to work synergistically with demulsifier E12 + E18 to promote oil/water separation and reduce the demulsifier usage. In this proposed demulsifier formula, the mechanism for the effectiveness of the commercial demulsifier was its destructive effect on the interfacial film, while the effectiveness of KCl was mainly dependent on its viscosity reduction effect on the continuous phase. This study illustrates the intermediate layer elimination, and the water quality is the major challenge for produced liquid from polymer flooding and provides both practical and theoretical guidance in advance for the corresponding demulsification strategy of the produced liquid from the ongoing first-ever polymer flooding pilot on ANS.

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.

Recyclable amine-functionalized carbon nanotubes for the separation of oily wastewater

In this work, a CNTs-NH2 demulsifier was prepared by grafting ethylenediamine on the surface of carbon nanotubes to break oily wastewater. The physicochemical and interfacial properties of CNTs-NH2 were characterized and analyzed. It showed that CNTs-NH2 had an eminent amphipathicity and high interfacial activity, which allows it to sharply migrates to the interface and effectively interacts with interfacial film by the combined action of π-π interaction and electrostatic attraction. The demulsification tests exhibited that CNTs-NH2 could effectively remove emulsified oil from the oily wastewater. It could be used at acidic and neutral conditions, and high salinity. Moreover, it could be recycled and still maintained its interfacial activity, thusly vastly enhancing the application scope. The light transmittance was up to 88.1% and the corresponding oil removal rate was 99.2% with 100 mg/L of CNTs-NH2 for 30 min. The oil removal rate of CNTs-NH2 remained above 97.8% after 6 cycles. This work provides a deep understanding on the design of demulsifier and its demulsification mechanism.

Monolayer grafting of APTES modified graphene oxide on silica coated magnetite: Synthesis, characterization and application in heavy oil removal

Petroleum industries have been creating negative environmental and ecological impacts due to the formation of oilfield produced water (OPW) during refining processes. Graphene oxide (GO) as a chemical demulsifier was found non-recyclable; hence, it could cause environmental pollution. Thus, magnetic graphene oxide (M-GO) was proposed to prevent any possible contamination. In this work, GO, and M-GO were successfully synthesized and the produced M-GO composites were found coated with silica-coated magnetite (Fe3O4@SiO2) nanoparticles. As such, they possess excellent superparamagnetic properties. The demulsification tests demonstrated that 0.25 wt% of M-GO aqueous suspension achieved 98.53% of demulsification efficiency on the as-prepared crude oil-in-water emulsion, which was more superior than GO as the suspending oil floccules attached to M-GO can be separated effectively using magnetic separation. The optimizations of the demulsification process were conducted, and significant findings were included as the major novelty of this work. The recycling tests have proven that M-GO can be reused to perform demulsification effectively for ten times. Despite being able to reduce the demulsification costs in the industry, this research suggests that the excellent properties of M-GO can minimize the risk of polluting the environment due to leakage of demulsifier through the application of magnetic separation.

Carbon nanotubes grafted with β-cyclodextrin by an ultrasonication method and its demulsification performance in oily wastewater

Emulsified oily wastewater has caused many problems in industrial production and ecological environment. To address this challenge, carbon nanotubes grafted with β-cyclodextrin (MCNT@β-CD) was prepared by an ultrasonic method to break oily wastewater. The composite materials were characterized by Fourier transform infrared spectroscopy, UV-visible spectroscopy, scanning electron microscope and thermogravimetric analysis. The demulsification test showed that the light transmittance of the resulting water phase was up to 94.5% at a low concentration of 50 mg/L within a few minutes at room temperature. Also, the corresponding oil remove rate was about 99.76%. In addition, it was suitable for acidic and neutral conditions with good salt tolerance. Interfacial activity, wettability, self-assembly at oil/water interface (WOI), dynamic interfacial tensions, zeta potential and photomicrograph were further investigated to confirm the possible mechanism. Generally speaking, the surface wettability of carbon nanotubes could be turned with β-CD. Therefore, MCNT@β-CD might rapidly migrate to WOI and replace the asphaltenes by π–π interactions and reduce the emulsion stability by charge neutralization. The current work provides a significant understand for the demulsification mechanism and indicates that MCNT@β-CD is a favorable interfacial activity, high demulsification efficiency and non-toxic demulsifier for oily wastewater.

Functionalized graphene oxide with core-shell of Fe3O4@oliec acid nanospheres as a recyclable demulsifier for effective removal of emulsified oil from oily wastewater

Oily wastewater treatment has been proved to be one of the most crucial environmental concerns. In the present study, in the first step, hydrophobicity properties of Fe3O4 nanoparticles were modified by oleic acid (OA) to form Fe3O4@OA. Afterwards, graphene oxide (GO) nanosheets were functionalized with Fe3O4@OA nanocomposite to synthesize novel superhydrophobic nanosheets of Fe3O4@OA/GO. Synthesized Fe3O4@OA/GO nanocomposite was employed as a fast, recyclable, high performance, cost-effective, and environmentally friendly nanodemulsifier to eliminate oil from oily wastewater. Demulsification performance of synthesized GO-based nanodemulsifiers was measured using bottle test as a function of dosage of nanodemulsifier, temperature, pH, and settle time. Mechanism of demulsification was investigated through optical microscopy. Finally, adsorption isotherms of asphaltene molecules and synthesized nanodemulsifiers were studied so as to achieve detailed and precise understanding regarding interaction between nanodemulsifiers and molecules of asphaltene. Demulsification tests revealed that Fe3O4@OA/GO nanodemulsifier with excellent demulsification performance (99.99%) had the ability to separate oil/water emulsion quickly, with demulsification capability for 6 recycle times.

Improving the emulsion stability by regulation of dilational rheology properties

Considering the importance of interfacial film in determining emulsion stability, it is of great significance to reveal the relationship between the emulsion stability and rheology properties. Herein, we first investigated the dilational rheology properties of the imidazolium Gemini surfactants ([Cn+2-3-Cn+2im]Cl2) by the oscillating drop method, and the [C14-3-C14im]Cl2 was selected as the emulsifier due to its excellent rheology properties. Based on the rheology results, [C14-3-C14im]Cl2 was further complexed with Brij®S10 in the decane to prepare a series of O/W emulsions through the inversed phase emulsification method. Subsequently, the stabilities of these emulsions were systemically characterized, including the droplet diameter, polydispersity index, demulsification test and long term stability. After careful evaluation of the rheology properties and the emulsion stability, the relationship between them was revealed, which was the larger the dilational modulus is, the better the emulsion stability will be. This phenomenon was further explained by the variation trend of droplet radius with time. Moreover, a thick interfacial film with large dilational modulus would lead to the decrease of the Ostwald ripening rate, coalescence rate, and creaming rate, finally resulting in the increase of the emulsion stability. These findings will further provide guidelines for the selection of surfactants and the preparation of stable emulsions.

Performance Evaluation of Fly Ash as a Potential Demulsifier for Water-in-Crude-Oil Emulsion Stabilized by Asphaltenes

Summary The quest for smart and cost–effective demulsification materials to separate water–in–crude–oil (W/O) emulsions is ongoing in the petroleum industry. We conducted an assessment study on the potency of coal fly ash (CFA) as a demulsifier for W/O emulsions. To our knowledge, this is the first study reporting CFA as a demulsifier for highly stable W/O emulsions. Samples of W/O emulsions were prepared without using any conventional emulsifier. Asphaltenes in the crude oil acted as an emulsifier, and stable emulsions were produced. Six W/O–emulsion samples of the same crude–oil/water volume ratio (4:6) were formulated. A reference sample was selected for comparison during demulsification. Demulsification tests were performed at room temperature (25°C). Demulsification results obtained using bottle tests showed that the reference sample (blank) without CFA remained stable without water separation after 48 hours, while the addition of various CFA quantities (1 to 7%) brought about the separation of water from the oil phase. Separation of water was observed to have increased with increasing CFA addition in the emulsion. Water separation continued for each sample until approximately 24 hours, when equilibrium was attained and water separation remained constant. The W/O emulsion containing 7% CFA displayed the highest performance with demulsification efficiency (DE) of 96.67%. Demulsification–comparison test results between CFA and a commercial demulsifier (poloxamer 407) using the same concentration and under room temperature showed that CFA was capable of separating water better than this commercial demulsifier. This observation indicates that CFA can compete favorably with many commercial demulsifiers available in the market. In addition, the outcome of DE of 7% CFA at elevated temperatures (i.e., 60 and 80°C) was approximately 98%. More importantly, the separated water at these elevated temperatures was clearer and contained fewer oil floccules than the separated water phase observed during demulsification tests conducted under room–temperature (25°C) conditions. Shear–rheology measurement reveals that adding CFA altered the viscoelastic characteristics at the crude–oil/water interface at an aging time of 10 hours and 55 minutes. The viscous modulus remained stagnant, whereas the elastic modulus dropped significantly. Interfacial–tension (IFT) results show that CFA particles often tend to diminish the interfacial films existing between crude oil and water. Optical morphology revealed the phase transformation in the as–prepared W/O emulsion before and after the addition of CFA particles. We propose a possible mechanism governing the demulsification of W/O emulsion driven by CFA particles. We believe that this work will be relevant to petroleum–exploration/refining operations.

Demulsification of water-in-oil emulsions using ionic liquids: Effects of counterion and water type

Demulsification of crude oil emulsions is of significant interest in the petroleum industry. This study aims to investigate the effect of ionic liquid (IL) counterions and water type (distilled water (DW) and laboratory formulated seawater (SW)) on the demulsification of water-in-oil (W/O) emulsions. Three ILs belonging to the phosphonium compounds with different counterions were used. These ILs were designated as THPC (contains chloride ion), THPD (contains decanoate ion), and THPDc (contains dicyanamide ion). Emulsions were formed using DW and SW while demulsification tests were conducted at temperatures of 60 °C and 80 °C. According to the demulsification outcomes at 60 °C, THPC was the best candidate for breaking W/O emulsions produced from DW while THPD and THPDc were excellent candidates for destabilizing emulsions produced from SW. The optimal percentage demulsification efficiency (DE) achieved for emulsions from DW was 99% with just 1000 ppm THPC while 1000 ppm THPD and 700 ppm THPDc are adequate to bring about excellent water separation in emulsions formulated from SW. THPD and THPDc also attained the maximum percentage DE of 99%.On the other hand, at elevated temperature (80 °C), THPC, THPD, and THPDc attained nearly the same water separation in the W/O emulsions produced from DW and SW with a demulsifying capacity of 99%. However, demulsification activities at this temperature (80 °C) in the W/O emulsions formed using SW were very fast as compared to what was observed in the case of emulsions obtained from DW. Thus, salts present in SW have propensities to accelerate the destabilization of crude oil emulsions. Viscosity and elastic modulus time sweep measurements reveal that the tested ILs can collapse the natural emulsifiers (asphaltenes and resins) existing at the water-oil interfaces.

Crude oil/water emulsion separation using graphene oxide and amine-modified graphene oxide particles

Graphene oxide (GO) nanosheets have been experimentally proved to be a highly efficiency, rapid and universal demulsifier to break up the crude-in-water emulsion. The alkylamine functionalization of graphene oxide is well known as a way to turn graphene oxide highly affine with organic solvents. In the present work an amphiphilic material, graphene oxide functionalized by amino groups were prepared by Hummer’s modified method. We introduced it as a versatile demulsifier to break up crude-in-water emulsions. The amphiphilic material was characterized by Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray diffraction (XRD) and emission scanning electron microscope (SEM). The efficient demulsifier to break up crude-in-water emulsion was proved in synthetic emulsion using Colombian crude oil with different concentration. Demulsification tests indicated that graphene oxide amine-modified (GO-A) could separate the crude-in-water emulsion in a short time. Demulsification performance of amphiphilic material was made using the bottle test and evaluated by UV–Vis absorption spectroscopy to measure the final grease concentration after GO-A treatment.

Demulsification of Crude Oil in Water (O/W) Emulsions using Graphene Oxide

Implementation of nanotechnology in oil and gas industries, particularly for enhanced oil recovery (EOR) has recently gained interest. In this work, graphene oxide (GO) has been synthesized and used as nano-demulsifier for crude oil in water (O/W) emulsions. GO was synthesized by using modified Hummers’ method and characterized using X-Ray diffractometer (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. Subsequently, the nano-demulsifier’s performances were tested to Field D crude oil-water emulsions by varying nano-demulsifier concentrations and contact time. The performances of GO for demulsication of crude oil-in-water emulsions were then determined by measuring the oil contents in water using a UV–Vis spectrophotometer. Demulsification tests indicated that the optimum GO concentration was around 20-40 ppm, while the optimum contact time was 30 min. The residual oil content in the separated water was as low as 100 ppm. This might be due to the amphiphilic properties of GO. It indicates that the GO is a promising demulsifier and by further understanding the intrinsic interaction between GO and crude oil, the performances of GO can be easily tailored in the future.

Investigation of the relationship between cell surface hydrophobicity and demulsifying capability of biodemulsifier-producing bacteria

Cell surface hydrophobicity (CSH) is one of the key physicochemical features of biodemulsifier-producing bacteria that influence their demulsification capability maintenance in petroleum contaminated environments. In present study, biodemulsifier-producing bacteria were isolated from petroleum contaminated environments using different isolation media and the correlation between their CSH and demulsifying ability was investigated. The demulsifying ability of isolates was measured through demulsification tests on water in kerosene emulsions. The microbial adhesion to the hydrocarbon (MATH) assay was used to denote their CSH. The evaluation of CSH showed that majority of biodemulsifier producing bacteria have high CSH which indicating a positive correlation between CSH and demulsifying capability. According to these results it can be concluded that CSH can be used as an indicator for assessment of biodemulsifier-producing bacteria and screening of new isolates for their biodemulsifier production.