Demulsification Of Crude Oil Emulsions Research Articles

Cucurbit[7]uril-Modified Nano SiO2 for Efficient Separation of Crude Oil Emulsions: Properties and Demulsification Mechanism.

Demulsification of crude oil emulsion is an obvious problem in the whole of petroleum engineering, which needs to be dealt with urgently. In this paper, a supramolecular material Cucurbit[7]uril-SiO2 (CB-SiO2) synthesized with excellent demulsification efficiency (DE) on O/W emulsion was synthesized by a simple thermal synthesis method. The microscopic morphology and structure were investigated through modern characterization techniques. Furthermore, its stability, dynamic interfacial tension (IFT), and wettability (three-phase contact angle (CA)) were systematically investigated, and the demulsification efficiency of different conditions on crude oil emulsion was also investigated. Reassuringly, these results showed that when the temperature was 70 °C, the demulsification dosage was close to 600 mg/L and remained unchanged for 90 min; the demulsification efficiency is 2.2 times compared with the unmodified material, up to 93.63%. In addition, a plausible demulsification mechanism was proposed, which is that CB-SiO2 can adsorb and disrupt the oil-water interface, leading to oil-water separation and promoting demulsification. It is a promising demulsification material for the oil industry demulsification.

Demulsification of crude oil emulsions using a three-branched betaine type ionic liquid and its demulsification mechanism

In this work, a three-branched betaine type ionic liquid (TESA) with elevated interfacial activity was synthesized to separate water from crude oil emulsions at low temperature. The chemical structure, demulsification performance, and demulsification mechanism of TESA was investigated. The bottle tests exhibited that the dehydration efficiency was 100% with 150 mg/L of TESA for 40 min at 50 °C. TESA was effective in acidic, alkaline, and high salinity conditions. The dehydration efficiency of TESA was more than 95.63% with a wide pH range of 3–11. Furthermore, the dehydration efficiency was 100% with 50000 mg/L of salinity for 20 min at 50 °C. Encouragingly, the dehydration efficiency of TESA was better than that of commercial demulsifiers and reported work. The excellent dehydration efficiency of TESA was ascribed to the elevated interfacial activity, amphipathy, and strong interaction with asphaltenes. As a result, TESA improved the substitution of asphaltenes and considerably reduced interfacial tension, resulting in an unstable interfacial film and leading to demulsification. It indicated that TESA was an effective demulsifier, which promised application in the oil industry.

Demulsification of Crude Oil Emulsions Using Versatile and Eco-Friendly Demulsifiers Based on Cellulose Decorated with Imidazolium-Bearing Triazole Moiety.

Water in the crude oil forms emulsions that must be broken before refining processes. Here, the novel and versatile derivatives of imidazolium ionic liquids (ILs) containing triazole moiety [SIm-TazCn][Br] were synthesized via click chemistry and then grafted onto the cellulose (CEL) to prepare eco-friendly demulsifiers for breaking water-in-oil (W/O) emulsions. The prepared compounds with two kinds of alkyl chains named CEL[SIm-TazC6][Br] and CEL[SIm-TazC10][Br] were characterized and employed for demulsifying W/O (30:70 and 50:50 vol %) emulsions. Also, the effect of the type and concentration of each demulsifier on the phase separation and dehydration efficiency (DE) were investigated through the bottle test. According to the bottle test results, the CEL[SIm-TazC6][Br] derivative at 4000 ppm showed a good DE of 79% after 5 min, which increased to 82% after 24 h. The interfacial tension (IFT) of derivatives at different concentrations was measured. The minimum IFT value of 16.3 mN/m was obtained for CEL[SIm-TazC6][Br] with a shorter alkyl chain at 4000 ppm after 24 h. The green and efficient CEL-based surfactants significantly demulsified the W/O emulsions because of the collaboration between imidazolium and triazole moieties.

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.

Preparation of an environmentally friendly demulsifier using waste rice husk as raw materials for oil–water emulsion separation

Demulsification of crude oil emulsions still face many difficulties in the petroleum industry. Therefore, it is very important to develop innovative materials to achieve the effective separation of oil–water emulsions. In this work, an environmentally friendly RHC-0.5 demulsifier was prepared via a simple one-step hydrothermal route using rice husk (RH) as raw materials. It was characterized by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, energy dispersive X-ray spectrometer and thermogravimetric analysis. The possible breaking mechanism was analyzed by particle size analysis, Zeta potential, interfacial activity, interfacial tension, self-assemble of interfacial film and microscopic analysis. The influence of some important factors such as dosage, temperature, standing time and salinity on the demulsifying efficiency (DP) was explored through bottle tests. The optimal DP of 95.01 % could be obtain with 300 mg/L of RHC-0.5 at 70 °C for 10 min. Meanwhile, RHC-0.5 had a good salt tolerance even at the salinity of 40000 mg /L. In addition, its DP was compared with that of commercial demulsifiers such as SP169, CH-66 and AR-32. This work not only can promote the efficient utilization of biological waste (RH), but also provides an insight into the exploration of new demulsifying materials with excellent performance.

Numerical assessment of ultrasound supported coalescence of water droplets in crude oil

In this study, a numerical assessment of the coalescence of binary water droplets in water-in-oil emulsion was conducted. The investigation addressed the effect of various parameters on the acoustic pressure and coalescence time of water droplets in oil phase. These include transducer material, initial droplet diameter (0.05–0.2 in), interfacial tension (0.012–0.082 N/m), dynamic viscosity (10.6–530 mPas), temperature (20–100 °C), US (ultra sound) frequency (26.04–43.53 kHz) and transducer power (2.5–40 W). The materials assessed are lead zirconate titanate (PZT), lithium niobate (LiNbO3), zinc oxide (ZnO), aluminum nitride (AlN), polyvinylidene fluoride (PVDF), and barium titanate (BaTiO3). The numerical simulation of the binary droplet coalescence showed good agreement with experimental data in the literature. The US implementation at a fixed frequency produced enhanced coalescence (t = 5.9–8.5 ms) as compared to gravitational settling (t = 9.8 ms). At different ultrasound (US) frequencies and transducer materials, variation in the acoustic pressure distribution was observed. Possible attenuation of the US waves, and the subsequent inhibitive coalescence effect under various US frequencies and viscosities, were discussed. Moreover, the results showed that the coalescence time reduced across the range of interfacial tensions which was considered. This reduction can be attributed to the fact that lower interfacial tension produces emulsions which are relatively more stable. Hence, at lower interface tension between the water and crude oil, there was more resistance to the coalescence of the water droplets due to their improved emulsion stability. The increment of the Weber number at higher droplet sizes leads to a delay in the recovery of the droplet to spherical forms after their starting deformation. These findings provide significant insights that could aid further developments in demulsification of crude oil emulsions under varying US and emulsion properties.

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.

The demulsification of crude oil emulsion driven by a natural lotus leaf grafted with nano-SiO2

An environmentally friendly LLP@SiO2 demulsifier was prepared by coating nano-SiO2 on the natural lotus leaf powder (LLP) via a simple hydrothermal method. Fourier-transform infrared spectroscope (FT-IR), field-emission scanning electron microscope (FE-SEM), energy dispersive X-ray spectroscope (EDS) and thermal gravimetric analyzer (TGA) were employed to characterize the demulsifier. The effect of the LLP@SiO2 dosage, temperature, settling time, pH value and salt concentration on the demulsifying process was studied in detail. The bottle test results showed that the demulsification efficiency (DE) reached 83.78% within 1 min when the dosage was 600 mg/L at 70 °C. The DE could increase to 91.91% if the settling time was prolonged to 60 min. The LLP@SiO2 demulsifier had excellent acid and salt tolerance, and the high salinity also could improve the demulsification performance. It showed that the DE could maintain at 91.91% even at strong acid condition of pH = 2 and it increased to 94.33% when the salinity was increased to 20,000 mg/L. In addition, the possible demulsification mechanism was systematically studied by the interfacial activity, interfacial tension (IFT), wettability and microexamination.

Demulsification of crude oil emulsion using carbonized cotton/silica composites

As a substitute for conventional oilfield chemicals, biomass-based composite materials have received extensive attention. In this study, degreasing cotton (DC) and tetraethyl orthosilicate (TEOS) were used as raw materials to synthesize carbonized cotton coated with SiO2 (CC@SiO2). CC@SiO2 was characterized by Fourier-transform infrared spectroscopy (FT-IR), X-ray spectroscopy (XRD), field-emission scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometer (EDS). The effect of vital factors such as CC@SiO2 dosage, settling time and temperature on the demulsification performance was investigated. The optimal demulsification efficiency (DE) could reach 90.38% after demulsifying with 400 mg/L of CC@SiO2 at 65 ℃ for 120 min. The demulsification mechanism was studied by investigating the dynamic interfacial tension (IFT), interfacial activity and wettability. Additionally, the flocculation and aggregation of water droplets and separation of oil-water in emulsion were observed by the optical microscope. The current work indicates that CC@SiO2 is a simple, high-efficient demulsifier for the separation of the water-containing crude oil, which shows a good application prospect in oil industry.

An overview of recent technique and the affecting parameters in the demulsification of crude oil emulsions

The crude oil mix with water through processing and under significant shear at the wellhead and with the assistance of surface-active substance which is present naturally in the crude oil leading to the formation of water-oil emulsions. These emulsions are undesirable and cause problem like pipeline corrosion, pump malfunctions, poisoning of downstream refinery catalysts, and other problems. Emulsions are needed to demulsify and separate the water. There are various parameters related in crude oil demulsification that can both reduce or rise the stability of the emulsion by altering each. Therefore, this study presents an overview of research efforts on the state-of-the-art demulsification techniques through the last years and the parameters affecting the demulsification process. Firstly, an overview of the crude oil emulsion, kinds, formation, and stability. After that, a short discussion of the different demulsification techniques process. Finally, the study of the parameters affecting the demulsification process, including salinity, temperature, pH, water content, and emulsifier/demulsifier dose. The review of literature culminated in the proposition for future research.

Charge-Transfer-Induced Noncoalescence and Chain Formation of Free Droplets under a Pulsed DC Electric Field.

Electrocoalescence technology is an important method for the demulsification of crude oil emulsion, but its development is restricted by the short circuit caused by droplet chain formation. To reveal the formation mechanism of droplet chains, the electrocoalescence behaviors of two droplets and droplet clusters under pulsed direct current (DC) electric fields are experimentally studied. The two droplets usually successively undergo complete coalescence, partial coalescence, and noncoalescence as the electric field strength increases. The critical electric field strengths for complete coalescence under pulsed DC electric fields with different frequencies are obtained. The effects of the electric field waveform and frequency on the noncoalescence characteristics of two droplets and the stability of droplet chains are explored. The droplet chains under a high-frequency electric field are more stable and longer than those under a low-frequency electric field due to the reduction of the movement distance and the generation of daughter droplets from tip streaming. The reversal of the composition of electric forces due to charge transfer is the fundamental mechanism of noncoalescence of two droplets and chain formation in the emulsion under a pulsed DC electric field.

Evaluation of a naturally derived waste brown oil extract for demulsification of crude oil emulsion

Conventional methods of eliminating water from crude oil such as the chemical injection have both economic and environmental impacts; thus, this study proposed an economic and environmentally friendly demulsifier. The bottle test method was used to study the performance of the natural extract and commercial demulsifier on a crude oil sample. The GC-MS profile of the extract was in agreement with previous reports on composition of oil extracted from rice bran using hexane, ultrasound assisted extraction and conventional solvent extraction with ethanol. Varying degrees of saturated and unsaturated fatty acids as well as retention times as observed, was a function of total time of scanning, according to NIST08 library of mass spectra. The performance of the demulsifier was expressed in terms of percentage of water separated from 100 ml samples of the oil samples. For both the demulsifiers, the performance increased with increase in volume of the demulsifier, separation time and operating temperature. The extracted demulsifier performed better than the chemical demulsifier under all the experimental conditions adopted in this study. Based on the parametric evaluation, it was observed the results from software corroborated the results obtained from experiments in terms of the observations of the combined effect of temperature and volume which showed the most significant influence on demulsification of the emulsified crude. The highest efficiency of the bio-demulsifier was obtained with a volume of 5 mL of the extract, at a temperature of 70°C and separation time of 60 min. A water separation efficiency of 85.6% was obtained as compared to the chemical demulsifier, which gave an efficiency of 80.2%.

Demulsification of Crude Oil Emulsion in Well X in a Niger Delta Field

Crude oil emulsion is an inevitable phenomenon in hydrocarbon production. Treatment of crude oil emulsion is challenging when the emulsion is stabilized. As crude oil is brought to the surface and pumped to the production facilities, the formation of emulsion increases operating cost. There is a wide array of demulsifiers that are available in the oil and gas industry for the treatment of crude oil emulsion, but one major concern has always been the efficiency of the treatment. No single universal demulsifier can effectively remove emulsion and a combination of two or more is usually expensive. In this study, crude samples were collected from the inlet manifold of a Niger Delta field and bottle tests were conducted with several demulsifiers to select the best chemical demulsifier for use in treating the emulsions as well as the optimum combination. To achieve this objective, twelve different industrial-based demulsifiers were considered which were EXP50, Separol NF-36, Baker-Basf V13-312, Servo CC-8271, Tretolite RP6275, NACCO-Exxon 006-1442, DMO87005, EXP30, AnticorQIT007, AnticorBE027, DMO86634 and DMO81656. It was observed that DMO87005 and AnticorQIT007 produced better results based on separated water volume than other demulsifiers. Hence, the decision to use these demulsifiers to assess their combined potential and the demulsifier factors, namely, concentration, temperature and time effects on the separated water volume using design of experiments (DOE) approach. The results obtained shows that the selected demulsifiers DMO87005 and AnticorQIT007 in a combined form separate more water volume from the crude oil emulsion. Also, the performance of the combined demulsifier is dependent on the combination ratio of the selected demulsifiers. Furthermore, the results depict that the selected (non-combined) demulsifiers and the combined demulsifier factors’ main effects on the separated water volume are concentration, while concentration-time and temperature-time are the factors’ interaction effects for selected and combined demulsifiers, respectively. Again, the magnitude of the main and interaction effects of the combined demulsifier’s factors on the separated water volume is affected by the selected demulsifiers combination ratio. Thus, the combined demulsifier at 0.45mL concentration at a temperature of 90°C for 60 minutes gave a good potential that would necessitate its use for crude oil emulsion treatment in the Niger Delta.

Demulsification of crude oil emulsions tracked by pulsed field gradient NMR. Part II: Influence of chemical demulsifiers in external AC electric field

Crude oil emulsions can reach stability levels that pose severe challenges for the processing industry. Certain conventional methods are used to deal with these challenges, such as chemical demulsification. In this article, two chemicals were mixed with crude oil emulsions to study their separation capabilities in the presence and absence of external AC fields. Experiments were conducted at 65 ⁰C to lower crude oil viscosity, which in turn affects separation efficiency. Effects from the chemical and electrical constituents on the crude oil emulsion was tracked by a pulsed field gradient NMR method, developed in a previous study. The NMR measured emulsified water content for 2 h, continuously, as a function of sample height. Given the water content, droplet sedimentation and free water layer kinetics could be quantified. Droplet size distributions from the top half oil phase were obtained at the beginning and end of each experiment, with the intent of mapping coalescence and sedimentation development of droplets. However, tracking droplet size evolution proved challenging due to rapid changes within the emulsion. The main focus with the NMR technique was therefore on sedimentation and free water layer kinetics. A synergy was observed between the two chemicals and low AC fields. The two chemicals showed varied degrees of separation efficiency, where limited amounts of water was resolved by chemical 1 without electric field, though it improved separation past the limit of electrical treatment when used in combination with AC field. Above a given electric field, sedimentation by electrocoalscence dominates, and the effect of chemical demulsifier is marginal. Chemical 2 achieved promising results as a lone separation method, while further enhancing separation in collaboration with AC fields.

An Overview of Recent Advances in State-of-the-Art Techniques in the Demulsification of Crude Oil Emulsions

The processing of crude oil often requires the extraction of a large amount of water. Frequently, crude oil is mixed with water to form water-in-crude oil emulsions as the result of factors such as high shear at the production wellhead and surface-active substances that are naturally present in crude oil. These emulsions are undesirable and require demulsification to remove the dispersed water and associated inorganic salts in order to meet production and transportation specifications. Additionally, the demulsification of these crude oil emulsions mitigates corrosion and catalyst poisoning and invariably maximizes the overall profitability of crude oil production. Recently, there has been growing research interest in developing workable solutions to the difficulties associated with transporting and refining crude oil emulsions and the restrictions on produced water discharge. Therefore, this paper reviews the recent research efforts on state-of-the-art demulsification techniques. First, an overview of crude oil emulsion types, formation, and stability is presented. Then, the parameters and mechanisms of emulsification formation and different demulsification techniques are extensively examined. It is worth noting that the efficiency of each of these techniques is dependent on the operating parameters and their interplay. Moreover, a more effective demulsification process could be attained by leveraging synergistic effects by combining one or more of these techniques. Finally, this literature review then culminates with propositions for future research. Therefore, the findings of this study can help for a better understanding of the formation and mechanisms of the various demulsification methods of crude oil to work on the development of green demulsifiers by different sources.

Application of Microwave Heating in the Demulsification of Crude Oil Emulsions

Application of Microwave Heating in the Demulsification of Crude Oil Emulsions

An evaluation of lignocellulosic solutions from OPEFB pulping process as demulsifiers for crude oil emulsion demulsification

Lignocellulosic solutions from oil palm empty fruit bunch (OPEFB) organosolv pulping process are used as demulsifiers for demulsification of crude oil emulsion using a model of water-in-oil emulsion of crude oil and brine solution. The results indicate that the demulsification performance was favored when only lignin compound was contained in the demulsifier. The phase separation capacity and rate were strongly affected by brine pH values, temperatures and demulsifier dosages. Complete phase separation capacity was achieved at the optimum conditions. The separated oil and water are qualified for refining process and water treatment, respectively, making it promising as a demulsifier.

Demulsification of crude oil emulsion by capacitative sensor system measurement: introduction to apparatus and methodology

Standard Bottle Test is often the most common technique to gauge the demulsification performance of a newly formulated crude oil demulsifier. In our work, we have attempted to devise a more specific reliable and reproducible technique for monitoring the demulsification process. It is well-known that as water separates from a crude oil emulsion the capacitance of the mixture changes. By monitoring the change in capacitance at different heights of the emulsion with respect to time using in-house developed capacitance probe, we accurately measure the separation rate and the efficiency of the demulsifier. It was found that substantial changes in the capacitance occurred as the water separates from the emulsion. This method not only has the advantage of being more accurate and robust but can also be adapted to be used directly in the oil field. Here we have used our previously synthesized surfactant Lauramidopropyl glyceryl dimethyl ammonium chloride (LGDMAC) as a demulsifier and its performance has been compared to that of Benzalkonium Chloride. The separation rate and the efficiency were found to be the highest for LGDMAC. Data obtained by the capacitance measurements enabled the determination of the kinetics of the separation rate as well as to quantify the separated water.

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.

Demulsification of Crude Oil Emulsions Tracked by Pulsed Field Gradient (PFG) Nuclear Magnetic Resonance (NMR). Part I: Chemical Demulsification

Emulsified water droplets must be extracted from crude oil for economical and transport purposes, which is achievable by chemical demulsification. Four different chemicals were tested on water-in-crude oil emulsions using a newly developed nuclear magnetic resonance (NMR) method. Droplet size distributions were mapped at the beginning and end of experimentation. In addition, slice selections (soft radio-frequency (RF) pulses) were used to isolate the signal from residual droplets within the separated oil phase to study coalescence patterns in the emulsion bulk. The NMR could also return rapid continuous brine profiles for analysis of sedimentation rates and free water appearance kinetics. The residual water content was isolated by strong bipolar gradient suppression, thereby allowing focus on the smaller droplets still emulsified in the top region in the brine profiles. Optimum concentrations were found for each chemical, and blends of several chemical demulsifiers were noticeably more efficient than the ...