Research on the static experiment of super heavy crude oil demulsification and dehydration using ultrasonic wave and audible sound wave at high temperatures

Mechanism study of aging oil demulsification and dehydration under ultrasonic irradiation

With the tertiary oil recovery in the oilfield, the content of aging oil emulsion with high water content and complex components has become more prevalent, so it is crucial for aging oil to break the emulsification. In this paper, the experimental laws of water content are explored under the conditions of different transducer input powers through the ultrasonic reforming of aging oil, and the microscopic topography, particle size, components, etc. of oil samples before and after the irradiation of ultrasound are characterized through the microscopic analysis, particle size analysis and component analysis and other ways. The results show that the oil samples achieve the effect of demulsification and dehydration in the presence of ultrasonic cavitation effect, with a maximum dehydration rate of 98.24 %, and that the dehydration rate follows an "M-type" trend with the increase of power. The results of microscopic and particle size analyses demonstrate that ultrasonic irradiation destabilizes the oil-water interfacial membrane, and causes droplets of different sizes to collide, agglomerate, and settle. It was also observed that the droplets of the emulsion system are more evenly distributed and the intervals are increased. Furthermore, we hypothesize that ultrasound may be less irreversible in demulsification and dehydration of aging oil.

Synthesis of nano-β-CD@Fe3O4 magnetic material and its application in ultrasonic treatment of oily sludge

The extraction process of Tarim oil field in Xinjiang is accompanied by a large amount of oily sludge generation, which seriously restricts the progress of oil and gas development and causes serious pollution to the environment due to its large production, complex composition, and difficult treatment. Nanomaterials combined with ultrasound have been demonstrated to be a promising method for the disposal of hazardous oily sludge. In this paper, a magnetic material Nano-β-CD@Fe₃O₄ was prepared by hydrothermal method and surface modification method. Nano-β-CD@Fe₃O₄ can be intelligently enriched at the oil-water interface and oil-solid interface, and it can be stably dispersed to form nanofluid under the action of ultrasound. Nano-β-CD@Fe₃O₄ can cause changes in oil composition when it is exposed to ultrasound, resulting in the decrease of viscosity and increase of fluidity. The experimental results of treating oily sludge in Xinjiang Tarim showed that the best treatment effect was achieved when the concentration of Nano-β-CD@Fe₃O₄ was 0.5 %, the ultrasonic frequency was 60 Hz and the temperature was 60℃. This solution can reach 90.17 % oil removal efficiency within 45 min, and the secondary oil removal efficiency of Nano-β-CD@Fe₃O₄ recovered by magnetic separation could still reach 85.65 %. This efficient oily sludge treatment method proposed in our study provides valuable information for the development of oily sludge treatment technology.

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.

Recent Progress toward Physical Stimuli-Responsive Emulsions

Emulsion as a fine dispersion of immiscible liquids has involved widespread applications in industry, pharmaceuticals, agriculture and personal care. Stimuli-responsive emulsions capable of on-demand demulsification or changing their properties are required in many cases such as controllable release cargo, oil recovery, emulsifiers recycle and product separation, great progress has been achieved in these areas. Among these various triggers, much effort has been made to develop physical stimuli, due to the noninvasive and environmentally friendly characteristics. Physical stimuli-responsive emulsions provide a plenty of valuable practical applications in the fields of sustainable industry, biomedical reaction, drug delivery. Here, we summarize the recent development in the field of emulsions in response to physical stimuli consisting of temperature, light, magnetic field, electrical field, etc. The preparation methods and mechanisms of physical stimuli-responsive emulsions and their applications of catalysis reaction, drug delivery, and oil recovery are highlighted in this review. The future directions and outstanding problems of the physical stimuli-responsive emulsions are also discussed. This article is protected by copyright. All rights reserved.

Demulsification of Heavy Oil-in-Water Emulsion by a Novel Janus Graphene Oxide Nanosheet: Experiments and Molecular Dynamic Simulations

Various nanoparticles have been applied as chemical demulsifiers to separate the crude-oil-in-water emulsion in the petroleum industry, including graphene oxide (GO). In this study, the Janus amphiphilic graphene oxide (JGO) was prepared by asymmetrical chemical modification on one side of the GO surface with n-octylamine. The JGO structure was verified by Fourier-transform infrared spectra (FTIR), transmission electron microscopy (TEM), and contact angle measurements. Compared with GO, JGO showed a superior ability to break the heavy oil-in-water emulsion with a demulsification efficiency reaching up to 98.25% at the optimal concentration (40 mg/L). The effects of pH and temperature on the JGO’s demulsification efficiency were also investigated. Based on the results of interfacial dilatational rheology measurement and molecular dynamic simulation, it was speculated that the intensive interaction between JGO and asphaltenes should be responsible for the excellent demulsification performance of JGO. This work not only provided a potential high-performance demulsifier for the separation of crude-oil-in-water emulsion, but also proposed novel insights to the mechanism of GO-based demulsifiers.

Ultrasound-assisted desalination of crude oil: The influence of mixing extent, crude oil species, chemical demulsifier and operation variables

Coalescence of water droplets in crude oil has been effectively promoted by chemical demulsifiers integrated with ultrasound. Temporary images of water droplets in W/O emulsions were directly monitored using a metallurgical microscope. Water droplets achieved expansion of 118% at 40 min ultrasonic irradiation time under well mixing conditions. However, water droplets in heavy crude oil undergo less aggregation than those in light crude oil, due to resistance of mobility in highly viscous fluid. In the absence of chemical demulsifiers, water droplets enveloped by native surfactants appeared to aggregate arduously because of occurrence of interfacial tension gradients. Influential significance analyses have been executed by a factorial design method on operation variables, including acoustic power intensity, operation temperature, ultrasonic irradiation time and chemical demulsifier dosages. In this work, the outcomes indicate that the optimal operating conditions for desalination of crude oil assisted by ultrasound were as follows: acoustic power intensity = 300 W, operation temperature = 90℃, ultrasonic irradiation time = 75 min and chemical demulsifier dosages = 54 mg/L. Besides, it was found that the most influential importance of operation parameter was temperature, followed with acoustic power intensity, ultrasonic irradiation time and chemical demulsifier dosages.

Recent developments, challenges, and prospects of ultrasound-assisted oil technologies

There has been consistent drive towards research and innovation in oil production technologies in order to achieve improved effectiveness and efficiency in their operation. This drive has resulted in breakthrough in technologies such as the application of ultrasound (US) in demulsification and enhanced oil recovery (EOR), and usage of high-volume hydraulic fracturing and special horizontal well for shale oil and gas extraction. These can be observed in the increment in the number of commercial oil technologies such as EOR projects that rose from 237 in 1996 to 375 in 2017. This sustained expansion in EOR resulted in their total oil production rising from 1.5 million barrels per day in 2005 to 2.3 million barrels per day in 2020. And this is predicted to increase to about 4.7 million barrels per day in 2040, which represent about 4% of total production. Consequently, in this review, the developments in the utilization of US either as standalone or integrated with other technologies in EOR and dehydration of water in oil emulsions were analyzed. The studies include the optimization of fluid and US properties in EOR and demulsification. Reports on the treatment of formation damage resulting from inorganic salts, organic scales, drilling fluid plugs, condensate, paraffin wax and colloidal particle with US-assisted EOR were also highlighted. Moreover, the mechanisms were examined in order to gain insightful understanding and to aid research investigations in these areas. Technologies such as US assisted green demulsification, high intensity focused ultrasound, and potential pathways in field studies were assessed for their feasibilities. It is essential to evaluate these technologies due to the significant accrued benefits in them. The usage of green demulsifiers such as deep eutectic solvents, ionic liquids and bio-demulsifiers has promising future outlook and US could enhance their technical advancement. HiFU has been applied successfully in clinical research and developments in this area can potentiality improve demulsification and interfacial studies (fluid-fluid and solid-fluid interactions). As regards field studies, there is need to increase actual well investigations because present reports have few on-site measurements with most studies being in laboratory scale. Furthermore, there is need for more detailed modeling of these technologies as it would assist in conserving resources, saving research time and fast-tracking oil production. Additional evaluative studies of conditions such as the usage of Raschig rings, crude oil salinity and high temperature which have improved demulsification of crude oil emulsions should be pursued.

Treatment of oil-based drilling cuttings using the demulsification separation-Fenton oxidation method

In this study, demulsification separation-Fenton oxidation technology was employed as a combined technology to treat total petroleum hydrocarbons (TPH) in oil-based drill cuttings (OBDC). Batch experiments were carried out to optimize the technology parameter. Under the optimal condition, 70% and 51% TPH removal rate was obtained for demulsification technology and Fenton oxidation technology, respectively. Eighty-five percent of TPH removal rate was obtained using combination technology of demulsification separation and Fenton oxidation. Multiple characterizations were used to analyze the physical and chemical properties of treated OBDC. The result of XRD pattern indicated the combination technology had no obvious effect for structure phase of OBDC. The results of FTIR, GC-MS, TG-DTG and SEM were used to characterize the treated OBDC. This paper provides an efficient and feasible combined technology for OBDC treatment, which expands a new strategy for the removal of TPH from solid waste.

Peculiarities of Dewatering Technology for Heavy High-Viscosity Crude Oils of Eastern Region of Ukraine

High-viscosity crude oils from the Yablunivske field (Ukraine, Poltava region) have been studied. The oils were diluted with gas condensate to reduce viscosity, and then various demulsifiers were added. It was established that it is expedient to dilute oil with heavy gas condensate and dehydrate it with PM-1441 brand A non-ionogenic demulsifier, based on block copolymers of ethylene and propylene oxides. The dewatering degree was found to be 95 %.

Recent advances in applications of power ultrasound for petroleum industry

Power ultrasound, as an emerging green technology has received increasing attention of the petroleum industry. The physical and chemical effects of the periodic oscillation and implosion of acoustic cavitation bubbles can be employed to perform a variety of functions. Herein, the mechanisms and effects of acoustic cavitation are presented. In addition, the applications of power ultrasound in the petroleum industry are discussed in detail, including enhanced oil recovery, oil sand extraction, demulsification, viscosity reduction, oily wastewater treatment and oily sludge treatment. From the perspective of industrial background, key issue and resolution mechanism, current applications and future development of power ultrasound are discussed. In addition, the effects of acoustic parameters on treatment efficiency, such as frequency, acoustic intensity and treatment time are analyzed. Finally, the challenges and outlook for industrial application of power ultrasound are discussed.

Study on the effect of oxidation-ultrasound treatment on the electrochemical properties of activated carbon materials

Activated carbon (AC) has been widely used in water treatment because of its rich pore structure, large specific surface area, simple production process, low preparation cost and wide source of raw materials. In this paper, the regeneration efficiency of low-frequency ultrasonic pretreatment (40 kHz, 115Μw/cm³) on biological activated carbon (BAC) is investigated, and its principle is discussed. The results show that the micro-jet and micro-liquid flow with high temperature and pressure produced by micro-bubble rupture during ultrasonic cavitation play an important role in the regeneration of activated carbon. And optimum ultrasonic treatment time is determined (5 min). In addition, the preparation of cu-loaded activated carbon by ultrasound-microwave method is investigated to pretreat wastewater produced in paracetamol production. The results show that Cu and Cu oxides can be loaded on activated carbon surface by ultrasonic-microwave pretreatment. Finally, the pretreatments of activated carbon by physical, chemical and physical-chemical method are investigated. The effects of the above different pretreatment methods on the structure and adsorption properties of activated carbon are compared and evaluated.

Removal of colloidal precipitation plugging with high-power ultrasound

Petroleum is a continuous and dynamically stable colloidal system. In the process of oil extraction, transportation, and post-treatment, the stability of the petroleum sol system is easily destroyed, resulting in asphaltenes precipitation that can make pore throat, oil wells, and pipelines blocked, thereby damaging the reservoir and reducing oil recovery. In this paper, removing near-well plugging caused by asphaltene deposition with high-power ultrasound is investigated. Six PZT transducers with different parameters were used to carry out the experimental study. Results show that ultrasonic frequency is one important factor for removing colloidal precipitation plugging in cores, it could not be too high nor too low. The optimum ultrasonic frequency is 25 kHz; Selecting transducers with a higher power is an effective way to improve the removal efficiency. The optimum ultrasonic power is 1000 W. With the increase of ultrasonic treatment time, the recovery rate reaches the maximum and tends to be stable. ultrasonic processing time should be controlled within 120 min. Besides, three methods - ultrasonic treatment alone, chemical injection alone, and ultrasound-chemical method - for removing colloidal precipitation plugging are compared. Results indicate that the ultrasound-assisted chemical method is better than chemical injection alone or ultrasonic treatment alone to remove colloidal sediment in the core. Finally, the mechanism of the ultrasonic deplugging technique is analyzed from three aspects: cavitation effect, the thermal effect, and mechanical vibration.

Ultrasound-assisted electrochemical treatment for phenolic wastewater

With the rapid development of industry, especially the rapid rise of the chemical industry, the problem of water pollution is becoming more and more serious. Among them, the discharge of organic pollutants represented by phenolic substances has always been at the forefront. In this paper, ultrasound-assisted electrochemical treatment for phenolic wastewater is investigated. The effects of ultrasonic frequency, current, pH value and the amount of fly ash-loaded titanium TiO₂-Fe³⁺ particles on phenol removal from phenol-containing wastewater are investigated. The experimental results demonstrate that the removal rate of phenol in phenol-containing wastewater is the best when ultrasonic frequency is 45 kHz, power is 200 W, the current is 1.2 A, pH is 5 and the dosage of fly ash-loaded titanium TiO₂-Fe³⁺ particles is 3 g. In addition, microwave-assisted-Fenton reagent treatment for phenol wastewater is investigated. The effects of Fenton reagent dosage, initial pH value, microwave power density and radiation time on phenol degradation rate are investigated. The results show that microwave can accelerate the reaction rate, reduce the number of metal ions, save the process cost and reduce the difficulty of post-treatment. Finally, the research status of phenol wastewater treatment technology at the present stage is reviewed, and the future development direction is discussed.

Research on the removal of near-well blockage caused by asphaltene deposition using sonochemical method

Near-well blockage caused by asphaltene deposition often occurs during the process of crude oil exploitation. It can reduce the porosity and permeability of reservoirs and seriously affects the migration and exploitation of oil and gas. In this paper, removing near-well blockage caused by asphaltene deposition using sonochemical method is investigated. Six PTZ transducers with different parameters are used to study the deplugging effect. Results show that the optimal ultrasonic frequency and power for plugging removal are 20 kHz and 1000 W respectively. it is found that lower ultrasonic frequency is good for asphaltene deposition plug removal when ultrasonic power is constant; as the power of the sensor increases, the effect of removing the asphaltene deposition plug gets better, ultrasonic power can well make up for the attenuation of ultrasonic energy caused as frequency increases; the effects of removing asphaltene deposition plug for the three cores with different initial gas logging permeability all get worse no matter what type of transducer is used; the effect of asphaltene deposition plug removal for the three cores samples all become better and then tend to be stable as ultrasonic treatment time increases further; considering of reducing construction cost and oil reservoir protection, ultrasonic processing has a lot of unexampled advantages compared with chemical injection, such as good adaptability, low cost, simple operation, non-pollution and benefit for the sustainable development of oil field; affected by the synergistic effect of ultrasonic and chemical agents, the combined treatment effect of ultrasound and chemical agents is significantly better than using ultrasound or chemical agents alone.

Study on ultrasonic-electrochemical treatment for difficult-to-settle slime water

The treatment of slime water not only has a direct impact on the economic benefits of the coal preparation plant, but also has an important significance for the conservation and utilization of the environment and water resources in the mining area. However, under the background of increasing mechanization level of coal mining, the proportion of fine coal is increasing, and the slime water exhibits fine, high and sticky characteristics in terms of particle size, ash, and viscosity, making it difficult for the slime water to settle. In this paper, research on the treatment of difficult-to-settle slime water by ultrasound-electrochemistry is investigated. The principle of the ultrasonic-electrochemical method for treating difficult-to-settle slime water is discussed. The effects of electrodes, electrolytes, ultrasonic energy density and ultrasonic time on treatment of difficult-to-settle slime water are analyzed. Results show that ultrasound-electrochemical pretreatment for difficult-to-settle slime water is not a simple superposition of the two treatment methods, and ultrasound can promote the electrochemical reaction. The optimal ultrasonic parameters are given: ultrasonic frequency, energy density and ultrasonic time are 29 kHz, 0.5 W/m³ and 4 min respectively. Based on the basic properties of the micro-charge on the surface of coal particles, the flocculation sedimentation can be promoted effectively by the combination of sonochemical and electrochemical methods. Finally, the research status of the new treatment technology for difficult-to-settle slime water is discussed, and the development trend is pointed out.

Study on ultrasonic treatment for degradation of Microcystins (MCs)

In recent years, The ecological environment of rivers and lakes have been seriously polluted, and the eutrophication of water bodies has become increasingly prominent, which not only seriously affects the living environment of surrounding residents, but also poses a major threat to the ecological security of water environment. The growth of algae is characterized by short cycle, rapid reproduction and great harmfulness. Conventional algal removal technology is expensive, easy to produce secondary pollution, and difficult to effectively inhibit algae outbreaks, therefore, a new environmental protection technology, ultrasonic algae removal technology, has been put forward. Under the background of ecological environment pollution, in this paper, the effect of ultrasonic technology on degradation of Microcystins (MCs) under different conditions and is investigated. Results show that Microcystins removal rate reaches 81% when Microcystin solution with a concentration of 12.43 mu/L is treated by ultrasound (1200 W) for 5 min; the removal rate of Microcystin reaches 99% after 15 min of ultrasound treatment (1200 W), and almost all of them are removed; no matter wastewater containing Microcystis is treated by ultrasound alone or ultrasound-coagulation method, the levels of Microcystins in the water do not increase. The results also prove that ultrasound can directly destroy the wall and kill algae, inhibit the growth activity of un-killed algae and degrade Microcystins. In addition, the technical principle and application prospect of ultrasonic algae removal instrument in ecological environment are introduced. The paper provided certain direction and theoretical support for the subsequent improvement of ultrasonic algae removal technology.

Advances in ultrasonic production units for enhanced oil recovery in China

With the development of oil recovery technology, ultrasonic technology has been involved in oil production and oilfield development. The mechanism of ultrasonic wave plugging in near well is different from the conventional oil recovery technology. Ultrasonic oil production technique is an effective method to enhance oil production with low cost, good applicability, and no environmental pollution. The core part of ultrasonic oil production equipment for Enhanced Oil Recovery is a high-power ultrasonic transducer. The continuous high-power ultrasound is used to treat the reservoir, which changes the pore structure, the physical property and the state of the fluid, thus improving the permeability and flows conditions of the reservoir, and increasing the oil yield and oil recovery. Ultrasonic oil recovery equipment includes the generation of high-power ultrasonic signals, long-distance transmission and the conversion of electrical energy to acoustic energy. In this paper, state-of-the-art on the development of ultrasonic oil production devices for Enhanced Oil Recovery in China is introduced. The purpose of this paper is to provide a reference for the development of high-power ultrasonic oil extraction equipment and its promotion in tertiary oil recovery technology.

Research on ultrasound-assisted demulsification/dehydration for crude oil

Crude oil demulsification and dehydration are important links in the process of crude oil exploitation, transportation, and refining. In recent years, with the development of crude oil exploitation, the content of colloid and asphaltene in crude oil has been increasing, and the properties of crude oil emulsion have become more stable. In addition, the development and application of oil recovery technology and the use of a large number of oilfield chemicals have made the composition of crude oil more complicated. The water content and salt content of oil produced fluid increase year by year, which aggravates the task of crude oil dehydration and desalination. Therefore, it is particularly important to study the demulsification and dehydration of crude oil. In this paper. Research on ultrasound-assisted demulsification/dehydration for crude oil in investigated. Results indicate that the demulsification effect varies with the increase of ultrasonic radiation time, but the difference is not significant; with the increase of temperature, the effect of ultrasonic on the demulsification of crude oil emulsion is decreased, or the advantages of ultrasonic can be fully displayed only at low temperature; ultrasonic power has a critical value, when it is lower than this critical value, ultrasonic wave acts as demulsifying agent, and with the increase of power, dehydration rate of the crude oil emulsion increases; when higher than the critical value, the separated oil and water can be re-emulsified; ultrasonic demulsification can both shorten settling time and reduce the amount of demulsifier; ultrasound is suitable for demulsification and dehydration of crude oil emulsions with high water content. Results also prove that chemical demulsifier has a better effect for crude oil demulsification /dehydration than that of ultrasonic treatment alone. In addition, recent progress on ultrasonic demulsification equipment is introduced. The purpose of this paper is to offer equipment and technical support for crude oil demulsification/ dehydration.

State-of-the-art on the technique of dispersive liquid-liquid microextraction

Dispersive liquid-liquid microextraction is a new sample pretreatment technology based on traditional liquid liquid extraction. In this paper, the application of low-toxicity extractants such as low-density extractants, auxiliary extractants, stripping agents and ionic liquids in this technology and the extraction modes such as solvent de-emulsification, suspension extractant curing, auxiliary extraction, back extraction, and ionic liquid-dispersion liquid microextraction, are summarized. In addition, the synergism of this technique with other sample preparation techniques, such as liquid-liquid extraction, solid-phase extraction, solid-phase microextraction, dispersive solid phase extraction, matrix solid-phase dispersion extraction, supercritical fluid extraction and ultrasound-assisted dispersive liquid-liquid microextraction is discussed.

Current knowledge and potential applications of cavitation technologies for the petroleum industry

Technologies based on cavitation, produced by either ultrasound or hydrodynamic means, are part of growing literature for individual refinery unit processes. In this review, we have explained the mechanism through which these cavitation technologies intensify individual unit processes such as enhanced oil recovery, demulsification of water in oil emulsions during desalting stage, crude oil viscosity reduction, oxidative desulphurisation/demetallization, and crude oil upgrading. Apart from these refinery processes, applications of this technology are also mentioned for other potential crude oil sources such as oil shale and oil sand extraction. The relative advantages and current situation of each application/process at commercial scale is explained.