Dispersion Of Oil In Water Research Articles

Design methodology for multi-parallel pipe separator (MPPS)

The Multiple Parallel Pipe Separator (MPPS) is a design for bulk oil-water separation that utilizes multiple horizontal pipe segments connected in parallel. Drainage of water is performed through tapping points on the pipe’s bottom. Pipe segments can be added in series (stacked) if needed. The aim of this study is to develop a design methodology for the MPPS that can be adapted to varying flow conditions.The methodology employs different types of models: flow pattern, drainage potential curves, and oil-water dispersion in pipe. The flow pattern model is used to determine the number of branches and pipe diameter to ensure segregated flow patterns. The batch dispersion-separation model is used to predict the thickness of the water oil and dispersion layers approaching the tapping point. The drainage potential model is used to determine tapping point separation performance and the number of required tapping points. All models are validated with experimental data available from previous and current experimental campaigns with inlet water cut, WCinlet, from 30 % to 90 % and total flow rate from 300 to 700 L/min.The results indicate that when the flow is oil-continuous (e.g., with an WCinlet, of 30 %) and the mixture velocity is high (e.g., 0.33 m/s), the droplet coalescence is limited, and the change of the emulsion layer thickness is less than 14 % of initial emulsion thickness. However, if the number of parallel branches is increased, the mixture velocity decreases, and consequently the residence time becomes longer enough to facilitate dissolving the emulsion layer. Furthermore, when the inlet water cut is low (e.g., 30 %), increasing the number of tapping points assists in extracting the water phase with a higher water cut. Conversely, when the inlet water cut is higher (e.g., 60 %), achieving a moderate water cut requires fewer tapping points.

Double-drying 3D lamellar-structured aerogel membrane for efficient oil-water separation and long-lasting antibacterial activity

Conventional oil-water separation membranes are difficult to establish a trade-off between membrane flux and separation efficiency, and often result in serious secondary contamination due to their fouling issue and non-degradability. Herein, a double drying strategy was introduced through a combination of oven-drying and freeze-drying to create a super-wettable and eco-friendly oil-water separating aerogel membrane (TMAdf). Due to the regular nacre-like structures developed in the drying process and the pores formed by freeze-drying, TMAdf aerogel membrane finally develops regularly arranged porous structures. In addition, the aerogel membrane possesses excellent underwater superoleophobicity with a contact angle above 168° and antifouling properties. TMAdf aerogel membrane can effectively separate different kinds of oil-water mixtures and highly emulsified oil-water dispersions under gravity alone, achieving exceptionally high flux (3693 L·m−2·h−1) and efficiency (99 %), while being recyclable. The aerogel membrane also displays stability and universality, making it effective in removing oil droplets from water in corrosive environments such as acids, salts and alkalis. Furthermore, TMAdf aerogel membrane shows long-lasting antibacterial properties (photothermal sterilization up to 6 times) and biodegradability (completely degraded after 50 days in soil). This study presents new ideas and insights for the fabrication of multifunctional membranes for oil-water separation.

ON DEVELOPMENT OF OIL FIELDS

Using a literature review, the article concludes that the displacement of oil by surfactants affects interrelated factors: by affecting the surface tension at the oil-water-rock interface, SAM adsorption occurs on the surface of pore channels, rock surface water and oil wetting changes, the oil layer is broken up and washed from the rock surface, the dispersion of oil in water stabilizes, the phase permeability of the porous medium changes, and finally, the forced displacement of oil by the water phase occurs. Keywords: gravity, elastic, capillary forces, adhesion, adsorption.

Experiment and simulation of the interface characteristics during the two-phase invasion between silicone oil and water

In this study, the interface characteristics during the two-phase invasion of silicon oil and water were investigated using high-precision optical experiments and molecular dynamics simulations. An experimental system composed of a CCD (charge coupled device) industrial camera and an optical microscope was designed to observe the interface state between the dispersed phase at the silicone oil-water interface. At the same time, the microscopic image and energy spectrum results of the silicone oil-water mixture were obtained using a cryo-scanning electron microscope (Cryo-SEM). The molecular dynamics method was also used to simulate the dynamic process of the mass transfer of the silicone oil-water mixture. Through experimental results and molecular dynamics simulations, the phenomenon of diffuse mass transfer during the phase invasion and the existence of silicon oil-water associations were confirmed. The results showed that the silicone oil and water molecules were associated with each other due to the hydrogen bonding and van der Waals interactions, but the interfacial association matter was loose and unstable. The C–H, Si–O, and H–O bonds were the main factor in the formation of the silicone oil-water dispersion association matter. The findings revealed the rationality of the dispersion associated substances at the silicon oil-water interface, and showed its microstructure characteristics. The study is expected to provide an insight for the study of silicon oil-water interface and enrich the emulsification and separation theories between silicon oil and water solutions.

Experimental quantification of the performance of a horizontal multi-pipe bulk separator of water and oil with crude spiking

Subsea water separation with pipe separators is crucial for ensuring efficient and environmentally responsible extraction of oil and gas from the seabed. In this study, in a process called as “crude oil spiking,” two concentrations of crude oil (e.g., 185 and 400 ppm) are added to Exxsol D60 to mimic the separation characteristics of real crude oil mixtures in a multi-parallel pipe separator. The pipe separator performance for water–oil bulk separation such as separation efficiency, water cut ratio, the flow pattern at the separator inlet, and the thickness and evolution of the fluid layers in the separator is evaluated and compared to the values when operating with unspiked Exxsol D60. Crude oil spiking significantly reduces the efficiency of the pipe separator and reduces the water cut ratio for oil continuous regimes (low water cuts) up to 49%. Water continuous regimes with water fractions 90% have the highest efficiency values; thus, these are not affected significantly by crude oil spiking. With crude spiking, the flow regime dispersion of oil in water and water in oil (Dw/o + Do/w) occupies more area in the flow pattern map than unspiked Exxsol D60. It was observed through visual inspection that crude oil spiking induces a thicker and more stable emulsion in higher flow rates (e.g., 700 L/min). Therefore, the spiked mixture needs more time to separate. The findings of this study can help in a better understanding of the applicability of pipe separators and the usage of spiked oils to extrapolate experimental results to real field conditions.Graphical abstract

Mechanisms of hydrate blockage in oil-water dispersions based on flow loop experiments

Hydrate formation poses a threat to the safety of petroleum transport in flow lines due to the risk of plugging. In this work, conceptual mechanisms of hydrate formation and plugging in oil–water systems are proposed, based on flow loop tests at 30%, 50% and 80% water cut (water fraction). The experiments were conducted with Kerdane oil, water (with 30 g/L of NaCl) and natural gas at 75 bar and 4 °C. The employment of several instruments, such as acoustic emission, permittivity, and flowmeter, to cite a few, allowed identifying the different flow patterns until hydrate blockage and detecting the phase that carries the hydrates. A model based on density measurement is proposed to calculate the fraction of hydrates flowing locally. It was observed that there are local accumulations of most of the hydrates in a small portion of the flowing volume, which, together with deposition, ends up leading to plugging.

A Dual-Parameter Measurement Method for Oil–Water Flow Based on a Venturi Embedded With Microwave Transmission Line Sensor

Accurate and real-time measurement of water cut (WC) and flowrate of oil–water flow is a critical factor in achieving intelligent digital oil field. In this article, a dual-parameter (WC and water flowrate) measurement method for oil–water flow is proposed based on a Venturi embedded with microwave transmission line sensor (V&MS). Dynamic experiments of horizontal fine dispersed oil–water flow are conducted. A two-dimensional finite element simulation model for V&MS under the fine dispersed flow is developed to simulate microwave phase outputs at 0%–100% WC. The simulation results agree with the experiments, providing a low-cost alternative to expensive oil–water dispersed flow tests. Furthermore, it is found that the flow patterns for 0%–10% WC and 40%–100% WC are water-in-oil and oil-in-water flows, respectively, but the flow patterns for 10%–40% WC are dispersions of water-in-oil and oil-in-water flow, and 20% WC is the transition point of the dominant continuous phase. When the water phase is continuous, V&MS has a higher sensitivity to phase signals. Finally, a WC prediction model (40%–100%) is developed by combining a modified Bruggeman model with microwave transmission line theory. Then, a discharge coefficient model is developed and the water flowrate is obtained by combining the pressure drop and the predicted WC. The absolute average relative deviation (AARD) of the predicted WC and water flowrate is 1.49% and 1.54%, respectively. The results suggest that appropriate sensing technology integration can offer a powerful solution for accurate and real-time determination of dual-parameter in oil–water flow systems.

Experimental investigation of liquid–liquid flow in an inclined pipe using dimensionless numbers

AbstractTwo‐phase flow is a common phenomenon in the energy industry, where flow patterns significantly affect heat transfer and pressure drop in different systems. However, there is no unique or comparable flow map because of its dependency on dimensional parameters. Therefore, an analysis using dimensionless numbers makes the results comprehensive. To do so, a series of liquid–liquid flow experiments (1296 experiments) were conducted in a transparent pipe at the different velocities of the phases. The flow patterns were captured using a high‐speed camera. The experiments were performed at eight different inclinations within the range of −20 to +20 degrees. Six flow patterns are observed at different inclinations; stratified flow with mixing at the interface (STMI), dispersion of water in oil (Dw/o), dispersion of oil in water (Do/w), dual continuous (DC), slug, and wavy stratified (WST), where the first five flow patterns are presented in the upward flow and the two last flow patterns disappear in some of the downward flow. The pattern of boundaries for each flow pattern in the upward flow shows dependency on inclination, while in the downward flow condition, a rather general format can be applied to most of the patterns. The analysis illustrates that gravity and buoyancy forces are the dominating forces in the system compared to other forces, such as viscous, inertia, and interfacial tension, which are due to the inclination of the pipe.

Development and assessment of a particle tracking velocimetry (PTV) measurement technique for the experimental investigation of oil drops behaviour in dispersed oil–water two-phase flow within a centrifugal pump impeller

The objective of the current work is to present the development of a Particle Tracking Velocimetry (PTV) algorithm for the analysis of oil drops behaviour in two-phase oil–water dispersions within a centrifugal pump impeller. The drop tracking was realized through high-speed camera images in a transparent pump prototype, which enabled the visualization of oil drops dispersed in water in all the impeller channels. The PTV algorithm is based on deep-learning techniques for image processing. The drops are detected by a combined U-Net and Convolutional Neural Network (CNN) method, with the former generating a binary image and the latter detecting valid oil drop contours. After detection, the Labelled Object Velocimetry (LOV) is adopted to calculate the instantaneous oil drop velocity. A synthetic image generator based on a Generative Adversarial Network (GAN) is then developed to assess the results from the U-Net, CNN, and LOV models. Additional validation studies are performed using the results from Perissinotto et al. (2019a). The results reveal that the presented deep-learning PTV algorithm is robust and provides consistent and reliable data for the dispersed oil phase in two-phase oil–water flows.

Post-extrusion physical properties, techno-functionality and microbiota-modulating potential of hempseed (Cannabis sativa L.) hull fiber

One-third of hempseed is composed of fiber, yet this major nutrient is far understudied than the seed's oil, protein, polyphenol or cannabinoid fractions. Here we provided a comprehensive and novel study covering the monosaccharide-linkage composition, physical, functional and microbiota-shifting properties of the fiber-rich (>77%) hempseed hull, which is a major industrial processing by-product. Xylose and cellulose-derived 4-linked glucopyranosyl linkage residue dominated the monosaccharide profile and 1D/2D NMR molecular assignments of hempseed hull. Processing with extrusion technology altered the particle size distribution, FTIR structural characteristics, X-ray diffraction crystallinity and thermal stability of hempseed fiber. Extruded hempseed fiber showed significantly greater soluble fiber content, water and oil binding capacity, dynamic modulus and flow viscosity values in oil and oil-water dispersions, delayed starch gelatinization and inhibited its retrogradation. Integration of 16S rRNA gene sequencing and the rapidly emerging metaproteomics revealed a higher population of Megasphaera elsdenii and Lactobacillus spp., along with their expressed ferredoxin and enolases respectively, in porcine faecal samples after fermentation with hempseed hull fiber. Higher production of propionic, butyric and valeric acid from the microbiota was further observed in fiber-treated faecal inoculum. Finally, the possible microbiota modulating-effect of fiber-bounded unique phenylpropionamides ( N - trans -caffeoyltyramine and lignanamides) from hempseed hull was assessed for the first time. • The effects of extrusion on the fiber profile of hempseed hull were investigated. • Linkage and NMR analysis revealed the molecular composition of hempseed fiber. • Functionality of hempseed fiber was tested in oil, water and starch matrices. • Hempseed fiber may alter gut microbial populations and their expressed proteins. • Microbiota and phenolic amides interaction were explored.

Pipe flow experiments of unstable oil-water dispersions with three different oil viscosities: Flow pattern, pressure drop and droplet size measurements

The transport of oil-water dispersions in petroleum production pipelines is difficult to predict and requires special attention since it affects the performance of the entire system. For future field developments it is required to generate accurate predictive models to guarantee an optimal field design. The purpose of this work is to present novel experimental data suitable for improving mechanistic flow models in future works. Oil-water pipe flow experiments were conducted in a stainless-steel flow loop with a L/D ratio of 3766, larger than any comparable setups reported in the literature and sufficient to obtain fully developed flow. A novel level of detail measurements included pressure gradients, density profiles and droplet size distributions.Three oils with different viscosities (oil A: 1.3 cP; oil B: 7 cP; oil C: 22 cP) and brine (3.5 wt% NaCl) as the water phase constituted the three fluid systems used. For each fluid system, several flow rates, and a wide range of water fractions were studied. The fluids were not stabilized by any type of chemical additives.The oil viscosity influences the dispersion behavior, especially for oil continuous flow. For higher oil viscosities the dispersion tends to be more homogeneous, and the pressure drop increases due to increasing wall friction. The droplet size decreases as the oil viscosity increases, presumably due to higher shear stress. Water continuous flows, on the other hand, are less affected by the oil viscosity. A strong drag reduction was found for dispersed flow of all three oils and both oil and water continuous flow. A simple model for the dispersion viscosity and drag reduction was developed based on additional bench scale characterization experiments. With this model the pressure drop could be predicted with good agreement.The data reported in this paper will facilitate the development and validation of mechanistic models for predicting oil-water flows. Previous modelling efforts have been hampered by a lack of detailed measurements, in particular droplet size measurements, hence we believe that this data will allow for significant advancements on the modelling side.

Experimental study of loss coefficients for laminar oil-water two-phase flow through micro-scale flow restrictions

Micro-scale flow restrictions have significant effect on the flow performances in microfluidic devices, porous media and biological processes. Two pairs of micro channels were fabricated by microfluidic method to experimentally investigate the irreversible pressure losses of laminar oil–water two-phase flow through two micro-scale flow restrictions. The hydraulic diameters of these two micro-scale flow restrictions are 72 μm and 33 μm, respectively. The oil contents of oil–water mixture vary from 0 % to 100 % and all the flow patterns are dispersed. By comparing the pressure drops between a micro channel with a built-in micro-scale flow restriction and the one without micro-scale flow restriction for a pair of micro channels, the irreversible pressure losses through a micro-scale flow restriction were determined. The results indicate that the local irreversible pressure loss is principally generated from the frictional dissipation effect instead of the acceleration and capillary effects for dispersed oil–water two-phase flow through the micro-scale restrictions with identical contraction and expansion geometries. As a dimensionless expression of irreversible pressure loss, the dependencies of local loss coefficient on the dimensionless parameters such as capillary number, Knudsen number, Reynolds number and restriction area ratio are concerned and discussed for the laminar oil–water two-phase flow through micro-scale flow restrictions. A new expression of local loss coefficient was proposed for laminar oil–water flow through a whole micro-scale flow restriction, by which the prediction results show good consistency with the experimental data.

Superoleophobic/Superoleophilic Janus Synergy Apparatus for Underwater Oil Capture and Collection

AbstractThe treatment of oily wastewater has always been an important problem in environmental management because the oil in the water is seriously harmful to the ecological environment. Although great progress has been made in the development of oil‐bearing wastewater treatment technology, there are still some problems in the treatment technology of dispersed oil in water, such as complicated treatment processes, high energy consumption, low treatment efficiency, secondary pollution, and difficult maintenance. Here, inspired by biological Janus synergy, a Janus synergy apparatus has been developed consisting of superoleophobic steel mesh (OSM) and superoleophIlic polyurethane sponge (IPS). By combining the underwater “capture oil” characteristic of OSM with the ability to store large amounts of oil of IPS, the two materials are combined to achieve an absorption rate above 95% of underwater oil in situ treatment. Due to the fact that the underwater oil can be directly captured, collected, and separated excellently, the prepared OSM/IPS Janus apparatus demonstrates the one‐step treatment of underwater oil, which needs neither more equipment nor additional power, and it is reusable and not easy to secondary pollution. Therefore, the development of this apparatus provides an economical and effective method for the treatment of underwater dispersed oil.

Applications of Machine Learning to Predict the Chord Length Distribution of Droplets in Oil–Water Dispersions

Applications of Machine Learning to Predict the Chord Length Distribution of Droplets in Oil–Water Dispersions

Effects of drag-reducing polymers on the flow patterns, pressure gradients, and drag-reducing rates of horizontal oil–water flows

The effects of drag-reducing polymers on the flow patterns, pressure gradients, and drag-reducing rates of oil–water two-phase flows were investigated using a horizontal acrylic pipe with an inner diameter of 25.4 mm and No. 7 white oil with a viscosity of 10.6 mPa∙s and a density of 888.9 kg/m3 at 25 °C. An aqueous solution of polyacrylamide (PAM), with a molecular weight of 19 million Daltons and a concentration of 100 ppm, was used. In the experiment, the oil and water velocities were 0.1-1.5 m/s and 0.1-1.6 m/s, respectively. The DRPs were found to extend the transition boundaries of stratified flow (ST), ST with mixing at the interface (ST&MI), dispersion of oil in water and water (Do/w&w), and oil and dispersion of oil in water (o&Do/w) but did not change the transition boundaries of dispersion of water in oil (Dw/o). The maximum drag reduction rate could be obtained by adding the DRPs to the dispersion of oil in water (Do/w). The drag reduction effect was closely related to the oil and water velocities. An empirical model for the friction factor was established.

Identifying the mechanism of the mixed-phase flow in the horizontal pipeline using computational fluid dynamic approach

In this study, computational analysis has been carried out using computational fluid dynamics (CFD). These calculations have been made to investigate the rheological behavior of the mixed-phase flow in horizontal pipelines. In order to study the shear stress in a vertical pipe, a new numerical model for oil-water dispersion in three dimensions has been developed. CFD software has been used to study the wall shear stress function and water droplet pressure. Using Reynolds numbers and the Navier-Stokes equations with k–turbulence factor to save energy, the flow range for the continuous process was explained. The results from a recent study on experimental methodology were simulated. In this study, the diameter of the tube is 40 mm and the length is 3.5 m and modeled and analyzed using Ansys software. Thus, the geometry has been imported and modeled using the CFD tool. The meshed model has been tested and converged accordingly. The primary data of the simulation have been verified with experimental results successfully. Oil droplet widths have previously been thought to be dependent on the flow Reynolds number, which was confirmed in this case study. Droplet diameter Dd was measured at 6 mm while the mixture moved at a speed of 1.9 m/s. It was found that the largest shear stress value was found at the top of the pipe, where the oil fraction (cut-off) was 0.3, in the simulation results for varied velocities (1.6, 2.5, 2.9 m/s) and oil fraction (cut-off) values. The results of the simulation analysis of the two-phase flow of crude oil for the horizontal pipe are wall shear stresses with different velocities for crude oil in the two-phase flow. As well as pressure drop at different velocities for the same fluids

A Review of the Processes Associated with the Removal of Oil in Water Pollution

Water plays an essential role in production and refining processes. Many industries that use petrochemicals also require water, especially for cleaning purposes. The wastewaters released by these processes are often rich in petroleum pollutants, which requires significant treatment prior to disposal. The presence of petroleum contaminants in rivers and oceans is a significant threat to human health, as well as to many animal species. A current challenge for most industries and conventional effluent treatment plants is compliance with accepted disposal standards for oil-polluted wastewater. Of particular importance is the processing of dispersed oil in water, as well as oil in water emulsion. Conventional oil and water separation methods for processing oil in water contamination have several technology gaps in terms of applicability and efficiency. The removal and effective processing of dispersed oil and emulsions from oily wastewater is a costly and significant problem. The objective of this paper is to provide a review of the principles associated with oil in water emulsion separation, with the aim of providing a more definitive understanding of the terminology, processes, and methodologies, which will assist the development of a more efficient, innovative and environmentally friendly process for the separation of oily wastewater.

Numerical Modelling of Dispersed Water in Oil Flows Using Eulerian-Eulerian Approach and Population Balance Model

Formation of a dispersed oil—water flow pattern is a common occurrence in flow lines and pipelines. The capability of predicting the size of droplets, as well as the distribution of dispersed phase volume fraction is of utmost importance for proper design of such systems. The present study aims at modelling dispersed water in oil flows in a horizontal pipe by employing a multi-fluid Eulerian approach along with the population balance model. To this end, momentum and continuity equations are solved for oil and water phases, and the coupling between the phases is achieved by considering the drag, lift, turbulent dispersion, and virtual mass forces. Turbulent effects are modelled by employing the standard k-ε model. Furthermore, a population balance model, based on the method of class, along with the breakup and coalescence kernels is adopted for modelling the droplet size distribution. The obtained numerical results are compared to the experimental data in literature for either the in situ Sauter mean diameter or water volume fraction. A comparison among the obtained numerical results and the published experimental data shows a reasonable agreement.

Oil Fraction Measurement of Nonuniform Dispersed Oil–Water Two-Phase Flow Based on Ultrasonic Attenuation

Oil volume fraction determination is important for the transportation and separation of oil–water dispersed flow in petroleum industry, for which ultrasound method is suitable with the advantages of good penetration and low cost. The existing ultrasonic attenuation methods are based on homogeneous media for the determination of phase fraction without considering the effect of inhomogeneity on attenuation. In this article, the fractal approach is introduced to modify the acoustic attenuation model by characterizing the inhomogeneity of the dispersed phase in pipe flow, which establishes the relationship between multi-frequency attenuation and droplet size distribution. Then, an improved covariance matrix adaptive evolutionary strategy (CMA-ES) based on the established attenuation model is proposed to estimate oil volume fraction, which combines restart strategy with local search strategy to enhance the search performance and avoid falling into local optimum. Moreover, a demodulation method based on swept-frequency chirp is designed for the time-varying dispersed oil–water pipe flow to quickly obtain the multi-frequency attenuation. The effectiveness of the fractal-based modified attenuation model and the improved CMA-ES is verified by numerical simulations and flowing experiments. The experimental results at different oil volume fractions and flow rates indicate that the fractal-based modified attenuation model can effectively reduce the impact of nonuniform distribution of dispersed phases on the attenuation measurement, and thus effectively improve the measurement accuracy of the oil volume fraction, especially for the dispersed flow in the horizontal pipe.

Liquid-Liquid Flow Pattern Prediction Using Relevant Dimensionless Parameter Groups

Accurate predictions of flow patterns in liquid-liquid flow are critical to the successful design and operation of industrial and geo-energy systems where two liquids are jointly transported. Unfortunately, there is no unified flow pattern map, because all published maps are based on limited ranges of dimensional parameters. Dimensional analysis was performed on oil-water horizontal flows, to obtain some relevant dimensionless parameter groups (DPG) for constructing flow pattern maps (FPM). The following combinations of DPG were used: (i) the ratio of mixture Reynolds number to Eötvös number versus water fraction, (ii) the ratio of Weber number to Eötvös number versus water fraction, (iii) the mixture Froude number versus water fraction, (iv) the water Froude number versus oil Froude number, (v) the ratio of gravity force to viscous force versus water fraction. From twelve published experimental studies, 2696 data points were gathered and analysed covering a variety of flow patterns including stratified, stratified mixed, dispersed oil in water, dispersed water in oil, annular and slug flows. Based on the performed analysis, it was found that flow patterns could occupy more than one isolated region on the DPG-based flow pattern map. None of the combinations of DPG can mark out all the considered flow patterns, however, some combinations of DPG are particularly suitable for marking out the regions associated with some flow patterns.