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In this paper, an effective method for the classification process simulation in 75¬mm hydrocyclone is considered. The simulation results and computational time are compared using Reynolds stress model (RSM) and different large eddy simulation (LES) subgrid-scale models as turbulence models, and the volume of fluid model (VOF) as a multiphase model. The Lagrangian discrete phase model (DPM) is used to simulate the classification process of particles. As the experimental result for comparison of simulation results, Hsieh's experimental data are used. When the different LES subgrid-scale models are used, the solution converges stably by various solution convergence methods without increasing the grid numbers or reducing the size of time steps than RSM model. As a result, it is confirmed that when an appropriate simulation method is applied with the LES-WMLES S-Omega model, more accurate axial water flow velocity distribution and particle classification simulation results can be obtained at a computational cost similar to that of using the RSM model.

The efficiency of grinding and flotation process in copper-molybdenum processing circuit, largely affected by performance of thickeners and hydrocyclones devices. The goal of this paper is to investigate the effect of the rate-limiting factors on the performance of these devices and consequently on grinding and separation efficiency of the molybdenum processing circuit. So, a full process mineralogical study have been carried out on outputs of thickeners and hydrocyclone of the molybdenite flotation circuit. According to the results, coarse-grained fractions (>50 μm) of the planar molybdenite will not necessarily be recovered by thickener and hydrocyclones. This is especially true for hydrocyclones when the inlet-load rate is high, i.e., the erroneous discharge of planar molybdenite particles from the overflow of hydrocyclone, as well as their floatability in the thickener overflow, can be attributed to the effect of particle shape and size. This issue harms the grade and recovery of flotation due to the increase in the amount of circulating load (regrinding) and consequently the generation of fine particles (Validerad;2022;Nivå 2;2022-09-07 (joosat);Funder: Research copper – molybdenum processing complex of Sungun

Isobaric surface is a characteristic feature generated during particle motion in the hydrocyclone. Its pattern and position can directly affect the separation performance, which has rarely been studied. In this study, the isobaric surface and flow field in the hydrocyclone with different apex/vortex ratios were investigated in-depth via numerical analysis, and the effects of air core on axial velocity and tangential velocity were explored. On that basis, the effect of apex/vortex ratio on the hydrocyclone's separation performance was analyzed. The results showed that both pressure and tangential velocity increased with the increasing apex/vortex ratio. Through theoretical study and numerical analysis, the isobaric surface in the forced- and free-vortexes showed parabolic and hyperbolic patterns, respectively. As the apex/vortex ratio increased, the isobaric surface moved towards the center of hydrocyclone, suggesting the expansion of free-vortex region, the shrinkage of the forced-vortex region, and thus the failure in particle gradation and separation. Air core can lead to the fluctuation of both axial and tangential velocities. The fluctuation frequentness increased with the apex/vortex ratio, causing the disorder of flow field and the reduction of separation efficiency. At an apex/vortex ratio of 3/2, fluid can only move downwards and the hydrocyclone no longer played the role of gradation. As the apex/vortex ratio increased, the content of fine particles in the underflow increased drastically, and most of coarse particles were discharged from the underflow port. In contrary, the cutting capability and separation precision increased with the decline of the apex/vortex ratio. Therefore, in order to obtain high-quality product, the apex/vortex ratio should be as small as possible under the premise of satisfying the separation requirement.

Hydrocylones offer a process intensified environment for rapid, high-throughput and relatively sharp particle classification or phase separation. One of the main performance limitations of hydrocyclone is bypassing of fines to the underflow. To address this limitation, a novel design modification of fitting thin concentric rings to the cylindro-conical section has been proposed. The Computational Fluid Dynamics (CFD) modeling based methodology has been adopted to validate the hypothesis. Predictions using Realizable k-e, Reynolds Stress Model (RSM), and Large Eddy Simulation Wall Adopting Local Eddy viscosity (LES-WALE) turbulence models has revealed that LES-WALE matched better with the experimental observations. The experimental data included overall performance parameters and detailed observations of axial and tangential velocity profiles across the hydrocyclone. The validated CFD model and the methodology was then used to predict the behavior of the proposed designs. They established that the modifications held promise in reducing the bypass with additional benefits of sharper separation curve and finer D50.

Overflow pipes are important components of hydrocyclones. The overflow products can carry huge amounts of residual energy when being discharged. In order to take full advantage of the residual energy and enhance hydrocyclone separation performance, this research designed a novel hydrocyclone by adding static mixing units with spiral elements in the overflow pipe. This study performed numerical simulations to investigate the effects of the install position of the spiral structure on the separation performance and inner flow field of the hydrocyclone. It can be concluded that both tangential velocity and pressure are first enhanced and then reduced by the elevation of the spiral structure. When the spiral structure is installed 30 mm away from the overflow pipe bottom, because of the hindrance of spiral elements, the discharge of coarse particles with the overflow are fully decreased and the quality of overflow products are enhanced.

This dissertation investigates the flow physics, turbulence structure, and particle classification process in hydrocyclones using large-eddy simulations of turbulent multiphase flow. Two types of hydrocyclones are considered. The first is a classifying hydrocyclone, and the second is a mineral flotation hydrocyclone, also known as an air-sparged hydrocyclone (ASH). Large-eddy simulations (LES) are conducted for multi-phase flow (air, water, and sand particles) so that the complex anisotropic turbulence of a swirling flow is computed correctly. The effects of mesh refinements on the mean flow and turbulence stresses are investigated, and (LES) results are validated by comparisons with experimental data for classifying hydrocyclone. The two-phase flow in air-sparged hydrocyclone has not been analyzed before. ANSYS CFX software V17.2 has been used to conduct the simulations. Firstly, large-eddy simulations have been conducted for two-phase flow (water and air) in a conventional hydrocyclone using the Eulerian two-fluid (Eulerian-Eulerian) and Volume-of- Fluid (VOF) models. Subgrid stresses are modeled using a dynamic eddy–viscosity model, and results are compared to those using the Smagorinsky model. The effects of grid resolutions on the mean flow and turbulence statistics have been thoroughly investigated. Five block-structured grids of 0.72, 1.47, 2.4, 3.81, and 7.38 million elements have been used for the simulations of a typical conventional hydrocyclone designed and tested by Hsieh (75 mm hydrocyclone) [1]. Mean velocity profiles and normal Reynolds stresses have been compared with experimental data. The results of the Eulerian two-fluid model agree with those of the VOF model. A fine mesh in the axial and radial directions is necessary for capturing the turbulent vortical structures. Turbulence structures in the hydrocyclone are dominated by helical vortices around the air core. Energy spectra are analyzed at different points in the hydrocyclone, and regions of low turbulent kinetic energy are identified and attributed to stabilizing effects of the swirling velocity component. Turbulent energy spectra in the different regions of the hydrocyclone have been analyzed. The energy spectra are calculated at two points near the air-water interface. They show a short inertial subrange where energy decays as f−5/3, followed by viscous damping where energy drops as f−7, where f is frequency. However, for the points located near the boundary where high turbulent kinetic energy is found, the energy spectra exhibit f^(−4) decay. Secondly, the two-fluid (Eulerian two-fluid) model and large-eddy simulation are used to compute the turbulent two-phase flow of air and water in a cyclonic flotation device known as an Air-Sparged Hydrocyclone (ASH). In the operation of ASH, the air is injected through a porous cylindrical wall. The study considers a 48-mm diameter hydrocyclone and uses a block-structured fine mesh of 10.5 million hexahedral elements. The air-to-water injection ratio is 4, and a uniform air bubble diameter of 0.5 mm has been specified. The flow field in ASH has been investigated for the inlet flow rate of water of 30.6 L/min at different values of underflow exit pressure. The present simulations show that the value of static pressure imposed at the underflow section strongly affects the distribution of air volume fraction, water axial velocity, tangential velocity, and swirling layer thickness in ASH. The loci of zero-axial velocity surfaces have been determined for different exit pressures. The water split ratio through the overflow opening varies with underflow exit pressure as 6%, 8%, 16%, and 26% for 3, 4, 5, and 6 kPa, respectively. These results indicate that regulating the pressure at the underflow exit can be used to optimize ASH's performance. Turbulent energy spectra in different regions of the hydrocyclone have been analyzed. Small-scale turbulence spectra at near-wall points exhibit f^(−4) law, where f is frequency. Whereas for points at the air-column interface, the energy spectra show an inertial subrange f^(−5/3) followed by a dissipative range of f^(−7) law. Thirdly, large-eddy simulation (LES) has been used to investigate the flow separation in multi-phase flow (gas, liquid, and solid) in a classifying hydrocyclone using the multi-fluid (Eulerian multi-fluid) model. The results of the CFD simulation are compared with the Hsieh [1] experimental data. The water phase is considered a continuous phase, while air and solid particles are considered dispersed phases. Drag between water-air and water-sand is the only considered interfacial force. The Schiller-Naumann and Wen-Yu models are used to model the drag, and the Gidaspow model is used to calculate the solid pressure term. Various particle sizes are tested in the hydrocyclone to investigate the underflow recovery percentages. The results agree with the experimental data for the particles of a diameter smaller than 20 μm, while the results vary based on the model for the large particles. Therefore, using the Wen Yu and Schiller-Naumann model for the drag model and the Gidaspow model for the solid pressure in the three-fluid model could give acceptable results for the small particles underflow recovery and volume fraction distribution. However, the models failed for large particles. Finally, the large particle size separation needs more investigation. Doctor of Philosophy Hydrocyclones are widely used in mining and chemical industries. They can be used as separation devices to separate solid or fluid particles based on their size or/and weight. They can also be used as flotation devices to capture certain mineral particles from a slurry of water and solid particles. The flow field within a hydrocyclone is complex as it involves flow of different phases of matter (liquid, gas, and solid). It is also a turbulent flow in which the velocity and pressure fluctuate in time with many frequencies. The efficiency of the hydrocyclone depends on its geometry and distribution of the velocity. Computer simulations are very efficient tools to predict and study the flow field in hydrocyclones. This dissertation used a computer simulations to explain how turbulence could affect the particle separation from the slurry inside the hydrocyclones. The water's velocity fields, swirling flow, air behavior, pressure distribution and turbulence statistics are analysed. Understanding the turbulence structure and statistics in hydrocyclones is important for particle tracking and dispersion. Also, turbulent structure affects the motion of the air bubbles and solid particles in the flow field, which eventually will affect the hydrocyclone's performance. In short, a more comprehensive understanding of the behavior of turbulence of hydrocyclones represents an important tool that can guide the design of hydrocyclones according to their use goals and will help engineers who model these processes to develop a better model.

As a principal reason for the deterioration of separation accuracy, the bypass effect in hydrocyclones has received widely concerned. This paper presents a numerical study about the effect of flat bottom structure width on the bypass effect with the respect of flow field characteristics, separation efficiency, and particle spatial distribution with a verified TFM model. Numerical results demonstrate that wide flat bottom structure increases the cut size and reduces the fine particles misplaced in the underflow. However, the excessive flat bottom structure width increases coarse particles misplaced in the overflow causing by the superior turbulence intensity and the entrapment of the internal swirling flow. A wide flat bottom structure width reduces the turbulence dissipation rate, while the split ratio first decreases and then increases, indicating that the bypass effect is controlled by the turbulence dissipation and does not comply with the trend of the split ratio.

Natural gas hydrate is a promising substitute energy resource for the future. Currently, the inefficient sand control technology impedes the commercialization of Natural gas hydrate. The main challenge lies in breaking the consolidation of Natural gas hydrate and sands, and then separating micrometer-sized sands from the drilling fluid. In this paper, we present a technology based on hydroscyclone that effectively breaks the consolidations and removes sand. We used polypropylene powders and silica sands as substitutes for the hydrates and sands, and we added cement to replicate the consolidation. Inside the hydrocyclone, the material particles receive a strong shear force from the 3-dimension rotating swirling flow field generated by the device, as well as a centrifugal force produced by their own rotation and revolution. With the high-speed camera, we observed the effect of these forces breaking the consolidation and separating sands. It was further noted that the proportion of residual polypropylene powders in the recovered materials were between 0.46% and 1.05% after the materials were processed by the hydrocyclone. The low residual content of polypropylene powders demonstrated the success of hydrocyclone technology in breaking the consolidation and effectively addressing the problem of sand control in the extraction of Natural gas hydrate and sands.

Reasonable numerical conditions are critical for the precision and accuracy of the numerical consequences of hydrocyclones. In this paper, the effects of resistance coefficient, wall roughness, and friction packing limit on particle velocity and distribution as well as the separation behaviors were studied in a cylindrical hydrocyclone using the two-fluid model. The results show that the friction packing limit and wall roughness can significantly influence the numerical results, whereas the effect of the resistance coefficient is negligible. As the friction packing limit increases from 0.4 to 0.55, the cut size gradually decreases with improving separation sharpness, and it reaches the minimum when the friction parking limit is 0.5. The wall roughness monotonously increases the cut size and reduces the separation sharpness. Simulation results were also compared with experimental data, and a reasonable prediction can be obtained with resistance coefficient, friction packing limit, and wall roughness height of 0.95, 0.5, and 50 μm, respectively.

In mineral processing circuits, the feed to hydrocyclone consists of different density particle system at varying degrees of liberation and sizes, leading to a multi-component system. These different density components' interaction affects the separation in the hydrocyclones, particularly at high feed solids concentrations. In this work, an attempt is made to account for bi-component particle interaction in a hydrocyclone at different feed solids concentrations (10–50 wt%). For classification experiments, pure silica and pure magnetite components were utilized as a ratio of 1:1 in the feed mixture. Customized orthogonal array experiments were carried out using three-spigot and pressure level for 3″ and 4″ hydrocyclones. Components' grade efficiency curves and the performance parameters (d50; Rf; Rs;α;β) were estimated and analysed using the Whiten Equation. The cut-size and beta parameter of the mixture and individual components witnessed to increase with increasing feed solids concentration. Suspension rheology and hindered settling rate studies were carried out to understand the influence of the fine and coarse particle interaction on the performance of the hydrocyclone processing bi-component mixture at different feed solids concentrations. The enhanced viscous flow at the conical region attributes the crowding effect and the dense medium effect near apex zone, and consequential coarse and fines inflections are observed. The lighter particle displacement in the presence of heavier component is further supported by the locus of maximum volume fraction and equilibrium position from the numerical analysis.

Wastewater is an inevitable product in industry. How to remove fine particles and enhance the impurity removal efficiency of the wastewater purification equipment has always remained a hotspot issue. In this study, a novel hydrocylone with bi-symmetrical involue inlet, thick-wall overflow pipes and conical segment structure was designed and compared with other hydrocyclones including different structures of inlets, i.e., The flow field and separation performance of the novel hydrocylone were investigated via numerical analysis, The simulation results show that the inner flow field in the novel hydrocyclone is more stable, accompanied with significant decline in both short-circuit and circulating flow rates; moreover, using the novel hydrocyclone, the tangential velocity, the axial velocity and the pressure increase significantly, which can make the particle obtain great centrifugal driving force and effectively reduce the number of dislocated particles. The recovery ratio of fine particles with the diameter of 1 μm also shows significant enhancement. Conclusively, using the designed novel hydrocyclone can obtain higher product quality. The present study can provide theoretical foundation for the design of a novel hydrocyclone.

A reliable non-contact pneumatic pressure regulator of a pressure hydrocyclone is offered. The regulator is installed in the area of ​​the sand nozzle. The pneumatic regulator of the standard pressure cylindrical-conical hydrocyclone provides non-contact thickening of the product in the area of ​​the sand nozzle. In the process of controlling the operation of the hydrocyclone along its axis, an air column is formed. Features of the regulator affect the formation of the air column of the hydrocyclone. The pressure in the air column is manometric. The task is to investigate the effect of pulp pressure at the inlet of the hydrocyclone, pulp thickening and air column pressure. Experimental studies were performed in the laboratory on a model of a standard industrial cylindrical-conical hydrocyclone HC360. The connection between the technological parameters of the hydrocyclone operation and the pressure in the air column has been studied. to establish possibilities of control of work of a hydrocyclone on pressure in an air column. The planning of the experiment in the laboratory on a hydrocyclone model was performed in the program Statgraphics Centurion XV. Experimental studies were performed for the optimal parameters of the angle and slit of the pneumatic regulator. The optimization criterion is chosen – the maximum effect of pulp thickening while minimizing local energy losses in the nozzle. In laboratory conditions, the change in pulp pressure and density at the inlet of the hydrocyclone over the entire operating range is simulated. The laboratory model of the hydrocyclone was made on a scale of M1:10. Flotation waste was used as pulp. Modeling of hydrocyclone operation as a part of water-sludge system at the concentrator is carried out. The density of the solid phase is 1500 kg/m3. The solids content at the inlet is 10 g/l. Samples were taken by volumetric measurement with a measuring vessel. A statistically significant relationship between the pressure in the air column of the hydrocyclone and the effect of pulp thickening in a standard cylindrical-conical hydrocyclone was established. The presence of the linear character of the dependence of the coefficient of thickening and pressure in the air column of the hydrocyclone with the pneumatic regulator is checked. The absence of a statistically significant effect of hydrocyclone supply pressure on the dependence of other selected factors was established. Experimental studies were carried out at the optimal design parameters of the pneumatic regulator according to the criteria of minimizing the loss of energy of air current in the nozzle and minimizing the volumetric flow of air.

A novel design of a hydrocyclone incorporating a disk deflector is proposed. This component allows the separation efficiency to be increased by reducing the probability of solid particles penetrating an outlet drain pipe, as well as improving the controlled performance of the hydrocyclone. CFD-modeling of the developed hydrocyclone was carried out along with an evaluation of the separation efficiency of the suspension on an experimental stand. Based on the obtained data, a 95 to 98% increase in the separation efficiency of mechanical impurities by a hydrocyclone with a deflector was confirmed.

The following performance between solid particle and liquid phases inside a hydrocyclone remains unclear. The purpose of this paper was to study the following pattern of solid-liquid phases in a hy...

In most mineral processing industries, hydrocyclone separators are operated at high feed solids content in the comminution circuits. Computational fluid dynamic (CFD) models developed so far are unable to predict the accurate classification behavior at high feed solid loadings. The dense slurry CFD model adopts algebraic slip mixture (ASM) model corrected with shear lift and hindered settling velocity-based drag forces to account for fluid-particle interactions and granular flow options for particle-particle interactions. The slurry rheology is modeled with a fine fraction-corrected Newtonian viscosity model. This model is utilized for running the multiphase simulations in five hydrocyclones (75-381 mm) at different design and operating conditions for the feed solids content varying between 0 and 65% by weight. Turbulence is modeled using the large Eddy simulation (LES) model. The results are analyzed in terms of air core diameter, water split, solid split, cut size, and sharpness of separation. In 75 and 250 mm hydrocyclones, the modified ASM model can predict accurate performance characteristics, including fine and coarse particle misplacement up to 30 wt % feed solids. Slight deviations are observed in the fine fraction recovery for the 50 wt % and higher feed solids content. Further, the same model is tested to predict the roping phenomena in a 381 mm hydrocyclone.

Tapered segment, the main separation region in a hydrocyclone, is mainly used to cut off the short-circuit flow. Generally, a single straight-line tapered segment is set in a conventional hydrocyclone, the effects of multi-curved-line combination-type tapered segment on the flow field in the hydrocyclone and the related separation performance have been poorly investigated. In this study, five different types of hydrocyclones with different tapered-segment structures (straight line, parabolic curve, hyperbolic curve, the combination of parabolic curve and straight line and the combination of hyperbolic curve and straight line), denoted as Type A, Type B, Type C, Type D and Type E hydrocyclones, respectively) were selected for numerical analysis. The simulation data were compared with classical experimental values by Hsieh et al. to validate the accuracy. Moreover, the changes of pressure fields, velocity fields, air columns, turbulence intensities and separation efficiencies in five different hydrocyclones were investigated in depth. The results showed that both the pressure drop and the tangential velocities of Type C and Type E hydrocyclones were higher than that of Type A hydrocyclone, while the pressure drop of Type B and Type D hydrocyclones was lower than that of Type A hydrocyclone. Under a higher pressure, fine particles moved toward the center more easily, thereby leading to the decreasing number of dislocated particles. Compared with conventional straight-line tapered segment, the combination-type tapered segment exhibited smaller axial velocity, which prolonged the retention time of particles in the hydrocyclone and contributed to full particle separation. The turbulence intensity can be weakened by changing the tapered-segment structure. The turbulence intensity in Type D hydrocyclone was lowest among the five hydrocyclones. In addition, the separation performance of hydrocyclones can also be enhanced by changing the structural form of the tapered segment. Type B hydrocyclone was featured by favorable separation performance and Type D hydrocyclone exhibited a small cutting size.

Hydrocyclone is one of the common equipment for solid-liquid separation. Although the hydrocyclone has a simple structure, it has many shortcomings. Among them, short-circuit flow and air core are two important factors that affect the separation performance. Many researchers have tried to weaken the short-circuit flow by changing the structure of the overflow pipe and the trajectory of the particles. This is certainly a feasible method to reduce the short-circuit flow. Is it possible to reduce the short-circuit flow by increasing the movement distance of the short-circuit flow and re-entering the short-circuit flow into the separation area without changing the structure of the overflow pipe? The answer is yes. In this paper, a thick-walled overflow pipe structure was proposed to increase the distance of the short-circuit flow into the bottom end of the overflow pipe.In the proposed structure, the particles in the short-circuit flow can be brought back into the separation area through the circulating flow at the bottom of the overflow pipe. During the working process, the hydrocyclone produces a unique phenomenon-air core. Although the air core does not participate in particle separation, it consumes energy and compresses the separation area. In order to further improve the separation performance of the thick-walled overflow pipe hydrocyclone, a central solid rod was traversed throughout the hydrocyclone to weaken the air core. In addition, FLUENT was used to numerically analyze the thick-walled overflow pipe hydrocyclone with an inserted solid rod in the center. Moreover, we investigated the effect of the solid rod with different diameters on the separation performance of the hydrocyclone. The numerical simulation was verified by comparing the simulation data with the classic data. The results showed that the pressure distribution of the thick-walled overflow pipe hydrocyclonewas more reasonable. The inserted solid rod significantly improved, the pressure distribution. Compared with the conventional hydrocyclone, the short-circuit flow rate of the thick-walled overflow pipe hydrocyclone was reduced by 8.09%. The cutting size of the particles can be adjusted by changing the diameter of the solid rod. When the diameter of the solid rod was 5–6 mm, the cutting size was in the range of 11.6–12.2 μm. When the diameter of the solid rod exceeded 6 mm, the cutting size gradually increased. The appropriate diameter of the solid rod can improve the separation accuracy of thick-walled overflow pipe hydrocyclone, resulting in thinner and higher quality products.

Polymer flooding technology is widely used to enhance the oil recovery, but it increases the viscosity of the produced liquid, making the subsequent water treatment more challenging. Application of polymers impacts separation performance of hydrocyclone, which is an important equipment of produced liquid preseparation and sewage treatment in oil fields. In this work, the effect of polymer solution concentrations on the separation performance of hydrocyclone was studied by using sensitivity analysis. The sensitivity was calculated by numerical simulation, and the influence of polymer concentration on velocity field, pressure field, oil volume fraction, and separation efficiency of hydrocyclone was evaluated. The prototype was processed according to the similarity principle of fluid mechanics, and the relevant laboratory tests were carried out to verify the accuracy of simulation results. Within the tested range (100‐1000 mg/L), the increase of polymer solution concentrations caused adverse impacts on the velocity field, pressure field, and oil volume fraction of the hydrocyclone. When the concentrations of polymer solution reached 800 mg/L, the separation efficiency was reduced to less than 60%. The sensitivity sequence obtained by calculation is as follows: underflow outlet pressure drop > overflow outlet pressure drop > axial velocity > radial velocity > tangential velocity > pressure drop ratio. The change of pressure drop at underflow and overflow outlets was the primary cause for poor separation performance of hydrocyclone. The work can be used to guide the design and application of hydrocyclone for efficient treatment of polymer‐containing treatment liquid.

The intake of natural water or waste water from a depth exceeding the suction height of centrifugal pumps is mainly carried out due to additional water supply at the suction of the pump. However, this process becomes more complicated if it is necessary to purify water from mechanical impurities. The purpose of the presented work is to consider this issue based on the development and study of the parameters of an ejector water intake treatment plant equipped with a pressure-vacuum hydrocyclone. The main contribution of the ongoing research is the establishment of the technological parameters of the installation, and their features in the pressure-vacuum mode of operation, in contrast to the known pressure and vacuum hydrocyclones separately. In terms of methodology, the main parameters of the developed installation were established during the testing of its prototype on a specially built stand using well-known regulatory guidelines in the hydraulic research system. As a result of the study, the nature of the change in pressure inside a cylindrical–conical hydrocyclone, with established design dimensions and the patterns of formation of vacuum and pressure-vacuum modes depending on the initial parameters, was revealed. The data obtained to determine the effect of technological parameters of ejection and the characteristics of the supplied water with impurities on the operating mode of the hydrocyclone confirm the efficiency of water intake and purification. A rational mode of joint operation of the elements of a closed system is achieved at the maximum value of the installation efficiency and ensuring low specific energy consumption per 1 m3 of treated water.

Natural Gas Hydrate (NGH) downhole hydrocyclone separator is one of the core components of solid-state fluidized mining method, and its adaptability to NGH reservoir parameters directly determines ...

The misplacement of particles in the hydrocyclone is the primary reason for the deterioration of separation sharpness and has obtained extensive attention. This paper presents a study on the flow field characteristics and separation performance of cylindrical hydrocyclones with different spigot upper diameter by the TFM model. The numerical results indicate that the spigot upper diameter has a slight effect on the tangential velocity, while a smaller spigot upper diameter implies a higher turbulence intensity and an immense internal swirling flow region, causing more coarse particles misplaced in the overflow. However, an oversize spigot upper diameter denotes a superabundant circulating flow, reducing the fine particles misplaced in the underflow, and increasing coarse particles misplaced in the overflow. Under the combined action of the internal swirling flow and the circulating flow, both undersize and oversize spigot upper diameter generates a negative classification performance of the cylindrical hydrocyclone.

Maximizing separation sharpness is critical for the design and operation of hydrocyclones but remains difficult to achieve. This work presents a numerical study on the relationship between separation performance and the characteristics of axial velocity wave zone to understand the reasons for the limited separation sharpness. The results showed that this zone is featured as an inherent transition region, with extensive secondary vortices formed between inner and outer spiral flows. The presence of this zone adversely affects the fluid-solid momentum transfer, causing prolonged residence time and accumulation of intermediate-sized particles. The separation sharpness shows a strong dependence on the characteristics of axial velocity wave zone, which are further controlled by geometric parameters. Increasing the symmetry of flow field and optimizing the spatial distribution of this zone can help increase the separation sharpness while its size shows little effect.

Most cold-climate biological nutrient removal facilities experience poor settling mixed liquor during winter, resulting in treatment capacity throughput limitations. The Metro Wastewater Reclamation District in Denver, Colorado, operated two full-scale secondary treatment trains to compare the existing biological nutrient removal configuration (Control) to one that was modified to operate with an anaerobic selector and with hydrocyclone selective wasting (Test) to induce granulation. Results from this evaluation showed that the Test achieved significantly better settling behaviour than the Control. The difference in the mean diluted SVI30 between the Test and Control were statistically significant (P < 0.05), with values of 77 ± 17 and 135 ± 25 mL/g observed for the Test and Control respectively. These settling results were accompanied by differences in the particle size distribution, with notably higher settling velocities commensurate with increasing particle size. The degree of granulation observed in the Test train was between 32 and 56% of the mass greater than ≥250 μm in particle size whereas 16% of the mixed liquor in the Control was ≥250 μm over the entire study period. The improved settling behaviour of the Test configuration may translate into an increase of secondary treatment capacity during winter by 32%. HIGHLIGHTS Inducing granulation in a full-scale continuous flow activated sludge system was possible with the application of both biological and physical selection pressures.; Observations in this study could translate to a cost effective intensification solution versus traditional expansion for WRRFs evaluating capacity needs.

In consideration of offshore oil spill accidents, a mechanical method is a kind of widely used treatment methods to recover spilled oil at sea. It also has the advantages of low cost, convenient use, and environmental friendliness. In order to improve the recovery efficiency and oil content of liquid recovered, a novel mechanical spilled oil recovery philosophy coupling surface vortex and hydrocyclone separation was proposed, and a small-scale prototype was manufactured. Medium crude from Bohai oil field was applied as spilled oil to test the recovery property of the prototype skimmer. The experiment results show that the novel skimmer is able to recover spilled oil effectively on the sea surface and speed up the process of recovery. Pressure of overflow pipe is sensitive to pump frequency, flow rate of inlet, and split ratio. In addition, oil content at the overflow port is influenced by spilled oil amount on the surface and split ratio. Besides, linear relationship is found between the recovery efficiency and the split ratio. The experimental study can provide a technical reference for the treatment of a small amount of spilled oil on the water surface and also has great significance for the design of spilled oil recovery equipment.

De-oiling hydrocyclones are extensively applied in oilfield wastewater purification for fluid separation, because of their efficient and rapid processing performance. However, it is difficult for a...

Influences of the vortex finder diameter and length on the performance of a 50 mm diameter hydrocyclone for particle separation were investigated comprehensively, and the grade efficiencies of part...

The misplacement of coarse particles in overflow and fine particles in underflow are common problems in hydrocyclone separation. This study aimed to propose a hydrocyclone with a spiral inlet struc...

Technologies associated with the use of a membrane bioreactor (MBR) is becoming one of the dynamically developing directions in the wastewater disposal system. However, a certain part of the used design of membrane units are exposed to mechanical contamination, which significantly impairs their performance. This is especially noticeable when working at wastewater treatment plants, where the required degree of preliminary cleaning from solid mechanical particles and suspended solids is not provided. The purpose of the work is to improve the process of post-treatment of urban wastewater and protect the membrane element of the installation from clogging with coarse impurities and wear, with an overestimated concentration of suspended solids. The essence of the improved membrane technology of wastewater treatment consists in the preliminary capture of heavy and suspended particles with a size of more than 0.03 microns in a hydrocyclone, followed by water treatment in a chamber of a membrane bioreactor of modern design. The operating conditions of the membranes were determined by the operating modes and parameters of the bioreactor, in particular, by the degree of formation of colloidal compounds in it, which adversely affect the permeability. The density of the initial water varied within 1.059 - 1.078 g / cm³, and the content of solid particles was up to 0.3 mm. activated sludge was filtered under vacuum on a Buchner funnel through a thin layer of cotton wool and gauze. During the tests, the indicators for capturing suspended solids were 5.0 - 9.0 mg / dm³, while, when working without a hydrocyclone, they were equal to 27 - 30 mg / dm³. The maximum performance of the hydrocyclone is provided at an inlet pressure of 225-300 kPa, and the pressure loss in the hydrocyclone chamber is 7.9 - 9.0 kPa.. It has been established that additional preparation of waste water for the post-treatment process using a hydrocyclone increases the cleaning capacity of membrane elements by reducing the load of accumulation of coarse impurities on the membrane surface.

Production of chemical pulp is accompanied by various impurities in addition to the cellulose fibres produced. The impurities are mainly due to lignin fragments and wood resin components in the wood. The possibility of removing impurities such as fines and extractives at the early production stages by hydrocyclone fractionation was investigated. A sample of unbleached eucalyptus chemical pulp was fractionated using a hydrocyclone at feed consistencies of 0.1% to 1.0% and mass reject rates of 5% to 41%. Fractionation efficiency was assessed by measuring changes in consistency, Canadian Standard Freeness, fibre morphology, and extractives (wood resin) in the fibres. It was found that fractionating at consistencies of 0.6 - 1.0% at mass reject rates of 5 – 20% produced acceptable fractionation, with simultaneous removal of extractives associated with fibre fines. Fractionation of unbleached chemical pulps under these conditions could produce chemical pulps with enhanced bleaching and further processing properties.

The filtering hydrocyclone is a device designed by our research group, in which the wall of a hydrocyclone section (conical or cylindrical) was replaced by a filtering wall. In the present work, the influence of geometric variables of a filtering cylindrical hydrocyclone (FCyH) on its separation performance was investigated. The performance of FCyH and conventional hydrocyclones of same geometry were compared. The main difference observed between FCyH and conventional hydrocyclones was in the Euler number; some configurations of FCyH showed decreases by 29% for that response. Furthermore, an optimization study was developed using the Differential Evolution Algorithm (DE), which aimed to find two categories of hydrocyclones: Case 1 (minimum Euler number) and Case 2 (maximum total efficiency). The Case 2 optimized hydrocyclone (FCyH-OT2) showed total efficiency 8.1% higher than the equipment with the highest efficiency of the experimental design (FCyH-A), providing in addition, a reduction of 13.2% in Euler number.

A novel oilfield high-oil-recovery water injection treatment device, the hydrocyclone oil removal device, was developed to treat oilfield sewage in the oil phase. It addresses the problems of high oil content in oilfield sewage, direct discharge of contaminants to the environment, and reduction of formation water absorption capacity by reinjection formation. An experimental verification and numerical simulation of the device were carried out to analyze its mechanism and influencing factors. An analysis of the flow path, phase distribution, velocity distribution, and pressure distribution of oil and water revealed the oil removal mechanism of the hydrocyclone oil removal device: automatic separation of oil and water could be realized by using the physical properties of the fluid, the special structure of the equipment, and the appropriate operating parameters. The influence of the inlet oil concentration, flow, pressure, and oil droplet size on the separation efficiency was investigated. The inlet flow, pressure, and the oil droplet size were found to be directly proportional to the separation efficiency, and the oil concentration was found to be inversely proportional to the separation efficiency. These results could further the efficient application of the high-oil-recovery water injection treatment device. The research results also have important engineering value for the efficient treatment and recycling of oil and gas field wastewater.

The goal of the project is to develop and use a hydrocyclone sand trap to improve the operation of a mini hydroelectric power station. In contrast to the existing design of a similar type of hydroelectric power station, a bulky sump for water purification has been replaced with an efficient hydrocyclone device. Due to this, a simplification of the design of the HPP is achieved, an increase in the degree of sand collection from the composition of the water used. Research methods. The initial data for the calculation were taken: the flow rate of water passing through the hydrocyclone and the pressure drop at the inlet and outlet of the hydrocyclone. Computer simulation of the process was carried out using the SolidWorks software (flow simulation). The main technological parameters and a rational mode of operation were established by testing experimental samples both in laboratory and in production conditions. Research results. In the established mode, the density of clarified water is equal to 1.009 ... 1.050 t / m3, and the degree of purification is 91 ... 97%. Replacing a bulky reinforced concrete sump with hydrocyclone sand traps of a simplified design reduces the cost of building a water treatment unit from 30% (existing) to 7%. This makes it possible to expand the volume of development of small hydroelectric power plants, especially in mountainous conditions.

Hydrocyclones are devices used in numerous areas of the chemical, food, and mineral industries to separate fine particles. A hydrocyclone with a diameter of d50 mm was modeled using the commercial Simcenter STAR-CCM+13 computational fluid dynamics (CFD) simulation package. The numerical methods confirmed the results of the different parameters, such as the properties of the volume fraction, based on CFD simulations. Reynolds Stress Model (RSM) and the combined technique of volume of fluid (VOF) and discrete element model (DEM) for water and air models were selected to evaluate semi-implicit pressure-linked equations and combine the momentum with continuity laws to obtain derivatives of the pressure. The targeted particle sizes were in a range of 8–100 microns for a dewatering application. The depth of the vortex finder was varied to 20 mm, 30 mm, and 35 mm to observe the effects of pressure drop and separation efficiency. The split water ratio increased toward a 50% split of overflow and underflow rates as the length of the vortex finder increased. It results in better particle separation when there is a high injection rate at the inlet. The tangential and axial velocities increased as the vortex finder length increased. As the depth of the vortex finder length increased, the time for particle re-entrainment into the underflow stream increased, and the separation efficiency improved.

Hydrocyclone with guide vanes is one type of swirl flow launching device without energy input. For researching the flow characteristics of that hydrocyclone, the flow distribution of the sections and their variation along the flow were studied using numerical simulation and physical experiment. In addition, the flow field was convenient to be divided into three-dimensional velocities: axial velocity, circumferential velocity, radial velocity and the static pressure. The result showed that the water flow had obvious diversion by the effect of guide vanes. The axial velocity varied into the distribution of higher values emerging away from the pipe wall and the surfaces of guide vanes, and the value was higher on downstream surfaces than upstream surfaces of the guide vanes. The radial velocity’s direction pointed at the axis of pipe on upstream surfaces, and pointed at the pipe wall on the downstream surfaces of the guide vanes; the influenced range was larger in sections along the flow. The circumferential velocity increased along the flow, closing the distorted guide vanes; the value of that velocity was larger closer to the guide vanes, especially the downstream surfaces of the guide vanes. The static pressure decreased along the flow, and the value was larger on the upstream surfaces than the downstream surfaces of the guide vanes. The results can provide some theory references to improve the construction of the hydrocyclone.

The main application of hydrocyclones in most industry sectors is the separation of particles from liquids. For thickening, however, the separation properties of the cyclone should be adjustable, which requires a different operating mode. Therefore, we investigated an add-on thickening module, consisting of a conical plug and a secondary vortex finder in the underflow of the hydrocyclone. Laboratory scale experiments are carried out to investigate the function of the concept of annular gap modification by the use of the thickening module. In the second step, we transferred this concept to industrial scale for field tests at a municipal wastewater treatment plant. In the field tests, geometrical properties (annular gap modification) and operational parameters (volume flow rate, sludge type) were investigated. The results show that thickening in terms of increasing the total solids content of sludge is possible with the modified hydrocyclone. In the field tests, a thickening factor (total solids content of thickened sludge related to feed sludge) of 1.31 (average) was reached for digested sludge. Hence, a hydrocyclone could be a promising addition in wastewater treatment plants for dewatering of sludge.

A mathematical model of the process of degassing of nonlinear viscoplastic fluids in a cylindrical hydrocyclone is developed, taking account of inertial and Coriolis forces and virtual mass of the fluid. A system of differential equations in partial derivatives that describes the degassing process is reduced to a system of ordinary differential equations and solved by numerical method. The influence of the separation factor and rheological properties of the fluid on the degree of gas bubbles extraction is analyzed. The obtained data can be used to design equipment for degassing of oil in preparation for its transportation.

Hydrocyclones are widely used in mineral processing to separate coarse and fine particles. Despite the effect that their performance can have on downstream operations, they are not generally monitored or controlled, since online estimation of particle size is challenging. In this paper, it is shown that a pretrained convolutional neural network can be used to provide useful estimates of the particle sizes in the underflow of hydrocyclones. More specifically, GoogLeNet is used in a transfer learning mode to extract features from images of the underflow of a hydrocyclone, which can then be used as predictors of particle size in a regression model. The model was able to explain approximately 85% of the variance in the particle sizes associated with the underflow images. However, with additional training of the last feature layers of the model, it was able to explain approximately 91% of the variance of the particle sizes.

In order to reduce the frequency of marine environmental pollution accidents, marine oil-water separation numerical simulation method is developed. The oil-water separation hydrocyclone is used for emergency treatment to deal with the marine surface oil pollution, and the oil-water separation optimal control parameter calculation method based on the mathematical model of the flow field is used to simulate the oil-water separation performance of the device. The simulation results show that when the split ratio is 4.1%, the inlet pressure is 0.15MPa, the overflow pipe diameter is 3 mm, the oil droplet size is 101, and the large vertebral angle is 27, the hydrocyclone has good separation performance. Under these conditions, this method can be used as a reference method for dealing with oil spills in the ocean and has certain application value.

Sediment and turbidity from construction sites are primary causes for surface water quality impairment. Much of the sediment leaving construction sites consists of silt an clay that can carry substantial amounts of nutrients and pollutants. Increased turbidity can limit sunlight penetration into water by both adsorbing and deflecting light. Coagulation is the most widely used for microparticle removal in water and wastewater treatment facilities. Coagulants are added to transform dispersed particles into aggregate floc for subsequent removal by sedimentation. Instead of impeller type mixer for coagulation, coagulants injection hydrocyclone and was used for coagulation. Hydrocyclone effluent and underflow are recycled in retention basin for flocculation and settling. To determine the optimum Chitosan dosage for treatment of construction sites high turbidity, tunnel construction site, aggregate extraction sediment, clay-silt soil samples were used for Jar test. Chitosan, obtained by deacetylation of chitin, is described as a cationic polyelectrolyte and is expected to coagulate negatively charged suspended particles found in turbid waters. The structure of Chitosan is very similar to that of cellulose, and is biodegradable. Chitosan coagulants also produced larger flocs of better quality and faster settling velocity, dewatering. Therefore, Chitosan has become necessary to develop more efficient and environment-friendly flocculants for removal of turbidity in waters. As the results of Jar test (rapid mixing 1min, slow mixing 3 min, settling 15 min), the optimum Chitosan dosage was 10~15 mg/L for clay silt soil. Because of the effectiveness of Chitosan in removing turbidity was independent on pH, the hydrocyclone coagulation system would be simple. The results of lab scale retention basin with hydrocyclone coagulation system test indicate that the ranges of removal efficiency of turbidity, SS were 81.5~96.1%, 84.9~95.1%, respectively. Hydrocyclone coagulation system would have possibility with compact design, because of the increase of floc size and reduces the settling time.

Hydrocyclones are widely used in industry and CFD has been used to compute them. Reynolds stress turbulence models (RSM), which are computationally costly and oftentimes hard to converge, are often...

An increase in the volume of industrial effluents, ship accidents, oil breakthroughs at drilling rigs lead to a deterioration in the quality indicators of water in open water sources, including in terms of the content of organic compounds and oil products. The water used for irrigation of agricultural crops, according to most indicators, must meet the water quality requirements for household and drinking purposes. Thus, the total content of oil products in the irrigation water should not exceed 0.1 mg / l. The use of water with the MPC excess leads to significant changes in the morphological properties of the soil, reduces the biological productivity and phytomass of the plant cover. Therefore, the issue of improving machines and devices used in water treatment technologies to increase their reliability and efficiency is one of the topical areas of the research. The aim of the study is to develop a hydrocyclone complex cleaning apparatus, which implements combined processes of capturing both coarse and finely dispersed impurities. Unlike the standard design, the hydrocyclone is supplemented with a filter element installed on the drain pipe, which provides additional water purification from fine mechanical impurities, and a sorption filter designed to remove oil products and other floating organic compounds from water. The proposed hydrocyclone unit provides a comprehensive purification of irrigation water from various types of impurities, due to the combined processes of centrifugal separation and sorption filtration. It eliminates the multistage process of water purification, and regeneration of the sorption filter by the action of centrifugal forces or pressure does not require the use of special regenerating solutions, which increases the manufacturability and environmental friendliness of the water treatment process.

An industrial water injection hydrocyclone was adopted in the Taixi coal preparation plant to overcome the shortcoming of fine particle entrainment in the underflow and improve the grading efficien...

Water/oil emulsion is considered as the most refractory mixture to separate because of the interference of the two immiscible liquids, water and oil. This research presents a study of dewatering of water / kerosene emulsion using hydrocyclone. The effects of factors such as: feed flow rate (3, 5, 7, 9, and 11 L/min), inlet water concentration of the emulsion (5%, 7.5%, 10%, 12.5%, and 15% by volume), and split ratio (0.1, 0.3, 0.5, 0.7, and 0.9) on the separation efficiency and pressure drop were studied. Dimensional analysis using Pi theorem was applied for the first time to model the hydrocyclone based on the experimental data. It was shown that the maximum separation efficiency; at split ratio 0.1, was 94.3% at 10% concentration and 11 L/min flow rate; at 0.3 split ratio, was 70.8% at 10% concentration and 11 L/min flow rate; at split ratio 0.5, was 82.1% at 12.5% concentration and 11 L/min flow rate; at split ratio 0.7, was 70% at 11 L/min, for 5%, 7.5%, and 12.5% concentrations; at 0.9 split ratio was 96.8% at 11 L/min flow rate and 5% concentration. The maximum separation obtained within these ranges of variables was 96.8% at 0.9 split ratio, 11 L/min flow rate and 5% concentration. The maximum pressure drop recorded was 3.6 bar at split ratio 0.1 and 11 L/min flow rate for all concentrations. The correlations obtained by the dimensional analysis were; at split ratio 0.1, at split ratio 0.3, at split ratio 0.5, at split ratio 0.7, and at split ratio 0.9. As an average for all the studied variables.