Separation Efficiency Of Hydrocyclone Research Articles

Effect of gas on separation performance of an axial hydrocyclone for preliminary water separation

Hydrocyclones have become the preferred solution to the high water cut of fluids produced in oil wells. However, the gas associated with these fluids affect the separation efficiency of hydrocyclones. In the present study, the impact of gas on flow field stability and oil–water separation performance of an axial hydrocyclone for preliminary water separation was investigated theoretically and experimentally. The results show that small amount of gas enhanced oil-water separation, while large amount impeded it. The oil concentration of the outflow water first decreased and then increased with the increasing gas liquid ratio. The gas liquid ratio corresponding to the inflection point was 5% in slug flow regime and 8% in bubble flow regime. For different split ratios and water cuts, the impact of the GLR on the separation performance followed similar patterns. The gas decreased the oil concentration by 8.8% at most when the GLR was <5%. It decreased the oil concentration by 12.5% at most when the GLR was 7%–30%. The results obtained in this study show the relevant effect of gas in the functioning of hydrocyclones for the preliminary water separation and the importance of the reasonable control of GLR to reduce the impact in the separation performance.

Separation performance of hydrocyclone oil removal device influenced by oil droplet trajectory and oil drop characteristics.

Cyclone separation is an effective method for the treatment of oily wastewater from offshore oil production platforms. There is a lack of research on the impact of dispersion on the separation efficiency of current liquid-liquid separation hydrocyclones. A numerical simulation method was used to study the effect of the oil droplet characteristic parameters on the separation efficiency of a hydrocyclone oil removal device. An analysis of the trajectory of oil droplets revealed the oil removal mechanism of the hydrocyclone oil removal device: under the guidance of tangential velocity, the oil-water mixed fluid in the equipment generates different centrifugal forces due to the density difference, so oil and water adopt different flow paths to flow out. The effects of the particle diameter, velocity, and concentration of the inlet oil droplet on the separation efficiency were investigated. The droplet size had a positive effect on the separation efficiency, the oil concentration had a negative effect on the separation efficiency, and the speed of the oil drop was directly proportional to the separation efficiency within a certain range. These studies improved the basis for the efficient application of hydrocyclone oil removal devices.

Determination of Separation Efficiency of Hydrocyclone Used Pre-Filter in Micro Irrigation at Different Inlet Velocities and Sand Diameters

Hydrocyclones are used as pre-filter to reduce suspended particles in irrigation water on the subsequent filters. The aim of the study was to determine separation efficiency (SE) of hydrocyclones, called H1, H2 and H3 according to inlet/outlet diameters, at water velocities of 1.0 (V10), 1.5 (V15) and 2.0 (V20) ms-1, and sands diameter of 0.5 (D05), 1.0 (D10), 1.5 (D15), 2.0 (D20) and 2.5 (D25) mm. Therefore, a hydrocyclone laboratory test system was constituted using a water tank, motor pump, inverter, flowmeter, valve, hydrocyclone, disk filter, and polythene pipe. Separation efficiencies were calculated by dividing amounts of sand collected in collection box by feeding amount of sand. The lowest average separation efficiency was determined as 37% at H1V10D05 treatment and the highest ones as 97% at both H2V20D10 and H3V20D20, and the other ones changed between two values. Average separation efficiencies resulted as 69%, 88% and 88% for H1, H2 and H3 hydrocyclones, and 71%, 84% and 90% for V10, V15 and V20 water velocities, and 78%, 82%, 82%, 83% and 84% for D05, D10, D15, D20 and D25 sand diameters, respectively. Besides these, average separation efficiency for three parameters was 82%. Since the inlet size of H2 is smaller than that of H3 and its SE was higher than that of H1 and equal to that of H3, the most suitable hydrocyclone was determined as H2 to be used in the micro irrigation. The highest average separation efficiency was 90% at a water velocity of 2.0 ms-1. According to separation efficiency of the hydrocyclone, the optimum water velocity in the inlet of the hydrocyclone was determined as 2.0 ms-1. The separation efficiency of hydrocyclone showed that the efficiencies increased with increasing water velocity from 0.5 ms-1 to 2.0 ms-1 and sand diameters from 0.5 to 2.5 mm. In separation efficiency for micro irrigation, water velocities and suspended materials play crucial roles as well as hydrocyclone mechanical properties.

Investigating effect of polymer concentrations on separation performance of hydrocyclone by sensitivity analysis

AbstractPolymer 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 &gt; overflow outlet pressure drop &gt; axial velocity &gt; radial velocity &gt; tangential velocity &gt; 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.

A comprehensive insight into the application of machine learning approaches in predicting the separation efficiency of hydrocyclones

A comprehensive insight into the application of machine learning approaches in predicting the separation efficiency of hydrocyclones

Hydrocyclone separation performance influenced by feeding solid concentration and correcting separation size

Operation parameters restrict the performance of hydrocyclone in offshore platforms. Based on the computational fluid dynamics (CFD) software Fluent and the similarity parameter criterion experiment, the numerical simulation of the separation flow field and separation efficiency of hydrocyclone at different feed solid concentration was carried out, taking short circuit flow into account, a new correcting separation size equation was derived according to the locus of zero vertical velocity (LZVV) method. The results shown that when the feed solid concentration was more than 40%, the peak value of tangential velocity decreased and the increasing amplitude of underflow pressure drop will decrease compared with the increasing amplitude of overflow pressure drop, the region with the highest turbulence intensity increased when the concentration was more than 40%. The total separation efficiency and the feed solid concentration showed a positive correlation at 0 ~ 40%, and the increase in total separation efficiency was the smallest when it was higher than 40%, with a value of 0.63%. There was a large difference between the values of d50c* and d50c while the feed solid concentration was 50%. From the above results, it could be concluded that the optimum feed solid concentration ranges were 0 ~ 40%. The new correcting separation size equation could be used in the range of 0 ~ 40%. This study could have certain guiding significance for the field application of the offshore platform desanding hydrocyclone.

Effect of inner wall configurations on the separation efficiency of hydrocyclone

The cyclone separator is widely used for separating liquid-gas as well as particle-laden flow through the vortex separation phenomenon. This is a simple principle with wide temperature and pressure range, so it can be used in various industrial fields. So far, many studies have dealt with the case where there is no groove on the inner wall of the hydrocyclone. In this study, the flow characteristics and the particle separation efficiency of the cyclone separator were investigated by changing the inner wall configuration through numerical analysis. The geometry was designed by changing the wall configuration after referring to previous research. The change of wall was ribbing (convex) and slotting (concave) with a helical pattern. The helical parameters were changed, and their results were compared with each other. The working fluid is water, and the solid is an asphalt that was assumed to be spherical. Numerical analysis was performed using ANSYS CFX ver. 18.1. The Reynolds stress turbulence model (RSM) was used, which is suitable for the simulation of swirling turbulent and vorticial flows. The results of this study suggest that the optimal shape of wall surface will improve the fine particle separation technique of the cyclone separator.

Hydrocyclone Separation Efficiency Modeled by Flow Resistances and Droplet Trajectories

The growing demand to optimize the deoiling performance for offshore oil & gas gives the incentive to improve existing control solutions by means of model-based control solutions. This paper proposes a separation efficiency grey-box model of a deoiling hydrocyclone. Grey-box modeling of deoiling hydrocyclones aims to combine knowledge from fluid dynamics with the data-driven parameter estimation to yield better accuracy than black-box derived models while keeping the computational load much lower than CFD-simulations. The model has to be reasonably accurate in all likely operating conditions and be computed in real-time, in order to be beneficial for advanced model-based control. The developed grey-box model is based on flow resistance and oil droplet trajectory analysis. The model functionally describes how the valve openings, inflow rates, and PDR set-points affect separation efficiency of the considered generic deoiling hydrocyclone. The results are reasonable and provide a fundamental overview of how the operational conditions affect separation efficiency. The model can be extended to account for changes in the axial velocity distribution, coalescence and breakup of droplets.

Effect of Vortex Finder, Inlet and Body Diameter on Separation Efficiency of Hydrocyclone for Crude Palm Oil Industry

Hydrocyclone is novel optional equipment that can be applied in solid separation for crude palm oil process because of its advantage over the existing technology. Hydrocyclone is a cost-effective, continuous tool which is easy for maintenance. The objective of this research is to investigate the effect of vortex finder, inlet, and body diameter of hydrocyclone on separation efficiency of palm meal from crude palm oil by using PVC resin as the solid phase and biodiesel B5 as the liquid phase. All parameters were simulated using computational fluid dynamic, CFD. In addition, the inlet diameters were tested experimentally. The feed flow rates in both simulation and experiment were varied from 4 - 14 L/min at the constant flow ratio of 0.2. Experimental design was clearly specified. The vortex finder diameters of 3.8, 4.8, and 5.8 mm were also simulated as well as the inlet diameters of 5, 6, and 7 mm. Three sizes of body diameter of 30, 40, and 50 mm were selected as the example sizes. According to the simulation results, the smaller vortex finder, inlet, and body diameter of hydrocyclone revealed the higher separation efficiency.

Liquid-Solid Hydrocyclone Numerical Simulation and Separation Efficiency Analysis

This paper analyses the basic structure and the separation theory of hydrocyclone. Three-dimension spiral flow theory and CFD method was used to simulate the Φ75mm hydrocyclone. The paper focuses on researching the separation efficiency influenced by different inlet velocities, volume fraction values and the particle diameters. Besides, the influence of the thickness of overflow pipe is also considered. Results of numerical simulation shows that with the inlet velocity range from 1 to 5m/s and the particle diameters range from 2 to 5um, the hydrocyclone separation efficiency is increasing. As the volume fraction value increased from 1% to 15%, the separation efficiency descended. Increasing the thickness of overflow pipe can reduce the turbulent kinetic energy of hydrocyclone, which can make the inner flow field more stable and enhance the separation efficiency.

Improvement of separation efficiency and production capacity of a hydrocyclone

The improvement of separation efficiency (SE) and production capacity of a hydrocyclone by introducing a newly-designed structure is a significant challenge when applying Reynolds Averaged Navier–Stokes (RANS) turbulence modeling techniques. This study aims to solve the problem that the high content of fine sands in summer in the Chongqing section of the Yangtze River means that it can not be directly taken as the water source for a heat pump system, and also to reduce the energy consumption of the hydrocyclone through the improvement of its structure design. In this research, the RANS approach was applied to simulate the three-dimensional flow field of the hydrocyclone, a Reynolds stress model (RSM) was introduced and used to make the RANS equation close. In the modeling study of the separation mechanism of the hydrocyclone, the impacts of operating parameters and structure parameters on the hydrocyclone SE were studied using RANS methods based on the commercial software FLUENT. Consequently, a new-style hydrocyclone with inclined inlet and ramp board and central solid rod was designed to enhance the SE according to previous numerical modeling results. Under the conditions of the optimal inlet velocity of 15 m s−1 for the new structure and with a sand volume fraction of 10%, the SE of the new structure can be increased near to 60% for 0.004 mm sand particles, and the overflow production capacity can be enhanced to 20 m3 h−1. These data are required both for evaluating the potential use of the hydrocyclone for the separation of sands from water and for studying the new structure which may be important in practical applications to reduce energy consumption, and these comparisons will assist hydrocyclone designers in choosing appropriate turbulence models and structures, and benefit future modeling research.

Developing a new approach for evaluating a de-oiling hydrocyclone efficiency

In this study, a new mathematical approach for evaluating of a de-oiling hydrocyclone efficiency has been developed. This new model uses the flow pattern of disperse phase and the boundary layer separation theory. In the present model unlike the other existing models, it is assumed that the droplet concentration in the radial direction is not uniform within the hydrocyclone. The hydrocyclone separation efficiency is calculated considering the droplet size distribution of the feed and the boundary layer thickness. The present approach considers the effects of droplet load, hydrocyclone geometry, mean droplet size and flow rate on the efficiency. The model is validated by comparison of the calculated separation efficiency with several previous experimental studies.

Experimental Study on Inlet Structure of the Rod Pump with Down-Hole Oil-Water Hydrocyclone

For the problem of high water cut oil producing well, the technology which the oil-water is separated and injected to down hole can reduce cost price. The down-hole oil-water separation system is composed of double fluid flow pump, oil-water hydrocyclone and oil lift pump. This system runs well on site. Experimental study found that the average separation efficiency of hydrocyclone with rectangular section tangent inlet and flow deflector can reach 99.4%, what's more, the average reduction rate of separation efficiency is only 0.25% in continuous flow and it decreases slowly with the ratio of split ratio divided by oil content increasing. Compared with Archimedes spiral inlet, the former's manufacture technology is simpler and suitable to the rod pump's down-hole oil-water separation system.

CFD Simulation of Inlet Design Effect on Deoiling Hydrocyclone Separation Efficiency

AbstractAn Eulerian‐Eulerian three‐dimensional CFD model was developed to study the effect of different inlet designs on deoiling hydrocyclone separation efficiency. Reynolds averaged Navier Stokes and continuity equations were applied to solve steady turbulent flow through the cyclone with the Reynolds stress model. In addition, the modified drag correlation for liquid‐liquid emulsion with respect to the Reynolds number range and viscosity ratio of two phases was used and the simulation results were compared with those predicted by the Schiller‐Naumann correlation. Pressure profile, tangential and axial velocities and separation efficiency of the deoiling hydrocyclone were calculated for four different inlet designs and compared with the standard design. The simulation results for the standard design demonstrate an acceptable agreement with reported experimental data. The results show that all new four inlet designs offer higher efficiencies compared to the standard design. The difference between the efficiency of the LLHC, of the new inlets and the standard design can be improved by increasing the inlet velocity. Furthermore, the simulations show that the separation efficiency can be improved by about 10 % when using a helical form of inlet.

Experimental study on the separation performance of air-injected de-oil hydrocyclones

The developing status and separating principle of de-oil hydrocyclones are first simply introduced. The ways to enhance the hydrocyclone's separation efficiency are described based on theoretical analysis. One of the ways is to inject air into the hydrocyclones so as to combine them with oil to form oil–gas compound bodies, and then increase the de-oil efficiency. By means of injecting air into the hydrocyclone, a new type of hydrocyclone, i.e. air-injected de-oil hydrocyclone (AIDOH), was developed. The basic separation principle of the AIDOH, prototype structure, the experimental technical process and facilities are introduced. Laboratory experiments were carried out. The effects of different geometric parameters, including the vortex finder diameter, and the length, the micro-pore diameter, and different operating conditions, such as flowrate, split ratio, gas–liquid ratio, and especially the air-injecting position, were studied. It was also found that the best injecting part is at the fine cone segment. Further experimental studies were continued to confirm the detailed part in the fine cone segment, which included one-third segment and two-thirds segment. Results show that the best air-injecting part is the first one-third of the fine cone segment. Research indicates that the AIDOH has satisfied the separation effect.

Experimental Study of a New Hydrocyclone for Multi-Density Particles Separation

A new structure of hydrocyclone is designed to meet the demand of separating particles heavier or lighter than water simultaneously. Based on the conventional hydrocyclone, the structural modifications with a section in the middle and a volute chamber on the top of the hydrocyclone to accumulate the separated low density particles. Some factors that influence the separation efficiency of hydrocyclone were investigated in this paper. For the heavy phase, those influencing factors included the inlet flow rate and underflow split ratio. For the light one, different outlets for discharging the light phase were taken into account. The results show that there exists an optimum inlet flow rate for a series of underflow split ratios. The top outlet for separating light phase particles is better than the side outlet's.

Experimental study of a hydrocyclone under cyclic flow conditions for fine particle separation

The difficulty in separating fine particles is described in this paper. The basic separating principle of hydrocyclones and the cyclic experimental research facilities are also introduced. Based on a solid–liquid hydrocyclone used for separating fine particles, the effect of the cyclic flow conditions on hydrocyclone's performance is studied. Effects of the cyclic period ratio, cyclic flowrate amplitude ratio, Reynolds number, gas liquid ratio, and the cyclical signal type on the hydrocyclone's fine particle separation performance, with emphasis on the relative overflow purifying rate, are all studied in detail. The results show that the separation efficiency of the hydrocyclone operating under cyclic flow conditions can be higher than that in steady conditions when the cyclic period ratio is about 0.68 and the cyclic flowrate amplitude ratio is around 2%. The rectangular wave seems to be the best cyclic signal for enhancing the hydrocyclone's separation efficiency.

A Numerical Simulation of Hydrocyclones

A numerical method is presented for the calculation of the three-dimensional flow and separation efficiency for particles with low concentrations in a hydrocyclone. Multi-block curvilinear grids in the frame of a cylindrical coordinate system are used to represent accurately the hydrocyclone geometry. Turbulence is represented by a modified k — ɛ model which adds a curvature correction term with a single empirical constant in the dissipation equation. Both three- and two-dimensional axisymmetric computations are carried out and are compared with experimental data. It is shown that the standard k — ɛ model can produce large errors which result in incorrect predictions of the flow patterns. The three-dimensional calculations using the modified k — ɛ model produce results in good agreement with experimental data. The two-dimensional axisymmetric calculations can predict approximate flow patterns, but are inadequate to predict the separation efficiency of hydrocyclones. To analyse the separation efficiency, a three-dimensional model, as developed in the present study, is required.

Influence of feed solids concentration on the performance of hydrocyclones

AbstractEven though the influence of solids concentration in the feed on the separation efficiency of hydrocyclones has long been recognized, a systematic research on the change in pressure drop across the hydrocyclone and the latter's separation characteristics has thus far been lacking. If all other operating parameters are kept constant, an increase in feed concentration generally leads to a coarser cut size, reduced sharpness of separation and a rise in pressure drop. Apart from the particles hindering one another's radial motion, the limited capacity of the apex valve and the changes in the flow field within the hydrocyclone cause additional particles to be entrained by the overflow. The flow ratio thus becomes an additional parameter in determining the cyclone efficiency. A theoretical model, which takes these effects into account, has been developed and successfully tested against experimental data.