scholarly journals A Downhole Hydrocyclone for the Recovery of Natural Gas Hydrates and Desanding: The CFD Simulation of the Flow Field and Separation Performance

Energies ◽  
2019 ◽  
Vol 12 (17) ◽  
pp. 3257
Author(s):  
Shunzuo Qiu ◽  
Guorong Wang ◽  
Leizhen Wang ◽  
Xing Fang
Keyword(s):  
Flow Field ◽  
Removal Efficiency ◽  
Separation Efficiency ◽  
Solid Phase ◽  
Short Circuit ◽  
Tangential Velocity ◽  
Separation Performance ◽  
Volume Distribution ◽  
Recovery Efficiency ◽  
And Performance

The application of a hydrocyclone to recycle NGH and desand during NGH exploitation is a novel idea. The flow field and performance of this hydrocyclone is in the frontier of the research in this field and is unclear so far. This research aimed to reveal the flow field characteristics and performance of NGH downhole hydrocyclones. In this paper, flow field, solid phase particle volume distribution and separation efficiency were investigated according to the two objectives of NGH recovery efficiency and sand removal efficiency with different inlet velocities by computational fluid simulations (CFD)-FLUENT software. The results show that the short circuit flow contributed to the recovery of NGH. Axial velocity is a decisive factor in balancing the two objectives of NGH recovery efficiency and sand removal efficiency. In addition, the same as those in traditional hydrocyclones, the static pressure, tangential velocity and turbulence intensity play key roles in separation performance, hydrocyclone performance can be improved by increasing the inlet velocity. On the other hand, most separation efficiencies were greater than 80%, when the particle size was larger than 15 µm, and the differential pressure was less than 0.6 MPa. Therefore, all the above results confirm that hydrocyclone has good performance in NGH exploitation, and the basis of its structural design and optimization are provided.

Numerical Simulation of Gas Flow Field in Gas-Liquid Hydrocyclone Separator

2011 ◽  
Vol 109 ◽  
pp. 509-516
Author(s):  
Xiang Hong Jin ◽  
Feng Shuang Han ◽  
Jin Liang Zhang ◽  
Hui Huang ◽  
Xin Wen Liu
Keyword(s):  
Flow Field ◽  
Gas Flow ◽  
Separation Efficiency ◽  
Short Circuit ◽  
Tangential Velocity ◽  
Flow Distribution ◽  
Mouth Area ◽  
Exhaust Pipe ◽  
Outlet Angle ◽  
Gas Flow Field

The gas flow field in hydrocyclone separator was numerically simulated by applying RSM turbulence model, and the gas flow velocity distribution and stress distribution were calculated. According to the characteristics of gas flow distribution within the separator, it is found that: (1) the rotating strength of gas flow is related to the outlet angle of guide blade, the greater the outlet angle, the smaller the tangential velocity; (2) the obvious short circuit flow distribution under the exhaust pipe mouth area is easy to carry droplets and roll them out, causing a decrease in separation efficiency; (3) the high strength of turbulence pulse at mouth area of vent and drainage is easy to break the droplets and decrease their diameter, which affects the separation efficiency. The above research results lay the foundation for the structure optimization and the improvement of separation properties of axial guide vane cyclone gas-liquid separator.

scholarly journals Separation of Radionuclides from a Rare Earth-Containing Solution by Zeolite Adsorption

Minerals ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 20
Author(s):  
Deniz Talan ◽  
Qingqing Huang
Keyword(s):  
Rare Earth ◽  
Rare Earths ◽  
Contact Time ◽  
Separation Efficiency ◽  
Ph Value ◽  
Solid Phase ◽  
Separation Performance ◽  
Solution Ph ◽  
Zeolite Sample ◽  
Alternative Sources

The increasing industrial demand for rare earths requires new or alternative sources to be found. Within this context, there have been studies validating the technical feasibility of coal and coal byproducts as alternative sources for rare earth elements. Nonetheless, radioactive materials, such as thorium and uranium, are frequently seen in the rare earths’ mineralization, and causes environmental and health concerns. Consequently, there exists an urgent need to remove these radionuclides in order to produce high purity rare earths to diversify the supply chain, as well as maintain an environmentally-favorable extraction process for the surroundings. In this study, an experimental design was generated to examine the effect of zeolite particle size, feed solution pH, zeolite amount, and contact time of solid and aqueous phases on the removal of thorium and uranium from the solution. The best separation performance was achieved using 2.50 g of 12-µm zeolite sample at a pH value of 3 with a contact time of 2 h. Under these conditions, the adsorption recovery of rare earths, thorium, and uranium into the solid phase was found to be 20.43 wt%, 99.20 wt%, and 89.60 wt%, respectively. The Freundlich adsorption isotherm was determined to be the best-fit model, and the adsorption mechanism of rare earths and thorium was identified as multilayer physisorption. Further, the separation efficiency was assessed using the response surface methodology based on the development of a statistically significant model.

scholarly journals Influence of Vortex Finder Structure on Separation Performance of Double-Overflow Three-Product Hydrocyclones

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 79
Author(s):  
Yuekan Zhang ◽  
Jiangbo Ge ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Junru Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Experimental Research ◽  
Separation Efficiency ◽  
Structural Parameters ◽  
Separation Performance ◽  
Insertion Depth ◽  
Flow Field Characteristics ◽  
Vortex Finder ◽  
Fine Classification

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.

scholarly journals Effects of Reservoir Parameters on Separation Behaviors of the Spiral Separator for Purifying Natural Gas Hydrate

Energies ◽  
2020 ◽  
Vol 13 (20) ◽  
pp. 5346
Author(s):  
Shunzuo Qiu ◽  
Guorong Wang
Keyword(s):  
Particle Size ◽  
Natural Gas ◽  
Removal Efficiency ◽  
Flow Rate ◽  
Gas Hydrate ◽  
Volume Fraction ◽  
Differential Pressure ◽  
Separation Performance ◽  
Recovery Efficiency ◽  
Natural Gas Hydrate

The spiral separator is an important tool for desanding in natural gas hydrate production, and the change of hydrate reservoir parameters has a great impact on spiral separator behavior. Mastering the influence law is helpful to improve the separation performance. Until now, there was still no detailed analysis of the effect mechanism between reservoir parameters and spiral separator behavior. In this paper, a downhole spiral separator was designed. Then, the effects of reservoir parameters (particle size, hydrate, volume fraction, and sand volume fraction) on separation performance (discrete phase distribution, separation efficiency, and differential pressure) with different flow rates were investigated by numerical simulation method Fluent 18.0. The results show that effects degree of reservoir parameters is in order from large to small: sand phase volume fraction, particle size, hydrate volume fraction. As the particle size increases, the separation performance is improved. When the sand volume fraction increases, the natural gas hydrate (NGH) recovery efficiency and differential pressure both increase, but the sand removal efficiency decreases. When the hydrate fraction increases, the separation performance change law is opposite to that when the sand volume fraction increases. In addition, with increasing the flow rate, the efficiency and differential pressure increase. Therefore, reservoir saturation and porosity can balance NGH recovery efficiency and sand removal efficiency. Furthermore, the spiral separator has good performance under the change of reservoir parameters. The performance of the NGH spiral separator can be also maintained by increasing the flow rate.

Numerical Simulation of Double Inlet Cylinder Cyclone Using CFD

2013 ◽  
Vol 275-277 ◽  
pp. 558-561
Author(s):  
Xiao Ming Yuan ◽  
Hui Jun Zhao ◽  
Jing Yi Qu
Keyword(s):  
Flow Field ◽  
Volume Fraction ◽  
Separation Efficiency ◽  
Separation Performance ◽  
Two Phase ◽  
Phase Volume Fraction ◽  
Fluid Field ◽  
Cylindrical Cyclone ◽  
Discrete Phase ◽  
New Type

Designed a new type of double inlet cylindrical cyclone. For search the separation performance in a cylindrical cyclone. By use of CFD，applied the RSM turbulence model and Euler two-phase flow method and ASM which to simulate separation process and flow field within a double inlet cylindrical cyclone. Then compared with the single inlet cyclone，obtained velocity distribution. Analyzed the differences of discrete phase volume fraction between different viscosity. The results show that the new-style cyclone caught more stable fluid field and higher separation efficiency. And when the viscosity is about 0.75 kg/m•s， the separation efficiency and stability of the oil core is higher. Preliminary flow field law is shown up.

CFD Study of Hydrodynamics and Separation Performance of a Novel Crossflow Filtration Hydrocyclone (CFFH)

2014 ◽  
Author(s):  
Abdul Motin ◽  
Volodymyr V. Tarabara ◽  
André Bénard
Keyword(s):  
Reynolds Number ◽  
Flow Field ◽  
Separation Efficiency ◽  
Cross Flow ◽  
Scale Model ◽  
Navier Stokes ◽  
Dispersed Phase ◽  
Separation Performance ◽  
Porous Filter ◽  
Discrete Phase

This research addresses various hydrodynamic aspects and the separation performance of a novel cross-flow filtration hydrocyclone (CFFH) using computational fluid dynamics. A CFFH is a device that combines the desirable attributes of a cross-flow filter and a vortex separator into one unit to separate oil from water. The velocity and pressure fields within the CFFH are estimated by numerically solving the filtered Navier-Stokes equations (by using a Large Eddy Simulation (LES) approach). The Lagrangian approach is employed for investigating the trajectories of dispersed droplets based on a stochastic tracking method called the Discrete Phase Model (DPM). The mixture theory with the Algebraic Slip Model (ASM) is also used to compute the dispersed phase fluid mechanics and for comparing with results obtained from the DPM. In addition, a comparison between the statistically steady state results obtained by the LES with the Wall Adaptive Local Eddy-Viscosity (WALE) subgrid scale model and the Reynolds Average Navier-Stokes (RANS) closed with the Reynolds Stress Model (RSM) is performed for evaluating their capabilities with regards to the flow field within the CFFH and the impact of the filter medium. Effects of the Reynolds number, the permeability of the porous filter, and droplet size on the internal hydrodynamics and separation performance of the CFFH are investigated. Results indicate that for low feed concentration of the dispersed phase, separation efficiency obtained based on multiphase and discrete phase simulations is almost the same. Higher Reynolds number flow simulations exhibit an unstable core and thereby numerous recirculation zones in the flow field are observed. Improved separation efficiency is observed at a lower Reynolds number and for a lower permeability of the porous filter.

CFD modelling of flow field and particle tracking in a hydrodynamic stormwater separator

2010 ◽  
Vol 62 (10) ◽  
pp. 2381-2388 ◽  
Author(s):  
J. H. Lee ◽  
K. W. Bang ◽  
C. S. Choi ◽  
H. S. Lim
Keyword(s):  
Flow Field ◽  
Removal Efficiency ◽  
Particle Tracking ◽  
Best Management Practices ◽  
Management Practices ◽  
Separation Efficiency ◽  
Pollutant Removal ◽  
Solid Particles ◽  
Storm Water ◽  
Velocity Flow

The best management practices (BMPs) for control of urban stormwater pollution are evaluated to remove solid particles containing various pollutants. Currently, most storm runoff treatment devices using primary pollutant removal mechanism are applied to storm water since most pollutants in runoff are associated with the solid particulates. A hydrodynamic separator is a storm water treatment device using centrifugal motion which separates solids pollution from runoff. In this study, the velocity flow field and particle tracking of hydrodynamic separator were investigated using anthracite as a computational fluid dynamics (CFD) model particle. The Fluent 6.3.26 CFD program was used to predict the solid particles removal efficiency for various parameters such as particle size, surface loading rate, and the ratio of underflow to overflow. The velocity flow field in a hydrodynamic stormwater separator (HDS) has been simulated using CFD RNG κ-ɛ model. Modeling results for the removal efficiency of HDS were similar with the results obtained from experimental measurements of laboratory scale HDS. These results showed that the simulated velocity field was useful to interpret the behavior of flow in the hydrodynamic separator. The results obtained from particle tracking can be applied to predict the separation efficiency.

Study on Separation Performance of Gas-Liquid Cyclone Separator with Pulsating Feeds

2021 ◽  
Vol 14 ◽  
Author(s):  
Guangrong Lu ◽  
Yongjun Hou ◽  
Xianjin Wu ◽  
Hang Wu ◽  
Rui Jiang ◽  
...  
Keyword(s):  
Flow Field ◽  
Separation Efficiency ◽  
Drilling Fluid ◽  
Structural Parameters ◽  
Stable State ◽  
Field Analysis ◽  
Separation Performance ◽  
Liquid Separation ◽  
Flow Field Characteristics ◽  
Feed Condition

Background: In recent years, a kind of drilling method of Solid-Liquid separation combined with pulsating vacuum formed by vibrating screen and compressed air injection has emerged in oil drilling, which greatly improves the gas, solid and liquid separation ability of the drilling fluid vibration screen. Objective: Based on the above ideas, a kind of hydrocyclone used for gas-liquid separation with the pulsating feed boundary was proposed. The separation performance of gas-liquid hydrocyclone may change greatly due to the mixed pulsation of the gas-liquid fluid transported by the jet pump. Therefore, the flow characteristics of the pulsating feed hydrocyclone need to be analyzed and explored to provide basic data for further improvement of structure. Methods: The development status of cyclone separators are summarized through related literatures and patents investigation. The Computational Fluid Dynamics (CFD) software ANSYS Fluent 2019 R3 is used to analyze the flow field characteristics and optimize the parameters of the hydrocyclone with stable feed. Then, programming by the User-Define-Function (UDF) of Fluent is used to simulate the flow field of the separator under the condition of pulsating feed, meanwhile, the flow field analysis and parameter optimization are carried out accordingly. Results: The optimal parameters in stable state and pulsed state are obtained through the analysis of efficiency curve. The results show that the flow field can be stabilized in the pulsating feed state, and the sinusoidal pulsing with a frequency of 0.4Hz is used to achieve the highest separation efficiency, reaching 85.5%. Conclusion: The separators with pulsating feed and stable feed have similar flow field characteristics, and the optimal structural parameters under pulsating feed are obtained. Compared with the stable feed condition, the pulsating feed condition can connect multiple cyclone separators, which can separate more drilling fluid in unit time, and the work efficiency could be improved. It has a strong practicability, which provides an important basis for the structure optimization in future.

Dry beneficiation of +0.5mm-5.6mm South African coal using an air dense medium fluidization bed

2021 ◽  
Author(s):  
Elmarie Sunette Diedericks ◽  
Marco Le Roux ◽  
Quentin Peter Campbell
Keyword(s):  
Particle Size ◽  
Fluidized Bed ◽  
Separation Efficiency ◽  
Solid Phase ◽  
Poor Performance ◽  
Operating Conditions ◽  
High Mass ◽  
Dense Medium ◽  
Separation Performance ◽  
Coal Particles

Abstract The separation performance of solid phase bed material, at various particle size ranges, in an air dense medium fluidized bed (ADMFB), were evaluated during this study. The coal particles were separated into +0.5mm-1mm, +1mm-2mm, +2mm-2.8mm, +2.8mm-4mm, +4mm-4.75mm and +4.75mm-5.6mm particle size ranges and fed to the fluidized bed in these fractions. Along with the six coal particle size ranges, three dense media to coal ratios and the addition of vibration was tested to identify the best operating conditions. Adequate results were obtained for larger particle size ranges down to and including +2.0mm-2.8mm coal particles, after which the separation performance decreased significantly. Density stratification was irregular and not obvious for coal particles below 2.0mm and maintaining a consistent fluidization state also proved to be challenging, especially when dense medium was added. The coal particles separated vertically along the bed height because of differences in particle and bed density, while particle size proved to have a notable influence on the degree of separation. An air fluidization velocity of between 1.1 to 1.4Umf was shown as the best performing velocity, which yielded the maximum ash differential between the top and bottom layers of the bed for all the particle size ranges tested. For +2.0mm-5.6mm coal particles, low cumulative ash yields were obtained at high mass yields, however the ash yields increased for -2mm coal. Vibration and dense medium have, in some cases, enhanced the separation efficiency of the ADMFB. The -2.0mm particles experienced stronger particle-particle interactions as well as elevated levels of bubbling and back mixing than that of the +2.0mm particles, which explains the poor performance of the small particle sizes.

Study of Operating Parameters’ Impact on Separation Performance of Cyclone Separator

2011 ◽  
Vol 422 ◽  
pp. 794-798
Author(s):  
Xue Ping Wang ◽  
Ying Zhang ◽  
Ju Guang Xue ◽  
Zhen Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Flow Velocity ◽  
Turbulence Model ◽  
Separation Efficiency ◽  
Operating Parameters ◽  
Separation Performance ◽  
Cyclone Separator ◽  
High Concentration ◽  
Secondary Particles

The numerical simulation can be obtained by taking advantage of turbulence model of Fluent to study the gas-solid flow field of cyclone separator. The pressure of the cyclone drops increases with the enhancement of the inlet flow velocity, and the increase amplitude can become larger and larger. The separation efficiency of the cyclone enhances gradually as the increase of the flow. The increase amplitude of small and secondary particles is much lager compared with the increase amplitude of big ones. The overall separation efficiency can strengthen gradually with increasing of particles concentration as well as the each part’s efficiency. But the separation efficiency will stay in stable level when the concentration reaches a certain value with the big particles in the low concentration and small ones in a relatively high concentration.

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