Particle Separation Process Research Articles

Numerical investigation on the performance and flow pattern of two novel innovative designs of four-inlet cyclone separator

In solid particle separation process, cyclone separators are commonly used due to their simplicity and low-cost manufacture. A reference design S1 and two novel designs C4, N4 of four-inlet cyclone separator have been investigated computationally using the Reynolds Stress Model for turbulent flow and the Discrete Phase Model for tracking the particles. The numerical model has been validated and confirmed to be a reasonable good candidate for the investigation. The results show that, the design S1 provides the lowest average Euler number (4.415) and the design C4 provides the smallest average cut-off diameter (1.399 μm). As comparing the performances using weighted sum method, both two novel designs provide the better performance than the reference design S1. The innovative design N4 delivers the best performance which is 1 % and 0.1 % better in performance than S1 and C4, respectively.

Recirculation Flow of Nanofluid Through Periodic Nanotube with Hexagonal Cross-Section

In this paper, we have investigated the recirculation flow of a nanofluid in the developed flow zones of an infinite periodic nanotube with a hexagonal cross-section. A numerical analysis is commenced to identify the existence of single and double recirculation zones for various geometric parameters. The boundary element method (BEM) has been formulated for an unbound interim nanotube for solving the governing equations. We have developed the codes for the BEM method in FORTRAN 90, and the graphs have been plotted in MATLAB 2016. We have various geometric parameters to inaugurate circumstances for the onset of recirculation. We have found recirculation flow through this type of periodic tube for a set of geometric parameters such as amplitude, wavelength and throat radius etc. Firstly recirculation flow in the expansion region of the nanotube is prophesied to arrive beyond a critical amplitude and second order recirculation zone is also predicted for still higher amplitudes. The recirculation flow has great importance in the application, for example, it can be used in the particle separation process.

Continuous elasto-inertial separation of microparticles using a co-flowing Newtonian-viscoelastic fluid system

A new method for continuous separation of microparticles in viscoelastic fluid is reported. A series of sharp corners were fabricated at one side of a microchannel, which induced the curved streamline and the asymmetric distribution of the elastic force. The Newtonian sheath flow was utilized to squeeze microparticles to the side wall with sharp corners at the inlet. Particles were subjected to inertial forces, elastic force and viscous drag force, all of which pointed to the straight wall side. Stronger forces were exerted on larger particles, leading to size-dependent migration of particles across the interface between the Newtonian and the viscoelastic fluids. The influence of the flow rate ratio on the particle separation was also studied. The results show that the sharp corners and the co-flowing fluid system significantly enhanced particle lateral migration, achieving complete particle separation at a low flow rate and in a short channel length. The particle separation efficiency was further increased at a higher flow rate ratio (sheath flow/sample flow). With a simple structure and small footprint, this device has great potential to be used in a variety of particle separation processes for lab-on-a-chip applications.

Vibrational dynamics of paramagnetic particles and processes of separation of granular materials

In this paper we consider the problem of dry magnetic separation simulations for granular material. Magnetic separator for dry magnetic enrichment of paramagnetic particles, in which the vibration effect is used as a disaggregation factor, is considered. Granular material is subjected to intense vibration, transferring it into the state of a “granular gas” before separation. A closed system of equations describing motion of paramagnetic particles (subjected to the magnetic force field) in the “granular gas” of non-magnetic particles is obtained. Analytical calculations give relatively simple equations that provide qualitative assessment of the paramagnetic particles separation process. The corresponding insights into the process facilitate numerical modeling of magnetic separation and can be also of useful for calculating the performance of magnetic separators in dry separation conditions with vibratory material feed into the operating area.

Heat-Assisted Batch Settling of Mineral Suspensions in Inclined Containers

In mineral processing, the common requirement for progressively finer milling due to the decreasing of ore grades implies the need for more challenging water recovery conditions in thickeners. Several mining operations exist in arid areas, where water recovery becomes critical. The present paper explores the process of particle separation in batch inclined settlers where the downward facing wall is subject to heating. To this purpose, two-dimensional numerical simulations using a mixture model have been run for a number of combinations of temperature jumps at the downward facing fall, particle diameters, and concentrations. Results show that, for particle sizes on the order of 10 µm, heating has a significant effect on the particle settling velocity at the bottom, but it also promotes particle resuspension, affecting the particle concentration at the supernatant layer. The initial concentration also affects settling: for the concentration range tested (8%–15% by volume), when re-normalized by the average concentration, particle accumulation rates at the bottom were found to be lower for higher average concentrations, thus suggesting that the separation process is more efficient at lower concentrations.

Comparing fine particulate iron hydroxide adsorbents for the removal of phosphate in a hybrid adsorption/ultrafiltration system

The use of micro-sized iron hydroxide adsorbents in mixed reactors is a promising technique for the removal of inorganic contaminants from wastewater within minutes of contact time. This study focusses on phosphate adsorption onto fine fraction granular ferric hydroxide (µGFH) and iron oxy(hydr)oxide agglomerates (IOAs) in a reactor with submerged ultrafiltration (UF) membrane. The performance of the hybrid adsorption/UF membrane system was evaluated for various adsorbents and phosphate concentrations, residence times and concentrations of co-existing ions. The membrane was not fouled at the experimental conditions used (up to 6.3 g/L adsorbent).Phosphate loadings of 20 and 60 mg P/g Fe (36.1 and 108.3 mol P/mol Fe) were reached for µGFH and IOAs, respectively (C0(P) = 4.5 mg/L, deionized water at pH 8, C(Fe) = 0.6 g/L). A shortened residence time of 15 min in the reactor led to a decrease in final loading of 6 mg/g compared to 30 min residence time (54 mg/g compared to 60 mg/g). An extension to 60 min did not result in higher loadings. An increase in adsorbent (IOA) concentration from 0.1 to 0.3 mg/L resulted in an increase of phosphate removal (27 to 35%). Simultaneously, loadings decreased from 50 to 35 mg/g. The application of the developed process for the treatment of artificial secondary effluent resulted in an increase of 87 and 60% in treated volumes until breakthrough (50%) for µGFH and IOAs, respectively, compared to deionized water. Thus, the combined process of adsorption and particle separation using a submerged membrane can be well adjusted according to water composition, initial pollutant concentrations and desired removals.

Effect of Magnetic Field in Magnetic Separation Column on Particle Separation Process Based on Numerical Simulation

Effect of Magnetic Field in Magnetic Separation Column on Particle Separation Process Based on Numerical Simulation

Analysis of dynamic characteristics of two-component granular mixture segregation in thin shear cell

Particle separation is important in industrial production. The granular powder exhibits the property that is like both fluid property and solid property, which makes it difficult to establish a mathematical model to reveal the particle motion mechanism. The fluid property of the granular powder can be partly explained by the classical fluid theory, but the solid property cannot be covered. Theories combining the fluid and solid properties are also used to explain the particle separation phenomenon. However, they are not in consensus about the granular theory to explain the particle separation mechanism. Friction dissipation, which represents the particle pairwise damp interactions, greatly influences the particle separation process. In order to understand the particle separation mechanism and the effect of friction coefficient on the particle motion, a three-dimensional discrete element model is used to simulate the separation of three-dimensional spherical binary particles in a cylindrical groove （shear cell）in this paper. Initially, the large particle is placed at the bottom and the other small particles pile into the groove. The shear flow of the particles is established by rotating the bottom plate of the groove. The large particles gradually jump to the top of the groove under the shearing action. The effect of particle friction coefficient on the separation is studied. Focusing on the characteristics of kinematics and dynamics in the jumping process of large particle, the influence of the friction coefficient on the trajectory, velocity and acceleration of particle are quantitatively analyzed. The conclusions are obtained as follows. 1) The process of large particle jumping can be divided into three stages: relaxation stage (the large particle stays at the bottom of the groove), the take-off stage (the large particle rises up), and the equilibrium stage(the large particle moves to the top and stays there). 2) The relaxation time decreases with friction coefficient increasing. 3) The equilibrium height of particles increases with friction coefficient increasing. 4) The amplitude of the force pulsation of the large particle increases with friction coefficient increasing. For the behavior analysis of the ascending motion of the large particle, we propose a neighborhood analysis method and define a floating factor. The ratio of the number of small particles arranged in the upper to that in the lower adjacent space of the large particle is defined as the buoyancy factor. It is found that the buoyancy factor drops sharply at the jumping point of the large particle, forming the opportunity for the large particle jumping. It is revealed that the take-off of the large particle is the result of both the high-frequency characteristics of force fluctuation and the steep drop of buoyancy factor. The rising motion of the big particle is determined by the force and the surrounding space.

An experimental investigation into the particle classification capability of a novel cyclone separator

Cyclone separators are widely used for dedusting of particle-laden flows in many branches of industry. A new cyclone containing several collectors was designed in modular structure to investigate the capability of particle classification of the cyclone during particle separation process. The particulate air was supplied into the cyclone in a test bench operated in suction mode under ambient temperature and atmospheric pressure conditions. The flow rate and pressure drop were measured, and the particles accumulated in the dust collectors were weighed and analyzed for each test. The changes in the overall collection efficiency and pressure drop with the flow rate were obtained. In order to determine the classification characteristics of the cyclone, the experiments were repeated in different configurations obtained by changing the locations and number of the collectors. The mean particle diameter and particle size distribution of the dust collected in each collector were acquired. Analysis of the results shows that the designed cyclone is capable of classification incoming particles into 2, 3 or 4 classes in the cyclone according to particle size. Classification performance of the configurations and influences of flow rate on this performance were also investigated. A distinct and satisfactory classification was obtained in the configuration with three collectors.

Effect of discretization method of a computational domain on particle separation in a cyclone separator

This paper reports the results of a study into the effect of the selection of a method of discretization of the computational domain on the solid particles separation process in a cyclone separator. The selection of an optimum discretization method to be implemented in a computational domain forms a particularly important task during analysis using CFD. The process of discretization largely affects the precision of the results gained using the CFD models as well as independence of the results on the mesh density and duration of the computations. The comparative analysis was performed on the basis of the results of experimental and numerical research with regard to the separation efficiency and pressure drop. It was observed that the computational domains generated on the basis of hexagonal meshes provide the best conformity of the results in terms of the separation efficiency, which is the key parameter applied to assess the quality of a cyclone separator.

Internal Recycled Particles Circulation in Vortex Granulator

A theoretical model that describes the internal recycled particles separation process in suspended-layer vortex granulators (SLVG) with a height-variable cross-sectional area is presented. Relationships are derived to determine the recycled particles circulation time in SLVG with a specified configuration. The calculated results are confirmed by experimental studies on an SLVG prototype. The results of the analytical solution of the equations of the mathematical model can be used to design SLVG with an internal recycled particles circulation, which can be organized in various ways, depending on the need for simple recirculation or the presence of additional recycled particles thermal treatment stage during recirculation.

Non-linear optimisation and energy integration of a particles separation–classification process

ABSTRACTThe gas–solid separation has several industrial applications in engineering process. The collection efficiency and the energy consumption are critical variables in particles separation process. In this study, a non-linear programming problem is proposed to maximise the cyclone efficiency in a 34,560.0 ton/year particles separation–classification plant. A new process integration scheme is proposed to energy consumption minimisation. The units included in the model are a powder feeder, a high efficiency cyclone, a bag filter and a blower. Stairmand and Swift’s high efficiency cyclones models are evaluated and compared. Four particulate materials are considered: limestone, dolomite, sawdust and toner. The particles diameters range studied is 0.1–1000 m. Mass and energy balances are solved with an initial solid concentration of 500 g/m. Stairmand’s cyclone proved to be more efficient than Swift for all materials analysed. The highest cyclone efficiency is achieved for sawdust ( 99%). The cyclone separates more than 34,000 ton/year of particles m. The energy integration scheme consumes 43% less energy than the basic one for all cases studied. The proposed optimisation model results a valuable tool for optimal process design, reducing the environment process impact and adaptable to operate at high temperatures values with different materials.

Air Pollutants Minimalization of Pollutant Absorber with Condensation System

Industrial development has implications for pollution, one of it is air pollution. The amount of air pollutants emitted from industrial depend on several factors which are capacity of its fuel, high chimneys and atmospheric stability. To minimize pollutants emitted from industries is created a tool called Pollutant Absorber (PA) with a condensing system. Research & Development with the approach of Design for Production was used as methodology in making PA. To test the function of PA, the simulation had been done by using the data on industrial emissions Cilegon industrial area. The simulation results in 15 years period showed that the PA was able to minimize the pollutant emissions of SO2 by 38% NOx by 37% and dust by 64%. Differences in the absorption of pollutants shows the weakness of particle separation process in the separator. This condition happen because the condensation process is less optimal during the absorption and separation in the separator.

Simulation and experimental research on coarse coal slime particles’ separation in inclined tapered diameter separation bed

A novel inclined tapered diameter separation bed (ITDSB) was designed for the beneficiation of coarse coal slime. Computational fluid dynamics (CFD) coupled with the discrete element method (DEM) was explored to study particle separation and the effect of underscreen water on particle movements over time. Results show that coal particles and gangue particles have disparate movements. Coal particles are drifted by the force of water flow and have the analogous trend of movements as water flow, while gangue particles sink towards the lower part of the bed under the effect of the gravity. Secondary separation was achieved through forcing particles to bounce back into the flow field and benefited from the invention and application of underscreen holes. The three factor orthogonal experiments of separating coarse coal slime (3–0.5 mm) have been performed. The obtained clean coals and tailings were tested and further analyzed with an X‐ray fluorescence spectrometer (XRF) and scanning electron microscope (SEM). XRF and SEM results show that gangue minerals were discarded significantly after the separation. Orthogonal experimental results reveal that with reasonable combination of various levels of factors, the average combustible recovery is approximately 60 %, which shows that the inclined tapered diameter separation bed is efficient equipment for coarse coal slime beneficiation. Secondary separation and the effect of underscreen water were simultaneously verified as efficient methods in particle separation processes.

Separation Process of Fine Coals by Ultrasonic Vibration Gas-Solid Fluidized Bed.

Ultrasonic vibration gas-solid fluidized bed was proposed and introduced to separate fine coals (0.5–0.125 mm fraction). Several technological methods such as XRF, XRD, XPS, and EPMA were used to study the composition of heavy products to evaluate the separation effect. Results show that the ultrasonic vibration force field strengthens the particle separation process based on density when the vibration frequency is 35 kHz and the fluidization number is 1.8. The ash difference between the light and heavy products and the recovery of combustible material obtain the maximum values of 47.30% and 89.59%, respectively. The sulfur content of the heavy product reaches the maximum value of 6.78%. Chemical state analysis of sulfur shows that organic sulfur (-C-S-), sulfate-sulfur (-SO4), and pyrite-sulfur (-S2) are confirmed in the original coal and heavy product. Organic sulfur (-C-S-) is mainly concentrated in the light product, and pyrite-sulfur (-S2) is significantly enriched in the heavy product. The element composition, phase composition, backscatter imagery, and surface distribution of elements for heavy product show concentration of high-density minerals including pyrite, quartz, and kaolinite. Some harmful elements such as F, Pb, and As are also concentrated in the heavy product.

정화 보조지표와 시료 채취 방법 제안을 통한 토양정화검증 제도 개선 연구

In addition to the measurement of the concentration of soil contaminants, the new idea of indicative parameters was proposed to validate the remedial works through the monitoring for the changes of soil characteristics after applying the clean up technologies. The parameters like CFU (colony forming unit), pH and soil texture were recommended as indicative parameters for land farming. In case of soil washing, water content and the particle size distribution of the sludge were recommended as indicative parameters. The sludge is produced through the particle separation process in soil washing and it is usually treated as a waste. The parameters like water content, organic matter content, CEC (cation exchange capacity) and CFU were recommended as indicative parameters for the low temperature thermal desorption method. Besides the indicative parameter, sampling methods in stock pile and the optimal minimum amount of composite soil sample were proposed. The rates of sampling error in regular grid, zigzag, four bearing, random grid methods were 17.3%, 17.6%, 17.2% and 16.5% respectively. The random grid method showed the minimum sampling error among the 4 kinds of sampling methods although the differences in sampling errors were very little. Therefore the random grid method was recommended as an appropriate sampling method in stock pile. It was not possible to propose a value of optimal minimum amount of composite soil sample based on the real analytical data due to the dynamic variation of <TEX>$CV_{fund{\cdot}error}$</TEX>. Instead of this, 355 g of soil was recommended for the optimal minimum amount of composite soil sample under the assumption of ISO 10381-8.

Economic Analysis of an Integrated Annatto Seeds-Sugarcane Biorefinery Using Supercritical CO₂ Extraction as a First Step.

Recently, supercritical fluid extraction (SFE) has been indicated to be utilized as part of a biorefinery, rather than as a stand-alone technology, since besides extracting added value compounds selectively it has been shown to have a positive effect on the downstream processing of biomass. To this extent, this work evaluates economically the encouraging experimental results regarding the use of SFE during annatto seeds valorization. Additionally, other features were discussed such as the benefits of enhancing the bioactive compounds concentration through physical processes and of integrating the proposed annatto seeds biorefinery to a hypothetical sugarcane biorefinery, which produces its essential inputs, e.g., CO2, ethanol, heat and electricity. For this, first, different configurations were modeled and simulated using the commercial simulator Aspen Plus® to determine the mass and energy balances. Next, each configuration was economically assessed using MATLAB. SFE proved to be decisive to the economic feasibility of the proposed annatto seeds-sugarcane biorefinery concept. SFE pretreatment associated with sequential fine particles separation process enabled higher bixin-rich extract production using low-pressure solvent extraction method employing ethanol, meanwhile tocotrienols-rich extract is obtained as a first product. Nevertheless, the economic evaluation showed that increasing tocotrienols-rich extract production has a more pronounced positive impact on the economic viability of the concept.

Acoustic separation of oil droplets, colloidal particles and their mixtures in a microfluidic cell

Here we report direct macroscopic and microscopic observations of acoustic driven separation of dodecane oil droplets in water in the presence and absence of colloidal silica particles suspended in the water phase. The experiments were conducted in a simple rectangular channel glass microfluidic cell in which an ultrasound standing wave pattern was generated at 300KHz frequency. The separation process of both oil droplets and colloidal particles inside the cell was recorded using a high-speed video camera equipped with a macro-objective lens for macroscopic observation or with a high-speed camera attached to an inverted optical microscope for a higher resolution microscopic observation. We characterize the clustering process in the case of emulsion droplets or solid colloidal particles and ultimately demonstrate the emulsion droplets separation from the solid particles in the mixtures based on their different acoustic contrast factors. Finally, we conduct proof of concept experiment to show that the same approach can be used in a continuous fluid flow process.

Computation of Supersonic Branching Flow with Aerosol Particle Separation

Supersonic branching flows are commonly found in industrial processes like the supersonic aerosol particle separation process and the supersonic inlet of combined aeroengines. In this research, we carry out a numerical study on the supersonic branching flow to reveal its features and its effects on aerosol particle separation. It is found that there are four flow regimes and a critical state in the supersonic branching flow in terms of the shock wave positions, which are determined by the backpressures of the two outlets. The gas flow rate ratio and the particle separation ratio are closely related to the flow regimes. There is a steady working zone where the gas flow rate ratio and the particle separation ratio maintain as constant as the two backpressures vary. In swirling flows, there is a drift of the critical state. In the range of particle sizes studied here, the particle motion is not sensitive to the variations of the particle size in the absence of swirl, but it is not the case for swirling flows. Finally, some features of the steady working zone are discussed. This work is a preliminary research into supersonic branching flow and provides a foundation for the design of relevant devices.

A road-map for energy-neutral wastewater treatment plants of the future based on compact technologies (including MBBR)

In the paper concepts for domestic wastewater treatment plants of the future are discussed by the use of a) one flow diagram based on established, compact, proven technologies (i.e. nitrification/denitrification for N-removal in the mainstream) and b) one flow diagram based on emerging, compact technologies (i.e. de-ammonification in the main stream).The latter (b) will give an energyneutral wastewater treatment plant, while this cannot be guaranteed for the first one (a). The example flow diagrams show plant concepts that a) minimize energy consumption by using compact biological and physical/chemical processes combined in an optimal way, for instance by using moving bed biofilm reactor (MBBR) processes for biodegradation and high-rate particle separation processes, and de-ammonification processes for N-removal and b)maximize energy (biogas) production through digestion by using wastewater treatment processes that minimize biodegradation of the sludge (prior to digestion) and pretreatment of the sludge prior to digestion by thermal hydrolysis. The treatment plant of the future should produce a water quality (for instance bathing water quality) that is sufficient for reuse of some kind (toilet flushing, urban use, irrigation etc.). The paper outlines compact water reclamation processes based on ozonation in combination with coagulation as pretreatment before ceramic membrane filtration.