Agitator Blade Research Articles

Variation of Agitator Blades in Continous Settling Tank to Reduce Oil Losses in Oil Refining Process in Palm Palm Factories

Continuou Settling Tank (CST) is one of the units located at the clarification station where the CST works to separate oil and mud based on differences in specific gravity where the lighter density will go up, namely oil, while the heavy type will settle to the bottom, namely mud. The language here is how to make the construction of the agitator transmission in the Continuou Settling Tank (CST) unit and how the agitator blade influences the oil content contained in the sludge in the Continuou Settling Tank (CST) unit. The method is carried out with variations in the number of blades that open 2, 4 and 6 pieces. The specifications of the equipment data obtained are primary data resulting from the design of the Continuou Settling Tank (CST) tool. Based on the blade obtained two results the percentage of oil content of 10.85%. This shows that there is still oil content in the mud. Likewise, the blade that found four pieces was 8.678%. While on the blade that got six pieces, the average percentage of oil was 7.652%. This shows that the blades that have been opened six pieces have met the desired percentage of oil standards.

Design and Frame Strength Evaluation of Salt Washing Unit Capacity 50 Kg/hour

The salt washing unit is part of the salt processing machine. This unit's function is to wash raw salt with brine. This unit has a motor, agitator blade, washing chamber, and frame. The frame structure strength of the salt washing unit needs to be evaluated to ensure safety. This research aims to design the salt washing unit and obtain simulation results of frame structure strength to ensure the safety of the salt washing unit. This research was carried out by simulation to look for stress, strain, and changes in the shape of objects (displacement). The frame strength simulation was carried out using Solidwork software. The salt washing unit with a 50 kg/hour capacity has been designed. It has a cylindrical shape with 990 mm in height and 680 mm in diameter. From the simulation results of strain, it can be concluded that the minimum point is 1.80 × 108 Mpa, and the maximum point is 1.63 × 105 Mpa. From the simulation results of displacement, it can be concluded that the minimum point is 0 mm and the maximum point is 2,296 mm. The maximum stress is 5.254×106 N/m2, and the minimum stress point is 1.803×106 N/m2.

Effect of V on microstructure, wear and corrosion properties in AlCoCrMoVx high entropy alloy coatings by laser cladding

To improve the service life and wear resistance of the agitator blade, AlCoCrMoVx (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0 at.%) high entropy alloy (HEA) coatings were prepared on the 904L-stainless-steel substrate by laser cladding, and the effect of V content on the microstructure, wear and corrosion behavior were investigated. The HEA coatings consist of body-centered cubic (BCC) phase, needle-like σ phase, and irregular black AlN phase. As the V content increases, the σ phase gradually disappears. The trend of microhardness decreases firstly and then increases. AlCoCrMoV1.0 HEA coating has the highest microhardness (942.6 HV0.1). The average friction coefficient of HEA coatings firstly increases and then decreases, but the specific wear rate is the lowest when x = 0.8 (about 0.630 × 10−5 mm3 N−1 m−1). The addition of V improves the corrosion resistance of the coatings, AlCoCrMoV0.8 coating has the lowest Icorr value of 2.74 × 10−5 A cm−2 and the largest impedance radius. In a word, the addition of V in AlCoCrMoVx HEA coatings greatly improves the performance of coatings.

A Novel Compositional Design of [Cr–Fe4Co4Ni4]Cr2.6−xTixMo0.4 High‐Entropy Alloy Coating Based on the Cluster‐Plus‐Glue‐Atom Model and Its Mechanism of Resisting Strong Acid Erosion

To extend the service life of the agitator blade, a series of [Cr–Fe4Co4Ni4]Cr2.6−x Ti x Mo0.4 (x = 0, 0.3, 0.6, and 0.9) high‐entropy alloy (HEA) compositions based on the cluster‐plus‐glue‐atom model is designed, and HEA coatings are deposited on 904L stainless steel using the laser cladding technique. The phase structure, microhardness, wear resistance, corrosion resistance, and erosion properties of the HEA coatings are determined using X‐ray diffractometer, transmission electron microscope, a microhardness tester, a friction and wear tester, an electrochemical workstation, and an erosion testing machine, respectively. The coating's phase structure is made of FCC solid solution. The coatings’ microhardness, wear, corrosion, and erosion resistance gradually improve by adding Ti. In particular, the microhardness of the [Cr–Fe4Co4Ni4]Cr1.7Ti0.9Mo0.4 coating reaches a peak value of 295.11 HV0.2, over 1.5 times that of the 904L stainless steel (190 HV0.2). Its specific wear rate (3.64 mm3 N−1 m−1) is lower than that of the substrate (8.53 mm3 N−1 m−1). The impedance of the [Cr–Fe4Co4Ni4]Cr1.7Ti0.9Mo0.4 coating is roughly 5.3 times of the 904L stainless steel. Simultaneously, the coating's cumulative volume loss rate of erosion–corrosion (0.054 mm3 h−1) is lower than that of the substrate (0.063 mm3 h−1). Consequently, the innovative HEA coating has an impressive overall performance.

ЗАВИСИМОСТЬ ЧАСТОТЫ ВРАЩЕНИЯ ЛОПАСТЕЙ МЕШАЛКИ МОКРОГО ПЫЛЕУЛОВИТЕЛЯ ОТ ПЛОТНОСТИ ЖИДКОСТИ

One of the undesirable factors when grinding grain with hammer crushers is the formation of flour dust, which is fire and explosive, as well as harmful to the health of service personnel. The applied fabric dust collectors ineffectively purify the air coming out of the pneumatic system of the crusher. One of the directions of development of dust collection equipment is the development of wet dust collectors or the improvement of existing ones. The proposed two-stage wet dust collector gives greater efficiency of air purification from dust, which is shown by laboratory studies. One of the factors affecting the quality of cleaning is the speed of rotation of the agitator blade, which varies depending on the concentration of dust in the liquid of the first stage. Not the entire dust-air mixture passes through the upgraded dust collector, but only the part that is redundant. This allows you to increase the life of the dust collector before the next service. The aim of the work is to study the dependence of the rotation speed of the blade of the agitator of the first stage of the dust collector on the density of the liquid. Methods of mathematical modeling of the agitator operation, approximation and regression analysis were used for the research, correlation analysis was performed. Theoretical studies have revealed a hyperbolic dependence of the rotation frequency of the paddle agitator on the density of the colloidal solution, however, experimental data provided other quantitative indicators. To determine the necessary parameters of the equation, the least squares method was used to approximate the experimental data. The calculated data obtained were compared with the experimental ones by the coefficient of determination, and the model was highly adequate, R2 = 0,9705. The presented method of selecting the regression equation shows good convergence with the experiment. The equations derived for a laboratory installation can be converted to an industrial design using the theory of similarity.

Nano-TiC reinforced [Cr–Fe4Co4Ni4]Cr3 high-entropy-alloy composite coating fabricated by laser cladding

The agitator blade made by 904 L stainless steel was subjected to serious corrosion-wear due to its low hardness in phosphoric acid reactors. In this aspect, various nano-TiC reinforced [Cr–Fe4Co4Ni4]Cr3 HEA composite coatings were designed using the cluster-plus-glue-atom model and fabricated on 904 L stainless steel by laser cladding. The phase structure of the composite coatings was composed of FCC solid solution and TiC phase. The microstructure observation detected that tiny TiC particles widely distributed along the inter-dendrites of FCC matrix. Also, the particle dimensions and volumes rapidly enhanced with the addition of TiC. Whereas, excessive TiC contents (≥12.5vol%) led to the generation of microcracks. The TEM results further confirmed that TiC particles did not decompose during laser cladding. With the addition of TiC, the microhardness, wear and corrosion resistance of the composite coatings gradually increased. Especially, the microhardness of [Cr–Fe4Co4Ni4]Cr3-15vol%TiC composite coating reached the peak value of 357.4 HV0.2, approximately twice higher than that of the substrate. It's specific wear rate (3.974 mm3 N−1 m−1) was lower than that of the substrate (5.545 mm3 N−1 m−1). Compared with 904 L stainless steel, the corrosion current density of [Cr–Fe4Co4Ni4]Cr3-15vol%TiC composite coating reduced by nearly an order of magnitude, the impedance increased by 3.5 times.

Effects of agitator blade scaling on mixing in dissolving tanks

Hard calcium carbonate scale often forms on the agitators in smelt dissolving tanks. The effects of this scale on mixing are not well understood. While mixing in tanks has often been modeled in the literature, there have been no studies involving agitator scaling. To better understand the impact of agitator scaling on hydrodynamics and tank concentrations, a steady state, three-dimensional (3D) model has been developed for a smelt dissolving tank at a kraft pulp mill. In this work, four cases are compared: an agitator with no scaling, mild scaling, moderate scaling, and extreme scaling. The extreme scaling case is representative of scale buildup on a dissolving tank agitator that was significant enough that the agitator had to be stopped and cleaned. The reduction in the agitator fluid jet velocity is relatively small for the mild and moderate scaling cases, but it becomes more significant for the extreme scaling case, for which the results indicate that the mixing of the smelt with the weak wash is likely poor and that there would thus be a risk of smelt pooling.

Enhanced nitrogen removal from low COD/TIN mainstream wastewater in a continuous plug-flow reactor via partial nitrification, simultaneous anammox and endogenous denitrification (PN-SAED) process

A continuous plug-flow reactor with anaerobic/front-aerobic/anoxic/post-aerobic zones, where partial nitrification occurred in the front-aerobic zone, followed by simultaneous anammox and endogenous denitrification in the anoxic zone (PN-SAED), was built up to treat municipal wastewater. Alternating anoxic/aerobic conditions and longer anoxic duration facilitated stable partial nitrification. The nitrite accumulation ratio (NAR) was maintained at 97.4 ± 1.2%, with temperatures between 13.3℃ to 19.8℃. Candidatus Brocadia were naturally enriched in-situ from the anoxic zone with relative abundances of 31.93% and 6.67% on the agitator blade and carriers, respectively. High removal efficiencies of total inorganic nitrogen (TIN) (95.1 ± 1.9%) and effluent TIN (2.6 ± 1.1 mg N/L) were acquired from low COD/TIN (3.4 ± 0.4) municipal wastewater with anammox contribution of 13.5%±5.8% to TIN removal. The PN-SAED process is a promising mainstream nitrogen removal method.

Application of Theoretical and Experimental Findings for Optimization of Mixing Processes and Equipment

The homogenization of the agitated batch and ensuring the suspension of particles are the most frequently encountered requirements in terms of mixing applications. These operations are affected by the flow of the agitated batch. The geometrical parameters of the mixing system, especially the shape of the agitator blade, affect flow and circulation in the agitated batch. The present work provides a general description of the most common processes in the agitated batch (blending and particle suspension), hydrodynamic parameters (flow in agitated batches, pumping and circulation capacity of impellers) and the geometrical configurations of the mixing equipment (shape of vessel, baffle and impeller, and their mutual arrangement) that influence the process. The dimensionless process characteristics of the agitator were derived by theoretical analysis. These characteristics were applied to evaluate an extensive set of experimental data with various geometric configurations of the mixing equipment. This study shows how the flow in the agitated batch, caused by the pumping and circulating effects of the agitators, affects the parameters and energy efficiency of these processes, depending on the geometric configuration of the mixing equipment. Moreover, the benefits of the hydrofoil impellers used for these mixing processes are presented.

CFD Research on the Influence of 45° Disk Turbine Agitator Blade Diameter on the Solid–Liquid Mixing Characteristics of the Cone-Bottom Stirred Tank

A numerical simulation of a solid–liquid mixture concentration field in a cone-bottom stirred tank (diameter D = 150 mm) was conducted using computational fluid dynamics (CFD). The influence of the 45° disk turbine impeller diameter on the mixing time number of solid–liquid mixture, mixing energy per unit volume, concentration standard deviation, turbulence energy and turbulent dissipation rate as well as solid just-suspended impeller speed was analyzed. The Eulerian two-fluid model was employed along with the standard k–e turbulence model to simulate the turbulent solid–liquid flow in the cone-bottom stirred tank. A multiple reference frame approach was used to simulate the impeller rotation in a fully baffled reactor. The Fluent® 14.5 commercial CFD software was employed for the transient simulation. The radial and tangential velocities at the outer edge of the impeller along the blade width were compared with the experimental data of Wu and Patterson (Chem Eng Sci 44:2207–2221, 1989), Mahouast et al. (Entropy 133:7–17, 1987) and Kemoun et al. (IChemE Symp Ser 136:399–406, 1994). The further extended computational model could well predict the influence of impeller diameter on the solid–liquid mixing characteristics.

全自动调色机搅拌器叶片流场数值模拟研究

全自动调色机搅拌器叶片流场数值模拟研究

Micromixing efficiency in a multiphase reactor with a foam block stirrer

ABSTRACTA rotating foam reactor (RFR), which comprises a solid foam block stirrer as opposed to the agitator blade in stirred tanks, has recently received a significant amount of research interest due to its high mass transfer rates. For a deeper insight into the RFR the work herein investigated the micromixing efficiency of the RFR in terms of segregation index (Xs) using the iodide‐iodate reaction system. The effects of various operating parameters including injection time, rotational speed, acid concentration, volume of liquid, volumetric ratio, and gas flow rate on segregation index were systematically examined. Results showed that the segregation index remained constant when injection time exceeded 100 s. Moreover, the Xs increased with an increase in acid concentration but decreased with an increase in rotational speed, volume of liquid, volumetric ratio, and gas flow rate. Micromixing time was also calculated based on the incorporation model and was established to range from 1.1 × 10−3–4.5 × 10−2 s, which is much shorter than that of conventional reactors. The results herein demonstrate that an RFR exhibits excellent micromixing efficiency and has a significant potential for use in chemical industries.

New intelligent photometric titration system and its method for constructing chemical oxygen demand based on micro-flow injection

The characteristics of the signals during the process of chemical oxygen demand (COD) titration are analyzed in this paper. The signals are derived for normalized titration curves of reactions having the color mutation reaction. After analyzing the characteristics, the critical control points are observed. The switch, stop and end points are searched by the algorithm on a computer. Based on this three-point method, a new intelligent photometric titration system is constructed for COD, without using the calibration curves. Using this system, a new intelligent photometric titrator has been built for COD for automatic sampling and intelligent titrating. Under computer control, the process of titration is conducted intelligently and accurately; no manual operation or assistance is required. The titration chamber was homemade. The optimized conditions of the titration system are as follows: the titrant was consecutively micro-flow injected into the chamber with a velocity of 0.00576 mL·s−1; 100 points per second of the titrating process signal were collected; and the homemade agitator blade stirred at a speed of 420 rpm. The preferences tested by actual samples proved that this titrator meets the requirements of the standard method and is suitable for use in experiments. Overall, our approach facilitates adoption of an intelligent titrimetry system for the determination of photometric titration.

THE PERFORMANCE OF EXTRACTION EQUIPMENT MODIFICATION TOWARD SIZE <br> PARTICLE OF TUBER AND YIELD OF INULIN OF DAHLIA FLOWER TUBER

Isolation of inulin from starch generally is done by extraction method. The size of the material to be extracted will affect the extraction process performance. In laboratory scale, the size reduction was done with a knife and the separation of starch from tubers was done by juicer. Temperature fluctuations during the extraction process would affect the yield of inulin, hence juicers and waterbath were found ineffective for larger scale. This research was aimed to design an extractor equipped with agitator blades for size reduction and a temperature controller. Extractor performance was investigated by evaluating agitation time (60-150 minutes), distance between agitator blades on the shaft (5 and 7 cm), number of the agitators, (1, 2, and 3 blades) against the fineness of cut material, starch and inulin content. The results showed that the highest fineness of the samples was achieved at a distance of agitator blade of 7 cm, with 3 agitator blades and agitating time of 150 minutes. The highest yield of starch was 11.7% at size reduction time of 120 and 150 minutes using 3-blades agitator and the distance of 7 cm. The content of crude inulin obtained were by using the extractor was 2.206% and 2.213% by using the water bath. The difference of inulin content was 0.007% so it suggests that the extractor designed in this study can be used on inulin production in larger scale. The efficiency of the extractor was 85%.

Modeling of the process of oilseed meat cooking in a multi-vat cooker during processing of oil raw materials

A new method for determining design and technological parameters and the number of cooker vats for the moisture-thermal oilseed meat treatment has been proposed. The peculiarity of this technique is that the set values of the mean and mean-square oilseed meat moisture were taken as the criteria for the validity of the calculated data. A mathematical model of hydrodynamics of motion of the oilseed meat particles in the cooker vat was developed as a single process of motion of the oilseed meat fluxes along the horizontal concentric circles and along the vertical (meridian) ones traversing the vat axis. The basis of the model is the differential equation of particle motion along the blade rotating around the axis over the heated bottom of the cooker vat. The equation takes into account the design features of the stirrer, speed of blade rotation, length of the blades and physical characteristics of the oilseed meat expressed in terms of friction coefficients. Solution of the equation makes it possible to determine velocity of the particle in the direction of the blade and the circumferential velocity, the time of motion along the blade. This is the initial data for the axial movement of the oilseed meat. The time of passage of the oilseed meat along the agitator blade makes it possible to justify conditions of conductive heat exchange. The time of passage along the vat axis makes it possible to justify the conditions of convective heat exchange. A discrete model of the moving contact layer of the oilseed meat at the hot surface of the vat bottom was developed. Moisture content of the oilseed meat was described by a matrix in which the number of rows is equal to the number of elementary layers and the number of columns is equal to the number of elementary time intervals. The mass of the dry oilseed meat substance is determined by the row vector of the matter mass in the thick layer. Thermal balance of conductive and convective heat and mass transfer of the oilseed meat drying process has been compiled taking into account the heat spent for removal of the bound moisture from the solid phase which will ensure more accurate calculation of the technological conditions of cooking.

Design of Mechanical Agitation Biological Reactor Usedin Municipal Solidwaste Composting

In order to solve the problems of uneven mixing and aerating in municipal solid waste composting, we present a structural design of mechanical agitation biological reactor. The biological reactor system is composed of cylinder tank, agitator, motivation and drive device. The agitator shaft of reactor is hollow and has 24 holes under agitator blade. The article not only introduces the structural design and check of main body, and rack of reactor, but also the selection of type of arranger. The design of agitator gives consideration to both agitation and aeration, which makes air and materials mixed sufficiently during agitation and the fermentation is more fully.

Granulation of Core Particles Suitable for Film Coating by Agitation Fluidized Bed III. Effect of Scale, Agitator Rotational Speed and Blade Shape on Granule Properties and Development of a High Accuracy Scale-Up Theory

The preparation of core particles suitable for subsequent film coating was examined using different scales of agitation fluidized beds. Specifically, the effects of agitator rotational speed and agitator blade shape in different scales of granulators on granule properties such as mass median diameter, apparent density, friability and shape factor were studied. As the agitator rotational speed was increased or when the agitator blade height and angle were large, the mass median diameter and friability of the granules decreased, while the apparent density and shape factor increased, in a manner independent of the vessel size because the granules were subjected to greater compression, shearing and rolling effects. The same core particles could not be prepared using granulators with different vessel sizes by simply adopting a conventional scale-up theory(1,2)) based on kinetic energy similarity. Here, a novel scale-up theory that takes into account agitator blade shape factors is proposed.(3)) When the two scale-up theories were compared, our new theory was capable of predicting the granule properties more accurately than the conventional theory. By adopting this novel theory, the same core particles could be prepared under different operating conditions in any scale of granulator.

Numerical analysis of agitation torque and particle motion in a high shear mixer

Numerical simulation of particle motion in a high shear mixer was conducted using a three-dimensional discrete element method (DEM). Torque of an agitator blade, particle velocity profiles and forces acting on a particle were calculated under various agitator rotational speeds. The agitation torque showed a good correlation with the agitator rotational speed and reflected the particle motion in the mixer. The simulated results revealed that particles received greater forces near the bottom of the vessel, as compared to the upper or middle height in the mixer. The particle flow changed with the agitator rotational speed, as experimentally observed, and indicated different velocity profiles. Particle kinetic energy determined the agitation torque and the particle behavior, regardless of the complexity of the changes in the particle flow. A significance of monitoring of the agitation torque in the mixer is also discussed here from the perspective of the particle kinetic energy.

Scale-Up of High Shear Granulation Based on Agitation Power

Scale-up of wet granulation in a vertical high shear mixer was conducted. Pharmaceutical excipient mixtures composed of lactose, cornstarch and micro-crystalline cellulose, and hydroxypropylecellulose as a binder were mixed together and then granulated with purified water under various operating conditions and vessel scales. Torque of agitator shaft was continuously measured and then agitation power per unit vessel volume was calculated. The agitation power per unit vessel volume showed a good correlation with physical properties of obtained granules, such as mass median diameter, strength and compressibility. This implied that the scale-up characteristics could be well analyzed by means of the agitation power per unit vessel volume. In addition, the effects of agitator tip speed and Froude number on the agitation power per unit vessel volume were investigated. The results showed that the agitation power per unit vessel volume was well characterized by the tip speed rather than the Froude number. This meant that the granule growth mainly progressed by the shear stress from the agitator blade. Dynamic characteristics of high shear granulation were also discussed here.

Scale-Up of High Shear Granulation Based on the Internal Stress Measurement

Scale-up of wet granulation in a vertical high shear mixer was conducted. Pharmaceutical excipient powders composed of lactose, cornstarch and micro-crystallinecellulose, and hydroxypropylcellulose as a binder were mixed together and then granulated with purified water under various operating conditions and vessel scales. A novel internal stress measurement system was developed and stress of normal and tangential directions that granules received from the agitator blade during the granulation was continuously measured. The results indicated that granules received stress mainly from the tangential direction, which also showed the largest value near at the vessel wall. The effects of the agitator tip speed and the centrifugal acceleration on the measured stress was investigated. It was found that the tip speed of the agitator blade could be the main factor for the granule growth. The physical properties such as strength, size distribution and compressibility of granules prepared by changing the operating conditions and the vessel scales were evaluated and the scale-up characteristics of high shear granulation were investigated experimentally. The results showed that these physical properties had linear correlations with the tip speed. It was finally concluded that the scale-up of high shear granulation could be well conducted by means of the tip speed of the agitator blade.