Pneumatic Separation Research Articles

An Evaluation of the Physical Characteristics of Seeds of Selected Lilac Species for Seed Sorting Purposes and Sustainable Forest Management

The aim of this study was to measure the physical attributes of seeds of selected lilac species and to describe the correlations between these properties and seed mass for seed processing and treatment. Basic physical parameters were measured in the seeds of five lilac species and the results were used to calculate aspect ratios describing seed shape and size. The average values of the measured properties ranged from 3.57 to 5.98 m s−1 for terminal velocity, from 6.20 to 9.61 mm for seed length, from 2.19 to 3.94 mm for seed width, from 0.85 to 1.21 mm for seed thickness, from 5.9 to 19.2 mg for seed mass, and from 32° to 44° for the angle of external friction. Seed mass was bound by the strongest correlations with terminal velocity (Amur lilac, Hungarian lilac, and Pekin lilac), thickness (broadleaf lilac), and width (Japanese tree lilac). Seed thickness followed by terminal velocity were the primary distinguishing features of lilac seeds. Therefore, lilac seeds should be sorted with the use of sieve separators with longitudinal openings or pneumatic separators. These devices effectively sort lilac seeds into fractions with uniform seed mass, which can facilitate the propagation of lilacs in nurseries and the production of high-quality seedlings, thus promoting the sustainable use of natural resources and production materials. In medium-sized and large seed fractions, the coefficient of variation of seed mass can be decreased by up to 50% relative to unsorted seeds.

Pneumatic separation and process simulation of waste printed circuit boards pyrolysis residue

In this study, the application of Z-shape pneumatic separator for separating metal and nonmetal particles in pyrolysis residue of waste printed circuit boards was investigated, and the flow field characteristics and particle motion behavior in the separator were revealed through flow field simulation. The pneumatic separation results indicated that pre-screening significantly enhanced the separation efficiency of metals and nonmetals in pyrolysis residue. The simulation results showed that the large gradient of airflow velocity distribution and the turbulent flow field within the Z-shape separation cavity are beneficial for dispersing particles and reducing the influence between particles of different properties, thus enhancing separation efficiency. Using Rocky DEM for modeling of different shapes and properties of particles, and then combined with ANSYS Fluent can better simulate the particle separation behavior in the pneumatic separator.

Collaborative sorting: integrating pneumatic separation and manipulator techniques for efficient coal gangue sorting

ABSTRACT Coal is one of the important sources to meet the global energy demand. The intelligent treatment of coal gangue is of great significance to environmental protection and resource recycling. In the treatment of gangue, the use of manipulator sorting alone faces the challenge of being difficult to adapt to the increasing sorting intensity and high cost of use. In this study, we propose a hybrid sorting system that combines pneumatic separation and manipulator sorting to address the limitations of pneumatic separation sorting and manipulator. We design a task assignment algorithm based on genetic algorithms to realize their collaborative work for optimal overall sorting efficiency in a sequence of gangue. Experimental results demonstrate that the collaborative sorting system, incorporating both manipulator and high-pressure pneumatic separation, outperforms the single pneumatic separation sorting system with an average increase in sorting efficiency of 20.66%. Furthermore, the collaborative system increased sorting efficiency by up to 76.09% compared to single manipulator sorting. These findings validate the effectiveness of our proposed approach in achieving efficient sorting of coal gangue.

Пневмоцентробежная классификация дисперсных частиц в процессе переработки зерна в муку

Russia enjoys a stable demand for flour products, including those obtained by the dry method of starch and gluten production. This study featured pneumocentrifugal parameters of fine particles in a spiral separator that classified milled grain into fractions, separated the solid phase from air, and identified the high-protein flour fraction in the flow. 
 Pneumatically classified flour was subjected to mathematical modeling and experimental research. The analysis of movement and deposition of particles in the working area covered particle mass, density, air-flow rate, and geometry, as well as their effect on the trajectory of particle movement and deposition. The experiment also involved the effect of air-flow rate and air-mix concentration on the classification efficiency.
 Particles from various grinding and break systems demonstrated classification modes that differed in soaring rate, size, and density. At an air-flow rate of 6–8 m/s, turn 1 of the spiral separator had the ratio of the internal coil radius to the inner pipe diameter as r1/dpipe = 7.9; it was r1/dpipe = 7 on turn 2 and fell down to r1/dpipe = 6.25 on turn 3; for all subsequent turns, the ratio was r1/dpipe < 5. Under these conditions, the fraction reached 160 µm and included small high-protein flour fractions with a particle size of 17–20 µm. The percentage of product accumulated on turns 1, 2, and 3 was 80, 12, and 8%, respectively. The maximal product separation efficiency of the third drain system was as high as 98% at an input rate of 6 m/s. The maximal separation efficiency for premium flour reached 99.2% at an input rate of 4.2 m/s.
 The separator proved efficient in classifying wheat grain flour into fractions as it was able to separate high-protein fraction and dispersed particles from the air flow. The separator could be used both as an independent device and as part of a complex technological scheme at the stage of pneumatic separators and unloaders.

Development of intelligent waste sorting system of low-value recyclable waste in Xiamen

The classification and recycling of waste are significant for environmental protection and resource conservation. In China, the fine sorting of low-value recyclable waste (LVRW) primarily uses manual sorting, which is inefficient and harmful to health. Automated sorting uses sensors to identify the type of waste on a conveyor belt, which is then automatically separated by a sorting organisation to improve the recycling process. A low-cost, high-performance sorting system was built in this paper. The system used a low-resolution industrial camera to capture colour images of waste and a pneumatic separator to sort the waste. The recognition accuracy of waste was improved by optimising the recognition model and using the copy–paste data augmentation method. Mark pneumatic valve control algorithm is proposed that achieves more than 99% waste recovery even under dense working conditions. The sorting system is suitable for sorting plants and has been applied to a case study of LVRW in Xiamen city. In the sorting experiments under complex working conditions, the purity and recycling rate of plastic and Tetra Pak wastes achieved over 95%. The experiment demonstrates the great potential of the system for waste recycling and will help solve the problem of municipal waste in developing countries.

Possibilities of using pneumatic separation in the scheme of preparation of samples containing individual inclusions

Possibilities of using pneumatic separation in the scheme of preparation of samples containing individual inclusions

КЛАССИФИКАЦИЯ СЫПУЧЕЙ СМЕСИ В ПНЕВМОСЕПАРАТОРЕ

The paper analyzes classification of crushed substances in high quality food production. The problem in the focus is the lack of analytical apparatus for calculating operating parameters of equipment for food processing. At the same time, the authors propose physical and mathematical model of maximum close to description of real mechanical process in quantitative analysis of crushed mixture classification. The article studies quantitative modeling of separation particle mixtures process in working volume of a pneumatic separator. The data obtained correspond to physical meaning of process under study and, accordingly, it established possibility of loose mixtures classifying based on pneumatic separator.

Аналіз одношарового руху зернового матеріалу у вертикальному пневмосепараційному каналі

The separation of grain and light impurities in a vertical pneumatic separation channel with an increase in its capacity occurs under rather difficult conditions, since the thickness of the grain flow increases, which leads to a redistribution of particles of grain material and reduces the probability of passing light impurities through the grain layers and their release into the sedimentation chamber. To increase the productivity of vertical pneumatic separation channels, it is necessary to create conditions for single-layer placement of grain material in the separation zone at a distance that excludes the interaction of other layers of grain input. This will allow the majority of grain particles to be in the same conditions and increase the percentage of probability of separation into the sedimentation chamber to the maximum value. Therefore, a theoretical flow analysis aimed at studying the interaction of grain mixture particles with the air flow, taking into account the single-layer arrangement of several grain layers and the contamination of the air flow with light impurities in the separation zone, is a rather important task. Theoretical dependences have been obtained that allow substantiating the main parameters of the pneumatic separation channel and determine the residence time of a grain particle in the separation zone, taking into account the clogging of the air flow. For a grain material of mass characterized by the values of the windage coefficient kз = 0.075...0.12 for full grain, kз = 0.11...0.14 for substandard grain, and kз = 0.125...0.55 for light impurities, it is possible to clearly separate the grain mixture into fractions by setting the appropriate parameters and operating modes of the pneumatic separation channel under the condition of a single-layer multilevel input. Due to the selection of rational parameters of the feeding devices for delivering the material into the separation zone and establishment of appropriate aerodynamic modes of air flow, it is possible to separate up to 96% of light impurities from the grain material, while ensuring minimal losses of full grain to waste.

Distribution of Heterogeneous, Highly Impure Soy Material in a Deep Air Channel

The paper highlights a lack of machines and equipment capable of cleaning highly impure soybean material efficiently and productively. Most of the existing grain cleaning machines are designed for the materials conforming to GOST 17109-88 that specifies weed and oilseed impurity contents of 2 and 6 percent, respectively. In reality, a typical soybean post-harvest waste often contains 20 to 60 percent of material unsuitable for extracting raw protein, that makes this type of material completely non–separable for this type of machine. (Research purpose) The research aims to determine the optimal efficiency of separating heterogeneous bulk mixtures in a vertically ascending air channel. (Materials and methods) To accomplish this, the authors employed a rotary batch classifier RBK 30 and a prototype sample of a precision air classifier PAC with column air flow accelerators. The paper defines impurity separation completeness and soybean waste separation efficiency in a novel pneumatic classifier, considering the accelerator thickness and the height above the processed material. (Results and discussion) The findings reveal that traditional pneumatic channels achieve no more than 20 percent of separation efficiency for highly impure soybean material, while the precision air classifier demonstrates approximately a 45 percent separation. (Conclusions) Typical air flow machines struggle with high impurity of material. The separation efficiency of highly impure material can be enhanced by equalizing the air flow velocity inside and above the layer of the separated material and installing a core air flow accelerator. The study indicates that the material being processed can be separated by air flow, provided a specialized pneumatic separation channel is used. Due to the ratio of the core accelerator height and the height above the material, the air flow velocity inside and above the separated layer is equalized.

Determination of the optimal modes of operation of the clover grater and scarifier KS-0.3 P during scarification

The article provides information about the features of the device, the quality of work of the prototype of a new 25...30 % more productive clover grater and scarifier KS-0.3 P in comparison with the analogue KS-0.2 P. KS-0.3P includes a drum-type wiping and scarifying device, a pneumatic separation device, a two-stage exhaust air purification system containing a cyclone and a fabric filter. The increase in the productivity of the new machine is achieved by increasing the diameter of the drum with a solid wiping surface to 0.45 m and the length of the oval deck with scarifying plates to 0.7 m. The solid grating surface of the drum is welded from steel rods of hexagonal profile No. 12 mounted on an edge. The deck covering the drum from below by 180° is made of round bars with a diameter of 10 mm and nine steel plates with a thickness of 2 mm and a width of 11 mm, evenly distributed along the length of the deck. When studying the technological process of clover grater and scarifier the method of mathematic planning of the experiment was used. The quality of scarification done was evaluated using the GOST 12038-84, GOST 12036-85 methodologies and additionally introduced indicator of variation of the number of germinated seeds. The material supply was regulated by the degree of opening of the flap in the loading hopper in the range from 0.2 to 0.4 t/h. The rotation frequency of the drum was changed by a frequency converter from 550 to 650 min-1. Eastern galega seeds met GOST 52325-2005 requirements. The experiments were carried out in three-fold repetition. As a result of an experimental study of the KS-0.3P cloverworm-scarifier during the scarification of the seeds of the Eastern galega, the ranges of the optimal drum rotation speed of 550... 650 min-1 and the material supply of 0.3... 0.4 t / h were determined, when the specified agrotechnical indicators were provided: the degree of scarification not less than 95.0 % and crushing not more than 1.5 %.

АНАЛИЗ КОНСТРУКЦИЙ ПНЕВМОСЕПАРИРУЮЩИХ СИСТЕМ

One of the main methods of separating a grain heap is pneumatic separation based on the difference in the aerodynamic resistance of the components of the grain mixture to the air flow. A classification of pneumatic separating devices is given according to the following parameters: method of air flow circulation, number of separating channels, method of using systems, direction of air flow in separating channels and chambers, method of supplying air to the pneumatic separation zone, frequency of processing, shape of pneumatic separating channels, method of feeding grain mixture into the channel , type of devices for separating light impurities, method of regulating air flow in the channel. The formulas developed by different authors for the coefficient of particle resistance to air flow are generalized. The optimal dimensions of the pneumatic channel have been established: the depth of the channel should not exceed 200 mm, and the width should not exceed 1500 mm. It has been established that the most commonly used shape of the pneumatic channel is rectangular. It is shown that various devices are used to introduce grain material into the pneumatic channel: pitched boards, support nets, corrugated rollers, spreading discs, vibration, belt, pneumatic, and combined devices. According to the direction of the air flow, separators are distinguished: vertical, inclined, horizontal. It has been established that louvered inertial dust collectors are usually used to clean the air from dust. The most modern designs of cross-flow fans are considered. Based on the analysis performed, recommendations were given to developers of aspiration systems: to ensure a margin of pneumatic channel width so that with an increase in the supply of grain material, the efficiency of air cleaning does not decrease, but at the same time the uniformity of the air flow in the pneumatic channel does not decrease.

Quantifying narrowing partition thickness in a vertical pneumatic separation channel for soybean seed cleaning

The paper highlights that the study of the soybean seed separation processes in a vertical deep aspirating channel contributes to the improvement of technical and economic indicators in grain cleaning equipment. (Research purpose) The research aims to substantiate the thickness of narrowing partitions in the vertical deep aspirating channel. (Materials and methods) A prototype of a vertical deep aspirating channel with three sections of varying height, was used for cleaning soybean seeds. The optimal thickness of the narrowing partitions in the channel has been justified. Impurity extraction completeness and seed separation efficiency within a vertical aspirating channel were assessed for soybean seed cleaning under maximum specific grain load conditions. (Results and discussion) The following parameters have been determined: the optimal thickness for the narrowing partitions is 70 millimeters under a maximum specific grain load of 5 kilograms per square centimeter per hour. Seed losses do not exceed 3 percent in the aspirating channel with narrowing partitions, with impurity extraction completeness of 74 percent for the «Waste» fraction. The efficiency of the separation process stands at 71 percent, and the purity level of the «Seeds» fraction reaches 81 percent in a single pass during the preliminary cleaning stage. (Conclusions) It has been established that the use of narrowing partitions in a vertical aspirating channel during soybean seed cleaning leads to an increase in the specific grain load up to 5 kilograms per square centimeter per hour, compared to 2 kilograms per square centimeter per hour achieved by traditional pneumatic separation channels. The proposed technical solution reduces soybean seed losses to 3 percent (compared to the initial requirements of no more than 10 percent) in a single pass and reduces machine power consumption from 4.5 to 2.25 kilowatt-hours.

Study of a pneumatic separator for grain cleaning

This article deals with experimental studies of a pneumatic separator with a passive deck. Post-harvest handling of grain is one of the important operations in grain production. Quality cleaning and drying contribute to grain storage without significant losses. The grain litter after the harvest of the combine harvester, which takes place in the shortest possible time, is the most clogged. This causes a problem in terms of cleaning. An important problem is also the physical and obsolescence of the cleaning machines, even though the annual workload is relatively small. This has a significant impact on productivity. Of all those in the agricultural industry, the most commonly used separation of grain from impurities is by aerodynamic properties and separation by size on the sieve. The design of an experimental pneumatic separator with a passive deck was developed. Experimental studies of the pneumatic separator with a passive deck were carried out, based on which plots of the dependences of the completeness of the separation were plotted on the angle of inclination of the flap and the feed of the grain material. The optimal parameters and modes of the grain cleaning machine were determined: the lowest losses of the main crop and the cleaning efficiency are achieved at the flap inclination angle α=0˚.

Research of the process of air separation of grain material in a vertical zigzag channel

The aim of the research is to determine ways to improve the efficiency of grain materials pneumatic separation based on the study of the interaction mechanism of grains with the air flow in the channel elements, which are inclined sections of the air duct. The paper considers a modified separation method that separates the grain material according to the aerodynamic properties of the components in a vertical zigzag air channel in an aerodynamic and gravitational field. The studies were carried out by means of mathematical modeling followed by experimental confirmation of the modeling results. A computer mathematical model was created in the MathCad 13 application package to determine the parameters of the zigzag aspiration channel. This model describes the influx of parameters in the channel (width, height, cut of the zigzag ledge to the horizon, edge of the zigzag ledge) on the nature of the grain trajectory. As a result of the numerical simulation process using the mathematical package Mathematica, dependence was obtained to determine the trajectory of motion depending on the angular velocity. An increase in the pneumatic separation effect during the grain mixtures division due to the influence of the Magnus effect was established as a result of experimental studies. The design of a zigzag separator with an annular channel section has been improved based of the research carried out.

Areas of Improvement of Feeding Devices for Pneumatic Separation Channels

Despite a significant degree of improvement of modern pneumatic separators, the method of feeding grain material into the channel remains an important issue today. The article provides an overview of feeding devices, their classification, and the design which is aimed at improving the interaction of the grain mixture with the air flow in the working area of separation. Promising directions for improving feeding devices of vertical pneumatic separating channels are outlined. On the basis of the review, the importance of practical application of additional technical means that contribute to the layering of the grain mixture both before entering and in the working area of the pneumatic separation channel is determined.

Analysis of constructions of technical means for separating seeds by density

Purpose. To intensify the seed separation process based on density through the justification of a new separator design. Methods. Conducting a literature and patent search to analyze the designs of grain-cleaning machines with combined action on grain using disruptive forces. Results. The choice of fractionation characteristics, the sequence of placement, and the composition of working elements in technological lines should be given great importance during fractionation. The universality of the use of combined grain cleaning machines reduces their nomenclature and limits the possibilities of using individual working elements. The use of various physico-mechanical indicators in the division of grain material leads to obtaining fractions with different properties and possibilities for further use. In particular, the density of individual seeds (saturation, density) is an important characteristic by which the material is divided during seed preparation for sowing, since this characteristic has a direct impact on the energy of germination and the similarity of the plant. Division of grain material by seed density can only be carried out if the seeds are pre-calibrated. Currently, pneumatic tables, pneumatic vibrating tables, pneumatic separators and other machines with combined action on the seed are used for seed fractionation by density Since it is not always possible to separate the raw material into fractions by individual impurity types or to isolate individual fractions in a pure form due to its multicomponent nature, imperfect working elements, and constantly changing composition of the raw material, in most cases, fractions containing the same components as the original grain material, but in different proportions, are obtained in production. In this regard, combined technical means should be used for fractionation processes, which will combine working elements (air channel, sieve, trier, etc.), but for optimal loading of each of them simultaneously with fractionation, flexible adjustment of the volume and quality of the obtained fractions depending on the condition of the original grain material is necessary. The need for such adjustment arises due to the continuously changing composition of the raw grain material. Conclusions 1. Analysis of the designs of technical means for separating seeds by density shows that known machines have the same specific indicators and do not differ significantly in the principle of action on the material. 2. The necessity of determining the feasibility of grain material separation taking into account its physical and mechanical properties has been established. 3. To reduce the energy consumption of cleaning and separating grain material for the purpose of obtaining high-quality seeds, it is necessary to justify complex technological schemes considering the nature of the processed material. 4. Criteria for flexible control of quantity, volume of obtained fractions, their quality, and parameters for the real-time assessment of the technological process using automated systems have been determined. 5. New combined working tools for separation processes have been substantiated depending on the stage of grain material processing and its qualitative composition, leading to the development of new technical means based on division characteristics and multiple criteria. 6. It has been established that the development of flexible fractional cleaning and seed separation schemes based on density, as well as the assessment of the economic efficiency of applied technological and technical solutions, enable seed producers to reduce production costs and increase the profitability of the enterprise. Keywords: separator, grain fractionation, sorting, pneumatic conveying, intensification of the partition process.

New technologies for diamond ores beneficiation

The main objective of the work is the development and implementation of technology and apparatuses for dry beneficiation of diamond-bearing ores and the creation of a fundamentally new class of modular mobile ore dressing units (MMODU). The article deals with the current state of crushing plants and pneumatic apparatuses. The results of the research of disintegration of lump ore in the DKD-300 crusher and comparison with foreign-made centrifugal impact crushers NP 1007 of the firm "Metso Minerals" by crushing degree are given. The comparative results of the extraction of minerals of different density are given in two types of pneumatic separator with straight and screw-shaped working chambers. The article considers the prospects of introducing dry technologies of mineral processing and beneficiation, which will significantly reduce the cost of diamond production.

Design and Optimization of Pneumatic Separation Device for Plastic Evidence in Fire and Explosion Scene

To improve the efficiency of fire investigation, a horizontal pneumatic separator for separating plastic evidence from fire and explosion scenes is designed in this paper. Taking three kinds of material with different densities as separation objects, MATLAB was used to calculate the horizontal displacement of materials under different separation parameters based on the motion equation. A deviation coefficient was put forward to measure the separation effect. The effects of air inlet velocity and air inlet angle on the deviation coefficient of materials with different particle sizes were studied, and the optimal deviation coefficient was determined according to Taguchi methods.

Scientific experimental bases for dry beneficiation of mineral ores

The article presents the results of research on the development of processes and equipment for ore preparation and pneumatic dry beneficiation of mineral ores. The methods of crushing and grinding before enrichment of minerals have been considered, dry enrichment of geomaterials is investigated. Highly efficient prototypes of beneficiation equipment are developed and tested: crushers of multiple dynamic impact RD-MDV-900, DKD-300, centrifugal grinders CMVU-800 and VCI-12, pneumatic separator POS-2000. Fundamental designs are created, and a number of new ore preparation and pneumatic beneficiation instruments are being designed. The efficiency of approbation of an autonomous dry beneficiation complex with new safe environmental standards for the processing of gold-bearing ores, which makes it possible to fully release and extract free gold with a particle size from 10,000 to 100 µm, is shown. The introduction of the dry beneficiation method is very promising for the mining industry. It will allow to reduce capital costs for the construction of stationary beneficiation plants, completely or partially withdraw from the use of process water, the construction of a water supply system, a traditional tailing dam, etc.

ОСНОВНЫЕ ТЕНДЕНЦИИ РАЗВИТИЯ ЗЕРНООЧИСТИТЕЛЬНОЙ ТЕХНИКИ

The main directions of research concerning post-harvest grain processing have been established: the first category includes cleaning methods, the second separator design, and the third grain cleaning technology. The most frequently used cleaning methods are highlighted. It is established that modern machines for primary grain processing use two-channel aspiration systems and three sieves in one tier of the sieve mill. The differences and advantages of air-sieve machines are shown. The low efficiency of pneumatic separators as independent devices for grain cleaning is shown: when feeding grain material of 7.9 t/h, the purity of the material when using the PS-15 separator increased from 98.16% to 98.70%; when feeding 9.6 t/h from 98.02% to 99.03%; when feeding 13.4 t/h from 97.73% to 98.04%; when feeding 14.9 t/h from 98.12% to 98.77%; when feeding 16.0 t/h from 97.55% to 98.29%. The efficiency of energy-saving gravity separators ZG-5 is shown: the content of the weed impurity when using it decreased to 0.67...0.98%, grain impurity up to 0.87...1.25%. The main objectives of various grain cleaning equipment are outlined: basic cleaning, isolation of difficult-to-separate impurities, obtaining high-quality seeds, energy saving. Two main new technologies of grain purification are given: fractionation and differentiation of grain heaps. Recommendations for developers of grain cleaning equipment are given.