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176 AZERBAIJAN CHEMICAL JOURNAL № 1 2023 ISSN 2522-1841 (Online)
ISSN 0005-2531 (Print)
UDC 622.767.53.002.5
SEPARATION OF POLYDISPERSE SYSTEMS IN AN ENVIRONMENTALLY CLEAN
INSTALLATION
D.B.Shirinova, A.S.Bayramova
Azerbaijan State Oil and Industry University
Received 15.07.2022 Accepted 06.08.2022
The process was carried out on an environmentally clean separator device of a new type-a classifier. The technological parameters of the process, the geometric parameters of the installation are determined and the influence of changes in these parameters on the course of the technological process is studied. It is established that in a pneumatic classifier with a multistage, cylindrical separation section having steps of increased diameter and equipped with tips adjustable by an angle from 00 to 900 in the horizontal plane, it is possible to obtain fractions of the required quantity and size. By doubling the diameter of the next stage compared to the previous one, it was possible to create a pressure drop and separate the polydisperse material by changing the particle velocity. The ecological advantage of the processed technology is noted, since during the separation of dispersed particles, part of the dust contained in the powdery mixture leaving the unit with the flow of air (gas) is retained in a dry holder, and the rest is in water (absorber).
Keywords: dispersed systems, superphosphate, quartzite, crushed glass, steps, solid materials, dust, wet catcher.
doi.org/10.32737/0005-2531-2023-1-176-182 Introduction
The separation of finely dispersed material is one of the urgent problems of modern technology for classifying solid bulk materials used in various sectors of the national economy, such as powder metallurgy, chemical, petrochemical, and food industries [1-4].
The motion of particles of the dispersed phase is influenced by a large number of factors, of which it can be noted as: the weight of particles, dynamic pressure forces, collisions of particles with walls and with each other, electrostatic forces, particle rotations, etc. [5-7].
The role of the processes of separating granular materials is currently increasing due to the fact that, firstly, the requirements for the quality of raw materials and intermediate products are constantly increasing and, secondly, due to the growth in production volume for processing [7-8].
Fractionation of bulk materials is widely used as preparatory and finishing operations in the enrichment of minerals, processing of non-
metallic raw materials, in the production of metal powders, slag waste from metallurgical plants and thermal power plants, in the production of conditioned aggregates of concrete and crushed stone of various brands, in the production of almost all dry products of the chemical industry, including fertilizers, catalysts, etc.
It should be noted that despite the widespread use of classifiers used to separate bulk materials, there is currently no particular progress in their designs and intensifications [9-12].
The most common way to separate bulk materials into fractions is to sift them through a sieve. The sieve analysis gives satisfactory results only for fractions larger than 0.04 mm. For material fractions smaller than 0.04 mm, the grain composition is determined by sedimentation or centrifugation methods. These methods are based on different deposition rates of particles of different sizes [13-15].
Experimental part
The developed apparatus and technology for classifying bulk materials in the upstream gas
flow is designed for fractionation of material by size, shape and particle density, which can be used in oil refining, petrochemical, mining, metallurgical industry, construction and agriculture.
The developed pneumatic multistage classifier includes cylindrical separation sections, separation into stages with an increasing diameter (the diameter of each subsequent stage is equal to two diameters of the previous stage) and equipped with nozzles with tips with an adjustable angle from 0 to 900 to the horizontal plane, and the classifier housing is equipped with additional coils that removable coils with flange connections allow increasing the height of the housing, or to regulate the number of steps, this makes it possible to separate the bulk material into the required number of fractions; doubling the diameter of the subsequent stage compared to the previous one enables to create a pressure drop and separate the polydisperse material, change the speed of particles.
There are disadvantages in the separation of bulk products in production, as well as in the process of cleaning dust and gas mixtures released in this process.
The classifier used was mainly used for classifying dispersed particles and at the same time for air (gas) purification. The principle of operation of this device is as follows:
- direct flow of the transport agent (liquid or gas) and solid dispersed particles;
- vertically ascending heterogeneous system (solid and liquefying agent);
- reduction in the flow direction of a heterogeneous system;
- the ability to change the flow rate;
- the possibility of providing deagglomeration of fine dispersed particles in the structure to increase the efficiency of the separation device-classifier;
- the possibility of stabilizing the flow of a heterogeneous system;
- to reduce the vortex formation of the flow formed when the flow rate of the separated materials changes, in order to increase the separation capacity of the device;
- the possibility of forming a filtration zone in terms of particle settling;
- continuous discharge of the obtained fractions and inspection of the settling zone.
The advantages of the device are its operation in a wide range of temperatures and pressures, the possibility of using it as a chemical reactor, as well as the possibility of carrying out processes in a fluidized bed, simplicity of design, high efficiency, the ability to separate granules into fractions of any size, etc. The classifier we offer can also be used for stepwise filtering.
The advantages of the device are its operation in a wide range of temperatures and pressures, the possibility of using it as a chemical reactor, as well as the possibility of carrying out processes in fluidized beds, simple design, high efficiency, the ability to separate granules into fractions of any size, etc.
An additional tip and a wheel installed in the device allow you to adjust the efficiency and productivity of separation, and the wheel also allows you to change the height of the stage [16-18].
The gas-dust (solid) mixture enters the lower part of the classifier, where the conglomerate device is installed. Here, conglomerates (combining large particles with small ones) are destroyed due to the flow touching the inner and outer walls of the cylinders.
Reducing the flow rate creates good conditions for particle settling. Thus, particles with low flight speeds enter the settling chamber and from there continuously enter the receiver. Freed from particles of this size, the particles enter the second stages. Thus, at the stage (n+1) you can get (n) fractions.
The tightness of the system, the same diameter of the inlet and outlet pipes of the classifier do not allow interruption of the flow, which leads to a good aerodynamic mode in the classifier.
The two-phase flow passes through the stabilizing part of the classifier and enters the first stage, where the flow rate decreases. Dust particles, that cannot fly at such a speed, settle
in the annulus of the first stage and are separated in the form of the first fraction.
The flow leaving the first stage enters the second stage. Dust particles that cannot fly at such a speed settle in the annular space of the second stage, and the second fraction (dust) is separated from the outlet pipe of this stage. The two-phase current leaving the second stage enters the third stage, and at this stage the flow rate decreases, which allows the particles to settle. Particles that cannot fly at such a speed are ejected from the outlet pipe of the third stage into the receiver.
The experiments were carried out in identical classifier diameters (the diameter of each subsequent stage is equal to two diameters of the previous stage), at different values of the height of the steps, the consumption of solid material (crushed glass, quartzite and phosphorus fertilizers (superphosphate) and air. At the same time, the height of the step was changed, which affects the output of the finished product. Depending on the size, mass, shape, chemical properties of solid materials and the density of the solid phase, it was possible to control the technological parameters of the process in the device.
Experiments were conducted on the separation of granular substances (crushed glass, quartzite and granular superphosphate) by the size of granules and on the purification of air (gas) from these substances. The separation of these substances was carried out on a continuously operating, environmentally friendly, step-by-step installation. As can be seen, various materials were selected for mechanical, physical and chemical properties [19].
In industry, crushed glass is used to make contactors for household compressors. The best quality of the contactor is obtained when using crushed glass with a granulometric composition of less than 160 mkm.
It should be noted that the separation of solid materials with dimensions of 200 mkm in industrial conditions is carried out by the
screening method, which has a number of significant disadvantages. This process is also complicated by the fact that the crushed has poor flowability. The experiments were carried out on the developed installation, the conclusions are indicated in Table 1.
Quartzite is used for lining induction furnaces. By applying various fractions of quartzite, it is possible to increase the service life of induction furnaces. It is known that quartzite with particle sizes less than 630 mkm is used for high-quality lining of induction furnaces. The results of the studies carried out at the laboratory facility are shown in Table 2.
Granulated superphosphate is used as a phosphorus fertilizer for various crops. Separations of granulated superphosphate were carried out on a continuous-action unit. The results of studies on separation processes show that according to the developed method, it is possible to obtain granular superphosphate with various required particle sizes and further to solve the issue of fertilizer encapsulation. Obtaining narrow fractions allows us to qualitatively improve the development of encapsulation technology, which is currently a problem due to the polydispersity of the material Table 3.
In the process of classifying the dispersed particles mentioned above, the issue of capturing dust (gas) emitted as a result of the technological process into the atmosphere was simultaneously considered. For this, dry and wet catchers were used.
Water was taken as an absorbent to capture the emitted dust, and the air that was removed and analyzed after capture. From the results of the analysis, it became known that the concentration of dispersed particles in the composition of the air corresponds to the permissible concentration (Table 4).
Hence, we can conclude that, along with the classification of dispersed particles with a dust-gas mixture, it is possible to purify the gases (dust) emitted from the process [20-22].
Table 1. Classification of crushed glass
Quantity, g/h Content of classes, mkm,%
№ of expei iments Solid material (glass) Liquefied agent (air) Steps 315 200 160 100 63 50 Step height, mm Speed in steps, m/s
170 1020 Sour. 5.55 13.56 12.57 18.6 40.1 9.65 105 3.56
1 112 1020 I 4.46 13.8 12.5 18.75 42.4 8.03 85 0.1217
19 1020 II 5.26 14.2 10.5 25.25 31.58 13.15 45 0.025
40 1020 III 8.75 12.5 13.75 15.0 37.5 12.5 210 0.0104
220 956 Sour. 8.02 16.5 10.7 17.08 23.79 27 85 3.37
2 146 956 I 7.04 16.19 8.8 17.6 26.05 24.6 85 0.115
34.5 956 II 11.32 20.75 15.09 15.09 18.86 18.86 45 0.023
39.5 956 III 8.86 13.92 13.92 15.18 15.18 32.9 210 0.01
326 883 Sour. 1.229 8.735 8.798 19.86 19.14 42.226 75 3.12
3 180.3 883 I 1.2 10.4 8.6 20.5 29.2 30.1 65 1.106
85.3 883 II 0.34 5.66 6.8 17.5 18.4 50.3 45 0.0217
60.4 883 III 1.0 7.5 7.5 18.2 18.5 47.3 210 0.009
Table 2. Classification of quartzite
№ of experiments Quantity, g/h Steps Content of classes, mkm,% Step height, mm Speed in steps, m/s
Solid material (glass) Liquefied agent (air) 630 500 315 200 160 -100
1 275 883 Sour. 5.47 6.14 15.86 12.76 7.72 52.05 65 3.14
246 883 I 3.52 6.74 17.2 13.48 7.9 51.16 85 0.12
28.73 883 II - 0.54 2.9 5.46 5.1 86.0 45 0.216
0.27 883 III - - - 25.0 27.0 48.0 210 0.008
2 150 956 Sour. 8.02 16.5 10.7 17.08 22.7 24.0 85 3.37
143.5 956 I 7.04 16.19 8.72 17.6 26.05 24.4 85 0.115
5.7 956 II - - 19.3 20.04 27.8 32.86 45 0.023
0.8 956 III - - - - 46.18 53.82 210 0.01
3 260 1020 Sour. 10.81 8.68 14.7 12.95 24.56 28.3 85 3.67
248.8 1020 I 11.3 9.08 15.0 13.2 6.12 45.3 25 0.125
7.2 1020 II - - - - 22.0 78.0 45 0.025
4.0 1020 III - - - - - 100 210 0.0102
Table 3. Classification of superphosphate
№ of experiments Quantity, g/h Steps Content of classes, mkm,% Step height, mm Speed in steps, m/s
Solid material (superph osphate) Liquefied agent (air) 630 500 315 200 160 -100
1 120 883 Sour. 5.20 6.1 16.2 13.6 8.4 50.5 85 3.12
116.5 883 I 3.5 6.8 16.5 14.5 8.55 50.15 45 0.11
3.0 883 II - 0.48 3.62 5.75 5.15 85.0 45 0.023
0.5 883 III - - - 26.0 28.0 46.0 210 0.009
2 80 950 Sour. 8.02 16.5 10.7 17.08 23.7 24.0 85 3.36
74.1 950 I 7.04 16.19 8.72 17.6 26.05 24.4 65 0.115
5.2 950 II - - 19.3 20.04 27.8 32.86 45 0.023
0.7 950 III - - - - 46.18 53.82 210 0.01
3 110 1020 Sour. 10.8 8.65 14.8 12.95 24.5 28.3 85 3.56
96.5 1020 I 11.3 9.08 15.0 13.2 6.12 45.3 45 0.125
8.2 1020 II - - - - 22.0 78.0 45 0.025
5.3 1020 III - - - - - 100 210 0.011
Table 4. Separation of dispersed systems
№ Name of mixtures Number of dispersed particles, g
Sour. I Steps II Steps III Steps In the dry catcher In the wet the catcher
1 Quartzite-air 250 71.8 122.4 45.3 9.6 0.9
2 Crushed glass-air 200 87.2 103.3 8.7 0.6 0.2
3 Superphosphate-air 300 93.0 107.2 96.3 2.3 1.2
catcher catcher
The relationship between performance and product output: 1 - superphosfat-air; 2 - quartzite-air; 3 - crushed glass.
Results and discussion
The developed technology is environmentally friendly, since the outgoing air flow contains an insignificant amount of small particles that are captured by the absorber. Also, one of the main advantages is that two technological processes are carried out according to the same scheme - classification of dispersed particles and purification of separated dust (gas).
When classifying pulverized materials, part of the dust in the dust-gas mixture leaving the device by air (gas) flow is deposited in a dry catcher, and the rest is absorbed by water (absorbent). This prevents environmental pollution. Studies have shown that by changing the geometric and technological parameters of the device, granular particles can be divided into the required sizes. The most important thing is that in the presented device it is possible to classify bulk materials and simultaneously purify gases (by absorption or adsorption) with the release of any dust-gas mixture.
As already mentioned, the developed technology plays an important role in the classification of dispersed systems in the oil and gas, petrochemical, machine-building and other industries, in the sorting and classification of cereals in agriculture, as well as in environmental protection.
Conclusion
Various polydisperse particles (quartzite, crushed glass and granulated superphosphate) are divided into fractions in a pneumatic multistage cylindrical step classifier of a new type. The experiments were carried out with identical classifier diameters (the diameter of each next stage is twice the diameter of the previous stage), different values of the stage height, solid particles (crushed glass, quartzite and superphosphate) and air content. It turned out that changing the height of the steps affects the yield of the product (the proportion of the desired size). Depending on the size, density, shape and chemical properties of the solid phase, the technological parameters of the process in the apparatus can be adjusted. Thus, the influence of geometric parameters (the
height of the steps) and technological parameters (the air flow rate in the steps and the amount of compressed air) was studied devices for the process of separating each dispersed particle into fractions. It is determined that by adjusting the geometric and technological parameters of the device, it is possible to carry out the fractionation process of any size. During the experiments, it was found that when the particles are divided into fractions, there is no negative impact on the environment. Part of the smallest particles (dust) separated from the process is captured by a dry trap, and the rest is captured by a wet trap (absorber). In addition to the separation of bulk solids into fractions, catalytic processes, sorption and filtration processes can also be implemented in the device.
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EKOLOJi TOMÏZ QURGUDA POLÎDÎSPERS SÏSTEMLORIN AYRILMASI
D.B.Çirinova, A.S.Bayramova
Danavar hissaciklarin ayrilmasi prosesi içlanmiçdir. Proses yeni tipli ekoloji tamiz ayinci qurguda-klassifikatorda apanlmiçdir. Prosesin texnoloji parametrlari, qurgunun handasi parametrlari muayyanlaçdirilmiç va bu parametrlarin dayiçdirilmasinin prosesin gediçina tasiri ôyranilmiçdir. Muayyan olmuçdur ki, çoxkaskadli, silindrik ayirici seksiyali, artan diametrli pillalara malik va ufiqi mustaviya 00-dan 900 -a bucaqla tanzimlanan ucluqlarla tachiz edilmiç pnevmatik klassifikatorda talab olunan sayda va olçuda fraksiyalar almaq olar.Ovvalki pilla ila muqayisada novbati pillanin diametrini iki dafa artirmaqla, tazyiq duçgusu yaratmaga va polidispers materiali ayirmaga, hissaciklarin suratini dayiçdirmaya nail olunmuçdur. içlanmiç texnologiyanin ekoloji ustunluyu qeyd olunmuçdur, bela ki, Dispershissaciklarin aynlmasi zamani qurgunu hava (qaz) axini ila tark edan toz-qaz qançiginin tarkibindaki tozun bir hissasi quru tutucuda, qalan hissasi isa su (absorber) tarafindan tutulur.
Açar sozbr:dispers sistemlar, superfosfat, kvarsit, azilmiç §щз, pillalar, bark materiallar, toz, nam tutucu.
РАЗДЕЛЕНИЕ ПОЛИДИСПЕРСНЫХ СИСТЕМ В ЭКОЛОГИЧЕСКИ ЧИСТОЙ УСТАНОВКЕ
Д.Б.Ширинова, А.С.Байрамова
Процесс осуществлялся на экологически чистом сепараторном устройстве нового типа-классификаторе. Определены технологические параметры процесса, геометрические параметры установки и изучено влияние изменения этих параметров на ход технологического процесса. Установлено, что в пневматическом классификаторе с многокаскадной, цилиндрической разделительной секцией, имеющей ступени увеличенного диаметра и снабженной наконечниками, регулируемыми на угол от 00 до 900 в горизонтальной плоскости, можно получить фракции требуемого количества и размера. Удвоив диаметр следующей ступени по сравнению с предыдущей, удалось создать перепад давления и отделить полидисперсный материал, изменив скорость движения частиц. Отмечается экологическое преимущество обрабатываемой технологии, так как при разделении дисперсных частиц часть пыли, содержащейся в порошкообразной смеси, покидающей агрегат с потоком воздуха (газа), задерживается в сухом держателе, а остальная часть-в воде (абсорбере).
Ключевые слова: дисперсные системы, суперфосфат, кварцит, дробленое стекло, ступени, твердые материалы, пыль, мокрый уловитель.
