Факультет технічних систем і енергоефективних технологій (ТеСЕТ)
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Item Design of a shelf pneumatic classifier for separating a polydisperse mixture of granulated superphosphate(РС ТЕСHNOLOGY СЕNTЕR, 2022) Юхименко, Микола Петрович; Yukhymenko, Mykola Petrovych; Острога, Руслан Олексійович; Ostroha, Ruslan Oleksiiovych; Bocko, J.The object of this study is a polydisperse mixture of granular superphosphate. It is emphasized that existing technologies of granulation and processing of granules lead to the formation of dusty fractions of small particles. The content of small fractions in the finished product should be minimal and, in connection with this problem, the task is to remove small particles from the mixture. The purpose of the current experimental study is to classify a polydisperse mixture of granular superphosphate in a pneumatic classifier. The device includes an inclined perforated shelf with an unloading space between its end and the wall of the apparatus. It has been experimentally revealed that the maximum efficiency of extraction into the entrainment of small particles is achieved with a width of the discharge space equal to 0.5 of the length of the cross-sectional side of the apparatus; the degree of perforation of the shelf is 5 %; the angle of inclination of the shelf is 25–30°; the speed of the gas flow in the free section of the apparatus is 3.7 m/s. It is shown that the degree of extraction into the entrainment of a small fraction less than 1 mm in size reaches 70–75 %, the content of the small fraction in the carry-over is 96–98 %, and the large fraction is less than 5 %. By processing experimental data, an empirical equation was built that makes it possible to determine the concentration of particles in the gas stream for individual fractions of the material. It is shown that due to the implementation of an active aerodynamic weighing mode, the shelf pneumatic classifier works at specific loads for air flow rate less than the typical designs of fluidized bed separators. It is noted that the effective operation of the shelf pneumatic classifier in the production of granular mineral fertilizers is ensured at a productivity of no more than 10–12 t/h. With greater productivity, there is a need to install several devices in the technological line.Item Experimental Studies and Condition Monitoring of Auxiliary Processes in the Production of Al2O3 by Sol–Gel Technology(MDPI, 2022) Склабінський, Всеволод Іванович; Склабинский, Всеволод Иванович; Sklabinskyi, Vsevolod Ivanovych; Ляпощенко, Олександр Олександрович; Ляпощенко, Александр Александрович; Liaposhchenko, Oleksandr Oleksandrovych; Piteľ, J.; Павленко, Іван Володимирович; Павленко, Иван Владимирович; Pavlenko, Ivan Volodymyrovych; Скиданенко, Максим Сергійович; Скиданенко, Максим Сергеевич; Skydanenko, Maksym Serhiiovych; Острога, Руслан Олексійович; Острога, Руслан Алексеевич; Ostroha, Ruslan Oleksiiovych; Юхименко, Микола Петрович; Юхименко, Николай Петрович; Yukhymenko, Mykola Petrovych; Simeiko, K.; Demianenko, M.; Volf, M.; Starynskyi, O.; Юрченко, Олександр Юрійович; Юрченко, Александр Юрьевич; Yurchenko, Oleksandr Yuriiovych; Мандрика, О.Powders and granules of heavy metal oxides produced through condition monitoring are in high demand as intermediate products for obtaining fine-grained ceramics for a wide range of applications, i.e., nuclear fuel and fuel elements for nuclear power plants. Sol–gel technology to produce nuclear fuel (UO2), as well as catalysts (ThO2) for organic synthesis in the form of granules from pressed microspheres, is a promising method to obtain powders and granules of heavy metal oxides (fine-graded ceramics). Al2O3 was selected as the model analog at the stages of obtaining a solution of heavy metal and sol, the formation and gelation of droplets, and the preparation of gel spheres and their further washing and drying, as well as recovery and firing of particles. In the study, the main parameters were substantiated, e.g., the diameter and angle of inclination of the axis for the holes in the perforated shell, the multiplicity of sol circulation before the holes, the coefficients of liquid (sol) flow rate, the oscillation frequency of the disperser, and the concentration of surfactant and acid in sol. All of these parameters affect the characteristics of the granules that are obtained by sol–gel technology. Moreover, recommendations to increase productivity and the energy efficiency of production were also given. In particular, it was found that oscillation frequency in a range of 70–80 Hz leads to a granulometric composition of the obtained granules of 2.0–2.2 mm. A hole of 0.85 mm and a frequency of 100 Hz slightly change this range to 1.2–2.0 mm, while maintaining monodispersity.Item Determining the main regularities in the process of mineral fertilizer granule encapsulation in the fluidized bed apparatus(PC Technology Center, 2021) Острога, Руслан Олексійович; Острога, Руслан Алексеевич; Ostroha, Ruslan Oleksiiovych; Юхименко, Микола Петрович; Юхименко, Николай Петрович; Yukhymenko, Mykola Petrovych; Bocko, J.; Артюхов, Артем Євгенович; Артюхов, Артем Евгеньевич; Artiukhov, Artem Yevhenovych; Krmela, J.This paper has substantiated the expediency and prospects of obtaining organomineral fertilizers by encapsulating mineral granules with an organic suspension in fluidized bed apparatuses. An overview of existing approaches to the mathematical description of the kinetics of granule growth in granulation processes in fluidized bed apparatuses is presented. A mathematical model of the kinetics of the formation of a hard shell around granules in a fluidized bed has been built. It shows that the kinetics depend on the size of the retour particles, the specific flow rate of the suspension, the density of the suspension and granules, and the time of the process. Equations have been derived for determining the thickness of the hard shell and the specific flow rate of the suspension for individual granulation stages in a multi-stage granulator of the fluidized layer. Analytically, graphical dependences were built, which showed an increase in the thickness of the hard shell due to an increase in the specific flow rate of the suspension, the diameter of the retour particles, and the time of the encapsulation process. The equations make it possible to determine the rational regime and technological parameters of the encapsulation process in order to obtain a coating of the predefined thickness at the surface of the granules. This ensures that a quality product is obtained, with a granulometric composition in a narrower range of particle size. To obtain granules of 2.5–4 mm in size, it is necessary to carry out the process in three- or four-stage granulators of the fluidized bed at specific suspension consumption of (10–20)∙10-4 kg/(kg∙s.). It is shown that with uniform growing of granules with a constant increase in the thickness of the shell in multistage granulators, the suspension consumption decreases by 2‒3 times from the first stage to the subsequent ones. This approach reduces the operating and energy costs of the process.Item Multistage Shelf Devices with Fluidized Bed for Heat-Mass Transfer Processes: Experimental Studies and Practical Implementation(MDPI, 2021) Юхименко, Микола Петрович; Юхименко, Николай Петрович; Yukhymenko, Mykola Petrovych; Артюхов, Артем Євгенович; Артюхов, Артем Евгеньевич; Artiukhov, Artem Yevhenovych; Острога, Руслан Олексійович; Острога, Руслан Алексеевич; Ostroha, Ruslan Oleksiiovych; Артюхова, Надія Олександрівна; Артюхова, Надежда Александровна; Artiukhova, Nadiia Oleksandrivna; Krmela, J.; Bocko, J.The article deals with the theoretical description and experimental study of the hydrodynamic and heat transfer properties regarding the operation of multistage gravitational devices of the fluidized bed with inclined perforated shelves. The peculiarities of the work and the implementation field of the multistage shelf units are described. A theoretical model to define the solubilizer’s velocity above the perforation holes, in the above-shelf space of the device and in the outloading gap, as well as the residence time of the dispersed phase at the stage (perforated shelf contact) of the device is presented. The results of experimental studies regarding the influence, made by the structural parameters of the perforated shelf contacts, on the distribution pattern of single-phase and gas-dispersed flows in the workspace of the device, on the intensity of interphase heat transfer are presented. The conditions to create active hydrodynamic operating modes of multistage gravitational shelf devices, which provide higher efficiency of heat-mass transfer processes, and with lower gas consumption and hydraulic resistance compared to typical fluidized bed devices, are proved. Peculiarities regarding the implementation of heat-mass transfer processes in multistage devices are described using heat treatment and drying processes as examples.