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Item Analysis of Changes in Global Warming Potential during Enrichment and Production of Battery-Grade Graphite Using Electrothermal Fluidized Bed Technology(IOP Publishing Ltd, 2024) Hubynskyi, Semen M.; Sybir, Artem; Fedorov, Serhii; Usenko, Andrii Yu.; Hubynskyi, Mykhailo V.; Vvedenska, TetyanaENG: The greenhouse gas emissions during the production of anode class graphite for the conditions of Ukraine have been calculated. Conventional technologies and technologies using electrothermal fluidized bed (EFB) for natural and synthetic graphite have been studied. Calculations are carried out with respect to the whole technological chain, starting from extraction and processing of raw materials and ending with finishing processing (coating). As a result, it is shown that the technology of using EFB for purification of natural graphite and graphitization of synthetic graphite is competitive in terms of global warming potential (GWP). In the production of natural graphite using thermal purification with EFB instead of chemical purification, emissions of greenhouse gases practically remain at the same level. At the same time, the use of acids is eliminated, and the environmental impact associated with them is reduced. Production of synthetic graphite of anodic quality in EFB furnaces allows to reduce greenhouse gases (GHG) emissions by 40-50% in comparison with traditional graphitization technologies in Acheson and Kastner furnaces. The effect is achieved by reducing energy and raw material consumption.Item Development of a New Ergonomic Risks Management Algorithm on the Example of Drivers(РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, 2024) Tsopa, Vitaliy; Cheberiachko, Serhii; Cheberiachko, Yurii; Deryugin, Oleg; Chencheva, Olga; Rieznik, Dmytro; Klimov, Eduard; Lashko, Yevhenii; Pashko, Dmytro; Biliaieva, Viktoriia V.ENG: The object of the study: the process of determining and managing ergonomic risks at workplaces when performing professional activities on the example of truck drivers. The problem lies in uncertainty when making decisions in occupational safety and health management systems. The hypothesis of the study was the possibility of assessing ergonomic risks in the occupational safety management systems of organizations based on the identification of regularities between the load index, typical working postures when performing operations and the intensity of joint movements. An ergonomic risk assessment algorithm was developed, taking into account the load index, which includes a sequence of eleven steps, which can be conditionally divided into three groups. The first is determination of the intensity of joint movement. The second is the determination of the impact of activity and the duration of the production task. The third is determining the impact of environmental factors. An assessment of the ergonomic risk of drivers was carried out for three types of production work: driving a vehicle, replacing a damaged wheel, and repairing a car. At the same time, the ergonomic risk assessment algorithm takes into account the worker’s individual state of health and environmental factors, as well as experience and work experience. It has been established that there is a high level of ergonomic risk during car maintenance due to the highest total load index, which is 30 % higher compared to other types of work of vehicle drivers. The practical application consists in the development of a universal check list of drivers based on an algorithm to determine the ergonomic risk of workers at workplaces, which consists of 11 steps.Item Effect of Parameters of the Anthracite Heat Treatment on the Properties of Carbon Materials during Shock Heating(Ukrainian State University of Chemical Technology, Dnipro, Ukraine, 2022) Sybir, A. V.; Hubynskyi, M. V.; Balalaiev, K. B.; Burchak, O. V.; Sukhyy, K. M.; Fedorov, S. S.; Pinchuk, Valeriia O.; Hubynskyi, Semen M.; Vvedenska, T. Y.ENG: The aim of the study was to experimentally determine the effect of the heat treatment parameters of anthracites from Donetsk basin on the properties of carbon materials when using shock heating, typical of furnaces with a fluidized electrothermal bed. Anthracite was treated in an electric thermal furnace at the heating rate of 1000 K/min and the holding time of 10–20 min. The processing temperature range was 1500–30000Ñ. For processing, we used initial anthracites and anthracites after calcination at 1100–12000Ñ. The properties of the carbon material were investigated by X-ray radiographic analysis, XRF analysis and diffuse reflectance infrared Fourier transform. It was found that precalcination did not produce any effect on the properties of anthracite carbon materials during shock heating and holding time less than 1 hour. Based on the results of studies of anthracite heat treatment while changing the holding time, the following kinetic characteristics of transformations during shock heating were determined: the pre-exponential coefficient of 1.79 and the apparent activation energy of 103.85 kJ/mol. Thermal processing of anthracite from Donetsk coal basin in electric furnaces with the fluidized bed at the temperature 30000Ñ for 55–60 min allows obtaining the crystalline structure characteristic of artificial graphite with necessary electroconductivity and element composition.Item Efficiency of Low-Calorific Fuel Use in Counterflow Lime Kilns(D.A. Tsenov Academy of Economics, Svishtov, Bulgaria, 2023) Foris, Svitlana M.; Pererva, Valeriia Ya.; Usenko, Andrii Yu.; Foris, Oleksiy M.ENG: Highly expensive energy carriers require revision of the existing engineering approaches in heating of industrial furnaces. The paper presents the results of research into the performance of a shaft kiln for lime-stone burning, which was fired with mixtures of natural gas and a fuel gas of a low calorific value. On the basis of studying various schemes of fuel distribution between the burners, the optimal operation mode of the kiln with reduced consumption of natural gas by 30% was identified. The lime quality indicators increase when the blast furnace gas is supplied to the central burner and improve when supplied to the peripheral burners. The joint supply of blast furnace gas in the calorific value section of the natural blast furnace mixture 9.4 ÷ 35 MJ/m3 allows keeping the performance of the furnace unchanged. At the same time, the coefficient of replacing natural gas with blast furnace gas is close to unity The proposed mode of heating the furnace with a capacity of 200 t/day with a natural blast furnace mixture provides 30% natural gas savings.Item Energy Efficient Water-Cooled Elements for Foundry Class Electric Arc Steelmaking Furnaces(НМетАУ, Дніпро, 2021) Timoshenko, Sergii; Nemtsev, Eduard; Gubinskij, MikhailENG: Analysis of recent research and publications. Low energy efficiency of foundry class electric arc steelmaking furnaces (EAF) mainly is caused by heat loss in massive refractory lining during forced downtime. A low-power transformer doesn’t allow, in the conditions of classical technology, practice of traditional water-cooled elements in order to replace partially the lining, what determines increased refractory consumption. Known mathematical models of heat and mass transfer in the EAF working space don’t pay sufficient attention to the features of thermal state and energy loss in water-cooled elements in relation to foundry class furnaces. Purpose. Work aims to improve energy efficiency and refractory savings in foundry class EAF due to water-cooled elements design improvement. Method. Work is based on numerical modeling of heat exchange by radiation in the working space of the EAF and thermal state of water-cooled elements with spatial structure. Research findings. On the base of radiation heat exchange study, a multiple regression equation for power of heat loss with cooling water was obtained, taking into account capacity of the furnace, steelmaking bath shape factor (diameter to depth ratio), duration of technological period of the heat and averaging coefficient of heat flux through working surface of water-cooled element. For traditional one-row, two- and elaborated three-row panels averaging coefficient is 0.82, 0.67 and 0.61, respectively. Practical significance. Three-row water-cooled wall panels with a spatial structure are elaborated, which provide a decrease in heat loss with cooling water by 14 %, in comparison with two-row ones and by 40% in comparison with traditional one-row panels with dense structure. Estimates of optimal relative cooled surface for 3-12-ton EAF working space, providing refractory savings up to 25-30% due to three-row water-cooled panels installation, are substantiated.Item Environmental Engineering, Innovations, and Management. Editorial Review(Begell House Inc., USA, 2023) Kuzmin, Andrey; Pinchuk, Valeriya A.ENG: In recent years, special attention has been paid to environmental safety in various fields of application. Among all human activities, applications related to energy are always in high demand. At the same time, many of them affect climate change and can lead to biodiversity degradation and other environmental problems. The International Journal of Energy for a Clean Environment is a periodical that publishes high-quality research on the intersection of energy and the environment. The current issue of the journal presents the results obtained by researchers from different countries and different fields of research, devoted to some points in the field of energy and environmental management.Item Identifying Regularities in the Propagation of Air Ions in Rooms with Artificial Air Ionization(PC TECHNOLOGY CENTER, 2023) Levchenko, Larysa; Burdeina, Nataliia; Glyva, Valentyn; Kasatkina, Natalia; Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Tykhenko, Oksana; Petrunok, Tetiana; Biruk, Yana; Bogatov, OlegENG: The object of the study is the dynamics of air ion spread in rooms from the source of artificial air ionization under different starting conditions. There is currently the problem of distribution of air ions in the room with regulatory concentrations in all critical zones. An effective method of ensuring proper air ion concentrations is to model their propagation from ionization sources. Existing approaches to calculating the dynamics of air ions of both polarities have been improved in this study. Unlike known solutions, the impact on their concentration of electrostatic field and the interaction of air ions with suspended particles was taken into account. A model of air ion propagation in rooms with artificial air ionization and the principles of its numerical modeling was built. The use of Laplace Equation in the aerodynamic model instead of the Navier-Stokes equation for the potential of the flow rate has made it possible to design an "Ion 3D" tool, which reduces the time of implementation of one scenario from several hours to 7 seconds. Modeling of the propagation of air ions of both polarities in the room under different initial conditions was carried out. Two-dimensional and three-dimensional models with their visualization was implemented. The peculiarity of the resulting models is that they make it possible to determine the concentrations of air ions in any section of the room by three coordinates. Given this, the rapid selection of the variants of the source data makes it possible to achieve the normative values of concentrations of air ions in the area of breathing – exceeding 500 cm-3 of each polarity. Simulation makes it possible to design a room in which, under the condition of artificial ionization of air, the concentrations of air ions close to the optimal values of 3000–5000 cm-3 are provided.Item Major Lessons Learnt from an Online Teaching of Automation and Control Courses during the Pandemic and the Way ahead: A Critical Interpretative Synthesis(Public Organization "Ukrainian Assembly of Doctors of Sciences in Public Administration", Kyiv, Ukraine, 2023) Таrasevich, Iryna G.; Tarasevich, Alena V.; Foris, Svitlana M.; Kuzmenko, Mykhailo Y.ENG: Covid-19 brought in adapted frameworks, concepts, and tools into the design and delivery of automation courses at technical universities. Although university digitalization has been around for a while, it has been used primarily for the administrative purpose rather than for teaching and learning. A natural, powerful stimulator, the pandemic pushed the universities to explore new avenues in further digitalization of education. The goal of this critical interpretive synthesis is to make a summary of the major lessons learnt from the online teaching of automation courses during the pandemic and their further implementation. It is also aimed at exploring major tensions and barriers that users (teaching faculty, students, and administrative personnel) have been grappling with. The tensions and barriers are presented in this paper from three distinct perspectives – from the perspectives of students, teaching faculty, and university administrators. Whether students thrive or survive, the faculty rethink and upskill their teaching, and the institution is capable of meeting multiple, often competing needs and shifting priorities of the market – warrants further research on the topic. An important question to be addressed in future inquiries is whether the stakeholders that are engaged in the process of developing, teaching, and taking an automation course, are able to reconceptualize their roles and continue to grow professionally.Item Methodology for Modeling the Spread of Radioactive Substances in Case of an Emergency Release at a Nuclear Power Plant(National Technical University «Kharkiv Polytechnic Institute», Kharkiv, 2023) Levchenko, Larysa; Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Ausheva, Nataliia; Tykhenko, OksanaENG: The methodology for modeling the propagation of accidental releases of radionuclides from a power unit of a nuclear power plant has been developed. The calculation method takes into account the most critical factors propagation cloud - wind direction and speed, the intensity of the release radionuclides change: semi-continuous release, long-term release, instantaneous release. Diffuse processes and the presence of interference in the form of buildings were also taken into account. To solve the modeling equation of the aerodynamic model, the velocity potential equation is solved. The use of this equation instead of the traditional Novier-Stokes equation makes it possible to rationalize the calculation process in terms of the speed obtaining simulated data. To build a numerical model, a rectangular difference grid is used. The velocity potential and the quantities values of volumetric activity are determined at the centers of difference cells. The value of the airflow velocity vector component is determined on the sides of the difference cells. A finite-difference splitting scheme is used for numerical integration of the equation convective-diffusion transfer radionuclides. A computer code was developed on the basis of the constructed numerical model, the programming language Fortran was used. The approach used makes it possible to reduce the time for obtaining one scenario of an accident development. The cloud propagation dynamics determining is carried out almost in real time. This allows you to quickly respond to changing situations and make adequate decisions.Item Modeling the Distribution of Emergency Release Products at a Nuclear Power Plant Unit(Національний технічний університет "Харківський політехнічний інститут", 2024) Biliaieva, Viktoriia V.; Levchenko, Larysa; Myshchenko, Iryna; Tykhenko, Oksana; Kozachyna, Vitalii A.ENG: Despite the fact that much attention is paid to the safe operation of nuclear power plants, there is a possibility of an accident with the release of radionuclides. This is especially true in Ukraine, where there is a threat of the damage to nuclear reactors as a result of military operations. It is impossible to research the distribution of products emergency releases radioactive substances in laboratory conditions. Therefore, the only tool for the development predicting of an accident is the modeling the spread of a radionuclides cloud. The purpose of the research is a modeling the distribution of emergency release products in a nuclear power plant unit, suitable for the operative assessment of a development an accident. Results of the research: The mathematical model of the distribution emission products of a nuclear power plant has been developed, which takes into account the value of the initial activity of emission products, the rate of the settling radioactive particles, the wind speed components, the intensity changes radionuclide emission over time. The technique for solving the boundary value problem of modeling in conditions of a complex shape of the computational domain, taking into account the presence of obstacles to the spread of emission products has been developed. The use of the velocity potential equation in evolutionary form allows us to speed up the calculation process. The chosen splitting scheme of an alternating-triangular method allows to find the speed potential according to the explicit form at each splitting step. This allowed software implementation of the CFD model. The visualized models of the emission cloud distribution allow to determine the radiation situation in any place of the emission product distribution zone. The developed model makes it possible to quickly predict the development of an accident in space and time, which makes it possible to take measures to protect people from exposure in the shortest possible time. Conclusions: The obtained emission cloud propagation models and their visualization make it possible to determine the state of environmental pollution under various initial conditions during the development of the accident.Item Numerical Modeling of the Wind Regime on the Beaches of the Wash of the Artificial Storage Facilities for Mineral Processing Waste(IOP Publishing, 2024) Lapshyn, Yevhen; Biliaiev, Mykola M. ; Biliaieva, Viktoriia V. ; Halchenko, Zariana; Medianyk, Volodymyr; Buketov, ValentynENG: A 2D numerical model has been developed to estimate the airflow velocity field when flowing around the dam of an artificial storage facility for mineral processing waste. To solve the aerodynamic problem of determining the air flow velocity field when flowing around such hydraulic structures with a complex geometric shape, a potential motion model was applied. The numerical integration of the equation for the velocity potential is carried out using the Liebman method. The geometric shape of the tailings storage facility is formed in a discrete model using the marking method. A computer program was created to implement the developed numerical aerodynamics model. Based on the processing of the results of computational experiments, coefficients were obtained that allow us to quickly determine the value of the air flow velocity at the beginning and end of the tailing pond beach, i.e. in the area of the most intense dust emission. This allows for a quick prediction of the risk of dust air pollution at different tailing pile heights.Item Peculiarities of High-Temperature Refining of Carbon Materials(Ukrainian State University of Chemical Technology, Dnipro, 2023) Sybir, A. V.; Hubynskyi, Semen M.; Fedorov, S. S.; Sukhyy, Kostyantyn M.; Hubynskyi, M. V.; Vvedenska, T. Y.ENG: The purpose of the study was to determine the influence of the main following factors on the efficiency of the process of high-temperature refining of natural and artificial graphite: processing temperature, distribution of metal oxides, and changes in the aggregate state of ash impurities. Thermal processing of natural graphite from Ukrainian deposits and anthracite from Donetsk coal basin was carried out in a chamber furnace at a holding time of 10–20 minutes in a temperature range of 1500–30000 Ñ. The quality of refining was carried out by ICP-OES and XRF analysis methods. It was established that the refining process may be divided into three following periods: 0–16000 Ñ (removal of moisture, volatiles, and decomposition of carbonates); 1600–26000 Ñ (evaporation of main ash-forming metals Fe, Si, Al, Ca, Mg in the form of oxides, silicides, and carbides); and 2600–30000 Ñ (evaporation of refractory compounds Ti, V, Mo, the content of which in the initial raw material determines the processing temperature and the quality of the final product). The distribution of metal oxides in the initial carbon material is not uniform, which complicates the use of equilibrium state models. The transition of ash into the liquid and then gaseous state has a significant impact on the result of heat treatment. This is what determines the choice of the process scheme. Intermittent process is the heating by an external heater in an inert gas environment. Continuous process is the heating of the material in moving containers or processing in an electrothermal fluidized bed.Item Prediction of Atmospheric Air Pollution Near a Coal Stack in Adverse Weather Conditions(IOP Publishing Ltd, 2023) Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Nochvai, Volodymyr; Yakubovska, Zinaida M.; Oladipo, Mutiu OlatoyeENG: Coal piles on the territory of enterprises are long-term sources of dust pollution of atmospheric air. Forecasting the level of dust pollution of the air for such objects is carried out, as a rule, for convection conditions. But during inversion, very high concentrations of dust can occur on industrial sites. The task of assessing the level of dust pollution of atmospheric air at an industrial site during dust emission in conditions of inversion from a coal stack is considered. A three-dimensional equation of convective-diffusion dispersion of contamination in atmospheric air, compatible with the approach of Prof. Berliand M. on determining the value of the vertical diffusion coefficient in the surface layer of the atmosphere for the case of inversion, to model dispersion of dust from a coal stack under inversion conditions is used. Numerical integration of the modeling equation of convective-diffusion transport of contamination is carried out on the basis of the splitting method compatible with the use of a locally one-dimensional finite-difference scheme. The results of a computational experiment to determine dust pollution zones at the Prydniprovsk thermal power station are presented.Item Quick computing CFD model to predict chemical pollution in room(Український державний університет науки і технологій, Дніпро, 2025) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Mashykhina, Polina B.ENG: Purpose. The problem of accidental contamination of workspaces attracts special attention, since in the event of such extreme situations, intense chemical contamination of the air in work areas occurs. This poses a threat of toxic exposure to workers. When assessing the consequences of such situations, it is necessary to take into account the time factor, in particular, to quickly determine the creation of concentrations of chemically hazardous substances. In this regard, an urgent task is to develop effective mathematical models for rapid assessment of the consequences of extreme situations in the working areas of chemically hazardous facilities. The paper considers a CFD model for analyzing the process of chemical air pollution in a workspace during an accidental release of a chemically hazardous substance. The solution of the problem is based on the numerical integration of the fundamental equations of continuum mechanics. Methodology. To calculate the air velocity field in the working room during the operation of supply and exhaust ventilation, a mathematical model of the motion of an inviscid fluid was used. The equation of convective diffusion motion was used to calculate the concentration of a chemically hazardous substance in the workspace. The integration of the modeling equations was carried out using finite difference schemes. Findings. A dynamic model has been created to calculate the spread of a chemically hazardous substance in a work-space. On the basis of the built CFD model, a computer program was created to conduct a computational experiment. Originality. A CFD model has been created to predict the level of air pollution in a workspace in the event of toxic gas emissions. The model is based on the fundamental equations of aerodynamic mechanics and mass transfer. The model makes it possible to determine the effect of the ventilation mode, the intensity of emission of a chemically hazardous substance, the location of equipment in the workspace, and the dynamics of the formation of concentration fields. Practical value. The developed CFD model can be used to quickly analyze the consequences of accidental emissions of a chemically hazardous substance in a workplace and assess the risk of toxic exposure of workers.Item Structurally Dependent Electrochemical Properties of Ultrafine Superparamagnetic ‘Core/Shell’ γ-Fe2O3/Defective α-Fe2O3 Composites in Hybrid Supercapacitors(MDPI, Switzerland, 2021) Bazaluk, Oleg; Hrubiak, Andrii; Moklyak, Volodymyr; Moklyak, Maria; Kieush, Lina; Rachiy, Bogdan; Gasyuk, Ivan; Yavorskyi, Yurii; Koveria, Andrii; Lozynskyi, Vasyl; Fedorov, SerhiiENG: The paper presents a method for obtaining electrochemically active ultrafine composites of iron oxides, superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3, which involved modifying sol-gel citrate synthesis, hydrothermal treatment of the formed sol, and subsequent annealing of materials in the air. The synthesized materials’ phase composition, magnetic microstructure, and structural, morphological characteristics have been determined via X-ray analysis, Mossbauer spectroscopy, scanning electron microscopy (SEM), and adsorption porometry. The mechanisms of phase stability were analyzed, and the model was suggested as FeOOH – γ-Fe2O3 – α-Fe2O3. It was found that the presence of chelating agents in hydrothermal synthesis encapsulated the nucleus of the new phase in the reactor and interfered with the direct processes of recrystallization of the structure with the subsequent formation of the α-Fe2O3 crystalline phase. Additionally, the conductive properties of the synthesized materials were determined by impedance spectroscopy. The electrochemical activity of the synthesized materials was evaluated by the method of cyclic voltammetry using a three-electrode cell in a 3.5 M aqueous solution of KOH. For the ultrafine superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O composite with defective hematite structure and the presence of ultra-dispersed maghemite with particles in the superparamagnetic state was fixed increased electrochemical activity, and specific discharge capacity of the material is 177 F/g with a Coulomb efficiency of 85%. The prototypes of hybrid supercapacitor with work electrodes based on ultrafine composites superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3 have a specific discharge capacity of 124 F/g with a Coulomb efficiency of 93% for current 10 mA.Item Structurally Dependent Electrochemical Properties of Ultrafine Superparamagnetic ‘Core/Shell’ γ-Fe2O3/Defective α-Fe2O3 Composites in Hybrid Supercapacitors(MDPI, Switzerland, 2021) Bazaluk, Oleg; Hrubiak, Andrii; Moklyak, Volodymyr; Moklyak, Maria; Kieush, Lina; Rachiy, Bogdan; Gasyuk, Ivan; Yavorskyi, Yurii; Koveria, Andrii; Lozynskyi, Vasyl; Fedorov, SerhiiENG: The paper presents a method for obtaining electrochemically active ultrafine composites of iron oxides, superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3, which involved modifying sol-gel citrate synthesis, hydrothermal treatment of the formed sol, and subsequent annealing of materials in the air. The synthesized materials’ phase composition, magnetic microstructure, and structural, morphological characteristics have been determined via X-ray analysis, Mossbauer spectroscopy, scanning electron microscopy (SEM), and adsorption porometry. The mechanisms of phase stability were analyzed, and the model was suggested as FeOOH → γ-Fe2O3 → α-Fe2O3. It was found that the presence of chelating agents in hydrothermal synthesis encapsulated the nucleus of the new phase in the reactor and interfered with the direct processes of recrystallization of the structure with the subsequent formation of the α-Fe2O3 crystalline phase. Additionally, the conductive properties of the synthesized materials were determined by impedance spectroscopy. The electrochemical activity of the synthesized materials was evaluated by the method of cyclic voltammetry using a three-electrode cell in a 3.5 M aqueous solution of KOH. For the ultrafine superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O composite with defective hematite structure and the presence of ultra-dispersed maghemite with particles in the superparamagnetic state was fixed increased electrochemical activity, and specific discharge capacity of the material is 177 F/g with a Coulomb efficiency of 85%. The prototypes of hybrid supercapacitor with work electrodes based on ultrafine composites superparamagnetic ‘core/shell’ γ-Fe2O3/defective α-Fe2O3 have a specific discharge capacity of 124 F/g with a Coulomb efficiency of 93% for current 10 mA. View Full-Text.Item Study of Cellulose Additive Effect on the Caking Properties of Coal(Dnipro University of Technology, Dnipro, Ukraine, 2023) Koveria, Andrii; Kieush, Lina; Usenko, Andrii Yu.; Sova, ArtemENG: Purpose. The work aims to study the effect of cellulose on the caking properties of various types of coking coal used in coking blends. The change in caking abilities has been analyzed to achieve the aim using standard techniques. At the same time, the effect of biomass additives on the plastic properties of coal has been analyzed comprehensively; the optimal amount of additive for practical purposes has been determined. Methods. Multiple coal characteristics in the plastic stage have been studied using a dilatometric method, the enhanced swelling pressure method, the plastometric method, and the Roga index test. The first three methods make it possible to characterize the caking properties of coal; and the Roga index test characterizes its coking ability. Findings. It has been identified that the optimal amount of biomass additive to study the effect on the properties of coal in the plastic state is more than 5 wt. %. In the paper, experimental dependences of the 5 wt. % cellulose addition influence on the caking properties of four coal grades have been obtained. The results showed a slight decrease in caking properties in terms of swelling, swelling pressure, thickness of the plastic layer, and caking ability. Simultaneously, the most sensitive methods for assessing the effect of cellulose addition on the coal plastic properties are the dilatometric method as well as the enhanced method for the swelling pressure determination. Originality. A comprehensive study of the effect of pure cellulose as a component of lignocellulose biomass on the properties of different coal grades in the plastic state (i.e. caking prperteis) has been carried out. A slight change in the coal properties in the plastic state with adding 5 wt. % cellulose, decreasing caking properties, has been shown. An important, not previously reported, conclusion is that the cellulose additive does not have any noticeable effect on the physical properties of the coal charge owing to its loose structure. Practical implications. A slight change in the caking properties of coal has been established with the addition of 5 wt. % which is of practical importance for the preparation of coal blends, and the coke production in the cases of using additives of lignocellulosic biomass without losing its quality. Additionally, renewable additive use while obtaining fuels and reducing agents is an approach to mitigate the negative environmental impact.Item Визначення механічних властивостей синтетичних чавунів при використанні карбюризаторів отриманих на основі електротермічного киплячого шару(Інститут чорної металургії ім. З. І. Некрасова НАН України, Дніпро, 2024) Губинський, Михайло Володимирович; Меркулов, Олексій Євгенович; Сибір, Артем Віталійович; Федоров, Сергій Сергійович; Губинський, Семен Михайлович; Форись, Олексій Михайлович; Дудченко, Сергій Олександрович; Джигота, Марина ГеоргіївнаUKR: Розвиток високотемпературних технологій у металургії та хімічній галузі пов’язаний з заміною викопних видів палива на зелену електроенергію. Саме таку можливість має процес нагріву вуглецевої сировини у електротермічному киплячому шарі (ЕКШ) коли струм проходить безпосередньо через шар і нагріває його за рахунок джоулевої теплоти. Такий процес дозволяє значно зменшити витрати енергії порівняно з традиційними технологіями, що базуються на використанні печей Аченсона та Кастнера. Одним з продуктів що може бути отриманий в печах ЕКШ є карбюризатори що використаються при виплавці синтетичного чавуну. Проведені дослідження дозволили визначити властивості до карбюризаторів, що забезпечують якість чавунів та параметри термічної обробки прекурсорів у ЕКШ. Метою даного дослідження було отримання прямої відповіді про ефективність карбюризаторів отриманих за новою технологією. Вирішення цього завдання проведено шляхом порівняльних випробувань карбюризаторів отриманих методом ЕКШ та традиційними технологіями при отриманні синтетичного чавуну. Випробування проведені з використанням лабораторної індукційної печі ємністю 10 кг. Плавки було проведено в ідентичних умовах. В результаті доведено що процеси навуглецювання чавуну з карбюризатором отриманим по новій технології та синтетичним графітом мають східні температурні та кінетичні залежності. Ступінь засвоєння вуглецю практично однакові. Металографічний аналіз отриманих зразків синтетичного чавуну показав, що виливки отримані з використанням синтетичного графіту характеризуються більшою кількістю пор, що може бути причиною зниження механічних властивостей. Результати випробувань на стиск, розтягнення, вигин та твердість підтвердили це. Отримані результати випробувань довели ефективність вироблення карбюризаторів високої якості з використанням технології ЕКШ.Item Вуглецевотермічне відновлення оксидів заліза в умовах електромагнітного впливу(НМетАУ, УДУНТ, Дніпро, 2024) Гришин, Олександр Михайлович; Величко, Олександр Григорович; Грек, Олександр Сергійович; Надточій Анжела АнатоліївнаUKR: Мета. З метою отримання кількісних характеристик впливу електромагнітного поля на процес відновлення оксидів заліза вуглецем у твердій фазі та вивчення механізму цього процесу проведено експериментальні дослідження вуглецевотермічного та комплексного відновлення заліза з гематиту, магнетиту та окалини. Методика. Експерименти проводили у змінному магнітному полі індукційної печі з частотою змінного току в індукторі від 50 Гц до 40 кГц. з використанням термогравіметричної методики. Процес відновлення моделювали в умовах вуглецевотермічного відновлення із визначенням кінцевого ступеню відновлення оксиду та часу відновлення у діапазоні температур 973-1373 К з використанням різних рудо-вугільних матеріалів. Результати. Отримані дані свідчать про прискорення процесів газифікації вуглецю та газового відновлення оксидів під впливом ЕМП на 10-20 %. Встановлено що вплив магнітного поля тим вищий чим вище частота змінного струму в індукторі печі а також що вплив магнітного поля вищий у низькотемпературних діапазонах відновлення. Наукова новизна. Експериментально підтверджено вплив ЕМП на кінетику відновлення оксидів заліза. Запропоновано механізм впливу поля що інтенсифікує процес відновлення заліза. Практична значущість. Інтенсифікація процесів вуглецевотермічного відновлення оксидів заліза забезпечує зниження енерговитрат та підвищення продуктивності процесу.Item Дослідження ефективності використання захисних екранів різної форми для зниження забруднення повітря(Придніпровська державна академія будівництва та архітектури, Дніпро, 2023) Біляєв, Микола Миколайович; Берлов, Олександр Вікторович; Біляєва, Вікторія Віталіївна; Козачина, Віталій Анатолійович; Якубовська, З. М.UKR: Постановка проблеми. Розглядається задача оцінювання ефективності використання захисних екранів різної геометричної форми для зниження рівня забруднення повітря. Такі екрани дозволяють змінити аеродинаміку повітряного потоку та перенаправити рух забрудненого повітря від робочих зон в інший бік. Мета роботи − дослідження ефективності використання захисних екранів різної геометричної форми для зниження рівня забруднення, створення тривимірної числової моделі для аналізу ефективності використання захисних екранів. Методика. Для аналізу ефективності екранів різної геометричної форми застосовується метод фізичного експерименту в лабораторних умовах. Для математичного моделювання поширення домішки за наявності екранів використовуються тривимірні рівняння аеродинаміки та масопереносу. Розроблена числова модель дозволяє врахувати профіль швидкості повітряного потоку, атмосферну дифузію, інтенсивність емісії домішки, швидкість гравітаційного осадження домішки в повітрі. Для числового інтегрування моделювальних рівнянь аеродинаміки та масопереносу використовуються скінченнорізницеві схеми розщеплення. Наукова новизна. Експериментальним шляхом отримано дані щодо ефективності використання чотирьох захисних екранів, які відрізняються геометричною формою. Експериментальні дані дають можливість здійснити первинне оцінювання впливу різних екранів на зниження рівня забруднення в робочих зонах. Розроблена швидкорозрахункова 3D числова модель для розв’язання задач аеродинаміки та масопереносу стосовно проблеми оцінювання ефективності використання екранів у зонах, де має місце забруднення атмосферного повітря. Практична значимість. Експериментальні дані дають можливість обґрунтувати вибір захисного екрана біля автотраси або іншої ділянки на промисловому майданчику, де має місце емісія домішки. На базі розробленої математичної моделі створено комп’ютерний код, що дозволяє прогнозувати інтенсивність забруднення повітря за наявності перешкод, які змінюють аеродинаміку та напрям переносу домішки в атмосфері. Висновки. Результати фізичного експерименту дозволяють уявити закономірності формування областей забруднення біля захисних екранів різної геометричної форми. Розроблена математична модель дозволяє оцінювати забруднення повітря в областях, де є перешкоди на шляху руху домішки. Наведено результати фізичного та обчислювального експериментів.
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