Кафедра енергетичних систем та енергоменеджменту (ДМетІ)

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UK: Кафедра енергетичних систем та енергоменеджменту (Дніпровський металургійний інститут) EN: Department of Energy Systems and Energy Management (DMetI)

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Analysis of Air Dust Pollution in the Transport Compartment of the Launch Vehicle at the Stage of the Pre-launch Preparation
(Printing House “Technologija”, Kaunas, Lithuania, 2024) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.; Mashykhina, Polina B.; Semenenko, Pavlo
ENG: At the stage of the pre-launch preparation, it is necessary to fulfill very strict environment conditions inside the main fairing where the satellite is located. Namely, it is very important to predict dust concentration inside the main fairing and especially near satellite surface during forced ventilation. To predict air dust pollution inside of main fairing 2D fluid dynamics numerical model has been developed. The governing equations include equation of potential flow to simulate air flow inside the main fairing and equation of pollutant dispersion. Also, empirical model has been used to calculate the number of dust particles fall to the satellite surface. Implicit finite difference schemes of splitting have been used for numerical integration of governing equations. The computer code has been developed on the basis of proposed numerical model. The results of computational experiments to estimate dust concentration field inside the main fairing of the launch vehicle are presented.
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 S.; Usenko, Andrii Yu.; Hubynskyi, Mykhailo V.; Vvedenska, Tetyana
ENG: 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.
Application of Biomass Pellets for Iron Ore Sintering
(Trans Tech Publications Ltd, Switzerland, 2021) Kieush, Lina; Koveria, Andrii; Qiao Zhu, Zuo; Boyko, Maksym M.; Sova, Artem; Yefimenko, Vadym
ENG: Purpose. The use of biomass as fuel might solve several technological and environmental issues and overcome certain challenges of sinter production. In particular, as revealed by comprehensive analyses, biomass can be used as fuel for iron ore sintering. In this study, we investigate the use of some raw and pyrolysis-processed biomass pellet types, namely wood, sunflower husks (SFH), and straw, for iron ore sintering. In the experiments, the pyrolysis temperature was set to 673, 873, 1073, and 1273 K, and the proportion of biomass in the fuel composition was set to 25%. It was established that the addition of biofuels to the sintering blend leads to an increase in the gas permeability of the sintered layer. The analysis of the complex characteristics of the sintering process and the sinter strength showed the high potential of wood and sunflower husk pellets pyrolyzed at 1073 and 873 K, respectively, for iron ore sintering. The analysis of the macrostructure of the sinter samples obtained using biomaterials revealed that with higher pyrolysis temperatures; the materials tend to have greater sizes and higher amounts of pores and cracks. The composition analyses of the resultant sinters revealed that with higher temperature, the FeO content of the sinters tends to increase.
CFD Modeling of Traffic-related Air Pollution in Street Canyon
(Printing House “Technologija”, Kaunas, Lithuania, 2024) Biliaiev, Mykola M.; Biliaieva, Viktoriia V.; Berlov, Oleksandr V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia V.; Yakubovska, Zinaida M.
ENG: High pollution levels are often observed in urban street canyons. Different mathematical models are intensively used to predict pollution levels in urban street canyons. In this paper quick computing 3D CFD model is proposed to compute wind flow over buildings and pollutant dispersion in street canyon. To simulate wind flow over buildings 3D equation of potential flow has been used. Pollutant concentration field has been modelled using three-dimensional equation of pollutant dispersion. Governing equations are also included simplified equations to describe pollutants chemical transformations in atmosphere. To solve numerically governing equations implicit difference schemes have been used. The computer code to realize the proposed numerical models has been developed. Results of numerical experiments are presented.
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.
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, Serhii 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.
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.
Energy Efficient Water-Cooled Elements for Foundry Class Electric Arc Steelmaking Furnaces
(НМетАУ, Дніпро, 2021) Timoshenko, Sergii; Nemtsev, Eduard; Gubinskij, Mikhail
ENG: 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.
Energy-Efficient Solutions of Foundry Class Steelmaking Electric Arc Furnace
(Dnipro University of Technology, Dnipro, 2021) Timoshenko, S. M.; Gubinski, M. V.; Niemtsev, E. M.
ENG: Purpose. Substantiation of solutions aimed at reducing heat losses, mainly, by refractory lining during forced downtime and by steelmaking bath in conditions of traditionally low specific power of transformer. Methodology. Mathematical modeling of heat and mass transfer processes and numerical experiment. Findings. A mathematical model of energy-technological processes in arc furnace workspace has been developed to analyze and minimize energy consumption in daily production cycle. Geometrical and operating parameters are taken into account, in particular: variation in arcs energy efficiency at evolution of wells in charge under electrodes during melting process; circulation of melt due to bubbling with inert gas through bottom porous plug; energy loss on heat accumulation by refractory, with cooling water and off-gas. Originality. For the first time, the concept of increasing energy efficiency of arc furnace has been substantiated, based on the following set of solutions: increase in specific electrical power by reducing of charge at given productivity; reduction of bath shape factor (ratio of diameter to depth) from traditional 5 up to 2.5 by deepening and, accordingly, its radiating surface; optimization of walls and roof cooled surface relative area, where massive heat-absorbing refractory lining is not used; application of energy-saving water-cooled elements with spatial structure that promotes formation of heat-insulating and heat-accumulating slag filling. Practical value. Implementation of the set of energy-efficient solutions in conditions of typical 6 and 12-t foundry class arc furnaces provides reduction in power consumption and refractory expenditure by 1315 and 2830% respectively without significant changes in production infrastructure due to reducing energy loss, mainly, for accumulation of heat by refractory lining, and intensification of heat and mass transfer processes in forcibly stirred deep bath.
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.
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, Oleg
ENG: 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.
Influence of Biocoke on Iron Ore Sintering Performance and Strength Properties of Sinter
(Dnipro University of Technology, Dnipro, Ukraine, 2022) Kieush, Lina; Koveria, Andrii; Boyko, Maksym M.; Yaholnyk, Maksym V.; Hrubiak, Andrii; Molchanov, Lavr; Moklyak, Volodymyr
ENG: Purpose. The research purpose is to substantiate the use of biocoke as a fuel in the iron ore sintering, as well as its influence on the performance and properties of the resulting sinter. To completely replace conventional coke breeze, biocoke is produced using 5 wt.% biomass wood pellets at different carbonization temperatures of 950 or 1100°C. Further, the influence of biocoke on the sintering process and the sinter quality is studied at a high proportion of biomass pellets of 10, 15, 30, 45 wt.% and a carbonization temperature of 950°C. Methods. Carbonization is performed in shaft-type electric furnaces to produce laboratory coke or biocoke. Afterward, the sintering of iron ores is conducted on a sinter plant. To assess the sintering process and the quality of the resulting sinter, the filtration rate is determined on a laboratory sinter plant using a vane anemometer designed to measure the directional flow average velocity under industrial conditions. The sinter reducibility is studied using a vertical heating furnace to assess the effect of coke and biocoke on the sinter’s physical-chemical properties. Findings. It has been determined that biocoke, carbonized at a temperature of 950°C, has good prospects and potential for a shift to a sustainable process of iron ore sintering. Originality. It has been proven that biocoke with a biomass pellet ratio of up to 15 wt.%, obtained at a temperature of 950°C, does not affect the parameters characterizing the sintering process. The sinter strength indicators correspond to the use of 100 wt.% conventional coke breeze. Biocoke used with a high proportion of biomass pellets of 30 and 45 wt.% causes a deterioration in the sinter quality. Practical implications. The results of using biocoke with the addition of 5-15 wt.% biomass pellets and at a temperature of 950°C are within the standard deviation, which makes it possible to use biocoke with 15 wt.% biomass pellets instead of industrial coke breeze.
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.
Metallurgical Coke Production with Biomass Additives: Study of Biocoke Properties for Blast Furnace and Submerged
(MDPI, Switzerland, 2022) Bazaluk, Oleg; Kieush, Lina; Koveria, Andrii; Schenk, Johannes; Pfeiffer, Andreas; Zheng, Heng; Lozynskyi, Vasyl
ENG: Biocoke has the potential to reduce the fossil-based materials in metallurgical processes, along with mitigating anthropogenic CO2- and greenhouse gas (GHG) emissions. Reducing those emissions is possible by using bio-based carbon, which is CO2-neutral, as a partial replacement of fossil carbon. In this paper, the effect of adding 5, 10, 15, 30, and 45 wt.% biomass pellets on the reactivity, the physicomechanical, and electrical properties of biocoke was established to assess the possibility of using it as a fuel and reducing agent for a blast furnace (BF) or as a carbon source in a submerged arc furnace (SAF). Biocoke was obtained under laboratory conditions at final coking temperatures of 950 or 1100 °C. Research results indicate that for BF purposes, 5 wt.% biomass additives are the maximum as the reactivity increases and the strength after reaction with CO2 decreases. On the other hand, biocoke’s physicomechanical and electrical properties, obtained at a carbonization temperature of 950 °C, can be considered a promising option for the SAF.
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, Oksana
ENG: 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.
Modeling Influence of TiO2 Barrier Coating on Pollutant Dispersion Near Road
(Kaunas University of Technology, 2023) Biliaiev, Mykola M.; Berlov, Oleksandr V.; Biliaieva, Viktoriia V.; Kozachyna, Vitalii A.; Kozachyna, Valeriia; Yakubovska, Zinaida M.
ENG: Mitigation strategies for near-road air pollution are of great interest nowadays. Sound barriers near the road are very effective to decrease pollutant concentration. The use of titanium dioxide (TiO2) barrier coating provides additional effect which allows to decrease pollutant concentration near road. In this study quick- computing CFD model was developed to access influence of TiO2 barrier coating on pollutant concentration. To simulate wind flow over barrier with TiO2 coating model of potential flow was used. The process of NOx dispersion from car was computed using mass conservation equation. Finite-difference schemes were used for numerical integration of governing equations. The computer code was developed on the basis of proposed numerical model. Results of numerical simulations are presented.
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.
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, Valentyn
ENG: 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.
Peculiarities of High-Temperature Refining of Carbon Materials
(Ukrainian State University of Chemical Technology, Dnipro, 2023) Sybir, A. V.; Hubynskyi, Semen M.; Fedorov, Serhii 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.
Phenomena at Three-Phase Electroslag Remelting
(Springer Nature, 2021) Liu, Zhong-li; Medovar, Lev; Stovpchenko, Ganna; Petrenko, Volodymyr; Sybir, Artem; Volchenkov, Yev.
ENG: The electroslag remelting (ESR) process is widely used to produce high-quality ingots and billets for high-alloyed steels and alloys. Both the single-phase and three-phase alternating current diagram with bifilar and monofilar connection are in use for heavy ingot manufacturing. The numerical simulation of the three-phase bifilar circuit for the 120 t three-phase bifilar six-electrode ESR furnace at different variants of electric connection was presented and discussed. At the bifilar diagram of power supply, the geometrical location of electrodes in a mould holds critical importance for performances: the close location of bifilar pair electrodes provides the highest heat productivity, but the equidistant location of electrodes gives a much more uniform heat distribution. The monofilar mulit-electrode diagram of three-phase connection without phase shift shows the most uniform distribution of potential and heat generation as well as a favorable magnetic field that makes this kind the most promising for providing a high quality of heavy ingots.

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