Metallurgical Furnaces Research Articles

Burner development for efficient combustion of biogas

Now in metallurgical production energy resources demand is almost completely satisfied by gaseous fuel. Biogas obtained during organic waste processing is considered as an alternative and cheaper type of fuel. The experience of biogas application has shown that in most modern burners decrease of efficiency and limitation of the range of load regulation is observed. To apply biogas in an industrial environment, it is necessary to develop burners and the methods of its combustion, which provide a high combustion efficiency, as well as a higher energy conversion efficiency. The authors have used the results of gas analysis of biogas obtained in the process of anaerobic decomposition process of organic waste in the reactors of a bioenergy plant. Methods of mathematical statistics with the use of regression analysis of experimental data were used to assess the indicators of the energy efficiency of the gas burner. The possibility of using biogas and landfill gas in the process of roasting, blast-furnace smelting, production of rolled products and steel, as well as heat treatment of metal has been experimentally proven. The properties and composition of biogas at the outlet of the methanogenesis reactor of the bioenergy plant “EcoVoltAgro” are described. A new design of a gas burner is proposed. In this model the efficiency of mixture formation and the completeness of combustion of the flow of a methane-containing gas mixture are significantly increased (up to 32 %) due to the effect of rotation of the perforated pipelines of the gas inlet pipe. On the basis of the results of the full-scale experiment, the optimal values of the gas-air mixture supply rate, the temperature of the supplied air, the volume fraction of methane were determined in order to obtain the largest width of the zone of deviations of the permissible concentrations of carbon dioxide. The use of the designed gas burner provides energy-efficient combustion of biogas in metallurgical furnaces, kilns, and dryers, as well as in any steam and hot water boilers.

Los Hornos de reverbero andinos

Bringing together information from colonial-era historical sources, archaeological data, and the results of archaeological experimentation, this work addresses reverberation furnaces, a kind of metallurgical furnace used in the southern Andes from the first moments of Spanish colonial efforts to produce silver in the region. Evidence of this three-chamber oven (composed of a fire chamber, vaulted work chamber, and chimney), has been identified and studied in different mining and metallurgical contexts in the south of Bolivia (Potosí, Santa Isabel, Mina Santiago, Escoriani, among others). Here, we show the continuities between pre-Hispanic metallurgy and reverbation furnaces. We challenge the general characterization of these furnaces as a European tradition, and propose instead that they were the result of local technological developments and later spread throughout Europe.

Simulation of the electromagnetic processes in a metallurgical furnace with two bottom electrodes

The paper presented electromagnetic processes occurring in an ore reduction furnace with two bottom electrodes. The physical and mathematical formulations of the problem are given, as well as the methodology and algorithm for the numerical simulation of the problem.

Hot Chlorination Corrosion of Metallic Nickel by Chlorine Catalyzed by Sodium Chloride.

Reducing chlorine corrosion to metals at high temperatures is a big problem for many industrial processes. Some high Ni alloys such as Hastelloy C-276 (Ni > 50 wt %) have been widely used for this purpose. Chlorine and chlorides often coexisted in many industrial processes at high temperatures, such as some industrial incinerators and metallurgical furnaces. Thus, a comprehensive experimental investigation regarding the effect of NaCl on the chlorination corrosion of metallic nickel powder by chlorine at a high temperature was performed. It was more convenient to investigate the intrinsic chlorination mechanisms and kinetics of metallic Ni if Ni powder was used instead of a Ni plate. It was found that there existed a critical chlorination temperature of 450 °C for relative safe use of Ni-based alloy in the presence NaCl. The Ni chlorination in the presence of NaCl was increased with increasing temperature and reached a maximum of 97% at 700 °C, which was about 21% higher than that in the absence of NaCl. An anhydrous NiCl2 was initially formed at about 700 °C during the chlorination process and then immediately reacted with NaCl to form a novel eutectic complex with a flaky shape, a melting point of 585 °C, and a simplified molecular formula of NiNa0.33Cl2.33 based on X-ray diffraction (XRD), differential thermal analysis (DTA), scanning electronic microscopy (SEM), and chemical analysis with inductively coupled plasma atomic emission spectroscopy (ICP-AES). As a result, only the complex of NiNa0.33Cl2.33 and NaCl was left in the chlorinated product. At 700 °C, the chlorinated product evaporated only in the form of complex NiNa0.33Cl2.33 instead of individual NiCl2 or NaCl. The chlorination mechanisms of metallic Ni at a high temperature, for example, 700 °C, in the presence of NaCl were as follows. Step 1: Formation of initial chlorinated solid product NiCl2 (mp 1001 °C) at a high temperature; step 2: The NiCl2 reacted with solid additive NaCl (mp 801 °C) to form a final liquid product NiNa0.33Cl2.33 (mp 585 °C); step 3: External Cl2(g) was dissolved in the liquid product layer; step 4: The chlorine dissolved in the liquid product of NiNa0.33Cl2.33 reacted with the unreacted Ni core. The external Cl2(g) passed through the liquid product NiNa0.33Cl2.33 layer faster than the solid product NiCl2 layer formed in the absence of NaCl. This resulted in 21% more chlorination corrosion of metallic Ni powder with NaCl addition than that without NaCl addition.

The effect of heat treatment temperature on the resistance to intergranular corrosion of welded joints of heat-resistant nickel alloys inconel 718 and steel 316l

The effect of heat treatment temperature on the resistance to intergranular corrosion of welded joints of heat-resistant nickel alloys inconel 718 and steel 316l

Assessing the Potential Application of Geophagic Materials as Refractory for Metallurgical Furnace Lining

Assessing the Potential Application of Geophagic Materials as Refractory for Metallurgical Furnace Lining

Theory and Practice of Heat Transfer in Electric Arc Steelmaking and Flare Metallurgical Furnaces and Power Plants

The author describes the fundamental laws of physics, the laws of thermal radiation of ionized and non-ionized gas volumes. Based on open laws, a modern theory of heat transfer and methods for calculating heat transfer in electric arc and flare metallurgical furnaces, furnaces of steam boilers, and combustion chambers of gas turbine plants of power plants have been developed. The use of scientific discovery makes it possible to create innovative electric arc steel-smelting furnaces, flare heating furnaces, and combustion chambers in which the consumption of electricity and fuel is reduced, productivity and service life are increased, and the amount of harmful emissions into the environment is reduced.

EXPLORATION OF THE OLD RUS’ RURAL CRAFT AND LIVING SETTLEMENTS IN KYIV REGION ON THE RIGHT BANK OF DNIEPER

In 2017 the archaeological exploration in the zone of construction of the transmission line in the Makariv district of Kyiv region took place. Three sites — Nalyvaikivka 1 (second half of the 10th — 11th, 12th—13th centuries), Farm 2 (2nd—1st millennium BC) and Farm 3 (11th century) were excavated. The total area of excavation was 165 m2.
 The settlement Nalyvaykivka 1 is located in the area with high wetlands and had the necessary conditions for the extraction of iron and forestry — extraction of tar, charcoal and harvesting. The site Nalivaykivka 1 was the Medieval industrial rural settlements.
 The site Nalyvaykivka 1 contains a lot of artifacts related to iron production. They represent the different stages of the metallurgical process. Fragments of furnace for iron production have been found. The specific design of the metallurgical furnace was ascertained.
 The location near ore deposits (the iron-mining center in the Kolonshchyna region) and near the powerful product market (Kyiv) led to the craft character of the settlement. Probably it was part of the group of settlements pecialized in the production and primary processing of iron.
 The materials of the Ferma 3 settlement confirm the high economic level of the rural district of Kyiv region in comparison with the material culture of the Old Rus cities. There were no any archaeological objects excavated at the settlement. But in the cultural layer the interesting finds were recorded: the bi-conical shape whorl made of pink shale; the small iron knife with a straight back, the blade separated from the shank ledge; the anvil (?) will slip; the iron arrowhead with broken edge; iron bits; bronze vessel; metallurgical slag; shale fragment of pink; iron awl. The presence of Byzantine amphorae, glass bracelets, bronze vessels, items of military or hunting equipment testifies to the active trade and craft relations of rural and urban population of Kyiv Rus.

Comparison of argon injection and other methods of electrovortex flow control in metallurgical furnaces

The article considers the problem of modeling the metal melting in a direct current arc furnace with the bottom electrode. A mathematical model and a technique for conducting coupled modeling of magnetohydro- and thermodynamic flows in such a furnace are presented taking into account electromagnetic forces and convection. Using the developed strategy, simulations were performed and the effectiveness of some approaches to the vortex flow control was evaluated. As a result, it was shown that changing the location, shape, and temperature of the bottom electrode as well as the bottom position can significantly reduce fettle wearing near the electrode, while argon injection does not decrease shear stress and does a negative influence on the fettle.

Influence of joule heat and heat of electric arc on the vortex flow in DC arc furnace

The paper devoted to the numerical simulation of processes in DC electric arc furnaces with the bottom electrode. These furnaces have shown higher efficiency, low heat loss, lower components wear and higher quality of steel production. The biggest disadvantage of such furnaces is a high rate of fettle wear near the bottom electrode that connected with electrovortex flow. Electrovortex flows appearing under electromagnetic forces as a result of non-homogeneous distribution of the current density through the liquid conductor. This effect can be observed in many technological processes: electro slag remelting process (including DC and AC metallurgical furnaces, electrolysis cells and submerged-resistor induction furnaces), arc welding, processes of semiconductor crystals growing, electro vortex engines etc.

Theory and Practice of Heat Transfer in Electric Arc and Flare Furnaces and Power Plants

The author describes the fundamental laws of physics, the laws of thermal radiation of ionized and non-ionized gas volumes. Based on open laws, a modern theory of heat transfer and methods for calculating heat transfer in electric arc and flare metallurgical furnaces, furnaces of steam boilers, and combustion chambers of gas turbine plants of power plants have been developed. The use of scientific discovery makes it possible to create innovative electric arc steel-smelting furnaces, flare heating furnaces, and combustion chambers in which the consumption of electricity and fuel is reduced, productivity and service life are increased, and the amount of harmful emissions into the environment is reduced.

DEVELOPMENT OF A COMPUTER SYSTEM FOR RESEARCHING THE HEAT MODE OF A CHAMBER FURNACE USING SPA TECHNOLOGY

Construction of metallurgical furnaces is impossible without their preliminary calculation. The calculation allows to analyze the influence of various factors on the processes and to choose based on this the optimal values of the parameters. There are several techniques for calculating furnaces. They are all complex enough, saturated with lots of relevant equations, reference tables, diagrams and more. Usually, they are performed manually by heating engineers, take a fair amount of time, do not always produce reliable results and require extensive engineering qualification.The purpose of this work is to create a software that automates the calculation and allows to simulate the thermal regime of a fixed kiln chamber furnace, given the limited availability of such product in the software market.To accomplish this task, Single Page Application technology, JavaScript programming language, and Angular framework were chosen.The results of the application implementation are divided into eight sections: calculation of fuel combustion; determining the size of the working space of the furnace; calculation of heat exchange in the working space of the furnace; calculation of metal heating; mode of metal heating; thermal balance of the furnace; power and efficiency of the furnace; determining the size of flue ducts.As a result of the work, the calculation of the fixed kiln chamber furnace is automated; the original design, intuitive user interface and logo of the web application are developed using modern technologies and approaches; the software is tested on concrete use cases; a test calculation and the thermal regime simulation of a fixed kiln chamber furnace is performed.

Technological Processes of Receiving Metals in The Conditions of Moderate Temperatures

In article questions of physical and chemical transformations of starting materials at their heating in metallurgical furnaces are considered. It first of all moisture evaporation, dissociation of the difficult connections, oxidizing and recovery processes, formation of fusible eutectics. An attention to interaction of oxides and sulfides with formation of the new connections having smaller melting point than initial components. It is shown that these connections are the beginning of formation of melts and actually define thermodynamics and kinetics of all process. Transition of firm components of fusion mixture to flux has a great influence on technological indicators of smelting of metal. Considering it, the research on establishment was conducted began courses of these of reaction and a possibility of determination of this criterion without direct the made experiments.

Metallurgical properties and furnace protection practice of different titanium-bearing burdens

ABSTRACT The excellent properties of titanium pellet Z in the blast furnace hearth protection were determined by studying the composition, metallurgical properties and a over four years period of application practice of titanium-containing pellets(C&Z) and ores (J, G&D) in a domestic blast furnace. The reduction and softening-melting properties of titanium pellet Z were better than those of titanium lump ore G, D and J, and titanium pellet C. Under the condition of a titanium load of 7–8 kg TiO2/tHM, the fuel rate, pressure drop and slag ratio of the blast furnace using titanium pellet Z were better than that for the titanium-bearing resources. Using pellet Z had an obvious effect on the decrease of the hearth temperature and sustained stability. It was concluded that pellet Z was an excellent titanium-bearing burden for both laboratory research and industrial trial.

Best available technologies of wastes processing in mining and metallurgical industries

Mining and metallurgical industries are referred to high wastes productions. To decrease the damage to environment, progressive equipment and technologies are required. It was shown, that the modern approach to the environment protection should be based on implementation best available technologies (BAT). In the elaborated industry technical information BAT reference-book for the mining and metallurgical industries recommendation presented for utilization of main technological wastes of metallurgical production. A brief review of technologies presented, implementation of which allow providing practically complete processing of non-organic wastes, arising during raw materials mining and production of them ferrous metals. To choose the methods of construction and operation wastes utilization, one should be guided by recommendations, related to the thermal sterilization technologies for organic wastes as well as recommendations for utilization of organic wastes. It was noted, that the part of BAT reference book devoted to storing and disposal of production and consumption wastes is an evidence of high level of technologies used in Russia to realize the process. It was indicated, that in the BAT reference books the foreign experience of wastes utilization was not taken into account. Besides, a possibility to sterilize the wastes by thermal method in metallurgical furnaces was not also described. As a whole the application of the information presented in the BAT reference books, will allow to guide specialists of mining and metallurgical plants to choose best available technologies of handling with production wastes.

Vacuum Distillation-Treated Spent Potlining as an Alternative Fuel for Metallurgical Furnaces

Spent potlining (SPL) is a well-known hazardous waste from primary aluminum production, and recycling it as an alternative fuel for metallurgical furnaces is a promising application. However, because of the presence of volatile fluorides and fluoride compounds, there are significant environmental concerns and practical/engineering issues. An environmentally friendly technique involving pretreatment of SPL first cut at 700°C by vacuum distillation (VDM) is proposed herein. Using this process route, volatile and leachable fluorides (NaF, LiF, and Na3AlF6) in SPL first cut samples were successfully recycled. The distillation process was found to be beneficial for improving the fixed carbon content of the samples, and the combustion characteristics of the VDM residue were superior to those of raw untreated SPL. Such VDM residue could potentially be used in metallurgical furnaces and burners, with promising applications such as partial or full replacement of coal in pulverized coal injection (PCI) systems.

Carbon Dioxide Turbine Expander Plant Producing Liquid and Gaseous Carbon Dioxide

The scheme of carbon dioxide cogeneration and trigeneration plant with the use of secondary energy resources in the form of combustion products or flue gases that enables to produce electricity, thermal energy and cold for centralized and decentralized supply of consumers simultaneously, is presented. In addition, the plant can produce liquid and gaseous carbon dioxide. The main elements of the plant are a heating unit, a turbodetander unit and a carbon dioxide unit for the production of cold, liquid and gaseous carbon dioxide. A thermodynamic calculation and a brief exergy analysis of the plant were carried out. In the proposed plant, off-gases from glassmelting, metallurgical furnaces, heat power facility and other energy facilities with a secondary energy temperature of 250–400 °C and above can be used as secondary energy resources. The heating unit of the installation has been designed to produce thermal energy for heating and hot water supply systems. The carbon dioxide unit has been designed for the production of cold, electric energy and carbon dioxide in liquid and gaseous form in order to ensure the operation of the plant and the use for commercial purposes. The cold in the plant can be obtained in two evaporators operating at different boiling temperatures. At a higher boiling point of carbon dioxide, cold is used in air conditioning systems and in centralized cooling and storage systems, while at a lower boiling point of carbon dioxide – in freezing and storage systems. For the implementation of the reverse carbon dioxide cycle, a three-stage carbon dioxide compressor with a receiver after the third stage is used. To reduce compression performance of the compressor, complete intermediate cooling of carbon dioxide between stages should be provided.

Параметрическая идентификация модели объекта управления по переходной функции работающей системы автоматического регулирования

It is known that the dynamic properties of industrial objects in control channels usually change significantly with a change in their mode of operation. Therefore, the indicators of quality of regulation with constant settings of automatic regulators also change, and, as a rule, they deteriorate during the operation of the units. In this connection, the problem arises of periodically adjusting the settings of regulators in the circuits of operating automatic control systems (ATS). This problem can be solved only by the actual dynamic parameters of the object being operated, therefore, the work considers the task of estimating these parameters, and according to the actual data of the operating closed system. In this case, a step perturbation is used either on the instructions or on the part of the regulator (on the load), the experienced reaction of the system to disturbances of any kind along the indicated channels can also be used. The control object is described by a second-order differential equation with delay. The parametric identification criterion is quadratic, either modular or minimax. The identification task is solved with the help of a program that implements the method of coordinate descent, the resulting one-dimensional minimization problems are solved with the help of a subroutine using the golden section method. For the numerical integration of the object equation, the Runge-Kutta method was used with an error proportional to the fifth power of the time step. In this paper, we tested the developed programs for parametric identification based on the experimental transient characteristics of ATS pressure in a metallurgical furnace. The numerical-analytical procedures for adjusting the regulators in the SAR by the found parameters of the control object are indicated.

KYIVAN RUS’ AND GOLDEN HORDE HORIZONS OF MEDIAEVAL VYSHHOROD (Based on Excavations in 1947)

Materials of the excavations at Vyshhorod in 1947 are analysed in the article. Materials collected during the excavations confirmed the existence of Kyiv Rus and Golden Horde horizons on the territory of the city (the objects of both periods were found at the hillfort, while the Kyiv Rus period buildings are traced in the suburbs of the city). In addition, the author clarified and re-examined the allegations established in the mid — 20th century of the existence the production workshops in this part of the city. The scholars of the mid — 20th century interpreted the excavated objects as metallurgical and pottery furnaces, or iron workshops. In the author’s opinion, those objects were dwellings and outbuildings. As we can see, different archaeological objects were investigated on the territory of Vyshhorod. The author can prove that some grounds and structures with recessed pits are dated by the end of the 10th and the 11th centuries (Building 3), some dated by the end of the 11th and the 12th centuries (Building 1, Blotch 2 and 3), and a few are dated by the second half of the 13th and the 14th centuries. (Buildings No. 5 and No. 6). Besides, some objects are dated widely from the 11th to the 13th centuries (Building 2, Pit 1 and 2). On the territory of the suburbs, a ground-based dwelling with a cellar (Building 7) of the Kyiv Rus period was excavated, as well as another object identified as an outbuilding with recessed pits (10th—12th centuries) which was destroyed by the burial grounds of the New Age.

Numerical Investigation of Desulfurization Kinetics in Gas-Stirred Ladles by a Quick Modeling Analysis Approach

A quick modeling analysis approach for predicting the slag-steel reaction and desulfurization kinetics in argon gas-stirred ladles has been developed in this study. The model consists of two uncoupled components: (i) a computational fluid dynamics (CFD) model for predicting the fluid flow and the characteristics of slag-steel interface, and (ii) a multicomponent reaction kinetics model for calculating the desulfurization evolution. The steel-slag interfacial area and mass transfer coefficients predicted by the CFD simulation are used as the processing data for the reaction model. Since the desulfurization predictions are uncoupled from the CFD simulation, the computational time of this uncoupled predictive approach is decreased by at least 100 times for each case study when compared with the CFD-reaction kinetics fully coupled model. The uncoupled modeling approach was validated by comparing the evolution of steel and slag compositions with the experimentally measured data during ladle metallurgical furnace (LMF) processing at Nucor Steel Tuscaloosa, Inc. Then, the validated approach was applied to investigate the effects of the initial steel and slag compositions, as well as different types of additions during the refining process on the desulfurization efficiency. The results revealed that the sulfur distribution ratio and the desulfurization reaction can be promoted by making Al and CaO additions during the refining process. It was also shown that by increasing the initial Al content in liquid steel, both Al oxidation and desulfurization rates rapidly increase. In addition, it was found that the variation of the initial Si content in steel has no significant influence on the desulfurization rate. Lastly, if the initial CaO content in slag is increased or the initial Al2O3 content is decreased in the fluid-slag compositional range, the desulfurization rate can be improved significantly during the LMF process.