Browsing by Author "Zhuravlova, Svitlana V."

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    Determining the Impact of Different Types of Biofuels on the Quality of Iron Ore Pellets
    (РС ТЕСHNOLOGY СЕNTЕR, Kharkiv, 2024) Yefimenko, Vadym; Boyko, Maxim M.; Zhuravlova, Svitlana V.; Marko, Anatolii; Tanchev, Oleksandr; Dutniy, Ruslan
    ENG: The object of this study is the process of roasting iron ore pellets. The study solves the task of replacing fossil fuel with plant-based fuel in order to reduce environmental load and ensure the stable quality of pellets, which is necessary for use in blast furnaces. The influence of biofuel content at a given temperature and air speed on the strength of pellets after roasting was studied. As a result of the research, it was established that the fuel content has a decisive effect on the strength of pellets. Among all types of fuel that were investigated, pellets with the addition of sunflower husks and wood had the highest strength that meets the requirements for blast furnace melting of 200 kilograms. The use of wheat straw and charcoal does not make it possible to completely replace solid fuel in the layer of pellets. The results show that the use of up to 0.36 % of sunflower husk makes it possible to increase the strength of burned pellets compared to samples without biofuel content. Adding all other considered types of fuel reduced the strength of the pellets. These results are explained by the different content of lignin, cellulose, and hemicellulose, which determines the characteristics of the biomass. The high content of cellulose and hemicellulose allows for high hydrophilicity due to the high number of OH groups and positively affects the formation of raw pellets. Volatile substances released during the combustion of biofuel contribute to the formation of spherical pores, as well as their uniform distribution, which prevents the propagation of cracks under load. Research results make it possible to establish the optimal roasting mode, decrease harmful emissions, and bring down costs by reducing fossil fuel consumption.
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    Investigating Cavity Formation in an Electric Arc Zone During Out-of-Furnace Processing of Steel
    (PC TECHNOLOGY CENTER, Ukraine, 2023) Ruban, Volodymyr O.; Stoianov, Oleksandr M.; Niziaiev, Kostiantyn H.; Synehin, Yevhen V.; Zhuravlova, Svitlana V.; Malii, Khrystyna V.
    ENG: The object of this study is the interaction zone between a graphitized hollow electrode (GHE) and a metal bath on the «ladle-furnace» installation. The regularities of the formation of the geometric parameters of the hole were established for the purpose of further evaluation of the heat exchange under the electrode in the arc combustion zone under different operating conditions of the «ladle-furnace» installation. An experimental methodology was devised, and a laboratory setup was built for physical simulation on a cold model. The values of the geometric parameters of the cavity formed by the electric arc discharge in the sub-electrode zone were calculated. In particular, the area of the curved surface of the cavity is about 0.2 m2 at a depth of 40 mm. The regularities of formation of the geometry of the cavity during gas injection through the GHE channel have been established, in particular with regard to the area and depth of the cavity. Thus, with a gas consumption of 3–20 m3/h and a slag cover height of 100 mm, the area reaches 0.28–0.5 m2, while the depth of the cavity ranged from 5 cm to 19 cm, respectively. Rational flow rates of gas supplied through the channel of the graphitized hollow electrode were established, which for a slag cover of 100 mm are 3–6 m3/h and for a slag cover of 200 mm – 6–10 m3/h. The peculiarities of the formation of a metal cavity in the sub-electrode zone under the conditions of gas supply through the channel of a graphitized hollow electrode during out-of-furnace processing of steel at the «ladle-furnace» installation were investigated. The patterns of the formation of the geometry of the cavity in the arc combustion zone, which were obtained using cold modeling, could subsequently make it possible to perform calculations of heat transfer from the electric arc discharge to the metal bath. That will also make it possible to determine the share of heat absorbed by slag and metal under the conditions of using a conventional electrode, and a hollow one with gas supply through its channel during out-of-furnace processing of steel at the «ladle-furnace» installation.