Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 3. The picture of bath blowing at application two-level oxygen lances

2021 ◽  
Vol 77 (11) ◽  
pp. 1142-1155
Author(s):  
A. G. Chernyatevich ◽  
L. S. Molchanov ◽  
E. N. Sigarev ◽  
S. A. Dudchenko ◽  
V. V. Vakul'chuk ◽  
...  
Keyword(s):  
Reaction Zone ◽  
Initial Period ◽  
Video Recording ◽  
Slag Formation ◽  
Double Row ◽  
Metal Melt ◽  
Converter Bath ◽  
Foamed Slag ◽  
Aggressive Action ◽  
Laval Nozzles

Further increase of resources- and energy-saving efficiency of BOF processes is unthinkable without development of new methods of blowing and designs of blowing devices. It requires information on the real physicochemical phenomena in the converter cavity accompanying the blowing of the converter bath using new designs of oxygen lances in order to assess the possible risks in the mastering of the proposed developments in industrial conditions. The paper presents the results of video filming of the top blowing of a 80-kg converter bath by groups of multi-pulse supersonic and sonic oxygen jets formed, respectively, by Laval and cylindrical two-level nozzles of two designs equipped with double-row tips with a circular arrangement of Laval nozzles and cylindrical ones and upper block with cylindrical nozzles. Previously unknown information was obtained on the picture of the bath blowing with the formation of a reaction zone of interaction of supersonic and sonic oxygen jets with a metal melt with a flow of carbon monoxide going out the bath and afterburning of CO to CO2 under conditions of a counter-directed double curtain of sonic oxygen jets at different levels of location of the foamed slag-metal emulsions. It was established that in the initial period of blowing during slag formation most of the thermal energy of CO to CO2 combustion flares is transferred to the surface of the bath with lumps of added lime, and the rest is transferred by forced convection to the converter walls and gases escaping from the bath to the neck. In the case of the location of the foamed slag level at the upper tier of the cylindrical nozzles of the lance, heat transfer from high-temperature flares of localized afterburning of CO to CO2 within a limited in size near-lance flow of exhaust gases from the reaction zone is carried out according to the laws of submerged combustion and is completed completely in foamed slag-metal emulsion with the prevention of aggressive action of afterburning flares and volumes of overheated slag on the converter lining. Revealed and recorded by video recording modes of blowing the converter bath, contributing to the development of such undesirable phenomena during smelting as the appearance of intense emissions of slag-metal suspension from the facility, coagulation of the slag with the cessation of dephosphorization of the metal melt, the development of intense dust formation and the removal of small metal particles and slag with the formation of crust on the lance barrel. A variant of the final stage of blowing with a transition to supplying nitrogen instead of oxygen through cylindrical nozzles of two-level lances was experimentally tested, which provides an effective reduction in the level of foamed slag-metal emulsion before the converter turning down. The data obtained were used in the development of an industrial design of a two-level lance with a double-row tip, blowing and slag modes of blowing a converter bath with its use.

Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 1. Facility and methodology of the study

2021 ◽  
Vol 77 (8) ◽  
pp. 969-976
Author(s):  
A. G. Chernyatevich ◽  
L. C. Molchanov ◽  
E. N. Sigarev ◽  
S. A. Dudchenko ◽  
V. V. Vakal’chuk ◽  
...  
Keyword(s):  
High Temperature ◽  
Reaction Zone ◽  
Video Camera ◽  
Bath Surface ◽  
Hot Metal ◽  
Metal Melt ◽  
Physicochemical Processes ◽  
Video Registration ◽  
Foamed Slag ◽  
Practical Information

Interaction of the upper oxygen jets with the BOF bath considerably effects the hot metal refining flow. To optimize the lances designs and methods of BOF bath blowing, information is needed on the actual physical and technical phenomena taking place during top blowing of BOF bath by groups of ultrasonic and sonic oxygen jets. It was shown that obtaining the information is possible at high temperature simulation of the BOF bath blowing by application oxygen lances of various designs and video registration. Results of previous studies by filming of the blowing in a BOF and OHF presented. Description of modern facilities of high temperature simulation within a multi-purpose 160 and 60‒80 kg BOFs, equipped by special manholes for observation and registration by video camera the physicochemical processes taking place on the surface of the bath presented. In particular the manholes made it possible to observe the processes taking place at various methods of top and combined blowing of the BOF bath by application regular, two-circuit and double-flow oxygen lances. A methodology of test heats carrying out presented, which ensured obtaining important practical information on forming and variation of dimensions of the reaction zone. In particular, information was obtained about the interaction of ultrasonic and sonic oxygen jets with the metal melt, development of afterburning, emission out of reaction zone C to CO2 in the subsonic and sonic oxygen jets with forming high temperature flares directed on the BOF bath surface or penetrated in the foamed slag, emissions of slag-metal suspension out the BOF, forming of metal-slag sculls on the lance tube during the blowing with various level of foamed slag-metal emulsion.

scholarly journals Physical and chemical processes in the cavity of the oxygen converter when burning the bath with the afterburning of exhaust gases

2019 ◽  
pp. 116-128
Author(s):  
A.G. Chernyatevich ◽  
L.S. Molchanov ◽  
V.V. Vakulchuk ◽  
B.Y. Yushkevich
Keyword(s):  
High Temperature ◽  
Carbon Content ◽  
Oxygen Converter ◽  
Slag Formation ◽  
High Carbon ◽  
High Carbon Content ◽  
Double Row ◽  
Exhaust Gases ◽  
Converter Bath ◽  
Temperature Modeling

The aim of the study is to study the characteristics of physicochemical processes in the cavity of an oxygen converter when purging a bath through two-tier tuyeres of various designs. The analysis showed that the classical designs of oxygen tuyeres equipped with tips with Laval nozzles do not always satisfy the requirements of the technology. The article presents the results of laboratory high-temperature modeling of the process of purging the converter bath through two-tier tuyeres equipped with tips of various designs. The studies were carried out on a multipurpose installation mounted on the basis of a 150-kg induction furnace and a 60-kg converter manufactured at a scale of 1:18 relative to 160 tons of an industrial unit. It is shown that the use of a two-tier lance provides additional advantages for the smelting process. So, in the initial and main periods of purging the converter bath through a two-tier lance with a double-row tip, it was possible to accelerate the process of slag formation without the addition of fluorspar, to intensify the removal of phosphorus at a high carbon content. Upon completion of the initial purge period at a low metal temperature of 1300-1330 ° C and the corresponding basicity of liquid slag, the degree of dephosphorization of 73.3-79.1% is achieved. When used for blowing two-tier tuyeres with double-row tips, the efficiency of afterburning of CO exhaust gases to CO2 also increases at the same decarburization rate of the bath. Based on the data of high-temperature modeling, the rational design of the two-tier lance has been determined, which ensures: balance of the heat balance; yield increase; creating conditions for the removal of phosphorus at a high carbon content; exclusion of negative effects on the lining.

Video registration of physicochemical processes in BOF cavity at bath top blowing at application oxygen lances of various designs. Report 2. The picture of bath blowing at application two-circuit lances

2021 ◽  
Vol 77 (9) ◽  
pp. 1011-1019
Author(s):  
A. G. Chernyatevich ◽  
L. C. Molchanov ◽  
E. N. Sigarev ◽  
S. A. Dudchenko ◽  
V. V. Vakal’chuk ◽  
...  
Keyword(s):  
Reaction Zone ◽  
Coming Out ◽  
Final Stage ◽  
Bath Surface ◽  
Slag Formation ◽  
Basic Part ◽  
Physicochemical Processes ◽  
Video Registration ◽  
Foamed Slag ◽  
Reaction Zones

To elaborate blowing and slag modes, a clear picture of BOF bath blowing in various periods of heat is needed. It can be obtained by video registration of physicochemical processes in a BOF cavity. Results of video filming of BOF bath blowing with application two-circuit oxygen lances of five designs presented. Reliable information was obtained on rational form of organization of reaction zone of interaction of ultrasonic and sonic oxygen jets with BOF bath. The picture of physicochemical processes within the reaction zone of interaction of oxygen jets with metal, slag and gas phases of the cavity, preceded to a stable “ignition” of a heat and in the process of the whole heat. A possibility was revealed to accelerate the processes of lime dissolving and slag formation and phosphor removal intensification. The intensification can be accomplished by increase of the number of reaction zones of interaction of ultrasonic and sonic oxygen jets on bath surface and forming of foamed slag-metal emulsion, being stable within the basic part of blowing time. It was shown that at initial period of a heat, it is necessary to ensure consolidation of supersonic oxygen jets, coming out of different reaction zones of interaction. It will enable to oncoming jets to create a curtain on the way of metal and slag drops taking away, to form a flare of CO afterburning to CO2 and ensure heat energy transfer from them to mainly the bath surface. It was established that at the location of the foamed slag-metal emulsion level higher the head end of the lance, the high-temperature products of CO to CO2 afterburning reaction transfer the heat of CO surrounding macro bubble to the shell of slag-metal emulsion. An additional control effect of “hard” supersonic oxygen jets on the bath was also established when replacing the subsonic and sonic oxygen jets by nitrogen ones. At that the flow rate of nitrogen should be big enough to prevent the sealing of cylinder nozzles of the lance head by metal and slag drops during final stage of blowing. The variant of the final stage of blowing was checked experimentally by transfer to the “hard” supersonic oxygen blow, contributing to final metal and slag oxidation decrease.

scholarly journals DIRECT OBSERVATION OF HIGH-TEMPERATURE AREAS OF METAL MELT AT OXYGEN CONVERTER BLOWING WITH LOW VOLTAGE APPLICATION

2021 ◽  
Vol 17 (4) ◽  
pp. 44-54
Author(s):  
Sergiy Semykin ◽  
Tetiana Golub ◽  
Sergiy Dudchenko
Keyword(s):  
High Temperature ◽  
Reaction Zone ◽  
Potential Application ◽  
Low Voltage ◽  
Video Recording ◽  
Negative Polarity ◽  
Visual Observation ◽  
Reaction Zones ◽  
Voltage Potential ◽  
Bottom Blowing

Introduction. The process of oxygen conversion, despite the existing improvements, can be supplemented by physical methods of influence, including the unconventional method of applying low-voltage potential developed at the Iron and Steel Institute of the NAS of Ukraine.Problem Statement. The studies of the method of low-voltage potential application on 60, 160 and 250 ton converters have shown that the technology intensifies thermophysical and hydrodynamic processes in the gasslag-metal system and increases the converter process efficiency.Purpose. The purpose of this research is to study the features of the influence on the reaction zones of the low voltage potential application at four blowing options with the use of high-temperature physical model.Materials and Methods. A physical model that simulates the top, bottom and combined oxygen blowing under low-voltage potential application of different polarity on the lance has been used. An insert of a transparent quartz plate is made in one of the walls for visual observation and video recording. The top blowing is conductedwith two nozzle lance (nozzle diameter 1.7 mm with an angle of 30 ° to the lance). The bottom blowing is conducted with a bottom tuyere with a 1.5 mm diameter central nozzle. Combined blowing is realized by a combination ofthese options.Results. The visual observation of the reaction zones with different blowing options has shown that the highest temperature and the largest dimensions of the brightest parts of the bath correspond to the combined blowing, while the lowest ones are reported for the bottom blowing. While applying the low-voltage potential method it has been established that the reaction zone is longer at the positive polarity on the lance, during the period of silicon oxidation, and at the negative polarity on the lance, during the period of intense carbon oxidation. The video of gas bubbles flotation, probably CO, has shown that the bubbles are formed more intensively in thecase of negative polarity on the lance.Conclusions. The applied technique has allowed estimating the influence of low-voltage potential application on the geometric parameters of the reaction zone.

scholarly journals Study of efficiency of liquid steel homogenization with blowing through blocks of various designs

2018 ◽  
pp. 76-80
Author(s):  
L Molchanov ◽  
N Sheremeta ◽  
Y Synehin
Keyword(s):  
Rational Design ◽  
Gas Flow ◽  
Video Recording ◽  
Similarity Criteria ◽  
Practical Significance ◽  
Design Parameters ◽  
Production Cycle ◽  
Metal Bath ◽  
Metal Melt ◽  
Process Gases

At modern metallurgical plants, blowing of steel with process gases is an obligatory component of the production cycle. In this case, it is most difficult to organize the supply of stirring gas through the bottom of a metallurgical unit. In the practice of metallurgical production, blowing units of various designs (slotted, channel and with non-directional porosity) are used to inject process gases under such a scheme. Considering that the influence of the design of the bubbler of the bottom blowing unit on the efficiency of mass transfer in a metal bath has not been studied, the aim of this study was to determine the influence of the design of the blowing unit on the efficiency of homogenization of the metal melt. To achieve this goal, the method of physical water modelling was used, based on a modified π-theorem. In order to obtain adequate results, similarity numbers (homochromicity number, dimensionless volume flow number, linear simplex and density simplex) were defined to describe the process of fluid homogenization, and an experimental installation was built that allows video recording of experiments with high image quality. According to the simulation results, photographs were obtained illustrating the dynamics of changes in the level of liquid homogenization over time (assessed by the indicator redistribution rate in the bath volume) for blowing units of various designs and different gas flow rates. The scientific novelty of the conducted research is the determination of similarity criteria describing the process of homogenization of a metal melt when blowing with an inert gas. The practical significance lies in the proposed innovative design of the blowing unit, for which rational design parameters and necessary and sufficient for rapid homogenization parameters of the blowing were defined.

scholarly journals Nature of dust and smoke generation during gas-oxygen blasting in converter bath

2021 ◽  
Vol 64 (2) ◽  
pp. 112-121
Author(s):  
V. V. Solonenko ◽  
E. V. Protopopov ◽  
M. V. Temlyantsev ◽  
N. F. Yakushevich ◽  
S. O. Safonov
Keyword(s):  
Reaction Zone ◽  
Dust Emission ◽  
Combustion Products ◽  
Metal Films ◽  
Oxygen Flow ◽  
Metal Loss ◽  
Bath Surface ◽  
Converter Bath ◽  
Metal Impurities ◽  
Smoke Generation

The article presents the study of the nature of dust and smoke generation during gas-oxygen blasting of a converter bath. The main reasons causing metal waste have been determined. Influence of the process main parameters on metal loss has been studied during dust removal and evaporation of iron in the reaction zone. The authors have estimated the process of metal pulverization due to CO bubbles floating, determined by the rate of their rise to the bath surface. Specifics of temperature regime of the reaction zone and heat balance have been determined when adding fuel to the oxygen flow. Adding fuel to oxygen makes it possible to increase heat input into the bath, while reducing the rate of decarburization. This enables reduction of dust discharge during rupture and crush of metal films by gas bubbles. The effect of combustion products oxygen use on metal impurities oxidation is considered. By the example of blasting carbon and alloyed steel for mill rolls, it has been shown that the degrees of CO2 and H2O decomposition in the bath are the main qualities of gas-oxygen blasting. These indicators determine the oxidizing and heating properties of the blast. Assessment of change in total, consumed heat and its losses with exhaust gases, depending on degree of the oxygen flow dilution with natural gas (methane), has been carried out. Under these conditions, use of submersible combustion torches with change in their oxidizing ability makes it possible to solve various technological tasks, including provision of an effective way to reduce dust emission in converter process.

scholarly journals The researches of high-temperature properties of iron materials in laboratory conditions

2018 ◽  
pp. 64-79
Author(s):  
A.S. Nesterov ◽  
L.I. Garmash ◽  
K.P. Lopatenko ◽  
M.G. Boldenko ◽  
N.V. Gorbatenko ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Iron Ore ◽  
Raw Materials ◽  
Initial Period ◽  
Slag Formation ◽  
Integrated Method ◽  
Laboratory Conditions ◽  
Liquid Phases ◽  
Coke Layer ◽  
Slag Melt

The aim of the study is to simulate in laboratory conditions the behavior of iron ore materials in the zone of softening-melting DP and drip flow using an integrated method developed at the Institute of Ferrous Metallurgy. It is shown that the widespread idea of the formation in the blast furnace of primary slag melt based on FeO takes place mainly in the initial period of slag formation and is true for low basicity iron ore materials. For pellets, the nature of the formation of liquid phases differs significantly from the agglomerate. Experimentally established changes in the composition of the slag melt as heating. It is shown that under the conditions of temperature and heat treatment of raw materials, each temperature has its own composition of the liquid phase. When the pellets are melted, the primary melt is formed in the temperature range of 1330–13600C, in which the proportion of primary slag is 16–25%. Melt from high-silicon lumpy ore is formed at high temperatures of 1490-15200С. The mass of the primary slag with 42-48% FeO is 4-8% by weight of iron ore materials. The main part of the melt hangs on the coke nozzle on the coke layer at temperatures above 16000C. Melts formed from mixtures of iron-containing materials, as a rule, have averaged characteristics. The observed patterns make it possible to predict the behavior and properties of multicomponent charge mixtures in a blast furnace.

TEM characterization of reaction zone in a SiC fiber-reinforced titanium alloy

1988 ◽  
Vol 46 ◽  
pp. 738-739
Author(s):  
G. Das ◽  
R. E. Omlor
Keyword(s):  
Titanium Alloys ◽  
Reaction Zone ◽  
Carbon Layer ◽  
Fiber Reinforced ◽  
Reaction Products ◽  
Sic Fibers ◽  
Sic Fiber ◽  
The Matrix ◽  
Immense Potential

Fiber reinforced titanium alloys hold immense potential for applications in the aerospace industry. However, chemical reaction between the fibers and the titanium alloys at fabrication temperatures leads to the formation of brittle reaction products which limits their development. In the present study, coated SiC fibers have been used to evaluate the effects of surface coating on the reaction zone in the SiC/IMI829 system.IMI829 (Ti-5.5A1-3.5Sn-3.0Zr-0.3Mo-1Nb-0.3Si), a near alpha alloy, in the form of PREP powder (-35 mesh), was used a茸 the matrix. CVD grown AVCO SCS-6 SiC fibers were used as discontinuous reinforcements. These fibers of 142μm diameter contained an overlayer with high Si/C ratio on top of an amorphous carbon layer, the thickness of the coating being ∽ 1μm. SCS-6 fibers, broken into ∽ 2mm lengths, were mixed with IMI829 powder (representing < 0.1vol%) and the mixture was consolidated by HIP'ing at 871°C/0. 28GPa/4h.

Enhancing Clinical Supervision Using High-Definition Real-Time Digital Recording, Annotation, and Bluetooth Technology

2019 ◽  
Vol 4 (2) ◽  
pp. 356-362
Author(s):  
Jennifer W. Means ◽  
Casey McCaffrey
Keyword(s):  
Graduate Students ◽  
Data Collection ◽  
Real Time ◽  
Clinical Supervision ◽  
Video Recording ◽  
Advanced Technology ◽  
High Definition ◽  
Recording Technology ◽  
Self Confidence ◽  
Additional Data Collection

Purpose The use of real-time recording technology for clinical instruction allows student clinicians to more easily collect data, self-reflect, and move toward independence as supervisors continue to provide continuation of supportive methods. This article discusses how the use of high-definition real-time recording, Bluetooth technology, and embedded annotation may enhance the supervisory process. It also reports results of graduate students' perception of the benefits and satisfaction with the types of technology used. Method Survey data were collected from graduate students about their use and perceived benefits of advanced technology to support supervision during their 1st clinical experience. Results Survey results indicate that students found the use of their video recordings useful for self-evaluation, data collection, and therapy preparation. The students also perceived an increase in self-confidence through the use of the Bluetooth headsets as their supervisors could provide guidance and encouragement without interrupting the flow of their therapy sessions by entering the room to redirect them. Conclusions The use of video recording technology can provide opportunities for students to review: videos of prospective clients they will be treating, their treatment videos for self-assessment purposes, and for additional data collection. Bluetooth technology provides immediate communication between the clinical educator and the student. Students reported that the result of that communication can improve their self-confidence, perceived performance, and subsequent shift toward independence.

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