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.

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.

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.

scholarly journals Effect of the Fe2O3 Addition Amount on Dephosphorization of Hot Metal with Low Basicity Slag by High-Temperature Laboratorial Experiments

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 417
Author(s):  
Wenkui Yang ◽  
Jian Yang ◽  
Yanqiu Shi ◽  
Zhijun Yang ◽  
Fubin Gao ◽  
...  
Keyword(s):  
Solid Solution ◽  
High Temperature ◽  
Theoretical Calculation ◽  
Oxygen Potential ◽  
Oxygen Activity ◽  
Hot Metal ◽  
Rich Phase ◽  
Addition Amount

In this paper, the influence of the Fe2O3 addition amount on the dephosphorization of hot metal at 1623 K with the slag of the low basicity (CaO/SiO2) of about 1.5 was investigated by using high-temperature laboratorial experiments. With increasing the Fe2O3 addition amount from 5 to 30 g, the contents of [C], [Si], [Mn] and [P] in the hot metal at the end of dephosphorization are decreased and the corresponding removal ratios increase. In dephosphorization slags, the phosphorus mainly exists in the form of the nCa2SiO4–Ca3(PO4)2 solid solution in the phosphorus-rich phase and the value of coefficient n decreases from 20 to 1. Furthermore, the oxygen potential and activity at the interface between the slag and hot metal are increased. When the oxygen potential and the oxygen activity at the interface are greater than 0.72 × 10−12 and 7.1 × 10−3, respectively, the dephosphorization ratio begins to increase rapidly. When the Fe2O3 addition amount is increased to 30 g, the ratio of the Fe2O3 addition amount to theoretical calculation consumption is around 175%, and the dephosphorization ratio reaches the highest value of 83.3%.

EAF Gas Waste Heat Utilization and Discussion of the Energy Conservation and CO2 Emissions Reduction

2016 ◽  
Vol 35 (2) ◽  
pp. 195-200 ◽  
Author(s):  
Ling-zhi Yang ◽  
Rong Zhu ◽  
Guo-hong Ma
Keyword(s):  
High Temperature ◽  
Energy Saving ◽  
Waste Heat ◽  
Hot Metal ◽  
Coal Gas ◽  
Heat Utilization ◽  
High Temperature Furnace ◽  
Metal Ratio ◽  
Waste Heat Utilization ◽  
Temperature Furnace

AbstractAs a large number of energy was taken away by the high temperature furnace gas during the EAF smelting process, a huge economic and environmental benefits would obtained to recycle and utilize. In this paper, the energy of the EAF was analyzed theoretically with the hot metal ratio of 50%. Combined with the utilization of the gas waste heat during the scrap preheating, electricity generation, production of steam and production of coal gas processes, the effect of the energy saving and emission was calculated with comprehensive utilization of the high temperature furnace gas. An optimal scheme for utilization of the waste heat was proposed based on the calculation. The results show that the best way for energy saving and carbon reduction is the production of coal gas, while the optimal scheme for waste heat utilization is combined the production of coal gas with the scrap preheating, which will save 170 kWh/t of energy and decrease 57.88 kg/t of carbon emission. As hot metal ratio in EAF steelmaking is often more than 50%, which will produce more EAF gas waste heat, optimizing EAF gas waste heat utilization will have more obvious effect on energy saving and emission reduction.

scholarly journals A Si-Cl geothermobarometer for the reaction zone of high-temperature, basaltic-hosted mid-ocean ridge hydrothermal systems

2009 ◽  
Vol 10 (5) ◽  
pp. n/a-n/a ◽  
Author(s):  
Fabrice J. Fontaine ◽  
William S. D. Wilcock ◽  
Dionysis E. Foustoukos ◽  
David A. Butterfield
Keyword(s):  
High Temperature ◽  
Reaction Zone ◽  
Hydrothermal Systems ◽  
Mid Ocean Ridge ◽  
Ocean Ridge

Spectroscopic Observation of Chemical Species From High-Temperature Air Pulverized Coal Combustion

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
Nelfa Desmira ◽  
Takuya Nagasaka ◽  
Kimihito Narukawa ◽  
Akira Ishikawa ◽  
Kuniyuki Kitagawa ◽  
...  
Keyword(s):  
High Temperature ◽  
High Temperatures ◽  
Flame Temperature ◽  
Chemical Species ◽  
Emission Spectra ◽  
Video Camera ◽  
Spectroscopic Observation ◽  
Pulverized Coal ◽  
In Situ Monitoring ◽  
Lean Combustion

In situ monitoring of chemical species from the combustion pulverized coal in high-temperature air is examined using several different spectroscopic diagnostic at different equivalence ratios. Two-dimensional (2D) distributions of flame temperature were obtained using a thermal video camera. The experimental results showed the temperatures to range from low to 1400 °C under various conditions of fuel-lean, stoichiometric, and fuel-rich. The highest temperature and flame stability were obtained under fuel-lean combustion condition. The chemical species generated from within the combustion zone were analyzed from the spontaneous emission spectra of the flame in the Ultraviolet–visible (UV-Vis) range. The spatial distribution of NO, OH, and CN were identified from the spectra. The 2D distribution of emission intensity visualized and recorded for NO, OH, and CN revealed high-temperatures close to the root of the flame that rapidly dispersed radially outward to provide very high temperatures over a much larger volume at further downstream locations of the flame.

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.

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