Specific Features of Blowing a Converter Bath with the Application of Modernized Two-Story Oxygen Lances

The aim of the work is to carry out an economic assessment of the effect of various structures of multi-tiered oxygen lances and methods for flushing the converter bath with the afterburning of waste gases on the efficiency of the production of iron-carbon semi-products in a modern metallurgical plant. The study was conducted for the process of steel smelting in converters of combined blowing with supply of oxygen from above and neutral gas through the bottom in the conditions of using conventional and multi-tiered oxygen tuyeres. Studies on the afterburning of converter gas in the converter cavity showed that, in proportion to the increase in the proportion of CO2 in the exhaust gases, the costs of steel production are reduced. Compared with the use of tuyeres of classical construction, they amount to 3.23 US dollars / ton of steel for double-circuit, 6.81 US dollars / ton of steel for bunk, and 11.61 US dollars / ton of steel for three-tier. It was determined that when using the classic design of the upper oxygen tuyere, the lower heat of combustion of the converter gas is 10 MJ / m3. In comparison with the classical design, the two-tier, double-circuit and three-tier tuyeres ensure a reduction in the lower heat of combustion of the converter gas by 8,5; 4.4 and 27.1% (rel.), Respectively. On the basis of the data obtained, it is possible to draw a conclusion about the effectiveness of using the technology of combined blowing of the converter bath with the afterburning of exhaust gases in the converter cavity.

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FORMATION PECULARITIES OF METALL-SLAG SKULLS ON TWO-LEVEL OXYGEN LANCES AT BLOWING OF CONVERTER BATH

Izvestiya Ferrous Metallurgy ◽

10.17073/0368-0797-2015-4-248-257 ◽

2015 ◽

Vol 58 (4) ◽

pp. 248 ◽

Cited By ~ 1

Author(s):

E. V. Protopopov ◽

A. G. Chernyatevich ◽

S. V. Feiler ◽

V. V. Vakul’chuk ◽

A. N. Sokol

Keyword(s):

Converter Bath

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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

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2021-11-1142-1155 ◽

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.

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