CN1227265A - Method for injection of oxygen in electric arc furnace in the production of steel - Google Patents
Method for injection of oxygen in electric arc furnace in the production of steel Download PDFInfo
- Publication number
- CN1227265A CN1227265A CN98126529A CN98126529A CN1227265A CN 1227265 A CN1227265 A CN 1227265A CN 98126529 A CN98126529 A CN 98126529A CN 98126529 A CN98126529 A CN 98126529A CN 1227265 A CN1227265 A CN 1227265A
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- CN
- China
- Prior art keywords
- oxygen
- furnace
- nozzle
- blown
- nozzles
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Links
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 239000001301 oxygen Substances 0.000 title claims abstract description 40
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 28
- 238000010891 electric arc Methods 0.000 title claims description 11
- 229910000831 Steel Inorganic materials 0.000 title abstract description 7
- 239000010959 steel Substances 0.000 title abstract description 7
- 238000002347 injection Methods 0.000 title abstract description 5
- 239000007924 injection Substances 0.000 title abstract description 5
- 238000004519 manufacturing process Methods 0.000 title abstract description 5
- 239000002184 metal Substances 0.000 claims abstract description 31
- 229910052751 metal Inorganic materials 0.000 claims abstract description 31
- 239000002893 slag Substances 0.000 claims abstract description 25
- 238000002485 combustion reaction Methods 0.000 claims description 17
- 238000005261 decarburization Methods 0.000 claims description 13
- 238000007664 blowing Methods 0.000 claims description 8
- 238000005520 cutting process Methods 0.000 claims description 8
- 238000009845 electric arc furnace steelmaking Methods 0.000 claims description 8
- 238000010438 heat treatment Methods 0.000 claims description 5
- 238000000576 coating method Methods 0.000 claims description 3
- 238000009628 steelmaking Methods 0.000 claims description 3
- 239000011248 coating agent Substances 0.000 claims description 2
- 230000015572 biosynthetic process Effects 0.000 abstract description 3
- 239000000126 substance Substances 0.000 description 15
- 238000006243 chemical reaction Methods 0.000 description 13
- 239000007787 solid Substances 0.000 description 11
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- 238000013019 agitation Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000003723 Smelting Methods 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 229910002804 graphite Inorganic materials 0.000 description 2
- 239000010439 graphite Substances 0.000 description 2
- 239000000155 melt Substances 0.000 description 2
- 229910001092 metal group alloy Inorganic materials 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000000996 additive effect Effects 0.000 description 1
- 238000005262 decarbonization Methods 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 239000002803 fossil fuel Substances 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000010309 melting process Methods 0.000 description 1
- 239000007769 metal material Substances 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 239000008188 pellet Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- 238000011084 recovery Methods 0.000 description 1
- 239000011819 refractory material Substances 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
Images
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Landscapes
- Refinement Of Pig-Iron, Manufacture Of Cast Iron, And Steel Manufacture Other Than In Revolving Furnaces (AREA)
- Vertical, Hearth, Or Arc Furnaces (AREA)
Abstract
A method for oxygen injection in electrical arc ovens for steel production where two oxygen guns at the end of each injection nozzle, placed on the electrical arc oven so that they work just on the melted metal in the area of foamy slag formation. It is intended that oxygen is blown from the injection nozzles covered with slag, at certain moments of the of the operation. The speed of gun on the lower hole is sonic and the speed of the gun on the lower hole is subsonic.
Description
The invention relates to an oxygen blowing method for electric arc furnace steelmaking, in particular to an oxygen blowing method for electric arc furnace steelmaking in the processes of cutting, decarbonizing and post-combustion of CO generated during decarbonization of metal melt.
During the melting of a metal charge in an Electric Arc Furnace (EAF) for the production of steel, the reaction between carbon present in the charge and oxygen blown into the furnace for the purpose of decarburization and cutting of the solid charge is referred to as decarburization: CO is generated by the reaction. Immediately after its generation, this CO reacts with oxygen blown into the furnace or present in the air coming in through the tap hole and the furnace door, as so-called post-combustion: reaction with resultant formation of CO2。
Both the decarburization reaction and the post combustion reaction are exothermic reactions. But result fromThe reaction of the CO in the furnace with the oxygen blown into the furnace or present in the air transfers little heat (chemical energy) to the solid charge, because this post-combustion reaction takes place in the upper part of the furnace, in the region comprised between the slag line and the exhaust pipe, and the energy contained in this gas is rapidly dissipated in the upper part of the furnace and consequently is removed via the exhaust system, rather than being transferred to the solid charge to the desired extent. In addition, part of the generated heat (chemical energy) is lost to heating the N present in the air entering through the tap hole and the oven door2. On the other hand, heat transfer (chemical energy) from the post-combustion reaction to the metal melt is also poor, since the post-combustion reaction takes place above the slag line, which in turn acts as an insulator, with the result that heat transfer (chemical reaction) to the metal melt becomes less valuable.
In view of the increasing competition in the metallurgical industry and the compliance with the requirements of environmental laws, these companies have focused their efforts on electric arc furnace steelmaking techniques, which attempt to reduce the demand for electrical energy, increase productivity, reduce environmental pollution, improve their utilization from the input of energy, and improve the rational utilization of the chemical energy of the CO generated in the furnace.
In order to take advantage of the chemical energy emitted by the CO reaction in the furnace, it has been proposed to use auxiliary quantities of O2I.e. a process known as post-combustion, which employs one or more oxygen nozzles in the region above the slag line during the melting of the solid charge. This method has been shown to be almost ineffective in transferring heat (chemical energy) to the solids because the nozzle is positioned too far above the slag line and, as the melting of the solids progresses, the height of the nozzle decreases, moving away from the hot zone to a point where the heat transfer (chemical energy) from the reaction to the solids is no longer satisfactory. Such solutions are also ineffective in terms of heat transfer (chemical energy) to the metal melt, since they are located too far above the slag line and cannot reach the metal melt because the slag itself acts as a thermal barrierBulk heat transfer (chemical energy).
It is therefore an object of the present invention to provide an oxygen lance for electric arc furnace steelmaking which transfers the chemical energy from the post-combustion reaction of CO to the charge and the metal melt in an efficient manner.
Another object of the present invention is to provide an oxygen blowing method for electric arc furnace steelmaking which can decarburize a molten metal uniformly and efficiently.
FIG. 1 is a cross-sectional view of an electric arc furnace depicting the location of a nozzle.
FIG. 2 is a plan view of an electric arc furnace depicting a method of installing the nozzle.
These and further objects of the invention are achieved by: during the cutting, decarburization and post-combustion of the CO formed during the decarburization of the metal melt, O is continuously injected by means of one or more nozzles 1 for hydrogen peroxide injection2Blown into a steelmaking arc furnace, said nozzle being mounted on the furnace wall, an upper jet 2 being a subsonic jet and a lower jet 3 being a supersonic jet, the nozzle being located in the slagging zone, or just above the slag line, and operating at a certain moment during the operation covered by slag 4. Furthermore, the subsonic 2 and supersonic 3 streams emerging from the nozzle through the holes at the ends thereof are dimensioned so as to counteract the splashing normally caused by the supersonic stream inside the electric arc furnace and to direct them towards a certain portion of the furnace so as to minimize the wear of the refractory coatings and electrodes during the steel production.
The supersonic lower jet 3 of oxygen is used for cutting and decarburizing a charge of solid metal ( ) And stirring the formed metal melt. The mechanical agitation of the foamed slag and the melt caused by the jet increases the interface between them and achieves an efficient heat transfer (chemical energy) process between the foamed slag and the metal melt. Since it is preferred to use the nozzle 1 at more than one point in the furnace, the supersonic jet 3 promotes a faster and more uniform decarburization of the metal melt, thereby accelerating the steelmaking process.
Subsonic upper oxygen jet 2 for afterburning: ( ) So that in the cutting step heat (chemical energy) is transferred from the reaction to the solid charge, and in the decarburization step CO is retained in the foamy slag, thereby heating the slag. The agitation produced in this region by the supersonic jet 3 transfers this heat to the metal melt, with the result that the melt temperature is rapidly increased.
The process of the present invention provides higher heat transfer (chemical energy) efficiency because the nozzles are positioned in the slagging zone, or just above the slag line, so that these reactions take place in the lower region of the furnace, with the result that the heat exchange time with the metal melt forming the planes when the solid charge is present in the furnace is increased by the progress of the stirring of the slag and melt by the supersonic and subsonic jets.
The process of the invention also allows the specific consumption of electrical energy per ton of steel to be reduced, since the benefits of chemical energy from the post-combustion of CO are taken in a more efficient manner, increasing the consequences of heat supply, in such a way as to transfer this heat to the metal charge up to 90%. This is because: the reaction takes place in the foamy slag formation zone so that the hot gases have a longer residence time in the fully molten charge phase before they exit through the conduit of the furnace and thus impart more of this energy to the solid charge, thereby causing the reaction to take place within the foamy slag by promoting the heating of the fully molten metal phase and the agitation caused in the foamy slag and melt by the supersonic jet.
The invention increases the productivity due to increasing the heat supply, thereby increasing the production by the existing equipment; the dust temperature and the smoke volume generated by ton of steel are reduced due to more CO combustion in the furnace, so that the atmospheric pollution degree in an operation area is reduced; and due to the improved uniform temperature, it is possible to shorten the time for treating the steel and lower the wear of the refractory material.
In addition to the above advantages, the method of the present invention eliminates the use of conventional oxygen blowing equipment and devices, such as cooled retractable supersonic nozzles, handling racks and robotic arms for manipulating consumable blow tubes, which have heretofore been used in electric arc furnace oxygen blowing devices, and eliminates the need to blow oxygen through the furnace door, thereby avoiding the inconvenience of such operations as described above.
According to the electric arc furnace steelmaking process, a metal charge consisting of any desired mixture of scrap, cast iron, direct reduced iron pellets, various metal alloys, fluxes and carbon (in various possible shapes, in lump or powder form) is placed in a smelting furnace. In addition to electrical energy, oxygen and fossil fuels can also be used as energy sources for smelting.
The electric arc furnace is composed of a metal furnace shell 6 lined with a refractory coating, a furnace cover 7 and a conduit 9, wherein metal furnace burden is placed in the furnace shell 6, the furnace cover covers the upper part of the furnace shell, the furnace cover 7 is provided with a hole 8, a graphite electrode, a metal alloy and an additive of pre-reduced iron are added through the hole, and hot gas and dust from the furnace are removed from a furnace caliber pipe 9. Melting of the metal charge takes place by means of the energy emitted by the electric arc formed between the end of the graphite electrode 5 and the metal charge.
Before the furnace is filled with metal, the furnace cover 7 supporting the electrodes is opened and then swung sideways. The charging basket containing the metal material is moved to the upper part of the furnace, and then the furnace burden is discharged into the furnace through an opening at the lower part of the charging basket. After the charging operation, the furnace lid is moved back, lowered and covered, and the melting process is startedby lowering the electrodes until they form an electric arc with the metal charge, thus delivering the electric energy required for melting the metal charge. Another energy source for melting the charge is chemical energy from the oxidation of the elements contained in the charge.
According to the invention, after heating the metal charge by the heat generated by the electric arc for a few minutes, oxygen is blown with the two-oxygen flow nozzle 1 to cut the metal charge and start decarburization, and post-combustion of CO is carried out. The nozzle specifically designed for the process of the invention has two separate internal tubes which blow oxygen for cutting and decarburization (supersonic jet) and oxygen for post-combustion of the CO produced during cutting and decarburization (subsonic jet), the tubes being provided with one end with small holes designed for the exit of the two oxygen streams.
Compared with other post-combustion systems of the prior art, the method of the invention has the following advantages: the specific energy yield of oxygen added for the post-combustion is 3.6kwh/m3-O2Within an order of magnitude of; due to the addition of monomers for post-combustionOxygen potentialThe productivity is improved; the equipment cost is reduced; the investment recovery is accelerated; the equipment, operation and maintenance are greatly simplified; little or no furnace changes are required.
The variant of the invention consists of the possibility of using nozzles with independent oxygen jets, one subsonic and the other supersonic, which are placed in the slagging zone, or just above the slag line, and which are operated at some point in the process covered with slag, the choice of nozzles with double oxygen jets or independent oxygen jets, one subsonic and the other supersonic having to be made taking into account the different sizes of the furnace and/or thedifferent types of charge.
Claims (9)
1. Oxygen blowing method for electric arc furnaces, characterized in that oxygen is blown through one or several double oxygen jet nozzles (1) mounted on the furnace wall, which nozzles (1) are in the slagging zone or just above the slag line and which nozzles are covered with slag (4) at a certain moment during the operating period, the two oxygen jets being blown through small holes located at the ends of the nozzles.
2. The method according to claim 1, characterized in that the lower jet of oxygen (3) is supersonic.
3. The method according to claim 1, characterized in that the upper oxygen jet (2) is subsonic.
4. The method of claim 1, wherein the oxygen jets 2 and 3 are directed in a manner to minimize refractory coating 5 and electrode wear during the steelmaking process.
5. The process according to claim 1, characterized in that, after heating the metal charge by the heat generated by the electrodes for several minutes, oxygen is blown to cut the metal charge, start the decarburization and carry out the post-combustion of CO.
6. The method according to claim 1, characterized in that oxygen is continuously blown into the furnace during the post-combustion of CO formed during the cutting, decarburization and decarburization of the metal melt.
7. Oxygen blowing method for electric arc furnace steelmaking, characterized in that oxygen is blown through a nozzle mounted on the furnace wall with separate oxygen jets, which nozzle is placed in the slagging zone or just above the slag line, which nozzle is covered with slag at certain moments of operation.
8. The method of claim 7, wherein one of the nozzles is a supersonic jet nozzle.
9. The process of claim 7, wherein one nozzle is a subsonic jet nozzle.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| BRPI9706510 | 1997-12-30 | ||
| BR9706510-2A BR9706510A (en) | 1997-12-30 | 1997-12-30 | Method for oxygen injection in electric arc furnaces for steel production. |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1227265A true CN1227265A (en) | 1999-09-01 |
| CN1095876C CN1095876C (en) | 2002-12-11 |
Family
ID=4068736
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN98126529A Expired - Fee Related CN1095876C (en) | 1997-12-30 | 1998-12-30 | Method for injection of oxygen in electric arc furnace in the production of steel |
Country Status (4)
| Country | Link |
|---|---|
| CN (1) | CN1095876C (en) |
| BR (1) | BR9706510A (en) |
| TR (1) | TR199802756A2 (en) |
| TW (1) | TW486520B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100478636C (en) * | 2001-07-10 | 2009-04-15 | 工艺技术国际股份有限公司 | Mounting arrangement for auxiliary burner or lance |
| CN101709351B (en) * | 2009-11-28 | 2011-06-01 | 山西太钢不锈钢股份有限公司 | Method for oxygen blast of electric furnace |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US8562713B2 (en) * | 2011-05-27 | 2013-10-22 | A. Finkl & Sons Co. | Flexible minimum energy utilization electric arc furnace system and processes for making steel products |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4034809A1 (en) * | 1990-11-02 | 1992-05-07 | Beda Oxygentech Armatur | Arc furnace lance robot used to manipulate e.g. carbon@ powder - has swing arms on rotating tower with motors to move the lances at required height and angle into the furnace |
| JP3148966B2 (en) * | 1994-05-12 | 2001-03-26 | 新日本製鐵株式会社 | Lance nozzle structure that blows oxygen gas into electric furnace |
| JP3239691B2 (en) * | 1994-10-27 | 2001-12-17 | 日本鋼管株式会社 | Arc furnace melting method |
| JPH08176639A (en) * | 1994-12-28 | 1996-07-09 | Nkk Corp | Arc furnace steelmaking |
| IT1280115B1 (en) * | 1995-01-17 | 1998-01-05 | Danieli Off Mecc | MELTING PROCEDURE FOR ELECTRIC ARC OVEN WITH ALTERNATIVE SOURCES OF ENERGY AND RELATED ELECTRIC ARC OVEN |
| US5635130A (en) * | 1995-06-07 | 1997-06-03 | Berry Metal Co. | Combined oxygen blowing/fuel burner lance assembly |
-
1997
- 1997-12-30 BR BR9706510-2A patent/BR9706510A/en not_active IP Right Cessation
-
1998
- 1998-12-30 CN CN98126529A patent/CN1095876C/en not_active Expired - Fee Related
- 1998-12-30 TW TW087121891A patent/TW486520B/en active
- 1998-12-30 TR TR1998/02756A patent/TR199802756A2/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN100478636C (en) * | 2001-07-10 | 2009-04-15 | 工艺技术国际股份有限公司 | Mounting arrangement for auxiliary burner or lance |
| CN101709351B (en) * | 2009-11-28 | 2011-06-01 | 山西太钢不锈钢股份有限公司 | Method for oxygen blast of electric furnace |
Also Published As
| Publication number | Publication date |
|---|---|
| BR9706510A (en) | 2000-03-14 |
| TR199802756A3 (en) | 1999-11-22 |
| TW486520B (en) | 2002-05-11 |
| TR199802756A2 (en) | 1999-11-22 |
| CN1095876C (en) | 2002-12-11 |
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