GB2095701A - Preheating of steel scrap - Google Patents
Preheating of steel scrap Download PDFInfo
- Publication number
- GB2095701A GB2095701A GB8109708A GB8109708A GB2095701A GB 2095701 A GB2095701 A GB 2095701A GB 8109708 A GB8109708 A GB 8109708A GB 8109708 A GB8109708 A GB 8109708A GB 2095701 A GB2095701 A GB 2095701A
- Authority
- GB
- United Kingdom
- Prior art keywords
- refining
- oxygen
- vessel
- steel
- scrap
- 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.)
- Withdrawn
Links
- 229910000831 Steel Inorganic materials 0.000 title claims abstract description 18
- 239000010959 steel Substances 0.000 title claims abstract description 18
- 238000007670 refining Methods 0.000 claims abstract description 37
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 29
- 239000001301 oxygen Substances 0.000 claims abstract description 29
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 29
- 239000002803 fossil fuel Substances 0.000 claims abstract description 10
- 239000000446 fuel Substances 0.000 claims description 16
- 238000000034 method Methods 0.000 claims description 11
- 239000003245 coal Substances 0.000 claims description 2
- 239000006185 dispersion Substances 0.000 claims description 2
- 239000010742 number 1 fuel oil Substances 0.000 claims description 2
- 239000003921 oil Substances 0.000 claims description 2
- 239000007787 solid Substances 0.000 claims description 2
- 239000000725 suspension Substances 0.000 claims description 2
- 238000010438 heat treatment Methods 0.000 description 5
- 238000007664 blowing Methods 0.000 description 3
- 238000002485 combustion reaction Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 239000000295 fuel oil Substances 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000007812 deficiency Effects 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 238000002844 melting Methods 0.000 description 1
- 230000008018 melting Effects 0.000 description 1
- 239000002245 particle Substances 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
Classifications
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/56—Manufacture of steel by other methods
- C21C5/562—Manufacture of steel by other methods starting from scrap
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
- C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
- C21C5/35—Blowing from above and through the bath
-
- 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
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Treatment Of Steel In Its Molten State (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Abstract
The preheating of a scrap steel charge prior to refining in a converter is carried out by injecting fossil fuel and oxygen at sub-stoichiometric ratios into the scrap charge through basal tuyeres of the vessel and simultaneously injecting the balance of oxygen required into the vessel from an overhead lance. <IMAGE>
Description
SPECIFICATION
Improvements in or relating to metal refining processes and apparatus
This invention relates to metal refining processes and apparatus and more particularly to processes and apparatus for the refining of steel.
It has already been proposed in the operation of a BOS or similar steel refining vessel to increase the scrap consumption of the vessel by providing a significant measure of scrap pre-heating in the vessel by the injection of fuel during a pre-heating phase prior to the blowing phase of refining.
Again, it has been proposed to inject the fuel by means of tuyeres disposed in or adjacent to the base wall of the refining vessel. However, a limitation to the quantity of fuel that can be introduced by this means, and therefore the preheating of scrap possible, is the requirement to provide oxygen for burning the introduced fuel at the appropriate stoichiometric quantities, which does involve a considerable volume of oxygen with most fuels.
It is an object of the present invention to overcome or at least substantially reduce this problem.
In accordance with the invention there is provided a method of refining steel comprising the steps of providing a charge of steel scrap for the refining vessel; injecting fossil fuel and oxygen through basal tuyeres of the vessel; and at the same time injecting oxygen into the refining vessel by means of an overhead lance.
According to another aspect of the present invention there is provided apparatus for refining steel comprising a steel refining vessel adapted to receive a charge of scrap; one or more sets of coaxial tuyeres located in or adjacent to the base wall of the refining vessel and arranged to supply in operation fossil fuel and oxygen to the refining vessel; and an overhead lance arranged to provide in operation oxygen to the refining vessel.
The fossil fuel and oxygen injected through the basal tuyeres will in practice be generally at substoichiometric ratios, the balance of the oxygen requirement being provided by the overhead lance.
We have found that with the method and apparatus of the invention it is possible to provide a most satisfactory pre-heating and melting of scrap in the refining vessel. Thus, whilst the oxygen supplied by the basal tuyeres is in itself insufficient to burn adequately the amount of fossil fuel capable of being injected through the basal tuyeres, it is possible to supply sufficient additional oxygen by the overhead lance to make up this deficiency.
We have found that in many instances, that satisfactory pre-heating will result with as much as ninety percent of the required oxygen for combination of the fuel being supplied from the overhead lance.
We believe that the success of the present invention is due at least partly to the matrix created by the scrap charge within the refining vessel diffusing the fuel/oxygen mixture so that a stable flame is produced within the scrap.
The fossil fuel used may comprise oil, coal-oil dispersions and suspensions or solid finely divided coal fuels.
Ignition of the fuel/oxygen mixture within the refining vessel is in commercial production achieved by incandescent particles retained in the hot refining vessel from the previous charge, thus the oxygen and fuel will ignite under substoichiometric conditions typical of those expected in production application.
We have found that heat recovery within the scrap matrix is most satisfactory with overall thermal efficiencies of the order of 50% being achievable. Again, we have found that the scrap is not oxidised significantly with pre-heat temperatures of the order of 6000C.
Again, we have found that pre-heat temperature as high as 1 ,3500C can be obtained without the production of melt. Under these conditions, an absolute increase in scrap consumption of about 20% over the previously regarded typical upper limit of about 25% of any given charge for a refining vessel.
As a minor but nonetheless most significant feature we have discovered that provided there is no melt of scrap basal tuyere wear is minimai.
The invention enables the satisfactory provision of efficient pre-heating to otherwise normal BOF refining systems having overhead lance blowing techniques by the installation of a few (typically two) co-axial tuyere sets, the outer of each tuyere set being utilised for the transfer of fuel whilst the inner annular passage of each tuyere set is utilised for the transfer of the limited oxygen injected by the basal tuyeres. We believe this arrangement
reduces the combustion intensity adjacent the
edge of the tuyere.
However, in some cases, the outer of each tuyere set may be used for the transfer of oxygen and the inner for the transfer of fuel.
We believe that the significant limitation of damage to tuyeres and surrounding refractories in practice is due to the admixture of the oxygen and fuel very largely above tuyere level within the bulge of the scrap, so that the portions of the vessel closely adjacent the tuyeres are not subjected to
inordinate combustion problems. Again, by the admixture of oxygen largely from the overhead lance and fuel from basal tuyeres, a more uniform pre-heat is obtained so that higher pre-heat levels can be achieved for equivalent scrap oxidisation
levels.
In order that the invention may be more readily
understood one embodiment thereof will now be
described by way of example with reference to the
accompanying drawing which is a diagrammatic
sectional side elevation of a steel refining vessel
according to the invention.
As will be seen the vessel 1 is provided with an
overhead lance 2 and a pair of co-axial tuyeres 3.
4 protruding through the basal wall 5 thereof. A
charge of scrap 6 is located within the vessel.
Fuel oil is injected through the annular opening of each of the sets of tuyeres 3, 4 whilst oxygen is injected through the overhead blowing lance 2 associated with the refining vessel.
In practice the overhead lance provides 90% and the tuyeres 10% of the required stoichiometric volume of oxygen for fuel combustion of the fuel oil injected.
It is found that the scrap can be heated to a temperature of 1 3500C, and at that point a molten metal charge comprising about 150% by mass of the scrap charge can be added to the refining vessel and normal refinery processing can thereafter proceed.
Claims (7)
1. A method of refining steel comprising the steps of providing a charge of steel scrap for a refining vessel; injecting fossil fuel and oxygen through basal tuyeres of the vessel; and at the same time injecting oxygen into the refining vessel by means of an overhead lance.
2. A method of refining steel according to Claim
1 wherein the fossil fuel and oxygen injected through the basal tuyeres are at substoichiometric ratios, the balance of oxygen requirement being provided by the overhead lance.
3. A method of refining steel according to Claim 2 wherein up to 90% of the oxygen requirement is provided by the overhead lance.
4. A method of refining steel wherein the fossil fuel comprises oil, coal-oil dispersions and suspensions or solid finely divided coal fuels.
5. A method of refining steel substantially as hereinbefore described with reference to the accompanying drawing.
6. Apparatus for refining steel comprising a steel refining vessel adapted to receive a charge of scrap; one or more sets of coaxial tuyeres located in or adjacent to the base wall of the refining vessel and arranged to supply in operation fossil fuel and oxygen to the refining vessel; and an overhead lance arranged to provide in operation oxygen to the refining vessel.
7. Apparatus for refining steel substantially as shown in and as hereinbefore described with reference to the accompanying drawing.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8109708A GB2095701A (en) | 1981-03-27 | 1981-03-27 | Preheating of steel scrap |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8109708A GB2095701A (en) | 1981-03-27 | 1981-03-27 | Preheating of steel scrap |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2095701A true GB2095701A (en) | 1982-10-06 |
Family
ID=10520711
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8109708A Withdrawn GB2095701A (en) | 1981-03-27 | 1981-03-27 | Preheating of steel scrap |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2095701A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0321443A3 (en) * | 1987-12-17 | 1990-01-17 | Voest-Alpine Stahl Donawitz Gesellschaft M.B.H. | Process and installation for continuously melting scrap |
| CN107916317A (en) * | 2017-10-24 | 2018-04-17 | 芜湖新兴铸管有限责任公司 | The heating unit and heating means of converter steel scrap |
| CN108411064A (en) * | 2018-04-11 | 2018-08-17 | 成都先进金属材料产业技术研究院有限公司 | The method of waste steel for electric furnace preheating |
-
1981
- 1981-03-27 GB GB8109708A patent/GB2095701A/en not_active Withdrawn
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0321443A3 (en) * | 1987-12-17 | 1990-01-17 | Voest-Alpine Stahl Donawitz Gesellschaft M.B.H. | Process and installation for continuously melting scrap |
| CN107916317A (en) * | 2017-10-24 | 2018-04-17 | 芜湖新兴铸管有限责任公司 | The heating unit and heating means of converter steel scrap |
| CN108411064A (en) * | 2018-04-11 | 2018-08-17 | 成都先进金属材料产业技术研究院有限公司 | The method of waste steel for electric furnace preheating |
| CN108411064B (en) * | 2018-04-11 | 2020-02-07 | 成都先进金属材料产业技术研究院有限公司 | Method for preheating electric furnace scrap steel |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |