US3847593A - Process for refining metals, in particular liquid pig iron, in oxygen converters with continuous control of the operative procedure - Google Patents
Process for refining metals, in particular liquid pig iron, in oxygen converters with continuous control of the operative procedure Download PDFInfo
- Publication number
- US3847593A US3847593A US00267694A US26769472A US3847593A US 3847593 A US3847593 A US 3847593A US 00267694 A US00267694 A US 00267694A US 26769472 A US26769472 A US 26769472A US 3847593 A US3847593 A US 3847593A
- Authority
- US
- United States
- Prior art keywords
- refining
- curve
- bath
- blowing
- oxygen
- 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.)
- Expired - Lifetime
Links
- 238000007670 refining Methods 0.000 title claims abstract description 41
- 238000000034 method Methods 0.000 title claims abstract description 40
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 239000001301 oxygen Substances 0.000 title claims abstract description 39
- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 39
- 230000008569 process Effects 0.000 title claims abstract description 26
- 229910000805 Pig iron Inorganic materials 0.000 title claims abstract description 19
- 239000007788 liquid Substances 0.000 title claims abstract description 18
- 229910052751 metal Inorganic materials 0.000 title abstract description 9
- 239000002184 metal Substances 0.000 title abstract description 9
- 150000002739 metals Chemical class 0.000 title abstract description 6
- 238000007664 blowing Methods 0.000 claims abstract description 31
- 230000006872 improvement Effects 0.000 claims description 2
- 239000007789 gas Substances 0.000 abstract description 31
- 239000002893 slag Substances 0.000 abstract description 17
- 229910000831 Steel Inorganic materials 0.000 abstract description 12
- 239000010959 steel Substances 0.000 abstract description 12
- 238000004364 calculation method Methods 0.000 abstract description 7
- 230000006870 function Effects 0.000 abstract description 5
- 229910001338 liquidmetal Inorganic materials 0.000 abstract description 5
- 230000001590 oxidative effect Effects 0.000 abstract description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 23
- 238000006243 chemical reaction Methods 0.000 description 14
- 229910052742 iron Inorganic materials 0.000 description 12
- 238000004458 analytical method Methods 0.000 description 11
- 238000002485 combustion reaction Methods 0.000 description 9
- 239000000203 mixture Substances 0.000 description 8
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- 229910002091 carbon monoxide Inorganic materials 0.000 description 6
- 235000008733 Citrus aurantifolia Nutrition 0.000 description 5
- 235000011941 Tilia x europaea Nutrition 0.000 description 5
- 238000012937 correction Methods 0.000 description 5
- 239000004571 lime Substances 0.000 description 5
- 239000011572 manganese Substances 0.000 description 5
- 238000005070 sampling Methods 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 4
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 229910052799 carbon Inorganic materials 0.000 description 4
- 229910002092 carbon dioxide Inorganic materials 0.000 description 4
- 238000005261 decarburization Methods 0.000 description 4
- 239000007787 solid Substances 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- WUKWITHWXAAZEY-UHFFFAOYSA-L calcium difluoride Chemical compound [F-].[F-].[Ca+2] WUKWITHWXAAZEY-UHFFFAOYSA-L 0.000 description 3
- 239000010436 fluorite Substances 0.000 description 3
- 239000003517 fume Substances 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 238000012544 monitoring process Methods 0.000 description 3
- 239000000428 dust Substances 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 229910001018 Cast iron Inorganic materials 0.000 description 1
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 1
- 241000282887 Suidae Species 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- -1 for molten pig iron Chemical class 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 238000013178 mathematical model Methods 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 230000004044 response Effects 0.000 description 1
- 239000010703 silicon Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 230000005477 standard model Effects 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 239000002918 waste heat Substances 0.000 description 1
Images
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
- C21C5/28—Manufacture of steel in the converter
- C21C5/30—Regulating or controlling the blowing
Definitions
- the present invention covers a process for refining metals, in particular liquid pig iron, in oxygen converters with continuous control of the operative procedure.
- the invention relates to a liquid pig iron refining process, where an instantaneous determination of the refining pattern is performed as well as a continuous bringing back to a pattern preestablished as a standard model to be attained for the type of heat, by monitoring the oxygen instantaneous balance, for the purpose of keeping all the heats with temperature percentage of the final C and iron yield, within the allowance limits preestablished for each type of heat.
- both the distance lance-metal bath and the flow of the oxygen jet are preestablished before the beginning of the refining, on the basis of considerations suggested by the experience and modified, during the refining itself, on the basis of the variation of some values, such as for example the intensity of some frequencies of the noise of the converter, or on account of the subjective impressions of the operating staff.
- This kind of operation which requires a great deal of attention and of skill from the staff, turns into an actual uncertainty as far as the obtainable results are concerned; in fact, the variation of the operational values considered, affects in various ways the trend of the refining, depending on the conditions existing in the converter, such as the temperature and composition of the bath and of the slag, the amount of slag, etc.
- the amount of oxygen to be blown, c in order to reach the required final value of carbon in the bath, is calculated a at a certain instant approaching the end point.
- the amount of oxygen 0 still to be blown, in order to reach the final required temperature is calculated. If 0, 0 everything is proceeding normally; if instead O 0, one must intervene either adding coolants or modifying the distance between the lance and the bath.
- the analysis of the flue gases at the stack supplies data affected by errors and it is not possible to determine, with sufficient precision, the various values and especially the constant k.
- the model takes practically into account the decarburization reaction, while the oxygen supplied through the lance, besides reacting with the carbon of the bath, reacts also with the other present slag-forming elements, as well as with the carbon monoxide.
- control of the refining pattern is performed by means of an analysis of the fumes at some location of the fume collecting and depuration system, far away from the converter and generally downstream of the waste heat boilers, and from these data a determination of the fumes analysis at the converter mouth is effected.
- Thesemethods are made questionable both by the large amounts of nitrogen present in the analyzed gases, coming from the air drawn into the hood and by the uncertainty inherent to the determination of the extent of the combustion reactions of CO into CO which occur outside of the converter.
- the object of the present invention is a refining process for metals, particularly for molten pig iron, in stationary or rotating oxygen converters, which allows to obviate the afore mentioned limitations, by continuously monitoring the refining process.
- the process which is the object of the present invention, is characterized by an uninterrupted control'technique of the refining, in which recourse is made to a dynamic model based on the instantaneous balance of the oxygen blown through the lance, calculated by means of the analysis of the discharge gases at the hood and at the stack, taking into account that the said oxygen reacts not only with the carbon of the bath, to form carbon monoxide, but also with other elements present in the bath, to form slag, and also, in the region above the bath, with the carbon monoxide obtained in the initial reaction, to form carbon dioxide.
- reaction (a) indicates how the decarburization is proceeding; reaction (b) allows to know how the thermal yield of the conversion itself is varying in the course of the refining; reaction (c) gives a measure of the amount of slag which is forming and this is of a great interest as far as the regularity of the refining and the control of the metallic yield are concerned.
- a metallurgical reference parameter is determined, as a function of the reactions occurring inside the converter during the refining, and of the amount of oxygen blown.
- the said reference parameter is defined by the following instantaneous experimental relationship:
- the type of the charge and the characteristics required for the steel at the end point are preestablished.
- the com puter chooses the relevant type of optimal curve and, during the blowing, receives the data which allow it to calculate A and B and thence the ratio K (A B)/Q m. Then it compares the value of this ratio at eac instant of the blowing to the optimal value preestablished for this instant, and if necessary, modifies the flow rate Q in such a way that the actual value of m be the nearest possible to the optimal value, or at least, be comprised within the preestablished variability range.
- the refining control is performed by means of a continuous series of samplings and analyses of the gases issuing from the converter, for the purpose of ascertainmg:
- the analysis of the gases at the converter mouth is performed by an indirect measurement, by sampling of the gas with a sampler within the hood, at adistance from the converter mouth ranging from 0.3 to 2.5 meters.
- the sampler which can be tilted from 0 to 90 in respect to the horizon, is thus introduced into the hood, in such way that its suction extremity is located approximately in the center of the hood itself, at a distance of 0 to 0.5 meters from the axis of the hood itself, and at a distance from the converter mouth ranging from 0.3 to 2.5 meters.
- the present invention it is also possible to perform the sampling of the gases at a distance from the converter mouth, lesser than 0.3 meters or even inside the converter itself, by means of a sampler directly incorporated in the blowing lance or attached to it, or separated from it and introduced into the converter mouth; however the preselected technique (that is the sampling of the gases in the hood) is to be preferred as being the most practical, since no further lifting apparatus for the sampler is necessary, and the chance that a spray of slag or liquid metal plugging the sampler is less probable; besides, the composition differences between the gases sampled inside the converter and those sampled with the suggested method are not too important.
- the gas sampled by the sampler is first depurated of dust and then conveyed to a continuous analyzer, of a conventional type, for CO and CO2 analysis and then to another continuous analyzer, also of a conventional type, for the analysis of oxygen.
- the nitrogen percentage possibly present is calculated as a complement to one hundred of the total of the C0, C02 and 02 per centages.
- the instantaneous values of the thus determined percentages, are recorded and simultaneously fed to an electronic computer.
- the gases are practically cold and saturated with water vapor, because of the countercurrent water cooling and are already depurated of dust; they are sampled by a sampler and conveyed directly into an analytical system, similar to that installed in the hood, and the analysis data thus obtained are also recorded and simultaneously fed to an electronic computer.
- thermoresistances In the stack, by means of a venturimeter-and a series of thermoresistances, measurements of the differential pressure AP, and of temperature T, are also performed. These data too are recorded and fed into the computer.
- the computer be gins to read, with a proper frequency, the values corresponding to the single measurements mentioned above.
- the computer elaborates the input data calculates the instantaneous value of m and compares it with the value preestablished for this particular type of refining at the corresponding instant.
- the calculation procedure is the following where the data a e indicated with:
- the computer compares continuously, during the blowing, the actual instantaneous value of m with that indicated by the preestablished curve, and gradually, by trials, prescribes the corrections to be possibly made to the distance between the lance and the bath and/or, preferably, to the flow rate of the oxygen delivered by said lance, in order to bring the instantaneous value of m back to the optimal value.
- FIG. 1 shows an optimal curve 1 of the parameter m, as a function of the blowing time, with the relevant allowance band or strip preestablished for a certain type of charge and for a certain requested result and delimited by the dashed lines 2 and 3.
- FIG. 2 shows the actual curve 4 of m, related to the heat indicated in Example I, superimposed over the curve of FIG. 1.
- FIG. 3 shows the actual curve 5 of m, relative to the curve of the heat indicated in Example 2 and superimposed over the curve of FIG. 1;
- FIG. 4 shows the actual curve 6 of m related to the heat indicated in the Example 3, superimposed over the curve of FIG. 1.
- the lance position is kept constant, while the oxygen flow rates are permitted to vary within an interval ranging from 600 to 800 Nm /min.
- the oxygen flow rate is 800 Nm /min
- the lance distance from the bath is still 1.50 meters.
- the automatic control is interrupted at about 2 minutes before the end point.
- the iron yield, at the allowance limits, is due to a sparking period during the first 3 minutes of blowing.
- the on-line computer on the basis of the previous data, indicated the charge composition as follows:
- the lance distance from the bath I was brought to 1.50 meters.
- the oxygen flow rate was maintained constant until the 17th minute, and thereafter was brought to 800 Nm /min.
- the final data of the metal bath are:
- a process for refining liquid pig iron into steel in a liquid bath comprising blowing a gas containing oxygen onto the bath, and analyzing the gas above the bath; the improvement comprising the steps of predetermining a desired graphical curve of m versus time on the basis of at least the actual initial and desired final physical characteristics of the bath, in which A being the instantaneous flow rate of the oxygen in said analyzed gas employed for the combustion of C into CO in Nm /min., B being the instantaneous flow rate of the oxygen in said analyzed gas used for the combustion of CO to CO in Nm /min., and Q being the instantaneous flow rate of the total oxygen in said blown gas in Nm /min., k being a constant; determining at a plurality of time intervals the actual instantaneous values of m on the basis of the physical characteristics of gas emitted from the bath; and varying the flow rate of said blown gas so as to decrease the difference between each said actual value of m and the predetermined value of m
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Manufacturing & Machinery (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Carbon Steel Or Casting Steel Manufacturing (AREA)
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT5160471 | 1971-07-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3847593A true US3847593A (en) | 1974-11-12 |
Family
ID=11275399
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US00267694A Expired - Lifetime US3847593A (en) | 1971-07-13 | 1972-06-29 | Process for refining metals, in particular liquid pig iron, in oxygen converters with continuous control of the operative procedure |
Country Status (4)
| Country | Link |
|---|---|
| US (1) | US3847593A (de) |
| AT (1) | AT338845B (de) |
| DE (1) | DE2234204B2 (de) |
| GB (1) | GB1394240A (de) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4148629A (en) * | 1976-08-04 | 1979-04-10 | Vereinigte Osterreichische Eisen- Und Stahlwerk-Alpine Montan Aktiengesellschaft | Process for controlling a steel refining process for steels having a carbon content within the range of 0.1 to 0.8 % by weight |
| RU2228370C1 (ru) * | 2003-03-20 | 2004-05-10 | ООО "Сорби стил" | Способ управления электроприводом исполнительных механизмов металлургических машин и агрегатов |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE10122922A1 (de) * | 2001-05-11 | 2002-11-14 | Mgp Instr Gmbh | Verfahren und Filtereinrichtung zur Fluktuatiuonsunterdrückung bei Meßdaten |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3372023A (en) * | 1964-05-23 | 1968-03-05 | Beteiligungs & Patentverw Gmbh | Method of monitoring and controlling the oxygen blowing process |
| US3475599A (en) * | 1965-03-30 | 1969-10-28 | Leeds & Northrup Co | Process measurement system for basic oxygen refining of steel |
| US3485619A (en) * | 1965-10-04 | 1969-12-23 | Beteiligungs & Patentverw Gmbh | Method of automatic control and adjustment of oxygen blowing processes |
| US3533778A (en) * | 1966-04-20 | 1970-10-13 | Centre Nat Rech Metall | Automatic control of pig iron refining |
| US3594155A (en) * | 1968-10-30 | 1971-07-20 | Allegheny Ludlum Steel | Method for dynamically controlling decarburization of steel |
| US3598386A (en) * | 1967-10-09 | 1971-08-10 | Crucible Steel Co America | Apparatus for making steel |
| US3700429A (en) * | 1970-01-05 | 1972-10-24 | Allegheny Ludlum Steel | Method of controlling vacuum decarburization |
| US3719469A (en) * | 1970-07-22 | 1973-03-06 | Allegheny Ludlum Ind Inc | Control for basic oxygen steelmaking furnace |
| US3720404A (en) * | 1967-06-27 | 1973-03-13 | Westinghouse Electric Corp | System for controlling carbon removal in a basic oxygen furnace |
| US3723099A (en) * | 1970-01-28 | 1973-03-27 | Sumitomo Metal Ind | Method for static control of an oxygen blown converter |
-
1972
- 1972-06-29 US US00267694A patent/US3847593A/en not_active Expired - Lifetime
- 1972-06-30 GB GB3068572A patent/GB1394240A/en not_active Expired
- 1972-07-12 AT AT600472A patent/AT338845B/de not_active IP Right Cessation
- 1972-07-12 DE DE2234204A patent/DE2234204B2/de active Pending
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3372023A (en) * | 1964-05-23 | 1968-03-05 | Beteiligungs & Patentverw Gmbh | Method of monitoring and controlling the oxygen blowing process |
| US3475599A (en) * | 1965-03-30 | 1969-10-28 | Leeds & Northrup Co | Process measurement system for basic oxygen refining of steel |
| US3485619A (en) * | 1965-10-04 | 1969-12-23 | Beteiligungs & Patentverw Gmbh | Method of automatic control and adjustment of oxygen blowing processes |
| US3533778A (en) * | 1966-04-20 | 1970-10-13 | Centre Nat Rech Metall | Automatic control of pig iron refining |
| US3720404A (en) * | 1967-06-27 | 1973-03-13 | Westinghouse Electric Corp | System for controlling carbon removal in a basic oxygen furnace |
| US3598386A (en) * | 1967-10-09 | 1971-08-10 | Crucible Steel Co America | Apparatus for making steel |
| US3594155A (en) * | 1968-10-30 | 1971-07-20 | Allegheny Ludlum Steel | Method for dynamically controlling decarburization of steel |
| US3700429A (en) * | 1970-01-05 | 1972-10-24 | Allegheny Ludlum Steel | Method of controlling vacuum decarburization |
| US3723099A (en) * | 1970-01-28 | 1973-03-27 | Sumitomo Metal Ind | Method for static control of an oxygen blown converter |
| US3719469A (en) * | 1970-07-22 | 1973-03-06 | Allegheny Ludlum Ind Inc | Control for basic oxygen steelmaking furnace |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4148629A (en) * | 1976-08-04 | 1979-04-10 | Vereinigte Osterreichische Eisen- Und Stahlwerk-Alpine Montan Aktiengesellschaft | Process for controlling a steel refining process for steels having a carbon content within the range of 0.1 to 0.8 % by weight |
| RU2228370C1 (ru) * | 2003-03-20 | 2004-05-10 | ООО "Сорби стил" | Способ управления электроприводом исполнительных механизмов металлургических машин и агрегатов |
Also Published As
| Publication number | Publication date |
|---|---|
| AT338845B (de) | 1977-09-12 |
| ATA600472A (de) | 1977-01-15 |
| DE2234204A1 (de) | 1973-02-01 |
| DE2234204B2 (de) | 1975-11-13 |
| GB1394240A (en) | 1975-05-14 |
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