US3570831A - Process and arrangement for evacuation of gas developed during a continuous metal refining operation - Google Patents

Process and arrangement for evacuation of gas developed during a continuous metal refining operation Download PDF

Info

Publication number
US3570831A
US3570831A US757954A US75795468A US3570831A US 3570831 A US3570831 A US 3570831A US 757954 A US757954 A US 757954A US 75795468 A US75795468 A US 75795468A US 3570831 A US3570831 A US 3570831A
Authority
US
United States
Prior art keywords
gas
conduit
arrangement
refining
vessel
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
Application number
US757954A
Other languages
English (en)
Inventor
Jean Rouanet
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Institut de Recherches de la Siderurgie Francaise IRSID
Original Assignee
Institut de Recherches de la Siderurgie Francaise IRSID
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Institut de Recherches de la Siderurgie Francaise IRSID filed Critical Institut de Recherches de la Siderurgie Francaise IRSID
Application granted granted Critical
Publication of US3570831A publication Critical patent/US3570831A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

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
    • C21C5/56—Manufacture of steel by other methods
    • C21C5/567—Manufacture of steel by other methods operating in a continuous way
    • 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
    • C21C5/38—Removal of waste gases or dust
    • C21C5/40—Offtakes or separating apparatus for converter waste gases or dust
    • 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
    • Y02P10/25—Process efficiency

Definitions

  • U 3 Sheets-Sheet 3 United States Patent O 3,570,831 PROCESS AND ARRANGEMENT FOR EVACUA- TION OF GAS DEVELOPED DURING A CON- TINUOUS METAL REFHNING OPERATION Jean Rouanet, Metz, France, assignor to Institut de mecanics de la Siderurgie Francaise, St. Germain-en- Laye, Yvelines, France Filed Sept. 6, 1968, Ser. No. 757,954 Claims priority, application France, Apr.
  • the present invention relates to a process and an arrangement for evacuation of gas, more particularly of gas produced in a refining apparatus during a continuous refining of liquid metal therein.
  • the evacuation of gas developed during operation of a continuous metal refining apparatus causes sometimes problems which, due to the structure of the refining apparatus, are difficult to solve with gas discharge means known in the art.
  • apparatus for continuously refining metal it is necessary not only to continuously discharge the gas developed during the refining operation, but also to continuously discharge the refined metal and the slag developed during refining process.
  • the vessels of the refining apparatus require therefore at least one opening for the discharge of gas therefrom which develops during the refining operation and a plurality of additional openings, at least one of which, especially the opening which provides for the discharge of slag is in permanent communication with the outer atmosphere.
  • evacuation means which permit to collect or capture the entire gas developing during the refining process and to avoid raising of the pressure in the interior of the vessels of the refining apparatus in such a manner that would lead to a loss of gas so that in consequence thereof part of the carbon contained in the gas in the form of CO or CO would not be encompassed by the analysis of the gas.
  • 'It is also an object of the present invention to provide for a process and an arrangement of the aforementioned kind in which also sucking of the air from the outer atmosphere through the slag discharge opening into the interior of the apparatus is reduced to a minimum and preferably held to substantially zero.
  • the process according to the present invention of evacuating gas developed during a continuous metal refining operation is used in a metal refining apparatus including a first or reaction vessel and a last vessel communicating with the reaction vessel and having a slag discharge opening communicating with the outer atmosphere, in which the reaction vessel and the last vessel are provided with gas discharge conduits for discharging gas developing during the refining operation therefrom, and the process comprises the steps of exhausting gas through the conduit communicating with the reaction vessel at an amount q which is inferior to the total amount of gas Q developing during the refining operation, and simultaneously regulating the amount of gas exhausted through the conduit communicating with the last vessel to a value q substantially equal to the difference Q-q so as to obtain in the region of the slag discharge opening an equilibrium between the gas pressure in the interior of the apparatus and the pressure of the outer atmosphere to thus avoid any loss of gas through the slag discharge opening.
  • the amount of gas discharged through the aforementioned conduits may be automatically regulated by means of control means in dependence on the value of Ap.
  • the arrangement according to the present invention for carrying out the above-mentioned process may include a pair of gas discharge conduits respectively communicating at one of the ends therof with the reaction vessel and the last vessel, a common conduit communieating at one end with the other ends of the pair of gas discharge conduits, means provided in said common conduit and in at least one of the pair of gas discharge conduits for regulating the amount of gas passing therethrough, means for continuously measuring the difference Ap between the presure [1 of the outer atmosphere in the region of the slag discharge opening and the gas pressure 12 in the interior of the last vessel in this region, and control means cooperating with the measuring means and the regulating means in the conduits for automatically controlling the regulating means in dependence on the pressure difference Ap measured by the measuring means.
  • the aforementioned common conduit may communicate at the other end thereof with a hood which is not fluid-tightly joined to the other end of the common conduit.
  • the aforementioned common conduit may be connected by means of a conduit directly with an exhaust ventilator.
  • the aforementioned common conduit may be arranged substantially vertically so that exhaustion of gas therethrough is caused by the chimney effect provided by the common conduit.
  • the regulating means in the conduits may be constituted by vanes.
  • the aforementioned regulating means may be constituted by ejector means for ejecting a neutral gas into the conduits.
  • the invention permits, by adjusting the amount of gas exhausted through the conduits, to obtain an equilibrium between the gas pressure in the interior of the apparatus in the region of the slag discharge opening and the pressure of the outer atmosphere in the aforementioned region in order to collect the total amount of gas developed during the refining process.
  • the aforementioned equilibrium will obviously be realized when the total amount of gas discharged through the conduits will be equal to the total amount of gas which is produced during the refining process.
  • the equilibrium between the aforementioned pressures will assure that aspiration of air from the outer atmosphere through the slag discharge opening will be reduced to a minimum or become zero. In this way it is possible to conduct the gases developed during the refining process out of the apparatus without causing a combustion of the gases, which will produce the same advantages as are derivable from the conducting of gases without combustions in converters by means know in the art.
  • the invention also permits, by properly controlling the regulating means in the gas discharge conduits to limit the amount of gas discharged through the conduit connected to the first vessel of the apparatus and to such through the aforementioned conduit only a fraction q of the total amount Q of the gas developed during the refining process, while the remaining fraction q is stroked out through the conduit connected to the last vessel of the refining apparatus.
  • the reaction vessel a circulation of the hot gas created in the first vessel of the refining apparatus, called the reaction vessel, and such circulation may be adjusted in any manner desired as a function of the refining process.
  • This feature is especially important since the circulation of the hot gases permits to maintain the interior of the vessels of the apparatus and the material contained therein at a temperature best suited for the refining process and to improve in this way the thermal balance of the apparatus. Especially, it is possible, due to the calories supplied by the hot gas stream to maintain the slag produced at a sufificiently elevated temperature so that the slag will remain fluid and easy to evacuate.
  • one of the gas discharge conduits for example the conduit connected to the reaction vessel may be deprived of means for regulating the amount of gas passing therethrough. Since the total amount Q of gas produced during a normal refining operation is known, it is possible to fix in advance the amount of gas q passing through the aforementioned conduit at a value considerably lower than Q, for instance three-quarters of Q. Since the amount of gas to be discharged through the aforementioned conduit is constant and determined in advance, it will sufiice to construct the aforementioned conduit with a diameter such that the pressure drop in this conduit will limit the amount of gas discharged therethrough substantially to the aforementioned amount q.
  • control means in this case have to control only the regulating means in the conduit connected to the last vessel of the apparatus and eventually also to the regulating means in the common conduit so as to adapt the total amount of gas discharged through the conduits to the total amount of gas produced and also to follow small variations of the total amount of the valve Q.
  • the arrangement of the common conduit which is connected to the gas discharge conduits respectively communicating with the first and the last vessel of the apparatus may likewise be made in different ways.
  • the common conduit may for instance be rather short and discharge into a hood, as commonly used in converters while the hood is by means of another conduit connected to an exhaust ventilator. It is also possible to connect the common conduit directly by a conduit forming a continuation of the common conduit to an exhaust ventilator.
  • the common conduit it is possible to use for the common conduit a conduit which is relatively long and vertically arranged so that the chimney effect produced by the COIllmon conduit will provide an aspiration sufiicient for evacuation of the total amount of gas produced during the refining operation.
  • FIG. 1 is a schematic sectional side view of the apparatus according to the present invention.
  • FIGS. 24 respectively illustrate in part variations of the arrangement shown in FIG. 1.
  • the apparatus for continuously refining pig iron into steel mainly comprises a first vessel into the bottom of which the metal M to be refined is introduced through an inlet passage 10' and into which refining agents are injected under pressure by means of a lance 11 extending downwardly through the roof of the vessel 10.
  • the slag metal foam formed in this way in the vessel 10 is evacuated from the latter by overflow into a second or last vessel 12 communicating with the first vessel 10 through the opening 12' in which the slag metal foam separates in a continuous metal phase and a slag phase floating thereon and the slag floating on the metal is continuously discharged through a slag discharge opening 13 which communicates with the outer atmosphere, while the metal is continuously discharged through an opening 13' in the bottom of the vessel 12.
  • the arrangement for evacuation of the gas produced during the refining process is constituted according to the present invention by a first conduit 14 communicating at one end thereof with an upper portion of the vessel 10 and by a second conduit 15 communicating at one end thereof with an upper portion of the vessel 12 in the region of the slag discharge opening 13 of the latter.
  • the two gas discharge conduits 14 and 15 are connected at the other ends thereof to a common conduit 16 which extends in upward direction and which is provided in the interior thereof with means for regulating the flow of gas therethrough which, in the arrangement shown in FIG. 1, are constituted by a vane 17 turnable about an axis 17' so as to restrict more or less the open cross section of the common conduit 16.
  • the conduit 16 discharges at its upper end into a hood 18 connected by a conduit 19 to an exhaust ventilator 20.
  • the amount of evacuated gas is regulated by the vane 17 to a valve equal to the amount Q developed during the refining operation in the apparatus.
  • the cross section ".s of the conduit 14 is determined in such a manner to be considerably smaller than a section which would normally permit the evacuation of the total amount of gas produced during the refining operation in the reaction vessel 10 through the conduit 14.
  • the conduit 14 is arranged for the discharge of an amount of gas q considerably smaller than the total amount of gas Q normally developed during the refining operation. Therefore, a slight overpressure will be created in the vessel 10 and part of the gas developed therein will be passed into the decanting vessel 12. This part corresponds to an amount equal to Q-q.
  • the conduit 15 is provided with means for regulating the amount of gas passing therethrough, and these means are shown in FIG. 1 as a vane 2-2 turnable about an axis 22.
  • the cross section S of the conduit 15 has a larger dimension than the cross section .s of the conduit 14.
  • the cross section 8" is chosen in such manner so that, when the vane 22 is in fully open position, a strong sucthe gas made by an analyzer 23 connected for instance to the conduit 19, as shown in FIG. 1, will therefore be representative of the gas produced during the refining operation and it is possible to control in this way the refining operation With great precision.
  • the aforementioned position of the vane 22 will correspond to an equilibrium between the pressure p, in the interior of the decanting vessel 12 in the region of the slag discharge opening 13 and the pressure p,, of the outer atmosphere in this region.
  • the vane 22 has therefore to be positioned in dependence on the value of Ap.
  • the latter position has a certain advantage, especially if the refining operation is subjected to abnormal variations.
  • Proper positioning of the vanes 17 and 22 is preferably made fully automatic.
  • control means including a regulator 25 of known construction, not forming part of the present invention, connected at the one hand to the pressure sensing means 24a and 24b and receiving from the latter a signal corresponding to Ap, and on the other hand to servo motors, or the like, 26 and 27 respectively connected, in a manner known per se and not forming part of the present invention, to the vanes 22 and 117 so as to position the latter in dependence on the pressure difference sensed by the pressure sensing means 24a and 24b.
  • the position of the two vanes relative to each other will determine the amount of hot gas which, coming from the reaction vessel 10, will circulate through the decanting vessel 12.
  • This arrangement has the advantage of great simplicity and it can be used for instance if it is not necessary to remove the dust from the gas or when it is not desired to recover the gas produced during the refining operation.
  • vanes 117 and 2 It is also possible to replace the vanes by other appropriate elements, for instance by ejectors.
  • ejectors 28 and 29 are respectively arranged in the common conduit 16 and in the conduit '15. These ejectors are supplied with nitrogen under pressure from a source not shown in the drawing.
  • the amount of nitrogen respectively blown through the ejectors 28 and 29 is respectively regulated by valves 30 and 31, the position of which may be controlled by servo motors 32 and 33 which in turn are operated from the regulator 25 in the manner as described above in connection with the vanes 117 and 2 2.
  • a refining apparatus for continuous metal refining and including a reaction vessel and a last vessel communicating with the reaction vessel and being provided at an end thereof distant from the reaction vessel with a slag discharge opening communicating with the atmosphere; an arrangement for evacuating gas developing during refining of metal in the apparatus without any loss of gas through said slag discharge opening, said arrangement comprising a pair of gas discharge conduits respectively communicating at one of the ends thereof with said reaction vessel and said last vessel; a common conduit communicating at one end with the other ends of said pair of gas discharge conduits; means provided in said common conduit and in at least one of said pair of gas discharge conduits for regulating the amount of gas passing therethrough; means for continuously measuring the difference A between the gas pressure p in the interior of said last vessel in the region of said slag discharge opening and the pressure 2 of the outer atmosphere in the region of the slag discharge opening; and control means cooperating with said measuring means and said regulating means in said conduits for automatically controlling said regulating means in dependence on the pressure difference Ap measured by said measuring means.
  • said regulating means are constituted by vanes respectively mounted in said conduits movable between a plurality of positions by said control means in which said vanes restrict the cross section of said conduits to a varying degree.
  • said regulating means are constituted by ejector means for ejecting a neutral gas respectively into said conduits, and wherein said control means cooperate with said ejector means for regulating the amount of neutral gas ejected into said conduits, respectively.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Environmental & Geological Engineering (AREA)
  • Waste-Gas Treatment And Other Accessory Devices For Furnaces (AREA)
  • Filling Or Discharging Of Gas Storage Vessels (AREA)
  • Treating Waste Gases (AREA)
  • Furnace Details (AREA)
US757954A 1967-09-18 1968-09-06 Process and arrangement for evacuation of gas developed during a continuous metal refining operation Expired - Lifetime US3570831A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR121349 1967-09-18
FR150385A FR95403E (fr) 1967-09-18 1968-05-03 Dispositif de captage des gaz produits au cours des opérations d'affinage continu d'un métal liquide.

Publications (1)

Publication Number Publication Date
US3570831A true US3570831A (en) 1971-03-16

Family

ID=26179500

Family Applications (1)

Application Number Title Priority Date Filing Date
US757954A Expired - Lifetime US3570831A (en) 1967-09-18 1968-09-06 Process and arrangement for evacuation of gas developed during a continuous metal refining operation

Country Status (10)

Country Link
US (1) US3570831A (ro)
AT (1) AT285644B (ro)
BE (1) BE720563A (ro)
FR (1) FR95403E (ro)
GB (1) GB1200409A (ro)
LU (1) LU56877A1 (ro)
OA (1) OA02888A (ro)
PL (1) PL80349B1 (ro)
RO (1) RO54516A (ro)
SE (1) SE335746B (ro)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3707069A (en) * 1970-10-13 1972-12-26 Air Pollution Ind Gas collector for steel furnace
US4865643A (en) * 1988-02-17 1989-09-12 Globe Metallurgical, Inc. Smelting process for making elemental silicon and alloys thereof, and apparatus therefor
US5104096A (en) * 1988-02-17 1992-04-14 Globe Metallurgical Inc. Smelting apparatus for making elemental silicon and alloys thereof
US5265117A (en) * 1991-05-22 1993-11-23 Unimetal, A French Body Corporate Method of exhausting gases and fumes from an electric arc furnace utilizing additional inlet gas duct ensuring constant pressure

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3707069A (en) * 1970-10-13 1972-12-26 Air Pollution Ind Gas collector for steel furnace
US4865643A (en) * 1988-02-17 1989-09-12 Globe Metallurgical, Inc. Smelting process for making elemental silicon and alloys thereof, and apparatus therefor
US5104096A (en) * 1988-02-17 1992-04-14 Globe Metallurgical Inc. Smelting apparatus for making elemental silicon and alloys thereof
US5265117A (en) * 1991-05-22 1993-11-23 Unimetal, A French Body Corporate Method of exhausting gases and fumes from an electric arc furnace utilizing additional inlet gas duct ensuring constant pressure
US5291513A (en) * 1991-05-22 1994-03-01 Unimetal Method and device for exhausting gases or fumes from a metallurgical container and an electric furnace provided with said exhaust device

Also Published As

Publication number Publication date
DE1758976A1 (de) 1972-02-10
SE335746B (ro) 1971-06-07
RO54516A (ro) 1973-06-11
OA02888A (fr) 1970-12-15
LU56877A1 (ro) 1968-12-24
BE720563A (ro) 1969-02-17
GB1200409A (en) 1970-07-29
AT285644B (de) 1970-11-10
PL80349B1 (ro) 1975-08-30
FR95403E (fr) 1970-11-06

Similar Documents

Publication Publication Date Title
US3154406A (en) Exhaust for steel converter
KR100662895B1 (ko) 함(含)크롬 용탕의 정련 방법 및 정련 장치
US3116999A (en) Method and apparatus for degassing liquids in a vacuum
US3367396A (en) Installation for the vacuum treatment of melts, in particular steel melts, and process for its operation
US3570831A (en) Process and arrangement for evacuation of gas developed during a continuous metal refining operation
GB1193458A (en) Process and Apparatus for Continuously Degassing Molten Metals
US4604137A (en) Method and apparatus for controlled melt refining
US3332676A (en) Regulation of the collection of gases from the oxygen refining pig iron
US3998626A (en) Method for air pollution control combined with safe recovery and control of gases from a bottom-blown steel converter vessel
CA2009923C (en) A process and an apparatus for the vacuum processing of metals
US3236635A (en) Method for degassing molten metal
US3145095A (en) Method and apparatus for continuously tapping and degassing molten metal into ingot molds
US4036479A (en) Cupola furnace
US3976473A (en) Method for producing an extremely low carbon and nitrogen steel in a vacuum refining apparatus
US3759700A (en) Process of refining metal melts by supersonic oxygen blow
US4104057A (en) Method for making low carbon high chromium alloyed steels
US3333839A (en) Apparatus for recovering unburned gases issued from metal refining furnaces
US4415142A (en) Apparatus for handling converter gas
US3194651A (en) Process and apparatus for recovering waste gases from converters in steel works
US4723762A (en) Apparatus for sealing the skirt of a converter waste gas recovery system
US3202409A (en) Apparatus for degassing molten metals
US3681052A (en) Method for controlling the treatment of exhaust gases in oxygen top-blowing converter
US4427183A (en) Gas control system for steel-making converters
US3418109A (en) Method for producing steel by an oxygen lance
JPH101716A (ja) 減圧精錬炉の減圧装置