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CA1289311C - Baking furance for electrodes - Google Patents

Baking furance for electrodes

Info

Publication number
CA1289311C
CA1289311C CA000516387A CA516387A CA1289311C CA 1289311 C CA1289311 C CA 1289311C CA 000516387 A CA000516387 A CA 000516387A CA 516387 A CA516387 A CA 516387A CA 1289311 C CA1289311 C CA 1289311C
Authority
CA
Canada
Prior art keywords
baking furnace
baking
refractory lining
casing
cooling chamber
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
CA000516387A
Other languages
French (fr)
Inventor
Erik Q. Dahl
Arnfinn Vatland
Olaf T. Vegge
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.)
Elkem ASA
Original Assignee
Elkem ASA
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 Elkem ASA filed Critical Elkem ASA
Application granted granted Critical
Publication of CA1289311C publication Critical patent/CA1289311C/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Classifications

    • HELECTRICITY
    • H05ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05BELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B7/00Heating by electric discharge
    • H05B7/02Details
    • H05B7/06Electrodes
    • H05B7/08Electrodes non-consumable
    • H05B7/085Electrodes non-consumable mainly consisting of carbon
    • H05B7/09Self-baking electrodes, e.g. Söderberg type electrodes
    • YGENERAL 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
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P10/00Technologies related to metal processing
    • Y02P10/25Process efficiency

Landscapes

  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Plasma & Fusion (AREA)
  • Furnace Details (AREA)
  • Tunnel Furnaces (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Feeding, Discharge, Calcimining, Fusing, And Gas-Generation Devices (AREA)
  • Baking, Grill, Roasting (AREA)
  • Manufacture And Refinement Of Metals (AREA)
  • Discharge Heating (AREA)
  • Ceramic Products (AREA)
  • Meat, Egg Or Seafood Products (AREA)
  • Liquid Crystal Substances (AREA)
  • Muffle Furnaces And Rotary Kilns (AREA)
  • Carbon And Carbon Compounds (AREA)

Abstract

ABSTRACT
The present invention relates to a baking furnace for continuous production of elongated carbon bodies having uniform cross section, the baking furnace being intended to be moved continuously or substantially continuously in relation to a casing containing unbaked carbonaceous electrode paste with a speed which corresponds to a preset baking speed for the carbon body.

The baking furnace comprises an outer steel shell (5) and a refractory lining (6) arranged on the inside of the shell (5), said refractory lining (6) defining a combustion chamber (7). A cooling chamber (16) is arranged between the upper part (15) of the refractory lining (6) and the casing (3). Above the cooling chamber (16) there is provided gas sealing means (23). An off-gas channel (11) is arranged below the refractory lining (16).

Description

~l~8~

The present invention relates to a baking furnace for continuous production of elongated carbon bodies with a substantially uniform cross section such as for example carbon electrodes for use in electric smelting furnaces, lining blocks, anode- and cathode elements in electrolytic cells for production of aluminium. The elongated carbon bodies may have any cross section, e.g. circular, rectangular or others.

method is known for production of elongated carbon bodies where unbaked carbonaceous electrode paste comprising a carbon material and a carbonaceous binder continuously is baked to a solid carbon body by charging the unbaked electrode paste into a casing having a cross section correspondinq to the cross section of the carbon body to be produced, and continuously or substantially continuously lowering the casing down through a baking urnace to which baking furnace heat energy is supplied.
It is further known to use a perforated casing whereby gases which evolve in the electrode paste by heating, flow from the electrode and into the baking furnace where they are combusted.

It has been observed that the gases which evolve during the heating of the electrode paste and flow into the baking furnace through the perforations in the casing, have a tendency to condense in the upper part of the baking furnace where the cold electrode casing containing cold electrode paste enters into the baking furnace. This condensate which consists of a large number of different hydrocarbon fractions, will eventually be carbonised in the upper paxt of the baking furnace and a layer of hard carbonized material will slowly build up and after some time, completely fill up the annulus between the baking fur-nace and the electrode casing. This will have the result that after operation of the furnace for some weeks it will not be possible to move the casing or the eleçtrode conse~uently relative to the baking furnace. The growth in this layer of hard carbonized material in the upper part of the baking furnace must therefore more or less continuously be observed and at a certain time the baking process has to be stopped and the baking furnace has to be dismantled in order to remove the layer of carbonized material. During removal of the layex of carbonized material, the baking zone in the carbon body is cooled, whereby an inhomogeneity is produced in the elongated carbon body.

If the baking furnace is operating in direct connection with an electric smelting furnace for production of a carbon electrode which is directly used in the smelting furnace, the operation of the smelting furnace has to be shut down during the removal of the layer of carbonized material in the baking furnace. This will result in loss of production from the smelting furnace and in addition there will be a high risk of electrode breakage when the part of the electrode containing the above mentioned in-homogeneity enters into the smelting furnace.

It is an object of the present invention to provide a baking furnace which prevents the build up of hard, carbonized material in the upper part of the baking furnace.

It is a further ob~ect of the present invention to provide an efficient gas sealing between the electrode casing and the upper part of the baking furnace in order to prevent gas leakages from the baking furnace to the environment.

Accordingly, the present invention relates to a baking furnace for continuous production of elongated carbon bodies having a substantially uniform cross section, wherein the baking furnace continuously or substantially continuously is moved relatively to the carbon body with a speed which corresponds to a preset baking speed for the carbon body.

According to the present invention the baking furnace comprises an outer shell made from steel and a refractory lining arranged on the inside of the shell which defines a combustion chamber about the carbon body which is being produced. A cooling chamber is arranged between the upper part of the refractory lining and the carbon body which is being produced, the lower part of the cooling chamber extending into the combustion chamber and the upper part of the cooling chamber e~tending above the refractory lining of the combustion chamber. In the lower part of the combustion chamber there is arranged a channel for the off-gases from the combustion chamber.

The cooling chamber preferably has internal channels for circulation of a cooling medium. Above the cooling chamber there is arranged a guide ring for guiding the carbon body through the baking furnace and a gas sealing to prevent gas leakages from the combustion chamber. The gas sealing .

~ ~9.~1L

preferably comprises a flexible gasket arranged between vertically arranged lower flanges which are affixed to a plate on the top of the cooling chamber and ver.ically arranged upper flanges which are affixed to another plate and where the distance between the upper and lower flanges and thereby the tightening of the gasket against the carbon body, can be adjusted by means of a plurality of bolts.

Further embodiments of the present invention will be evident from the claims.

The baking furnace according to the present invention will now be further described in connection with the drawings !
which shows a preferred embodiment of the present ', invention.

Figure 1 shows a vertical cut through a baking furnace according to the present invention, and;

Figure 2 shows an enlarged view oE a part of figure 1.

On figure 1 there is shown a baking furnace 1 for production of elongated carbon bodies 2. The baking furnace is arranged about a casing 3 for the carbon body 2.
The casing 3 has a cross section which corresponds to the cross section of the carbon body.

Unbaked carbonaceous electrode paste 4 which consists of a carbon material and a carbonaceous binder is charged into the casing 3. By heating of the electrode paste 4 in the baking furnace 1, the electrode paate is baked into a solid ~2139~

carbon body 2. The casing 3 is preferably perforated (not shown) in order to allow gases which evolve during the heating of the electrode paste to flow through the perforations and into the baking furnace.

The baking furnace 1 comprises an outer shell 5 and a refractory lining 6 defining a combustion chamber 7. The combustion chamber 7 is heated to the necessary baking temperature by means of at least one burner 8 for solid, liquid or gaseous fuel. The burner or burners 8 are preferably tangentially arranged in relation to the combustion chamber 7. The burner 8 has supply pipes 9 and 10 for fuel and combustion air. Below the refractory lining 6 there is arranged a channel 11 for off-gases from the baking furnace 1. The off-gas is sucked out from the channel 11 through an off-gas pipe 12. In the off-gas pipe 12 there is arranged a valve 13 for regulating the volume of off-gas from the baking furnace.

The channel 11 has a central opening with a diameter slightly greater than the diameter of the baked carbon body 2. Between the channel 11 and ,the casing 3 for the carbon body 2 there will therefore be a slot 14. When the baking furnace 1 is in operation, environmental air is sucked in through the slot 14 and thereby provides a seal so that gases from the combustion chamber 8 will not escape through the slot 14.

In the upper part 15 of the refractory lining 6 of the baking furnace 1, there is provided an opening for the casing 3. This opening has a somewhat greater cross section than the cross section of the casing 3.,,,In the annular slot between the upper part 15 of the refractory lining 6 and the casing 3 there is arranged a cooling . . .

~ ~9-~ t chamber 16 for circulation of a cooling medium. The cooling chamber 16 has supply pipe 17 and return pipe 18 for the cooling medium which preferably is water. The cooling chamber 16 may be divided into sections and each section may be provided with internal walls (not shown) in order to ensure a proper flow of cooling medium through the cooling chamber 16.

The cooling chamber 16 is arranged in such a way that its lower end is at about the same level as the lower end of the upper part 15 of the refractory lining 6 as shown on figure 1. The cooling chamber 16 extends upwardly to a level at least above the upper end of the upper part 15 of the refractory lining 6.

The cooling chamber 16 is affixed to the outer shell 5 via an annular plate 20 which is secured to the shell 5 by means of bolts 21.

If the baking furnace 1 is used for baking a carbon electrode in direct connection with an electric smelting furnace, electric insulation 25 is preferably inserted between the shell 5 on the baking furnace 1 and the annular plate 20.

Above the cooling chamber 16 there is secured a guide ring 22 made from rod iron or the like. The purpose of guide ring 22 is to guide the casing relatively to the baking furnace. In the area above the guide ring 22 there is arranged gas sealing means 23 for preventing gas leakages between the casing 3 and the baking furnace 1.

1~39~

The gas sealing means 23 is shown in enlarged scale on figure 2. The gas sealing means 23 comprises a lower annular plate 24 which is secured to the cooling chamber 16. To the plate 24 there are affixed two annular vertically running flanges 26 and 27. Between the flanges 26 and 27 there is provided a flexible gasket 28 made of a material having a high melting point. The upper end of the gasket 28 is arranged between annular vertical flanges 29 and 30 which are connected to a second annular plate 31.
The second annular plate 31 is affixed to the flange 26 by means of a plurality of threaded bolts 32 having handles 33. By adjusting the distance between the first plate 24 and the second plate 31 by operating the handles 33, the flexible gasket 28 is tightened or loosened. The gasket 28 can be adjusted locally about the circumference of the casing 3 by operations of the handles 33.

In operation the baking furnace 1 is continuously or substantially continuously moved relative to the casing 3 with a speed corresponding to the preset baking speed for the carbon body 2. When the casing 3 with the unbaked electrode paste 4 enters into the baking furnace 1, the electrode paste is heated and the electrode paste then becomes liquid whereafter the paste is baked into a solid carbon body.

During the baking, carbonaceous gases evolve in the electrode paste. These gases flow into the baking furnace 1 through perforations in the casing 3 and most of the gases are immediately cumbusted by the combustion air which is supplied to the baking furnace.

A part of the gases will, however, condense on the cooling area 19 on the lower vertical part of the cooling chamber 16 where the temperature is kept below 400C by the cooling medium circulating in the cooling chamber. As the temperature in the baking chamber is in the interval between 700 and 1300C, the part of the gases which come into contact with the cooling area 19 will condense. The temperature in the area of the cooling chamber 16 is, however, so low that the conden$ed gases will not be carbon-ized. The condensate from the gases will therefore drop down into the combustion chamber where it will immediately be combusted. The cooling chamber further provides that the gas in the annulus between the casing 3 and the cooling chamber is kept at a lower temperature. The gasket 28 is thereby protected against high temperature exposure. The lifetime for the gasket 28 will thereby be increased.

By the present invention a baking furnace is provided which can be operated for lo~g periods ~
without operation difficulties due to build ups of layers of carbonized material. Further, a very good gas seal between the carbon body and the baking furnace is obtained, thereby minimizing the possibility for leakage of hazardous gases from the baking furnace to the environment.

" ': ' ' .:
.

Claims (8)

1. A baking furnace for continuous production of elongated carbon bodies having uniform cross-section, said baking furnace being intended to be moved continuously or substantially continuously in relation to a casing containing unbaked carbonaceous electrode paste with a speed which corresponds to a preset baking speed for the carbon body, c h a r a c t e r i z e d i n that the baking furnace (1) comprises an outer steel shell (5) and a refractory lining (6) arranged on the inside of the shell (5) said refractory lining (6) defining a combustion chamber (7), a cooling chamber (16) arranged between the upper part (15) of the refractory lining (6) and the casing (3), gas sealing means (23) arranged above the cooling chamber (16) and an off-gas channel (11) arranged below the refractory lining (6).
2. Baking furnace according to claim 1, c h a r a c t e r i z e d i n that the lower end (19) of the cooling chamber (16) is situated at substantially the same vertical level as the lower end of the upper part (15) of the refractory lining (6).
3. Baking furnace according to claim 1, c h a r a c t e r i z e d i n that a guide ring (22) for guiding the casing (3) is arranged above the cooling chamber (16).
4. Baking furnace according to claim 1, c h a r a c t e r i z e d i n that the gas sealing means (23) comprises a flexible gasket (28) which is arranged between vertical lower flanges (26, 27) affixed to a plate (24) and vertical upper flanges (29, 30) affixed to a plate (31), and that the distance between the lower flanges (26, 27) and the upper flanges (29, 30) can be adjusted.
5. Baking furnace according to claim 4, c h a r a c t e r i z e d i n that the distance between the lower flanges (26, 27) and the upper flanges (29, 30) is adjustable by means of a plurality of bolts (32).
6. Baking furnace according to claim 1, c h a r a c t e r i z e d i n that the baking furnace has at least one burner (8) for solid, liquid or gaseous fuel.
7. Baking furnace according to claim 6, c h a r a c t e r i z e d i n that the burner (8) is tangentially arranged relative to the combustion chamber (7).
8. Baking furnace according to claim 1, c h a r a c t e r i z e d i n that the baking furnace (1) is equipped with at least one pipe (10) for supply of combustion air to the combustion chamber (7).
CA000516387A 1985-08-22 1986-08-20 Baking furance for electrodes Expired - Lifetime CA1289311C (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
NO853320A NO157078C (en) 1985-08-22 1985-08-22 Electrode baking oven.
NO853,320 1985-08-22

Publications (1)

Publication Number Publication Date
CA1289311C true CA1289311C (en) 1991-09-24

Family

ID=19888440

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000516387A Expired - Lifetime CA1289311C (en) 1985-08-22 1986-08-20 Baking furance for electrodes

Country Status (30)

Country Link
JP (2) JPS6247988A (en)
CN (1) CN1005285B (en)
AU (1) AU582008B2 (en)
BE (1) BE905309A (en)
BR (1) BR8603977A (en)
CA (1) CA1289311C (en)
CH (1) CH671667A5 (en)
CS (1) CS274280B2 (en)
DD (1) DD248862A5 (en)
DE (1) DE3626889A1 (en)
ES (1) ES2001112A6 (en)
FI (1) FI82309C (en)
FR (1) FR2586472B1 (en)
GB (1) GB2179727B (en)
GR (1) GR862165B (en)
IN (1) IN168474B (en)
IS (1) IS1349B6 (en)
IT (1) IT1197849B (en)
MX (1) MX168408B (en)
NL (1) NL187331C (en)
NO (1) NO157078C (en)
NZ (1) NZ217238A (en)
PH (1) PH22714A (en)
PL (1) PL153132B1 (en)
PT (1) PT83207B (en)
SE (1) SE462313B (en)
SU (1) SU1440358A3 (en)
TR (1) TR22597A (en)
YU (1) YU44926B (en)
ZA (1) ZA865788B (en)

Families Citing this family (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE8811140U1 (en) * 1988-09-03 1988-10-13 Wilkinson Sword GmbH, 5650 Solingen Razor or thinning knife
IT1243899B (en) * 1989-11-14 1994-06-28 Elkem Technology PROCEDURE AND MEANS FOR THE CONTINUOUS PRODUCTION OF COAL BODIES.
FR2656361B1 (en) * 1989-12-22 1992-04-30 Manouvrier Pierre WALL WITH VARIABLE GEOMETRY.
DE10323203A1 (en) * 2003-05-22 2004-12-23 Wacker Polymer Systems Gmbh & Co. Kg Use of silane-functional polyvinyl alcohols in primers for release papers and films
CN104041180B (en) * 2011-11-11 2016-02-03 电化株式会社 End detecting device and self-baking electrode upper end management method on self-baking electrode
WO2019233549A1 (en) * 2018-06-04 2019-12-12 Rheinfelden Carbon Gmbh & Co. Kg Self-baking electrode
CN109297851B (en) * 2018-11-14 2020-03-31 西安交通大学 Simulation experiment device and test method for high-temperature calcination reaction of fixed bed

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2090693A (en) * 1934-12-28 1937-08-24 Carborundum Co Method of graphitizing carbon bodies
FR1510840A (en) * 1966-07-05 1968-01-26 Kaiser Ind Corp Process for the preparation of a continuous electrically conductive element
FR2534240A1 (en) * 1982-10-06 1984-04-13 Savoie Electrodes Refract CONTINUOUS PROCESS FOR GRAPHITIZING LONG CARBON PRODUCTS AND OVEN FOR CARRYING OUT SAID METHOD
CS276710B6 (en) * 1983-12-02 1992-08-12 Elkem As Process of continuous manufacture of elongated carbon bodies

Also Published As

Publication number Publication date
NO853320L (en) 1987-02-23
GR862165B (en) 1986-12-23
IS1349B6 (en) 1989-03-20
PL153132B1 (en) 1991-03-29
IT8621427A0 (en) 1986-08-06
IN168474B (en) 1991-04-13
MX168408B (en) 1993-05-24
GB2179727B (en) 1989-08-02
NZ217238A (en) 1988-05-30
PH22714A (en) 1988-11-28
TR22597A (en) 1987-12-16
NO157078B (en) 1987-10-05
NO157078C (en) 1988-01-13
DE3626889C2 (en) 1987-07-09
BR8603977A (en) 1987-03-31
CS613186A2 (en) 1990-09-12
SU1440358A3 (en) 1988-11-23
FI82309B (en) 1990-10-31
IS3127A7 (en) 1987-02-23
JPS6247988A (en) 1987-03-02
SE462313B (en) 1990-05-28
SE8603514L (en) 1987-02-23
FI863158A7 (en) 1987-02-23
JPS6246184A (en) 1987-02-28
BE905309A (en) 1986-12-16
DE3626889A1 (en) 1987-03-05
CH671667A5 (en) 1989-09-15
GB8620241D0 (en) 1986-10-01
NL8602085A (en) 1987-03-16
IT8621427A1 (en) 1988-02-06
CN1005285B (en) 1989-09-27
AU6168386A (en) 1987-02-26
CN86105225A (en) 1987-02-18
YU44926B (en) 1991-04-30
PT83207A (en) 1986-09-01
IT1197849B (en) 1988-12-06
FR2586472A1 (en) 1987-02-27
NL187331B (en) 1991-03-18
CS274280B2 (en) 1991-04-11
JPH0247679B2 (en) 1990-10-22
SE8603514D0 (en) 1986-08-20
PL261089A1 (en) 1987-06-29
FI82309C (en) 1991-02-11
DD248862A5 (en) 1987-08-19
ES2001112A6 (en) 1988-04-16
AU582008B2 (en) 1989-03-09
YU144586A (en) 1988-12-31
PT83207B (en) 1992-10-30
NL187331C (en) 1991-08-16
FR2586472B1 (en) 1988-09-09
GB2179727A (en) 1987-03-11
FI863158A0 (en) 1986-08-01
ZA865788B (en) 1988-03-30

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