US3828107A - Plasma smelting furnace - Google Patents

Plasma smelting furnace Download PDF

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Publication number
US3828107A
US3828107A US00142614A US14261471A US3828107A US 3828107 A US3828107 A US 3828107A US 00142614 A US00142614 A US 00142614A US 14261471 A US14261471 A US 14261471A US 3828107 A US3828107 A US 3828107A
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United States
Prior art keywords
furnace
plasma
refractory
smelting
gas
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
US00142614A
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English (en)
Inventor
S Sone
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.)
Daido Steel Co Ltd
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Daido Steel Co Ltd
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Filing date
Publication date
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27D—DETAILS OR ACCESSORIES OF FURNACES, KILNS, OVENS, OR RETORTS, IN SO FAR AS THEY ARE OF KINDS OCCURRING IN MORE THAN ONE KIND OF FURNACE
    • F27D11/00—Arrangement of elements for electric heating in or on furnaces
    • F27D11/08—Heating by electric discharge, e.g. arc discharge
    • A—HUMAN NECESSITIES
    • A44—HABERDASHERY; JEWELLERY
    • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
    • A44C17/00—Gems or the like
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J19/00—Chemical, physical or physico-chemical processes in general; Their relevant apparatus
    • B01J19/08—Processes employing the direct application of electric or wave energy, or particle radiation; Apparatus therefor
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/02—Fixed-bed gasification of lump fuel
    • C10J3/06—Continuous processes
    • C10J3/18—Continuous processes using electricity
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/02—Fixed-bed gasification of lump fuel
    • C10J3/20—Apparatus; Plants
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/57—Gasification using molten salts or metals
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J3/00—Production of combustible gases containing carbon monoxide from solid carbonaceous fuels
    • C10J3/72—Other features
    • C10J3/74—Construction of shells or jackets
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B14/00—Crucible or pot furnaces
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B14/00—Crucible or pot furnaces
    • F27B14/08—Details peculiar to crucible or pot furnaces
    • F27B14/14—Arrangements of heating devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F27—FURNACES; KILNS; OVENS; RETORTS
    • F27B—FURNACES, KILNS, OVENS, OR RETORTS IN GENERAL; OPEN SINTERING OR LIKE APPARATUS
    • F27B3/00—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces
    • F27B3/08—Hearth-type furnaces, e.g. of reverberatory type; Tank furnaces heated electrically, with or without any other source of heat
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2200/00—Details of gasification apparatus
    • C10J2200/09—Mechanical details of gasifiers not otherwise provided for, e.g. sealing means
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/09—Details of the feed, e.g. feeding of spent catalyst, inert gas or halogens
    • C10J2300/0953—Gasifying agents
    • C10J2300/0956—Air or oxygen enriched air
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/12—Heating the gasifier
    • C10J2300/123—Heating the gasifier by electromagnetic waves, e.g. microwaves
    • C10J2300/1238—Heating the gasifier by electromagnetic waves, e.g. microwaves by plasma
    • C—CHEMISTRY; METALLURGY
    • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
    • C10J—PRODUCTION OF PRODUCER GAS, WATER-GAS, SYNTHESIS GAS FROM SOLID CARBONACEOUS MATERIAL, OR MIXTURES CONTAINING THESE GASES; CARBURETTING AIR OR OTHER GASES
    • C10J2300/00—Details of gasification processes
    • C10J2300/12—Heating the gasifier
    • C10J2300/1246—Heating the gasifier by external or indirect heating

Definitions

  • the Present invention discloses a Plasma smelting h nace which is formed by enclosing the outside of a re- 52 us. (:1 13/1, 13/31, 432/252 freetery Whieh forms the smelting ehamber with a [51] Int. Cl. F27b 3/00 tam: Plate Completely and the smelting Chamber is 58 Field of Search 263/10, 46; 13/31 Seeled against the Outer atmosphere, n further characterized by the fact that the air in the inner space en- [5 References Cited 1 closed by the metallic plate is substituted by inert gas.
  • the present invention relates to a plasma smelting furnace for melting metals by utilizing a plasma jet as the heat source, whereby the plasma gas atmosphere in the furnace is prevented from being contaminated.
  • the pressure in the furnace as a whole becomes higher than the atmospheric pressure by 5 to 30 mm Hg.
  • the pressure in the furnace is as a whole higher than the atmospheric pressure to a certain extent, and where more than two locations for communicating the inside of the furnace with the open air are provided, the current of gas from those locations can cause introduction of atmospheric air.
  • the plasma gas is supplied into the furnace through a plasma torch and the used plasma gas namely waste gas is exhausted through an exhaust orifice formed through the furnace proper or the furnace cover or through the gaps for exhaust formed in the circumference of the plasma torch which penetrates the furnace cover. Accordingly, in case the gas passages communicating the inside of the furnace with the open air other than these openings for exhaust are not sealed, it is very difficult to assure the effect of the plasma smelting by preventing the contamination of the atmosphere in the furnace.
  • the refractory which lines the furnace proper is generally a porous material so that it is not only incapable of forming a sealed wall for shielding the inside of the furnace completely from the open air but also tends to produce cracks on the refractory lining due to repetition of the expansion and contraction caused by the heating and cooling of the furnace even if it originally had a degree of sealability. In case such cracks are caused, the sealability of the refractory is lost and the gas leakage through the refractory wall cannot be avoided.
  • the outside of the refractory is covered with the steel sheet, but this covering steel sheet is provided with a plurality of ventilating holes for drying the refractory lining which lines the furnace proper, and thus the function of sealing the furnace is carried out exclusively by the wall of the refractory.
  • the thickness of the refractory of the furnace proper is thinnet, and each portion of the coil or the refractory of the inside of the coil is ordinarily supported by the coil itself, and therefore the sealed wall for shielding the inside of the furnace from the open air is formed by the refractory of the furnace proper.
  • a gas passage exists between the inside of the furnace and the open air.
  • This passage is formed by the pores of the refractory or the cracks caused on the refractory lining except the exhaust opening for the discharging of the waste gas, whereby open air enters the inside of the furnace by the gas leakage through this passage with the recognized disadvantages that the open air which enters even if it is of relatively small quantity, functions to contaminate the atmosphere of the inside of the furnace, instabilizes the generation of the plasma and reduces the heating effect of the plasma jet.
  • the air is absorbed in the molten metal in the furnace and mixed therein to degrade the quality of the molten metal.
  • the construction of the plasma smelting furnace of the present invention is based on the fact that the refractory which forms the furnace proper is porous and that during the use of the furnace, many cracks occur in the refractory lining. Therefore the whole of the furnace proper is covered completely with a metallic plate such as steel sheet and the inside of the furnace is completely sealed against the open air except the exhaust opening for discharging the waste gas. Thus the gas passage existing in the refractory lining which forms the furnace proper is completely shut off from the open air, and accordingly the atmosphere in the furnace is effectively prevented from being contaminated by entering of open air. Because of the above effective prevention, the desired effect by the plasma smelting, namely, the effective and rapid heating and maintenance of quality of the molten metal can be positively achieved.
  • the covering the whole of the furnace proper by a metal sheet in accordance with the present invention can be carried out by utilizing a covering steel sheet which is generally used in the conventional plasma smelting furnace for the purpose of supporting and protecting the refractory which forms the furnace proper.
  • a plurality of ventilating holes can be formed on the covering steel sheet for drying the refractory lining and therefore after the furnace is constructed and the refractory lining is sufficiently dried, a suitable cover can be mounted on the ventilating holes so that the metal wall is completely sealed by means of the covering steel sheet.
  • a suitable inert gas such as argon
  • the air in the space between the metal sheet and refractory is replaced with the inert gas, the air from the smelting chamber is discharged and the plasma gas is filled and the plasma jet is generated, there is no cause for concern that the atmosphere in the furnace is contaminated by entrance of the air.
  • a suitable inert gas such as argon
  • FIG. 1 of the accompanied drawings is a sectional elevational view illustrating the metal smelting furnace of the present invention in which the plasma jet is used as the heat source;
  • FIG. 2 is a sectional elevation showing the embodiment in which the present invention is applied to a metal smelting furnace that employs heating by a plasma jet and induction electric heating and stirring.
  • the plasma smelting furnace of the present invention as shown in FIG. 1 is formed in such a way that the circumferential side of the refractory 2 forming the crusible type smelting chamber 1 of the furnace and the total exterior surface of the bottom portion are completely covered by the covering steel sheet 3 and the top portion of the furnace is covered by the furnace cover made of steel sheet which is lined with a change refractory lining 4 and a hole 6 is formed in the furnace cover 5 and the central portion of the lined refractory lining 4.
  • the hole 6 is formed as a through hole to permit the formation of an annular gap 7 between its exterior circumferential wall and the inner wall of the hole whereby the tip portion of the plasma torch 8 inserted in the furnace is positioned at the top portion of the smelting chamber 1.
  • the furnace bottom electrode 9 At the bottom portion of the smelting chamber 1 is the furnace bottom electrode 9. At its outer end portion, the covering steel sheet 3 is penetrated and led to the outside by means of a suitable airtight insulating insulator 10.
  • the joint between the covering steel sheet 3 and the furnace cover 5 is provided with the sand seal 11 to couple and seal the joint in an airtight manner, and if desired, a suitable number of ventilating holes 12 are bored in the covering steel sheet 3 and sealed by means of suitable detachable closing cover 13 as occasion demands the closing cover 13 is removed to effect the ventilation for drying the refractory, and also the operation of replacing the air existing between the refractory 2 and the covering steel sheet 3 with a suitable inert gas.
  • the plasma gas is continuously fed into the furnace from the air feeding tube 14, and the plasma gas in the smelting chamber 1 which has been used is discharged outside of the furnace through the annular gap 7, but the smelting chamber 1 is completely sealed from the open air except for the exhaust opening formed by the annular gap 7.
  • the refractory 2 or the refractory lining 4 is of porous material, or the cracks are caused thereon, there is no cause for concern that the atmosphere in the furnace is contaminated as air or other undesired gas cannot enter, thus the desired plasma effect can be extremely effectively achieved.
  • the plasma smelting furnace of the present invention as shown in FIG. 2 is such that induction electric heating and stirring are jointly employed in the plasma smelting furnace which is shown in FIG. 1, with similar reference numerals being used for similar parts.
  • a tubular port 20 for ventilation is formed separate from the ventilating hole 12 for drying the refractory and the port 20 is closed by the closing plug 21.
  • the operation of the plasma smelting furnace as shown in FIG. 2 is such that the plasma jet which is generated by the plasma torch 8 is jetted to the material 15 to effect the heating of the material 15 and at the same time a suitable frequency alternating current is caused to flow to the annular coil 16 by a conventional method.
  • the material is heated by the function of the induction current which is produced in the material and agitated but other operations are similar to those of the plasma smelting furnace as shown in FIG. 1.
  • the plasma smelting furnace of the present invention not only when the furnace is new or the at the initial period of the replacement of the lining, but also even after the cracks are formed on the refractory due to the frequent use of the furnace, entering of air into the furnace from the outside is completely substantially blocked by the covering metallic sheet which encloses the furnace proper, and the mixing of the oxygen in the atmosphere in the furnace is confirmed to be dropped to less than 0.01 percent.
  • Table 1 shows the relationship between the sealed condition of the furnace chamber and the mixed quantity of the oxygen in the atmosphere of the furnace chamber and in the molten metal bath.
  • the molten metal bath is a molten steel of high carbon chromium bearing steel (.llSzSOJZ) '
  • the cracks that can be recognized by the naked eye denote cracks of about 0.2-1
  • the plasma smelting furnace of the present invention it is possible to achieve the given effect or advantage of this plasma smelting by a simple construction in which the outside of the refractory which forms the furnace proper is enclosed completely by a metallic sheet and the gas passage between the smelting chamber other than the opening for exhausting waste gas and the open air is completely shut off; furthermore the air between the refractory and the metallic sheet as well as between refractories and/or cracks is replaced by an inert gas whereby its effect and advantage can be remarkably improved.
  • a plasma smelting furnace in which the plasma jet is used as the heat source comprising:
  • b. means to completely enclose the outside of said smelting chamber to preclude the passage of gas between the smelting chamber and the open air except for an opening to exhaust the used plasma gas.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Combustion & Propulsion (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • General Health & Medical Sciences (AREA)
  • Toxicology (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Furnace Details (AREA)
  • Gasification And Melting Of Waste (AREA)
  • Vertical, Hearth, Or Arc Furnaces (AREA)
  • Discharge Heating (AREA)
US00142614A 1970-05-19 1971-05-12 Plasma smelting furnace Expired - Lifetime US3828107A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45042218A JPS5036407B1 (de) 1970-05-19 1970-05-19

Publications (1)

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US3828107A true US3828107A (en) 1974-08-06

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US00142614A Expired - Lifetime US3828107A (en) 1970-05-19 1971-05-12 Plasma smelting furnace

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US (1) US3828107A (de)
JP (1) JPS5036407B1 (de)
BE (1) BE767415A (de)
DE (1) DE2124412C2 (de)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4017672A (en) * 1976-03-11 1977-04-12 Paton Boris E Plasma-arc furnace for remelting metals and alloys
US4101725A (en) * 1976-08-16 1978-07-18 Nikolai Semenovich Shelepov Hearth electrode for melting furnaces
US4493088A (en) * 1981-01-13 1985-01-08 Voest-Alpine Aktiengesellschaft Plasma melting furnace
US4644557A (en) * 1984-08-03 1987-02-17 Skw Trostberg Aktiengesellschaft Process for the production of calcium carbide and a shaft furnace for carrying out the process
US4734551A (en) * 1986-01-10 1988-03-29 Plasma Energy Corporation Method and apparatus for heating molten steel utilizing a plasma arc torch
US4918282A (en) * 1986-01-10 1990-04-17 Plasma Energy Corporation Method and apparatus for heating molten steel utilizing a plasma arc torch
CN1313368C (zh) * 2003-10-10 2007-05-02 曹文兴 一种太阳能电池用硅的生产设备及方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0167037B1 (de) * 1984-07-06 1990-05-30 BBC Brown Boveri AG Badelektrode zu Pfannenofen
FR2660745A1 (fr) * 1990-04-05 1991-10-11 Siderurgie Fse Inst Rech Four electrique muni de moyens d'etancheite perfectionnes.

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2916535A (en) * 1948-05-01 1959-12-08 Westinghouse Electric Corp Ultra-high-temperature furnace
US3495019A (en) * 1968-06-12 1970-02-10 Briggs & Stratton Corp Induction furnace for melting aluminum and similar metals
US3619840A (en) * 1969-07-10 1971-11-16 Optical Coating Laboratory Inc Electron beam evaporation source

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3429564A (en) * 1965-08-02 1969-02-25 Titanium Metals Corp Melting furnace

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2916535A (en) * 1948-05-01 1959-12-08 Westinghouse Electric Corp Ultra-high-temperature furnace
US3495019A (en) * 1968-06-12 1970-02-10 Briggs & Stratton Corp Induction furnace for melting aluminum and similar metals
US3619840A (en) * 1969-07-10 1971-11-16 Optical Coating Laboratory Inc Electron beam evaporation source

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4017672A (en) * 1976-03-11 1977-04-12 Paton Boris E Plasma-arc furnace for remelting metals and alloys
US4101725A (en) * 1976-08-16 1978-07-18 Nikolai Semenovich Shelepov Hearth electrode for melting furnaces
US4493088A (en) * 1981-01-13 1985-01-08 Voest-Alpine Aktiengesellschaft Plasma melting furnace
US4644557A (en) * 1984-08-03 1987-02-17 Skw Trostberg Aktiengesellschaft Process for the production of calcium carbide and a shaft furnace for carrying out the process
US4734551A (en) * 1986-01-10 1988-03-29 Plasma Energy Corporation Method and apparatus for heating molten steel utilizing a plasma arc torch
US4918282A (en) * 1986-01-10 1990-04-17 Plasma Energy Corporation Method and apparatus for heating molten steel utilizing a plasma arc torch
CN1313368C (zh) * 2003-10-10 2007-05-02 曹文兴 一种太阳能电池用硅的生产设备及方法

Also Published As

Publication number Publication date
JPS5036407B1 (de) 1975-11-25
DE2124412C2 (de) 1985-06-27
BE767415A (fr) 1971-10-18
DE2124412A1 (de) 1971-12-02

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