Classifications

• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/40—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by heating to effect chemical change, e.g. pyrolysis
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D1/00—Fire-extinguishing compositions; Use of chemical substances in extinguishing fires
  • A62D1/0028—Liquid extinguishing substances
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D3/00—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances
  • A62D3/10—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation
  • A62D3/19—Processes for making harmful chemical substances harmless or less harmful, by effecting a chemical change in the substances by subjecting to electric or wave energy or particle or ionizing radiation to plasma
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B19/00—Heating of coke ovens by electrical means
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B39/00—Cooling or quenching coke
  • C10B39/04—Wet quenching
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10B—DESTRUCTIVE DISTILLATION OF CARBONACEOUS MATERIALS FOR PRODUCTION OF GAS, COKE, TAR, OR SIMILAR MATERIALS
  • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/22—Organic substances containing halogen
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2101/00—Harmful chemical substances made harmless, or less harmful, by effecting chemical change
  • A62D2101/20—Organic substances
  • A62D2101/28—Organic substances containing oxygen, sulfur, selenium or tellurium, i.e. chalcogen
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
  • A62D2203/04—Combined processes involving two or more non-distinct steps covered by groups A62D3/10 - A62D3/40
• • A—HUMAN NECESSITIES
  • A62—LIFE-SAVING; FIRE-FIGHTING
  • A62D—CHEMICAL MEANS FOR EXTINGUISHING FIRES OR FOR COMBATING OR PROTECTING AGAINST HARMFUL CHEMICAL AGENTS; CHEMICAL MATERIALS FOR USE IN BREATHING APPARATUS
  • A62D2203/00—Aspects of processes for making harmful chemical substances harmless, or less harmful, by effecting chemical change in the substances
  • A62D2203/10—Apparatus specially adapted for treating harmful chemical agents; Details thereof

Definitions

• This invention relates to material processing such as the destruction of toxic waste matter, and is concerned with both a process and apparatus. It will be convenient to hereinafter particularly describe the invention with reference to the example application to destruction of waste matter.
• This invention relates particularly but not exclusively to treatment of waste products resulting from chemical treatment, chemical conversion and the like.
• These products often contain highly toxic directly physiologically active or carcinogenic substances.
• such products can include per- or poly- chlorinated and per- or polyfluorinated aliphatic or aromatic substances such as chlorophenols, dioxins and furans. In addition to their toxicity, these compounds often exhibit high chemical and thermal resistance.
• Waste matter destruction is becoming a problem of great magnitude throughout the world.
• Two methods of removing contaminated material have become established, namely land fill and high temperature combustion techniques.
• the toxic matter In the land fill technique, which generally only applies to solids, the toxic matter is not destroyed, but is simply stored in dumps. At best the dumps are designed to prevent contamination of ground water by waste matter deposited therein. This technique is not suited to some areas, for example, areas in which there is an ongoing danger of leakage, seepage or the like.
• the high temperature combustion technique the generally attainable temperatures, for example up to 1500 C, are insufficient to destroy all the toxic substances. The most thermally stable harmful substances are thus delivered into the atmosphere. Further the combustion process can promote the formation of additional dioxins and furans which are then also delivered into the atmosphere.
• a process for material processing according to the invention is characterised in that a body of material is introduced into a pyrolyser and is subjected to high temperature for a period of time sufficient to achieve substantially complete pyrolysis, after which the material leaves the pyrolyser and is then subjected to rapid quenching.
• the quenched material is subjected to an environment in which residual toxic compounds are adsorbed on a solid carrier substance so as to be thereby capable of separation from the main body of the material.
• the solid carrier substance referred to above is particulate carbon, and it is further preferred that the carbon is formed by the treatment of the waste material in the pyrolyser.
• the material to be treated may be in the form of a liquid which is atomised on introduction to the pyrolyser.
• the material may be in a particulate solid form or in the form of a gas.
• the pyrolyser includes a high energy electrothermal plasma into which the atomised material is injected so as to result in dissociation of the molecules of which the material is composed. The speed at which such dissociation occurs is governed, at least in part, by the temperature of the plasma. It is further preferred that the material emerges from the plasma arc as a stream which passes through a hot zone within which the temperature of the material is maintained at a sufficiently high level to encourage continuation of the pyrolysis which is commenced within the plasma.
• Residence time within the hot zone may be determined as appropriate to increase the probability that there is complete dissociation of all molecules within the material stream.
• the material stream is cooled by being subjected to rapid quenching in a cooling zone after leaving the hot zone, and the speed of quenching is preferably such as to prevent, or at least minimise, recombination of the dissociated ions.
• Residual toxic compounds which are separated from the material stream by absorption on particulate carbon as previously described may be destroyed by subjecting the particulate carbon to appropriate further treatment.
• the aforementioned hot zone is defined by a tube (hereinafter called the flight tube) through which the material stream travels between the plasma arc and the cooling zone.
• the material stream preferably enters that tube immediately upon emerging from the plasma arc.
• the dimensions and construction of the flight tube can have an influence on the efficiency of the process as hereinafter discussed.
• the pyrolysis of material such as waste material may result in production of carbon particles as soot or activated carbon, and those particles could influence downstream processing of the material.
• the particles could block or partially block the flight tube. This will especially be the case where the material to be treated comprises mainly hydrocarbons.
• the material comprises mainly oxygen containing organic compounds, there may not be a problem with excessive carbon particles.
• oxygen is introduced into the plasma so as to react with carbon particles as may be formed, and thereby produce gaseous carbon compounds with the concomitant evolution of heat.
• Such addition of oxygen may therefore lower the level of solid carbon within the material stream so as to more easily facilitate downstream processing of that material for example, facilitate passage of the material stream through the flight tube.
• the liberated heat assists in maintaining the temperature of the material stream suitably high as it passes through the flight tube to resist recombination to form toxic compounds.
• the need to convert solid carbon to gaseous carbon compounds by addition of oxygen to the process material may be eliminated, or at least reduced, by the dilution of the material to be processed in an inert carrier liquid which passes through the apparatus without affecting the reaction dynamics.
• the carrier liquid will have the effect of lowering the percentage by weight of carbon particles in the stream issuing from the plasma.
• the amount of inert carrier liquid added will be controlled to reduce the percentage by weight of carbon particles to a level that avoids blockages of equipment without the addition of any oxygen.
• the level of carbon particles in the material stream issuing from the flight tube may be such as to cause blocking or partially blocking at the cooling zone and/or at some other part of the apparatus following the cooling zone, and that may occur notwithstanding the introduction of oxygen into the plasma as described above.
• further oxygen is added to the stream issuing from the flight tube so as to react with the carbon particles and lower the level of particles within the material stream.
• the reaction of the oxygen with the carbon is exothermic which assists in maintaining the temperature of the material stream suitably high until actual quenching of the stream takes place.
• the high temperatures tend to resist recombination of ions to form toxic compounds. It is preferred that a sharp temperature gradient be effectively provided at the cooling zone.
• the cooled material may be exposed to an alkaline environment for encouraging the adsorption of any acidic residual toxic compounds on the carrier substance, for example carbon particles.
• toxic compounds which escape pyrolysis, or which are formed by recombination following pyrolysis can be isolated on the carbon particles, and those particles may be separated from the remainder of the processed material by any suitable means. By way of example, that separation may be achieved through filtration.
• the separated carbon particles, with toxic compounds adsorbed thereon, may be subjected to further treatment to decompose the toxic compounds.
• the particles may be subjected to further treatment which leads to the toxic compounds being desorbed into a liquid which is then recirculated through the process.
• the carbon particles may be disposed of by landfill.
• the procedure adopted in any circumstance will generally depend on the level of toxic compounds on the carbon particles.
• material treatment apparatus including, a pyrolyser comprising means for generating a plasma arc and means for containing plasma beyond the region of said arc, means for introducing material into said pyrolyser as a fine spray and/or as a gas, said material introducing means being located at or adjacent the region of said arc, said pyrolyser having a material exit end, and quenching means located at or adjacent said exit end.
• Figure 1 is a flow diagram representing one form of the process according to the invention.
• Figure 2 is a diagrammatic sectional view through one form of pyrolyser for use in a process as represented by Figure 1.
• Figure 3 is a semi-diagrammatic cross-sectional view of one form of flight tube suitable for use in the apparatus shown by Figure 2.
• Figure 4 is a semi-daigrammatic cross-sectional view of another form of flight tube suitable for use in the apparatus of Figure 2.
• Figure 5 is a diagrammatic view of apparatus in accordance with one embodiment of the invention.
• the line 1 represents the path of the material to be treated as it is introduced into the pyrolyser 2.
• the material may be introduced into the pyrolyser 2 in any suitable form, but it is preferred that it be in the form of a fine spray of liquid and/or solid particles, or a gas, or a combination of such a fine spray and a gas. It is further preferred that the material be injected into the pyrolyser 2 under pressure.
• the stream of liquid may be atomised at or immediately preceding the point of injection into the pyrolyser 2 , and any suitable nozzle or other means may be used for that purpose.
• the liquid droplets resulting from the atomisation have a diameter of 100 microns or less.
• the liquid droplets need to be sufficiently small to enable complete pyrolysis. If they are too large, the surface of the droplets may merely char under the conditions existing within the pyrolyser 2.
• each of those particles is preferably of a suitably small size for the reason given above.
• a particle size of 100 microns or less will generally be satisfactory.
• the pyrolyser 2 includes means 3 for generating a plasma arc 4 so as to enable production of a high energy electrothermal plasma.
• the pyrolyser 2 also includes a hot zone 6 immediately following the arc generating means
• the plasma gas 7 is argon or an argon mixture as that produces an inert plasma atmosphere in which the pyrolysis takes place.
• the arc generating means 3 may, for example, be a plasma torch the same as or similar to that disclosed by PCT Patent Application
• the temperature within the plasma may typically be in the region 10,000°C to 15,000°C.
• other types of plasma such as a steam plasma may also be used.
• the direction in which the material to be treated is introduced into the plasma arc 4 may be selected according to preference or circumstances.
• the direction may be generally parallel to the line of the arc 4, or generally transverse thereto, but the later is usually preferred.
• the region of the pyrolyser 2 at which the material to be treated is introduced into the plasma is maintained at a suitably high temperature, for example, a temperature of 1,000°C or preferably higher.
• the material may be injected directly into the core of the plasma arc 4, or at least close to the downstream attachment 8 of the arc 4. If direct injection is not possible, the surfaces of the torch 3 in the region of material introduction may be heated to maintain a temperature of a suitably high level.
• FIG 2 provides a clearer indication of the preferred location of the point 9 at which material to be treated is introduced into the pyrolyser 2.
• the particular torch 3 which is shown in Figure 2 , and which forms part of the pyrolyser 2, includes a cathode 10 and two anodes 11 and 12 separated by a bank 13 of spacers.
• the anode 11 functions as a start-up anode for initiating the arc 4, and once generated the arc 4 is then extended so that its downstream attachment 8 is at the anode 12.
• Other forms of torches could be adopted.
• material to be treated is injected into the torch passage 14 at or adjacent the location of the arc attachment 8.
• the direction of that injection is generally transverse to the longitudinal axis of the passage 14 as that facilitates injection into the core of the arc 4.
• the molecules which make-up the injected material are caused to dissociate under the influence of the high temperatures prevailing within the plasma, and the material thereby undergoes pyrolysis, or at least substantial pyrolysis.
• the material emerges from the plasma arc 4 as a stream 5 which is directed into and through the hot zone 6.
• the stream of material 5 is primarily a gas having associated therewith particles of solid carbon in the form of soot.
• the hot zone 6 is formed by an elongate hollow tube which will be hereinafter referred to as the flight tube.
• the tube 6 in effect forms an extension or continuation of the torch passage 14, and the dimensions of the tube 6 will be selected to suit particular requirements and circumstances.
• the tube 6 It is a basic function of the tube 6 to provide containment of the material stream 5 in an environment which promotes continuation of the pyrolysis process. That is, it may happen that pyrolysis of the material is not completed within the torch 3, and the function of the tube 6 is to provide an extension of the environment within which pyrolysis takes place. In particular, the tube 6 extends the residence time of the material within an appropriate high temperature environment and thereby optimises the possibility that complete pyrolysis will be achieved.
• the flight tube is slender and has a diameter to length ratio of about 2 in 25.
• the length of the tube may be selected so as to achieve a suitable residence time of the processed material within the tube and any suitable diameter to length ratio may be adopted. The nature of the toxic compounds within the material to be treated will -9- influence the determination of an appropriate residence time within the tube 6.
• the temperature of the stream 5 entering the tube 6 may be above 3,500 C and the temperature of the stream exiting the tube 6 may be 1,200°C, or thereabouts.
• the fluid flow boundary layer of the material stream which contacts the surrounding surface of the tube 6 will tend to cool because of ' that contact.
• the tube 6 may be designed in such a way as to enable control of the boundary layer so that it is kept as thin as possible.
• it is desirable that the temperature of the material stream is substantially consistent throughout that stream as it emerges from the exit end 15 of the pyrolyser 2.
• Figure 3 The inner surface of the flight tube 6 shown in Figure 3 is provided with a series of lips 16 which tend to deflect the boundary layer of the material stream 5 back towards the axial center of that stream.
• the resulting turbulence inhibits the formation of a distinct cool boundary layer, and there is continual mixing of the boundary layer with the inner relatively hot body of the material stream such that a substantially consistent temperature is maintained across the width of the stream.
• Figure 4 illustrates another approach in which the tube 6 has a lining 17 which is capable of withstanding high temperatures, and particularly temperatures above 1,000°C.
• the lining 17 may be composed of a ceramic material. If desired, such an arrangement may be modified by introducing an external source of heat to the lining 17 at an appropriate location, such as adjacent to the exit end 15 of the pyrolyser 2.
• the body 18 of the tube 6 which surrounds the lining 17 may be cooled by water (for example) entering at the inlet 19 and exiting at the outlet 20. Similar cooling may be desirable in other forms of the tube 6, including that shown in Figure 3.
• the material stream 5 issuing from the torch 3 will contain carbon particles.
• a stream of oxygen may be fed into the pyrolyser 2 for converting some of the carbon particles to gaseous carbon compounds.
• the oxygen is fed into the torch 3 at a location 21 adjacent the point 9 at which the material to be treated is introduced.
• Other arrangements are clearly possible.
• the tube 6 may include a graphite lining.
• it may be important to control the stream of oxygen entering at 21, so as to maintain an oxygen deficient atmosphere within the tube 6.
• the ratio of oxygen to carbon may be maintained at 30% below stoichiometric levels. If such an atmosphere is not maintained some oxygen may react with the carbon of the tube lining, thereby eating away the lining.
• the material stream 5 passing out of the exit end 15 of the pyrolyser 2 is subjected to quenching in a cooling zone 22.
• the material is then, and/or subsequently, subjected to an environment as hereinafter described in which residual toxic organic compounds are adsorbed on a particulate carrier.
• the carrier substance may be provided by the unreacted carbon particles remaining within the material stream 5.
• the level of carbon particles in the material stream 5 passing out of the exit end 15 may, for example, be 1% by weight, or greater. Such a level of carbon may cause clogging or blocking of components of the processing apparatus which follow the pyrolyser 2.
• the carbon content of the material stream entering the cooling zone 22 is in the order of 0.5% by weight.
• the introduction of the further oxygen stream 23 may have another effect. That is, the heat generated by the reaction of that oxygen with carbon may assist in maintaining the material stream 5 at a suitably high temperature right up until actual quenching takes place.
• the temperature of the material stream 5 just prior to quenching be at least 1,500 C, and it is preferred that the temperature be in order of 1,800°C to 2,000°C.
• the higher temperatures resist recombination of dissociated ions to form toxic compounds, for example dioxins.
• the cooling zone 22 includes a bank of sprays 24 arranged to produce a cool barrier 25 through which the material stream 5 must pass. That is, the stream 5 is confined to a passage 26 which is completely filled at the location of the sprays 24 by the barrier 25.
• the arrangement is such that quenching of the material stream is complete, and that as a result there is a very sudden sharp drop in the temperature of the material.
• the passage 26 is formed as an extension of the passage through the tube 6.
• the cooled material issuing from the cooling zone 22 may be passed into and through a scrubber 27 as shown.
• the pH of the scrubber 27 will generally be alkaline for removing acidic compounds from the material received.
• the carbon particles within that material may be dispersed within a body 28 of the alkaline scrubber liquor so that acidic organic compounds are encouraged to be adsorbed on the carbon particles.
• the optimum process parameters such as pH and temperature of the scrubber, liquor which are required to achieve maximum toxic organic compound adsorption, may be determined by routine experimentation.
• the scrubber liquor is a sodium hydroxide solution, but other types of liquor may be used.
• the same liquor may be used in the quench sprays 24 and the scrubber sprays 29.
• a pump 30 may operate to draw liquor from the liquor body 28 to feed the sprays 24 and 29.
• the line 31 in Figure 1 represents the supply of liquor to the scrubber 27, and the line 32 represents the withdrawal of spent liquor from the scrubber 27.
• the carbon particles may be separated from the scrubber liquor by means of a simple filtration process, which is indicated in Figure 1 by the block 33. That filtration may be carried out on a continuous basis or on a batch basis.
• the toxic organic compounds adsorbed on the carbon particles may be separated from the carbon particles by a desorption process which is represented by the block 34 in Figure 1. That is, the adsorption process effected in the scrubber 27 is reversed.
• the compounds are typically desorbed in water which can be recycled through the process as part of the material input 1.
• the scrubber 27 has a rectangular configuration and is substantially larger than the tube which forms the cooling zone 22.
• a plurality of scrubber sprays 29 are located in the operatively upper region of the scrubber 27 for directing scrubber liquor as a fine spray or mist. The direction of that spray or mist is preferably downwards.
• the apparatus may include an explosion vent 35 as shown in Figure 5, to vent the system in the event of the build-up of an explosive gaseous mixture. This is an important safety feature to reduce the danger of explosion.
• the explosion vent is of known form and construction.
• the vent 35 is located adjacent the scrubber 27.
• the material which has remained in the gaseous form and which has not been scrubbed from the gas in the scrubber 27, may be passed to atmosphere by way of a stack 36 shown in Figure 5.
• the stack 36 may, for example, include a number of stack sprays 37 which operate to remove any remaining traces of gaseous compounds having an affinity for an aqueous alkaline environment.
• the stack sprays 37 are supplied with liquor by way of the pump 30.
• the pyrolyser 2 specifically, and the entire apparatus more generally, forms a very compact unit which lends itself to on-site use.
• the apparatus can be integrated into an existing process so that there is no nett production of toxic waste. This is a major advantage as the transportation of toxic substances is hazardous.
• a unique characteristic of the process described is the deliberate retention of particulate carbon within the stream of material and the control of the process conditions such that the carbon particles act as a carrier substance for toxic organic compounds which have survived the pyrolysis phase of the process. That is, the organic compounds which survived the processing steps preceding the quenching process, are effectively captured by attachment or adsorption on the carbon particles. The surviving organic compounds are thereby captured in a manner which facilitates convenient disposal or alternatively subsequent processing as considered appropriate, depending on the level of toxic organic compounds. That is contrary to the accepted practice of inhibiting carbon formation in existing toxic compound destruction processes.
• a process according to the invention is useful for the effective destruction of a wide variety of toxic products, including chlorophenols and dioxins. The process is robust and safe.

Landscapes

• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• General Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Business, Economics & Management (AREA)
• Emergency Management (AREA)
• Materials Engineering (AREA)
• Organic Chemistry (AREA)
• Health & Medical Sciences (AREA)
• Toxicology (AREA)
• General Health & Medical Sciences (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Treating Waste Gases (AREA)
• Processing Of Solid Wastes (AREA)
• Chemical Or Physical Treatment Of Fibers (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Electrical Discharge Machining, Electrochemical Machining, And Combined Machining (AREA)
• Developing Agents For Electrophotography (AREA)
• Gasification And Melting Of Waste (AREA)

Applications Claiming Priority (4)

Publications (3)

Family

ID=3776019

Family Applications (1)

Country Status (8)

Families Citing this family (15)

Citations (1)

Family Cites Families (8)

• 1993
  • 1993-03-04 AT AT93905105T patent/ATE195261T1/de not_active IP Right Cessation
  • 1993-03-04 WO PCT/AU1993/000089 patent/WO1993017759A1/en active IP Right Grant
  • 1993-03-04 PT PT93905105T patent/PT629138E/pt unknown
  • 1993-03-04 EP EP93905105A patent/EP0629138B1/de not_active Expired - Lifetime
  • 1993-03-04 DE DE69329189T patent/DE69329189T2/de not_active Expired - Lifetime
  • 1993-03-04 CN CN93103682A patent/CN1036635C/zh not_active Expired - Fee Related
  • 1993-03-04 ES ES93905105T patent/ES2149199T3/es not_active Expired - Lifetime
• 2000
  • 2000-11-09 GR GR20000402490T patent/GR3034802T3/el unknown

Patent Citations (1)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events