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WO1997014528A1 - Procede plasmalytique d'elimination des dechets - Google Patents

Procede plasmalytique d'elimination des dechets Download PDF

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Publication number
WO1997014528A1
WO1997014528A1 PCT/US1995/013317 US9513317W WO9714528A1 WO 1997014528 A1 WO1997014528 A1 WO 1997014528A1 US 9513317 W US9513317 W US 9513317W WO 9714528 A1 WO9714528 A1 WO 9714528A1
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WO
WIPO (PCT)
Prior art keywords
electrode
matter
particulate
zone
waste
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.)
Ceased
Application number
PCT/US1995/013317
Other languages
English (en)
Inventor
Jozef K. Tylko
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.)
Refranco Corp
Original Assignee
Refranco Corp
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
Priority claimed from US08/109,606 external-priority patent/US5403991A/en
Priority to US08/109,606 priority Critical patent/US5403991A/en
Priority to US08/249,153 priority patent/US5626249A/en
Priority to EP94925857A priority patent/EP0722376A4/fr
Priority to JP50708994A priority patent/JPH09501794A/ja
Priority to PCT/US1994/009146 priority patent/WO1995005263A1/fr
Priority to ZA946162A priority patent/ZA946162B/xx
Priority to CN94109323A priority patent/CN1103232A/zh
Priority to US08/521,275 priority patent/US5605640A/en
Priority to PCT/US1995/013317 priority patent/WO1997014528A1/fr
Application filed by Refranco Corp filed Critical Refranco Corp
Publication of WO1997014528A1 publication Critical patent/WO1997014528A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32055—Arc discharge
    • 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
    • C10B53/00—Destructive distillation, specially adapted for particular solid raw materials or solid raw materials in special form
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22B—PRODUCTION AND REFINING OF METALS; PRETREATMENT OF RAW MATERIALS
    • C22B4/00—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys
    • C22B4/005—Electrothermal treatment of ores or metallurgical products for obtaining metals or alloys using plasma jets
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
    • H01J37/32—Gas-filled discharge tubes
    • H01J37/32009—Arrangements for generation of plasma specially adapted for examination or treatment of objects, e.g. plasma sources
    • H01J37/32055—Arc discharge
    • H01J37/32064—Circuits specially adapted for controlling the arc discharge
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05H—PLASMA TECHNIQUE; PRODUCTION OF ACCELERATED ELECTRICALLY-CHARGED PARTICLES OR OF NEUTRONS; PRODUCTION OR ACCELERATION OF NEUTRAL MOLECULAR OR ATOMIC BEAMS
    • H05H1/00—Generating plasma; Handling plasma
    • H05H1/24—Generating plasma
    • H05H1/26—Plasma torches
    • H05H1/32—Plasma torches using an arc
    • H05H1/44—Plasma torches using an arc using more than one torch
    • 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
    • Y02P10/20—Recycling

Definitions

  • the present invention relates generally to the treatment of matter by interaction with plasma and, in particular, to a method for the treatment of waste material via discrete electrical discharges.
  • the industrial application of low temperature plasma technology has developed along two different routes.
  • the first route in which the volume of the arc discharge was not used for entrainment of feed stocks
  • the second route aims at the treatment of particles in the whole volume of the plasma—treatment "in flight.” For this purpose, it was required to expand the plasma and this involves increasing its original volume. This is the development of Jozef K. Tylko, the inventor herein.
  • the method of the incorporated patent addressed many of the limitations of the orbiting torch technology discussed above.
  • an arc discharge was generated between stationary electrode structures, at least one of those structures being annular.
  • a primary requirement of the system was the establishment and maintenance of an expanded plasma within the reaction zone between the electrode structures.
  • Early versions of the methodology of the incorporated patent also required utilization of a plasmatron. Later versions utilized a simple electrode structure as the central cathode while maintaining an annular ring structure for the anode, the annular anode being formed by multiple anode segments.
  • the method of the incorporated patent resolved the mechanical limitations in the prior art by orbiting the arc by non-mechanical means whereby rapid rates of "rotation" far greater than those possible by mechanical means were attained. Additionally, pulsation of the arc by rapid changes in the applied power established conditions which improved the ability to maintain the arc discharge while also utilizing non-thermal phenomena which enhance the plasma action on the matter being treated.
  • the perceived need to maintain the arc discharge orbiting around the annular electrode structure significantly limited the industrial utility of the method.
  • significant loading volumes remained a problem. During operation, a pattern of least energy configuration was established . As a result, particles were not uniformly treated.
  • the present invention provides the advantages of the method of the incorporated patent while dispensing with the need to maintain an orbiting arc discharge. Instead, a series of discrete electrical discharges are utilized in a treatment or reaction zone defined by spaced electrode structures, the treatment zone containing large amounts of particles to be treated and the discharges acting on these particles "in flight.” As described herein, these discharges may be sequential in time, but need not be sequential in space and may overlap in time and space and may be simultaneous. Thus, the criticality of maintaining a sequential orbiting discharge is eliminated.
  • the reactor is provided with spaced electrode structures defining a treatment zone.
  • the treatment zone is preionized in any desired manner and discrete electrical discharges are produced throughout the treatment zone.
  • the discrete electrical discharges are produced in a desired sequence and in a time interval less than, and preferably considerably less than, the transit time of the matter to be treated through the treatment zone.
  • one or more of the electrode structures may alternatively function as anode or cathode. That is, in accordance with the present invention, the electrode structures may operate with a variable polarity. While this variable polarity, in itself, is an important feature of a reactor which may be utilized to practice the present invention, it also highlights an essential difference between the present invention and the prior art. That is, an electrode utilized in the described prior art devices for the establishment and maintenance of an expanded plasma within the inter-electrode space must maintain its polarity for maintenance of the expanded plasma.
  • the present invention provides a method for the treatment of waste matter by electrical discharge including the steps of positioning the plurality of electrode structures to define a desired inter-electrode space or spaces, conditioning the inter-electrode space as by preionizing that space in any desired manner and establishing an atmosphere free of reactants, introducing particulate matter to be treated to the inter-electrode space and producing a plurality of discrete electrical discharges in a desired sequence between said electrode structures.
  • substantially the entire inter- electrode space is subjected to discrete electrical discharges within a time interval less than the expected residence time of a particle to be treated within the inter- electrode space. Accordingly, waste matter is pyrolyzed by plasma action within the inter-electrode space.
  • a conical treatment zone is established by a central cathode and a plurality of circularly disposed anodes longitudinally displaced from the central cathode. While superficially similar to the disclosed embodiment in the incorporated patent, the structure may be differentiated. In particular, an arc discharge need not "orbit" about an annular anode electrode structure. Instead, in accordance with the present invention, a series of discrete electric discharges may sequentially move along circularly disposed anode structures. Additionally, any or all of such circularly disposed electrode structures may function as a cathode—clearly differentiating the present invention from that of the incorporated patent. Any number of distinct electrode configurations may be employed in accordance with the particular application.
  • the reactor described above may be utilized in the disposal of wastes (solid, liquid, or gaseous, or combinations thereof).
  • particulate waste is subjected to plasma action such that the waste matter is pyrolyzed by plasma action—that is, the waste matter is "plasmalyzed.
  • the reactor may be operated over a wide range of pressures (from below to above atmospheric pressure) and may incorporate a variety of regimes (reducing, oxidizing or neutral) to satisfy the operating requirements specified herein
  • FIG. 1 is a schematic elevational view of a reactor used in accordance with the present invention
  • FIG. 2 is a schematic illustration of a preferred electrode configuration in accordance with the present invention and their control;
  • FIG. 3 is a schematic diagram showing a preferred control circuit in accordance with the present invention.
  • FIG. 4 is a schematic diagram illustrating a modification to a portion of the circuit of FIG. 3;
  • FIGS. 5A-5F are schematic diagrams illustrating a sequence of discrete electrical discharges throughout a treatment zone defined by spaced electrode structures;
  • FIG. 6 is a table showing the on/off states of the power switches of FIG. 3 during part of an operating sequence.
  • FIG. 1 is a diagrammatic illustration of a reactor which may be utilized in the practice of the present invention which incorporates many elements know to the prior art.
  • feedstock dispensers 10 are connected through electrostatic charging probes 11 to a modular head 12 which also receives gas for forming a plasma, coolant, and electrical supplies for the start-up electrode.
  • the introduction of plasma forming gas is represented by arrow 12' .
  • Downstream of the plasma head 12 is a reaction chamber 13 and electrode assembly section 14.
  • the remaining portions of the reactor FIG. 1 are application specific.
  • a reactor to be used for energy recovery may have a combustion chamber 15 immediately below the electrode section 14 with controlled quantities of air injected, at 16, for example, to cause combustion of carbon value separated in the reactor chamber 13.
  • a side duct 17 carries the resulting hot gases away for steam raising and electricity generation while the solid residues pass through a cooling chamber 18 to a collector 19.
  • the reactor illustrated in FIG. 1 is, in the general terms described, similar to that illustrated in FIG. 3 of the incorporated patent.
  • FIG. 2 there is shown an axial electrode structure 20 as may be contained in the modular head 12 of the reactor of FIG. 1 and a plurality of electrode structures 21-26 which may be circularly arranged about the longitudinal center axis of the electrode assembly section 14 of the reactor of FIG. 1.
  • FIG. 2 there is shown an axial electrode structure 20 as may be contained in the modular head 12 of the reactor of FIG. 1 and a plurality of electrode structures 21-26 which may be circularly arranged about the longitudinal center axis of the electrode assembly section 14 of the reactor of FIG. 1.
  • electrode structures 21-26 which, in accordance with the present invention, may be simple rod shaped structures, graphitic or metallic, for example, to which a series of pulse charges are applied as described hereinafter.
  • the electrode 20 may be a simple rod structure similar to the electrodes 21-26.
  • Each of the electrodes 20-26 is connected to a base current source 27 and a pulse current source 28 by associated switches 30 controlled via Switch Control 29.
  • Preferred implementations of the switches 30 are discussed below with reference to FIGS. 3 and 4 and include control terminals, (represented by the terminal(s) 31 in FIG.
  • terminal(s) 31 may represent one or more control terminals as needed by a particular implementation. This is represented herein by the designation "terminal(s) " .
  • Terminal(s) 31 of Switch Control 29 are connected to the terminal(s) 31 associated with switches 30. Those connections are not shown for the sake of clarity but are within the skill of one ordinarily skilled in the art.
  • the central electrode 20 of FIG. 3 is axially arranged with regard to the electrodes 21-26 with the configuration of the electrodes 20-26 defining a treatment or reaction zone which coincides approximately with the inter- electrode space.
  • the electrodes 20-26, and particularly the electrodes 21-26 may be arranged in any desired configuration or arrangement to define or establish any desired inter-electrode space (or any treatment/reaction zone) between themselves or between themselves and the electrode 20.
  • the electrode 20 may be referred to as a cathode while the electrodes 21-26 may function as anodes or, selectively as cathodes, as described below.
  • each electrode may function, selectively, as anode or cathode.
  • each electrode may function, selectively, as anode or cathode.
  • six electrodes 21-26 are shown, any number of electrodes similarly constructed and electrically connected may be provided in accordance with the desired application.
  • Those electrodes connected to function selectively as anode or cathode are sometimes referred to herein as variable polarity electrodes.
  • the switch 30 associated with electrode structure 20 is controlled, via its associated terminal(s) 31 and Switch Control 29, to connect the negative terminal of Base Current Source 27 to the electrode structure 20.
  • one or more of the switches 30 associated with electrode structures 21-26 are selectively controlled, via their associated control terminal(s) 31 and Switch Control 29, to connect the positive terminal of Base Current Source 29 to the selected ones of the electrode structures 21-26.
  • the output of Base Current Source 29 is selected and controlled, in known manner, to establish a base current and thereby preionize the inter-electrode space.
  • This conditioning permits electrical discharges between selected electrode structures with practical potential differences. Such discharges are provided by selective application of pulses from Pulse Current Source 28 across the electrode structures 20-26 in a manner described more fully below. As will be apparent to those familiar with the art, sequential discharges between electrodes 20-26 will "condition" the inter-electrode space by maintaining an ionization level and may permit the base current to be discontinued during continued operation.
  • any of the electrode structures 20-26 may function as a cathode with regard to the electrical discharges.
  • selective control of the switches 30 allows the control of electrical discharges such that those discharges extend throughout the inter-electrode space. This i ⁇ described with reference to FIG. 5.
  • plasma action results in pyrolysis of the matter being treated, pyrolysis by plasma action being described herein as "plasmalysis.
  • FIG. 3 illustrates a preferred control circuit, and in particular, a preferred implementation of the switches 30 of FIG. 2.
  • the switches 30 are formed by one or more gate turn-off thyristors (GTO) .
  • GTO gate turn-off thyristors
  • suitable switching control circuitry represented at 29 is connected to the GTO control electrode, as described above, and as illustrated in FIG. 4 with respect to switch 30, in known manner.
  • the various thyristors are described as being “on” (conducting) or “off” (nonconducting) with control circuitry 29 applying appropriate control signals to the control electrode of the GTO to achieve that state.
  • the switch 30 associated with each of the electrodes 20-26 is formed of three GTOs labeled "C" (for cathode), "P" (for pulse), and "B” (for base current).
  • the positive output of the pulse current source 28 is connected to each of the GTOs labeled "P” while the positive output of base current source 27 is connected to each of the GTOs labeled “B” via magnetically linked inductors 32 which enhance current sharing, as will be understood by those skilled in the art.
  • the switch 30 associated with electrode 20 is controlled such that electrode 20 functions as a cathode. That is, the "C” GTO associated with electrode 20 is conducting and the associated "B” and “P” GTOs are “off”. The “C” GTOs associated with electrodes 21-26 are “off.” Each of the “B” GTOs associated with electrodes 21-26 may be conducting such that current will flow between the "cathode” electrode 20 on one hand, and the "anode” electrodes 21-26 on the other.
  • This current is selected to preionize the inter-electrode space and establish the conditions necessary for an arc discharge between the electrode 20 and the electrodes 21-26 at a practical potential difference.
  • preionization may, alternatively or in addition, be accomplished in any convenient manner.
  • an output from Pulse Current Source 28 will be applied to each of the "P" GTOs associated with electrodes 21-26.
  • one of the GTOs may be rendered “on” resulting in an arc discharge between its associated electrode 21-26 and the cathode electrode 20. It is apparent, that Switch Control 29 may be employed to establish a desired sequence of pulses (between the electrodes 21-26 and electrode 20) as will be described more fully below.
  • Terminals 35 are illustrated in FIGS. 3 and 4 in association with each of the electrodes 20-26.
  • the terminals 35 may be employed in conjunction with a Current Detector 36 to detect the relative current between each or any of the electrodes 20-26 which are functioning as anode.
  • Such current and associated voltage are representative of the loading of the feedstock being treated in the proximity to the relevant electrode. This information can be utilized for selection of firing order or other appropriate action which may depend on the relative loading conditions within the area or field of influence of a particular electrode.
  • the connection between terminal 35 associated with each of the electrodes 20-26 is represented by the terminal 35 associated with Current Detector 36. The specific connections are not illustrated in FIG. 3 for the sake of clarity. Referring now to FIG. 4, there is shown a modification to portions of the embodiment illustrated in FIG.
  • the terminals 43 and 44 may be connected to the negative and positive outputs of a Base Current Source such as that shown at 27 in FIG. 3, with the terminal 43 also being connected to the negative output of a Pulse Current Source such as that shown at 28 in FIG. 3.
  • the terminal 45 in FIG. 4 may be connected to the positive output of a Pulse Current Source such as that shown at 28 in FIG. 3.
  • the electrode 46 may represent any of the electrode structures 20-26 in FIG. 3.
  • the terminal 50 is adapted for connection to the negative output of an additional Pulse Current Source which may correspond in kind to that illustrated at 28 in FIG. 3, while the terminal 51 is adapted for connection to the positive output of that Pulse Current Source.
  • the terminal 50 may also be connected to the negative output of a Base Current Source similar in kind to that illustrated at 27 in FIG. 3, while the negative output of that second Base Current Source is connected to the cathode electrode 20 in a manner which will be apparent to those familiar with the art.
  • a second "C” GTO 52 is provided at terminal 50 while an additional “P” GTO 53 is provided at terminal 51.
  • the GTOs 52 and 53 correspond in function to the GTOs 40 and 41 but are connected to second or additional Pulse Current Sources and Base Current Sources to provide a second set of pulses either as a supplement to the first set of pulses, as by being superimposed with them, or as a set of independent pulses.
  • FIGS. 5A-5F there is diagrammatically illustrated a series of circularly arranged electrodes corresponding to the arrangement of electrode structures 21-26 of FIG. 2.
  • dashed lines extending between the electrode structures 21-26 represent discrete electrical discharges established by the control systems described above, and particularly the control system of FIG 3.
  • each, and any, of the electrodes 21-26 may be selected to function as a cathode with others selectively functioning as anodes.
  • electrode structure 23 is functioning as a cathode while electrode structures 21, 26, and 25 are sequentially functioning as anodes.
  • discrete electrical discharge is first established (via Pulse Current Source 28) between electrode (cathode) 23 and electrodes (anode) 21.
  • the next pulse from Pulse Current Source 28, is applied between electrode 23 as cathode and electrode 26 a ⁇ anode under the control of switch control 29.
  • the next pulse is applied between the electrode 23 as cathode and electrode 25 as anode.
  • the switch control 29 may be operative to select electrode structure 22 as cathode and electrode structures 24-26 as anodes with a series of discrete electrical discharges cycling between those electrodes as represented in FIG. 5B.
  • the sequential firing represented in each of the FIGS. 5A-5F do not exist at the same time although there may be some overlap.
  • the entire volume of the inter-electrode space is subjected to an electrical discharge.
  • particles within that volume are subjected to a treatment in accordance with the present invention.
  • any firing sequence may be employed including multiple discharges generated by multiple pulse and base current sources as described above with reference to FIG. 4.
  • the electrode 20 may be employed (as cathode or anode) within a reactor in accordance with the present invention, while the inter-electrode space may be modified by movement of one or more of electrodes. Indeed, electrode configuration can be easily changed to any desired configuration dependent upon the particular application and the requirements of that application.
  • the electrode configuration and firing sequence and timing are selected such that substantially the entire inter-electrode space is subjected to discrete electrical discharges within a time interval less, and preferably considerably less, than the expected residence time of particles to be treated within the inter-electrode space. This may be accomplished by a selected sequence of discrete electrical discharges in a time interval less, and preferably considerably less, than the transit time of particulate matter to be treated through the reaction zone of the inter-electrode space.
  • the first row indicates the particular electrode structure, while row two indicates the particular "C", "B", and "P” GTOs associated with each electrode.
  • Rows 3-5 of the table represent the first, second, and third pulses delivered by Pulse Current Source 28.
  • An inspection of the table shows that the "C” GTO associated with the electrode 23 is on throughout the three pulses while the "C” GTO associated with the other electrodes is off.
  • the "P” GTO associated with electrode 23 is off, while the "B” GTO associated with the other electrodes are on. This provides a base current via Base Current Source 27 between the cathode of electrode 23 and the other electrodes which serve as anodes.
  • the "P" GTO associated with electrode 21 is conducting (on) thereby applying a potential between the electrode structures 21 and 23 resulting in a discrete electrical discharge as represented by the dash line between those electrode structures in FIG. 5A.
  • a second pulse from Current Pulse Source 28 finds the "P" GTO associated with electrode structure 21 off, while the "P” GTO associated with electrode structure 26 on.
  • a discharge is applied between electrode structures 23 and 26 as represented by the dashed line between those electrode structures in FIG. 5A.
  • the bottom line shows the state of the GTOs during the third pulse in the sequence resulting in an electrical discharge between the cathode of electrode structure 23 and the anode 25.
  • any of the electrode structures 21-26 may be employed as a cathode with its associated "C” GTO turned on and its associated "P” GTO turned off.
  • the "C” and “B” GTOs of the other electrode structures are in the opposite condition while the "P” GTO of the electrode it is desired to function as an anode is turned on concurrently with a pulse from the Current Pulse Source 28.
  • Electrode structure 20 is capable, in the illustrated implentation, of functioning as cathode or anode dependent on the state of its associate "C", "B” and "P” GTOs.
  • each of the electrode structures 20-26 can function alternatively as cathode or anode thereby exhibiting a variable polarity. Further, the discharges may follow any desired sequence utilizing one of the electrodes as cathode while the selection of electrodes as cathode can similarly may follow any desired sequence. As noted above, the electrodes may be positioned in any desired configuration and may be moveable, in known manner, to modify that configuration during operation or initial set-up. For example, the electrode configuration described above establishes an essentially conical inter- electrode space when the central cathode 20 is considered. Other, non-conical, configurations are contemplated by the present invention.
  • treatment zones may be "stacked" (multiple treatment zones positioned sequentially in the particle path) with different zones having the same or different electrode configurations.
  • a magnetic field coil with an adjustable power supply may be provided in a manner known to those skilled in the art. Particulate matter to be treated, and gases for plasma formation and/or stabilization, may be introduced into the reaction zone in any known manner, in accordance with the teachings of the incorporated patent, for example.
  • Incineration is a common procedure for the treatment of wastes, and particularly solid wastes.
  • oxygen penetration through the whole depth of a solid is essential.
  • incinerator this is not possible because a compromise must be made in view of the different components of the feed, size of particles, amount of excess air used and the limited exposure time to the combustion conditions.
  • feed stock heating in an incinerator takes place from the outer surface inward.
  • the oxygen-containing matter within the feedstock does not contribute to oxidation until pyrolysis temperature is reached.
  • pyrolysis is a reaction dependent on the contents of the material being acted upon with no external reactants.
  • the results of pyrolysis are a partial oxidation (dependent upon the internal oxygen) with the resultant typically being a microporous solid.
  • Such products when suitably conditioned, have application as filter media and as sorptive materials (absorbents, occluding agents, etc) .
  • a typical rate of heating in a plasma reactor of the type described above is on the order of l ⁇ ' ⁇ K/second.
  • this rapid heating provides a rapid attainment of pyrolysis temperatures.
  • the reactions obtaining in the treatment zone (in the inter-electrode space) of the reactor described above can accurately be described as plasmalytic pyrolysis—"plasmalysis.”
  • plasmalytic pyrolysis a degree of treatment not attainable by prior art incineration processes, or other processes known to the inventor.
  • An essential condition for plasmalysis within the treatment zone/inter-electrode space is the establishment of an atmosphere free of ambient oxidants as may be accomplished by utilization of a relatively small amount of inert gases such as argon, a gas known for use as a plasma forming gas within the context of plasma reactors known to the prior art. It should be noted that, (in contrast to prior art plasma devices) the plasma reactor of the present invention shows great stability of discharge with small quantities of plasma forming gas. In addition to bulk reduction (an intended re ⁇ ult of incineration, for example) treatment in accordance with the method of the present invention may also address environmental concerns.
  • Conversion of materials having little or no economic value is another benefit of treatment in accordance with the present invention.
  • the plasma treated residuum from colliery spoils may be employed in cement production. Trimmings or like waste of manufactured composite structures may be similarly treated. Casting sand and contaminated soils may be treated to render them non-toxic to ease disposal. Dependent on their constituents, fuel values may be released as thermal energy and metal constituents may be recovered. Further treatment of waste treated by plasmolysis (by oxidation or reduction as appropriate, for example) may be employed to provide materials having enhanced economic value.
  • Waste material to which the method of the present invention can be advantageously applied include, essentially any matter which may be pyrolyzed and which: will benefit from bulk reduction; and/or presents environmental concerns; and/or may be employed to produce valuable constituents from material having little or no economic value.
  • Municipal solid wastes and dry sewer sludge may be advantageously treated in accordance with the present invention.
  • colliery spoils may be treated as may contaminated soil and toxic casting sands. Indeed, it has been determined that waste oil may be successfully intermixed with these and other waste materials with the waste oil contributing to the process. For example, it has been determined that incorporation, and particularly impregnation, with waste oils accelerates rather than slows down the process of the present invention. Indeed, it has been determined that a mixture of waste oils with electric furnace dust can be successfully treated in accordance with the present invention.
  • the present invention may be practiced such that the resultant is a useful pozzolanic material or cement. Resulting thermal effluents may also be employed, in known manner, while valuable constituents may be recovered. The benefits are dependent on the desired final product and the available or desired waste feedstocks. Accordingly, within the context of the above discussion, the invention may be practiced otherwise than as specifically described.

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Abstract

La présente invention concerne un procédé d'élimination des déchets sous l'effet d'un plasma. Une pluralité de structures d'électrodes (14) sont positionnées de façon à définir une zone de réaction associée à l'espace inter-électrodes. Cet espace inter-électrodes étant conditionné (notamment par ionisation préalable), le procédé consiste à produire une série de décharges électriques discrètes dans toute la zone de réaction (13). Selon une réalisation préférée, la zone de réaction (13) est soumise à une suite de décharges électriques discrètes selon des intervalles de temps inférieurs à la période de stationnement du matériau à traiter dans la zone de réaction, de façon que les déchets se pyrolysent pendant leur transit dans la zone de réaction (13).
PCT/US1995/013317 1993-08-19 1995-10-20 Procede plasmalytique d'elimination des dechets Ceased WO1997014528A1 (fr)

Priority Applications (9)

Application Number Priority Date Filing Date Title
US08/109,606 US5403991A (en) 1993-08-19 1993-08-19 Reactor and method for the treatment of particulate matter by electrical discharge
US08/249,153 US5626249A (en) 1993-08-19 1994-05-25 Plasmalysis treatment method for waste matter
EP94925857A EP0722376A4 (fr) 1993-08-19 1994-08-12 Traitement de la matiere particulaire par decharges electriques
JP50708994A JPH09501794A (ja) 1993-08-19 1994-08-12 電気放電による粒状物質の処理
PCT/US1994/009146 WO1995005263A1 (fr) 1993-08-19 1994-08-12 Traitement de la matiere particulaire par decharges electriques
ZA946162A ZA946162B (en) 1993-08-19 1994-08-16 Reactor and method for the treatment of particulate matter by electrical discharge
CN94109323A CN1103232A (zh) 1993-08-19 1994-08-19 电气放电处理粒料用的反应器和方法
US08/521,275 US5605640A (en) 1993-08-19 1995-08-30 Reactor for the treatment of particulate matter by electrical discharge
PCT/US1995/013317 WO1997014528A1 (fr) 1993-08-19 1995-10-20 Procede plasmalytique d'elimination des dechets

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
US08/109,606 US5403991A (en) 1993-08-19 1993-08-19 Reactor and method for the treatment of particulate matter by electrical discharge
US08/249,153 US5626249A (en) 1993-08-19 1994-05-25 Plasmalysis treatment method for waste matter
PCT/US1995/013317 WO1997014528A1 (fr) 1993-08-19 1995-10-20 Procede plasmalytique d'elimination des dechets

Publications (1)

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WO1997014528A1 true WO1997014528A1 (fr) 1997-04-24

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4509434A (en) * 1981-02-27 1985-04-09 Villamosipari Kutato Intezel Procedure and equipment for destroying waste by plasma technique
US4998486A (en) * 1989-04-27 1991-03-12 Westinghouse Electric Corp. Process and apparatus for treatment of excavated landfill material in a plasma fired cupola

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4509434A (en) * 1981-02-27 1985-04-09 Villamosipari Kutato Intezel Procedure and equipment for destroying waste by plasma technique
US4998486A (en) * 1989-04-27 1991-03-12 Westinghouse Electric Corp. Process and apparatus for treatment of excavated landfill material in a plasma fired cupola

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
THESIS TO GRADUATE SCHOOL OF MINNESOTA, April 1991, STEPHEN A. VRCHOTA, "Use of Sustained Shockwave Plasma Reactor for The Recovery of Metals From Electric Arc Furnace Dust", pp 1-97. *

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