A major problem facing modern society is the disposal of various waste materials in a manner, which provides destruction of waste, resource recovery and minimizes impact on the environment. Waste are sorted in several classes according to their origin (municipal, hospital, industrial), their nature (mineral, biological, chemical, nuclear), their state (solid, liquid, gaseous) and the level of pollution that they cause (inert, ordinary, special, toxic, hazardous). The classical techniques brought into operation for destruction of waste are the following: reconversion, recycling, biological treatment, chemical oxidation, confinement, incineration and the ultimate solution, the suppression of waste generating processes. This situation however is not satisfactory, indeed to-day some waste are inadequately treated or are not treated at all because of the lack of suitable means. An ideal waste disposal system is one, which is capable of reducing waste to compounds suitable for environmental disposal. Such suitability is, of course, defined in terms of acceptable levels of pollution as determined by a variety of regulatory agencies. In many countries traditionally, waste disposal has taken in the form of direct burial in landfills, or thermal processing of the waste, followed by burial of the solid residue, and release to the atmosphere of the volatile residue. None of these approaches have proven acceptable, due to the fact that the materials released to the environment remain as unacceptable sources of pollution.

The disposal of worn-out tires (WOT), municipal solid waste (MSW) and other waste of such kind has become a major issue over the past few decades in many countries due to space limitations for landfills and problems associated with siting new incinerators. In addition, increased environmental awareness has resulted in a major concern of many large metropolitan areas and to the country as a whole to ensure that the disposal of solid waste is properly handled.

Attempts have been made to reduce the volume and recover the energy content of municipal solid waste (MSW) and other waste through incineration and cogeneration. The standard waste-to-energy incinerator will process the solid combustible fraction of the waste stream, produce steam to drive a steam turbine, and as a result of the combustion process produce a waste ash material. Typically, the ash is buried in a municipal landfill.

Current trends and recent rulings, however, may require such material to be shipped to landfills permitted for hazardous waste. This will substantially increase ash disposal costs. Moreover, there is increased public concern about gaseous emissions from landfills and the possibility of contamination of groundwater. Another disadvantage associated with incinerator systems is the production of large quantities of gaseous emissions resulting in the need for costly air pollution control systems in an attempt to decrease emission levels to comply with requirements imposed by regulatory agencies. In order to overcome the shortcomings associated with incinerator systems, attempts have been made in the prior art to utilize arc plasmatrons to destroy toxic wastes.

The attempt has been made to improve the incineration technique as applied to MSW with the use of pure oxygen instead of air: it is the continuous process"Thermoselect Verfahren"and equipment for realizing same/1/ converting-99 % MSW to secondary raw material resources. The incineration of MSW in pure oxygen at temperature of 2000 C is completed with full gasification of MSW organic ingredients and production of gas energy carrier, so called synthetic gas (further-syngas); the by-products are mineral granulite utilized in the building industry, the alloyed metallic rest (metallic granulite)-a raw material for metallurgy. Moreover, the by-products comprise the residual fractions such as salt mixtures, sulphur etc. having demand in industry.

"Thermoselect Verfahren"process and equipment operate as follows.

Finely divided MSW are overloaded into a preparation chamber, where they are pressed and briquetted. MSW briquettes are fed into a horizontal heated conduit designed for degassing, supplied with a pushing drive. Heat conductivity of pressed briquettes improves; as a result they are dried very rapidly and degassed at temperature of 600 C. Therewith organic portion of MSW is converted to carbon which is fed by gravity into a zone of vertical high temperature reactor together with gaseous decomposition products-carbon oxides, hydrogen, steam, hydrocarbons; all these products enter continuously into the said reactor, where they are treated by oxygen. As a result, a carbonized solid residue is gasified and converted at the temperature of 2000 C to syngas consisting predominantly of hydrogen, carbon monoxide, carbon dioxide, steam, some simple hydrocarbons. Temperature at the upper portion of the reactor is of 1200 C; therewith all the organic substances are destroyed within 4 seconds.

Mineral and metallic ingredients of MSW melt. Such metals as zinc, lead, cadmium, mercury go into gas phase, manganese, chromium, calcium, magnesium go into melt. The elements, which react with oxygen, go into oxide melt. The main components of the mineral melt are oxides of iron, silicon, aluminium. Mineral and metallic melts are unloaded into the homogenizing reactor and granulated with the use of water jets. Owing to distinct viscosity, density and surface tension the melts are separated and granulated. Under such conditions any possibility of inclusion of water into granules is precluded.

Mineral melt (-230 kg/t. MSW) consists predominantly of oxides of silicon, aluminium, iron, sodium, manganese, chromium, calcium, magnesium.

Residues of hazardous admixtures are localized in this granulite. Mineral granulite corresponds to building material requirements.

Metallic granulite is about 29 kg/t. MSW. The main portion of the metallic granulite is low-alloyed iron (>90 %) with admixtures of copper, nickel, chromium, zinc, phosphorus, silicon. Concentration of toxic elements (thallium, cadmium, lead, mercury, arsenic) is very low. Metallic granulite can be admixed to mineral granulite for building industry or used as a raw material for metallurgy and at production of simple cast irons.

So far as"Thermoselect Verfahren"operates with pure oxygen, the volumes of purified gas are about 15 % the volumes of flue gases of the incinerators. The syngas consists of mono-and dioxides of carbon, hydrogen, steam, small drops of melted mineral substances, volatile vapours of heavy metals and includes hydrogen chloride, hydrogen fluoride, sulphur and nitrogen oxides, hydrogen sulphide etc. As a result, a multi-stage purification process is used consisting of quenching (rapid cooling of gas from 1200 C to 70 C), dust cleaning, acid and base washing, isolation of sulphur, fine filtration on active coke. Quenching enables to prevent re-synthesis of organic substances, e. g. dioxines, furans and their derivatives. The most portion of steam, heavy metals, their compounds and the most part of hydrogen chloride are separated at this stage. After quenching the syngas is subjected to water treatment. The remaining toxic admixtures, such as hydrogen chloride, hydrogen fluoride, heavy metals traces are separated at this stage. Sulphur from hydrogen sulphide is oxidized to elemental sulphur and separated. At the following base treatment chlorine, fluorine and sulphur compounds are separated from the syngas finally. Final purification of the syngas of the hazardous admixtures is attained at passing through an activated coke filter and a cloth filter.

All the toxic admixtures from the syngas are concentrated in various water flushing fractions, which are then collected for joint treatment. Heavy metal are separated at the stages of precipitation. Remaining water is subjected to evaporation; therewith one obtains salts and regenerates water.

The flushing water loaded with admixtures from the syngas is directed to preparation of water. Technological water quantity in"Thermoselect Verfahren" is 250 kg/t. MSW Average enthalpy of MSW is about 10,000 MJ/t. About 900 nm3 of the syngas are produced from 1 ton of MSW. The syngas is used partly for heating of the degassing conduit and in the high temperature reactor. The surplus syngas is used for generation of electric energy in the gas turbine and for producing heat. Typical composition of the syngas, kg/t (% weight) : CO- 434.4 (43. 44 %) ; CO2,-465. 8 (46.58 %); H2-29. 9 (3 %) ; H2O-28. 3 (2.83 %); N2-8.1 (0.81 %). Waste heat of the apparatus is used for current need for purification of the syngas, for preparation of water, for drying slime etc. In the standard equipment (10 t/h) energy surplus attains 7 MW."Thermoselect

Verfahren"standard production line has production 10 t/h, therefore 75,000 t/a at 85 % loading of the equipment.

"Thermoselect Verfahren"possesses with some shortcomings decreasing its efficiency: High concentration of carbon dioxide (-47 %) as compared to concentration of carbon monoxide (43 %); moreover considerable quantity of hydrogen recombines to steam. This, in combination with combustion of a portion of the syngas in the vertical reactor, lowers regeneration level of the MSW energetic resources. Preliminary thermal treatment of MSW in the horizontal conduit at temperature of 600 C promotes to carrying away of considerable portion of carbon and oxygen, containing primarily in MSW, in the form of carbon dioxide.

Considerable portion of MSW metallic ingredients (4.6-7. 7 %) is oxidized, i. e. transforms to less valuable ceramic ingredients (so-called inserts, of which primary content in MSW was in the range 3.3-7. 7 %). Therewith a portion of oxygen from MSW is used to oxidation of the metallic components. As a result, at unloading MSW condensed products content of the metallic granulate was of 19.8 kg/n. MSW (-2 %); at the same time content of the mineral granulite (predominantly oxide phase) becomes-183.6 kg/t. MSW (-18. 4%).

1. Stay-time of the syngas in the upper portion of the reactor at temperature 1200 C can be not enough for full atomization of carbon radicals and fragments; a portion of this fragments can, with some probability, go away from high temperature reactor zone at degassing of MSW in the degassing conduit.

2. Temperature about 2000 C in the lower portion of the reactor can be not high enough for rapid melting and retaining in the melt of some MSW ceramic ingredients, e.. g. cromium oxide, Cr203 (Tmelt-2266 C), magnesium oxide, MgO (Tmel,-2825 C), calcium oxide (Tmelt-2630 C), zinc oxide, ZnO (Tmelt-1975 C), nickel oxide, NiO (Tmelt-1984 C).

3. Purification technology of the syngas of admixtures consists of a lot of technological operation, there are a lot of capacity equipment with considerably low operation time; the technology requires many manual operations and rather complicated.

The search of means adapted to efficient treatment of waste goes along with fight against pollution. For this purposes, the processing using plasma brings new solutions which are more efficient than traditional technique. The interest of plasma is to provide very high temperature and energy densities, together with an ionized and reactive mediums which can increase the kinetics of the conversion reactions. Plasma technique can advantageously replace conventional burners in incineration plants. The comparison of plasma technique with classical incineration processes should not be limited to the energy and investment cost; it should include other advantages such as better performance, respect of standards, maximum rate of destruction.

The use of arc plasmatrons provides an advantage over traditional incinerator or combustion processes under certain operating conditions because the volume of gaseous products formed from the plasma arc plasmatron may be significantly less than the volume produced during typical incineration or combustion, fewer toxic materials are in the gaseous products, and under some circumstances the inorganic remainders of the waste material can be glassified.

A number of attempts have been made in the prior art to destroy waste material using direct current (DC) arc discharge type plasmatrons/2/. One of such attempt is disclosed in Boday, et. al. US Patent No 4,438, 706. This reference teaches the use of a DC arc discharge plasmatron in combination with an oxidizing agent for the thermochemical decomposition of certain type of waste materials. The plasmatron gas is air, and the waste material in vapor form is introduced along with oxygen down stream of the plasma arc generator, where it is heated by plasmatron gas.

In Faldt, et al. US Patent No 4,479, 433, there is disclosed the use of an arc discharge plasmatron to thermally decompose waste material. Waste material in the form of solid particles must be introduced downstream of the arc to avoid fouling of the plasmatron as a result of particle adherence. Oxidizing

agents such as oxygen and air are mixed with the waste either before, during or after the waste is heated by the plasmatron gas. Sufficient oxidizing agents are required for the complete oxidation decomposition of the waste material.

U. S. Pat. No. 5,280, 757 to Carter et al. discloses the use of a plasma arc plasmatron in a reactor vessel to gasify municipal solid waste. A product having a medium quality gas and a slag with a lower toxic element leachability is produced thereby.

A process for remediation of lead-contaminated soil and waste battery material is disclosed in U. S. Pat. No. 5,284, 503 to Bitter et al. A vitrified slag is formed from the soil. Combustible gas and volatized lead, which are formed from the waste battery casings, are preferably transferred to and used as a fuel for a conventional smelting furnace.

The prior art plasma waste decomposition systems aforesaid suffer from a variety of shortcomings which have prevented their widespread use in commercial applications. One shortcoming results from the fact that the waste material generally cannot be introduced directly into the plasma arc because such introduction causes contamination of the arc electrodes and subsequent erratic operation of the arc. Thus, the waste material is introduced downstream of the arc and is indirectly heated by the plasmatron gas. This technique shortens the high temperature residence time of the waste material, resulting in incomplete decomposition. It concerns especially the multi-component heterogeneous waste containing metal, ceramic and salt ingredients, as well as both high melting compounds and low-melting hazardous metals. As a result, there is a need to combine plasma technological and plasma metallurgical treatment of waste to complete their gasification and to systems provide stable, non-leachable solid products.

The general shortcoming of the prior art processes for treatment of various waste and equipment advanced for realizing same are in incompleteness of the process as a whole especially for heterogeneous, multiple-component waste comprising metal and ceramic components.

Efficiency of any process is specified both by the operations for preparation of waste before electrothermal treatment and by the accompanied operations for cleaning, chemical purification and appropriate isolation of various components of the products obtained.

The most of the shortcomings aforesaid have been eliminated with the use of technology developed and advanced by D. R. Cohn, Surma J. E. , Titus C. H./3/ (US Patents No 5666891/1997,5756957/1998, 5811752/1998, 5908564/1999, 6018471/2000,6037560/2000, 6127645/2000, 6160238//2000.

As an example of these weakly discernible patents one should make reference to US Patents No 6127645/2000"Tunable, Self-Powered Arc Plasma-Melter Electro Conversion System for Waste Treatment and Resource Recovery"/4/, where Cohn D. R. , Surma J. E, Titus C. H. disclosed a tuneable waste conversion systems and apparatus for complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards.

The arc plasma furnace and joule heated melter developed by the authors/4/are formed as a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another. The systems provide the capability for highly efficient conversion of waste into high quality combustible gas and for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or an internal combustion engine. The solid product can be suitable for various commercial applications. The preferred configurations of this systems utilize one or more arc plasma electrodes with an elongated chamber for the molten pool such that the molten pool is capable of providing conducting paths between electrodes with the use of direct induction heating of the melt in the chamber said. Waste is converted in an arc plasma-joule heated melter system utilizing arc plasma electrodes and a plurality of joule heating electrodes. The arc plasma electrode (s) can be configured for operation utilizing alternative current (AC) or direct current (DC). The arc plasma electrodes can also be configured for independent arc voltage and arc current control. The joule heating circuits are configured for simultaneous operation with the arcing electrodes, but without detrimental interaction with the arcing electrodes.

The integrated arc plasma-melter unit 10 for treatment of waste is shown in Fig 1. The unit includes reaction vessel 12 having top 12a, bottom 12b, and

sides 12c and 12d. Reaction vessel 12 further includes at least one port or opening 14a (or a plurality of ports or openings 14a and 14b), through which waste material 40 is introduced into reaction vessel 12. Reaction vessel 12 also includes gas port or opening 16 and metal/slag pouring port or opening 20. Gas exiting from port 16 preferably will enter conduit 18 and will be sent to a scrubber, turbine or the like for further processing. Port 16 may be provided with a flow control valve so that gas formed in reaction vessel 12 may be selectively released into conduit 18. Metal/slag port 20 is designed to have a flow control valve that metal and/or slag may be removed and introduced into metal/slag collector 22.

Metal port 20 may be positioned to protrude through the bottom of unit 12 and elevated a predetermined distance there above. In this manner, port 20 may function as a submerged counter electrode to arc plasma electrodes 24a and 24b. Port 20 may also be provided with inductive heating coils 26 to provide additional heating when it is desirable to pour metal and/or slag.

Inductive heating coils 26 may also be designed to provide cooling when it is desirable to cease pouring metal and/or slag.

Reaction vessel 12 also includes a plurality of AC joule heating electrodes 50a and 50b. Electrodes 50a and 50b may be positioned across from one another on sides 12c and 12d, respectively. In addition, electrodes 50a-50b are positioned so as to be partially or totally submerged in the slag 42 mix when the process is in use.

Air/oxygen and/or a combination of air and/or steam may be added to eliminate char from the melt surface and adjust the redox state of the glass.

Positioning electrodes 50a and 50b at angles 52a and 52b respectively, while simultaneously preventing the escape or release of gas facilitates the replacement of electrodes as needed.

Unit 10 may also include auxiliary heater 30 to assist in glass tapping or pouring. Due to differences in specific gravity, metal in metal/slag layer 42 moves toward bottom 12b in vessel 12. Slag in metal/slag layer 42 exits through opening or port 36a into conduit 36. Conduit 36 may be provided with heating coils (not shown) to ensure that the temperature of slag 44 flowing therethrough is sufficient. Slag conduit 36 is preferably positioned such that slag 44 exits unit 12 and flows in an upward direction.

The temperature of slag 44 is maintained in chamber 30 by heaters 32a and 32b for a time and under conditions sufficient to provide a fluid glass or slag to pour into slag collector 46. Ohmic heaters are suitable for use as heaters 32a and 32b in chamber 30.. Alternatively or in addition to heaters 32a and 32b, the temperature of slag 44 may be maintained by plasmatron 58. Slag 44 then passes through slag pouring conduit 34 and port 38, thereby exiting chamber 30 into slag collector 46.

Magnetic coils 54a and 54b may be utilized for inductive heating and/or mixing. In order to provide the optimum rate of melting commensurate with a particular waste stream being introduced into the combined DC arc plasma- melter unit, additional stirring or mixing beyond that normally produced by the melter portion of the furnace and the DC arc portion of the furnace may be desirable. This may be accomplished by the addition of strategically placed magnetic coils such as coils 54a and 54b to create greater J. times. B forces which in turn causes additional mixing and/or heating in the molten bath. Coils 54a and 54b may be positioned within the metal shell of the furnace, but behind the refractory lining of the melt pool. If the furnace shell is fabricated of non- magnetic stainless steel, the coils may be placed on the exterior of the shell.

Coils 54a and 54b are connected to an AC power supply source. The frequency of the power supply source may vary depending on the material. Secondary plasma off-gas chamber 56 ensures that these oils are converted to noncondensable combustible materials resulting in an enhanced recovery of energy value from the incoming waste materials. Secondary thermal boost system 56 may be placed proximate to or within port 16. This system may include heating elements or an arc plasma in a chamber to provide the desirable or necessary thermal energy to further crack and reform condensable fractions exiting the primary plasma-melter unit.

The systems provide high quality combustible gas for high efficiency conversion of the gas into electricity by utilizing a high efficiency gas turbine or an internal combustion engine. Typical composition of the syngas produced from MSW according to the patents above-enumerated, % vol. : CO-44; CO2,- 2; H2-43 ; CH4-2. The appropriate recalculation to weight percent was done for comparison to Thermoselect Verfahren, % BEC. : CO-63. 4; CO2,-7. 1; H2 - 6. 9; CH4-4.9 ; N2-20. 2. One can see from the comparison that content of

carbon monoxide increased 1.46 times, content of carbon dioxide lowered 6.56 times, content of hydrogen increased 2.3 times, therefore quality of syngas improved.

The systems provide stable, non-leachable products and a gaseous fuel.

The gaseous fuel can be utilized in a combustion or non-combustion process to generate electricity.

The methods and apparatus for such conversion include the use of a molten pool having predetermined electrical, thermal and physical characteristics capable of maintaining optimal joule heating and glass forming properties during the conversion process.

The other prior art systems and apparatus for conversion of waste into useful gas and a stable, nonleachable solid product at a single location with reduced air pollution, including the arc plasma furnace and joule heated melter forming a fully integrated unit with a common melt pool having circuit arrangements for the simultaneous independently controllable operation of both the arc plasma and the joule heated portions of the unit without interference with one another suffer from some shortcomings as well and these shortcomings limited their widespread use in commercial applications.

One of the shortcomings aforesaid results from a need in plurality of joule heating electrodes for more or less uniform heating of the melt pool.

Plurality of electrodes requires a plurality of independent power sources or ballast resistors for simultaneous operation of several electrodes supplied from one power source; this is difficult for implementation, expensive and does not ensure proper uniformity of heating of the whole melt pool.

Another shortcoming-it is difficult and dangerously to use a molten pool as a main gasifying medium for industrial large scale treatment of such waste as outworn tires or municipal solid waste (MSW) where routine production capacity was of 10-20 t/h. Under such production rates a loading conduit diameter must be measured in metres. Actually, when density of waste loaded into a melt is-0.2 t/m3 and production capacity 10 t/h, a MSW volume, which must be passed through a molten pool is-50 m3/h. At the same time a cylindrical pool, containing e. g. 70 ton of molten metal with density-7 t/m3 has a volume-10 m3, i. e. at a height 2.5 m a pool diameter is of 2.25 m. Under gasification of MSW or tires a volume of waste treated increases several orders

of magnitude. Under such ratios it is very difficult to retain a melt in a pool even without considering a volume of gasifying reactant introduced into the same pool.

Next shortcoming is a need in lining of high temperature reactor. Routine electrothermal equipment such as arc furnaces as applied for treatment of gas and condensed materials require availability of refractory lining. Manufacturing of lining introduces many manual operations in the process of waste treatment and results in producing secondary waste from outworn refractory lining.

Moreover using great number of graphite electrodes operating under plasma conditions and in melts results in essential consumption of comparatively expensive electrode graphite.

There is a shortcoming to be specific for outworn vehicle and truck tires, where an oxygen content is very low : problems with conversion of carbon to carbon monoxide at surficial treatment of the molten pool. Pyrolysis of these waste results in floating up large masses of carbon, it is very difficult to provide good heat and mass exchange of the carbon with oxygen-containing gas streams; this results in carrying away of large mass of soot from the molten pool surface.

Once more shortcoming is formulated as follows : all the technical details concerning the process reliability and equipment efficiency remain beyond the scope of the patents above-enumerated including the prototype/4/ : transportation of waste material into a molten pool, mixing waste with plasma and melt, purification of syngas required for using them both in gas turbine and in internal combustion engine etc.

Thus, while such prior art attempts have been useful, there remains a need in the art for a robust, easy to operate waste conversion system which minimizes hazardous gaseous emissions and which maximizes conversion of a wide range of solid waste into useful energy and produces a product stream that is in a safe, stable form for commercial use or that does not require special toxic waste considerations for disposal. It would therefore be desirable to provide a robust, user friendly and highly flexible method and apparatus for processing and converting a wide range of waste materials into useful energy and stable products while minimizing toxic gaseous emissions, thereby overcoming the shortcomings associated with the prior art. Moreover, certain

types of waste streams do not contain materials having proper glassification and/or electrical conducting characteristics. These waste streams can be particularly difficult to process. For example, waste containing materials that do not glassify or vitrify such as tires from automobiles and other vehicles have been difficult to process. Similarly, low-ash producing organics have typically been difficult to process in a manner that produces a glassified product. In addition, highly electrically conductive waste streams with waste metals are not amenable to effective heating in melters operating Summary of the Invention The present invention was developed to overcome various problems associated with a number of prior art destruction processes. More specifically, the present invention comprises a method and apparatus for the large scale destruction of worn-out tires, municipal solid waste and medical waste utilizing a totally sealed system, which is based on combined simultaneous plasma arc and direct induction heating of preliminary briquetted waste in integrated apparatus named further as electrothermal treatment. Electrothermal reprocessing of waste with low content of oxygen is reinforced by injection of oxygen into the melt through metallurgical oxygen lance (s) installed in the apparatus bottom. Using oxygen injection into the molten pool enables to reduce radically electrical power of surficial plasma heating. As a matter of fact, a production rate of a modulus apparatus as applied to outworn tires or municipal solid waste is about 10 t/h. At such productivity electrical power of such apparatus must be of 41 and 14 MW accordingly. It is a great problem to provide such powers taking into account the waste needs and a modern level of plasma technique. Especially it concerns an equipment for reprocessing of outworn tires. Therefore, it is a very actual to use additional saturation of the molten pool with oxygen through bottom or/and side oxygen lance (s). Such technology is selected for an industrial modulus having a production capacity of 10 t/h. Using oxygen saturation of the molten pool results in decreasing a required electrical power from 14 MWt to 6 MWt.

The system of the present invention is capable of effective high temperature electrothermal conversion of outworn tires, municipal solid waste

and medical waste in the medium of oxygen containing gas to fuel gases comprising predominantly hydrogen and carbon monoxide. The conversion is implemented in the sealed system.

It is object of the present invention to reduce radically waste material volume at the initial stage of treatment before entering into the molten pool at the expense of intensive plasma conversion. It is another object of the invention to enhance safety of potentially dangerous process owing to large masses of hydrogen and carbon monoxide at the expense of using of chemically combined oxygen at surficial plasma treatment of the molten pool surface, predominantly steam plasma ; therewith another object is attained- enrichment of syngas with hydrogen and enhancement of heat potential of the syngas transported to production of electrical energy. It is another object of the invention to provide methods and apparatus for converting a wide range of waste materials to useful commercial products or to safe, stable products which are suitable for disposal. It is an another object of the present invention to decrease a required electrical power of a technological line, especially a plasma reactor.

It is another object of the invention to provide methods and apparatus for converting waste materials using frequency melter with direct inductive heating operating according to the"cold crucible technology"in combination with the arc plasmotrons or other type plasmatrons, e. g. high frequency plasmatrons. This combination operates as tunable integrated systems. This plasma induction system combines the advantages of the induction frequency melting unit of direct heating, which can handle a wide range of waste, containing in the general case metallic, ceramic, salt inorganic and organic constituents in varying sizes and aggregate states, with those of the plasma arc, which melts the solid constituents of the waste, destroys any molecular structure of hazardous organic waste, sustains a required electrical conductivity of the melt in the frequency melter to provide a proper coupling of frequency power source with a loading-a melt of metallic, ceramic and salt ingredients.

The direct induction heating circuit operates simultaneously with operation of the plasmotrons without detrimental interaction to each other. Nevertheless, plasma treatment of the melt pool enclosed in the zone of direct inductive heating enhances electric conductivity thereof and, as a result, permanent and

stable coupling of the frequency power source with loading. Frequency of the power source for direct induction heating is selected depending on nature of solid constituents of the waste: low frequency for metallic constituents, high frequencies-for ceramic and salt constituents. It is still a further object of the invention to provide methods and apparatus for converting waste materials using tunable, rapid pyrolysis, thereby providing high purity gases suitable for combustion.

It is yet a further object of the invention to provide methods and apparatus for highly effective conversion of waste materials to gaseous fuel capable of generating electricity through a relatively small, highly efficient gas turbine or internal combustion engine.

It is still a further object of the invention to provide waste conversion units that can be net energy producing and/or that can provide a given level of electricity for outside use by utilizing an auxiliary fuel, such as natural gas, diesel or some other fuel, in varying amounts in the gas turbine or internal combustion engine.

Other objects of the invention are formulated as follows : to lower exploitation expenses at the expense of removing of lining of capacitive equipment; therewith a side goal is attained- elimination of secondary waste; elimination of potential probability of exit of hazardous pollutant like dioxins, furans and their derivatives; elimination of potential probability of exit of technological dust, including aerosols beyond a technological apparatus zone; 'to simplify purification of syngas of hazardous admixtures such as fluorine, chlorine oxides of sulfur and nitrogen; to decrease consumption of construction materials at the expense of full rejection of contact heating of waste at the stages of gasification and removing melt of inorganic ingredients of waste. to increase quality of inorganic products obtained in the process: metals, oxides etc.

These and other objects of the invention are provided by systems which are capable of processing outworn tire waste, municipal waste (MSW), and

other waste materials into stable, nonleachable products that are suitable for commercial use or that can be disposed of without risk to the environment. The systems also minimize air emissions and maximize production of useful gases for the generation of electricity. The present invention provides a compact waste processing system that has the advantage of complete or substantially complete conversion of waste materials into useful gases and/or product streams at a single location. The combination of the arc plasma furnace and the induction melter as a tunable, integrated system with gas turbine or internal combustion engine generating equipment provides a net energy producing waste treatment and power production facility that is capable of being deployed in relatively small modular units and that can be easily scaled to handle large volumes of waste materials.

Waste are briquetted prior to electrothermal treatment without heating not to produce carbon dioxide at this stage. Briquetting operation results in removing air and in increasing of heat conductivity, therefore in providing better contact with electrothermal treatment zone. For this purpose waste materials are loaded into a feed hopper supplied with a receptacle in its lower portion designed for briquetting the waste material by hydraulic press arranged horizontally. The same press forces through a briquette into a short unheated horizontal conduit attached to the electrothermal treatment zone where the waste material enters without preliminary degassing. Upper portion of the zone said is cooled metallic vertical cylindrical plasma reactor. Upper portion of the electrothermal treatment zone of waste material is performed first as a conical widening, then conical narrowing in the form of truncated cones; several plasmatrons (not less three) generating oxygen-containing plasma streams, directed downwards under some angle to the reactor axis, are introduced into the electrothermal treatment zone through the conical widening surface; the zone of plasma treatment grades into the treatment zone in the molten pool induced by direct induction heating of the waste inorganic ingredients in the water-cooled frequency melter.

As a result of such combined treatment the main fraction of waste organic constituent (-60-70 % of the primary mass) is converted to the syngas just in the plasma reactor, "the most resistant"fraction (-30-40 % of the primary mass) is submerged into the melt, degassed and converted in the melt

to low-ash stable products, which, after drawing off the electrothermal treatment zone, are finished up to the products having commercial use.

Plasma reactor is manufactured of stainless steel without lining, equipped with combined water-air cooling along the whole length, that are responsible for stable temperature of 600-700 C is held on the reactor walls.

Several arc plasmotrons (not less three) possessing with permanent electrodes, operating on steam, are introduced in the electrothermal treatment zone through a surface of conical widening; they are directed downwards at some angle to the plasma reactor axis in such a way to provide contact of the plasma streams with the molten pool and lack of direct contact with the reactor wall. Temperature of steam plasma streams exiting the plasmotrons is within 4000-6000 C, temperature in the plasma treatment zone is of 2000-2500 C.

With this object in view the total power of the plasmotrons and the frequency melter is selected in such a way, that input of electrical energy are not less 1.4 MW-h/t. MSW, if an oxygen-containing gas is pure steam. Minimal power requirement to reprocessing of outworn tires with the use of steam plasma to the syngas, containing predominantly hydrogen and carbon monoxide, and low- ash residue of inorganic ingredients are not less 4.1 MW-h/t. Minimal power requirement to reprocessing of hospital waste with the use of steam plasma to the syngas, containing predominantly hydrogen and carbon monoxide, and low- ash residue of inorganic ingredients are not less 1.3 MW-h/t.

It is very difficult to provide so high expenditures of energy for waste treatment as 4.1 MW-h/t. for treatment of outworn tires, moreover it necessary to use the very high heat potential of this kind of waste, therefore the oxygen lance (s) are installed in the bottom of the apparatus for injection of pure oxygen into the molten pool volume. The oxygen said converts a considerable portion of carbon to carbon monoxide in the molten pool volume, provides good heat exchange of the waste with the melt and reduces radically a required electrical power of plasma heating. In this case a terminal role of plasma heating can be reduced to creation of high temperature zone in the upper portion of the electrothermal treatment zone and to providing of the required level of electrical conductivity of the molten pool to ensure a stable coupling of frequency power source with loading and to clean the molten pool surface of carbon floating up to the surface from the volume. At increase of pure oxygen fraction in the

electrothermal treatment zone the required expenditures of telectrical energy reduce and are minimized at full substitution of steam plasma to oxygen.

At a temperature in the waste conversion zone of 1200 C and at stoichiometric ratio of steam plasma and MSW the syngas. has the following composition, % vol. : CO-37.80 ; C02,-0. 062; H2-61. 3; H20-0. 26, CH4, -0. 015; at temperature 1700 C, % vol. : CO-37.81 ; COz,-0. 006; H2-61 ; H20-0. 047, CH4, -0. 001. At increasing temperature to 2200 C the variation in syngas composition is minor, % vol. : CO-37.47 ; CO2,- 0.003 ; H2-60. 4; H20-0. 032, CH4, -0.000013. Temperature of the syngas exiting the plasma reactor is of 1800-2000 C. Both oxygen-containing plasma feed and oxygen feed through a melt is selected in such a way, that a content of oxygen was close to stoichiometric one for a full conversion of the waste organic fraction predominantly to carbon monoxide and hydrogen; admixtures of methane, acetylene are minor. At steam plasma conversion of waste the compounds, including fluorine, chlorine, sulfur, nitrogen, are converted respectively to gaseous compounds having, as applied to environment, a status of toxic substances: hydrogen fluoride, HF, hydrogen chloride, HCI, sulfur oxides, SOx, nitrogen oxides, NOy.

When there is a deficiency in oxygen, sulfur transfers into gas phase in the form of hydrogen sulfide, but a terminal distribution of sulfur between condensed and gas conversion products of the waste material depends on a content of calcium and silicon. Sulfur reacts with calcium, forming calcium monosulfide, CaS to be stable in the temperature range 1000-1900 C, which accumulates in the slag ; when silicon is available, it reacts with sulfur, forming a stable gaseous product-silicon sulfide which accompanies the syngas as an admixture. At simultaneous availability of calcium and silicon sulfur re- distributes between these two elements in equal parts. A sulfur fraction binded into calcium sulfide is utilized as a slag. The sulfur carried away from the electrothermal treatment zone as hydrogen sulfide or silicon sulfide must be caught and reprocessed with the use of the known technology, e. g. the technology developed in the frame of Thermoselect Verfahren on the basis of using reduction ability of hydrogen sulfide. So-called Sulferox Process is used for this purpose, in which sulfur from hydrogen sulfide is. oxidized to elemental sulfur ; therewith the reactant used (iron complex compound) is regenerated.

Vapors of heavy, low-melting metals (mercury, zinc, lead, cadmium) accompany the syngas.

Solid and melted waste inorganic ingredients precipitate in the lower portion of the plasma reactor and enter the frequency melter of direct induction heating (so-called"cold crucible"), where melt of metallic, ceramic and salt ingredients collects. The frequency melter is an appliance made of non- magnetic metal, consisting of vertical, water-cooled elements separated with narrow (1-2 mm) clearances, transparent for frequency electromagnetic field from the coil of frequency power source. The"cold crucible"operates, depending on waste composition, on a frequency in the range 0.44-13. 56 MHz at treatment of the waste, containing large share of ceramic and salt ingredients, or on a frequency in the range 2-350 kHz, if inorganic ingredients are metals predominantly.

Performance of the frequency melter is sensitive of the electrical conductivity of the melt inside the induction volume. Electrical conductivity of the melt is stimulated by arc heating. Walls of the frequency melter are cold, therefore inner surface of the frequency melter which is in contact with the melt is automatically lined with a thin solid layer of the refractory waste preventing a melt of contact with a plurality of copper tubes to be transparent for outer frequency electromagnetic field and forming a wall of induction reactor. In other embodiments the performance of the frequency melters is exhibited as applied to application of low and high frequencies for direct inductive heating of metallic and ceramic loadings accordingly. Mixing the waste material with the melt pool and homogenization of the pool itself is facilitated by electromagnetic forces which stir the melt inside the frequency melter.

Electrical conductivity of melt in the frequency melter must be not lower 1 Siem. /m to keep induction coupling of a generator with a loading, but preferably in the range 1-100 Siem. /m. The melt in the frequency melter is stirred and homogenized by electromagnetic forces, which are arisen in the melt at inducing frequency power from a coil of frequency power source.

The MSW organic and inorganic residues are converted completely both in the molten pool volume in oxygen medium and on surface of the melt in the steam medium. The melt, as it fills the frequency melter, is overflowed from the said melter into the collector. Metals and slag (mineral products, oxide phase)

are taken out from the melt using conventional metallurgical methods.

Temperature in the frequency melter is in the range 1700-2500 C depending on a load composition, power, frequency.

The organic ingredients of waste material are destroyed at interaction with the molten metal and converted to the gas product-syngas consisting of simple molecules such as hydrogen, H2, carbon monoxide, CO, methane, CH4, acetylene, C2H2 etc.; excessive carbon floats up to surface of the molten pool processed by oxygen-containing plasma (e. g. steam plasma) streams distributed on the whole surface of the pool said. Steam streams eliminate carbon, floating up to surface. in the form of carbon monoxide. Metallic, ceramic and salt ingredients melt and overflow from the frequency melter via the pouring pipe located above the coil of the frequency melter. These components are separated from the melt collector with the use routine metallurgical technique.

Pure and halogenated (chlorinated, fluorinated) hydrocarbons, dioxine- and furan-compounds are atomized. Nevertheless, at temperature close to 1200 C traces (-10-4-10-6 weight. %) of the various organic radicals CH_, CH2=, CH3-, atoms O, H, F, Cl, N, S etc. are available in the syngas.

Availability of these radicals, atoms and oxygen results in partial recombination of polychlorinated or fluorinated dioxins and furans and other organic compounds containing benzene rings at 250-450 C at slow cooling. In this invention temperature of the syngas exiting the plasma reactor is of 1800- 2000 C, therefore all the radicals above-enumerated are atomized.

The syngas including, in addition to the fuel components, admixtures of hydrogen fluoride, HF, hydrogen chloride, HCI, sulphur oxides, SOx, nitrogen oxides, NOy, vapours of low-melting heavy metals such as mercury, zinc, lead, cadmium, is directed at the exit from the plasma reactor to cooling, cleaning of technological dust, purification and utilization.

In accordance with the available statistics of the industrial incinerators, the syngas, directed to cleaning of technological dust and to purification of chemical impurities, has the next composition according to admixtures: Disperse phase 5-6 mg/m3 Hydrogen fluoride, HF 10 mg/m3.

Hydrogen chloride, HCI 250 mg/m3

Nitrogen oxides, NOx 200 mg/m3 Sulphur oxides, SO2 200 Mr/M3 The syngas must be purified to the level at least, mg/m3 : Content of dust Less 1 Hydrogen fluoride, HF 1 Hydrogen chloride, HCI 10 Nitrogen oxide, NOx 200 Sulfur dioxide, SO2 50 Overall concentration of the polychlorinated dibenzodioxines and dibenzofuranes (PCDBD, PCDBF) < 0.0000001 Cadmium and thallium 0.05 Mercury 0.05 Overall concentration of lead, cobalt, chromium, manganese, nickel, arsenic, tin, copper, bismuth-0. 5 As a matter of principle, the syngas may contain and other admixtures, e. g. hydrogen sulphide, but purification of this admixture is not discussed here, because this problem is solved technically, for example in the process Thermo select Verfahren on the basis of using reduction ability of hydrogen sulphide.

So-called Sulferox Process is used for this purpose, in which sulphur from hydrogen sulphide is oxidized to elemental sulphur; therewith the reactant used (iron complex compound) is regenerated.

Though dioxins and furans and their halogenated derivatives are demolished at temperature of 1200 C during 4 sec. , it is known, that they can recombine within 250-450 C again at slow cooling, but use of quenching operation with a rate not lower 106 C/s results in prevention of this recombination. Quenching is rapid cooling of gas from 2000 C to 70-90 C.

Quenching enables to escape formation of organic substances like dioxins and furans, so far as there is no recombination of dioxins and furans at temperature in vicinity of 70-90 C.

One should note, that at temperature of 1700-2500 C degree and rate of destruction of organic radicals and benzene ring fragments is much more

high than in the process Thermo select Verfahren, therefore in the general case there is no a need in quenching of syngas. Nevertheless, rapid cooling of syngas is essential in any case for prevention of the low temperature reaction CO->'/2 C02 +Y2 C, for following cleaning of the syngas of technological dust and hazardous admixtures; therefore a recuperative heat exchanger is installed at the exit from the plasma reactor, in which the syngas is cooled from temperature 1700-2500 C to 70-90 C. Quenching rate is ~1 o6 c/c automatically realized in a recuperative heat exchanger provides passive safety of potentially possible recombination of residues of polychlorinated dioxins, furans and their derivatives.

The conduit for transportation of the syngas into the utilization zone comprises, except the recuperative heat exchanger, installed one after another an appliance for cleaning syngas of technological dust and an unit for chemical - sorption purification of the hazardous admixtures aforesaid.

In the general case cleaning of syngas is two-stage: in electrofilter and in cermet filter made of anisotropic metal ceramics supplied with impulse ejection regeneration of the filtering surface according to blow-back principle.

The bulk of technological dust with sizes more 1 micron (above 95 %) is caught in the electrofilter. Fine (ecological) cleaning of the syngas of remaining technological dust (1-5 %) is conducted with the use of anisotropic cermet filter, which catch 99.9 % of the aerosols with sizes within 1-5 microns. The portion of dust caught in the cermet filter contains practically in full the heavy low-melting metals aerosols condensed in recuperative heat exchanger.

Analysis of the dust fractions caught in the cermet filter (-0. 18 kg) exhibits, that a content of the heavy metals aforesaid in the fine dust is (in kg. ) : cadmium, Cd - 0. 003-0.004 ; mercury, Hg-0.0002-0. 0006; lead, Pb-0.1-0. 15; zinc, Zn- 0. 06--0. 09.

The syngas consisting of hydrogen, carbon monoxide with small admixtures of steam, carbon dioxide, methane and containing admixtures of fluorine as hydrogen fluoride (HF), chlorine as hydrogen chloride (HCI), sulphur as sulphur oxides (S02, S03) or hydrogen sulphide, nitrogen oxides (NO, N02) is directed to selective purification system to obtain each admixture toxic for environment in the form of stable chemical product having commercial value.

Catching of hydrogen fluoride, HF.

The syngas is directed primarily by a gas blower into the sorption column filled up with granulated sodium fluoride, NaF. Content of HF in the primary syngas-10 mg/m3. At production capacity of the integrated apparatus 10 t/h MSW annual syngas output from the arc plasma furnace-1. 531. 108 nm3. Overall annual output of hydrogen fluoride, HF (during 7446 hours/annum) is 1.531 t. Sodium fluoride sorbs HF, containing in the syngas, at T-150 C practically completely. Pelletized sodium fluoride can absorb hydrogen fluoride up to synthesis of acid sodium bifluoride, NaHFz in the whole volume of the sorption column, i. e to the overweight 47.7 %. In actual practice the recommended overweight is of 12 % to ensure multiple repetition of the cycle "sorption-desorption"without destruction of the sorption granules. It means, that the column containing 1 t. of NaF sorbent can sorb for one cycle-0. 12 t.

HF; it means that a cycle can be repeated 11 times for annum. Desorption of hydrogen fluoride is realized at T-350 C. The desorbed hydrogen fluoride was collected into the condenser at temperature lower the melting temperature (- 87.2 C), then it is collected into preliminary evacuated cylinder ; after filling up the cylinder is sent to a customer.

The syngas purified of hydrogen fluoride is directed into absorption column filled in with water suspension of calcium oxide, CaO; CaO catches hydrogen chloride in the form of calcium chloride, CaCI2 ; simultaneously calcium oxide suspension catches oxides of sulphur and nitrogen in the form of stable chemical compounds which can be separated owing to different solubility in water.

Catching of hydrogen chloride, HCI.

The syngas is directed into the absorption column filled up with water suspension of calcium oxide, CaO. Content in the syngas-250 mg/m3, annual syngas output from the arc plasma reactor at production rate 10 t. MSW/h is 1. 531 108 nm3. Overall annual output of hydrogen chloride, HCI (during 7446 hours/annum) -38.3 t.

Hydrogen chloride is caught practically completely in the column filled in with suspension of calcium oxide, CaO as calcium chloride : Cas) 2 and removed from there periodically as a saturated solution. Utilization of CaClz is not a problem: this salt can be introduced into the salts used for cleaning of the city streets in winter time.

Catching of of sulfur dioxide. SO2.

Content in the syngas-200 mg/m3. At production capacity of the integrated apparatus 10 t/h MSW annual syngas output from the apparatus- 1. 531 103 nm3, therewith overall annual output of sulphur oxides (during 7446 hours/annum) -30.62 t. Removal of sulphur oxides from the syngas flow occurs in the same absorption column filled up with water suspension of calcium oxide and results in formation of sulphate and sulphite of calcium (CaS04-CaS03), which are slightly soluble in water. After unloading of the column these products can be dried and then utilized in the production of the building materials.

Catching of of of nitrogen oxides. Noix.

Content in the syngas-200 mg/m. At production capacity of the integrated apparatus 10 t/h MSW annual syngas output from the apparatus- 1. 531 108 nm3, therewith overall annual output of nitrogen oxides, NOy (during 7446 hours/annum) -30. 62 t. Only higher nitrogen oxides can be caught in such a way; they are caught simultaneously with hydrogen chloride and sulphur oxides in the form of calcium nitrates, which are very soluble; therefore, these ones are liberated into the soluble phase together with calcium chloride. The most part of nitrogen oxides is present in the gas products of high temperature reactions in the form of nitrogen monoxide, NO, therefore the uncaught portion of these admixtures will pass the column and go to the exhaust in the permitted quantity. If content of NO exceeds the permitted level, one must install additional equipment for oxidation of nitrogen monoxide and catching in the said absorption column.

At availability of other admixtures, e. g. hydrogen sulphide etc. , one uses standard technology for its purification, already developed as applied to

purification of syngas exhaust. The syngas is directed for it to additional washing. Then, at a need, the syngas is directed to final purification on coke filter and is sent to utilization.

Syngas flow having composition, % vol. :. ) CO-37.80-38 ; Cl2,-0. 1- 0.2 ; H2-61-61. 3; H20-0. 3-0.4, CH4,-0. 01-0. 02 is directed, at a need, to purification of other admixtures, e. g. hydrogen sulphide, and further to production of electrical energy into a gas turbine or to an internal energy engine.

The computer is used for monitoring and control the process parameter according to technological order. Parameters of both the arc plasma reactor and the frequency melter are controlled to provide an appropriate operating mode of processing of the waste materials depending of their nature and feed.

Brief Description of the Drawings.

For a fuller understanding of the present invention, reference is had to the following description taken in conjunction with the accompanying drawings, in which: Fig. 1 is a block diagram showing a known tunable, self-powered arc plasma-melter electro conversion system for waste treatment and resource recovery"/4/, where Cohn D. R. , Surma J. E, Titus C. H. disclosed a tunable waste conversion systems and apparatus for complete or substantially complete conversion of a wide range of waste streams into useful gas and a stable, nonleachable solid product at a single location with greatly reduced air pollution to meet air quality standards.

Fig. 2 is a block diagram showing the overall system employing the plasma reactor equipped with arc plasmotrons operating on steam and frequency melter with direct induction heating operating as a fully integrated unit with a common molten bath for conversion of the waste to fully utilizable products; the frequency melter is supplied with the bottom metallurgical oxygen lance (s) for injection of oxygen into the molten pool said ; the block diagram includes a feed of waste material and auxiliary reactants into the system and a

system of cooling, cleaning and purification of syngas of technological dust and admixtures.

Fig. 3 presents a flow sheet of one of the variants of the"cold crucible"- an frequency melter operating in combination with plasma arc reactor designed for melting of the waste materials containing metallic or/and ceramic ingredients.

Fig. 4 is a schematic diagram showing the details of two-stage cleaning of syngas designed for combustion and generation of electrical energy.

Fig. 5 is a schematic diagram showing the details of fine purification of syngas designed for combustion and generation of electrical energy.

Description of the Preferred Embodiments.

Referring to Fig. 1, there is shown a block diagram showing a known tunable, self-powered arc plasma-melter electro conversion system for waste treatment and resource recovery"/2/. Fig. 1 is described in detail in the section Background of the Invention.

Referring to Fig. 2, there is shown a block diagram of the destruction system 1 for large scale treatment of outworn tires, municipal solid waste (MSW) and medical waste designed in accordance with the present invention. It is a block diagram showing the overall system employing the plasma arc reactor equipped with arc plasmotrons operating on steam and frequency melter with direct induction heating operating as a fully integrated unit with a common molten bath for conversion of the waste to fully utilizable products; the block diagram includes a feed of waste material into the system and a system of cooling, cleaning and purification of syngas of technological dust and admixtures.

The plasma-frequency induction system 1 is configured to process both solid and viscous liquid waste materials. Typically, although not necessarily, the waste is heterogeneous, i. e., it is composed of different

chemical compounds or substances, rather than a single chemical compound or substance.

The system consists of the following elements. Vertical cylindrical plasma reactor 28 is made of stainless steel, supplied in its lower portion first with conical widening 13, then conical narrowing 14 in the form of truncated cones ; the reactor said is without lining, equipped with combined water-air cooling along the whole length: inner cooling jacket (between the walls 10 and 11) is cooled by air stream, the outer cooling jacket (between the walls 9 and 10) is cooled by water flow. As a result a temperature on the inner reactor wall is of 600 C, a temperature on the outer wall is close to a room temperature.

From above the reactor is closed with a detachable cover 41. Several arc plasmotrons 12 (not less three) possessing with permanent electrodes, operating on steam, are introduced into the electrothermal treatment zone through a surface of conical widening 13; they are directed downwards at an 45° angle to the plasma reactor axis in such a way to provide contact of the plasma streams with the molten pool and lack of direct contact with the reactor wall. Three (or more) piasmotrons said are disposed on the surface 13 at a degree 120° to each other; the angle between the plasma reactor axis and an DC plasmotron axis is in the range 30-45° ; the angle between the generatrixes to the surfaces of conical widening and narrowing is of 90°. These angles are selected in such a way that the axis of the plasmotrons said were set onto surface of the molten pool between the center and the margins and nowhere touch the reactor wall. Each arc plasmotron 12 is supplied from an individual thyristorized rectifier 37; each is supplied with overheated steam generator 38 with a damper 39 for suppression of steam feed fluctuations.

When a plasmotron operates on oxygen, there is no damper. Temperature of oxygen-containing plasma streams exiting the plasmotrons is within 4000- 6000 C, temperature in the plasma treatment zone is of 2000-2500 C.

The zone of plasma treatment grades into the treatment zone in the molten pool induced by direct induction heating of the waste inorganic ingredients in the water-cooled frequency melter 29 of direct induction heating.

The water-cooled frequency melter is designed for direct induction heating of inorganic ingredients of the waste material; it is performed as a so-called"cold crucible"to be transparent to flux of electromagnetic power from the coil 26 of

the frequency generator 36. The melter said is attached to the lower portion of the truncated cone with the use of a flange 15. The melter said is situated coaxially in a coil 26. Diameter of the frequency melter 29 is not less a diameter of the conical narrowing of the plasma reactor 28.

Coupling of the frequency generator with a loading is inductive; the frequency melter is installed coaxially in the coil of the frequency power source.

Frequency melter 18 is manufactured to be transparent for electromagnetic power flux from the coil 26 powered from the frequency power source 36. The melter sheath 27 consists of water-cooled tubular or rectangular extended elements separated by narrow clearances. Clearances are, depending on a composition of the initial waste materials filled in with dielectric inserts sealed with high temperature dielectric cement. Totality of these water-cooled elements, which is transparent for electromagnetic power flux from the coil 26 is defined for brevity as"cold crucible". Technology of such direct induction heating is defined as"cold crucible"technology. Water inlet 24 is in the lower part of each element, water outlet 35 is in the upper part thereof. These clearances are narrow enough to retain a melt inside the induction melter owing to surface tension forces. Nevertheless, these clearances are sealed with refractory dielectric inserts. The frequency melter is situated inside the sheath 25 made of non-magnetic metal and tightened between the cover 15 and the bottom 30. The entries of the coil (33,34) are lead out hermetically via the gaskets 31 a, 31 b in the wall of the sheath 25 towards to the frequency power source 36.

There are the oxygen lance (s) 32 in the bottom 30 of the frequency melter 29 for injection of oxygen jet 32a into the molten pool volume.

Frequency melter said is primarily filled in with ferrous metal scrap to create the initial molten metal pool as a medium for treatment of waste material introduced into the volume of the melt. It is obligatory operation-to immerse the waste material inside the molten pool and to mix the waste material with the melt and to use the power potential of the molten pool in a proper way. Mixing the waste material with the melt pool and homogenization of the pool itself is facilitated by electromagnetic forces, which stir the melt inside the frequency melter volume, and by oxygen jet injected through the oxygen lance 32.

An output terminal of the frequency power source 36 is connected through a variable load adjusting capacitor to the upper high voltage turn of the coil 26. A variable tuning capacitor is used for tuning power on the coil 26.

The plasma-frequency induction system 1 combines many of the advantages of induction, electric arc and plasma heating. The principal metallurgical advantages provided by the system 1 can be summarized as follows: Stirring by induction provides compositional and temperature homogeneity in the melt ; in combination with stirring of the melt surface by plasma jet, it ensures good contact between slag and metal for improved reaction rates.

'The high temperature in the plasma impingement zone (2000-5000 C) results in low slag viscosity and good mixing, thereby improving mass transfer with beneficial effect of reaction kinetics.

The system 1 said is supplied with conduit 16 for removing the melt : it is situated just above the upper turn of the coil 26 and functions as a straight- through pouring the melt as a level of the melt pool ascends above the coil level. The melt is collected in the collector 19, from where it is unloaded through the heat valve 21. The collector 19 is supplied with detachable cover 17 and bottom 20 and with an outer heater 18. After filling in the collector 19 slag and metallic components and directed to utilization.

The conduit 8 for transportation of waste material arranged horizontally is introduced through side surface of the plasma reactor 28 above the conical widening zone 13. The hopper 4 for loading waste 2 is arranged at the end of said conduit 8 distant of the plasma reactor 28. The preliminary dried off waste 2 (municipal solid waste or hospital waste or outworn truck tires cut into pieces to sizes 0.1-0. 2 m. ) is loaded by a grab crane into the hopper 4. The waste material fills the receptacle 6 of the hopper said; after filling in the said receptacle, it is closed by the cover 3, the conduit 8 is closed by vertically reciprocating cutter (not shown in Fig. 2). Then the hydraulic press 5 compresses a waste portion and prepares a briquette 7, of which volume is 10 - 15 % less than a volume in the receptacle 6. A cycle of loading and briquetting is repeated; therewith the briquettes 7 are pushed to the inlet into the plasma reactor 28.

The conduit 40 for removing and transportation of the syngas to cooling, cleaning, purification and utilization is arranged in the upper part of the plasma reactor 28. Next equipment is installed after the plasma reactor: recuperative heat exchanger 43 for cooling the syngas, two-stage appliance 45 for cleaning the syngas of technological dust and the unit 49 for sorption- chemical purification of toxic admixtures. The syngas flow 51 purified of dust and toxic admixtures, containing hydrogen, carbon monoxide, hydrocarbons etc. is directed via the pipeline 51 either to additional purification of any specific admixtures or directly to utilization either into gas turbine, or into internal- combustion engine, or into boiler. The admixtures of chlorine, fluorine, sulfur in the form of hydrogen chloride (HCI) and hydrogen fluoride (HF), sulfur oxides (S02, S03) ; moreover the nitrogen oxides (NO, NO2) are converted to stable chemical compounds (fluorine in the form of anhydrous hydrogen fluoride, chlorine-as calcium chloride (CaCI2), sulfur in the form sulfate and sulfite, nitrogen oxide-in the form of nitrates), isolated, removed from the block 49 via the conduit 52 and directed to utilization.

There is the conduit 42 for returning a bulk of technological dust to the loading hopper 4; small quantity of technological dust containing low-melting heavy metals is removed with the use of a pipe 46 and concentrated in a small volume 47.

The frequency melter, its elements and operation principle are presented more in detail in Fig. 3. The appliances for cleaning syngas of technological dust and for purification of the syngas of toxic admixtures are presented below in Figs. 4 and 5.

Fig. 3 illustrates more in detail a flow sheet of the"cold crucible"-the frequency melter 29 exhibited in Fig. 2 in the general form and designed for melting of the waste materials containing metallic or/and ceramic ingredients.

Frequency melter 29 is manufactured to be transparent for electromagnetic power flux from the coil 26 powered from the frequency power source 36. The melter sheath 27 consists of water-cooled tubular or rectangular extended elements 53 separated by narrow clearances 54. Clearances are, depending on a composition of the initial waste materials filled in with dielectric inserts sealed with high temperature dielectric cement. In metallurgy in some cases the melt is retained inside the"cold crucible"by the forces of the surface

tension, but in this case availability of the sealed inserts is obligatory owing to a specificity of the material processed. The"cold crucible"elements are insulated by alumina coatings. The totality of these water-cooled elements, which is transparent for electromagnetic power flux from the coil 26 is defined for brevity as"cold crucible". Technology of such direct induction heating is defined as"cold crucible"technology. Cooling water flow 57 enters the pipe 24 in the water collector situated in the flange 30, water outlet 35 is in the collector of the flange 15.

The frequency melter is situated inside the sheath 25 made of non- magnetic metal and tightened between the cover 15 and the bottom 30. The entries of the coil (33,34) are lead out air-tight via the gaskets 31 a, 31 b in the wall of the sheath 25 towards to the frequency power source 36.

Frequency electromagnetic field from the coil 26 penetrates freely inside the frequency melter 29 and heats a conducting substances loaded there. The overflow conduit 16 for overflowing melt passes through a section of the frequency melter or alternatively through a non-cooled portion of the flange 15 (this variant is not shown in Fig. 3). The conduit said is lined with graphite or silicon carbide to prevent cooling of melt flow. The frequency melter is situated coaxially inside the water-cooled coil 26 (water inlet 55, water outlet 56) in such a way that a distance from the upper and lower turns of the coil to the upper and lower ends of the clearances were equal to a height of the coil. It is necessary to escape power losses in the upper and lower portion of the frequency melter.

The frequency melter is designed for melting and processing the waste heterogeneous material containing both metallic and ceramic ingredients. introducing of a large mass of the waste materials, possessing with dielectric properties results in lowering electrical conductivity of the molten pool and in decreasing efficiency of heating. Recommended frequency of the high power source is in the range 0.44-13. 56 MHz for melting ceramic materials, direct induction heating of such materials is stimulated by the transferred arc heating the molten pool containing the waste materials.

There are the oxygen lance (s) 32 in the bottom 30 of the frequency melter 29 for injection of oxygen 32a into the molten pool volume.

The same embodiment of the frequency melter can be configured for melting the waste material containing predominantly the metallic ingredients. In this case frequency of the power source is of 2000-2400 Hz and the"cold crucible"sizes are increased 2-5 times. The"cold crucible"of the system 1 is made of the set of rectangular elements made of non-magnetic metal ; both ends of these elements are closed to the water collector. Clearances are sealed with synthetic mica.

Fig. 4 is a schematic diagram showing details of the two-stage appliance 45 designed for cleaning of the syngas flow of technological dust.

The syngas said is cooled preliminary in the cooling appliance 43. According to Fig. 2 the conduit 44 connects the upper part of the recuperative heat exchanger and the lower part of the appliance 45. As a matter of principle any industrial equipment for cleaning the syngas must include the equipment for catching a bulk of technological dust and an appliance for fine cleaning of the syngas to satisfy the requirements for a fuel gas designed for combustion in a gas turbine or in a internal combustion engine. Therefore, the appliance 45 must be two-stage. The first stage is a routine electrical filter 45a which catches a bulk of technological dust containing in the syngas flow entering the conduit 44. The syngas cleaned of a bulk of technological dust is directed into the cleaning appliance 45b designed for fine cleaning of the syngas.

The second stage is appliance 45b for fine cleaning of the syngas is performed as a hopper 61 with a conical bottom 74. The hopper is supplied inside with a hermetically installed barrier 62 which is pierced by the cylindrical tubular filter elements 73 made of anisotropic ceramics. Bottom of each element 73 is hermetically welded up, the top is open. The nozzles 65 for ejection impulse blow-back regeneration are installed above through the cover 64 of the hopper in such a way that each nozzle 65 are aligned along the axis of the appropriate filter element 73. The unit of impulse ejection blow back regeneration of each filter elements 73 include pipeline 66, electromagnetic valve 67 with timer, controlling regeneration impulse time tp (the timer is not shown in the scheme) and with electronic control from the computer, receiver 69 with compressed syngas. Manometer 68 measures pressure in the receiver 69, manometer 72 measures a pressure gradient between the clean and dusty chambers of the filter, manometer 60 measures pressure at the inlet into the

cermet filter. The dusty syngas flow enters via the conduit 44, the cleaned gas flow 48 leaves the cleaning appliance said via the pipe 63. The bottom of the cermet filter is performed as a narrowing cone 74 for unloading of the fine technological dust 46 into the dust collector. This fine dust usually contains aerosols of heavy low-melting metals condensed in the recuperative heat exchanger. The bulk of technological dust is usually returned to the loading hopper via the pipeline 42.

The operation of the appliance for fine cleaning of the syngas thus described is as follows. The dusty syngas flow enters the cleaning appliance 45a via the conduit 59, passes through the filter elements 73 which function according to sieve mechanism. The dust precipitates on the outer surface of the filter elements 73, the syngas flow 48 cleaned of the dust leaves the cleaning appliance via the pipe 63. The dust precipitated on the outer surface of the filter elements said is shaked off by an impulse of compressed syngas entering into the nozzle 65 from the receiver 69 via the electromagnetic valves 67. The impulse aforesaid is intensified by ejection capture of the cleaned gas which provides the bulk of the regenerating gas flow. The electromagnetic valves 67 functions in turn, and the regeneration was realized at 1 second interval. The dust removed from the filter elements 73 during regeneration is discharged via the conical narrowing 75 of the bottom of the cleaning appliance said into the dust collector or directed into the conduit for returning into the waste material flow.

Schematic diagram showing the appliance 49 in details designed for purification of the syngas of the toxic admixtures such as chlorine, fluorine, sulfur in the form of hydrogen chloride (HCI) and hydrogen fluoride (HF), sulfur oxides (S02, S03) ; moreover the nitrogen oxides (NO, NO2) is shown in Fig. 5.

The appliance is designed for in-line purification of the syngas of the admixtures aforesaid and for isolation of these admixtures in the form of stable chemical compounds having a commercial value. The appliance includes a gas blower 77, conduit 48 and two stages for fine purification of the syngas. The conduit 48 connects the open part of the cleaning appliance 45 with lower part of the purification appliance 49. The first stage designed for separation of hydrogen fluoride consists of two sorption column 78. (78a, 78b) filled with pelletized sodium fluoride, NaF, installed in parallel : operating mode of the

column-sorption/desorption, one operates for sorption, another one is standby; after filling in the first column is diverted to the operating mode of desorption, another is connected up for sorption.

After passing the sorption column (78a or 78b) the syngas flow 82a or 82b completely purified of HF is sent for catching other admixtures. The syngas flow containing the toxic admixtures (HCI, SO2, S03, NO, NO2.) is directed into one of two absorption columns 83 (83a or 83b) filled up with suspension of calcium oxide, CaO; this suspension captures all the admixtures remained, which further are separated completely or partly owing to different solubility of calcium salts (chlorides, sulfates, sulfites and nitrates) in water.

Hydrogen chloride is caught practically completely in the column 83b (or 83a) in the form calcium chloride, Cas) 2 and removed from there periodically as a saturated solution 87 which is collected in the evaporator 88. Then the dried salt of CaCI2 89 is directed into the collector 90 and to utilization 91.

Removal of sulphur oxides from the syngas flow occurs in the same absorption column 83b (or 83a) filled up with suspension of CaO and results in formation of suspension of sulphate and sulphite of calcium (CaS04-CaS03 which are slightly soluble in water). The suspension said 84 is subjected to vaporization in the apparatus 85. The dried salt of CaS04-CaS03 is unloaded into the hopper 85 and directed to utilization as well.

Catching of higher nitrogen oxides (excluding the most stable-NO) can be caught simultaneously with hydrogen chloride and sulphur oxides in the form of calcium nitrates, which are very soluble ; therefore, these ones are liberated into the soluble phase together with calcium chloride. But the most part of nitrogen oxides is present in the gas products of high temperature reactions in the form of NO, therefore the uncaught portion of these admixtures will pass the column and go to the exhaust in the permitted quantity. If concentration of nitrogen monoxide exceeds the certificate level for the environment, one should include additional apparatus into the technological route on the basis of ozone processing of the syngas exhaust.

Syngas flow having composition, % vol. :.) CO-37.80-38 ; Cl2,-0. 1- 0.2 ; H2-61-61. 3; H20-0. 3-0. 4, CH4,-0. 01-0. 02 is directed, at a need, to purification of other admixtures, e. g. hydrogen sulphide, and further to

production of electrical energy into a gas turbine or to an internal energy engine.

The present invention lends itself to the use of computer based on monitoring and control systems which provide near instantaneous control of the operation either in the arc plasma reactor 28 and in the frequency melter 29.

Thus, start-up and shutdown sequences can take place safety and quickly. Fig.

2 shows a computer monitoring and control system 54 which is connected to control the arc plasmotrons 12, to power sources 37 and 36, the water pump 23, the heater 18, the drives for briquetting, transportation and feeding waste in the feeding tube 8 and other control systems for cooling, cleaning and purification of the syngas and is also connected to monitor a variety of sensors used to monitor the flow conditions in the various lines and the thermal and other conditions in the system 1. The control system 54 can be configured to provide automatic system operation and safety functions with a minimum of complications.

According to the embodiments in Fig. 2-5 the process for conversion of waste materials and for regeneration of secondary resources is realized with the use of the following operations: preparation of waste material flow for electrothermal treatment; the preparation of waste material includes loading and briquetting; 'transportation of briquetted waste material into plasma reactor; 'generation of streams of steam technological plasma in DC plasmotrons having power supply from controlled thyristorized rectifiers; preparation of the primary molten pool by simultaneous melting of ferrous metal scrap or metal oxides blend ; 'preparations of the bottom oxygen lance (s) for injection of oxygen into the molten pool volume ; 'treatment of waste material briquettes both by steam plasma streams and in molten pool ; oxygen treatment of disintegrated briquettes in the molten pool volume ; electrothermal conversion of the waste organic ingredients to synthetic gas (syngas) consisting predominantly of hydrogen and carbon'monoxide ; inorganic

ingredients are directed to frequency melter of direct induction heating located below the plasma reactor; melting of the inorganic ingredients and homogenization of the molten pool with the use of electromagnetic forces; excitation of electrical conductivity of melt pool in the range 1-100 Siem/m by arc heating to a level required for continuous direct induction heating of the condensed ingredients of the waste material from the coil of frequency power source; removing of soot floating up from the molten pool volume to a surface by oxygen containing plasma streams; as a result the syngas is enriched with hydrogen and carbon monoxide; 'unloading the condensed product of electrothermal treatment of the waste material in the form of melt ; the condensed products are overflowed from the frequency melter via the pipe situated above the coil of the frequency power supply; the ceramic, salt and metallic ingredients of the melt are separated with the use of routine metallurgical technique and technology ; unloading of the metallic, ceramic and salt ingredients of the waste material from the melt pool is continuous as a level of the pool said attains the overflow level ; transport of the synthetic gas (syngas) consisting predominantly of hydrogen, carbon monoxide having temperature 1700-2000 C to recuperative heat exchanger; cooling of syngas outflow in the recuperative heat exchanger to temperature of 70-90 C with a rate not lower 106 C/s ; cleaning of the syngas of toxic vapors of low-melting heavy metals (lead, mercury, zinc, cadmium) by condensation of these metals ; cleaning of syngas of technological dust including aerosols at in-fine passing syngas said through electrofilter and filtration of the flow said through cermet filters made of anisotropic ceramics supplied with blow-back regeneration of filtering surface; distinct catching of the dust bulk at electrofiltration and fine cleaning syngas said on cermet filter including catching of aerosols of low-melting heavy metals : lead, mercury, zinc, cadmium.

'fine purification of the syngas of toxic admixtures such as hydrogen fluoride, hydrogen chloride, sulfur oxides, nitrogen oxides and utilization of the admixtures said as chemical products ; distinct collection of the admixtures said as stable chemical products having commercial value ; 'transportation of purified combustible gases (syngas) to utilization in generation of electric power or heat by combustion in gas turbine, steam boiler or internal combustion engine.

Process of conversion of waste materials in the apparatus according to Fig. 2 is realized as follows as applied to worn-out tires ; other waste materials (municipal solid waste, medical waste, ) are treated in the same manner. The waste materials 2 dried off outdoors under roof are loaded by a grab crane into the loading hopper 4 of the apparatus 1. The waste materials under action of gravity drop down to the bottom of the receptacle 6. When the receptacle 6 is full, the cover 3 is closed ; simultaneously access into the conduit 8, designed for transportation of waste materials into the plasma reactor 28, is overlapped by a cutter (it is not shown in Fig. ) ; simultaneously the hydraulic press 5 designed for briquetting of the waste material is actuated.

The press said compresses a portion of the waste material in the receptacle 6 and forms a briquette 7, of which volume is 10-15 % less than the initial volume 6. Therewith air is forced out into the hopper 3. Then the cutter said is removed from the conduit 8 and the hydraulic press pushes the briquette 7 further into the conduit 9 towards to the plasma reactor 28. The cycle described is repeated. Rate of preparation and transportation of the waste material is correlated with production capacity of the plasma reactor 28 and the induction melter 29.

The electrothermal treatment zone is prepared simultaneously with preparation of waste material. The inner volume of the frequency melter 29 is loaded with ferrous metal scrap. The walls 27 of the frequency melter 29, the arc plasma reactor 28 are cooled by running water. The electrodes of the arc plasmotrons 12 are energized from the DC power sources 38, the plasmotrons are supplied with dry steam. The arc operates in non-transferred operating mode and generate streams of steam plasma. Simultaneously the coil 22 is

energized from the frequency power source 36 resulting in heating and melting the scrap aforesaid. The frequency power source operates generally in the range of 2 kHz to 13,56 MHz depending on a content of non-metallic constituents in the waste material flow. As a result, the melt pool yields in the frequency melter 29. Simultaneously oxygen is injected into the molten pool from below resulting in intensifying of the conversion of the waste in the molten pool said. Temperature of the molten pool volume attains 2000-2500 C, temperature of the arc column is of 4000-6000 C, the average temperature of gas medium above the molten pool surrounded the arc is of 2000-2500 C. At this temperature the electrothermal treatment medium is thermodynamically opportune for predominant conversion of organic ingredients of MSW to hydrogen and carbon monoxide.

The briquettes falling down on melt surface are treated by the descending streams of oxygen-containing (steam) plasmas generated by DC arc plasmotrons 12. Total power of the plasmotrons and the frequency melter are kept in such a way to provide expenditure of energy not less 4.1 MW-h/t.

MSW, when an oxygen-containing gas is pure steam plasma. At introducing pure oxygen into a oxygen lance 32 in the bottom of the frequency melter the expenditures of energy required for reprocessing of the waste reduce proportionally.

All the substances remaining after gasification in the condensed state, mineral and metallic ingredients are subjected to melting. Such elements as zinc, Zn, lead, Pb, cadmium, Cd, mercury, Hg transfer practically completely into gas phase and move together with syngas. Metals, such as iron, Fe, chromium, Cr, copper, Cu, nickel, Ni transfer to the melt.

Melt is collected in the frequency melter 29; on filling the said melter volume the melt overflows via the conduit 16, situated above the coil 26, into the collector of melt 19. The collector 19 is supplied with additional electric heater 18 to retain the condensed products leaving the frequency melter 29 in the molten state. The conduit 16 is supplied with the similar heater when there is a need. Pouring off metallic and ceramic products from the frequency melter 29 is implemented through a heat valve 21in periodical operating mode as a level of the melt attains the top. As an alternative it is feasible stretching off the ingots through a special port in the bottom of the collector 19.

The slag and the metal are subjected to routine chemical and metallurgical processing to separate, to isolate and to utilize the ceramic, salt and metallic ingredients. Mineral and metallic melts are unloaded into homogenizing reactor and granulated with the use of water jets. Owing to distinct viscosity, density and surface tension the melts are separated and granulated. Under such conditions any possibility of inclusion of water into granules is precluded. Mineral melt consists predominantly of oxides of silicon, aluminium, iron, sodium, manganese, chromium, calcium, magnesium.

Residues of hazardous admixtures are localized in this granulite. Mineral granulite (30-85 kg/t. MSW) corresponds to building material requirements.

The main portion of the metallic granulite (46-75 kg/t. MSW) is low-alloyed iron (>90 %) with admixtures of copper, nickel, chromium, zinc, phosphorus, silicon. Concentration of toxic elements (thallium, cadmium, lead, mercury, arsenic) is very low. Metallic granulite can be admixed to mineral granulite for building industry or used as a raw material for metallurgy and at production of simple cast irons.

The syngas possessing with temperature of 1700-2000 C is carried off via the pipe 40 straight-through into the recuperative heat exchanger 43 for cooling the syngas to temperature 70-90 C and for quenching with a rate rate not lower 106 C/s. to prevent recombination of dioxins, furans and their chlorinated and fluorinated derivatives. Low-fusible toxic metals such as Zn, Pb, Cd, Hg are condensed in the recuperative heat exchanger 40 in the form of technological dust. The dusty syngas is directed into the two-stage appliance 45 for cleaning the syngas of technological dust.

The syngas, cleaned of mechanical particles and aerosols, but containing toxic admixtures such as hydrogen fluoride (HF), hydrogen chloride (HCI), sulfur oxides (S02, S03), the nitrogen oxides (NO, NO2), is subjected to additional selective treatment in the series of apparatuses 49 designed to retain and to isolate fluorine in the form of HF, chlorine-as calcium chloride (CaCtz), sulfur oxides as sulfate and sulfite, nitrogen oxide-in the form of nitrates.

The syngas flow 39 purified of dust and hazardous admixtures, containing hydrogen, carbon monoxide, hydrocarbons etc. is directed via the pipeline 38 to utilization either into gas turbine, or into internal-combustion engine, or into boiler.

At availability of other admixtures, e. g. hydrogen sulphide etc. , one uses standard technology for its purification, already developed as applied to purification of syngas exhaust. The syngas is directed for it to additional washing. Then, at a need, the syngas is directed to final purification on coke filter and is sent to utilization.

Syngas flow having composition, % vol. :. ) CO-37. 80-38 ; Cl2,-0. 1- 0. 2 ; H2-61-61. 3; H20-0. 3-0.4, CH4,-0. 01-0. 02 is directed, at a need, to purification of other admixtures, e. g. hydrogen sulphide, and further to production of electrical energy into a gas turbine or to an internal energy engine.

Purification of the syngas of hydrogen sulfide is not discussed here, because this problem has been technically solved e. g. in the process Thermoselect Verfahren, in which sulfur from hydrogen sulfide is oxidized to sulfur elemental according to Sulferox Process; therewith the reactant used (the iron complex compound) is regenerated.

The computer is used for monitoring and control the process parameter according to technological order. Parameters of both the arc plasma reactor and the frequency melter are controlled to provide an appropriate operating mode of processing of the waste materials depending of their nature and feed.

Example 1.

A small-scale prototype of the system 1 including arc plasma reactor 28 and frequency melter 29 supplied with all the technological lines for feeding of the waste materials and unloading of the condensed and gas products has been designed and used for processing a variety of waste materials including crushed outworn vehicle and truck tires. The same apparatus (Unit 1) shown schematically in Fig. 2 was used for treatment of crushed outworn truck tires.

The parameters of the said unit are exhibited below. The tires contain-83 % of organic nature (gross formula C, 2H, 5), 15 % of metal (cord), 1.35 % of sulfur and other admixture of inorganic nature (compounds of nitrogen, aluminium, calcium, silicon etc. ).

Installed power of a controlled thyristorized rectifier 37 (three rectifiers 37 supplying three DC plasmotrons. 12 generating steam

plasma streams are installed, therefore the installed power is 300 kW; DC amperage in DC plasmotron in a steady-state operating mode- 250 A; DC voltage on the electrodes of the DC plasmotron-400 V; # Actual power of the plasma reactor-120 kW; # Steam weight feed through 3 plasmotrons-42. 5 kg/h; 'Steam volume feed through 3 plasmotrons-56. 7 nm3/h. ; # Installed power for the frequency power supply 24-110 kW; # Radio frequency power level-60 kW; # Frequency of the frequency power supply-440 kHz; inner diameter of the cylindrical part of the plasma reactor 28-0.5 m; # Height of the cylindrical part of the plasma reactor 28-1. 5 m ; Inner diameter of the frequency melter 29-0.25 m; Height of the frequency melter 29-0.8 m; Operation pressure in the system 1 in a steady-state operating mode - 1 atm. ; 'Mass flow of the waste material (outworn tires) in the system 1 in a steady-state operating mode-up to 100 kg/h; Number of the bottom oxygen lance (s) -1; # Oxygen feed through the bottom oxygen lance - 63. 7 kg/h; # Argon flow-0. 2 nm3/h ; # Average temperature of steam plasma streams-4000-6000 C; # Average temperature in the MSW treatment zone of the plasma reactor 28 #2050 C ; # Temperature in the volume of the melt pool 29 in a steady-state operating mode-2190 C; 'Mass of the melt unloaded from the frequency melter 29-16.5 kg/h ; Mass of the metal unloaded from the frequency melter 29-14.6 kg/h; Mass of the slag unloaded from the frequency melter 29-1.9 kg/h;

Mass flow of syngas entering the recuperative heat exchanger 43- 190.17 kg/h; Temperature of syngas at the outlet from the arc plasma reactor- 1650 C; Overall mass of technological dust returned from the cleaning appliance 45-0. 08 kg/h; Total mass of chemical products 53 unloaded from the purification columns 49-0.13 kg/h; Total mass flow of the syngas 51 directed to utilization (burning) - 190 kg/h.

Total volume flow of the syngas 51 directed to utilization (burning) - 304 nm3/h.

Composition of the syngas leaving the cooling appliance is as follows (% vol.) : CO-38. 8; C02-0. 2; H2 - 60. 97; CH4-0. 22; CzHz-0. 0002.

Example 2.

The operation parameters of the prototype (Unit 1) exhibited schematically in Fig2.2 with details according to Figs. 3-5 and designed for treatment of municipal solid waste are as follows (municipal solid waste contains to 84 % substances of organic nature, 4.6-7. 5 % ferrous and non- ferrous metals 3-8.5 % glass, ceramics, salts) : 'installed power of a controlled thyristorized rectifier 37 (three rectifiers 37 supplying three DC plasmotrons 12 generating steam plasma streams are installed, therefore the installed power is 300 kW; DC amperage in DC plasmotron in a steady-state operating mode- 250 A; DC voltage on the electrodes of the DC plasmotron-400 V; Actual power of the plasma reactor-87 kW; 'Steam weight feed through 3 plasmotrons-30 kg/h; 'Steam volume feed through 3 plasmotrons-40 nm3/h. ; Installed power for the frequency power supply 24-110 kW; # Radio frequency power level-60 kW;

Frequency of the frequency power supply-440 kHz; Inner diameter of the cylindrical part of the plasma reactor 28-0.5 m; # Height of the cylindrical part of the plasma reactor 28-1. 5 m ; Inner diameter of the frequency melter 29-0.25 m; Height of the frequency melter 29-0. 8 m ; Operation pressure in the system 1 in a steady-state operating mode - 1 atm.; Mass flow of the waste material (MSW) in the system 1 in a steady- state operating mode-up to 137 kg/h; Number of the bottom oxygen lance (s) -1; Oxygen feed through the bottom oxygen lance - 11. 08 kg/h; # Argon flow - 0. 2 nm3/h ; 'Average temperature of steam plasma streams-4000-6000 C; 'Average temperature in the MSW treatment zone of the plasma reactor 29-2350 C; 'Temperature in the volume of the melt pool 29 in a steady-state operating mode-2160 C; 'Mass of the melt unloaded from the frequency melter 29-28.6 kg/h; # Mass of the metal unloaded from the frequency melter 29-15.2 kg/h; # Mass of the slag unloaded from the frequency melter 29-13.4 kg/h; Mass flow of syngas entering the recuperative heat exchanger 43- 178.11 kg/h; Temperature of syngas at the outlet from the arc plasma reactor- 1650 C; 'Overall mass of technological dust returned from the cleaning appliance 45-0. 08 kg/h; # Mass of the low-melting heavy metal unloaded from the cooling appliance 29-0.014 kg/h; # Overall mass of dust containing aerosols of heavy, low melting metals caught in the cermet filters-0. 014 kg/h;

Total mass of chemical products 53 unloaded from the purification columns 49-0.13 kg/h; Total mass flow of the syngas 51 directed to utilization (burning) - 178 kg/h.

Total volume flow of the syngas 51 directed to utilization (burning) - 296.8 nm3/h.

Composition of the syngas leaving the cooling appliance is as follows (% vol.) : CO-38. 8; COz-0. 2 ; H2-60. 97; CH4-0. 22; C2H2-0. 0002.

Example 3: Studies have indicated that the prototype system may be easily scaled up in size to accommodate a variety of waste processing rates. For example, the following operating parameters are anticipated for a large scale version of the system (Unit 2) designed for processing of the heterogeneous waste material including predominantly municipal solid waste (MSW), which contain 75-84 % of inorganic ingredients, 4.6-7. 5 % of ferrous and non-ferrous metals, 3-8.5 % of ceramic and salt components.

Electrothermal reprocessing of waste with low content of oxygen is reinforced by injection of oxygen into the melt through metallurgical oxygen lance (s) installed in the apparatus bottom. Using oxygen injection into the molten pool enables to reduce radically electrical power of surficial plasma heating. As a matter of fact, a production rate of a modulus apparatus as applied to outworn tires or municipal solid waste is about 10 t/h. At such productivity electrical power of such apparatus must be of 41 and 14 MWt accordingly. It is a great problem to provide such powers taking into account the waste needs and a modern level of plasma technique. Especially it concerns an equipment for reprocessing of outworn tires. Therefore, it is a very actual to use additional saturation of the molten pool with oxygen through bottom and side oxygen lance (s). Such technology is selected for an industrial modulus having a production capacity of 10 t/h. Using oxygen saturation of the molten pool redults in decreasing a required electrical power from 14 MWt to 6 MWt.

'installed power of the power source of DC plasmotron-1000 kW; Number of a 3000 kW DC plasmotrons installed into a plasma reactor-4; Total power of the plasma reactor-4 MW; 'Steam weight feed through 4 plasmotrons - 1. 44 kg/h; Steam volume feed through 3 plasmotrons-1920 nm3/h. ; 'installed power of the frequency power source-2000 kW; Frequency of the frequency power supply-2 kHz; # Inner diameter of the cylindrical part of the plasma reactor-2.5 m; # Height of the cylindrical part of the plasma reactor-2. 5 m ; # Inner diameter of the frequency melter-1. 2 m ; Height of the frequency melter-1. 6 m ; Operation pressure in the apparatus 1 in a steady-state operating mode-up to 1 atm.; 'Total mass flow of waste material-up to 10 t/h; # Argon flow-0.5 m3/h ; Number of the bottom oxygen lance (s) -2; # Oxygen feed through the bottom oxygen lance - 1. 475 t/h; 'Average temperature of steam plasma streams-4000-6000 C; 'Average temperature in the MSW treatment zone of the plasma reactor-2450 C; Temperature in the volume of the melt pool in a steady-state operating mode-1500-2300 C; 'Mass of the melt unloaded from the frequency meiter-1. 26 t/h; 'Mass of the metal unloaded from the frequency meiter-0. 48 t/h; 'Mass of the slag unloaded from the frequency meiter-0. 78 t/h ; Mass flow of syngas entering the recuperative heat exchanger- 12.06 t/h; 'Temperature of syngas at the outlet from the arc plasma reactor- 1600 C; Overall mass of technological dust returned from the cleaning appliance - 1. 23 kg/h;

Overall mass of dust containing aerosols of heavy, low melting metals caught in the cermet filters-0. 11 kg/h; Total mass of chemical products unloaded from purification columns -9. 25 kg/h; Total mass flow of the syngas directed to utilization (burning)-12. 06 t/h.

Total volume flow of the syngas directed to utilization (burning) - 26504 nm3/h.

Composition of the syngas leaving the cooling appliance is as follows (% vol.) : CO-38. 8 ; CO2 - 0. 2; H2-60. 97; CH4 - 0. 22; C2H2 - 0. 0002.