RU2725411C2 - Method of solid domestic wastes plasma recycling and mobile installation for implementation thereof - Google Patents

Abstract

FIELD: removal and processing of solid wastes.SUBSTANCE: invention relates to a method and a mobile installation for processing wastes of processing, municipal, industrial and other industries containing organic substances. Method comprises feeding raw material into a shredder and grinding, transporting the prepared material with a belt conveyor to a plasma reactor, melting the material in the reactor chamber by low-temperature electric arc plasma, removal and afterburning of gases with the help of electric arc plasmatron, accumulation of mineral part of wastes in plasma reactor, removal of mineral residue as required. Recycled raw material is represented by solid domestic wastes, wastes are recycled using alternating and direct currents in a plant - a plasma reactor with an afterburner chamber and an electric arc plasmatron, introduction of recycled material into reactor is performed by dosed supply to central part of reactor supplied to combustion zone of three low-temperature plasma arcs, removal of gases is carried out in afterburning chamber, where they are decomposed and after-burnt with low-temperature plasma generated by electric arc plasmatron, removal of neutralized gases into atmosphere, drainage of melt of mineral part of wastes from reactor is performed with possibility of mechanization; the whole volume of melt is mixed by means of uniform magnetic field generated by magnetic yoke.EFFECT: technical result is to reduce time spent on recycling wastes, and to increase reliability of the plant with possibility of operation in continuous mode.2 cl, 6 dwg

Description

The invention relates to a method for processing waste from processing, municipal, industrial and other industries containing organic matter.

A known method of processing household and industrial waste: municipal solid waste and industrial waste containing compounds of heavy non-ferrous metals. The method includes loading waste with fluxing additives into a bath of slag melt bubbled into the supplied gas into an electric furnace with an electrode immersed in a slag melt at a specific power of 400-1500 kW / m ² , blast intensity 0.3-0.5 nm ³ / t⋅min and temperature melt 1450-1600 ° C. In this case, the afterburning of the emitted combustible components, the utilization of dust and heat of the exhaust gases are carried out. Waste is loaded and gas is supplied to the near-electrode zone of the electric furnace, the volume of which is defined as the volume of the cylinder with a diameter equal to 2.38 d _e , the height of the cylinder equal to the value of N _e + d _e / 2, where d _e is the diameter of the electrode, m; N _e is the burial of the electrode into the slag melt, m. Gas is supplied to the melt with a flow rate in the range of 50-150 nm / s. Iron-containing flux is introduced into the melt in an amount necessary to maintain the iron content in the slag melt within 10-15% (see patent RU No. 2349654, IPC C22B 7/00, F23G 5/00, publ. March 20, 2009, bull. . No. 8).

The disadvantages of this method are: the need for preliminary mixing of waste with fluxing additives; maintaining the temperature of the slag melt in the range of 1450-1600 ° C, which leads to high energy costs and the need for expensive heat-resistant materials; the need for bubbling of slag melt, which complicates the design of the installation.

A known method of processing solid household and industrial waste and installation for its implementation, which relate to the field of waste processing. The method includes preparing the mixture in the form of a mixture of waste with flux, loading the mixture and melting it in the open-hearth furnace bath at a temperature of 1450-1500 ° C, where the evolving combustible components are removed to the afterburner with the exhaust gas heat recovery, and the exhaust gases are cleaned from the bag filter, and the flue gas cleaning from carbon oxides and nitrogen oxides is carried out in a catalytic apparatus (see patent RU No. 2523202, IPC C22B 7/00, F23G 5/00, published on July 20, 2014, bull. No. 20).

The disadvantages of this method are: the need for preliminary mixing of waste with flux; the introduction of additional fuel into the furnace during waste incineration, which increases the amount of flue gases; the use of expensive catalysts (vanadium or titanium dioxide) for cleaning flue gases, requiring frequent replacement.

Known plasma chemical reactor for processing solid waste, which is made in the form of a shaft furnace with a loading device, melting chambers, a gas outlet and a drain hole. It includes a solid waste drying chamber sequentially located in the mine from top to bottom with plasma generators for supplying heated working gas in an amount of 2 to 6 equally spaced around the circumference of the plasma reactor, a solid waste gasification chamber with plasma generators for supplying heated working gas in an amount of 2 to 6 uniformly spaced around the circumference of the plasma reactor, the formation zone of a glass-like slag compound with nozzles of plasma generators for supplying heated working gas in an amount of from 2 to 6, evenly spaced around the circumference of the reactor, and gas from the group including carbon dioxide, air, water vapor, argon, gas from the group including steam, carbon dioxide, hydrogen, argon, air, in the zone of formation of glass-like slag compound can be used as working gas in the gasification chamber as a working gas air or carbon dioxide (see RU patent No. 2406032, IPC F23G 5/027, F23G 5/08, B09B 3/00, publ. 12/10/2010, bull. No. 34).

The disadvantages of the known reactor are: the introduction of additional heat to maintain the molten state of the glass-like slag compound; design complexity due to the introduction of air under a layer of molten slag (sparging); the need for preheating air to 5000-7000 ° C.

Closest to the technical nature of the claimed invention is a plasma-chemical method for processing solid household and industrial waste, which relates to the processing of waste processing, municipal, industrial and other industries containing organic matter. The known method includes loading them with preliminary separation by separating glass, concrete, ceramics and metal; drying with partial pyrolysis of organic matter in a shaft furnace; mixing the processed mass of waste with their further pyrolysis. A reduction in the temperature of this process to 500-850 ° C is achieved as a result of exposure to the reducing plasma-chemical components obtained by the steam-oxygen conversion of methane with an increased flow rate of steam supplied countercurrent to the moving waste. Recycled process gas leaving the shaft furnace is cleaned in scrubbers and separated into fuel gas supplied to both the methane converter and the recovery boiler, upon receipt of the reducing gas, with the partial addition of natural gas and oxygen. The waste gases from the recovery boiler are cleaned in the adsorber by contact with fine-grained lime, in addition, part of the resulting reducing gases is consumed in the lower part of the reactor during an instant heat stroke by burning soot and dust particles coming from a hot gas cyclone with dioxins deposited on them , furans and other harmful components in an oxygen atmosphere, and the resulting reducing gases can also be sent as synthesis gas to the production of methanol, dimethylether, motor fuel and other products. The invention allows to reduce the energy intensity of the method (see patent RU No. 2478169, IPC F23G 5/00, C22B 7/00, publ. 03/27/2013, bull. No. 9).

The disadvantages of this method are: the use of oxygen and natural gas; the processes of afterburning, decomposition and gasification of the feedstock proceed at a temperature of 500-850 ° C; the process of production of fuel gas directly depends on the composition of the feedstock, which complicates the process of processing solid domestic and industrial waste.

The closest device in technical essence to the claimed invention is an electromagnetic technological reactor containing a reaction chamber having a bottom, side walls and a cover, input devices for processed materials and output of processed products, three rod electrodes placed at the same distance from the longitudinal axis of the reaction chamber and under angle of 120 ° to each other and a slope of 5-7 °, one rod electrode in the center for heating the melt, an electromagnet in the form of a closed yoke enclosing the reaction chamber with three symmetrical pole tips on which series windings are located, one output of each winding is connected to the corresponding the electrode, at the bottom of the bottom of the reaction chamber in the center of the diameter of the inscribed circle is installed in the water-cooled clip of the tap hole (see patent RU No. 2432719, IPC Н05В 7/18, Н05В 7/22, published on 10.27.2011, bull. No. 30).

The disadvantages of the known reactor are: the lack of a gas exhaust system combined with the afterburning of exhaust gases; lack of an exhaust gas purification system; It is intended only for the processing of basalt rocks and silicon-containing materials.

The claimed group of inventions is aimed at solving a single problem, which consists in the disposal of solid household and medical wastes by burning them in a plasma-arc reactor and decomposing the resulting gases in the low-temperature plasma region generated by the electric arc plasmatron with minimal energy consumption with more stable operation of the installation, as in continuous and cyclic modes.

The technical result of the claimed group of inventions is to reduce the time spent on waste disposal and increase the reliability of the installation with the ability to work in continuous mode, as well as the installation on the trawl with the possibility of its transportation.

In order to achieve the technical result provided by the invention, in a method for plasma utilization of municipal solid waste, which provides for the supply of raw materials to a shredder and its grinding, transportation of the prepared raw materials by a conveyor belt to a plasma reactor, melting of the raw materials in the reactor chamber by means of a low-temperature electric arc plasma, gas evacuation and afterburning using an electric arc plasma torch, accumulation of the mineral part of the waste in a plasma reactor, removal of the mineral residue as necessary, according to the invention, solid household waste is used as the utilized raw material, waste disposal is carried out using alternating and constant currents in the installation - a plasma reactor with an afterburner and an electric arc plasmatron , the input of utilized raw materials into the reactor is carried out by means of a metered supply to the central part of the reactor, supplied to the combustion zone of three low-temperature plasma arcs, the gases are removed to the afterburning chamber, where they are decomposed and burned out by the low-temperature plasma generated by the electric arc plasmatron, neutralized gases are vented to the atmosphere, the mineral part of the waste material is drained from the reactor with the possibility of mechanization, the entire melt volume is mixed by means of a uniform magnetic field generated by the magnetic yoke.

To implement the proposed method in a mobile installation containing a reactor with a reaction chamber, which consists of side walls, a lid, a bottom, a lining of the bottom made of climbing bricks, input devices for utilized raw materials, afterburning and exhaust gases containing an electric arc plasma torch connected to an additional power source, operating in direct current mode, a melt output device, three rod electrodes placed in the reaction chamber at the same distance from its longitudinal axis at an angle of 120 ° to each other and having an inclination relative to the vertical longitudinal axis of 5-7 °, an electromagnet in the form of covering the reaction chamber a closed yoke with three pole tips on which the series windings are located, one output of each winding is connected to one of the three rod electrodes, and the other to an AC power source, according to the invention, the installation is designed as a plasma reactor, which cross section flax in the form of a triangle with truncated vertices, the side walls of which consist of water-cooled panels, a flue for mounting the gases generated during plasma disposal is mounted in the reactor lid, a gas afterburning chamber consisting of a cylindrical body is mounted at the end of the flue, inside of which a truncated cone is mounted, perpendicular to it an arc plasma torch was installed on the axis of the gas afterburning chamber with the possibility of covering during its operation by a low-temperature plasma arc stream a cut of a truncated cone and processing of gases removed from the plasma reactor, and a notch was installed in the lower part of the reactor to discharge the mineral part of the utilized waste.

Distinctive features of the proposed method for plasma utilization of municipal solid waste are:

- the input of the processed raw materials without preliminary drying with partial pyrolysis and mixing can significantly simplify the process of waste disposal;

- the lack of recirculation generated in the process of recycling of technical gases with their separation into fuel and exhaust gases greatly simplifies the process of waste disposal and control of installation parameters;

- the use of an electric arc plasma torch allows completely eliminating the use of natural gas and oxygen from the waste disposal process;

- the supply of raw materials to the installation without preliminary separation with the separation of glass and metal can reduce energy costs for waste disposal in a plasma way;

- the use of low-temperature plasma energy and its properties eliminates the steam-oxygen conversion of methane and devices for its production, which increases the efficiency of the plasma waste disposal method.

Distinctive design features of a mobile installation for the disposal of municipal solid waste are:

- the use of a new installation in the form of a plasma reactor with a gas afterburner allows decomposing harmful formations into elementary components with the formation of simple low-toxic compounds;

- the installation of an electric arc plasma torch and a plasma reactor can reduce energy costs for the disposal of harmful gases, for example when burning natural gas;

- installation of an electric arc plasma torch allows to reduce the reaction chamber and the residence time of harmful gases in the afterburner due to the properties of low-temperature plasma;

- the use of a central input of molten raw materials can reduce energy consumption, increase the stability of the reactor;

- the execution of the device in the form of a mobile installation allows you to transport the installation directly to the garbage collection sites, which reduces the cost of waste disposal.

Thus, the implementation of the claimed invention allows you to create a mobile mobile installation for the disposal of municipal solid waste in the installation of a plasma reactor with an afterburner combined with an electric arc plasmatron.

The claimed group of inventions meets the requirement of the unity of inventions, since the group of diverse inventions forms a single inventive concept, moreover, one of the claimed objects of the group — a method for plasma utilization of municipal solid waste — is intended for use in another declared object of the group — a mobile unit with the claimed combination of design features in a plasma reactor with afterburning chamber combined with an electric arc plasmatron, while both objects are aimed at solving the same problem with a single technical result.

Thus, from the prior art in patent documentation and scientific and technical literature, the applicant is not aware of technical solutions containing a combination of features similar or equivalent to those claimed.

The invention is illustrated by drawings and photos, in which:

in FIG. 1 shows a longitudinal section through a plasma reactor;

in FIG. 2 shows a side view of the technological scheme of plasma utilization of municipal solid waste;

photo 3 shows the device of a mobile installation for plasma utilization of municipal solid waste;

photo 4 shows the reactor in operation;

photo 5 shows a general view of a mobile installation for plasma utilization of municipal solid waste;

photo 6 shows a rear view of a mobile installation for the plasma disposal of municipal solid waste.

The proposed method for plasma utilization of municipal solid waste is implemented in a device made in the form of a mobile installation and consists of a plasma reactor 1 (see Fig. 1), which contains three rod electrodes 2 located at the same distance from the longitudinal axis of the reactor at an angle of 120 ° to each other with a slope of 5-7 ° for each electrode 2 relative to the longitudinal axis of the reactor. The reactor 1 in cross section is made in the form of a triangle with truncated angles and has a water-cooled, isolated from each other cover 3, side walls 4 of the reactor 1, bottom 5, while all of them are made of stainless steel. The side walls 4 of the reactor 1 are made of twelve wall panels. Each wall panel of the side walls 4, the bottom 5 and the cover 3 have two inlet 6 and two outlet fittings 7. In the cover 3 for waste supply there is a pipe 8 and a gas duct 9 for exhausting gases. The notch 10 is fixed in the side wall 4. The bottom 5 is equipped with a lining made of cross bricks 11 installed with an inclination from the side wall panels 4 of the reactor 1 to the notch 10. The cross bricks 11 with the bottom 5 are glued with carborundum on liquid glass, which protects the bottom 5 from burning . An electromagnet is installed outside the reactor 1, consisting of a closed yoke 12 with three pole tips 13 oriented inward and symmetrically located, on which series windings are located (the latter are not shown in Figs. 1 and 2) with two leads, the first of which is connected to the corresponding rod electrode 2, and the second to the AC power source 14 (see Fig. 1). The flowing linear currents of the system "power source - series windings - reactor" provide a uniform magnetic field inside the reactor 1, which mixes the melt, thereby eliminating the "stagnant" zone and creates a uniform temperature field in the melt. An gas afterburning chamber 15 is attached to the gas duct 9, consisting of a cylindrical body 16, a flange 17, and a cone insert 18. An arc plasma torch 19 operating from a direct current source 20 (not shown in Fig. 1) is installed perpendicular to the axis of the gas afterburning chamber 15. Waste 21 from the collection point is fed into the receiving window 22 of the shredder 23. The crushed raw material is accumulated in the industrial bin 24. Then it is transferred by conveyor 25 (feeder) to the loading hopper 26, from where it is fed to the reactor 1 through the pipe 8 installed in the lid 3. Using an exhaust fan 27, they are discharged into the atmosphere 28. The reactor 1 is supplied with electric power from an alternating current power supply 14 via the reactor 1 power supply line 29, and the arc arc plasma torch 19 is supplied via the plasma torch power supply line 19. All equipment is mounted on a trailer 31 with the size of the main platform equal to 12 meters. To protect the equipment from environmental influences, everything except the shredder 23 and the conveyor 25 is located in the container (not shown in Fig. 1-2).

The proposed method for plasma utilization of municipal solid waste is carried out as follows: from the collection point, waste 21 is fed into the receiving window 22 of the shredder 23 (see Fig. 2), where they are ground. The crushed raw materials are accumulated in the industrial hopper 24, from where they are conveyed by a conveyor (feeder) 25 into the loading hopper 26, and then fed to the reactor 1 through the pipe 8 installed in the lid 3. A flat layer of finely dispersed electrically conductive material is formed between the basalt layers in the central part of the reactor 1, for example, graphite powder closing three rod electrodes 2 in plasma reactor 1. Then a three-phase power supply 14 is connected (see Fig. 2) and voltage is applied to rod electrodes 2 through line 29. The current flowing along the electrically conductive paths heats them, from which they melt and form three plasma cords. In the process of burning cords of low-temperature plasma, a large amount of heat is released. The nearby layers of minerals begin to melt. As a result, the initial lens of the electrically conductive melt is formed, which gradually grows and crosses three rod electrodes 2. After the formation of a certain amount of melt along the lines of combustion of plasma arcs, the plasma cords are immersed in the melt, as a result of which a working melting zone is formed, formed by ohmic heating by conduction currents. During the start-up of the plasma reactor 1 and its output to the operating mode, the current magnitude is increased from the minimum order of 50A to the operating one of 150-200A using the power source 14. After the reactor enters the operating mode, turn on the arc plasma torch 19. The plasma torch 19 is supplied with direct current from a constant source current 20 along the power line of the plasma torch 30. When the plasma torch 19 is turned on between its cathode and anode (not shown in FIGS. 1 and 2), the arc arc plasma cord lights up, which is blown out of the plasma torch 19 by swirling air flows, forming a plasma torch with a temperature of 3000-5000 ° FROM. After heating the gas afterburning chamber 15 and reaching 1100-1200 ° C in it, the utilized waste is loaded into the reactor 1 through the pipe 8 from the loading hopper 26. After processing the waste in the reactor 1, a mineral residue is formed in the amount of 3-8% of the initial mass of the loaded waste and toxic gases discharged from the reactor 1 through the cover 3 through the gas duct 9 into the afterburning chamber 15. When toxic gases enter the afterburning chamber 15 their decomposition into the simplest chemical compounds, more stable components of toxic gases decompose in the region of the flame of the low-temperature plasma, which is caused by the rather high temperatures of the flame itself and the presence of free active centers (ions and radicals) in it. The neutralized gases can be additionally purified using hydrated lime, activated carbon (not shown in Fig. 1-2), and the heat of the exhaust gases is trapped in the heat exchanger (not shown in Fig. 1-2) and used for heating buildings and structures. From the afterburning chamber of gases 15, the gases are discharged by an exhaust fan 27 into the atmosphere 28 through a chimney (not shown in Fig. 1-2). The discharge of the mineral residue is carried out at the end of the shift or, as necessary, through a notch 10 into a water tank or a special casting mold (not shown in Fig. 1-2). After cooling to 45-50 ° С and solidification of the mineral residue, it is buried at the solid waste landfill.

At the proposed installation, various modes for the disposal of municipal solid waste with a different composition of plastics, wood, paper, cardboard with inclusions of glass, aluminum and iron cans were tested.

Examples confirming the disposal of municipal solid waste

Example 1

According to the method of plasma utilization of municipal solid waste previously shredded in a shredder 23 to a size not exceeding 100 × 10 mm, plastic bottles are conveyed 25 through a feed hopper 26 and fed to reactor 1, where the first stage of their thermal decomposition takes place. The gases formed in this case are discharged through the gas duct 9 to a pre-heated gas afterburning chamber 15 to a temperature of 1100-1200 ° C, where decomposition of complex toxic compounds into elementary components takes place. The disposal time of 1 kg of waste in a plasma mobile unit did not exceed 40 seconds. Productivity for plastic bottles was 90-120 kg / h. The time to set the slag melt to the maximum acceptable level was 7 hours 53 minutes to 8 hours 35 minutes.

Example 2

Analogously to example 1, wastes containing: 70% by weight of plastic bottles, plastic bags, plastic containers; 20% - metal cans; 5% - wood of different varieties; 5% - paper and cardboard. The disposal time of 1 kg of waste averaged 45 seconds, the productivity was 70-105 kg / h. The time to set the slag melt to the maximum allowable level averaged 5 hours 50 minutes.

Thus, we can conclude that the appropriate choice of operating conditions, a mobile unit and the application of the method of plasma recycling of solid household waste according to the invention allows to utilize: plastics, wood, cardboard, paper, glass and other solid household waste.

The proposed group of inventions "Method for the plasma disposal of municipal solid waste and a mobile installation for its implementation" in comparison with prototypes (see patent RU No. 2478169, IPC F23G 5/00, C22B 7/00, published on 03/27/2013, bull. No. 9 and patent RU No. 2432719, IPC Н05В 7/18, Н05В 7/22, publ. 10/27/2011, bull. No. 30) has the following advantages:

- installation of a gas afterburner in a mobile unit together with an electric arc plasmatron allows to utilize various toxic compounds in a short time due to the use of energy and properties of an electric arc plasma;

- the use of an electric arc plasma torch and afterburner for the disposal of toxic gases eliminates the use of natural gas in general from the technology;

- the use of an additionally mounted gas purification unit by the method of irrigation with hydrated lime (milk of lime) allows for better cleaning of the exhaust gases, which may be required, for example, when disposing of medical waste;

- the use of a heat exchanger reduces heat loss to the environment and increases the efficiency of a mobile unit;

- the use of a shredder for preliminary grinding of waste ensures a reduction in energy consumption, stabilizes the operation of the reactor as a whole and allows the separation of metal inclusions;

- the design of the mobile unit on the trailer allows it to be transported at various distances directly to the collection points and storage of municipal solid waste;

- the use of plasma technology reduces the time spent on waste disposal, which simplifies the mobile installation and reduces its geometric dimensions.

- the absence in the design of the mobile installation of a gas recirculation system with separation into fuel gas and exhaust gases, as well as mixing and drying devices reduces the specific energy consumption for waste disposal and increases the efficiency of the installation;

- the use of air as a plasma-forming gas allows to reduce specific energy consumption;

- draining the mineral residue from the side of the plasma reactor can reduce the installation height and improve the reliability of the installation;

- casting the mineral residue in the form of a rectangular parallelepiped reduces the cost of transportation and disposal at the landfill due to the higher density, small amount (3-8% of the initial waste mass) and the correct form of the solidified mineral residue.

All of the above main advantages of the claimed group of inventions, namely, the method of plasma utilization of municipal solid waste and a mobile installation for its implementation, ensure the reliability of the installation and the entire production line as a whole.

Claims (2)

1. A method for the plasma utilization of municipal solid waste, which provides for the supply of raw materials to the shredder and its grinding, transportation of the prepared raw materials by a conveyor belt to the plasma reactor, melting of the raw materials in the reactor chamber by means of a low-temperature electric arc plasma, gas removal and afterburning using an electric arc plasma torch, and the accumulation of the mineral part waste in a plasma reactor, removing the mineral residue as necessary, characterized in that solid household waste is used as the utilized raw material, waste disposal is carried out using alternating and direct currents in the installation - a plasma reactor with an afterburner and an electric arc plasmatron, input of the utilized raw material into the reactor is carried out by means of a metered supply to the central part of the reactor supplied to the combustion zone of three low-temperature plasma arcs, the gases are removed to the afterburner, where they are decomposed and the low-temperature plasma is burned Mine generated by an electric arc plasmatron, the removal of neutralized gases into the atmosphere, the melt of the mineral part of the waste from the reactor is drained off with the possibility of mechanization, mixing of the entire volume of the melt is carried out by means of a uniform magnetic field generated by the magnetic yoke. 2. A mobile installation for implementing the method according to claim 1, containing a reactor with a reaction chamber, which consists of side walls, a lid, a bottom, a lining of the bottom made of climbing bricks, input devices for utilized raw materials, afterburning and gas outlet, containing an electric arc plasma torch connected to an additional power source operating in direct current mode, a melt output device, three rod electrodes placed in the reaction chamber at the same distance from its longitudinal axis at an angle of 120 ° to each other and having an inclination relative to the vertical longitudinal axis of 5-7 °, the electromagnet in the form of a closed yoke enclosing the reaction chamber with three pole tips on which the series windings are located, one output of each winding is connected to one of the three rod electrodes, and the other to an AC power source, characterized in that the installation is made as a plasma reactor that is made in cross section in the form of a triangle with truncated vertices, the side walls of which consist of water-cooled panels, a gas duct is mounted in the reactor lid to remove gases generated during plasma utilization, a gas afterburner is mounted at the end of the gas duct, consisting of a cylindrical body, inside which a truncated cone is mounted perpendicular to the axis a gas afterburning chamber and an electric arc plasma torch is installed with the possibility of covering during its operation a low-temperature electric arc plasma stream cutting a truncated cone and treating the gases discharged from the plasma reactor, and a notch has been installed in the lower part of the reactor to discharge the mineral part of the utilized waste.

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