WO2007100272A1

WO2007100272A1 - Method for thermally processing solid community wastes

Info

Publication number: WO2007100272A1
Application number: PCT/RU2006/000097
Authority: WO
Inventors: Anatolij Anatoljevich Golubev; Jurij Alexandrovich Gudim
Original assignee: Obchestvo S Ogranichennoj Otvetstvennostju Promishlennaja Kompanija 'tehnologija Metallov'
Priority date: 2006-03-03
Filing date: 2006-03-03
Publication date: 2007-09-07

Abstract

The invention relates to metallurgy and heat power engineering and can be used for processing solid community, medical and certain solid industrial wastes. Said invention makes it possible to carry out a dosposalless waste reprocessing, recycle separated dust and to increase the resistance of a melting furnace lining. The inventive method consists in drying wastes to a moisture content of 5-12% in a hermetically sealed conveyor device with the aid of gaseous nitrogen, which is heated to 150oC by a hot cumulative metallic heat carrier during the melting furnace cooling and in burning wastes on a molten slag surface at a temperature of 1550-1600oC in atmospheric oxygen injected therein by combined burner tuyeres with a supersonic speed.

Description

Non-waste thermal processing method

municipal solid waste

The invention relates to metallurgy and power engineering, and can be used for the processing of municipal solid waste (TKO), medical waste, and some solid industrial industrial waste.

The rapid growth of production and the accumulation by mankind of solid waste products necessitates the creation of rational methods for the processing of such waste, and first of all municipal (household) waste.

There are various methods of processing (disposal) of municipal waste. The most common of them at present are: pressing and burial of waste at specially equipped landfills; processing of the organic component of waste into compost (composting), again in specially equipped areas;

- processing by thermal pyrolysis in a reducing or neutral atmosphere to produce gases suitable for use as a coolant and mineral residue (ash), which usually needs to be buried in specially designated landfills;

- combustion in an oxidizing atmosphere (air), mainly on the grate grids of specially equipped energy boilers.

Typically, the listed methods for processing municipal solid waste are applied after a low-productivity and costly operation.

SUBSTITUTE SHEET (RULE 26) waste sorting, in order to extract and reuse such components as packaging cardboard, glass, plastics, small scrap metal.

The main disadvantage of these methods is the need for the disposal (and, consequently, the constant accumulation) of a fairly large number of toxic products of processing municipal waste.

The most effective and high-performance of the listed methods of processing (utilization) of TKO is their burning. As a result of waste incineration, a small amount of toxic processed products (ash and dust) is formed, which in principle can be reduced to zero. In addition, when burning TKO, a rather large amount of heat is released, which can be used to generate electricity. But when burning TKO, a number of technical and environmental difficulties (problems) arise. The most important of them are the following: low average calorific value of waste burned due to high humidity (30 - 50%) and a significant content of non-combustible components: glass, bones, pieces of metal and construction waste.

As a result of this, as well as due to the use of air for the oxidation of organic components of waste, the burning of garbage occurs at relatively low temperatures (800-1100 ⁰ C), which greatly complicates and complicates (and sometimes even excludes) the possibility of complete burning of the resulting from heating and burning Wastes extremely dangerous for humans and the environment of dioxins and furans.

Due to the fact that the waste incineration process is carried out at low temperatures, the inorganic components of the waste turn into solid ash with a high specific surface, containing a significant amount of harmful substances that are easily washed away

SUBSTITUTE SHEET (RULE 26) from it by atmospheric and soil moisture. Such ashes need to be stored in special coffered storage facilities.

The removal of moisture from the waste when it is burned by known methods is carried out directly in the boiler, this leads to a significant increase in the volume of gases leaving the boiler, requires an increase in the size and cost of gas treatment facilities, and also increases operating costs for gas cleaning.

The dust captured in the filters of gas treatment facilities contains a significant amount of harmful substances (heavy metals in the form of oxides, etc.) and is not disposed of, and is also disposed of in special storage facilities, even during the operation of the most modern waste incineration plants.

Known methods of processing TKO ₅ involving technological and structural methods, partially eliminating the difficulties encountered in the combustion of waste. In particular, it is proposed to incinerate solid household waste in a layer of liquid slag or in a slag melt with a temperature of 1400 to 1500 ° C and feeding them into the melt, blowing the melt to mix it with TKO, an oxygen-containing gas [1,2].

Known methods of processing TKO, providing for the supply of slag melt, to reduce the melting point of the resulting slag, substances with a high content of calcium oxide (CaO) [1,4] or calcium sulfide (CaS) together with non-ferrous metal compounds [2].

To increase the temperature of waste burning, it is proposed to carry out the drying of wet TKO with process gases of the combustion process, either directly in the working space of the burning unit [3], or in a loading device before loading TKO into the unit [4].

SUBSTITUTE SHEET (RULE 26) Known methods have a number of significant disadvantages that impede their real implementation.

It is very difficult in practice to incinerate and dispose of TKO in a layer of molten slag. TKOs have a density (on average up to 1.0 kg / dm ³ ) much lower than the density of molten slag (2.5-4.5 kg / dm ³ ). Therefore, to place TKO (kneading) in a layer of molten slag, it is necessary to blow the slag with oxygen-containing gas [1,2] or hot products of the combustion of hydrocarbon fuel [5].

The molten slag has a relatively low oxidative potential, therefore, the oxidation (burning) of the organic component of the waste proceeds in it extremely slowly and not completely (only to CO), despite the rather high temperature of the slag melt (1400-1500 ⁰ C). The separation of CO and H ₂ O resulting from the combustion into the gas phase from the slag is difficult and also proceeds extremely slowly.

Recommended in [3], to increase the temperature of burning TKO, methods for drying wet municipal waste with hot process gases (temperature approximately 1300-1700 ° C) obtained by burning waste in a loading device before feeding it into a burning device (melting chamber) [4] or directly in it, have significant flaws.

When drying in loading devices, the heating temperature of the waste is not controlled, so it heats up to temperatures at which the formation of dioxins and furans (200-600 ° C) is possible, which carries the potential danger of uncontrolled emissions of dioxins and furans formed into the atmosphere. When drying wet municipal waste directly in the working space of the burning device (melting chamber) due to evaporating moisture, they increase sharply

SUBSTITUTE SHEET (RULE 26) fuel consumption and the amount of exhaust gas from the chamber (estimated 30-50%), which increases the capital and operating costs of gas treatment facilities, ultimately reduces the temperature of the working space in the chamber, the temperature of the exhaust gases and reduces the possibility of rational use (utilization) of exhaust gas heat .

Recommended in [1,2,4] additives to the slag of substances containing only calcium oxide (CaO) or calcium sulfide (CaS) in order to reduce the melting point of the resulting slag, do not allow the use of technogenic industrial metallurgy wastes (dump slag, dust, sludge etc.), ashes of thermal power plants (TPPs) and do not allow you to adjust the composition of the resulting slag within such limits that make it possible to produce such valuable products (commercial products) as slag stone casting, clinker for the cement industry, etc.

A known method of processing household and industrial waste, including preliminary heat treatment (drying) of the waste to reduce humidity, loading it into the melting chamber, burning organic components, afterburning and cleaning the exhaust gases from the melting chamber, utilizing the heat of the exhaust gases, melting the mineral constituents of solid household waste, the release of accumulating slag and metal (see patent RU 2265774, MKI 7: F23G5 / 00), selected by the applicant as the closest analogue.

In the known method, the preliminary heat treatment of the waste is carried out in a layer in an upward flow directly in the gas space above the slag melt bath with an additional supply of heated air above the waste layer. The waste layer is placed above the surface of the slag melt on the grate so that

SUBSTITUTE SHEET (RULE 26) the projection of the area of the waste layer onto a plane located at the level of the surface of the melt, is completely or partially outside the surface of the slag melt. The slag melt is purged with hydrocarbon fuel combustion products with a temperature exceeding the temperature of the slag melt by 10-600 ⁰ C. Gas supply above the surface of the slag melt is carried out from the side of the slag melt bath. The supply of gas for blowing the bath of slag melt is carried out at a level spaced from the bottom of the bath by 5-10 diameters of the jet at its entrance to the melt. Heated air or a mixture of it with hydrocarbon fuel is used as the gas supplied above the surface of the molten slag bath. The temperature of the supplied heated air is 500 - 600 ° C.

The known method of processing household and industrial waste has the following disadvantages: it does not allow to utilize the dust collected in the gas purification from gases leaving the combustion device (melting chamber); frequent stops of the unit for repairing the lining due to its intensive destruction during chemical erosion of the main refractory lining based on calcium oxide (CaO) or magnesium oxide (MgO). It does not allow for efficient waste-free, continuous, environmentally friendly waste processing.

The present invention solves the problem of non-waste processing of municipal solid waste (TKO) and environmentally friendly disposal.

The technical result of the invention is to eliminate the disadvantages of the closest analogue, namely:

SUBSTITUTE SHEET (RULE 26) - ensuring the process of non-waste, efficient processing of municipal solid waste;

- ensuring environmentally friendly disposal of dust trapped in gas purification from gases leaving the combustion device (melting chamber);

- increase the resistance of the lining of the melting chamber.

The technical result is ensured by the fact that in the non-waste heat treatment method for solid municipal waste, which includes drying the waste, loading it into the melting chamber, burning organic components, afterburning and cleaning the gases leaving the melting chamber, utilizing the heat of the exhaust gases, melting the mineral constituents of the waste, releasing accumulated slag and metal, according to the invention, the burning of organic components of municipal solid waste and the melting of their mineral components produce n surface of the molten superheated to 1500-1600 ⁰ C slag produced from added simultaneously with solid municipal waste fluxes and mineral constituents in an atmosphere of oxygen blown combined burners, lances with supersonic velocity, in the melting chamber, the casing which is cooled by a liquid metal coolant, mounted in the mouth energy boiler, which is used for heat recovery of exhaust gases, with drying of municipal solid waste to a moisture content of 5-12% before being fed to the charge loading system villa chamber in the conveyor device, sheltered hermetic casing with nitrogen gas, heated to 150 ⁰ C with heat accumulated by the coolant while cooling the metallic casing of the melting chamber.

In addition, dust trapped in the gas treatment system of a municipal solid waste treatment plant is blown

SUBSTITUTE SHEET (RULE 26) special injectors into the slag melt in the melting chamber, melt and assimilate the slag.

In addition, the composition and properties of slag obtained during the processing of municipal solid waste are adjusted by the addition of technogenic waste from ferrous and non-ferrous metallurgy and the ash of thermal power plants introduced into the melting chamber simultaneously with solid municipal waste.

As additives of industrial wastes of ferrous and non-ferrous metallurgy, waste slag, dust, and sludge are used.

The burning of TKO on the surface of molten, superheated slag, in an atmosphere of pure oxygen, provides much faster combustion of organic waste components, the possibility of burning carbon waste according to the scheme: C + Og ^→ CO ₂ , with the release of a much larger amount of heat in the working chamber, t .to. the thermal effect of the C + O ₂ ^→ CO ₂ reaction is more than 2 times higher than the thermal effect of carbon oxidation reactions in the slag according to the C + 1 / 2O ₂ → СО scheme and, accordingly, the possibility of a significant increase in the temperature of the working space of the chamber and the temperature of the exhaust gases from it.

Due to this, the melting of TKO mineral components and special additives introduced into the slag is accelerated, they completely burn out in the working space of the chamber and the boiler utilizing the heat of the exhaust gases generated during the combustion of waste dioxins and furans, and the thermal efficiency of the installation increases.

The use of combined fuel-oxygen burner-tuyeres makes it easy to start the process by melting the fusible initial primary slag by the working fuel-oxygen

SUBSTITUTE SHEET (RULE 26) burners and going on only to blow oxygen with tuyeres at a supersonic speed.

The supersonic speed of the oxygen stream ensures efficient waste burning and good mixing of the slag, which contributes to its rapid heating and accelerates the assimilation (dissolution) of the mineral components of the waste by the slag.

The proposed cooling of the housing of the MMT allows to obtain a skull on the inner surface of the chamber, limiting the slag volume, and to work without the use of refractory lining of the slag belt. The heat accumulated by the LMC can be used to dry the TKO before loading them into the melting chamber.

The installation of the chamber at the mouth of the boiler allows you to utilize the physical and chemical heat leaving the gas smelting chamber at the lowest cost.

It is also proposed to dry wet TKOs before being fed to the charge system of the melting chamber charge to a moisture content of 5-12%, in a special conveyor device covered with a sealed casing, gaseous nitrogen heated with heat accumulated to 150 ^° C, and accumulated iron and steel, while cooling the casing of the melting chamber.

In this case, when drying wet waste in a neutral atmosphere of nitrogen, the possibility of spontaneous combustion of waste and uncontrolled increase in temperature, the formation of dioxins and furans, as well as their release into the atmosphere, is completely excluded.

TKO pre-drying allows to increase the rate and temperature of their combustion, to reduce the amount of exhaust gases from the melting chamber that require complex, multi-stage purification, and

SUBSTITUTE SHEET (RULE 26) reduce capital and operating costs for gas cleaning accordingly.

In addition, it is proposed to adjust the composition and properties of the slag obtained during the TKO processing by additives of technogenic waste from ferrous and non-ferrous metallurgy (dump slags, dust, sludge, etc.), TPP ash loaded into the melting chamber simultaneously with TKO. This allows you to drain molten, overheated slag from the melting chamber, which in composition and properties are suitable for receiving various commercial products from them after casting: slag stone casting, cement clinker, etc. In addition, the simultaneous loading of waste such as TKO, slag, sludge, ash TPP, reduces the likelihood of the removal of small light fractions of municipal waste from the smelter by a stream of exhaust gases.

Additionally, it is proposed that the dust captured in the gas treatment system be blown with special injectors into the slag melt in the melting chamber, where it is melted and assimilated by the slag. As a result, TKO is completely waste-free and environmentally friendly.

The essence of the claimed method is illustrated by the technological scheme of non-waste processing of solid municipal waste.

The figure shows the technological scheme of non-waste processing of municipal solid waste.

A non-waste method for processing solid municipal waste includes grinding waste in device 1, drying waste in device 2, loading it into the free space 5 of the melting chamber 5, 6, 7. The melting chamber 5,6,7 has a free space 5, space 6 for molten slag and space 7 for molten metal.

SUBSTITUTE SHEET (RULE 26) The organic components of solid municipal waste are burned and their mineral components are melted on the surface of molten slag 6. In the energy boiler 8, afterburning and heat recovery of 5.6.7 gases leaving the free space 5 of the melting chamber are performed. The gases are cleaned in system 9, the dust is collected in the hopper 10. The organic components of solid municipal waste (TKO) are burned and their mineral components are melted on the surface of molten slag 6 overheated to 1500-1600 ⁰ C, obtained from fluxes added simultaneously with solid municipal waste and mineral constituents in an oxygen atmosphere blown by combined tuyere-burners 11 with supersonic speed. The melting chamber 5,6,7 is equipped with a casing (not shown in the figure), cooled by a liquid metal coolant, and installed in the mouth of the energy boiler 8, which is used to recover the heat of the exhaust gases. Drying of municipal solid waste is carried out in the device 2, then in the loading device 3 before feeding the charge system 4 of the melting chamber 5 to humidity

5-12% gaseous nitrogen heated to 15O ⁰ C heat, accumulated metal coolant while cooling the casing of the melting chamber 5,6,7. Conveyor loading device 3, designed to load TKO into the melting chamber 5, is covered by a hermetic casing (not shown in the figure). The dust trapped in the gas purification system 9 is blown into the slag melt 6 by injectors 12, then melted and assimilated by the slag. The melting chamber 5,6,7 in its space 6 for molten slag is equipped with a device 13 for releasing slag, in the space 7 for molten metal has a device 14 for releasing metal.

SUBSTITUTE SHEET (RULE 26) The composition and properties of slag obtained during the processing of municipal solid waste are adjusted by the addition of technogenic waste from ferrous and non-ferrous metallurgy and ashes of thermal power plants introduced into the melting chamber 5,6,7 simultaneously with solid municipal waste.

Examples of specific implementation, confirming the possibility of implementation of the proposed method.

Example 1. The cooling of metal surfaces operating at high temperatures (1600-2300 ° C) LMT has long been effectively used in nuclear power. Therefore, in the conditions of a melting chamber that processes waste according to the proposed method, such a method of cooling a metal casing will also be effective. Example 2. In a laboratory resistance furnace, in a molybdenum crucible, 200 g of slag containing 20% CaO, 50% SiO ₂ , 10% Na ₂ O, 10% FeO, 5% Al ₂ O ₃ , 5 was melted and heated to 1500 ° C. % MgO. The moisture content of the waste before drying was 15%. The working space of the laboratory furnace at a temperature of 150 ° C was filled with nitrogen. On the surface of the slag, in a stream of oxygen, was loaded 800 g of crushed TKO with a moisture content of 10%. The waste is completely burned out. The temperature in the working space of the furnace was 1950 ⁰ C, the mass of slag increased to 350 g, the temperature of the slag at the end of the experiment was 1580 ⁰ C.

Example 3. In a muffle laboratory furnace, the working space of which at a temperature of 150 ° C was filled with nitrogen, loaded 2 kg of crushed TKO with a moisture content of 35%. The moisture content of the waste decreased to 12%, and after holding for 1.5 hours, no ignition of the waste was observed.

Example 4. In a molybdenum crucible, molten 150 g of slag obtained by burning TKO. Then 150 g of dump slag was added to the crucible.

SUBSTITUTE SHEET (RULE 26) nickel production. After melting the additive, a slag was obtained containing 45% SiO ₂ , 15% AI ₂ O ₃ , 15% CaO, 5% MgO ₅ 20% FeO, suitable for the production of slag stone casting. Bibliography.

1. Patent RU 2045703, MKI-6: F23G5 / 00, “Method for the thermal processing of solid waste”, the applicant and owner of CJSC Algon, authors: Usachev A.B., Romenets BA, Grebenshchikov BP, Balasanov AB, Churgel V. ABOUT.

2. Patent RU 2045708, MKI-6: F23G5 / 00, “Method for the processing of solid household wastes”, applicant and owner of the Gintsvetmet, authors: Kalnin E.I., Grechko AB, Mechev BB, Denisov V.F., Shishkina L.D., Ziberov BE, Khaylov E.G., Generalov V.A.

3. Patent RU 2064506, MKI-6: C2IBISUO, F23G5 / 00, “Method for the processing of municipal solid waste in slag smelting”, applicant Rottenberg V. H., Elenina JI. V., they are the authors and owners of the patent.

4. Patent RU 2208202, MKI-7: F23G5 / 00, “Method for the processing of municipal solid waste and fine industrial waste”, applicant of Lipetskstalproekt OJSC, authors and patent holders: A. Reshetnyak, V. A. Konev, Seryakov H.I., Mamaev A.N.

5. Patent RU 2265774, MKI-7: F23G5 / 00, “Method for processing solid household, industrial and medical waste”, authors: Balasanov AB, Batygin SV., Bernadiner MH, Grinberg Yu.M., Devitaykin A.G., Lebedev AB, Teslika I.E., Usachev A.B., Gaykin B.C., patent holder: ZAO BHIIETO, 000 Steelwork Project.

SUBSTITUTE SHEET (RULE 26)

Claims

FORMULA

1. A method of non-waste thermal processing of municipal solid waste, including drying the waste, loading it into the melting chamber, burning organic components, afterburning and cleaning the gases leaving the melting chamber, utilizing the heat of the exhaust gases, melting the mineral constituents of the waste, discharging accumulated slag and metal, characterized the fact that the burning of organic components of municipal solid waste and the melting of their mineral components produce on the surface of the molten superheated to 1500-16 00 ⁰ C of slag obtained from fluxes and mineral components added at the same time as solid municipal waste in an atmosphere of oxygen blown by combined tuyere burners with supersonic speed in a melting chamber, the casing of which is cooled by a liquid metal coolant installed in the mouth of an energy boiler used for recycling heat of exhaust gases, with drying of municipal solid waste to a moisture content of 5-12% before being fed into the loading system of the charge of the melting chamber, in a conveyor device, is covered m hermetic casing with nitrogen gas, heated to 150 ⁰ C with heat accumulated by the coolant while cooling the metallic casing of the melting chamber.

2. The method according to p. 1, characterized in that the dust trapped in the gas treatment system of the unit processing solid municipal waste is injected into the slag melt in the melting chamber by injectors, melted and assimilated by slag.

3. The method according to p. 1, characterized in that the composition and properties of the slag obtained during the processing of municipal solid waste are adjusted by the addition of technogenic waste from the ferrous and non-ferrous metallurgy and ashes of thermal power plants introduced into the melting chamber simultaneously with solid municipal waste.

4. The method according to p. 1, characterized in that as waste additives of ferrous and non-ferrous metallurgy use waste slag, dust, sludge.