JP5495692B2 - Recycling method of waste landfill site - Google Patents

Description

  According to the present invention, it is possible to extend the life of a waste landfill disposal site by reducing the volume of the waste already buried in the waste landfill disposal site and increasing the remaining capacity of the waste landfill disposal site. The present invention relates to a method for reclaiming a waste landfill site used to make it possible.

  The landfill disposal site, also called the final disposal site, is difficult to secure new land, and the remaining years are expected to reach the limit in the near future. Therefore, in order to extend the life of the landfill site, efforts are being made to reduce the amount of waste to be landfilled as a reduction field.

  On the other hand, if the volume of waste already landfilled at the waste landfill site can be reduced, the remaining capacity of the waste landfill site can be increased and the remaining years can be increased. . In view of this point, there is also a need for regeneration of a waste landfill site that increases the residual capacity by reducing the volume of waste landfilled in the waste landfill site.

  Landfills that dispose of general wastes are incinerated ash generated as incineration residue when combustible waste is incinerated in an incinerator, fly ash of incineration residue or processed solidified cement, or incombustible waste Etc. are landfilled as landfill processing objects, and the top is covered with cover soil.

  By the way, plastic waste is combustible, but the amount of heat generated during combustion is high in calories, so the problem of damaging the furnace due to high combustion temperature, the problem of melting and dropping in the furnace, Furthermore, since there is a problem that chlorine-containing plastics, mainly vinyl chloride, generate hydrogen chloride gas, it was previously unsuitable for incineration along with the other landfill treatment objects mentioned above at the landfill site. There were many cases where landfills were disposed of.

  Many of the plastic wastes are containers and films, and the apparent specific gravity is extremely small at around 0.1. Therefore, the landfill capacity is very large, and it remains intact for many years. It has.

  In recent years, with the advancement of incinerators, plastic waste has been incinerated and disposed of. However, as described above, existing waste landfill sites already have The reality is that many plastic wastes are disposed of in landfills.

  In addition, incinerated ash and incombustible waste, which are the objects to be landfilled, contain not only combustible waste other than plastics.

  One of the methods for reclaiming the waste landfill site as described above is to dig up the waste landfilled in the waste landfill site and recycle (recycle) plastic waste, etc. Conceivable.

  However, the plastic waste dug up from the landfill site is covered with the earth and sand derived from the cover soil, the incinerated ash and fly ash that are landfilled together, and has a lot of moisture. Therefore, it is difficult to mechanically sort plastic wastes from other wastes, and therefore, manual sorting and cleaning processes by workers are required, and labor and labor are increased. Recycling plastic waste dug up from a landfill site is not very realistic.

  Therefore, another method for reclaiming the waste landfill site is as described above, considering that plastic waste can be incinerated in the recent advanced incinerators. Waste that has been dug up in the site (waste disposal site) and can be reused in the construction of incombustible waste (incombustible material), inflammable materials with low bulk density, and pollution prevention equipment Then, the bulky combustible material is incinerated with the incineration facility and incineration ash melting facility in operation at the existing incineration plant, and then melted to reduce the volume. Conventionally, a method for reclaiming a waste disposal site that backfills the used waste has been proposed (see, for example, Patent Document 1). According to this method, it is possible to incinerate bulky plastic waste and combustibles other than plastics among the waste landfilled in the waste landfill disposal site, enabling a significant volume reduction. It is considered to be.

  The applicant of the present invention converts the waste material into pyrolysis gas in an external heat kiln type pyrolysis furnace having a heating channel, and burns a part of the pyrolysis gas taken out from the pyrolysis furnace in the hot air generating furnace. A waste pyrolysis gasification apparatus has been proposed in which the combustion gas generated in this way is used as a heat source for thermal decomposition of waste by circulating it through the heating flow path of the external heat kiln furnace (for example, Patent Document 2).

  In addition, the applicant of the present invention converts the waste material into pyrolysis gas by internal heat using the high-temperature gas introduced into the furnace in the pyrolysis furnace, and a part of the pyrolysis gas taken out from the pyrolysis furnace in the combustion furnace. There has also been proposed a waste pyrolysis gasification apparatus in which high-temperature combustion gas generated by combustion is supplied to the pyrolysis furnace as a heat source for thermal decomposition of waste (for example, Patent Document 3). reference).

JP 2000-51810 A JP 2001-82714 A JP-A-10-132240

  However, in the recycling method of the waste disposal site shown in the above-mentioned Patent Document 1, it is possible to incinerate bulky plastic waste and combustible waste other than plastic in the waste dug up from the waste landfill disposal site. Although the volume can be significantly reduced, the following problems arise.

  In other words, if only plastic waste dug up from the waste landfill site and combustible waste other than plastics are incinerated, the amount of heat generated during combustion becomes high calories, so the waste dug up from the waste landfill site An incinerator for reducing the volume (hereinafter referred to as an incinerator for reducing the volume of waste) increases in size. Furthermore, there is a concern that the furnace may be damaged by the high combustion temperature.

  Also, incineration ash and fly ash as incineration residue in old-fashioned incinerators buried in waste landfill sites may contain high concentrations of dioxins, mainly fly ash. high. For this reason, incineration residues that may contain high concentrations of dioxins cannot be separated from plastic waste and combustible waste other than plastics and refilled as they are. It is necessary to supply to the incinerator for gasification and incinerate at a high temperature. At this time, the fly ash contained in the incineration residue dug up is from the incinerator for volume reduction of the waste. It is discharged again as fly ash in the exhaust gas.

  Furthermore, when the earth and sand derived from the excavated plastic waste and the cover soil adhering to combustible waste other than the plastic are supplied to the incinerator for volume reduction of the waste, the earth and sand are discharged into the exhaust gas. Sometimes released as ash.

  Therefore, in the incinerator for reducing the volume of waste, there is a problem that the exhaust gas treatment facility (dust collection facility) increases in size because the concentration of dust in the exhaust gas increases. In addition, the amount of fly ash increases.

  Due to the chlorine (Cl) contained in chlorine-containing plastics such as vinyl chloride, combustion exhaust gas with high hydrogen chloride (HCl) concentration is generated from the incinerator for reducing the volume of waste. An advanced exhaust gas treatment facility capable of treating harmful gases, mainly hydrogen, is required, and this also increases the size of the exhaust gas treatment facility. In addition, although it is conceivable to dry-process the combustion exhaust gas having a high hydrogen chloride concentration with slaked lime, etc., in this case, the amount of fly ash greatly increases, so the amount of fly ash to be refilled is more It will increase.

  Furthermore, fly ash that was generated from an incinerator and landfilled at a landfill site contains low-melting salt. This low-melting salt is used to reduce the volume of waste. When placed in an incinerator, there is a concern that it may melt and gasify during the incineration process and solidify during the cooling process, thereby adhering to the flue and causing blockage. Furthermore, there is a risk of causing severe molten salt corrosion for metals.

  Therefore, the present inventor can reduce the volume of the waste dug up from the waste landfill site to a state close to the case of incineration in the incinerator for volume reduction of the waste, and from the waste landfill site. As a result of repeated efforts and research to solve the above-mentioned problems associated with incineration of excavated waste in an incinerator for volume reduction of waste, the landfill capacity has increased. Paying attention to the fact that most plastic waste that has a large impact on the remaining capacity of the landfill site is volatile, the plastic waste is 850 ° C or higher required for incineration. Pyrolysis treatment at about 400 to 500 ° C., which is significantly lower than the treatment temperature, can be almost gasified and can achieve a significant volume reduction. It was found that the waste excavated from the branch can be reduced to a state close to incineration in an incinerator for volume reduction of waste by subjecting it to thermal decomposition at the specified thermal decomposition temperature. Invented.

  Note that the waste pyrolysis gasification apparatus proposed by the present applicants in Patent Document 2 and Patent Document 3 is treated as waste such as municipal waste, that is, waste containing various combustible materials. However, it does not pay particular attention to the volume reduction rate of plastic waste.

  Therefore, the object of the present invention is to treat waste excavated from a waste landfill site in a simple, low-pollution and efficient manner compared to incineration in an incinerator for volume reduction of waste. In this way, the volume can be reduced to a level close to that of incineration, thereby increasing the remaining capacity of the landfill site and extending the remaining years of the landfill site. In addition, the dust concentration in the exhaust gas can be kept low, and the absolute amount of hydrogen chloride gas (HCl) generated in the exhaust gas can be suppressed, which may increase the size of the exhaust gas treatment facility. It can be avoided, and the exhaust gas does not contain low melting point salt gas, so it is possible to prevent clogging of the flue and molten salt corrosion of the metal part. Landfilled Even if high-concentration dioxins are contained in the incineration residue of old-fashioned incinerators, the dioxins can be decomposed and contribute to the stabilization and detoxification of the entire waste landfill site. Thus, an object of the present invention is to provide a method for reclaiming a waste landfill disposal site that can be expected to have an advantageous effect for preserving the environment of the waste landfill disposal site.

In order to solve the above-mentioned problem, the present invention, corresponding to claim 1, heats the waste dug up from the waste landfill site at a temperature of 400 to 500 ° C. with a thermal decomposition treatment apparatus, and the combustibles in the thermal decomposition treatment in, generates a pyrolysis gas, a pyrolysis residue containing carbides, whereas the combustion of the pyrolysis gas is recovered from the thermal decomposition treatment apparatus, the upper Symbol pyrolysis apparatus It is set as the recycling method of the waste landfill disposal site which recycles the pyrolysis residue containing the carbide | carbonized_material collect | recovered more as a part of a shielding material or covering soil to the said waste landfill disposal site.

In addition, in the above configuration, incineration ash and fly ash in the waste excavated from the waste landfill disposal site is supplied to the thermal decomposition treatment equipment as necessary, and pyrolysis containing the incineration ash and fly ash together with carbides. Make it a residue .

According to the recycling method of the waste landfill disposal site of the present invention, the following excellent effects are exhibited.
(1) The waste dug from waste landfill, by heating at a temperature of 400 to 500 ° C. In the thermal cracking facility by thermally decomposing combustibles in the waste, and pyrolysis gas, carbides generating a thermal decomposition residue containing, while burning the pyrolysis gas is recovered from the thermal decomposition treatment apparatus, the thermal decomposition residue containing carbide is recovered from the above SL pyrolysis apparatus, a shielding material or covered with soil As part of the project, landfill disposal is performed again at the above-mentioned waste landfill site, so plastic waste and combustible waste other than plastic contained in the waste excavated from the waste landfill site are combustible. In this case, plastic waste, which is mostly volatile, can be pyrolyzed and gasified. In addition, combustible waste other than plastics can be pyrolyzed and gasified of volatile matter, so that the volume of waste can be greatly reduced to a state close to incineration by the above pyrolysis treatment. Therefore, since the remaining capacity of the waste landfill site can be increased, the remaining years of the waste landfill site can be increased to extend the life.
(2) Pyrolysis of combustible matter from the waste excavated from the above-mentioned waste landfill site allows the fixed carbon to be converted into stable carbide, and the pyrolysis residue containing this carbide is disposed of in the landfill. By landfilling in the field, CO ₂ emissions can be reduced compared to the case of incineration of the excavated waste. In addition, since the above carbide is charcoal, it is possible to purify the leachate in the waste landfill site by decomposing the pyrolysis residue containing the carbide, to deodorize it, and to absorb harmful heavy metals. Therefore, it can be effectively used to stabilize and detoxify the soil of the entire landfill site. As described above, it is possible to make the waste landfill site advantageous for environmental conservation.
(3) Incineration ash, fly ash, and earth and sand contained in the excavated waste are discharged as pyrolysis residue as they are and do not move to the pyrolysis gas side, so that only pyrolysis gas can be burned. And the dust concentration in the combustion gas treated by the exhaust gas treatment device can be kept low. In addition, when performing pyrolysis with a pyrolysis device, chlorine (Cl) contained in chlorine-containing plastics such as vinyl chloride is included in the residual components in the waste that undergoes pyrolysis. since you are K, it can be Na, is reacted with Ca or the like KCl, NaCl, to shift fixed as inorganic salts CaCl _2, etc., to the pyrolysis residue, are included in the pyrolysis gas and in that the combustion gas is discharged Hydrogen chloride (HCl) concentration can be reduced as compared to incineration. Therefore, it is possible to avoid the possibility that the exhaust gas treatment device will be enlarged.
(4) Furthermore, even if the waste to be pyrolyzed contains low melting point salt derived from incineration ash or fly ash, thermal decomposition at about 400 to 500 ° C. is much lower than the incineration temperature. At temperature, the low melting point salt remains on the pyrolysis residue side and does not migrate to the pyrolysis gas side. Therefore, in the combustion of the pyrolysis gas, melting and gasification of the low melting point salt does not occur, so that it is possible to avoid the risk of flue blockage and molten salt corrosion.
(5) By utilizing the pyrolysis residue containing the carbide as part of the soil covering, an effect of reducing the amount of soil covering can be expected.
(6) Incineration ash and fly ash in the waste excavated from the waste landfill site are supplied to the thermal decomposition treatment equipment, and incinerated by making the pyrolysis residue containing the above incineration ash and fly ash together with carbides. When ash or fly ash contains dioxins, dioxins can be decomposed by the thermal decomposition processing equipment, so thermal decomposition is recovered from the thermal decomposition processing equipment and re-filled at the landfill site. The residue may be dioxins reduced to a reference value or less.

It is a schematic diagram showing one embodiment of a recycling method of a waste landfill disposal site of the present invention. It is a general | schematic cutting side view which shows the thermal decomposition processing apparatus used with the reproduction | regenerating method of FIG.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  1 and 2 show an embodiment of the method for reclaiming a waste landfill site according to the present invention, which is as follows.

  That is, first, in the waste landfill disposal site 1, the waste 2 that has been landfilled is removed after the covering soil is removed by using an unillustrated excavator such as an excavator excavator. At this time, earth and sand derived from the covering soil or the like may be mixed in the excavated waste 2.

  Next, the waste 2 dug up as described above is transported by a transport means (not shown) such as a belt conveyor, and supplied to the thermal decomposition apparatus 8. At this time, plastic waste 3 contained in the excavated waste 2, incombustible waste (incombustible material) 4, incineration ash 5, fly ash 6, and combustible materials other than plastics mixed in these Of the waste 7, at least the plastic waste 3 and combustible waste 7 other than plastic are supplied to the thermal decomposition apparatus 8. In addition, the plastics such as non-burnable garbage 4, incinerated ash 5 and fly ash 6 in the excavated waste 2 are attached to the plastic waste 3 and combustible garbage 7 other than plastics. Those that cannot be easily separated from the combustible waste 7 other than the waste 3 and plastics may be supplied together to the thermal decomposition treatment apparatus 8. Further, if the incinerated ash 5 or fly ash 6 in the excavated waste 2 contains or may contain a high concentration of dioxins, it may or may contain the high concentration of dioxins. Incinerated ash 5 and fly ash 6 are supplied to the thermal decomposition treatment device 8.

  The non-combustible waste 4 in the excavated waste 2 and the incinerated ash 5 and fly ash 6 that may not contain dioxins are easily combined with the plastic waste 3 and combustible waste 7 other than plastics. Those that are separable may be refilled as they are in the waste landfill disposal site 1 at a required timing such as when the thermal decomposition residue 16 is refilled later.

  Next, in the thermal decomposition treatment apparatus 8, the plastic waste 3 and the combustible waste 7 other than plastic among the waste 2 dug up, and the non-combustible waste 4 attached to them, the incineration ash 5, and the fly ash 6 and waste 2a containing thermal incineration ash 5 or fly ash 6 containing or possibly containing high-concentration dioxins are generated by leaking into oxygen-free or thermal decomposition processing device 8 Heat to about 400 to 500 ° C. in a low oxygen atmosphere of 3% or less to thermally decompose the combustible component.

  Specifically, as shown in FIG. 2, for example, the pyrolysis apparatus 8 is a rotary kiln that is disposed laterally at a required angle so that the outlet 9b at the other end is lower than the inlet 9a at the other end. A dust feeder 10 is provided on the inlet 9a side at one end in the longitudinal direction of the furnace 9, and the feeder hopper 11 has a charging hopper 11 for receiving the pyrolysis target waste 2a transported by the transport means (not shown). The pyrolysis gas 15 and the pyrolysis residue 16 are separated from the bottom end and connected to the outlet 9b at the other end in the longitudinal direction, and taken out from the top gas outlet 13 and the bottom residue outlet 14, respectively. A separation chamber 12 is provided, and further, high-temperature combustion that is generated in a pyrolysis gas combustion furnace 18 to be described later and guided through a combustion gas line 19 in a heating flow path 17 provided outside the kiln furnace 9. The scan 20, to the outlet 9b side of the kiln furnace 9 a structure in which to be able to be distributed toward the inlet 9a side.

  Further, the pyrolysis gas combustion furnace 18 is connected to the gas outlet 13 of the separation chamber 12 of the pyrolysis apparatus 8 via a pyrolysis gas line 21, and the pyrolysis gas combustion furnace 18 is connected to the pyrolysis gas combustion furnace 18. The pyrolysis gas 15 generated in the pyrolysis processor 8 is guided and burned.

  On the other hand, the residue outlet 14 of the separation chamber 12 of the thermal decomposition treatment apparatus 8 is connected to a water tank 23 via a residue extraction pipe 22, and the thermal decomposition residue 16 generated in the thermal decomposition treatment apparatus 8 is transferred to the water tank 23. Once it is put in and cooled, it can be recovered outside by required recovery means (not shown).

  Reference numeral 24 denotes a branch line branched from a midway position of the combustion gas line 19 connecting the pyrolysis gas combustion furnace 18 and the heating flow path 17 of the pyrolysis processor 8, and 25 denotes a flow path through the heating flow path 17. It is a combustion gas discharge line which takes out the combustion gas 20 after this. The downstream sides of the branch line 24 and the combustion gas discharge line 25 are both connected to an exhaust gas treatment device 26 and used as a heat source for heating the thermal decomposition target waste 2a in the thermal decomposition treatment device 8. Both the surplus of the combustion gas 20 and the combustion gas 20 after flowing through the heating flow path 17 of the pyrolysis treatment device 8 and being used as a heat source for heating the waste 2a to be pyrolyzed are used in the exhaust gas treatment device. It is made to be able to discharge | release, after sending to 26 and performing a required exhaust gas treatment.

  When the pyrolysis apparatus 8 having the above configuration is used, the pyrolysis target waste 2a in the charging hopper 11 is kiln by the dust feeder 10 while the kiln furnace 9 is rotated at a low speed. While supplying into the furnace 9, a high-temperature combustion gas 20 led from the pyrolysis gas combustion furnace 18 through the combustion gas line 19 is circulated in the heating flow path 17 outside the kiln furnace 9, and the kiln furnace 9. The waste 2a to be pyrolyzed is indirectly heated to about 400 to 500 ° C. by external heat to pyrolyze the combustible component, and the fixed carbon component in the combustible component is converted to solid carbide (char) 27. On the other hand, the volatile matter is converted into a pyrolysis gas 15.

  Thereafter, the pyrolysis gas 15 generated by the pyrolysis treatment of the combustible component of the pyrolysis target waste 2a is led from the gas outlet 13 of the separation chamber 12 to the pyrolysis gas combustion furnace 18 through the pyrolysis gas line 21. By burning, it is used to generate the combustion gas 20 as a heat source for heating the waste 2a to be pyrolyzed in the kiln furnace 9.

  On the other hand, the carbide 27 generated by the pyrolysis treatment of the combustible component 2a of the thermal decomposition target waste 2a is heated together with the incombustible waste 4, the incinerated ash 5 and the fly ash 6 contained in the thermal decomposition target subject 2a. Since it becomes the decomposition residual 16, it guides to the water tank 23 through the residue extraction pipe | tube 22 from the residue extraction opening 14 of the bottom part of the said separation chamber 12, and it collects after cooling in this water tank 23.

  Thereafter, as shown in FIG. 1, the pyrolysis residue 16 containing the carbide 27 is landfilled again in the waste landfill 1 where the waste 2 has been dug up. Under the present circumstances, the carbide | carbonized_material 27 contained in the said thermal decomposition residue 16 is charcoal, and is effective in purifying water and deodorizing, and can also anticipate the effect which prevents elution of heavy metal. Therefore, the pyrolysis residue 16 containing the carbide 27 is buried as a covering material 28 for other landfills, or is mixed as a part of the cover soil 30 as charcoal 29 for covering soil, and is disposed as a waste landfill disposal site. It may be made to fill in one. Although not shown, the pyrolysis residue 16 containing the carbide 27 may be simply landfilled in the waste landfill disposal site 1.

  Various facilities such as the thermal decomposition treatment device 8 for performing the thermal decomposition treatment of the waste 2 dug up from the waste landfill disposal site 1 and the exhaust gas treatment device 26 attached thereto, excavate the waste 2. It is preferable to install in the waste landfill site 1 to be performed.

  Further, as shown in FIG. 1, incombustibles and fly ash 31 generated in the exhaust gas treatment process in the exhaust gas treatment device 26 are supplied again to the thermal decomposition treatment device 8, or although not shown, the carbide 27 It may be mixed with the pyrolysis residue 16 containing, and landfilled at the waste landfill site 1.

  Thus, according to the recycling method of the waste landfill disposal site of the present invention, plastic waste 3 contained in the waste 2 dug up from the waste landfill disposal site 1 and combustible waste 7 other than plastics 7 Can be pyrolyzed as a combustible component. At this time, most of plastic waste 3 which has many containers and films, has a very small apparent specific gravity, and has a very large landfill capacity, is mostly volatile matter. Thus, the pyrolysis gas 15 can be obtained. Further, combustible waste 7 other than plastics can also be converted into pyrolysis gas 15 from its volatile matter. Thereby, about the waste 2 dug up from the waste landfill disposal site 1, the volume can be significantly reduced to a state close to incineration.

  Therefore, since the remaining capacity of the waste landfill site 1 can be increased, the remaining years of the waste landfill site 1 can be increased to extend the life.

Furthermore, the fixed carbon content in the waste 2 can be made into a stable carbide 27 by thermal decomposition of the combustible waste in the waste 2 dug up from the waste landfill disposal site. By reclaiming the pyrolysis residue 16 in the same waste landfill site 1 again, it is possible to reduce the amount of CO ₂ emission as compared with the case where the incinerated waste 2 is incinerated.

  Further, since the carbide 27 is charcoal, the waste water (leachate) in the waste landfill 1 is purified by the carbide 27 by performing landfill disposal of the pyrolysis residue 16 containing the carbide 27. Since it can deodorize and adsorb toxic heavy metals, it can be effectively used to stabilize and detoxify the soil of the waste landfill site 1 as a whole.

  Moreover, since the incinerated ash 5 and fly ash 6 containing dioxins can be decomposed by heating them in an oxygen-free or low-oxygen atmosphere in the thermal decomposition treatment device 8, the thermal decomposition treatment device 8 described above. The pyrolysis residue 16 that is further recovered and landfilled again in the waste landfill site 1 can have dioxins reduced to a reference value or less.

  As described above, the recycling method of the waste landfill disposal site according to the present invention can be advantageous for environmental protection of the waste landfill disposal site 1.

  Furthermore, since the incinerated ash 5, fly ash 6 and earth and sand contained in the thermal decomposition target waste 2a supplied to the thermal decomposition processing device 8 are separated from the thermal decomposition gas 15 as the thermal decomposition residue 16, It is not contained in the combustion gas 20 discharged from the pyrolysis gas combustion furnace 18 for burning the pyrolysis gas 15. Therefore, the dust concentration in the combustion gas 20 processed by the exhaust gas processing device 26 can be kept low.

In addition, when the thermal decomposition treatment target waste 2a is thermally decomposed by the thermal decomposition processing device 8, chlorine (Cl) contained in chlorine-containing plastics such as vinyl chloride in the plastic waste 3 is K contained in residue component (ash component) of the thermal decomposition processed waste 2a a part, Na, is reacted with Ca or the like KCl, NaCl, and fixed as inorganic salts CaCl ₂ such as thermal The decomposition residue 16 can be transferred. Therefore, the concentration of hydrogen chloride (HCl) contained in the combustion gas 20 discharged from the pyrolysis gas combustion furnace 18 that burns the pyrolysis gas 15 can be reduced as compared with the incineration process.

  Therefore, it becomes possible to avoid the possibility that the exhaust gas treatment device will be enlarged.

  Furthermore, even if the pyrolysis target waste 2a that undergoes the pyrolysis process in the pyrolysis apparatus 8 contains low melting point salt derived from the incineration ash 5 or the fly ash 6, it is higher than the incineration process temperature. At a pyrolysis temperature of about 400 to 500 ° C., which is significantly low, the low melting point salt remains on the pyrolysis residue 16 side and does not migrate to the pyrolysis gas 15 side. Therefore, when the pyrolysis gas 15 is burned, the low melting point salt is not melted or gasified, so that it is possible to avoid the risk of flue blockage or molten salt corrosion.

  By utilizing the pyrolysis residue 16 containing the carbide 27 as a part of the covering soil 30, an effect of reducing the covering amount can be expected.

  In addition, this invention is not limited only to the said embodiment, The thermal decomposition processing apparatus 8 is the plastic waste 3 contained in the waste 2 dug up from the waste landfill disposal site 1, and If the pyrolysis target waste 2a containing combustible waste 7 other than plastics is heated to about 400 to 500 ° C. in an oxygen-free or low-oxygen atmosphere, the combustible component can be pyrolyzed, As shown in Patent Document 3, waste is pyrolyzed and gasified by internal heat using high-temperature gas introduced into the furnace in the pyrolysis furnace, or pyrolysis in a pyrolysis furnace in a low oxygen atmosphere. Any type of thermal decomposition treatment apparatus 8 such as a partial combustion type that partially burns a part of the waste 2a to be treated and thermally decomposes the remaining part of the waste 2a to be thermally decomposed by the combustion heat is used. May be. The heat source for pyrolysis is preferably of a type that can be self-supplied by combustion of pyrolysis gas, but it may be a pyrolysis apparatus 8 that uses an external heat source.

  The exhaust heat of the combustion gas 20 discharged from the pyrolysis gas combustion furnace 18 through the branch line 24 of the combustion gas line 19 may be recovered by an air preheating device, a boiler, a hot water generator, or the like.

  Of course, various modifications can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Waste landfill disposal site 2 Waste 2a Waste subject to thermal decomposition 5 Incinerated ash 6 Fly ash 8 Pyrolysis treatment device 15 Pyrolysis gas 16 Pyrolysis residue 27 Carbide

Claims (2)

Heat including waste dug from waste landfill, by heating at a temperature of 400 to 500 ° C. at pyrolysis processing apparatus combustible matter in the waste pyrolysis process, the pyrolysis gas, a carbide generating a decomposition residue, while burning the pyrolysis gas is recovered from the thermal decomposition treatment apparatus, the thermal decomposition residue containing carbide is recovered from the above SL thermal cracking facility as part of the shielding material or covered with soil A method for reclaiming a waste landfill site, wherein the landfill site is disposed of again at the waste landfill site. The incinerated ash and fly ash in the waste excavated from the waste landfill site are supplied to a thermal decomposition treatment apparatus so as to obtain a pyrolysis residue containing the incinerated ash and fly ash together with carbides. To recycle waste landfills.

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