JP6276723B2 - Hazardous polystyrene foam waste disposal method and hazardous foam polystyrene waste disposal equipment - Google Patents

Description

  The present invention relates to a harmful foamed polystyrene waste treatment method and a harmful foamed polystyrene waste treatment apparatus for detoxifying harmful foamed polystyrene waste.

  Currently, the shortage of waste disposal sites is becoming prominent, and most of industrial waste and general waste are in landfills after being incinerated or reduced in volume as they are generated or after some pretreatment. Often, final disposal is performed. There are various methods for the incineration treatment described above. In recent years, management of harmful substances such as dioxins in the gas generated in the incineration plant has become a problem. For example, if the waste is treated while being generated, dioxins as harmful substances are generated by being brought into a high-temperature oxidizing atmosphere in the furnace for incineration. Therefore, there is a demand for a treatment method that prevents the dioxins from being discharged outside the furnace by decomposing the dioxins in a high-temperature atmosphere inside the furnace. As a waste treatment method capable of such high temperature treatment, for example, a waste treatment method disclosed in Patent Document 1 can be cited. In the process disclosed in Patent Document 1, in order to perform such processing at a high speed, the waste is compression-molded to form a compressed block to reduce the volume, and then the compressed block is dried and gasified and modified. It is a waste treatment process that is charged into a smelting furnace and pyrolyzed, gasified and gas reformed to melt incombustibles and ash to obtain fuel gas, slag and metal. This waste treatment method is considered to be a highly versatile method because industrial waste and general waste generated in various forms are processed by compression molding batchwise with a compressor.

  By the way, in recent years, from the viewpoint of energy saving and the like, the amount of foamed polystyrene insulation material excellent in heat insulation and heat insulation has been increased. For example, it is used as a building material or a tatami flooring. is necessary. The foamed polystyrene heat insulating material often contains hexabromocyclododecane (HBCD), which is a kind of brominated flame retardant, as a flame retardant for resin. Since the HBCD is difficult to be decomposed in nature and easily accumulated in the body of living organisms, there is a concern that some animals have long-term toxicity. Therefore, the persistence held from April to May 2013 It was added to Annex A (Abolition) of the POPs Convention at the 6th Conference of the Parties to the Stockholm Convention on Organic Pollutants (POPs Convention). In Japan, it is designated as a Class I Specified Chemical Substance in the Law Concerning the Examination of Chemical Substances and Production Regulations (Chemical Substance Control Law) (Promulgation: March 19, 2014). And the regulation with respect to the product containing HBCD comes to be performed, and processing of the waste of the product containing HBCD is also the object of regulation.

Hazardous waste containing HBCD includes waste of foamed polystyrene heat insulating material for construction, and examples include waste material generated during construction, heat insulating material waste generated when building is demolished, and tatami waste material. Regarding a method for treating hazardous waste containing such HBCD, it has been studied to heat HBCD at a high temperature and decompose it to make it harmless. Moreover, the waste of the foamed polystyrene heat insulating material for construction has a bulk density of 50 kg / m ³ or less, and is bulky, so that its processing efficiency is low. For example, as one of the processing methods for the expanded polystyrene material, a processing method as in Patent Document 2 is known. In Patent Document 2, the block-shaped foamed polystyrene material was pulverized by a pulverization mechanism, then supplied to an oilification tank storing a high boiling point catalyst, and the foamed polystyrene material was heated and melted by a heater in the oilification tank. A processing method is disclosed in which a foamed polystyrene melt is further evaporated by heating and gasified to be recovered as a fuel gas. Further, surplus gas generated in the heating and melting process is combusted and exhausted by a surplus gas combustor provided in the oilification tank.

JP-A-6-79252 JP 2000-079379

  However, if a harmful foamed polystyrene waste containing HBCD is treated by the treatment method of Patent Document 2 to decompose and detoxify HBCD, as described above, Patent Document 2 discloses a harmful foam containing HBCD. When decomposing and detoxifying HBCD by treating polystyrene waste, it is necessary to perform pretreatment to pulverize and heat-melt the expanded polystyrene material to obtain a melt, which complicates the process. In this pretreatment, it is necessary to prepare a pulverizing mechanism, a heater, a surplus gas combustor, etc., and there is a problem that the equipment cost and the operating cost increase.

  In view of such circumstances, the present invention provides a harmful foamed polystyrene waste treatment method and a harmful foamed polystyrene waste treatment apparatus that thermally decomposes and detoxifies harmful foamed polystyrene waste without requiring a complicated process. This is the issue.

  According to the present invention, the above-mentioned problems are solved by the following first invention with respect to the harmful foamed polystyrene waste treatment method and by the following second invention with respect to the harmful foamed polystyrene waste treatment apparatus.

<First invention>
In the first invention, in the hazardous foam polystyrene waste processing method of detoxifying the harmful foamed polystyrene waste by a gasification reforming melting furnace, a dissolving step of dissolving the harmful foamed polystyrene waste in a solvent to generate a solution, A compression process in which blocks are formed by compression molding other wastes, and a solution is supplied to the pyrolysis section of the gasification reforming melting furnace together with the block for thermal decomposition and gasification, and gas reforming is performed in the gas reforming section. And a gasification reforming and melting step of melting and discharging the pyrolysis residue and the incombustible material. In the present invention, examples of other waste with respect to hazardous foamed polystyrene waste include general waste and industrial waste.

  In the first invention, a solution produced by dissolving harmful foamed polystyrene waste in a solvent is supplied to the pyrolysis section of the gasification reforming melting furnace together with a block obtained by compression molding the other waste. Then, HBCD, which is a harmful substance contained in the solution, is pyrolyzed together with the other waste in the thermal decomposition section. Thus, HBCD is detoxified by thermal decomposition. In the first invention, the pretreatment of the hazardous foamed polystyrene waste prior to thermal decomposition and gasification of the hazardous foamed polystyrene waste is performed only by the generation of a solution, that is, the dissolution of the expanded polystyrene waste by a solvent. There is no need for a complicated process as in the prior art.

  In the first invention, the melting step may be performed at a location different from the installation location of the gasification reforming melting furnace. In this case, the dissolving step may be performed at a place where the harmful foamed polystyrene waste is generated or at a transportation destination where the harmful foamed polystyrene waste is transported from the place of occurrence.

  The solvent may be any of limonene, cyclohexane, benzene, toluene, ethyl acetate, recovered oil recovered from a coke oven, or waste oil.

<Second invention>
In the second invention, in a harmful foamed polystyrene waste treatment apparatus for detoxifying harmful foamed polystyrene waste, a gasification reforming melting furnace having a thermal decomposition part, a gas reforming part and a melting part, and other wastes A block compression supply device for forming a block by compression molding and supplying the block to the thermal decomposition section of the gasification reforming melting furnace, and a solution generated by dissolving harmful foamed polystyrene waste in a solvent as a gas A solution supply device for supplying to the thermal decomposition section of the gasification reforming melting furnace, the thermal decomposition section of the gasification reforming melting furnace thermally decomposes the block and the solution, and the gas reforming section is gasified gas The melting part is characterized by melting the pyrolysis residue and incombustible material.

  In the present invention, a solution produced by dissolving harmful foamed polystyrene waste in a solvent is supplied to the pyrolysis section of the gasification reforming melting furnace together with a block obtained by compression molding other waste, HBCD, which is a harmful substance contained in the solution, is thermally decomposed in the thermal decomposition part together with the other waste. Therefore, the pretreatment of the hazardous foamed polystyrene waste performed prior to the thermal decomposition and gasification of the hazardous foamed polystyrene waste is only the production of a solution, that is, the dissolution of the foamed polystyrene waste by the solvent. As a conventional process is not required, an increase in equipment cost and operation cost can be suppressed. Moreover, since the solution produced by dissolving the harmful foamed polystyrene waste in the solvent is supplied to the gasification reforming melting furnace, the bulky harmful foamed polystyrene waste can be efficiently detoxified.

It is a figure which shows the structure of the harmful foamed polystyrene waste processing apparatus (henceforth a "processing apparatus" only) based on embodiment of this invention.

  FIG. 1 is a diagram showing a configuration of a hazardous foamed polystyrene waste treatment apparatus according to this embodiment. Before describing a specific configuration of the processing apparatus, first, an outline of processing of harmful foamed polystyrene waste by the processing apparatus will be described.

  The treatment device is a device for detoxifying harmful foamed polystyrene waste. The processing device dissolves harmful foamed polystyrene waste with a solvent to produce a solution, while other waste is compressed batchwise with a block compression feeder to form a compressed block. . Other waste contains fixed carbon (carbon that does not volatilize when heated). And the said melt is supplied to the thermal decomposition part of a gasification reforming melting furnace with the said compression block. In the pyrolysis section, an oxygen-containing gas is introduced, and the compression block and the solution are pyrolyzed and gasified into carbon monoxide, hydrogen, and the like.

  In addition, an oxygen-containing gas is introduced in the gas reforming section of the gasification reforming melting furnace, the gas generated in the thermal decomposition section is gas reformed, and the reformed gas is washed and purified by a gas purifier. Recover as fuel gas. Further, in the melting part, the incombustible material and the ash content of the compression block, the above-described solution are melted and discharged as molten slag and molten metal.

  Hereinafter, the configuration of the processing apparatus 1 will be described with reference to FIG.

  As shown in FIG. 1, the processing apparatus 1 is charged with other waste containing fixed carbon from above in a block compression supply apparatus 20 (hereinafter simply referred to as “compression supply apparatus 20”). A waste input device 10 is provided. The waste input device 10 includes a hopper 11 that receives and stores other waste from the outside, and a lid 12 that forms the bottom of the hopper 11 and can be opened and closed. The waste input device 10 inputs other waste into the compression supply device 20 when the lid 12 is in the open position.

  Below the waste input device 10, there is provided a compression supply device 20 for compressing the other waste and forming a compression block. The compression supply device 20 includes a cylindrical portion 21 that extends horizontally at a position below the hopper 11, a compression head 22 that reciprocates in the cylindrical portion 21 in the front-rear direction (left-right direction in FIG. 1), It has a plate-like compression support plate 23 that reciprocates in the vertical direction at a position downstream of the hopper 11 (right side in FIG. 1) to open and close the downstream opening of the tubular portion 21. The cylindrical portion 21 has an inner wall section having the same shape and the same dimension as an inner wall section of a heating furnace 30 described later.

  In the compression supply device 20, the compression head 22 moves forward (to the right) toward the compression support plate 23 in a state where the compression support plate 23 closes the downstream opening of the cylindrical portion 21 at the lowered position. Thus, the other waste introduced from the hopper 11 is compressed between the compression head 22 and the compression support board 23 in the front-rear direction, and the compression block P of the other waste is formed. The compression block P is formed batchwise. In addition, the compression supply device 20 sequentially forms the compression blocks P so that the compression blocks P are pushed forward and supplied to the thermal decomposition section of the gasification reforming melting furnace 50 through the heating furnace 30.

  A tunnel-type heating furnace 30 (hereinafter referred to as “heating furnace 30”) connected to the cylindrical portion 21 of the compression supply apparatus 20 is provided on the downstream side of the compression supply apparatus 20 so as to extend in the horizontal direction. The heating furnace 30 is heated from the outside, and the compression block P supplied from the compression supply device 20 is dried in the heating furnace 30. The downstream end portion of the heating furnace 30 is connected to the charging port 51 of the gasification reforming melting furnace 50, and the compression block P can be supplied from the charging port 51 into the gasification reforming melting furnace 50. ing.

  Further, the processing apparatus 1 is provided with a solution supply device 40 for supplying a solution containing HBCD, which is produced by dissolving harmful foamed polystyrene waste in a solvent, into the gasification reforming melting furnace 50. ing. The solution supply apparatus 40 includes a tank 41 that stores the solution and a pump 42 that supplies the solution from the tank 41. In the present embodiment, the solution is sent by the pump 42 to a position before the inlet 51 of the gasification reforming melting furnace 50. As will be described later, the sent solution is supplied into the gasification reforming melting furnace 50 together with the compression block P.

  Examples of the solvent used in the dissolving liquid generation step, that is, the dissolving step of harmful foamed polystyrene waste include, for example, limonene, cyclohexane, benzene, toluene, ethyl acetate, recovered oil or waste oil recovered from a coke oven, and the like. It is done. The melting step may be performed at the same location as the installation location (site) of the processing apparatus 1 or may be performed at a location different from the installation location. When the dissolution process is performed at a location different from the installation location, the dissolution process is performed, for example, at the location where the hazardous foamed polystyrene waste is generated or at the transport destination where the hazardous polystyrene foam waste is transported from the location. It may be.

  The gasification reforming melting furnace 50 has a vertical portion extending in the vertical direction and a horizontal portion extending in the horizontal direction from the lower portion of the vertical portion. The portion extending in the vertical direction has a substantially lower half portion formed as a thermal decomposition portion 52 and a substantially upper half portion formed as a gas reforming portion 53. Further, the horizontal portion is formed as a melting portion 54.

  In the thermal decomposition part 52, the compressed block P is deposited to form a waste accumulation layer Q, and the waste and the solution in the waste accumulation layer Q are gasified by thermal decomposition, and incombustible matter and ash are removed. It is supposed to be melted. A first oxygen-containing gas supply port 55 for supplying an oxygen-containing gas into the waste accumulation layer Q is provided at the lower part of the side wall of the gasification reforming melting furnace 50.

  In the gas reforming unit 53, as will be described later, the gas generated from the waste accumulation layer Q in the thermal decomposition unit 52 is reformed to generate a reformed gas. A plurality of second oxygen-containing gas supply ports 56 for supplying an oxygen-containing gas into the gas reforming section 53 are provided on the upper side of the side wall of the gasification reforming melting furnace 50.

  In the melting part 54, the melt generated in the thermal decomposition part 52 is heated, and carbon and the like contained in the melt are gasified and removed. On the upper wall of the horizontal portion of the gasification reforming melting furnace 50, there is provided a fuel gas supply port 57 for supplying fuel gas to the melting portion 54 and heating the melt by combustion heat. Further, a melt discharge port 58 for discharging the melt to the outside is provided in the melt section 54 so as to extend downward.

  A gas duct 60 is provided at the top of the gasification reforming melting furnace 50 to extend from the reformed gas discharge port 59 formed at the top to discharge the reformed gas generated in the gas reforming unit 53 to the outside of the furnace. It has been. On the downstream side of the gas duct 60, a cooling and cleaning device (not shown) that is formed as a separate device from the processing device 1 and cools the reformed gas and performs acid cleaning and alkali cleaning, and a modified device that has been cooled and cleaned. A desulfurization treatment apparatus (not shown) for performing desulfurization treatment on the gas and a gas purification apparatus (not shown) for dehumidifying the reformed gas are provided. Thus, the reformed gas is washed, desulfurized and purified, and can be used as a fuel gas.

  Hereinafter, processing of the harmful foamed polystyrene waste by the processing apparatus 1 will be described.

  First, other waste containing fixed carbon is stored in the hopper 11 of the waste input device 10. Then, the lid 12 provided in the hopper 11 is opened, and a predetermined amount of other waste is put into the compression supply device 20. The compression supply device 20 compresses the waste to form a dense compression block P by moving the compression head 22 forward with the compression support plate 23 brought to the lowered position. The compression block P is formed batchwise. By sequentially forming the compression blocks P, the compression blocks P are pushed forward and supplied to the heating furnace 30.

  The cross-sectional shape of the compression block P is the same shape and the same size as the cross section of the inner wall of the inlet of the heating furnace 30, and the compression block P is pushed into contact with the inner wall of the heating furnace 30. Can seal the atmosphere in the furnace. Each time a new compression block is pushed in, the compression block P moves toward the inlet 51 of the gasification reforming melting furnace 50 while sliding in the heating furnace 30.

  As described above, the heating furnace 30 is heated from the outside, the inside is heated, and the moisture in the compression block P is evaporated and dried in the process of moving and raising the temperature of the compression block P. In addition, the solution is sent from a tank 41 storing a solution containing HBCD to a position before the inlet 51 of the gasification reforming melting furnace 50 by a pump 42. The dried compressed block P and the solution are charged and supplied from the charging port 51 of the gasification reforming melting furnace 50 into the thermal decomposition section 52 of the gasification reforming melting furnace 50.

  The compressed block P supplied into the thermal decomposition unit 52 forms a waste accumulation layer Q. In the waste accumulation layer Q, an oxygen-containing gas is supplied into the waste accumulation layer Q from a first oxygen-containing gas supply port 55 provided in the lower part of the thermal decomposition unit 52. As a result, combustibles such as fixed carbon in other wastes burn, and the wastes and the solution are thermally decomposed by the thermal energy. By this thermal decomposition, gasification to carbon monoxide, hydrogen, hydrocarbons, carbon dioxide, etc. is performed, and further gas reforming is performed, and other wastes and incombustible components (metals, etc.) in the above-mentioned dissolved solution, The ash melts to produce a melt. The reformed gas is washed, desulfurized and purified, and can be used as a fuel gas. The gas component generated by the thermal decomposition of the polystyrene component and the solvent component of the harmful foamed polystyrene waste contained in the solution is also modified and made available as a part of the fuel gas.

  Further, in the melting part 54 connected to the lower part of the thermal decomposition part 52, the melt is heated by the high-temperature combustion gas generated by combustion of the fuel gas supplied from the fuel gas supply port 57, and is contained in the melt. A small amount of carbon is removed by gasification, and the melt is discharged from the melt outlet 58 as molten slag and molten metal.

  In the gas reforming unit 53 of the gasification reforming melting furnace 50, the oxygen-containing gas is supplied from the second oxygen-containing gas supply port 56, and a part of the generated gas from the waste accumulation layer Q is combusted to a temperature. The generated gas is retained in a region where the atmosphere is set to 1000 ° C. or higher, and the following gas reforming is performed.

In the waste accumulation layer Q of the thermal decomposition unit 52, hydrocarbons (methane and the like) and carbon monoxide contained in the generated gas generated by the thermal decomposition of the compressed block P and the solution are the gas reforming unit. In 53, it reacts with the water vapor contained in the generated gas by the reactions (1) and (2) below, and is reformed to contain a large amount of carbon monoxide and hydrogen useful as fuel gas.
CH ₄ + H ₂ O → CO + 3H ₂ (1)
CO + H ₂ O → H ₂ + CO ₂ (2)

  Further, the generated gas from the waste accumulation layer Q is retained in the gas reforming unit 53 in a region where the gas temperature is set to 1000 ° C. or higher, and cracking of tar contained in the generated gas is performed. Tar cracking means that the high molecular weight component of the tar is thermally decomposed into low molecular weight hydrocarbons or carbon monoxide, and when the reformed gas is used as fuel gas by removing the tar content. Troubles caused by tar can be avoided. Further, the hydrocarbon generated by cracking further reacts with steam to be reformed into carbon monoxide and hydrogen useful as fuel gas.

  The reformed gas generated in the gas reforming section 53 is discharged from the reformed gas discharge port 59 at the top of the gasification reforming melting furnace 50 to the gas duct 60 and cooled by a cooling and cleaning device (not shown). At the same time, acid cleaning and alkali cleaning are performed, desulfurization processing is performed by a desulfurization processing apparatus (not shown), dehumidification is performed by a gas purification apparatus (not shown), and the fuel gas can be used.

  As other waste containing fixed carbon, it is preferable to use one having a weight ratio of fixed carbon in the waste of 3% by weight or more. This is because the amount of thermal energy generated by burning the fixed carbon in the other wastes with the oxygen-containing gas in the thermal decomposition unit 52 can be set to an amount sufficient to thermally decompose the solution. In addition, by using a fixed carbon having a weight ratio of 5% by weight or more in other wastes, a sufficient amount of thermal energy is obtained to thermally decompose the solution and to thermally decompose other wastes. This is more preferable.

  If the oxygen-containing gas supplied to the pyrolysis section 52 and the gas reforming section 53 has a large amount of components such as nitrogen other than oxygen, the amount of nitrogen is included in the fuel gas as it is, and the properties as the fuel gas are lowered. Therefore, it is preferable that the oxygen-containing gas to be supplied has a high concentration with an oxygen concentration of 80% by volume or more.

  As described above, in the present embodiment, the solution is supplied to the thermal decomposition section 52 of the gasification reforming melting furnace 50 together with the compression block P obtained by compression molding other waste, and the solution is supplied to the solution. The HBCD, which is a harmful substance contained, is thermally decomposed and made harmless together with the other waste by the thermal decomposition unit 52. Therefore, the pretreatment of the hazardous foamed polystyrene waste performed prior to the thermal decomposition and gasification of the hazardous foamed polystyrene waste is only the production of a solution, that is, the dissolution of the foamed polystyrene waste by the solvent. As a conventional process is not required, an increase in equipment cost and operation cost can be suppressed.

DESCRIPTION OF SYMBOLS 1 Processing apparatus 20 Block compression supply apparatus 40 Solution supply apparatus 50 Gasification reforming melting furnace 52 Thermal decomposition part 54 Melting part

Claims (5)

In the hazardous foam polystyrene waste processing method of detoxifying the hazardous foam polystyrene waste by the gasification reforming melting furnace,
A dissolving step of dissolving harmful polystyrene foam waste in a solvent to produce a solution,
A compression process in which other wastes are compression molded to form blocks;
Gasification reforming that supplies the solution together with the block to the pyrolysis section of the gasification reforming melting furnace, pyrolyzes and gasifies, gas reforms in the gas reforming section, melts and discharges the pyrolysis residue and incombustibles A hazardous foamed polystyrene waste treatment method comprising: a melting step.   The hazardous foaming polystyrene waste disposal method according to claim 1, wherein the melting step is performed at a place different from a place where the gasification reforming melting furnace is installed.   The method for treating hazardous foamed polystyrene waste according to claim 2, wherein the dissolving step is performed at a place where the harmful foamed polystyrene waste is generated or at a transportation destination where the harmful foamed polystyrene waste is transported from the place of occurrence.   The harmful foam according to any one of claims 1 to 3, wherein the solvent is any one of limonene, cyclohexane, benzene, toluene, ethyl acetate, recovered oil recovered from a coke oven, or waste oil. Polystyrene waste disposal method. In hazardous polystyrene foam waste treatment equipment that detoxifies hazardous polystyrene foam waste,
A gasification reforming melting furnace having a pyrolysis section, a gas reforming section and a melting section;
A block compression supply device for compressing and molding another waste to form a block, and supplying the block to a thermal decomposition section of a gasification reforming melting furnace;
A solution supply device for supplying a solution generated by dissolving hazardous polystyrene foam waste in a solvent to a thermal decomposition section of a gasification reforming melting furnace,
The pyrolysis section of the gasification reforming melting furnace pyrolyzes the block and the solution, the gas reforming section reforms the gasification gas, and the melting section melts the pyrolysis residue and incombustible material. Hazardous polystyrene foam waste treatment equipment.

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