JP7111123B2 - Waste recycling method and device - Google Patents

Description

The present invention relates to a waste recycling method and apparatus.

Shredder dust is a residue generated after scraping automobiles, home electric appliances, etc., after crushing them in a crusher and removing large-sized valuable metals. Shredder dust contains fine metal pieces, fibers, waste plastics (including a large amount of thermoplastic resin), rubber, wood, sand, and the like, and is difficult to physically separate and difficult to recycle. For this reason, recycling centered on thermal recycling, in which heat is recovered by burning shredder dust without physically separating it, has hitherto been carried out.

However, in order to promote material recycling and effectively utilize the components in the shredder dust, techniques for separating and recovering the components in the shredder dust have been studied. For example, in Patent Document 1, resin-based waste mixed with iron is introduced into a pyrolysis furnace and pyrolyzed, and the pyrolysis gas generated by the pyrolysis is recovered, and the pyrolysis residue generated by the pyrolysis is A method of introducing molten iron into a melting furnace and melting it to recover molten iron is disclosed. According to this method, the pyrolysis gas can be recovered, and the molten iron can be recovered from the pyrolysis residue.

JP-A-2003-71418

However, depending on the technique described in Patent Document 1, in addition to the pyrolysis furnace for pyrolyzing resins such as plastics, an iron recovery machine for separating iron-based residue and non-ferrous component-based residue is separately required. there were. Therefore, there has been a demand for a method of thermally decomposing the resin in the waste and separating the metal contained in the waste with a simpler device configuration.

That is, the present invention realizes recovery of pyrolysis gas by pyrolysis of resin and separation of the two or more metals from waste in which resin and two or more metals are mixed with a simple device configuration. intended to

The present inventors have made extensive studies to achieve the above object. As a result, the present inventors have developed a novel waste recycling method and an apparatus for use in the waste recycling method described below.

That is, the gist and configuration of the present invention are as follows.
(1) introducing waste containing a mixture of resin and two or more metals into a fluidized bed heating furnace, and heating the waste while fluidizing it;
While thermally decomposing the resin by heating and recovering the thermal decomposition gas generated by the thermal decomposition,
A waste recycling method, wherein the two or more metals are gravity-separated into two or more layers by flow.

(2) The waste recycling method according to (1) above, wherein at least one of the two or more metals is an iron-based metal.

(3) The waste recycling method according to (1) or (2) above, wherein the temperature in the fluidized bed heating furnace is 700°C or higher and 1000°C or lower.

(4) The waste recycling method according to any one of (1) to (3) above, wherein the waste is shredder dust.

(5) From (1) above, the metal contained in each layer after specific gravity separation is discharged from a plurality of discharge ports provided along the height direction of the fluidized bed heating furnace for each metal contained in each layer. (4) The method for recycling waste according to any one of items (4).

(6) introducing a fluidized medium in addition to the waste into a fluidized bed heating furnace, and heating the waste and the fluidized medium while fluidizing them;
The waste recycling method according to any one of (1) to (5) above, wherein the two or more metals are gravity-separated into two or more layers with the fluid medium as a boundary.

(7) The waste recycling method according to (6) above, wherein two or more types of the fluid medium are used, and the two or more metals are separated into three or more layers with the fluid medium as a boundary.

(8) A device used in the waste recycling method according to any one of (1) to (7) above,
a fluidized bed heating furnace, wherein the waste is heated while being fluidized to thermally decompose the resin by heating to generate a thermal decomposition gas, and the two or more metals are separated by specific gravity into two or more layers by fluidization;
a recovery device for recovering the pyrolysis gas discharged from the fluidized bed heating furnace;
a plurality of discharge ports provided along the height direction of the fluidized bed heating furnace for discharging the metal contained in each layer after specific gravity separation for each metal contained in each layer;
A device comprising:

According to the present invention, a thermal decomposition gas generated by pyrolysis of a resin and a separation of the two or more metals from a waste containing a mixture of resin and two or more metals can be recovered with a simple device configuration. can be realized.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic diagram showing an example of an apparatus and ancillary equipment used in a waste recycling method according to an embodiment of the present invention;

The present invention will be described based on the following embodiments. In the present application, “specific gravity” refers to the ratio of the mass of a sample to the mass of pure water of the same volume at 4° C. at a pressure of 1013.25 hPa. In particular, the "apparent specific gravity" is a specific gravity that includes the internal voids of the sample, and the sum of the volume occupied by the substance itself and the volume of the internal voids is the volume for specific gravity calculation. In addition, "resin" includes both plastic and rubber. Plastic is a plastic material whose main raw material is a polymer derived from petroleum. “~ Main metal” refers to a metal in which the ratio of the main element in the component composition is 60% by mass or more. For example, iron-based metals include steel, cast iron, scrap iron, and the like.

[Waste recycling method]
A waste recycling method according to an embodiment of the present invention comprises:
Introducing waste containing a mixture of resin and two or more metals into a fluidized bed heating furnace, heating the waste while fluidizing it,
While thermally decomposing the resin by heating and recovering the thermal decomposition gas generated by the thermal decomposition,
It is a method for recycling waste, in which the two or more metals are gravity-separated into two or more layers by flow.

In the waste recycling method according to the present embodiment, waste such as shredder dust containing a mixture of resin and two or more metals is introduced into a fluidized bed heating furnace, and the waste is heated while being fluidized. As a result, the resin is thermally decomposed by heating to generate thermal decomposition gas. In addition, two or more kinds of metals contained in the waste are fluidized by the gasifying agent introduced into the furnace to form a fluidized bed, and in the fluidized bed, metals having a higher apparent specific gravity settle and smaller metals levitate. As a result, two or more kinds of metals are gravity-separated into two or more layers, with a metal having a higher apparent specific gravity as a lower layer and a metal having a smaller apparent specific gravity as an upper layer. As described above, according to the present embodiment, two or more metals can be gravity-separated by fluidization while recovering pyrolysis gas in a single fluidized bed heating furnace. By providing a plurality of outlets for discharging the two or more metals from the fluidized bed heating furnace along the height direction of the fluidized bed heating furnace, the two or more metals separated by specific gravity can be discharged from the fluidized bed heating furnace. Each metal contained in each layer present at the exit level can be ejected. In particular, by installing the discharge port for discharging the iron-based metal, which is expected to have the highest apparent specific gravity, at the lowest point in the height direction of the fluidized bed heating furnace, the iron-based metal is recovered separately from other metals. can do.

According to the waste recycling method according to the present embodiment, thermal decomposition of resin and separation of two or more metals from waste such as shredder dust in which resin and two or more metals are mixed are performed. , can be realized in the fluidized bed furnace 20 . In addition, in the present embodiment, since the waste is heated while flowing, the efficiency of heat transfer to the waste is improved, and the resin can be efficiently heated and thermally decomposed. Furthermore, viscous solids, such as tar, which are mixed with the waste or produced by combustion of resin in the waste, may exist in the fluidized bed heating furnace. These viscous solids may stick to the fluidized bed heating furnace, but in this embodiment, the waste is heated while being fluidized to prevent these viscous solids from sticking to the fluidized bed heating furnace. can do. By heating the waste while flowing it, it is expected that the iron-based metal will catalyze the thermal decomposition of the resin.

A case where the waste recycling method according to the present embodiment is applied to the apparatus shown in FIG. 1 will be described below as an example. FIG. 1 is a schematic diagram showing an example of an apparatus and ancillary equipment used in the waste recycling method according to the present embodiment. As shown in FIG. 1, the apparatus used in the waste recycling method according to the present embodiment includes a fluidized bed heating furnace 20 and a recovery device 33 for recovering the pyrolysis gas discharged from the fluidized bed heating furnace 20. , and discharge ports 24a and 24b for discharging iron and other metals separated by specific gravity in the fluidized bed heating furnace by type. Recovery device 33 includes, in one example, cyclone dust collector 29 , cooler 30 , tar trap 34 , dehydrator 31 , and gas analyzer 32 . The apparatus used in the waste recycling method may further include a heater 35 for heating the fluidized bed heating furnace 20 .

First, a waste containing a mixture of resin and two or more kinds of metals is put into the inlet 25 provided in the upper part of the fluidized bed heating furnace 20 . If it is difficult to put the waste into the fluidized bed heating furnace 20 due to the shape, size, moisture content, etc. of the waste, waste plastic may be mixed with the waste and molded. Inside the fluidized bed heating furnace 20, it is not necessary to introduce a fluidizing medium 23, which will be described later, in addition to the waste.

Waste Containing Resin and Two or More Types of Metals In the present embodiment, resins and metals having different apparent specific gravities are mixed in the waste to be recycled. The waste can be a residue generated after crushing with a crusher and removing large-sized valuable metals when disposing of automobiles, home electric appliances, and the like. Waste can include resins and two or more metals, as well as fibers, waste plastics (mostly thermoplastic resins), rubbers, wood, sand, and the like. As described above, conventionally, it has been difficult to material-recycle waste in which resin and two or more metals are mixed. However, according to the present embodiment, thermal decomposition of resin and separation of two or more metals can be realized in the single fluidized bed heating furnace 20, and material recycling can be promoted.

In the fluidized bed heating furnace 20, the waste is heated while being fluidized. As a result, the resin in the waste is pyrolyzed and gasified to generate pyrolysis gas.

Gasification agent A gasification agent is introduced from the lower part of the fluidized bed heating furnace 20 . The gasifying agent gasifies the resin contained in the waste. Further, the waste is fluidized by the gasifying agent to form a fluidized bed, and two or more kinds of metals are fluidized and gravity-separated into two or more layers. The gasifying agent is preferably water vapor, carbon dioxide, exhaust gas discharged from a steelworks (steelworks exhaust gas), or a combination thereof. If a low-temperature gasifying agent is introduced into the fluidized bed heating furnace 20, the temperature inside the furnace may drop. Therefore, it is preferable to introduce the gasifying agent into the furnace while heating the gasifying agent. The method of heating the gasifying agent is not particularly limited, but for example, the dispersing/rectifying unit 21, such as alumina balls, in the lower part of the fluidized bed heating furnace 20 can disperse/rectify the gasifying agent and also has a preheating function. and heating the dispersion/rectification unit 21 . By introducing the gasifying agent through the gaps of the heated dispersing/rectifying unit 21, the gasifying agent is heated by the dispersing/rectifying unit 21, and the heated gasifying agent is introduced into the fluidized bed heating furnace 20. be able to. In addition, by introducing the gasification agent through the gaps of the dispersion/rectification unit 21, the gasification agent is introduced into the fluidized bed heating furnace 20 in a dispersed state, thereby further improving the fluidity of the waste. can also Although the equipment configuration for introducing the gasification agent from the lower part of the fluidized bed heating furnace 20 is not particularly limited, for example, as shown in FIG. 1, a mass flow controller 27 for adjusting the flow rate of N ₂ ), a pump 26 for introducing a liquid (H ₂ O in FIG. 1) that vaporizes to become a gasifying agent, and various gasifying agents. A gasification agent heater 28 may be provided for heating and for vaporizing a liquid that vaporizes into a gasification agent.

In order to introduce the gasifying agent into the fluidized bed heating furnace 20 in a dispersed state, the lower part of the fluidized bed heating furnace 20 is covered with a dispersing/rectifying section 21, or the bottom of the furnace is provided with ejection holes for the gasifying agent. It is preferable to disperse and provide them.

Temperature inside the fluidized bed heating furnace: 700° C. or more and 1000° C. or less By raising the inside temperature of the fluidized bed heating furnace 20 to a high temperature, the resin in the waste is heated and thermally decomposed. The temperature inside the fluidized bed heating furnace 20 is preferably 700° C. or higher. By setting the temperature in the fluidized bed heating furnace 20 to 700° C. or higher, it is possible to prevent the generation of tar in the furnace, and thus it is possible to prevent the piping of the fluidized bed heating furnace 20 from being clogged with tar. . Also, the temperature in the fluidized bed heating furnace 20 is preferably 1000° C. or less. By setting the temperature in the fluidized bed heating furnace 20 to 1000° C. or less, it is possible to prevent the iron-based metal in the waste from melting and to more preferably separate the iron-based metal by specific gravity. Furthermore, by setting the temperature in the fluidized bed heating furnace 20 to 700° C. or higher and 1000° C. or lower, the hydrogen concentration in the pyrolysis gas can be increased. From the viewpoint of suitably thermally decomposing the resin and increasing the amount of thermal decomposition gas recovered, the temperature in the fluidized bed heating furnace 20 is more preferably 800° C. or higher, more preferably 850° C. or higher. . The temperature in the furnace is measured by lowering a thermocouple into the furnace from the upper part of the fluidized bed heating furnace. The temperature measurement position is the central portion in the radial direction and the height direction of the portion where the heater 35 of the fluidized bed heating furnace 20 is provided.

In addition to measuring the temperature inside the fluidized bed heating furnace 20 at the central portion in the radial direction and the height direction of the portion where the heater 35 of the fluidized bed heating furnace 20 is provided, Temperature measurements are preferably made at the point. By measuring temperatures at a plurality of locations in the height direction of the fluidized bed heating furnace 20, it is possible to estimate the types of substances contained in the bed existing at the locations where the temperatures are measured.

Recovery of Pyrolysis Gas Pyrolysis gas generated by thermal decomposition of the resin is recovered by the recovery device 33 . Although the configuration of the recovery device 33 is not particularly limited, the recovery device 33 includes a cyclone dust collector 29, a cooler 30, a tar trap 34, a dehydrator 31, and a gas analyzer 32 in this embodiment. In this embodiment, the pyrolysis gas is led to the cyclone dust collector 29 through the flow path provided in the fluidized bed heating furnace 20 . In the cyclone dust collector 29, char and salts in the pyrolysis gas are recovered as dust. The pyrolysis gas from which dust has been removed is then introduced to cooler 30 and cooled. The pyrolysis gas after cooling is led to the tar trap 34 and the dehydrator 31 . By providing the recovery device 30 with the tar trap 34, it is possible to suitably prevent the generation of tar when the pyrolysis gas is used in another device. Moreover, the water vapor contained in the pyrolysis gas can be removed by providing the recovery device 30 with the dehydrator. The pyrolysis gas after dehydration is guided to the gas analyzer 32 and appropriately analyzed for components. The gas analyzer 32 may be a Gas Chromatograph-Thermal Conductivity Detector (GC/TCD) with a thermal conductivity detector.

The pyrolysis gas contains CO, _CH4 , etc. in addition to hydrogen. If the hydrogen concentration in the pyrolysis gas is insufficient, the hydrogen concentration in the pyrolysis gas can be further increased by performing subsequent steam reforming and dry reforming reactions on the recovered pyrolysis gas. can. Such steam reforming and dry reforming reactions include, for example, the reactions shown below.
CO+ _H2O → _{CO2 +} H2
CH4+CO→2CO _{+ 2H2}

Two or More Metals Pyrolysis residue containing two or more metals is generated by thermal decomposition of the resin in the waste. The two or more metals may include iron-based metals, tin-based metals, aluminum-based metals, copper-based metals, and the like. The two or more metals are fluidized in the fluidized bed heating furnace 20 and separated into layers in the fluidized bed heating furnace 20 by specific gravity. According to this embodiment, metals having apparent specific gravities different by ±10% or more can be separated from each other. Therefore, according to this embodiment, the tin-based metal, the aluminum-based metal, and the copper-based metal can be separated by specific gravity for each type. In this specification, the apparent specific gravity is measured according to JIS Z 2504.

Fluidized Medium A fluidized medium 23 may be introduced into the fluidized bed heating furnace 20 in addition to the waste. By introducing the fluid medium 23 in addition to the waste, two or more metals can be more preferably separated by specific gravity. Silica sand; FCC (Fluid Catalytic Cracking) catalyst containing zeolite or the like; and glass grains can be used as an example of the fluid medium 23 . For the purpose of catalyzing the pyrolysis reaction and increasing the recovery amount of iron-based metals, dust generated in the iron-making process (iron-making dust) may be used as the fluidizing medium 23 . Steelmaking dust includes blast furnace dust, sludge, converter dust, sintering dust, electric furnace dust, mill scale, and the like. From the viewpoint of cost, it is preferable that the fluid medium 23 is inexpensive. If an inexpensive material is used as the fluidizing medium 23, even if the fluidizing medium 23 is frequently extracted from the fluidized bed heating furnace 20, the increase in cost can be prevented. The particle size of the fluid medium is not particularly limited, but in one example, a fluid medium with a diameter of 10 mm or less can be used.

The apparent specific gravity of the fluid medium 23 may be determined for each of two or more metals to be subjected to specific gravity separation. The apparent specific gravity of the fluid medium 23 is preferably an intermediate apparent specific gravity between any two metals selected from two or more metals. If the apparent specific gravity of the fluidized medium 23 is intermediate between the apparent specific gravities of the two types of metals, the metal having an apparent specific gravity greater than that of the fluidized medium 23 settles in the fluidized medium 23, and conversely, the metal having an apparent specific gravity higher than that of the fluidized medium 23 settles. Small metals float in the fluid medium 23 . Therefore, two or more metals to be subjected to specific gravity separation can be moved to upper and lower parts of the fluid medium 23 with the fluid medium 23 as a boundary, and the two or more metals can be specifically gravity-separated.

The fluid medium 23 may be used in combination of multiple types. By using a combination of a plurality of fluid media 23, two or more metals can be more preferably separated by specific gravity. For example, by using two or more fluid media 23 having different apparent specific gravities as the fluid media 23, three or more metals can be more preferably separated by specific gravity. Two or more types of fluid media 23 having different apparent specific gravities are separated into two or more layers in the heating furnace 20 for each apparent specific gravity. The three or more metals flowing in the two or more layers of fluid medium 23 sink or float in each layer depending on the apparent specific gravity of the fluid medium 23 constituting each layer, and the upper portion of each layer 23 Alternatively, the lower layer is separated by specific gravity to form three or more layers. Thereby, three or more kinds of metals can be particularly suitably separated by specific gravity. More preferably, three or more types of fluid media 23 with different apparent specific gravities, and still more preferably four or more types of fluid media 23 with different apparent specific gravities are used. When using a plurality of types of fluid media 23 with different apparent specific gravities, it is preferable to use fluid media 23 with different apparent specific gravities of ±10% or more. For example, silica sand and steelmaking dust can be used as the fluidizing medium 23 when iron-based metals, copper-based metals, and aluminum-based metals are separated by specific gravity.

The amount of the fluidized medium 23 introduced into the fluidized bed heating furnace 20 is not particularly limited, but can be determined according to the position (height) of the discharge port 24 and the amount and type of metal to be recovered. After gravity separation, the height of the layer containing the metal to be recovered depends on the amount of the fluid medium 23 used (the height of the layer formed by the fluid medium 23). Therefore, by changing the amount of the fluid medium 23, the height of the layer containing the metal to be recovered can be matched with the height of the outlet 24 for discharging the separated metal.

The fluidized medium may be introduced into the fluidized bed heating furnace 20 in a heated state. By introducing the heated fluidized medium into the fluidized bed heating furnace 20, the waste can be heated more appropriately. When the fluidized medium is introduced into the fluidized bed heating furnace 20 in a heated state, the heater 35 for heating the fluidized bed heating furnace 20 may not be provided in the apparatus used in the waste recycling method. .

Discharge Port In order to take out two or more metals separated by specific gravity from the fluidized bed heating furnace 20, the fluidized bed heating furnace 20 is provided with discharge ports 24a and 24b passing through the furnace wall along the height direction. . By providing the discharge port 24 along the height direction of the fluidized bed heating furnace 20, two or more metals separated by specific gravity into two or more layers are discharged by type from the discharge port 24 provided at the height of each layer. can be recovered. For example, as shown in FIG. 1, light metal is discharged from the upper discharge port 24a. Further, the iron-based metal having a large apparent specific gravity is discharged from the lower discharge port 24b. By providing the discharge port 24 along the height direction of the fluidized bed heating furnace 20 in this way, two or more metals can be separated without separate magnetic separation or the like after thermal decomposition of the resin as in the conventional art. , has the effect of cost reduction.

The height of the discharge port 24 of the fluidized bed heating furnace 20 is preferably designed for each type of two or more metals contained in each layer after gravity separation. As described above, the height at which the metal is discharged after specific gravity separation can be adjusted to some extent by the amount of the fluidized medium 23 introduced into the fluidized bed heating furnace 20. Depending on the discharge port provided for the purpose, two or more metals separated by specific gravity cannot be discharged at the same time. On the other hand, by using the fluidized bed heating furnace 20 in which the height of the discharge port 24 of the fluidized bed heating furnace 20 is designed for each type of metal to be recovered after specific gravity separation, the metal contained in each layer can be Each metal contained in each layer can be suitably discharged from the heating furnace 20 and recovered.

Each discharge port 24 can be opened and closed by an opening/closing member such as a valve, and the discharge port 24 can be opened when discharging the metal. The position, number and size of the discharge ports 24 can be determined according to the type of metal to be discharged. A layer containing a substance having the highest apparent specific gravity is discharged from the lowermost discharge port 24 of the fluidized bed heating furnace 20 . When shredder dust is used as the waste, iron, which is considered to have the highest apparent specific gravity, is discharged from the lowermost outlet 24 of the fluidized bed heating furnace 20 . The discharged iron can be put into a melting furnace or the like without pretreatment as a substitute for reduced iron (iron scrap) and melted without pretreatment, and molten iron can be recovered. When shredder dust is used as the waste, light metals such as tin-based metals, aluminum-based metals, and copper-based metals are discharged from the upper part of the fluidized bed heating furnace 20 in the height direction. can be In addition, in order to facilitate removal of the separated metal, the discharge port 24 may be appropriately provided with a suction portion for sucking the metal out of the fluidized bed heating furnace 20 . A mesh filter may be provided at the discharge port 24 . By providing a mesh filter at the discharge port 24, the substances contained in the layer after gravity separation can be sieved according to the size.

The timing of discharging the metal contained in each layer after gravity separation from the discharge port 24 of the fluidized bed heating furnace 20 can be appropriately determined according to the type of metal to be gravity separated, flow conditions, and the like. The metal contained in each layer can be discharged while operating the fluidized bed heating furnace 20, or after operating the fluidized bed heating furnace 20 for a certain period of time and ending the operation. From the viewpoint of operational efficiency, it is preferable to discharge the metal contained in each layer while operating the fluidized bed heating furnace 20 . Further, by discharging the metal while operating the fluidized bed heating furnace 20, the metal contained in each layer can be discharged more easily.

The flow rate of the gasifying agent introduced from the bottom of the fluidized bed heating furnace 20 can be determined according to the type of metal to be gravity separated. The flow rate of the gasifying agent introduced from the lower part of the fluidized bed heating furnace 20 is preferably determined according to the metal having the lowest apparent specific gravity among the metals to be separated by specific gravity. By determining the flow conditions according to the metal with the smallest apparent specific gravity, it is possible to prevent the metal with the smallest apparent specific gravity from jumping up due to the flow and being recovered by the recovery device 30 together with the pyrolysis gas. can be performed.

A fluidizing medium 23 may be mixed with the metal discharged from the fluidized bed heating furnace 20 after gravity separation. The fluid medium 23 mixed with the ejected metal can be removed by known methods. The fluid medium 23 mixed with the discharged metal can be removed by sieving, magnetic separation, electrostatic precipitator, and the like.

[Device]
As described above, the apparatus used in the waste recycling method according to one embodiment of the present invention includes:
A device used in a waste recycling method,
a fluidized bed heating furnace, wherein the waste is heated while being fluidized to thermally decompose the resin by heating to generate a thermal decomposition gas, and the two or more metals are separated by specific gravity into two or more layers by fluidization;
a recovery device for recovering the pyrolysis gas discharged from the fluidized bed heating furnace;
a plurality of discharge ports provided along the height direction of the fluidized bed heating furnace for discharging the metal contained in each layer after specific gravity separation for each metal contained in each layer;
An apparatus comprising: An example of a specific device configuration is as described above with reference to FIG.

(Invention Example 1)
Using the fluidized bed heating furnace schematically shown in Fig. 1, a mixture of metallic iron (M-Fe) iron powder, aluminum powder (280 g/h), and polypropylene (280 g/h) simulating shredder dust was heated. It was made to flow while heating for 2 hours. The iron powder had an apparent specific gravity of 3100 kg/m ³ and the aluminum powder had an apparent specific gravity of 1000 kg/m ³ . The temperature inside the furnace was 1000°C, and 1827 g of converter dust was used as the fluidizing medium. The apparent specific gravity of the converter dust was 2690 kg/m ³ . From the lower part of the fluidized bed, 1.4 NL/min of steam and 2.6 NL/min of nitrogen were fed as gasifying agents. After the heating for 2 hours was completed, the substances in the furnace were discharged by type from four outlets provided along the height direction of the fluidized bed heating furnace and collected to obtain collected substances. For each recovered substance, the substance content was determined by chemical analysis (ICP emission spectrometry). The amount of emissions per hour (g/h) was obtained from the total amount of emissions of each substance. The amount of the mixture was defined as a value obtained by subtracting the sum of the recovered amounts of the respective substances from the total amount of the substances charged into the furnace. In addition, when the content of the substance in the recovered substance was 90 wt % or more, it was judged that the gravity separation was completed. Also, hydrogen gas was recovered from the furnace top, and the flow rate was measured with a gas analyzer.

(Invention Example 2)
An experiment was conducted in the same manner as in Invention Example 1, except that a mixture of 914 g of converter dust and 474 g of silica sand was used as the fluidizing medium. The apparent specific gravity of silica sand was 1240 kg/m ³ .

(Invention example 3)
Except for using a mixture of M-Fe iron powder (93 g/h), aluminum powder (93 g/h), copper powder (93 g/h), and polypropylene (280 g/h) as a mixture simulating shredder dust. conducted an experiment in the same manner as in Invention Example 1. Incidentally, the apparent specific gravity of the copper powder was 3600 kg/m ³ .

(Invention Example 4)
An experiment was conducted in the same manner as in Invention Example 1, except that no fluid medium was used.

(Comparative example 1)
An experiment was conducted in the same manner as in Invention Example 1, except that a rotary kiln was used instead of the fluidized bed heating furnace.

As shown in Table 1, in Invention Example 1 and Comparative Example 1, it was found that approximately the same hydrogen gas yield was obtained. In Comparative Example 1, the M-Fe powder, aluminum powder, copper powder, and converter dust in the fluidized medium could not be separated from the simulated shredder dust, so they were all discharged as a mixture. On the other hand, in Invention Example 1, M-Fe iron powder, aluminum powder, copper powder, and converter dust could be separated and recovered. Further, when comparing the hydrogen gas yields of Invention Examples 1 to 4, Invention Example 1>Invention Example 3>Invention Example 2>Invention Example 4. This is considered to be due to the catalytic effect of iron powder, converter dust, and aluminum powder.

20 Fluidized bed heating furnace 21 Dispersion/rectification unit 23 Fluid medium 24a, b Discharge port 25 Input port 26 Pump 27 Mass flow controller 28 Gasification agent heater 29 Cyclone dust collector 30 Cooler 31 Dehydrator 32 Gas analyzer 33 Recovery Device 34 Detar device 35 Heater

Claims (8)

Introducing waste containing a mixture of resin and two or more metals into a fluidized bed heating furnace, heating the waste while fluidizing it,
While thermally decomposing the resin by heating and recovering the thermal decomposition gas generated by the thermal decomposition,
A waste recycling method, wherein the two or more metals are gravity-separated into two or more layers by flow. 2. The waste recycling method according to claim 1, wherein at least one of the two or more metals is an iron-based metal. 3. The waste recycling method according to claim 1, wherein the temperature in said fluidized bed heating furnace is 700[deg.] C. or more and 1000[deg.] C. or less. The waste recycling method according to any one of claims 1 to 3, wherein the waste is shredder dust. 5. The method according to any one of claims 1 to 4, wherein the metal contained in each layer after specific gravity separation is discharged from a plurality of discharge ports provided along the height direction of the fluidized bed heating furnace for each metal contained in each layer. The method for recycling waste according to item 1. In addition to the waste, a fluidized medium is further introduced into the fluidized bed heating furnace, and the waste and the fluidized medium are heated while being fluidized,
6. The waste recycling method according to any one of claims 1 to 5, wherein the two or more metals are gravity-separated into two or more layers with the fluid medium as a boundary. 7. The waste recycling method according to claim 6, wherein two or more kinds of said fluid media are used, and said two or more kinds of metals are separated into three or more layers with said fluid media as boundaries. A device used in the waste recycling method according to any one of claims 1 to 7,
a fluidized bed heating furnace, wherein the waste is heated while being fluidized to thermally decompose the resin by heating to generate a thermal decomposition gas, and the two or more metals are separated by specific gravity into two or more layers by fluidization;
a recovery device for recovering the pyrolysis gas discharged from the fluidized bed heating furnace;
a plurality of discharge ports provided along the height direction of the fluidized bed heating furnace for discharging the metal contained in each layer after specific gravity separation for each metal contained in each layer;
A device comprising:

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