Thermal decomposition device

Abstract

To provide a thermal decomposition device capable of sending a condensate liquid to an appropriate process according to concentration of impurities while being stably operated.SOLUTION: A thermal decomposition device 1 includes: a thermal decomposition section 20 for heat-decomposing a raw material resin; a condensation section 30 for liquefying thermal decomposition gas; and a storage section 40 for storing a condensate liquid. The storage section 40 has two or more tanks 41, 42 connected in parallel or series. At least one kind of a processing section related to a next process is connected to the discharge sides of the tanks 41, 42. A removal port S for condensate liquid is provided in at least one of the storage section 40 and a secondary piping P2 between the storage section 40 and the processing section.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a resin pyrolysis device. [Background technology]

[0002] In recent years, with the rise in resource prices and growing awareness of environmental issues, there has been a growing trend to collect and recycle resin molded products such as poly(meth)acrylic esters. One known example is a method in which poly(meth)acrylic esters are thermally decomposed (depolymerized) to recover the resulting monomer, which is then used to produce a new molded product. This type of resin recycling method is also called chemical recycling.

[0003] In the regeneration process of poly(meth)acrylic esters, the monomers, which are pyrolysis products, are recovered in high yields by heating at a relatively low temperature of around 300 to 500°C. In this respect, poly(meth)acrylic esters are suitable for regeneration by chemical recycling.

[0004] For example, Patent Document 1 describes a method in which a resin product containing a poly(meth)acrylic acid ester is heated in a heating furnace to obtain a gaseous pyrolysate, which is then cooled and liquefied, and the liquefied pyrolysate is then purified by distillation to recover the (meth)acrylic acid ester. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-321571 Summary of the Invention [Problem to be solved by the invention]

[0006] After the thermal decomposition of resin, the liquefied pyrolysis product (condensate or recovered liquid) may contain impurities. While a low impurity concentration is desirable in the regeneration process, the impurity concentration may be high depending on the raw materials fed in. Therefore, it is desirable to operate the pyrolysis device stably and send the condensate to the appropriate process depending on the impurity concentration.

[0007] An object of the present disclosure is to provide a thermal decomposition apparatus that can operate stably and send condensate to an appropriate process depending on the concentration of impurities. [Means for solving the problem]

[0008] The present disclosure provides several aspects as follows. [1] A thermal decomposition unit that receives and thermally decomposes raw resin; a condensation section for liquefying the pyrolysis gas discharged from the pyrolysis section; a storage section that stores the condensed liquid condensed in the condensation section, the storage unit has two or more tanks connected in parallel or in series, and at least one type of processing unit related to a next process is connected to the discharge side of the tanks; A pyrolysis apparatus, wherein an outlet for the condensate is provided in at least one of the storage section and a secondary pipe between the storage section and the processing section.

[0009] According to the pyrolysis device of [1], the storage section has two or more tanks, and these tanks can be used appropriately. For example, condensate can be stored in one tank, and then analyzed for impurities. While waiting for the analysis results, the condensate can be stored in another tank. During the analysis, the condensate can be removed from the outlet, allowing for accurate measurement of the impurity concentration. By using the tanks appropriately, the downtime for stopping the pyrolysis section is either eliminated (in which case continuous operation is possible) or is kept short. Therefore, the pyrolysis device can be operated stably, and the condensate can be sent to the appropriate process depending on the impurity concentration shown in the analysis results.

[0010] [2] The thermal decomposition apparatus according to [1], wherein the processing section has at least one of a purification section for purifying the condensate and a filling section for filling the condensate for shipping. In this case, depending on the concentration of impurities, the condensate can be purified or sent to an appropriate process, such as filling the condensate for shipping.

[0011] [3] The thermal decomposition apparatus according to [2], wherein the processing section has both a purification section for purifying the condensate and a filling section for filling the condensate for shipping, and the secondary piping is provided with a next-process switching means for switching the discharge destination of the condensate from the storage section to the purification section or the filling section. In this case, purification or filling (shipping) can be appropriately selected depending on the concentration of impurities.

[0012] [4] The thermal decomposition apparatus according to any one of [1] to [3], wherein a dehydration section, an adsorption section, or an absorption section is provided between the storage section and the treatment section. In this case, impurities can be removed while the condensate is being discharged from the storage section (while the upstream thermal decomposition section is operating, depending on the situation).

[0013] [5] The thermal decomposition device according to any one of [1] to [4], wherein a residue storage section is connected to the thermal decomposition section. In this case, the residue generated in the thermal decomposition section is discharged to the residue storage section without remaining in the thermal decomposition section, which makes it easy to prevent impurities derived from the residue from being mixed into the gas.

[0014] [6] The thermal decomposition apparatus according to any one of [1] to [5], wherein a partial condenser is provided between the thermal decomposition section and the condensation section, in which case substances (also called high-boiling-point impurities) contained in the thermal decomposition gas and having a boiling point higher than that of the substance to be recovered can be removed.

[0015] [7] The pyrolysis apparatus according to any one of [1] to [6], wherein the storage unit has two or more tanks connected in parallel, and the storage unit is provided with a tank switching means for introducing the condensate into one of the tanks. In this case, the two tanks can be alternately used for storage and analysis.

[0016] [8] The pyrolysis apparatus according to any one of [1] to [6], wherein the storage unit has two or more tanks connected in series, and the storage unit is provided with a liquid delivery means for delivering the condensate to a downstream tank. In this case, the downstream tank is used exclusively for analysis, and the upstream tank is used exclusively for receiving and storing the condensate. [Effects of the Invention]

[0017] According to the present disclosure, the pyrolysis device can be operated stably, and the condensate can be sent to an appropriate process depending on the concentration of impurities shown in the analysis results. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a flow diagram of a pyrolysis apparatus according to one embodiment of the present disclosure. [Figure 2] FIG. 2(a) shows the parallel version of the reservoir, and FIG. 2(b) shows the serial version of the reservoir. [Figure 3] Figures 3(a), 3(b) and 3(c) are diagrams illustrating an example of operation of the parallel version of the storage section. [Figure 4] FIG. 4 is a diagram corresponding to FIGS. 3(a) to 3(c), and shows examples of the use of each tank in chronological order. [Figure 5] 5(a), 5(b) and 5(c) are diagrams illustrating an example of operation of the series version of the storage section. [Figure 6] FIG. 6 is a flow diagram of a pyrolysis apparatus according to another embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0019] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements are designated by the same reference numerals, and duplicated description will be omitted.

[0020] A resin pyrolysis apparatus 1 according to one embodiment of the present disclosure is an apparatus for obtaining monomers by thermally decomposing (depolymerizing) used resin molded bodies (e.g., recovered products from the market) or discarded resin molded bodies (e.g., factory waste). The pyrolysis apparatus 1 can also process post-consumer recycled plastic (PCR), not just plastics from factories. The monomers obtained by the pyrolysis apparatus 1 are repolymerized in a separate device to obtain polymers (or recycled monomers). The monomers obtained by pyrolysis, i.e., pyrolyzed monomers, may contain several types of impurities. The pyrolysis apparatus 1 can appropriately process the pyrolyzed monomers by measuring the impurity concentration while continuing the pyrolysis process of the resin. The pyrolysis apparatus 1 enables in-process management of chemically recycled monomers. The pyrolysis apparatus 1 of this embodiment, combined with a separate repolymerization apparatus, enables chemical recycling of any resin. In this specification, "used or discarded resin" may also be referred to as "raw material" or "raw material resin."

[0021] The type of resin to be recovered by the thermal decomposition apparatus 1 is not particularly limited. The thermal decomposition apparatus 1 may thermally decompose (meth)acrylic resins, styrene-based resins, polycarbonate, or polyethylene terephthalate. For example, when polymethyl methacrylate (PMMA), which is one type of resin, is thermally decomposed, the monomer methyl methacrylate (MMA) is obtained. At this time, several low-boiling-point impurities are contained. For example, impurities may include methyl propionate, methyl isobutyrate, methyl acrylate, ethyl acrylate, butyl acrylate, methanol, etc. Note that with regard to methyl acrylate, it is believed that the influence of the raw material origin is significant.

[0022] Even when recycling a single type of resin, there are various types of impurities. The impurities may include typical impurities such as those described above, or may include special impurities. The impurities may be low-boiling point impurities or high-boiling point impurities. Low-boiling point impurities are substances with a lower boiling point than the resin to be recovered (i.e., the resin to be recycled). High-boiling point impurities are substances with a higher boiling point than the resin to be recovered (i.e., the resin to be recycled). The thermal decomposition device 1 can handle any type of impurity.

[0023] The types and amounts of impurities that can be tolerated in pyrolysis monomers may vary (or may be set appropriately) depending on the type of resin, or may vary (or may be set appropriately) for the same resin depending on the intended use after recycling. When the manner of use of recycled resins differs, the required level of impurity concentration in recycled resins often differs. The pyrolysis device 1 of this embodiment is applicable to all impurities and all concentration levels (the above-mentioned required levels).

[0024] The configuration of the thermal decomposition apparatus 1 will be described with reference to Fig. 1. As shown in Fig. 1, the thermal decomposition apparatus 1 includes a pretreatment section 10, a thermal decomposition section 20, a condensation section 30, a storage section 40, a purification section 50, a filling section 60, and a shipping section 70. Although Fig. 1 does not show valves, instruments, detailed piping configurations, etc., each section of the thermal decomposition apparatus 1 may employ a known detailed configuration for realizing the function of each section, which will be described later.

[0025] The pre-treatment section 10 pre-treats the raw resin before it is supplied to the pyrolysis section 20. Examples of pre-treatment include conventionally known processes such as a fine powder removal process, a metal removal process, and a process for separating or sorting different resins. The pre-treatment section 10 includes a pre-treatment device 11 that performs pre-treatment such as fine powder removal, and a first feeder 12 that supplies the pre-treated raw material to the pre-treatment section 10. The type of the first feeder 12 is not particularly limited and can be selected from known devices.

[0026] The pyrolysis section 20 performs pyrolysis of the raw material supplied from the pretreatment section 10. In other words, the pyrolysis section 20 receives and pyrolyzes raw material resin. The pyrolysis section 20 includes, for example, a resin receiving section 21, a second feeder 22, and a pyrolysis gasification device 23. The resin receiving section 21 can also be considered a resin inlet into which resin is introduced. The resin receiving section 21 is a raw material supply section that supplies raw material to the pyrolysis gasification device 23. The type of the second feeder 22 is not particularly limited and can be selected from known devices. Any of the pretreatment section 10, the resin receiving section 21, and the second feeder 22 may be provided with a device for processing the raw material, such as crushing, a detector for detecting foreign matter contained in the raw material, or a meter for controlling the amount of raw material introduced.

[0027] The pyrolysis gasification apparatus 23 thermally decomposes the raw material resin to obtain a gaseous pyrolysis product (hereinafter also referred to as pyrolysis gas). As the pyrolysis gasification apparatus 23, for example, an extrusion type apparatus or a fluidized bed type apparatus may be used. A kneader may also be used as the pyrolysis gasification apparatus 23. As the pyrolysis gasification apparatus 23, any known (arbitrary and suitable) apparatus capable of thermally decomposing the target raw material resin may be used.

[0028] Suitable examples of the pyrolysis gasification device 23 include twin-screw extruders such as a twin-screw co-rotating extruder and a twin-screw counter-rotating extruder. These extruders are equipped with a raw material inlet, a cylinder, and a screw disposed inside the cylinder, and are devices that can transport the raw material fed from the inlet in a predetermined direction while heating it.

[0029] An example of the pyrolysis gasification apparatus 23 being a kneader is the apparatus described in U.S. Patent No. 10,301,235. An example of the pyrolysis gasification apparatus 23 being a fluidized bed heater is the apparatus described in Japanese Patent Laid-Open No. 2009-112902.

[0030] The temperature at which the poly(meth)acrylic acid ester is thermally decomposed in the thermal decomposition section 20 may be selected from the range of, for example, 300°C to 500°C, 400°C to 500°C, or 450°C to 500°C.

[0031] The pyrolysis unit 20 (specifically, the pyrolysis gasification unit 23) is connected to, for example, a residue storage unit 26. The residue storage unit 26 stores the residue discharged from the pyrolysis gasification unit 23. The method for storing the residue is not particularly limited and can be selected from known methods. The residue storage unit 26 may be equipped with a processing device or the like that processes the residue into a disposable state.

[0032] Furthermore, a partial condenser may be provided between the thermal decomposition section 20 and the condensation section 30. The partial condenser, for example, condenses (liquefies) and removes high-boiling-point impurities contained in the gaseous thermal decomposition product obtained in the thermal decomposition section 20. By disposing the partial condenser downstream of the thermal decomposition section 20, the load of the purification process in the purification section can be further reduced. The removal of high-boiling-point impurities by the partial condenser is carried out, for example, at a temperature that is equal to or higher than the boiling point and lower than the ignition point of the substance contained in the thermal decomposition product to be recovered, and that is lower than the boiling point and higher than the melting point of the high-boiling-point impurities. In other words, the high-boiling-point impurities are removed while the thermal decomposition product as a whole remains in a gaseous state.

[0033] The condensation section 30 liquefies the pyrolysis gas discharged from the pyrolysis section 20. The condensation section 30 includes a cooling section. The condensation section 30 cools and liquefies the pyrolysis gas obtained in the pyrolysis section 20 to obtain a condensed liquid.

[0034] The temperature to which the pyrolysis gas is cooled is preferably lower than the boiling point of the substance to be recovered. For example, when the pyrolysis gas contains methyl methacrylate or methyl acrylate to be recovered, the pyrolysis gas is cooled to a temperature lower than 101°C, the boiling point of methyl methacrylate, or lower than 80°C, the boiling point of methyl acrylate. The configuration of the condenser 30 is not particularly limited, and a known device such as a condenser can be used.

[0035] The storage section 40 stores the condensate condensed in the condensation section 30. The storage section 40 stores the liquid pyrolysate (condensate) supplied from the condensation section 30 and supplies it to the downstream purification section 50 (or directly to the packing section 60). A dehydration section may be installed at any location within the storage section 40. The storage section 40 may have a known configuration that is applied to a storage means for a liquid pyrolysate (condensate).

[0036] As shown in FIGS. 1 and 2(a), the storage unit 40 has, for example, two tanks 41, 42 connected in parallel. The storage unit 40 includes a first tank 41 and a second tank 42, an inlet-side pipe 43 provided between these tanks 41, 42 and the condensation unit 30, and an outlet-side pipe 44 provided between these tanks 41, 42 and the purification unit 50 (a processing unit related to the next step). Each of the first tank 41 and the second tank 42 may be configured to be able to store condensate. Each of the first tank 41 and the second tank 42 may be cylindrical, prismatic, or spherical. The first tank 41 and the second tank 42 have approximately the same storage capacity.

[0037] The primary pipe P1 connected to the discharge port of the condensation section 30 is outside the range of the storage section 40. The secondary pipe P2 connected to the inlet port of the purification section 50 is also outside the range of the storage section 40. The range of the storage section 40 extends from the point where the primary pipe P1 branches off into the inlet pipe 43 to the point where the outlet pipe 44 joins with the secondary pipe P2.

[0038] As shown in FIG. 3(a), a first inlet valve V1a is provided at the connection portion of the inlet pipe 43 to the first tank 41, and a second inlet valve V2a is provided at the connection portion of the inlet pipe 43 to the second tank 42. A first outlet valve V1b is provided at the connection portion of the outlet pipe 44 to the first tank 41, and a second outlet valve V2b is provided at the connection portion of the outlet pipe 44 to the second tank 42. Each valve may be a manual valve or an automatic valve equipped with an appropriate actuator and controlled by a controller (not shown). These valves are tank switching means for introducing condensate into one of the tanks.

[0039] In the pyrolysis apparatus 1 of this embodiment, a condensate outlet is provided in at least one location of the storage section 40 or the secondary piping P2 extending from the storage section 40 to the purification section 50. For example, as shown in FIG. 2(a), a first outlet S1 is provided in a portion of the outlet piping 44 located between the first tank 41 and the secondary piping P2, and a second outlet S2 is provided in another portion of the outlet piping 44 located between the second tank 42 and the secondary piping P2. In this case, the first outlet S1 and the second outlet S2 are provided within the storage section 40. The first outlet S1 and the second outlet S2 each include, for example, a manual collection valve.

[0040] The condensate outlet allows sampling for analysis of the condensate in the storage unit 40. It is desirable that the storage unit 40 be provided with an agitator or a condensate circulation structure so that the condensate extracted through the outlet has the same properties as the condensate in the storage unit 40. For example, a configuration may be adopted in which the upstream end of a circulation pipe is connected to one location on each tank, the downstream end of the circulation pipe is connected to another location on each tank, and a circulation pump is provided on the circulation pipe, thereby circulating, stirring, and mixing the condensate in the tanks.

[0041] The condensate outlets are not limited to positions such as the first outlet S1 and the second outlet S2, and may be provided directly on the first tank 41 and the second tank 42. In this case, the condensate outlets may be provided in the lower parts of the first tank 41 and the second tank 42 (particularly, on the lower side or bottom, etc.). The condensate outlets may be provided in the secondary pipe P2. Three or more outlets may be provided. In this case, all of the outlets may be provided in the outlet pipe 44 or the secondary pipe P2, or all of the outlets may be provided directly on the tank. Alternatively, one or more of the outlets may be provided in the outlet pipe 44 or the secondary pipe P2, and one or more of the other outlets may be provided directly on the tank.

[0042] At the first outlet S1 and the second outlet S2, the operator opens the sampling valve at an appropriate time (for example, when a predetermined amount of condensate has accumulated in each tank and the inlet and outlet valves have been closed) to sample the condensate inside. Note that the respective sampling ports are not shown in Figure 3 and subsequent figures.

[0043] Returning to FIG. 1, the purification section 50 has multiple purification columns (first purification column 51 and second purification column 52) and a cooling mechanism 53. FIG. 1 is a diagram showing an embodiment in which low-boiling-point impurities are removed in the first purification column 51 and high-boiling-point impurities are removed in the second purification column 52. The purification section 50 purifies the condensate. Each of the first purification column 51 and the second purification column 52 purifies the liquid pyrolysate (condensate) obtained in the condensation section 30. In this specification, "purification of the pyrolysate" means increasing the proportion of the components to be recovered among the components contained in the pyrolysate.

[0044] In the first purification column 51, low-boiling-point impurities are removed from the liquid pyrolysate (condensate) obtained in the condensation section 30. Specifically, by purifying the pyrolysate in the first purification column 51, a gas mainly containing low-boiling-point impurities is discharged from the top of the first purification column 51, and a liquid containing a large amount of the components to be recovered is sent from the bottom of the first purification column 51 to the second purification column 52. The gas mainly containing low-boiling-point impurities discharged from the top of the first purification column 51 is cooled and liquefied by the cooling mechanism 53. From the viewpoint of purification efficiency, it is preferable to discard a portion of the cooled liquid (downward arrow in FIG. 1 ) and return the remainder to the first purification column 51.

[0045] In the second purifier 52, high-boiling-point impurities are removed from the liquid delivered from the bottom of the first purifier 51. Specifically, the liquid delivered from the bottom of the first purifier 51 is purified in the second purifier 52, so that a gas containing mainly the components to be recovered is discharged from the top of the second purifier 52, and a liquid containing high-boiling-point impurities accumulates at the bottom of the second purifier 52. The liquid that accumulates at the bottom of the second purifier 52 can be discarded by a known method. For example, the liquid that accumulates at the bottom of the second purifier 52 may be stored in a waste liquid tank 57 and then discarded. The gas that contains a large amount of the components to be recovered and that is delivered from the top of the second purifier 52 is cooled and liquefied by a cooling mechanism 53 and is sent to the packing section 60 as a product.

[0046] 1 shows a configuration in which low-boiling-point impurities are removed in the first purification column 51 and high-boiling-point impurities are removed in the second purification column 52, but the configuration of the purification section 50 is not limited to this example. It is also possible to adopt a configuration in which high-boiling-point impurities are removed in the first purification column 51 and low-boiling-point impurities are removed in the second purification column 52. In that case, an appropriate device configuration should be adopted so that a liquid containing a large amount of the component to be recovered is stored in the packing section 60.

[0047] The liquid pyrolysate introduced into the purification section 50 (first purification column 51 and second purification column 52) may or may not contain water. When the liquid pyrolysate introduced into the purification section 50 contains water, the water may or may not be removed in the purification section 50. The configuration of the purification section 50 is not particularly limited, and a known purification device such as a purification column can be applied.

[0048] The cooling mechanism 53 cools and liquefies the gas discharged from the first purifying column 51 and the second purifying column 52. The temperature to which the gas is cooled may be set appropriately depending on the gas discharged from the first purifying column 51 and the second purifying column 52, but is preferably a temperature lower than the boiling point of the main components contained therein. The configuration of the cooling mechanism 53 is not particularly limited, and known devices such as a condenser (for example, a double-tube type, a shell-and-tube type, a plate type, a spiral type, etc.) can be applied. As described above, the purified monomer storage tank 57 is a tank for storing and disposing of monomers containing a large amount of high-boiling-point impurities.

[0049] The filling section 60 fills the condensate for shipment. The filling section 60 has a plurality of filling drums (a first filling drum 61 and a second filling drum 62) or at least one purified monomer storage tank (not shown). The filling section 60 may include a filling container such as a drum can, or may include a larger storage (or retention) tank. When a large storage tank is provided, the condensate is filled from the storage tank into another smaller container. A dehydration section may be disposed inside the storage tank. The configuration of the filling section 60 is not particularly limited, and known devices can be applied. The purified monomer storage tank is a tank with a smaller capacity than the filling drums. The configuration of this storage tank is not particularly limited, and known tanks used for storage can be applied.

[0050] The shipping section 70 has a shipping tank 71 and / or shipping equipment 72. The shipping tank 71 may be refilled with the product, or the shipping equipment 72 may be used to fill the product into a tanker, lorry, container, drum, or the like, and ship it as is.

[0051] In the pyrolysis apparatus 1, both the purification section 50 and the filling section 60 are provided as processing sections related to the next step after the storage section 40. The secondary pipe P2 is provided with a subsequent processing switching means (not shown) that switches the discharge destination of the condensate from the storage section 40 to the purification section 50 or the filling section 60. The subsequent processing switching means may include a manual or automatic valve installed in the secondary pipe P2. The subsequent processing switching means may switch the liquid transfer route, and the condensate may bypass the purification section 50 (without passing through the purification step) and be filled in the filling section 60. Note that the condensate may be filled into a tank or the like (not shown) after passing through the purification section 50.

[0052] Furthermore, the pyrolysis apparatus 1 may be provided with a waste liquid storage section as a processing section for the next step after the storage section 40. The waste liquid storage section stores liquid pyrolysis products. The waste liquid storage section is connected to, for example, the secondary pipe P2. The configuration of the waste liquid storage section is not particularly limited, and a known device such as a tank can be applied.

[0053] The secondary piping P2 may be provided with a next-treatment switching means (not shown) that switches the discharge destination of the condensed liquid from the storage unit 40 between the purification unit 50 and a waste liquid storage unit, and may be provided with a next-treatment switching means (not shown) that switches the discharge destination of the condensed liquid from the storage unit 40 between the filling unit 60 and a waste liquid storage unit. The secondary piping P2 may be provided with a next-treatment switching means (not shown) that switches the discharge destination of the condensed liquid from the storage unit 40 between the purification unit 50, the filling unit 60, and a waste liquid storage unit.

[0054] Furthermore, any one of a dehydration section, an adsorption section, and an absorption section may be provided between the storage section 40 and the above-mentioned purification section 50, the filling section 60, or the waste liquid storage section.

[0055] The dehydration section removes water contained in the liquid condensate. The dehydration method is not particularly limited, and examples thereof include liquid-liquid separation, freeze concentration separation, distillation separation, membrane separation, adsorption separation, absorption separation, ultrasonic atomization separation, chromatography, etc. From the viewpoint of dehydration efficiency, the dehydration method is preferably carried out by a method in which a substance having a dehydrating function is brought into contact with the liquid condensate. An example of the dehydration function is the function of adsorbing or absorbing water. The treatment in the dehydration section may be carried out in a state in which the condensate is flowing or stationary. From the viewpoint of dehydration efficiency, the treatment in the dehydration section is preferably carried out in a state in which the condensate is flowing.

[0056] The adsorption unit includes, for example, a pipe through which the pyrolysis gas flows and an adsorbent disposed inside the pipe for adsorbing impurities. With this configuration, impurities can be removed while the pyrolysis gas is continuously transferred from the pyrolysis unit 20 to the condensation unit 30 and the storage unit 40.

[0057] The type of adsorbent is not particularly limited and can be selected depending on the type, concentration, etc. of the impurities to be removed. Specific examples of adsorbents include alumina, calcium oxide, calcium carbonate, iron oxide, iron hydroxide, carbon, zeolite, a composite of iron oxide and / or metallic iron with carbon, a composite of calcium oxide and carbon, a composite of iron oxide and / or metallic iron with calcium carbonate and / or calcium oxide and carbon, etc. The adsorbent in the adsorption section may be one type or two or more types.

[0058] From the viewpoint of increasing the efficiency of removing impurities from the pyrolysis gas passing through the removal section, it is preferable that the adsorbent has a large contact area with the pyrolysis gas, and from this viewpoint, the adsorbent is preferably in a particulate form.

[0059] The absorption unit includes, for example, a pipe through which the pyrolysis gas flows and an absorbent disposed inside the pipe for absorbing impurities. With this configuration, impurities can be removed while the pyrolysis gas is continuously transferred from the pyrolysis unit 20 to the condensation unit 30 and the storage unit 40.

[0060] A specific example of the absorbent is an aqueous solution containing a reducing agent and a base. By contacting this aqueous solution with the pyrolysis gas, impurities in the pyrolysis gas can be absorbed. The base is preferably selected from the group consisting of sodium hydroxide, sodium carbonate, and sodium hydrogen carbonate (NaHCO3). The reducing agent is preferably selected from the group consisting of sodium sulfite, hydrogen peroxide, sodium thiosulfate, and sodium bisulfite (or hydrogen sulfite) (NaHSO3). The absorbent in the absorption section may be one type or two or more types.

[0061] In the storage section 40 of the pyrolysis device 1, the concentration of impurities in the condensate is measured by analyzing the condensate while the pyrolysis gasification device 23 is operating stably. Figures 3(a), 3(b), and 3(c) are diagrams for explaining an example of operation in the storage section 40. Figure 4 is a diagram corresponding to Figures 3(a) to 3(c), and shows an example of use of each tank in chronological order.

[0062] As shown in FIG. 3(a), the first inlet valve V1a is open, the first outlet valve V1b is closed, and condensate is stored in the first tank 41 (at this time, the second inlet valve V2a is closed). As shown in FIG. 3(b), when a predetermined amount of condensate is stored in the first tank 41, the first tank 41 stops receiving liquid, and the first inlet valve V1a is closed. Meanwhile, the second inlet valve V2a is opened, and condensate is stored in the second tank 42. In the state shown in FIG. 3(b), the condensate is sampled from the first outlet S1 (see FIG. 2(a)), and impurities are measured using an analyzer (e.g., a gas chromatograph) or the like installed in a separate room.

[0063] After the analysis is completed, as shown in FIG. 3(c), the outlet-side first valve V1b is opened and the condensed liquid in the first tank 41 is discharged. The destination of the discharged liquid is determined to be either the purification section 50, the filling section 60, or the waste liquid storage section depending on the concentration of impurities. For this determination, two thresholds for the impurity concentration may be determined in advance. On the other hand, when a predetermined amount of condensed liquid is stored in the second tank 42, the second tank 42 stops receiving liquid, and the inlet-side second valve V2a is closed. The condensed liquid is collected from the second outlet S2 (see FIG. 2(a)), and the impurities are measured using an analyzer (e.g., a gas chromatograph) installed in a separate room. The destination of the condensed liquid that has completed the analysis in the second tank 42 is also determined in the same manner as above.

[0064] After that, both tanks are used to receive and store the liquid, analyze it, and then discharge the liquid.

[0065] As shown in FIG. 4, for example, the capacity (processing speed) of the pyrolysis gasification apparatus 23 and the capacity (processing speed) of the processing section related to the next process (e.g., the first purification tower 51 or the second purification tower 52 of the purification section 50) determine each process (time schedule) in a chronological order. FIG. 4 shows an example in which the capacities of both sections are approximately equal. That is, the time required to receive and store condensate in the first tank 41 (or the second tank 42) is approximately equal to the time required to discharge a predetermined amount of condensate, i.e., the time required for processing in the processing section related to the next process. The time required for analysis is shorter than the time required for receiving and storing condensate and the time required for processing in the processing section related to the next process. As shown in FIG. 4, condensate is discharged after the analysis results are known. Therefore, if one tank is being discharged and the other tank is being analyzed, the pyrolysis gasification apparatus 23 (pyrolysis section 20) must be stopped. Alternatively, when receiving and storing is performed in one of the tanks and analysis is performed in the other tank, it is necessary to stop the first purification column 51 or the second purification column 52 (purification section 50).

[0066] 4, if the capacity (processing speed) of the pyrolysis gasification apparatus 23 is greater than the capacity (processing speed) of the processing section related to the next step (for example, the first purification tower 51 or the second purification tower 52 of the purification section 50), continuous operation of the processing section related to the next step is possible, although this is not shown in the figure. Instead, the pyrolysis gasification apparatus 23 needs to be stopped a predetermined number of times per cycle.

[0067] Furthermore, if the capacity (processing speed) of the pyrolysis gasification apparatus 23 is smaller than the capacity (processing speed) of the processing section related to the next process (for example, the first purification tower 51 or the second purification tower 52 of the purification section 50), continuous operation of the pyrolysis gasification apparatus 23 is possible, although this is not shown in the drawings. Instead, the processing section related to the next process needs to be stopped a predetermined number of times per cycle.

[0068] Next, a storage unit according to a modified example will be described. Fig. 2(b) is a diagram showing a series version of storage unit 40X. Figs. 5(a), 5(b), and 5(c) are diagrams for explaining an example of operation of series version of storage unit 40X.

[0069] As shown in FIG. 2(b), a connecting pipe 46 connecting the first tank 41 and the second tank 42 connected in series and an intermediate valve 47 serving as a means for allowing or blocking the flow of condensate through the connecting pipe 46 are provided between the tanks. When the first tank 41 and the second tank 42 are arranged vertically side by side as shown in FIG. 2(b), the condensate in the first tank 41 is sent to the second tank 42 by opening the intermediate valve 47. In this case, the intermediate valve 47 serves as a liquid-sending means. Note that the description with reference to FIG. 5 will be given of a case in which the first tank 41 and the second tank 42 are arranged at the same height and a liquid-sending pump 48 serving as a liquid-sending means is provided in the connecting pipe 46 connecting the lower part of the first tank 41 and the upper part of the second tank 42. Note that even when multiple tanks are connected in series, the connection positions of the pipes to the tanks and the installation of the pumps or valves are not particularly limited. Any known configuration may be employed as long as the liquid inside can be freely sent.

[0070] As shown in FIG. 5(a), condensate is received in the first tank 41 and then transferred from the first tank 41 to the second tank 42 by the liquid transfer pump 48. The condensate is received and stored in the second tank 42. In this manner, when the second tank 42 is capable of storing condensate, the condensate always passes through the first tank 41. As shown in FIG. 5(b), when a predetermined amount of condensate is stored in the second tank 42, the second tank 42 stops receiving liquid and the liquid transfer pump 48 stops. If a valve is provided in the connecting pipe 46, the valve is also closed. The condensate is collected from the outlet S (see FIG. 2(b)), and impurities are measured using an analyzer (e.g., a gas chromatograph) installed in a separate room. The destination of the condensate that has completed analysis in the second tank 42 is determined in the same manner as in the parallel version described above.

[0071] In the state shown in FIG. 5(b), condensate is received and stored in the first tank 41. Once a predetermined amount of condensate has been stored in the first tank 41, provided that analysis and discharge of the condensate in the second tank 42 have been completed, the condensate is transferred from the first tank 41 to the second tank 42 by the liquid transfer pump 48, as shown in FIG. 5(c). Thereafter, the same operation (process) is repeated. Sampling and analysis are always performed in the second tank 42. When performing such an operation, it is preferable to provide an outlet S in the second tank 42 or the secondary piping P2.

[0072] According to the pyrolysis apparatus 1 of the above embodiment, the storage unit 40 has two or more tanks, and these tanks can be used appropriately. For example, condensate can be stored in one tank, and then analyzed for impurities. While waiting for the analysis results, the condensate can be stored in another tank. During the analysis, the condensate can be removed from the outlet, allowing for accurate measurement of the impurity concentration. By using the tanks appropriately, the downtime for stopping the pyrolysis unit can be eliminated (in which case continuous operation is possible) or can be shortened. Therefore, the pyrolysis gasification apparatus 23 can be operated stably, and the condensate can be sent to the appropriate process depending on the impurity concentration indicated by the analysis results.

[0073] The processing unit has at least one of a purification unit that purifies the condensate and a filling unit that fills the condensate for shipping, so that the condensate can be sent to an appropriate process, such as purifying the condensate or filling the condensate for shipping, depending on the concentration of impurities.

[0074] The treatment section has both a purification section for purifying the condensate and a filling section for filling the condensate for shipping, and the secondary piping is provided with a next-treatment switching means for switching the discharge destination of the condensate from the storage section to either the purification section or the filling section, thereby making it possible to appropriately select purification or filling (shipping) depending on the concentration of impurities.

[0075] Between the storage section and the processing section, a dehydration section, adsorption section, or absorption section is provided, which allows impurities to be removed while condensate is being discharged from the storage section (and, in some cases, while the upstream thermal decomposition section is operating).

[0076] A residue storage section is connected to the thermal decomposition section, which allows the residue generated in the thermal decomposition section to be discharged to the residue storage section without remaining in the thermal decomposition section, making it easier to prevent impurities derived from the residue from being mixed into the gas.

[0077] A partial condenser is installed between the thermal decomposition section and the condensation section, which allows the removal of substances contained in the thermal decomposition gas that have a boiling point higher than that of the target substance (also known as high-boiling impurities).

[0078] The storage unit has two or more tanks connected in parallel (see Figure 2(a)), and the storage unit is provided with a tank switching means for introducing condensate into one of the tanks, allowing storage and analysis to be performed alternately in the two tanks (see Figures 3(a) to 3(c)).

[0079] The storage unit has two or more tanks connected in series (see FIG. 2(b)), and is provided with a liquid delivery means for delivering the condensate to a downstream tank. This allows the downstream tank to be used exclusively for analysis, and the upstream tank to be used exclusively for receiving and storing the condensate (see FIGS. 5(a) to 5(c)).

[0080] Although the embodiments of the present disclosure have been described above, the present invention is not limited to the above embodiments. For example, as in the pyrolysis apparatus 1A shown in Fig. 6, the storage unit 40A may have three or more tanks connected in parallel. In this apparatus, the first tank 41, the second tank 42, and the third tank 45 receive, store, analyze, and discharge the liquid, thereby enabling stable operation of the pyrolysis gasification apparatus 23 and sending the condensate to an appropriate process depending on the concentration of impurities indicated by the analysis results.

[0081] The storage unit 40 may have three or more tanks connected in series. The storage unit 40 may have two or more tanks connected in parallel and one or more tanks connected in series with the tanks connected in parallel. When the multiple tanks of the storage unit 40 are connected in series, it is preferable that all of the tanks have similar storage capacities, but the tank connected to the next purification unit or filling unit may have a larger storage capacity than the other tanks connected to the storage unit 40, etc. [Explanation of symbols]

[0082] 1, 1A... thermal decomposition apparatus, 20... thermal decomposition section, 30... condensation section, 40, 40A, 40X... storage section, 50... purification section, 60... filling section, S, S1, S2... withdrawal port.

Claims

1. a thermal decomposition section that receives and thermally decomposes raw material resin; a condensation section for liquefying the pyrolysis gas discharged from the pyrolysis section; a storage section that stores the condensed liquid condensed in the condensation section, the storage unit has two or more tanks connected in parallel or in series, and at least one type of processing unit related to a next process is connected to the discharge side of the tanks; A pyrolysis apparatus, wherein an outlet for the condensate is provided in at least one of the storage section and a secondary pipe between the storage section and the processing section.

2. The pyrolysis apparatus according to claim 1 , wherein the processing section has at least one of a refining section that purifies the condensate and a filling section that fills the condensate for shipping.

3. 3. The pyrolysis apparatus according to claim 2, wherein the processing section has both a purification section that purifies the condensate and a filling section that fills the condensate for shipping, and the secondary piping is provided with a next-process switching means that switches the discharge destination of the condensate from the storage section to either the purification section or the filling section.

4. The pyrolysis apparatus according to any one of claims 1 to 3, wherein a dehydration section, an adsorption section, or an absorption section is provided between the storage section and the treatment section.

5. The pyrolysis device according to any one of claims 1 to 3, wherein a residue storage section is connected to the pyrolysis section.

6. The thermal decomposition apparatus according to any one of claims 1 to 3, wherein a partial condenser is provided between the thermal decomposition section and the condensation section.

7. the reservoir comprises two or more tanks connected in parallel; The pyrolysis apparatus according to any one of claims 1 to 3, wherein the storage section is provided with a tank switching means for introducing the condensate into one of the tanks.

8. the reservoir comprises two or more tanks connected in series; The pyrolysis apparatus according to any one of claims 1 to 3, wherein the storage section is provided with a liquid delivery means for delivering the condensate to a downstream tank.

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