(METH)acrylic polymer regeneration apparatus, (METH)acrylic polymer regeneration method, and method for producing monomer having (METH)acrylic group

Abstract

To provide a (meth)acrylic polymer regeneration apparatus, a (meth)acrylic polymer regeneration method, and a production method for a (meth)acrylic acid ester, each achieving superior efficiency in the utilization of energy consumed during recycling processing.SOLUTION: A (meth)acrylic polymer regeneration apparatus comprises a pyrolysis section that performs pyrolysis of a (meth)acrylic polymer to obtain a pyrolysis gas, a heat exchange section that transfers heat from the pyrolysis gas to a heat medium, and a transfer line that transfers the heat medium.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an apparatus for recycling a (meth)acrylic polymer, a method for recycling a (meth)acrylic polymer, and a method for producing a monomer having a (meth)acrylic group. [Background technology]

[0002] (Meth)acrylic polymers obtained by polymerizing monomers having a (meth)acrylic group have excellent transparency and weather resistance, and are therefore widely used as materials for components constituting automobile parts, signboards, display devices, etc.

[0003] Along with the recent rise in resource prices and growing awareness of environmental issues, there has been a growing trend to collect and recycle products (molded articles) containing (meth)acrylic polymers used for various applications as described above.

[0004] Methods for recycling molded articles containing (meth)acrylic polymers include, for example, material recycling, in which recovered molded articles are subjected to a molding process again to produce new molded articles; chemical recycling, in which recovered molded articles are thermally decomposed (depolymerized) to recover monomers having (meth)acrylic groups, and new molded articles are produced using these monomers; and thermal recycling, in which recovered molded articles are combusted and the resulting combustion energy is used as a direct heat source or as electricity converted by a generator.

[0005] (Meth)acrylic polymers are suitable for chemical recycling because the pyrolysis product, the monomer, can be recovered in high yield by heating at a relatively low temperature of about 300 to 500°C.

[0006] For example, Patent Document 1 describes a method for recovering a monomer having a (meth)acrylic group, which comprises heating a resin product containing a (meth)acrylic polymer in a heating furnace, cooling and liquefying the resulting gaseous pyrolysate, and then purifying the liquefied pyrolysate by distillation. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-321571 Summary of the Invention [Problem to be solved by the invention]

[0008] From the viewpoint of promoting the widespread use of a recycling system for (meth)acrylic polymers, one of the important issues is to improve the efficiency of energy consumption in the recycling process. In view of the above circumstances, an object of one embodiment of the present disclosure is to provide a (meth)acrylic polymer regeneration device, a (meth)acrylic polymer regeneration method, and a (meth)acrylic acid ester production method, which are excellent in the utilization efficiency of energy consumed in the recycling process. [Means for solving the problem]

[0009] Means for solving the above problems include the following embodiments. <1> a pyrolysis section that performs pyrolysis of a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange unit that transfers heat from the pyrolysis gas to a heat medium; a transfer line for transferring the heat medium. <2> The (meth)acrylic polymer supplied to the thermal decomposition section is further dried in a raw material drying section, and the transfer line transfers a heat medium to the raw material drying section. <1> The playback device described in <3> The capacity of the raw material drying section is four times or more the throughput per hour in the thermal decomposition section. <2> The playback device described in <4> The raw material drying section has a stirrer. <2> or <3> The playback device described in <5> The transfer line transfers the heat medium to the upper or lower part of the raw material drying section. <2> ~ <4> 10. The playback device according to claim 9, wherein: <6> the system further includes an undecomposed residue treatment section that treats undecomposed residue produced in the thermal decomposition section, and the transfer line transfers the heat medium to the undecomposed residue treatment section. <1> The playback device described in <7> The apparatus further includes a gas treatment unit for treating a pyrolysis gas produced in the pyrolysis unit, and the transfer line transfers a heat medium to the gas treatment unit. <1> The playback device described in <8> The transfer line circulates a heat transfer medium. <1> ~ <7> 10. The playback device according to claim 9, wherein: <9> The transfer line has a thermometer and a flow control valve. <1> ~ <8> 10. The playback device according to claim 9, wherein: <10> The transfer line is provided with a device for removing the liquid contained in the heat medium, the gas evaporated from the liquid, or foreign matter. <1> ~ <9> 10. The playback device according to claim 9, wherein: <11> The transfer line has a temperature adjusting unit that adjusts the temperature of the heat medium. <1> ~ <10> 10. The playback device according to claim 9, wherein: <12> The transfer line is insulated. <1> ~ <11> 10. The playback device according to claim 9, wherein: <13> The heat transfer medium is a gas or a liquid. <1> ~ <12> 10. The playback device according to claim 9, wherein: <14> a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; a transferring step of transferring the heat medium. <15> a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; and a transferring step of transferring the heat medium. [Effects of the Invention]

[0010] According to the present disclosure, there are provided a (meth)acrylic polymer regeneration device, a (meth)acrylic polymer regeneration method, and a (meth)acrylic acid ester production method, which are excellent in the efficiency of using energy consumed in the recycling process. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of a playback device. DETAILED DESCRIPTION OF THE INVENTION

[0012] First Embodiment The first embodiment of the present disclosure is a pyrolysis section that performs pyrolysis of a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange unit that transfers heat from the pyrolysis gas to a heat medium; and a transfer line for transferring the heat medium.

[0013] The recycling apparatus of this embodiment is used for chemical recycling in which a (meth)acrylic polymer supplied to the recycling apparatus is thermally decomposed to recover monomers. In chemical recycling of a (meth)acrylic polymer, the (meth)acrylic polymer is heated to cause thermal decomposition of the (meth)acrylic polymer. In conventional regeneration devices, the pyrolysis gas generated by heating the (meth)acrylic polymer is directly cooled and liquefied. In contrast, the regeneration device of this embodiment is equipped with a heat exchanger that transfers the heat of the pyrolysis gas to a heat medium and a transfer line that transfers the heat medium. Therefore, in the regeneration device of this embodiment, the heat received by the heat medium from the pyrolysis gas can be transferred to a desired location via the transfer line and used for a desired purpose.

[0014] The destination of the heat generated in the pyrolysis section is not particularly limited, and examples of the destination of the heat include a raw material drying section that dries the (meth)acrylic polymer supplied to the pyrolysis section, an undecomposed residue treatment section that treats the undecomposed residue generated in the pyrolysis section, and a gas treatment section that treats the pyrolysis gas generated in the pyrolysis section.

[0015] In the raw material drying section, which dries the (meth)acrylic polymer to be supplied to the pyrolysis section, liquid contained in the (meth)acrylic polymer is removed. Examples of liquid include water or organic solvents. The pyrolysis gas of the (meth)acrylic polymer obtained by chemical recycling may be contaminated with water or organic solvents accompanying the (meth)acrylic polymer supplied as a raw material. If the amount of liquid contained in the pyrolysis gas is large, for example, the amount of energy consumed in the process to remove the liquid increases. Therefore, it is desirable to remove as much liquid contained in the raw material as possible using the raw material drying section at a stage before it is supplied to the pyrolysis section. Furthermore, if the raw material contains a large amount of liquid, the liquefied components will adhere to the area around the raw material inlet of the pyrolysis section, causing the raw material to accumulate and creating the risk of clogging. Therefore, it is desirable to remove as much liquid as possible from the raw material before feeding it into the pyrolysis section. Furthermore, scrap materials may contain various types of resins. These resins may also contain resins that generate halogenated compounds through thermal decomposition. Halogenated compounds react with water to become strong acids, which can corrode and deteriorate equipment. Therefore, it is desirable to remove as much liquid as possible from the raw materials before feeding them into the thermal decomposition section. By transferring the heat generated in the pyrolysis section to the raw material drying section, the heat generated in the pyrolysis section can be used to dry the raw material.

[0016] In the undecomposed residue treatment section, which treats the undecomposed residue produced in the thermal decomposition section, the undecomposed residue produced together with the thermal decomposition gas in the thermal decomposition section is treated. By transferring the heat generated in the thermal decomposition section to the undecomposed residue treatment section, the heat generated in the thermal decomposition section can be utilized for treating the undecomposed residue. As a method for utilizing the heat for treating the undecomposed residue, which will be described later, there is mentioned temperature adjustment at least between the thermal decomposition section and the undecomposed residue treatment section or in the undecomposed residue treatment section.

[0017] The gas treatment section processes the pyrolysis gas produced in the pyrolysis section, specifically by liquefying (cooling) the pyrolysis gas and purifying the pyrolysis gas. By transferring the heat generated in the pyrolysis section to the gas treatment section, the heat generated in the pyrolysis section can be used to treat the pyrolysis gas. For example, one method of using the heat to treat the pyrolysis gas is to re-vaporize the liquefied pyrolysis product and purify it.

[0018] ((Meth)acrylic polymer) In the present disclosure, the term "(meth)acrylic polymer" refers to a polymer having structural units derived from a monomer having a (meth)acrylic group. In the present disclosure, "(meth)acrylic" includes acrylic, methacrylic, and combinations thereof.

[0019] The (meth)acrylic polymer may be a (meth)acrylic homopolymer or a (meth)acrylic copolymer. An example of the (meth)acrylic homopolymer is a (meth)acrylic homopolymer containing only monomer units derived from alkyl (meth)acrylate having an alkyl group having 1 to 4 carbon atoms. Examples of the (meth)acrylic copolymer include a (meth)acrylic copolymer in which the proportion of monomer units derived from alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is 85% by mass or more and less than 100% by mass, and the proportion of monomer units derived from other vinyl monomers copolymerizable with the monomer units derived from alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is more than 0% by mass and 15% by mass or less.

[0020] The "alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms" refers to a compound represented by, for example, CH2=C(CH3)COOR (wherein R is an alkyl group with 1 to 4 carbon atoms).

[0021] The vinyl monomer copolymerizable with an alkyl (meth)acrylate having an alkyl group with 1 to 4 carbon atoms is a monomer that is copolymerizable with an alkyl methacrylate having an alkyl group with 1 to 4 carbon atoms and has a vinyl group.

[0022] Examples of alkyl (meth)acrylates having an alkyl group of 1 to 4 carbon atoms include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, tert-butyl methacrylate, sec-butyl methacrylate, and isobutyl methacrylate. The alkyl methacrylate having an alkyl group of 1 to 4 carbon atoms is preferably methyl methacrylate.

[0023] Examples of vinyl monomers copolymerizable with alkyl (meth)acrylates having an alkyl group of 1 to 4 carbon atoms include methacrylate esters such as cyclohexyl methacrylate, benzyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, and monoglycerol methacrylate (excluding alkyl methacrylates having an alkyl group of 1 to 4 carbon atoms); methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, Examples of suitable monomers include acrylic acid esters such as 2-hydroxypropyl acrylate and monoglycerol acrylate; unsaturated carboxylic acids or anhydrides thereof such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride and itaconic anhydride; nitrogen-containing monomers such as acrylamide, methacrylamide, acrylonitrile, methacrylonitrile, diacetone acrylamide and dimethylaminoethyl methacrylate; epoxy group-containing monomers such as allyl glycidyl ether, glycidyl acrylate and glycidyl methacrylate; and styrene-based monomers such as styrene and α-methylstyrene.

[0024] The (meth)acrylic polymer may be polymethyl(meth)acrylate (PMMA or PMA), which is a polymer of methyl(meth)acrylate (MMA or MA).

[0025] The (meth)acrylic polymer supplied to the recycling device may be in the form of a molded product of the (meth)acrylic polymer. The type of molded product is not particularly limited and can be selected from known molded products such as cast molded products, extrusion molded products, and injection molded products.

[0026] The molded article of the (meth)acrylic polymer may consist of only the (meth)acrylic polymer, or may contain the (meth)acrylic polymer and a component different from the (meth)acrylic polymer. Examples of the component different from the (meth)acrylic polymer include polymers different from the (meth)acrylic polymer, such as polyvinyl chloride, polyolefin, and polyester, and additives. Examples of additives include fillers, colorants, ultraviolet inhibitors, and mold release agents.

[0027] The (meth)acrylic polymer supplied to the recycling device may be in the form of scrap or compressed material. In this disclosure, "scrap" refers to waste products collected after being used for a specific purpose, defective products and offcuts generated in the product manufacturing process, and pulverized waste products, defective products, and offcuts. "Compressed material" refers to a material obtained by compressing the material described as scrap. The scrap and compressed material may be adjusted in shape and size to be suitable for pyrolysis treatment.

[0028] The components included in the playback device of this embodiment will be described below.

[0029] (pyrolysis section) The regeneration device of this embodiment includes a thermal decomposition unit that thermally decomposes the (meth)acrylic polymer to convert it into a gaseous pyrolyzed product (pyrolysis gas). In the present disclosure, the thermal decomposition of a (meth)acrylic polymer means decomposing the (meth)acrylic polymer into monomers by heating.

[0030] As the thermal decomposition section, any device having a function of thermally decomposing a (meth)acrylic polymer can be used without any particular limitation. Processes used for the thermal decomposition of (meth)acrylic polymers include a molten metal bath process, a kneader process, a fluidized bed process, a microwave process, an extruder process, and the like.

[0031] The material of the thermal decomposition section is not particularly limited, and any known material can be used without any particular limitation. When the (meth)acrylic polymer supplied to the thermal decomposition section contains chlorine and water, hydrochloric acid may be generated by the reaction between the chlorine and water. Therefore, the (meth)acrylic polymer in the thermal decomposition section or the portion that comes into contact with the thermal decomposition gas is preferably made of a material that is highly corrosion-resistant. Examples of materials that are highly corrosion-resistant include Ti, Zr, Ta, and Hastelloy (registered trademark).

[0032] The conditions for carrying out the thermal decomposition of the (meth)acrylic polymer in the thermal decomposition section are not particularly limited, and can be set in consideration of the properties, composition, etc. of the (meth)acrylic polymer to be treated.

[0033] When a microwave process is used as the thermal decomposition method, for example, microwaves are irradiated from outside the reactor to thermally decompose the (meth)acrylic polymer. Unlike conventional heating processes, the use of microwaves allows energy to be applied directly and selectively to the target object at the speed of light. Plastics such as (meth)acrylic polymers generally have low microwave absorption capacity. For this reason, a component with high microwave absorption capacity may be added to the (meth)acrylic polymer to promote thermal decomposition.

[0034] From the viewpoint of the efficiency of the thermal decomposition process, the thermal decomposition section is preferably an extruder. In this disclosure, "extruder" refers to a device equipped with a mechanism that rotates a screw arranged inside a cylindrical member (cylinder) to melt raw materials fed from the upstream side of the cylinder and transport them downstream.

[0035] The type of extruder is not particularly limited, and a known twin-screw extruder or single-screw extruder can be used. From the viewpoint of efficiently carrying out the thermal decomposition of the (meth)acrylic polymer, the extruder is preferably a twin-screw extruder such as a twin-screw co-rotating extruder or a twin-screw counter-rotating extruder. As components of the extruder such as a cylinder and a screw, known components can be used without any particular limitation.

[0036] The pressure of the extruder is preferably 0.005 MPa to 1.5 MPa, more preferably 0.01 MPa to 0.3 MPa, from the viewpoint of preventing air from leaking into the system and pyrolysis gas from leaking out of the system.

[0037] From the viewpoint of thermal decomposition efficiency, the temperature inside the cylinder of the extruder can usually be set to 400° C. to 500° C. When the target of thermal decomposition is a pure (meth)acrylic polymer, the temperature is preferably 450° C. to 470° C.

[0038] From the viewpoint of stable operation of the extruder, the screw rotation speed of the extruder can usually be set to 500 rpm to 1500 rpm. When the target of thermal decomposition is a pure (meth)acrylic polymer, it is preferably 500 rpm to 1000 rpm.

[0039] The amount of (meth)acrylic polymer fed to the extruder varies depending on the scale of the extruder, but is usually 10 kg / hour to 5,000 kg / hour. For example, when the diameter of the extruder cylinder is 47 mm, the amount is preferably 40 kg / hour to 90 kg / hour.

[0040] (Heat exchange part) The regeneration device of this embodiment includes a heat exchanger that transfers heat from the pyrolysis gas generated in the pyrolysis section to a heat medium. In the heat exchange section, the method for transferring heat from the pyrolysis gas to the heat medium is not particularly limited. For example, the heat of the pyrolysis gas may be transferred to the heat medium using a known heat exchanger such as a plate heat exchanger, a shell-and-tube heat exchanger, a double-pipe heat exchanger, a coil heat exchanger, a spiral heat exchanger, or a regenerative heat exchanger. The heat transfer medium for transferring the heat of the pyrolysis gas may be either a gas or a liquid. The temperature of the pyrolysis gas before heat is transferred to the heat medium in the heat exchange section may be, for example, 300°C to 400°C. The temperature of the pyrolysis gas after heat is transferred to the heat medium in the heat exchange section may be, for example, 100°C to 350°C. The heat exchanger may be an independent device or may be integrated with another device (for example, a cooler included in the gas processing unit). That is, at least a portion of the components contained in the pyrolysis gas may be liquefied when heat is transferred to the heat medium in the heat exchanger.

[0041] (Transfer line) The regeneration device of this embodiment includes a transfer line that transfers the heat medium that has received heat from the pyrolysis gas in the heat exchanger. There are no particular limitations on the destination of the heat medium through the transfer line. For example, the heat medium may be transferred to a portion of the regeneration device, such as a raw material drying section, an undecomposed residue treatment section, or a gas treatment section, which will be described later. The transfer line may also transfer the heat transfer medium to equipment that does not constitute a regeneration device, such as a boiler system or a power generation system. The heat transfer medium may be transferred to one location or two or more locations through the transfer line.

[0042] The transfer line may circulate the heat medium. Specifically, the transfer line may include a line for transferring the heat medium from the heat exchange unit to the transfer destination, and a line for transferring the heat medium from the transfer destination to the heat exchange unit. The transfer line may have a device for promoting the transfer of the heat transfer medium, such as an air blower or a pump.

[0043] The transfer line may have a thermometer and a flow rate adjusting valve. By having the thermometer and the flow rate adjusting valve on the transfer line, it is possible to transfer the heat medium at a desired temperature and at a desired flow rate to the transfer destination.

[0044] The transfer line may have a temperature adjusting unit that adjusts the temperature of the heat medium. By having the temperature adjusting unit in the transfer line, the temperature of the heat medium can be adjusted to a desired temperature. When the transfer line transfers a heat medium to the raw material drying section, the temperature of the heat medium may be adjusted to a range of 60°C to 120°C. When the transfer line transfers a heat medium to the uncracked residue treatment section or the gas treatment section, the temperature of the heat medium may be adjusted to a range of 150° C. to 300° C. The temperature of the heat medium can be appropriately adjusted, for example, to a temperature range in which the uncracked residue is melted.

[0045] The transfer line may be thermally insulated. By insulating the transfer line, the heat received by the heat transfer medium from the pyrolysis gas can be efficiently transferred to the destination. Specific examples of the configuration of an insulated transfer line include a configuration in which a heat insulating material is arranged around the piping that transfers the heat transfer medium, and a configuration in which the piping that transfers the heat transfer medium has a double structure and the outer layer has a thermal insulating function.

[0046] The transfer line may have a device for removing liquids such as water or organic solvents contained in the heat medium, vaporized gases, or foreign matter. By having a device for removing liquids, gases, or foreign matter in the transfer line, it is possible to remove liquids, vaporized gases, or foreign matter mixed in the heat medium, allowing the heat medium to be used continuously. As the device for removing liquids, gases, or foreign matter, known means such as adsorbents, absorbents, metal catalysts, and filters can be used in combination as needed without any particular limitation.

[0047] (Raw material drying section) The recycling device of this embodiment may include a raw material drying section that dries and removes liquid (e.g., water, organic solvents, etc.) contained in the (meth)acrylic polymer supplied to the pyrolysis section. Hereinafter, the treatment of removing the liquid contained in the (meth)acrylic polymer by drying will also be referred to as "drying treatment of the (meth)acrylic polymer." In the present disclosure, the drying treatment of a (meth)acrylic polymer includes a treatment for partially removing the liquid contained in the (meth)acrylic polymer and a treatment for completely removing the liquid contained in the (meth)acrylic polymer.

[0048] The liquid content of the (meth)acrylic polymer before the drying treatment is not particularly limited. For example, if the water liquid content of the (meth)acrylic polymer before the drying treatment is 5% by mass or more, 10% by mass or more, or 15% by mass or more, the effect of the drying treatment is greater. When the liquid is water, the liquid content is the water content. The drying treatment of the (meth)acrylic polymer is preferably carried out so that the liquid content of the (meth)acrylic polymer after the drying treatment is 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably 0.1% by mass or less.

[0049] When drying the (meth)acrylic polymer, evaporation of the liquid contained in the (meth)acrylic polymer may be promoted by adjusting one or more of the conditions of the environment surrounding the (meth)acrylic polymer, such as temperature, relative humidity, airflow, and atmospheric pressure. From the viewpoint of easily controlling the amount of liquid after drying the (meth)acrylic polymer, a method that adjusts at least one of the temperature or airflow is preferred, and a method that adjusts both the temperature and airflow may also be adopted. In order to accelerate the drying of the (meth)acrylic polymer, the (meth)acrylic polymer may be heated. In this case, the (meth)acrylic polymer may be heated using a heat medium transferred to the raw material drying section via a transfer line. From the viewpoint of efficient drying of the raw materials, the transfer line preferably transfers the heat medium to the upper or lower part of the raw material drying section, and more preferably to the lower part. In this disclosure, the lower part of the raw material drying section refers to the part that comes into contact with the raw materials in the direction of gravity (for example, the bottom of a container that stores the raw materials, the bottom of a conveyor that transports the raw materials, etc.). From the viewpoint of efficiently drying the raw material, the raw material drying section may be equipped with a stirrer.

[0050] In order to sufficiently dry the raw material, the drying time is preferably 4 hours or more. The capacity of the raw material drying section may be 4 times or more the throughput per hour in the thermal decomposition section.

[0051] From the viewpoint of efficient drying of the raw material, it is preferable to bring the raw material into contact with a heat transfer medium in the raw material drying section. Specifically, it is preferable to bring the heat transfer medium discharged from an opening of the transfer line into contact with the raw material. The contact between the raw material and the heat transfer medium may be carried out in a closed space or in an open space. When the raw material is brought into contact with the heat transfer medium, the heat transfer medium after contacting the raw material may or may not be recovered by a transfer line.

[0052] <Examples of raw material drying> Below, specific examples of how the heat transfer medium is transferred to the raw material drying section via a transfer line are described, but the embodiments of the present invention are not limited to the following examples, and appropriate design changes can be made so as to obtain similar effects.

[0053] When the heat medium is a gas and the transfer line transfers the heat medium to the upper part of the raw material drying section, the heat medium may be guided through the transfer line and brought into contact with the raw material. For example, the heat medium may be sprayed onto the raw material. In this case, the sprayed heat medium may be recovered or released to the atmosphere. When the heat medium is a gas and the transfer line transfers the heat medium to the lower part of the raw material drying section, the following form (1) or (2) may be used. (1) A form in which the heat transfer medium is drawn out from a transfer line and brought into contact with the raw material (2) A transfer line is placed in the raw material drying section. In the case of (1), the heat transfer medium may be recovered or may be released to the atmosphere. In the case of (2), for example, a method in which the transfer line is arranged along the peripheral wall of the raw material drying section to heat the drying section or the raw material in the drying section, or a method in which the transfer line is arranged so as to come into contact with the raw material to heat the raw material, may be mentioned. In this case, the heat insulation material on the transfer line may be appropriately adjusted, for example, not provided or provided to the extent that efficient drying is possible.

[0054] When the heat medium is a liquid and the transfer line transfers the heat medium to the upper part of the raw material drying section, the transfer line may be arranged in the raw material drying section. Examples of such an arrangement include a method in which the transfer line is arranged along the peripheral wall of the raw material drying section to heat the drying section or the raw materials in the drying section, and a method in which the transfer line is arranged so as to come into contact with the raw materials to heat the raw materials. In this case, the insulation on the transfer line may be appropriately adjusted, for example, by not providing insulation or by providing insulation to the extent that efficient drying is possible. When the heat medium is a liquid and the transfer line transfers the heat medium to the lower part of the raw material drying section, the same configuration as when the heat medium is transferred to the upper part can be mentioned.

[0055] (Gas processing unit) The regeneration device of the present disclosure may include a gas treatment section that treats the pyrolysis gas generated in the pyrolysis section. The method for treating the pyrolysis gas is not particularly limited and can be selected from known methods. As a means for treating the pyrolysis gas, known means such as a cooling section for cooling and liquefying the pyrolysis gas, a purification section for increasing the purity of the monomer having a (meth)acrylic group contained in the pyrolysis product gas, and a tank for storing the monomer having a (meth)acrylic group liquefied by cooling can be used in combination as needed, without any particular limitation. The gas treatment section preferably includes at least one selected from the group consisting of a cooling section that cools the pyrolysis gas and a purification section that purifies the pyrolysis gas.

[0056] <Example of a gas processing unit> The following describes a specific example of a configuration in which the heat transfer medium is transferred to the gas treatment section, specifically the purification section, via a transfer line. The embodiment of the present invention is not limited to the following example, and appropriate design changes can be made to obtain similar effects.

[0057] When the heat transfer medium is transferred to the gas treatment section, particularly the purification section, the following form (1) or (2) may be adopted. (1) Heating the composition to be refined in the refining section (2) Heating the refining section An example of the form (1) is a method in which a part of the composition to be refined in the refining section is extracted from the refining section, introduced into the refining section from the top thereof, and circulated in a device or pipe, and the device or pipe is heated with a heat medium. In the form (2), a transfer line is arranged along the outer peripheral wall of the refining section to heat the refining section. In either case, the heat insulating material on the transfer line may be appropriately adjusted, for example, not provided or provided to the extent that efficient drying is possible.

[0058] (Raw material supply department) The recycling device of the present disclosure may further include a raw material supply section that supplies a (meth)acrylic polymer as a raw material to the pyrolysis section. The method for supplying the raw materials is not particularly limited and can be selected from known methods. The raw material supply unit may include a processing device for processing the raw material, such as crushing the raw material, a detector for detecting foreign matter contained in the raw material, a measuring device for controlling the amount of raw material fed in, and the like. The raw material supply unit may be integrated with the raw material drying unit described above, or may be an independent device from the raw material drying unit. When the raw material supply unit is an independent device, the raw material supply unit may be provided before (upstream) the raw material drying unit or after (downstream) the raw material drying unit.

[0059] (Impurity gas treatment unit) The regeneration device of the present disclosure may include an impurity gas treatment section that treats the impurity gas generated in the thermal decomposition section. In the present disclosure, the term "impurity gas" refers to components other than the monomer having a (meth)acrylic group contained in the pyrolysis gas generated in the pyrolysis section. Examples of the impurity gas include chlorine gas and water vapor. The method for treating the impurity gas is not particularly limited and can be selected from known methods. As a means for treating impurity gases, known means such as adsorbents, absorbents, metal catalysts, filters, etc. can be used without any particular limitation, and can be combined as necessary. Specific examples of the adsorbent include alumina, calcium oxide, calcium carbonate, iron oxide, iron hydroxide, carbon, zeolite, a complex of iron oxide and / or metallic iron with carbon, a complex of calcium oxide and carbon, and a complex of iron oxide and / or metallic iron with calcium carbonate and / or calcium oxide and carbon. 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 bicarbonate (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 adsorbent or absorbent used in the impurity gas treatment section may be one type or two or more types.

[0060] From the viewpoint of increasing the efficiency of removing impurity gases from pyrolysis gases, it is preferable that the adsorbent or absorbent has a large contact area with the pyrolysis gas, and from this viewpoint, the adsorbent or absorbent is preferably in particulate form.

[0061] (Division part) The regeneration device of the present disclosure may further include a partial condensation section that condenses at least a portion of the impurities contained in the pyrolysis gas. The partial condensation section may, for example, cool the pyrolysis gas to a temperature equal to or higher than the condensation point of the monomer having a (meth)acrylic group and lower than the condensation point of the impurities contained in the pyrolysis gas. The regeneration device is provided with a partial condensation section, which makes it possible to selectively condense, for example, impurities contained in the pyrolysis gas discharged from the pyrolysis section and which condense at a temperature higher than that of the monomer containing a (meth)acrylic acid ester as a main component (hereinafter also referred to as high condensation point impurities). In other words, the partial condensation section can convert the pyrolysis gas into a state (mist state) in which droplets formed by condensation of impurities are present in a gas containing a monomer having a (meth)acrylic group.

[0062] The temperature of the pyrolysis gas after being cooled by the partial condensation section can be set depending on the types of components contained in the pyrolysis gas. For example, when the pyrolysis gas contains methyl (meth)acrylate as a monomer having a (meth)acrylic group, the temperature of the pyrolysis gas after being cooled by the partial condensation section is preferably 100°C to 420°C, more preferably 100°C to 300°C, and even more preferably 100°C to 200°C.

[0063] The impurities condensed from the pyrolysis gas after being cooled in the partial condensation section may be removed. The method for removing the impurities is not particularly limited, and can be carried out by a known method. For example, impurities contained in the pyrolysis gas in the form of droplets may be collected by a collection device such as a demister or a gravity sedimentation classifier.

[0064] (Residue storage area) The regeneration device of the present disclosure may further include a residue storage section that stores the residue discharged from the pyrolysis section. The method for storing the residue is not particularly limited and can be selected from known methods. The residue storage unit may include a processing device or the like that processes the residue into a disposable state. The method for storing the residue is not particularly limited and can be selected from known methods.

[0065] <Example of residue storage area> Specific examples of transfer of the heat transfer medium to the residue storage section through a transfer line are described below. The embodiments of the present invention are not limited to the following examples, and appropriate design changes can be made to obtain similar effects.

[0066] When the heat transfer medium is transferred to the residue storage section, the following form (1) or (2) may be used. (1) Heating the area from the residue outlet of the pyrolysis section to the residue storage section (2) Temperature control of the residue storage area by heating or keeping it warm Examples of the forms (1) and (2) include adjusting the temperature of the undecomposed residue to a temperature above the melting point and below the ignition point when transferring or storing the undecomposed residue in a residue storage area, and keeping the undecomposed residue at this temperature. As an example of the method (1), a transfer line is arranged along the peripheral wall of the area (e.g., piping) between the residue discharge port of the thermal decomposition section and the residue storage section, and the area is heated or kept warm. In the case of (2), a transfer line is arranged along the peripheral wall of the residue storage section, and the residue storage section is heated or kept warm. In either case, the heat insulating material on the transfer line may be appropriately adjusted, for example, not provided or provided to the extent that efficient drying is possible.

[0067] Second Embodiment A second embodiment of the present disclosure is a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; and a transferring step of transferring the heat medium. The playback method of this embodiment may be implemented using the playback device of the first embodiment.

[0068] The details and preferred aspects of the pyrolysis step, heat exchange step and transfer step are the same as the details and preferred aspects of the pyrolysis section, heat exchange section and transfer line in the regeneration apparatus of the first embodiment.

[0069] The regeneration method of the present embodiment may further include a raw material drying step of drying the (meth)acrylic polymer pyrolyzed in the pyrolysis step. In this case, the heat medium transferred in the transfer step may be used to dry the (meth)acrylic polymer.

[0070] The regeneration method of this embodiment may further include a residue treatment step of treating the uncracked residue produced in the pyrolysis step. In this case, the heat medium transferred in the transfer step may be used to treat the uncracked residue.

[0071] The regeneration method of the present embodiment may further include a gas treatment step of treating the pyrolysis gas produced in the pyrolysis step. In this case, the heat medium transferred in the transfer step may be used to treat the pyrolysis gas.

[0072] The regeneration method of this embodiment may further include a raw material supply step for supplying a (meth)acrylic polymer, an impurity gas treatment step for treating impurity gas generated in the pyrolysis section, and / or a partial condensation step for condensing at least a portion of the impurities contained in the pyrolysis gas. Details and preferred aspects of the raw material supply step, partial condensation step, and impurity gas treatment step are the same as those of the raw material supply section, partial condensation section, and impurity gas treatment section in the regeneration apparatus of the first embodiment.

[0073] According to the recycling method of the present embodiment, the (meth)acrylic polymer contained in the raw material is recycled into a monomer having a (meth)acrylic group by thermal decomposition. The reproduced monomer having a (meth)acrylic group is used, for example, as a raw material monomer for a (meth)acrylic polymer.

[0074] The monomer having a (meth)acrylic group obtained by the recycling method of this embodiment may contain methyl (meth)acrylate. The monomer having a (meth)acrylic group obtained by the recycling method of this embodiment may be a mixture of methyl (meth)acrylate and unavoidably contained monomers other than methyl (meth)acrylate (e.g., methyl isobutyrate, methyl propionate, methyl acrylate, etc.). In this case, the monomers other than methyl (meth)acrylate in the mixture may or may not be removed.

[0075] <Third embodiment> A third embodiment of the present disclosure is a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; and a transferring step of transferring the heat medium. The manufacturing method of this embodiment may be carried out using the regenerating apparatus of the first embodiment.

[0076] The details and preferred aspects of the pyrolysis step, heat exchange step and transfer step are the same as the details and preferred aspects of the pyrolysis section, heat exchange section and transfer line in the regeneration apparatus of the first embodiment.

[0077] The production method of this embodiment may further include a raw material drying step of drying the (meth)acrylic polymer pyrolyzed in the pyrolysis step. In this case, the heat medium transferred in the transfer step may be used to dry the (meth)acrylic polymer.

[0078] The production method of this embodiment may further include a residue treatment step of treating the uncracked residue produced in the pyrolysis step. In this case, the heat medium transferred in the transfer step may be used to treat the uncracked residue.

[0079] The manufacturing method of this embodiment may further include a gas treatment step of treating the pyrolysis gas produced in the pyrolysis step. In this case, the heat medium transferred in the transfer step may be used to treat the pyrolysis gas.

[0080] The production method of this embodiment may further include a raw material supplying step of supplying a (meth)acrylic polymer, an impurity gas treatment step of treating an impurity gas generated in the pyrolysis section, and / or a partial condensation step of condensing at least a portion of the impurities contained in the pyrolysis gas. Details and preferred aspects of the raw material supply step, partial condensation step, and impurity gas treatment step are the same as those of the raw material supply section, partial condensation section, and impurity gas treatment section in the regeneration apparatus of the first embodiment.

[0081] According to the production method of this embodiment, a monomer having a (meth)acrylic group is obtained as a thermal decomposition product of a (meth)acrylic polymer contained in the raw material. The monomer having a (meth)acrylic group obtained as a pyrolyzate is used, for example, as a raw material monomer for a (meth)acrylic polymer.

[0082] The monomer having a (meth)acrylic group obtained by the production method of this embodiment is used, for example, as a raw material monomer for a (meth)acrylic polymer.

[0083] The monomer having a (meth)acrylic group obtained by the production method of this embodiment may contain methyl (meth)acrylate. The monomer having a (meth)acrylic group obtained by the production method of this embodiment may be a mixture of methyl (meth)acrylate and a monomer other than methyl (meth)acrylate that may be inevitably contained (e.g., methyl isobutyrate, methyl propionate, methyl acrylate, etc.). In this case, the monomer other than methyl (meth)acrylate in the mixture may or may not be removed.

[0084] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. Note that the components shown in each drawing can be modified without departing from the scope of the present disclosure.

[0085] 1 is a diagram schematically illustrating an example of the configuration of a recycling apparatus according to Embodiment 1. Arrows in the diagram indicate the flow direction of the (meth)acrylic polymer recycling treatment or the transfer direction of the heat medium. The regeneration device 100 shown in FIG. 1 includes a raw material drying section 1, a thermal decomposition section 2, a heat exchange section 3, a gas treatment section 4, and an undecomposed residue treatment section 5. The regeneration apparatus 100 shown in FIG. 1 further includes a transfer line A for transferring the heat medium from the heat exchange section 3 to the raw material drying section 1, and a transfer line B for transferring the heat medium from the raw material drying section 1 to the heat exchange section 3.

[0086] 1, the transfer line includes transfer line A that transfers the heat medium from heat exchange section 3 to raw material drying section 1, and transfer line B that transfers the heat medium from raw material drying section 1 to heat exchange section 3 (i.e., the transfer line is of a circulating type), but the regeneration device of the present disclosure is not limited to this. For example, the transfer line may consist only of transfer line A that transfers the heat medium from heat exchange section 3 to raw material drying section 1.

[0087] 1, the transfer line is provided between the heat exchange section 3 and the raw material drying section 1, but the regeneration device of the present disclosure is not limited to this. For example, the transfer line may be provided between the heat exchange section 3 and the gas treatment section 4, or between the heat exchange section 3 and the undecomposed residue treatment section 5. [Explanation of symbols]

[0088] 100 playback equipment 1 Raw material drying section 2 Pyrolysis section 3 Heat exchange section 4 Gas Processing Section 5 Undecomposed residue treatment section A, B transfer lines

Claims

1. a pyrolysis section for pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange unit that transfers heat from the pyrolysis gas to a heat medium; a transfer line for transferring the heat medium.

2. 2. The regeneration apparatus according to claim 1, further comprising a raw material drying section for drying the (meth)acrylic polymer to be supplied to the thermal decomposition section, wherein the transfer line transfers a heat medium to the raw material drying section.

3. 3. The regeneration apparatus according to claim 2, wherein the capacity of the raw material drying section is four times or more the throughput per hour of the thermal decomposition section.

4. The regeneration apparatus according to claim 2 , wherein the raw material drying section has an agitator.

5. The regeneration apparatus according to claim 2 , wherein the transfer line transfers the heat medium to an upper or lower portion of the raw material drying section.

6. The regeneration apparatus according to claim 1 , further comprising an undecomposed residue treatment section that treats undecomposed residue produced in the thermal decomposition section, wherein the transfer line transfers the heat medium to the undecomposed residue treatment section.

7. The regeneration apparatus according to claim 1 , further comprising a gas treatment section for treating a pyrolysis gas produced in the pyrolysis section, wherein the transfer line transfers the heat medium to the gas treatment section.

8. The regeneration apparatus according to any one of claims 1 to 7, wherein the transfer line circulates a heat medium.

9. 8. The regeneration apparatus according to claim 1, wherein the transfer line has a thermometer and a flow rate adjusting valve.

10. 8. The regeneration apparatus according to claim 1, wherein the transfer line is provided with a device for removing liquid contained in the heat medium, gas resulting from evaporation of the liquid, or foreign matter.

11. 8. The regenerating apparatus according to claim 1, wherein the transfer line has a temperature adjusting section for adjusting the temperature of the heat medium.

12. 8. The regeneration apparatus according to claim 1, wherein the transfer line is heat-insulated.

13. 8. The regenerating apparatus according to claim 1, wherein the heat transfer medium is a gas or a liquid.

14. a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; a transferring step of transferring the heat medium.

15. a pyrolysis step of pyrolyzing a (meth)acrylic polymer to obtain a pyrolysis gas; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; and a transferring step of transferring the heat medium.

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