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

Abstract

The present invention addresses the problem of providing: a (meth)acrylic polymer regeneration device having excellent utilization efficiency of energy consumed in recycling treatment; a (meth)acrylic polymer regeneration treatment method; and a method for producing a (meth)acrylic acid ester.　The present invention relates to a (meth)acrylic polymer regeneration device comprising a thermal decomposition unit that thermally decomposes a (meth)acrylic polymer to obtain pyrolysis gas, a heat exchange unit that transfers heat from the pyrolysis gas to a heat medium, and a transfer line that transfers the heat medium.

Description

(Meth)acrylic polymer recycling device, (meth)acrylic polymer recycling method, and (meth)acrylic group-containing monomer manufacturing method

[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.

[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 (recycle) products (molded articles) containing (meth)acrylic polymers used for various applications as described above.

[0004] Methods for recycling molded articles containing a (meth)acrylic polymer 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 pyrolyzed monomers can be recovered in high yield by heating at a relatively low temperature of about 300°C 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 to obtain a gaseous pyrolysate, cooling and liquefying the resulting pyrolysate, and then purifying the liquefied pyrolysate by distillation.

[0007] Japanese Patent Application Laid-Open No. 2003-321571

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

[0009] Means for solving the above problems include the following embodiments. <1> A regeneration device for a (meth)acrylic polymer, comprising: a pyrolysis section that thermally decomposes 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. <2> The regeneration device according to <1>, further comprising a raw material drying section that dries the (meth)acrylic polymer to be supplied to the pyrolysis section, wherein the transfer line transfers the heat medium to the raw material drying section. <3> The regeneration device according to <2>, wherein the capacity of the raw material drying section is four times or more the hourly throughput of the pyrolysis section. <4> The regeneration device according to <2> or <3>, wherein the raw material drying section has a stirrer. <5> The regeneration device according to any one of <2> to <4>, wherein the transfer line transfers the heat medium to an upper or lower part of the raw material drying section. <6> The regeneration device according to <1>, further comprising an uncracked residue treatment section that treats uncracked residue produced in the thermal decomposition section, and the transfer line transfers a heat medium to the uncracked residue treatment section. <7> The regeneration device according to <1>, further comprising a gas treatment section that treats pyrolysis gas produced in the thermal decomposition section, and the transfer line transfers a heat medium to the gas treatment section. <8> The regeneration device according to any one of <1> to <7>, wherein the transfer line circulates a heat medium. <9> The regeneration device according to any one of <1> to <8>, wherein the transfer line has a thermometer and a flow control valve. <10> The regeneration device according to any one of <1> to <9>, wherein the transfer line is equipped with a device for removing a liquid contained in the heat medium, a gas evaporated from the liquid, or foreign matter. <11> The regeneration device according to any one of <1> to <10>, wherein the transfer line has a temperature control section that adjusts the temperature of the heat medium. <12> The regeneration device according to any one of <1> to <11>, wherein the transfer line is thermally insulated. <13> The regeneration device according to any one of <1> to <12>, wherein the heat medium is a gas or a liquid. <14> A method for regenerating a (meth)acrylic polymer, comprising: 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 transport step of transporting the heat medium.<15> A method for producing a monomer having a (meth)acrylic group, comprising: 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 transfer step of transferring the heat medium.

[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.

[0011] FIG. 1 is a schematic diagram showing an example of the configuration of a playback device.

[0012] First Embodiment A first embodiment of the present disclosure is a (meth)acrylic polymer regeneration device including: 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 transports the heat medium.

[0013] The regeneration device of this embodiment is used in chemical recycling, in which a (meth)acrylic polymer supplied to the regeneration device is pyrolyzed to recover monomers. In chemical recycling of a (meth)acrylic polymer, the (meth)acrylic polymer is heated to cause pyrolysis 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 transports 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 to be 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] The raw material drying section, which dries the (meth)acrylic polymer supplied to the pyrolysis section, removes liquid contained in the (meth)acrylic polymer. Examples of such liquid include water and organic solvents. The pyrolysis gas of the (meth)acrylic polymer obtained through chemical recycling may be contaminated with water or organic solvents accompanying the (meth)acrylic polymer supplied as a raw material. If the pyrolysis gas contains a large amount of liquid, for example, the amount of energy consumed in the process of removing the liquid increases. Therefore, it is desirable to remove as much liquid as possible from the raw material using the raw material drying section before supplying it to the pyrolysis section. Furthermore, if the raw material contains a large amount of liquid, liquefied components may adhere to the raw material inlet of the pyrolysis section, causing the raw material to accumulate and potentially causing blockage. Therefore, it is desirable to remove as much liquid as possible from the raw material before supplying it to the pyrolysis section. Furthermore, raw materials recovered as scrap may contain various types of resins. These resins may also contain resins that generate halogen-based compounds upon pyrolysis. Halogen-based compounds react with water to form strong acids, which may corrode and deteriorate equipment. Therefore, it is desirable to remove as much liquid as possible from the raw material before feeding it into the pyrolysis 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] The undecomposed residue treatment section, which treats the undecomposed residue produced in the thermal decomposition section, treats the undecomposed residue produced together with the pyrolysis gas in the thermal decomposition section. 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 used to treat the undecomposed residue. Methods for using the heat to treat the undecomposed residue include temperature adjustment at least between the thermal decomposition section and the undecomposed residue treatment section or in the undecomposed residue treatment section, as will be described later.

[0017] The pyrolysis gas produced in the pyrolysis section is treated in the gas treatment section. Specific examples of pyrolysis gas treatment include liquefaction (cooling) of the pyrolysis gas and purification of 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. One example of a method for utilizing heat in the treatment of pyrolysis gas is a process of re-vaporizing the liquefied pyrolysis product and purifying it.

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

[0019] The (meth)acrylic polymer may be a (meth)acrylic homopolymer or a (meth)acrylic copolymer. Examples of (meth)acrylic homopolymers include (meth)acrylic homopolymers containing only monomer units derived from alkyl (meth)acrylates having an alkyl group with 1 to 4 carbon atoms. Examples of (meth)acrylic copolymers include (meth)acrylic copolymers in which the proportion of monomer units derived from alkyl (meth)acrylates having an alkyl group with 1 to 4 carbon atoms is 85% by mass or more but 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)acrylates having an alkyl group with 1 to 4 carbon atoms is more than 0% by mass but not more than 15% by mass.

[0020] The term "(meth)acrylic acid alkyl having an alkyl group having 1 to 4 carbon atoms" refers to, for example, CH ２ =C(CH ３ )COOR (wherein R is an alkyl group having 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 which is copolymerizable with an alkyl methacrylate having an alkyl group with 1 to 4 carbon atoms and which 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 methacrylic acid 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 such as acrylic acid, methacrylic acid, maleic acid, itaconic acid, maleic anhydride and itaconic anhydride, or acid anhydrides thereof; 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 be composed of only the (meth)acrylic polymer, or may contain the (meth)acrylic polymer and a component other than the (meth)acrylic polymer. The component other than the (meth)acrylic polymer may include a polymer other than the (meth)acrylic polymer, such as polyvinyl chloride, polyolefin, or polyester, or an additive. The additive may include a filler, a colorant, an ultraviolet inhibitor, or a mold release agent.

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

[0030] The thermal decomposition section can be any device capable of thermally decomposing a (meth)acrylic polymer, and processes that can be used for the thermal decomposition of a (meth)acrylic polymer include the molten metal bath process, kneader process, fluidized bed process, microwave process, and extruder process.

[0031] The material of the thermal decomposition section is not particularly limited, and known materials can be used without particular limitation. When the (meth)acrylic polymer supplied to the thermal decomposition section contains chlorine and water, hydrochloric acid may be generated by reaction between the chlorine and water. Therefore, the part of the thermal decomposition section that comes into contact with the (meth)acrylic polymer or its pyrolysis gas is preferably made of a material with excellent corrosion resistance. Examples of materials with excellent corrosion resistance 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 the outside of 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 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 pyrolysis process, the pyrolysis section is preferably an extruder. In the present disclosure, the term "extruder" refers to a device having a mechanism for rotating a screw disposed inside a cylindrical member (cylinder) to melt raw materials introduced from the upstream side of the cylinder and transport the melted raw materials to the downstream side.

[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. Known configurations can be used for components such as a cylinder and a screw constituting the extruder without any particular limitations.

[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 the efficiency of pyrolysis, the temperature inside the cylinder of the extruder can usually be set to 400° C. to 500° C. When the target of pyrolysis 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, the rotation speed is preferably 500 rpm to 1000 rpm.

[0039] The amount of the (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 cylinder of the extruder is 47 mm, the amount is preferably 40 kg / hour to 90 kg / hour.

[0040] (Heat Exchange Section) The regeneration device of this embodiment includes a heat exchange section. The heat exchange section transfers heat from the pyrolysis gas generated in the pyrolysis section to a heat medium. The method for transferring heat from the pyrolysis gas to the heat medium in the heat exchange section 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 multi-tube heat exchanger, a double-tube heat exchanger, a coil heat exchanger, a spiral heat exchanger, or a regenerative heat exchanger. Either a gas or a liquid may be used as the heat medium for transferring the heat of the pyrolysis gas. The temperature of the pyrolysis gas before transferring heat 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 transferring heat to the heat medium in the heat exchange section may be, for example, 100°C to 350°C. The heat exchange section may be an independent device or may be integrated with another device (for example, a cooler included in the gas processing section). That is, at least a part of the components contained in the pyrolysis gas may be liquefied when heat is transferred to the heat medium in the heat exchange section.

[0041] (Transfer Line) The regeneration device of this embodiment includes a transfer line. The transfer line transfers the heat medium that has received heat from the pyrolysis gas in the heat exchange section. There are no particular restrictions on the destination of the heat medium transferred by 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 uncracked residue treatment section, or a gas treatment section, which will be described later. The transfer line may also transfer the heat medium to a device that does not constitute the regeneration device, such as a boiler facility or a power generation facility. The destination of the heat medium transferred by the transfer line may be one location or two or more locations.

[0042] The transfer line may be one that circulates the heat medium. Specifically, the transfer line may include a line that transfers the heat medium from the heat exchange unit to the transfer destination, and a line that transfers 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 medium. Examples of the device for promoting the transfer of the heat medium include an air supply unit (blower) and 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 adjustment unit that adjusts the temperature of the heat medium. By having the transfer line have a temperature adjustment unit, the temperature of the heat medium can be adjusted to a desired temperature. When the transfer line transfers the 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 the 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 adjusted appropriately, for example, to a temperature range in which the uncracked residue is melted.

[0045] The transfer line may be thermally insulated. By thermally 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. The raw material drying section dries and removes liquid (e.g., water, organic solvent, etc.) contained in the (meth)acrylic polymer supplied to the pyrolysis section. Hereinafter, the process of drying and removing liquid contained in the (meth)acrylic polymer is also referred to as "drying process of the (meth)acrylic polymer." In the present disclosure, the drying process of the (meth)acrylic polymer includes a process of partially removing liquid contained in the (meth)acrylic polymer and a process of completely removing 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 performed 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 a (meth)acrylic polymer, evaporation of the liquid contained in the (meth)acrylic polymer may be promoted by adjusting one or more of the environmental conditions of the (meth)acrylic polymer, such as temperature, relative humidity, airflow, and air pressure. From the viewpoint of easily controlling the amount of liquid after drying the (meth)acrylic polymer, a method of adjusting at least one of the temperature or airflow is preferred, and a method of adjusting both the temperature and airflow may also be adopted. To promote 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 efficiently drying the raw material, 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 the present disclosure, the lower part of the raw material drying section refers to a portion that comes into contact with the raw material in the direction of gravity (e.g., the bottom of a container containing the raw material, the bottom of a conveyor transporting the raw material, 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 pyrolysis section.

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

[0052] <Specific example of raw material drying> Specific examples of the transfer of the heat medium to the raw material drying section via a transfer line will be described below, but the embodiment of the present invention is 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 drawn out from the transfer line and brought into contact with the raw materials. Examples of this type include spraying the heat medium onto the raw materials. In this type, 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 types (1) or (2) may be used. (1) A type in which the heat medium is drawn out from the transfer line and brought into contact with the raw materials. (2) A type in which the transfer line is arranged in the raw material drying section. In type (1), the heat medium may be recovered or released to the atmosphere. In type (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 materials in the drying section, or a method in which the transfer line is arranged to contact the raw materials and heat the raw materials, may be used. In this case, the heat insulation on the transfer line may be appropriately adjusted, such as not being provided or being provided to the extent that efficient drying is possible.

[0054] When the heat medium is 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 this 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, such as not being provided or being provided to the extent that drying can be performed efficiently. When the heat medium is liquid and the transfer line transfers the heat medium to the lower part of the raw material drying section, the same arrangement as when the heat medium is transferred to the upper part may be used.

[0055] (Gas Treatment Unit) The regeneration device of the present disclosure may be equipped with a gas treatment unit that treats the pyrolysis gas generated in the pyrolysis unit. 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 unit that cools and liquefies the pyrolysis gas, a purification unit that increases the purity of the monomer having a (meth)acrylic group contained in the pyrolyzed gas, and a tank that stores the monomer having a (meth)acrylic group liquefied by cooling can be used in combination as needed without particular limitation. The gas treatment unit preferably includes at least one selected from the group consisting of a cooling unit that cools the pyrolysis gas and a purification unit that purifies the pyrolysis gas.

[0056] <Specific example of gas treatment section> Specific examples of the transfer of the heat transfer medium to the gas treatment section, specifically the purification section, via a transfer line will be described below. The embodiment of the present invention is not limited to the following examples, and appropriate design changes can be made to obtain similar effects.

[0057] When the heat medium is transferred to the gas treatment section, particularly the purification section, the following (1) or (2) may be used. (1) A form in which the composition to be purified in the purification section is heated. (2) A form in which the purification section is heated. Form (1) includes a method in which a part of the composition to be purified in the purification section is extracted from the purification section and introduced into the purification section from the top of the purification section, and the device or piping for circulating the composition is heated with a heat medium. Form (2) includes a method in which a transfer line is arranged along the outer peripheral wall of the purification section to heat the purification section. In either form, 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.

[0058] (Raw material supply section) The recycling apparatus 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 of supplying the raw material is not particularly limited and can be selected from known methods. The raw material supply section may include a processing device that processes the raw material, such as crushing, a detector that detects foreign matter contained in the raw material, a measuring device that controls the amount of raw material input, etc. The raw material supply section may be integrated with the raw material drying section described above, or may be an independent device from the raw material drying section. When the raw material supply section is an independent device, the raw material supply section may be provided before (upstream) the raw material drying section, or after (downstream) the raw material drying section.

[0059] (Impurity Gas Treatment Unit) The regeneration device of the present disclosure may be equipped with an impurity gas treatment unit that treats impurity gas generated in the pyrolysis unit. In the present disclosure, impurity gas refers to components other than the monomer having a (meth)acrylic group contained in the pyrolysis gas generated in the pyrolysis unit. Examples of impurity gas include chlorine gas and water vapor. The method for treating impurity gas is not particularly limited and can be selected from known methods. Known means for treating impurity gas, such as adsorbents, absorbents, metal catalysts, and filters, can be used in combination as needed without particular limitation. Specific examples of adsorbents 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, a complex of iron oxide and / or metallic iron with calcium carbonate and / or calcium oxide and carbon, and the like. Specific examples of absorbents include 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 can be sodium hydroxide, sodium carbonate, or sodium bicarbonate (NaHCO ３ The reducing agent is preferably selected from the group consisting of sodium sulfite, hydrogen peroxide, sodium thiosulfate, and sodium bisulfite (or hydrogen sulfite) (NaHSO ３ 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] (Partial Condensation Section) 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. By including a partial condensation section in the regeneration device, it is possible to selectively condense, for example, impurities contained in the pyrolysis gas discharged from the pyrolysis section that condense at a higher temperature than the monomer mainly composed of a (meth)acrylic acid ester (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 the 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 type 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] Impurities condensed from the pyrolysis gas after being cooled by the partial condensation section may be removed. The method for removing 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 section) 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 section 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] <Specific Example of Residue Storage Section> Specific examples of the transfer of the heat transfer medium to the residue storage section via 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 transferring the heat medium to the residue storage section, the following (1) or (2) may be used. (1) Heating the area from the residue discharge port of the pyrolysis section to the residue storage section. (2) Temperature adjustment of the residue storage section, such as heating or keeping warm. The methods (1) and (2) include adjusting the temperature of the undecomposed residue to a temperature equal to or higher than the melting temperature and lower than the ignition point when transferring or storing the undecomposed residue in the residue storage section, and keeping the undecomposed residue warm at this temperature. The method (1) includes arranging a transfer line along the peripheral wall of the area (e.g., piping) between the residue discharge port of the pyrolysis section and the residue storage section, and heating or keeping warm this area. The method (2) includes arranging a transfer line along the peripheral wall of the residue storage section, and heating or keeping warm the residue storage section. In either method, 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.

[0067] Second Embodiment A second embodiment of the present disclosure is a method for regenerating a (meth)acrylic polymer, the method including: a pyrolysis step of obtaining a pyrolysis gas by pyrolysis of a (meth)acrylic polymer; a heat exchange step of transferring heat from the pyrolysis gas to a heat medium; and a transport step of transporting the heat medium. The regeneration method of this embodiment may be carried out using the regeneration 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 of supplying a (meth)acrylic polymer, an impurity gas treatment step of treating 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 the details and preferred aspects 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 by thermal decomposition into a monomer having a (meth)acrylic group. The recycled monomer having a (meth)acrylic group is used, for example, as a raw material monomer for the (meth)acrylic polymer.

[0074] The (meth)acrylic group-containing monomer obtained by the recycling method of this embodiment may include methyl (meth)acrylate. The (meth)acrylic group-containing monomer obtained by the recycling method of this embodiment may also 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 method for producing a monomer having a (meth)acrylic group, the method including: 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 transport step of transporting the heat medium. The production method of this embodiment may be performed using the regeneration 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 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.

[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 supply step of supplying a (meth)acrylic polymer, an impurity gas treatment step of treating 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 the details and preferred aspects 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 a raw material. The monomer having a (meth)acrylic group obtained as a thermal decomposition product 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 also 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). 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] FIG. 1 is a diagram showing an example of the configuration of a regeneration device according to a first embodiment. The arrows in the diagram indicate the flow direction of the (meth)acrylic polymer regeneration process 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 device 100 shown in FIG. 1 further includes a transfer line A that transfers the heat medium from the heat exchange section 3 to the raw material drying section 1, and a transfer line B that transfers 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 the heat exchange section 3 to the raw material drying section 1, and transfer line B that transfers the heat medium from the raw material drying section 1 to the 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 the heat exchange section 3 to the 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.

[0088] 100 Regeneration device 1 Raw material drying section 2 Pyrolysis section 3 Heat exchange section 4 Gas treatment section 5 Undecomposed residue treatment section A, B Transfer line

Claims

1. A (meth)acrylic polymer regeneration device comprising: a pyrolysis section that thermally decomposes a (meth)acrylic polymer to obtain pyrolysis gas; a heat exchange section that transfers heat from the pyrolysis gas to a heat medium; and a transfer line that transports the heat medium.

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

4. The regeneration device 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 transfer medium to the upper or lower part of the raw material drying section.

6. The regeneration device according to claim 1, further comprising an undecomposed residue treatment section for treating 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 pyrolysis gas produced in the pyrolysis section, wherein the transfer line transfers the heat medium to the gas treatment section.

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

9. The regeneration device according to any one of claims 1 to 7, wherein the transfer line has a thermometer and a flow control valve.

10. A regeneration device according to any one of claims 1 to 7, wherein 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.

11. The regeneration device according to any one of claims 1 to 7, wherein the transfer line has a temperature adjusting section for adjusting the temperature of the heat medium.

12. The regeneration device according to any one of claims 1 to 7, wherein the transfer line is thermally insulated.

13. A regeneration device according to any one of claims 1 to 7, wherein the heat transfer medium is a gas or a liquid.

14. A method for regenerating a (meth)acrylic polymer, comprising: 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 transfer step of transferring the heat medium.

15. A method for producing a monomer having a (meth)acrylic group, comprising: 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 transfer step of transferring the heat medium.

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