How to recycle chlorine-containing resins

Abstract

To provide a method and apparatus for dechlorinating chlorine-containing resins and recovering hydrogen chloride. [Solution] The present invention relates to a method and apparatus for recovering hydrogen chloride and obtaining a solid residue usable as fuel by thermal decomposition of a chlorine-containing resin containing chlorine in the main chain or side chains. A chlorine-containing resin that has been thoroughly dried in advance is thermally decomposed under the flow of an inert gas, and the resulting oily substance and decomposition product gas are introduced into a condenser cooled to below room temperature to condense the oily substance. Furthermore, the decomposition product gas that comes out of the exhaust port is passed through water to capture the hydrogen chloride as hydrochloric acid, thereby recovering the hydrogen chloride generated by the thermal decomposition of the chlorine-containing resin as hydrochloric acid, and it has been found that a solid residue with a low chlorine content can be obtained.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for recovering hydrogen chloride and obtaining a solid residue that can be used as fuel by thermal decomposition of a chlorine-containing resin containing chlorine in the main chain or side chain.

Background Art

[0002] Conventional plastic and rubber recycling methods include thermal recycling by energy recovery during incineration, material recycling by recovering, crushing, and sorting products followed by recycling, and chemical recycling by thermally decomposing in an oxygen-free or low-oxygen environment to obtain oil products, solid residues, and decomposition-generated gases that are used as fuel or chemical raw materials. Regarding waste plastics, 8.22 million tons are generated annually in Japan (in 2020), and 86% of them are recycled by one of the above methods. Also, although currently only 4% of the recycled waste plastics are chemically recycled, it is applicable to waste plastics that contain inorganic fillers and multiple plastic materials and are difficult to recycle materially. Therefore, demand is expected to increase in the future, and in fact, studies are mainly underway on polyolefin plastics such as polyethylene, polypropylene, and polystyrene.

[0003] Polyolefin resins are relatively easy to recycle by chemical recycling, with highly carbonized residues, hydrocarbon-based oil products, and gas as the main products. In contrast, for chlorine-containing resins such as polyvinyl chloride (PVC) and polyvinylidene chloride (PVDC), hydrogen chloride (HCl) is generated by thermal decomposition as shown in Scheme 1. Therefore, when thermally decomposing chlorine-containing resins, a method is known in which an alkaline earth metal compound such as slaked lime is added and removed as an alkaline earth metal salt (for example, Patent Document 1). There is also a method of obtaining a solid residue with a low chlorine content by adding an inorganic acid such as sulfuric acid, nitric acid, or phosphoric acid or an inorganic acid salt thereof to the chlorine-containing resin and heating and melting it (for example, Patent Document 2).

Chemical Formula

[0004] However, when hydrogen chloride is removed by neutralization with a basic alkaline earth metal compound as described in Patent Document 1, it is not possible to recover the chlorine in the form of hydrogen chloride. Furthermore, there are concerns that if a large amount of chlorine-containing resin is used, excessive hydrogen chloride will be generated, or that the reaction with hydrogen chloride may be slow depending on the type of alkaline earth metal compound, resulting in insufficient removal of hydrogen chloride. In addition, if water is produced by the neutralization reaction, hydrogen chloride and water will be mixed, raising concerns that the heat treatment furnace and piping will become significantly more susceptible to corrosion. Moreover, when an inorganic acid or its inorganic salt is added to a chlorine-containing resin and heated and melted as described in Patent Document 2, the dechlorination process becomes complicated, and in addition to hydrogen chloride, acidic gases that are easily soluble in water, such as nitrogen oxides and sulfur oxides, are also generated, making it difficult to capture only hydrogen chloride with water. Furthermore, when an inorganic acid or its inorganic salt is added, there are concerns that the heat treatment furnace and piping will become significantly more susceptible to corrosion. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Patent No. 7258270 [Patent Document 2] Japanese Patent Publication No. 2002-20534 [Overview of the project] [Means for solving the problem]

[0006] Based on the above, the inventors conducted diligent studies and found that by thermally decomposing a chlorine-containing resin that has been thoroughly dried beforehand under the flow of an inert gas, the resulting oily substance and decomposition product gas are introduced into a condenser cooled to below room temperature to condense the oily substance, and the decomposition product gas that comes out of the exhaust port is passed through water to capture hydrogen chloride as hydrochloric acid, thereby recovering the hydrogen chloride generated by the thermal decomposition of the chlorine-containing resin as hydrochloric acid, and furthermore, obtaining a solid residue with a low chlorine content. In other words, the present invention provides at least, (1) A heat treatment apparatus and heat treatment method for chlorine-containing resin, characterized by comprising the steps of: (1) placing a chlorine-containing resin in a heat treatment furnace and introducing an inert gas to replace the air in the heat treatment furnace; (2) heating the heat treatment furnace while introducing the inert gas to thermally decompose the chlorine-containing resin, producing a decomposition product gas containing hydrogen chloride, an oily substance, and a solid residue; (3) cooling the oily substance and the decomposition product gas containing hydrogen chloride to near room temperature to cause the oily substance to condense, followed by passing the decomposition product gas containing hydrogen chloride through water to produce hydrochloric acid (Figure 1); (2) A heat treatment apparatus and heat treatment method for chlorine-containing resin according to (1), characterized by comprising the steps of: placing a chlorine-containing resin in a heat treatment furnace and introducing an inert gas to replace the air in the heat treatment furnace; heating the heat treatment furnace while introducing the inert gas to thermally decompose the chlorine-containing resin, thereby producing a decomposition product gas containing hydrogen chloride, an oil product, and a solid residue; and subsequently heating the solid residue in the heat treatment furnace to 600°C or higher under an inert gas atmosphere; (3) A heat treatment apparatus and heat treatment method for a chlorine-containing resin according to (1) and (2), characterized in that the chlorine-containing resin contains at least one of polyvinyl chloride, polyvinylidene chloride, and acrylonitrile-chlorinated polyethylene-styrene; (4) A method for heat treatment of a pyrolysis target according to (1), (2), and (3), characterized in that the inert gas contains at least one of nitrogen, helium, argon, xenon, neon, krypton, and carbon dioxide; Includes.

[0007] In the thermal decomposition of chlorine-containing resins such as polyvinyl chloride and polyvinylidene chloride, dechlorination produces hydrogen chloride and a solid residue whose main component is carbon. Based on this, the present invention thermally decomposes chlorine-containing resins under the flow of an inert gas, and introduces the resulting oily material and decomposition product gases into a condenser cooled to below room temperature to condense the oily material. Furthermore, the decomposition product gases that exit from the exhaust port are passed through water to capture hydrogen chloride as hydrochloric acid. As a result, the present invention has the following advantages: 1. Since the solid residue contains almost no chlorine, it can be used as a solid fuel. 2. Hydrogen chloride is captured as hydrochloric acid and is not released into the environment. Furthermore, the resulting hydrochloric acid can be used in acid treatment solutions, etc. 3. Hydrochloric acid of any desired concentration can be prepared by adjusting the amount of chlorine-containing resin added and the amount of water used to capture hydrogen chloride. 4. It can be applied even if additives such as plasticizers and antioxidants, or resins and rubbers other than chlorine-containing resins, are mixed in. 5. In composite materials of chlorine-containing resin and metal, the resin and metal can be separated. Furthermore, the metal is not oxidized due to the inert gas atmosphere.

[0008] The notable technical features of this invention are described in detail below: 1. According to the method of the present invention, when polyvinyl chloride is heated to approximately 300°C or higher in an inert gas atmosphere, both chlorine and plasticizer can be removed (Figure 3). Furthermore, if only chlorine is to be removed, it can be removed by heat treatment at approximately 250°C or higher (Figure 4). 2. As shown in Table 1, the calorific value of the solid residue produced by the method of the present invention is higher than that of wood pellets and equivalent to that of waste solid fuel (RDF (Refuse Derived Fuel)). Furthermore, when heat-treated at approximately 300°C for approximately 20 minutes, it meets the calorific value standard (approximately 25 MJ / kg) of RPF (Refuse derived paper and plastics densified fuel, which is a high-quality solid fuel mainly made from waste paper and waste plastics that are difficult to recycle from industrial waste). In addition, the chlorine content also meets the quality standard of RPF (approximately 2 wt% or less). [Table 1] 3. Hydrochloric acid can be obtained by passing the hydrogen chloride produced by the method of the present invention through a solvent. Since hydrochloric acid is classified as a hazardous substance at a concentration of approximately 10% or higher, the amount of solvent needs to be adjusted according to the amount of chlorine-containing resin, but the obtained hydrochloric acid can be used, for example, as an acid cleaning solution for metal components. The following equation holds true between the amount of chlorine-containing resin and the amount of water. • When the chlorine-containing resin is PVC

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[0009] According to the main aspect of the present invention, the following inventions are provided. [[ID=十六]] [[ID=十七]](Item 1)[[ID=十八]] [[ID=十九]]A method for recycling a chlorine-containing resin, comprising: [[ID=二十]] [[ID=二十一]]heating the chlorine-containing resin to generate a decomposition product gas containing hydrogen chloride and a solid residue mainly composed of carbon; [[ID=二十二]] [[ID=二十三]]passing the decomposition product gas containing hydrogen chloride through water to generate hydrochloric acid. [[ID=二十四]] [[ID=二十五]]A method comprising the above. [[ID=二十六]] [[ID=二十七]](Item #2)[[ID=二十八]] [[ID=二十九]]The method according to any one of the preceding items, further comprising drying the chlorine-containing resin before heating the chlorine-containing resin. [[ID=三十]] [[ID=三十一]](Item #3)[[ID=三十二]] [[ID=三十三]]The method according to any one of the preceding items, wherein the step of heating the chlorine-containing resin is carried out in an inert gas atmosphere in a heat treatment furnace. [[ID=三十四]] [[ID=三十五]](Item #4)[[ID=三十六]] [[ID=三十七]]By heating the chlorine-containing resin, an oil product is further generated, and before passing the decomposition product gas containing hydrogen chloride through water, the decomposition product gas containing the oil product and hydrogen chloride is cooled to near room temperature to agglomerate the oil product. The method according to any one of the preceding items, comprising the step of [[ID=三十八]] [[ID=三十九]](Item #5)[[ID=四十]] [[ID=四十一]]The method according to any one of the preceding items, further comprising drying the chlorine-containing resin before heating the chlorine-containing resin. [[ID=四十二]] [[ID=四十三]](Item #6)[[ID=四十四]] [[ID=四十五]]The method according to any one of the preceding items, wherein the step of heating the chlorine-containing resin is carried out at about 200°C to about 400°C. (Item 7) The method according to any one of the preceding items, wherein the step of heating the chlorine-containing resin is performed for a period of approximately 10 minutes to approximately 150 minutes. (Item 8) The method according to any one of the preceding items, wherein the chlorine-containing resin comprises vinyl chloride or vinylidene chloride as a monomer. (Item 9) The method according to any one of the preceding items, wherein the chlorine-containing resin contains at least one of polyvinyl chloride, polyvinylidene chloride, and acrylonitrile-chlorinated polyethylene-styrene. (Item 10) The method according to any one of the preceding items, wherein the chlorine-containing resin is polyvinyl chloride or polyvinylidene chloride. (Item 11) The method according to any one of the preceding items, wherein the solid residue has a calorific value of approximately 17 MJ / kg or more. (Item 12) The method according to any one of the preceding items, wherein the weight percentage of chlorine contained in the solid residue is less than approximately 2.0 wt%. (Item 13) The method according to any one of the preceding items, wherein the concentration of the hydrochloric acid is approximately 10 wt% or less. (Item 14) The method according to any one of the preceding items, wherein the chlorine-containing resin includes a plasticizer, an antioxidant, a resin or rubber different from the chlorine-containing resin, or a metal. (Item 15) The method according to any one of the preceding items, wherein the inert gas comprises at least one of nitrogen, helium, argon, xenon, neon, krypton, and carbon dioxide. [Effects of the Invention]

[0010] 1. By capturing the hydrogen chloride generated by the thermal decomposition of chlorine-containing resin as hydrochloric acid, it can be used in applications such as acid cleaning solutions. Furthermore, by controlling the amount of chlorine-containing resin and the amount of water used to recover the hydrogen chloride, hydrochloric acid of any desired concentration can be obtained. 2. The solid residue can be used as an alternative fuel to coal or charcoal. 3. Since water is not produced during the thermal decomposition of chlorine-containing resins alone, it is less likely to corrode the thermal decomposition furnace, piping, and condenser. 4. In composite materials of chlorine-containing resin and metal, these can be easily separated, and the metal is not oxidized (Figure 2). [Brief explanation of the drawing]

[0011] [Figure 1] Figure 1 shows a schematic diagram of the chlorine-containing resin dechlorination and hydrogen chloride recovery apparatus of the present invention. Description of each main part: I. Pyrolysis oven; performs pyrolysis of the chlorine-containing resin. After pyrolysis, solid residue remains here. Furthermore, when cleaning the oven after removing the solid residue, organic matter such as tar can be removed by heating while supplying air from a compressor. II. Condenser; separates the decomposition product gas (hydrogen chloride) and oily material that comes out of the pyrolysis oven. Furthermore, unwanted organic matter can be burned off by heating while supplying air from a compressor. III. Water tank; captures the generated hydrogen chloride as hydrochloric acid. Since hydrochloric acid concentrations of 10% or more are classified as hazardous substances, the amount of water in the water tank is controlled according to the amount of chlorine-containing resin subjected to pyrolysis to maintain a concentration below that level. [Figure 2] Figure 2 shows the appearance of the PVC-metal composite product (A) and the PVC-metal composite product after heat treatment at 300°C for 2 hours (B). [Figure 3] Figure 3 shows the EGA thermograms of a PVC molded product and a PVC molded product heat-treated at 200°C, 250°C, and 300°C. [Figure 4] Figure 4 shows the extracted chromatograms of VC molded products and PVC molded products heat-treated at 200°C, 250°C, and 300°C. [Figure 5] Figure 5 shows a schematic diagram of the entire heat treatment apparatus. [Figure 6] Figure 6 shows a composite material of a polyvinyl chloride molded product 39 and stainless steel 38, manufactured by roll forming. [Figure 7] Figure 7 shows a device for quantifying the chlorine content in solid residue. [Modes for carrying out the invention]

[0012] The present disclosure is described below in best form. Throughout this specification, singular expressions should be understood to include the concept of their plural form unless otherwise specified. Accordingly, singular articles (e.g., "a," "an," "the" in English) should be understood to include the concept of their plural form unless otherwise specified. Furthermore, terms used herein should be understood to have the meaning commonly used in the art unless otherwise specified. Accordingly, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this disclosure pertains. In case of any conflict, this specification (including definitions) shall prevail.

[0013] The following provides definitions of terms used specifically in this specification and / or basic technical concepts as appropriate.

[0014] (definition) In this specification, “resin” refers to an organic polymer, which may be natural or synthetic. Resins may be used interchangeably with plastics or PET (polyethylene terephthalate). Composite materials of resins with other materials are also included.

[0015] In this specification, "chlorine-containing resin" refers to a resin that contains chlorine atoms unless otherwise specified. Chlorine-containing resins include, but are not limited to, polyvinyl chloride, polyvinylidene chloride, acrylonitrile-chlorinated polyethylene-styrene, vinyl chloride-vinylidene chloride copolymer, and vinyl chloride-vinyl acetate copolymer. Copolymers of chlorine-containing resins with resins that do not contain chlorine atoms, such as acrylonitrile-chlorinated polyethylene-styrene, may also be included.

[0016] In this specification, "decomposition product gas" refers to the gas produced when a substance is decomposed, unless otherwise specified, and in this specification, in particular, to the gas produced when a resin is thermally decomposed.

[0017] In this specification, "solid residue" refers to solid material produced when a substance is decomposed, unless otherwise specified, and in this specification, in particular, to solid material produced when a resin is thermally decomposed.

[0018] In this specification, unless otherwise specified, "heat treatment furnace" refers to a heat treatment furnace for heat-treating a chlorine-containing resin, comprising a pyrolysis chamber in which the chlorine-containing resin to be heat-treated is placed, and a heating furnace capable of heating the chlorine-containing resin, wherein the pyrolysis chamber can be filled with an inert gas and is provided so that the pressure can be adjusted by a valve.

[0019] In this specification, "inert gas" means a gas that does not substantially react with substances unless otherwise specified, and includes, but is not limited to, nitrogen, helium, argon, xenon, neon, krypton, and carbon dioxide.

[0020] In this specification, "oil-based product" refers to oil produced by heating resin, unless otherwise specified.

[0021] In this specification, "recycling" means collecting materials to be recycled and converting them back into their original form or another form, unless otherwise specified. Recycling includes resource recovery. Preferably, in this specification, "resource recovery" means converting materials into materials that can be used as resources. In particular, in this specification, resource recovery means converting collected resins into fuel such as solid residues or resources such as hydrochloric acid.

[0022] In this specification, "approximately" means ±10% of the following number.

[0023] In this specification, "room temperature" refers to a temperature range of approximately 20°C to approximately 40°C.

[0024] In this specification, "or" is used when "at least one" of the items listed in the text can be adopted. The same applies to "or else". In this specification, when it is specified that "within the range" of "two values", that range includes the two values ​​themselves.

[0025] (Types of chlorine-containing resins) The chlorine-containing resin is preferably polyvinyl chloride, polyvinylidene chloride, acrylonitrile-chlorinated polyethylene-styrene, vinyl chloride-vinylidene chloride copolymer, and vinyl chloride-vinyl acetate copolymer, with polyvinyl chloride and polyvinylidene chloride being more preferred. Polyvinyl chloride and polyvinylidene chloride are preferred because the amount of hydrogen chloride generated per monomer unit is almost constant, making it easy to control the amount of chlorine-containing resin added during thermal decomposition and the amount of water used to recover hydrogen chloride. The chlorine-containing resin contains chlorine atoms, and may contain 5 to 75 wt% of chlorine atoms per total element in the resin. Preferably, may contain 50 to 75 wt% of chlorine atoms per total element in the resin.

[0026] Furthermore, two or more of the above-mentioned chlorine-containing resins may be mixed, and resins or rubbers other than chlorine-containing resins, such as polyolefin resins or natural rubber, may also be mixed. In addition, substances such as metals, organic compounds, inorganic compounds, plasticizers, antioxidants, or fillers may be included.

[0027] (Dechlorination temperature) The thermal decomposition temperature for chlorine-containing resin is preferably about 200°C to about 400°C, more preferably about 250°C to about 350°C, even more preferably about 280°C to about 320°C, and most preferably about 290°C to about 310°C. Below about 200°C, hydrogen chloride desorption from the chlorine-containing resin does not proceed sufficiently, and although hydrogen chloride is sufficiently desorbed when thermal decomposition is performed above about 400°C, the gasification of the chlorine-containing resin becomes significant, which reduces the carbon content in the solid residue and lowers the calorific value.

[0028] (Dechlorination time) The thermal decomposition time for chlorine-containing resin is preferably about 90 minutes to about 150 minutes, more preferably about 100 minutes to about 140 minutes, and most preferably about 110 minutes to about 120 minutes, when the thermal decomposition temperature is less than about 280°C. If the thermal decomposition time is less than about 90 minutes, the dehydrochlorination from the chlorine-containing resin does not proceed sufficiently, resulting in a high proportion of chlorine in the solid residue. Also, even if heat treatment is performed for a longer time than about 150 minutes, there is no significant difference in the proportion of chlorine in the solid residue, but gasification reduces the carbon content and raises concerns about a decrease in calorific value.

[0029] Furthermore, the thermal decomposition time for chlorine-containing resin is preferably about 20 minutes to about 120 minutes, more preferably about 40 minutes to about 100 minutes, and most preferably about 50 minutes to about 70 minutes, when the thermal decomposition temperature is about 280°C or higher. If the thermal decomposition time is less than about 20 minutes, the dehydrochlorination from the chlorine-containing resin does not proceed sufficiently, and the proportion of chlorine in the solid residue becomes high. Also, even if heat treatment is performed for a longer time than about 120 minutes, there is no significant difference in the proportion of chlorine in the solid residue, but there is a concern that the carbon content will decrease due to gasification and the calorific value will decrease.

[0030] (Shape of chlorine-containing resin) Chlorine-containing resin molded products can be used in any shape. Furthermore, even composite materials with metals can be used because the metal and chlorine-containing resin separate during the thermal decomposition process.

[0031] (Additives to chlorine-containing resins) Even if the chlorine-containing resin contains additives such as UV absorbers, antioxidants, plasticizers, and compatibilizers, any of these can be added as desired.

[0032] (Material of metal in chlorine-containing resin-metal composite materials) When subjecting a composite material of chlorine-containing resin and metal to thermal decomposition, the metal can preferably be any of the following: iron, aluminum, gold, silver, copper, zinc, nickel, cobalt, tin, chromium, manganese, platinum, molybdenum, niobium, bismuth, indium, or stainless steel or their alloys.

[0033] (Types of inert gases) The inert gas used in the heat treatment process of the pyrolysis target and the heat treatment process of the residue is preferably nitrogen, helium, argon, xenon, neon, krypton, or carbon dioxide, more preferably nitrogen, argon, or carbon dioxide, and most preferably nitrogen. This is because nitrogen can be supplied not only from high-pressure gas cylinders but also from nitrogen generators that separate nitrogen from the air.

[0034] (solid residue) The chlorine-containing resin produced by pyrolysis can be used as a solid fuel as a solid residue. The calorific value of the solid residue preferably meets the calorific value standards for RDF (Refuse Derived Fuel), preferably about 17 MJ / kg or more, and more preferably about 20 MJ / kg or more. Furthermore, the chlorine content of the solid residue preferably meets the quality standards for RPF (Refuse Derived Fuel), and preferably is less than about 2.0 wt%.

[0035] (Drying temperature of chlorine-containing resin) Before subjecting the chlorine-containing resin to thermal decomposition, it is necessary to dry it to remove moisture. At this time, the drying temperature of the chlorine-containing resin is preferably between approximately 50°C and approximately 150°C, more preferably between approximately 70°C and approximately 130°C, and most preferably between approximately 80°C and approximately 105°C. This is because moisture cannot be sufficiently removed below approximately 50°C, and the dehydrochlorination reaction proceeds at temperatures above approximately 150°C.

[0036] (Materials for the pyrolysis furnace) While ceramics, quartz, stainless steel, and heat-resistant steel can all be preferably used as materials for the pyrolysis furnace, ceramics and heat-resistant steel are more preferable, and heat-resistant steel is the most preferable. This is because, in the carbonization treatment of plastic waste, waste rubber waste, and woody waste, heat-resistant steel exhibits minimal strength reduction even when exposed to high temperatures for extended periods, and also has excellent impact resistance.

[0037] (Heat treatment process for materials to be pyrolyzed) Figure 5 schematically shows the entire heat treatment apparatus of the present invention. Chlorine-containing resin 3 is placed into the pyrolysis furnace 1 through the lid 2, and after closing the lid 2, valves 5 and 6 connected to the compressor 4 are all closed, and the pressure regulator 8 and valve 9 connected to the inert gas cylinder 7 are opened to introduce inert gas into the pyrolysis furnace from the piping 10 and replace it. During replacement, the inert gas flow rate can be arbitrarily adjusted with the mass flow controller 11, but it is preferable that the following equation 3 is satisfied between the inert gas flow rate at this time, the replacement time, and the pyrolysis furnace capacity.

[0038]

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[0039] Subsequently, the chlorine-containing resin 3 inside the pyrolysis furnace 1 is heated by the heater 12. The set temperature of the heater 12 can be adjusted by the temperature controller 14 via the wiring 13. During the heat treatment, the temperature inside the pyrolysis furnace 1 is measured by thermocouples 15a to 15c, and these thermocouples 15a to 15c are connected to the temperature controller 14 via the wiring 16. When the temperature inside the pyrolysis furnace 1 reaches the set temperature of the heater 12, the heat supply from the heater 11 is stopped.

[0040] Furthermore, the pressure inside the pyrolysis chamber 1 during pyrolysis can be monitored by the pressure gauge 17. If the reading on the pressure gauge 17 exceeds 0.1 MPa, G, the vent 18 may be automatically opened to control the pressure inside the pyrolysis chamber 1 and reduce it.

[0041] (Inert gas flow rate during heat treatment process) The flow rate of inert gas in the heat treatment process of chlorine-containing resin varies depending on the amount of chlorine-containing resin 3 and the capacity of the pyrolysis oven 1. However, it is sufficient that no air enters the pyrolysis oven 1 during the heat treatment process, and that the oily substances and decomposition product gases derived from the chlorine-containing resin move towards the condenser. For this reason, it is desirable that the flow rate of inert gas during the heat treatment process satisfies the following equation 4.

[0042]

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[0043] Furthermore, in Equation 4, A represents the amount of inert gas introduced into the pyrolysis furnace 1 per minute, preferably between approximately 0.1V and V, more preferably between approximately 0.2V and approximately 0.8V, and most preferably between approximately 0.3V and approximately 0.5V. If the amount of inert gas introduced into the pyrolysis furnace 1 per minute is less than approximately 0.1V, there is a concern that air will remain in the pyrolysis furnace 1 or that the oily substances and decomposition product gases will not sufficiently move towards the condenser. Also, if the amount of inert gas introduced into the pyrolysis furnace 1 per minute is greater than V, no difference is observed in preventing air from entering the pyrolysis furnace 1 or in the degree to which the oily substances and decomposition product gases move towards the condenser, so the industrial significance is diminished.

[0044] The oily substances and decomposition gases generated from the chlorine-containing resin 3 are stored in the condenser 21a via the pipe 20 from the outlet 19. Therefore, the condenser 21a stores oily substances derived from the chlorine-containing resin and additives. However, by heating with the heater 22 and distilling, relatively light oily substances that are liquid at room temperature, such as naphtha and kerosene fractions, can be separated into the condenser 21b, which is maintained at a temperature below room temperature, via the pipe 23.

[0045] Furthermore, the heater 22a is connected to the temperature controller 14 by wiring 24, and when the temperature of thermocouples 26a to 26c, which are also connected to the temperature controller 14 by wiring 25, reaches the set temperature of the heater 22, the heat supply from the heater 22a to the oil storage tank 21a can be stopped.

[0046] Hydrogen chloride and lower hydrocarbons that are gaseous at room temperature are introduced into the tank 28 through piping 27. The tank 28 is filled with solvent 29, and the hydrogen chloride is captured by the solvent 29. If water is used as the solvent 29, hydrochloric acid is produced. Inert gases and other gases that are not captured by the solvent 29 are released through piping 30.

[0047] (Material of the tank and the piping connected to the tank) The materials for the piping 27, tank 28, and piping 30 are preferably ceramic, quartz, glass, polyethylene, polypropylene, polystyrene, polycarbonate, acrylic, and polyphenylene sulfide, more preferably ceramic, polyethylene, polypropylene, polystyrene, polycarbonate, acrylic, and polyphenylene sulfide, and most preferably polyethylene and polypropylene. This is because ceramic and polyolefin resins offer high resistance to corrosion by hydrochloric acid and can be used for extended periods.

[0048] (A solvent that captures hydrogen chloride) The solvent used to capture hydrogen chloride in the water tank is preferably water, methanol, or ethanol, with water being the most preferred. The concentration of the captured hydrochloric acid is 40% or less, preferably 10% or less. Furthermore, to avoid becoming a hazardous substance, the hydrochloric acid concentration is preferably 10% or less, and it is preferable that the following formula 5 is satisfied between the weight of PVC subjected to thermal decomposition and the amount of water used to capture the generated hydrogen chloride. Hereinafter, M1 and M2 represent the molecular weights of hydrogen chloride and PVC monomer units, respectively, and W1 and W2 represent the weight of PVC subjected to thermal decomposition and the amount of water used to capture hydrogen chloride, respectively.

[0049]

number

[0050] Furthermore, when PVDC is subjected to thermal decomposition, a maximum of 2 molecules of hydrogen chloride are generated per monomer unit. Therefore, the following equation 6 must be satisfied between the weight of PVDC subjected to thermal decomposition and the amount of water used to capture the generated hydrogen chloride. Here, M3 represents the molecular weight of the PVDC monomer unit, and W3 represents the weight of PVDC subjected to thermal decomposition.

[0051]

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[0052] (Cleaning inside the pyrolysis furnace 1 after pyrolysis) After pyrolysis, valve 5 is opened, valves 6 and 9 are closed, and air is supplied from compressor 4 to the pyrolysis chamber 1 through piping 31 while heating the inside of the pyrolysis chamber 1 with heater 12 to burn and remove solid residues. At this time, the air flow rate can be controlled by mass flow controller 32. This allows tar and other substances adhering to the inner wall of the pyrolysis chamber to be removed without scrubbing with brushes, thus reducing the labor of the worker.

[0053] When heating the inside of the pyrolysis furnace 1 with the heater 12 while supplying air from the compressor 4, the heating temperature is preferably between approximately 350°C and approximately 700°C, more preferably between approximately 400°C and approximately 600°C, and most preferably between approximately 450°C and approximately 550°C. This is because if the heating temperature is below approximately 350°C, the oily material may not burn sufficiently, and even if heated at a temperature higher than approximately 700°C, there is almost no difference in the degree of combustion, making it of little industrial significance.

[0054] (Cleaning inside the condenser) The oily substances in condensers 21a and 21b can be removed by opening cocks 33a and 33b, respectively. However, it is difficult to completely remove any remaining oily substances in condensers 21a and 21b by wiping alone. Therefore, it is also possible to close valve 34 and open valve 6 to introduce air from compressor 4 through piping 30 into condensers 21a and 21b, while heating the inside of condensers 21a and 21b with heaters 22a and 22b to burn the oily substances. The airflow rate can be arbitrarily controlled by the mass flow controller 34. As a result, even if organic chlorine is generated by thermal decomposition, it is converted into hydrogen chloride, and if the oily substances contain chlorine, that chlorine is also captured by the solvent 29.

[0055] In addition, heater 22b is connected to the temperature controller 14 by wiring 35, similar to heater 22a, and when the temperature of thermocouples 37a to 37c, which are also connected to the temperature controller 14 by wiring 36, reaches the set temperature of heater 22b, the heat supply from heater 22b to condenser 21b can be stopped.

[0056] When heating the condenser 21a with heater 22a and the condenser 21b with heater 22b while supplying air from compressor 4, the heating temperature is preferably between approximately 500°C and approximately 1000°C, more preferably between approximately 600°C and approximately 900°C, and most preferably between approximately 750°C and approximately 800°C. This is because if the heating temperature is below approximately 500°C, the oil may not burn sufficiently, and even if heated at a temperature higher than approximately 1000°C, there is almost no difference in the degree of combustion of the oil, making it of little industrial significance.

[0057] (Material of the condenser) The material of the condenser 21a is preferably ceramic, quartz, stainless steel, or heat-resistant steel, more preferably ceramic, stainless steel, or heat-resistant steel, and most preferably ceramic or heat-resistant steel. This is because ceramic or heat-resistant steel offers excellent heat resistance and is resistant to corrosion. [Examples]

[0058] The applicant conducted the following experiment to investigate the effects of the present invention. The outline and results of the experiment are shown below. The present invention will be described more specifically below with reference to experimental examples, examples, and comparative examples, but the present invention is not limited to the following examples.

[0059] (Example 1) (Thermal decomposition process of chlorine-containing resin) As shown in Figure 6, approximately 1 kg of a composite material consisting of a polyvinyl chloride molded product 39 and stainless steel 38, manufactured by roll forming, was placed in a pyrolysis oven 1 with a capacity of approximately 2.5 L and subjected to pyrolysis. In this embodiment, the weight ratio of polyvinyl chloride to stainless steel in the composite material was 49:51.

[0060] With valves 9 and 34 open and valves 5 and 6 closed, nitrogen was introduced into the pyrolysis vessel 1 as an inert gas at a flow rate of approximately 1 L / min for about 5 minutes, thereby replacing the inside of the pyrolysis vessel 1 with nitrogen, which is an inert gas.

[0061] Subsequently, the inside of the pyrolysis furnace 1 was heated to 300°C by heater 12 while maintaining a nitrogen flow rate of approximately 1 L / min, and this temperature was maintained for approximately 90 minutes. The mixed gas of the decomposition product gas components of the chlorine-containing resin and nitrogen was discharged from pipe 27 and introduced into tank 28 filled with 3 L of water as the solvent 29.

[0062] After the pyrolysis treatment, the chloride ion concentration in the water in tank 28 was quantified by ion chromatography. The chloride ion concentration of distilled water was quantified using an ion chromatograph (Thermo Fisher Scientific, ICS-1600). The sample volume was 25 μl, an electrical conductivity detector was used as the detector, a Dionex IonPac AS22 (Thermo Fisher Scientific, 4 × 250 mm) was used as the separation column, and a mixed solution of 4.5 mM Na2CO3 and 1.4 mM NaHCO3 was used as the mobile phase, with a flow rate of 1.0 ml / min.

[0063] As a result, the chloride ion concentration was 2.6 mol / L and the hydrochloric acid concentration was 8.7%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride was detected.

[0064] (Quantitative determination of chlorine content in solid residue) As shown in Figure 7, 1 g of solid residue 40 was placed inside a 25 mm diameter quartz glass tube 41. Then, with the outlet open to the atmosphere, air was introduced into the quartz glass tube 41 at a flow rate of 300 ml / min from a compressor 42 (Hitachi Industrial Systems, Babycon 0.2 LE-8S) using piping 43 and a mass flow controller 44, while the tube was heated in an electric furnace 45 at 600°C for 1 hour. A stopper 46 was provided at the connection point between piping 43 and the quartz glass tube 41 to prevent air from the compressor 42 from leaking at this connection point. At this time, the gas discharged from the outlet was introduced into a Muenke bottle 48 containing 400 ml of distilled water via piping 47. Subsequently, the chloride ion concentration of the distilled water was quantified using an ion chromatograph (Thermo Fisher Scientific, ICS-1600). The sample volume was 25 μl, an electrical conductivity detector was used, a Dionex IonPac AS22 (ThermoFisher Scientific, 4 × 250 mm) separation column was used, and a mixed solution of 4.5 mM Na2CO3 and 1.4 mM NaHCO3 was used as the mobile phase, with a flow rate of 1.0 ml / min. Furthermore, the chlorine content per 1 g of solid residue 40 was calculated using the following formula 7.

[0065]

number

[0066] At this time, M Cl In this example, the weight percentage (wt%) of chlorine contained in the solid residue is C Cl C is defined as the chloride ion concentration (mg / L) in distilled water after the gas discharged from the outlet has been passed through it.Cl0 represents the chloride ion concentration (mg / L) in the distilled water before the gas discharged from the outlet is passed through, and W represents the weight (g) of the solid residue subjected to analysis.

[0067] As a result, the weight percentage of chlorine in the solid residue of this example was 0.47 wt%, which met the chlorine content standard (Grade B) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 0.6 wt%.

[0068] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was determined using an organic element analyzer (Elementar, UNICUBE). For the determination of carbon, hydrogen, nitrogen, and sulfur, 2 mg of the sample in a tin capsule was burned in contact with tungsten oxide (Elementar, S11.02-0017) while he was flowed at 200 ml / min and oxygen at a flow rate of 28 ml / min for 70 seconds. This resulted in the determination of carbon, hydrogen, and nitrogen as CO2, H2O, and NO, respectively. x and SO x It was converted to NO. x and SO x For the analysis, reduced copper (Elementar, S05 000 699) was used to convert to N2 and SO2, and N2, CO2, H2O, and SO2 were detected using a thermal conductivity detector (TCD). The sample combustion temperature and reduction temperature were set to 1150°C and 850°C, respectively. For the quantification of oxygen, 2 mg of the sample in a silver capsule was heated to 1170°C in contact with carbon black (Elementar, S03 679 910) while flowing He at 200 ml / min, and the generated CO was detected by TCD. Furthermore, the calorific value was calculated from the results of the organic elemental analysis using the following Dulong equation (Equation 8).

number

[0069] In this case, Hh represents the higher heating value (MJ / kg), and C, H, O, and S represent the weight percentages (wt%) of carbon, hydrogen, oxygen, and sulfur in the sample, respectively. The calorific value of the solid residue was considered acceptable if it was equal to or greater than the calorific value that allows it to be used as RDF (Refuse Derived Fuel) (17 MJ / kg).

[0070] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 62.1%, 6.7%, 0.5%, 0.1%, and 17.6%, respectively. Furthermore, the calorific value was 27.5 MJ / kg according to Equation 8.

[0071] (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0072] (Example 2) (Thermal decomposition process of chlorine-containing resin) The thermal decomposition of the chlorine-containing resin was carried out in the same manner as in Example 1, except that the temperature inside the thermal decomposition chamber 1 was set to 250°C using heater 12 and the thermal decomposition time was set to 120 minutes. In addition, 3 L of water was introduced into the tank 28 as the solvent 29.

[0073] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0074] As a result, the chloride ion concentration was 2.6 mol / L and the hydrochloric acid concentration was 8.5%, which falls below the 10% threshold for hydrochloric acid to be designated as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride was detected.

[0075] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0076] As a result, the weight percentage of chlorine in the solid residue of this example was 1.8 wt%, which met the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 2.0 wt%.

[0077] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0078] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 59.6%, 6.5%, 1.0%, 0.2%, and 17.3%, respectively. Furthermore, the calorific value was 26.5 MJ / kg according to Equation 8.

[0079] (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0080] (Example 3) (Thermal decomposition process of chlorine-containing resin) In this experiment, 2 kg of chlorine-containing resin, similar to that used in Example 1, was placed in the pyrolysis oven 1. The temperature inside the pyrolysis oven 1 was set to 300°C using the heater 12, and the pyrolysis time was set to 20 minutes. The pyrolysis of the chlorine-containing resin was carried out in the same manner as in Example 1. In addition, 5.2 L of water was introduced into the tank 28 as the solvent 29, and the nitrogen flow rate was maintained at 1.2 L / min during the pyrolysis.

[0081] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0082] As a result, the chloride ion concentration was 3.0 mol / L and the hydrochloric acid concentration was 9.9%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride gas was detected.

[0083] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0084] As a result, the weight percentage of chlorine in the solid residue of this example was 0.87 wt%, which met the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 2.0 wt%.

[0085] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0086] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 63.0%, 6.1%, 0.6%, 0.1%, and 17.2%, respectively. Furthermore, the calorific value was 27.1 MJ / kg according to Equation 8.

[0087] (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0088] (Example 4) (Thermal decomposition process of chlorine-containing resin) Polyvinylidene chloride molded product was used as the chlorine-containing resin. 1.2 kg of the chlorine-containing resin was placed in the pyrolysis oven 1, and the temperature inside the pyrolysis oven 1 was raised to 320°C using the heater 12. The pyrolysis time was set to 40 minutes, and the pyrolysis of the chlorine-containing resin was carried out in the same manner as in Example 1, except that argon was used as the inert gas during the pyrolysis. In addition, 10 L of water was introduced into the tank 28 as the solvent 29, and the argon flow rate was maintained at 1.1 L / min.

[0089] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0090] As a result, the chloride ion concentration was 2.5 mol / L and the hydrochloric acid concentration was 8.3%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride gas was detected.

[0091] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0092] As a result, the weight percentage of chlorine in the solid residue of this example was 0.66 wt%, which met the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastic (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastic, etc.") of less than 2.0 wt%.

[0093] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0094] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 62.1%, 4.6%, 0.5%, 0.0%, and 10.4%, respectively. Furthermore, the calorific value was 25.8 MJ / kg according to Equation 8. (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0095] (Example 5) (Thermal decomposition process of chlorine-containing resin) A polyvinyl chloride molded product was used as the chlorine-containing resin. 1.5 kg of the chlorine-containing resin was placed in the pyrolysis oven 1, and the temperature inside the pyrolysis oven 1 was set to 350°C using the heater 12. The pyrolysis time was set to 120 minutes, and the pyrolysis of the chlorine-containing resin was carried out in the same manner as in Example 1, except that argon was used as the inert gas during the pyrolysis. In addition, 8 L of water was introduced into the tank 28 as the solvent 29, and the argon flow rate was maintained at 1.0 L / min.

[0096] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0097] As a result, the chloride ion concentration was 3.0 mol / L and the hydrochloric acid concentration was 9.9%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride gas was detected.

[0098] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0099] As a result, the weight percentage of chlorine in the solid residue of this example was 0.45 wt%, which met the chlorine content standard (Grade B) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 0.6 wt%.

[0100] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0101] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 58.7%, 6.0%, 0.5%, 0.1%, and 15.1%, respectively. Furthermore, the calorific value was 25.8 MJ / kg according to Equation 8.

[0102] (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0103] (Example 6) (Thermal decomposition process of chlorine-containing resin) In this experiment, 2 kg of chlorine-containing resin, similar to that used in Example 1, was placed in the pyrolysis oven 1. The temperature inside the pyrolysis oven 1 was set to 280°C using the heater 12, and the pyrolysis time was set to 90 minutes. The pyrolysis of the chlorine-containing resin was carried out in the same manner as in Example 1. In addition, 6 L of water was introduced into the tank 28 as the solvent 29, and the nitrogen flow rate was maintained at 1.2 L / min during the pyrolysis.

[0104] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0105] As a result, the chloride ion concentration was 2.6 mol / L and the hydrochloric acid concentration was 8.7%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride was detected.

[0106] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0107] As a result, the weight percentage of chlorine in the solid residue of this example was 0.79 wt%, which met the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastic (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastic, etc.") of less than 2.0 wt%.

[0108] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0109] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 57.2%, 6.1%, 0.6%, 0.1%, and 16.6%, respectively. Furthermore, the calorific value was 25.2 MJ / kg according to Equation 8.

[0110] (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0111] (Example 7) (Thermal decomposition process of chlorine-containing resin) In this experiment, a polyvinyl chloride molded product was used as the chlorine-containing resin. 1.0 kg of the chlorine-containing resin was placed in the pyrolysis oven 1, the temperature inside the pyrolysis oven 1 was set to 250°C using the heater 12, and the pyrolysis time was set to 90 minutes. The pyrolysis of the chlorine-containing resin was carried out in the same manner as in Example 1. In addition, 7 L of water was introduced into the tank 28 as the solvent 29, and the nitrogen flow rate during pyrolysis was maintained at 1.0 L / min.

[0112] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0113] As a result, the chloride ion concentration was 2.3 mol / L and the hydrochloric acid concentration was 7.7%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride gas was detected.

[0114] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0115] As a result, the weight percentage of chlorine in the solid residue of this example was 1.95 wt%, which met the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 2.0 wt%.

[0116] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0117] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 60.9%, 6.6%, 0.5%, 0.2%, and 16.2%, respectively. Furthermore, the calorific value was 27.3 MJ / kg according to Equation 8.

[0118] (comprehensive evaluation) In this embodiment, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, and the chlorine content also met the RPF standards, so it was evaluated as suitable.

[0119] (Comparative Example 1) (Thermal decomposition process of chlorine-containing resin) The thermal decomposition of the chlorine-containing resin was carried out in the same manner as in Example 1, except that the temperature inside the thermal decomposition furnace 1 was set to 200°C using heater 12.

[0120] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0121] As a result, the chloride ion concentration was 2.1 mol / L, and the hydrochloric acid concentration was 6.7%. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14 L), but no hydrogen chloride was detected.

[0122] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0123] As a result, the weight percentage of chlorine in the solid residue of this example was 8.42 wt%, which falls below the hydrochloric acid concentration of 10%, a level that would classify it as a hazardous substance. Therefore, it did not meet the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 2 wt%.

[0124] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0125] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 54.1%, 6.5%, 1.3%, 0.1%, and 15.2%, respectively. Furthermore, the calorific value was 25.0 MJ / kg according to Equation 8.

[0126] (comprehensive evaluation) In this example, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but rather captured it as hydrochloric acid within tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF, but the chlorine content of the solid residue did not meet the RPF standard, so it was evaluated as unsuitable. This was thought to be because the desorption of hydrogen chloride did not proceed sufficiently due to the low thermal decomposition temperature.

[0127] (Comparative Example 2) (Thermal decomposition process of chlorine-containing resin) The thermal decomposition of the chlorine-containing resin was carried out in the same manner as in Example 7, except that the heat treatment time in the thermal decomposition furnace 1 was set to 60 minutes.

[0128] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0129] As a result, the chloride ion concentration was 2.3 mol / L and the hydrochloric acid concentration was 7.5%, which falls below the 10% threshold for hydrochloric acid to be designated as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride gas was detected.

[0130] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0131] As a result, the weight percentage of chlorine in the solid residue of this example was 3.56 wt%, which did not meet the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastic (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastic, etc.") of less than 2 wt%.

[0132] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0133] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 63.5%, 6.9%, 0.3%, 0.1%, and 12.4%, respectively. Furthermore, the calorific value was 29.2 MJ / kg according to Equation 8.

[0134] (comprehensive evaluation) In this example, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF. However, the chlorine content of the solid residue did not meet the RPF standards, and therefore it was deemed unsuitable. This was thought to be because the desorption of hydrogen chloride did not proceed sufficiently due to the short thermal decomposition time.

[0135] (Comparative Example 3) (Thermal decomposition process of chlorine-containing resin) The thermal decomposition of the chlorine-containing resin was carried out in the same manner as in Example 7, except that the temperature inside the thermal decomposition furnace 1 was set to 300°C and the heat treatment time was set to 10 minutes.

[0136] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0137] As a result, the chloride ion concentration was 1.1 mol / L and the hydrochloric acid concentration was 3.6%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride was detected.

[0138] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0139] As a result, the weight percentage of chlorine in the solid residue of this example was 2.41 wt%, which did not meet the chlorine content standard (Grade C) for solid fuel (RPF) made primarily from recycled paper and plastic (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastic, etc.") of less than 2 wt%.

[0140] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0141] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 62.4%, 6.4%, 0.7%, 0.0%, and 15.4%, respectively. Furthermore, the calorific value was 27.6 MJ / kg according to Equation 8.

[0142] (comprehensive evaluation) In this example, the chlorine-containing resin used underwent thermal decomposition, and the hydrogen chloride was not released into the atmosphere but was captured as hydrochloric acid within the tank 28. Furthermore, the calorific value of the solid residue was equivalent to that of RDF. However, the chlorine content of the solid residue did not meet the RPF standard, and therefore it was evaluated as unsuitable. This was thought to be because, even at a heat treatment temperature of 280°C or higher, the thermal decomposition time was too short, preventing sufficient desorption of hydrogen chloride.

[0143] (Comparative Example 4) (Thermal decomposition process of chlorine-containing resin) The thermal decomposition of the chlorine-containing resin was carried out in the same manner as in Example 1, except that the temperature inside the thermal decomposition furnace 1 was set to 500°C and the heat treatment time was 30 minutes.

[0144] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0145] As a result, the chloride ion concentration was 2.6 mol / L and the hydrochloric acid concentration was 8.7%, which falls below the 10% threshold for hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride was detected.

[0146] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0147] As a result, the weight percentage of chlorine in the solid residue of this example was 0.21 wt%, which met the chlorine content standard (Grade A) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 0.3 wt%.

[0148] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0149] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 42.6%, 3.6%, 0.3%, 0.1%, and 22.2%, respectively. Furthermore, the calorific value was 15.7 MJ / kg according to Equation 8.

[0150] (comprehensive evaluation) In this example, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid within tank 28. The chlorine content of the solid residue met the RPF standard, but the calorific value of the solid residue was lower than the RDF standard. This was thought to be because the thermal decomposition temperature was too high, causing the carbon content in the chlorine-containing resin to gasify, resulting in a lower carbon content in the solid residue.

[0151] (Comparative Example 5) (Thermal decomposition process of chlorine-containing resin) The same chlorine-containing resin as in Example 7 was used. Furthermore, the amount of chlorine-containing resin placed in the pyrolysis furnace 1 was set to 3.0 kg, and 5 L of water was introduced as the solvent 29 into the tank 28. Except for these differences, the pyrolysis of the chlorine-containing resin was carried out in the same manner as in Example 1.

[0152] After the thermal decomposition treatment, the chloride ion concentration in the water in tank 28 was determined in the same manner as in Example 1.

[0153] As a result, the chloride ion concentration was 9.6 mol / L and the hydrochloric acid concentration was 25.9%, which is higher than the 10% hydrochloric acid concentration that would classify it as a hazardous substance. Furthermore, gas components discharged from pipe 30 were collected using a gas bag, and the concentration of hydrogen chloride gas contained in the gas released into the atmosphere was measured using a gas detection tube (for hydrogen chloride, 14L), but no hydrogen chloride gas was detected.

[0154] (Quantitative determination of chlorine content in solid residue) The chlorine content in the solid residue was also quantified using the same method as in Example 1, and the chlorine content per gram of solid residue was calculated using Equation 6 above.

[0155] As a result, the weight percentage of chlorine in the solid residue of this example was 0.57 wt%, which met the chlorine content standard (Grade B) for solid fuel (RPF) made primarily from recycled paper and plastics (JIS Z7311:2010 "Solid fuel (RPF) from waste-derived paper, plastics, etc.") of less than 0.6 wt%.

[0156] (Elemental analysis of solid residue) The carbon, hydrogen, nitrogen, sulfur, and oxygen content in the solid residue was quantified using the same method as in Example 1, and the calorific value was calculated from the results of the organic elemental analysis using Equation 5.

[0157] As a result, the weight percentages of carbon, hydrogen, nitrogen, sulfur, and oxygen in the solid residue obtained in this example were 42.6%, 3.6%, 0.3%, 0.1%, and 22.2%, respectively. Furthermore, the calorific value was 15.7 MJ / kg according to Equation 8.

[0158] (comprehensive evaluation) In this example, the thermal decomposition of the chlorine-containing resin did not release hydrogen chloride into the atmosphere, but instead captured it as hydrochloric acid in tank 28. The chlorine content of the solid residue met the RPF standard, and the calorific value of the solid residue was equivalent to that of RDF. However, the hydrochloric acid concentration in tank 28 after thermal decomposition was higher than the designated concentration for hazardous substances, so it was evaluated as unsuitable. This was thought to be because the amount of water in tank 28 was insufficient relative to the amount of chlorine-containing resin subjected to thermal decomposition.

[0159] (summary) Table 2 summarizes the thermal decomposition process and hydrogen chloride capture process of the chlorine-containing resin for Examples 1-7 and Comparative Examples 1-5. Table 3 summarizes the hydrogen chloride concentration of solvent 29 after thermal decomposition, the hydrogen chloride concentration of the outlet gas, the chlorine content of the solid residue, the elemental composition, and the calorific value for Examples 1-7 and Comparative Examples 1-5.

[0160] [Table 2]

[0161] [Table 3] [Explanation of symbols]

[0162] 1 Pyrolysis oven 2 Lid 3 Chlorine-containing resin 4 Compressor 5 Valve 6 Valve 7 Inert gas cylinder 8 Pressure regulator 9 Valve 10 Mass flow controller 11 Piping 12 Heater 13 Wiring 14 Temperature controller 15a~15c Thermocouple 16 Wiring 17 Gauge pressure gauge 18 Vent 19 Outlet 20 Piping 21a~21b Condenser 22a~22b Heater 23 Piping 24 Wiring 25 Wiring 26a~26c Thermocouple 27 Piping 28 Tank 29 Solvent 30 Piping 31 Piping 32 Mass flow controller 33a~33b Cock 34 Valve 35 Wiring 36 Wiring 37a~37c Thermocouple 40 Solid residue 41 42 Quartz glass tube 43 Compressor 44 Piping 45 Mass flow controller 46 Electric furnace 47 Stopper 48 Piping 49 Muenke bottle

Claims

1. A method for recycling chlorine-containing resins, A step of heating the chlorine-containing resin to produce a decomposition product gas containing hydrogen chloride and a solid residue whose main component is carbon, The process involves passing the decomposition product gas containing hydrogen chloride through water to produce hydrochloric acid. Methods that include...

2. The method according to claim 1, further comprising the step of drying the chlorine-containing resin before heating the chlorine-containing resin.

3. The method according to claim 1, wherein the step of heating the chlorine-containing resin is performed in a heat treatment furnace under an inert gas atmosphere.

4. The method according to claim 3, further comprising the step of heating the chlorine-containing resin to generate an oily substance, and before passing the decomposition product gas containing hydrogen chloride through water, cooling the oily substance and the decomposition product gas containing hydrogen chloride to near room temperature to cause the oily substance to condense.

5. The method according to claim 4, further comprising the step of drying the chlorine-containing resin before heating the chlorine-containing resin.

6. The method according to any one of claims 1 to 5, wherein the step of heating the chlorine-containing resin is performed at a temperature of approximately 200°C to approximately 400°C.

7. The method according to claim 6, wherein the step of heating the chlorine-containing resin is performed for a period of about 10 minutes to about 150 minutes.

8. The method according to any one of claims 1 to 5, wherein the chlorine-containing resin contains vinyl chloride or vinylidene chloride as a monomer.

9. The method according to claim 8, wherein the chlorine-containing resin contains at least one of polyvinyl chloride, polyvinylidene chloride, and acrylonitrile-chlorinated polyethylene-styrene.

10. The method according to claim 9, wherein the chlorine-containing resin is polyvinyl chloride or polyvinylidene chloride.

11. The method according to any one of claims 1 to 5, wherein the solid residue has a calorific value of approximately 17 MJ / kg or more.

12. The method according to any one of claims 1 to 5, wherein the weight percentage of chlorine contained in the solid residue is less than about 2.0 wt%.

13. The method according to any one of claims 1 to 5, wherein the concentration of the hydrochloric acid is about 10 wt% or less.

14. The method according to any one of claims 1 to 5, wherein the chlorine-containing resin comprises a plasticizer, an antioxidant, a resin or rubber different from the chlorine-containing resin, or a metal.

15. The method according to any one of claims 3 to 5, wherein the inert gas comprises at least one of nitrogen, helium, argon, xenon, neon, krypton, and carbon dioxide.

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