Integrated waste plastic pyrolysis system capable of treating pyrolysis gas at different temperature ranges

Abstract

To provide an integrated thermal decomposition system for waste plastics capable of thermal decomposition gas treatment by temperature range.SOLUTION: An integrated thermal decomposition system for waste plastics capable of thermal decomposition gas treatment by temperature range comprises a step of performing thermal decomposition of waste plastics and simultaneously removing wax components and chlorine (Cl)-containing gas components from the thermal decomposition gases according to the thermal decomposition temperature range.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an integrated pyrolysis system for waste plastics capable of treating pyrolysis gases at different temperature ranges, and more particularly to an integrated pyrolysis system for waste plastics capable of treating pyrolysis gases at different temperature ranges, including a process of pyrolyzing waste plastics and simultaneously removing wax components and chlorine (Cl)-containing gas components contained in the pyrolysis gases at different temperature ranges. [Background technology]

[0002] There are many different types of plastics, including polyethylene (PE), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polystyrene (PS), polyurethane (PU), etc. Demand for these plastics has exploded because their physical properties can be tailored to suit various applications, they are easy to process, and they can be produced from crude oil, an inexpensive raw material. However, issues such as greenhouse gas emissions and environmental pollution that arise from the process of producing plastics using crude oil, the primary raw material, have emerged, and research and development is underway to find ways to recycle used and waste plastics.

[0003] Methods for recycling the waste plastics are generally classified into physical recycling, thermal recycling, and chemical recycling.

[0004] Physical recycling is a method of reproducing plastics using pellets or flakes obtained by melting and extruding used plastics after pre-processing (collection, washing, sorting, and crushing). This method has the advantage of generating relatively little carbon during recycling, but has problems such as the need for low levels of contamination in applicable plastics, and the complicated and costly pre-processing steps such as washing and separation.

[0005] The thermal recycling is a method of burning waste plastics or mixtures in an oxygen atmosphere using an incinerator to produce heat sources such as steam and hot water.

[0006] Chemical recycling is a method of recycling waste plastics by chemically changing them into other substances, and has the advantage of being able to produce raw materials that are the same as those obtained from crude oil by breaking down polymers.

[0007] In particular, chemical recycling using pyrolysis allows fuel or chemical raw materials to be recovered from waste plastics by heat treatment in an oxygen-free or low-oxygen atmosphere.Compared to incineration methods, this method does not produce hazardous substances such as dioxins or nitrogen oxides (NOx), and can be carried out efficiently with relatively simple separation and cleaning.

[0008] However, when thermally decomposing PVC (polyvinyl chloride), which contains chlorine (Cl), among waste plastic raw materials, there is a problem that highly corrosive hydrogen chloride gas (HCl) is generated, which causes corrosion and breakdown of equipment.

[0009] In addition, during the thermal decomposition of waste plastics, components that are solid at room temperature, typically wax, may be produced, which may solidify on the outer wall of the heat exchanger installed in the thermal decomposition reactor, reducing heat transfer efficiency or causing clogging inside the heat exchanger.

[0010] Prior art documents include Korean Patent Publication No. 10-1179153 (published on September 7, 2012) which discloses only a dechlorination method and apparatus for directly reacting hydrogen chloride gas generated during the thermal decomposition of raw materials, including PVC, with an alkaline molten salt to capture and remove the salt, and Korean Patent Publication No. 10-2539139 (published on June 1, 2023) which discloses only a catalytic reactor for wax decomposition which modifies the wax in thermal cracking oil using a wax adsorption catalyst packed inside the reactor.

[0011] However, while hydrogen chloride gas can be decomposed at relatively low temperatures, wax decomposition occurs at higher temperatures. Therefore, it is difficult to set the optimal temperature when performing these two decomposition processes in a single reactor. Furthermore, since the properties of the gases generated vary depending on the temperature at which waste plastic is decomposed, a new waste plastic pyrolysis system that captures and processes these gases separately is needed. [Prior art documents] [Patent documents]

[0012] [Patent Document 1] Korean Patent Publication No. 10-1179153 (Published on September 7, 2012) [Patent Document 2] Korean Patent Publication No. 10-2539139 (Published June 1, 2023) Summary of the Invention [Problem to be solved by the invention]

[0013] The present invention has been made to solve the above-mentioned problems, and aims to provide an integrated waste plastic pyrolysis system that can efficiently and economically perform pyrolysis treatment of waste plastic and can process pyrolysis gases in different temperature ranges.

[0014] Another object of the present invention is to provide an integrated waste plastic pyrolysis system capable of treating pyrolysis gases by temperature zone, in which the pyrolysis of waste plastic is divided into temperature zones and the products generated by each temperature zone are collected and treated separately. [Means for solving the problem]

[0015] According to one embodiment of the present invention, the waste plastic pyrolysis system capable of treating pyrolysis gases in different temperature ranges includes a waste plastic input unit that supplies waste plastics to a pyrolysis reaction unit using a transfer screw rotatably installed by a driving means; a pyrolysis reaction unit that pyrolyzes the waste plastics supplied from the waste plastic input unit; a catalytic decomposition reaction unit including a wax catalytic decomposition reaction unit that receives a pyrolysis reaction product containing a wax component from the pyrolysis reaction unit and decomposes the wax component through a catalytic reaction; and a dechlorination catalytic reaction unit that receives a pyrolysis reaction product containing a chlorine component from the pyrolysis reaction unit and decomposes the chlorine component through a catalytic reaction; a pyrolysis oil recovery unit that receives a pyrolysis reaction product from the pyrolysis reaction unit and the catalytic decomposition reaction unit, condenses the pyrolysis reaction product, and obtains pyrolysis oil; and a storage unit that stores uncondensed gas discharged from the pyrolysis oil recovery unit. and an uncondensed gas circulation unit that receives the uncondensed gas from the uncondensed gas storage unit, catalytically decomposes the high molecular weight hydrocarbons in the uncondensed gas, and then supplies the carbon-containing uncondensed gas to the thermal decomposition reaction unit. The thermal decomposition reaction unit thermally decomposes the waste plastic supplied from the waste plastic input unit, and its internal space is divided into two or more stages depending on the temperature range applied during the thermal decomposition. The thermal decomposition reaction products from each stage of the thermal decomposition reaction unit are collected and discharged separately so that they can be processed independently. Depending on the state of the thermal decomposition reaction products from each stage, they are either immediately transferred to the subsequent (downstream) thermal decomposition oil recovery unit, directly transferred to a wax catalytic decomposition reaction unit within the catalytic decomposition reaction unit, or directly transferred to a dechlorination catalytic reaction unit within the catalytic decomposition reaction unit.

[0016] In one embodiment, the thermal decomposition reaction section includes a primary thermal decomposition reaction section that receives waste plastic from a waste plastic input device and performs primary thermal decomposition within a predetermined temperature range, a secondary thermal decomposition reaction section that receives non-pyrolyzed reactants from the primary thermal decomposition reaction section and performs secondary thermal decomposition within a higher temperature range than the primary thermal decomposition reaction section, and a tertiary thermal decomposition reaction section that receives non-pyrolyzed reactants from the secondary thermal decomposition reaction section and performs tertiary thermal decomposition within a higher temperature range than the secondary thermal decomposition reaction section.

[0017] In one embodiment, the waste plastic input section includes a raw material storage section in which waste plastic raw material is stored, a raw material supply conveyor that transfers the waste plastic raw material from the raw material storage section to the continuous input section, a hopper that receives the waste plastic raw material from the raw material supply conveyor, a sealed section that receives the waste plastic raw material from the hopper and blocks the inflow of oxygen from the outside, and a raw material continuous input section that receives the waste plastic raw material from the sealed section, preheats and presses it, and transfers it to the pyrolysis reaction section using a transfer screw.

[0018] In one embodiment, the pyrolysis reaction section includes an internal heater for at least partially supporting the pyrolysis reactants and supplying heat to each of a plurality of stages in the pyrolysis reaction section.

[0019] In one embodiment, the thermal decomposition reaction section is characterized in that it includes an uncondensed gas supply nozzle section in each of a plurality of stages within the thermal decomposition reaction section, the uncondensed gas being recycled and supplied from the uncondensed gas circulation section and being supplied into the thermal decomposition reaction section.

[0020] In one embodiment, the temperature range during the thermal decomposition reaction in the first thermal decomposition reaction section is 200°C or less, the temperature range during the thermal decomposition reaction in the second thermal decomposition reaction section is 200°C to 350°C, and the temperature range during the thermal decomposition reaction in the third thermal decomposition reaction section is 350°C to 500°C.

[0021] In one embodiment, the catalytic decomposition reaction unit includes an outer cylinder and an inner cylinder located within the outer cylinder. A wax catalytic decomposition reaction unit for catalytic decomposition of wax components is formed in the space between the outer cylinder and the inner cylinder. A dechlorination catalytic reaction unit for catalytic decomposition of chlorine components is formed in the inner space of the inner cylinder. The outer cylinder is connected to a first inlet through which a tertiary pyrolysis reaction product from the tertiary pyrolysis reaction unit flows into the wax catalytic decomposition reaction unit. A wax catalytic decomposition gas product transfer pipe connects the outer cylinder and the inner cylinder. The wax catalytic decomposition gas product is transferred to the dechlorination catalytic reaction unit in the inner cylinder after catalytic reaction of the tertiary pyrolysis reaction product in the wax catalytic decomposition reaction unit.

[0022] In one embodiment, the tertiary pyrolysis reaction product of the waste plastics flowing into the outer cylinder undergoes a wax catalytic decomposition reaction and is then transferred to the dechlorination catalytic reaction unit of the inner cylinder through a wax catalytic decomposition gas product transfer pipe. The inner cylinder is provided with a second inlet for allowing the secondary pyrolysis reaction product from the secondary pyrolysis reaction unit to flow into the dechlorination catalytic reaction unit, and a gas outlet for discharging to the outside the reaction product generated after the secondary pyrolysis reaction product and / or the wax catalytic decomposition gas product undergo a catalytic reaction in the dechlorination catalytic reaction unit.

[0023] In one embodiment, the temperature range of the catalytic reactions in the wax catalytic decomposition reaction section and the dechlorination catalytic reaction section is in the range of 300°C to 500°C.

[0024] In one embodiment, the outer cylinder may further include a wax decomposition catalyst inlet and a wax decomposition catalyst outlet, and the inner cylinder may further include a dechlorination catalyst inlet and a dechlorination catalyst outlet.

[0025] In one embodiment, the pyrolysis oil recovery unit includes a primary pyrolysis oil recovery unit that receives a pyrolysis reaction resultant from the pyrolysis reaction unit and the catalytic decomposition reaction unit, and primarily condenses the pyrolysis reaction resultant to obtain pyrolysis oil; and a secondary pyrolysis oil recovery unit that receives uncondensed gas from the primary pyrolysis oil recovery unit, and secondarily condenses the uncondensed gas to obtain pyrolysis oil.

[0026] In one embodiment, the combustion device further includes an uncondensed gas combustion and discharge section that receives uncondensed gas from the uncondensed gas circulation section, combusts the gas, and discharges the gas into the atmosphere.

[0027] In one embodiment, the uncondensed gas combustion and discharge section includes a hot air stove that receives a supply of uncondensed gas from the uncondensed gas circulation section, a burner that burns the uncondensed gas in the hot air stove, and a gas cooler that cools the combustion gas discharged from the hot air stove and discharges it into the atmosphere. [Effects of the Invention]

[0028] The present invention is an integrated process in which waste plastic pyrolysis system performs pyrolysis of waste plastic in a pyrolyzer and then condenses the pyrolysis reaction product in an oil recovery device including a condenser to obtain pyrolysis oil. The entire process is configured compactly, allowing for economical and efficient pyrolysis of waste plastic.

[0029] In addition, chlorine (Cl) and wax components generated during thermal decomposition and contained in the thermal decomposition product are removed through catalytic decomposition in one catalytic decomposition reactor, and the thermal decomposition product from which the chlorine and wax components have been removed is supplied to an oil recovery device, thereby preventing corrosion of the equipment and preventing problems such as reduced heat exchange efficiency and pipe blockage caused by solidification of wax inside the oil recovery device and piping.

[0030] In addition, the present invention has the advantage that, when removing chlorine and wax components contained in the pyrolysis reaction product, the chlorine and wax components are simultaneously removed using one catalytic decomposition reactor, thereby reducing equipment costs compared to conventional plastic pyrolysis systems that require separate equipment for removing chlorine and wax components.

[0031] In addition, the present invention has the advantage that the thermal decomposition of waste plastics can be performed at different temperatures and the resulting pyrolysis gases can be collected and treated separately, thereby reducing the overall energy consumption of the pyrolysis process and enabling highly efficient pyrolysis. [Brief explanation of the drawings]

[0032] [Figure 1] 1 is an exemplary diagram illustrating an integrated pyrolysis system for waste plastics capable of treating pyrolysis gas in different temperature ranges according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Generally, the nomenclature used herein is well known and commonly used in the art.

[0034] Throughout this specification, when a part "comprises" a certain element, this means that it can further include other elements, rather than excluding other elements, unless otherwise specified.

[0035] The present invention relates to an integrated pyrolysis system for waste plastics that can treat pyrolysis gases in different temperature ranges, and includes a process of removing chlorine (Cl)-containing gas components and wax components contained in the resultant pyrolysis reaction product of waste plastics using a single catalytic decomposition reactor.

[0036] Hereinafter, the integrated waste plastic pyrolysis system capable of treating pyrolysis gas in different temperature ranges according to the present invention will be described in detail with reference to the accompanying drawings.

[0037] FIG. 1 is an exemplary diagram illustrating an integrated waste plastic pyrolysis system capable of treating pyrolysis gas in different temperature ranges according to an embodiment of the present invention.

[0038] As shown in FIG. 1, the integrated waste plastic pyrolysis system (10) capable of treating pyrolysis gases at different temperature ranges according to the present invention includes a waste plastic input unit (100) for supplying waste plastic raw materials to a pyrolysis reactor, a pyrolysis reactor (200) for pyrolyzing the waste plastic, a catalytic decomposition reactor (300) for catalytically decomposing and removing chlorine (Cl)-containing gas components and wax components in the pyrolysis reaction product discharged from the pyrolysis reactor (200), a pyrolysis oil recovery unit (400) for condensing the pyrolysis reaction product and recovering pyrolysis oil, an uncondensed gas storage unit (500) for storing the uncondensed gas discharged from the pyrolysis oil recovery unit (400), and an uncondensed gas circulation unit (600) for receiving the uncondensed gas from the uncondensed gas storage unit (500) and recirculating it to the pyrolysis reactor (200).

[0039] More specifically, the waste plastic input section (100) supplies waste plastic to the pyrolysis reaction section using a transfer screw (141; an extruder screw fitted in a horizontally extending barrel) that is rotatably mounted by a drive means, and includes a raw material storage section (110) in which waste plastic raw material is stored, a raw material supply conveyor (120) that transfers the waste plastic raw material from the raw material storage section (110) to the continuous input section (140), a hopper (121) that receives the waste plastic raw material from the raw material supply conveyor, a sealed section (130) that receives the waste plastic raw material from the hopper (121) and blocks the inflow of oxygen from the outside, and a continuous raw material input section (140) that receives the waste plastic raw material from the sealed section (130), preheats and presses it, and transfers it to the pyrolysis reaction section using the transfer screw (141).

[0040] The continuous raw material input section (140) may be provided with a heating means so that the waste plastics can be melted while moving through the transfer screw (141) and fed to the thermal decomposition reaction section (200).

[0041] In this case, the waste plastics supplied to the continuous raw material input section (140) can be crushed into flakes or granules in a separate device or process (not shown), or can be pre-treated to make them easier to pyrolyze.

[0042] The continuous raw material input section (140) can be purged with an inert gas such as nitrogen to prevent the waste plastic from coming into contact with oxygen and maintain an oxygen-free atmosphere, and the inlet passage between the continuous raw material input section (140) and the pyrolysis reaction section (200) is sealed from the outside so that oxygen does not flow in together with the waste plastic.

[0043] In addition, the continuous raw material input section (140) includes a section for preheating the waste plastic raw material to about 120°C and melting the waste plastic raw material so that the thermal decomposition can be carried out smoothly in the thermal decomposition reaction section (200). The preheated and melted waste plastic raw material is compressed in a sealed structure and then input into the thermal decomposition reaction section (200).

[0044] The thermal decomposition reaction section (200) thermally decomposes the waste plastic supplied from the waste plastic input section (100), and the internal space is divided into two or more stages (particularly, each area divided in the height direction; 210, 220, 230) according to the temperature range applied during thermal decomposition.

[0045] As an example, the pyrolysis reaction section (200) includes a primary pyrolysis reaction section (210) that receives waste plastic from the waste plastic input section (100) and performs primary pyrolysis within a predetermined temperature range, a secondary pyrolysis reaction section (220) that receives non-pyrolyzed reactants from the primary pyrolysis reaction section (210) and performs secondary pyrolysis within a higher temperature range than the primary pyrolysis reaction section, and a tertiary pyrolysis reaction section (230) that receives non-pyrolyzed reactants from the secondary pyrolysis reaction section (220) and performs tertiary pyrolysis within a higher temperature range than the secondary pyrolysis reaction section (220).

[0046] In this way, the pyrolysis space is separated by the upper and middle internal heaters (240) that divide the inside of the pyrolysis reaction section (200) into upper, middle and lower sections in the illustrated example. This results in excellent heat transfer efficiency due to the upper and lower internal heaters, and heat exchange occurs between the upper and lower sections, reducing overall heat energy loss within the pyrolysis reaction section (200) and enabling efficient use of heat energy.

[0047] In addition, each of the stages in the pyrolysis reaction unit (200) is provided with a separate pyrolysis reaction product outlet through which the pyrolysis reaction product is discharged, so that the gas generated in each pyrolysis reaction unit (200) can be treated in a different manner.

[0048] That is, the pyrolysis reaction products of the pyrolysis reaction unit (200) are collected and discharged individually so that they can be treated independently. Depending on the state of each pyrolysis reaction product, they are either immediately transferred to the pyrolysis oil recovery unit in the subsequent stage, or directly transferred to the wax catalytic decomposition reaction unit (311) in the catalytic decomposition reaction unit (300), or directly transferred to the dechlorination catalytic reaction unit (321) in the catalytic decomposition reaction unit (300).

[0049] The pyrolysis reaction section (200) also includes an internal insertion type heater (240), which in the illustrated example is a horizontally extending planar heater, for supporting the pyrolysis reactants and supplying heat to each of the multiple stages in the pyrolysis reaction section (200).

[0050] The interior of the pyrolysis reaction unit 200 is divided into multiple pyrolysis reaction spaces by the internal heater 240. The internal heater 240 may be a partition plate extending horizontally or at an angle thereto.

[0051] As explained above as an example, when the pyrolysis reaction unit (200) is divided into the first to third pyrolysis reaction units, a total of three internal insertion heaters are provided, and the interior of the pyrolysis reaction unit (200) is divided into the first to third pyrolysis reaction units by the internal insertion heaters. That is, two internal insertion heaters (upper and middle) are provided vertically in two rows at a predetermined interval in the space within the pyrolysis reaction unit (200), and one internal insertion heater (lower) is provided on the bottom surface of the pyrolysis reaction unit (200).

[0052] In addition, the thermal decomposition reaction section (200) is provided with an uncondensed gas supply nozzle section (630) including a number of nozzles for supplying the uncondensed gas recycled from the uncondensed gas circulation section (600) into each reaction section in each of the plurality of stages (210, 220, 230) in the thermal decomposition reaction section (200).

[0053] As the uncondensed gas is supplied to each pyrolysis reaction section (210, 220, 230) through the uncondensed gas supply nozzle section (630), it serves to mix the pyrolysis raw material and the pyrolysis reactant, thereby improving the pyrolysis efficiency.

[0054] Here, the temperature range during the pyrolysis reaction in the primary pyrolysis reaction section (210) is 200°C or less, the temperature range during the pyrolysis reaction in the secondary pyrolysis reaction section (220) is 200°C to 350°C, and the temperature range during the pyrolysis reaction in the tertiary pyrolysis reaction section (230) is 350°C to 500°C. The primary pyrolysis reaction section (210) mainly produces hard pyrolysis gas, the secondary pyrolysis reaction section (220) produces pyrolysis gas containing chlorine (Cl) components such as hydrogen chloride, and the tertiary pyrolysis reaction section (230) produces pyrolysis gas containing wax.

[0055] The pyrolysis reaction unit (200) may use a method for transferring waste plastic raw materials from the first pyrolysis reaction unit (210) to the second pyrolysis reaction unit (220), and then from the second pyrolysis reaction unit (220) to the third pyrolysis reaction unit (230). For example, the transfer may be performed using a screw (especially a sealed screw conveyor similar to the sealed unit (130)).

[0056] The waste plastics supplied to the thermal decomposition reaction section 200 may also contain a catalyst that can enhance the thermal decomposition efficiency by contacting the waste plastics with an inert gas and / or recycled uncondensed gas to be directly heated and thermally decomposed. The catalyst may be selected from known thermal decomposition catalysts such as metal catalysts, metal oxide catalysts, and zeolite molecular sieve catalysts, but is not limited thereto.

[0057] Meanwhile, the solid residue remaining after pyrolysis in the pyrolysis reaction section (200) may weaken heat transfer, impede the pyrolysis reaction rate, and inhibit the production of pyrolysis oil, so after a certain residence time, it can be discharged to the outside of the pyrolysis reaction section (200) through a residue discharge section. The residue discharge section may be a residue discharge section of a known pyrolysis device, and for example, a transfer screw or a hopper with a scraper may be used.

[0058] The pyrolysis reaction product produced in the first pyrolysis reaction unit (210) of the pyrolysis reaction unit (200) is a hard pyrolysis gas that does not contain wax components, etc., and is therefore not supplied to the next catalytic decomposition reactor but is directly supplied to the pyrolysis oil recovery unit (400). The pyrolysis reaction products produced in the second pyrolysis reaction unit (220) and the third pyrolysis reaction unit (230) are supplied to the catalytic decomposition reaction unit (300).

[0059] The catalytic decomposition reaction unit (300) receives mainly chlorine-containing and wax-containing pyrolysis reaction products from the second and third pyrolysis reaction units (210, 220) and decomposes and removes wax and chlorine from the pyrolysis reaction products through catalytic reactions. The catalytic decomposition reaction unit (300) includes an outer cylinder (310) and an inner cylinder (320) located within the outer cylinder (310). A wax catalytic decomposition reaction unit (311) for catalytic decomposition of wax components is formed in the space between the outer cylinder (310) and the inner cylinder (320), and a dechlorination catalytic reaction unit (321) for catalytic decomposition of chlorine components is formed within the inner cylinder (320). The reactor of the catalytic decomposition reaction unit (300) may be configured as a fixed bed or a fluidized bed, preferably a fluidized bed.

[0060] In addition, the outer cylinder (310) is connected to a first inlet (312) through which the tertiary pyrolysis reaction product from the tertiary pyrolysis reaction part (230) flows into the wax catalytic decomposition reaction part (311).

[0061] In addition, the catalytic decomposition reaction unit (300) is provided with a wax catalytic decomposition gas product transfer pipe (323) connecting the outer cylinder (310) and the inner cylinder (320) to transfer the wax catalytic decomposition gas product generated after the tertiary pyrolysis reaction product is catalytically reacted in the wax catalytic decomposition reaction unit (311) to the dechlorination catalytic reaction unit (321) of the inner cylinder (320).

[0062] The inner cylinder (320) is also provided with a second inlet (322) through which the secondary pyrolysis reaction product generated in the secondary pyrolysis reaction section (220) flows into the dechlorination catalytic reaction section (321), and a gas outlet (324) through which the wax catalytic decomposition gas product, which is transferred from the secondary pyrolysis reaction section (220) and / or the tertiary pyrolysis reaction product generated in the tertiary pyrolysis reaction section (230) to the dechlorination catalytic reaction section (321) through the wax catalytic decomposition gas product transfer pipe (323) after passing through the wax catalytic decomposition reaction section (311), reacts with the dechlorination catalyst, and the resulting reaction product is discharged to the outside.

[0063] In addition, the inner cylinder (320) can receive reaction heat from the wax catalytic decomposition reaction section (311) between the inner cylinder (320) and the outer cylinder (310) surrounding it, thereby improving the thermal efficiency of the catalytic decomposition reaction section (300).

[0064] The wax catalytic decomposition reaction section (311) is not limited to any particular reaction conditions as long as they are capable of decomposing the wax components produced by the thermal decomposition reaction of waste plastics. Preferably, the wax catalytic decomposition reaction can be carried out in the range of 300°C to 500°C.

[0065] The wax decomposition catalyst is not particularly limited as long as it is a catalyst that can decompose wax components generated from the thermal decomposition reaction of waste plastics. For example, the catalyst may be a zeolite carrier carrying one or more metals selected from Fe, Zn, Pt, and Pd.

[0066] A wax decomposition catalyst inlet (315) may be further formed in the middle of the outer cylinder (310) (above the jacket formed by the outer cylinder (310) and the inner cylinder (320)), and the wax decomposition catalyst before reaction may be introduced into the wax catalytic decomposition reaction unit (311) through the wax decomposition catalyst inlet (315). The number of wax decomposition catalyst inlets (315) is not limited to one, but an even number of inlets (315) may be provided symmetrically to prevent the catalyst from being introduced unevenly. For example, two wax decomposition catalyst inlets (315) may be provided symmetrically with respect to the center line of the wax catalytic decomposition reaction unit (311).

[0067] In addition, the dechlorination catalytic reaction section (321) is not limited as long as it can remove hydrogen chloride gas generated from the thermal decomposition reaction of waste plastics, but preferably, the dechlorination catalytic decomposition reaction can be carried out at a temperature in the range of 300°C to 500°C.

[0068] The dechlorination catalyst is not limited as long as it is a catalyst that can remove hydrogen chloride gas generated from the thermal decomposition reaction of waste plastics. For example, the dechlorination catalyst may be a catalyst in which one or more metals selected from Co and Zn are supported on one or more supports selected from zeolite, alumina, and silica.

[0069] A dechlorination catalyst inlet (327) may be further formed in the upper portion of the outer cylinder (310) (a region above the jacket portion formed by the outer cylinder (310) and the inner cylinder (320)), and the dechlorination catalyst before reaction may be introduced into the dechlorination catalytic reaction section (321) through the dechlorination catalyst inlet (327). The number of the dechlorination catalyst inlets (327) is not limited to one, and an even number of inlets (327) may be provided symmetrically to prevent the catalyst from being introduced unevenly. For example, two dechlorination catalyst inlets (327) may be provided symmetrically to each other with respect to the center line of the dechlorination catalytic reaction section (321).

[0070] A wax decomposition catalyst outlet 313 may be further formed at the lower end of the outer cylinder 310, and a dechlorination catalyst outlet 325 may be further formed at the inner cylinder. After the reaction, the wax decomposition catalyst and the dechlorination catalyst may be discharged to the outside and removed through the wax decomposition catalyst outlet 313 and the dechlorination catalyst outlet 325, respectively, and may be collected and stored in a wax decomposition catalyst recovery storage tank 314 and a dechlorination catalyst recovery storage tank 326, respectively.

[0071] The shapes of the outer cylinder (310) and the inner cylinder (320) in the catalytic decomposition reaction section (300) are not particularly limited. For example, the lower surface may have a bulging shape such as a conical shape (a cone shape or a tapered shape) that bulges downward.

[0072] With the above structure, the catalytic decomposition reaction unit (300) is equipped with both the wax catalytic decomposition reaction unit (311) and the dechlorination catalytic reaction unit (321) in a single reactor, and can simultaneously remove chlorine-containing gas components such as hydrogen chloride generated from the thermal decomposition of chlorine (Cl)-containing plastics such as PVC as raw materials, along with wax components generated from the thermal decomposition of waste plastics.

[0073] The pyrolysis oil recovery unit (400) receives the pyrolysis reaction product from the pyrolysis reaction unit (200) and the catalytic decomposition reaction unit (300) and condenses it to obtain pyrolysis oil. More specifically, the pyrolysis oil recovery unit (400) receives the primary pyrolysis reaction product from the primary pyrolysis reaction unit (210) in the pyrolysis reaction unit (200) and the pyrolysis reaction product from which chlorine and wax components have been decomposed / removed from the catalytic decomposition reaction unit (300), and condenses it using a heat exchanger (condenser) to obtain pyrolysis oil.

[0074] In addition, the pyrolysis oil recovery unit (400) may be provided with two types of pyrolysis oil recovery units (400) to improve the oil recovery rate from the pyrolysis reaction product. That is, the primary pyrolysis oil recovery unit (410) receives the pyrolysis reaction product from the pyrolysis reaction unit (200) and the catalytic decomposition reaction unit (300) and primarily condenses the pyrolysis reaction product to obtain pyrolysis oil, while the secondary pyrolysis oil recovery unit (420) receives the uncondensed gas from the primary pyrolysis oil recovery unit (410) and secondary condenses it to obtain pyrolysis oil.

[0075] The primary and secondary oil collecting units (410, 420) may be any known oil condensing device without limitation, and may be provided with a scraper capable of removing viscous oil accumulated on the surface of the condenser.

[0076] The uncondensed gas storage section (500) stores the uncondensed gas discharged from the pyrolysis oil recovery section.

[0077] The uncondensed gas circulation unit (600) receives uncondensed gas from the uncondensed gas storage unit (500), catalytically decomposes harmful gases in the uncondensed gas, and then supplies the uncondensed gas from which the harmful gases have been removed to the thermal decomposition reaction unit (200). For this purpose, the uncondensed gas circulation unit (600) may include a circulation blower (610) and a catalytic tower (620) for catalytically decomposing hydrocarbons in the uncondensed gas.

[0078] The catalyst tower (620) catalytically decomposes harmful gases such as VOC, HCl, SOx, and NOx that may be contained in the uncondensed gas, thereby purifying the uncondensed gas.

[0079] In addition, the integrated waste plastic pyrolysis system (10) according to the present invention can catalytically decompose harmful gases in the uncondensed gas through the uncondensed gas circulation unit (600) and then recirculate the uncondensed gas to the pyrolysis reaction unit (200), thereby improving the pyrolysis efficiency in the pyrolysis reaction unit (200). The uncondensed gas supplied to the pyrolysis reaction unit (200) contains hydrocarbon components such as hydrogen and methane, especially hydrogen, and when it is brought into direct contact with the molten waste plastic, it can function as both a heat transfer medium and a decomposition catalyst, thereby increasing the pyrolysis efficiency of the waste plastic and reducing the amount of expensive inert gas or catalyst used.

[0080] In addition, as described above, the uncondensed gas supplied to the pyrolysis reaction section (200) through the uncondensed gas circulation section (600) is supplied to each of the pyrolysis reaction sections (210, 220, 230) through the uncondensed gas supply nozzle section (630), thereby serving to mix the pyrolysis raw material and the pyrolysis reactant, thereby further improving the pyrolysis efficiency.

[0081] In addition, the integrated waste plastic pyrolysis system (10) according to the present invention includes an uncondensed gas combustion and discharge section (700) that receives uncondensed gas from the uncondensed gas circulation section (600) and discharges it into the atmosphere (ATM) where it is combusted.

[0082] In this case, the uncondensed gas combustion and discharge unit (700) may include a hot air furnace (710) that receives uncondensed gas from the uncondensed gas circulation unit (600), a burner (720) that burns the uncondensed gas in the hot air furnace (710), and a gas cooler (730) that cools the combustion gas discharged from the hot air furnace (710) and discharges it into the atmosphere (ATM).

[0083] Although the present invention has been described above with reference to the embodiments described in the specification or illustrated in the accompanying drawings, these are merely illustrative, and those skilled in the art will recognize that various modifications and equivalent embodiments are possible. Therefore, the technical scope of the present invention should be determined by the following claims. [Explanation of symbols]

[0084] 10. Integrated waste plastic pyrolysis system capable of treating pyrolysis gases at different temperatures 100 Waste plastic input section 110 Raw material storage section 120 Raw material supply conveyor 130 Sealed part 140 Continuous raw material input section 200 Pyrolysis reaction section 210 Primary pyrolysis reaction section 220 Secondary pyrolysis reaction section 230 Tertiary pyrolysis reaction section 300 Catalytic decomposition reaction section 310 Outer cylinder 311 Wax catalytic decomposition reaction section 312 1st inlet 313 Wax decomposition catalyst outlet 314 Wax cracking catalyst recovery storage tank 320 Inner cylinder 321 Dechlorination catalytic reaction section 322 2nd inlet 323 Wax catalytic cracking gas product transfer pipe 324 Gas outlet 325 Dechlorination catalyst outlet 326 Dechlorination catalyst recovery storage tank 400 Pyrolysis Oil Recovery Section 410 Primary pyrolysis oil recovery section 420 Secondary pyrolysis oil recovery section 500 Uncondensed gas storage section 600 Uncondensed gas circulation section 610 Circulating blower 620 Catalyst Tower 700 Uncondensed gas combustion exhaust 710 Hot stove 720 Burner 730 Gas Cooler

Claims

1. a waste plastic input section that supplies waste plastic to the pyrolysis reaction section using a transfer screw that is rotatable by a driving means; a thermal decomposition reaction section for thermally decomposing the waste plastic supplied from the waste plastic input section; a catalytic decomposition reaction unit including a wax catalytic decomposition reaction unit that receives a wax component-containing pyrolysis reaction product from the pyrolysis reaction unit and decomposes the wax component through a catalytic reaction, and a dechlorination catalytic reaction unit that receives a chlorine component-containing pyrolysis reaction product from the pyrolysis reaction unit and decomposes the chlorine component through a catalytic reaction; a pyrolysis oil recovery unit that receives the pyrolysis reaction products from the pyrolysis reaction unit and the catalytic decomposition reaction unit, and condenses the products to obtain pyrolysis oil; an uncondensed gas storage section for storing the uncondensed gas discharged from the pyrolysis oil recovery section; an uncondensed gas circulation section that receives uncondensed gas from the uncondensed gas storage section, catalytically decomposes high molecular weight hydrocarbons in the uncondensed gas, and then supplies the carbon component-containing uncondensed gas to the thermal decomposition reaction section, The thermal decomposition reaction section thermally decomposes the waste plastic supplied from the waste plastic input section, and the internal space is divided into two or more stages according to the temperature range applied during thermal decomposition, The pyrolysis reaction products in each stage of the pyrolysis reaction unit are collected and discharged separately so that they can be treated independently. Depending on the state of the pyrolysis reaction product in each stage, the pyrolysis reaction product is either immediately transferred to the pyrolysis oil recovery unit in the subsequent stage, or directly transferred to the wax catalytic decomposition unit in the catalytic decomposition reaction unit, or directly transferred to the dechlorination catalytic reaction unit in the catalytic decomposition reaction unit. This waste plastic pyrolysis system is capable of treating pyrolysis gases by temperature range.

2. The thermal decomposition reaction section is a primary pyrolysis reaction section that receives waste plastic from the waste plastic input device and performs primary pyrolysis within a predetermined temperature range; a secondary pyrolysis reaction section that receives a reactant that has not been pyrolyzed from the primary pyrolysis reaction section and performs secondary pyrolysis in a temperature range higher than that of the primary pyrolysis reaction section; and a tertiary pyrolysis reactor that receives reactants that have not been pyrolyzed from the secondary pyrolysis reactor and performs tertiary pyrolysis at a temperature range higher than that of the secondary pyrolysis reactor.

3. The waste plastic input unit is a raw material storage section in which waste plastic raw materials are stored; a raw material supply conveyor that transfers the waste plastic raw material from the raw material storage section to a continuous input section; a hopper that receives the waste plastic raw material from the raw material supply conveyor; a sealing section that receives the waste plastic raw material from the hopper and blocks the inflow of oxygen from the outside; and a continuous raw material input unit that receives waste plastic raw material from the sealed unit, preheats and presses the raw material, and transfers it to the pyrolysis reaction unit using a transfer screw.

4. The thermal decomposition reaction section is 2. The waste plastic pyrolysis system according to claim 1, wherein each of the plurality of stages in the pyrolysis reaction section comprises an internal heater for supporting the pyrolysis reactants and supplying heat.

5. The thermal decomposition reaction section is 2. The waste plastic pyrolysis system capable of treating pyrolysis gas by temperature zone as set forth in claim 1, wherein each of the plurality of stages in the pyrolysis reaction section includes an uncondensed gas supply nozzle section including a plurality of nozzles through which the uncondensed gas recycled from the uncondensed gas circulation section is supplied into the pyrolysis reaction section.

6. 3. The waste plastic pyrolysis system capable of treating pyrolysis gases by temperature range as set forth in claim 2, wherein the temperature range during the pyrolysis reaction in the first pyrolysis reaction unit is 200°C or less, the temperature range during the pyrolysis reaction in the second pyrolysis reaction unit is 200°C to 350°C, and the temperature range during the pyrolysis reaction in the third pyrolysis reaction unit is 350°C to 500°C.

7. The catalytic decomposition reaction section is an outer cylinder and an inner cylinder located in an internal space of the outer cylinder, a wax catalytic decomposition reaction section for catalytic decomposition of a wax component is formed in a space between the outer cylinder and the inner cylinder; A dechlorination catalytic reaction section for catalytic decomposition of chlorine components is formed in the internal space of the inner cylinder, The outer cylinder is connected to a first inlet through which a tertiary pyrolysis reaction product from the tertiary pyrolysis reactor is introduced into the wax catalytic decomposition reactor.

3. The waste plastic pyrolysis system capable of treating pyrolysis gases according to temperature ranges as set forth in claim 2, wherein a wax catalytic decomposition gas product transfer pipe is formed to connect the outer cylinder and the inner cylinder, through which a wax catalytic decomposition gas product generated after a catalytic reaction of a resultant of the tertiary pyrolysis reaction in the wax catalytic decomposition reaction unit is transferred to the dechlorination catalytic reaction unit in the inner cylinder.

8. The tertiary pyrolysis reaction product of the waste plastics flowing into the outer cylinder is transferred to the dechlorination catalytic reaction part of the inner cylinder through a wax catalytic decomposition gas product transfer pipe after the wax catalytic decomposition reaction. The inner cylinder has: a second inlet through which a secondary pyrolysis reaction resultant flows from the secondary pyrolysis reaction unit to the dechlorination catalytic reaction unit; 8. The waste plastic pyrolysis system capable of treating pyrolysis gases by temperature range as set forth in claim 7, further comprising a gas outlet through which reaction products generated after the secondary pyrolysis reaction result and / or wax catalytic decomposition gas product undergo catalytic reaction in the dechlorination catalytic reaction unit are discharged to the outside.

9. 2. The waste plastic pyrolysis system capable of treating pyrolysis gases in different temperature ranges according to claim 1, wherein the temperature ranges of the catalytic reactions in the wax catalytic decomposition reaction unit and the dechlorination catalytic reaction unit are in the range of 300°C to 500°C.

10. 8. The waste plastic pyrolysis system capable of treating pyrolysis gases by temperature range according to claim 7, wherein the outer cylinder further comprises a wax decomposition catalyst inlet and a wax decomposition catalyst outlet, and the inner cylinder further comprises a dechlorination catalyst inlet and a dechlorination catalyst outlet.

11. The pyrolysis oil recovery unit includes: a primary pyrolysis oil recovery unit that receives the pyrolysis reaction product from the pyrolysis reaction unit and the catalytic decomposition reaction unit, and primarily condenses the pyrolysis reaction product to obtain pyrolysis oil; and a secondary pyrolysis oil recovery unit that receives uncondensed gas from the primary pyrolysis oil recovery unit and secondarily condenses the uncondensed gas to obtain pyrolysis oil.

12. 2. The waste plastic pyrolysis system capable of treating pyrolysis gas by temperature range as described in claim 1, further comprising an uncondensed gas combustion and discharge unit that receives uncondensed gas from the uncondensed gas circulation unit, combusts the uncondensed gas, and discharges it into the atmosphere.

13. The uncondensed gas combustion and exhaust section includes: a hot stove that receives uncondensed gas from the uncondensed gas circulation section; a burner for burning uncondensed gas in the hot stove; 13. The waste plastic pyrolysis system capable of treating pyrolysis gases according to claim 12, further comprising: a gas cooler that cools the combustion gas discharged from the hot stove and discharges the cooled combustion gas into the atmosphere.

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