Mixture for waste plastic decomposition treatment, and method for producing mixture for waste plastic decomposition treatment

Abstract

To provide a waste plastic decomposition treatment mixture capable of improving decomposability of waste plastics when decomposing the waste plastic decomposition treatment mixture in a decomposition treatment apparatus.SOLUTION: A waste plastic decomposition treatment mixture for decomposing waste plastic with a decomposition treatment apparatus comprises: molten waste plastic that is a molten material of the waste plastic; and a raw oil. A residual ratio (a filter product / the waste plastic contained in the waste plastic decomposition treatment mixture) of the filter product (that is the waste plastic decomposition treatment mixture having passed through a 40-mesh filter, and satisfies equations 1 to 3 to the waste plastic contained in the waste plastic decomposition treatment mixture) is 0.35 or less by mass. The equation 1 indicates 0.850 g / cm3≤Density (15°C)≤1.150 g / cm3, the equation 2 indicates 1.400≤Refractive index (70°C)≤1.650, and the equation 3 indicates 4.0 mm2 / s≤kinematic viscosity (200°C)≤20.0 mm2 / s.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a mixture for waste plastic decomposition treatment and a method for producing the mixture for waste plastic decomposition treatment.

Background Art

[0002] The low effective utilization rate of waste plastics and environmental pollution caused by marine waste plastics and the like have become global issues. As one of the methods for recycling waste plastics, chemical recycling can be mentioned. Regarding the technology of chemical recycling, various studies have been made conventionally.

[0003] For example, Patent Document 1 includes melting a plastic material (1) to form a plastic melt, degassing, and then sending it to a depolymerization reactor (3), and adding a fraction obtained from crude oil as a solvent (6) to the plastic melt to lower the viscosity of the plastic melt solution supplied to the depolymerization reactor (3) below the viscosity of the plastic melt. A method is disclosed.

[0004] Patent Document 2 discloses a method for decomposing a hydrocarbon polymer in a fluid catalytic cracking (FCC) unit, in which a mixture of the hydrocarbon polymer and a hydrocarbon oil selected from FCC gasoline, light cracked gas oil, heavy cracked gas oil, cracked residue oil, atmospheric residue oil, and desulfurized residue oil is mixed with the FCC feedstock oil and supplied to the FCC unit.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] Patent Document 1 describes that by adding a solvent to a plastic melt, the viscosity of the plastic melt solution can be reduced. However, since the plastic melt solution obtained by the method of Patent Document 1 simply adds a solvent, the miscibility is insufficient. As a result, when decomposing in a depolymerization reactor, the degradability of the plastic material may not be sufficiently improved. Patent Document 2 describes a method for decomposing a mixture of a hydrocarbon polymer and a hydrocarbon oil using an FCC unit that can decompose high-boiling fractions in crude oil into high-value gasoline and the like by a catalytic reaction. However, since Patent Document 2 does not pay any attention to the solubility of the hydrocarbon polymer in the hydrocarbon oil, the mixture of the hydrocarbon polymer and the hydrocarbon oil obtained by the method of Patent Document 2 is likely to have insufficient miscibility. As a result, when decomposing in an FCC unit, the degradability of the hydrocarbon polymer may not be sufficiently improved.

[0007] An object of the present invention is to provide a mixture for decomposing waste plastics that can improve the degradability of waste plastics when decomposed in a decomposition treatment apparatus, and a method for producing the mixture for decomposing waste plastics.

Means for Solving the Problems

[0008] According to one aspect of the present invention, there is provided a mixture for decomposing waste plastics for decomposing waste plastics in a decomposition treatment apparatus, wherein the mixture for decomposing waste plastics contains a molten waste plastic that is a melt of the waste plastic and a raw material oil, and satisfies the following mathematical formulas (Formula 1), (Formula 2), and (Formula 3), When the waste plastic decomposition treatment mixture is passed through a 40-mesh filter, a waste plastic decomposition treatment mixture is provided in which the residual ratio of the filtrate to the waste plastic contained in the waste plastic decomposition treatment mixture (the filtrate / the waste plastic contained in the waste plastic decomposition treatment mixture) is 0.35 or less by mass ratio. 0.850 g / cm 3 ≦ Density (15 °C) ≦ 1.150 g / cm 3 … (Equation 1) 1.400 ≦ Refractive index (70 °C) ≦ 1.650 … (Equation 2) 4.0 mm 2 / s ≦ Kinematic viscosity (200 °C) ≦ 20.0 mm 2 / s … (Equation 3)

[0009] In the waste plastic decomposition treatment mixture according to one aspect of the present invention, the feedstock oil is preferably at least one selected from the group consisting of heavy cracked light oil, cracked residue oil, atmospheric residue oil, desulfurized residue oil, desulfurized vacuum light oil, non-desulfurized vacuum light oil, non-desulfurized vacuum residue oil, mineral oil, heavy light oil, desulfurized heavy light oil, desulfurized vacuum residue oil, and decanted oil.

[0010] In the waste plastic decomposition treatment mixture according to one aspect of the present invention, the waste plastic preferably contains at least one of waste plastic derived from polyethylene and waste plastic derived from polypropylene.

[0011] According to one aspect of the present invention, there is provided a method for producing a waste plastic decomposition treatment mixture for decomposing waste plastic in a decomposition treatment apparatus, a first preparation step of preparing a molten waste plastic mixed oil by mixing a molten waste plastic, which is a melt of the waste plastic, and a first feedstock oil; a second preparation step of preparing a waste plastic decomposition treatment mixture by mixing the molten waste plastic mixed oil prepared in the first preparation step and a second feedstock oil, wherein the first feedstock oil and the second feedstock oil each satisfy the following mathematical formulas (Equation 4), (Equation 5), (Equation 6), and (Equation 7), When the waste plastic decomposition treatment mixture prepared in the second preparation step is passed through a 40-mesh filter, the residual ratio of the filtrate to the waste plastic contained in the waste plastic decomposition treatment mixture (the filtrate / the waste plastic contained in the waste plastic decomposition treatment mixture) is 0.35 or less by mass ratio, The first feedstock oil and the second feedstock oil are the same as or different from each other. A method for producing a waste plastic decomposition treatment mixture is provided. 0.850 g / cm 3 ≦ Density (15 °C) ≦ 1.150 g / cm 3 … (Equation 4) 1.400 ≦ Refractive index (70 °C) ≦ 1.650 … (Equation 5) 3.0 mm 2 / s ≦ Kinematic viscosity (75 °C) ≦ 55.0 mm 2 / s … (Equation 6) 240 g / mol ≦ Molecular weight ≦ 1000 g / mol … (Equation 7)

[0012] In the method for producing a waste plastic decomposition treatment mixture according to one aspect of the present invention, it is preferable that the first feedstock oil and the second feedstock oil each have a hydrogen bonding term (δh) represented by the Hansen solubility parameter of 1.5 or less and a dipole-dipole force term (δp) of 4.0 or less.

[0013] In the method for producing a waste plastic decomposition treatment mixture according to one aspect of the present invention, it is preferable that the first feedstock oil and the second feedstock oil are each at least one selected from the group consisting of heavy cracked light oil, cracked residue oil, atmospheric residue oil, desulfurized residue oil, desulfurized vacuum light oil, non-desulfurized vacuum light oil, non-desulfurized vacuum residue oil, mineral oil, heavy light oil, desulfurized heavy light oil, desulfurized vacuum residue oil, and decanted oil.

[0014] In the method for producing a waste plastic decomposition treatment mixture according to one aspect of the present invention, it is preferable that the waste plastic contains at least one of waste plastic derived from polyethylene and waste plastic derived from polypropylene.

Advantages of the Invention

[0015] According to one aspect of the present invention, when decomposing with a decomposition processing apparatus, it is possible to provide a mixture for waste plastic decomposition processing that can improve the decomposability of waste plastics, and a method for manufacturing the mixture for waste plastic decomposition processing.

Brief Description of the Drawings

[0016]

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Best Mode for Carrying Out the Invention

[0017] In this specification, a numerical range represented by "~" means a range including the numerical value described before "~" as the lower limit value and the numerical value described after "~" as the upper limit value.

[0018] 〔First Embodiment〕 The mixture for waste plastic decomposition treatment of this embodiment (hereinafter, also referred to as the decomposition treatment mixture) is a mixture for waste plastic decomposition treatment for decomposing waste plastic in a decomposition treatment apparatus. The mixture for waste plastic decomposition treatment includes molten waste plastic, which is a melt of waste plastic, and a raw material oil, satisfies the following mathematical formulas (Formula 1), (Formula 2), and (Formula 3), and when the mixture for waste plastic decomposition treatment is passed through a 40-mesh filter, the residual ratio of the filtrate to the waste plastic contained in the mixture for waste plastic decomposition treatment (the filtrate / the waste plastic contained in the mixture for waste plastic decomposition treatment) is 0.35 or less by mass ratio. 0.850 g / cm 3 ≦ Density (15 °C) ≦ 1.150 g / cm 3 … (Formula 1) 1.400 ≦ Refractive index (70 °C) ≦ 1.650 … (Formula 2) 4.0 mm 2 / s ≦ Kinematic viscosity (200 °C) ≦ 20.0 mm 2 / s … (Formula 3)

[0019] The filtrate refers to the substance (unit: kg) that could not pass through a 40-mesh filter among the waste plastic (waste plastic dissolved in the raw material oil) contained in the decomposition treatment mixture. For example, when 49 kg of raw material oil and 1.0 kg of molten waste plastic are mixed to prepare 50 kg of the decomposition treatment mixture, and when this 50 kg of the decomposition treatment mixture is passed through a 40-mesh filter, if the substance (filtrate) that could not pass through the filter is 0.35 kg, The residual ratio of the filtered material (the filtered material / the waste plastic contained in the decomposition treatment mixture) is calculated as 0.35 (0.35 / 1.0) by mass ratio.

[0020] The decomposition treatment mixture of this embodiment satisfies the mathematical formulas (Formula 1) to (Formula 3), and the residual ratio of the filtered material (the filtered material / the waste plastic contained in the decomposition treatment mixture) is 0.35 or less by mass ratio. The fact that the residual ratio of the filtered material is 0.35 or less by mass ratio indicates that the molten waste plastic and the raw material oil are mixed in a state that is nearly uniform in the decomposition treatment mixture. Therefore, according to the decomposition treatment mixture of this embodiment, the decomposability of the waste plastic can be improved when decomposing with a decomposition treatment apparatus. The decomposition treatment mixture of this embodiment can be obtained, for example, by the method for producing a decomposition treatment mixture of the second embodiment described later.

[0021] In the decomposition treatment mixture of this embodiment, the preferred ranges of the mathematical formulas (Formula 1), (Formula 2), and (Formula 3) are as follows.

[0022] <Density (15 °C)> In the decomposition treatment mixture of this embodiment, the density (15 °C) preferably satisfies the following mathematical formula (Formula 1A). The density (15 °C) indicates the density at 15 °C. 0.900 g / cm 3 ≦ Density (15 °C) ≦ 1.050 g / cm 3 …(Formula 1A) The density (15 °C) of the decomposition treatment mixture can be measured in accordance with "Crude oil and petroleum products - Method for determining density - Part 1: Vibration method" of JIS K 2249-1 (2011) or "Crude oil and petroleum products - Method for determining density - Part 2: Hydrometer method" of JIS K 2249-2 (2011).

[0023] <Refractive index (70 °C)> In the decomposition treatment mixture of this embodiment, the refractive index (70 °C) preferably satisfies the following mathematical formula (Formula 2A). The refractive index (70 °C) indicates the refractive index at 70 °C. 1.480 ≤ refractive index (70 °C) ≤ 1.620... (Formula 2A) The refractive index (70 °C) of the decomposition treatment mixture can be measured using the product of Atago Co., Ltd. (product number: RX-7000α).

[0024] <Kinematic viscosity (200 °C)> In the decomposition treatment mixture of this embodiment, the kinematic viscosity (200 °C) preferably satisfies the following mathematical formula (Formula 3A). The kinematic viscosity (200 °C) indicates the kinematic viscosity at 200 °C. 4.0 mm 2 / s ≤ kinematic viscosity (200 °C) ≤ 12.0 mm 2 / s... (Formula 3A) The kinematic viscosity (200 °C) of the decomposition treatment mixture is a value estimated according to the method for estimating the kinematic viscosity at an arbitrary temperature of JIS K 2207, by measuring the kinematic viscosities at 150 °C and 180 °C in accordance with the high-temperature kinematic viscosity test method for "Petroleum Asphalt" of JIS K 2207 (1996).

[0025] <Residual ratio of the filtrate> When the decomposition treatment mixture of this embodiment is passed through a 40-mesh filter, the residual ratio of the filtrate to the waste plastic contained in the decomposition treatment mixture (the filtrate / the waste plastic contained in the decomposition treatment mixture) is 0.35 or less by mass ratio. The lower the residual ratio of the filtrate (the filtrate / the waste plastic contained in the decomposition treatment mixture), the more preferable.

[0026] <Feedstock oil> The feedstock oil contained in the mixture for decomposition treatment is not particularly limited, but is preferably at least one selected from the group consisting of heavy cracked gas oil (HCO), cracked residue oil (CLO), atmospheric residue oil (RC, HPRC), desulfurized residue oil (DSRC), desulfurized vacuum gas oil (VHHGO), non-desulfurized vacuum gas oil (VGO), non-desulfurized vacuum residue oil (VC), mineral oil (e.g., HG-500 (mineral oil of 500 neutral fraction), etc.), heavy gas oil (HGO), desulfurized heavy gas oil (DS-HGO), desulfurized vacuum residue oil (DS-VC), and deasphalted oil (DAO).

[0027] <Waste plastic> Examples of waste plastics include non-chlorinated plastics, chlorinated plastics, and mixtures thereof. The shape of the waste plastic is not particularly limited, and it is preferably appropriately selected according to the specifications of the melting apparatus. Examples of non-chlorinated plastics include polyethylene, polypropylene, propylene-ethylene copolymer, polystyrene, polybutene, ethylene oligomer, butene oligomer, styrene oligomer, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon, epoxy resin, and phenol resin. Examples of polyethylene include high-density polyethylene, low-density polyethylene, and linear low-density polyethylene. Examples of chlorinated plastics include polyvinyl chloride and polyvinylidene chloride. The waste plastic preferably contains at least any one of waste plastics derived from vinyl polymers (e.g., polyethylene, polypropylene, propylene-ethylene copolymer, polystyrene, polybutene, ethylene oligomer, butene oligomer, and styrene oligomer). More preferably, the waste plastic contains at least any one of waste plastics derived from polyethylene and waste plastics derived from polypropylene. The waste plastic preferably does not substantially contain waste plastic derived from polystyrene and waste plastic derived from ethylene vinyl acetate. "Not substantially contain" means that the content of waste plastic derived from polystyrene and waste plastic derived from ethylene vinyl acetate is 10% by mass or less, preferably 5% by mass or less, based on the total amount of the waste plastic.

[0028] 〔Second Embodiment〕 A method for producing a mixture for decomposing waste plastic in the second embodiment (hereinafter, also referred to as the production method of the second embodiment) is a method for producing a mixture for decomposing waste plastic for decomposing waste plastic in a decomposition treatment apparatus, and includes a first preparation step of preparing a molten waste plastic mixed oil by mixing a molten waste plastic, which is a melt of waste plastic, with a first raw material oil, and a second preparation step of preparing a mixture for decomposing waste plastic by mixing the molten waste plastic mixed oil prepared in the first preparation step with a second raw material oil. The first raw material oil and the second raw material oil each satisfy the following mathematical formulas (Formula 4), (Formula 5), (Formula 6), and (Formula 7). When the mixture for decomposing waste plastic prepared in the second preparation step is passed through a 40-mesh filter, the residual ratio of the filtrate to the waste plastic contained in the mixture for decomposing waste plastic (the filtrate / the waste plastic contained in the mixture for decomposing waste plastic) is 0.35 or less by mass ratio. The first raw material oil and the second raw material oil are the same as or different from each other. 0.850 g / cm 3 ≦ Density (15°C) ≦ 1.150 g / cm 3 …(Formula 4) 1.400 ≦ Refractive index (70°C) ≦ 1.650 …(Formula 5) 3.0 mm 2 / s ≦ Kinematic viscosity (75°C) ≦ 55.0 mm 2 / s …(Formula 6) 240 g / mol ≦ Molecular weight ≦ 1000 g / mol …(Formula 7)

[0029] The inventors of the present invention mixed molten waste plastic with a first raw material oil having specific properties (first preparation step), and further mixed the molten waste plastic mixed oil prepared in the first preparation step with a second raw material oil having specific properties (second preparation step). As a result, when the decomposition treatment mixture obtained in the second preparation step was passed through a 40-mesh filter, it was found that the residual ratio of the filtrate to the waste plastic contained in the decomposition treatment mixture (the filtrate / the waste plastic contained in the decomposition treatment mixture) could be 0.35 or less by mass ratio. The fact that the residual ratio of the filtrate is 0.35 or less by mass ratio indicates that the molten waste plastic and the raw material oil are mixed in a state close to being uniform in the decomposition treatment mixture. Therefore, according to the production method of the second embodiment, when decomposing with a decomposition treatment apparatus, a decomposition treatment mixture capable of improving the decomposability of waste plastic can be obtained. For example, the decomposition treatment mixture of the first embodiment can be obtained by the production method of the second embodiment.

[0030] In the production method of the second embodiment, the preferred ranges of Formula (Formula 4), Formula (Formula 5), Formula (Formula 6), and Formula (Formula 7) are as follows.

[0031] <Density (15 °C)> In the first raw material oil and the second raw material oil, the density (15 °C) preferably satisfies the following formula (Formula 4A) respectively. 0.900 g / cm 3 ≦ Density (15 °C) ≦ 1.050 g / cm 3 …(Formula 4A) The density (15 °C) of the first raw material oil and the second raw material oil can be measured in the same manner as the density (15 °C) of the decomposition treatment mixture described in the first embodiment.

[0032] <Refractive index (70 °C)> In the first raw material oil and the second raw material oil, the refractive index (70 °C) preferably satisfies the following formula (Formula 5A). 1.480 ≦ Refractive index (70 °C) ≦ 1.620…(Formula 5A) The refractive indices (at 70°C) of the first feedstock oil and the second feedstock oil can be measured in the same manner as the refractive index (at 70°C) of the decomposition treatment mixture described in the first embodiment.

[0033] <Kinematic viscosity (at 75°C)> In the first feedstock oil and the second feedstock oil, it is preferable that the kinematic viscosity (at 75°C) satisfies the following mathematical formula (Formula 6A). 3.0 mm 2 / s ≤ kinematic viscosity (at 75°C) ≤ 45.0 mm 2 / s … (Formula 6A) The kinematic viscosities (at 75°C) of the first feedstock oil and the second feedstock oil are values measured in accordance with JIS K 2283 (2000), "Crude oil and petroleum products - Test method for kinematic viscosity and method for calculating viscosity index".

[0034] <Molecular weight> In the first feedstock oil and the second feedstock oil, it is preferable that the molecular weight satisfies the following mathematical formula (Formula 7A). 240 g / mol ≤ molecular weight ≤ 500 g / mol … (Formula 7A) The molecular weights of the first feedstock oil and the second feedstock oil can be calculated in accordance with UOP Method 375-07 (Calculation of UOP Characterization Factor and Estimation of Molecular Weight of Pertroleum Oils).

[0035] <Residual ratio of filter residue> In the production method of the second embodiment, when the decomposition treatment mixture prepared in the second preparation step is passed through a 40-mesh filter, the residual ratio of the filter residue to the waste plastic contained in the decomposition treatment mixture (the filter residue / the waste plastic contained in the decomposition treatment mixture) (mass ratio) is preferably as low as possible, similar to the first embodiment.

[0036] <First feedstock oil and second feedstock oil> As the first feedstock oil and the second feedstock oil used in the production method of the second embodiment, the feedstock oils described in the first embodiment can be used. The first feedstock and the second feedstock are each preferably at least one selected from the group consisting of heavy cracked light oil (HCO), cracked residue oil (CLO), atmospheric residue oil (RC, HPRC), desulfurized residue oil (DSRC), desulfurized vacuum light oil (VHHGO), non-desulfurized vacuum light oil (VGO), non-desulfurized vacuum residue oil (VC), mineral oil (e.g., HG-500 (mineral oil of 500 neutral fraction), etc.), heavy gas oil (HGO), desulfurized heavy gas oil (DS-HGO), desulfurized vacuum residue oil (DS-VC), and deasphalted oil (DAO). The first feedstock and the second feedstock may be the same as each other or different from each other.

[0037] Tables 1 and 2 show the types and properties of the feedstock oils that can be used as the first feedstock and the second feedstock. However, the first feedstock and the second feedstock are not limited thereto. As the first feedstock and the second feedstock, the feedstock oils in Tables 1 and 2 can be used alone or in combination of two or more so as to satisfy Formula (4), Formula (5), Formula (6), and Formula (7). For example, atmospheric residue oil (RC, HPRC), non-desulfurized vacuum residue oil (VC), desulfurized vacuum residue oil (DS-VC), and deasphalted oil (DAO) do not satisfy Formula (6) for kinematic viscosity (75 °C) alone, but can be combined with other feedstock oils to obtain a feedstock oil (the first feedstock or the second feedstock) that satisfies Formula (6) for kinematic viscosity (75 °C).

[0038] [Table 1]

[0039] [Table 2]

[0040] The first feedstock and the second feedstock each preferably have a hydrogen bonding term (δh) represented by the Hansen solubility parameter of 1.5 or less and a dipole-dipole force term (δp) of 4.0 or less. When the hydrogen bonding term (δh) represented by the Hansen solubility parameter is 1.5 or less, waste plastics are likely to be dissolved. The smaller the hydrogen bonding term (δh), the more preferable. When the dipole-dipole force term (δp) represented by the Hansen solubility parameter is 4.0 or less, waste plastics are likely to be dissolved. The smaller the dipole-dipole force term (δp), the more preferable.

[0041] The Hansen solubility parameter is obtained by dividing the solubility parameter introduced by Hildebrand into three components: the London dispersion force term (δd), the dipole-dipole force term (δp), and the hydrogen bonding term (δh), and representing them in three-dimensional space. The London dispersion force term (δd) represents the effect of the London dispersion force, the dipole-dipole force term (δp) represents the effect of the dipole-dipole force, and the hydrogen bonding term (δh) represents the effect of the hydrogen bonding. The definition and calculation of the Hansen solubility parameter are described in "Hansen Solubility Parameters; A Users Handbook (CRC Press, 2007)" by Charles M. Hansen. In the manufacturing method of this embodiment, parameter values described in the literature are used.

[0042] The first feedstock oil and the second feedstock oil can each be used alone or in combination of two or more feedstock oils. When two or more feedstock oils are used in combination, the hydrogen bonding term (δh) of the feedstock oil is taken as the value obtained by averaging the hydrogen bonding terms (δh) of the respective feedstock oils according to the volume ratio. The same applies to the dipole-dipole force term (δp) of the feedstock oil. For example, in the case of a mixed oil obtained by mixing heavy cracked light oil (HCO) with a hydrogen bonding term (δh) of X and cracked residue oil (CLO) with a hydrogen bonding term (δh) of Y at a volume ratio of 6:4 (HCO:CLO), the hydrogen bonding term (δh) of the mixed oil is calculated as (6X + 4Y) / 10.

[0043] <Waste plastics> As the waste plastic used in the manufacturing method of the second embodiment, the waste plastic described in the first embodiment can be used. The waste plastic preferably contains at least one of waste plastic derived from polyethylene and waste plastic derived from polypropylene.

[0044] 〔Aspect 1 of the manufacturing method〕 The manufacturing method of the second embodiment can be implemented using, for example, the processing system 100 shown in FIG. 1 (Aspect 1 of the manufacturing method). In Aspect 1 of the manufacturing method, the case where the same type of raw material oil is used as the first raw material oil and the second raw material oil will be described. In the following description, the expressions using ordinal numbers "first" and "second" are for the purpose of distinguishing members and do not mean order.

[0045] <Overall configuration> The processing system 100 shown in FIG. 1 includes a kneader 20, a first storage tank 60, a line mixer 30 (an example of a mixing device), a second storage tank 40, a residue fluid catalytic cracking unit (RFCC unit 50) (an example of a cracking processing unit), a first transport line 10, a molten waste plastic supply line 15X, a mixed oil transport line 15, a supply line 12X as the first raw material oil supply line, a supply line 13 as the second raw material oil supply line, and a second transport line 14. Further, the processing system 100 includes a waste plastic supply control means 25 and raw material oil supply control means 121, 131.

[0046] (Kneader 20) The kneader 20 prepares molten waste plastic by melting the waste plastic. Molten waste plastic means a solid waste plastic melted into a liquid state. Therefore, the difference between molten waste plastic and solid waste plastic is only the state of the substance. The waste plastic is melted in the kneader 20 to become molten waste plastic, and becomes a molten state, a dissolved state, or a slurry.

[0047] The waste plastic supply control means 25 has a feeder 21 and a feeder controller 24. The waste plastic supply control means 25 controls the supply amount of waste plastic by transmitting a control signal from the feeder controller 24 to the feeder 21 and controlling the operation of the feeder 21. The feeder controller 24 can use a microcomputer or the like. The supply amount of waste plastic means the amount (mass) of waste plastic supplied per unit time. In the kneader 20, a feeder 21 and a hopper 22 are connected via a waste plastic supply line 23. The kneader 20 prepares molten waste plastic by melting the waste plastic supplied from the hopper 22 via the feeder 21. The kneader 20 is not particularly limited, and examples thereof include an extruder (for example, a single-screw extruder and a multi-screw extruder, etc.), a kneader, and a mixer.

[0048] (First transport line 10) The first transport line 10 is connected to the RFCC unit 50 and transports the feedstock oil to the RFCC unit 50. The first transport line 10 has, in order from the upstream side, a branch point B1 that branches into a supply line 12X and a supply line 13, and a confluence point C1 with the second transport line 14. The temperature of the feedstock oil in the first transport line 10 is preferably 80°C or higher and 240°C or lower, more preferably 160°C or higher and 230°C or lower, and can be controlled by temperature control means (for example, a heat exchanger and a heater, etc.) installed at any location on the first transport line 10.

[0049] (Supply line 12X) The supply line 12X branches from the branch point B1 of the first transport line 10, further branches at the branch point B3, and supplies the feedstock oil (corresponding to the first feedstock oil) to the first storage tank 60 via the confluence point C3 with the molten waste plastic supply line 15X. In the middle of the supply line 12X, a heat exchanger HE for controlling the temperature of the first feedstock oil and a feedstock oil supply control means 121 are provided. The raw material oil supply control means 121 includes a control valve 122 and a controller 123. The raw material oil supply control means 121 transmits a control signal from the controller 123 to the control valve 122 and controls the operation of the control valve 122 to control the supply amount of the first raw material oil. The controller 123 can use a microcomputer or the like.

[0050] (Supply line 13) The supply line 13 connects the first transport line 10 and the line mixer 30 and supplies raw material oil (corresponding to the second raw material oil) from the first transport line 10 to the line mixer 30. In the middle of the supply line 13, a heat exchanger HE for controlling the temperature of the second raw material oil and raw material oil supply control means 131 are provided. The raw material oil supply control means 131 includes a control valve 132 and a controller 133. The operation of the raw material oil supply control means 131 is the same as the operation of the raw material oil supply control means 121.

[0051] (Melted waste plastic supply line 15X) The melted waste plastic supply line 15X connects the kneader 20 and the first storage tank 60 and supplies melted waste plastic from the kneader 20 to the first storage tank 60.

[0052] (First storage tank 60) The first storage tank 60 is provided with a rotating blade 80 as stirring means. The rotating blade 80 is connected to a motor (not shown). The first storage tank 60 prepares a melted waste plastic mixed oil by performing the first preparation step described later. Examples of the stirring means include stirring blades such as an impeller and a rotating blade. Examples of the stirring blade include a screw type, a propeller type, a paddle type, and a turbine type, etc., but the shape of the stirring blade is not particularly limited. The stirring means is preferably a stirring blade. Further, the stirring blade is preferably a helical ribbon blade. A gear pump 61 is connected to the first storage tank 60. The pump is not limited to the gear pump 61. The first storage tank 60 may supply the molten waste plastic mixed oil to the line mixer 30 by its own pressure.

[0053] (Mixed oil transport line 15) The mixed oil transport line 15 connects the first storage tank 60 and the line mixer 30, and supplies the molten waste plastic mixed oil prepared in the first storage tank 60 from the first storage tank 60 to the line mixer 30. The temperature of the molten waste plastic mixed oil in the mixed oil transport line 15 is preferably 160°C or higher and 260°C or lower, and can be controlled by temperature control means (such as a heat exchanger and a heater, etc.) installed at any location of the mixed oil transport line 15.

[0054] (Line mixer 30) The line mixer 30 is provided with stirring blades 90 as stirring means. The stirring blades 90 are connected to a motor (not shown). The line mixer 30 prepares a decomposition treatment mixture by performing a second preparation step described later. Examples of the stirring means include the stirring means exemplified in the section of the first storage tank 60. The line mixer 30 is not particularly limited, and an in-line mixer (such as a static mixer, etc.) may be used. The line mixer 30 may be a continuous mixer.

[0055] (Second storage tank 40) The second storage tank 40 stores the decomposition treatment mixture prepared by the line mixer 30. A centrifugal pump 41 is connected to the second storage tank 40. The pump is not limited to the centrifugal pump 41. The second storage tank 40 may supply the decomposition treatment mixture to the RFCC unit 50 by its own pressure. Also, the second storage tank 40 may have stirring means (such as rotating blades, etc.).

[0056] (Second transport line 14) In the case of FIG. 1, after the second transport line 14 transports the decomposition treatment mixture prepared by the line mixer 30 to the second storage tank 40, it transports it to the confluence point C1 of the first transport line 10.

[0057] (RFCC apparatus 50) The RFCC apparatus 50 decomposes the molten waste plastic in the decomposition treatment mixture prepared by the line mixer 30 into liquefied petroleum gases (such as propane, propylene, n-butane, isobutane, and butylene), and decomposes the feedstock oil into FG (gasoline), LCO (light cracked gas oil), and CLO (residual oil), etc. The RFCC apparatus 50 is an embodiment of a fluid catalytic cracking apparatus (FCC apparatus). The RFCC apparatus 50 and the FCC apparatus may be apparatuses commonly used in the field of petroleum refining. Basically, they consist of a reaction tower, a catalyst / product oil separator, a section for removing oil on the catalyst surface, and a catalyst regeneration tower, and the catalyst circulates fluidly within this system. As the catalyst, a catalyst containing synthetic zeolite is usually used. As the process, any process developed by companies such as UOP and IFP may be used. The catalyst used in the RFCC apparatus 50 and the FCC apparatus, as well as the operating conditions, are not particularly limited and can be set as appropriate.

[0058] When the processing system 100 shown in FIG. 1 is used, the manufacturing method of the second embodiment is implemented through the following steps.

[0059] <First Preparation Step> In the first preparation step, the molten waste plastic melted by the kneader 20 and the first feedstock oil supplied from the supply line 12X are mixed in the first storage tank 60 equipped with the rotating blade 80 to prepare a molten waste plastic mixed oil. The first feedstock oil satisfies the above formulas (Equation 4), (Equation 5), (Equation 6), and (Equation 7). The temperature of the first feedstock oil is preferably in the same range as the temperature of the feedstock oil in the first transport line 10.

[0060] (Melting viscosity of molten waste plastic (viscosity A)) The melt viscosity (viscosity A) of the molten waste plastic preferably satisfies the following mathematical formula (Formula 10). 1.0×10 6 mPa·s ≤ viscosity A ≤ 1.0×10 8 mPa·s … (Formula 10) The viscosity A is the melt viscosity (mPa·s) of the molten waste plastic at 200°C. When the melt viscosity (viscosity A) is 1.0×10 6 mPa·s or more, the waste plastic can be melted without applying an excessive load to the kneader 20, so that it becomes easier to control the melting amount of the molten waste plastic. When the melt viscosity (viscosity A) is 1.0×10 8 mPa·s or less, in addition to a certain load on the kneader 20, the waste plastic can be melted by the frictional heat between the molten resins.

[0061] The melting temperature of the waste plastic is preferably 175°C or higher and 260°C or lower, and more preferably 200°C or higher and 240°C or lower. There is. The melting temperature of the waste plastic is the set temperature of the kneader 20.

[0062] In the first preparation step, the mixing in the first storage tank 60 is preferably performed under the conditions of a temperature (mixing temperature) of 175°C or higher and 260°C or lower and a rotational speed of the rotary blade 80 of 3 rpm or higher and 1,000 rpm or lower, and more preferably under the conditions of a temperature of 200°C or higher and 240°C or lower and a rotational speed of the rotary blade 80 of 10 rpm or higher and 500 rpm or lower. The mixing temperature in the first storage tank 60 is the set temperature of the first storage tank 60. The first storage tank 60 is preferably provided with temperature detection means (such as a thermometer, etc.), and the mixing temperature is preferably controlled by temperature control means (such as a heat exchanger and a heater, etc.).

[0063] (The melt viscosity (viscosity B) of the molten waste plastic mixed oil) The melt viscosity (viscosity B) of the molten waste plastic mixed oil prepared in the first preparation step preferably satisfies the following mathematical formula (Formula 20), and more preferably satisfies the following mathematical formula (Formula 21). The measured value of the melt viscosity (viscosity B) of the molten waste plastic mixed oil is the value measured using the molten waste plastic mixed oil in the mixed oil transport line 15 connected to the outlet of the first storage tank 60 in the case of FIG. 1. 1000 mPa·s ≤ viscosity B ≤ 1,000,000 mPa·s …(Equation 20) 1000 mPa·s ≤ viscosity B ≤ 500,000 mPa·s …(Equation 21) (The viscosity B is the melt viscosity (mPa·s) at 200°C.) When the melt viscosity (viscosity B) of the molten waste plastic mixed oil satisfies the above formula (Equation 20), the transportability of the molten waste plastic mixed oil is improved.

[0064] <Second preparation step> The second preparation step is to prepare a decomposition treatment mixture by mixing the molten waste plastic mixed oil prepared in the first preparation step and the second raw material oil supplied from the supply line 13 with a line mixer 30 provided with stirring blades 90. The temperature of the second raw material oil is preferably in the same range as the temperature of the raw material oil in the first transport line 10.

[0065] The second preparation step is preferably carried out under the conditions of a temperature (mixing temperature) of 160°C or higher and 260°C or lower and a rotation speed of the stirring blades 90 of 10 rpm or higher and 20,000 rpm or lower, and more preferably under the conditions of a temperature of 170°C or higher and 240°C or lower and a rotation speed of the stirring blades 90 of 100 rpm or higher and 10,000 rpm or lower. The mixing temperature is the set temperature of the line mixer 30. The line mixer 30 is preferably provided with temperature detection means (such as a thermometer, etc.) and the mixing temperature is controlled by temperature control means (such as a heat exchanger and a heater, etc.).

[0066] (Density, refractive index, kinematic viscosity, and residual ratio of the filter residue of the decomposition treatment mixture) The decomposition treatment mixture prepared in the second preparation step has a density (15 °C) that satisfies the above formula (Equation 1), a refractive index (70 °C) that satisfies the above formula (Equation 2), a kinematic viscosity (200 °C) that satisfies the above formula (Equation 3), and the residual ratio of the filter residue (the filter residue / waste plastic contained in the decomposition treatment mixture) is preferably 0.35 or less by mass ratio. For these measured values of the decomposition treatment mixture, in the case of FIG. 1, they are the values measured using the decomposition treatment mixture in the second transport line 14 connected to the outlet of the line mixer 30.

[0067] <Decomposition treatment mixture storage step> The production method of the second embodiment has a decomposition treatment mixture storage step of storing the decomposition treatment mixture prepared in the second preparation step in the second storage tank 40. The decomposition treatment mixture stored in the second storage tank 40 is transported through the second transport line 14 and merges with the feedstock oil transported through the first transport line 10 at the confluence point C1 and is supplied to the RFCC unit 50.

[0068] 〔Aspect 2 of the production method〕 The production method of the second embodiment can be implemented, for example, using the processing system 200 shown in FIG. 2 (Aspect 2 of the production method).

[0069] <Overall configuration> The processing system 200 shown in FIG. 2 is different from the processing system 100 shown in FIG. 1 in that it includes the supply line 11 as the first feedstock oil supply line, the first storage tank 60 includes the gas vent line 44, and the second storage tank 40 includes the gas vent line 43. Other points are the same as those of the processing system 100. That is, the processing system 200 includes two first feedstock oil supply lines (supply lines 11, 12X). In the following description, the configurations different from those of Aspect 1 of the production method will be described, and the description of the same configurations will be omitted.

[0070] <Supply line 11> The supply line 11 branches off from the branch point B1 of the first transport line 10 and further branches at the branch point B2 to supply the first raw material oil to the outlet side of the kneader 20. A raw material oil supply control means 111 is provided in the middle of the supply line 11. The raw material oil supply control means 111 includes a control valve 112 and a controller 113. The operation of the raw material oil supply control means 111 is the same as that of the raw material oil supply control means 121.

[0071] When the processing system 200 shown in FIG. 2 is used, the manufacturing method of the second embodiment is carried out through the following steps.

[0072] <First Preparation Step> In the first preparation step, the molten waste plastic prepared by the kneader 20, the first raw material oil supplied from the supply line 11 to the outlet side of the kneader 20, and the first raw material oil supplied from the supply line 12 are mixed in the first storage tank 60 to prepare a molten waste plastic mixed oil. The temperature of the first raw material oil is preferably in the same range as the temperature of the raw material oil in the first transport line 10.

[0073] (First Gas Discharge Step) The first preparation step includes a first gas discharge step. The first gas discharge step is a step of discharging the gas (for example, water vapor, volatile organic compounds, etc.) generated from the molten waste plastic mixed oil from the first storage tank 60 through the gas discharge line 44 (an example of gas discharge means).

[0074] (Second Gas Discharge Step) The decomposition treatment mixture storage step includes a second gas discharge step. The second gas discharge step is a step of discharging the gas (for example, water vapor, volatile organic compounds, etc.) generated from the decomposition treatment mixture from the second storage tank 40 through the gas discharge line 43 (an example of gas discharge means).

[0075] 〔Aspect 3 of the Manufacturing Method〕 The manufacturing method of the second embodiment can be carried out, for example, using the processing system 300 shown in FIG. 3 (Aspect 3 of the manufacturing method).

[0076] <Overall Configuration> The processing system 300 shown in FIG. 3 is different from the processing system 100 shown in FIG. 1 in that it is provided with an additional feedstock oil supply line 70X. Other aspects are the same as those of the processing system 100. In the following description, the configurations different from those of Embodiment 1 of the manufacturing method will be described, and the description of the same configurations will be omitted.

[0077] <Additional Feedstock Oil Supply Line 70X> The additional feedstock oil supply line 70X supplies additional feedstock oil to the outlet side of the kneader 20. As the additional feedstock oil, a feedstock oil the same as or different from the first feedstock oil and the second feedstock oil can be used. An additional feedstock supply control means 171 is provided in the middle of the additional feedstock oil supply line 70X. The additional feedstock supply control means 171 includes a regulating valve 172 and a controller 173. The operation of the additional feedstock supply control means 171 is the same as the operation of the feedstock oil supply control means 121. The temperature of the additional feedstock oil in the additional feedstock oil supply line 70X is preferably in the same range as the temperature of the feedstock oil in the first transport line 10.

[0078] When the processing system 300 shown in FIG. 3 is used, the manufacturing method of the second embodiment is carried out through the following steps.

[0079] <First Preparation Step> In the first preparation step, a molten waste plastic mixture oil is prepared by mixing the molten waste plastic melted by the kneader 20, the additional feedstock oil supplied from the additional feedstock oil supply line 70X, and the first feedstock oil supplied from the supply line 12X in the first storage tank 60.

[0080] <Second Preparation Step> The second preparation step is carried out in the same manner as in Embodiment 1 of the manufacturing method.

[0081] 〔Embodiments 4 to 7 of the Manufacturing Method〕 The processing systems 400, 500, 600, 700 shown in FIGS. 5 to 8 are examples including specific surface area increasing means for increasing the specific surface area of molten waste plastic.

[0082] The specific surface area increasing means is preferably at least one of a stretching plate, a perforated plate, a pump, and a split supply line. As the stretching plate, for example, the stretching plate shown in FIG. 4A can be mentioned. The stretching plate shown in FIG. 4A has a substantially circular main body 70A and a plurality of openings 71. The openings 71 are sheet-shaped. The shape of the main body 70A is not particularly limited. The shape and number of the openings 71 are also not particularly limited. As the perforated plate, for example, the perforated plate shown in FIG. 4B can be mentioned. The perforated plate shown in FIG. 4B has a substantially circular main body 70B and a plurality of holes 72. The shape of the main body 70B is not particularly limited. The shape and number of the holes 72 are also not particularly limited. The pump is not particularly limited. As the split supply line, for example, one or more branch lines split from the molten waste plastic supply line can be mentioned. The specific surface area increasing means is preferably a means for increasing the specific surface area of molten waste plastic so that the specific surface area of the molten waste plastic becomes 400 m 2 / m 3 or more.

[0083] Since each processing system includes the specific surface area increasing means, the molten waste plastic is subdivided and supplied to the first storage tank 60, so that the molten waste plastic is easily dissolved in the first raw material oil in the first storage tank 60. As a result, a molten waste plastic mixed oil with improved miscibility between the first raw material oil and the molten waste plastic can be obtained.

[0084] 〔Aspect 4 of the manufacturing method〕 The manufacturing method of the second embodiment can be implemented, for example, using the processing system 400 shown in FIG. 5 (Aspect 4 of the manufacturing method). The processing system 400 is an example including a stretching plate or a perforated plate as the specific surface area increasing means.

[0085] <Overall configuration> The processing system 400 shown in FIG. 5 is different from the processing system 100 in that the molten waste plastic supply line 15X is provided with the specific surface area enlarging means 70, and the first raw material oil is directly supplied from the supply line 12 to the first storage tank 60. Other points are the same as those of the processing system 100. In the following description, the configurations different from those of Embodiment 1 of the manufacturing method will be described, and the description of the same configurations will be omitted.

[0086] (Specific surface area enlarging means) As the specific surface area enlarging means 70, for example, the stretching plate shown in FIG. 4A or the porous plate shown in FIG. 4B can be preferably used. FIG. 4A corresponds to a cross-sectional view taken along line I-I of FIG. 5 when the specific surface area enlarging means 70 is a stretching plate. FIG. 4B corresponds to a cross-sectional view taken along line I-I of FIG. 5 when the specific surface area enlarging means 70 is a porous plate.

[0087] When the processing system 400 shown in FIG. 5 is used, the manufacturing method of the second embodiment is carried out through the following steps.

[0088] <Specific surface area enlarging step> The molten waste plastic discharged from the kneader 20 passes through the specific surface area enlarging means 70, whereby the specific surface area is enlarged.

[0089] <First preparation step> In the first preparation step, the molten waste plastic with an enlarged specific surface area by the specific surface area enlarging means 70 and the first raw material oil supplied from the supply line 12 are mixed in the first storage tank 60 to prepare a molten waste plastic mixed oil.

[0090] <Second preparation step> The second preparation step is carried out in the same manner as in Embodiment 1 of the manufacturing method.

[0091] 〔Embodiment 5 of the manufacturing method〕 The manufacturing method of the second embodiment can be carried out, for example, using the processing system 500 shown in FIG. 6 (Embodiment 5 of the manufacturing method). The processing system 500 is an example provided with a split supply line as the specific surface area enlarging means.

[0092] <Overall Configuration> The processing system 500 shown in FIG. 6 is different from the processing system 200 shown in FIG. 2 in that the molten waste plastic supply line 15X includes a plurality of divided supply lines 73, 74, 731, 732 (an example of specific surface area increasing means), and the first raw material oil is directly supplied from the supply line 12 to the first storage tank 60. Other points are the same as those of the processing system 200. In the following description, the configurations different from those of Embodiment 2 of the manufacturing method will be described, and the description of the same configurations will be omitted.

[0093] (Specific surface area increasing means) In the case of FIG. 6, the plurality of divided supply lines 73, 74, 731, 732 correspond to the specific surface area increasing means. The divided supply lines 73, 74 are branched from the molten waste plastic supply line 15X at the branch point B10, and the divided supply line 73 is further branched into divided supply lines 731, 732. The number of divided supply lines is not limited to these.

[0094] When the processing system 500 shown in FIG. 6 is used, the manufacturing method of the second embodiment is carried out through the following steps.

[0095] <Specific surface area increasing step> The molten waste plastic discharged from the kneader 20 flows through the molten waste plastic supply line 15X and the plurality of divided supply lines 73, 74, 731, 732, thereby increasing the specific surface area of the molten waste plastic.

[0096] <First preparation step> In the first preparation step, the molten waste plastic (molten waste plastic with an increased specific surface area) supplied from the molten waste plastic supply line 15X and the plurality of divided supply lines 73, 74, 731, 732 and the first raw material oil supplied from the supply line 12 are mixed in the first storage tank 60 to prepare a molten waste plastic mixed oil.

[0097] <Second preparation step> The second preparation step is carried out in the same manner as in Mode 2 of the manufacturing method.

[0098] 〔Mode 6 of the manufacturing method〕 The manufacturing method of the second embodiment can be carried out using, for example, the processing system 600 shown in FIG. 7 (Mode 6 of the manufacturing method). The processing system 600 is an example including a pump as the specific surface area increasing means.

[0099] <Overall configuration> The processing system 600 shown in FIG. 7 is different from the processing system 300 shown in FIG. 3 in that it has a circulation line 91 through which a part of the molten waste plastic mixed oil circulates, the circulation line 91 includes a pump 75 (an example of the specific surface area increasing means), the molten waste plastic supply line 15Y is connected to the circulation line 91, and the first raw material oil is directly supplied from the supply line 12 to the first storage tank 60. Other points are the same as those of the processing system 300. In the following description, the configurations different from those in Mode 3 of the manufacturing method will be described, and the description of the same configurations will be omitted.

[0100] (Specific surface area increasing means) In the case of FIG. 7, the pump 75 corresponds to the specific surface area increasing means.

[0101] When the processing system 600 shown in FIG. 7 is used, the manufacturing method of the second embodiment is carried out through the following steps.

[0102] (Specific surface area increasing step) The molten waste plastic flowing through the molten waste plastic supply line 15Y and a part of the molten waste plastic mixed oil prepared in the first storage tank 60 are joined at the junction point C12. The mixture (a mixture of molten waste plastic and molten waste plastic mixed oil) joined at the junction point C12 passes through the pump 75, whereby the specific surface area of the molten waste plastic contained in the mixture is increased.

[0103] (First preparation step) The mixture containing the molten waste plastic with an enlarged specific surface area is supplied from the mixed oil supply port 102 of the circulation line 91 to the first storage tank 60. The first preparation step prepares a molten waste plastic mixed oil by mixing the mixture supplied from the mixed oil supply port 102 of the circulation line 91 and the first feedstock oil supplied from the supply line 12 in the first storage tank 60.

[0104] Note that the specific surface area enlargement step and the first preparation step during the operation of the treatment system 600 are carried out as follows. The molten waste plastic flowing through the molten waste plastic supply line 15Y and the first feedstock oil supplied from the supply line 12 and stored in the first storage tank 60 are combined at the confluence point C12 and then pass through the pump 75. By passing through this pump 75, the specific surface area of the molten waste plastic is enlarged (specific surface area enlargement step). The molten waste plastic with an enlarged specific surface area is supplied from the mixed oil supply port 102 of the circulation line 91 to the first storage tank 60. The first preparation step prepares a molten waste plastic mixed oil by mixing the molten waste plastic supplied from the mixed oil supply port 102 of the circulation line 91 and the first feedstock oil supplied from the supply line 12 in the first storage tank 60. A part of the prepared molten waste plastic mixed oil is discharged into the circulation line 91 and combined with the molten waste plastic flowing through the molten waste plastic supply line 15Y at the confluence point C12.

[0105] <Second Preparation Step> The second preparation step is carried out in the same manner as in Mode 3 of the manufacturing method.

[0106] 〔Mode 7 of the Manufacturing Method〕 The manufacturing method of the second embodiment can be carried out, for example, using the treatment system 700 shown in FIG. 8 (Mode 7 of the manufacturing method). The treatment system 700 is an example equipped with a pump as the specific surface area enlargement means.

[0107] <Overall Configuration> The processing system 700 shown in FIG. 8 is different from the processing system 600 shown in FIG. 7 in that the circulation line 92 is connected to the supply line 12 of the first feedstock oil. Other aspects are the same as those of the processing system 600. In the following description, configurations different from those of Embodiment 6 of the manufacturing method will be described, and descriptions of the same configurations will be omitted.

[0108] When the processing system 700 shown in FIG. 8 is used, the manufacturing method of the second embodiment is implemented through the following steps.

[0109] <Specific surface area enlargement step> The specific surface area enlargement step is implemented in the same manner as in Embodiment 6 of the manufacturing method.

[0110] <First preparation step> The mixture containing the molten waste plastic with an enlarged specific surface area (a mixture of molten waste plastic and molten waste plastic mixed oil) flows through the circulation line 92 and then merges with the first feedstock oil at the confluence point C13 with the supply line 12 and is supplied to the first storage tank 60. The first preparation step prepares the molten waste plastic mixed oil by mixing the mixture (a mixture of molten waste plastic and molten waste plastic mixed oil) and the first feedstock oil in the first storage tank 60.

[0111] <Second preparation step> The second preparation step is implemented in the same manner as in Embodiment 6 of the manufacturing method.

[0112] Note that the specific surface area enlargement step and the first preparation step during the operation of the processing system 700 are implemented as follows. The specific surface area enlargement step is the same as the specific surface area enlargement step during the operation of the processing system 600. In the first preparation step, a molten waste plastic mixture oil is prepared by mixing the molten waste plastic (molten waste plastic with an increased specific surface area) and the first feedstock oil that are combined at the confluence point C13 in the first storage tank 60. A part of the prepared molten waste plastic mixture oil is discharged into the circulation line 92 and combined with the molten waste plastic flowing through the molten waste plastic supply line 15Y at the confluence point C12.

[0113] 〔One Aspect of the First Storage Tank〕 In Aspects 1 to 7 of the manufacturing method, the first storage tank preferably includes a helical ribbon blade as a stirring means. FIG. 9 is a top view and a front view of the first storage tank 60A when the stirring means is a stirring blade and the stirring blade is a helical ribbon blade. The left figure in FIG. 9 represents the top view, and the right figure represents the front view. The first storage tank 60A shown in FIG. 9 includes a dissolving tank 65, a stirring blade (helical ribbon blade) 62, a shaft 63, and a pair of support rods 64. The reference signs in FIG. 9 represent the following. · D... Inner diameter of the dissolving tank · d0... Stirring blade diameter of the stirring blade · d1... Central cavity diameter of the stirring blade · d S1 ... Shaft diameter of the shaft · d S2 ... Shaft diameter of the support rod · h... Height of the stirring blade · Dy... Clearance between the dissolving tank and the stirring blade · TL... Tandem line · L... Height of the dissolving tank · w... Blade width of the stirring blade

[0114] In one aspect of the first storage tank 60A, it is preferable that the blade width w (m) of the stirring blade satisfies the following mathematical formulas (Formula X1) and (Formula X2) when the inner diameter of the dissolving tank is D (m) and the stirring blade diameter of the stirring blade is d0 (m). w ≧ 0.10D... (Formula X1) d0 ≧ 0.85D... (Formula X2)

[0115] In one aspect of the first storage tank 60A, the clearance Dy (m) between the dissolution tank and the stirring blade preferably satisfies the following mathematical formulas (Formula Y1) and (Formula Y2), where D (m) is the inner diameter of the dissolution tank and d0 (m) is the stirring blade diameter of the stirring blade. Dy = (D - d0) / 2 …(Formula Y1) Dy ≤ 0.075D …(Formula Y2)

[0116] In one aspect of the first storage tank 60A, when the height of the dissolution tank is L (m) and the inner diameter of the dissolution tank is D (m), L / D preferably satisfies the following mathematical formula (Formula Z). 0.8 ≤ L / D ≤ 1.6…Mathematical formula (Formula Z)

[0117] An example of the dimensions of each member constituting the first storage tank 60A is shown in Table 3.

[0118]

Table 3

[0119] Explanation of Table 3 ·V represents the volume [m 3 of the dissolution tank.

[0120] 〔One aspect of the dissolution device〕 The processing system shown in FIGS. 5 to 8 can be equipped with any of the dissolution devices shown in FIGS. 10 to 14. FIGS. 10 to 14 are schematic diagrams of an example of the dissolution device. The dissolution device shown in FIGS. 10 to 14 will be described.

[0121] (Dissolution device 1) The dissolution device 1 shown in FIG. 10 is provided in the processing system 400 shown in FIG. 5. The reference signs correspond to those in FIG. 5. The dissolution device 1 includes a first storage tank 60 provided with stirring means 80, a molten waste plastic supply line 15X, a raw material oil supply line 12, specific surface area expansion means 70, and a mixed oil transport line 15.

[0122] (Dissolution device 1B) The melting device 1B shown in FIG. 11 is provided in the processing system 500 shown in FIG. 6. The reference numerals correspond to those in FIG. 6. The melting device 1B is different from the melting device 1 shown in FIG. 10 in that the specific surface area enlarging means are the divided supply lines 73, 74, 731, and 732. Other points are the same as those of the melting device 1.

[0123] (Melting device 1C) The melting device 1C shown in FIG. 12 is provided in the processing system 600 shown in FIG. 7. The reference numerals correspond to those in FIG. 7. The melting device 1C includes a first storage tank 60 provided with stirring means 80, a molten waste plastic supply line 15Y, a raw material oil supply line 12, a circulation line 91 for circulating a part of the molten waste plastic mixed oil, a mixed oil transport line 15, and a pump 75 disposed in the circulation line 91 and serving as specific surface area enlarging means for enlarging the specific surface area of the molten waste plastic. Further, the first storage tank 60 includes a plurality of discharge ports 101A and 101B for discharging the molten waste plastic mixed oil obtained in the first storage tank 60, and a mixed oil supply port 102 for supplying a part of the molten waste plastic mixed oil back into the first storage tank 60 via the circulation line 91. The circulation line 91 connects the discharge port 101B of the first storage tank 60 and the mixed oil supply port 102.

[0124] (Melting device 1D) The melting device 1D shown in FIG. 13 is provided in the processing system 700 shown in FIG. 8. The reference numerals correspond to those in FIG. 8. The melting device 1D shown in FIG. 13 is different from the melting device 1C shown in FIG. 12 in that the downstream side of the circulation line 92 is connected to the raw material oil supply line 12. Other points are the same as those of the melting device 1C.

[0125] (Melting device 1A) The melting device 1A shown in FIG. 14 is different from the melting device 1 shown in FIG. 10 in that the raw material oil supply line 12X is not directly connected to the first storage tank 60 but is connected to the molten waste plastic supply line 15X at the confluence point C3. Other points are the same as those of the melting device 1.

[0126] The processing system 400 shown in FIG. 5 may include the melting device 1B shown in FIG. 11, the melting device 1C shown in FIG. 12, or the melting device 1D shown in FIG. 13 instead of the melting device 1. The processing system 500 shown in FIG. 6 may include the melting device 1 shown in FIG. 10, the melting device 1C shown in FIG. 12, or the melting device 1D shown in FIG. 13 instead of the melting device 1B. The processing system 600 shown in FIG. 7 may include the melting device 1 shown in FIG. 10, the melting device 1B shown in FIG. 11, or the melting device 1D shown in FIG. 13 instead of the melting device 1C. The processing system 700 shown in FIG. 8 may include the melting device 1 shown in FIG. 10, the melting device 1B shown in FIG. 11, or the melting device 1C shown in FIG. 12 instead of the melting device 1D.

[0127] In addition, the processing systems 400, 500, 600, and 700 shown in FIGS. 5 to 8 may include the melting device 1A shown in FIG. 14 instead of the melting devices they each include. In the case of these aspects, as shown in FIG. 14, the raw material oil supply line 12X is not directly connected to the first storage tank 60, but is connected to an arbitrary location on the molten waste plastic supply line 15X.

[0128] 〔Other aspects of the manufacturing method〕 In aspects 1 to 7 of the manufacturing method, molten waste plastic mixed oil may be prepared using two or more first storage tanks 60. The arrangement of the first storage tanks 60 is not particularly limited. The two or more first storage tanks 60 may be the same as or different from each other. In aspects 1 to 7 of the manufacturing method, a decomposition treatment mixture may be prepared using two or more line mixers 30. The arrangement of the line mixers 30 is not particularly limited. The two or more line mixers 30 may be the same as or different from each other. In aspects 1 to 7 of the manufacturing method, the decomposition treatment mixture prepared by the line mixer 30 may be circulated through a circulation line to at least one of the first storage tank 60 and the line mixer 30. In Embodiments 1 to 7 of the manufacturing method, additional feedstock oil may be supplied to the line mixer 30. In Embodiments 1 to 7 of the manufacturing method, molten waste plastic may be prepared using two or more kneaders 20. The arrangement of the kneaders 20 is not particularly limited. The two or more kneaders 20 may be the same as or different from each other.

[0129] In Embodiments 1 to 7 of the manufacturing method, the decomposition treatment mixture prepared by the line mixer 30 may be supplied to the RFCC unit without being stored in the second storage tank. In Embodiments 1 to 7 of the manufacturing method, the decomposition treatment mixture prepared by the line mixer 30 may be directly supplied from the second transport line to the RFCC unit. In Embodiments 1 to 7 of the manufacturing method, a known mixing device may be used instead of the line mixer 30. In Embodiments 1 to 7 of the manufacturing method, instead of the RFCC unit 50, a known decomposition treatment device used in the field of petroleum refining, for example, may be used.

[0130] The decomposition treatment mixture of the first embodiment only needs to satisfy Formulas (Formula 1) to (Formula 3) and the residual ratio of the filter residue is 0.35 or less by mass ratio, so it does not necessarily have to be produced by Embodiments 1 to 7 of the above manufacturing method. For example, in the first storage tank, solid waste plastic and feedstock oil having specific properties are heated, and while melting the waste plastic, it may be mixed with the feedstock oil to produce a decomposition treatment mixture.

Examples

[0131] Hereinafter, examples according to the present invention will be described. The present invention is not limited by these examples.

[0132] 〔Example 1〕 Using polyethylene as the waste plastic, 4 g of waste plastic and 196 g of DSRC as the feedstock oil were introduced into a homogenizer, and the waste plastic was melted and mixed with DSRC under the following conditions to prepare a decomposition treatment mixture. As the DSRC, the feedstock oil having the properties shown in Table 1 above was used. (Melting and mixing conditions) · Homogenizer: T.K. Homodyne 2.5 type manufactured by Tokushu Kika Co., Ltd. · Blade: Turbine blade · Temperature: 200 °C · Rotation speed: 900 rpm

[0133] [Example 2] A decomposition treatment mixture was prepared in the same manner as in Example 1, except that the raw material oil was changed to HCO. As the HCO, a raw material oil having the properties shown in Table 1 above was used.

[0134] [Example 3] A decomposition treatment mixture was prepared in the same manner as in Example 1, except that the raw material oil was changed to HG-500. As the HG-500, a raw material oil having the properties shown in Table 2 above was used.

[0135] [Comparative Example 1] A decomposition treatment mixture was prepared in the same manner as in Example 1, except that the raw material oil was changed to benzyl alcohol. The properties of benzyl alcohol are as follows. · Density (15 °C): 1.049 g / cm 3 · Refractive index (70 °C): 1.518 · Kinematic viscosity (75 °C): 1.52 mm 2 / s · Molecular weight: 108 g / mol

[0136] [Evaluation] The properties of the decomposition treatment mixture obtained in each example were measured. The results are shown in Table 4.

[0137] (Density, refractive index and kinematic viscosity) The density (15 °C), refractive index (70 °C) and kinematic viscosity (200 °C) of the decomposition treatment mixture were measured by the methods described above.

[0138] (Residual ratio of the filtrate) 200 g of the decomposition treatment mixture was passed through a 40-mesh filter by its own weight under the conditions of normal temperature and pressure (25 °C, 1 atm). The residual ratio of the filtrate to the waste plastic contained in the decomposition treatment mixture (the filtrate / the waste plastic contained in the decomposition treatment mixture) (mass ratio) was calculated by the method described above. In this evaluation, the mass of the waste plastic contained in the decomposition treatment mixture is 4 g.

[0139] [Table 4]

[0140] The decomposition treatment mixtures of Examples 1 to 3 satisfy the respective mathematical formulas (Equation 1) to (Equation 3) for density (15 °C), refractive index (70 °C), and kinematic viscosity (200 °C). The decomposition treatment mixtures of Examples 1 to 3 having such properties showed a significantly low residual ratio of the filtrate (all 0.35 or less). On the other hand, since the kinematic viscosity of the decomposition treatment mixture of Comparative Example 1 does not satisfy the mathematical formula (Equation 3), the residual ratio of the filtrate showed a high value (1.00). From the above results, it can be seen that the decomposition treatment mixtures of Examples 1 to 3 have the molten waste plastic and the raw material oil sufficiently mixed. Therefore, by decomposing the decomposition treatment mixtures of Examples 1 to 3 with a decomposition treatment apparatus, the decomposability of the waste plastic can be improved.

Industrial Applicability

[0141] The waste plastic decomposition treatment mixture of the present invention can increase the utilization efficiency of the chemical recycling of waste plastics, and thus is industrially applicable.

Explanation of Symbols

[0142] 1, 1A, 1B, 1C, 1D... dissolving device, 10... first transport line, 11, 12, 12X... supply line (first raw material oil supply line), 13... supply line (second raw material oil supply line), 14... second transport line, 15X, 15Y... molten waste plastic supply line, 15... mixed oil transport line, 20... kneader, 21... feeder, 22... hopper, 23... waste plastic supply line, 24... feeder controller, 25... waste plastic supply control means, 30... line mixer, 40... second storage tank, 41... centrifugal pump, 43, 44... gas vent line, 50... RFCC unit, 60, 60A... first storage tank, 61... gear pump, 62... stirring blade, 63... shaft, 64... pair of support rods, 65... dissolving tank, 70... specific surface area enlarging means, 70A, 70B... body, 71... opening, 72... hole, 73, 74, 731, 732... divided supply line, 70X... additional raw material oil supply line, 75... pump, 80... rotating blade, 90... stirring vane, 91, 92... circulation line, 100, 200, 300, 400, 500, 600, 700... processing system, 102... mixed oil supply port, 111, 121, 131, 171... raw material oil supply control means, 112, 122, 132, 172... regulating valve, 113, 123, 133, 173... controller, HG... heat exchanger.

Claims

1. A mixture for decomposing waste plastic by a waste plastic decomposition apparatus, comprising: The mixture for decomposing waste plastic: Contains molten waste plastic which is a melt of the waste plastic and a raw material oil, Satisfies the following mathematical formula (Formula 1), mathematical formula (Formula 2) and mathematical formula (Formula 3), When the mixture for decomposing waste plastic is passed through a 40-mesh filter, the residual ratio of the filtrate to the waste plastic contained in the mixture for decomposing waste plastic (the filtrate / the waste plastic contained in the mixture for decomposing waste plastic) is 0.35 or less by mass ratio. Mixture for decomposing waste plastic. 0.850 g / cm ３ ≤ Density (15 °C) ≤ 1.150 g / cm ３ … (Equation 1) 1.400 ≤ Refractive index (70 °C) ≤ 1.650 … (Formula 2) 4.0 mm ２ / s ≤ kinematic viscosity (200 °C) ≤ 20.0 mm ２ / s … (Equation 3)

2. In the mixture for decomposing waste plastic according to Claim 1, The raw material oil is at least one selected from the group consisting of heavy cracked light oil, cracked residue oil, atmospheric residue oil, desulfurized residue oil, desulfurized vacuum light oil, non-desulfurized vacuum light oil, non-desulfurized vacuum residue oil, mineral oil, heavy light oil, desulfurized heavy light oil, desulfurized vacuum residue oil, and decanted oil. Mixture for decomposing waste plastic.

3. In the mixture for decomposing waste plastic according to Claim 1 or Claim 2, The waste plastic contains at least one of waste plastic derived from polyethylene and waste plastic derived from polypropylene. Mixture for decomposing waste plastic.

4. A method for producing a mixture for decomposing waste plastic by a waste plastic decomposition apparatus, comprising: A first preparation step of preparing a molten waste plastic mixed oil by mixing a molten waste plastic which is a melt of the waste plastic and a first raw material oil; A second preparation step of preparing a mixture for decomposing waste plastic by mixing the molten waste plastic mixed oil prepared in the first preparation step and a second raw material oil. The first raw material oil and the second raw material oil each satisfy the following mathematical formula (Formula 4), mathematical formula (Formula 5), mathematical formula (Formula 6) and mathematical formula (Formula 7). When the mixture for decomposing waste plastic prepared in the second preparation step is passed through a 40-mesh filter, the residual ratio of the filtrate to the waste plastic contained in the mixture for decomposing waste plastic (the filtrate / the waste plastic contained in the mixture for decomposing waste plastic) is 0.35 or less by mass ratio. The first raw material oil and the second raw material oil are the same as or different from each other. Method for producing a mixture for waste plastic decomposition treatment. 0.850 g / cm ３ ≤ density (15 °C) ≤ 1.150 g / cm ３ … (Equation 4) 1.400 ≤ refractive index (70 °C) ≤ 1.650... (Equation 5) 3.0 mm ２ / s ≤ kinematic viscosity (75 °C) ≤ 55.0 mm ２ / s … (Equation 6) 240 g / mol ≤ molecular weight ≤ 1000 g / mol... (Equation 7)

5. In the method for producing a mixture for waste plastic decomposition treatment according to Claim 4, the first raw material oil and the second raw material oil each have a hydrogen bonding term (δh) represented by the Hansen solubility parameter of 1.5 or less and a dipole-dipole force term (δp) of 4.0 or less. Method for producing a mixture for waste plastic decomposition treatment.

6. In the method for producing a mixture for waste plastic decomposition treatment according to Claim 4 or Claim 5, the first raw material oil and the second raw material oil are each at least one selected from the group consisting of heavy cracked light oil, cracked residue oil, atmospheric residue oil, desulfurized residue oil, desulfurized vacuum light oil, non-desulfurized vacuum light oil, non-desulfurized vacuum residue oil, mineral oil, heavy light oil, desulfurized heavy light oil, desulfurized vacuum residue oil, and decanted oil. Method for producing a mixture for waste plastic decomposition treatment.

7. In the method for producing a mixture for waste plastic decomposition treatment according to any one of Claims 4 to 6, the waste plastic contains at least one of waste plastic derived from polyethylene and waste plastic derived from polypropylene. Method for producing a mixture for waste plastic decomposition treatment.

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