JP7626650B2 - Method for manufacturing mixture for waste plastic decomposition treatment - Google Patents

Description

The present invention relates to a method for producing a mixture for decomposing waste plastics.

The low rate of effective utilization of waste plastics and environmental pollution caused by marine plastics have become global issues.
One method for recycling waste plastics is chemical recycling, and various studies have been conducted on chemical recycling technology.

For example, Patent Document 1 discloses a method that includes melting a plastic material (1) to form a plastic melt, degassing the plastic melt, and then sending the plastic melt to a depolymerization reactor (3), and adding a fraction obtained from crude oil as a solvent (6) to the plastic melt, thereby reducing the viscosity of the plastic melt solution supplied to the depolymerization reactor (3) below the viscosity of the plastic melt.

Patent Document 2 discloses a method for cracking and producing a hydrocarbon polymer in a fluid catalytic cracking (FCC) unit, characterized in that a mixture of the hydrocarbon polymer and a hydrocarbon oil selected from FCC gasoline, light cracked gas oil, heavy cracked gas oil, cracked residual oil, atmospheric residual oil, and desulfurized residual oil is mixed with FCC feedstock oil and supplied to the FCC unit.

JP 2014-518906 A JP 2002-294251 A

Patent Document 1 describes that the viscosity of a plastic melt solution is reduced by adding a solvent to the plastic melt. However, since a plastic melt solution to which a solvent has simply been added is prone to separation, the method described in Patent Document 1 may result in a plastic melt solution in an insufficiently mixed state being supplied to a depolymerization reactor. As a result, the decomposability of the plastic material may not be sufficiently improved.
Incidentally, Patent Document 1 discloses a method for mixing plastic materials in which molten plastic is continuously discharged from a depolymerization reactor by a pump and recirculated back to the depolymerization reactor. However, since this method recirculates the molten plastic to be decomposed, it is considered difficult to improve the decomposition ability of the plastic materials relative to the molten plastic supplied to the depolymerization reactor.
Patent Document 2 discloses a method for cracking a mixture of a hydrocarbon polymer and a hydrocarbon oil using an FCC unit capable of cracking high boiling fractions in crude oil into high added value gasoline and the like by catalytic reaction, but Patent Document 2 does not pay any attention to the solubility of the hydrocarbon polymer in the hydrocarbon oil, specifically, the mixability of the hydrocarbon polymer and the hydrocarbon oil. Therefore, even in the method described in Patent Document 2, the mixture in a state of insufficient mixability may be mixed with FCC feedstock oil and supplied to the FCC unit. As a result, the decomposition ability of the hydrocarbon polymer may not be sufficiently improved.

The present invention aims to provide a method for producing a mixture for waste plastic decomposition processing that can improve the decomposition ability of waste plastic.

According to one aspect of the present invention, there is provided a method for producing a mixture for waste plastic decomposition treatment for decomposing waste plastic in a decomposition treatment device, comprising the steps of:
A first preparation step of preparing a molten waste plastic mixed oil by mixing the molten waste plastic melted in the melting device and the raw material oil supplied from one or more first supply lines in a stirring tank equipped with a first stirring means;
A second preparation step of preparing a mixture for waste plastic decomposition processing by mixing the molten waste plastic mixed oil prepared in the first preparation step with raw material oil supplied from one or more second supply lines in a line mixer equipped with a second stirring means,
The melt viscosity of the molten waste plastic is viscosity A, the melt viscosity of the molten waste plastic mixed oil prepared in the first preparation step is viscosity B, and the melt viscosity of the waste plastic decomposition treatment mixture prepared in the second preparation step is viscosity C. The viscosity A satisfies the following formula (Mathematical Formula 1), the viscosity C satisfies the following formula (Mathematical Formula 2), and the viscosity ratio of the viscosity C to the viscosity B (the viscosity C/the viscosity B) is the following formula (Mathematical Formula 3). The first preparation step and the second preparation step are carried out so that
A method for producing a mixture for waste plastic decomposition processing is provided, in which when the mixture for waste plastic decomposition processing is passed through a 40 mesh filter, the passing rate of the mixture for waste plastic decomposition processing through the filter is 90 mass% or more.
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
5.0mPa・s<Viscosity C≦50mPa・s…(Equation 2)
Viscosity C/Viscosity B≦1/20…(Math. 3)
(In the above formulas (1) to (3), the viscosity A, the viscosity B, and the viscosity C are all melt viscosities (mPa·s) at 200° C.)

According to one aspect of the present invention, there is provided a method for producing a mixture for waste plastic decomposition treatment for decomposing waste plastic in a decomposition treatment device, comprising the steps of:
A first preparation step of preparing a molten waste plastic mixed oil by mixing the molten waste plastic melted in the melting device and the raw material oil supplied from one or more first supply lines in a stirring tank equipped with a first stirring means;
A second preparation step of preparing a mixture for waste plastic decomposition processing by mixing the molten waste plastic mixed oil prepared in the first preparation step with raw material oil supplied from one or more second supply lines in a line mixer equipped with a second stirring means,
When the melt viscosity of the molten waste plastic is viscosity A, the melt viscosity of the molten waste plastic mixed oil prepared in the first preparation step is viscosity B, and the melt viscosity of the waste plastic decomposition treatment mixture prepared in the second preparation step is viscosity C, the viscosity A satisfies the following formula (Mathematical Formula 1), the viscosity ratio of the viscosity B to the viscosity A (the viscosity B / the viscosity A) satisfies the following formula (Mathematical Formula 2X), and the viscosity ratio of the viscosity C to the viscosity B (the viscosity C / the viscosity B) satisfies the following formula (Mathematical Formula 3). The first preparation step and the second preparation step are carried out so that
A method for producing a mixture for waste plastic decomposition processing is provided, in which when the mixture for waste plastic decomposition processing is passed through a 40 mesh filter, the passing rate of the mixture for waste plastic decomposition processing through the filter is 90 mass% or more.
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
Viscosity B/Viscosity A≦1/1…(Several 2X)
Viscosity C/Viscosity B≦1/20…(Math. 3)
(In the above formulas (1), (2X), and (3), the viscosity A, the viscosity B, and the viscosity C are all melt viscosities (mPa·s) at 200° C.)

In one embodiment of the method for producing a mixture for waste plastic decomposition processing according to the present invention, it is preferable that the first supply line and the second supply line are the same supply line or different supply lines.

In one embodiment of the method for producing a mixture for waste plastic decomposition processing according to the present invention, the first preparation step prepares the molten waste plastic mixed oil using 1 to 10 stirring tanks, and when there are two or more stirring tanks, it is preferable that the two or more stirring tanks are arranged in series, in parallel, or in a combination of series and parallel.

In one embodiment of the present invention, a method for producing a mixture for waste plastic decomposition treatment is provided.
The first preparation step includes a first circulating oil supply step of supplying at least one of a first circulating oil and a second circulating oil to at least one of the stirring tanks via a circulation line,
The first circulating oil is the molten waste plastic mixed oil prepared in at least one of the stirring tanks,
The second circulating oil is the mixture for waste plastic decomposition treatment prepared in at least one of the line mixers,
It is preferable that the stirring tank to which at least one of the first circulating oil and the second circulating oil is supplied mixes at least one of the first circulating oil and the second circulating oil with the molten waste plastic and the raw material oil.

In one embodiment of the present invention, a method for producing a mixture for waste plastic decomposition treatment is provided.
The second preparation step prepares the mixture for waste plastic decomposition treatment using 1 to 10 of the line mixers,
When there are two or more line mixers, the two or more line mixers are preferably arranged in series, in parallel, or in a combination of series and parallel.

In one embodiment of the present invention, a method for producing a mixture for waste plastic decomposition treatment is provided.
The second preparation step includes a second circulating oil supply step of supplying a second circulating oil to at least one of the line mixers via a circulation line,
The second circulating oil is the mixture for waste plastic decomposition treatment prepared in at least one of the line mixers,
It is preferable that the line mixer to which the second circulating oil is supplied mixes the second circulating oil, the molten waste plastic mixed oil, and the raw material oil.

In one embodiment of the present invention, the method for producing a mixture for waste plastic decomposition processing preferably further includes an additional raw material supply step of supplying at least one additional raw material selected from the group consisting of the feedstock oil, light hydrocarbon oil, naphtha, diesel, and heavy hydrocarbon oil different from the feedstock oil from one or more additional raw material supply lines.

In one embodiment of the present invention, in the method for producing a mixture for waste plastic decomposition processing, the first preparation step further includes an additional feedstock supply step of supplying the additional feedstock oil to at least one of the stirring tanks, and the stirring tank to which the additional feedstock oil is supplied preferably mixes the additional feedstock oil, the molten waste plastic, and the feedstock oil.

In one embodiment of the present invention, a method for producing a mixture for waste plastic decomposition treatment is provided.
The second preparation step further includes an additional raw material supply step of supplying the additional raw material oil to at least one of the line mixers;
It is preferable that the line mixer to which the additional raw material oil is supplied mixes the additional raw material oil, the molten waste plastic mixed oil, and the raw material oil.

In one embodiment of the method for producing a mixture for waste plastic decomposition processing according to the present invention, it is preferable that the mixing in the stirring tank in the first preparation step is performed under conditions of a temperature of 175°C or higher and 260°C or lower, and a rotation speed of the first stirring means of 3 rpm or higher and 1,000 rpm or lower.

In one embodiment of the method for producing a mixture for waste plastic decomposition processing according to the present invention, it is preferable that the mixing in the line mixer in the second preparation step is performed under conditions of a temperature of 160°C or higher and 260°C or lower, and a rotation speed of the second stirring means of 10 rpm or higher and 20,000 rpm or lower.

In one embodiment of the present invention, the melting temperature of the waste plastic melted in the melting device is 175° C. or higher and 260° C. or lower,
The temperature of the raw oil in the first supply line is 80° C. or more and 240° C. or less,
The temperature of the feed oil in the second supply line is preferably 80°C or higher and 240°C or lower.

In one embodiment of the present invention, in the method for producing a mixture for waste plastic decomposition processing, the feedstock oil is preferably at least one selected from the group consisting of heavy cracked gas oil, cracked residual oil, atmospheric residual oil, desulfurized residual oil, desulfurized vacuum gas oil, undesulfurized vacuum gas oil, undesulfurized vacuum residual oil, and mineral oil.

In the method for producing a mixture for waste plastic decomposition processing according to one aspect of the present invention, the melting device is preferably a kneading machine.

In the method for producing a mixture for waste plastic decomposition processing according to one aspect of the present invention, the line mixer is preferably an in-line mixer, a line mixer, or a continuous mixer.

In the method for producing a mixture for waste plastic decomposition processing according to one aspect of the present invention, the decomposition processing device is preferably a fluid catalytic cracking device.

In the method for producing a mixture for waste plastic decomposition processing according to one aspect of the present invention, the molten waste plastic is preferably a melt of waste plastic containing at least one of polyethylene-derived waste plastic and polypropylene-derived waste plastic.

According to one aspect of the present invention, a method for producing a mixture for waste plastic decomposition processing that can improve the decomposition property of waste plastic can be provided.

FIG. 1 is a schematic diagram of an example of a processing system used to carry out the manufacturing method of the first embodiment. FIG. 11 is a schematic diagram of an example of a processing system used to carry out a manufacturing method according to a second embodiment. FIG. 13 is a schematic diagram of an example of a processing system used to carry out the manufacturing method according to the third embodiment. FIG. 13 is a schematic diagram of an example of a processing system used to carry out a manufacturing method according to a fourth embodiment. FIG. 13 is a schematic diagram of an example of a processing system used to carry out a manufacturing method according to a fifth embodiment. FIG. 13 is a schematic diagram of an example of a processing system used to carry out a manufacturing method according to a sixth embodiment.

In this specification, a numerical range expressed using "~" means a range that includes the number written before "~" as the lower limit and the number written after "~" as the upper limit.

First Embodiment
The first embodiment of the manufacturing method for a mixture for waste plastic decomposition processing (hereinafter also referred to as the manufacturing method of the first embodiment) is a manufacturing method for a mixture for waste plastic decomposition processing for decomposing waste plastic in a decomposition processing device, and has a first preparation step of preparing a molten waste plastic mixed oil by mixing molten waste plastic melted in a melting device and raw oil supplied from one or more first supply lines in a stirring tank equipped with a first stirring means, and a second preparation step of preparing a mixture for waste plastic decomposition processing by mixing the molten waste plastic mixed oil prepared in the first preparation step with raw oil supplied from one or more second supply lines in a line mixing device equipped with a second stirring means.
In the manufacturing method of the first embodiment, when the melt viscosity of the molten waste plastic is viscosity A, the melt viscosity of the molten waste plastic mixed oil prepared in the first preparation step is viscosity B, and the melt viscosity of the waste plastic decomposition mixture prepared in the second preparation step is viscosity C, the viscosity A satisfies the following formula (Mathematical formula 1), the viscosity C satisfies the following formula (Mathematical formula 2), and the viscosity ratio of the viscosity C to the viscosity B (the viscosity C/the viscosity B) is the following formula (Mathematical formula 3). The first preparation step and the second preparation step are carried out so that when the waste plastic decomposition mixture is passed through a 40 mesh filter, the passing ratio of the waste plastic decomposition mixture through the filter is 90 mass% or more.
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
5.0mPa・s<Viscosity C≦50mPa・s…(Equation 2)
Viscosity C/Viscosity B≦1/20…(Math. 3)
(In the above formulas (1) to (3), the viscosity A, the viscosity B, and the viscosity C are all melt viscosities (mPa·s) at 200° C.)

The inventors have discovered that by gradually mixing molten waste plastic and raw oil so as to satisfy the viscosity A of formula (1), the viscosity C of formula (2), and the viscosity ratio (the viscosity C/the viscosity B) of formula (3), it is possible to increase the filter passing rate of the mixture for waste plastic decomposition processing (hereinafter also referred to as the passing rate of the 40 mesh filter) to 90 mass% or more when the mixture for waste plastic decomposition processing is passed through a 40 mesh filter.
A passing rate through the 40 mesh filter of 90% by mass or more indicates that the mixture for waste plastic decomposition processing is uniformly mixed in the feedstock oil.
Therefore, according to the manufacturing method of the first embodiment, the mixability of the molten waste plastics and the raw oil is improved, and a mixture for waste plastic decomposition processing is obtained that can improve the decomposition ability of the waste plastics.

The manufacturing method of the first embodiment can be carried out by using, for example, the processing system shown in FIG.
First, the processing system 100 shown in Fig. 1 will be described, and then the manufacturing method of the first embodiment will be described. In the following description, ordinal expressions such as "first", "second" and "third" are intended to distinguish between components and do not indicate order. In the following description, the waste plastic decomposition mixture may be simply referred to as the decomposition mixture.

<Overall composition>
The processing system 100 shown in Fig. 1 includes a kneader 20 (an example of a melting device), a first storage tank 60 (an example of a stirring tank), a line mixer 30 (an example of a line mixing device), a second storage tank 40, a residual oil fluid catalytic cracking unit (RFCC unit 50) (an example of a cracking processing unit), a first transport line 10, a mixed oil transport line 15, a supply line 11A (an example of a first supply line), a supply line 13 (an example of a second supply line), and a second transport line 14. The processing system 100 also includes a waste plastic supply control means 25, a first raw oil supply control means 111, and a third raw oil supply control means 131.

(Kneader 20)
The kneader 20 prepares molten waste plastics by melting the waste plastics.
Molten waste plastic refers to solid waste plastic that has been melted and turned into liquid. Therefore, the only difference between molten waste plastic and solid waste plastic is the state of the material.
The molten waste plastic is a melted product of waste plastic. The waste plastic is melted in the kneader 20 to become molten waste plastic, and is in a molten state, a dissolved state, or a slurry.

A waste plastic supply control means 25 for controlling the supply amount of waste plastic is connected to the kneader 20 .
The waste plastic supply control means 25 has a feeder 21 as a waste plastic supply means, and a feeder controller 24 that controls the operation of the feeder 21. The waste plastic supply control means 25 controls the amount of waste plastic supplied 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. In this specification, the amount of waste plastic supplied means the amount (mass) of waste plastic supplied per unit time.
Further, the kneader 20 is connected to a feeder 21 and a hopper 22 via a waste plastic supply line 23. The hopper 22 has a supply port (not shown) at a lower portion, and is capable of supplying waste plastic to the feeder 21 from the supply port.
The kneader 20 melts the waste plastics supplied from the hopper 22 via the feeder 21 to prepare molten waste plastics.

The waste plastic supply control means 25 may control the melting amount of the molten waste plastic by controlling the supply amount of the waste plastic from the feeder 21 to the kneader 20. In this specification, the melting amount of the molten waste plastic means the amount (mass) of the waste plastic melted per unit time. The melting amount of the molten waste plastic is calculated from the supply amount of the waste plastic.
The kneading machine 20 is not particularly limited, but examples thereof include an extruder (for example, a single-screw extruder or a multi-screw extruder), a kneader, and a mixer.

(First transport line 10)
The first transportation line 10 is connected to the RFCC unit 50 and transports the feed oil to the RFCC unit 50. The first transportation line 10 has, in order from the upstream side, a branch point B11 branching off to a supply line 11A, a branch point B1 branching off to a supply line 13, and a junction C1 with the second transportation line 14.
The temperature of the raw 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, for example, by a temperature control means (e.g., a heat exchanger, a heater, etc.) installed at any location in the first transport line 10.

(Supply line 11A)
The supply line 11A, which serves as a first supply line, connects the first transport line 10 to the kneader 20 and supplies the raw oil from the first transport line 10 to the kneader 20 .
In the case of Fig. 1, the supply line 11A branches off from the branch point B11 of the first transport line 10, and supplies the raw oil to the outlet side of the kneader 20. A heat exchanger HE for controlling the temperature of the raw oil in the supply line 11A and a first raw oil supply control means 111 for controlling the amount of the raw oil supplied to the kneader 20 are provided midway along the supply line 11A.
The first feedstock oil supply control means 111 has a first adjustment valve 112 as a feedstock oil supply means, and a first controller 113 .
The first feedstock oil supply control means 111 controls the amount of feedstock oil supplied by transmitting a control signal from the first controller 113 to the first adjustment valve 112 and controlling the operation of the first adjustment valve 112. A microcomputer or the like can be used as the first controller 113. In this specification, the amount of feedstock oil supplied means the amount (mass) supplied per unit time.
The temperature of the feed oil in the supply line 11A will be described later.

(Mixed oil transport line 15)
The mixed oil transport line 15 connects the kneader 20, the first storage tank 60, and the line mixer 30 to each other.
In the case of Fig. 1, the molten waste plastics melted in the kneader 20 and the raw oil supplied from the supply line 11A become a mixed oil of the molten waste plastics and the raw oil, which is transported through the mixed oil transport line 15 and supplied to the first storage tank 60. The temperature of the mixed oil in the mixed oil transport line 15 is preferably 160°C or higher and 260°C or lower, and can be controlled, for example, by a temperature control means (for example, a heat exchanger, a heater, etc.) installed at any position on the mixed oil transport line 15.

(First storage tank 60)
The first storage tank 60 includes a rotor 80 serving as a first stirring means. The rotor 80 is connected to a motor (not shown).
The first storage tank 60 prepares a molten waste plastic mixed oil by mixing the mixed oil (mixed oil of molten waste plastic and raw material oil) supplied from the mixed oil transport line 15 with a rotor 80. Examples of the first stirring means include stirring blades such as impellers and rotors. Examples of the stirring blades include screw type, propeller type, paddle type, and turbine type, but the shape of the stirring blade is not particularly limited.
A gear pump 61 is connected to the first storage tank 60. The first storage tank 60 is preferably equipped with a pump such as the gear pump 61 as a means for supplying the molten waste plastic mixed oil to the line mixer 30, but the molten waste plastic mixed oil may be supplied to the line mixer 30 via the mixed oil transport line 15 by its own pressure.
The first storage tank 60 preferably has a degassing means for discharging gas (e.g., carbon dioxide gas, water vapor, volatile organic compounds, etc.) generated from the molten waste plastic mixed oil. The degassing means is not particularly limited, but may be, for example, a degassing pipe.

(Supply line 13)
The supply line 13 serving as a second supply line connects the first transport line 10 and the line mixer 30 and supplies the raw oil from the first transport line 10 to the line mixer 30 .
In the case of FIG. 1 , the supply line 13 branches off from a branch point B<b>1 of the first transportation line 10 and supplies the raw material oil to a line mixer 30 .
A heat exchanger HE for controlling the temperature of the raw oil in the supply line 13 and a third raw oil supply control means 131 for controlling the amount of the raw oil supplied are provided in the supply line 13 .
The third feedstock oil supply control means 131 has a third adjustment valve 132 as a feedstock oil supply means, and a third controller 133. The third feedstock oil supply control means 131 controls the amount of feedstock oil supplied by transmitting a control signal from the third controller 133 to the third adjustment valve 132 and controlling the operation of the third adjustment valve 132. The third adjustment valve 132 can use a microcomputer or the like.
The temperature of the feed oil in the supply line 13 will be described later.

(Line mixer 30)
The line mixer 30 includes a stirring blade 90 as a second stirring means. The stirring blade 90 is connected to a motor (not shown).
The line mixer 30 prepares a mixture for decomposition treatment by mixing the molten waste plastic mixed oil prepared in the first storage tank 60 and the raw material oil supplied from the supply line 13 with the stirring blade 90. Examples of the second stirring means include stirring blades such as impellers and rotors. Examples of the stirring blades include screw type, propeller type, paddle type, and turbine type, but the shape is not particularly limited. An element may also be used as the second stirring means.
The line mixer 30 is not particularly limited, and an in-line mixer (for example, a static mixer) may be used. The line mixer 30 may be a continuous mixer.

(Second storage tank 40)
The second storage tank 40 stores the decomposition treatment mixture prepared in the line mixer 30. A centrifugal pump 41 is connected to the second storage tank 40. The pump connected to the second storage tank 40 is not particularly limited, and a gear pump, for example, may be used. The second storage tank 40 is preferably equipped with a pump as a means for supplying the decomposition treatment mixture, but the decomposition treatment mixture may be supplied to the second transport line 14 by its own pressure.
The second storage tank 40 preferably has a venting means for discharging gases (e.g., carbon dioxide gas, water vapor, volatile organic compounds, etc.) generated from the decomposition treatment mixture. The venting means is not particularly limited, but may be, for example, a venting pipe.
In addition, the second storage tank 40 may have a stirring means (e.g., a rotor or the like) from the viewpoint of further improving the mixability of the decomposition treatment mixture.
The temperature of the second storage tank 40 is preferably 160° C. or higher and 240° C. or lower. The second storage tank 40 is preferably equipped with a temperature detection means (e.g., a thermometer, etc.), and the temperature of the second storage tank 40 is preferably controlled by a temperature control means (e.g., a heat exchanger, a heater, etc.).

(Second transport line 14)
The second transport line 14 transports the decomposition treatment mixture prepared in the line mixer 30 from the line mixer 30 to the first transport line 10 using a centrifugal pump 41.
In the case of FIG. 1, the second transport line 14 transports the decomposition treatment mixture to the second storage tank 40, and then transports it to the junction C1 with the first transport line 10 by the centrifugal pump 41.
The temperature of the mixture for decomposition treatment in the second transport line 14 is preferably 160°C or higher and 240°C or lower, and can be controlled, for example, by a temperature control means (e.g., a heat exchanger, a heater, etc.) installed at any location in the second transport line 14.

(RFCC device 50)
The RFCC device 50 decomposes the molten waste plastics in the mixture for decomposition treatment prepared in the line mixer 30 into liquefied petroleum gases (propane, propylene, n-butane, isobutane, butylene, etc.), and decomposes the raw oil into FG (gasoline), LCO (light cracked diesel oil), CLO (residual oil), etc.
In the case of FIG. 1, the mixture for cracking treatment transported via the second transport line 14 is joined at a joining point C1 with the feed oil transported via the first transport line 10 and supplied to the RFCC unit 50.
The RFCC unit 50 is one embodiment of a fluid catalytic cracking unit (FCC unit).
The RFCC unit 50 and the FCC unit may be units commonly used in the field of petroleum refining, and basically consist of a reaction tower, a catalyst/product oil separator, a section for removing oil from the catalyst surface, and a catalyst regeneration tower, with the catalyst circulating within this system.
The catalyst used is usually a catalyst containing synthetic zeolite, and the process may be any process developed by UOP, IFP, or the like.
The catalysts and operating conditions used in the RFCC unit 50 and the FCC unit are not particularly limited and can be set appropriately.

[Manufacturing method of the first embodiment]
When the processing system 100 shown in FIG. 1 is used, the manufacturing method of the first embodiment is carried out through the following steps.

<First preparation step>
The first preparation process prepares molten waste plastic mixed oil by mixing molten waste plastic melted in the kneader 20 with raw oil supplied from the supply line 11A in a first storage tank 60 equipped with a rotor 80.

(Melt viscosity of molten waste plastic (viscosity A))
The melt viscosity (viscosity A) of the molten waste plastic melted in the kneader 20 satisfies the following formula (Mathematical formula 1). It is preferable that the viscosity A satisfies the following formula (Mathematical formula 1A).
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
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 plastics can be melted without applying an excessive load in the kneader 20, making it easier to control the melting amount of the molten waste plastics.
When the melt viscosity (viscosity A) is 1.0×10 ⁸ mPa·s or less, the waste plastic can be melted by the frictional heat between the molten resins in addition to a certain degree of load on the kneader 20 .
Therefore, when the melt viscosity (viscosity A) satisfies the above formula (Formula 1), it becomes easier to prepare a mixture for use in the decomposition treatment of waste plastics that has sufficient mixability.

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

The raw oil in the supply line 11A is preferably heated to a temperature at which the raw oil and the molten waste plastics can be mixed while maintaining the molten state of the molten waste plastics.
The temperature of the raw oil in the supply line 11A is preferably 80°C or higher and 240°C or lower, and more preferably 80°C or higher and 240°C or lower.

In the first preparation step, from the viewpoint of making it easier to adjust the viscosity ratio (the viscosity C/the viscosity B) in the formula (3), the mixing in the first storage tank 60 is preferably performed under conditions of a temperature (mixing temperature) of 175°C or higher and 260°C or lower and a rotation speed of the rotor 80 of 3 rpm or higher and 1,000 rpm or lower, and more preferably under conditions of a temperature of 200°C or higher and 240°C or lower and a rotation speed of the rotor 80 of 10 rpm or higher and 500 rpm or lower.
The mixing temperature is a set temperature of the first storage tank 60. It is preferable that the first storage tank 60 includes a temperature detection means (e.g., a thermometer, etc.), and the mixing temperature is controlled by a temperature control means (e.g., a heat exchanger, a heater, etc.).

(Melt viscosity of molten waste plastic mixed oil (viscosity B))
The melt viscosity (viscosity B) of the molten waste plastic mixed oil prepared in the first preparation step preferably satisfies the following formula (Mathematical Formula 5A), and more preferably satisfies the following formula (Mathematical Formula 5B).
The melt viscosity of the molten waste plastic mixed oil (viscosity B) is the melt viscosity of the molten waste plastic mixed oil near the outlet of the stirring tank. In the case of Figure 1, it is the melt viscosity of the molten waste plastic mixed oil in the mixed oil transport line 15 connected to the outlet of the first storage tank 60.
1000mPa・s≦Viscosity B≦1 million mPa・s…(Several 5A)
1000mPa・s≦Viscosity B≦500,000mPa・s…(Several 5B)
(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 formula (Formula 5A), it becomes easier to adjust the viscosity ratio (the viscosity C/the viscosity B) of the formula (Formula 3) in the second preparation step. In addition, the transportability of the molten waste plastic mixed oil is improved.

<Second preparation step>
In the second preparation step, the molten waste plastic mixed oil prepared in the first preparation step and the raw material oil supplied from the supply line 13 are mixed in a line mixer 30 equipped with an agitating blade 90 to prepare a mixture for waste plastic decomposition processing. The second preparation step is carried out so as to satisfy the viscosity C in the formula (Math. 2) and the viscosity ratio (the viscosity C/the viscosity B) in the formula (Math. 3). In addition, when the mixture for waste plastic decomposition processing prepared in the second preparation step is passed through a 40 mesh filter, the passing rate of the filter is 90 mass% or more.

It is preferable that the raw material oil in the supply line 13 is heated to a temperature at which the molten mixed oil of waste plastics can be mixed with the raw material oil in the line mixer 30 while maintaining the molten state of the molten mixed oil of waste plastics.
The temperature of the raw oil in the supply line 13 is preferably 80°C or higher and 240°C or lower, and more preferably 80°C or higher and 240°C or lower.

In the second preparation step, from the viewpoint of facilitating adjustment of the viscosity C in the formula (Mathematical Expression 2) and the viscosity ratio (the viscosity C/the viscosity B) in the formula (Mathematical Expression 3), the mixing in the line mixer 30 is preferably performed under conditions of a temperature (mixing temperature) of 160° C. or higher and 260° C. or lower and a rotation speed of the stirring blade 90 of 10 rpm or higher and 20,000 rpm or lower, and more preferably under conditions of a temperature of 170° C. or higher and 240° C. or lower and a rotation speed of the stirring blade 90 of 100 rpm or higher and 10,000 rpm or lower.
The mixing temperature is a set temperature of the line mixer 30. The line mixer 30 is preferably equipped with a temperature detection means (e.g., a thermometer, etc.), and the mixing temperature is preferably controlled by a temperature control means (e.g., a heat exchanger, a heater, etc.).

(Melt viscosity of mixture for waste plastic decomposition processing (viscosity C))
The melt viscosity (viscosity C) of the decomposition treatment mixture prepared in the second preparation step satisfies the following formula (Mathematical formula 2): It is preferable that the viscosity C satisfies the following formula (Mathematical formula 2A).
The melt viscosity of the mixture for cracking treatment (viscosity C) is the melt viscosity of the mixture for cracking treatment near the outlet of the line mixer. In the case of FIG. 1, it is the melt viscosity of the mixture for cracking treatment in the second transport line 14 connected to the outlet of the line mixer 30.
5.0mPa・s<Viscosity C≦50mPa・s…(Equation 2)
5.0mPa・s<Viscosity C≦30mPa・s…(Math 2A)
(Viscosity C is the melt viscosity (mPa·s) at 200° C.)

When the melt viscosity (viscosity C) of the decomposition treatment mixture exceeds 5.0 mPa·s, localized areas of high viscosity are unlikely to occur, resulting in good mixability.
If the melt viscosity (viscosity C) of the mixture for decomposition treatment is 50 mPa·s or less, the molten waste plastic and the raw material oil are difficult to separate, so that the viscosity tends to be close to uniform, resulting in good mixability.
Therefore, when the melt viscosity (viscosity C) of the mixture for decomposition treatment satisfies the above formula (Mathematical formula 2), the mixture for decomposition treatment of waste plastics is likely to have sufficient mixability.

The second preparation step is carried out so that the viscosity ratio of the viscosity C to the viscosity B (the viscosity C/the viscosity B) satisfies the mathematical formula (Mathematical Formula 3). The viscosity ratio (the viscosity C/the viscosity B) preferably satisfies the following mathematical formula (Mathematical Formula 3A), and more preferably satisfies the following mathematical formula (Mathematical Formula 3B).
Viscosity C/Viscosity B≦1/20…(Math. 3)
Viscosity C/Viscosity B≦1/2,000…(Math 3A)
Viscosity C/Viscosity B≦1/200,000…(Math. 3B)
(Viscosity B and viscosity C are melt viscosities (mPa·s) at 200° C.)

When the viscosity ratio (said viscosity C/said viscosity B) satisfies the above formula (Formula 3), the mixture for waste plastic decomposition processing tends to be in a state of sufficient mixability.

(Method of measuring melt viscosity (viscosity A, viscosity B and viscosity C))
The melt viscosity of the molten waste plastic at 200°C (viscosity A), the melt viscosity of the molten waste plastic mixed oil (viscosity B), and the melt viscosity of the decomposition treatment mixture (viscosity C) were measured using a rheometer device (Anton Paar, MCR302 (product number)) under the following conditions using a cone plate as the measuring tool.
<Conditions>
- Cone-plate measuring system: DIN EN (compliant with ISO 3219 and DIN 53019)
・Angular frequency (ω): 0.1 rad/sec to 100 rad/sec ・Measurement temperature: 200℃
・Sample weight: 0.1g to 0.3g

(Percentage of decomposition mixture passing through 40 mesh filter)
When the mixture for decomposition treatment prepared in the second preparation step is passed through a 40 mesh filter, the passing rate of the mixture for decomposition treatment through the 40 mesh filter is 90 mass% or more. The higher the passing rate through the 40 mesh filter, the more preferable.
The passing rate of the 40 mesh filter is measured using the mixture for decomposition treatment near the outlet of the line mixer. In the case of FIG. 1, it is measured using the mixture for decomposition treatment in the second transport line 14 connected to the outlet of the line mixer 30.
The method for measuring the passing rate through a 40 mesh filter will be described in the Examples section.

<Decomposition treatment mixture storage step>
The manufacturing method of the first embodiment includes a decomposition treatment mixture storage step of storing the waste plastic decomposition treatment mixture prepared in the second preparation step in the second storage tank 40.

＜Effects＞
In the manufacturing method of the first embodiment, the first preparation step and the second preparation step are carried out using the kneader 20, the first storage tank 60, and the line mixer 30 so as to satisfy the viscosity A of the formula (1), the viscosity C of the formula (2), and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3), thereby making it possible to increase the passing rate of the mixture for waste plastic decomposition processing through the filter to 90 mass% or more. Thus, a mixture for decomposition processing having improved mixability between the molten waste plastic and the raw oil and improved decomposability of the waste plastic can be obtained.
In addition, since the melt viscosity (viscosity C) of the decomposition treatment mixture obtained by the manufacturing method of the first embodiment is adjusted, the load on the transportation means (e.g., centrifugal pump 41, etc.) when transporting it to the RFCC device 50 can be reduced.

Second Embodiment
The second embodiment will be described focusing on the differences from the first embodiment, and the description of similar items will be omitted or simplified by using the same reference numerals, for example.
The manufacturing method according to the second embodiment is an example carried out using a processing system shown in Fig. 2. First, the processing system 200 shown in Fig. 2 will be described, and then the manufacturing method according to the second embodiment will be described.

<Overall composition>
The processing system 200 shown in FIG. 2 is similar to the processing system 100 described in the first embodiment, except that the processing system 200 includes a supply line 12 (an example of a first supply line) instead of the supply line 11A.

<Supply line 12>
The supply line 12 as the first supply line branches off from the branch point B1 of the first transportation line 10, and further branches off at a branch point B3 to supply the raw oil to a junction C3 with the mixed oil transportation line 15. A heat exchanger HE for controlling the temperature of the raw oil in the supply line 12 and a second raw oil supply control means 121 for controlling the supply amount of the raw oil are provided midway along the supply line 12.
The second feedstock oil supply control means 121 controls the amount of feedstock oil supplied by transmitting a control signal from the second controller 123 to the second control valve 122 and controlling the operation of the second control valve 122. The second controller 123 can be a microcomputer or the like.
The temperature of the feed oil in the supply line 12 will be described later.

[Manufacturing method of the second embodiment]
The production method of the second embodiment is similar to that of the first embodiment, except that the first preparation step is carried out in the following manner. The production method of the second embodiment will be described, focusing on the differences from the first embodiment.

<First preparation step>
The first preparation step of the second embodiment prepares molten waste plastic mixed oil by mixing the molten waste plastic prepared in the kneader 20 with raw oil supplied from the supply line 12 in a first storage tank 60 equipped with a rotor 80.

The temperature of the raw oil in the supply line 12 is preferably 80°C or higher and 240°C or lower, and more preferably 80°C or higher and 240°C or lower.

It is preferable that the mixing conditions in the first storage tank 60 (mixing temperature and rotation speed of the rotor 80) and the melt viscosity (viscosity B) of the molten waste plastic mixed oil prepared in the first storage tank 60 are in the same range as in the first embodiment.

＜Effects＞
According to the manufacturing method of the second embodiment, the first preparation step and the second preparation step are carried out using the kneader 20, the first storage tank 60 to which the raw oil is supplied from the supply line 12, and the line mixer 30 to which the raw oil is supplied from the supply line 13, so as to satisfy the viscosity A of the formula (1), the viscosity C of the formula (2), and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3), thereby making it possible to increase the passing rate of the mixture for waste plastic decomposition processing through the filter to 90 mass% or more. As a result, a mixture for decomposition processing having improved mixability between the molten waste plastic and the raw oil and improved decomposability of the waste plastic can be obtained.

Third Embodiment
The third embodiment will be described focusing on the differences from the first and second embodiments, and the description of similar items will be omitted or simplified by using the same reference numerals, etc. The manufacturing method of the third embodiment is an example carried out using the processing system shown in Fig. 3. First, the processing system 300 shown in Fig. 3 will be described, and then the manufacturing method of the third embodiment will be described.

<Overall composition>
3 differs from the processing system 200 described in the second embodiment in that the processing system 300 includes a supply line 11 (an example of a first supply line), the first storage tank 60 includes a degassing line 44, and the second storage tank 40 includes a degassing line 43. The other points are the same as those of the second embodiment.
The processing system 300 includes two supply lines (supply line 11 and supply line 12) as the first supply line.

<Supply line 11>
A supply line 11 as a first supply line branches off from a branch point B1 of the first transport line 10, and further branches off at a branch point B2 to supply raw material oil to the outlet side of the kneader 20. A first raw material oil supply control means 111 similar to that of the first embodiment is provided in the middle of the supply line 11.

[Manufacturing method of the third embodiment]
The manufacturing method of the third embodiment is the same as that of the second embodiment, except that the first preparation step and the decomposition treatment mixture storage step are carried out in the following manner. The manufacturing method of the third embodiment will be described, focusing on the differences from the second embodiment.

<First preparation step>
The first preparation step of the third embodiment prepares molten waste plastic mixed oil by mixing molten waste plastic prepared in the kneader 20, raw oil supplied to the outlet side of the kneader 20 from the supply line 11, and raw oil supplied from the supply line 12 in a first storage tank 60 equipped with a rotor 80.

The temperature of the raw oil in the supply line 11 is preferably 80°C or higher and 240°C or lower, and more preferably 80°C or higher and 240°C or lower.
The temperature of the feed oil in the supply line 11 is preferably controlled in a manner similar to that of the feed oil in the supply line 11A of the first embodiment.

It is preferable that the mixing conditions in the first storage tank 60 (mixing temperature and rotation speed of the rotor 80) and the melt viscosity (viscosity B) of the molten waste plastic mixed oil prepared in the first storage tank 60 are in the same range as in the first embodiment.

(First gas release step)
The first preparation step of the third embodiment includes a first degassing step, which is a step of discharging gas (e.g., carbon dioxide gas, water vapor, and volatile organic compounds) generated from the molten waste plastic mixed oil from the first storage tank 60 through a degassing line 44 (an example of a degassing means).

<Decomposition treatment mixture storage step>
(Second gas release process)
The decomposition mixture storage step of the third embodiment includes a second degassing step in which gases (e.g., carbon dioxide gas, water vapor, and volatile organic compounds) generated from the decomposition mixture are discharged from the second storage tank 40 via a degassing line 43 (an example of a degassing means).

＜Effects＞
According to the manufacturing method of the third embodiment, the percentage of the mixture for decomposition processing that passes through the filter can be increased to 90 mass% or more, thereby obtaining a mixture for waste plastic decomposition processing that has improved mixability between molten waste plastic and raw oil, and improved decomposition ability of waste plastic.
In addition, according to the manufacturing method of the third embodiment, the raw material oil can be supplied to the kneader 20 and the first storage tank 60, respectively, so that the viscosity ratio (the viscosity C/the viscosity B) can be easily adjusted. As a result, a mixture for decomposition treatment is obtained that has improved mixability between the molten waste plastic and the raw material oil and improved decomposition ability of the waste plastic.
In addition, the manufacturing method of the third embodiment has a first degassing process, which can prevent or reduce foaming of the molten waste plastic mixed oil, and can smoothly transfer the molten waste plastic mixed oil to the line mixer 30. Similarly, the manufacturing method of the third embodiment has a second degassing process, which can prevent or reduce foaming of the decomposition treatment mixture, and can smoothly transfer the decomposition treatment mixture to the decomposition treatment device. Therefore, according to the manufacturing method of the third embodiment, improved operability is expected.

Fourth Embodiment
The fourth embodiment will be described focusing on the differences from the first to third embodiments, and the description of similar matters will be omitted or simplified by using the same reference numerals, for example.
The manufacturing method according to the fourth embodiment is an example carried out using a processing system shown in Fig. 4. First, the processing system 400 shown in Fig. 4 will be described, and then the manufacturing method according to the fourth embodiment will be described.

<Overall composition>
4 differs from the processing system 300 described in the third embodiment in that the processing system 400 includes two line mixers. The other points are the same as those of the third embodiment.

<Line mixers 30, 30B>
The two line mixers 30 and 30B are arranged in parallel, and each of them is provided with a stirring blade 90 as a second stirring means. The line mixer 30B may have the same configuration as the line mixer 30, or may have a different configuration from the line mixer 30.

<Mixed oil transport line 15>
The mixed oil transport line 15 of the fourth embodiment connects the kneader 20, the first storage tank 60, the line mixer 30, and the line mixer 30B.
In the case of Fig. 4, the mixed oil transport line 15 branches into a first mixed oil transport line 151 and a second mixed oil transport line 152 at a branch point B5 downstream of the first storage tank 60. The first mixed oil transport line 151 is connected to the line mixer 30. The second mixed oil transport line 152 is connected to the line mixer 30B.

<Supply line 13>
The supply line 13 of the fourth embodiment connects the first transport line 10, the line mixer 30 and the line mixer 30B.
In the case of Fig. 4, the supply line 13 branches from the branch point B1 of the first transportation line 10 through branch points B2 and B3, and then branches into a first feed oil supply line 13A and a second feed oil supply line 13B at a branch point B4. The first feed oil supply line 13A is connected to a line mixer 30. The second feed oil supply line 13B is connected to a line mixer 30B.
A third feedstock supply control means 131 similar to that in the third embodiment is provided in the first feedstock supply line 13A.
A fourth feedstock supply control means for controlling the amount of feedstock supplied to the line mixer 30B is also provided in the second feedstock supply line 13B, but the fourth feedstock supply control means is not shown. The fourth feedstock supply control means may have the same configuration and operating conditions as the third feedstock supply control means 131, or may have different configurations and operating conditions.

[Manufacturing method of the fourth embodiment]
The production method of the fourth embodiment is the same as that of the third embodiment, except that the second preparation step is carried out in the following manner. The production method of the fourth embodiment will be described, focusing on the differences from the third embodiment.

<Second preparation step>
In the second preparation step of the fourth embodiment, a mixture for decomposition treatment is prepared using two line mixers 30, 30B arranged in parallel.
The line mixer 30 prepares a mixture for cracking treatment (hereinafter also referred to as "mixture for cracking treatment X1") by mixing the molten waste plastic mixed oil with the raw oil supplied from the first raw oil supply line 13A so as to satisfy the viscosity C of the formula (2) and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3). Similarly, the line mixer 30B prepares a mixture for cracking treatment (hereinafter also referred to as "mixture for cracking treatment Y1") by mixing the molten waste plastic mixed oil with the raw oil supplied from the second raw oil supply line 13B so as to satisfy the viscosity C of the formula (2) and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3).

The mixing conditions of the line mixers 30 and 30B (mixing temperature and rotation speed of the stirring blade 90) are preferably in the same range as in the first embodiment. The mixing conditions of the line mixers 30 and 30B may be the same or different from each other.

<Decomposition treatment mixture storage step>
In the case of FIG. 4, the mixture for decomposition treatment X1 and the mixture for decomposition treatment Y1 join at the joining point C4 of the second transport line 14 and are then stored in the second storage tank 40.

＜Effects＞
In the manufacturing method of the fourth embodiment, the first preparation step and the second preparation step are carried out using a kneader 20, a first storage tank 60, and two line mixers 30, 30B so as to satisfy the viscosity A of the formula (1), the viscosity C of the formula (2), and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3), thereby increasing the passing rate of the decomposition treatment mixture through the filter to 90% by mass or more. In the case of FIG. 4, the passing rates of the decomposition treatment mixture X1 and the decomposition treatment mixture Y1 through the filter are both 90% by mass or more. As a result, a decomposition treatment mixture having improved mixability between the molten waste plastic and the raw material oil and improved decomposability of the waste plastic is obtained.
In addition, in the manufacturing method of the fourth embodiment, the mixture for decomposition processing is prepared using two line mixers 30, 30B, which further improves the mixing state of the molten waste plastics and the raw oil and makes it possible to prepare a larger amount of the mixture for decomposition processing to be decomposed.
Therefore, according to the manufacturing method of the fourth embodiment, the amount of waste plastic decomposed can be increased.

Fifth Embodiment
The fifth embodiment will be described focusing on the differences from the first to fourth embodiments, and the description of similar items will be omitted or simplified by using the same reference numerals, for example.
The manufacturing method according to the fifth embodiment is an example carried out using a processing system shown in Fig. 5. First, the processing system 500 shown in Fig. 5 will be described, and then the manufacturing method according to the fifth embodiment will be described.

<Overall composition>
The processing system 500 shown in Fig. 5 differs from the processing system 400 described in the fourth embodiment in that it includes two kneaders and four line mixers, includes an additional raw material oil supply line 70, and does not include the supply line 12. The other points are the same as those of the fourth embodiment.

<Kneader 20, 20A>
The processing system 500 of the fifth embodiment includes two kneaders 20 and 20A arranged in parallel.

<Line mixers 30, 30A, 30B, 30C>
In the treatment system 500 of the fifth embodiment, compared to the fourth embodiment, a line mixer 30A is arranged between the line mixer 30 and the second storage tank 40, and a line mixer 30C is arranged between the line mixer 30B and the second storage tank 40.

<Additional Feedstock Oil Supply Line 70>
The additional feedstock supply line 70 supplies another additional feedstock (hereinafter also referred to as additional feedstock) to the outlet side of the kneader 20A. An additional feedstock supply control means 171 for controlling the supply amount of the additional feedstock is provided in the additional feedstock supply line 70. The additional feedstock supply control means 171 has a fourth adjustment valve 172 as additional feedstock supply means and a fourth controller 173.
The additional raw material supply control means 171 transmits a control signal from the fourth controller 173 to the fourth adjustment valve 172 and controls the operation of the fourth adjustment valve 172, thereby controlling the amount of additional raw material oil supplied.
The temperature of the additional feedstock oil in the additional feedstock oil supply line 70 is preferably 80°C or more and 240°C or less, more preferably 160°C or more and 230°C or less, from the viewpoint of maintaining the molten state of the molten waste plastic and mixing the molten waste plastic and the additional feedstock oil well, and can be controlled, for example, by a temperature control means (e.g., a heat exchanger, a heater, etc.) installed at any position in the additional feedstock oil supply line 70. The temperature of the additional feedstock oil in the additional feedstock oil supply line 70 is the set temperature of the temperature control means.
The additional feedstock supply line 70 may be connected to an additional feedstock storage tank for storing the additional feedstock. In addition, the additional feedstock supply line 70 may be, for example, the supply line 11 or the supply line 13 connected to the first transport line 10, and may be used as the additional feedstock supply line 70 so that the additional feedstock can be supplied from the first transport line 10 to the kneader 20.
The number of additional feedstock oil supply lines 70 is not limited, and may be one or two or more.

<Mixed oil transport line 15>
The mixed oil transport line 15 connects the kneader 20, the kneader 20A, the first storage tank 60, the line mixer 30, and the line mixer 30B.

[Manufacturing method of the fifth embodiment]
The manufacturing method of the fifth embodiment is the same as that of the fourth embodiment, except that the first preparation step and the second preparation step are carried out in the following manner. Hereinafter, the manufacturing method of the fifth embodiment will be described, focusing on the differences from the fourth embodiment.

<First preparation step>
The first preparation process of the fifth embodiment further includes an additional raw material supply process, in which molten waste plastics melted in two kneaders 20, 20A, raw material oil, and additional raw material oil are mixed in a first storage tank 60 to prepare a molten waste plastic mixed oil.
Specifically, the molten waste plastics melted in the kneader 20 are transported together with the raw material oil supplied from the supply line 11 through the mixed oil transport line 15 and supplied to the first storage tank 60. The molten waste plastics melted in the kneader 20A are transported together with the additional raw material oil supplied from the additional raw material oil supply line 70 through the mixed oil transport line 15 and supplied to the first storage tank 60. The molten waste plastics, raw material oil and additional raw material oil supplied to the first storage tank 60 are mixed by the rotor 80 to prepare a molten waste plastic mixed oil.
The molten waste plastic mixed oil prepared in the first storage tank 60 is transported through the mixed oil transport line 15 by the gear pump 61, and a portion of it is supplied to the line mixer 30 via the first mixed oil transport line 151 from the branch point B5, and the remainder is supplied to the line mixer 30B via the second mixed oil transport line 152 from the branch point B5.

The melt viscosity (viscosity A) of the molten waste plastics melted in the kneaders 20 and 20A respectively satisfies the above formula (Formula 1).
The mixer 20A may have the same configuration and operating conditions as the mixer 20, or may have a different configuration and operating conditions.
It is preferable that the mixing conditions in the first storage tank 60 (mixing temperature and rotation speed of the rotor 80) and the melt viscosity (viscosity B) of the molten waste plastic mixed oil prepared in the first storage tank 60 are in the same range as in the first embodiment.

<Second preparation step>
In the second preparation step of the fifth embodiment, a mixture for decomposition treatment is prepared using four line mixers shown in FIG.
The line mixer 30 prepares a cracking treatment mixture by mixing the molten waste plastic mixed oil supplied from the first mixed oil transport line 151 and the raw oil supplied from the first raw oil supply line 13A. The cracking treatment mixture is then supplied to the line mixer 30A. The line mixer 30A further mixes the cracking treatment mixture to adjust the cracking treatment mixture (hereinafter also referred to as "cracking treatment mixture X2") so as to satisfy the viscosity C of the formula (2) and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3). Similarly, the line mixer 30B prepares a cracking treatment mixture by mixing the molten waste plastic mixed oil supplied from the second mixed oil transport line 152 and the raw oil supplied from the second raw oil supply line 13B. The cracking treatment mixture is then supplied to the line mixer 30C. The line mixer 30C further mixes the mixture for decomposition treatment so as to satisfy the viscosity C of the formula (Equation 2) and the viscosity ratio (the viscosity C/the viscosity B) of the formula (Equation 3) to prepare a mixture for decomposition treatment (hereinafter also referred to as "mixture for decomposition treatment Y2").

The mixing conditions (mixing temperature and rotation speed of the stirring blade 90) in the line mixers 30, 30A, 30B, and 30C are preferably in the same range as in the first embodiment. The mixing conditions in the line mixers 30, 30A, 30B, and 30C may be the same or different from each other.

<Decomposition treatment mixture storage step>
In the case of FIG. 5, the mixture for decomposition treatment X2 and the mixture for decomposition treatment Y2 join at the joining point C4 of the second transport line 14 and are then stored in the second storage tank 40.

＜Effects＞
In the manufacturing method of the fifth embodiment, two kneaders 20, 20A, a first storage tank 60, and four line mixers 30, 30A, 30B, 30C are used to perform the first preparation step and the second preparation step so as to satisfy the viscosity A of the formula (1), the viscosity C of the formula (2), and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3), thereby increasing the passing rate of the decomposition treatment mixture through the filter to 90% by mass or more. In the case of FIG. 5, the passing rates of the decomposition treatment mixture X2 and the decomposition treatment mixture Y2 through the filter are both 90% by mass or more. As a result, a decomposition treatment mixture having improved mixability between the molten waste plastic and the raw material oil and improved decomposability of the waste plastic is obtained.
In addition, in the manufacturing method of the fifth embodiment, the two kneaders 20, 20A can be set to the same or different operating conditions depending on the type, composition, shape, and state of the waste plastic to be treated, and the type of additional raw oil to be supplied to the kneader 20A can be appropriately selected, so that it is easy to obtain a molten waste plastic mixed oil that satisfies the viscosity B of the formula (5A). Furthermore, in the manufacturing method of the fifth embodiment, the decomposition treatment mixture X2 is prepared using two line mixers 30, 30A, and the decomposition treatment mixture Y2 is prepared using two line mixers 30B, 30C, so that the mixed state of the molten waste plastic and the raw oil can be further improved, the amount of molten waste plastic to be treated can be increased, and more decomposition treatment mixture to be decomposed can be prepared.

Sixth Embodiment
The sixth embodiment will be described focusing on the differences from the first to fifth embodiments, and the description of similar matters will be omitted or simplified by using the same reference numerals, for example.
The sixth embodiment is an example of carrying out a manufacturing method using a waste plastic processing system shown in Fig. 6. First, the processing system 600 shown in Fig. 6 will be described, and then the manufacturing method of the sixth embodiment will be described.

<Overall composition>
6 differs from the processing system 200 described in the second embodiment in that the processing system 600 includes an additional feedstock oil supply line 70. The other points are the same as those of the second embodiment.

<Additional Feedstock Oil Supply Line 70>
The additional feedstock oil supply line 70 is similar to the additional feedstock oil supply line 70 of the fifth embodiment.

[Manufacturing method of the sixth embodiment]
The manufacturing method of the sixth embodiment is the same as that of the second embodiment, except that the first preparation step is carried out in the following manner. The manufacturing method of the sixth embodiment will be described, focusing on the differences from the second embodiment.

<First preparation step>
The first preparation step of the sixth embodiment further includes an additional raw material supply step. The first preparation step mixes the molten waste plastic, the raw material oil, and the additional raw material oil in the first storage tank 60 to prepare a molten waste plastic mixed oil.

The temperature of the feedstock in the additional feedstock supply line 70 is preferably in the same range as in the fifth embodiment and is preferably controlled in the same manner as in the fifth embodiment.

It is preferable that the mixing conditions in the first storage tank 60 (mixing temperature and rotation speed of the rotor 80) and the melt viscosity (viscosity B) of the molten waste plastic mixed oil prepared in the first storage tank 60 are in the same range as in the first embodiment.

＜Effects＞
According to the manufacturing method of the sixth embodiment, the percentage of the mixture for decomposition processing that passes through the filter can be increased to 90 mass% or more, thereby obtaining a mixture for waste plastic decomposition processing that has improved mixability between molten waste plastic and raw oil, and improved decomposition ability of waste plastic.
In the manufacturing method of the sixth embodiment, by appropriately selecting the type of additional raw oil, it becomes easier to adjust the viscosity of the molten waste plastics supplied to the first storage tank 60, and it becomes easier to prepare a molten waste plastic mixed oil that satisfies the viscosity B of the formula (5A), and to prepare a mixture for decomposition treatment that satisfies the viscosity C of the formula (2) and the viscosity ratio (the viscosity C/the viscosity B) of the formula (3). As a result, it becomes easier to transport the mixture for decomposition treatment to the RFCC device 50, and the waste plastics can be decomposed efficiently.

Seventh Embodiment
The manufacturing method of the seventh embodiment is a manufacturing method for a waste plastic decomposition processing mixture for decomposing waste plastics in a decomposition processing device, and includes a first preparation step of preparing a molten waste plastic mixed oil by mixing molten waste plastics melted in a melting device and raw oil supplied from one or more first supply lines in a stirring tank equipped with a first stirring means, and a second preparation step of preparing a waste plastic decomposition processing mixture by mixing the molten waste plastic mixed oil prepared in the first preparation step with raw oil supplied from one or more second supply lines in a line mixing device equipped with a second stirring means.
In the manufacturing method of the seventh embodiment, when the melt viscosity of the molten waste plastic is viscosity A, the melt viscosity of the molten waste plastic mixed oil prepared in the first preparation step is viscosity B, and the melt viscosity of the waste plastic decomposition mixture prepared in the second preparation step is viscosity C, the viscosity A satisfies the following formula (Math. 1), the viscosity ratio of the viscosity B to the viscosity A (the viscosity B/the viscosity A) satisfies the following formula (Math. 2X), and the viscosity ratio of the viscosity C to the viscosity B (the viscosity C/the viscosity B) satisfies the following formula (Math. 3). The first preparation step and the second preparation step are carried out so that when the waste plastic decomposition mixture is passed through a 40 mesh filter, the passing ratio of the waste plastic decomposition mixture through the filter is 90% by mass or more.
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
Viscosity B/Viscosity A≦1/1…(Several 2X)
Viscosity C/Viscosity B≦1/20…(Math. 3)
(In the above formulas (1), (2X), and (3), the viscosity A, the viscosity B, and the viscosity C are all melt viscosities (mPa·s) at 200° C.)

The inventors have discovered that by gradually mixing molten waste plastics and raw oil so as to satisfy the viscosity A of formula (1), the viscosity ratio (said viscosity B/said viscosity A) of formula (2X), and the viscosity ratio (said viscosity C/said viscosity B) of formula (3), it is possible to increase the proportion of the waste plastic decomposition processing mixture that passes through a 40 mesh filter to 90 mass% or more.
Therefore, according to the manufacturing method of the seventh embodiment, the mixability of the molten waste plastics and the raw oil is improved, and a mixture for waste plastic decomposition processing is obtained that can improve the decomposition ability of the waste plastics.

The first preparation step is carried out so that the viscosity ratio of the viscosity B to the viscosity A (the viscosity B/the viscosity A) satisfies the following formula (Mathematical Formula 2X). The viscosity ratio (the viscosity B/the viscosity A) preferably satisfies the following formula (Mathematical Formula 2Y), and more preferably satisfies the following formula (Mathematical Formula 2Z).
Viscosity B/Viscosity A≦1/1…(Several 2X)
Viscosity B/Viscosity A≦1/100…(Math. 2Y)
Viscosity B/Viscosity A≦1/100,000…(Math. 2Z)
(Viscosity A and viscosity B are melt viscosities (mPa·s) at 200° C.)
When the viscosity ratio (said viscosity B/said viscosity A) satisfies the above formula (Mathematical formula 2X), it is easy to prepare a mixture for waste plastic decomposition processing that is in a state of sufficient mixability.

The manufacturing method of the seventh embodiment is a manufacturing method in which the formula (Math. 2) in the manufacturing method of the first embodiment is replaced with the formula (Math. 2X). That is, the manufacturing method of the seventh embodiment is similar to the manufacturing method of the first embodiment, except that the first preparation step and the second preparation step are carried out so as to satisfy the viscosity A of the formula (Math. 1), the viscosity ratio (the viscosity B/the viscosity A) of the formula (Math. 2X), and the viscosity ratio (the viscosity C/the viscosity B) of the formula (Math. 3).
Therefore, the manufacturing method of the seventh embodiment can be carried out using the processing system shown in Figures 1 to 6 described in the first to sixth embodiments, and the same effects as those obtained in the first to sixth embodiments can be obtained.

The configuration common to the first to seventh embodiments will be described.

<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 is preferably selected appropriately depending on the specifications of the melting device.
Examples of non-chlorinated plastics include polyethylene, polypropylene, propylene ethylene copolymers, polystyrene, polybutene, ethylene oligomers, butene oligomers, styrene oligomers, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, nylon, epoxy resins, and phenolic resins.
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 plastics preferably include 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, etc.).
It is more preferable that the waste plastics include at least one of polyethylene-derived waste plastics and polypropylene-derived waste plastics.
The waste plastics are preferably substantially free of waste plastics derived from polystyrene and waste plastics derived from ethylene vinyl acetate. Substantially free means that the content of waste plastics derived from polystyrene and waste plastics 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 plastics.

<Feedstock oil>
The feedstock oil is not particularly limited, but is preferably at least one selected from the group consisting of heavy cracked gas oil (HCO), cracked residual oil (CLO), atmospheric residual oil (RC), desulfurized residual oil (DSRC), desulfurized vacuum gas oil (VHHGO), undesulfurized vacuum gas oil (VGO), undesulfurized vacuum residual oil (VC), and mineral oil (e.g., HG500 (mineral oil of 500 neutral fraction)), and more preferably at least one selected from the group consisting of desulfurized vacuum gas oil (VHHGO), heavy cracked gas oil (HCO), desulfurized residual oil (DSRC), and mineral oil.
In addition, the first transport line 10 for transporting the raw oil may be connected to, for example, an HCO storage tank or a CLO storage tank so as to directly supply at least one of heavy cracked light oil (HCO) and cracked residual oil (CLO) recovered in the FCC unit or the RFCC unit.
In addition, the first transport line 10 may be connected, for example, to a desulfurized residual oil (DSRC) storage tank so that the desulfurized residual oil (DSRC) produced in a heavy oil direct desulfurization unit can be directly supplied.

<Additional feedstock oil>
The additional feedstock oil is at least one selected from the group consisting of the feedstock oils (at least one selected from the group consisting of heavy cracked gas oil, cracked residual oil, atmospheric residual oil, desulfurized residual oil, desulfurized vacuum gas oil, undesulfurized vacuum gas oil, undesulfurized vacuum residual oil, and mineral oil), light hydrocarbon oil, naphtha, gas oil, and heavy hydrocarbon oil different from the feedstock oils.

<Decomposition treatment device>
Examples of the cracking treatment unit include a catalytic cracking unit (FCC unit), a residual oil fluid catalytic cracking unit (RFCC unit) (one embodiment of an FCC unit), and a hydrocracking unit.
From the viewpoint of improving the decomposition property of waste plastics, the cracking treatment device is preferably a catalytic cracking device (FCC device) or a residual oil catalytic cracking device (RFCC device).

[Other embodiments]

In any of the above-mentioned embodiments, the first preparation step uses 1 to 10 stirring tanks (in the case of FIG. 1, the first storage tank 60) to prepare the molten waste plastic mixed oil, and when there are two or more stirring tanks, it is preferable that the two or more stirring tanks are arranged in series, in parallel, or in a combination of series and parallel. The two or more stirring tanks may be the same or different from each other.
In any of the above embodiments, the first preparation step includes a first circulating oil supply step of supplying at least one of the first circulating oil and the second circulating oil to at least one of the stirring tanks (the first storage tank 60 in the case of FIG. 1) via a circulation line,
The first circulating oil is a molten waste plastic mixed oil prepared in at least one of the stirring tanks, and the second circulating oil is the waste plastic decomposition treatment mixture prepared in at least one of the line mixing devices,
It is preferable that the stirring tank to which at least one of the first circulating oil and the second circulating oil is supplied mixes at least one of the first circulating oil and the second circulating oil with the molten waste plastics and the raw material oil.

In any of the above-described embodiments, the second preparation step uses 1 to 10 line mixers (line mixer 30 in the case of FIG. 1) to prepare a mixture for waste plastic decomposition treatment, and when there are two or more line mixers, the two or more line mixers are preferably arranged in series, in parallel, or in a combination of series and parallel. The two or more line mixers may be the same or different from each other.
In addition, in any of the above embodiments, the second preparation process includes a second circulating oil supply process for supplying the second circulating oil to at least one of the line mixers (line mixer 30 in the case of FIG. 1) via a circulation line, and the second circulating oil is a mixture for waste plastic decomposition processing prepared in at least one of the line mixers, and it is preferable that the line mixer to which the second circulating oil is supplied mixes the second circulating oil, the molten waste plastic mixed oil, and the raw material oil.

Examples of the arrangement of the stirring tank, the line mixer, and the circulation line include, but are not limited to, the following arrangements.
Arrangement 1: An arrangement in which a stirring tank K1 and a line mixer M1 are arranged in series from the upstream side.
Arrangement 2: An arrangement in which the stirring tank K1 and the line mixer M1 are arranged in parallel.
Arrangement 3: Arrangement 3 is an arrangement in which an agitation tank K2 and a line mixer M3 are arranged in parallel with the agitation tank K1 and the line mixer M1 of Arrangement 1, in that order from the upstream side.
Arrangement form 4: In any of the arrangement forms 1 to 3, a circulation line is provided to supply (return) the decomposition treatment mixture prepared in the line mixing device M1 to the stirring tank K1 as a second circulating oil.
In the case of arrangement 4, the stirring tank K1 mixes the mixture for decomposition treatment supplied as the second circulating oil, the molten waste plastics, and raw material oil to prepare a molten waste plastic mixed oil.
Arrangement form 5: In any of arrangement forms 1 to 3, a circulation line is provided to supply (return) the cracking treatment mixture prepared in the line mixer M1 to the line mixer M1 as a second circulating oil.
In the case of arrangement form 5, the line mixer M1 mixes the mixture for cracking treatment supplied as the second circulating oil, the molten waste plastic mixed oil, and the raw material oil to prepare a mixture for cracking treatment.
Arrangement form 6: In any one of the arrangement forms 1 to 3, a circulation line is provided to supply (return) the molten waste plastic mixed oil prepared in the agitation tank K1 to the agitation tank K1 as the first circulating oil.
In the case of arrangement 6, the stirring tank K1 mixes the molten waste plastic mixed oil supplied as the first circulating oil, the molten waste plastic, and raw material oil to prepare the molten waste plastic mixed oil.

In any of the above-described embodiments, the first supply line and the second supply line may be the same supply line or may be different supply lines.
For example, in the first embodiment, supply line 11A (an example of a first supply line) and supply line 13 (an example of a second supply line) do not share a supply line and are therefore different supply lines.
For example, in the case of the second embodiment, the supply line 12 (an example of a first supply line) and the supply line 13 (an example of a second supply line) are branched from the same branch point B1 of the first transportation line 10 and share a supply line, so that they are the same supply line. Then, the supply line 12 and the supply line 13 are branched at the branch point B3, and the raw oil in the supply line 12 is used in the first preparation step, and the raw oil in the supply line 13 is used in the second preparation step.

In the fifth and sixth embodiments, the first preparation step includes an additional raw material supply step, but the present invention is not limited to this.
For example, in any of the above embodiments, the second preparation step may further include an additional raw material supply step. In this case, the line mixer to which the additional raw material oil is supplied mixes the molten waste plastic, the raw material oil, and the additional raw material oil to prepare a mixture for waste plastic decomposition treatment.
In the fifth and sixth embodiments, the embodiment in which the additional raw material oil is supplied to the kneader from one additional raw material supply line has been described, but is not limited thereto. For example, in any of the above embodiments, an additional raw material supply step may be provided in which additional raw material oil is supplied from one or more additional raw material supply lines to at least one of the kneader, the first storage tank, the mixed oil transport line, the first supply line, the line mixer, and the second supply line. The types of additional raw material oils to be added may be the same or different from each other.

In the fourth embodiment, an embodiment in which the second preparation step is performed using two line mixers has been described, and in the fifth embodiment, an embodiment in which the second preparation step is performed using four line mixers has been described, but the present invention is not limited to this. The number and arrangement of the line mixers are not limited to these.
For example, in any of the above-described embodiments, the second preparation step may be carried out by arranging a plurality of line mixers in series, in parallel, or in a combination of series and parallel.
The multiple line mixers may be the same or different from each other.
In any of the above embodiments, the first preparation step may be performed by arranging a plurality of first storage tanks in series, in parallel, or in a combination of series and parallel. The plurality of first storage tanks may be the same or different from each other.
In addition, the first preparation step or the second preparation step may be carried out while supplying (returning) the decomposition treatment mixture prepared in at least one of the multiple line mixers to the first storage tank, the line mixer, and the first storage tank and the line mixer via a circulation line.
In addition, the first preparation process may be carried out while supplying (returning) the molten waste plastic mixed oil prepared in at least one of a plurality of first storage tanks to one of the first storage tanks via a circulation line.

In the fifth embodiment, the first preparation step is performed using two kneaders, but the present invention is not limited to this. For example, in any of the above embodiments, the first preparation step may be performed using three or more kneaders. The multiple kneaders may be the same or different from each other. The number of kneaders is not limited.

In any of the above-described embodiments, the decomposition treatment mixture prepared in the line mixer may be supplied to the RFCC device without being stored in the second storage tank.
In any of the above embodiments, the decomposition mixture prepared in the line mixer may be fed directly to the RFCC device through the second transport line.

In any of the above-described embodiments, a known melting device may be used in place of the kneader 20, 20A.
In any of the above-described embodiments, the first storage tank 60 may be replaced with a known stirring tank.
In any of the above-described embodiments, a known line mixer may be used in place of the line mixers 30, 30A, 30B, and 30C.
In any of the above-described embodiments, the RFCC unit 50 may be replaced with, for example, a known cracking treatment unit used in the field of oil refining.

The following describes examples of the present invention. The present invention is not limited to these examples.

Example 1
[First preparation step]
A mixture of polypropylene and polyethylene was used as the waste plastic, and the waste plastic was melted under the following melting conditions.
The melt viscosity of the molten waste plastics was measured by the method described above. The melt viscosity of the molten waste plastics at 200° C. was 2.3×10 ⁷ mPa·s.
(Melting conditions)
・Kneading machine: Shibaura Machine Co., Ltd.: Twin-screw kneading extruder (model number TEM-37SS)
Melting temperature: 200°C
Melting amount: 30 kg/hr
DSRC was added as raw oil to molten waste plastic (10 kg) so that the ratio of desulfurized residual oil (DSRC) to molten waste plastic (hereinafter also referred to as "molten waste plastic") (DSRC/molten waste plastic) was 1 by mass, and a mixture C1 (20 kg) of molten waste plastic and DSRC was obtained. The mixture C1 (20 kg) was then transported to a stirring tank, and DSRC was further added as raw oil to the mixture C1 (20 kg) so that the ratio of DSRC to the molten waste plastic (DSRC/the molten waste plastic) was 3 by mass, and a molten waste plastic mixed oil was prepared under the following mixing condition 1.
(Mixing Condition 1)
・Mixing tank: Double helical ribbon impeller mixing tank ・Temperature: 200℃
・Rotation speed: 15 rpm
Average residence time: 15 minutes The melt viscosity of the molten waste plastic mixed oil was measured by the method described above. The melt viscosity of the molten waste plastic mixed oil at 200°C was 150,000 mPa·s.

[Second preparation step]
Next, DSRC (46 kg) was further added to the molten waste plastic mixed oil (4 kg) so that the ratio of DSRC to molten waste plastic (DSRC/molten waste plastic) was 49 by mass. After that, the mixture of the molten waste plastic mixed oil and the DSRC was mixed using a continuous mixer under the following mixing condition 2 to prepare a mixture for decomposition treatment.
The melt viscosity of the mixture for decomposition treatment was measured by the method described above. The melt viscosity of the mixture for decomposition treatment at 200° C. was 11 mPa·s, and when the mixture for decomposition treatment was passed through a 40 mesh filter, the passing ratio through the 40 mesh filter was 91 mass%.
(Mixing Condition 2)
・Continuous mixer: Primix: Homomic Line Flow LF30 type ・Rotation speed: 14,500 rpm
Temperature: 200°C
Time: 3 seconds

Example 2
A mixture for decomposition treatment was prepared in the same manner as in Example 1, except that the rotation speed and mixing time in the continuous mixer under mixing condition 2 were changed to 10,000 rpm and 30 seconds, respectively.
The melt viscosity of the mixture for decomposition treatment at 200° C. was 13 mPa·s, and the passing rate of the mixture for decomposition treatment that passed through a 40 mesh filter was 98 mass %.

Comparative Example 1
Comparative Example 1 is an example in which a mixture for decomposition treatment was prepared using only a continuous mixer without using a stirring tank. The mixture for decomposition treatment in Comparative Example 1 was prepared by the following method.
A mixture C1 of molten waste plastic and DSRC was obtained in the same manner as in Example 1. Thereafter, without conveying the mixture C1 to a stirring tank, DSRC was added as a raw material oil to the mixture C1 so that the ratio of DSRC to the molten waste plastic (DSRC/the molten waste plastic) was 3 by mass ratio, to prepare a molten waste plastic mixed oil D1.
Then, DSRC (46 kg) was further added to the molten waste plastic mixed oil D1 (4 kg) in the same manner as in Example 1. Then, the mixture of the molten waste plastic mixed oil D1 and the DSRC was mixed under the mixing condition 2 using a continuous mixer to prepare a mixture for decomposition treatment.
The melt viscosity of the mixture for decomposition treatment at 200° C. was 3 mPa·s, and when the mixture for decomposition treatment was passed through a 40 mesh filter, the passing rate of the mixture through the 40 mesh filter was 1 mass %.

Comparative Example 2
Comparative Example 2 is an example in which a mixture for decomposition treatment was prepared using only a stirring tank without using a continuous mixer. The mixture for decomposition treatment in Comparative Example 2 was prepared by the following method.
A mixture C1 of molten waste plastic and DSRC was obtained in the same manner as in Example 1. Then, the mixture was transported to a stirring tank, and DSRC was further added as raw material oil to the molten waste plastic so that the ratio of DSRC to the molten waste plastic (DSRC/the molten waste plastic) was 3 by mass ratio. A molten waste plastic mixed oil D2 was prepared in the same manner as in Example 1, except that the average residence time in the mixing condition 1 was changed to 30 minutes.
Next, DSRC (46 kg) was further added to the molten waste plastic mixed oil D2 (4 kg) so that the ratio of DSRC to molten waste plastic (DSRC/molten waste plastic) was 49 by mass. This mixture of the molten waste plastic mixed oil D2 and DSRC was used as a mixture for decomposition treatment of Comparative Example 2.
The melt viscosity of the mixture for decomposition treatment at 200° C. was 5 mPa·s, and when the mixture for decomposition treatment was passed through a 40 mesh filter, the passing rate through the 40 mesh filter was 65 mass%.

〔evaluation〕
(Viscosity B and Viscosity C)
The melt viscosity (viscosity B) of the molten waste plastic mixed oil at 200°C and the melt viscosity (viscosity C) of the mixture for waste plastic decomposition processing at 200°C were measured by the method described above.

(Percentage of decomposition mixture passing through 40 mesh filter)
When the mixture for decomposition treatment was passed through a 40 mesh filter, the passing rate of the filter was calculated by the following method.
5 kg of the mixture for decomposition treatment prepared in each example was passed through a 40 mesh filter under its own weight under conditions of normal temperature and normal pressure (25° C., 1 atm).
The passing rate (unit: %) of the 40 mesh filter was calculated by the following formula (number X).
Proportion of the mixture for decomposition treatment that passed through the 40 mesh filter = A/(A+B) x 100...(number X)
A: Weight of the filtrate of the mixture for decomposition treatment passed through a 40 mesh filter [g]
B: Weight of the mixture for decomposition treatment that did not pass through the 40 mesh filter [g]

(Explanation in Table 1)
The viscosity B of Comparative Example 1 indicates the viscosity value of the molten waste plastic mixed oil D1.
The viscosity C of Comparative Example 2 indicates the viscosity value of a mixture of molten waste plastic mixed oil D2 and DSRC.

The mixtures for decomposition treatment in Examples 1 and 2 obtained by stepwise mixing of molten waste plastics and raw oil using a stirring tank and a continuous mixer so as to satisfy the above formulas (1) to (3) or the above formulas (1), (2X) and (3) had a high passing rate of 90% or more through a 40 mesh filter.
On the other hand, the mixture for decomposition treatment in Comparative Example 1, which was prepared using only a continuous mixer without using a stirring tank, had a melt viscosity (viscosity C) that remained almost the same as the viscosity of the DSRC (3 mPa·s). Furthermore, the passing rate of the mixture through the 40 mesh filter in Comparative Example 1 was remarkably low at 1%.
In addition, the mixture for decomposition treatment in Comparative Example 2, which was prepared using only a stirring tank without using a continuous mixer, had a low passing rate through a 40 mesh filter of 65%, because the mixing of the molten waste plastics into the raw oil was insufficient using only a stirring tank.
From the above results, it can be seen that by producing a mixture for cracking treatment according to the method of this embodiment, a mixture for cracking treatment with improved mixability between molten waste plastics and raw oil can be obtained. By decomposing such a mixture for cracking treatment in a cracking treatment device, the decomposition ability of waste plastics can be improved.

The method for producing a mixture for decomposing waste plastics of the present invention can increase the effective utilization rate of waste plastics and therefore can be used industrially.

10...first transport line, 11, 11A, 12...supply line (first supply line), 13...supply line (second supply line), 13A...first raw oil supply line, 13B...second raw oil supply line, 14...second transport line, 15...mixed oil transport line, 20, 20A...kneader, 21...feeder, 22...hopper, 23...waste plastic supply line, 24...feeder controller, 25...waste plastic supply control means, 30, 30A, 30B, 30C...line mixer, 40...second storage tank, 41...centrifugal pump, 43, 44...gas venting line, 50...RFCC device, 60...first storage Tank, 61... gear pump, 70... additional feedstock oil supply line, 80... rotor, 90... agitator blade, 100, 200, 300, 400, 500, 600... treatment system, 111... first feedstock oil supply control means, 112... first control valve, 113... first controller, 121... second feedstock oil supply control means, 122... second control valve, 123... second controller, 131... third feedstock oil supply control means, 132... third control valve, 133... third controller, 151... first mixed oil transport line, 152... second mixed oil transport line, 171... additional feedstock oil supply control means, 172... fourth control valve, 173... fourth controller, HG... heat exchanger.

Claims (18)

A method for producing a mixture for decomposing waste plastics in a decomposition treatment device, comprising:
A first preparation step of preparing a molten waste plastic mixed oil by mixing the molten waste plastic melted in the melting device and the raw material oil supplied from one or more first supply lines in a stirring tank equipped with a first stirring means;
A second preparation step of preparing a mixture for waste plastic decomposition processing by mixing the molten waste plastic mixed oil prepared in the first preparation step with raw material oil supplied from one or more second supply lines in a line mixer equipped with a second stirring means,
The melt viscosity of the molten waste plastic is viscosity A, the melt viscosity of the molten waste plastic mixed oil prepared in the first preparation step is viscosity B, and the melt viscosity of the waste plastic decomposition treatment mixture prepared in the second preparation step is viscosity C.
The viscosity A satisfies the following formula (Formula 1):
The viscosity C satisfies the following formula (Formula 2),
The first preparation step and the second preparation step are carried out so that a viscosity ratio of the viscosity C to the viscosity B (the viscosity C/the viscosity B) satisfies the following mathematical formula (Mathematical formula 3),
When the waste plastic decomposition mixture is passed through a 40 mesh filter, the passing rate of the waste plastic decomposition mixture through the filter is 90% by mass or more;
A method for manufacturing a mixture for decomposing waste plastics.
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
5.0mPa・s<Viscosity C≦50mPa・s…(Equation 2)
Viscosity C/Viscosity B≦1/20…(Math. 3)
(In the above formulas (1) to (3), the viscosity A, the viscosity B, and the viscosity C are all melt viscosities (mPa·s) at 200° C.) A method for producing a mixture for decomposing waste plastics in a decomposition treatment device, comprising:
A first preparation step of preparing a molten waste plastic mixed oil by mixing the molten waste plastic melted in the melting device and the raw material oil supplied from one or more first supply lines in a stirring tank equipped with a first stirring means;
A second preparation step of preparing a mixture for waste plastic decomposition processing by mixing the molten waste plastic mixed oil prepared in the first preparation step with raw material oil supplied from one or more second supply lines in a line mixer equipped with a second stirring means,
The melt viscosity of the molten waste plastic is viscosity A, the melt viscosity of the molten waste plastic mixed oil prepared in the first preparation step is viscosity B, and the melt viscosity of the waste plastic decomposition treatment mixture prepared in the second preparation step is viscosity C.
The viscosity A satisfies the following formula (Formula 1):
A viscosity ratio of the viscosity B to the viscosity A (the viscosity B/the viscosity A) satisfies the following formula (Formula 2X),
The first preparation step and the second preparation step are carried out so that a viscosity ratio of the viscosity C to the viscosity B (the viscosity C/the viscosity B) satisfies the following mathematical formula (Mathematical formula 3),
When the waste plastic decomposition mixture is passed through a 40 mesh filter, the passing rate of the waste plastic decomposition mixture through the filter is 90 mass% or more;
A method for manufacturing a mixture for decomposing waste plastics.
1.0×10 ⁶ mPa·s≦Viscosity A≦1.0×10 ⁸ mPa·s (Equation 1)
Viscosity B/Viscosity A≦1/1…(Several 2X)
Viscosity C/Viscosity B≦1/20…(Math. 3)
(In the above formulas (1), (2X), and (3), the viscosity A, the viscosity B, and the viscosity C are all melt viscosities (mPa·s) at 200° C.) In the method for producing a mixture for waste plastic decomposition processing according to claim 1 or 2,
The first supply line and the second supply line are the same supply line or different supply lines.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 3,
The first preparation step prepares the molten waste plastic mixed oil using 1 to 10 stirring tanks,
When the number of the stirring tanks is two or more, the two or more stirring tanks are arranged in series, in parallel, or in a combination of series and parallel.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition treatment according to claim 4,
The first preparation step includes a first circulating oil supply step of supplying at least one of a first circulating oil and a second circulating oil to at least one of the stirring tanks via a circulation line,
The first circulating oil is the molten waste plastic mixed oil prepared in at least one of the stirring tanks,
The second circulating oil is the mixture for waste plastic decomposition treatment prepared in at least one of the line mixers,
The stirring tank to which at least one of the first circulating oil and the second circulating oil is supplied mixes at least one of the first circulating oil and the second circulating oil, the molten waste plastic, and the raw material oil.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 5,
The second preparation step prepares the mixture for waste plastic decomposition treatment using 1 to 10 of the line mixers,
When the number of the line mixers is two or more, the two or more line mixers are arranged in series, in parallel, or in a combination of series and parallel.
A method for manufacturing a mixture for decomposing waste plastics. 7. The method for producing a mixture for waste plastic decomposition treatment according to claim 6,
The second preparation step includes a second circulating oil supply step of supplying a second circulating oil to at least one of the line mixers via a circulation line,
The second circulating oil is the mixture for waste plastic decomposition treatment prepared in at least one of the line mixers,
The line mixer to which the second circulating oil is supplied mixes the second circulating oil, the molten waste plastic mixed oil, and the raw material oil.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 4 to 7,
The process further includes an additional feedstock supply step of supplying at least one additional feedstock selected from the group consisting of the feedstock oil, light hydrocarbon oil, naphtha, diesel, and heavy hydrocarbon oil different from the feedstock oil from one or more additional feedstock supply lines.
A method for manufacturing a mixture for decomposing waste plastics. The method for producing a mixture for waste plastic decomposition processing according to claim 8,
The first preparation step further includes an additional raw material supply step of supplying the additional raw material oil to at least one of the stirring tanks,
The stirring tank to which the additional raw material oil is supplied mixes the additional raw material oil, the molten waste plastic, and the raw material oil.
A method for manufacturing a mixture for decomposing waste plastics. In the waste plastic production method according to claim 8 ,
The second preparation step further includes an additional raw material supply step of supplying the additional raw material oil to at least one of the line mixers;
The line mixer to which the additional raw material oil is supplied mixes the additional raw material oil, the molten waste plastic mixed oil, and the raw material oil;
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 10,
The mixing in the stirring tank in the first preparation step is performed under conditions of a temperature of 175° C. or higher and 260° C. or lower and a rotation speed of the first stirring means of 3 rpm or higher and 1,000 rpm or lower.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 11,
A method for producing a mixture for waste plastic decomposition processing, wherein mixing in the line mixer in the second preparation step is carried out under conditions of a temperature of 160°C or higher and 260°C or lower and a rotation speed of the second stirring means of 10 rpm or higher and 20,000 rpm or lower. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 12,
The melting temperature of the waste plastic melted in the melting device is 175° C. or higher and 260° C. or lower,
The temperature of the raw oil in the first supply line is 80° C. or more and 240° C. or less,
The temperature of the raw oil in the second supply line is 80° C. or more and 240° C. or less.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 13,
The feedstock oil is at least one selected from the group consisting of heavy cracked gas oil, cracked residual oil, atmospheric residual oil, desulfurized residual oil, desulfurized vacuum gas oil, undesulfurized vacuum gas oil, undesulfurized vacuum residual oil, and mineral oil;
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 14,
The melting device is a kneader.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 15,
The line mixing device is any one of an in-line mixer, a line mixer, and a continuous mixer.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 16,
The cracking treatment device is a fluid catalytic cracking device.
A method for manufacturing a mixture for decomposing waste plastics. In the method for producing a mixture for waste plastic decomposition processing according to any one of claims 1 to 17,
The molten waste plastic is a melt of waste plastic containing at least one of polyethylene-derived waste plastic and polypropylene-derived waste plastic,
A method for manufacturing a mixture for decomposing waste plastics.

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