Apparatus for converting waste plastic to oil

Abstract

To safely enable production of recycled oil without lowering a thermal decomposition reaction in waste plastic as a raw material, maintain production efficiency of the recycled oil to be higher, and improve thermal efficiency, when the waste plastic is thermally decomposed and the recycled oil is produced.SOLUTION: An apparatus for converting waste plastic to oil having a thermal decomposition vessel for thermally decomposing waste plastic and producing decomposition gas, and a cooling separation device for gas-liquid separating the decomposition gas obtained in the thermal decomposition vessel a plurality of times, and obtaining liquid recycled oil has an extruder for raw material charge for heating and conveying the waste plastic, and a heating line for raw material charge which further heats melted waste plastic which is melted and conveyed by the extruder for raw material charge and sends the heated melted waste plastic to the thermal decomposition vessel, wherein the heating line for the raw material charge has a heating part for raising the temperature of the waste plastic to be equal to or higher than a thermal decomposition temperature, and an inclined part inclined upward from the extruder for raw material charge to a waste plastic supply port of the thermal decomposition vessel.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention relates to an apparatus for decomposing waste plastics to produce recycled oil, and more specifically, to a waste plastic oil-reforming processing apparatus that can decompose waste plastics to produce recycled oil, and can also heat and melt the waste plastics used as raw material and send them to a pyrolysis furnace. [Background technology]

[0002] Conventionally, various methods have been considered for recycling plastics, including decomposing waste plastics to obtain recycled oil, etc. One known example of such a method involves melting waste plastics and sending them to a pyrolysis vessel, which then pyrolyzes the waste plastics to generate decomposition gas, which is then liquefied to obtain recycled oil (Patent Document 1, etc.). The waste plastics used as raw materials include polyolefins such as polyethylene and polypropylene, and polystyrene. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-170986 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when waste plastics as raw material are fed into a pyrolysis vessel in a solid state, the temperature inside the pyrolysis vessel drops every time the raw material is fed, significantly slowing down the rate of the pyrolysis reaction. To prevent this, it is possible to feed the raw waste plastics in a molten state into the pyrolysis tank. However, if the heating temperature exceeds the decomposition temperature of the waste plastics, the waste plastics will decompose, generating decomposition gases, which may affect the equipment and safety of people. On the other hand, it is possible to heat the waste plastics to a temperature at which pyrolysis does not occur, but in this case, the temperature of the waste plastics fed in is lower than the temperature inside the thermal reaction tank, and the rate of the pyrolysis reaction will decrease slightly each time the waste plastics are fed in. Therefore, the object of this invention is to produce recycled oil by pyrolyzing waste plastics safely without causing a decrease in the pyrolysis reaction of the raw material waste plastics, while maintaining high production efficiency of the recycled oil and improving thermal efficiency. [Means for solving the problem]

[0005] The present invention solves the above-mentioned problems by using an apparatus for efficiently removing pyrolysis residue from a pyrolysis furnace, and the gist of the invention resides in the following [1] to [6]. [1] A waste plastic oil treatment device having a pyrolysis tank that thermally decomposes waste plastic to generate decomposition gas, and a cooling and separation device that performs gas-liquid separation of the decomposition gas obtained in the pyrolysis tank multiple times to obtain liquid recycled oil. The device also has a raw material input extruder that heats and transports the waste plastic, and a raw material input heating line that further heats the molten waste plastic melted by the raw material input extruder and transported, and sends it to the pyrolysis tank. The raw material input heating line has a heating section that raises the temperature of the waste plastic to above the pyrolysis temperature, and has an upwardly sloping section from the raw material input extruder to the waste plastic supply port of the pyrolysis tank.

[0006] [2] The cooling and separation device is a device that separates the liquid recycled oil and the gaseous gas components by cooling, and has a heating unit for heating the pyrolysis tank on the outer periphery of the pyrolysis tank, and the heating means of the heating unit is at least one selected from an oil burner that uses the recycled oil as fuel and a gas burner that uses the gas components as fuel. [1] The waste plastic oil treatment device described in [1]. [3] The raw material input extruder has a heating section for heating waste plastic, and the heating means for heating at least one of the heating section of the raw material input extruder and the heating section of the raw material input heating line is the exhaust gas of the oil burner and the exhaust gas of the gas burner.

[0007] [4] A method for producing recycled oil, in which waste plastics are thermally decomposed in a pyrolysis tank to generate decomposition gas, and then the decomposition gas obtained in the pyrolysis tank is subjected to gas-liquid separation multiple times using a cooling separation device to obtain liquid recycled oil, in which the waste plastics are heated and transported to the pyrolysis tank by a raw material input extruder and a raw material input heating line, the waste plastics are heated and melted by the raw material input extruder and transported to the raw material input heating line, the molten waste plastics are further heated by the raw material input heating line and sent to the pyrolysis tank, and the raw material input heating line has a heating section that raises the temperature of the waste plastics above the pyrolysis temperature, and has an upwardly inclined portion from the raw material input extruder to the waste plastic supply port of the pyrolysis tank.

[0008] [5] A method for producing recycled oil as described in [4], in which the liquid recycled oil and gaseous gas components are separated by cooling using the cooling separation device, and a heating section for heating the pyrolysis tank is provided on the outer periphery of the pyrolysis tank, and the heating section is heated by at least one selected from an oil burner that uses the recycled oil as fuel and a gas burner that uses the gas components as fuel. [6] A method for producing recycled oil described in [5], wherein a heating section for heating waste plastic is provided in the raw material input extruder, and at least one of the heating section of the raw material input extruder and the heating section of the raw material input heating line is heated by the exhaust gas of the oil burner and the exhaust gas of the gas burner. Effect of the Invention

[0009] By using the waste plastic oil refining treatment device of this invention, the raw waste plastic can be fed into the pyrolysis tank without slowing down the rate of the pyrolysis reaction in the pyrolysis tank, allowing the pyrolysis reaction to proceed efficiently. In addition, the waste plastic raw material fed into the pyrolysis tank is fed into the pyrolysis tank in a state in which decomposition gas is generated by the pyrolysis reaction. The decomposition gas generated in the raw material input heating line is sent directly to the pyrolysis tank and treated as raw material, and the decomposition gas is prevented from flowing back into the raw material input extruder and leaking out. This prevents a decrease in pyrolysis efficiency and ensures the safety of the equipment and personnel.

[0010] In addition, when recycled oil is produced using the waste plastic oil treatment device of the present invention, gas components are generated, including gases with low molecular weights that are to be exhausted and released into the atmosphere. In this case, the recycled oil and these gas components, especially the gases to be exhausted, can be burned with an oil burner or gas burner and used to heat the pyrolysis furnace, so that the recycled oil produced in the device itself and the gas components to be exhausted can be effectively used, instead of using external fuel. Furthermore, since the exhaust gas generated by the oil burner or gas burner can be used to heat the raw material input extruder or the raw material input heating line, the heat of the exhaust gas generated by the oil burner or gas burner can be effectively utilized. [Brief description of the drawings]

[0011] [Figure 1]FIG. 1A is a schematic diagram showing an example of a pyrolysis tank and a pyrolysis residue transporting extruder of a waste plastic oil treatment device according to the present invention; FIG. 1B is a plan view showing an example of a fin provided at the bottom of the pyrolysis tank; and FIG. 1C is a perspective view showing an example of a portion of a heating line for introducing raw material into the pyrolysis tank. [Diagram 2] FIG. 1 is a schematic diagram showing an example of a waste plastic oil-recovery treatment device according to the present invention. [Diagram 3] FIG. 1 is a schematic diagram showing another example of a waste plastic oil-recovery treatment device according to the present invention. [Figure 4] Schematic diagram showing an example of the fractional distillation apparatus used in FIG. 3. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The waste plastic oil treatment device of the present invention, as shown in Figures 1(a) and 2, is an apparatus having a pyrolysis furnace 11 having a pyrolysis vessel 11a that thermally decomposes waste plastic to generate decomposition gas, and a cooling and separation device that performs gas-liquid separation multiple times on the decomposition gas obtained in the pyrolysis vessel 11a to obtain liquid recycled oil. This cooling separation device is a device that separates the liquid recycled oil from the gaseous gas components by cooling, and in the device shown in Figures 2 and 3 of the present invention, examples of the cooling separation device include a reflux tower 14, a condenser 13 (13a, 13b), etc., as described later, and also includes a cooling separation device consisting of a first product oil tank 15, a cooler 15a, a fractionation device 41 if used, and a cooling separation device consisting of a group of devices including each of the surrounding lines. Therefore, in the device of Figures 2 and 3 of the present invention, gas-liquid separation is performed four times.

[0013] Examples of waste plastics to be treated in this invention include polyolefins such as polyethylene and polypropylene, polystyrene, polyamides, and the like. In addition, components obtained by thermally decomposing waste plastics using the waste plastic oil treatment device according to the present invention include liquid components such as recycled oil liquefied in the cooling and separating device, gas components that were not liquefied in the cooling and separating device, wax components that are solid at room temperature due to insufficient decomposition, and solid components such as carbonized products that have been decomposed too far, etc. Among these, the solid components such as wax components and carbonized products remain in the thermal decomposition vessel 11a as pyrolysis residues.

[0014] [Pyrolysis furnace] As shown in FIG. 1(a), the pyrolysis furnace 11 is composed of a pyrolysis vessel 11a for carrying out pyrolysis, a heating section 11b provided on the outer periphery of the pyrolysis vessel 11a, and a stirrer 11c.

[0015] The pyrolysis vessel 11a is a vessel for pyrolyzing the waste plastic. The temperature of the pyrolysis vessel 11a is preferably 370°C or higher, more preferably 380°C or higher, and more preferably 400°C or higher. If the temperature is lower than 370°C, the pyrolysis of the waste plastic is difficult to occur, and the pyrolysis time tends to be long. The temperature is preferably 450°C or lower, and more preferably 400°C or lower. If the temperature is higher than 450°C, the pyrolysis speed increases, and the decomposition gas is further decomposed into low molecular weight gases, or the decomposition proceeds too far, which may increase the amount of pyrolysis residue such as charcoal.

[0016] The temperature of the pyrolysis vessel 11a is increased by heating a heating medium, such as a gas such as air or a heating liquid medium, contained inside the heating section 11b by at least one of an oil burner 11e and a gas burner 11f, and the temperature inside the vessel can be adjusted by adjusting the degree of heating. In addition, when the oil burner 11e is used as a heating means for the pyrolysis vessel 11a, the recycled oil such as heavy oil and light oil obtained in the waste plastic oil treatment device of this invention can be effectively used as described later, and when the gas burner 11f is used as a heating means for the pyrolysis vessel 11a, the gas components generated in the waste plastic oil treatment device of this invention can be effectively used as described later. Among these, the gas burner 11f using the gas components as fuel is particularly preferable because it can effectively use the gas components discharged into the atmosphere as exhaust gas or burned at the outlet. The temperature of the heating medium is preferably 580° C. or higher, and more preferably 600° C. or higher. The upper limit of the temperature is preferably 720° C. or lower, and more preferably 700° C. or lower. If the temperature is outside this range, the temperature inside the pyrolysis vessel 11a may not be able to be maintained within the above range.

[0017] At least one outlet 11j for extracting the pyrolysis residue is provided at the bottom 11g of the pyrolysis tank 11a. As described later, in the pyrolysis residue removal process, the pyrolysis residue is heated together with the surrounding molten waste plastics to become fluid, and the pyrolysis residue can be extracted from the outlet 11j.

[0018] The bottom 11g of the pyrolysis vessel 11a has a flat shape as shown in Fig. 1(a), specifically, a dish-shaped flat end plate with a flat central portion. The peripheral surface of the pyrolysis vessel 11a and the bottom 11g are connected via a curved surface, which prevents the pyrolysis residue from accumulating at the connection between the peripheral surface and the bottom 11g. It is preferable to provide fins 11r, i.e., a heat transfer plate, on the outer surface of the bottom 11g of the pyrolysis vessel 11a, i.e., on the surface of the bottom 11g on the side where the heating unit 11b is provided, as shown in Fig. 1(b). By providing these fins 11r, the heat of the heating medium heated in the heating unit 11b can be efficiently transferred to the pyrolysis vessel 11a, and the pyrolysis vessel 11a can be efficiently heated. The fins 11r are linear or curved plate-like bodies having a predetermined height, and their intervals and directions can be set appropriately so as to efficiently transfer heat to the pyrolysis vessel 11a. For example, all the fins 11r can be arranged in parallel, or as shown in Fig. 1(b), the fins 11r can be arranged in parallel, but some of the fins 11r can be arranged in a different direction from the remaining fins 11r, for example, at right angles.

[0019] The peripheral portion is provided with the aforementioned outlet 11j, and the pyrolysis residue that has flowed to the peripheral portion can be discharged from this outlet 11j. In order to efficiently discharge the residue, the stirring blades 11m and 11n of the stirrer 11c have a structure that can scrape the residue to the outer periphery of the pyrolysis vessel, as described later.

[0020] A waste plastic supply port 11h is provided on the upper side wall of the pyrolysis vessel 11a. If the waste plastic supplied from this supply port 11h is melted and has a temperature similar to or close to that of the inside of the pyrolysis vessel 11a, it is preferable from the viewpoint of thermal efficiency because it is possible to suppress a decrease in the temperature inside the pyrolysis vessel 11a.

[0021] A stirrer 11c is disposed in the pyrolysis vessel 11a to stir the molten waste plastics inside. The stirrer 11c has stirring blades 11m and 11n on a stirring shaft 11k, and is stirred by a stirring motor 11p. The stirring blade 11m disposed at the tip of the stirring shaft 11k, i.e., the position closest to the bottom 11g of the pyrolysis vessel 11a, stirs the contents near the bottom 11g so that they do not stagnate. The shape of the stirring blade 11m is preferably such that when the stirrer 11c is rotated, a force acts to push the molten waste plastics, which are the contents of the pyrolysis vessel 11a, outward, for example, a shape having a curve facing in the opposite direction to the rotation direction. In this way, the contents, especially solids such as pyrolysis residue, can be sent outward, and the pyrolysis residue can be moved to the peripheral part of the bottom 11g, which is the lowest position of the bottom 11g. In addition, the shape of the stirring blade 11n provided at a portion other than the tip of the stirring shaft 11k is preferably such that a force that pushes the contents of the pyrolysis vessel 11a downward is applied when the stirrer 11c is rotated. In this way, it becomes possible to send the contents, particularly solids such as pyrolysis residue, downward.

[0022] [Raw material feeding equipment - raw material feeding extruder and raw material feeding heating line] The waste plastics as raw material are fed using a waste plastics feeding device as shown in Fig. 1(a). This device has a raw material feeding extruder 12a for heating and transporting the waste plastics, and a raw material feeding heating line 12e for further heating the molten waste plastics melted by the raw material feeding extruder 12a and transported, and sending it to the pyrolysis furnace 11a. The raw material input extruder 12a constituting the raw material input device is composed of an extruder body 12b, a heating section 12c for heating the extruder body 12b, and an input port 12d for inputting raw material waste plastic. In the raw material input extruder 12a, waste plastic is input to the input port 12d, melted while being crushed in the extruder body 12b, and sent to the pyrolysis vessel 11a via the raw material input heating line 12e. The temperature of the extruder body 12b is heated by the heating section 12c and used to melt the waste plastic. The temperature of the extruder body 12b is preferably 200°C or higher, preferably 240°C or higher, and more preferably 260°C or higher. If it is less than 200°C, there is a risk that the waste plastic cannot be sufficiently melted. On the other hand, the upper limit is preferably lower than 370°C, which is the thermal decomposition temperature of the waste plastic, and is preferably 300°C or lower, and more preferably 280°C or lower. If the temperature is above 370°C, it exceeds the thermal decomposition temperature of the waste plastic, and there is a risk of thermal decomposition occurring inside the extruder.

[0023] Next, the waste plastics (hereinafter, sometimes referred to as "molten raw materials") extruded from the extruder body 12b passes through the raw material input heating line 12e. This raw material input heating line 12e has an upwardly inclined portion from the raw material input extruder 12a to the waste plastics supply port 11h of the pyrolysis vessel 11a. This raw material input heating line 12e is a line for further increasing the temperature of the molten raw material obtained by the raw material input extruder 12a by the heating section 12f, and increasing the temperature to near the pyrolysis temperature. By increasing the temperature to near the pyrolysis temperature, even if the molten raw material is input into the pyrolysis vessel 11a, the internal temperature of the pyrolysis vessel 11a is prevented from falling below the pyrolysis temperature of the molten raw material, and the pyrolysis rate can be prevented from decreasing. The pyrolysis temperature of the molten raw material is generally 370°C or higher, depending on the raw material.

[0024] As shown in Fig. 1(a), the raw material input heating line 12e has an upwardly inclined slope from the raw material input extruder 12a to the pyrolysis vessel 11a, and the heating section 12f is mainly arranged on this slope. The raw material input heating line 12e heats the waste plastic to a temperature higher than the pyrolysis temperature, so that pyrolysis starts to occur therein, and decomposition gas is generated. The inclination of the raw material input heating line 12e is preferably 30° to 70° upward from the horizontal plane, more preferably 45° to 70°. By setting the inclination within this range, it is possible to prevent the generated decomposition gas from flowing back into the raw material input extruder 12a, and to send the molten waste plastics conveyed by the raw material input extruder 12a to the pyrolysis furnace 11a. If the inclination angle is lower than the range, the generated decomposition gas may flow back into the raw material input extruder 12a, and if the inclination angle is higher than the range, the amount of work applied by the raw material input extruder 12a may be insufficient to send the molten waste plastics to the pyrolysis furnace 11a, resulting in a too slow speed, which may result in a decrease in efficiency, or in some cases, the waste plastics may not be sent to the pyrolysis furnace 11a.

[0025] As a means for heating the heating section 12c of the raw material input extruder 12a and the heating section 12f of the raw material input heating line 12e, there are methods using an oil burner or a gas burner using an external fuel, a recycled oil obtained in the waste plastic oil treatment device according to the present invention, a gas component not condensed in the cooling and separating device described later, and in particular, a second uncondensed gas not condensed in the condenser 13b described later as a fuel. In addition, when the oil burner 11e or the gas burner 11f is used to heat the pyrolysis vessel 11a, the high-temperature exhaust gas generated around the oil burner 11e or the gas burner 11f can be used. In particular, the exhaust gas generated in the oil burner 11e or the gas burner 11f is 400°C to 700°C, so by using these exhaust gases, the heat of the exhaust gas can be effectively utilized and the thermal efficiency can be improved.

[0026] Fins 12g, i.e., heat transfer plates, as shown in Fig. 1(a) and 1(c) are arranged on the outside of the straight section of this raw material input heating line 12e, particularly on the side connected to the pyrolysis furnace 11a, and the heating section 12f is arranged up to the vicinity of the heating section 11b of the pyrolysis furnace 11 or in contact with the heating section 11b, so that the heat of the heating section 12f can be transferred more efficiently to the raw material input heating line 12e, and the molten raw material in the raw material input heating line 12e can be heated more efficiently. The fins 12g can be linear or curved plate-like bodies having a predetermined height, and are arranged over the entire length of the raw material input heating line 12e.

[0027] [Waste plastic oil processing equipment] An example of a waste plastic oil-recovery treatment apparatus using the above-mentioned pyrolysis furnace 11 is shown in FIG. First, the raw material waste plastic is melted using the above-mentioned raw material charging device, and in a state where thermal decomposition has begun, it is fed into the thermal decomposition vessel 11a through the waste plastic supply port 11h. In the apparatus shown in FIG. 2, the cracked gas thermally decomposed in the pyrolysis tank 11a is sent to the reflux tower 14, which is one of the cooling and separation devices, via the tank top lines 21a and 21b. In the reflux tower 14, a reflux occurs inside, that is, the ascending cracked gas and the descending liquefied cracked gas flow in countercurrent. The inside of the reflux tower 14 may be filled with a packing material as necessary. By using the packing material, it is possible to set the height of the reflux tower low and reduce the degree of cooling.

[0028] The packing may be structured packing or irregular packing. Structured packing is preferable because it can keep the reflux state constant and can further reduce pressure loss. Examples of structured packing include mesh bodies processed into a cylindrical or tower shape. The structured packing is used with a diameter and height that match those of the reflux tower 14. Examples of such structured packing include MC Pack (manufactured by Matsui Machine Co., Ltd.).

[0029] The temperature at the top of the reflux tower 14 is preferably maintained at a temperature at which the reclaimed oil obtained in the present invention can be maintained in a gaseous state, specifically, at about 250°C.

[0030] The cracked gas flowing up from the pyrolysis vessel 11a to the reflux tower 14 contains not only the gasified recycled oil, which is the main component, but also high-boiling components such as insufficiently cracked wax that is liquid at room temperature. Due to the reflux in the reflux tower 14, the high-boiling components move back and forth within the reflux tower 14 and between the reflux tower 14 and the pyrolysis vessel 11a below. On the other hand, the higher the temperature is in the reflux tower 14, the less the high boiling point components are present, and the gas components are present almost exclusively near the top of the tower. This gas component (hereinafter sometimes referred to as "top gas") is sent from the top of the reflux tower 14 through the first recovery line 22 to the first product oil tank 15.

[0031] 1(a) and 2, two lines are shown: the top line 21a for ascending and the top line 21b for descending. The top line 21a is connected to the lower side of the reflux tower 14, while the top line 21b is connected to the bottom of the reflux tower 14. In the early stage of reflux in the reflux tower 14, the rise of the cracked gas due to the heating of the pyrolysis tank 11a becomes dominant, and the cracked gas rises in both lines. Next, as the rise of the cracked gas progresses and the reflux in the reflux tower 14 becomes active, the bottom of the reflux tower 14 becomes dominated by the descent of the liquefied material generated by the reflux rather than the rise of the cracked gas. Therefore, the top line 21b naturally becomes a descending line, and the top line 21a becomes an ascending line. The pot top line 21a and the pot top line 21b may be a single pipe extending from the bottom of the reflux tower 14 to the pyrolysis pot 11a. In this case, it is preferable to use a pipe of a certain thickness in accordance with the size of the pyrolysis pot 11a so that both the rise of the cracked gas and the liquefied material can smoothly flow in the pipe.

[0032] The gas component (top gas) discharged from the top of the reflux tower 14 to the first recovery line 22 is cooled on the way from the first recovery line 22 to the first product oil tank 15, and a liquefied component (recycled oil) is generated. This recycled oil includes components with a relatively high boiling point such as heavy oil (boiling point: 150°C to 250°C) and components such as light oil (boiling point: 100°C to 200°C) whose boiling point has been lowered due to decomposition. It also includes gas components that have been further decomposed and are not liquefied. In this first product oil tank 15, the components sent are left to stand and naturally cooled. In addition, the liquid component (recycled oil) liquefied in the first product oil tank is sent to the cooler 15a and cooled, and then returned to the first recovery line 22 using the first return line 31 and circulated and cooled. This cools the components sent to the first product oil tank.

[0033] Furthermore, as described later, a portion of the light oil obtained by the waste plastic oil treatment device of the present invention is sent to the first product oil tank 15 via the first return line 31 using the fifth return line 35. At this time, since the liquid temperature in the first product oil tank 15 is higher than the boiling point of the light oil, gasification of the sent light oil occurs, and in addition, gasification of the components corresponding to the light oil in the regenerated oil in the first product oil tank 15 is promoted. And, in accordance with this, the liquefied components among the components in the first product oil tank 15 are further cooled. From these, the group of devices constituting the first product oil tank 15, the cooler 15a, the circulation line from this cooler 15a to the first product oil tank 15 via the first return line 31, and the line that sends the light oil to the first return line 31 via the fifth return line 35 can be collectively said to be a cooling and separation device for the first product oil tank 15. The components gasified in this cooling separation device and the gas components that were not liquefied from the beginning in the first product oil tank 15 (hereinafter, these may be collectively referred to as "separated gas") are sent to the next process via the second recovery line 23. In this way, liquefied reclaimed oil (hereinafter, referred to as "first reclaimed oil") accumulates in the first product oil tank 15. This first reclaimed oil is mainly composed of heavy oil, with small amounts of components with lower boiling points such as light oil being mixed in. The content of light oil in this first reclaimed oil is approximately 3 to 8% by weight.

[0034] The first recycled oil in the first refined oil tank 15 is cooled in a cooler 15a by a pump and sent as heavy oil to the heavy oil tank 17 via a third recovery line 24. The heavy oil sent to the heavy oil tank 17 is sent to the outside as a product and used. Also, as described later, a part of the heavy oil in the heavy oil tank 17 can be used as fuel for the oil burner 11e. The liquid temperature in the first refined oil tank 15 is about 50°C to 80°C, and the liquid temperature in the heavy oil tank 17 is about 25°C to 40°C.

[0035] However, depending on the temperature of the overhead gas coming out of the upper part of the reflux tower 14, there is a risk that the reflux inside the reflux tower 14 is not sufficiently performed, and the high boiling point components to be refluxed may exit from the top of the reflux tower 14 to the first recovery line 22. As a means for preventing this, a part of the heavy oil in the heavy oil tank 17 may be returned to the upper part of the reflux tower 14 using the second return line 32. By returning the heavy oil in the heavy oil tank 17 to the upper part of the reflux tower 14, the temperature of the upper part of the reflux tower 14 can be lowered, so that the reflux inside the reflux tower 14 can be sufficiently performed. Furthermore, a part of the returned heavy oil can be returned to the thermal cracking vessel 11a and further thermally cracked to be converted into light oil.

[0036] Next, the gas components (separated gas) coming out of the first product oil tank 15 are sent to a condenser for condensing them. Either one condenser is provided, or multiple condensers are provided in series so that the gas components not liquefied in one condenser are fed to the next condenser. When one condenser is provided, the gas components not liquefied in that condenser, or when multiple condensers are provided in series, the gas components not liquefied in the last condenser, can be used as fuel for the gas burner 11f. A specific example in which two condensers are arranged in series will be described with reference to FIG.

[0037] The separated gas coming out of the first product oil tank 15 is cooled in the condenser 13a, which is one of the cooling and separating devices, through the second recovery line 23, and the liquefied liquid component is sent to the second product oil tank 16 through the second recovery line 23'. The gas component that was not condensed in the condenser 13a (hereinafter, sometimes referred to as the "first uncondensed gas") is further cooled in the condenser 13b, which is one of the cooling and separating devices, through the fourth recovery line 25, and separated into a liquefied liquid component and a gaseous gas component. The liquefied liquid component is sent to the second product oil tank 16 through the fifth recovery line 26. The liquid component sent to this second product oil tank 16, i.e., the reclaimed oil (hereinafter, referred to as the "second reclaimed oil"), has a lower boiling point than the first reclaimed oil, and is mainly light oil. A part of this second regenerated oil is returned to the second recovery line 23 before the condenser 13a via the third return line 33, lowering the temperature of the components in this second recovery line 23 and assisting the cooling in the condenser 13a. In addition, a part of the second regenerated oil sent to the second product oil tank 16 is returned to the fifth recovery line 26 via the fourth return line 34, circulating the second regenerated oil in the second product oil tank 16 and equalizing the temperature of the second regenerated oil in the second product oil tank 16. The remainder of the second regenerated oil sent to the second product oil tank 16 is sent to the light oil tank 18 via the sixth recovery line 27, and is sent to the outside as a product for use. In addition, a portion of the second recycled oil in the light oil tank 18 is returned to the first return line 31 via the fifth return line 35, merges with the first recovery line 22, and is sent to the first product oil tank 15, promoting separation and recovery of the light oil from the first recycled oil in the first product oil tank 15, as described above. The liquid temperature in the second refined oil tank 16 is about 25°C to 35°C, and the liquid temperature in the light oil tank 18 is about 25°C to 35°C. In addition, the gas components that are not condensed in the condenser 13b (hereinafter, sometimes referred to as the "second uncondensed gas") are gases that do not liquefy at room temperature, and are therefore released into the atmosphere as exhaust gas (the release line is not shown). However, as described below, they can be used as fuel gas for the gas burner 11f.

[0038] [Oil burner, gas burner] The pyrolysis vessel 11a is heated by a heating section 11b disposed around the vessel. Examples of heating means for heating the heating section 11b include an oil burner 11e and a gas burner 11f. The fuel oil for this oil burner 11e can be introduced from the outside, but if recycled oil such as heavy oil or light oil obtained by the waste plastic oil treatment device of the present invention is used, the use of external fuel can be reduced, and fuel efficiency can be improved. When heavy oil is used, as shown in Figure 2, heavy oil can be supplied as fuel to the oil burner 11e from the heavy oil tank 17 via the oil burner fuel line 38. When light oil is used, although not shown in Figure 2, a fuel line for the oil burner is formed from the light oil tank 18, and light oil can be supplied as fuel to the oil burner 11e via this line.

[0039] In addition, the fuel gas for the gas burner 11f can be introduced from the outside, but in the waste plastic oil treatment device of the present invention, if the gas components that were not liquefied in the cooling and separating device are used, the amount of external fuel used can be limited, and the fuel efficiency can be improved. As the gas components that were not liquefied in the cooling and separating device, gas components such as the separated gas, the first uncondensed gas, and the second uncondensed gas can be used. Among them, the second uncondensed gas has a low molecular weight and does not liquefy at room temperature, so it is a gas to be discharged into the atmosphere. It is preferable to burn this second uncondensed gas with a gas burner and use it to heat the pyrolysis furnace, since it is possible to effectively use the gas components to be discharged produced in the device itself, rather than using external fuel. One method for using this second uncondensed gas is to supply it as fuel for the gas burner 11f via the gas burner fuel line 39.

[0040] [Fractional distillation device] In the waste plastic oil treatment device according to the present invention, two types of recycled oil, heavy oil and light oil, are obtained, but the components of the light oil tend to remain in the heavy oil without being separated. As a method for separating the light oil from the heavy oil and increasing the amount of light oil recovered, a fractionation device 41 can be provided in the middle of the first recovery line 22 from the reflux tower 14 to the first refined oil tank 15, as shown in FIG. 3.

[0041] A portion of the first reclaimed oil from the first refined oil tank 15 that has been cooled in a cooler 15 a is introduced into the fractionation device 41 via a fractionation device introduction line 42 . Specifically, as shown in FIG. 4, the first recovery line 22 is attached to an upper portion such as the top of the fractionator 41, and the overhead gas in the first recovery line 22 is introduced into the fractionator 41 from an upper portion such as the top. In addition, the fractionator introduction line 42 is introduced from the side of the fractionator 41, and an outlet is formed in an upward direction near the center inside the fractionator 41. A spray nozzle 46 can be attached to the tip of this fractionator introduction line 42. As a result, the first recycled oil from the fractionator introduction line 42 blows upward in the fractionator 41 in a mist or shower shape (a state in which the flow is diffused), and flows counter to the overhead gas blown down from the top of the fractionator 41. As a result, the overhead gas introduced into the fractionator 41 is cooled by the first recycled oil, promoting the liquefaction of the heavy oil component of the overhead gas. The liquefied components are sent from a lower portion, such as the lowest portion, of the fractionation device 41 through the first recovery line 22' to the first product oil tank 15. The components sent to the first product oil tank 15 are discharged in the same manner as described above, except for the components sent to the fractionation device inlet line 42. Furthermore, the gas components that were not liquefied in the fractionation device 41 are discharged from a gas outlet 43 provided on the side of the fractionation device 41 near the middle to lower stages, pass through a gas discharge line 44, enter the second recovery line 23, and are combined with the separated gas from the first product oil tank 15 and sent to the condenser. If there is one condenser, the gas components are sent to that condenser, and if there are multiple condensers arranged in series, the gas components are sent to the first condenser (condenser 13a in FIG. 2). By using this fractionation device 41, it is possible to reduce the temperature of the first product oil tank 15 from a high temperature of approximately 150°C to around 40°C, which leads to improved safety around the first product oil tank and more stable operation.

[0042] In addition, a part of the light oil in the light oil tank 18 may be introduced into the first recycled oil in the fractionator introduction line 42 via the light oil supply line 45 and introduced into the fractionator 41. When the light oil is added to the first recycled oil and introduced into the fractionator 41, the added light oil takes heat from the overhead gas and causes gasification, and the liquefaction by cooling the overhead gas can be promoted. In addition, the components of the overhead gas that are not liquefied in the fractionator 41 are discharged from the gas outlet 43 together with the gas generated by the gasification of the light oil, so that the amount of the components of the overhead gas that are not liquefied that are taken in the components liquefied in the fractionator 41 is reduced, and the amount of the components that are not liquefied that are sent to the first product oil tank 15 can be reduced. For these reasons, the fractionation device 41 plays a part as a cooling and separating device for the first product oil tank 15.

[0043] [Extruder for transporting pyrolysis residue] The pyrolysis residue generated in the pyrolysis vessel 11a can be extracted by any method. It can be discharged to the outside from the extraction port 11j. As an example of this discharge method, as shown in FIG. 3, it can be sent to a pyrolysis residue transfer extruder 51 connected to the extraction port 11j and collected in a pyrolysis residue recovery tank 51b. This pyrolysis residue transfer extruder 51 is a device having an extruder body and a rotary motor 51a, and the pyrolysis residue is sent to the pyrolysis residue recovery tank 51b.

[0044] When removing the pyrolysis residue generated in the pyrolysis vessel 11a, a pyrolysis residue removal process is performed. First, the input of the raw waste plastic is stopped. After that, the pyrolysis vessel 11a is heated to promote fluidization of the pyrolysis residue together with the surrounding molten waste plastic. The temperature to which the temperature is raised is preferably 480°C or higher, and more preferably 490°C or higher. Also, it is preferably 500°C or lower. By setting the temperature within this range, the fluidity of the pyrolysis residue and the surrounding molten waste plastic can be improved, making it easier to move them. On the other hand, if the temperature is lower than this range, pyrolysis residue that is difficult to fluidize may be generated, making it difficult to move the pyrolysis residue sufficiently. Furthermore, if the temperature is higher than this range, carbonization of the pyrolysis residue may progress, and the amount of pyrolysis residue that is difficult to flow may increase. Note that this temperature rise further promotes the pyrolysis of the raw waste plastic, so the amount of non-pyrolyzed waste plastic remaining in the pyrolysis vessel 11a at the time of temperature rise is significantly reduced. Next, the mixture is moved to the periphery of the bottom 11g of the pyrolysis tank 11a by the agitator 11c, and fed from the discharge port 11j to one end of the pyrolysis residue transferring extruder 51. Next, the rotary motor 51a rotates the screw inside the pyrolysis residue transferring extruder 51, and the pyrolysis residue is fed to the other end of the pyrolysis residue transferring extruder 51. At this time, the pyrolysis residue is cooled by a cooling section (not shown). Then, the pyrolysis residue is sent to a pyrolysis residue recovery tank 51b connected to the other end of the pyrolysis residue transferring extruder 51. In this pyrolysis residue transporting extruder 51, the temperature of the pyrolysis residue is preferably cooled to about 180 to 250° C. If the temperature is too low, the contents may solidify and cause clogging, whereas if the temperature is too high, the pyrolysis residue may ignite.

[0045] The rotary motor 51a of the extruder 51 for transferring pyrolysis residue is provided at the other end opposite to one end of the extruder 51 for transferring pyrolysis residue, into which the pyrolysis residue is fed. Therefore, the seal portion between the main body of the extruder 51 for transferring pyrolysis residue having the screw and the rotary motor 51a, i.e., the seal portion provided at the portion where the shaft of the screw or the connecting portion between the shaft and the rotary motor 51a passes through the end face of the main body of the extruder 51 for transferring pyrolysis residue, is provided on the end face on the other end side of the extruder 51 for transferring pyrolysis residue.

[0046] The pyrolysis residue fed from one end of the pyrolysis residue transporting extruder 51 is heated and in a high temperature state as described above. In addition, the pyrolysis residue may be accompanied by surrounding molten waste plastics, and gas components may be generated. In such a state, if the rotary motor 51a is located on one end side of the pyrolysis residue transporting extruder 51, the seal portion will be present on the end face on the one end side of the pyrolysis residue transporting extruder 51. In this case, the high-temperature gas components and pyrolysis residue may come into contact with the seal portion, causing deformation of the seal portion, and these may leak from the seal portion. Since these leaking materials are high temperature, if leakage occurs, it is not favorable for the safety and conservation of equipment and people around the leakage location.

[0047] In contrast, in the present invention, since the rotary motor 51a is provided at the other end of the pyrolysis residue transporting extruder 51, the pyrolysis residue produced is sent to the pyrolysis residue recovery tank 51b on the outlet side, and the gas components produced are also sent to the pyrolysis residue recovery tank 51b on the outlet side together with the pyrolysis residue. At this time, the pyrolysis residue and gas components produced are cooled as they move inside the pyrolysis residue transporting extruder 51, and the temperature drops, which causes deformation or the like in the seal portion on the outlet side, reducing the risk of leakage from here. Furthermore, the pyrolysis residue and gas components are sent to the pyrolysis residue recovery tank 51b on the outlet side, and the location of the pyrolysis residue transfer extruder 51 connected to this pyrolysis residue recovery tank 51b is located just before the other end face of the pyrolysis residue transfer extruder 51, that is, the other end side (other end) of the pyrolysis residue transfer extruder 51, between the other end face where the seal portion is provided and the location where the pyrolysis residue is sent into the pyrolysis residue transfer extruder 51. This can further reduce the possibility that the pyrolysis residue sent out will come into contact with the seal portion. As a result, the pyrolysis residue is less likely to leak, and the safety of equipment and personnel can be ensured. EXAMPLES

[0048] The present invention will now be described more specifically with reference to examples. [Example 1] (Pyrolysis process of waste plastics) Waste plastic was oil-recovery treated using a waste plastic oil-recovery treatment device having a pyrolysis furnace 11 shown in FIG. 1(a), a raw material input extruder 12a, a raw material input heating line 12e, a pyrolysis residue transport extruder 51 shown in FIG. 3, and each device and line shown in FIG. 2. First, waste plastic (polyethylene: 100% by weight) was washed with water in a washing device (Bun-Sen, manufactured by Kanemiya Co., Ltd.) to remove dirt. Next, hot air of 70°C to 80°C was obtained by utilizing the exhaust heat from the pyrolysis furnace 11a, and this was blown onto the waste plastic to dry it.

[0049] Next, the mixture was fed into the raw material feeding extruder 12a at a rate of about 100 kg / h. The temperature condition of this raw material feeding extruder 12a (single screw extruder) was set so that the temperature on the outlet side was about 260°C. The molten waste plastics melted in the extruder body 12b of the extruder 12a are sent to the raw material input heating line 12e. The raw material input heating line 12e has an inclined portion inclined at 45° upward, and the temperature condition is set so that the outlet side is about 330°C. The molten waste plastics heated to about 330°C are continuously supplied to the pyrolysis vessel 11a. At this time, the raw material input extruder 12a and the heating portion 12c of the raw material input heating line 12e were maintained at a predetermined temperature by heating with an external fuel at the beginning of operation, but after the continuous operation of the waste plastic oil treatment device became stable, they were heated using the exhaust gas generated by the oil burner 11e and the gas burner 11f (the temperature of the exhaust gas was about 850°C for the exhaust gas from the oil burner 11e and about 850°C for the exhaust gas from the gas burner 11f). As a result, it was confirmed that it is possible to stably raise the temperature to the set temperature at each outlet of the raw material input extruder 12a and the raw material input heating line 12e, whether using one of these exhaust gases or using both exhaust gases in combination.

[0050] The pyrolysis vessel 11a of the pyrolysis furnace 11 had an inner diameter of 1 m, a height of 1.2 m, a cylindrical central portion, and a flat bottom portion using a dish-shaped flat head plate as shown in FIG. 1(a). A heating unit 11b was arranged on the outer periphery of the pyrolysis vessel 11a, and the pyrolysis vessel 11a was heated by this. The pyrolysis vessel 11a was adjusted so that the internal temperature was within the range of 400°C to 440°C. The heating unit 11b was heated using an oil burner 11e or a gas burner 11f. At the beginning of operation, an external fuel was used as fuel, but after the continuous operation of the waste plastic oil treatment device became stable, heavy oil obtained in the waste plastic oil treatment device and the second uncondensed gas that was not condensed in the condenser 13b were used as fuel. As a result, the pyrolysis vessel 11a was able to maintain the required internal temperature whether using either the oil burner 11e or the gas burner 11f or using both of them.

[0051] In the pyrolysis tank 11a, the molten waste plastic was pyrolyzed to become decomposed gas, which was transferred to the reflux tower 14 above the pyrolysis tank 11a. The reflux tower 14 had an inner diameter of 314 mm and a height of 3750 mm, and was filled with structured packing (MC Pack, manufactured by Matsui Machine Co., Ltd.). Inside this reflux tower 14, part of the cracked gas liquefied at the top, creating a reflux state. This is because the cracked gas cools and its temperature decreases as it moves toward the top of the reflux tower 14, and because, as will be described later, part of the heavy oil stored in the heavy oil tank 17 was supplied to the top of the reflux tower 14 and brought into direct contact with the cracked gas. The liquefied liquid of the cracked gas liquefied in the reflux tower 14 was returned to the thermal cracking tank 11a via the tank top line 21 (21b) and was again supplied to thermal cracking. On the other hand, the cracked gas (tower top gas) that was not liquefied was sent from the top of the reflux tower 14 to the first product oil tank 15 via the first recovery line 22. Then, a part of the liquid component (first recycled oil) sent to this first product oil tank 15 was cooled in the cooler 15a and returned to the first product oil tank 15 via the first return line 31 and used for circulating cooling. In addition, a part of the light oil from the light oil tank 18 described later was sent to this first return line 31 via the fifth return line 35. At this time, the light oil sent was gasified by taking heat from the first recycled oil, and the first recycled oil was cooled. In addition, since the component corresponding to the light oil contained in the first recycled oil was gasified, the light oil component was reduced from the heavy oil. These cooled the first reclaimed oil in the first refined oil tank 15.

[0052] The amount of regenerated oil sent from the reflux tower 14 to the first product oil tank 15 was 75 kg / h, the temperature of the first regenerated oil in the first product oil tank 15 was about 45° C., and the content of heavy oil in the first regenerated oil was about 20% by weight. A part of the first regenerated oil in the first product oil tank 15 was cooled in a cooler 15a, sent to a heavy oil tank 17, stored, and used as a product. In addition, a part of the heavy oil sent to the heavy oil tank 17 was used as fuel for the oil burner 11e or sent to the reflux tower 14. The liquid temperature in the heavy oil tank 17 was about 40°C.

[0053] The separated gas that was not liquefied in the first product oil tank 15 was sent to the condenser 13a and cooled. Water was used as the coolant at this time. After passing through the condenser 13a, the water used as the coolant became 40.6°C, so it was cooled in a cooling tower. The separated gas cooled by the condenser 13a was separated into gas and liquid, of which the liquid component was sent to the second product oil tank 16 as the second regenerated oil. A part of the sent second regenerated oil was returned to the second product oil tank 16, and the temperature of the regenerated oil in the second product oil tank 16 was made uniform, and circulatory cooling was performed. The temperature of the second regenerated oil in this second product oil tank 16 was about 35 ° C. A part of the second regenerated oil in this second product oil tank 16 was returned to the second recovery line 23 before the condenser 13a, cooled again, and subjected to gas-liquid separation. Furthermore, a part of the second regenerated oil was sent to the light oil tank 18 and used as a product. As a result, as described above, it was possible to reduce the light oil component held in the first regenerated oil in the first product tank 15. The liquid temperature in the light oil tank 18 was about 35°C.

[0054] The first uncondensed gas that was not condensed by the cooling in the condenser 13a was sent to the condenser 13b where it was further cooled and separated into gas and liquid. The obtained liquid component was sent to the second refined oil tank 16 as the second recycled oil, and the recovered second uncondensed gas was used as fuel for the gas burner.

[0055] (Pyrolysis residue removal process) After the above-mentioned process of thermal decomposition of waste plastic was carried out for about 20 hours, the introduction of waste plastic was stopped and the temperature inside the vessel was raised to about 480° C. to 500° C. At this time, heating was performed using only the oil burner 11e, only the gas burner 11f, or both the oil burner 11e and the gas burner 11f. In each case, the pyrolysis vessel 11a was able to maintain the required internal temperature. Then, the pyrolysis residue was fluidized and sent to the bottom periphery of the pyrolysis tank 11a by the agitator 11c. Then, it was extracted from the extraction port 11j at 80 kg / h for 10 minutes and sent to one end of the pyrolysis residue transfer extruder 51. The extracted pyrolysis residue was at a high temperature of about 450°C, but was cooled by a cooling section (not shown) while passing through the main body of the pyrolysis residue transfer extruder 51 to about 100°C, and was sent from the other end of the pyrolysis residue transfer extruder 51 to the pyrolysis residue recovery tank 51b. At this time, the temperature of the cooling section was adjusted so that the temperature of the pyrolysis residue sent to the pyrolysis residue recovery tank 51b was within the range of 80°C to 130°C. In addition, the rotary motor 51a of the extruder 51 for transferring pyrolysis residue was positioned at the other end opposite the end into which the pyrolysis residue was fed, so that the temperature of the pyrolysis residue was lowered to approximately 100°C. Furthermore, the position from which the pyrolysis residue was fed into the pyrolysis residue recovery tank 51b was the other end of the main body of the extruder 51 for transferring pyrolysis residue, and was positioned between the other end face where the seal portion was provided and the one end into which the pyrolysis residue was fed, so that the pyrolysis residue could be prevented from coming into contact with the seal portion, no deformation of the seal portion occurred, and no leakage of the pyrolysis residue occurred. Furthermore, the gas components contained in the pyrolysis residue passing through the main body of the extruder 51 for transporting pyrolysis residue are sent to the pyrolysis residue recovery tank 51b together with the pyrolysis residue, and are discharged from the vent in the extruder 51 for transporting pyrolysis residue by regular nitrogen purging. Therefore, the gas components do not cause deformation of the seal, and no leakage of the pyrolysis residue occurs.

[0056] As a result of such an experiment, it was found that adhesion of pyrolysis residues in the pyrolysis vessel 11a could be significantly reduced. Furthermore, it was found that the temperature of the pyrolysis vessel 11a, the raw material input extruder 12a, and the raw material input heating line 12e could be adjusted, and the heavy oil and gas components obtained in the waste plastic oil treatment device could be effectively utilized. Furthermore, it was found that cooling of the pyrolysis vessel 11a was not required in the pyrolysis residue removal process, and that there was no need to heat it up to the required temperature again when restarting pyrolysis, improving thermal efficiency.

[0057] [Example 2] In Example 1, the fractionating device 41 shown in FIG. 4 was incorporated, and an experiment was carried out using the waste plastic oil-recovery treatment device shown in FIG. The overhead gas from the top of the reflux tower 14 is fed into the top of the fractionator 41, and a portion of the first recycled oil in the first product oil tank 15 is cooled in a cooler 15a, and this liquid is mixed with a portion of the light oil in the light oil tank 18. The mixture is then blown upward in a shower-like manner, i.e., with the flow diffused, inside the fractionator 41 via the fractionator inlet line 42 and a spray nozzle 46 attached to the outlet tip of the fractionator inlet line 42. As a result, in the fractionation unit 41, the heat of the cracked gas from the top of the reflux tower 14 contributed to the gasification of the light oil from the light oil tank 18, promoting the gasification of the components corresponding to the light oil, and the separated gas was discharged from the gas discharge line 44. Furthermore, the cooling and liquefaction of the components corresponding to the heavy oil in the overhead gas was promoted. The liquefied product was then sent from the bottom of the fractionation unit 41 to the first product oil tank 15. As a result, the temperature of the first recycled oil sent to the first refined oil tank 15 was lower than in Example 1, and as a result, the light oil-containing components in the heavy oil sent to the heavy oil tank 17 were reduced by approximately 3 to 8%. In this Example 2, the liquid temperature in the first product oil tank 15 was approximately 40°C, the liquid temperature in the heavy oil tank 17 was approximately 40°C, the liquid temperature in the second product oil tank 16 was approximately 35°C, and the liquid temperature in the light oil tank 18 was approximately 35°C. In other respects, the same results as in Example 1 were obtained. [Explanation of symbols]

[0058] 11 Pyrolysis furnace 11a Pyrolysis kettle 11b Heating section 11c Mixer 11e Oil burner 11f Gas burner 11g bottom 11h Waste plastic supply port 11j Extraction port 11k stirring shaft 11m, 11n stirring blade 11p Stirring motor 11r Fins 12a Raw material input extruder 12b Extruder body 12c heating section 12d Inlet 12e Heating line for raw material input 12f heating section 12g fins 13, 13a, 13b Condenser 14 Reflux tower 15 No. 1 Produced Oil Tank 15a cooler 16 No. 2 Produced Oil Tank 17 Heavy Oil Tank 18 Light Oil Tank 21a, 21b Kamato Line 22, 22' First recovery line 23, 23' Second recovery line 24 3rd Collection Line 25 4th Collection Line 26 5th Recovery Line 27 6th Recovery Line 31 First Return Line 32 Second return line 33 Third Return Line 34 4th Return Line 35 5th return line 38 Fuel line for oil burner 39 Fuel line for gas burner 41 Fractionation equipment 42 Fractionation equipment introduction line 43 Gas exhaust port 44 Gas exhaust line 45 Light Oil Supply Line 46 Spray Nozzle 51 Extruder for transporting pyrolysis residue 51a Rotary motor 51b Pyrolysis residue recovery tank

Claims

1. This is an apparatus for waste plastic oil treatment, which has a pyrolysis tank that thermally decomposes waste plastic to generate decomposition gas, and a cooling and separation device that performs gas-liquid separation on the decomposition gas obtained in the pyrolysis tank multiple times to obtain liquid recycled oil, The method further comprises a raw material input extruder for heating and transporting the waste plastic, and a raw material input heating line for further heating the molten waste plastic melted and transported by the raw material input extruder and sending it to the pyrolysis kettle, The raw material input heating line has a heating section that raises the temperature of the waste plastic above the thermal decomposition temperature, and also has an upwardly inclined section from the raw material input extruder to the waste plastic supply port of the thermal decomposition tank.

2. The cooling and separation device is a device that separates the liquid recycled oil and the gas component by cooling, A heating unit for heating the pyrolysis vessel is provided on the outer periphery of the pyrolysis vessel, 2. The waste plastic oil-recovery treatment apparatus according to claim 1, wherein the heating means of the heating unit is at least one selected from the group consisting of an oil burner that uses the recycled oil as fuel and a gas burner that uses the gas component as fuel.

3. The raw material input extruder has a heating section for heating waste plastics, 3. The waste plastic oil treatment apparatus according to claim 2, wherein the heating means for heating at least one of the heating section of the raw material input extruder and the heating section of the raw material input heating line is the exhaust gas of the oil burner and the exhaust gas of the gas burner.

4. This method for producing recycled oil comprises pyrolyzing waste plastic in a pyrolysis vessel to generate a decomposition gas, and then subjecting the decomposition gas obtained in the pyrolysis vessel to gas-liquid separation multiple times using a cooling separation device to obtain a liquid recycled oil. The waste plastic is heated and transported to the pyrolysis furnace by a raw material input extruder and a raw material input heating line, The waste plastic is heated and melted by the raw material input extruder and transported to the raw material input heating line, The molten waste plastic is further heated by the raw material input heating line and sent to the pyrolysis furnace, The raw material input heating line has a heating section that raises the temperature of the waste plastic above the thermal decomposition temperature, and has an upwardly inclined section from the raw material input extruder to the waste plastic supply port of the thermal decomposition tank.

5. The liquid recycled oil and the gaseous gas components are separated by cooling in the cooling and separation device, A heating unit for heating the pyrolysis vessel is provided on the outer periphery of the pyrolysis vessel, The method for producing recycled oil according to claim 4, wherein the heating section is heated by at least one selected from an oil burner that uses the recycled oil as fuel and a gas burner that uses the gas component as fuel.

6. The raw material input extruder is provided with a heating section for heating waste plastics, The method for producing recycled oil according to claim 5, wherein at least one of the heating section of the raw material input extruder and the heating section of the raw material input heating line is heated by the exhaust gas of the oil burner and the exhaust gas of the gas burner.

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