JP2009242751A - Manufacturing method and apparatus for waste plastic oil slurry - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a waste plastic oil slurry having a high waste plastic content, securely at low cost in a short time. <P>SOLUTION: A manufacturing method for waste plastic oil slurry comprises dissolving a waste plastic (b) in a solvent (a) to convert it into oil slurry. In the procedure in which the solvent (a) is heated to a preset temperature whilst stirring, a constant amount of the waste plastic (b) is dissolved in the solvent (a) in small portions by several times to dozens of times. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for producing waste plastic oil slurry for effectively using plastic waste.

  In recent years, a large amount of plastic has been discarded as industrial waste or general waste, and its disposal has become a social problem. As disposal methods of this waste plastic, landfilling, incineration, thermal recycling, and material recycling are known.

  In the landfill, not only the active ingredient is not recovered, but also the plastic has a low bulk density, so that a large landfill site is required. Moreover, it is not preferable from an environmental viewpoint.

  Incineration of plastic generates high heat, so it is easy to damage the incinerator. There are also the generation of harmful substances such as NOx.

  Thermal recycling is a method of converting waste plastic into oil or gas and using it as fuel. For example, Patent Document 1 discloses a method of hydrocracking waste plastic at high temperature and high pressure to make light oil. Yes.

  There are two types of material recycling: recycling plastic waste and changing it to other useful chemicals (chemical recycling). In the latter case, for example, in Patent Document 2, waste plastic is heated together with coal tar and the like at high temperature. A method of recovering benzene, toluene, xylene (BTX) by hydrocracking under high pressure and then reacting the reaction product in the presence of a cyclization catalyst is disclosed.

  As described above, when performing thermal recycling or chemical recycling, as a pretreatment method of waste plastic, for example, there is a method of mixing waste plastic with oil such as heavy oil to make a slurry. There has been proposed a method in which a finely pulverized powder is formed (for example, 200 microns or less), and this waste plastic powder is mixed with oil such as heavy oil to form a slurry (see, for example, Patent Document 3).

However, in order to finely pulverize the waste plastic to 200 microns or less, a special method such as freeze pulverization is required, which causes a problem that the pulverization cost becomes very high. Moreover, since waste plastic has a low density, it is not easily mixed with oil such as heavy oil, and its slurry is not easy. Further, since the density of the waste plastic is low, when the slurry concentration is increased, there is a problem that the waste plastic slurry loses fluidization and cannot be pumped. Waste plastic slurry obtained by simply mixing waste plastic powder with oil such as heavy oil can be pumped only when the slurry concentration is 20 wt% or less.
JP-A-5-186632 JP 2003-321682 A JP 2004-346107 A

  The present invention has been made to solve such problems, and one of its purposes is a high-temperature and high-pressure hydrogenation reactor (for example, a pressure of 5.0 to 1.5 MPa, a temperature of 350 to 480 ° C.). ) To provide a method for producing a waste plastic oil slurry capable of continuous and stable pumping.

  Another object of the present invention is to provide a method and apparatus for producing a waste plastic oil slurry that can reliably produce a waste plastic oil slurry having a high concentration of waste plastic at a low cost in a short time.

  The method for producing a waste plastic oil slurry according to claim 1 of the present application is a method for producing a waste plastic oil slurry in which waste plastic is dissolved in a solvent to form an oil slurry, and in the process of heating to a set temperature while stirring the solvent, A certain amount of waste plastic is divided into several to several tens of times and dissolved in a solvent.

  The method for producing a waste plastic oil slurry according to claim 2 of the present application is the method according to claim 1, wherein the solvent in the tank is subdivided into the solvent every time the solvent in the tank rises to 1 to 20 ° C. after being heated to a constant temperature. It is characterized by being introduced into

  The method for producing a waste plastic oil slurry according to claim 3 of the present application is characterized in that, in claim 1 or 2, the solvent is injected onto the waste plastic charged in the tank.

  The method for producing a waste plastic oil slurry according to claim 4 of the present application is the temperature rise control according to claim 1, wherein the solvent is heated to a temperature range in which most of the waste plastic is dissolved in the solvent and the waste plastic or solvent is not gasified. It is characterized by doing.

  The method for producing a waste plastic oil slurry according to claim 5 of the present application is characterized in that, in claim 1, the component vaporized during the dissolution of the waste plastic is condensed and returned to the solvent.

  The method for producing a waste plastic oil slurry according to claim 6 of the present application is the method according to claim 1, wherein the waste plastic is dissolved in a solvent to form an oil slurry, and then the oil slurry is supplied to a waste plastic slurry supply tank in a subsequent process. The oil slurry supplied to the waste plastic slurry supply tank is circulated between the waste plastic slurry supply tank and a circulation pipe provided outside the waste plastic slurry supply tank.

  A waste plastic oil slurry manufacturing apparatus according to claim 7 of the present application includes a slurry preparation tank, a stirrer for stirring the solvent in the tank, a waste plastic tank for supplying waste plastic into the tank, and a solvent temperature in the tank. And a valve in a waste plastic charging pipe connecting the slurry preparation tank and the waste plastic tank. After the temperature of the solvent in the tank has risen to a certain temperature, the valve is 1-20 ° C. Each time it rises, it opens and closes to supply a certain amount of waste plastic into the tank.

  The waste plastic oil slurry manufacturing apparatus according to claim 8 of the present application is the waste plastic oil slurry manufacturing apparatus according to claim 7, wherein the slurry preparation tank is formed by a covered cylindrical tank body and an inverted frustoconical tank constriction portion, and the stirring device is a tank. It is formed by a rotating shaft that passes through the lid of the main body and reaches the outlet of the tank throttle portion, and a stirring blade provided in multiple stages on the rotating shaft, and at least the uppermost stirring blade lowers the solution below the tank A function is provided, and the lowermost stirring blade is provided with a function of raising the solution upward of the tank.

  The waste plastic oil slurry manufacturing apparatus according to claim 9 of the present application is the waste plastic oil slurry manufacturing apparatus according to claim 7, wherein the waste plastic tank valve is opened and closed each time the solvent in the tank rises by 1 to 20 ° C, and a certain amount is placed in the tank. It is characterized by supplying waste plastic.

  The waste plastic oil slurry manufacturing apparatus according to claim 10 of the present application is characterized in that, in claim 7, a nozzle for injecting a solvent is provided in an upper part of the slurry preparation tank.

  The apparatus for producing a waste plastic oil slurry according to claim 11 of the present application is the light fraction recovery according to claim 7, wherein the vaporized components are condensed and returned to the slurry preparation tank at the upper part of the slurry preparation tank. A device is provided.

  A waste plastic oil slurry production apparatus according to claim 12 of the present application is the waste plastic oil slurry supply tank according to claim 7, wherein a waste plastic slurry supply tank is provided downstream of the slurry preparation tank, and the oil slurry produced in the slurry preparation tank is disposed of as waste plastic slurry. While supplying to a supply tank, the oil slurry in a waste plastic slurry supply tank is circulated between a waste plastic slurry supply tank and the circulation pipe provided in the exterior of this waste plastic slurry supply tank.

  The invention according to claim 1 of the present application is a method for producing a waste plastic oil slurry in which waste plastic is dissolved in a solvent to form an oil slurry. In the process of heating to a set temperature while stirring the solvent, a certain amount of waste plastic is added. Since it is dissolved in a solvent by dividing it into several to several tens of times, the mixing and dissolution of waste plastic with a low bulk density into the solvent is smoothly promoted, and the waste plastic oil slurry with a high waste plastic concentration is surely made inexpensive. It can be manufactured in a short time.

  In the invention according to claim 2 of the present application, since the waste plastic is put into the solvent every time the solvent in the tank rises to 1 to 20 ° C. after being heated to a certain temperature, the invention according to claim 1 In the same manner, the mixing and dissolution of the waste plastic into the solvent is smoothly promoted, and a waste plastic oil slurry having a high concentration of waste plastic can be reliably and inexpensively produced in a short time.

  In the invention according to claim 3 of the present application, since the solvent is sprayed onto the waste plastic introduced into the tank, the waste plastic having a low density gets wet with the solvent and becomes easily compatible with the solvent in the tank. Is easily dissolved in the solvent.

  In the invention according to claim 4 of the present application, since the temperature of the solvent is controlled to a temperature range in which most of the waste plastic is dissolved in the solvent and the waste plastic or solvent is not gasified, dissolution of the waste plastic is promoted. It is possible to reliably produce a waste plastic slurry having a high concentration of waste plastic at a low cost in a short time, and to prevent troubles due to gasification of the waste plastic and solvent (such as cavitation of the supply pump and slurry alteration).

  In the invention according to claim 5 of the present application, the components evaporated during the dissolution of the waste plastic are condensed and returned to the solvent, so that the initial composition of the waste plastic and the solvent in the waste plastic slurry can be maintained.

  In the invention according to claim 6 of the present application, after waste plastic is dissolved in a solvent to form an oil slurry, the oil slurry is supplied to a waste plastic slurry supply tank in a post-process and supplied to a waste plastic slurry supply tank. Since the oil slurry is circulated between the waste plastic slurry supply tank and a circulation pipe provided outside the waste plastic slurry supply tank, it is possible to prevent the generation of gums during storage, By applying a back pressure to continuous liquid feeding by the high-pressure slurry pump to the reactor and preventing separation of undissolved solids, more stable continuous liquid feeding is possible.

  The invention according to claim 7 of the present application includes: a stirring device for stirring the solvent in the tank to the slurry preparation tank; a waste plastic tank for supplying waste plastic into the tank; and a temperature sensor for measuring the solvent temperature in the tank; In addition, a valve is provided in a waste plastic charging pipe connecting the slurry preparation tank and the waste plastic tank, and the valve is opened and closed every time the temperature of the solvent in the tank rises to 1 to 20 ° C. Since a certain amount of waste plastic is supplied into the tank, waste plastic with a low bulk density and solvent are efficiently mixed and dissolution is promoted. Can be manufactured.

  The invention according to claim 8 of the present application is that the slurry preparation tank is formed by a covered cylindrical tank main body and an inverted frustoconical tank constriction section, and the stirring device passes through the tank main section lid section. The rotating shaft reaching the outlet of the rotating shaft and the stirring blades provided in multiple stages on the rotating shaft, and at least the uppermost stirring blade has a function of lowering the solution below the tank, and the lowermost stirring blade Has the function of raising the solution upward in the tank, so that the undissolved waste plastic can be quickly dissolved in the slurry preparation tank without being settled or suspended on the solvent surface.

  The invention according to claim 9 of the present application opens and closes the valve of the waste plastic tank each time the solvent in the tank rises by 1 to 20 ° C., and supplies a certain amount of waste plastic into the tank. A small portion can be supplied to the slurry preparation tank. Therefore, the waste plastic having a low bulk density and the solvent are efficiently mixed to promote dissolution, and a waste plastic oil slurry having a high waste plastic concentration can be reliably and inexpensively produced in a short time.

  In the invention according to claim 10 of the present application, since the nozzle for injecting the solvent is provided at the upper part of the slurry preparation tank, the waste plastic having a low density is wetted by the solvent dropped from the nozzle, so that it becomes easy to become familiar with the solvent in the tank. The waste plastic is easily dissolved in the solvent.

  In the invention according to claim 11 of the present application, the light fraction recovery device for condensing the vaporized component during the dissolution of the waste plastic and returning it to the slurry preparation tank is provided in the upper part of the slurry preparation tank. It is possible to prevent a decrease in the components that have been vaporized, and to maintain the initial composition of the waste plastic and the solvent in the waste plastic slurry.

  According to a twelfth aspect of the present invention, a waste plastic slurry supply tank is provided on the downstream side of the slurry preparation tank, and the oil slurry produced in the slurry preparation tank is supplied to the waste plastic slurry supply tank, and the waste plastic slurry supply tank is provided. The oil slurry inside is circulated between a waste plastic slurry supply tank and a circulation pipe provided outside the waste plastic slurry supply tank, so that generation of gum during storage is prevented and high-temperature and high-pressure hydrogenation reaction is performed. By applying a back pressure to the continuous liquid feeding of the high-pressure slurry pump to the vessel and preventing separation of undissolved solids, a more stable continuous liquid feeding becomes possible.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the waste plastic oil slurry production apparatus 1 includes a slurry preparation tank 2 and a waste plastic slurry supply tank 3 positioned on the downstream side thereof. The slurry preparation tank 2 includes a stirring device 4 that stirs the solvent a in the tank 2, a waste plastic tank 5 that supplies the waste plastic b into the tank 2, a temperature sensor 6 that measures the solvent temperature in the tank 2, An electric heater 7 for heating the tank 2 is provided.

  As the solvent, heavy oil such as tar oil or hydrogenated solvent is preferably used. In addition, a predetermined amount of Fe-based catalyst such as iron oxide or slag ore slag is mixed in the solvent.

  The waste plastic tank 5 is provided with a valve 9 in a waste plastic charging pipe 8 connecting the tank 5 and the slurry preparation tank 2, and the valve 9 is opened and closed by a control device 10 that operates based on an input signal from the temperature sensor 6. It comes to control.

  The controller 10 opens and closes the valve 9 of the waste plastic tank 5 every time the solvent a in the slurry preparation tank 2 rises to 1 to 20 ° C. While the temperature is increased to a temperature range (for example, 140 to 240 ° C., preferably 170 to 220 ° C.) where most of the waste plastic is dissolved in the solvent and the waste plastic or solvent is not gasified. In addition, the electric heater 7 is controlled.

  In addition, the temperature sensor 6 is installed between the position immediately below the solvent level and the center of the tank in order to easily measure the temperature drop of the solvent level caused by the dissolution of the waste plastic charged in the slurry preparation tank 2. It is important to do.

  The waste plastic is not particularly limited as long as it can generate a low-molecular hydrocarbon by a hydrocracking reaction, and most plastics and mixtures thereof are targeted. This is not limited to thermoplastic resins, but also includes thermosetting resins. The main object is a polyolefin resin such as polyethylene, polypropylene, polystyrene, and a mixture thereof, but polyvinyl chloride, polyvinylidene chloride, and the like may be mixed therein. The chlorine content in these chlorine-containing resins exhibits a catalytic action in hydrocracking, and a liquefied product with a higher light oil content is obtained.

  In the present invention, waste plastic crushed to a certain particle size (for example, 0.3 to 5 mm) obtained by crushing and treating waste plastic in general municipal waste can be applied as it is.

  The slurry preparation tank 2 is formed by a covered cylindrical tank main body 11 and an inverted frustoconical tank constriction part 12, and an outlet valve 14 is provided at the outlet 13 (lower end part) of the tank constriction part 12.

  The stirring device 4 is formed by a rotating shaft 16 that passes through the lid portion 15 of the tank body 11 and reaches the outlet 13 of the tank throttling portion 12, and a stirring blade group 17 provided on the rotating shaft 16 in multiple stages. Each agitation blade group 17 is formed by a plurality of agitation blades 18 provided radially on the rotary shaft 16, but the uppermost agitation blade 18a has an elevation angle α as shown in FIG. X is the rotation direction of the stirring blade), and at the same time the solution is stirred, the solution is allowed to flow downward along the rotating shaft 16. On the other hand, as shown in FIG. 3, the lowermost stirring blade 18b has a depression angle β, and simultaneously agitates the solution and pushes back the solution upward along the wall surface of the slurry preparation tank 2 so that undissolved waste plastic is removed from the tank. It is designed to prevent accumulation near the outlet.

  The angle of attack α of the uppermost stirring blade 18a is preferably in the range of 30 to 80 °. When the angle of attack α is less than 30 °, the stirring force is insufficient, and the force for causing the solution to flow downward along the rotating shaft 16 is also insufficient. On the other hand, when the angle of attack α exceeds 80 °, the stirring resistance of the stirring blade increases, but the force for causing the solution to flow downward along the rotating shaft 16 is insufficient.

  On the other hand, the depression angle β of the lowermost stirring blade 18b is preferably in the range of 30 to 80 °. When the depression angle β is less than 30 °, the stirring force is insufficient, and the force for pushing the solution upward along the wall surface of the slurry preparation tank 2 is also insufficient. Conversely, when the depression angle β exceeds 80 °, the stirring resistance of the stirring blade increases, but the force to push the solution upward along the wall surface of the slurry preparation tank 2 is insufficient. In addition, the stirring blade 18c located in an intermediate part should just be what can stir a solution, and a normal means may be sufficient as it.

  The rotating shaft 16 of the stirrer is rotated in a predetermined direction by the electric motor 7, and the rotation speed is preferably in the range of 10 to 500 rpm. When the rotational speed of the rotating shaft is less than 10 rpm, the stirring force of the stirring blade is increased when the rotational speed of the rotating shaft exceeds 500 rpm.

  The slurry preparation tank 2 is provided with a solvent injection nozzle 20 on the top plate, and the solvent a extracted from the solvent extraction pipe 21 provided in the tank throttle section 12 is sprayed onto the waste plastic using the solvent injection nozzle 20. It has become. The position of the solvent injection nozzle is such that the solvent injected from the solvent injection nozzle 20 is applied to the waste plastic dropped from the waste plastic injection pipe 8 so as to face the rotation direction of the stirring blade 18. It is desirable to be located downstream.

  In addition, a light fraction collection device 22 is provided in the upper part of the slurry preparation tank 2 so that components evaporated during the dissolution of the waste plastic are recondensed and returned to the slurry preparation tank 2. The light fraction collection device 22 is a kind of condenser, and supplies the cooling water c to the jacket portion 24 of the light fraction collection device 22 in the middle of the exhaust pipe 23 provided in the upper part of the slurry preparation tank 2. Thus, the inside of the recovery device 22 is rapidly cooled. Furthermore, the slurry preparation tank 2 includes a solvent supply pipe 26 having a valve 25 on the upper side surface.

  The slurry preparation tank 2 is connected to the top plate 31 of the waste plastic slurry supply tank 3 through a slurry supply pipe 30 connected to the outlet valve 14. The waste plastic supply tank 3 includes a stirrer 33 driven by an electric motor 32 and an electric heater 34 on a side surface thereof.

  Further, the waste plastic slurry supply tank 3 is provided with a circulation pipe 36 communicating with the outlet 35 at the bottom of the tank and the top plate 31 of the tank 3 outside, and the oil slurry d in the tank 3 is transferred to the waste plastic supply tank 3. It is circulated between a circulation pipe 36 provided outside the waste plastic supply tank 3. Further, the oil slurry d in the tank 3 is removed from the branch pipe 37 branched from the circulation pipe 36 by a high pressure slurry pump 40 (not shown) at a high temperature and high pressure hydrogenation reactor (pressure 5.0 to 1.5 MPa, temperature 350 to 480 ° C.) from the branch pipe 41.

  Here, the concentration (component) of the oil slurry is, for example, 10 to 40 wt% waste plastic, 0 to 10 wt% catalyst (Fe-based), and 50 to 90 wt% solvent (tar oil).

  The slurry supply pipe 30 is provided with a first slurry centrifugal pump (slurry transfer pump) 38, the circulation pipe 36 is provided with a second slurry centrifugal pump (slurry transfer pump) 39, and the branch pipe 37 is provided with A high-pressure slurry pump (reciprocating pump such as a plunger pump) 40 is provided.

  Next, the operation of the waste plastic oil slurry production apparatus will be described.

  When a predetermined amount of a solvent (for example, tar oil) a containing a catalyst (Fe-based) is supplied from the solvent supply pipe 26 to the slurry preparation tank 2, the electric heater 7 generates heat in response to a command from the control device 10. Thus, the solvent a in the tank 2 is heated to a certain temperature.

  When the solvent a reaches the first set temperature (for example, 150 ° C.), the control device 10 opens and closes the valve 9 of the waste plastic charging pipe 8 for a certain period of time. A certain amount of waste plastic b, which is a fraction of the total amount to a few tens of minutes, is put into the slurry preparation tank 2 and mixed with the solvent to be dissolved.

  The waste plastic thrown into the tank 2 is wetted by the solvent sprayed from the solvent spray nozzle 20, so that it becomes easy to become familiar with the solvent in the tank 2 and increases in weight. It becomes easy. Moreover, it is drawn into the solvent a in the tank 2 by the pulling force of the uppermost stirring blade 18a, and is easily dissolved.

  When the waste plastic b is put into the tank 2 and a part thereof is dissolved, the liquid surface temperature of the solvent in the tank 2 is slightly lowered (see FIG. 4), but is further heated and the solvent temperature in the tank 2 is changed to the first temperature. 2 When a set temperature (for example, 160 ° C.) is reached, the control device 10 opens and closes the valve 9 of the waste plastic charging pipe 8 again for a certain period of time, and during that time a small amount (for example, several minutes of the total charging volume) 1 to a few tens of minutes 1) a certain amount of waste plastic b is put into the slurry preparation tank 2 and mixed with a solvent to be dissolved.

  When the above-mentioned waste plastic charging operation is repeated and all of the preset waste plastic is charged, the solvent temperature in the tank 2 is maintained at a set value (for example, 150 to 240 ° C, preferably 170 to 220 ° C). Then, the tank 2 is stirred by the stirring device 4 to dissolve most of the waste plastic b in the solvent a.

  After completion of the waste plastic dissolving operation in the slurry preparation tank, the outlet valve 14 of the slurry preparation tank 2 is opened and the first slurry centrifugal pump 38 is driven to change the waste plastic oil slurry d in the slurry preparation tank 2 into the waste plastic slurry. The entire amount is transferred to the supply tank 3.

  After transferring the waste plastic oil slurry, the outlet valve 14 of the slurry preparation tank 2 is closed and the first slurry centrifugal pump 38 is stopped. Thereafter, in the slurry preparation tank 2, the melting operation of the waste plastic is restarted in the same manner.

  On the other hand, in the waste plastic slurry supply tank 3, the second slurry centrifugal pump 39 is operated while the waste plastic slurry d is held at the same set temperature as that in the tank 2 by the heater 34, and the waste plastic slurry supply tank 3 The waste plastic oil slurry d is constantly circulated between the tank 3 and the circulation pipe 36 outside the tank to prevent the generation of gum of the waste plastic oil slurry d and the high pressure slurry pump 40 is used to discard the waste plastic oil in the tank 3. Slurry d is continuously supplied at a constant flow rate to a high-temperature and high-pressure hydrogenation reactor (pressure 5.0 to 1.5 MPa, temperature 350 to 480 ° C.) not shown.

  Here, the circulation of the waste plastic slurry d between the tank 3 and the circulation pipe 36 outside the tank applies a back pressure to the high-pressure slurry pump and prevents the separation of the undissolved solids, thereby providing a stable supply. It is possible.

It is a schematic block diagram of the manufacturing apparatus of the waste plastic oil slurry which concerns on this invention. It is explanatory drawing of the elevation angle of the uppermost stirring blade. It is explanatory drawing of the depression angle of the lowermost stirring blade. It is a figure which shows the operating method of the manufacturing apparatus of the waste plastic oil slurry which concerns on this invention.

Explanation of symbols

a Solvent b Waste plastic d Oil slurry

Claims (12)

  In a method for producing a waste plastic oil slurry in which waste plastic is dissolved in a solvent to form an oil slurry, a certain amount of waste plastic is subdivided into several to several tens of times in the process of heating the solvent to a set temperature while stirring. A method for producing a waste plastic oil slurry, wherein the slurry is dissolved in a solvent.   2. The method for producing a waste plastic oil slurry according to claim 1, wherein each time the solvent in the tank rises to 1 to 20 [deg.] C. after raising the temperature to a certain temperature, a small amount of waste plastic is put into the solvent.   The method for producing a waste plastic oil slurry according to claim 1 or 2, wherein a solvent is sprayed onto the waste plastic charged in the tank.   2. The method for producing a waste plastic oil slurry according to claim 1, wherein the temperature of the solvent is controlled to a temperature range in which most of the waste plastic is dissolved in the solvent and the waste plastic or solvent is not gasified.   2. The method for producing a waste plastic oil slurry according to claim 1, wherein the component vaporized during the dissolution of the waste plastic is condensed and returned to the solvent.   After the waste plastic is dissolved in a solvent to form an oil slurry, the oil slurry is supplied to a waste plastic slurry supply tank in a post-process, and the oil slurry supplied to the waste plastic slurry supply tank is used as a waste plastic slurry supply tank. 2. The method for producing a waste plastic oil slurry according to claim 1, wherein the waste plastic slurry is circulated between a circulation pipe provided outside the waste plastic slurry supply tank.   The slurry preparation tank is provided with a stirring device for stirring the solvent in the tank, a waste plastic tank for supplying waste plastic into the tank, and a temperature sensor for measuring the temperature of the solvent in the tank, and the slurry preparation tank and the waste tank. A valve is provided in the waste plastic input pipe connecting the plastic tank, and the valve is opened and closed each time the solvent in the tank rises to 1 to 20 ° C after the temperature rises to a certain temperature, and a certain amount of the waste plastic in the tank An apparatus for producing a waste plastic oil slurry, characterized in that   The slurry preparation tank is formed by a covered cylindrical tank body and an inverted frustoconical tank squeezing part, and the agitation device passes through the lid part of the tank body and reaches the outlet of the tank squeezing part. The at least uppermost stirring blade has a function of lowering the solution below the tank, and the lowermost stirring blade has a function of raising the solution above the tank. The apparatus for producing a waste plastic oil slurry according to claim 7, wherein   8. The waste plastic oil slurry according to claim 7, wherein a certain amount of waste plastic is supplied into the tank by opening and closing a valve of the waste plastic tank each time the solvent in the tank rises by 1 to 20 ° C. Manufacturing equipment.   8. The apparatus for producing a waste plastic oil slurry according to claim 7, wherein a nozzle for injecting a solvent is provided in an upper part of the slurry preparation tank.   8. The apparatus for producing a waste plastic oil slurry according to claim 7, wherein a light fraction collecting device for condensing components evaporated during dissolution of the waste plastic and returning it to the slurry preparation tank is provided at an upper portion of the slurry preparation tank. .   A waste plastic slurry supply tank is provided on the downstream side of the slurry preparation tank. The oil slurry produced in the slurry preparation tank is supplied to the waste plastic slurry supply tank, and the oil slurry in the waste plastic slurry supply tank is used as the waste plastic slurry. The apparatus for producing a waste plastic oil slurry according to claim 7, wherein the waste plastic oil slurry is circulated between a supply tank and a circulation pipe provided outside the waste plastic slurry supply tank.