JP5004874B2 - Supply method of waste plastic to high pressure container - Google Patents

Description

  The present invention relates to a method of stably supplying waste plastics into a slurry by mixing waste plastics in a solvent, and supplying the obtained waste plastics slurry to a hydrogenation reaction vessel for waste plastics that is subjected to hydrogenation treatment under high temperature and high pressure.

  A large amount of various plastics used for OA equipment, car shredders, home appliances, beverage containers, food packaging containers, and the like are discarded as industrial waste and general waste. This waste plastic was disposed of in a predetermined landfill or incinerated in a garbage incinerator.

  In the former landfill disposal, various wastes including waste plastics are landfilled in a mixed state, causing environmental problems such as soil contamination and groundwater contamination. In the latter incineration disposal, waste plastics are high in calories. As a result, there is a problem in that high temperature combustion occurs, thereby damaging the combustion furnace and shortening the life.

  In addition, from the viewpoint of the recent rise in crude oil and the protection of the global environment, material recycling in which plastic products are crushed into pellets and reused as raw materials has become common. However, various plastics are used for discarded plastic products depending on the intended use. Therefore, if plastic waste is not collected manually by plastic type after it is collected, excellent material recycling is achieved. Since it cannot be used as a raw material, and the separation work is necessary, there is an essential problem that the recovery cost is inevitably increased.

  For this reason, material recycling is suitable when waste plastics with similar shapes and sizes and similar materials are used, such as PET bottles. However, even in this case, the use of recycled molded products is limited to simple molded products such as textile products, flower pots, piles, U-shaped grooves, etc., and they still have great expectations. Absent.

  For the above reasons, a method of thermally decomposing waste plastics under a nitrogen atmosphere, or hydrogenating under high temperature and high pressure to hydrocrack and return to chemical raw materials such as light oil, and manufacturing plastics from these chemical raw materials Chemical recycling has been proposed (see, for example, Patent Documents 1 and 2).

  In addition, it has been proposed to pulverize waste plastic at a preparation stage for chemical recycling (see, for example, Patent Document 3).

JP 05-186632 A JP 2003-321682 A JP 2004-346107 A

  The chemical recycling described in Patent Document 1 is to produce light oil by hydrocracking and liquefying waste plastic using a catalyst in a hydrogen atmosphere under high temperature and high pressure.

  In the chemical recycling described in Patent Document 2, waste plastic is heated and liquefied in coal tar, etc., hydrogen gas is added to this and subjected to hydrocracking reaction under high temperature and high pressure, and then the reaction product is circulated. The reaction is carried out in the presence of an oxidization catalyst to produce benzene, toluene, xylene (BTX) and the like.

  All of these methods are technologies that supply waste plastic to a high-temperature and high-pressure hydrogenation reactor and perform a hydrogenation reaction to convert it to light oil. Supply is an important point of technology.

(Problems of waste plastic slurry)
As a pre-treatment method (slurry method) of waste plastic when performing chemical recycling, for example, a method is proposed in which waste plastic is pulverized (for example, 200 μm or less) and mixed with oil such as heavy oil to form a slurry. (See Patent Document 3).

  The waste plastic used as the raw material for slurrying described in Patent Document 3 is pulverized into a fine powder of 200 μm. For this pulverization, a special pulverization method such as freeze pulverization is employed because of the heat generation. Therefore, there is a problem that the grinding cost becomes very expensive.

  Since this finely pulverized waste plastic is lightweight and has a low density, it tends to float when it is mixed with heavy oil, making it difficult to mix. In particular, when this fine powder is mixed with a solvent to form a slurry and the concentration thereof is further increased, the waste plastic slurry loses its fluidity and is difficult to transport with a pump or the like.

  Therefore, the concentration of the waste plastic contained in the slurry that can be transported by a pump is about 20 wt% at the maximum, and those having a concentration higher than this can not be pumped.

  In order to stably supply waste plastic slurry into a high-temperature and high-pressure hydrogenation reactor (tank) and perform hydrocracking, it is necessary that the waste plastic slurry be sufficiently fluid. is there.

  The waste plastic slurry supplied to the hydrogenation reactor, which constitutes the waste plastic processing equipment, contains a catalyst such as an iron-based catalyst (fine powder solids), so it is fully dispersed It is necessary to make a waste plastic slurry. Furthermore, if there is a part where the flow is stagnant during the transfer, solids such as catalyst and undissolved waste plastic particles in the waste plastic slurry are separated and deposited on the inner surface of the pipe, and solidified and blocked at that part. This problem must be taken into account.

  Slurry supply in general high-temperature and high-pressure waste plastic hydrogenation process is a slurry preparation tank that mixes waste plastic pulverized to a certain particle size and solvent (heavy oil) to prepare slurry, and waste plastic prepared therewith The slurry is transferred intermittently, and the waste plastic slurry is stirred and dispersed in the tank, and a part of the slurry is stably supplied to the supply port of the high-pressure plunger pump, and the slurry is supplied from the slurry supply tank. Use of a reciprocating pump such as a high-pressure plunger pump that can generate high pressure to supply waste plastic slurry to a high-temperature and high-pressure hydrogenation reactor (operating conditions: 5 to 15 Mpa, 350 to 480 ° C.) is required.

  As described above, when waste plastic slurry is supplied to the reactor by a high-pressure plunger pump, the slurry stays in the pump supply pipe of the high-pressure plunger, the pump supply port, or the valve seat portion of the pump. There is a problem that it is easily clogged.

  That is, since the supply amount to the reactor is continuously supplied in a constant amount according to the hydrocracking reaction, the amount per unit time is relatively small. In addition, the pressure of the pulsation of the piston is transmitted to the pump supply port and valve seat, and in addition to the low flow rate of the waste plastic slurry in this part, the catalyst in the slurry, undissolved waste plastic particles, etc. Separation of “solids” is facilitated.

  The solid content thus separated accumulates on the inner wall surface of the supply pipe and the supply port of the pump, the pump valve seat, and the like, and when this accumulation state proceeds, it becomes a great resistance to the supply of the waste plastic slurry as the raw material. Eventually, the supply port, the supply pipe, the valve seat of the pump, and the like are closed, making it difficult to stably supply the slurry.

(Object of the present invention)
The present invention is a slurry in which waste plastic pulverized to a fixed particle size and oil as a solvent are mixed and slurried in a temperature range where most of the waste plastic is dissolved in the solvent and the waste plastic or solvent is not gasified. After the waste plastic slurry obtained in the preparation tank is intermittently transferred to the slurry supply tank, the waste plastic slurry is stirred and dispersed in the same temperature range as the slurry preparation tank in the slurry supply tank, and a part of it is pressurized. When supplying to the hydrogenation reactor that performs high-temperature and high-pressure hydrocracking reaction with stable supply to the supply port of the plunger pump, the supply port of the high-pressure plunger pump that generates high pressure, the valve seat of the pump, or this supply Solids such as catalyst and undissolved waste plastic particles contained in the slurry are separated on the inner wall surface of the supply pipe (short pipe) connected to the mouth. But it is to be prevented from being deposited and closed the first object.

  A second object of the present invention is to stably supply a predetermined amount of high-pressure waste plastic slurry discharged by the high-pressure plunger pump.

  Furthermore, it is a third object to provide a method for efficiently converting waste plastic to light oil by hydrocracking.

  The present invention is configured as follows.

1. According to the first aspect of the present invention, in the slurry preparation tank, the solvent, the pulverized waste plastic, and the solid content not melted by the solvent are stirred and mixed in a temperature range where the waste plastic and the solvent do not gasify, and the waste plastic is obtained. Manufacturing a waste plastic slurry in which most of the melted, intermittently transferred the waste plastic slurry to a slurry supply tank, while stirring and dispersing in the temperature range where the waste plastic slurry is not solidified in the slurry supply tank, A method in which a constant amount is continuously supplied to a high-temperature and high-pressure hydrogenation reactor through a supply pipe connected to a lower portion of the slurry supply tank and a high-pressure slurry pump, and a hydrocracking reaction is performed to convert waste plastic into light oil. In
The waste plastic slurry is extracted from the lower part of the slurry supply tank, and a flow rate adjusting valve is provided between the discharge part of the slurry circulation pump installed in the slurry circulation line for supplying to the upper part of the tank and the discharge part of the upper part of the tank, A pressure adjustment pipe is formed between the discharge part of the slurry circulation pump and the flow rate adjustment valve, and the pressure adjustment pipe is connected to the supply pipe of the high pressure slurry pump so as to supply the waste plastic slurry to the high pressure slurry pump. When the solid content in the slurry separates and accumulates on the supply pipe part or the valve seat part of the high-pressure slurry pump, the flow control valve is connected to the pressure in the pressure control pipe. And the operation is performed so as to increase the pushing pressure (back pressure) into the high-pressure slurry pump.

  2. The invention of claim 2 is characterized in that the opening / closing operation of the flow regulating valve is performed by a signal of a sensor provided at the bottom of the slurry supply tank for measuring the weight of the slurry in the tank.

  3. The invention of claim 3 is characterized in that the supply pipe of the high-pressure slurry pump is connected to the upper part from the bent part of the pressure adjusting pipe.

  4). The invention according to claim 4 is characterized in that the flow rate adjusting valve is intermittently opened and closed to pulsate the slurry flowing in the circulation pipeline.

5. The invention of claim 5 is characterized in that a high-pressure plunger pump is used as the high-pressure slurry pump .

6). The invention of claim 6 is characterized in that the sensor for measuring the weight of the slurry in the slurry supply tank uses a load cell.

  The present invention has the characteristics described in the above items 1 to 6. In particular, as described in item 1, the waste plastic slurry e extracted from the bottom of the slurry supply tank 3 is supplied to the circulation pipeline 36. The slurry is supplied to the upper portion of the slurry supply tank 3 to efficiently agitate and disperse the slurry, and a flow rate adjusting valve is provided in the middle of the circulation pipeline 36, and the discharge portion of the slurry circulation pump, A “pressure adjusting pipe” is formed between the adjusting valve and the adjusting valve.

  And, by increasing the pressure of the slurry in the pressure adjustment pipe by operating the flow rate adjustment valve, the back pressure of the slurry in the pressure adjustment pipe to the high-pressure slurry pump is increased, and solid matter accumulation is prevented. Can do.

  That is, a strong pushing pressure (back pressure) can be applied to the slurry flowing in the supply pipe connected to the pressure adjusting pipe or the valve seat portion of the high pressure slurry pump. As a result, the high-pressure slurry pump slows down or stops, and the slurry stagnates in the supply pipe. During that time, “solids” such as catalyst and undissolved waste plastic particles separated from the slurry accumulate on the inner wall of the pipe. Or even when it is accumulating, it is possible to prevent and cancel the accumulation of this solid content, and to smoothly supply the waste plastic slurry to the high-temperature and high-pressure reactor, and to perform a highly efficient hydrocracking reaction. .

(Outline of waste plastic slurry feeder)
Embodiments according to the present invention will be described below with reference to the drawings.

  As shown in FIG. 1, the basic configuration of the waste plastic slurry supply apparatus 1 includes a slurry preparation tank 2 and a slurry supply tank 3 positioned on the downstream side thereof. The slurry preparation tank 2 includes a stirring device 4 for stirring the supplied solvent a, a waste plastic tank 5 for supplying waste plastic b pulverized to a constant particle size in the slurry preparation tank 2, and a slurry preparation tank 2 A temperature sensor 6 for measuring the temperature of the solvent a and an electric heater 7 for heating the mixing tank 2 are provided.

  As the solvent a, heavy oil such as coal tar oil or hydrogenated solvent is preferably used. In addition, a certain amount of a catalyst for iron-based hydrocracking reaction such as iron oxide, iron sulfide, iron chloride, blast furnace slag, etc., is mixed in the solvent in advance, as described later. Immediately before being supplied to the hydrocracking reactor, if a staying state occurs, it has the property of being easily separated from the waste plastic slurry.

  The waste plastic tank 5 is provided with a valve 9 in the waste plastic b supply pipe 8 connected to the tank 5 and the slurry preparation tank 2, and the control device 10 that operates based on an input signal from the temperature sensor 6 controls the valve 9. It is designed to control opening and closing.

  The control device 10 is controlled by the electric heater 7 so that the temperature of the solvent a in the slurry preparation tank 2 is not gasified (for example, 150 to 240 ° C., preferably 170 to 220 ° C.). .

  Further, the temperature sensor 6 has a liquid level of the solvent a in order to make it easy to measure the temperature drop of the liquid level of the solvent a, which changes in relation to the filling amount of the waste plastic b put into the slurry preparation tank 2. It is necessary to install between just below and the center of the tank.

  The waste plastic b may be any plastic that can generate low molecular weight hydrocarbons by hydrocracking reaction, and almost all types of plastics and mixtures thereof are targeted. This is not limited to thermoplastic resins, but also thermosetting resins.

  Resins suitable for treatment according to this invention include polyolefin resins, for example, thermoplastic resins such as polyethylene, polypropylene, polystyrene resins and mixtures thereof, but chlorine containing resins such as polyvinyl chloride and polyvinylidene chloride. It may be mixed.

  In the present invention, these chlorine-containing resins show a catalytic action in hydrocracking, and a liquefied product with a higher light oil content is obtained. Meaning of improving the efficiency of slurrying and hydrocracking reaction by applying waste plastic pulverized to a certain range of particle size (for example, 0.5-5mm) obtained by pulverizing waste plastic in municipal waste Suitable for.

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

  The stirring device 4 is formed by a rotating shaft 16 that passes through the lid portion 15 of the tank main body 11 and reaches the outlet 13 of the tank throttle portion 12, and a stirring blade group 17 fixed to the rotating shaft 16 in multiple stages. The angle of elevation in the rotation direction is such that the solution a is agitated and flows down along the rotation axis 16 at the same time. On the other hand, the lowermost stirring blade has an elevation angle opposite to the elevation angle, and simultaneously agitates the solution a and pushes it downward along the wall surface of the mixing tank 2. It is designed to prevent clogging due to accumulation near the outlet.

  A solvent injection nozzle 20 is provided in the lid portion 15 of the slurry preparation tank 2, and the solvent a extracted from the solvent extraction pipe 21 provided in the tank throttle portion 12 is sprayed from the solvent injection nozzle 20 onto the upper surface of the waste plastic b. It has become. The solvent spray nozzle 20 is provided with a stirring blade 18 so that the solvent a sprayed from the solvent spray nozzle 20 is sprayed on the upper surface of the waste plastic b floating in the form of fine powder dropped from the waste plastic supply pipe 8. Is disposed on the downstream side of the waste plastic charging pipe 8 in the direction of the rotation.

  Further, a light fraction collection device 22 is provided in the upper part of the slurry preparation tank 2 so that components evaporated in the waste plastic solution are recondensed and returned to the slurry preparation tank 2. This light fraction recovery device 22 is a kind of condenser, and recovers by supplying cooling water c to the jacket portion of the light fraction recovery device 22 in the middle of the exhaust pipe 23 provided in the upper part of the slurry preparation tank 2. The inside of the apparatus 22 is rapidly cooled. Further, the slurry preparation tank 2 is provided with a solvent supply pipe 26 having a valve 25 disposed on the upper side surface thereof.

  A slurry pipe 30 provided with a slurry transfer pump 38 comprising a slurry centrifugal pump is connected to the top plate of the slurry supply tank 3 disposed adjacent to the outlet valve 14 provided at the discharge port of the slurry preparation tank 2. The waste plastic slurry d is supplied to the upper part of the slurry supply tank 3 which is the next step.

  This slurry supply tank 3 is a high-pressure slurry pump that supplies a constant amount of stable slurry so that the slurry can be uniformly stirred and mixed to efficiently promote the reaction in the high-temperature and high-pressure reactor in the hydrocracking reaction step. Is provided with an agitator 33 driven by an electric motor 32, and an electric heater 34 is provided on a side surface thereof.

  Furthermore, a “circulation pipeline 36” is provided to communicate the discharge port 35 at the bottom of the slurry supply tank 3 with the top plate 31 of the tank 3, and the waste plastic slurry e in the tank 3 is supplied to the slurry supply tank 3; The slurry is circulated at a predetermined circulation speed while being pressurized by a slurry circulation pump 39 between the circulation pipeline 36 provided outside the tank 3.

  Further, the waste plastic slurry e in the slurry supply tank 3 is fed into the high-temperature and high-pressure hydrogenation reactor 50 (pressure 5.0 to 1.5 MPa) by the supply pipe 37 connected above the bent portion X of the circulation pipeline 36. , Temperature 350 to 480 ° C.).

  Here, as the concentration (component) of the waste plastic slurry, the conditions of waste plastic 10 to 40 wt%, Fe-based catalyst 0.1 to 10 wt%, solvent (coal tar oil) 50 to 90 wt% were adopted as representative examples.

  A slurry transfer pump (centrifugal pump) 38 is disposed in the first pipe 30 connected to the slurry preparation tank 2, and a slurry circulation pump is connected to the circulation pipe 36 connecting the upper and lower sides of the slurry supply tank 3. 39 (centrifugal pump) is arranged.

  A supply pipe 37 connected in a branched manner to the upper part of the throttle portion of the circulation pipe 36 has a capability of transferring the high-pressure slurry e by a high-pressure slurry pump 40 (reciprocating pump such as a plunger pump). .) Is arranged.

(Operation method of waste plastic processing equipment)
Next, the operation method of the waste plastic processing apparatus 1 will be described. A predetermined amount of solvent (in this example, containing Fe (0.001 mm to 0.01 mm)) from the solvent supply pipe 26 to the slurry preparation tank 2 (in this example) When the coal tar oil (a) is supplied, the electric heater 7 is energized and heated by the control signal of the control device 10, and 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, and a small amount (for example, the final value) that has passed through the valve 9 during that time. A certain amount of the waste plastic b 1 to 1/10 of the amount charged is charged into the slurry preparation tank 2 and mixed with the solvent to be dissolved.

  The fine powdery waste plastic b introduced into the waste plastic preparation tank 2 is wetted by the solvent a sprayed from the solvent spray nozzle 20, so that it becomes easy to become familiar with the solvent a in the adjustment tank 2 and has a weight. It increases and becomes easy to settle in the preparation tank 2. Moreover, it becomes easy to melt | dissolve in the solvent a in the preparation tank 2 with the drawing-in force of the uppermost stirring blade.

  When the waste plastic b is supplied from the waste plastic tank 5 into the preparation tank 2 and partially dissolved, the liquid surface temperature of the solvent a in the preparation tank 2 is slightly lowered. When the solvent temperature reaches a second set temperature (for example, 160 ° C.), the control device 10 opens and closes the valve 9 of the supply pipe 8 for a certain period of time, and during that time a small amount (for example, 1 of the total amount of final charge) has passed through the valve 9. A certain amount of waste plastic b is charged into the slurry preparation tank 2.

  When such a waste plastic b charging operation is repeated and the entire amount of the preset waste plastic b is charged, the temperature of the solvent a in the preparation tank 2 is set to a set value (for example, 150 to 240 ° C., preferably 170 to While maintaining the temperature at 220 ° C., the inside of the preparation tank 2 is stirred for a certain time by the stirring device 4 to dissolve most of the waste plastic b in the solvent a.

  After the melting operation of the waste plastic b in the slurry preparation tank 2 is completed, the outlet valve 14 of the preparation tank 2 is opened, and the slurry transfer pump 38 is driven so that the waste plastic slurry d in the slurry preparation tank 2 is transferred to the slurry supply tank 3. Transfer the entire amount.

  After a predetermined amount of waste plastic and oil waste plastic slurry d are transferred, the outlet valve 14 of the slurry preparation tank 2 is closed, and the slurry transfer pump 38 is stopped. Thereafter, the above-described melting operation of the waste plastic b is similarly restarted in the slurry preparation tank 2.

  On the other hand, in the slurry supply tank 3, the waste plastic slurry d (indicated as slurry e in the slurry supply tank) is maintained at a set temperature that is the same as or close to that in the slurry preparation tank 2 by the heater 34. In operation, the waste plastic slurry e is further stirred and dispersed, and a constant amount of a stable slurry is continuously supplied via a high-pressure slurry pump 46.

  Then, the waste plastic slurry e in the slurry supply tank 3 is circulated by the slurry circulation pump 39 between the slurry supply tank 3 and the circulation pipeline 36 piped outside the slurry supply tank 3, In addition to preventing the generation of gum in the waste plastic slurry e and applying a pressure (back pressure) of the slurry to the high-pressure slurry pump 40, the slurry e can be stably supplied to the high-temperature high-pressure hydrogenation reactor 50. be able to.

  In this way, the waste plastic slurry e in the slurry supply tank 3 passes through the high-pressure slurry pump 40 and the pipe 41 to the high-temperature high-pressure hydrogenation reactor 50 (pressure 5.0 to 1.5 MPa, temperature 350 to 480 ° C.). To be supplied. In the reactor 50, the hydrocracking reaction is performed at a reaction temperature of 350 to 480 ° C. and a reaction pressure of 5 to 15 MPa.

  The reaction time in the reactor 50 is 30 to 120 minutes, and the waste plastic is hydrogenated by the hydrocracking reaction, and mainly light oil or the like is produced.

(Reexamination of problems in supplying slurry e to hydrogenation reactor 50)
FIG. 2 shows a portion of the piping indicated by the arrow X in FIG. 1, and T between the circulation pipeline 36 and the supply pipe 37 between the high-pressure slurry pump 40 (plunger pump) for transferring the high-pressure slurry. The part connected to the mold is shown.

  The portion where the circulation pipeline 36 and the supply pipe 37 are connected in a T shape has a length (m) (the length of the pump supply pipe 37) for convenience of piping to the high-pressure slurry pump 40. Yes. This length (m) is the portion where the waste plastic slurry e stagnates when the plunger pump 40 is stopped, so that the catalyst or unseparated from the slurry e during this stagnation is not present. The dissolved plastic and the solid content k contained in the dissolved waste plastic are separated and settled in the supply pipe 37. Similar settling and adhesion of solid content is likely to occur at the valve seat in the high-pressure slurry pump 40.

  In the present invention, in consideration of the separation of the solid content k and the problems of sedimentation and clogging of the solid content k in the valve seat portion of the supply pipe 37 and the high-pressure slurry pump 40 that occur along with this separation, the circulation is performed. The configuration is such that the pressure (back pressure) of the slurry e flowing through the pipeline 36 into the high-pressure slurry pump 40 can be adjusted, and a supply pipe 37 is connected to the circulation pipeline 36.

  The bent portion Y of the circulation pipeline 36 and the connection portion of the supply pipe 37 are connected to a position slightly displaced upward from the horizontal pipe 36b connected to the circulation pump 39, so that the solid content k It is possible to prevent the supply pipe 37 from depositing or sticking to the inner wall surface due to the accumulation of the.

  A load cell 60 is provided below the slurry supply tank 3, and a signal S is output when the load cell 60 changes the weight of the waste plastic slurry in the slurry supply tank 3, and the supply amount of the slurry e to the reactor 50 is constantly set. It comes to detect.

  The signal S is also configured to control the flow rate of the flow rate control valve 62 by the control device 61, to control the pressure in the pressure adjusting pipe, and to control the pushing pressure (back pressure) to the high pressure slurry pump 40. Has been.

  Since the slurry circulation pump 39 is always driven, the waste plastic slurry e extracted from the bottom of the slurry supply tank 3 is supplied to the circulation pipeline 36 and the flow rate is controlled by the flow rate control valve 62 while the slurry supply tank 3 is restricted. It is comprised so that it may reflux from the upper part of.

  Accordingly, the waste plastic slurry e is operated so as not to stagnate inside the circulation pipeline 36, and the supply pipe 37 connected to the circulation pipeline 36 is always supplied with fresh plastic slurry. e should be supplied.

  Further, the supply pipe 37 to the high-pressure slurry pump 40 is connected in a T shape slightly above the bent portion Y of the circulation pipeline 36 to prevent selective inflow of the solid content k to the supply pipe 37. It is possible to prevent clogging such as accumulation and adhesion of the solid content k on the supply pipe 37.

  However, when the waste plastic slurry e is not supplied to the reactor 50 or when the supply amount is reduced, a catalyst or the like is provided inside the supply pipe 37 or the valve seat portion of the high-pressure slurry pump as shown in FIG. The solid content k is separated and deposited on and adhered to the tube wall. Finally, the tube is closed and the waste plastic slurry e cannot be supplied to the reactor 50.

  Therefore, by controlling the flow rate control valve 62 by the signal of the load cell 60 and restricting the flow rate control valve 62, the inside of the “pressure-produced pipe 36A” between the slurry circulation pump 39 and the flow rate control valve 62 is controlled. The pressure is increased.

  The pressure increase generated by the operation of the flow control valve 62 increases the pressure (back pressure) for pushing the waste plastic slurry e flowing through the pressure adjusting pipe 36A into the supply pipe of the high-pressure slurry pump 40.

  Due to the change in the pushing pressure of the waste plastic slurry e, the pressure inside the supply pipe 37 shown in FIG. 2 is increased, and at the same time, the flow rate of the “bent portion Y” of the circulation pipeline 36 is changed. The internal pressure fluctuates and an “extrusion phenomenon, a suction phenomenon, or a disturbance phenomenon” occurs.

  Due to the extrusion phenomenon, the suction phenomenon, or the disturbance phenomenon, the slurry accumulated in the supply pipe 37 is shaken, and the solid content k such as the catalyst accumulated on the inner wall of the pipe or the pump valve seat is peeled off. The solid content k thus passed through the high-pressure slurry pump 40 together with the waste plastic slurry e is transferred to the high-temperature high-pressure hydrogenation reactor 50 or mixed in the circulating dispersion slurry e.

  Therefore, due to the pressure fluctuation in the pressure adjusting pipe 36A, the slurry inside the supply pipe 37 and the slurry pump 40 is affected, and the accumulated solid content k is peeled off and removed.

  As described above, the “pressure adjusting pipe 36A” constituting the starting end portion of the circulation pipeline 36 is forced to give a pressure fluctuation, thereby generating an “extrusion phenomenon and a suction phenomenon” generated in the pressure adjusting pipe 36A. , Or a disturbance phenomenon, due to the influence of pressure fluctuations in the supply pipe 37 (and the suction port 40a of the high-pressure slurry pump 40) connected to the pressure adjustment pipe 36A, and the pressure change of the pressure adjustment pipe 36A. The solid content k deposited on the inner wall surfaces of the supply pipe 37 and the valve seat of the slurry pump 40 is separated and separated.

  By always circulating the waste plastic slurry e through the circulation pipeline 36 (including the pressure adjusting pipe 36A) and causing the supply pipe 37 to exhibit a kind of “extrusion phenomenon, suction phenomenon”, this supply is achieved. If the waste plastic slurry e inside the pipe 37 is given a vibration effect and the length (m) of the supply pipe 37 is formed within the range of the “extrusion phenomenon, suction phenomenon”, this supply pipe It is possible to prevent a phenomenon in which the solid content f in the slurry inside 37 separates and deposits on and adheres to the tube wall and sometimes clogs.

  The length (m) of the supply pipe 37 is determined by various factors such as the nature of the dispersion slurry e, the speed of the slurry e flowing through the circulation pipeline 36, the viscosity of the slurry, and the temperature of the slurry. It is desirable to make it as short as possible.

(Other connection structure of the supply pipe 37)
3 shows an embodiment in which the supply pipe 37 is linearly connected to the bent portion Y of the circulation pipeline 36 (36A). FIG. 4 shows the supply pipe 37 with respect to the center g of the circulation pipeline 36. In the embodiment, the center is shifted and fixed upward by a distance (n).

  The second embodiment shown in FIG. 3 is not desirable because there is a selective mixing of the solid content k into the supply pipe 37 of the waste plastic slurry e.

  Example 3 shown in FIG. 4 shows a configuration that exerts the effect of extruding and sucking the dispersion slurry e generated in the bent portion Y, but it is desirable that the distance (n) be equal to or longer than a certain length.

  The fourth embodiment shown in FIG. 5 is a modification of the embodiment shown in FIG. 4, and an upward face portion 37 a is provided on the upper portion of the supply pipe 37 to further exert an extrusion effect and a suction effect.

  As described above, in the present invention, in order to prevent the solid content k such as the catalyst from being accumulated in the supply pipe portion and the valve seat portion of the plunger pump which is the high-pressure slurry pump 40, A circulation pipeline 36 connecting the upper and lower sides is provided, and a pressure adjustment pipe 36A is formed on a part (starting end side) of the circulation pipeline 36, and the flow rate adjustment valve 62 provided in the middle of the circulation pipeline 36 is used to A pressure fluctuation is given in the pressure adjusting pipe 36A, whereby solid content k accumulates in the supply pipe 37 of the high pressure slurry pump 40 connected to the pressure adjusting pipe 36A and in the valve seat portion of the slurry pump 40, Eventually, it will prevent troubles that block.

It is a figure which shows the whole structure of a waste plastic slurry supply apparatus. It is a figure which shows the connection part of a high pressure slurry pump and a pressure adjustment pipe. It is a figure which shows the connection part of a high pressure slurry pump and a pressure adjustment pipe. It is a figure which shows the connection part of a high pressure slurry pump and a pressure adjustment pipe. It is a figure which shows the connection part of a high pressure slurry pump and a pressure adjustment pipe.

DESCRIPTION OF SYMBOLS 1 Waste plastic slurry supply apparatus 2 Waste plastic slurry preparation tank 3 Waste plastic slurry supply tank 36 Circulation pipeline 36A Pressure adjustment pipe 37 Supply pipe 38 Waste plastic slurry transfer pump 39 Waste plastic slurry circulation pump 40 High pressure slurry pump (high pressure plunger pump )
a Solvent (heavy oil)
b Waste plastic pulverized to a fixed particle size d, e Waste plastic slurry k Solid content Y Curved part

Claims (6)

In the slurry preparation tank, most of the waste plastic was melted by stirring and mixing the solvent, the pulverized waste plastic, and the solid content not melted in the solvent in a temperature range where the waste plastic and the solvent are not gasified. A waste plastic slurry is manufactured, the waste plastic slurry is intermittently transferred to a slurry supply tank, and the waste plastic slurry is stirred and dispersed in a temperature range where the waste plastic slurry is not solidified in the slurry supply tank. In a method of continuously supplying a constant amount to a high-temperature and high-pressure hydrogenation reactor through a supply pipe connected to a high-pressure slurry pump and converting the waste plastic to light oil by hydrocracking reaction,
The waste plastic slurry is extracted from the lower part of the slurry supply tank, and a flow rate adjusting valve is provided between the discharge part of the slurry circulation pump installed in the slurry circulation line for supplying to the upper part of the tank and the discharge part of the upper part of the tank, A pressure adjustment pipe is formed between the discharge part of the slurry circulation pump and the flow rate adjustment valve, and the pressure adjustment pipe is connected to the supply pipe of the high pressure slurry pump so as to supply the waste plastic slurry to the high pressure slurry pump. To configure
When the situation becomes such that the solid content in the slurry separates and accumulates on the supply pipe part or the valve seat part of the high-pressure slurry pump, the pressure in the pressure adjustment pipe is increased, A method for supplying a slurry containing waste plastic to a high-pressure vessel, wherein the operation is performed so as to increase a pressure applied to the high-pressure slurry pump.   2. The waste plastic slurry according to claim 1, wherein the opening / closing operation of the flow rate adjusting valve is performed by a signal of a sensor provided at the bottom of the slurry supply tank for measuring the weight of the slurry in the tank. How to supply to.   2. The method of supplying waste plastic slurry to a high pressure vessel according to claim 1, wherein a bent portion is formed in the pressure adjusting pipe, and a supply pipe of a high pressure slurry pump is connected above the bent portion.   2. A method for supplying waste plastic slurry to a high-pressure vessel according to claim 1, wherein the flow control valve is intermittently opened and closed to pulsate the waste plastic slurry flowing in the circulation pipeline. High-pressure slurry pump is characterized the plunger pump der Turkey, a method of supplying waste plastics slurry of claim 1 wherein the high pressure vessel. The method for supplying waste plastic slurry to a high-pressure vessel according to claim 2, wherein the sensor for measuring the weight of the slurry in the slurry supply tank is a load cell.

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