JP6631795B2 - Waste plastic oiling system - Google Patents

Description

  The present invention relates to a waste plastic decomposer for thermally decomposing and gasifying waste plastic while reacting it with a catalyst, and a waste plastic regenerated as a petroleum product by further distilling cracked oil produced by cooling after gasification. It relates to an oiling system.

The present inventor has provided a waste plastic oiling device having a structure described in Patent Document 1 for the purpose of continuous oiling operation of pulverized waste plastics and efficient discharge of residues.
In this waste plastic oiling device, a heating medium is sealed between a dissolving and evaporating tank having a funnel-shaped bottom and a heating medium tank containing the melting and evaporating tank. It is placed in a heating furnace, and the inside of the melting and evaporating tank is heated through a heat medium by a burner installed in the heating furnace. In the dissolving and evaporating tank, the waste plastic collected at the bottom of the funnel is stirred together with the catalyst so as to be spirally wound with a stirring screw, and this is repeated and dissolved. The evaporated gas is discharged from the upper part of the dissolution and evaporation tank, cooled by an external cooling device and liquefied.When the residue is accumulated in the dissolution and evaporation tank, the screw screw conveyor, which is coaxial with the stirring screw, is reversed to dissolve. The residue in the evaporation tank is discharged from a funnel-shaped bottom end.
The oiling device described in Patent Document 2 is basically the same as that described in Patent Document 1, although it does not use a heat medium and differs in the structure of the stirrer.

On the other hand, the waste plastic oiling system described in Patent Document 3 has the following configuration.
(1) Waste plastic is first melted in a melting tank, separated into a liquid phase and a gas phase, and separated into a liquid phase line and a gas phase line for treatment. The melting tank is heated indirectly with a heating medium.
(2) In the liquid phase line, the separated liquid phase is thermally decomposed in a pyrolysis tank at the latter stage of the melting tank, and then contacted with a catalyst in a reaction tank to reform into a light gas, which is cooled in a separation tank. Separates into gas and product oil.
(3) In the gas phase line, the oil produced in the liquid phase line is supplied to the spray tower, stirred and cooled while passing through an external oil cooling system, and then circulated. By spraying from a spray, the gas flowing into the spray tower is quenched with spray oil, sublimates contained in the gas are precipitated in the oil, and high-boiling fractions are condensed and collected as oil in the tank. I do.
(4) The gas that has passed through the gas-line spray tower is cooled to room temperature by a condenser, and a low-boiling fraction is condensed by a condenser. The condensed low-boiling fraction is used as a liquid fuel in an incinerator, a heating medium heating furnace for a melting tank, and the like. Hydrogen chloride-rich gas that does not condense even when cooled to room temperature is led to an incinerator for incineration.
(5) The gas separated in the liquid phase line is also used as fuel for the heating medium heating furnace.

JP 2013-234216 A JP-A-8-311459 JP 2002-80861 A

The prior arts of Patent Document 1 and Patent Document 2 described above have the following problems.
(1) In the dissolution evaporating tank, the unmelted waste plastic and the catalyst are agitated so as to converge at the center of the bottom of the funnel and spirally roll up, and the cracked oil produced by melting is also funnel-shaped. These solids and liquids are not separated because they converge at the center of the bottom and are stirred together, and the unmelted waste plastic and cracked oil before evaporation are constantly stirred in a solid-liquid mixed state, resulting in gasification. Performance is reduced.
(2) Because of such agitation, the residue after the thermal decomposition necessarily gathers at the center of the bottom and is stirred together, so that the thermal efficiency of waste plastic that has not been thermally decomposed is poor, and the decomposition is also performed. It is practically impossible to discharge only the residue inside, and after the entire thermal decomposition is completed, a batch-type process of discharging the residue by rotating the discharge screw conveyer in reverse with the stirring screw must be adopted. Absent. The discharge is carried out after the temperature of the dissolved evaporating tank is lowered, and the temperature of the dissolved evaporating tank must be raised to a high temperature in order to restart the operation. Therefore, the processing capacity per unit operating day is low, and the fuel efficiency is low.
(3) Since the bottom of the dissolution / evaporation tank is formed into a funnel shape to stir repeatedly with convergence and spiral winding, it is difficult to increase the size of the dissolution / evaporation tank due to the limitation of the stirring range. Processing cannot be performed.
(4) A heat medium is sealed between the dissolution / evaporation tank and the heat medium tank, and these double tanks are arranged in a heating furnace, and a burner is installed in the heating furnace to form a double tank. The space between the furnace and the heating furnace is a flue, and the melting and evaporating tank is heated through the flue and the heat medium, so that the temperature irregularity easily occurs in the flue and the heat medium is sealed. Therefore, its thermal conductivity is poor, and heating temperature unevenness and heat loss are large. Further, it is difficult to control the temperature for heating.

  On the other hand, according to the conventional technique of Patent Document 3, only two types of oil components, a high-boiling fraction and a low-boiling fraction, can be extracted. Looking at the process, waste plastic is melted in a melting tank without a catalyst and separated into a liquid phase and a gaseous phase. The step of reacting with the catalyst and the step of separating the generated oil and gas by the separation tank are sequentially performed. Also, in the gas phase line, a cooling step of cooling while circulating the oil, the cooling oil is sprayed from a spray in a spray tower to rapidly cool the gas, to precipitate a sublimate in the oil, and a high boiling fraction. In addition to the precipitation-condensation step of condensing and recovering oil as oil, the gas that has passed through the spray tower is cooled to room temperature by a condenser and the low-boiling fraction is condensed by a condenser, requiring many steps as a whole. In addition, large-scale equipment is required.

The object of the present invention is
(1) Simultaneous input of waste plastics and catalyst and discharge of residue while enabling continuous operation every day, to improve throughput, operating rate and fuel efficiency per unit operating day;
(2) to improve the gasification efficiency by allowing the cracked oil generated by the thermal cracking to be automatically separated from the waste plastic not thermally cracked and the residue after the thermal cracking;
(3) Improving thermal efficiency for gasification by reducing heating temperature unevenness and heat loss;
(4) Even if the dissolution / evaporation tank is large, the above (1) to (3) can be performed, and large-scale continuous processing can be performed.
(5) To be able to economically and efficiently separate and regenerate highly marketable petroleum products such as gasoline, kerosene, light oil, etc., having different carbon numbers,
With the goal.

In order to achieve such an object, the waste plastic oiling system of the present invention includes a decomposition agitator rotated by an external motor in a heated drum-type decomposition and evaporation tank, A residue discharge screw that rotates simultaneously with a stirrer and discharges a residue through a discharge guide tube from the center of the bottom of the decomposition and evaporation tank, wherein the decomposition raw material and the catalyst charged into the decomposition and evaporation tank, A waste plastic decomposition apparatus provided with a number of stirring blades for converging to the center of the bottom while stirring on the bottom of the decomposition evaporation tank,
A primary cracked oil generating device that cools a gas component evaporated from the cracking and evaporation tank to generate a primary cracked oil,
A distillation stabilizing device that evaporates the primary cracked oil by heating it within a predetermined temperature range lower than the waste plastic cracking device in the distillation tank and returns residual oil to the cracking and evaporation tank,
A secondary cracked oil generating device that generates a secondary cracked oil having a carbon number of not more than a predetermined number by cooling a gas component evaporated from the distillation stabilizer,
A flash point adjusting device for heating the secondary cracked oil in a constant temperature heating tank while maintaining it at a substantially constant temperature lower than the heating temperature of the secondary cracked oil generating device, and performing evaporation at that temperature;
Is provided.
In the second aspect, the discharge guide pipe is further provided with an on-off valve that is opened by a residue pushing force by the discharge screw.

  According to the present invention, when the pulverized raw material obtained by pulverizing the waste plastic and the catalyst are put into a drum-shaped decomposition and evaporation tank, they are stirred on the bottom of the decomposition and evaporation tank by a number of stirring blades of a decomposition stirrer. It gradually converges to the center of the bottom while being performed. In the meantime, the pulverized raw material is thermally decomposed over a sufficient period of time, and the residue after pyrolysis is automatically discharged from the bottom center of the decomposition and evaporation tank through a discharge guide tube by a residue discharge screw that rotates simultaneously with the decomposition stirrer. Is discharged. Since the thermal decomposition operation and the residue discharging operation by the catalyst while following such a path are continuously performed for a sufficient time, the above-described objects (1) to (4) can be achieved, that is, the unit can be achieved. It is possible to improve the throughput per day, the operating rate and the fuel efficiency, the gasification efficiency, the heat efficiency for gasification, and a large amount of continuous processing.

Assuming that the process of pyrolysis and gasification by the waste plastic decomposer as described above is the first stage, the process of the second stage and the third stage is subsequently performed in order to make oil.
In other words, in the first stage treatment by the waste plastic decomposition apparatus, thermal decomposition is performed using a catalyst, so that thermal decomposition in which the number of carbon atoms is specified in a narrow range is avoided, and those having a large number of carbon atoms are included. Thermal decomposition. Incidentally, the cracked oil and cracked gas generated here have a wide carbon number range of about C1 to C40, and thus cannot be a petroleum product in which the carbon number is specified within a predetermined range.
Therefore, in the second stage, the gaseous matter evaporated from the cracking and evaporating tank is cooled to generate primary cracked oil, and then the primary cracked oil is heated by the distillation stabilizing device within a predetermined temperature range lower than that of the first stage. And distill. As a result, among those in the wide carbon number range in the first stage, those with a low carbon number evaporate and those with a high carbon number remain, so this residual oil is returned to the waste plastic cracking unit and pyrolyzed again. I do.
By setting the heating temperature in the second-stage distillation stabilizing device within a predetermined temperature range and controlling the temperature, the distillation is stably performed, and the first-stage thermal decomposition and the second-stage distillation are repeated. The number of carbon atoms can be narrowed down to a certain range, and a gaseous component evaporated with a carbon number lower than that is cooled to be a secondary cracked oil having a lower carbon number than a predetermined number.
In the next third stage, from the viewpoint of flash point adjustment intended to remove carbon components lower than this, the secondary cracked oil is further reduced in the constant-temperature heating tank to a temperature substantially lower than the heating temperature of the secondary cracked oil generator. Heat is maintained at a constant temperature, and evaporation is performed at that temperature.
By organically combining such different stepwise treatments, waste plastics containing a mixture of polypropylene (PP), polyethylene (PE), polystyrene (PS), etc. satisfy properties of petroleum standards such as JIS, that is, carbon Highly marketable petroleum products, such as gasoline, kerosene, and light oil, that meet the specifications for both properties of both the number and the flash point can be produced economically at a relatively low reaction temperature without the use of large-scale distillation equipment, and efficiently. It can be separated and reproduced separately.

  In the second aspect of the present invention, since the discharge guide pipe for discharging the residue is provided with the opening / closing valve that is opened by the residue pushing force by the discharge screw, the heat loss accompanying the discharge of the residue from the discharge guide pipe can be reduced.

It is a vertical sectional view of one example of a waste plastic decomposition device in the present invention. It is the side view which cut out one part. It is a top view. It is a top view of a stirrer for decomposition | disassembly. FIG. 5 is a partial plan view showing a change in a raw material transfer direction in a decomposition evaporation tank. It is a fragmentary vertical sectional view of a partial modification of a waste plastic decomposition device. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a layout diagram of an embodiment of a waste plastic oil conversion system of the present invention. This is the flow sheet.

  The present invention provides a waste plastic decomposer for thermally decomposing and gasifying waste plastic while reacting it with a catalyst, and a system including the same. The purpose of the present invention is to provide a waste plastic oil recycling system for recycling as a petroleum product having a low carbon number. This embodiment will be described as a second embodiment.

  1 to 5 show only an embodiment of the waste plastic decomposing apparatus 1 and do not show the processing at the preceding stage and the processing at the latter stage, but waste plastic mixed with PP, PE, PS, etc. After being subjected to pretreatment such as crushing, volume reduction, and cooling, the waste plastics are sent to the waste plastic decomposition apparatus 1. The crushed waste plastic sent in in this manner is hereinafter referred to as a “crushed raw material”.

  The waste plastic decomposition apparatus 1 has a drum-shaped decomposition evaporation tank 2 as a main body, and a circular ceiling wall 3, a circular bottom wall 4, and a cylindrical peripheral wall 5 of the decomposition evaporation tank 2 are all covered with a heat insulating material 6. Has become a heat insulating wall. The bottom wall 4 has a double wall structure in which a bottom cavity 7 is formed between a bottom inner plate 4a and a bottom outer plate 4b serving as bottom surfaces in the decomposition evaporation tank 2, and the peripheral wall 5 is also formed. The inner peripheral plate 5a and the outer peripheral plate 5b serving as inner peripheral surfaces in the decomposition evaporation tank 2 have a double wall structure in which a peripheral cavity 8 is formed therebetween. Between the bottom inner plate 4a and the bottom outer plate 4b and between the inner peripheral plate 5a and the outer peripheral plate 5b, the flow of the fluid heat medium flows from the central portion of the bottom cavity 7 to the peripheral portion, and further to the peripheral portion. A large number of ribs 9 made of a material having high thermal conductivity are provided to guide the cavity 8 from the lower part to the upper part and to improve the heat conduction to the bottom inner plate 4a and the inner peripheral plate 5a. It flows uniformly to every corner of 7.8, and uniformly heats the inside of the decomposition evaporation tank 2 with good thermal conductivity.

  In the center of the bottom wall 4, a residue discharge section 11 is formed by a discharge guide tube 10 that penetrates the inner and outer bottom inner plates 4 a and 4 b through the inside of this tube as a residue discharge path. A discharge screw 12 for discharging the residue from the decomposition / evaporation tank 2 is inserted into the discharge guide pipe 10, and a discharge pipe 12 is provided at an outer end (lower end) of the discharge guide pipe 10. Is provided with an on-off valve 14. The on-off valve 14 has a structure in which the outlet of the discharge guide tube 10, that is, the residue discharge port of the residue discharge unit 11 is normally closed from the outside (lower side) by a spring (not shown). The upper surface of the bottom inner plate 4a of the bottom wall 4 is an inclined surface that gradually rises from its peripheral edge toward the central residue discharge section 11. The inclination angle is preferably about 5 degrees with respect to the horizontal plane.

  Further, in order to introduce the heat medium from the center of the bottom cavity 7 and discharge and circulate the heat medium from the upper part of the peripheral cavity 8, a heat medium introduction pipe 15 is provided near the discharge guide pipe 10 on the bottom wall 4. A heat medium discharge pipe 16 is provided above the peripheral wall 5. The heat medium is heated by a heat medium heater (not shown in the first embodiment) outside the decomposition / evaporation tank 2, introduced into the bottom cavity 7 from the heat medium introduction pipe 15, and swirled therein to the periphery. The flow further rises while turning inside the peripheral cavity 8, and is discharged from the heat medium discharge pipe 16 and returned to the heat medium heater, thereby repeatedly circulating in the cavities 7.8. The inside of the decomposition evaporation tank 2 is indirectly heated by the circulation of the heat medium, and the heating temperature in the decomposition evaporation tank 2 is adjusted by controlling the flow rate while detecting the temperature before the introduction by a sensor.

On the other hand, on the ceiling wall 3, as shown in FIG. 3, a raw material charging section 17 is provided near the periphery thereof, and a charging agitator 18 is provided in a tank near the raw material charging section 17. A gas outlet 19 for discharging evaporated gas and an inspection hatch 20 for internal inspection are provided near the peripheral edge.
As shown in FIG. 2, when connecting the raw material transport pipe 17a and the decomposition / evaporation tank 2, the raw material charging section 17 interposes a rotary valve 17b, a three-way valve 17c, a water-cooled heat breaker 17d, and a catalyst transport screw. The pipe 21 is connected to a catalyst carrying pipe 21a in which the pipe 21 is loaded. The pulverized raw material from the raw material transfer pipe 17a is carried in by a predetermined flow rate by a highly hermetic rotary valve 17b to prevent air from entering from above, and the catalyst from the catalyst carry-in pipe 21a is carried in by the catalyst carry-in screw 21. Therefore, these are mixed and introduced into the decomposition evaporation tank 2. The water-cooled heat circuit breaker 17d circulates cold water inside, thereby suppressing the heat from the decomposition and evaporation tank 2 from being transmitted upward by water cooling. Further, the temperature rise of the rotary valve 17b is suppressed until the inside of the decomposition evaporator tank 2 rises to a predetermined temperature at the start of the operation and by closing the three valve 17c at the stop. The three-way valve 17c also closes when performing an emergency stop.

  A non-combustible gas supply pipe 22 for supplying non-combustible gas such as nitrogen gas is connected to the raw material transfer pipe 17a, and the non-combustible gas supply pipe 22 is connected to the discharge guide pipe 10 for discharging residues. Is also connected. The incombustible gas is supplied to shut off the inside of the decomposition evaporation tank 2 from the outside air, and is controlled to a pressure suitable for shutting off the outside air by using a pressure gauge.

The charging agitator 18 is configured as follows.
On the ceiling wall 3, a motor 23 is installed with a motor base 23 a with its shaft facing downward, and a stirring cylinder 24 installed in the decomposition evaporation tank 2 is provided with a stirring shaft by upper and lower bearings 25 a and 25 b. 26 is vertically supported, and a number of agitating blades 27a are protruded from the agitating shaft 26 substantially horizontally in multiple stages. 27b are provided in multiple stages. Then, the rotation of the motor 23 is transmitted to the stirring shaft 26 by the gear 28. A charging guide 29 is provided between the raw material charging section 17 and the stirring cylinder 24, and the pulverized raw material and the catalyst mixed and carried in as described above are supplied to the charging guide 29 (see FIG. 3). Guided into the stirring cylinder 24 and guided by the cooperation of a number of rotating stirring blades 27 a and a number of fixed stirring auxiliary blades 27 b, the stirring is performed onto the bottom inner plate 4 a at the peripheral portion in the decomposition evaporation tank 2 while being stirred. And fall. This stirring is performed at high speed by the high-speed rotation of the stirring shaft 26.
The reaction effect of the catalyst can be increased by introducing the catalyst using a stirrer at a plurality of locations separated in the circumferential direction of the decomposition evaporation tank 2.

The pulverized raw material and the catalyst that have fallen on the bottom inner plate 4a of the decomposing / evaporating tank 2 while being stirred in this way are subjected to the stirring and transfer action by the decomposing stirrer 30 provided in the decomposing / evaporating tank 2.
The decomposition agitator 30 has a stirring shaft 31 having an upper bearing 32 installed at the center of the ceiling wall 3 and a lower bearing 33 installed at the center of the bottom wall 4. The stirring support frame 34 is assembled in a cylindrical basket shape using the stirring shaft 31 as a support shaft, and the first stirring section and the second stirring section having different stirring modes are mounted on the stirring support frame 34. And a unit.

That is, the stirring support frame 34 includes upper and lower horizontal radiating frames 34a and 34b laid radially on the stirring shaft 31 by a plurality of upper and lower radiators, and upper and lower annular frames 34c and 34d laid on the tops of the upper and lower radiating frames, respectively. The plurality of vertical frames 34e provided between the upper and lower annular frames 34c and 34d form a cylindrical basket as a whole.
Then, a number of recirculating stirring blades 35 are provided on the lower annular frame 34d so as to protrude substantially horizontally at equal intervals in the circumferential direction, and each of the recirculating stirring blades 35 is reinforced by a diagonal member 36 for backup reinforcement. 1 constitutes the stirring section. Also, in this example, a number of converging stirring blades 37 are provided on each lower horizontal radiating frame 34b, which is eight, downward at a radial interval, and oblique to the radiation of each horizontal radiating frame 34b. The second stirrer is configured by being vertically installed at an angle and gradually changing the angle.
Each of the large number of recirculating stirring blades 35 extends near the inner surface of the bottom wall 5 (the upper surface of the bottom inner plate 4a) of the decomposition / evaporation tank 2 and near the inner peripheral surface of the peripheral wall 4 along the horizontal radiation. The large number of convergent stirring blades 37 in the frame 34b are farther from the stirring shaft 31 in accordance with the inclination, since the upper surface of the bottom inner plate 4a is an inclined surface that gradually rises toward the center as described above. It gets shorter as it gets closer.
The disengagement agitator 30 engages a driven gear 38a fixed to the agitating shaft 31 with a drive gear 38b on the motor 39 side installed on the ceiling wall 3 so as to be driven by the motor 39 in FIGS. It is rotated counterclockwise at low speed.
In addition, the screw shaft 12a of the above-described residue discharging screw 12 for discharging the residue is directly connected to the stirring shaft 31 of the decomposition stirrer 30, and the residue discharging screw 12 rotates at the same speed as the decomposition stirrer 30 at a low speed.

  When the decomposition stirrer 30 is rotated at a low speed in the counterclockwise direction by the motor 39, the pulverized raw material and the catalyst are fed counterclockwise on the bottom inner plate 4a while being stirred as described later in detail. As shown by the arrow in FIG. 5, at a position slightly closer to the clockwise direction than the raw material charging unit 17, the guide is turned to the inner peripheral surface of the peripheral wall 5 in order to guide the vehicle toward the center at a position substantially one round from the charging position. The guide plate 40 is fixed. The lower edge of the diverting guide plate 40 has a higher positional relationship than the recirculating agitating blade 35 so that the diverting guide plate 40 does not interfere with the decomposing stirrer 30. The transport stirring blade 35 passes below the lower edge of the deflection guide plate 40.

Next, a series of operations performed by the waste plastic decomposition apparatus 1 configured as described above will be described.
The pulverized raw material carried in from the rotary valve 17b and the catalyst carried in by the catalyst conveying screw 21 are stirred and mixed in the stirring cylinder 24 from the upper end to the lower end by the high-speed rotation of the charging stirrer 18 while the peripheral wall is closed. 5 is dropped onto the bottom inner plate 4a of the bottom wall 5 near the inner peripheral surface of the bottom wall 5. The pulverized raw material and the catalyst dropped here are slid on the upper surface of the bottom inner plate 4a by the first stirring section, that is, a large number of the forward stirring blades 35 arranged in the circumferential direction by the low-speed rotation of the decomposition stirrer 30. The mixture is agitated and sent counterclockwise to move.

  On the bottom wall 4 and the peripheral wall 5 of the decomposition evaporation tank 2, the heat medium heated outside flows through the cavities 7.8 and circulates, and heats the inside of the decomposition evaporation tank 2 from the bottom wall 4 and the peripheral wall 5 at a uniform temperature. Therefore, the pulverized raw material is heated with good thermal conductivity under uniform temperature conditions by being stirred and fed while repeating contact with the bottom wall 4 and contact with the inner peripheral surface of the peripheral wall 5. It reacts with the catalyst under such heating conditions, and the thermal decomposition proceeds uniformly with good thermal efficiency.

  The pulverized raw material whose thermal decomposition has progressed to some extent in this way and whose volume has been reduced is sent to the deflection guide plate 40, whereby the flow direction is changed toward the center of the decomposition evaporation tank 2. The pulverized raw material whose flow has been changed is dispersed so as to be separated by the second stirring section of the decomposition stirrer 30, that is, a large number of converging stirring blades 37 arranged in the radial direction, and spread on the bottom wall 4 and continuously stirred. However, since a large number of convergent stirring blades 37 are vertically suspended at a gradually changing angle with respect to the radiation in each horizontal radiation frame 34b as described above, the convergent stirring blades 37 gradually converge to the residue discharge section 11 while being heated. Go. The pulverized raw material has been thermally decomposed up to this point, and the remaining residue gradually falls into the discharge guide pipe 10 of the residue discharge section 11, where the residue is fed to the residue discharge screw 12 rotating at the same speed as the decomposition stirrer 30. However, since the outlet of the discharge guide tube 10 is closed by the on-off valve 14, the discharge guide tube 10 accumulates in the discharge guide tube 10. When the pushing force by the residue discharge screw 12 becomes larger than the spring force acting on the on-off valve 14, the on-off valve 14 is pushed open to discharge the accumulated residue. Since it is closed, heat loss due to residue discharge can be minimized. The residue discharged from the discharge guide tube 10 is collected through the residue transfer tube 10a.

On the other hand, since the upper surface of the bottom inner plate 4a of the bottom wall 4 is gently downwardly inclined from the center where the residue discharge portion 11 is located to the peripheral edge of the bottom wall 4, the oil generated by the thermal decomposition of the pulverized raw material is The gasification efficiency is increased because the pulverized raw material and the residue do not flow on the bottom inner plate 4a in the direction of the residue discharge unit 11 but flow in the opposite direction to the flow of the pulverized raw material and the residue that are moved to the center, that is, the flow is separated therefrom. At the same time, the residual oil content in the residue can be minimized. The gas evaporated in the decomposition evaporation tank 2 is discharged to the outside from the gas discharge port 19, and undergoes the next processing.
Since the waste plastic decomposition apparatus 1 can continuously perform the input of the pulverized raw material and the input of the catalyst while performing a series of operations after the input under the condition that the thermal decomposition process is sufficiently performed, In addition, the thermal decomposition treatment of the waste plastic can be continuously and efficiently performed without being interrupted every time the residue is discharged, and the decomposition capacity of the decomposition evaporation tank 2 can be increased in quantity to improve the processing capacity. The above-described processing in the decomposition evaporation tank 2 is performed in an oxygen-free state in which the outside air is always shut off.

  In the above-described first embodiment, the charging stirrer 18 and the decomposition stirrer 30 are individually driven in which the former is driven at high speed by the respective motors 23 and 39, and the latter is driven at low speed. As in the modified example shown, the motor 23 may be used in common, and the decomposing stirrer 30 may be of a deceleration transmission type via a deceleration mechanism. In this modification, a small gear 39a fixed to the stirring shaft 26 of the charging stirrer 18 and a large gear 39b fixed to the stirring shaft 31 of the decomposition stirrer 30 mesh with each other to form a reduction mechanism.

  Next, an embodiment of a waste plastic oiling system including such a waste plastic decomposition apparatus 1 will be described. FIG. 7 is a diagram showing the arrangement of devices on the machine frame 41, and FIG. 8 is a flow sheet of the entire system.

First, an arrangement relationship and a processing flow will be outlined with reference to FIG.
The pulverized raw material conveyed in the pipe by air is collected by the cyclone 42 and temporarily stored in the raw material input hopper 43, and the catalyst conveyed in the pipe is also temporarily stored in the catalyst input hopper 44. . Then, the pulverized raw material in the raw material input hopper 43 is sent out by the paddle screw conveyor 45 and taken over by the rotary valve 17b at a predetermined flow rate into the input stirrer 18, and at the same time, the catalyst in the catalyst input hopper 43 The conveyer screw 21 feeds into the charging stirrer 18, and drops on the bottom wall 4 of the decomposition evaporation tank 2 while being mixed and stirred by the charging stirrer 18 as described above. In order to efficiently perform such material introduction and catalyst introduction using its own weight, the material introduction hopper 43 and the catalyst introduction hopper 44 are installed above the decomposition and evaporation tank 2.
The thermal decomposition process in the decomposition evaporation tank 2 is as described in the first embodiment.

  The decomposed gas evaporated by the thermal decomposition in the decomposition and evaporation tank 2 is cooled by a first condenser 46 installed above the decomposition and evaporation tank 2 and connected to the gas outlet 19 by piping. This condenser 46 functions as a primary cracked oil generating device, and the primary cracked oil is generated by cooling here. This primary cracked oil falls into the distillation tank 48 of the distillation stabilizer 47 installed below the condenser 46 and connected to the piping.

  Since the distillation stabilizing device 47 employs the same heating method as the decomposition and evaporation tank 2, the distillation tank 48 has a double structure in which a bottom wall and a peripheral wall form a cavity, and a heating medium is circulated through the cavity to perform distillation. The inside of the tank 48 is heated indirectly. The heating temperature here is within a predetermined temperature range lower than the heating temperature in the decomposition evaporation tank 2. Further, in order to distill the primary cracked oil in the distillation tank 48 while stirring it, a stirrer 50a rotated by a motor 49 outside the tank is provided, but a simple structure is sufficient.

  The gas evaporated in the distillation tank 48 is cooled by a second condenser 51 installed above and connected to a pipe. The condenser 51 functions as a secondary cracked oil generator, and the secondary cracked oil is generated by cooling here. On the other hand, the primary cracked oil remaining in the distillation tank 48 accumulates in the distillation tank 48 by a certain amount because the distillation tank 48 and the decomposition evaporation tank 2 are connected by the return pipe 52 with the electromagnetic valve interposed. Is returned to the decomposition and evaporation tank 2, and is again subjected to thermal decomposition in the decomposition and evaporation tank 2.

  The secondary cracked oil generated in the second condenser 51 once flows into a separation tank 53 installed above and connected to a pipe to precipitate and separate impurities and the like, and then adjusts a flash point installed therebelow. It enters the constant temperature heating tank 55 of the device 54, where it is indirectly heated again by the heating medium. In the flash point adjusting device 54 as well, the secondary cracked oil in the constant temperature heating tank 55 is heated while being stirred by the stirrer 50b as in the distillation tank 48. The heating temperature of the constant temperature heating tank 55 is set to a substantially constant temperature lower than the heating temperature of the distillation tank 48. By heating at such a low and substantially constant temperature, a low carbon number of less than a certain value, that is, a material having a low flash point, evaporates. Therefore, the non-evaporated oil is stored in the product storage tank 56 as a target product oil. This tank 56 is protected by an oil barrier 57.

Next, a specific example of processing in each device will be described with reference to FIG.
Assuming that the waste plastic as a raw material is a mixture of three types of PP, PE, and PS, the forms include hard, soft, and film. The hard form is pulverized by the first pulverizer 58a, and the soft form or the film form is pulverized by the second pulverizer 58b. After heating at a low temperature to the extent that it does not undergo thermal decomposition, the volume is reduced, and then stored in the raw material storage tank 60A and naturally cooled.

  The stored pulverized raw material is transported through a pipe 62 by a blower 61, collected by the cyclone 42, and temporarily stored in a raw material input hopper 43. From the raw material charging hopper 43, the raw material is charged into the cracking and evaporating tank 2 of the waste plastic cracking device 1 having the structure shown in the first embodiment by the paddle screw conveyor 45. At the same time, the catalyst in the catalyst tank 60B is also charged into the decomposition and evaporation tank 2, and is stirred and mixed with the pulverized raw material in the decomposition and evaporation tank 2 as described above, and is thermally decomposed. For example, after being put into the decomposition evaporating tank 2, it is circulated and agitated by a number of circulating agitating blades 35, which are the first agitating sections of the agitator 30 for decomposition, and is diverted by the deflection guide plate 40 shown in FIG. The time required to be directed is about 1 hour, and the time required to converge to the residue discharge section 11 while being stirred by the plurality of converging stirring blades 37 as the second stirring section is about 2 hours. Pyrolysis is performed for a total of about 3 hours.

In this example, an FCC waste catalyst containing silica and alumina as main components is used as a catalyst to be reacted with the pulverized raw material for the following reasons.
(1) The FCC waste catalyst is a used FCC catalyst discharged from a refinery or the like, and is discharged at a large amount, so that it is much cheaper than a virgin FCC catalyst.
(2) Once used as a catalyst, it has deteriorated and the catalytic reaction during thermal decomposition has been reduced. The use of FCC spent catalysts, whereas the resulting regenerated oil is limited to petroleum products having carbon atoms of C9 or less, because pyrolysis tends to concentrate on small values generally having carbon atoms of less than C9. Because the reaction is reduced, it has the advantage that it can be regenerated not only as petroleum products with carbon number of 9 or less, but also as petroleum products with higher carbon number such as kerosene, and it is suitable for thermal decomposition at lower temperature, not at high temperature range That
(3) Since it is intended to economically and efficiently regenerate highly marketable petroleum products such as gasoline, kerosene, and gas oil having carbon number of 20 or less, silica and alumina are mainly used. The FCC spent catalyst remains at the time of thermal decomposition performed by indirect heating by the decomposition and evaporation tank 2 in the first stage, and after the operation is completed, the FCC spent catalyst remains at a high temperature and adheres. When the oil is to be evaporated and then discharged, there are advantages such as easy control of the heating temperature and easy disposal.
However, the present invention does not limit the use of virgin FCC catalysts.

  The pulverized raw material and the FCC waste catalyst are heated indirectly by the heat medium sent from the heat medium heater 60 while being stirred and transferred in the decomposition evaporation tank 2 as described above. The heating temperature is adjusted by detecting the temperature of the heat medium from the heat medium heater 60 by the temperature sensor 61 and controlling the flow rate by the flow control valve 62 according to the temperature. Is maintained in the range of 350C to 450C, preferably 380C to 400C. Within this temperature range, the FCC spent catalyst reacts with the pulverized raw material, which is waste plastic, and undergoes thermal decomposition. Since the FCC waste catalyst has a poorer reaction to plastics such as PP, PE, and PS than the virgin catalyst, pyrolysis occurs in a wide range of carbon numbers. The number is about C1 to C40. The residue discharged from the decomposition evaporation tank 2 as described above is collected in the residue collection tank 63.

The cracked gas having C1 to C40 discharged from the gas outlet 19 of the cracking and evaporating tank 2 is cooled by the first condenser 50 serving as a primary cracked oil generating device, and the primary cracked oil having C6 to C40 is converted into a primary cracked oil. Generated. The primary cracked oil flows into the distillation tank 48 of the distillation stabilizer 47 as it is, and the low-carbon-cracked gas (low-boiling-point hydrocarbon, so-called off-gas) having a carbon number C1 to C5 lower than this carbon number is directly sent to the distillation tank 48. It will be like passing through.
The distillation stabilizing device 47 is intended to distill the primary cracked oil to lower the high range of the carbon number range. Heat. That is, the temperature of the heat medium from the heat medium heater 60 is detected by the temperature sensor 64 and the flow rate is controlled by the flow rate control valve 65 in accordance with the detected temperature. When the temperature is adjusted to a low predetermined temperature, for example, the distillation properties of kerosene according to JIS standards, the temperature is maintained at about 270 ° C.
Under such conditions, those having a carbon number of more than C15 do not evaporate in the distillation tank 48, but those having a carbon number below C15 evaporate. The cracked oil having the carbon number C16 to C40 remaining in the distillation tank 48 is returned to the cracking and evaporating tank 2 and subjected to thermal cracking treatment again, thereby narrowing the range of the carbon number of the cracked oil to be generated. Therefore, by controlling the heating temperature in the distillation tank 48, distillation can be performed according to the carbon number of the target petroleum product.

The gas component evaporated in the distillation tank 48 is cooled by a second condenser 51 which is a secondary cracked oil generating device, and secondary cracked oil having C6 to C15 is generated. The low-carbon-number decomposition gas (off-gas) of the number C1 to C5 remains unchanged here. The secondary cracked oil from the second condenser 51 is separated into impurities and the like in a separation tank 53 and then sent to a constant temperature heating tank 55 of a flash point adjusting device 54.
On the other hand, the low-carbon-decomposed gas (off-gas) having 1 to 5 carbon atoms that has passed through the separation tank 53 as it is is highly flammable. Send and use as gaseous fuel.

  The flash point adjusting device 57 heats with a heat medium in the same manner as described above, but heats the secondary cracked oil from the viewpoint of flash point adjustment, that is, sets the flash point of the secondary cracked oil in the constant temperature heating tank 55 to a certain temperature or higher. Therefore, the temperature of the heat medium from the heat medium heater 60 is detected by the temperature sensor 66, and the flow rate is controlled by the flow rate control valve 67 in accordance with the temperature, thereby heating at a constant temperature. For example, when the flash point is 30 ° C., if the temperature is based on 126 ° C., which is the boiling point of carbon number C8, those having a carbon number within the range of C9 to C15 remain in the constant temperature heating tank 55, and carbon Cracked oils of numbers C6 to C8 are separated. Since the decomposed oil having carbon atoms of C6 to C8 has a relatively high flash point, it can be used as a liquid fuel for the heat medium heater 60, but may be collected separately.

The produced oil having carbon number C9 to C15 remaining in the constant temperature heating tank 55 is timely fed into the product storage tank 56 by the pump 68 and stored therein. This produced oil becomes kerosene which is a highly marketable petroleum product having a carbon number in the range of C9 to C15.
It is clear that other petroleum products such as light oil and heavy oil having different carbon numbers can be produced by adjusting the heating temperature in the distillation tank 48 and the heating temperature in the constant temperature heating tank 55 in the same manner as the temperature adjustment. .

  The present invention can be applied not only to a case where waste plastic such as PP, PE, and PS is used as a raw material, but also to a case where waste oil is used as a raw material.

DESCRIPTION OF SYMBOLS 1 Waste plastic decomposition apparatus 2 Decomposition evaporating tank 3 Ceiling wall 4 Bottom wall 4a Bottom inner plate 4b Bottom outer plate 5 Peripheral wall 5a Inner peripheral plate 5b Outer peripheral plate 6 Insulation material 7 Cavity 8 Cavity 9 Rib 10 Discharge guide tube 11 Residue discharge part ( Residue discharge port)
Reference Signs List 12 Residue discharge screw 12a Screw shaft 13 Valve cylinder 14 Open / close valve 15 Heat medium introduction pipe 16 Heat medium discharge pipe 17 Raw material charging section 17a Raw material transport pipe 17b Rotary valve 17c Release valve 17d Water-cooled heat breaker 18 Charging stirrer 19 Gas Discharge port 20 Inspection hatch 21 Catalyst carrying screw 21a Catalyst carrying pipe 22 Noncombustible gas supply pipe 23 Motor 24a Motor base 24 Stirrer cylinder 25a / 25b Bearing 26 Stirrer shaft 27a Stirrer 24b Stirrer auxiliary blade 28 Gear 29 Input guide 30 Stirring for disassembly Machine 31 Stirring shaft 32 Upper bearing 33 Lower bearing 34 Stirring support frame 34a / 34b Horizontal radiating frame 34c / 34d Annular frame 34e Vertical frame 35 Forward stirring blade 36 Backup diagonal material 37 Converging stirring blade 38a Drive gear 38b Drive gear 39a Small gear 39b Large gear 40 Deflection The inner plate 41 device frame 42 cyclone 43 feed hopper 44 catalyst hopper 45 paddle screw conveyor 46 capacitor (primary cracked oil generator)
47 Distillation stabilizer 48 Distillation tank 49 Motor 50a / 50b Stirrer 51 Condenser (secondary cracked oil generator)
52 Distillation tank 53 Separation tank 54 Flash point adjuster 55 Constant temperature heating tank 56 Product storage tank 57 Flash point adjuster 58a / 58b Crusher 59 Volume reducer 60A Raw material storage tank 60B Catalyst tank 61 Temperature sensor 62 Flow control valve 63 Residue recovery Tank 64 Temperature sensor 65 Flow control valve 66 Temperature sensor 67 Flow control valve 68 Pump 69 Gas cleaning device 70 Vacuum pump

Claims (2)

In the heated drum-type decomposition / evaporation tank, a decomposition stirrer rotated by an external motor is provided, and is rotated simultaneously with the decomposition stirrer and discharged from the bottom center of the decomposition / evaporation tank through a discharge guide tube. It is provided with a residue discharge screw for discharging the residue, and the agitation material for stirring and the catalyst fed into the decomposition and evaporation tank are converged to the center of the bottom while being stirred on the bottom of the decomposition and evaporation tank. Waste plastic decomposition equipment equipped with a number of stirring blades,
A primary cracked oil generating device that cools a gas component evaporated from the cracking and evaporation tank to generate a primary cracked oil,
A distillation stabilizing device that evaporates the primary cracked oil by heating it within a predetermined temperature range lower than the waste plastic cracking device in the distillation tank and returns residual oil to the cracking and evaporation tank,
A secondary cracked oil generating device that generates a secondary cracked oil having a carbon number of not more than a predetermined number by cooling a gas component evaporated from the distillation stabilizer,
A flash point adjusting device that heats the secondary cracked oil in a constant temperature heating tank while maintaining it at a substantially constant temperature lower than the heating temperature of the secondary cracked oil generating device, and performs evaporation at that temperature,
A waste plastic oiling system comprising:   2. The waste plastic oil liquefaction system according to claim 1, wherein an open / close valve that is opened by the residue pushing force of the discharge screw is provided on the discharge guide tube. 3.

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