JP4040836B2 - Waste plastic processing equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a waste plastic processing apparatus that thermally decomposes and processes waste plastic.
[0002]
[Prior art]
In general, waste plastic is melted in a desalting apparatus, desalted, and transferred to a melting tank. In the melting tank, the molten plastic is stirred while being heated, and the desalted gas is efficiently released. Thereafter, the molten plastic that has been desalted substantially completely is transferred to the thermal decomposition apparatus via a discharge mechanism provided in the melting tank.
[0003]
The thermal decomposition apparatus thermally decomposes molten plastic to generate oil gas and residue. The oil gas is produced as a product oil by a product oil recovery tower or the like and reused as fuel. The residue is collected in a residue collection container and is also reused as solid fuel or the like.
[0004]
[Problems to be solved by the invention]
When discharging the residue, the residue needs to be cooled to a temperature that does not ignite even when the residue comes into contact with the atmosphere. The ignition of the residue is extremely dangerous because it can cause a fire or explosion.
[0005]
On the other hand, the discharge of the residue from the thermal decomposition apparatus is preferably performed as fast as possible from the viewpoint of improving the efficiency of waste plastic treatment.
[0006]
The present inventor has developed a configuration in which a residue storage hopper that temporarily stores and cools the residue discharged from the thermal decomposition apparatus is provided, and the residue storage hopper functions as a buffer for residue cooling. In this case, the residue can be efficiently cooled and the residue can be efficiently discharged (conveyed) from the thermal decomposition apparatus.
[0007]
However, the cooling of the residue in the residue storage hopper can lead to a decrease in pressure in the residue storage hopper. And the fall of the pressure in a residue storage hopper can cause destruction of a residue storage hopper. The destruction of the residue storage hopper can lead to a fire or explosion caused by residues that are not sufficiently cooled coming into contact with the atmosphere.
[0008]
The present invention has been made in consideration of such points, and provides a waste plastic processing apparatus that can reliably prevent the destruction of a residue storage hopper and avoid the occurrence of a fire or an explosion. It shall be the purpose.
[0009]
[Means for Solving the Problems]
The present invention comprises a pyrolysis device for discharging the residue by thermal decomposition, are connected via a closed conveyor device to the thermal decomposition apparatus, and the remaining渣貯fraction hopper for temporarily storing the residue is discharged from the pyrolysis apparatus , A storage residue cooling mechanism for cooling the residue stored in the residue storage hopper, an inert gas supply mechanism for supplying inert gas to the residue storage hopper, and a state quantity in the residue storage hopper A waste plastic processing apparatus comprising: a detector; and a control unit that controls the inert gas supply mechanism based on a detection value of the detector.
[0010]
According to the present invention, the inert gas supply mechanism is controlled based on the detection value by the detector, so that the inert gas is introduced into the residue storage hopper according to the change in the state quantity in the residue storage hopper. Thus, fluctuations in the internal pressure of the residue storage hopper are suppressed, and as a result, destruction of the residue storage hopper is prevented. In addition, since the residue storage hopper is connected to the thermal decomposition apparatus via a hermetic conveyor device, it is possible to avoid the occurrence of fire and explosion.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
An embodiment of a waste plastic processing apparatus according to the present invention will be described below with reference to FIG.
[0014]
As shown in FIG. 1, a waste plastic processing apparatus 1 according to the present embodiment includes a melting tank 11 in which desalted plastic is melted, and a thermal decomposition apparatus connected to a discharge port 11a of the melting tank 11 via a valve 11v. 12 . The thermal decomposition apparatus 12 thermally decomposes molten plastic to generate oil gas and residue .
[0015]
The oil gas is sent to a product oil recovery mechanism (not shown) through the gas discharge port 12a of the thermal decomposition apparatus 12.
[0016]
The residue is sent to a residue storage hopper 30 to be described later via a residue discharge port 12b of the thermal decomposition apparatus 12.
[0017]
The residue discharge port 12b of the thermal decomposition apparatus 12 is connected to the input port 20a of the conveyor apparatus 20 which conveys a residue toward the residue storage hopper 30 via the valve 12v. In this case, the conveyor device 20 is a sealed conveyor device having a sealed wall 20w.
[0018]
The discharge port 20b of the conveyor device 20 is connected to the input port 30a of the residue storage hopper 30 through a valve 20v. In this case, the residue storage hopper 30 is a substantially cylindrical hermetic hopper. The bottom surface portion of the residue storage hopper 30 is inclined in a funnel shape, and communicates with the discharge pipe 35 at the lowermost portion. That is, the central axis of the residue storage hopper 30 and the central axis of the discharge pipe 35 substantially coincide with each other.
[0019]
A rotary screw 30 s is disposed so as to be rotatable about the axis along the central axis of the residue storage hopper 30 (the central axis of the discharge pipe 35). The tip of the rotary screw 30 s reaches the inside of the discharge pipe 35. On the other hand, the base end of the rotary screw 30s is connected to a rotary motor 30m, and is rotated in both forward and reverse directions around the axis by the rotary motor 30m.
[0020]
The rotating screw 30 s has a screw part formed at least in a portion corresponding to the lower part of the residue storage hopper 30. Thereby, the rotating screw 30s discharges the residue so as to be sent out during the forward rotation, and holds the residue in the residue storage hopper 30 during the reverse rotation.
[0021]
Further, a stirring blade 30f is attached to the rotary screw 30s so as to be separated from the inner surface of the residue storage hopper 30 by a minute distance. Accordingly, the stirring blade 30f effectively stirs the residue in the residue storage hopper 30 with the rotation of the rotary screw 30s.
[0022]
Further, a storage residue cooling jacket 31 is provided around the side surface and the lower surface of the residue storage hopper 30. Cooling water is introduced into the storage residue cooling jacket 31. In this case, as shown in FIG. 1, the cooling water is preferably configured to flow from the downstream side toward the upstream side in the moving direction of the residue.
[0023]
In addition, the residue storage hopper 30 is provided with a cooling nozzle 33 for injecting cooling water into the residue storage hopper 30 to directly cool the residue. Further, the residue storage hopper 30 is provided with an inert gas supply mechanism 34 for introducing an inert gas into the residue storage hopper 30.
[0024]
Further, the residue storage hopper 30 is provided with a detector 30t for detecting an internal state quantity. This detector is in this case a pressure gauge.
[0025]
The control unit 50 is connected to the detector 30t. The control unit 50 is connected to the valve 34v of the inert gas supply mechanism 34 and the like, and supplies an inert gas to the inside of the residue storage hopper 30 based on the detection value of the detector 30t.
[0026]
A residue collection container 40 is connected to the discharge pipe 35 of the residue storage hopper 30 via a residue discharge valve 30v and a removable bellows 30j.
[0027]
The residue collection container 40 is also provided with an inert gas supply mechanism 44 for introducing an inert gas into the residue collection container 40. Further, the residue collection container 40 is also provided with a detector 40t for detecting the internal state quantity. This detector is also a pressure gauge in this case.
[0028]
And the control part 60 is connected to the detector 40t. The control unit 60 is connected to the valve 44v of the inert gas supply mechanism 44 and the like, and supplies an inert gas into the residue collection container 40 based on the detection value of the detector 40t.
[0029]
In addition, in order to purge the inert gas in the residue collection container 40, a residue bag filter 40f and an inert gas purge nozzle 40n are provided via a bellows 40j and a purge valve 40v.
[0030]
Next, the operation of the waste plastic processing apparatus 1 according to this embodiment will be described.
[0031]
First, desalted plastic desalted by a desalting apparatus (not shown) is supplied into the melting tank 11 and melted. Then, the molten plastic is introduced into the thermal decomposition apparatus 12 through the discharge port 11a and the valve 11v of the melting tank 11. The thermal decomposition apparatus 12 thermally decomposes the molten plastic to generate a residue with oil gas.
[0032]
The oil gas generated by the thermal decomposition is sent to a generated oil recovery mechanism (not shown) through the gas discharge port 12a of the thermal decomposition apparatus 12, and is reused as the generated oil.
[0033]
On the other hand, the residue generated by the thermal decomposition is sent to the charging port 20a of the hermetic conveyor device 20 through the residue discharge port 12b and the valve 12v of the thermal decomposition device 12. The sealed conveyor device 20 conveys the residue supplied to the input port 20 a to the discharge port 20 b of the conveyor device 20.
[0034]
The residue conveyed to the discharge port 20b of the conveyor device 20 is sent to the input port 30a of the residue storage hopper 30 via the valve 20v. The residue storage hopper 30 temporarily stores the residue supplied from the charging port 30a.
[0035]
During the temporary storage of the residue, if necessary, the rotary screw 30s is reversely rotated to stir the residue.
[0036]
Further, during the temporary storage of the residue, the cooling water is supplied to the storage residue cooling jacket 31. Thereby, a residue is cooled efficiently. Furthermore, cooling water is injected from the cooling nozzle 33 into the residue storage hopper 30 to directly cool the residue.
[0037]
By cooling the residue as described above, the pressure inside the residue storage hopper 30 can be reduced. In the present embodiment, when the detector 30t detects that the pressure inside the residue storage hopper 30 has become a specified value or less in order to prevent the generation of such negative pressure, the control unit 50 performs the inert gas supply mechanism 34. And an inert gas is supplied into the residue storage hopper 30. At this time, the supply amount of the inert gas may be set corresponding to the detection value of the detector 30t.
[0038]
Thereafter, for example, when the residue in the residue storage hopper 30 is sufficiently cooled, the rotary screw 30s rotates forward and the residue discharge valve 30v is opened, and the residue is discharged into the residue collection container 40.
[0039]
The discharged residue is cooled also in the residue collection container 40 due to a difference between a cooling mechanism (not shown) and an outside temperature. Along with this, the internal pressure of the residue collection container 40 may decrease. In the present embodiment, when the detector 40t detects that the pressure inside the residue collection container 40 has become a specified value or less in order to prevent the generation of such negative pressure, the control unit 60 performs the inert gas supply mechanism 44. And the inert gas is supplied into the residue collection container 40. At this time, the supply amount of the inert gas may be set corresponding to the detection value of the detector 40t.
[0040]
Conversely, the excess inert gas is discharged from the inert gas purge nozzle 40n via the residue bag filter 40f.
[0041]
As described above, according to the present embodiment, the inert gas supply mechanism 34 is controlled based on the detection value by the detector 30t, and the residue storage hopper 30 according to the change in the state quantity inside the residue storage hopper 30. Since the inert gas is introduced into the inside, fluctuations in the internal pressure of the residue storage hopper 30 are suppressed, and as a result, destruction of the residue storage hopper 30 is prevented.
[0042]
Accordingly, for example, the upstream and downstream valves of the residue storage hopper 30 are closed (except for the valve 34v of the inert gas supply mechanism 34), and the residue is cooled so that external air does not enter the residue storage hopper 30. Even in the case of performing the above, it is possible to prevent the residue storage hopper 30 from being in an extremely negative pressure state.
[0043]
In addition, according to the present embodiment, the inert gas supply mechanism 44 is controlled based on the detection value by the detector 40t, and the inside of the residue collection container 40 is changed according to the change in the state quantity inside the residue collection container 40. Since the inert gas is introduced, fluctuations in the internal pressure of the residue collection container 40 are suppressed, and as a result, destruction of the residue collection container 40 is prevented.
[0044]
Furthermore, since cooling water is injected from the cooling nozzle 33 and the residue is directly cooled, a sufficient cooling effect is obtained. Such cooling water injection also has an effect of preventing the residue to be discharged from staying in the residue storage hopper 30.
[0045]
Moreover, since the residue storage hopper 30 functions as a buffer for residue cooling, the discharge and conveyance of the residue from the thermal decomposition apparatus 12 can be performed with extremely high efficiency (high speed).
[0046]
In addition to the pressure gauge, a thermometer or an oxygen concentration meter can be adopted as the detector 30t. Furthermore, it is preferable that these detectors are provided at the same time and the inert gas supply mechanism 34 is controlled by fusing detection values from a plurality of detectors.
[0047]
Similarly, as the detector 40t, a thermometer or an oxygen concentration meter can be adopted in addition to a pressure gauge. And it is preferable to provide these detectors simultaneously and to control the inert gas supply mechanism 44 by fusing detection values from a plurality of detectors.
[0048]
【The invention's effect】
As described above, according to the present invention, by controlling the inert gas supply mechanism based on the detection value by the detector, the inside of the residue storage hopper according to the change in the state quantity inside the residue storage hopper. Inert gas is introduced to the inside, and the fluctuation of the internal pressure of the residue storage hopper is suppressed, so that the residue storage hopper is prevented from being destroyed. In addition, since the residue storage hopper is connected to the thermal decomposition apparatus via a hermetic conveyor device, it is possible to avoid the occurrence of fire and explosion.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a waste plastic processing apparatus showing an embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Waste plastic processing apparatus 11 Melting tank 11a Discharge port 11v Valve 12 Thermal decomposition apparatus 12a Gas discharge port 12b Residue discharge port 12v Valve 20 Conveyor device 20a Input port 20b Discharge port 20w Sealed wall 30 Residue storage hopper 30a Input port 30s Rotating screw 30m Rotating motor 30f Stirring blade 30v Residue discharge valve 30j Bellows 30t Detector 31 Storage residue cooling jacket 33 Cooling nozzle 34 Inert gas supply mechanism 34v Valve 35 Discharge pipe 40 Residue collection container 40j Bellows 40v Purge valve 40f Residual bug filter 40n Active gas purge nozzle 44 Inert gas supply mechanism 44v Valve 50 Control unit 60 Control unit

Claims (3)

A pyrolysis device for pyrolyzing and discharging the residue ;
A residue storage hopper connected to the pyrolysis device via a hermetic conveyor device and temporarily storing the residue discharged from the pyrolysis device;
A storage residue cooling mechanism for cooling the residue stored in the residue storage hopper;
An inert gas supply mechanism for supplying an inert gas into the residue storage hopper;
A detector for detecting a state quantity inside the residue storage hopper;
A control unit for controlling the inert gas supply mechanism based on a detection value by the detector;
A waste plastic processing apparatus comprising: 2. The control unit according to claim 1, wherein the control unit controls the inert gas supply mechanism so that the internal pressure of the residue storage hopper becomes substantially constant based on a detection value by the detector. Waste plastic processing equipment. The waste plastic processing apparatus according to claim 1 or 2, wherein the storage residue cooling mechanism has a storage residue cooling jacket provided around the residue storage hopper.

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