Thermal decomposition system and waste plastic thermal decomposition system

Abstract

The present invention makes it possible to efficiently replace a residue tank (102). A thermal decomposition system (10) is provided with an extruder (12), a buffer chamber (26), a flow path section (52), a residue tank (102), and a conveyance section (72). The extruder (12) thermally decomposes the waste plastic (P). The buffer chamber (26) accommodates the residue (R) after thermal decomposition. The flow path portion (52) receives the residue (R) from the buffer chamber (26). The residue tank (102) collects the residue (R) discharged from the flow path part (52). The conveyance unit (72) conveys the residue (R) received from the buffer chamber (26) toward the residue tank (102).

Description

Technical Field

[0001] The present disclosure relates to a thermal decomposition system and a thermal decomposition system for waste plastics. Background Art

[0002] An extruder for thermally decomposing a polymer is disclosed in Patent Document 1.

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-127346 Summary of the Invention

[0006] Problems to be Solved by the Invention

[0007] Since residues are generated when a polymer is thermally decomposed by an extruder, a residue box is required to recover the residues. Therefore, means for improving the efficiency of residue recovery are required.

[0008] Other problems and new features can be understood from the description of this specification and the drawings.

[0009] Means for Solving the Problems

[0010] A thermal decomposition system according to one embodiment includes: a flow path unit that receives residues from a storage unit; a recovery unit that recovers the residues discharged from the flow path unit; and a transfer unit that transfers the residues received from the storage unit toward the recovery unit.

[0011] A thermal decomposition system for waste plastics according to one embodiment includes: a first extruder capable of thermally decomposing waste plastics; a second extruder into which residues discharged from the first extruder are introduced; and a recovery unit that can be detached from and attached to the second extruder and recovers the residues.

[0012] Advantages of the Invention

[0013] According to one embodiment of the present application, the residue recovery unit can be replaced efficiently.

[0014] According to other embodiments of the present application, the residue recovery unit can be replaced efficiently. Brief Description of the Drawings

[0015] Figure 1 It is an explanatory diagram showing the overall configuration of the thermal decomposition system according to the first embodiment.

[0016] Figure 2 It is shown by Figure 1 the thermal decomposition system to recover the residue state explanatory diagram.

[0017] Figure 3 is a cross-sectional view showing a state in which a waste object is discharged from a discharge die of a recycling machine Figure 1 as shown.

[0018] Figure 4 is an explanatory view showing Figure 1 the structure of a residue box used in a thermal decomposition system

[0019] Figure 5 is an explanatory view showing a residue box and a switching valve of the thermal decomposition system according to the second embodiment.

[0020] Figure 6 is an explanatory view showing a state in which residues are recovered by the thermal decomposition system according to the third embodiment.

[0021] Figure 7 is a cross-sectional view showing a state in which a waste object is recovered into an upstream-side box which is a modified example of a thermal decomposition system Figure 1 as shown. DETAILED DESCRIPTION OF THE INVENTION

[0022] 〔First Embodiment〕

[0023] Hereinafter, a thermal decomposition system 10 according to a first embodiment of the present disclosure will be described based on the drawings.

[0024] As Figure 1 shown, the thermal decomposition system 10 includes an extruder 12, a buffer chamber 26, a pipe 36, a drain tank 42, a heat exchanger 44, a recycling machine 50, and a residue box 102.

[0025] The thermal decomposition system 10 is provided on a floor 2 of a factory. Hereinafter, it is assumed that the floor 2 is a horizontal plane to define each direction and describe the arrangement of each component. The thermal decomposition system 10 is also an example of a thermal decomposition system for waste plastics.

[0026] <Extruder>

[0027] The extruder 12 is an example of a thermal decomposition device for thermally decomposing waste plastics P. The waste plastics P are an example of a resin material. The extruder 12 includes a hopper 13, a cylinder 14, a screw 16, a drive mechanism unit 18, and an extruder control unit 22. The extruder 12 thermally decomposes the waste plastics P and extrudes them. It should be noted that in the following description, the transport direction of the residue R described later is set as the Y direction. The Y direction is a horizontal direction. The base end side of the arrow Y corresponds to the upstream side. The front end side of the arrow Y corresponds to the downstream side.

[0028] The vertical direction orthogonal to the conveying direction and parallel to the vertical direction is set as the Z direction. The base end side of the arrow Z corresponds to the lower side. The tip end side of the arrow Z corresponds to the upper side. The left-right direction orthogonal to both the conveying direction and the vertical direction is set as the X direction. The X direction is the horizontal direction. When viewed from the upstream side of the conveying direction, the base end side of the arrow X corresponds to the left side of the extruder 12. When viewed from the upstream side of the conveying direction, the tip end side of the arrow X corresponds to the right side of the extruder 12.

[0029] The hopper 13 is connected to the cylinder block 14. The hopper 13 can supply the waste plastic P into the interior of the cylinder block 14. Examples of the waste plastic P include plastic products discarded after use in ordinary households, etc., and plastic waste generated during the manufacturing process of plastic products (parts that cannot be used as products).

[0030] The cylinder block 14 includes a plurality of cylinder blocks. The plurality of cylinder blocks are arranged and connected from the upstream side to the downstream side of the conveying direction. A heater 15 is provided on the outer peripheral portion of the cylinder block 14. A discharge pipe 24 is connected to the downstream end of the cylinder block 14.

[0031] The heater 15 is controlled by the extruder control unit 22 for the heating temperature. The heater 15 can heat the waste plastic P inside the cylinder block 14. Specifically, the heater 15 heats the waste plastic P via the cylinder block 14 to thermally decompose the waste plastic P.

[0032] The screw 16 is rotatably provided inside the cylinder block 14. As an example, two screws 16 are arranged in the left-right direction. That is, the extruder 12 is a twin-screw extruder. The two screws 16 are arranged to mesh with each other.

[0033] The drive mechanism unit 18 includes a motor. The drive mechanism unit 18 rotates the two screws 16. By rotating the two screws 16, the waste plastic P is kneaded and conveyed to the downstream side of the conveying direction.

[0034] The extruder control unit 22 includes a CPU (Central Processing Unit), a memory, and a storage. The extruder control unit 22 controls the operations of the heater 15 and the drive mechanism unit 18 by the CPU executing the program stored in the memory. That is, the extruder control unit 22 can control the temperature of the waste plastic P located inside the cylinder block 14 and the conveying speed (extrusion speed) of the waste plastic P. It should be noted that the waste plastic P is continuously thermally decomposed by the shear heat generated by the screw 16 and the heating by the heater 15.

[0035] As Figure 2As shown, the discharge pipe 24 is bent into an L shape. The discharge pipe 24 has a horizontal portion 24A extending along the conveying direction from the cylinder block 14 and a vertical portion 24B extending downward in the vertical direction from the downstream end of the horizontal portion 24A. A part of the horizontal portion 24A and the vertical portion 24B are disposed inside the buffer chamber 26.

[0036] <Buffer Chamber>

[0037] The buffer chamber 26 is an example of a housing portion that houses the residue R discharged from the extruder 12. The residue R will be described later. It should be noted that, in the present embodiment, as an example, the buffer chamber 26 is included in a part of the extruder 12 for description, but the buffer chamber 26 may not be included in a part of the extruder 12.

[0038] The buffer chamber 26 has a cylindrical portion 27, a sealing portion 32, and a cover portion 34. The cylindrical portion 27 is formed in a rectangular tube shape with openings at the upper and lower ends in the vertical direction. The cylindrical portion 27 includes side walls 28 and 29. A through hole 28A penetrating the side wall 28 in the conveying direction is formed in the side wall 28. The horizontal portion 24A is inserted into the through hole 28A. A nozzle 48 is provided on the side wall 29. The nozzle 48 injects nitrogen supplied from the nitrogen supply portion 46 into the inside of the buffer chamber 26. By injecting nitrogen into the inside of the buffer chamber 26, a quality deterioration caused by oxidation of the recycled material or the like is suppressed.

[0039] As an example, the sealing portion 32 is formed of a corrugated rubber member and can expand and contract in the conveying direction. The sealing portion 32 seals the gap at the edge between the horizontal portion 24A and the through hole 28A. When the relative position between the discharge pipe 24 and the buffer chamber 26 is displaced, by the elongation or contraction of the sealing portion 32, it is difficult to generate a gap between the discharge pipe 24 and the buffer chamber 26.

[0040] The cover portion 34 seals the upper end portion of the cylindrical portion 27 in the vertical direction. A gas discharge port 34A penetrating the cover portion 34 in the vertical direction is formed in a part of the cover portion 34. In other words, the extruder 12 has a gas discharge port 34A. The gas G generated by the thermal decomposition of the waste plastic P is discharged from the gas discharge port 34A. A pipe 36 described later is connected to a portion of the cover portion 34 that is downstream of the gas discharge port 34A. In the present embodiment, as an example, the entire lower end portion of the cylindrical portion 27 in the vertical direction is open to a heating jacket 54 described later.

[0041] The residue R is generated by the thermal decomposition of the waste plastic P. Specifically, by the thermal decomposition of the waste plastic P, the mixture M is discharged into the inside of the buffer chamber 26. The mixture M refers to a substance having at least two of the gas G, the liquid Q, and the solid S.

[0042] Residue R refers to the substances in mixture M other than gas G. In this embodiment, as an example, residue R is solid S or liquid Q. It should be noted that residue R can also be solid S and liquid Q. In addition, when waste plastic P contains foreign substances different from the object to be recycled, the substances generated from such foreign substances by thermal decomposition are included in residue R.

[0043] <Piping>

[0044] One end of piping 36 is connected to the edge of gas discharge port 34A. The other end of piping 36 is connected to a drainage tank 42 described later. Drainage tank 42 is connected to a heat exchanger 44 described later. The volume of gas G in heat exchanger 44 decreases due to the condensation of gas G (condensation vacuum is generated), whereby the inside of piping 36 becomes a negative pressure state. Therefore, even without using a vacuum pump, gas G inside buffer chamber 26 will flow through piping 36 to drainage tank 42 and heat exchanger 44. It should be noted that when a vacuum pump is used for the purpose of actively decompressing the inside of piping 36, the vacuum pump can be arranged at a position downstream of heat exchanger 44 or upstream of drainage tank 42.

[0045] <Drainage Tank and Heat Exchanger>

[0046] In drainage tank 42, the moisture (drainage) contained in gas G is recovered. Gas G after the moisture is recovered is sent to heat exchanger 44. In heat exchanger 44, gas G sent from drainage tank 42 is cooled. As an example, the cooling of gas G is performed by water cooling. Gas G inside heat exchanger 44 is condensed by cooling, thereby becoming liquid substance N. When monomer is contained in the recovered liquid substance N, the monomer can be polymerized in other devices and reused as a polymer.

[0047] <Recycling Machine>

[0048] Recycling machine 50 is an example of an extruder. The thermally decomposed residue R discharged from extruder 12 is put into recycling machine 50. As an example, recycling machine 50 includes a flow path section 52, a conveying section 72, a temperature adjustment section 82, an upstream discharge section 92, and a recycling machine control section 98.

[0049] (Flow Path Section)

[0050] The flow path portion 52 is a cylinder extending in the conveying direction. An inlet 53 is formed in a part on the upstream side and the upper part in the vertical direction of the flow path portion 52. The inlet 53 is a through hole that penetrates the wall portion 55 described later in the vertical direction. The lower end portion in the vertical direction of the buffer chamber 26 is attached to the edge portion of the inlet 53. Thus, the residue R inside the buffer chamber 26 falls into the inside of the flow path portion 52 through the inlet 53. In other words, the flow path portion 52 receives the residue R from the buffer chamber 26. In addition, the flow path portion 52 includes a heating jacket 54 and a cooling jacket 58.

[0051] The portion of the flow path portion 52 closer to the upstream side than the center becomes the heating jacket 54. The heating jacket 54 includes a cylindrical wall portion 55 and a flange 56 that extends outward from the downstream end portion of the wall portion 55. The inside of the wall portion 55 becomes the upstream flow path 57.

[0052] The portion of the flow path portion 52 closer to the downstream side than the center becomes the cooling jacket 58. The cooling jacket 58 includes a cylindrical wall portion 59 and a flange 61 that extends outward from the upstream end portion of the wall portion 59. A heat insulating member 71 is sandwiched between the flange 61 and the flange 56. In addition, the flange 61 is connected to the flange 56. By having the heat insulating member 71, heat exchange between the flange 61 and the flange 56 is suppressed, so that unnecessary energy consumption due to heating of the heating jacket 54 and cooling of the cooling jacket 58 can be suppressed.

[0053] The inside of the wall portion 59 becomes the downstream flow path 62. The upstream flow path 57 and the downstream flow path 62 have the same flow path cross-sectional area and are connected. A residue discharge port 63 is formed in a part on the downstream side and the lower part in the vertical direction of the wall portion 59.

[0054] As Figure 4 shown, a discharge pipe 64 is provided on the wall portion 59. The discharge pipe 64 extends downward in the vertical direction from the edge portion of the residue discharge port 63 of the wall portion 59. The discharge pipe 64 has an outer peripheral surface 64A. A slit 64B that penetrates the discharge pipe 64 in the conveying direction is formed in a part of the discharge pipe 64.

[0055] The inside of the discharge pipe 64 becomes the discharge flow path 65. The discharge flow path 65 is connected to the downstream flow path 62. A mounting / demounting portion 66 is provided at the lower end portion in the vertical direction of the discharge pipe 64. In other words, the flow path portion 52 has a mounting / demounting portion 66.

[0056] As an example, the mounting / demounting portion 66 includes two contact portions 68 provided on the outer peripheral surface 64A. The contact portion 68 has a transverse wall 68A that extends from the outer peripheral surface 64A along the conveying direction and a longitudinal wall 68B that extends downward in the vertical direction from the front end portion of the transverse wall 68A.

[0057] In the mounting / demounting section 66, the residue box 102 is mounted by moving the flange 114 described later to the left in the left-right direction and bringing the two contact portions 68 into contact with the flange 114. Further, in the mounting / demounting section 66, the residue box 102 is detached by pulling the flange 114 to the right in the left-right direction and causing the flange 114 to retreat from the two contact portions 68.

[0058] A slide gate 69 is provided at a position of the discharge pipe 64 that is above the mounting / demounting section 66. As an example, the slide gate 69 includes a flat plate sized to be able to close the discharge flow path 65. The slide gate 69 is supported by the edge portion of the slit 64B and can reciprocate in the conveying direction.

[0059] The slide gate 69 closes the discharge flow path 65 by moving toward the upstream side in the conveying direction. Further, the slide gate 69 opens the discharge flow path 65 by moving toward the downstream side in the conveying direction. The operation of the slide gate 69 can be either a manual operation performed by the operator H( Figure 2 ) or an automatic operation performed by a driving device such as a motor.

[0060] (Conveying section)

[0061] As Figure 2 shown, the conveying section 72 conveys the residue R received from the buffer chamber 26 toward the residue box 102 described later. As an example, the conveying section 72 includes two screws 74 extending in the conveying direction, a reverse screw 75, and a driving section 76. It should be noted that Figure 2 only one screw 74 is shown in

[0062] The two screws 74 are an example of conveying members rotatably provided in the flow path section 52. The two screws 74 are arranged to mesh with each other and convey the residue R toward the downstream side in the conveying direction by rotation. The upstream side portions of the two screws 74 face the buffer chamber 26 in the up-down direction.

[0063] The reverse screw 75 is provided on the downstream side of the two screws 74 in the conveying direction and at a position upstream of the driving section 76. It should be noted that the reverse screw 75 is formed with a blade portion having a direction opposite to that of the blade portion of the screw 74. A configuration in which the blade portion of the screw 74 and the blade portion of the reverse screw 75 are integrally formed on one screw may also be used.

[0064] The upstream end portion of the reverse screw 75 is located at a position facing the residue discharge port 63 in the Z direction. The reverse screw 75 is rotated by the driving section 76, thereby conveying the residue R toward the residue discharge port 63. In other words, the reverse screw 75 blocks the residue R flowing in the conveying direction between the two screws 74 and the driving section 76, thereby effectively causing the residue R to fall toward the residue discharge port 63.

[0065] The drive unit 76 is located on the downstream side compared to the flow path unit 52, the screw 74, and the reverse screw 75. In addition, the drive unit 76 is located on the downstream side of a water-cooling pipe 88 described later. The drive unit 76 can rotate the two screws 74 and the reverse screw 75. Specifically, the drive unit 76 includes a motor 77 connected to the two screws 74 and a motor controller 78 that controls the rotation of the motor 77.

[0066] The motor controller 78 can switch the forward rotation and reverse rotation of the motor 77. In the present embodiment, the forward rotation of the motor 77 means the rotation of the motor 77 when the two screws 74 convey the residue R toward the downstream side in the conveying direction and the reverse screw 75 conveys the residue R toward the upstream side in the conveying direction. The reverse rotation of the motor 77 means the rotation of the motor 77 when the two screws 74 convey the residue R toward the upstream side in the conveying direction. It should be noted that when the motor 77 rotates in the reverse direction, the transmission of the driving force from the motor 77 to the reverse screw 75 may also be blocked.

[0067] (Temperature adjustment unit)

[0068] The temperature adjustment unit 82 can change the temperature of the residue R conveyed by the conveying unit 72. The operation of the temperature adjustment unit 82 is controlled by the recycling machine control unit 98. Specifically, the temperature adjustment unit 82 includes a heating unit 84 and a cooling unit 87. The heating unit 84 is provided in the heating jacket 54. The cooling unit 87 is provided in the cooling jacket 58. That is, the heating unit 84 is located on the upstream side in the conveying direction compared to the cooling unit 87.

[0069] The heating unit 84 includes a heater 85 and a power supply unit 86. The power supply unit 86 supplies power to the heater 85. The heater 85 is provided inside the wall portion 55. The heater 85 is an example of a heating portion. The heater 85 has a heating element that is bent and folded corresponding to the shape of the wall portion 55.

[0070] When the heater 85 is supplied with power from the power supply unit 86, it generates heat to heat the residue R via the wall portion 55. That is, the heating unit 84 heats the residue R. It should be noted that the calorific value of the heater 85 is controlled by the recycling machine control unit 98 so that the temperature of the residue R heated by the heater 85 becomes a temperature within a set range.

[0071] The cooling unit 87 includes a water-cooling pipe 88 and a supply pump 89. The supply pump 89 supplies water to the inside of the water-cooling pipe 88. The water-cooling pipe 88 is provided inside the wall portion 59. The water-cooling pipe 88 is an example of a cooling portion. The water-cooling pipe 88 is a pipe that is bent and folded corresponding to the shape of the wall portion 59. When the supply pump 89 operates, water flows inside the water-cooling pipe 88.

[0072] The water inside the water-cooling pipe 88 cools the wall portion 59, thereby cooling the residue R. That is, the cooling unit 87 cools the residue R. It should be noted that a part of the water-cooling pipe 88 is arranged in the vertical direction with the discharge flow path 65( Figure 4 ). In other words, the water-cooling pipe 88 is arranged in the flow path portion 52 so that the residue R discharged from the flow path portion 52 toward the residue box 102 can be cooled by the water flowing inside the water-cooling pipe 88.

[0073] When the buffer chamber 26 is projected onto the flow path portion 52 in the vertical direction, the overlapping area of the flow path portion 52 and the buffer chamber 26 is set as the imaginary area K. Figure 2 The range of the imaginary area K in the conveying direction is shown by an arrow K in the figure. At least a part of the heater 85 is located inside the imaginary area K. The water-cooling pipe 88 is located outside the imaginary area K.

[0074] A nozzle 91 is provided on a part of the wall portion 59 in the section where the cooling unit 87 is provided. As an example, the nozzle 91 injects nitrogen supplied from the nitrogen supply unit 46 into the downstream flow path 62. In the downstream flow path 62, the flow of the combustible gas toward the residue box 102 is suppressed by injecting nitrogen from the nozzle 91.

[0075] (Upstream discharge portion)

[0076] As Figure 3 shown, the upstream discharge portion 92 is provided at the upstream end of the flow path portion 52. The upstream discharge portion 92 can discharge a part of the residue R( Figure 2 ) and the waste object W from the flow path portion 52. The waste object W is a substance discharged into the buffer chamber 26 in a state where thermal decomposition is insufficient, and refers to a substance other than the object to be reused. It should be noted that it is preferable that the upstream discharge portion 92 only discharges the waste object W, but it is difficult to separate the waste object W from the residue R. Therefore, as described above, the upstream discharge portion 92 can also discharge a part of the residue R.

[0077] As an example, the upstream discharge portion 92 includes a discharge die 94 and a gate valve 96. A heater 85 is provided on a part of the discharge die 94. The discharge die 94 has an upstream discharge flow path 95 through which the waste object W and the residue R( Figure 2 ) flow. The flow cross-sectional area of the upstream discharge flow path 95 decreases from the downstream side to the upstream side in the conveying direction. When the screw 74 rotates in the reverse direction, the waste object W and the residue R inside the upstream discharge portion 92 are extruded outward from the upstream discharge portion 92 and discharged.

[0078] The gate valve 96 is movably provided on the discharge die 94. The gate valve 96 can move upward and downward in the vertical direction. The operation of the gate valve 96 can be performed by the operator H( Figure 2Any of the manual operations or automatic operations using a motor or the like. When the motor 77 ( Figure 2 ) rotates forward, the upstream discharge flow path 95 is closed by moving downward through the gate valve 96. When the motor 77 rotates in reverse, the upstream discharge flow path 95 is opened by moving upward through the gate valve 96.

[0079] (Recycling machine control unit)

[0080] As Figure 2 shown, as an example, the recycling machine control unit 98 controls the rotation of the motor 77 with the help of the motor controller 78. The rotation control of the motor 77 includes controls for rotation start, rotation stop, rotation speed, and rotation direction (forward rotation, reverse rotation). It should be noted that the recycling machine control unit 98 includes a CPU, a memory, and a storage. The rotation of the motor 77 is controlled by the CPU executing the program stored in the memory.

[0081] <Residue box>

[0082] The residue box 102 is an example of a recycling unit that recycles the residue R discharged from the flow path unit 52. The residue box 102 is detachably installed on the attachment / detachment unit 66 of the flow path unit 52.

[0083] As Figure 4 shown, as an example, the residue box 102 includes a bottom wall 104, a plurality of casters 105, side walls 106, an upper wall 109, an inflow portion 112, a flange 114, and a lid member 116.

[0084] The bottom wall 104 is formed in a flat plate shape along the left - right direction and the conveying direction. The plurality of casters 105 are rotatably mounted on the bottom wall 104. The side walls 106 stand upright from the bottom wall 104 to the upper side in the up - down direction. When viewed from the up - down direction, the side walls 106 are formed in a cylindrical shape. The shape of the side walls 106 can be either a cylindrical shape or a square - cylindrical shape. The upper wall 109 covers the space surrounded by the side walls 106. The space surrounded by the bottom wall 104, the side walls 106, and the upper wall 109 is set as the storage space 111. The residue R is stored in the storage space 111.

[0085] A through - hole 107 penetrating the side wall 106 is formed at a position above the center in the up - down direction of the side wall 106 and is a part of the circumferential direction of the side wall 106. A transparent member 108 is inserted into the through - hole 107. As an example, the transparent member 108 uses glass. In addition, an upper limit line UL extending in the horizontal direction (as an example, the left - right direction) is displayed on the transparent member 108.

[0086] Operator H visually observes the interior of the residue box 102 through the transparent member 108. When at least a part of the residue R is located at a position above the upper limit line UL, Operator H determines that the residue box 102 is in a full state. When the entire residue R is located at a position below the upper limit line UL, Operator H determines that the residue box 102 is in a state where it can store residues.

[0087] The inflow portion 112 is formed in a cylindrical shape having a central axis along the vertical direction. The shape of the inflow portion 112 can be either a cylindrical shape or a rectangular cylindrical shape. Further, the inflow portion 112 extends upward in the vertical direction from the central portion in the left-right direction and the conveying direction of the upper wall 109. The space 112A inside the inflow portion 112 is connected to the storage space 111. The flange 114 projects outward from the upper end portion in the vertical direction of the inflow portion 112. The flange 114 has a shape and size that can contact the contact portion 68.

[0088] The lid member 116 is provided at the upper end portion in the vertical direction of the inflow portion 112. As an example, the lid member 116 is provided so as to be slidable in the left-right direction. By moving the lid member 116 in the left-right direction, the inflow portion 112 is opened or closed. When the lid member 116 is disposed at the closed position, the inflow of the residue R into the residue box 102 is restricted. When the lid member 116 is disposed at the open position, the residue R can flow into the residue box 102. In the present embodiment, as an example, Operator H moves the lid member 116.

[0089] <Function of the First Embodiment>

[0090] Refer to Figures 1 to 4 Describe the function of the thermal decomposition system 10 of the first embodiment.

[0091] During the start-up operation of each part of the thermal decomposition system 10, it is possible that the waste object W is generated due to insufficient thermal decomposition in the extruder 12. Therefore, with the gate valve 96 moved to the upper open state, the screw 74 rotates in the reverse direction. As a result, the waste object W discharged from the extruder 12 to the buffer chamber 26 is discharged outward from the upstream discharge flow path 95, so that the waste object W is difficult to be recovered into the residue box 102.

[0092] During the operation of the thermal decomposition system 10, with the gate valve 96 moved to the lower closed state, the screw 74 rotates forward. The waste plastic P introduced into the hopper 13 is thermally decomposed inside the cylinder 14 and then discharged from the cylinder 14 as a mixture M. The mixture M discharged from the cylinder 14 flows into the interior of the buffer chamber 26 through the discharge pipe 24.

[0093] The gas G in the mixture M passes through the pipe 36 in a negative pressure state and is sent to the heat exchanger 44 via the drain tank 42. Then, the gas G condenses by cooling in the heat exchanger 44, and thus is recovered as the liquid substance N.

[0094] On the other hand, the residue R (solid S or liquid Q) in the mixture M is conveyed to the downstream side in the conveying direction along with the rotation of the screw 74. At this time, since the residue R is heated in the heating jacket 54, adhesion of the residue R to the buffer chamber 26 and the cylinder 14 caused by solidification of the liquid Q or the like can be suppressed. That is, the conveying state of the residue R is stable.

[0095] In the cooling jacket 58, the liquid Q gradually solidifies. As a result, most of the residue R conveyed to the position facing the discharge pipe 64 in the flow path portion 52 is discharged in the form of the solid S, and falls into the inside of the residue box 102 through the discharge pipe 64.

[0096] The temperature of the residue R recovered in the residue box 102 is lower than the temperature at the time of being discharged into the buffer chamber 26. Therefore, even if the residue box 102 becomes full due to the residue R, the temperature of the discharge pipe 64 and the residue box 102 can be suppressed from becoming high, so that it is easy to move the sliding gate 69 to the closed position and it is easy to replace the residue box 102.

[0097] The residue R discharged into the buffer chamber 26 is conveyed by the conveying portion 72. Therefore, the residue R hardly accumulates inside the buffer chamber 26, and thus the operation of the extruder 12 can be continued.

[0098] As described above, in the thermal decomposition system 10, the conveying portion 72 moves the residue R discharged from the extruder 12 from the buffer chamber 26 toward the residue box 102. In addition, the flow path portion 52 can function as a buffer portion for temporarily accumulating the residue R. In other words, the recovery machine 50 functions as a buffer portion for temporarily accumulating the residue R. Thereby, it is possible to prevent the buffer chamber 26 from being filled with the residue R and gain time for replacing the residue box 102, and thus the residue box 102 can be replaced efficiently. As an example of efficiently replacing the residue box 102, the residue box 102 can be replaced while the extruder 12 continues to operate.

[0099] According to the thermal decomposition system 10, since the gas G generated by thermal decomposition is discharged through the pipe 36 from the gas discharge port 34A, the gas G hardly accumulates inside the buffer chamber 26. Therefore, it is possible to prevent the pressure inside the buffer chamber 26 from becoming high.

[0100] In the thermal decomposition system 10, the temperature adjustment portion 82 can adjust the temperature of the conveyed residue R. Therefore, compared with a configuration in which the temperature of the residue R is not adjusted, the temperature change of the residue R during conveyance is suppressed, and thus the conveying state of the residue R by the conveying portion 72 can be stabilized.

[0101] According to the thermal decomposition system 10, the temperature adjustment unit 82 reduces the temperature of the residue R being transported by having the water-cooled pipe 88, so that the temperature rise of the residue box 102 that has recovered the residue R can be suppressed. In addition, since the water-cooled pipe 88 is provided inside the wall portion 59, the cooling efficiency can be improved as compared with a configuration in which the residue R is cooled from the outside of the wall portion 59.

[0102] In the thermal decomposition system 10, the heater 85 is located upstream of the water-cooled pipe 88. The calorific value of the heater 85 is controlled by the recovery machine control unit 98 so that the temperature of the residue R heated by the heater 85 becomes a temperature within a set range. Therefore, a sharp drop in the temperature of the residue R can be suppressed and the fluidity of the residue R can be ensured. As a result, since the transfer unit 72 can easily transfer the residue R, the residue R can be prevented from remaining inside the flow path unit 52.

[0103] In addition, at least a part of the heater 85 is located inside the imaginary region K, and the water-cooled pipe 88 is located outside the imaginary region K, so that the buffer chamber 26 is not easily cooled. As a result, a part of the residue R can be prevented from adhering to the inner surface of the buffer chamber 26.

[0104] The upstream side portion of the flow path unit 52 is adjacent to the buffer chamber 26. And the high-temperature residue R after thermal decomposition flows into the upstream side portion of the flow path unit 52. As a result, the temperature of the upstream side portion of the flow path unit 52 is higher than that of the downstream side portion. Here, in the thermal decomposition system 10, the drive unit 76 is located on the downstream side of the flow path unit 52. As a result, compared with a configuration in which the drive unit 76 is located on the upstream side of the flow path unit 52, the drive unit 76 can be prevented from being heated. In addition, since the drive unit 76 is located downstream of the cooling unit 87 (water-cooled pipe 88), it is not easily heated.

[0105] In the thermal decomposition system 10, an upstream discharge unit 92 is provided at the upstream end of the flow path unit 52. When the motor 77 rotates in the reverse direction, the residue R is discharged from the upstream discharge unit 92. As a result, even when the waste object W is generated at the start of the extruder 12 or the like, the waste object W is discharged from the upstream discharge unit 92, so that the waste object W can be prevented from being recovered into the residue box 102.

[0106] In the thermal decomposition system 10, the upstream discharge unit 92 includes a gate valve 96. And the gate valve 96 closes the upstream discharge flow path 95 when the motor 77 rotates forward, and opens the upstream discharge flow path 95 when the motor 77 rotates in the reverse direction. As a result, not only can the waste object W be discharged, but also external gas can be prevented from flowing into the flow path unit 52 from the upstream discharge flow path 95 during the transfer of the residue R.

[0107] 〔Second Embodiment〕

[0108] Based on the drawings, the thermal decomposition system 120 of the second embodiment of the present disclosure will be described. It should be noted that the components that are the same as or equivalent to those of the first embodiment are denoted by the same reference numerals and the description thereof is omitted.

[0109] Figure 5 A part of the thermal decomposition system 120 of the second embodiment is shown. The thermal decomposition system 120 and the thermal decomposition system 10 ( Figure 1 ) have different configurations after the discharge pipe 64. Therefore, the configuration after the discharge pipe 64 will be described.

[0110] A discharge pipe 64, a downstream discharge pipe 122, a downstream discharge pipe 124, and a switching valve 126 are provided on the flow path portion 52. In addition, as an example, residue boxes 102A, 102B, and 102C are used in the thermal decomposition system 120. It should be noted that the residue boxes 102A, 102B, and 102C respectively have the same configuration as the residue box 102 ( Figure 4 ).

[0111] The downstream discharge pipe 122 and the downstream discharge pipe 124 are examples of a plurality of downstream discharge portions. The downstream discharge pipe 122 and the downstream discharge pipe 124 are respectively connected to the lower end portions in the vertical direction of the discharge pipe 64. The downstream discharge pipe 122 is an example of one downstream discharge portion and an example of other downstream discharge portions. The downstream discharge pipe 124 is an example of other downstream discharge portions and an example of one downstream discharge portion.

[0112] The downstream discharge pipe 122 has an inclined portion 122A and a vertical portion 122B. The inclined portion 122A extends obliquely downward from the discharge pipe 64 toward the upstream side in the conveying direction. The vertical portion 122B extends downward in the vertical direction from the lower end portion of the inclined portion 122A. A mounting / dismounting portion 66 is provided at the lower end portion of the vertical portion 122B. The residue box 102A is installed on the downstream discharge pipe 122.

[0113] The downstream discharge pipe 124 has an inclined portion 124A and a vertical portion 124B. The inclined portion 124A extends obliquely downward from the discharge pipe 64 toward the downstream side in the conveying direction. The vertical portion 124B extends downward in the vertical direction from the lower end portion of the inclined portion 124A. A mounting / dismounting portion 66 is provided at the lower end portion of the vertical portion 124B. The residue box 102B is installed on the downstream discharge pipe 124.

[0114] The switching valve 126 is provided at the portion (branch portion) where the downstream discharge pipe 122 and the downstream discharge pipe 124 are connected to the discharge pipe 64. The switching valve 126 is an example of a switching portion. Specifically, the switching valve 126 is operated (rotated) by the operator H, whereby the flow path for discharging the residue R from the discharge pipe 64 can be switched from the downstream discharge pipe 122 to the downstream discharge pipe 124 or from the downstream discharge pipe 124 to the downstream discharge pipe 122.

[0115] <Function of the Second Embodiment>

[0116] Refer to Figure 5 Explain the function of the thermal decomposition system 120 of the second embodiment.

[0117] When the switching valve 126 is operated to one side in the rotational direction, the inside of the downstream discharge pipe 122 is connected to the inside of the discharge pipe 64, and the downstream discharge pipe 124 is closed. When the thermal decomposition system 120 is operating, the residue R discharged from the flow path unit 52 to the discharge pipe 64 flows in the downstream discharge pipe 122 and is recovered in the residue box 102A. Here, when the operator H visually confirms and determines that the residue box 102A is full, the operator H operates the switching valve 126 to the other side in the rotational direction. As a result, the inside of the downstream discharge pipe 124 is connected to the inside of the discharge pipe 64, and the downstream discharge pipe 122 is closed. Then, the residue R is recovered in the residue box 102B.

[0118] During the period when the residue R is being recovered into the residue box 102B, the operator H detaches the residue box 102A from the attachment / detachment unit 66. Then, the operator H installs the empty residue box 102C on the attachment / detachment unit 66 of the downstream discharge pipe 122. When the residue box 102B becomes full due to the residue R, the residue box 102B is replaced with the residue box 102C by the same procedure.

[0119] As described above, in the thermal decomposition system 120, by operating the switching valve 126, the flow path for discharging the residue R is switched from the downstream discharge pipe 122 to the downstream discharge pipe 124, or from the downstream discharge pipe 124 to the downstream discharge pipe 122. Thus, when the residue R is flowing in one of the downstream discharge pipe 122 and the downstream discharge pipe 124, the residue R does not flow into the other, so that even when the residue R is continuously discharged from the discharge pipe 64, the time for replacing the residue box 102 can be ensured.

[0120] 〔Third Embodiment〕

[0121] Based on the drawings, explain the thermal decomposition system 130 of the third embodiment of the present disclosure. It should be noted that the same reference numerals are assigned to the components that are the same as or equivalent to those of the first embodiment, and the description thereof is omitted.

[0122] Figure 6 A part of the thermal decomposition system 130 of the third embodiment is shown. The thermal decomposition system 130 is different from the thermal decomposition system 10 ( Figure 1 ) in that it includes a control unit 132 and a residue box 136.

[0123] The control unit 132 includes the functions of the extruder control unit 22 ( Figure 1 ) and the recovery machine control unit 98 ( Figure 1)'s function. Therefore, the extruder control unit 22 and the recycling machine control unit 98 are not provided in the thermal decomposition system 130. The control unit 132 has a main body unit 133 and a display unit 134.

[0124] The main body unit 133 includes a CPU, a memory, and a storage. The operations of the extruder 12 and the recycling machine 50 are controlled by the CPU executing the programs stored in the memory. The detection information from the detection sensor 138 described later is input to the main body unit 133.

[0125] As an example, the display unit 134 is a touch panel. Therefore, on the display unit 134, not only can information related to the extruder 12 and the recycling machine 50 be displayed, but also the operations (input of information) of the extruder 12 and the recycling machine 50 can be performed.

[0126] In the residue box 136, the transparent member 108 ( Figure 4 ) of the residue box 102 ( Figure 4 ) is replaced with the detection sensor 138. The detection sensor 138 is an optical sensor. As an example, the detection sensor 138 detects whether the top of the residue R accumulated inside the residue box 136 reaches a preset full position. And when the position of the top of the residue R reaches the full position, the detection sensor 138 outputs a signal as full information to the main body unit 133.

[0127] <Function of the Third Embodiment>

[0128] Refer to Figure 6 to explain the function of the thermal decomposition system 130 of the third embodiment.

[0129] When the main body unit 133 receives the signal of full information from the detection sensor 138, it notifies the full state of the residue box 136 by performing a full warning display on the display unit 134. When the operator H sees the warning display, the operator H closes the discharge pipe 64 by moving the sliding gate 69. Then, the operator H detaches the residue box 136 from the attachment / detachment unit 66.

[0130] In addition, after the operator H installs another empty residue box 136 on the attachment / detachment unit 66, the operator H opens the discharge pipe 64 by moving the sliding gate 69. Thus, the residue R is recovered using another residue box 136. The warning display on the display unit 134 is cancelled by the operator H operating the display unit 134. In this way, according to the thermal decomposition system 130, even if the operator H does not visually observe the inside of the residue box 136, the operator H can know the full state of the residue box 136.

[0131] It should be noted that when the main body 133 receives a signal indicating that the information is full, it can also control the reduction of the discharge amount of the residue R (mixture M) from the extruder 12 to the buffer chamber 26 by controlling the rotation speed of the screw 16 to decrease or the like. Thus, the residue box 136 can be replaced efficiently. As an example of efficiently replacing the residue box 136, the residue box 136 can be replaced while the extruder 12 continues to operate.

[0132] 〔Modification Example〕

[0133] The following describes a modification example different from the first, second, and third embodiments of the present disclosure. It should be noted that the same reference numerals are assigned to the components that are the same as or equivalent to those of the first, second, and third embodiments, and repeated descriptions are omitted.

[0134] As a modification example of the thermal decomposition system 10, Figure 7 A configuration in which a part of the transfer pipe 142 is connected to the discharge die 94 is shown. The transfer pipe 142 is bent downward in the vertical direction. A heater 143 is buried in the transfer pipe 142. The heater 143 heats the object to be discarded W to a temperature for heat preservation. A detachable part 66 is provided at the lower end of the transfer pipe 142 in the vertical direction.

[0135] An upstream side box 144 is installed at the detachable part 66. The upstream side box 144 is the same as the residue box 102 ( Figure 3 ). However, the object to be discarded W is recovered inside the upstream side box 144. In this way, the object to be discarded W can be recovered using the upstream side box 144 instead of being discharged to the outside of the recovery machine 50.

[0136] The resin material used in the thermal decomposition systems 10, 120, and 130 is not limited to the waste plastic P, and other resin materials can also be used. The residue R is not limited to the solid S or the liquid Q, and can also be the solid S and the liquid Q.

[0137] The thermal decomposition device is not limited to a structure that extrudes the thermally decomposed material to the outside of the device like the extruder 12, and can also be a structure that shoots the thermally decomposed material to the outside of the device or a structure that allows the material to flow out to the outside of the device.

[0138] In the buffer chamber 26, it is sufficient that the residue R can flow out from the buffer chamber 26 to the heating jacket 54. Therefore, it is not necessary for the entire lower end of the cylindrical part 27 to be open downward. For example, a bottom wall formed with a through hole can be provided at the lower end of the cylindrical part 27, and the residue R can flow out through the through hole. In addition, it is preferable that the buffer chamber 26 has a temperature adjustment part. The temperature adjustment part heats or cools the buffer chamber 26 as needed, thereby adjusting the temperature inside the buffer chamber 26 to the target temperature.

[0139] The screws 16 and 74 are not limited to a twin-shaft structure, and may also be a single-shaft structure or a multi-shaft structure with three or more shafts.

[0140] A downstream discharge pipe 122, a downstream discharge pipe 124, a switching valve 126, a residue box 136, and a motor may also be provided in the thermal decomposition system 130. The switching valve 126 rotates by the motor. Here, the signal of the full information of the detection sensor 138 may also be used as a trigger signal for starting the drive of the motor to automatically perform the rotation (switching operation) of the switching valve 126.

[0141] The thermal decomposition systems 10, 120, and 130 may also not have a gas discharge port 34A. For example, when the buffer chamber 26 is a large container extending in the vertical direction, the upper part of the buffer chamber 26 becomes a storage part for storing the gas G. In this configuration, since it is not necessary to frequently discharge the gas G, the gas discharge port 34A may also be absent. It should be noted that when the gas G is recovered and used, the gas G needs to be discharged from the buffer chamber 26. When the pressure inside the buffer chamber 26 becomes high, the gate valve 96 may also be operated to discharge the gas G.

[0142] The thermal decomposition systems 10, 120, and 130 may also not have a temperature adjustment unit 82, a heater 85, and a water-cooling pipe 88. For example, when the flow path part 52 is long in the transport direction, the temperature of the residue R transported by the transport part 72 gradually decreases as it approaches the downstream side. Therefore, recovery by the residue box 102 can be achieved.

[0143] The heater 85 may also be arranged outside the wall part 55. In addition, the heater 85 is not limited to a position upstream of the water-cooling pipe 88. For example, the heater 85 may also be provided at a position downstream of the water-cooling pipe 88 in the transport direction, and the residue R can be easily transported by heating with the heater 85. The water-cooling pipe 88 may also be arranged outside the wall part 59. The whole of the heater 85 may also be located inside the imaginary area K. In addition, a part of the water-cooling pipe 88 may also be located inside the imaginary area K.

[0144] The cooling part is not limited to the water-cooling pipe 88. The cooling part may, for example, also include a structure using a Peltier element for cooling or a structure for cooling by blowing air with a fan.

[0145] The drive part 76 may also be located upstream of the water-cooling pipe 88. Specifically, the drive part 76 may also be located upstream of the flow path part 52 in the transport direction.

[0146] When the waste object W can be recovered by the residue box 102, the upstream discharge part 92 may also be absent.

[0147] Explanation of reference numerals

[0148] 2: Ground, 10: Thermal decomposition system, 12: Extruder, 13: Hopper, 14: Cylinder, 15: Heater, 16: Screw, 18: Driving mechanism, 22: Extruder control unit, 24: Discharge pipe, 24A: Horizontal part, 24B: Vertical part, 26: Buffer chamber, 27: Cylinder, 28: Side wall, 28A: Through hole, 29: Side wall, 32: Sealing part, 34: Cover, 34A: Gas discharge port, 36: Pipe, 42: Drain tank, 44: Heat exchanger, 46: Nitrogen supply unit, 48: Nozzle, 50: Recovery machine, 52: Flow path, 53: Inlet, 54: Heating sleeve, 55: wall, 56: flange, 57: upstream flow path, 58: cooling jacket, 59: wall, 61: flange, 62: downstream flow path, 63: residue discharge port, 64: discharge pipe, 64A: outer peripheral surface, 64B: slit, 65: discharge flow path, 66: mounting and disassembling portion, 68: contact portion, 68A: horizontal wall, 68B: vertical wall, 69: sliding gate, 71: heat insulation member, 72: conveying portion, 74: screw, 75: reverse screw, 76: driving portion, 77: motor, 78: motor controller, 82: temperature adjustment portion, 84: heating unit, 85: heater, 86: power supply portion , 87: cooling unit, 88: water cooling pipe, 89: supply pump, 91: nozzle, 92: upstream discharge part, 94: discharge mold, 95: upstream discharge flow path, 96: gate valve, 98: recovery machine control part, 102: residue box, 102A: residue box, 102B: residue box, 102C: residue box, 104: bottom wall, 105: caster, 106: side wall, 107: through hole, 108: transparent part, 109: upper wall, 111: storage space, 112: inflow part, 112A: space, 114: flange, 116: cover part, 120: thermal decomposition system, 122: Downstream discharge pipe, 122A: inclined portion, 122B: vertical portion, 124: downstream discharge pipe, 124A: inclined portion, 124B: vertical portion, 126: switching valve, 130: thermal decomposition system, 132: control unit, 133: main body, 134: display unit, 136: residue box, 138: detection sensor, 142: delivery piping, 143: heater, 144: upstream side box, G: gas, H: operator, K: virtual area, M: mixture, N: liquid substance, P: waste plastic, Q: liquid, R: residue, S: solid, UL: upper limit line, W: waste object.

Claims

1. A thermal decomposition system, wherein, Comprising: A thermal decomposition device for thermally decomposing a resin material; A housing part for housing the residue discharged from the thermal decomposition device that has thermally decomposed the resin material; A flow path part for receiving the residue from the housing part; A recovery part that is detachably provided to the flow path part to recover the residue discharged from the flow path part; And A conveying part for conveying the residue received from the housing part toward the recovery part.

2. The thermal decomposition system according to claim 1, wherein, The housing part has a gas discharge port, The gas generated by the thermal decomposition of the resin material is discharged from the gas discharge port.

3. The thermal decomposition system according to claim 2, wherein, It further includes a temperature adjustment part that can adjust the temperature of the residue conveyed by the conveying part.

4. The thermal decomposition system according to claim 3, wherein, The temperature adjustment part has a cooling part provided in the flow path part for cooling the residue.

5. The thermal decomposition system according to claim 4, wherein, The flow path part has a cylindrical wall part, The cooling part is provided inside the wall part.

6. The thermal decomposition system according to claim 4, wherein, The temperature adjustment part has a heating part provided in the flow path part for heating the residue, The heating part is located upstream of the cooling part in the conveying direction of the residue.

7. The thermal decomposition system according to claim 6, wherein, When the housing part is projected onto the flow path part, the overlapping area of the flow path part and the housing part is set as an imaginary area, At least a part of the heating part is located inside the imaginary area, The cooling part is located outside the imaginary area.

8. The thermal decomposition system according to any one of claims 4 to 7, wherein, The conveying part includes: A conveying member rotatably provided in the flow path part for conveying the residue; and A driving part located downstream of the cooling part in the conveying direction of the residue for rotating the conveying member.

9. The thermal decomposition system according to claim 8, wherein, The driving part has a motor capable of switching between forward rotation and reverse rotation, The conveying member conveys the residue downstream in the conveying direction during the forward rotation of the motor, and conveys the residue upstream in the conveying direction during the reverse rotation of the motor, An upstream discharge part capable of discharging the residue from the flow path part is provided at the upstream end of the flow path part in the conveying direction.

10. The thermal decomposition system according to claim 9, wherein, The upstream discharge part includes: A discharge die having an upstream discharge flow path for the residue to flow through; and A gate valve capable of opening and closing the upstream discharge flow path, During the forward rotation of the motor, the upstream discharge flow path is closed by the gate valve, and during the reverse rotation of the motor, the upstream discharge flow path is opened.

11. According to the thermal decomposition system described in claim 1, wherein, In the flow path part, there are provided: A plurality of downstream discharge parts for detachably mounting the recovery part; and A switching part capable of switching the flow path for discharging the residue from one downstream discharge part to another downstream discharge part.

12. A thermal decomposition system for waste plastics, wherein, Comprising: A first extruder capable of thermally decomposing waste plastics; A second extruder into which the thermally decomposed residue discharged from the first extruder is fed; And A recovery part that can be attached and detached relative to the second extruder for recovering the residue.

13. According to the thermal decomposition system for waste plastics described in claim 12, wherein, The first extruder has a gas discharge port, The gas generated by the thermal decomposition of the waste plastics is discharged from the gas discharge port.

14. According to the thermal decomposition system for waste plastics described in claim 13, wherein, The residue is solid or liquid.

Images