DISPOSAL PLANT FOR OLD TIRES

Description

[0001] The present invention relates to a waste tire disposal plant, in particular by means of pyrolysis. This type of plant is used in the context of waste disposal in the industrial field.

[0002] A waste tire recycling and / or disposal plant is known in the state of the art, for example of the type described in patent application IT 102011901968216. Such a plant comprises a furnace into which the entire tires to be subjected to pyrolysis are placed. The furnace is surrounded by gas burners which provide the necessary heat for the pyrolysis reaction.

[0003] The plant further comprises a heat exchanger which causes the liquid phase condensation of gas oil and its separation from the gaseous phase of the pyrolysis vapours, containing synthesis gas. Part of the gas oil produced is used for the operation of at least one generator set of the plant for the production of electricity. Part of the synthesis gas produced is used for heating the furnace.

[0004] The remaining vapours are lastly sent to a fume suppressor from which the emission of water vapor is obtained. The solid residues of the pyrolysis process, comprising carbon black and steel powder, are collected directly from the pyrolytic furnace. In particular, carbon black and steel are collected from a conveyor belt outside the furnace and lastly separated by electromagnets which extract the steel.

[0005] A similar plant is also known from document DE 2143452 for the recovery of reusable raw materials, auxiliary materials and waste materials by means of thermochemical decomposition of such materials or raw materials. Such a plant comprises a gas-tight reaction chamber rotated by drive means and means for the elimination of at least part of the gases coming from the chamber.

[0006] Furthermore, from WO 2019 / 113626 it is known to use inert gases in a waste tire disposal plant to obtain an anaerobic environment during a pyrolytic process.SUMMARY OF THE INVENTION

[0007] Disadvantageously, in the above-described known furnace, the pyrolysis reaction is completed over a long time, resulting in considerable energy consumption.

[0008] Furthermore, the solid pyrolysis products must be collected and separated outside the pyrolytic furnace, increasing the complexity of the plant itself.

[0009] In this context, the technical task underlying the present invention is to propose a waste tire disposal plant which overcomes the drawbacks of the prior art mentioned above.

[0010] In particular, it is an object of the present invention to provide a waste tire disposal plant which ensures that the completion of a pyrolysis reaction under anaerobic conditions is easily obtained.

[0011] A further object of the present invention is to provide a waste tire disposal plant which allows to complete the pyrolysis reaction with the same number of tires for disposal in less time.

[0012] It is a further object of the present invention to provide a waste tire disposal plant which facilitates the collection of the solid pyrolysis products.

[0013] The mentioned technical task and the specified objects are substantially achieved by a waste tire disposal plant comprising the technical specifications set out in one or more of the appended claims.

[0014] The invention solves the proposed technical problem. In particular, the use of a treatment chamber, comprising a drum associated with drive means, allows the tires to be stirred during the pyrolysis process. This allows to add a mechanical action to the thermal action, obtaining the degradation of the tires in less time with respect to that achievable by the thermal action alone.

[0015] Furthermore, by virtue of a complete rotation of the drum it is possible to efficiently separate the solid pyrolysis products, such as carbon black and steel, without the use of conveyor belts and electromagnets, thus reducing the complexity of the plant. In particular, the drum has apertures which filter the solid residues, retaining the steel inside the drum and depositing the black powder by gravity to a screw placed within the treatment chamber.

[0016] Finally, the presence of an inert gas seal allows to avoid the escape of the vapours produced by the pyrolysis and the entry of oxygen from outside the treatment chamber.LIST OF FIGURES

[0017] Further features and advantages of the present invention will become more apparent from the description of an indicative, and therefore non-limiting description of a preferred but not exclusive embodiment of a waste tire disposal plant, as illustrated in the appended drawings, wherein: Figure 1 is a perspective view of a waste tire disposal plant according to the present invention; Figure 2 shows a side view of a first detail of the plant of Figure 1; Figure 3 shows a rear view of the detail of Figure 2; Figure 4 shows a front perspective view of the plant of Figure 1, some parts of which have been removed to better illustrate others; Figure 5 shows a sectional side view of the detail of Figure 2; Figure 6 shows an enlarged view of a detail of figure 5; Figure 7 shows a perspective view of a second detail of the plant of Figure 1; Figure 8 shows a side view of a third detail of the plant of Figure 1; Figure 9 shows a perspective view of the detail of Figure 8; Figure 10 shows a perspective view of a fourth detail of the plant of Figure 1. DETAILED DESCRIPTION

[0018] With reference to the appended drawings, the number 1 generally indicates a waste tire disposal plant in accordance with the present invention.

[0019] The disposal of tires (not shown in the appended drawings) occurs in particular by means of a pyrolysis reaction which is carried out by providing heat, in the absence of oxygen, to the tires for disposal, obtaining gaseous, liquid and solid products.

[0020] The plant 1 comprises a treatment chamber 2. Such a chamber 2 has the function of receiving the tires for disposal. The plant 1 further comprises four legs 22 connected to the chamber 2, which have the function of supporting it.

[0021] With particular reference to figure 5, the chamber 2 has a substantially cylindrical shape. In particular, the chamber 2 comprises an upper portion 28 and a lower portion 29. The chamber 2 further comprises an outer wall 21. The outer wall 21 comprises an opposite front portion 211 and a rear portion 212.

[0022] It should be noted that the chamber 2 further comprises an insulating layer 26 inserted in the outer wall 21. Such an insulating layer 26 advantageously improves the energy efficiency of the plant 1.

[0023] The chamber 2 further comprises a door 25, placed in particular on the front portion 211 of the outer wall 21, to allow the insertion of the tires inside the chamber 2.

[0024] The plant 1 further comprises a drum 8 located in particular within the chamber 2. The drum 8 is rotatable about a rotation axis R. The drum 8 has a compartment 82 for holding the tires for disposal. The compartment 82 is accessible by means of the door 25 described above.

[0025] More in detail, the compartment 82 has an inner surface 83 from which at least one, preferably three, projections 84 extend. The projection 84 preferably has the shape of a blade and is advantageously capable of contributing to the degradation of the tires by means of a mechanical action, as will be better explained in the following.

[0026] In further detail, the drum 8 has a plurality of apertures 81 located at regular intervals and configured to filter the solid residues. The apertures 81 also convey the pyrolysis vapours outside the drum 8. In particular, there is a net (not illustrated in the appended drawings) at the apertures 81. Such a net is preferably metallic. The net has meshes, in particular with an area between 0.5 cm 2< and 1.5 cm 2< , preferably equal to 1 cm 2< .

[0027] To implement the pyrolysis process, the plant 1 is provided with heating means 9, which are located inside the chamber 2, in particular outside the drum 8. In the embodiment described, the heating means 9 comprise three pairs of resistors (not illustrated in the appended drawings). Such heating means 9 radiate heat to the drum 8, providing a power between 40 kW and 50 kW, preferably equal to 45 kW. In alternative embodiments, not illustrated, the number of resistors and their power can vary as a function of the size of the plant 1 and the number of tires to be processed.

[0028] The plant 1 further comprises drive means 5 associated with the drum 8. Such drive means 5 have the function of rotating the drum 8. In particular, the drive means 5 comprise a first shaft 56 extending from the drum 8 at the rotation axis R and which passes through the outer wall 21.

[0029] With particular reference to figure 5, it should be noted that the first shaft 56 comprises a first end 561, located at the drum 8 and a second end 562 located outside the rear portion 212 of the outer wall 21. The drive means 5 further comprise a pinion 54 associated with the second end 562 of the first shaft 56. Such drive means 5 also comprise a drive chain 53 and a first motor 51, preferably electric. The chain 53 connects the pinion 54 to the first motor 51. In particular, by means of the chain 53, the first motor 51 transmits the rotational movement to the first shaft 56 which rotates the drum 8 about the rotation axis R.

[0030] The plant 1 comprises a seal 7 placed between the first shaft 56 and the outer wall 21, in particular between the second end 562 of the first shaft 56 and the rear portion 212 of the outer wall 21. As illustrated in figure 6, the seal 7 is defined by a gap 72 located at the first shaft 56 and in fluid communication with the chamber 2. The plant 1 further comprises a source 71 of inert gases which introduces inert gases, preferably nitrogen, inside the gap 72. Advantageously, the seal 7 prevents the vapours produced by the pyrolysis from escaping towards the outer environment directly from the chamber 2 and oxygen from entering from the environment outside the chamber 2.

[0031] The plant 1 comprises a screw 27 arranged along the lower portion 29 of the chamber 2, in a direction substantially parallel to the rotation axis R and adapted to recover a part of the solid pyrolysis residues. The screw 27 has a first end portion 271 near the door 25 and a second end portion 272 near the rear portion 212 of the outer wall 21. Said screw 27 has a second shaft 57 which crosses the outer wall 21 at the second end portion 272. The plant 1 comprises a second motor 52, preferably electric, connected to the screw 27 by means of the second shaft 57. The second motor 52 rotates the screw 27 by means of the second shaft 57.

[0032] The plant 1 comprises a support 55 fixed to the legs 22 which support the chamber 2 near the rear portion 212 of the outer wall 21. The support 55 supports the first motor 51 and the second motor 52.

[0033] The plant 1 comprises a collection duct 24 located at the end portion 272 of the screw 27. Rotating, the screw 27 directs the carbon black powder towards the collection duct 24. The collection duct 24 is adapted to receive the carbon black powder from the drum 8.

[0034] A lever 241 is located outside the collection duct 24. In particular, the lever 241 is switchable between a closing configuration and an opening configuration. When the lever 241 is in the closing configuration, the collection duct 24 internally retains any carbon black powder present. In the opening configuration, the lever 241 opens the collection duct 24, which releases the carbon black powder by gravity. The carbon black powder is thus deposited in a special container (not shown in the appended drawings), located below the collection duct 24.

[0035] The plant 1 further comprises a control unit 4. Such a control unit 4 is configured to operate the first motor 51 and adjust the movement of the drum 8 according to at least a first and a second operating mode.

[0036] In the first operating mode the drum 8 rotates, alternately clockwise and counterclockwise, by a maximum angle between 80° and 100°, preferably 100°. The first operating mode corresponds to the tire heating and degradation by means of the pyrolysis reaction.

[0037] Advantageously, the rotation of the drum 8 during the first operating mode, together with the presence of the projections 84 inside the compartment 82, makes the degradation of the tires moving inside the drum 8 more efficient. In fact, the projections 84 hit against the tires during the movement of the drum 8, further favouring their degradation.

[0038] During the first operating mode the control unit 4 also adjusts the operation of the heating means 9 surrounding the drum 8. Such heating means 9 heat the drum 8 until a temperature between 400 °C and 800 °C, preferably equal to 600 °C, is obtained in the compartment 82.

[0039] The control unit 4 is further configured to operate in a second operating mode which is activated once the first operating mode is finished. The first operating mode is completed when the pyrolysis reaction is completed.

[0040] In the second mode the control unit 4 operates the first motor 51 to fully rotate the drum 8, bringing the apertures 81 to face the screw 27 at least once. Thereby, the carbon black powder is filtered by the net located at the apertures 81. The carbon black powder thus exits by gravity from the drum 8 to deposit on the screw 27, leaving only the steel components of the solid residues of the tires inside the drum 8. Such steel components are then manually removed from the compartment 82 by opening the door 25 once the second operating mode is finished.

[0041] At the same time, in the second operating mode, the control unit 4 operates the second motor 52 which rotates the second shaft 57 and therefore the screw 27, for collecting the carbon black powder.

[0042] To dispose of the gaseous pyrolysis products, the upper portion 28 of the chamber 2 has two exhaust pipes 23 which convey the gases and vapours produced by the pyrolysis from the chamber 2 to the condensing device 3. The exhaust pipes 23 are provided with valves 231. The valves 231 are arranged to open with increasing pressure inside the chamber 2. The condensing device 3, illustrated in figures 6 and 7, comprises a metal coil 34 therein, preferably stainless steel, containing a fluid therein, preferably water at room temperature. Following the condensation, a highly flammable gas oil is obtained which is conveyed through a collection pipe 31 to a container 32 located below the condensing device 3. The condensing device 3 has an inverted pyramid shape which directs the gas oil towards the collection pipe 31 by gravity. The gases resulting from the condensation are lastly conveyed to the hydraulic guard 6 by means of an inlet pipe 33.

[0043] The hydraulic guard 6, illustrated in figure 10, preferably has the shape of a hollow cylinder. In use, the hydraulic guard 6 is filled with water preferably for a height between 200 and 300 mm, even more preferably equal to 250 mm. Thereby, the plant 1 is kept at a slightly higher pressure to avoid the entry of fluids, especially oxygen, from the outer environment.

[0044] The hydraulic guard 6 has a channel 62 connected in fluid communication with the coil 34 of the condensing device 3. The channel 62 promotes a recirculation of water between the coil and the hydraulic guard 6. In particular, the channel 62 keeps the water level within the hydraulic guard 6 constant. The inlet pipe 33 opens below the water level of the hydraulic guard 6. The gases thus bubble towards the empty portion of the hydraulic guard 6. From here, the gases pass to a release duct 61 which expels the gases to the outer environment. Before being expelled from the release duct 61, the gases are burned by a live flame torch (not shown in the appended drawings). A gas analyser (not shown in the appended drawings) is optionally present before the torch, inside the release duct 61. Such an analyser allows detecting the completion of the pyrolysis process when the presence of methane within the exhaust gas is no longer detectable.

Claims

1. A waste tire disposal plant (1) comprising: - a treatment chamber (2) adapted to receive the tires for disposal and having an outer wall (21) and an upper portion (28) and an opposite lower portion (29); - a condensing device (3) in fluid communication with the treatment chamber (2) for at least partially condensing the vapors from the chamber (2), - heating means (9) located inside the chamber (2) and outside the drum (8), said heating means (9) surrounding the drum (8) and radiating heat to the drum (8) - a drum (8) located within the chamber (2) and having a compartment (82) for holding the tires for disposal, the compartment (82) having an inner surface (83), the drum (8) being rotatable about a rotation axis (R) for moving the tires, - drive means (5) associated with the drum (8) to rotate it about the rotation axis (R), the drive means (5) comprising a first shaft (56) extending from the drum (8) at the rotation axis (R) and through the outer wall (21), - a seal (7) between the first shaft (56) and the outer wall (21), - a gap (72) at the first shaft (56) which is in fluid communication with the chamber (2), the gap (72) defining the seal (7), - a source (71) of inert gases configured to introduce an inert gas, preferably nitrogen, into the gap (72), - a screw (27) arranged along the lower portion (29) in a direction substantially parallel to the rotation axis (R) for recovering part of the solid pyrolysis residues, wherein the drum (8) has a plurality of apertures (81) configured to filter out the solid residues and direct a part thereof from the drum (8) to the screw (27), and wherein the chamber (2) has a collection duct (24) associated with the screw (27) and adapted to receive the material collected and guided by the screw (27), and comprising a control unit (4) associated with the drum (8) and configured to move it according to a first operating mode in which the drum (8) rotates about the rotation axis (R) alternately clockwise and counterclockwise through a maximum angle of 80° to 100° and according to a second operating mode in which the drum (8) completes at least one full rotation, thereby causing the apertures (81) to face the screw (27) at least once.

2. A plant (1) as claimed in claim 1, wherein the drum (8) comprises at least one projection (84) extending away from the inner surface (83).

3. A plant (1) as claimed in claim 1 or 2, wherein the drive means (5) comprise a drive chain (53) and a first motor (51), said chain (53) being connected to the first shaft (56) and to the first motor (51).

4. A plant (1) as claimed in any claims from 1 to 3, wherein during the first operating mode the control unit (4) also adjusts the operation of the heating means (9) surrounding the drum (8).

5. A plant (1) as claimed in any claims from 1 to 4, comprising a second motor (52) connected to the screw (27) by means of a second shaft (57).

6. A plant (1) as claimed in previous claim, wherein during the second operating mode the the control unit (4) operates the first motor (51) to fully rotate the drum (8), bringing the apertures (81) to face the screw (27) at least once and at the same time the control unit (4) operates the second motor (52) which rotates the second shaft (57) and therefore the screw (27).