DE2920383A1 - Removing steel particles from thermally disintegrated old tyres - using sand blasting and reducing sand carry-over by concentrating particles magnetically in fluidised bed - Google Patents

Abstract

Steel particles are removed from rubber derived from old tyres disintegrated thermally with the aid of sand blasting by fluidising the sand layer contg. the particles with an auxiliary medium and concentrating the particles magnetically before their removal. Appts. includes a reactor (4) in which the waste rubber is thermally disintegrated with the aid of a sand blasting process. Reactor has a vertically downwardly directed discharge tube (13) terminating above a discharge tray (14) subjected to vibrations. Fluidisation is effected by nozzles (15,18) disposed above respective annular magnets (16,19). Magnets are arranged about the tube (13) with radial clearance for forced cooling. Magnets serve for concn. of the steel particles. Least possible amt. of sand particles is carried over with the removed steel particles.

Description

Title: Method and device for discharging steel parts

a reactor for the thermal decomposition of old tires.

The invention relates to a method and an associated device for discharging steel parts from rubber and plastic waste, in particular from Scrap tires, with the waste thermally decomposed and partially gasified in a sand fluidized bed and the steel parts are withdrawn from the sand fluidized bed.

Such a method is in the as yet unpublished patent application P 28 26 918.3. According to one embodiment of the method mentioned The incombustible ones contained in the old tires are used to reinforce the tires Steel parts are removed together with the sand by a discharge belt and the mixture then separated mechanically and magnetically. The sand is returned to the reactor. With this procedure, especially in the case of large systems, an undesirable high proportion of sand can be removed from the reactor together with the steel parts. This proportion of sand entails a loss of heat for the process and is a burden also the downstream facilities.

The invention is based on the object of a discharge method of To develop the type mentioned in such a way that the smallest possible amount of sand is discharged together with the steel parts.

This object is achieved according to the invention in that below the sand fluidized bed a vortex state by blowing in a further fluidizing medium is maintained in which the steel parts are magnetically concentrated before they are deducted. A device is proposed for carrying out the method in which the drain pipe is provided with nozzles for the supply of a swirling medium and above the nozzles is surrounded on the outside by a ring-shaped magnet, its used Field lines run essentially in the axial direction of the drain pipe and at the the excitation of the magnet, the supply to the nozzle and the drive of the extraction element are in operative connection.

In the magnetic field of this magnet, those slipping out of the reactor will be and steel parts that sink in the drain pipe and that circulate in the fluidized bed held. There is thus a concentration of the steel parts in that of the field lines the magnet detected area of the drain pipe instead. If a sufficiently high Enrichment of the steel parts is present in this area after switching off the Magnets and the supply of the swirling medium to the nozzles actuate the discharge element and removed a subset of steel parts and sand. In this way a mixture of steel and sand can be produced with a high concentration of steel parts according to a given time cycle subtracted from. The timing is calculated from the amount of used tires used. It is also possible to draw off the mixture as a function of a concentration measurement control in the area of the magnet.

An embodiment of the invention is shown in the drawing and is described in more detail below. The drawing shows schematically a longitudinal section through a system for recycling old tires with a discharge device according to the invention.

From an addition bunker 1 scrap tires are a schematic indicated lock system supplied, which is formed by two slides 2 or flaps is. From there, the shredded tires get into a housing part 3, the exit of which opens into a reactor 4. A metering wheel arranged in the outlet of the housing part 3 5 ensures a quasi-continuous and adjustable mass throughput in the Reactor 4.

The reactor 4 is refractory bricked and has in its lower Part a conical inflow base 6. Above the inflow base 6 is on a A sand fluidized bed is maintained as described in more detail below. Within The scraps of used tires are thermally decomposed in the fluidized bed of sand. The for The heat required for decomposition is generated by partial gasification of the shredded tires upset. The product gas that is produced during the decomposition and contains soot becomes Discharged via a product gas line 7 from the upper part of the reactor 4 and directly directed to the place of use.

To feed in the sand it opens into the upper part of the reactor 4 a sand feed line 8 which is fed from a sand addition bunker 9. In the sand feed line 8, a metering element, for example a cellular wheel 10, is arranged. The cell wheel 10 can be bypassed via a lockable secondary line 11.

Nozzles 12 are guided through the inflow base 6, through which air in the reactor 4 is blown. The air also serves as a fluidizing medium for the fluidized bed of sand and as a gasification medium for the tire chips.

The conical inflow base 6 merges into a central drain pipe 13. With the help of a discharge member 14 are through the drain pipe 13 in the thermal Decomposition of remaining components, such as those from the reinforcement of the tires Serving wires and wire meshes existing steel parts withdrawn from the reactor 4.

In order to get as little sand as possible out of the drain pipe 13 together with the steel parts subtract, there is an enrichment of the steel parts within the drain pipe 13 performed. For this purpose, the drain pipe 13 is provided with nozzles 15 for the supply of a Fluidizing medium, preferably air, to generate a fluidized bed above the Nozzles 15 provided. At the same time, the drain pipe 13 is above these nozzles 15 on the outside surrounded by an annular magnet 16, which is in an annular shape, not shown Housing is arranged. The magnet 16 is water-cooled and arranged such that its field lines used run approximately in the axial direction of the drain pipe 13.

The magnet 16 can consist of a plurality of ring-shaped ones arranged one above the other Solenoid coils exist. The annular gap 17 between the housing of the magnet 16 and the drain pipe 13 can be equipped with forced cooling, e.g. air or water cooling, be provided.

Above the magnet 16 is the drain pipe 13 with another Nozzle ring 18 provided. This nozzle ring 18 alternates with the nozzles 15 vortex air is blown into the drain pipe 13.

When the magnet 16 is energized, its area inside the drain pipe 13 the sinking steel parts and those circulating in the fluidized bed were held. The concentration of the steel parts at this point can be achieved by an inductive Wise working concentration measuring device can be determined. This exists from a coil, the inductance of which is measured when a voltage is applied. the The amount of inductance is a measure of the amount that is present at this point Steel parts. A special coil can be used, or alternatively one of the ring-shaped ones Coils of the magnet 16 are used.

The excitation of the magnet 16, the air supply to the nozzles 15 and 18 and the drive of the extraction element 14 are in operative connection with one another. The establishment works in the following way: Is there a sufficient concentration of steel parts in the area of the magnet 16, the drive of the trigger element 14 receives a signal, to subtract a certain volume. Shortly before, the air flow through the nozzles 15 are diverted to the nozzle ring 18 and the magnet 16 is switched off. To the pull-off process, the magnet 16 is switched on again and the air is on again the nozzles 15 diverted.

The drain pipe 13 can be located below the magnet 16 and the nozzles 15 be surrounded by an annular additional magnet 19, the in its structure of the magnet 16 corresponds. The magnetic fields of the magnet 16 and the additional magnet 19 are separated from each other. The additional magnet 19 has the task of being in the drain pipe 13 to hold steel parts removed from the area of the magnet 16 at this point, so that they are not caused by the air that is blown in through the nozzles 15 again and / or conveyed upwards by the suction of the magnet 16.

Spray nozzles 20 are arranged below the magnet 16, through which a coolant such as water or water vapor can be blown into the drain pipe 13 can. In this way, the temperature within the fluidized bed can be controlled, so that a sintering together of the steel parts with the sand or a slag formation and thus clogging of the drain pipe 13 can be counteracted. To the The drain pipe 13 below the magnet and inflow system can provide further cooling be provided with a cooling jacket 21 through which water or air flows.

In order to prevent the steel parts / sand mixture from sinking when the discharge element 14 is actuated To facilitate, the drain pipe 13 is below the magnet and impregnation system enlarged in diameter. The extended part of the drain pipe 13 goes into an easy in the conveying direction of the take-off element 14, the outlet part 22, which is bent into the Housing of the discharge element 14 opens. The outlet part 22 has one again enlarged diameter and can be pushed onto the drain pipe 13.

The length of the drain pipe 13 is dimensioned so that the existing in it Bulky column seals the reactor 4 against the external pressure. Must the drain pipe 13 be made shorter because of the lack of height, the discharge element 14 is closed capsules. In this case 14 discharge locks are to be provided behind the discharge element.

The discharge element 14 can be a steel conveyor belt or a vibrating chute be. The vibrating chute has a closed bottom 23 in the entrance part, connected to the grate bars 24 connected to the bottom 23. On the grate bars Z4 the coarse components are separated off. The fine steel parts and the sand are a downstream of the discharge member 14 magnetic separation device 25, the is designed as a magnetic roller or as a belt magnet, supplied. The steel parts the discharge element 14 and the magnetic separating device 25 pass into a pressing device 26th

The sand is collected in a sand bunker 27. From sand bunker 27 the sand will be a pneumatic and mechanical conveyor according to the path 28 fed to the sand addition bunker 9.

A corresponding amount of sand is poured over during or after the removal the cellular wheel 10 is refilled in the reactor 4. The amount of sand to be replaced can by means of a level measuring device which determines the position of the surface of the fluidized bed 29 or a pressure differential measurement can be conveyed. The level measuring device is electrically connected to the drive of the cell wheel 10.

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Claims (13)

PATENT CLAIMS 1. Method for removing steel parts from rubber and plastic waste, especially from used tires, with the waste inside thermally decomposed in a fluidized bed of sand with the addition of a gasification medium and are partially gasified and the steel parts are withdrawn from the sand fluidized bed, as a result, that it is blown in below the fluidized bed of sand a further vortex medium, a vortex state is maintained in which the Steel parts are magnetically concentrated before they are peeled off. 2. Apparatus for performing a method according to claim 1 below Use of a reactor that merges into a discharge pipe to which a discharge element is connected, in that the drain pipe (13) provided with nozzles (15, 18) for the supply of a swirling medium and above the nozzles (15) is surrounded on the outside by an annular magnet (16) whose field lines are used run essentially in the axial direction of the drain pipe (13) and that the excitation of the magnet (16), the supply to the nozzles (15, 18) and the drive of the extraction element (14) are in vortex connection. 3. Apparatus according to claim 2, characterized in that g e k e n n z e i c h n e t that the magnet (16) is cooled. 4. Device according to claims 2 or 3, characterized g e k e n n z e i c h n e t that the annular gap (17) between the drain pipe (13) and the magnet (16) is provided with forced cooling. 5. Device according to one of claims 2 to 4, characterized g e k e n n z e i c h n e t that in the area of the magnet (16) an inductive concentration measuring device is provided. 6. Device according to one of claims 2 to 5, characterized g e k e n n z e i c h -n e t that the drain pipe (13) below the magnet (16) of a Additional magnet (l9) is surrounded and that both magnets (16, 19) separate magnetic fields exhibit. 7. VorrichLung according to one of claims 2 to 6, characterized g e k e n n z e i c h -n e t that the discharge element (14) via a separating device (25), a conveyor and a sand addition bunker (9) connected to a feeder (10) is controlled by a level measuring device (29). 8. Device according to one of claims 2 to 7, characterized g e k e n n z e i c h -n e t that below the magnet (16) spray nozzles (20) for a coolant open into the drain pipe (13). 9. Device according to one of claims 2 to 8, characterized g e k e n n z e i c h -n e t that the drain pipe (13) below the magnet and inflow system (15, 16, 18, 19) is surrounded by a cooling jacket (21). 10. Device according to one of claims 2 to 9, characterized g e k e n n z e i c h -n e t that the drain pipe (13) is below the magnet and inflow system (15, 16, 18, 19) expanded. 11. Device according to one of claims 2 to 10, characterized g e k e n n z e i c h -n e t that the drain pipe (13) with one in the conveying direction of the drainage duct (14) curved outlet part (22) is provided. 12. Device according to one of claims 2 to 11, characterized g e k e n n z e i c h -n e t that the discharge element (14) from a vibrating chute with a closed Floor (23) and downstream grate bars (24) consists. 13. Device according to one of claims 2 to 12, characterized g e k e n n z e i c h -nest that the discharge element (14) and the magnetic separation device (25) a pressing device (26) is connected downstream.