A METHOD FOR THE CONTINUOUS THERMAL PROCESSING OF USED, DAMAGED OR OTHERWISE DEGRADED TYRES, AND A DEVICE FOR CARRYING OUT THIS METHOD

Abstract

Continuous thermal processing of used or damaged tires carried out by thermal decomposition in a closed vertically oriented reaction space in the presence of a controlled flow of air blowing into it from below, by the action of flue gases passing from the tires ignited at the bottom of the reaction space upwards, along the tires stacked and continuously replenished in the reaction space to form their thermal decomposition products, discharged from the reaction space to be further processed.

Claims

1. A method of continuous thermal processing of used or damaged or otherwise degraded tires, comprising: thermally decomposing the tires in a closed vertically oriented reaction space in the presence of a controlled flow of air blowing into it from below, by the action of flue gases passing from the tires ignited at a bottom of the reaction space upwards, along the tires stacked and continuously replenishing the tires in the reaction space to form thermal decomposition products of the tires, discharging the thermal decomposition products from the reaction space to be further processed, wherein, in a first starting phase, the reaction space is first filled with tires to be processed, the tires ignite at a bottom of the reaction space at maximum air supply, and, in a second phase after reaching a temperature of 700 to 850° C. in the lower part of the reaction space and 150 to 250° C. in the upper part of the reaction space, by reducing the air supply, the temperatures in in the lower part and in the upper part of the reaction space stabilize at constant values at which thermal decomposition of the processed tires takes place in the second phase at least until such a number of tires is added to the reaction space with restricted air access from its surroundings, that the proportion of their weight, expressed in kg, and the size of the transverse area of the reaction space, expressed in m.sup.2, reaches a value of 1,900 to 2,100 and at the same time a hot carbon bed is formed at a height of at least 0.7 to 1.2 metres from the bottom of the reaction space, and, in a third phase, with further continuation of the thermal decomposition until its completion with the continuous refilling of the reaction space with the tires to be processed, equilibrium is set by increasing the air supply again with temperatures of 900 to 950° C. in the lower part of the reaction space and 380 to 450° C. in its upper part, wherein aerosol is discharged from its upper part of the reaction space for further processing, formed by gaseous products from the thermal decomposition of tires, in which micro particles from the decomposition of low molecular weight substances are dispersed, and from its lower part the resulting solid residues of thermal decomposition of tires are removed.

2. The method according to claim 1, wherein the aerosol formed in the reaction space and discharged from its upper part for further processing is, after its partial cooling to 180 to 250° C., cooled down in at least two consecutive cycles and at the same time is subjected to separation of liquid and gaseous phases by the action of frictional mechanical forces, after which the separated liquid products are subjected to gasification and, after perfect dispersion they are combusted in a sub-stoichiometric amount of air at temperatures from 1,100 to 1,500° C. and at a mixing ratio of 3 to 7 parts by weight of air per one part by weight of incoming liquid, wherein the resulting flue gases are cooled by dispersing water to a temperature of 250 to 300° C. and then led to the separation of soot from the gaseous phase, which is removed from this process to after burn CO and to add calcium oxide or carbonate to capture sulphur dioxide and form energy gypsum (CaSO4).

3. The method according to claim 1, wherein, when the hot carbon bed is too high, a hot mass is forced out of the lower part of the reaction space into a secondary space secured against ingress of air, in which steel wires present in the hot mass separate from a remaining portion of the hot mass and, when hot, the wires are mechanically compressed or wound into twines, wherein a hot residue of the carbon bed falls through a sieve during mechanical working of the wire to a lower part of the space below the reaction space, where a temperature of the residue is reduced by spraying with water and the residue is removed outside the space connected to the reaction space.

4. The method according to at least one of the preceding claims, wherein a reaction of tire decomposition in the reaction space is carried out under a negative pressure of 5 to 10 kPa.

5. A device for carrying out the method according to claim 1, comprising a reactor for thermal decomposition of tires, the reactor having an upper part in which a feeding chamber is arranged with a conveyor for loading the reactor with tires to be processed and for continuously replenishing them in an inner space of the reactor under which at least one outlet opening is arranged in the reactor for removal of aerosol formed by gaseous products of thermal decomposition with dispersed micro particles of low molecular weight substances, and the reactor having a lower part in which an outlet chamber is arranged for expelling solid residues of the thermal decomposition, wherein each outlet opening for discharging aerosol from the reactor is connected via a cooled pipe to a hot gas separator, an outlet of the hot gas separator being connected to an air-cooled tube cooler connected to a water-cooled tube cooler, an outlet of the tube cooler being connected to an inlet of a cold gaseous medium separator, wherein both the hot gas separator and the cold gaseous medium separator are connected by outlets thereof for the discharge of liquid products via a collecting vessel, a reservoir and a dosing pump to a retort with an air dispenser, from which air dispenser resulting flue gases are led to a cooling zone with a system of water showers and a battery of cyclones for separating soot generated in the battery into bag filters and discharge of the soot by end screw conveyors outside the device, and wherein the hot gas separator and the cold gaseous medium separator are connected by their outlets for the discharge of gaseous products to an end combustion unit for energetic utilization of residual hydrocarbons in the gases and for elimination of SO2 emissions in the flue gases, to which outlets of the gaseous components from the retort are also connected via a fan and a connecting pipe, wherein the outlet chamber in the lower part of the reactor is provided with an outlet screw conveyor for removing excess hot mass from the lower part of the reactor towards a secondary space and for separating the hot mass into a fine carbon fraction and a fraction of steel wires, and the reactor is provided via its insulated jacket with a set of temperature sensors for measuring temperatures in its interior along its entire height, which temperature sensors are connected by outputs thereof to a control operating unit of the reactor together with an output of a digital scale with data on an amount of mass of tires processed in its inner space.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0020] The invention is further explained by means of drawings of an exemplary embodiment of the device for carrying out the method of thermal continuous processing of used, damaged or otherwise degraded tires according to the invention, where FIG. 1 shows the whole assembly of this device, FIG. 2 shows a section of its reactor and FIG. 3 shows a detail of the lower part of this reactor.

DETAILED DESCRIPTION

[0021] According to FIG. 1, the device for carrying out the method in the illustrated exemplary embodiment of the invention consists of or comprises two technological units, namely section A and section B. Section A includes all technological operations concerning tire decomposition, and section B then serves to process the obtained liquid hydrocarbons and produce rubber soot, wherein in the technological nodes associated with the elimination of sulphur dioxide, both these sections use a common end element of energetic after-burning of gases.

[0022] Section A is formed by a reactor 1, which is provided with a conveyor 4 in the form of a lift for loading its upper feeding chamber 2 with processed tires and for their continuous replenishment via this upper feeding chamber 2 into its inner reaction space. Reactor 1 is further provided with a control operating unit 34 and digital scale 35, delivering to the control operating unit 34 data on the amount of mass in the reactor 1. A closed outlet chamber 6 is connected to the reactor 1 in its lower part, in which devices for handling hot waste ashes and for their transport outside its space are located. Reactor 1 is further equipped with a pair of systems for the removal of gaseous products formed in it, for their cooling and their division into liquid and gaseous phases. Each of the systems consists of or comprises a hot gas separator 7, to the supply of which one of the branches of the discharge of these gaseous products from the reactor 1 is connected via a cooled pipe 38, the reactor being for this purpose, as can also be seen in FIG. 2, a pair of outlet openings 5. The outlet of the hot gas separator 7 is then connected to an air cooled tube cooler 8, which is structurally connected to a water-cooled tube cooler 9, the outlet of which is connected to the inlet of a cold gaseous medium separator 10. The separators 7 and 10 of both systems are connected by their outlets for the discharge of liquid products via unspecified shut-off valves to a collecting vessel 11 from which the liquid products are pumped into a reservoir 12 and from there they are dosed into section B. Still in section A, the gaseous products are passed from the last of the series of separators 10 via the closures of the individual branches with non-return valves to be after-burned to the end combustion unit 23 for energetic utilization of residual hydrocarbons in the gases and to eliminate SO2 emissions in the flue gases. This unit 23 comprises a burner (not shown in more detail), an air heat exchanger, a dosing device intended for injecting calcium oxide or micronized limestone into the incoming air stream for combustion, and from the cyclone solids separator in the flue gases to capture the gypsum formed.

[0023] Section B in this exemplary embodiment is formed from the outside by a thermally insulated cylindrical retort 13 provided with a refractory lining with an internal diameter of 0.45 m and a length of 1.5 m, which is provided with an air dispenser 14 and is connected via a piston dosing pump 15 to a reservoir 12 of liquid products. The retort 13 is followed by a cooling zone 16 of the flue gases emerging from it, which consists of or comprises a set of water showers 1_7 and a battery of cyclones 18 for their further cooling and for the separation of the soot formed. The outlet of the last cyclone 18 is then connected to a pair of bag filters 19, wherein the resulting soot deposited at the bottom of both the cyclones 18 and the bag filters 19 are discharged outside the device by a pair of end screw conveyors 20. The gaseous products from the process of soot production are returned by a fan 21 through a connecting pipe 22 back to section A to the end combustion unit 23.

[0024] Another technological node of the device according to the invention is the part of solid waste management, which is connected to its outlet chamber 6 which is shown in more detail in FIG. 3. This part is formed by an outlet screw conveyor 24 for removing excess hot mass from reactor 1 towards the secondary space 25 and for its separation into a fine carbon fraction, falling through sieves in the walls of the outlet screw conveyor 24 into the collecting space 26, and into a steel wire fraction which is hot deformed by the outlet screw conveyor 24 and ends up as an irregularly compressed formation in the secondary space 25, from which it is periodically removed after opening the exit door 27. The reactor 1 is provided with a bottom door 31 in its lower part in order to remove excess hot mass, wherein the carbon fraction below the outlet screw conveyor 24 is cooled by spraying water to a temperature below 200° C. after re-closing the bottom door 31 and transferred to a sealed steel tank 28.

[0025] As can be seen in more detail in FIG. 2, the reactor 1 is provided via its insulated jacket 32 with a set of superimposed temperature sensors 33 at 1-metre distances for measuring temperatures in its interior over its entire height, and its lower part has a conically downwardly narrowing profile 36 with controlled air inlets 29 connected to the air supply via a pair of control valves 30. In this particular embodiment, the reactor 1 has the shape of a prism with a square base with an edge length of 1.1 m and its height from the bottom to the outlet openings 5 is 7 metres in this device. The feeding chamber 2, as also shown in FIG. 2, is equipped with a pair of feeding closures 3, 37 to prevent ingress of air into the reactor 1, of which the upper tilting feeding closure 37 is operated by mechanism of the conveyor 4 and the lower sliding feeding closure 3 is actuated autonomously.

[0026] In carrying out the method of thermal continuous processing of tires according to the invention, in this exemplary embodiment thereof, the tires to be processed are randomly stacked on top of each other in the closed space of the reactor 1 and ignited via an open door 31 at the bottom of the reactor 1. After flaring up, the bottom door 31 is closed and air is sucked into the closed space through the fully open control valves 30.

[0027] After reaching a mass temperature at the bottom of the reactor 1 of 750° C., the air flow is adjusted by throttling and opening the control valves 30 to reach a temperature of 820° C., wherein the free space in the reactor 1, after deformation and decomposition of the tires in its lower part, is continuously replenished by additional tires from the feeding chamber 2. During further gradual heating of the reactor 1, after establishing a temperature gradient of values between 700 and 850° C. in the lower part of the reactor 1 and 150 to 250° C. in its upper part, this equilibrium state is left without interfering with the regulation of air flow. In this state, a hot carbon layer is formed, the height of which is estimated from the number of tires introduced into reactor 1. After 2.5 hours of operation, the height of this bed was estimated to be about one metre. Then, the equilibrium state is set by the air supply control valves 30 with a temperature gradient of 900 to 950° C. in the lower part of the reactor and 380 to 450° C. in its upper part or at the outlet openings 5 in the reactor 1 of the gaseous products formed from the reactor. In this mode, 19,150 kg of tires were processed in 18 hours.

[0028] After a reserve of 800 litres, the liquid products began to be processed to soot in the retort 13. At a set flow rate of the dosing pump 15 of 600 litres per hour, the air flow to the retort 13 was set to such an amount that the average temperature of output gases was 1,280° C. The produced soot in the amount of 6,095 kg served as test samples for setting the application possibilities of this raw material in the rubber industry or other sectors.

INDUSTRIAL APPLICABILITY

[0029] The method and device according to the invention are widely applicable in the disposal of tires of different types and sizes while using quality products obtained from them.

REFERENCE SIGNS LIST

[0030] 1-reactor [0031] 2-feeding chamber [0032] 3-lower feeding closure [0033] 4-conveyor [0034] 5-outlet opening [0035] 6-outlet chamber [0036] 7-hot gas separator [0037] 8-air-cooled tube cooler [0038] 9-water-cooled tube cooler [0039] 10-cold gaseous medium separator [0040] 11-collecting vessel [0041] 12-reservoir of liquid products [0042] 13-cylindrical retort [0043] 14-air dispenser [0044] 15-dosing pump [0045] 16-cooling zone [0046] 17-water showers [0047] 18-cyclones [0048] 19-bag filters [0049] 20-end screw conveyor [0050] 21-fan [0051] 22-connecting pipe [0052] 23-end combustion unit [0053] 24-outlet screw conveyor [0054] 25-secondary space [0055] 26-collecting space [0056] 27-exit door [0057] 28-tank [0058] 29-controlled air inlet [0059] 30-control valves [0060] 31-bottom door [0061] 32-insulated reactor jacket [0062] 33-temperature sensors [0063] 34-control operating unit [0064] 35-digital scale [0065] 36-conically narrowed profile [0066] 37-upper feeding closure [0067] 38-cooled pipe